Aramid paper with high mechanical property and electromagnetic shielding property as well as preparation method and application of aramid paper

Abstract

The invention belongs to the technical field of aramid paper, and particularly relates to aramid paper with high mechanical performance and electromagnetic shielding performance as well as a preparation method and application of the aramid paper. According to the aramid paper with the high mechanical performance and the electromagnetic shielding performance, the electromagnetic shielding layer is bonded to the surface of the aramid paper, so that the aramid paper has the mechanical performance such as high tensile strength and the electromagnetic shielding performance such as low dielectric constant; meanwhile, the composition in the electromagnetic shielding layer is improved, an oriented carbon-based conductive material and a non-oriented magnetic material are compounded, and the non-oriented magnetic material is filled in a gap formed by intersection of the oriented carbon-based conductive material, so that the overall electromagnetic shielding performance of the electromagnetic shielding layer can be improved; therefore, the technical problem that an electromagnetic shielding material in the prior art does not have high mechanical performance and electromagnetic shielding performance at the same time is solved.

Description

Technical Field

[0001] The present application belongs to the technical field of aramid paper, and in particular relates to aramid paper having both high mechanical properties and electromagnetic shielding properties, and a preparation method and application thereof. Background Art

[0002] With the development of social economy, electronic equipment is increasingly used in people's life and work. However, electronic equipment will generate electromagnetic radiation during operation, which may have adverse effects on the health of operators. At the same time, electromagnetic radiation between electronic equipment may also cause risks such as leakage of communication information after being intercepted or loss of communication information. Therefore, electromagnetic shielding interference of electronic equipment is very important.

[0003] At present, electromagnetic shielding is mainly based on metal conductive materials and magnetic materials. By applying metal particle coating or magnetic material coating on the surface of electronic equipment by spraying and brushing, an electromagnetic shielding layer is formed to absorb, conduct and attenuate electromagnetic waves, thereby shielding electromagnetic wave interference. However, the density of the electromagnetic shielding layer formed by metal conductive materials and magnetic materials is usually high, which increases the weight of the electronic equipment. In addition to metal conductive materials and magnetic materials, inorganic conductive materials are also added to ordinary fiber paper to make electromagnetic shielding materials, which reduces the density of electromagnetic shielding materials. However, this type of electromagnetic shielding material has poor mechanical properties such as flexibility and is not durable. In addition, the electromagnetic shielding function of this type of electromagnetic shielding material needs to be improved, and it does not have high mechanical properties and electromagnetic shielding performance at the same time. Summary of the invention

[0004] In view of this, the present application provides aramid paper having both high mechanical properties and electromagnetic shielding properties, as well as a preparation method and application, to solve the technical problem in the prior art that electromagnetic shielding materials do not have both high mechanical properties and electromagnetic shielding properties.

[0005] In a first aspect, the present application provides an aramid paper having both high mechanical properties and electromagnetic shielding properties, comprising aramid paper and an electromagnetic shielding layer;

[0006] The electromagnetic shielding layer is bonded to the surface of the aramid paper.

[0007] Preferably, the electromagnetic shielding layer comprises an oriented carbon-based conductive material and a non-oriented magnetic material.

[0008] Preferably, the oriented carbon-based conductive material is selected from carbon nanotubes;

[0009] The non-oriented magnetic material is selected from at least one of carbonyl iron, ferrite, and sendust.

[0010] Preferably, the carbon nanotubes have a length of 0.5 to 50 μm and a diameter of 10 to 100 nm;

[0011] The particle size of the non-oriented magnetic material is 0.5-5 μm.

[0012] Preferably, calculated in parts by mass, the electromagnetic shielding layer includes 0.5-2 parts by mass of oriented carbon-based conductive material, 0.1-1 parts by mass of non-oriented magnetic material and 1-20 parts by mass of waterborne polyurethane.

[0013] The second aspect of the present application provides a method for preparing aramid paper having both high mechanical properties and electromagnetic shielding properties, which can prepare the aramid paper having both high mechanical properties and electromagnetic shielding properties described in the first aspect, and the preparation method comprises the steps of:

[0014] Step S1, uniformly stirring an oriented carbon-based conductive material, a non-oriented magnetic material, an aqueous polyurethane, a dispersant and water to obtain an electromagnetic shielding ink;

[0015] Step S2, coating the electromagnetic shielding ink on the surface of the aramid paper to obtain the aramid paper coated with the electromagnetic shielding layer;

[0016] Step S3, hot-pressing the aramid paper coated with the electromagnetic shielding layer to obtain aramid paper having both high mechanical properties and electromagnetic shielding properties.

[0017] Preferably, in step S1, calculated in parts by mass, 0.5-2 parts by mass of oriented carbon-based conductive material, 0.1-1 parts by mass of non-oriented magnetic material, 1-20 parts by mass of waterborne polyurethane, 0.5-2 parts by mass of dispersant and 75-90 parts by mass of water are included.

[0018] Preferably, in step S2, in the aramid paper coated with the electromagnetic shielding layer, the mass ratio of the electromagnetic shielding ink to the aramid paper is 100-1000:100.

[0019] Preferably, in step S3, the hot pressing temperature is 200-300° C., the pressure is 0.2-1 MPa, and the roller speed is 2-10 m / min.

[0020] A third aspect of the present application provides an application of aramid paper having both high mechanical properties and electromagnetic shielding properties in electronic devices.

[0021] In summary, the present application provides aramid paper having both high mechanical properties and electromagnetic shielding properties, as well as a preparation method and application. The aramid paper having both high mechanical properties and electromagnetic shielding properties provided by the present application includes aramid paper and an electromagnetic shielding layer, and the electromagnetic shielding layer is bonded to the surface of the aramid paper; the electromagnetic shielding layer can provide the function of shielding electromagnetic wave interference, and the aramid paper has high strength, thereby solving the technical problem in the prior art that the electromagnetic shielding material does not have both high mechanical properties and electromagnetic shielding properties. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the specific implementation methods of the present application or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0023] Figure 1 A schematic flow chart of a method for preparing aramid paper having both high mechanical properties and electromagnetic shielding properties provided in Example 1 of the present application. DETAILED DESCRIPTION

[0024] The present application provides aramid paper having both high mechanical properties and electromagnetic shielding properties, as well as a preparation method and application thereof, to solve the technical problem in the prior art that electromagnetic shielding materials do not have both high mechanical properties and electromagnetic shielding properties.

[0025] The technical solution of the present application will be described clearly and completely below in conjunction with the accompanying drawings. Obviously, the described embodiments are part of the embodiments of the present application, rather than all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present application.

[0026] In view of the defect that current electromagnetic shielding materials do not have both high mechanical properties and electromagnetic shielding properties, the present application provides an aramid paper with both high mechanical properties and electromagnetic shielding properties; the composition includes aramid paper and an electromagnetic shielding layer, and the electromagnetic shielding layer is bonded to the surface of the aramid paper; the electromagnetic shielding layer can provide the function of shielding electromagnetic wave interference, and aramid paper, also known as polyaramid fiber paper, is prepared from aramid fiber through a wet molding process. Aramid paper can provide high tensile strength, so that the aramid paper provided by the present application has both high mechanical properties and electromagnetic shielding properties, overcoming the defect that current electromagnetic shielding materials do not have both high mechanical properties and electromagnetic shielding properties.

[0027] Preferably, the present application discloses a magnetic shielding material in aramid paper having both high mechanical properties and electromagnetic shielding properties, wherein the electromagnetic shielding layer comprises oriented carbon-based conductive materials such as carbon nanotubes and non-oriented magnetic materials such as carbonyl iron, ferrite, and sendust; carbon nanotubes are fibrous carbon-based conductive materials, which will have directionality when on the surface of aramid paper, showing a lateral distribution, longitudinal distribution or oblique distribution, while carbonyl iron, ferrite and sendust are granular magnetic materials, which have no directionality when on the surface of aramid paper, and can be filled in the gaps between the transversely, longitudinally or obliquely distributed carbon nanotubes, exerting an electromagnetic shielding function in the gap space, thereby improving the weak electromagnetic shielding function of the gap space, and improving the overall electromagnetic shielding performance of the electromagnetic shielding layer.

[0028] Preferably, the size of the electromagnetic shielding material in the aramid paper of the present application having both high mechanical properties and electromagnetic shielding properties is as follows: the length of the carbon nanotubes is 0.5~50μm, and the diameter is 10~100nm; the particle size of the non-oriented magnetic material is 0.5~5μm; wherein the length of the carbon nanotubes is 0.5~50μm, and the diameter is 10~100nm, and the particle size of the non-oriented magnetic material is 0.5~5μm. The size range of the electromagnetic shielding material is relatively large, so that the overall electromagnetic shielding performance of the electromagnetic shielding layer can be regulated in a relatively large range.

[0029] Preferably, the composition of the raw materials in the aramid paper having both high mechanical properties and electromagnetic shielding properties in the present application includes 0.5-2 parts by mass of oriented carbon-based conductive material, 0.1-1 parts by mass of non-oriented magnetic material and 1-20 parts by mass of aqueous polyurethane; the aqueous polyurethane plays the role of bonding the electromagnetic shielding material to the surface of the aramid paper.

[0030] Preferably, the present application provides a method for preparing aramid paper with both high mechanical properties and electromagnetic shielding properties. The preparation method firstly stirs a carbon-based conductive material, a non-oriented magnetic material, an aqueous polyurethane, a dispersant and water to obtain an electromagnetic shielding ink, and then applies the electromagnetic shielding ink to the surface of the aramid paper and hot presses it to obtain the aramid paper with both high mechanical properties and electromagnetic shielding properties. In the process of preparing the electromagnetic shielding ink, the addition of a dispersant is beneficial to the full dispersion of carbon-based conductive materials such as carbon nanotubes and non-oriented magnetic materials such as carbonyl iron, which is beneficial to the subsequent electromagnetic shielding materials being evenly dispersed on the surface of the aramid paper and not easy to agglomerate. The coating process used in the process of applying the electromagnetic shielding ink is beneficial to the uniform distribution of carbon-based conductive materials such as carbon nanotubes and non-oriented magnetic materials such as carbonyl iron on the surface of the aramid paper. The hot pressing process can effectively and stably bond carbon-based conductive materials such as carbon nanotubes and non-oriented magnetic materials such as carbonyl iron to the surface of the aramid paper, thereby improving the durability of the aramid paper with both high mechanical properties and electromagnetic shielding properties provided by the present application.

[0031] Preferably, the present application provides the use of aramid paper having both high mechanical properties and electromagnetic shielding properties in electronic devices, which can enable the electronic devices to have better electromagnetic shielding functions and improve the health problems and information security defects that may be caused by electromagnetic radiation from electronic devices.

[0032] The aramid paper with both high mechanical properties and electromagnetic shielding properties provided by the present application will be specifically described below in combination with the preparation method and performance testing.

[0033] Example 1

[0034] Example 1 of the present application provides a method for preparing aramid paper having both high mechanical properties and electromagnetic shielding properties; the preparation method includes the steps of preparing electromagnetic shielding ink, coating the electromagnetic shielding ink, and hot pressing.

[0035] Among them, the steps of preparing electromagnetic shielding ink include: mixing 98g of water and 0.5g of dispersant FS-17 and stirring until the dispersant is dissolved, then adding 0.5g of carbon nanotubes (length 1μm, diameter 10nm) into the dispersion, after ultrasonic treatment, adding 1g of water-based polyurethane into the dispersion, and stirring until completely mixed to obtain electromagnetic shielding ink.

[0036] The steps of applying electromagnetic shielding ink include: firstly mixing 450g of meta-aramid pulp with a beating degree of 60°SR with 550g of aramid short-cut fibers, and preparing meta-aramid paper (paper weight 40g / m 2 ), and then use a coating machine to coat the electromagnetic shielding ink on the surface of the meta-aramid paper, and control the electromagnetic shielding ink flow of the coating machine so that the mass ratio of the electromagnetic shielding ink to the aramid paper is 200:100, that is, 200g of electromagnetic shielding ink is coated on the surface of 2.5 square meters of aramid paper, and 1g of carbon nanotubes is distributed on the surface of 2.5 square meters of aramid paper.

[0037] The hot pressing step includes: using a hot press machine to hot press the aramid paper coated with electromagnetic shielding ink at a temperature of 270° C., a pressure of 0.5 MPa, and a roller speed of 5 m / min to obtain aramid paper with both high mechanical properties and electromagnetic shielding properties.

[0038] Example 2

[0039] Example 2 of the present application provides a method for preparing aramid paper having both high mechanical properties and electromagnetic shielding properties; the preparation method includes the steps of preparing electromagnetic shielding ink, coating the electromagnetic shielding ink, and hot pressing.

[0040] Among them, the steps of preparing electromagnetic shielding ink include: mixing 98g of water and 0.5g of dispersant FS-17 and stirring until the dispersant is dissolved, then adding 0.5g of carbon nanotubes (length 1μm, diameter 10nm) into the dispersion, after ultrasonic treatment, adding 3g of water-based polyurethane into the dispersion, and stirring until completely mixed to obtain electromagnetic shielding ink.

[0041] The steps of applying electromagnetic shielding ink include: firstly mixing 450g of meta-aramid pulp with a beating degree of 60°SR with 550g of aramid short-cut fibers, and preparing meta-aramid paper (paper weight 40g / m 2), and then use a coating machine to coat the electromagnetic shielding ink on the surface of the meta-aramid paper, and control the electromagnetic shielding ink flow of the coating machine so that the mass ratio of the electromagnetic shielding ink to the aramid paper is 600:100, that is, 600g of electromagnetic shielding ink is coated on the surface of 2.5 square meters of aramid paper, and 3g of carbon nanotubes are distributed on the surface of 2.5 square meters of aramid paper.

[0042] The hot pressing step includes: using a hot press machine to hot press the aramid paper coated with electromagnetic shielding ink at a temperature of 270° C., a pressure of 0.5 MPa, and a roller speed of 5 m / min to obtain aramid paper with both high mechanical properties and electromagnetic shielding properties.

[0043] Example 3

[0044] Example 3 of the present application provides a method for preparing aramid paper having both high mechanical properties and electromagnetic shielding properties; the preparation method includes the steps of preparing electromagnetic shielding ink, coating the electromagnetic shielding ink, and hot pressing.

[0045] Among them, the steps of preparing electromagnetic shielding ink include: mixing 98g of water and 0.5g of dispersant FS-17 and stirring until the dispersant is dissolved, then adding 0.5g of carbon nanotubes (length 5μm, diameter 10nm) into the dispersion, after ultrasonic treatment, adding 3g of water-based polyurethane into the dispersion, and stirring until completely mixed to obtain electromagnetic shielding ink.

[0046] The steps of applying electromagnetic shielding ink include: firstly mixing 450g of meta-aramid pulp with a beating degree of 60°SR with 550g of aramid short-cut fibers, and preparing meta-aramid paper (paper weight 40g / m 2 ), and then use a coating machine to coat the electromagnetic shielding ink on the surface of the meta-aramid paper, and control the electromagnetic shielding ink flow of the coating machine so that the mass ratio of the electromagnetic shielding ink to the aramid paper is 1000:100, that is, 1000g of electromagnetic shielding ink is coated on the surface of 2.5 square meters of aramid paper, and 5g of carbon nanotubes are distributed on the surface of 2.5 square meters of aramid paper.

[0047] The hot pressing step includes: using a hot press machine to hot press the aramid paper coated with electromagnetic shielding ink at a temperature of 300° C., a pressure of 0.5 MPa, and a roller speed of 5 m / min to obtain aramid paper with both high mechanical properties and electromagnetic shielding properties.

[0048] Example 4

[0049] Example 4 of the present application provides a method for preparing aramid paper having both high mechanical properties and electromagnetic shielding properties; the preparation method includes the steps of preparing electromagnetic shielding ink, coating the electromagnetic shielding ink, and hot pressing.

[0050] Among them, the steps of preparing electromagnetic shielding ink include: mixing 98g of water and 0.5g of dispersant FS-17 and stirring until the dispersant is dissolved, then adding 0.5g of carbon nanotubes (length 20μm, diameter 10nm) into the dispersion, after ultrasonic treatment, adding 5g of water-based polyurethane into the dispersion, and stirring until completely mixed to obtain electromagnetic shielding ink.

[0051] The steps of applying electromagnetic shielding ink include: firstly mixing 450g of meta-aramid pulp with a beating degree of 60°SR with 550g of aramid short-cut fibers, and preparing meta-aramid paper (paper weight 40g / m 2 ), and then use a coating machine to coat the electromagnetic shielding ink on the surface of the meta-aramid paper, and control the electromagnetic shielding ink flow of the coating machine so that the mass ratio of the electromagnetic shielding ink to the aramid paper is 600:100, that is, 600g of electromagnetic shielding ink is coated on the surface of 2.5 square meters of aramid paper, and 3g of carbon nanotubes are distributed on the surface of 2.5 square meters of aramid paper.

[0052] The hot pressing step includes: using a hot press machine to hot press the aramid paper coated with electromagnetic shielding ink at a temperature of 300° C., a pressure of 0.5 MPa, and a roller speed of 5 m / min to obtain aramid paper with both high mechanical properties and electromagnetic shielding properties.

[0053] Example 5

[0054] Example 5 of the present application provides a method for preparing aramid paper having both high mechanical properties and electromagnetic shielding properties; the preparation method includes the steps of preparing electromagnetic shielding ink, coating the electromagnetic shielding ink, and hot pressing.

[0055] Among them, the steps of preparing electromagnetic shielding ink include: mixing 97.75g of water and 0.5g of dispersant FS-17 and stirring until the dispersant is dissolved, then adding 0.5g of carbon nanotubes (length 20μm, diameter 10nm) into the dispersion, after ultrasonic treatment, adding 5g of water-based polyurethane and 0.25g of carbonyl iron powder into the dispersion, and stirring until completely mixed to obtain electromagnetic shielding ink.

[0056] The steps of applying electromagnetic shielding ink include: firstly mixing 450g of meta-aramid pulp with a beating degree of 60°SR with 550g of aramid short-cut fibers, and preparing meta-aramid paper (paper weight 40g / m 2 ), and then use a coating machine to coat the electromagnetic shielding ink on the surface of the meta-aramid paper, and control the electromagnetic shielding ink flow of the coating machine so that the mass ratio of the electromagnetic shielding ink to the aramid paper is 1000:100, that is, 1000g of the electromagnetic shielding ink is coated on the surface of 2.5 square meters of the aramid paper, and 5g of carbon nanotubes and 2.5g of carbonyl iron powder are distributed on the surface of 2.5 square meters of the aramid paper.

[0057] The hot pressing step includes: using a hot press machine to hot press the aramid paper coated with electromagnetic shielding ink at a temperature of 300° C., a pressure of 0.5 MPa, and a roller speed of 5 m / min to obtain aramid paper with both high mechanical properties and electromagnetic shielding properties.

[0058] Example 6

[0059] Example 6 of the present application provides a method for preparing aramid paper having both high mechanical properties and electromagnetic shielding properties; the preparation method includes the steps of preparing electromagnetic shielding ink, coating the electromagnetic shielding ink, and hot pressing.

[0060] Among them, the steps of preparing electromagnetic shielding ink include: mixing 97.9g of water and 0.5g of dispersant FS-17 and stirring until the dispersant is dissolved, then adding 0.5g of carbon nanotubes (length 20μm, diameter 10nm) into the dispersion, after ultrasonic treatment, adding 5g of water-based polyurethane and 0.1g of carbonyl iron powder into the dispersion, and stirring until completely mixed to obtain electromagnetic shielding ink.

[0061] The steps of applying electromagnetic shielding ink include: firstly mixing 450g of meta-aramid pulp with a beating degree of 60°SR with 550g of aramid short-cut fibers, and preparing meta-aramid paper (paper weight 40g / m 2 ), and then use a coating machine to coat the electromagnetic shielding ink on the surface of the meta-aramid paper, and control the electromagnetic shielding ink flow of the coating machine so that the mass ratio of the electromagnetic shielding ink to the aramid paper is 600:100, that is, 600g of electromagnetic shielding ink is coated on the surface of 2.5 square meters of aramid paper, and 3g of carbon nanotubes and 0.6g of carbonyl iron powder are distributed on the surface of 2.5 square meters of aramid paper.

[0062] The hot pressing step includes: using a hot press machine to hot press the aramid paper coated with electromagnetic shielding ink at a temperature of 300° C., a pressure of 0.5 MPa, and a roller speed of 5 m / min to obtain aramid paper with both high mechanical properties and electromagnetic shielding properties.

[0063] Experimental Example 1

[0064] In this Experimental Example 1, the mechanical properties and electromagnetic shielding performance of the aramid paper with high mechanical properties and electromagnetic shielding performance provided by Examples 1-6 were tested. The test results are shown in Table 1.

[0065] Table 1: Mechanical properties and electromagnetic shielding performance test results

[0066]

[0067] It can be seen from the test results in Table 1 that the tensile strength of the aramid paper with both high mechanical properties and electromagnetic shielding properties provided in Examples 1-6 is between 3.69 and 4.78 kN / m, indicating that it has strong mechanical strength, and the electromagnetic shielding performance data such as dielectric constant are also good, and it has good electromagnetic shielding performance.

[0068] Further comparison of the electromagnetic shielding performance revealed that the dielectric constant of the aramid paper with both high mechanical properties and electromagnetic shielding performance provided in Examples 1-3 gradually decreased, indicating that the electromagnetic shielding performance gradually increased. This may be because the amount of carbon nanotubes added in Examples 1-3 gradually increased, thereby improving the electromagnetic shielding performance of the aramid paper.

[0069] By comparing Example 2 and Example 6, Example 3 and Example 5, and Example 3 and Example 6, it is found that when oriented carbon-based conductive material and non-oriented magnetic material are added at the same time, since the non-oriented magnetic material can fill the pores between the carbon-based conductive materials distributed in the transverse, longitudinal or oblique directions, the dielectric constant is gradually lower and the electromagnetic shielding performance is gradually stronger; and when 2.5g of carbon nanotubes and 0.6g of carbonyl iron powder are distributed on the surface of 2.5 square meters of aramid paper, its electromagnetic shielding performance can be stronger than distributing 5g of carbon nanotubes on the surface of 2.5 square meters of aramid paper.

[0070] Although the aramid paper with both high mechanical properties and electromagnetic shielding properties provided in Example 4 and Example 3 has the same amount of carbon nanotubes added, the electromagnetic shielding property is stronger because the aramid paper provided in Example 4 contains carbon nanotubes with a larger aspect ratio.

[0071] The above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, a person skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some or all of the technical features thereof may be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present application.

Claims

1. Aramid paper having both high mechanical properties and electromagnetic shielding properties, characterized in that: Includes aramid paper and electromagnetic shielding layer; The electromagnetic shielding layer is bonded to the surface of the aramid paper.

2. The aramid paper having both high mechanical properties and electromagnetic shielding properties according to claim 1, characterized in that: The electromagnetic shielding layer includes an oriented carbon-based conductive material and a non-oriented magnetic material.

3. The aramid paper having both high mechanical properties and electromagnetic shielding properties according to claim 2, characterized in that: The oriented carbon-based conductive material is selected from carbon nanotubes; The non-oriented magnetic material is selected from at least one of carbonyl iron, ferrite, and sendust.

4. The aramid paper having both high mechanical properties and electromagnetic shielding properties according to claim 3, characterized in that: The carbon nanotubes have a length of 0.5-50 μm and a diameter of 10-100 nm; The particle size of the non-oriented magnetic material is 0.5-5 μm.

5. The aramid paper having both high mechanical properties and electromagnetic shielding properties according to claim 3, characterized in that: Calculated in parts by mass, the electromagnetic shielding layer includes 0.5 to 2 parts by mass of oriented carbon-based conductive material, 0.1 to 1 parts by mass of non-oriented magnetic material and 1 to 20 parts by mass of waterborne polyurethane.

6. A method for preparing aramid paper having both high mechanical properties and electromagnetic shielding properties as claimed in any one of claims 1 to 4, characterized in that: Includes steps: Step S1, uniformly stirring an oriented carbon-based conductive material, a non-oriented magnetic material, an aqueous polyurethane, a dispersant and water to obtain an electromagnetic shielding ink; Step S2, coating the electromagnetic shielding ink on the surface of the aramid paper to obtain the aramid paper coated with the electromagnetic shielding layer; Step S3, hot-pressing the aramid paper coated with the electromagnetic shielding layer to obtain aramid paper having both high mechanical properties and electromagnetic shielding properties.

7. The method for preparing aramid paper having both high mechanical properties and electromagnetic shielding properties according to claim 6, characterized in that: In step S1, calculated by weight, 0.5-2 weight parts of oriented carbon-based conductive material, 0.1-1 weight parts of non-oriented magnetic material, 1-20 weight parts of waterborne polyurethane, 0.5-2 weight parts of dispersant and 75-90 weight parts of water are included.

8. The method for preparing aramid paper having both high mechanical properties and electromagnetic shielding properties according to claim 6, characterized in that: In step S2, in the aramid paper coated with the electromagnetic shielding layer, the mass ratio of the electromagnetic shielding ink to the aramid paper is 1-10:

100.

9. The method for preparing aramid paper having both high mechanical properties and electromagnetic shielding properties according to claim 6, characterized in that: In step S3, the hot pressing temperature is 200-300° C., the pressure is 0.2-1 MPa, and the roller speed is 2-10 m / min.

10. Application of the aramid paper having high mechanical properties and electromagnetic shielding properties as claimed in any one of claims 1 to 4 in electronic devices.

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