Modular full-spectrum high-efficiency electromagnetic shielding flexible fabric and preparation method thereof

Abstract

This invention discloses a modular full-spectrum high-efficiency electromagnetic shielding flexible fabric and its preparation method, belonging to the field of electromagnetic shielding material design and preparation. The preparation method of this invention includes the following steps: (1) using a magnetron sputtering system to perform metal deposition treatment on the fabric to obtain a flexible conductive fabric A; (2) using vacuum coating technology to perform metal deposition treatment on the surface of a polymer film to obtain a high-toughness conductive film B; (3) mixing carbon-based microwave absorbing material and polymer with solvent uniformly and curing to obtain a microwave absorbing layer C of a certain thickness; (4) arranging and encapsulating the functional modules obtained in steps (1), (2), and (3) in a specific arrangement to obtain the modular full-spectrum electromagnetic shielding flexible composite fabric.

Description

Technical Field

[0001] This invention belongs to the field of shielding material design and preparation, specifically relating to a modular full-spectrum high-efficiency electromagnetic shielding flexible fabric and its preparation method. Background Technology

[0002] High-efficiency modular electromagnetic shielding flexible fabric is a material that can be appropriately adjusted according to different application scenarios to significantly reduce the intensity of electromagnetic radiation in various application environments. The effective shielding of multi-spectral electromagnetic wave pollution by modular full-spectrum high-efficiency electromagnetic shielding flexible fabric has significant practical value in military, civilian, and electronic components applications. Furthermore, its modular and multi-combination product characteristics meet the development requirements of various industries to effectively reduce electromagnetic wave pollution in the environment while maintaining appropriate technical costs. Therefore, the research and development of modular full-spectrum high-efficiency electromagnetic shielding flexible fabric is of great significance. Existing electromagnetic shielding materials have poor multi-spectral electromagnetic shielding effects, mainly due to their inability to effectively shield low-frequency electromagnetic waves and the inability to adapt the shielding material composition to different application scenarios, resulting in high production costs and ineffective shielding performance. Summary of the Invention

[0003] [Technical Issues]

[0004] Currently, the application range of existing electromagnetic shielding composite materials is limited, and it is difficult to achieve limited shielding in the low-frequency band. Furthermore, the inability to appropriately modularize multi-layer shielding materials according to different application scenarios results in high application costs for this type of shielding material in multiple scenarios.

[0005] [Technical Solution]

[0006] To address the aforementioned issues, this invention first deposits a highly conductive metal layer on the surface of a fabric using magnetron sputtering technology, obtaining a flexible conductive fabric A. Subsequently, a metal of a certain thickness is deposited on the surface of a polymer film using vacuum deposition technology, resulting in a conductive film B that efficiently shields low-frequency electromagnetic waves. Finally, the synergistic effect of carbon-based absorbing materials and polymers forms an absorbing layer C that efficiently absorbs high-frequency electromagnetic waves. By varying the thickness of the metal layer on the fabric or film surface and the content of carbon-based absorbing materials in the absorbing layer, fabrics, films, or coatings with different electromagnetic parameters and shielding or absorption properties are obtained. These are then assembled sequentially and encapsulated to obtain a modular full-spectrum electromagnetic shielding composite fabric.

[0007] The first objective of this invention is to provide a method for preparing a modular full-spectrum electromagnetic shielding flexible composite fabric, comprising the following steps:

[0008] (1) Preparation of conductive fabric A

[0009] A flexible conductive fabric A was obtained by depositing metal on the surface of a fabric using a magnetron sputtering system. Different types of metals and different deposition thicknesses of conductive fabrics were prepared by changing the magnetron sputtering target, sputtering time, and sputtering power.

[0010] (2) Preparation of conductive thin film B

[0011] A high-toughness conductive film B is obtained by performing metal deposition on the surface of a polymer film using vacuum deposition. Different types of metals and different deposition thicknesses of conductive films are prepared by changing the vacuum deposition target, deposition time, and deposition power.

[0012] (3) Preparation of absorbing layer C

[0013] After mixing and dissolving carbon-based microwave absorbing material, polymer, and solvent, the mixture is poured into a specified mold for curing to obtain a microwave absorbing layer C of a certain thickness. The amount of carbon-based microwave absorbing material is varied to prepare carbon-based microwave absorbing layers with different electromagnetic parameters and microwave absorption capabilities.

[0014] (4) Preparation of full-spectrum electromagnetic shielding fabric

[0015] The conductive fabric A, conductive film B, and absorbing layer C obtained in steps (1), (2), and (3) are arranged, combined, and encapsulated to obtain the modular full-spectrum electromagnetic shielding flexible composite fabric.

[0016] In one embodiment of the present invention, the fabric described in step (1) is a blend of one or more fibers, including cotton, linen, wool, silk, asbestos, viscose, nylon, polyester, acrylic, spandex, vellen, polypropylene, and polyvinyl chloride.

[0017] Preferably, the fabric described in step (1) is polyester.

[0018] In one embodiment of the present invention, the fabric thickness in step (1) is 0.05mm-2mm.

[0019] Preferably, the fabric thickness in step (1) is 0.1 mm.

[0020] In one embodiment of the present invention, the target material for magnetron sputtering in step (1) is one or more alloys of nickel (Ni), titanium (Ti), zinc (Zn), chromium (Cr), magnesium (Mg), niobium (Nb), tin (Sn), aluminum (Al), indium (In), iron (Fe), zirconium (Zr), copper (Cu), germanium (Ge), silver (Ag), cobalt (Co), gold (Au), and tungsten (W).

[0021] Preferably, the metal target material in step (1) is nickel (Ni).

[0022] In one embodiment of the present invention, the sputtering time of the magnetron sputtering in step (1) is 10-30 min.

[0023] Preferably, the sputtering time in step (1) is 20 min.

[0024] In one embodiment of the present invention, the sputtering power of the magnetron sputtering in step (1) is 50-150W.

[0025] Preferably, the sputtering power in step (1) is 100W.

[0026] In one embodiment of the present invention, the surface metal thickness of the conductive fabric A in step (1) is 0.1-1 μm.

[0027] Preferably, the surface metal thickness of the conductive fabric A in step (1) is 0.3-0.5 μm.

[0028] In one embodiment of the present invention, the polymer film described in step (2) is one or more of the following: cellulose (CA / CN), regenerated cellulose (RC), polyamide (nylon 6, nylon 66), polysulfone (PS), polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), polypropylene (PP), and polyester (PET).

[0029] Preferably, the polymer film described in step (2) is polyester PET.

[0030] In one embodiment of the present invention, the thickness of the polymer film in step (2) is 0.05 mm to 2 mm.

[0031] Preferably, the thickness of the polymer film in step (1) is 0.1 mm.

[0032] In one embodiment of the present invention, the target material for vacuum coating in step (2) is one or several alloys of nickel (Ni), titanium (Ti), zinc (Zn), chromium (Cr), magnesium (Mg), niobium (Nb), tin (Sn), aluminum (Al), indium (In), iron (Fe), zirconium (Zr), copper (Cu), germanium (Ge), silver (Ag), cobalt (Co), gold (Au), and tungsten (W).

[0033] Preferably, the target material for vacuum coating in step (2) is aluminum (Al).

[0034] In one embodiment of the present invention, the vacuum coating time in step (2) is 5-20 min.

[0035] Preferably, the vacuum coating time in step (2) is 10 minutes.

[0036] In one embodiment of the present invention, the power of vacuum coating in step (2) is 100-300W.

[0037] Preferably, the power of the vacuum coating in step (2) is 200W.

[0038] In one embodiment of the present invention, the surface metal thickness of the conductive thin film B in step (2) is 0.1-1 μm.

[0039] Preferably, the surface metal thickness of the conductive film B in step (2) is 0.15-0.3 μm.

[0040] In one embodiment of the present invention, the carbon-based microwave absorbing material in step (3) is one or more of the following: carbon nanotubes and their derivatives, graphene and its derivatives, carbon black and its derivatives, Mxene and its derivatives, carbon quantum dots and their derivatives, and fullerene and its derivatives.

[0041] Preferably, the carbon-based microwave absorbing material in step (3) is graphene nanosheets.

[0042] In one embodiment of the present invention, the polymer in step (3) is one or more of polypropylene (PP), polyethylene (PP), polyvinyl chloride (PVC), polyester (PET), polyvinylidene fluoride (PVDF), polytetrachloroethylene (PTFE), and polyethylene-vinyl acetate (EVA).

[0043] Preferably, the polymer in step (3) is polyethylene-vinyl acetate (EVA).

[0044] In one embodiment of the present invention, the solvent in step (3) is one or more of ethanol, N,N-dimethylformamide (DMF), N,N-dimethylacetamide (DMAc), acetone, N-methylmorpholine oxide (NMMO), room temperature plasma (AMIMCI), formic acid, acetic acid, trifluoroacetic acid (TFA), trifluoroethanol (TFE), chloroform (TCM), dichloromethane (DCM), hexafluoroisopropanol (HFIP), and tetrahydrofuran (THF).

[0045] Preferably, the solvent in step (3) is dichloromethane.

[0046] In one embodiment of the present invention, the mixing in step (3) is carried out by stirring for 2-4 hours.

[0047] In one embodiment of the present invention, the polymer in step (3) has a mass fraction of 10-30 wt.% in the solvent.

[0048] Preferably, the concentration of the polymer in step (3) is 20 wt.%.

[0049] In one embodiment of the present invention, the concentration of the carbon-based microwave absorbing material in step (3) is 10 wt.% to 50 wt.%.

[0050] Preferably, the concentration of the carbon-based microwave absorbing material in step (3) is 25 wt.%.

[0051] In one embodiment of the present invention, the thickness of the absorbing layer in step (3) is 0.1 mm to 2 mm.

[0052] Preferably, the thickness of the absorbing layer in step (3) is 0.15-0.3 mm.

[0053] In one embodiment of the present invention, the order of the conductive fabric A, conductive film B, and absorbing layer C in step (4) is one or more of the following: CBA, CAB, ACB, ACA, BCB, CAC, CBC, CBCA, CACB, ACBCB, BCACA, ACBCA, BCACA, BCACB, CBCAC, CACBC.

[0054] Preferably, the permutation and combination order in step (4) is CBCAC.

[0055] In one embodiment of the present invention, the encapsulation in step (4) is one or more of high-temperature pressure encapsulation, plastic encapsulation, and plastic shell encapsulation.

[0056] Preferably, the packaging method in step (4) is high-temperature pressure packaging.

[0057] In one embodiment of the present invention, the encapsulation temperature in step (4) is 100-200°C.

[0058] In one embodiment of the present invention, the encapsulation time in step (4) is 5-20 min.

[0059] In one embodiment of the present invention, the encapsulation pressure in step (4) is 2-20 MPa.

[0060] Preferably, the encapsulation temperature in step (4) is 150°C, the encapsulation time is 10 min, and the encapsulation pressure is 10 MPa.

[0061] In one embodiment of the present invention, the thickness of the full-spectrum electromagnetic shielding fabric in step (4) is 0.1 mm to 5 mm.

[0062] The preferred step (4) has a full-spectrum electromagnetic shielding fabric with a thickness of 0.5 mm.

[0063] In one embodiment of the present invention, the conductive fabric A, the conductive film B, and the absorbing layer C in the modular full-spectrum electromagnetic shielding flexible composite fabric work together, wherein the surface metal thickness of A is 0.3-0.5 μm, the surface metal thickness of B is 0.15-0.3 μm, and the thickness of the absorbing layer is 0.15-0.3 mm; and when the surface metal thickness of A is 0.5 μm, the surface metal thickness of B cannot be 0.3 μm and the thickness of the absorbing layer cannot be 0.15 mm at the same time.

[0064] The second objective of this invention is to prepare a full-spectrum electromagnetic shielding fabric based on the above method.

[0065] The third objective of this invention is to provide applications of the aforementioned full-spectrum electromagnetic shielding fabric in the military and electronic component fields.

[0066] [Beneficial Effects]

[0067] This invention addresses the problems of existing electromagnetic shielding materials, such as their inability to effectively shield electromagnetic waves across the entire spectrum and their high cost due to the inability to adapt shielding materials to various application environments. It designs and fabricates a highly efficient modular full-spectrum electromagnetic shielding flexible fabric. This modular full-spectrum electromagnetic shielding flexible fabric can effectively shield high, medium, and low-frequency electromagnetic waves, and the shielding modules can be adaptively adjusted according to different application scenarios. The various modular full-spectrum electromagnetic shielding flexible fabrics prepared by the method described in this invention exhibit excellent shielding performance, significantly superior to most current shielding materials. Furthermore, the shielding modules can be adjusted according to different application scenarios, and the cost control is also significantly better than most current shielding materials. Detailed Implementation

[0068] The preferred embodiments of the present invention are described below. It should be understood that the embodiments are for better explanation of the present invention and are not intended to limit the present invention.

[0069] Source of raw materials

[0070] Polyethylene-vinyl acetate was sourced from Shanghai Maclean Biochemical Technology Co., Ltd., and graphene nanosheets were purchased from Nanjing Xianfeng Nanotechnology Co., Ltd.

[0071] Test method:

[0072] Electromagnetic shielding effectiveness (window method): The electromagnetic shielding effectiveness of the samples in the examples and comparative examples was tested according to the test methods specified in GJB / Z 158-2011 and GJB 5792-2006.

[0073] Example 1

[0074] (1) Place the 10cm×10cm polyester fabric with a thickness of 0.1mm to be treated in the magnetron sputtering system, adjust the sputtering time to 20min, the sputtering power to 100W, and the metal target to nickel (Ni) before surface metal deposition to obtain a conductive polyester fabric A with a surface metal thickness of 0.5μm.

[0075] (2) Place a 10cm×10cm PET film with a thickness of 0.1mm into a vacuum coating system, adjust the vacuum coating time to 10min, the vacuum coating power to 200W, and the metal target to aluminum (Al) before performing surface metal coating to obtain a conductive metal PET film B with a surface metal film thickness of 0.3μm.

[0076] (3) Mix 4g of polyethylene-vinyl acetate (EVA) and 5g of graphene nanosheets with dichloromethane to form a 20g mixed solution. Stir for 3h to completely dissolve the polyethylene-vinyl acetate and uniformly disperse the graphene nanosheets, forming a uniformly mixed solution of polyethylene-vinyl acetate and graphene nanosheets with mass fractions of 20wt.% and 25wt.%, respectively. After standing for 2h to remove bubbles, pour the solution into a custom mold with a depth of 0.5mm and a height of 10cm×10cm. Then dry at room temperature to obtain a 0.15mm microwave absorbing layer C.

[0077] (4) The conductive polyester fabric A, conductive metal PET film B, and wave-absorbing layer C of the specified size obtained in steps (1), (2), and (3) are combined in the order CBCAC, and then high-temperature pressure encapsulation is performed to obtain a modular full-spectrum electromagnetic shielding flexible fabric. The encapsulation temperature at both ends is 150℃, the encapsulation pressure is 20Mpa, and the encapsulation time is 10min.

[0078] The electromagnetic shielding effectiveness was tested using the window method. The shielding effectiveness of the modular full-spectrum electromagnetic shielding flexible fabric obtained in Example 1 in each frequency band is shown in Table 1. It has excellent full-spectrum electromagnetic shielding performance.

[0079] Table 1 Electromagnetic shielding effectiveness at different frequency bands

[0080] Frequency band (Hz) 14K 100K 200K 450M 950M 3G 6G 10G 18G Performance (-dB) 9 23 28 48 48 45 42 40 40

[0081] Example 2

[0082] Example 2 modifies the surface metal thickness of the conductive polyester fabric in step (1) of Example 1.

[0083] (1) Place the polyester fabric with a thickness of 0.1 mm and a size of 10 cm × 10 cm into the magnetron sputtering system, adjust the sputtering time to 10 min, the sputtering power to 100 W, and the metal target to nickel (Ni) before surface metal deposition to obtain a conductive polyester fabric A with a surface metal thickness of 0.3 μm.

[0084] (2) Place a 10cm×10cm PET film with a thickness of 0.1mm into a vacuum coating system, adjust the vacuum coating time to 10min, the vacuum coating power to 200W, and the metal target to aluminum (Al) before performing surface metal coating to obtain a conductive metal PET film B with a surface metal film thickness of 0.3μm.

[0085] (3) Mix 4g of polyethylene-vinyl acetate (EVA) and 5g of graphene nanosheets with dichloromethane to form a 20g mixed solution. Stir for 3h to completely dissolve the polyethylene-vinyl acetate and uniformly disperse the graphene nanosheets, forming a uniformly mixed solution of polyethylene-vinyl acetate and graphene nanosheets with mass fractions of 20wt.% and 25wt.%, respectively. After standing for 2h to remove bubbles, pour the solution into a custom mold with a depth of 0.5mm and a height of 10cm×10cm. Then dry at room temperature to obtain a 0.15mm microwave absorbing layer C.

[0086] (4) The conductive polyester fabric A, conductive metal PET film B, and wave-absorbing layer C of the specified size obtained in steps (1), (2), and (3) are combined in the order CBCAC, and then high-temperature pressure encapsulation is performed to obtain a modular full-spectrum electromagnetic shielding flexible fabric. The encapsulation temperature at both ends is 150℃, the encapsulation pressure is 20Mpa, and the encapsulation time is 10min.

[0087] The electromagnetic shielding effectiveness of Example 2 was tested using the window method, and the shielding effectiveness in each frequency band is shown in Table 2. It has excellent full-spectrum electromagnetic shielding performance.

[0088] Table 2 Electromagnetic shielding effectiveness at different frequency bands

[0089] Frequency band (Hz) 14K 100K 200K 450M 950M 3G 6G 10G 18G Performance (-dB) 13 27 35 55 50 49 45 45 44

[0090] Example 3

[0091] Example 3 modifies the surface metal thickness of the polymer film in Example 1.

[0092] (1) Place the 10cm×10cm polyester fabric with a thickness of 0.1mm to be treated in the magnetron sputtering system, adjust the sputtering time to 20min, the sputtering power to 100W, and the metal target to nickel (Ni) before surface metal deposition to obtain a conductive polyester fabric A with a surface metal thickness of 0.5μm.

[0093] (2) Place a 10cm×10cm PET film with a thickness of 0.1mm into a vacuum coating system, adjust the vacuum coating time to 5min, the vacuum coating power to 200W, and the metal target to aluminum (Al) before surface metal coating to obtain a conductive metal PET film B with a surface metal film thickness of 0.15μm.

[0094] (3) Mix 4g of polyethylene-vinyl acetate (EVA) and 5g of graphene nanosheets with dichloromethane to form a 20g mixed solution. Stir for 3h to completely dissolve the polyethylene-vinyl acetate and uniformly disperse the graphene nanosheets, forming a uniformly mixed solution of polyethylene-vinyl acetate and graphene nanosheets with mass fractions of 20wt.% and 25wt.%, respectively. After standing for 2h to remove bubbles, pour the solution into a custom mold with a depth of 0.5mm and a height of 10cm×10cm. Then dry at room temperature to obtain a 0.15mm microwave absorbing layer C.

[0095] (4) The conductive polyester fabric A, conductive metal PET film B, and wave-absorbing layer C of the specified size obtained in steps (1), (2), and (3) are combined in the order CBCAC, and then high-temperature pressure encapsulation is performed to obtain a modular full-spectrum electromagnetic shielding flexible fabric. The encapsulation temperature at both ends is 150℃, the encapsulation pressure is 20Mpa, and the encapsulation time is 10min.

[0096] After testing the electromagnetic shielding effectiveness using the window method, the shielding effectiveness of Example 3 in each frequency band is shown in Table 3, demonstrating excellent full-spectrum electromagnetic shielding performance.

[0097] Table 3 Electromagnetic shielding effectiveness at different frequency bands

[0098] Frequency band (Hz) 14K 100K 200K 450M 950M 3G 6G 10G 18G Performance (-dB) 17 32 39 63 60 55 54 54 53

[0099] Example 4

[0100] Example 4 modifies the thickness of the absorbing layer in Example 1.

[0101] (1) Place the 10cm×10cm polyester fabric with a thickness of 0.1mm to be treated in the magnetron sputtering system, adjust the sputtering time to 20min, the sputtering power to 100W, and the metal target to nickel (Ni) before surface metal deposition to obtain a conductive polyester fabric A with a surface metal thickness of 0.5μm.

[0102] (2) Place a 10cm×10cm PET film with a thickness of 0.1mm into a vacuum coating system, adjust the vacuum coating time to 10min, the vacuum coating power to 200W, and the metal target to aluminum (Al) before performing surface metal coating to obtain a conductive metal PET film B with a surface metal film thickness of 0.3μm.

[0103] (3) Mix 2g of polyethylene-vinyl acetate (EVA) and 2.5g of graphene nanosheets with dichloromethane to form a 10g mixed solution. Stir for 3h to completely dissolve the polyethylene-vinyl acetate and uniformly disperse the graphene nanosheets to form a uniformly mixed solution of polyethylene-vinyl acetate and graphene nanosheets with mass fractions of 20wt.% and 25wt.%, respectively. After standing for 2h to remove bubbles, pour the solution into a custom mold with a depth of 0.5mm and a height of 10cm×10cm. Then dry at room temperature to obtain a 0.3mm microwave absorbing layer C.

[0104] (4) The conductive polyester fabric A, conductive metal PET film B, and wave-absorbing layer C of the specified size obtained in steps (1), (2), and (3) are combined in the order CBCAC, and then high-temperature pressure encapsulation is performed to obtain a modular full-spectrum electromagnetic shielding flexible fabric. The encapsulation temperature at both ends is 150℃, the encapsulation pressure is 20Mpa, and the encapsulation time is 10min.

[0105] (5) After testing the electromagnetic shielding effectiveness using the window method, the shielding effectiveness of Example 4 in each frequency band is shown in Table 4, which shows that it has excellent full-spectrum electromagnetic shielding performance.

[0106] Table 4 Electromagnetic shielding effectiveness at different frequency bands

[0107] Frequency band (Hz) 14K 100K 200K 450M 950M 3G 6G 10G 18G Performance (-dB) 21 37 46 73 73 69 68 67 66

[0108] Example 5

[0109] Example 5 changes the order of the electromagnetic shielding modules A, B, and C in Example 1.

[0110] (1) Place the 10cm×10cm polyester fabric with a thickness of 0.1mm to be treated in the magnetron sputtering system, adjust the sputtering time to 20min, the sputtering power to 100W, and the metal target to nickel (Ni) before surface metal deposition to obtain a conductive polyester fabric A with a surface metal thickness of 0.5μm.

[0111] (2) Place a 10cm×10cm PET film with a thickness of 0.1mm into a vacuum coating system, adjust the vacuum coating time to 10min, the vacuum coating power to 200W, and the metal target to aluminum (Al) before performing surface metal coating to obtain a conductive metal PET film B with a surface metal film thickness of 0.3μm.

[0112] (3) Mix 4g of polyethylene-vinyl acetate (EVA) and 5g of graphene nanosheets with dichloromethane to form a 20g mixed solution. Stir for 3h to completely dissolve the polyethylene-vinyl acetate and uniformly disperse the graphene nanosheets, forming a uniformly mixed solution of polyethylene-vinyl acetate and graphene nanosheets with mass fractions of 20wt.% and 25wt.%, respectively. After standing for 2h to remove bubbles, pour the solution into a custom mold with a depth of 0.5mm and a height of 10cm×10cm. Then dry at room temperature to obtain a 0.15mm microwave absorbing layer C.

[0113] (4) The conductive polyester fabric A, conductive metal PET film B, and wave-absorbing layer C of the specified size obtained in steps (1), (2), and (3) are combined in the order ACBCA, and then high-temperature pressure encapsulation is performed to obtain a modular full-spectrum electromagnetic shielding flexible fabric. The encapsulation temperature at both ends is 150℃, the encapsulation pressure is 20MPa, and the encapsulation time is 10min.

[0114] After testing the electromagnetic shielding effectiveness using the window method, the shielding effectiveness of Example 5 in each frequency band is shown in Table 5, demonstrating excellent full-spectrum electromagnetic shielding performance.

[0115] Table 5 Electromagnetic shielding effectiveness at different frequency bands

[0116] Frequency band (Hz) 14K 100K 200K 450M 950M 3G 6G 10G 18G Performance (-dB) 7 18 25 38 39 38 36 36 35

[0117] Example 6

[0118] Example 6 changes the order of the electromagnetic shielding modules A, B, and C in Example 1.

[0119] (1) Place the polyester fabric with a thickness of 0.1 mm and a size of 10 cm × 10 cm into the magnetron sputtering system, adjust the sputtering time to 10 min, the sputtering power to 100 W, and the metal target to nickel (Ni) before surface metal deposition to obtain a conductive polyester fabric A with a surface metal thickness of 0.3 μm.

[0120] (2) Place a 10cm×10cm PET film with a thickness of 0.1mm into a vacuum coating system, adjust the vacuum coating time to 10min, the vacuum coating power to 200W, and the metal target to aluminum (Al) before performing surface metal coating to obtain a conductive metal PET film B with a surface metal film thickness of 0.3μm.

[0121] (3) Mix 4g of polyethylene-vinyl acetate (EVA) and 5g of graphene nanosheets with dichloromethane to form a 20g mixed solution. Stir for 3h to completely dissolve the polyethylene-vinyl acetate and uniformly disperse the graphene nanosheets, forming a uniformly mixed solution of polyethylene-vinyl acetate and graphene nanosheets with mass fractions of 20wt.% and 25wt.%, respectively. After standing for 2h to remove bubbles, pour the solution into a custom mold with a depth of 0.5mm and a height of 10cm×10cm. Then dry at room temperature to obtain a 0.15mm microwave absorbing layer C.

[0122] (4) The conductive polyester fabric A, conductive metal PET film B, and wave-absorbing layer C of the specified size obtained in steps (1), (2), and (3) are combined in the order BCACB, and then high-temperature pressure encapsulation is performed to obtain a modular full-spectrum electromagnetic shielding flexible fabric. The encapsulation temperature at both ends is 150℃, the encapsulation pressure is 20MPa, and the encapsulation time is 10min.

[0123] After testing the electromagnetic shielding effectiveness using the window method, the shielding effectiveness of Example 6 in each frequency band is shown in Table 6, demonstrating excellent full-spectrum electromagnetic shielding performance.

[0124] Table 6 Electromagnetic shielding effectiveness at different frequency bands

[0125] Frequency band (Hz) 14K 100K 200K 450M 950M 3G 6G 10G 18G Performance (-dB) 6 18 25 36 35 33 31 31 30

[0126] Example 7

[0127] Example 7 changes the order of the electromagnetic shielding modules A, B, and C in Example 1.

[0128] (1) Place the polyester fabric with a thickness of 0.1 mm and a size of 10 cm × 10 cm into the magnetron sputtering system, adjust the sputtering time to 10 min, the sputtering power to 100 W, and the metal target to nickel (Ni) before surface metal deposition to obtain a conductive polyester fabric A with a surface metal thickness of 0.3 μm.

[0129] (2) Place a 10cm×10cm PET film with a thickness of 0.1mm into a vacuum coating system, adjust the vacuum coating time to 10min, the vacuum coating power to 200W, and the metal target to aluminum (Al) before performing surface metal coating to obtain a conductive metal PET film B with a surface metal film thickness of 0.3μm.

[0130] (3) Mix 4g of polyethylene-vinyl acetate (EVA) and 5g of graphene nanosheets with dichloromethane to form a 20g mixed solution. Stir for 3h to completely dissolve the polyethylene-vinyl acetate and uniformly disperse the graphene nanosheets, forming a uniformly mixed solution of polyethylene-vinyl acetate and graphene nanosheets with mass fractions of 20wt.% and 25wt.%, respectively. After standing for 2h to remove bubbles, pour the solution into a custom mold with a depth of 0.5mm and a height of 10cm×10cm. Then dry at room temperature to obtain a 0.15mm microwave absorbing layer C.

[0131] (4) The conductive polyester fabric A, conductive metal PET film B, and wave-absorbing layer C of the specified size obtained in steps (1), (2), and (3) are combined in the order ACBCB, and then high-temperature pressure encapsulation is performed to obtain a modular full-spectrum electromagnetic shielding flexible fabric. The encapsulation temperature at both ends is 150℃, the encapsulation pressure is 20MPa, and the encapsulation time is 10min.

[0132] (5) After testing the electromagnetic shielding effectiveness using the window method, the shielding effectiveness of Example (7) in each frequency band is shown in Table 7, which shows that it has excellent full-spectrum electromagnetic shielding performance.

[0133] Table 7 Electromagnetic shielding effectiveness at different frequency bands

[0134] Frequency band (Hz) 14K 100K 200K 450M 950M 3G 6G 10G 18G Performance (-dB) 8 19 26 38 38 35 34 33 32

[0135] Example 8

[0136] Example 8 changes the order of the electromagnetic shielding modules A, B, and C in Example 1.

[0137] (1) Place the polyester fabric with a thickness of 0.1 mm and a size of 10 cm × 10 cm into the magnetron sputtering system, adjust the sputtering time to 10 min, the sputtering power to 100 W, and the metal target to nickel (Ni) before surface metal deposition to obtain a conductive polyester fabric A with a surface metal thickness of 0.3 μm.

[0138] (2) Place a 10cm×10cm PET film with a thickness of 0.1mm into a vacuum coating system, adjust the vacuum coating time to 10min, the vacuum coating power to 200W, and the metal target to aluminum (Al) before performing surface metal coating to obtain a conductive metal PET film B with a surface metal film thickness of 0.3μm.

[0139] (3) Mix 4g of polyethylene-vinyl acetate (EVA) and 5g of graphene nanosheets with dichloromethane to form a 20g mixed solution. Stir for 3h to completely dissolve the polyethylene-vinyl acetate and uniformly disperse the graphene nanosheets, forming a uniformly mixed solution of polyethylene-vinyl acetate and graphene nanosheets with mass fractions of 20wt.% and 25wt.%, respectively. After standing for 2h to remove bubbles, pour the solution into a custom mold with a depth of 0.5mm and a height of 10cm×10cm. Then dry at room temperature to obtain a 0.15mm microwave absorbing layer C.

[0140] (4) The conductive polyester fabric A, conductive metal PET film B, and wave-absorbing layer C of the specified size obtained in steps (1), (2), and (3) are combined in the order BCACA, and then high-temperature pressure encapsulation is performed to obtain a modular full-spectrum electromagnetic shielding flexible fabric. The encapsulation temperature at both ends is 150℃, the encapsulation pressure is 20Mpa, and the encapsulation time is 10min.

[0141] The electromagnetic shielding effectiveness of Example 8 was tested using the window method, and the shielding effectiveness in each frequency band is shown in Table 8. It has excellent full-spectrum electromagnetic shielding performance.

[0142] Table 8 Electromagnetic shielding effectiveness at different frequency bands

[0143]

[0144]

[0145] Example 9

[0146] Example 9 changes the order of the electromagnetic shielding modules A, B, and C in Example 1.

[0147] (1) Place the polyester fabric with a thickness of 0.1 mm and a size of 10 cm × 10 cm into the magnetron sputtering system, adjust the sputtering time to 10 min, the sputtering power to 100 W, and the metal target to nickel (Ni) before surface metal deposition to obtain a conductive polyester fabric A with a surface metal thickness of 0.3 μm.

[0148] (2) Place a 10cm×10cm PET film with a thickness of 0.1mm into a vacuum coating system, adjust the vacuum coating time to 10min, the vacuum coating power to 200W, and the metal target to aluminum (Al) before performing surface metal coating to obtain a conductive metal PET film B with a surface metal film thickness of 0.3μm.

[0149] (3) Mix 4g of polyethylene-vinyl acetate (EVA) and 5g of graphene nanosheets with dichloromethane to form a 20g mixed solution. Stir for 3h to completely dissolve the polyethylene-vinyl acetate and uniformly disperse the graphene nanosheets, forming a uniformly mixed solution of polyethylene-vinyl acetate and graphene nanosheets with mass fractions of 20wt.% and 25wt.%, respectively. After standing for 2h to remove bubbles, pour the solution into a custom mold with a depth of 0.5mm and a height of 10cm×10cm. Then dry at room temperature to obtain a 0.15mm microwave absorbing layer C.

[0150] (4) The conductive polyester fabric A, conductive metal PET film B, and wave-absorbing layer C of the specified size obtained in steps (1), (2), and (3) are combined in the order CBCA, and then high-temperature pressure encapsulation is performed to obtain a modular full-spectrum electromagnetic shielding flexible fabric. The encapsulation temperature at both ends is 150℃, the encapsulation pressure is 20Mpa, and the encapsulation time is 10min.

[0151] After testing the electromagnetic shielding effectiveness using the window method, the shielding effectiveness of Example 9 in each frequency band is shown in Table 9, demonstrating excellent full-spectrum electromagnetic shielding performance.

[0152] Table 9 Electromagnetic shielding effectiveness at different frequency bands

[0153] Frequency band (Hz) 14K 100K 200K 450M 950M 3G 6G 10G 18G Performance (-dB) 5 11 19 29 28 25 25 24 22

[0154] Example 10

[0155] Example 10 changed the order of the electromagnetic shielding modules A, B, and C in Example 1.

[0156] (1) Place the polyester fabric with a thickness of 0.1 mm and a size of 10 cm × 10 cm into the magnetron sputtering system, adjust the sputtering time to 10 min, the sputtering power to 100 W, and the metal target to nickel (Ni) before surface metal deposition to obtain a conductive polyester fabric A with a surface metal thickness of 0.3 μm.

[0157] (2) Place a 10cm×10cm PET film with a thickness of 0.1mm into a vacuum coating system, adjust the vacuum coating time to 10min, the vacuum coating power to 200W, and the metal target to aluminum (Al) before performing surface metal coating to obtain a conductive metal PET film B with a surface metal film thickness of 0.3μm.

[0158] (3) Mix 4g of polyethylene-vinyl acetate (EVA) and 5g of graphene nanosheets with dichloromethane to form a 20g mixed solution. Stir for 3h to completely dissolve the polyethylene-vinyl acetate and uniformly disperse the graphene nanosheets, forming a uniformly mixed solution of polyethylene-vinyl acetate and graphene nanosheets with mass fractions of 20wt.% and 25wt.%, respectively. After standing for 2h to remove bubbles, pour the solution into a custom mold with a depth of 0.5mm and a height of 10cm×10cm. Then dry at room temperature to obtain a 0.15mm microwave absorbing layer C.

[0159] (4) The conductive polyester fabric A, conductive metal PET film B, and wave-absorbing layer C of the specified size obtained in steps (1), (2), and (3) are combined in the order CACB, and then high-temperature pressure encapsulation is performed to obtain a modular full-spectrum electromagnetic shielding flexible fabric. The encapsulation temperature at both ends is 150℃, the encapsulation pressure is 20Mpa, and the encapsulation time is 10min.

[0160] The electromagnetic shielding effectiveness of Example 10 was tested using the window method, and the shielding effectiveness in each frequency band is shown in Table 10. It has excellent full-spectrum electromagnetic shielding performance.

[0161] Table 10 Electromagnetic shielding effectiveness at different frequency bands

[0162] Frequency band (Hz) 14K 100K 200K 450M 950M 3G 6G 10G 18G Performance (-dB) 6 12 21 30 29 26 26 25 24

[0163] Comparative Example 1

[0164] Comparative Example 1 is a comparative example of Example 1, but it lacks the magnetron sputtering deposition of metal on the surface of the polyester fabric.

[0165] (1) The 10cm×10cm polyester fabric that has not undergone the magnetron sputtering metal deposition process is denoted as A*.

[0166] (2) Place a 10cm×10cm PET film with a thickness of 0.1mm into a vacuum coating system, adjust the vacuum coating time to 10min, the vacuum coating power to 200W, and the metal target to aluminum (Al) before performing surface metal coating to obtain a conductive metal PET film B with a surface metal film thickness of 0.3μm.

[0167] (3) Mix 4g of polyethylene-vinyl acetate (EVA) and 5g of graphene nanosheets with dichloromethane to form a 20g mixed solution. Stir for 3h to completely dissolve the polyethylene-vinyl acetate and uniformly disperse the graphene nanosheets, forming a uniformly mixed solution of polyethylene-vinyl acetate and graphene nanosheets with mass fractions of 20wt.% and 25wt.%, respectively. After standing for 2h to remove bubbles, pour the solution into a custom mold with a depth of 0.5mm and a height of 10cm×10cm. Then dry at room temperature to obtain a 0.15mm microwave absorbing layer C.

[0168] (4) The conductive polyester fabric A, conductive metal PET film B, and wave-absorbing layer CBCA*C of the specified size obtained in steps (1), (2), and (3) are combined in the order of , and then high-temperature pressure encapsulation is performed to obtain modular full-spectrum electromagnetic shielding flexible fabric. The encapsulation temperature at both ends is 150℃, the encapsulation pressure is 20Mpa, and the encapsulation time is 10min.

[0169] The electromagnetic shielding effectiveness of Comparative Example 1 in each frequency band was obtained after testing with the window method. Table 11 shows that it has excellent full-spectrum electromagnetic shielding performance.

[0170] Table 11 Electromagnetic shielding effectiveness at different frequency bands

[0171] Frequency band (Hz) 14K 100K 200K 450M 950M 3G 6G 10G 18G Performance (-dB) 4 7 15 23 24 23 22 21 21

[0172] Comparative Example 2

[0173] Comparative Example 1 is a comparative example of Example 1, but it lacks the vacuum deposition of metal on the surface of the PET film.

[0174] (1) Place the polyester fabric with a thickness of 0.1 mm and a size of 10 cm × 10 cm into the magnetron sputtering system, adjust the sputtering time to 10 min, the sputtering power to 100 W, and the metal target to nickel (Ni) before surface metal deposition to obtain a conductive polyester fabric A with a surface metal thickness of 0.3 μm.

[0175] (2) The 10cm×10cm PET film that has not undergone the vacuum metal deposition process is denoted as B*.

[0176] (3) Mix 4g of polyethylene-vinyl acetate (EVA) and 5g of graphene nanosheets with dichloromethane to form a 20g mixed solution. Stir for 3h to completely dissolve the polyethylene-vinyl acetate and uniformly disperse the graphene nanosheets, forming a uniformly mixed solution of polyethylene-vinyl acetate and graphene nanosheets with mass fractions of 20wt.% and 25wt.%, respectively. After standing for 2h to remove bubbles, pour the solution into a custom mold with a depth of 0.5mm and a height of 10cm×10cm. Then dry at room temperature to obtain a 0.15mm microwave absorbing layer C.

[0177] (4) The conductive polyester fabric A, conductive metal PET film B, and wave-absorbing layer CB*CAC of the specified size obtained in steps (1), (2), and (3) are combined in the order of , and then high-temperature pressure encapsulation is performed to obtain modular full-spectrum electromagnetic shielding flexible fabric. The encapsulation temperature at both ends is 150℃, the encapsulation pressure is 20Mpa, and the encapsulation time is 10min.

[0178] The electromagnetic shielding effectiveness of Comparative Example 2 was tested using the window method, and the shielding effectiveness in each frequency band is shown in Table 12. It has excellent full-spectrum electromagnetic shielding performance.

[0179] Table 12 Electromagnetic shielding effectiveness at different frequency bands

[0180] Frequency band (Hz) 14K 100K 200K 450M 950M 3G 6G 10G 18G Performance (-dB) 3 6 16 22 23 22 22 21 20

[0181] Comparative Example 3

[0182] Comparative Example 3 is a comparison with Example 1, but it lacks the high-temperature thermo-pressing encapsulation process.

[0183] (1) Place the polyester fabric with a thickness of 0.1 mm and a size of 10 cm × 10 cm into the magnetron sputtering system, adjust the sputtering time to 10 min, the sputtering power to 100 W, and the metal target to nickel (Ni) before surface metal deposition to obtain a conductive polyester fabric A with a surface metal thickness of 0.3 μm.

[0184] (2) Place a 10cm×10cm PET film with a thickness of 0.1mm into a vacuum coating system, adjust the vacuum coating time to 10min, the vacuum coating power to 200W, and the metal target to aluminum (Al) before performing surface metal coating to obtain a conductive metal PET film B with a surface metal film thickness of 0.3μm.

[0185] (3) Mix 4g of polyethylene-vinyl acetate (EVA) and 5g of graphene nanosheets with dichloromethane to form a 20g mixed solution. Stir for 3h to completely dissolve the polyethylene-vinyl acetate and uniformly disperse the graphene nanosheets, forming a uniformly mixed solution of polyethylene-vinyl acetate and graphene nanosheets with mass fractions of 20wt.% and 25wt.%, respectively. After standing for 2h to remove bubbles, pour the solution into a custom mold with a depth of 0.5mm and a height of 10cm×10cm. Then dry at room temperature to obtain a 0.15mm microwave absorbing layer C.

[0186] After testing the electromagnetic shielding effectiveness using the window method, the shielding effectiveness of electromagnetic shielding modules A, B, and C in Comparative Example 3 in each frequency band is shown in Table 13, demonstrating excellent full-spectrum electromagnetic shielding performance.

[0187] Table 13 Electromagnetic shielding effectiveness at different frequency bands

[0188] Frequency band (Hz) 14K 100K 200K 450M 950M 3G 6G 10G 18G Module A (-dB) 2 4 7 12 13 14 13 13 12 Module B (-dB) 4 7 10 15 18 18 16 15 14 Module C (-dB) 1 2 2 3 4 12 12 10 10

[0189] Based on the various embodiments and comparative examples, the present invention is based on a specific arrangement and combination of multiple modules such as conductive fabric A, conductive film B, and absorbing layer C. The synergy between these multiple modules can achieve better full-spectrum electromagnetic shielding performance in low, medium and high frequency bands.

[0190] The embodiments provided above are not intended to limit the scope of the invention, nor are the described steps intended to limit the order of execution. Any obvious modifications made to the invention by those skilled in the art based on existing common knowledge also fall within the scope of protection defined by the claims.

Claims

1. A method for preparing a modular full-spectrum electromagnetic shielding flexible composite fabric, characterized in that, Includes the following steps: (1) Preparation of conductive fabric A A flexible conductive fabric A is obtained by depositing metal on the surface of a fabric using a magnetron sputtering system; the thickness of the fabric is 0.05 mm-0.1 mm; and the surface metal thickness of the conductive fabric A is 0.3-0.5 μm. (2) Preparation of conductive thin film B A high-toughness conductive film B is obtained by performing metal deposition treatment on the surface of a polymer film using vacuum deposition; the thickness of the polymer film is 0.05 mm-0.1 mm; and the surface metal thickness of the conductive film B is 0.15-0.3 μm. (3) Preparation of absorbing layer C After mixing and dissolving carbon-based microwave absorbing material, polymer, and solvent, the mixture is poured into a specified mold for curing to obtain microwave absorbing layer C; the thickness of microwave absorbing layer C is 0.15 mm-0.3 mm. (4) Preparation of full-spectrum electromagnetic shielding fabric The conductive fabric A, conductive film B, and absorbing layer C obtained in steps (1), (2), and (3) are arranged, combined, and encapsulated to obtain the modular full-spectrum electromagnetic shielding flexible composite fabric; the encapsulation temperature is 150℃, the encapsulation pressure is 20MPa, and the encapsulation time is 10min. The conductive fabric A, conductive film B, and absorbing layer C are arranged in the order CBCAC.

2. The method according to claim 1, characterized in that, The fabric described in step (1) is a blend of one or more fibers, including nylon, polyester, acrylic, spandex, vinylon, polypropylene, and chlorofiber.

3. The method according to claim 1, characterized in that, The target material for magnetron sputtering in step (1) is one or several alloys of nickel, aluminum, copper, and silver.

4. The method according to claim 1, characterized in that, The sputtering time for magnetron sputtering in step (1) is 10-30 min.

5. The method according to claim 1, characterized in that, The sputtering power of the magnetron sputtering in step (1) is 50-150 W.

6. The method according to claim 1, characterized in that, The polymer film mentioned in step (2) is one or more of polyamide, polysulfone, polyvinylidene fluoride, polypropylene, and polyester.

7. The method according to claim 1, characterized in that, The target material for vacuum coating in step (2) is one or several alloys of nickel, aluminum, copper, and silver.

8. The method according to claim 1, characterized in that, The vacuum coating time in step (2) is 5-20 minutes.

9. The method according to claim 1, characterized in that, The power of vacuum coating in step (2) is 100-300W.

10. The method according to claim 1, characterized in that, The carbon-based microwave absorbing material mentioned in step (3) is one or more of the following: carbon nanotubes and their derivatives, graphene and its derivatives, carbon black and its derivatives, Mxene and its derivatives, carbon quantum dots and their derivatives, and fullerene and its derivatives.

11. The method according to claim 1, characterized in that, The polymer mentioned in step (3) is one or more of polypropylene, polyethylene, polyvinyl chloride, polyester, polyvinylidene fluoride, polytetrachloroethylene, and polyethylene-vinyl acetate.

12. The method according to claim 1, characterized in that, The solvent mentioned in step (3) is one or more of N,N-dimethylformamide, N,N-dimethylacetamide, acetone, chloroform, dichloromethane, and tetrahydrofuran.

13. The method according to claim 1, characterized in that, The polymer in step (3) has a mass fraction of 10-30 wt.% in the solvent.

14. The method according to claim 1, characterized in that, The concentration of the carbon-based microwave absorbing material in step (3) is 10 wt.%-50 wt.%.

15. A modular full-spectrum electromagnetic shielding flexible composite fabric prepared by the method according to any one of claims 1-14.

16. The application of the modular full-spectrum electromagnetic shielding flexible composite fabric of claim 15 in the fabrication of electronic components.

17. The application of the modular full-spectrum electromagnetic shielding flexible composite fabric as described in claim 15 in the military field.