A non-metallic electromagnetic shielding sheath and its preparation method

Abstract

The present invention belongs to the field of electromagnetic protection technology, and specifically relates to a non-metallic electromagnetic shielding sheath and a preparation method thereof. The preparation method comprises the following steps: adding conductive particles as a mixed slurry A to a polymer solution, adding magnetic particles as a mixed slurry B to the polymer solution, and coating the mixed slurries A and B on the two sides of carbon fiber paper respectively to prepare an electromagnetic shielding film; then stacking the carbon fiber, aramid fiber and electromagnetic shielding film layer by layer, bonding them by mechanical pressing, and shaping them into a roll to prepare a shielding sheath. The electromagnetic shielding sheath designed by the present invention not only has good shielding effectiveness, but also has the characteristics of high flexibility and light weight. The three-layer composite structure can effectively resist external electromagnetic radiation, protect the equipment inside the wire or cable from interference, and prevent the signal inside the wire or cable from leaking, thereby ensuring the stability and safety of signal transmission.

Description

Technical Field

[0001] The present invention belongs to the technical field of electromagnetic protection, and in particular relates to a non-metallic electromagnetic shielding sheath and a preparation method thereof. Background Art

[0002] With the rapid development of modern electronic devices, electromagnetic compatibility (EMC) issues are becoming increasingly prominent. The impact of electromagnetic interference (EMI) on electronic equipment is increasing, and effectively reducing and managing this interference has become a critical issue that the engineering community urgently needs to address. In electronic devices, data transmission cables serve as a critical path for information transmission, so the design and material selection of their electromagnetic shielding sheaths are particularly important.

[0003] Significant progress has been made in the research and application of electromagnetic shielding sheaths both domestically and internationally. Research institutions and companies in foreign countries, such as those in the United States and Europe, have long been committed to developing efficient shielding technologies to cope with increasingly complex electromagnetic environments. They focus on systematic optimization of every aspect, from material selection and structural design to manufacturing processes, aiming to enhance shielding effectiveness and ensure the stability and reliability of electronic equipment in various environments. Currently, mainstream shielding sheaths abroad are mostly made of metal materials, which have disadvantages such as high density and susceptibility to corrosion. In contrast, research on electromagnetic shielding sheaths in China started later, and the main sheath products are mainly insulation. However, domestic awareness and investment in addressing electromagnetic interference issues are gradually increasing, laying the foundation for technological innovation and enhanced market competitiveness.

[0004] With the development and popularization of 5G mobile communications, electronic devices are moving towards flexibility, lightness and portability. In order to prevent electromagnetic interference from damaging them, electromagnetic shielding materials are needed for protection. Traditional metal shielding materials can no longer meet modern needs due to their high density, poor corrosion resistance, poor flexibility and difficulty in processing. Therefore, polymer composites doped with conductive fillers have become the focus of research due to their lightness and high flexibility. However, due to the high percolation threshold of conductive polymer composites, a high content of fillers is usually required to achieve high EMI shielding performance, which seriously affects flexibility, mechanical properties and processability. Therefore, the development of excellent electromagnetic interference shielding materials at lower filler loadings remains a huge challenge.

[0005] As a new type of electromagnetic shielding material, non-metallic electromagnetic shielding sheaths hold broad application prospects in the field of electromagnetic protection. Materials such as conductive polymers and carbon fibers, with their unique electromagnetic shielding effectiveness and lightweight characteristics, will drive their development in this field. Designing non-metallic electromagnetic shielding sheaths that resist external electromagnetic interference and reduce electromagnetic radiation, thereby ensuring stable and secure signal transmission and providing excellent electromagnetic protection for electronic equipment, will have significant implications for the electronics industry. Summary of the Invention

[0006] One of the purposes of the present invention is to provide a method for preparing a non-metallic electromagnetic shielding sheath. The method is simple to operate, and the shielding sheath produced has the functions of being lightweight and scratch-resistant, while also having excellent electromagnetic shielding performance.

[0007] To achieve the above object, the present invention adopts the following technical solution: a method for preparing a non-metallic electromagnetic shielding sheath, comprising the following steps:

[0008] S1, cutting the carbon fiber and aramid fiber into appropriate sizes, and pretreating the cut carbon fiber to obtain pretreated carbon fiber;

[0009] S2. Mix the polymer and the additive in a mass ratio of 100:(0.1-1.0), and stir until uniformly dispersed to obtain a polymer solution;

[0010] Take 90-99 parts by mass of the polymer solution, add 1-10 parts by mass of conductive particles thereto, and stir until uniformly dispersed to prepare 100 parts by mass of mixed slurry A;

[0011] Take 80-95 parts by mass of the polymer solution, add 5-20 parts by mass of magnetic particles thereto, and stir until uniformly dispersed to prepare 100 parts by mass of mixed slurry B;

[0012] S3, coating mixed slurry A on one side of the carbon fiber paper, and coating mixed slurry B on the other side of the carbon fiber paper, with a coating thickness of 100-1000 μm, and drying to obtain an electromagnetic shielding film;

[0013] S4, laminating the aramid fibers cut in step S1, the pretreated carbon fibers, and the electromagnetic shielding film obtained in step S3, pressing and curing them to obtain a shielding sheath;

[0014] There is no particular order for steps S1 and S2.

[0015] Further improvement of the preparation method of non-metallic electromagnetic shielding sheath:

[0016] Preferably, the carbon fiber is pretreated in step S1 by placing it in an oven at 120-180° C. for 1-2 hours, or soaking it in ethanol for 0.5-1 hour and then drying it.

[0017] Preferably, the polymer is one or a combination of two or more of polyvinyl alcohol, polyacrylamide, polyurethane, polyvinylidene fluoride and polydimethylsiloxane, and the mixing and stirring time of the polymer and the auxiliary agent is 10 to 60 minutes.

[0018] Preferably, the surface density of the carbon fiber paper is 10g / m 2 , 15g / m 2 , 20g / m2 or 30g / m 2 The manufacturer is Jiangsu Zeyusen Carbon Fiber Technology Co., Ltd.

[0019] Preferably, the process parameters for pressing in step S4 are: pressure 0.1-2.0 MPa, temperature 30-80° C., and time 10-60 min.

[0020] Preferably, the auxiliary agent is one or a combination of two or more of a thickener, a defoamer, a dispersant and a leveling agent.

[0021] Preferably, the conductive particles are one or a combination of two or more of graphene, carbon nanotubes and carbon black.

[0022] Preferably, the magnetic particles are NiCo nano-alloy particles or Fe3O4 nano-particles.

[0023] Preferably, in step S2, magnetic stirring is used to stir until the mixture is uniformly dispersed, with a stirring speed of 100-800 r / min and a stirring time of 30-60 min.

[0024] A second object of the present invention is to provide a non-metallic electromagnetic shielding sheath produced by the method for producing the non-metallic electromagnetic shielding sheath described in any one of the above.

[0025] The beneficial effects of the present invention compared to the prior art are:

[0026] The present invention provides a method for preparing a non-metallic electromagnetic shielding sheath. The method first selects highly wear-resistant aramid fiber as the outer layer of the sheath, ensuring the sheath's scratch resistance. Pretreated, debonded carbon fiber with high conductivity is selected as the sheath's shielding layer. Carbon fiber paper is used as a reinforcing material. A polymer solution containing conductive particles and a polymer solution containing magnetic particles are coated on the upper and lower surfaces of the carbon fiber paper using a simple coating method. The resulting electromagnetic shielding film serves as the absorption layer, resolving the shortcoming of polymer composite materials, which rely on high filler content for high shielding performance. The aramid fiber, pretreated carbon fiber, and electromagnetic shielding film are then laminated and solidified into a single body. The structural design of the three, through a simple mechanical pressing method, achieves high shielding performance and flexibility at a low filler content.

[0027] 2) The non-metallic electromagnetic shielding sheath prepared by the present invention includes a highly wear-resistant aramid fiber layer (AF), a highly conductive carbon fiber layer (CF), and an electromagnetic shielding film layer with absorption capacity. The electromagnetic shielding film is based on carbon fiber paper (CFP), and a high magnetic permeability layer and a high electrical conductivity layer respectively bonded to the upper surface and lower surface of the carbon fiber paper. The present invention provides an electromagnetic shielding material with a "3+3" layer structure. Since the electrical conductivity and magnetic permeability of materials between different layers are different, electromagnetic waves will undergo a process of "absorption-reflection-reabsorption" after entering the material, thereby achieving high shielding effectiveness while reducing the secondary reflection of electromagnetic waves and avoiding secondary pollution. It has the following specific advantages:

[0028] Electromagnetic shielding function. Generally speaking, an electromagnetic shielding material with a shielding effectiveness between 30dB and 60dB can meet the requirements of general industrial electronic equipment, while a shielding effectiveness between 60dB and 90dB can meet the requirements of precision instruments and military equipment. If the shielding effectiveness reaches 60dB or above, the material can be said to have good electromagnetic shielding effectiveness. The non-metallic electromagnetic shielding sheath of the present invention has an electromagnetic shielding effectiveness of over 70dB in the frequency range of 8.2GHz-12.4GHz (X-band).

[0029] Flexibility. This invention utilizes a structural design to produce a three-layer electromagnetic shielding material, all made of flexible materials. The resulting electromagnetic shielding sheath exhibits excellent flexibility, making it suitable for addressing signal crosstalk between cables and harnesses. Compared to other materials, it is more adaptable to different shapes and more convenient for practical applications.

[0030] Lightweight material. Compared with traditional metallic electromagnetic shielding materials, the non-metallic electromagnetic shielding sheath of the present invention is made of non-metallic materials, avoiding disadvantages such as high material density and susceptibility to corrosion. Compared with common polymer electromagnetic shielding materials, by introducing carbon paper, the present invention achieves high shielding effectiveness at a lower filler mass fraction, avoiding the problem of excessive filler leading to reduced mechanical properties. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 is a SEM image of the electromagnetic shielding film prepared in Example 3 of the present invention;

[0032] Figure 2 It is a shielding performance diagram of Comparative Example 1 and Examples 1-4 in the present invention. DETAILED DESCRIPTION

[0033] In order to make the objectives, technical solutions and advantages of the present invention more clear, the present invention is further described in detail below in conjunction with the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0034] Comparative Example 1

[0035] This comparative example provides a method for preparing a shielding sheath, which specifically includes the following steps:

[0036] S1, cutting carbon fiber and aramid fiber into appropriate sizes, placing the cut carbon fiber in an oven at 120° C. for 1 hour for pretreatment to obtain pretreated carbon fiber;

[0037] S2. Mixing the polyurethane resin and the auxiliary agent (defoaming agent) in a mass ratio of 100:0.3, and magnetically stirring until the mixture is uniform to obtain a polymer solution;

[0038] The polymer solution was coated on the upper and lower surfaces of the carbon fiber paper with a coating thickness of 200 μm, and vacuum dried in a vacuum drying oven at 40°C for 8 hours to form an electromagnetic shielding film;

[0039] S2, laminating the aramid fibers cut in step S1, the pretreated carbon fibers, and the electromagnetic shielding film, pressing them together, and curing them to form a shielding sheath;

[0040] The total shielding effectiveness SE of the electromagnetic shielding composite material prepared from aramid fiber, carbon fiber and electromagnetic shielding film in this comparative example is tested. T It is 38.0dB.

[0041] Example 1

[0042] This embodiment provides a method for preparing a non-metallic electromagnetic shielding sheath, which specifically includes the following steps:

[0043] Step S1, cutting the carbon fiber and aramid fiber into appropriate sizes, and placing the cut carbon fiber in an oven at 120° C. for 1 hour for pretreatment to obtain pretreated carbon fiber;

[0044] Step S2, mixing the polyurethane resin and the auxiliary agent (defoaming agent) in a mass ratio of 100:0.1, and magnetically stirring until the mixture is uniformly mixed to obtain a polymer solution;

[0045] 94 parts by mass of the polymer solution were added thereto, 3 parts by mass of multi-walled carbon nanotubes and 3 parts by mass of graphene, and stirred until uniformly dispersed to obtain a mixed slurry A;

[0046] 95 parts by mass of the polymer solution were added with 5 parts by mass of magnetic ferrosoferric oxide particles, and stirred until uniformly dispersed to obtain a mixed slurry B;

[0047] Step S3: take the surface density as 15g / m 2 , carbon fiber paper manufactured by Jiangsu Zeyusen Carbon Fiber Technology Co., Ltd.; the mixed slurries A and B are coated on the upper and lower surfaces of the carbon fiber paper, respectively, with a coating thickness of 100 μm and 100 μm, respectively, and dried to form an electromagnetic shielding film;

[0048] S4. The aramid fibers cut in step S1, the pretreated carbon fibers, and the electromagnetic shielding film in step S3 are stacked layer by layer, pressed, and cured to shape. The pressing pressure is 0.5 MPa, the temperature is 40° C., and the time is 20 min to obtain a shielding sheath.

[0049] The total shielding effectiveness SE of the electromagnetic shielding composite material prepared by aramid fiber, pretreated carbon fiber and electromagnetic shielding film in this embodiment is tested. T It is 73.3dB.

[0050] Example 2

[0051] This embodiment provides a method for preparing a non-metallic electromagnetic shielding sheath, which specifically includes the following steps:

[0052] Step S1, cutting the carbon fiber and aramid fiber into appropriate sizes, and placing the cut carbon fiber in an oven at 120° C. for 1 hour for pretreatment to obtain pretreated carbon fiber;

[0053] Step S2, mixing the polyacrylamide resin and the auxiliary agent (defoaming agent) in a mass ratio of 100:0.3, and magnetically stirring until the mixture is uniform to obtain a polymer solution;

[0054] 99 parts by mass of the polymer solution were taken, 1 part by mass of carbon black was added thereto, and the mixture was stirred until uniformly dispersed to obtain a mixed slurry A;

[0055] 80 parts by mass of the polymer solution were taken, 20 parts by mass of magnetic ferrosoferric oxide particles were added thereto, and the mixture was stirred until uniformly dispersed to obtain a mixed slurry B;

[0056] Step S3: take the surface density as 20g / m 2 , carbon fiber paper manufactured by Jiangsu Zeyusen Carbon Fiber Technology Co., Ltd.; the mixed slurries A and B are coated on the upper and lower surfaces of the carbon fiber paper, respectively, with coating thicknesses of 200 μm and 500 μm, and dried to form an electromagnetic shielding film;

[0057] S4. The aramid fibers cut in step S1, the pretreated carbon fibers, and the electromagnetic shielding film in step S3 are stacked layer by layer, pressed, and cured to shape. The pressing pressure is 1.0 MPa, the temperature is 50° C., and the time is 10 minutes to obtain a shielding sheath.

[0058] The total shielding effectiveness SE of the electromagnetic shielding composite material prepared by aramid fiber, pretreated carbon fiber and electromagnetic shielding film in this embodiment is tested. T It is 78.4dB.

[0059] Example 3

[0060] This embodiment provides a method for preparing a non-metallic electromagnetic shielding sheath, which specifically includes the following steps:

[0061] Step S1, cutting the carbon fiber and aramid fiber into appropriate sizes, and placing the cut carbon fiber in an oven at 120° C. for 1 hour for pretreatment to obtain pretreated carbon fiber;

[0062] Step S2, mixing the polyvinyl alcohol resin and the auxiliary agent (dispersant) in a mass ratio of 100:0.5, and magnetically stirring until the mixture is uniformly mixed to obtain a polymer solution;

[0063] 90 parts by mass of the polymer solution were taken, 6 parts by mass of multi-walled carbon nanotubes and 4 parts by mass of graphene were added thereto, and the mixture was stirred until uniformly dispersed to obtain a mixed slurry A;

[0064] 94 parts by mass of the polymer solution were taken, and 6 parts by mass of magnetic ferrosoferric oxide particles were added thereto, and stirred until uniformly dispersed to obtain a mixed slurry B;

[0065] Step S3: take the surface density as 10g / m 2 , carbon fiber paper manufactured by Jiangsu Zeyusen Carbon Fiber Technology Co., Ltd.; the mixed slurries A and B are coated on the upper and lower surfaces of the carbon fiber paper, respectively, with a coating thickness of 500 μm and 500 μm, respectively, and dried to form an electromagnetic shielding film;

[0066] S4. The aramid fibers cut in step S1, the pretreated carbon fibers, and the electromagnetic shielding film in step S3 are stacked layer by layer, pressed, and cured to shape. The pressing pressure is 0.5 MPa, the temperature is 40° C., and the time is 30 minutes to obtain a shielding sheath.

[0067] The total shielding effectiveness SE of the electromagnetic shielding composite material prepared by aramid fiber, pretreated carbon fiber and electromagnetic shielding film in this embodiment is tested. T It is 74.9dB.

[0068] Example 4

[0069] This embodiment provides a method for preparing a non-metallic electromagnetic shielding sheath, which specifically includes the following steps:

[0070] Step S1, cutting the carbon fiber and aramid fiber into appropriate sizes, and placing the cut carbon fiber in an oven at 120° C. for 1 hour for pretreatment to obtain pretreated carbon fiber;

[0071] Step S2, mixing the polyvinylidene fluoride resin and the auxiliary agent (leveling agent) in a mass ratio of 100:1, and magnetically stirring until the mixture is uniform to obtain a polymer solution;

[0072] 95 parts by mass of the polymer solution were added with 3 parts by mass of multi-walled carbon nanotubes and 2 parts by mass of graphene, and stirred until uniformly dispersed to obtain a mixed slurry A;

[0073] 88 parts by mass of the polymer solution were taken, 12 parts by mass of magnetic ferrosoferric oxide particles were added thereto, and the mixture was stirred until uniformly dispersed to obtain a mixed slurry B;

[0074] Step S3: take the surface density as 10g / m 2 , carbon fiber paper manufactured by Jiangsu Zeyusen Carbon Fiber Technology Co., Ltd.; the mixed slurries A and B are coated on the upper and lower surfaces of the carbon fiber paper, respectively, with coating thicknesses of 600 μm and 800 μm, respectively, and dried to form an electromagnetic shielding film;

[0075] S4. The aramid fibers cut in step S1, the pretreated carbon fibers, and the electromagnetic shielding film in step S3 are stacked layer by layer, pressed, and cured to shape. The pressing pressure is 1.5 MPa, the temperature is 60° C., and the time is 20 min to obtain a shielding sheath.

[0076] The total shielding effectiveness SE of the electromagnetic shielding composite material prepared by aramid fiber, pretreated carbon fiber and electromagnetic shielding film in this embodiment is tested. T It is 76.5dB.

[0077] Example 5

[0078] This embodiment provides a method for preparing a non-metallic electromagnetic shielding sheath, which specifically includes the following steps:

[0079] Step S1, cutting the carbon fiber and aramid fiber into appropriate sizes, and placing the cut carbon fiber in an oven at 120° C. for 1 hour for pretreatment to obtain pretreated carbon fiber;

[0080] Step S2, mixing the polydimethylsiloxane resin and the auxiliary agent (thickener) in a mass ratio of 100:1, and magnetically stirring until the mixture is uniformly mixed to obtain a polymer solution;

[0081] 92 parts by mass of the polymer solution were added with 3 parts by mass of multi-walled carbon nanotubes and 5 parts by mass of graphene, and stirred until uniformly dispersed to obtain a mixed slurry A;

[0082] 90 parts by mass of the polymer solution were added with 10 parts by mass of magnetic ferrosoferric oxide particles, and stirred until uniformly dispersed to obtain a mixed slurry B;

[0083] Step S3: take the surface density as 30g / m 2 , carbon fiber paper manufactured by Jiangsu Zeyusen Carbon Fiber Technology Co., Ltd.; coating the mixed slurries A and B on the upper and lower surfaces of the carbon fiber paper to a coating thickness of 1000 μm and 1000 μm, respectively, and drying to form an electromagnetic shielding film;

[0084] S4. The aramid fibers cut in step S1, the pretreated carbon fibers, and the electromagnetic shielding film in step S3 are stacked layer by layer, pressed, and cured to shape. The pressing pressure is 0.4 MPa, the temperature is 50° C., and the time is 30 minutes to obtain a shielding sheath.

[0085] The total shielding effectiveness SE of the electromagnetic shielding composite material prepared by aramid fiber, pretreated carbon fiber and electromagnetic shielding film in this embodiment is tested. T It is 84.3dB.

[0086] Table 1 Comparison of shielding effectiveness of electromagnetic shielding sheaths

[0087] sample <![CDATA[SE A (dB)]]> <![CDATA[SE R (dB)]]> <![CDATA[SE T (dB)]]> Comparative Example 1 32.0 6.0 38.0 Example 1 66.2 7.1 73.3 Example 2 71.3 7.0 78.4 Example 3 67.3 7.6 74.9 Example 4 69.6 6.9 76.5 Example 5 77.2 7.1 84.3

[0088] The total shielding effectiveness of the electromagnetic shielding sheaths tested in Examples 1-5 shows that the shielding effectiveness of the sheath prepared by the present invention can reach more than 70dB, and the electromagnetic wave shielding effectiveness is excellent. By regulating the conductive particles, magnetic particles and the number of carbon paper layers, the shielding effectiveness of the resulting sheath varies. When a shielding sheath made of a thin film of conductive and magnetic particles and carbon paper is used, the shielding effectiveness of the sheath is above 70dB, indicating that the shielding sheath prepared by the present invention can shield more than 99.99999% of electromagnetic waves and has relatively excellent shielding effectiveness. The shielding effectiveness of the sheath can be selected and regulated according to the amount of particles added and the number of carbon paper layers.

[0089] Because each material has different electromagnetic shielding effectiveness, stacking multiple materials together can leverage their strengths and improve overall shielding performance. The properties of different materials complement each other, forming a complex layered structure that effectively reduces the penetration of electromagnetic radiation or interference. Furthermore, during the propagation of electromagnetic waves, multiple reflections and absorptions occur, increasing the path length of the electromagnetic wave and reducing the probability of electromagnetic wave penetration.

[0090] Figure 1 is a SEM image of the electromagnetic shielding film prepared in Example 3 of the present invention; Figure 2 It is the shielding effectiveness diagram of the electromagnetic shielding sheath in the present invention. Figure 1 and Figure 2The test results show that the SEM image shows that the electromagnetic shielding film has a three-layer structure, namely the carbon paper layer in the middle and the conductive and magnetic layers on both sides. Under a high-power microscope, it can be found that the fibers are closely connected and the fillers are evenly dispersed in the matrix, forming an interconnected conductive network. Figure 2 Test results show that the non-metallic electromagnetic shielding sheath of the present invention achieves an electromagnetic shielding effectiveness exceeding 70dB in the 8.2GHz-12.4GHz (X-band) frequency range, demonstrating excellent electromagnetic shielding effectiveness. By stacking different materials together, the present invention leverages the strengths of each, achieving high shielding effectiveness with a low filler mass fraction.

[0091] Those skilled in the art will appreciate that the foregoing descriptions are merely specific embodiments of the present invention, and not exhaustive. It should be noted that numerous variations and modifications are possible for those skilled in the art, and all such variations and modifications that do not exceed the scope of the claims should be considered within the scope of protection of the present invention.

Claims

1. A method for preparing a non-metallic electromagnetic shielding sheath, characterized in that: The following steps are involved: S1, cutting the carbon fiber and aramid fiber into appropriate sizes, and pretreating the cut carbon fiber to obtain pretreated carbon fiber; S2. Mix the polymer and the additive in a mass ratio of 100:(0.1-1.0), and stir until uniformly dispersed to obtain a polymer solution; Take 90-99 parts by mass of the polymer solution, add 1-10 parts by mass of conductive particles thereto, and stir until uniformly dispersed to prepare 100 parts by mass of mixed slurry A; Take 80-95 parts by mass of the polymer solution, add 5-20 parts by mass of magnetic particles thereto, and stir until uniformly dispersed to prepare 100 parts by mass of mixed slurry B; S3, coating mixed slurry A on one side of the carbon fiber paper, and coating mixed slurry B on the other side of the carbon fiber paper, with a coating thickness of 100-1000 μm, and drying to obtain an electromagnetic shielding film; S4, laminating the aramid fibers cut in step S1, the pretreated carbon fibers, and the electromagnetic shielding film obtained in step S3, pressing and curing them to obtain a shielding sheath; There is no particular order for steps S1 and S2.

2. The method for preparing a non-metallic electromagnetic shielding sheath according to claim 1, characterized in that: The carbon fiber is pretreated in step S1 by placing it in an oven at 120-180°C for 1-2 hours, or soaking it in ethanol for 0.5-1 hour and then drying it.

3. The method for preparing a non-metallic electromagnetic shielding sheath according to claim 1, characterized in that: The polymer is one or a combination of two or more of polyvinyl alcohol, polyacrylamide, polyurethane, polyvinylidene fluoride and polydimethylsiloxane, and the mixing and stirring time of the polymer and the auxiliary agent is 10 to 60 minutes.

4. The method for preparing a non-metallic electromagnetic shielding sheath according to claim 1, characterized in that: The surface density of the carbon fiber paper is 10 g / m 2 , 15 g / m 2 , 20 g / m 2 or 30g / m 2 .

5. The method for preparing a non-metallic electromagnetic shielding sheath according to claim 1, characterized in that: The process parameters for pressing in step S4 are: pressure 0.1-2.0 MPa, temperature 30-80° C., and time 10-60 min.

6. The method for preparing a non-metallic electromagnetic shielding sheath according to claim 1, characterized in that: The auxiliary agent is one or a combination of two or more of a thickener, a defoamer, a dispersant and a leveling agent.

7. The method for preparing a non-metallic electromagnetic shielding sheath according to claim 1, characterized in that: The conductive particles are one or a combination of two or more of graphene, carbon nanotubes and carbon black.

8. The method for preparing a non-metallic electromagnetic shielding sheath according to claim 1, characterized in that: The magnetic particles are NiCo nano alloy particles or Fe3O4 nano particles.

9. The method for preparing a non-metallic electromagnetic shielding sheath according to claim 1, characterized in that: In step S2, magnetic stirring is used to stir until the mixture is uniformly dispersed, with a stirring speed of 100-800 r / min and a stirring time of 30-60 min.

10. A non-metallic electromagnetic shielding sheath produced by the method for producing a non-metallic electromagnetic shielding sheath according to any one of claims 1 to 9.

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