Electromagnetic shielding film and manufacturing method thereof, electronic component, structural member and electronic equipment

Abstract

The invention provides an electromagnetic shielding film and a manufacturing method thereof, an electronic component, a structural member and electronic equipment. The electromagnetic shielding film provided by the invention comprises the high-molecular polymer and the non-metal-based conductive material, and the high-molecular polymer can be used as a carrier of the non-metal-based conductive material, so that charge carriers in the non-metal-based conductive material can freely move in the electromagnetic shielding film to reflect electromagnetic waves. Meanwhile, the high-molecular polymer can be used as a skeleton structure of the electromagnetic shielding film, and electromagnetic waves can be subjected to multiple reflection and multiple scattering in the structure of the electromagnetic shielding film, so that the electromagnetic shielding performance can be effectively improved. Therefore, the electromagnetic shielding film comprising the high-molecular polymer and the non-metal-based conductive material has good electromagnetic interference shielding performance. In addition, the high-molecular polymer in the electromagnetic shielding film enables the structure of the electromagnetic shielding film to be stable and the mechanical property of the electromagnetic shielding film to be good.

Description

Technical Field

[0001] The present disclosure relates to the technical field of electromagnetic shielding materials, and in particular to an electromagnetic shielding film and a manufacturing method thereof, electronic components, structural parts and electronic equipment. Background Art

[0002] With the widespread use of electronic devices, electromagnetic interference (EMI) issues are increasing. Electromagnetic shielding films can shield and reflect EMI from electronic devices, ensuring stable operation. Currently, the materials used to form EMI shielding films include metal-based and non-metal-based materials. Due to the high density, corrosion susceptibility, and difficulty in processing of metal-based materials, non-metal-based materials are becoming the mainstream.

[0003] However, although the electromagnetic shielding film layer formed directly from non-metallic-based shielding materials has high conductivity, its electromagnetic interference shielding performance is still poor, and the structural reliability of the electromagnetic shielding film layer is poor. Summary of the Invention

[0004] In order to overcome the problems existing in the related art, the present disclosure provides an electromagnetic shielding film and a manufacturing method, an electronic component, a structural part and an electronic device.

[0005] According to a first aspect of the present disclosure, an electromagnetic shielding film is provided, comprising: a high molecular polymer and a non-metal-based conductive material in a preset mass ratio.

[0006] In some embodiments of the present disclosure, the preset mass ratio of the non-metal-based conductive material to the high molecular polymer is 1:9 to 1:1.

[0007] In some embodiments of the present disclosure, the electromagnetic shielding effectiveness of the electromagnetic shielding film is 10dB-60dB.

[0008] In some embodiments of the present disclosure, the tensile stress of the electromagnetic shielding film is 200 MPa-320 MPa, and the elongation at break of the electromagnetic shielding film is 2.2%-4.4%.

[0009] In some embodiments of the present disclosure, the conductivity of the electromagnetic shielding film is 20S / m-120S / m.

[0010] In some embodiments of the present disclosure, the density of the electromagnetic shielding film is 1.6 g / cm 3 -2.7g / cm 3 .

[0011] In some embodiments of the present disclosure, the high molecular weight polymer is a water-soluble polymer;

[0012] The high molecular polymer includes one or more of polyvinyl alcohol, polyacrylamide, polyethylene oxide, waterborne polyurethane, gelatin, cellulose, and modified cellulose.

[0013] In some embodiments of the present disclosure, in the electromagnetic shielding film, the high molecular polymer and the non-metal-based conductive material are in a physically mixed state, and the two are connected by hydrogen bonds.

[0014] In some embodiments of the present disclosure, the non-metal-based conductive material includes a carbon-containing conductive material;

[0015] The carbon-containing conductive material includes one or more of graphene, carbon nanotubes, transition metal carbides, transition metal nitrides, transition metal carbonitrides, and conductive carbon black.

[0016] In some embodiments of the present disclosure, the electromagnetic shielding film has a thickness of 12 μm-18 μm.

[0017] In some embodiments of the present disclosure, the outer surface of the electromagnetic shielding film includes a hydrophobic layer.

[0018] In some embodiments of the present disclosure, the water contact angle of the electromagnetic shielding film including the hydrophobic layer is (90°, 105°).

[0019] In some embodiments of the present disclosure, the material of the hydrophobic layer includes polyurethane adhesive or polydimethylsiloxane.

[0020] According to a second aspect of the present disclosure, a method for manufacturing an electromagnetic shielding film is provided, the method comprising:

[0021] Dispersing the high molecular weight polymer in a predetermined solvent to form a first solution;

[0022] Dispersing a non-metal-based conductive material in the predetermined solvent to form a second solution;

[0023] mixing the first solution and the second solution in a first preset ratio to obtain a mixed solution;

[0024] Under a first preset condition, the mixed solution is sprayed on a substrate to obtain the electromagnetic shielding film, which includes the high molecular polymer and the non-metal-based conductive material in a preset mass ratio.

[0025] In some embodiments of the present disclosure, the first preset ratio includes: in the mixed solution, the solid content ratio of the non-metal-based conductive material to the high molecular polymer is the preset mass ratio, and the preset mass ratio is 1:9 to 1:1.

[0026] In some embodiments of the present disclosure, the viscosity of the first solution is 40 mPa·s-200 mPa·s; and / or,

[0027] The mass concentration of the second solution is 30 mg / ml-40 mg / ml.

[0028] In some embodiments of the present disclosure, when the non-metal-based conductive material is MXene, the MXene includes one or more of transition metal carbides, transition metal nitrides, and transition metal carbonitrides, and the method of forming the second solution includes:

[0029] adding a first weight of a fluoride salt to a predetermined volume of an acid solution having a predetermined concentration, stirring until the fluoride salt is dissolved, and then adding a second weight of a MAX phase ceramic to the acid solution;

[0030] Under a second preset condition, stirring the acid solution mixed with the MAX phase ceramic and the fluoride salt to remove the A atomic layer in the MAX phase ceramic to obtain a semi-finished product;

[0031] The semi-finished product is washed multiple times with deionized water. After the pH of the washing solution is greater than or equal to a preset pH, the semi-finished product is centrifuged, and the supernatant obtained by the centrifugation is used as the second solution containing the MXene.

[0032] In some embodiments of the present disclosure, when the fluoride salt includes lithium fluoride and the MAX phase ceramic includes Ti3AlC2, the first weight is 5.00g-8.00g, and the second weight is 3.13g-5.00g; and / or,

[0033] When the acid solution includes a hydrochloric acid solution, the preset concentration is 3 mol / L-6 mol / L, and the preset volume is 60 ml-100 ml.

[0034] In some embodiments of the present disclosure, the preset pH is 6.0.

[0035] In some embodiments of the present disclosure, the second preset condition includes at least one of the following:

[0036] The reaction temperature is 32°C-38°C;

[0037] The reaction time is 22h-26h.

[0038] In some embodiments of the present disclosure, the first preset condition includes at least one of the following:

[0039] Spraying pressure is 1.0MPa-2.7MPa;

[0040] The spraying speed is 95ml / h-105ml / h.

[0041] In some embodiments of the present disclosure, the preset solvent includes one or more of deionized water, methanol, ethanol, and N,N-dimethylformamide.

[0042] In some embodiments of the present disclosure, the manufacturing method further includes:

[0043] preparing a hydrophobic treatment liquid comprising a first component and a second component mixed in a second predetermined ratio;

[0044] The electromagnetic shielding film is immersed in the hydrophobic treatment liquid and reacted under a third preset condition, so that a hydrophobic layer is formed on the outer surface of the electromagnetic shielding film.

[0045] In some embodiments of the present disclosure, the first component includes acetonitrile and adipic acid polyester polyol, and the second component includes isocyanate; or

[0046] The first component includes polydimethylsiloxane prepolymer and a platinum catalyst, and the second component includes vinyl silicone oil and a crosslinking agent.

[0047] In some embodiments of the present disclosure, in the first component, the volume ratio of the acetonitrile to the adipic acid polyester polyol is 6:1 to 4:1; and / or,

[0048] The second preset ratio includes: a volume ratio of the first component to the second component is 9:1 to 3:1.

[0049] In some embodiments of the present disclosure, the third preset condition includes at least one of the following:

[0050] The reaction temperature is 68°C-72°C;

[0051] The reaction time is 1.8h-2.2h.

[0052] According to a third aspect of the present disclosure, an electronic component is provided, comprising a component body and the electromagnetic shielding film provided by the first aspect of the present disclosure, wherein the electromagnetic shielding film covers an outer surface of the component body.

[0053] According to a fourth aspect of the present disclosure, a structural member is provided. The structural member is made of the electromagnetic shielding film provided by the first aspect of the present disclosure.

[0054] According to a fifth aspect of the present disclosure, an electronic device is provided, which includes the electronic components provided by the third aspect of the present disclosure and / or the structural parts provided by the fourth aspect of the present disclosure.

[0055] The technical solutions provided by the embodiments of the present disclosure may include the following beneficial effects: the electromagnetic shielding film includes a polymer and a non-metallic conductive material, and the polymer can serve as a carrier for the non-metallic conductive material, allowing charge carriers in the non-metallic conductive material to move freely within the electromagnetic shielding film, reflecting electromagnetic waves. Furthermore, the polymer can serve as the skeletal structure of the electromagnetic shielding film, and electromagnetic waves can also undergo multiple reflections and scattering within the structure of the electromagnetic shielding film. Therefore, the electromagnetic shielding film including the polymer and the non-metallic conductive material has excellent electromagnetic interference shielding performance. Furthermore, the polymer in the electromagnetic shielding film can also stabilize the structure of the electromagnetic shielding film, and the electromagnetic shielding film has excellent mechanical properties.

[0056] It is to be understood that the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0057] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the invention and, together with the description, serve to explain the principles of the invention.

[0058] Figure 1 is a schematic diagram of an electromagnetic shielding film according to an exemplary embodiment.

[0059] Figure 2 1 is an XRD diffraction pattern of an electromagnetic shielding film containing MXene with different mass proportions according to an exemplary embodiment.

[0060] Figure 3 1 is a stress-strain curve of an electromagnetic shielding film containing MXene with different mass proportions according to an exemplary embodiment.

[0061] Figure 4 1 is a graph showing the electromagnetic shielding performance of an electromagnetic shielding film containing MXene at different mass ratios according to an exemplary embodiment.

[0062] Figure 5 Schematic diagram of the conductivity of electromagnetic shielding films containing MXene at different mass percentages according to an exemplary embodiment.

[0063] Figure 6 3 is a schematic diagram showing the density of electromagnetic shielding films containing MXene at different mass ratios according to an exemplary embodiment.

[0064] Figure 7 It is a schematic diagram of a bending stability test of an electromagnetic shielding film according to an exemplary embodiment.

[0065] Figure 8FIG. 4 is a schematic diagram showing a water contact angle test of an electromagnetic shielding film having a hydrophobic layer according to an exemplary embodiment.

[0066] Figure 9 FIG. 1 is a comparison diagram showing the electromagnetic interference shielding performance and resistance ratio change of an electromagnetic shielding film with a hydrophobic layer and without a hydrophobic layer according to an exemplary embodiment.

[0067] Figure 10 1 is an XPS graph of an electromagnetic shielding film having a hydrophobic layer and not having a hydrophobic layer according to an exemplary embodiment.

[0068] Figure 11 FIG. 4 is an EDS spectrum diagram of an electromagnetic shielding film having a hydrophobic layer according to an exemplary embodiment.

[0069] Figure 12 The figure is a flow chart of a method for manufacturing an electromagnetic shielding film according to an exemplary embodiment. DETAILED DESCRIPTION

[0070] Exemplary embodiments will be described in detail herein, with examples illustrated in the accompanying drawings. In the following description, when referring to the drawings, identical numerals in different figures represent identical or similar elements, unless otherwise indicated. The embodiments described in the following exemplary embodiments are not intended to represent all possible embodiments consistent with the present disclosure. Rather, they are merely examples of apparatus and methods consistent with certain aspects of the present disclosure, as detailed in the appended claims.

[0071] Since static charges become static electricity, when different electrostatic potentials approach each other, electrostatic discharge occurs, generating current, which in turn generates a magnetic field around the current. Similarly, the magnetic field can also stimulate an electric field. Therefore, "electromagnetism" is a general term for the electrical and magnetic properties of an object. When electronic components operate under the stimulation of electric or magnetic fields, the electromagnetic energy they generate can easily interfere with other components, causing them to malfunction. At the same time, the electromagnetic energy generated by other components can also easily interfere with the components themselves. Electromagnetic interference (EMI) signals can be transmitted through connected circuits, radiated through transmission media such as air in the form of electromagnetic waves, or simultaneously through multiple pathways.

[0072] With the widespread use of electronic devices, electromagnetic interference (EMI) issues are increasing. Currently, the materials used to form electromagnetic shielding films include metal-based and non-metal-based materials. Due to the high density, corrosion susceptibility, and processing difficulties of metal-based materials, non-metal-based materials have gradually become the mainstream. However, while EMI shielding films formed directly from non-metal-based materials have high conductivity, their EMI shielding performance remains poor, and the structural reliability of the EMI shielding films is also poor.

[0073] In view of this, the present disclosure provides an electromagnetic shielding film comprising a polymer and a non-metallic conductive material in a predetermined mass ratio. The polymer serves as a carrier for the non-metallic conductive material, allowing charge carriers in the non-metallic conductive material to move freely within the electromagnetic shielding film, thereby reflecting electromagnetic waves. Furthermore, the polymer serves as the skeletal structure of the electromagnetic shielding film, allowing electromagnetic waves to undergo multiple reflections and scattering within the structure of the electromagnetic shielding film. Consequently, the electromagnetic shielding film comprising the polymer and the non-metallic conductive material exhibits excellent electromagnetic interference shielding performance. Furthermore, the polymer in the electromagnetic shielding film stabilizes the structure of the electromagnetic shielding film, resulting in excellent mechanical properties.

[0074] An exemplary embodiment of the present disclosure provides an electromagnetic shielding film. When the electromagnetic shielding film covers a certain component or device, the electromagnetic shielding film has good shielding performance against electromagnetic interference signals, and has good absorption and / or reflection effects on electromagnetic interference signals, ensuring that the covered component or device will not be interfered with by external electromagnetic interference signals, and can also prevent the electromagnetic interference signals generated by the covered component or device from propagating to the outside world and causing interference to external equipment.

[0075] The electromagnetic shielding film includes a high molecular weight polymer and a non-metallic conductive material in a predetermined mass ratio. The non-metallic conductive material may include carbon-based conductive materials such as graphene, carbon nanotubes, and carbon fibers, composite conductive materials such as nickel-plated graphene and nickel-plated carbon fibers, and polymer-based conductive materials such as polyaniline, polypyrrole, and polythiophene. The non-metallic conductive material may contain or generate charge carriers, thereby forming conductive pathways in the electromagnetic shielding film. This allows the electromagnetic shielding film to function as a conductor with a certain electrical conductivity, achieving electromagnetic interference shielding through reflection loss, absorption loss, and multiple reflection attenuation.

[0076] In some examples, the non-metallic conductive material can be a carbon-containing conductive material, which can include one or more materials such as conductive graphite, graphene, carbon nanotubes, conductive carbon black, and MXene. Graphene is an allotrope of carbon with a single-layer hexagonal honeycomb lattice structure. Due to its two-dimensional structure, it has a large surface area and can provide the electromagnetic shielding film with high charge carrier mobility and thermal conductivity. For example, the graphene can be a single-layer graphene or a multi-layer graphene, and the thickness of the graphene sheet can be between 0.4 nm and 0.6 nm.

[0077] MXene is a two-dimensional graphene-like layer structure obtained by processing MAX phase ceramics, wherein M refers to a transition metal element, A refers to a main group element, and X refers to a carbon element and / or a nitrogen element. Since transition metal elements have a strong bond energy with carbon elements and / or nitrogen elements, and main group elements have a more active chemical activity, the atomic layer formed by the main group elements can be removed from the MAX phase ceramics to form MXene. In other words, MXene is a general term for the family of transition metal carbides, transition metal nitrides, and transition metal carbonitrides. MXene sheets have excellent electrical conductivity and a certain degree of hydrophilicity, and can provide excellent reflection loss performance for electromagnetic shielding films. Exemplarily, the thickness of the MXene sheet can be between 1.3nm and 1.7nm.

[0078] Carbon nanotubes are coaxial nanotubes composed of hexagonally arranged carbon atoms. They have a one-dimensional structure and a high aspect ratio. They can form a network structure, which improves the effective conductive path without sacrificing the flexibility and elasticity of the material. Therefore, they have good electrical conductivity and mechanical properties, which is conducive to the formation of flexible electromagnetic shielding films. For example, the diameter of the carbon nanotubes can be between 13nm and 17nm. Conductive carbon black is a type of amorphous carbon that exists in the form of colloidal primary particles that are approximately spherical. They can form spatial network channels and provide high charge carrier mobility for electromagnetic shielding films.

[0079] Since carbon-containing conductive materials are rich in charge carriers, the electromagnetic shielding film has good conductivity, and the charge carriers can move freely in the electromagnetic shielding film. When electromagnetic waves are incident on the electromagnetic shielding film, the electromagnetic shielding film can reflect part of the electromagnetic waves and reduce the electromagnetic waves incident on the electromagnetic shielding film. That is, the electromagnetic shielding film can play a role in reflection loss of electromagnetic waves.

[0080] The electromagnetic shielding film also includes polymers, which refer to high molecular weight compounds formed by repeatedly connecting many identical, simple structural units. In some examples, the polymer may include materials such as epoxy resin, polylactic acid, acrylonitrile-butyl acrylate-styrene copolymer (acrylonitile-acrylate-styrene, AAS). These polymers are mixed with non-metallic conductive materials, or the raw materials for forming these polymers are mixed with non-metallic conductive materials, and electromagnetic shielding films are formed by solution dispersion, 3D printing, impregnation and other methods. In the electromagnetic shielding film, the polymer forms a porous skeleton with a high internal surface area, so that part of the electromagnetic waves incident on the electromagnetic shielding film can be multiply reflected or multiply scattered in the electromagnetic shielding film, thereby preventing the electromagnetic waves from penetrating the electromagnetic shielding film. That is, the electromagnetic shielding film including the polymer can reflect and attenuate the incident electromagnetic waves.

[0081] In other examples, the polymer compound disclosed herein may include a water-soluble polymer, and the water-soluble polymer and the non-metallic-based conductive material are added to a volatile polar solvent to form a mixed solution, and the mixed solution is sprayed or coated to form an electromagnetic shielding film. Water-soluble polymers are a type of polymer material with strong hydrophilicity. The molecular structure of the water-soluble polymer contains a large number of hydrophilic groups. The hydrophilic groups of the water-soluble polymer molecules can form hydrogen bonds with water molecules or polar solvent molecules, so that the mixed solution forms a uniform and stable dispersion system. At the same time, because the water-soluble polymer molecules contain hydrophilic groups and a certain number of hydrophobic groups, the water-soluble polymer has a certain surface activity. When it is dissolved or swelled in a polar solvent, the surface tension of the polar solvent in the mixed solution can be reduced, which is beneficial to the wetting of the non-metallic-based conductive material by the polar solvent, thereby facilitating the non-metallic-based conductive material to maintain a uniform and stable dispersion in the mixed solution. In this way, the non-metallic-based conductive material and the water-soluble polymer in the electromagnetic shielding film formed by the spraying or coating process can be evenly distributed, and the electromagnetic shielding film has stable and uniform electromagnetic interference shielding performance.

[0082] For example, when the high molecular polymer in the electromagnetic shielding film includes a water-soluble polymer, the water-soluble polymer may include one or more of polyvinyl alcohol (PVA), polyacrylic amide (PAM), polyethylene oxide (PEO), aqueous polyurethane, gelatin, cellulose, and modified cellulose. The above-mentioned water-soluble polymer has good film-forming properties and can provide structural support for the non-metallic conductive material in the electromagnetic shielding film, so that the formed electromagnetic shielding film has good mechanical properties and flexibility.

[0083] Polyvinyl alcohol (PVA) is rich in polar hydroxyl groups, which facilitate the formation of a cross-linked network structure in electromagnetic shielding films, ensuring good compatibility with non-metallic conductive materials and resulting in excellent mechanical properties. Polyethylene oxide (PEO) has a regular linear helical structure, resulting in excellent mechanical properties for electromagnetic shielding films. Polyacrylamide (PAA) contains polar amide groups in its structural units, which facilitate compatibility with non-metallic conductive materials and result in excellent mechanical properties for electromagnetic shielding films. Waterborne polyurethane (PU) exhibits excellent adhesion and flexibility. The presence of polar groups such as amino and ester groups enhances compatibility with non-metallic conductive materials, resulting in excellent weather resistance for electromagnetic shielding films. Gelatin is a natural protein that forms a stable film at room temperature and exhibits good biocompatibility. Cellulose and modified celluloses such as hydroxymethyl cellulose and carboxymethyl cellulose exhibit good biodegradability, excellent film-forming properties, and plasticity, resulting in uniform and stable electromagnetic shielding films.

[0084] It is understandable that, regardless of the material of the polymer, the polymer can serve as a carrier of the non-metallic-based conductive material, and the non-metallic-based conductive material can be evenly distributed in the electromagnetic shielding film so that the charge carriers in the non-metallic-based conductive material can move freely in the electromagnetic shielding film. Since the non-metallic-based conductive material and the polymer can be in physical contact in the electromagnetic shielding film, forming a physical interlocking structure, etc., there are abundant contact interfaces between the polymer and the non-metallic-based conductive material. Since the non-metallic-based conductive material is more likely to be electronegative and the polymer is more likely to be electropositive, the polymer and the non-metallic-based conductive material can easily form an electric dipole at the contact interface between the two, achieving high interface polarization. When the electromagnetic shielding film is in an electromagnetic field environment, the charge center of the electric dipole can be affected by the electromagnetic wave and vibrate and / or transfer. The vibration and / or transfer of the charge center of the electric dipole is continuous and has a lag compared to the frequency of the electromagnetic wave, resulting in energy loss of the electromagnetic interference signal after it enters the sprayed film. Furthermore, electrons in non-metallic conductive materials can absorb electromagnetic energy and migrate to the interlayer channels and surfaces of the non-metallic conductive materials. These migrated electrons dissipate energy by colliding with the crystal lattice of the non-metallic conductive materials. This allows the electromagnetic shielding film to effectively absorb and efficiently dissipate incident electromagnetic waves.

[0085] Furthermore, in addition to being a carrier of non-metallic conductive materials and forming electric dipoles, polymers also serve as the skeleton and supporting structure of electromagnetic shielding films. The stability and reliability of polymers give electromagnetic shielding films good mechanical properties such as tensile strength and flexibility, which in turn gives them excellent structural stability and reliability. Figure 1 As shown, Figure 1 This is a schematic diagram of an electromagnetic shielding film. When attached to a component that requires bending or flexing, the film maintains excellent electromagnetic interference shielding performance even after multiple flexing. Furthermore, the polymer in the electromagnetic shielding film provides structural support for the non-metallic conductive material. The combination of the two optimizes the electron transmission path of the non-metallic conductive material and the electrical performance of the electromagnetic shielding film.

[0086] In the electromagnetic shielding film, the non-metallic-based conductive material and the high molecular weight polymer have a predetermined mass ratio. The predetermined mass ratio can be a mass ratio that enables the resulting electromagnetic shielding film to have both good mechanical properties and electromagnetic shielding performance. When the mass ratio of the high molecular weight polymer in the electromagnetic shielding film is too large and the mass ratio of the non-metallic-based conductive material is too small, the electromagnetic shielding film has good mechanical properties but poor electromagnetic interference shielding performance. When the mass ratio of the non-metallic-based conductive material in the electromagnetic shielding film is too large and the mass ratio of the high molecular weight polymer is too small, the electromagnetic shielding film has good electromagnetic interference shielding performance but poor mechanical properties.

[0087] For example, the preset mass ratio is the mass ratio of the non-metallic conductive material to the polymer. After multiple experiments, the preset mass ratio of the non-metallic conductive material to the polymer can be 1:9 to 1:1, and can be, for example, 1:9, 2:8, 3:7, 4:6, 4.5:5.5, 1:1, and so on. In other words, in the electromagnetic shielding film, the mass proportion of the non-metallic conductive material can be 10%-50%, and the mass proportion of the polymer can be 50%-90%. This ensures that the electromagnetic interference shielding performance and mechanical properties of the electromagnetic shielding film are within the optimal range.

[0088] In some examples, when the high molecular polymer in the electromagnetic shielding film is polyvinyl alcohol and the non-metallic conductive material is MXene, Figure 2 As shown, Figure 2 This is the XRD diffraction pattern of the electromagnetic shielding film containing different mass proportions of MXene. Figure 2 In this graph, the ordinate is intensity, representing the number of collected photons. The abscissa is the 2θ diffraction angle (degree), which is the angle between the incident X-ray and the diffracted line. θ is the diffraction half-angle, which is the angle between the incident X-ray and the crystal plane. Figure 2In the figure, the sharp peak near the vertical axis represents MXene, while the bulge peak around a 20-degree diffraction angle represents polyvinyl alcohol. It can be seen that when the mass proportion of MXene increases, such as when the mass proportion of MXene is 50%, the sharp peak becomes more pronounced and the bulge peak becomes less obvious. On the other hand, when the mass proportion of MXene decreases, such as when the mass proportion of MXene is 20% and the mass proportion of polyvinyl alcohol is 80%, the bulge peak becomes more pronounced.

[0089] In some examples, when the high molecular polymer in the electromagnetic shielding film is polyvinyl alcohol and the non-metallic conductive material is MXene, Figure 3 As shown, Figure 3 This is the stress-strain curve of the electromagnetic shielding film containing different mass proportions of MXene. Figure 3 In the graph, the vertical axis is the tensile strength (Tensile Stress), the unit is MPa, and the horizontal axis is the strain (Strain), that is, the elongation at break, the unit is %. Figure 3 It can be seen that the tensile stress of the electromagnetic shielding film can be between 200MPa and 320MPa, and the elongation at break of the electromagnetic shielding film can be between 2.2% and 4.4%. When the weight percentage of MXene in the electromagnetic shielding film is small and the weight percentage of polyvinyl alcohol is large, the mechanical properties of the electromagnetic shielding film are relatively good. For example, when the weight percentage of MXene in the electromagnetic shielding film is 10%, the tensile stress of the electromagnetic shielding film can exceed 300MPa, and the elongation at break is approximately 4.5%. When the weight percentage of MXene in the electromagnetic shielding film is large, the mechanical properties of the electromagnetic shielding film are correspondingly weaker. For example, when the weight percentage of MXene in the electromagnetic shielding film is 40%, the tensile stress of the electromagnetic shielding film can reach approximately 250MPa, and the elongation at break is approximately 2.5%.

[0090] In some examples, when the high molecular polymer in the electromagnetic shielding film is polyvinyl alcohol and the non-metallic conductive material is MXene, Figure 4 As shown, Figure 4 This is a graph showing the electromagnetic shielding performance of electromagnetic shielding films containing different mass proportions of MXene. Figure 4 In the figure, the vertical axis is the electromagnetic shielding effectiveness (EMI SE), the unit is dB, and the horizontal axis is the electromagnetic wave frequency (Frequency), the unit is GHz. Figure 4It can be seen that the electromagnetic shielding effectiveness of the electromagnetic shielding film at 8GHz-12GHz can be between 10dB and 60dB. When the mass proportion of MXene in the electromagnetic shielding film is relatively small, the number of charge carriers in the electromagnetic shielding film is small, and the electromagnetic interference shielding performance of the electromagnetic shielding film is moderate. For example, when the mass proportion of MXene in the electromagnetic shielding film is 10%, the electromagnetic shielding effectiveness of the electromagnetic shielding film at 8GHz-12GHz can be between 10dB and 20dB. When the mass proportion of MXene in the electromagnetic shielding film is large, the number of charge carriers in the electromagnetic shielding film is large, and the electromagnetic interference shielding performance of the electromagnetic shielding film is excellent. For example, when the mass proportion of MXene in the electromagnetic shielding film is 50%, the electromagnetic shielding effectiveness of the electromagnetic shielding film at 8GHz-12GHz can be between 50dB and 60dB.

[0091] In some examples, reference Figure 5 As shown, Figure 5 It is a schematic diagram of the conductivity of electromagnetic shielding films containing non-metallic conductive materials with different mass proportions. Figure 5 In the figure, the vertical axis is the conductivity (Conductivity), the unit is S / m, and the horizontal axis is the mass proportion of the non-metallic conductive material in the electromagnetic shielding film, the unit is wt%. Figure 5 It can be seen that the conductivity of electromagnetic shielding films can range from 20S / m to 120S / m, and the mass percentage of non-metallic conductive materials in the electromagnetic shielding film is directly proportional to the conductivity of the electromagnetic shielding film. This indicates that the electromagnetic shielding film is rich in charge carriers and has a high polarization loss capability. The electromagnetic shielding film can effectively reflect electromagnetic waves incident on the electromagnetic shielding film, effectively reducing the number of electromagnetic waves incident on the electromagnetic shielding film.

[0092] In some examples, reference Figure 6 As shown, Figure 6 It is a density diagram of electromagnetic shielding films containing non-metallic conductive materials with different mass proportions. Figure 6 In the figure, the vertical axis is density (Density), the unit is g / cm 3 The horizontal axis is the mass percentage of non-metallic conductive materials in the electromagnetic shielding film, in wt%. Figure 6 It can be seen that the density of electromagnetic shielding film can be 1.6g / cm 3 -2.7g / cm 3 The mass ratio of non-metallic conductive materials in electromagnetic shielding films is proportional to the density of electromagnetic shielding films. The density of electromagnetic shielding films is only 2.7g / cm 3, which shows that the electromagnetic shielding film has the advantage of being light in weight. When the electromagnetic shielding film is used to shield electronic components from electromagnetic interference, it can provide good electromagnetic interference shielding performance without adding too much extra weight to the electronic components.

[0093] In some examples, when the high molecular polymer in the electromagnetic shielding film is a water-soluble polymer, since the water-soluble polymer is usually dispersed together with the non-metal-based conductive material in a polar solvent to form a mixed solution when the electromagnetic shielding film is formed, after the polar solvent evaporates to form the electromagnetic shielding film, the high molecular polymer and the non-metal-based conductive material are in a physically mixed state in the electromagnetic shielding film.

[0094] Because water-soluble polymers typically contain hydrogen atoms, they can form covalent hydrides with atoms with high electronegativity and small radius (such as F, O, and N atoms) in the water-soluble polymer. Simultaneously, shared electron pairs between atoms tend to shift toward the electronegative atom, rendering the hydrogen atoms in the water-soluble polymer molecules almost protonated, i.e., electropositive. Furthermore, since non-metallic conductive materials are more prone to electronegativity, the (electropositive) hydrogen atoms on the water-soluble polymer molecules can generate electrostatic attraction with the electronegative atoms on the non-metallic conductive material. This electrostatic attraction is called a hydrogen bond. In other words, in an electromagnetic shielding film, the water-soluble polymer and the non-metallic conductive material can be connected via hydrogen bonds, resulting in a uniform mix and distribution of the water-soluble polymer and the non-metallic conductive material within the film. The water-soluble polymer can provide structural support for the non-metallic conductive material, ensuring uniform distribution of the mechanical and electromagnetic interference shielding properties of the electromagnetic shielding film. For example, hydrogen bonds can be characterized and measured by infrared spectroscopy, nuclear magnetic resonance spectroscopy, X-ray diffraction, atomic force microscopy, Raman spectroscopy, gas phase microwave rotation spectroscopy, neutron inelastic scattering, and the like.

[0095] In some examples, the thickness of the electromagnetic shielding film can be between 12μm and 18μm to ensure that the electromagnetic shielding film has good electromagnetic interference shielding performance, flexibility, and mechanical properties. If the thickness of the electromagnetic shielding film is too large, although the electromagnetic shielding film can contain more non-metallic conductive materials and the electromagnetic interference shielding performance will be better, the bendability of the electromagnetic shielding film will decrease. If the thickness of the electromagnetic shielding film is too small, the mechanical properties of the electromagnetic shielding film will be greatly reduced, and the reliability will be reduced. Figure 7 As shown, Figure 7 This is a schematic diagram of the bending stability test of the electromagnetic shielding film. Figure 7In the figure, the vertical axis is the ratio of the tested resistance R of the electromagnetic shielding film after bending to the original resistance R0 of the electromagnetic shielding film, that is, the vertical axis is (R / R0), and the horizontal axis is the number of bending cycles (Bending cycles). Figure 7 In the 2000-cycle bending test shown in the figure, the ratio of R / R0 basically remains near 1 after multiple bendings, that is, after multiple bendings, the resistance of the electromagnetic shielding film is still close to the original resistance before bending, indicating that the electromagnetic shielding film has good flexibility and bendability, and the electromagnetic interference shielding performance is still stable.

[0096] In some possible embodiments, in addition to the water-soluble polymer and carbon-based conductive material in a predetermined mass ratio, the electromagnetic shielding film may also include a hydrophobic layer coated on its outer surface. The hydrophobic layer may be formed from a material having a certain number of hydrophobic groups. The electromagnetic shielding film having the hydrophobic layer can exhibit excellent hydrophobicity, maintaining good electromagnetic interference shielding performance even in high humidity environments.

[0097] In some examples, reference Figure 8 As shown, Figure 8 Schematic diagram of the water contact angle test of an electromagnetic shielding film having a hydrophobic layer. When a droplet contacts the hydrophobic layer of the electromagnetic shielding film, the angle from the solid-liquid interface through the liquid interior to the gas-liquid interface at the junction of the solid electromagnetic shielding film including the hydrophobic layer, the liquid water droplet, and the air is the water contact angle θ. After measurement, the water contact angle θ of the electromagnetic shielding film including the hydrophobic layer is greater than 90°, that is, the surface tension of the solid-gas interface is less than the surface tension of the liquid-gas interface, the droplet shrinks, and the droplet gathers into beads along the surface of the hydrophobic layer. The hydrophobic layer exhibits hydrophobicity, and the electromagnetic shielding film including the hydrophobic layer is not easily wetted. Exemplarily, after measurement, the water contact angle θ of the electromagnetic shielding film including the hydrophobic layer can be between greater than 90° and less than or equal to 105°, that is, the water contact angle is between (90°, 105°], and the electromagnetic shielding film including the hydrophobic layer can have good reliability in a high humidity environment.

[0098] For example, refer to Figure 9 As shown, Figure 9 This is a comparison chart of the changes in electromagnetic interference shielding performance and resistance ratio measured over time when electromagnetic shielding films with and without a hydrophobic layer are placed in an environment with 95% relative humidity and 65°C. Figure 9In the figure, PA is the electromagnetic shielding film without a hydrophobic layer, C-PA is the electromagnetic shielding film with a hydrophobic layer, the vertical axis on the left is the electromagnetic shielding effectiveness (EMI SE), in dB; the vertical axis on the right is the ratio of the original resistance R0 of the electromagnetic shielding film to the test resistance Rx obtained by testing the electromagnetic shielding film over time, that is, (R0 / Rx), in %; the horizontal axis is the continuous residence time (Time), in days. Figure 9 It can be seen that under high temperature and high humidity conditions, the electromagnetic interference shielding performance and resistance ratio of both the electromagnetic shielding films with and without a hydrophobic layer show a downward trend over time, and the downward trend of the electromagnetic shielding film with a hydrophobic layer is smaller than that of the electromagnetic shielding film without a hydrophobic layer. This shows that the electromagnetic shielding film with a hydrophobic layer has good reliability and durability in high temperature and high humidity environments. At the same time, the hydrophobic layer can also reduce the oxidation probability of the carbon-based conductive material in the electromagnetic shielding film, making the electromagnetic shielding film have excellent anti-oxidation properties in high temperature and high humidity environments.

[0099] It is understood that materials with hydrophobic groups are typically organic polymers. When coated on the outer surface of an electromagnetic shielding film, the hydrophobic groups of the organic polymers face away from the film, forming a hydrophobic surface layer. Furthermore, the pendant groups of the organic polymers can form hydrogen bonds with active hydrogen atoms in the electromagnetic shielding film, or generate interaction forces with the film, firmly bonding the hydrophobic layer to the film, thereby improving the reliability and weather resistance of the electromagnetic shielding film.

[0100] In some examples, the material forming the hydrophobic layer may include polydimethylsiloxane (PDMS). Since PDMS has very low solubility in water and is extremely difficult to absorb moisture, and due to the repulsive effect between the non-polar organic groups on its molecular backbone and the oxygen atoms in water molecules, PDMS has excellent hydrophobicity. Furthermore, the hydrophobic layer formed by PDMS also has excellent heat resistance, chemical stability, electrical insulation, weather resistance, and shear resistance. Therefore, the hydrophobic layer formed by PDMS can provide good protection for the electromagnetic shielding film and improve the mechanical properties of the electromagnetic shielding film.

[0101] In other examples, the material for forming the hydrophobic layer may include a polyurethane adhesive, which is an adhesive containing a carbamate group (-NH-COO-) and / or an isocyanate group (-NCO) in the molecular chain. The polyurethane adhesive system can form a complete and dense coating film that can block the penetration of water or the penetration of water molecules, so that the hydrophobic layer formed by it has good water resistance. At the same time, the active groups in the polyurethane adhesive can react with the active hydrogen in the electromagnetic shielding film to generate covalent cross-linking groups, and since the surface of the electromagnetic shielding film formed by the water-soluble polymer and the carbon-based conductive material is relatively rough, the polyurethane adhesive can penetrate into the recesses or pores on the surface of the electromagnetic shielding film to form an intercalation effect, so that the hydrophobic layer formed by it forms a firm bond with the electromagnetic shielding film. In addition, the hydrophobic layer formed by the polyurethane adhesive is elastic and has good extensibility and high tensile strength, thereby improving the mechanical properties of the electromagnetic shielding film and having strong adaptability to the expansion and contraction deformation of the electromagnetic shielding film.

[0102] For example, refer to Figure 10 As shown, Figure 10 1 and 2 are X-ray photoelectron spectroscopy (XPS) graphs of the electromagnetic shielding film having a hydrophobic layer and not having a hydrophobic layer. Figure 10 In the figure, the vertical axis is intensity, which represents the number of collected photons, and the horizontal axis is the binding energy of electrons, with the unit being eV. Due to the large difference in electronegativity between different atoms, the binding energy of different atoms is also different, forming characteristic peaks on the XPS spectrum. Figure 10 In the figure, PM is the spectrum of the electromagnetic shielding film without a hydrophobic layer, and C-PM is the spectrum of the electromagnetic shielding film with a hydrophobic layer, the material of the hydrophobic layer is polyurethane adhesive. Figure 10 It can be seen that the CO bonds in the electromagnetic shielding film having the hydrophobic layer increase significantly, and C=O bonds appear significantly, which indicates that there is a good covalent cross-linking effect between the hydrophobic layer and the electromagnetic shielding film.

[0103] refer to Figure 11 As shown, Figure 11 It is an energy dispersive X-ray spectroscopy (EDS) diagram of the electromagnetic shielding film having a hydrophobic layer. Figure 11 In the electromagnetic shielding film, the high molecular polymer is polyvinyl alcohol, the non-metallic conductive material is transition metal carbide, specifically carbon titanium, and the material of the hydrophobic layer is polyurethane adhesive. Figure 11 The distribution of various elements in the electromagnetic shielding film can be characterized by Figure 11 It can be seen that the film structure of the electromagnetic shielding film is evenly distributed, and the elements have obvious stratification.

[0104] An exemplary embodiment of the present disclosure provides a method for manufacturing an electromagnetic shielding film, which can be used to manufacture the electromagnetic shielding film provided in the above embodiment, with reference to Figure 12 As shown, Figure 12 FIG1 is a flow chart of a method for manufacturing an electromagnetic shielding film according to an exemplary embodiment. The method for manufacturing an electromagnetic shielding film includes the following steps:

[0105] Step S100: dispersing a high molecular weight polymer in a predetermined solvent to form a first solution;

[0106] Step S200: dispersing a non-metallic conductive material in a predetermined solvent to form a second solution;

[0107] Step S300: mixing the first solution and the second solution in a first preset ratio to obtain a mixed solution;

[0108] Step S400: Under a first preset condition, a mixed solution is sprayed on a substrate to obtain an electromagnetic shielding film, wherein the electromagnetic shielding film includes a high molecular polymer and a non-metallic conductive material in a preset mass ratio.

[0109] In step S100, the high molecular polymer may include polymers such as epoxy resin, polylactic acid, acrylonitrile-butyl acrylate-styrene copolymer, and may also include water-soluble polymers. In some examples, the high molecular polymer is a water-soluble polymer, and the water-soluble polymer may include one or more of polyvinyl alcohol, polyacrylamide, polyethylene oxide, water-based polyurethane, gelatin, cellulose, and modified cellulose. Since the molecular structure of the water-soluble polymer includes hydrophilic groups, the preset solvent may be a polar solvent containing polar groups such as hydroxyl (-OH) or carbonyl (-C=O), and the preset solvent may include one or more of deionized water, methanol, ethanol, formamide, N,N-dimethylformamide, glycerol, propylene glycol, etc. When the water-soluble polymer is dispersed in the preset solvent, the hydrophilic groups in the water-soluble polymer can form hydrogen bonds with the polar groups in the preset solvent, so that the water-soluble polymer can have good solubility and dispersibility in the preset solvent. It is understandable that after the water-soluble polymer is added to the preset solvent, one or more dispersion methods such as mechanical stirring, high-speed shearing, and ultrasonic treatment can be performed to uniformly disperse the water-soluble polymer in the preset solvent to form a uniform and stable first solution.

[0110] In step S200, the preset solvent used to disperse the non-metallic-based conductive material may also be a polar solvent, and may include, for example, one or more of deionized water, methanol, ethanol, formamide, N,N-dimethylformamide, glycerol, propylene glycol, etc. It is understood that since the preset solvent used to form the second solution is also a polar solvent, the type of the preset solvent used to form the second solution may be the same as or different from the type of the preset solvent used in the first solution, and the type of the preset solvent will not affect the mixing of the first solution and the second solution.

[0111] Non-metallic-based conductive materials may include carbon-containing conductive materials such as graphene, carbon nanotubes, carbon fibers, etc., and may also include composite conductive materials such as nickel-plated graphene, nickel-plated carbon fibers, etc., and may also include polymer conductive materials such as polyaniline, polypyrrole, polythiophene, etc. In some examples, non-metallic-based conductive materials may be carbon-containing conductive materials, and carbon-based conductive materials may include one or more of conductive graphite, graphene, carbon nanotubes, conductive carbon black, MXene, and the like. When the non-metallic-based conductive material is dispersed in a preset solvent, for example, one or more dispersion methods such as mechanical stirring, high-speed shearing, and ultrasonic treatment may be used. The non-metallic-based conductive material will not dissolve in the preset solvent, but will be evenly distributed in the preset solvent in a solid form to form a uniformly dispersed suspension, i.e., the second solution.

[0112] In step S300, the first solution and the second solution are mixed. Because both the first solution and the second solution utilize a predetermined polar solvent, the solvents can achieve good mixing uniformity. Since the mixed solution formed by the mixing of the first solution and the second solution is used in a spraying process to form an electromagnetic shielding film, the first predetermined ratio of the first solution and the second solution can be a volume ratio that facilitates the spraying process of the mixed solution, or a mass ratio that facilitates the electromagnetic shielding film to have good mechanical properties and electromagnetic interference shielding performance. For example, the first solution and the second solution can be mixed uniformly by mechanical stirring, ultrasonic treatment, or the like to obtain a uniformly dispersed mixed solution.

[0113] In the mixed solution, hydrogen bonds are formed between the polymer molecules including the water-soluble polymer and the predetermined solvent molecules, allowing the polymer to be uniformly dispersed in the predetermined solvent. Furthermore, because the water-soluble polymer contains hydrophilic groups and a certain number of hydrophobic groups, the water-soluble polymer has a certain surface activity, which reduces the surface tension of the predetermined solvent in the mixed solution, thereby facilitating the wetting of the non-metallic conductive material by the predetermined solvent, thereby facilitating uniform and stable dispersion of the non-metallic conductive material in the mixed solution. Furthermore, because the hydrogen atoms in the water-soluble polymer are electropositive due to the offset of electron pairs, while the non-metallic conductive material is electronegative due to its abundant charge carriers, the non-metallic conductive material can generate an electrostatic attraction with the water-soluble polymer in the mixed solution. In other words, in the mixed solution, the non-metallic conductive material can form hydrogen bonds with the water-soluble polymer, allowing the non-metallic conductive material to be uniformly and stably dispersed in the mixed solution using the water-soluble polymer as a carrier. This allows the electromagnetic shielding film formed from the mixed solution to have a uniformly distributed structure, mechanical properties, and electromagnetic interference shielding performance.

[0114] In step S400, the electromagnetic shielding film can be formed by spraying technology due to its advantages of low cost, high uniformity and adaptability to irregular surfaces. A mixed solution in a uniform and stable state is added to a spraying device, and a process such as pneumatic spraying, electrospraying, ultrasonic spraying, cold spraying, etc. is used. Under a first preset condition, the spraying device evenly sprays the mixed solution on the substrate. After the preset solvent in the mixed solution is dried and volatilized, an electromagnetic shielding film containing a solid high molecular polymer and a solid non-metallic conductive material is obtained. Since the preset solvent is a polar solvent with a certain volatility, after the mixed solution is sprayed on the substrate, the preset solvent can be completely volatilized after waiting at room temperature for 15 minutes to 30 minutes, thereby obtaining a dry and uniform electromagnetic shielding film.

[0115] The substrate can provide support for the formation of the electromagnetic shielding film. The surface of the substrate in contact with the electromagnetic shielding film has a flat surface, so that the formed electromagnetic shielding film has good uniformity. The present disclosure does not limit the material of the substrate, as long as the surface in contact with the electromagnetic shielding film is flat. In some examples, the substrate material can be cellulose, PET (Polyethylene terephthalate), etc.

[0116] The first preset conditions may be spraying process parameters that ensure good uniformity and thickness consistency of the electromagnetic shielding film formed by spraying, such as spraying pressure, spraying speed, spraying distance, nozzle diameter, and other parameters. In some examples, the first preset conditions may include one or more of the following: the spraying pressure may be between 1.0 MPa and 2.7 MPa, the spraying speed may be between 95 ml / h and 105 ml / h, and the nozzle inner diameter may be between 0.70 mm and 0.74 mm, so that the formed electromagnetic shielding film has good uniformity. In some examples, the spraying speed may be 100 ml / h, and the nozzle inner diameter may be 0.72 mm.

[0117] In the electromagnetic shielding film, the non-metallic-based conductive material and the high molecular weight polymer have a predetermined mass ratio. The predetermined mass ratio can be, for example, a mass ratio that enables the resulting electromagnetic shielding film to have both good mechanical properties and electromagnetic shielding performance. When the mass ratio of the high molecular weight polymer in the electromagnetic shielding film is too large and the mass ratio of the non-metallic-based conductive material is too small, the electromagnetic shielding film has good mechanical properties but poor electromagnetic interference shielding performance. When the mass ratio of the non-metallic-based conductive material in the electromagnetic shielding film is too large and the mass ratio of the high molecular weight polymer is too small, the electromagnetic shielding film has good electromagnetic interference shielding performance but poor mechanical properties.

[0118] It is understandable that before the mixed solution is sprayed on the surface of the substrate, the substrate can be subjected to a hydrophilic treatment to enhance the hydrophilicity of the substrate surface. Hydrophilicity refers to the physical property of molecules that can form short-term bonds with polar solvents through hydrogen bonds. The hydrophilic treatment can be a process of forming polar groups with a greater affinity for water or polar solvents on the surface of the substrate. The polar groups are grafted onto the surface of the substrate to form a large number of side chains on the surface of the substrate to form a hydrophilic layer with affinity for the mixed solution. In this way, when the mixed solution is sprayed on the surface of the substrate, the polar solvent in the mixed solution has a strong adhesion to the substrate, and the mixed solution can stay on the surface of the substrate, slowing down the diffusion of the mixed solution on the surface of the substrate, so that the electromagnetic shielding film formed after the preset solvent in the mixed solution dries and evaporates has good density and uniformity.

[0119] In some possible embodiments, since the polymer has a certain viscosity, when the polymer is dispersed in a preset solvent, the first solution formed also has a certain viscosity. Since the second solution is a suspension, the viscosity of the mixed solution can be controlled by controlling the viscosity of the first solution, thereby ensuring the mixing uniformity of the mixed solution formed by mixing the first solution and the second solution. In this way, the spraying effect of the mixed solution can be ensured, thereby obtaining a uniformly distributed electromagnetic shielding film. For example, regardless of the type and number of polymers in the first solution, the viscosity of the first solution can be controlled between 40mPa·s-200mPa·s, so that when the mixed solution obtained by mixing the first solution and the second solution in a first preset ratio is sprayed, the obtained electromagnetic shielding film has good uniform mechanical properties and electromagnetic interference shielding performance.

[0120] In some examples, when the polymer is polyvinyl alcohol and the preset solvent is deionized water, approximately 10 g of polyvinyl alcohol can be added to approximately 90 ml of deionized water. The deionized water and polyvinyl alcohol are placed in a sealed container and stirred continuously at 60° C. to 95° C. for 10 to 24 hours until the polyvinyl alcohol is dissolved in the water, resulting in a clear, transparent, homogeneous solution, i.e., the first solution. For example, the solids content of the first solution formed by polyvinyl alcohol can be between 2% and 10%, such that the viscosity of the first solution is between 40 mPa·s and 200 mPa·s.

[0121] In other examples, when the water-soluble polymer is gelatin and the preset solvent is deionized water, the gelatin can be added to the deionized water, and the deionized water and polyvinyl alcohol can be placed in the gelatin. The mixture can be stirred continuously at 50°C-70°C for 2-4 hours until the gelatin is dissolved in the water, resulting in a clear, transparent, homogeneous solution, i.e., the first solution. For example, the solids content of the first solution formed by gelatin can be between 5% and 15%, such that the viscosity of the first solution is between 40 mPa·s and 200 mPa·s.

[0122] In other examples, since both cellulose and aqueous polyurethane are readily soluble in water, cellulose or aqueous polyurethane is added to deionized water and dissolved in the deionized water by mechanical stirring, high-speed shearing, or other methods to obtain a uniformly distributed first solution. For example, the solids content of the first solution formed by the aqueous polyurethane can be between 10% and 20%, and the solids content of the first solution formed by the cellulose can be between 0.5% and 2.0%, such that the viscosity of the first solution is between 40 mPa·s and 200 mPa·s.

[0123] In some examples, because the second solution is a suspension, when the first solution and the second solution are mixed in a first preset ratio to form a mixed solution, the concentration of the non-metallic-based conductive material in the second solution can affect the mixing uniformity of the mixed solution. Given a certain viscosity and mixing ratio for the first solution, if the concentration of the non-metallic-based conductive material in the second solution is too high, the water-soluble polymer may not be able to provide sufficient support for the non-metallic-based conductive material, resulting in poor uniformity and stability of the mixed solution. If the concentration of the non-metallic-based conductive material in the second solution is too low, the concentration of the non-metallic-based conductive material in the resulting mixed solution may be too low, which may result in an excessively low mass fraction of the non-metallic-based conductive material in the electromagnetic shielding film formed by spraying the mixed solution, thereby resulting in poor electromagnetic interference shielding performance of the electromagnetic shielding film. For example, the mass concentration of the second solution can be controlled between 30 mg / ml and 40 mg / ml, so that when the mixed solution obtained by mixing the first solution and the second solution in the first preset ratio is sprayed, the resulting electromagnetic shielding film has good electromagnetic interference shielding performance.

[0124] In some examples, the viscosity of the first solution is controlled between 40 mPa·s and 200 mPa·s, and the mass concentration of the second solution is controlled between 30 mg / ml and 40 mg / ml, so that when the mixed solution obtained by mixing the first solution and the second solution in a first preset ratio is sprayed, the obtained electromagnetic shielding film has good uniformity of mechanical properties and electromagnetic interference shielding properties, and has excellent electromagnetic interference shielding properties.

[0125] In some possible embodiments, the first predetermined ratio of the mixture of the first solution and the second solution can be determined based on a predetermined mass ratio of the non-metallic-based conductive material to the polymer in the desired electromagnetic shielding film. Because the predetermined solvents in the first and second solutions evaporate during the formation of the electromagnetic shielding film, the first predetermined ratio can be such that the solid content ratio of the non-metallic-based conductive material to the polymer in the mixed solution meets the predetermined mass ratio.

[0126] For example, when it is determined that the mass ratio of the non-metallic-based conductive material to the high molecular polymer in the electromagnetic shielding film to be formed is 1:1, when the first solution and the second solution are mixed, the first preset ratio only needs to be such that the solid content ratio of the non-metallic-based conductive material to the high molecular polymer in the formed mixed solution is 1:1. For example, when the solid content of the first solution is 10% and the solid content of the second solution is 30%, the first preset ratio when the first solution and the second solution are mixed, that is, the first preset ratio when the first solution and the second solution are mixed, is to control the mixing mass ratio of the first solution to the second solution to be 3:1, so that the solid content ratio of the non-metallic-based conductive material to the high molecular polymer in the mixed solution is 1:1, so that the preset mass ratio of the non-metallic-based conductive material to the high molecular polymer in the electromagnetic shielding film formed by spraying the mixed solution is 1:1.

[0127] The electromagnetic shielding film formed by spraying the mixed solution has a preset mass ratio of non-metallic-based conductive material to polymer. For example, the preset mass ratio of the non-metallic-based conductive material to polymer in the electromagnetic shielding film can be 1:9 to 1:1. That is, the mass proportion of the non-metallic-based conductive material in the electromagnetic shielding film can be 10%-50%, and the mass proportion of the polymer can be 50%-90%, so that the formed electromagnetic shielding film has both good mechanical properties and electromagnetic shielding performance. Therefore, the first preset ratio of the first solution and the second solution to form the mixed solution can be such that the solid content ratio of the non-metallic-based conductive material to the water-soluble polymer in the mixed solution satisfies a ratio of 1:9 to 1:1.

[0128] In some examples, when the non-metallic conductive material is MXene, since MXene includes one or more of transition metal carbides, transition metal nitrides, and transition metal carbonitrides, when forming the second solution, a pre-prepared solid MXene can be added to a predetermined solvent and uniformly dispersed to form the second solution. In other examples, when the non-metallic conductive material is MXene, a MAX phase ceramic can be used as the raw material, and the main group atomic layer in the MAX phase ceramic can be etched to form the second solution. The second method is described in detail below.

[0129] In some possible implementations, when the non-metal-based conductive material is MXene, in step S200 of the method for manufacturing the electromagnetic shielding film provided in the above embodiment, the method for forming the second solution includes:

[0130] Step S210: adding a first weight of fluoride salt to a preset volume of an acid solution having a preset concentration, stirring until the fluoride salt is dissolved, and then adding a second weight of MAX phase ceramic to the acid solution;

[0131] Step S220: stirring the acid solution containing the MAX phase ceramic and the fluoride salt under the second preset condition to remove the A atomic layer in the MAX phase ceramic to obtain a semi-finished product;

[0132] Step S230: The semi-finished product is washed multiple times with deionized water. After the pH of the washing solution is greater than or equal to the preset pH, the semi-finished product is centrifuged, and the supernatant obtained by the centrifugation is used as the second solution containing MXene.

[0133] In this embodiment, the fluoride salt may include a salt containing fluoride ions such as LiF, KF, NaF, CsF, CaF2, tetrabutylammonium fluoride, and the acid solution may include a hydrochloric acid solution or a sulfuric acid solution. MAX phase ceramics are a ternary layered ceramic precursor, wherein M refers to a transition metal element, A refers to a main group element (including Al or Si), and X refers to a carbon element and / or a nitrogen element. Exemplarily, MAX phase ceramics may include but are not limited to Zr3Al3C5, Ti3AlC2, Ti2AlC, Mo2Ga2C, Ti3SiC2, and the like.

[0134] When the fluoride salt and the acid solution are mixed, HF (hydrofluoric acid) can be generated in situ to slowly and selectively etch the A atomic layer in the MAX phase ceramic subsequently added to the acid solution, thereby forming a MXene nanosheet. Based on the type of MAX phase ceramic added to the acid solution, the MXene nanosheet formed may include one or more of transition metal carbides, transition metal nitrides, and transition metal carbonitrides. Because hydrofluoric acid is highly corrosive and highly toxic, and easily causes defects on the surface of the formed MXene, compared to directly etching the MAX phase ceramic with a hydrofluoric acid solution, the mixture of fluoride salt and acid solution to indirectly form HF to prepare MXene nanosheets has the advantages of high yield, small defects, large size, and clean surface.

[0135] Since fluoride salts, acid solutions, and MAX phase ceramics all come in a variety of types, when different types of fluoride salts and MAX phase ceramics are selected, the weights of each added to the acid solution will also vary. Furthermore, when different types of acid solutions are selected, the concentration and volume of the acid solution will also vary. Furthermore, since the active ingredient for selectively etching the A atomic layer in the MAX phase ceramic is HF, where the F ions are provided by the fluoride salt and the H atoms are provided by the acid solution, by varying the molar ratios of the F, H, and A elements in the MAX phase ceramic, single or multilayer MXene sheets with varying degrees of etching can be obtained. Therefore, based on the type of fluoride salt selected during MXene preparation, an appropriate first weight of fluoride salt can be selected; based on the type of acid solution, an appropriate predetermined volume of acid solution with a predetermined concentration can be selected; and based on the type of MAX phase ceramic, an appropriate second weight of MAX phase ceramic can be selected, such that the molar ratios of the F, H, and A elements in the MAX phase ceramic are appropriate, resulting in a MXene with good etching degree and performance.

[0136] After a first weight of a fluoride salt is added to a predetermined volume of an acid solution having a predetermined concentration, the fluoride salt is stirred to dissolve in the acid solution, thereby generating HF in situ with the acid solution and forming cations in the acid solution. A second weight of a MAX phase ceramic is then added to the acid solution, allowing the A atomic layer in the MAX phase ceramic to be selectively etched away by the HF formed in the acid solution.

[0137] Because the reaction rate of the A-atomic layer in the MAX phase ceramic with the HF formed in the acid solution is too slow at room temperature, the acid solution containing the MAX phase ceramic and the fluoride salt is stirred under a second preset condition to accelerate the etching and removal of the A-atomic layer by the HF formed in the acid solution. During the reaction between the MAX phase ceramic and the fluoride salt-mixed acid solution, the cations introduced by the fluoride salt into the acid solution can be intercalated into the MXene, increasing the interlayer spacing of the MXene and facilitating the formation of single-layer or few-layer MXene nanosheets.

[0138] The second preset condition may be a condition suitable for the HF in the acid solution to react with the A atomic layer of the MAX phase ceramic and react completely, for example, it may include the reaction temperature and the reaction time. In some examples, the second preset condition may include at least one of the following: the reaction temperature is between 32°C and 38°C, and the reaction time is between 22h and 26h. For example, the acid solution mixed with MAX phase ceramics and fluoride salts can be placed in a water bath between 32°C and 38°C and continuously stirred for 22h to 26h to fully remove the A atomic layer in the MAX phase ceramics. After the reaction is completed, the reacted solution is dried to obtain a semi-finished product containing MXene. In some examples, the reaction temperature can be 35°C and the reaction time can be 24h.

[0139] Since the semi-finished product obtained after the reaction is completed includes not only MXene but also impurity ions, acid, and MAX phase ceramics that may not have reacted completely, the semi-finished product is washed multiple times with deionized water. For example, the semi-finished product can be washed by centrifugal washing to remove impurity ions, acid and other soluble substances in the semi-finished product. During the multiple washing process, the pH of the cleaning liquid obtained from each washing is measured until the pH of the cleaning liquid is greater than or equal to the preset pH. It can be considered that the impurity ions, acid and other soluble substances in the semi-finished product are completely removed. The preset pH can be the pH at which the impurity ions are determined to be completely removed. In some examples, the preset pH can be a value such as 5.8, 5.9, 6.0, 6.1, 6.2, 6.3, 6.4, 6.5, etc. The larger the value, the higher the degree of impurity removal. In some examples, the preset pH can be 6.0.

[0140] Because MXene has superior hydrophilicity compared to MAX-phase ceramics, after removing impurity ions from the semi-finished product, a predetermined solvent is added and centrifuged. The unreacted MAX-phase ceramic in the semi-finished product settles to form a precipitate, while the MXene is dispersed in the supernatant resulting from the centrifugation, forming a suspension. The precipitate and supernatant are then separated, and the supernatant obtained from the ion separation is used as the second solution containing MXene.

[0141] In some examples, when the fluoride salt includes lithium fluoride (LiF) and the MAX phase ceramic includes Ti3AlC2, the first weight of LiF can be between 5.00 g and 8.00 g, and the second weight of Ti3AlC2 can be between 3.13 g and 5.00 g, so that the molar ratio of LiF to Ti3AlC2 is between 15.10 and 38.58, so that HF ​​formed by the fluoride salt in the acid solution can fully etch and remove the A atomic layer in the MAX phase ceramic.

[0142] In some examples, when the acid solution includes a hydrochloric acid solution, the preset concentration of the hydrochloric acid solution can be between 3 mol / L and 6 mol / L, and the preset volume of the hydrochloric acid solution can be between 60 ml and 100 ml, so that the amount of hydrochloric acid is within a certain range, so that it can fully dissolve the fluoride salt and react with it to form a sufficient amount of HF to ensure that the A atomic layer in the MAX phase ceramic is fully etched and removed.

[0143] In other examples, when the fluoride salt includes lithium fluoride (LiF), the MAX phase ceramic includes Ti3AlC2, and the acid solution includes a hydrochloric acid solution, the first weight of LiF can be between 5.00 g and 8.00 g, the second weight of Ti3AlC2 can be between 3.13 g and 5.00 g, the preset concentration of the hydrochloric acid solution can be between 3 mol / L and 6 mol / L, and the preset volume of the hydrochloric acid solution can be between 60 ml and 100 ml.

[0144] In an exemplary embodiment, the present disclosure provides a method for manufacturing an electromagnetic shielding film, comprising the following steps:

[0145] Step S101: dispersing a high molecular weight polymer in a predetermined solvent to form a first solution;

[0146] Step S102: dispersing a non-metallic conductive material in a predetermined solvent to form a second solution;

[0147] Step S103: mixing the first solution and the second solution in a first preset ratio to obtain a mixed solution;

[0148] Step S104: spraying the mixed solution on the substrate under the first preset condition to obtain an electromagnetic shielding film, wherein the electromagnetic shielding film includes a high molecular polymer and a non-metallic conductive material in a preset mass ratio;

[0149] Step S105: preparing a hydrophobic treatment liquid, wherein the hydrophobic treatment liquid includes a first component and a second component mixed in a second preset ratio;

[0150] Step S106 , immersing the electromagnetic shielding film in a hydrophobic treatment liquid, and reacting under a third preset condition, so that a hydrophobic layer is formed on the outer surface of the electromagnetic shielding film.

[0151] In this embodiment, the implementation of steps S101 to S104 is the same as or similar to the implementation of steps S100 to S400 in the above embodiment, and is not described in detail here.

[0152] Since non-metallic conductive materials are easily oxidized in air, and when the high molecular weight polymer in the electromagnetic shielding film is a water-soluble polymer, the water-soluble polymer is hydrophilic. In high humidity environments, the electromagnetic shielding film easily absorbs water, resulting in a decrease in the reliability, durability, and electromagnetic interference shielding performance of the electromagnetic shielding film. Therefore, a hydrophobic layer is formed on the outer surface of the electromagnetic shielding film to isolate the external air and water vapor, thereby improving the reliability of the electromagnetic shielding film.

[0153] In step S105, the hydrophobic treatment liquid is a reaction liquid used to form a hydrophobic layer on the outer surface of the electromagnetic shielding membrane. The hydrophobic treatment liquid includes a first component and a second component. One of the first component and the second component can be a reaction main agent, and the other can be a cross-linking agent. When the first component and the second component are mixed in a second preset ratio, the active ingredients therein can react with each other to form a hydrophobic material.

[0154] The following description uses the first component as the main reaction agent and the second component as the crosslinking agent as an example. Since the crosslinking agent in the second component reacts with the main reaction agent in the first component, thereby forming a bridge, the second predetermined ratio of the first and second components can be such that the hydrophobic layer formed by the reaction of the main reaction agent and the crosslinking agent can densely coat the electromagnetic shielding film.

[0155] For example, when the hydrophobic treatment liquid is a polyurethane adhesive, the first component is a main reaction agent, and the second component is a crosslinking agent, the first component can include polyether polyols such as polyethylene glycol, polypropylene glycol, and castor oil, or polyester polyols such as polymethyl acrylate and polyester diol; the second component can include aromatic isocyanates such as toluene diisocyanate and diphenylmethane diisocyanate. When the first and second components are mixed in a second predetermined ratio, the hydrophobic treatment liquid is formed, and the polyether polyol or polyester polyol in the first component can react with the isocyanate in the second component to form a hydrophobic polyurethane.

[0156] In some examples, the first component can include acetonitrile and adipic acid polyester polyol. Adipic acid polyester polyol is typically formed by polycondensation of adipic acid with a polyol such as ethylene glycol, propylene glycol, diethylene glycol, trimethylolpropane, pentaerythritol, etc. Acetonitrile is a colorless, transparent organic solvent with thermal stability and low volatility. Due to the high viscosity of adipic acid polyester polyol, acetonitrile is used as a solvent to disperse the adipic acid polyester polyol to form the first component. The isocyanate in the second component can include an aromatic isocyanate such as toluene diisocyanate and diphenylmethane diisocyanate.

[0157] For example, in the first component, acetonitrile and adipic acid polyester polyol can be mixed in a volume ratio of 6:1 to 4:1 so that the formed first component has a suitable viscosity. For example, when the adipic acid polyester polyol is 10ml, the acetonitrile can be 40ml-60ml, and the two are mixed evenly to obtain the first component. When the first component is mixed with the second component, the second preset ratio can be the volume ratio of the first component to the second component. For example, in the hydrophobic treatment liquid, the first component including acetonitrile and adipic acid polyester polyol and the second component including isocyanate can be mixed in a volume ratio of 9:1 to 3:1 so that the hydrophobic layer formed in the hydrophobic treatment liquid can completely and densely cover the electromagnetic shielding film, thereby providing good coating and protection for the electromagnetic shielding film. For example, when the second component is 5ml, the first component can be 15ml-45ml, and the two are mixed evenly to obtain the hydrophobic treatment liquid. For another example, when the first component is 90ml, the second component can be 10ml-30ml, and the two are mixed evenly to obtain the hydrophobic treatment liquid. The polyurethane prepared by using adipic acid polyester polyol and isocyanate has a large number of polar groups such as ester groups and amino groups in the molecule, and has strong cohesive strength and adhesion, so that the formed hydrophobic layer has high mechanical strength and wear resistance.

[0158] In other examples, due to the properties of organosilicon compounds such as low surface tension, high and low temperature resistance, oxidation stability, and water and moisture resistance, the reaction liquid of a synthetic organosilicon compound can be used as the hydrophobic treatment liquid. For example, when the hydrophobic treatment liquid is an organosilicon compound, the first component can include a polydimethylsiloxane prepolymer and a platinum catalyst, and the second component can include a vinyl silicone oil and a crosslinker. The platinum catalyst is used to catalyze the hydrosilylation reaction of the components. Specifically, inorganic substances such as chloroplatinic acid and various platinum-coordinated organic compounds can be used, but are not limited to them. Vinyl silicone oil is a polydimethylsiloxane with at least two vinyl groups directly attached to the Si, and the vinyl groups can be located at the chain ends and / or side chains. The crosslinker is a polydimethylsiloxane containing Si-H groups, and the hydrogen atoms can be located at the chain ends and / or side chains. In some examples, the hydrophobic treatment liquid can be DC184 provided by Dow Corning. When the first and second components are mixed in a second predetermined ratio, the hydrophobic treatment liquid is formed. The first component can react with the second component to form a polydimethylsiloxane with hydrophobicity and good flexibility.

[0159] In step S106, after the first component and the second component are mixed in a second predetermined ratio to form a hydrophobic treatment liquid, the electromagnetic shielding film, due to its flexibility, can be completely removed from the substrate and immersed in the hydrophobic treatment liquid, where it undergoes a reaction under third predetermined conditions. The third predetermined conditions may, for example, be a temperature and a time period that allow the active ingredients in the hydrophobic treatment liquid to react effectively. Under the third predetermined conditions, the groups in the hydrophobic treatment liquid can have a high collision probability, allowing the active ingredients in the hydrophobic treatment liquid to undergo a cross-linking reaction under appropriate conditions, forming a complete and dense hydrophobic layer on the outer surface of the electromagnetic shielding film.

[0160] In some examples, the third preset condition may include at least one of the following: a reaction temperature between 68°C and 72°C, and a reaction time between 1.8h and 2.2h. For example, the hydrophobic treatment liquid soaked with the electromagnetic shielding membrane can be placed in an oven, drying tunnel, or tunnel furnace at a temperature between 68°C and 72°C for 1.8h to 2.2h, so that the active ingredients in the hydrophobic treatment liquid react on the outer surface of the electromagnetic shielding membrane to form a hydrophobic layer covering the outer surface of the electromagnetic shielding membrane. The hydrophobic layer can be connected to the polar groups in the electromagnetic shielding membrane through hydrogen bonds, or it can form a physical chimeric structure with the electromagnetic shielding membrane, so that the hydrophobic layer and the electromagnetic shielding membrane have a firm bonding surface, thereby ensuring the reliability of the electromagnetic shielding membrane coated with the hydrophobic layer. In some examples, the reaction temperature can be 70°C and the reaction time can be 2h.

[0161] It should be noted that, since the hydrophobic layer needs to well coat the electromagnetic shielding film, there is no need to stir the hydrophobic treatment liquid during the reaction to avoid the hydrophobic product formed by the reaction from effectively adhering to the electromagnetic shielding film. After the reaction is completed, the electromagnetic shielding film with the hydrophobic layer coated on the surface is taken out from the hydrophobic treatment liquid. Since there are still some unreacted or incompletely reacted hydrophobic treatment liquid residues adhering to the surface of the hydrophobic layer at this time, acetone can be used to clean and remove the hydrophobic treatment liquid residues. Then, the electromagnetic shielding film coated with the hydrophobic layer is dried at room temperature to obtain an electromagnetic shielding film with good hydrophobicity and reliability. Exemplarily, the water contact angle of the electromagnetic shielding film coated with the hydrophobic layer can be between (90°, 105°].

[0162] In one exemplary embodiment, the present disclosure provides an electronic component. The electronic component may include, for example, connectors, circuit boards, flexible circuit boards, chips, and other elements or devices that can store or transmit data or signals. The component body of an electronic component is the main structure that implements its primary function. During data transmission or operation, signals within the component body are susceptible to electromagnetic interference signals that can affect other devices. The component body is also susceptible to electromagnetic interference signals generated by other devices during operation.

[0163] In order to shield the main body of the component from electromagnetic interference, the electromagnetic shielding film provided by the above embodiment of the present disclosure can be covered on the outer surface of the main body of the component to form an electronic component with good operating performance. For example, a mixed solution that can form an electromagnetic shielding film can be directly sprayed on the surface of the component body, and the solvent can be evaporated to form an electromagnetic shielding film to cover the main body of the component. In other examples, when the outer surface of the electromagnetic shielding film includes a hydrophobic layer, since the hydrophobic layer has good protective properties, the electromagnetic shielding film including the hydrophobic layer can be used to cover the outer surface of the component body, so that the electronic component can also operate well in a high temperature and high humidity environment. It can be understood that since the electronic component includes the electromagnetic shielding film provided by the above embodiment, the electromagnetic shielding film in the electronic component has the above advantages, so that the electronic component has good operating performance and reliability.

[0164] In an exemplary embodiment, the present disclosure provides a structural member, which is made from the electromagnetic shielding film provided in the above-described embodiments of the present disclosure. The structural member can be a structure used for electromagnetic interference shielding, and may include, but is not limited to, a shielding cover, a shielding box, a shielding shell, a shielding bag, a shielding door, and the like. The structural member can be formed by directly cutting or splicing the electromagnetic shielding film, or by applying the electromagnetic shielding film to a supporting material such as a fabric, a woven fabric, or a plastic substrate. Because the structural member is made from the electromagnetic shielding film, the structural member also has the advantages of the electromagnetic shielding film. The structural member can effectively reduce reflection loss, reflection attenuation, and absorption attenuation of electromagnetic waves, thereby providing excellent electromagnetic interference shielding.

[0165] In an exemplary embodiment, the present disclosure further provides an electronic device, which may include, for example, a mobile phone, a tablet computer, a laptop computer, a wristband, a watch, headphones, VR glasses, a sensor, and the like. Because electronic devices require chips to perform functions such as processing and storing data, the electronic devices may be provided with the electronic components provided by the aforementioned embodiments of the present disclosure, so that each electronic component in the electronic device is in good operating condition, thereby ensuring good operating performance.

[0166] In some examples, when an electronic device is performing confidential work, or when the electromagnetic waves of the entire electronic device need to be blocked, the electronic device can be placed in a structural member made of an electromagnetic shielding film. The structural member can play a good electromagnetic interference shielding role to avoid or reduce the transmission of electromagnetic waves generated by the electronic device to the outside world.

[0167] In some examples, electronic devices may contain irregularly structured electronic components. When electromagnetic interference shielding is required, existing shielding covers or shielding films cannot adequately adhere to the structure of the electronic components, resulting in a large space occupation rate and affecting the portability of the electronic device. The electromagnetic shielding film provided by the above-described embodiments of the present disclosure can be used to cover the irregular components. For example, a mixed solution for forming an electromagnetic shielding film can be directly sprayed onto the electronic components to form an electromagnetic shielding film that effectively covers them, thereby improving the portability of the electronic device.

[0168] In some examples, when the electronic device includes a foldable screen mobile phone or a foldable screen tablet computer, it may be necessary to set up flexible electronic materials that are repeatedly in a bent state, such as a flexible circuit board, a hinge connecting the two screens to the circuit board, etc. When electromagnetic interference shielding is required, the existing shielding film layer cannot reliably shield the electromagnetic interference due to its weak structural resistance to bending. The electromagnetic shielding film provided by the above embodiment of the present disclosure can be used to cover such flexible electronic materials that are repeatedly in a bent state in the electronic device. For example, it can be directly sprayed with a spray liquid to form an electromagnetic shielding film to cover it. Since the formed electromagnetic shielding film has good bending resistance and reliability, it can provide reliable electromagnetic interference shielding for such flexible electronic materials that are repeatedly in a bent state.

[0169] Other embodiments of the present invention will readily occur to those skilled in the art after considering the specification and practicing the invention disclosed herein. This application is intended to cover any variations, uses, or adaptations of the present invention that follow the general principles of the invention and include common knowledge or customary techniques in the art not disclosed herein. The description and examples are to be considered as exemplary only, with the true scope and spirit of the invention being indicated by the following claims.

[0170] It should be understood that the present invention is not limited to the exact construction described above and shown in the drawings, and that various modifications and changes may be made without departing from the scope thereof. The scope of the present invention is limited only by the appended claims.

Claims

1. An electromagnetic shielding film, characterized in that The electromagnetic shielding film comprises: a high molecular polymer and a non-metallic-based conductive material in a preset mass ratio.

2. The electromagnetic shielding film according to claim 1, wherein The preset mass ratio of the non-metal-based conductive material to the high molecular polymer is 1:9 to 1:

1.

3. The electromagnetic shielding film according to claim 2, wherein The electromagnetic shielding effectiveness of the electromagnetic shielding film is 10dB-60dB.

4. The electromagnetic shielding film according to claim 2, wherein The tensile stress of the electromagnetic shielding film is 200 MPa-320 MPa, and the elongation at break of the electromagnetic shielding film is 2.2%-4.4%.

5. The electromagnetic shielding film according to claim 2, wherein The electrical conductivity of the electromagnetic shielding film is 20S / m-120S / m.

6. The electromagnetic shielding film according to claim 2, wherein The density of the electromagnetic shielding film is 1.6 g / cm 3 -2.7g / cm 3 .

7. The electromagnetic shielding film according to claim 1, wherein The high molecular polymer is a water-soluble polymer; The high molecular polymer includes one or more of polyvinyl alcohol, polyacrylamide, polyethylene oxide, waterborne polyurethane, gelatin, cellulose, and modified cellulose.

8. The electromagnetic shielding film according to claim 7, wherein In the electromagnetic shielding film, the high molecular polymer and the non-metal-based conductive material are in a physically mixed state, and the two are connected through hydrogen bonds.

9. The electromagnetic shielding film according to claim 1, wherein The non-metal-based conductive material includes a carbon-containing conductive material; The carbon-containing conductive material includes one or more of graphene, carbon nanotubes, transition metal carbides, transition metal nitrides, transition metal carbonitrides, and conductive carbon black.

10. The electromagnetic shielding film according to claim 1, wherein The thickness of the electromagnetic shielding film is 12 μm-18 μm.

11. The electromagnetic shielding film according to any one of claims 1 to 10, characterized in that: The outer surface of the electromagnetic shielding film includes a hydrophobic layer.

12. The electromagnetic shielding film according to claim 11, wherein The water contact angle of the electromagnetic shielding film including the hydrophobic layer is (90°, 105°).

13. The electromagnetic shielding film according to claim 11, wherein The material of the hydrophobic layer includes polyurethane adhesive or polydimethylsiloxane.

14. A method for manufacturing an electromagnetic shielding film, characterized in that: The production method comprises: Dispersing the high molecular weight polymer in a predetermined solvent to form a first solution; Dispersing a non-metal-based conductive material in the predetermined solvent to form a second solution; mixing the first solution and the second solution in a first preset ratio to obtain a mixed solution; Under a first preset condition, the mixed solution is sprayed on a substrate to obtain the electromagnetic shielding film, which includes the high molecular polymer and the non-metal-based conductive material in a preset mass ratio.

15. The method for manufacturing an electromagnetic shielding film according to claim 14, wherein: The first preset ratio includes: in the mixed solution, the solid content ratio of the non-metal-based conductive material to the high molecular polymer is the preset mass ratio, and the preset mass ratio is 1:9 to 1:

1.

16. The method for manufacturing an electromagnetic shielding film according to claim 14, wherein: The viscosity of the first solution is 40 mPa·s-200 mPa·s; and / or, The mass concentration of the second solution is 30 mg / ml-40 mg / ml.

17. The method for manufacturing an electromagnetic shielding film according to claim 14, wherein: When the non-metal-based conductive material is MXene, the MXene includes one or more of transition metal carbides, transition metal nitrides, and transition metal carbonitrides. The method for forming the second solution includes: adding a first weight of a fluoride salt to a predetermined volume of an acid solution having a predetermined concentration, stirring until the fluoride salt is dissolved, and then adding a second weight of a MAX phase ceramic to the acid solution; Under a second preset condition, stirring the acid solution mixed with the MAX phase ceramic and the fluoride salt to remove the A atomic layer in the MAX phase ceramic to obtain a semi-finished product; The semi-finished product is washed multiple times with deionized water. After the pH of the washing solution is greater than or equal to a preset pH, the semi-finished product is centrifuged, and the supernatant obtained by the centrifugation is used as the second solution containing the MXene.

18. The method for manufacturing an electromagnetic shielding film according to claim 17, wherein: When the fluoride salt comprises lithium fluoride and the MAX phase ceramic comprises Ti3AlC2, the first weight is 5.00 g to 8.00 g and the second weight is 3.13 g to 5.00 g; and / or, When the acid solution includes a hydrochloric acid solution, the preset concentration is 3 mol / L-6 mol / L, and the preset volume is 60 ml-100 ml.

19. The method for manufacturing an electromagnetic shielding film according to claim 17, wherein: The preset pH is 6.

0.

20. The method for manufacturing an electromagnetic shielding film according to claim 17, wherein: The second preset condition includes at least one of the following: The reaction temperature is 32°C-38°C; The reaction time is 22h-26h.

21. The method for manufacturing an electromagnetic shielding film according to claim 14, wherein: The first preset condition includes at least one of the following: Spraying pressure is 1.0MPa-2.7MPa; The spraying speed is 95ml / h-105ml / h.

22. The method for manufacturing an electromagnetic shielding film according to claim 14, wherein: The preset solvent includes one or more of deionized water, methanol, ethanol, and N,N-dimethylformamide.

23. The method for manufacturing an electromagnetic shielding film according to any one of claims 14 to 22, characterized in that: The production method further comprises: preparing a hydrophobic treatment liquid comprising a first component and a second component mixed in a second predetermined ratio; The electromagnetic shielding film is immersed in the hydrophobic treatment liquid and reacted under a third preset condition, so that a hydrophobic layer is formed on the outer surface of the electromagnetic shielding film.

24. The method for manufacturing an electromagnetic shielding film according to claim 23, wherein: The first component comprises acetonitrile and adipic acid polyester polyol, and the second component comprises isocyanate; or The first component includes polydimethylsiloxane prepolymer and a platinum catalyst, and the second component includes vinyl silicone oil and a crosslinking agent.

25. The method for manufacturing an electromagnetic shielding film according to claim 24, wherein: In the first component, the volume ratio of the acetonitrile to the adipic acid polyester polyol is 6:1 to 4:1; and / or, The second preset ratio includes: a volume ratio of the first component to the second component is 9:1 to 3:

1.

26. The method for manufacturing an electromagnetic shielding film according to claim 23, wherein: The third preset condition includes at least one of the following: The reaction temperature is 68°C-72°C; The reaction time is 1.8h-2.2h.

27. An electronic component, characterized in that: The electronic component includes a component body and the electromagnetic shielding film according to any one of claims 1 to 13, wherein the electromagnetic shielding film covers an outer surface of the component body.

28. A structural member, characterized in that: The structural member is made of the electromagnetic shielding film according to any one of claims 1 to 13.

29. An electronic device, characterized in that: The electronic device includes the electronic component according to claim 27 and / or the structural part according to claim 28.

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