Broadband electromagnetic shielding coating based on nano titanium dioxide as well as preparation method and application of broadband electromagnetic shielding coating

Abstract

The invention belongs to the technical field of electromagnetic shielding coatings, and particularly discloses a broadband electromagnetic shielding coating based on nano titanium dioxide as well as a preparation method and application of the broadband electromagnetic shielding coating. The broadband electromagnetic shielding coating comprises a component A and a component B, the component A comprises 40-60 parts of water-borne epoxy resin, 5-15 parts of nano titanium dioxide, 10-30 parts of silver-coated copper powder, 3-10 parts of a conductive polymer, 1-5 parts of silver-coated carbon fiber, 0.5-1 part of a coupling agent, 5-10 parts of a diluent and 0.1-5 parts of an auxiliary agent; the component B comprises a curing agent. During use, the component A and the component B are mixed according to the mass ratio of 100: (15-25), and the broadband electromagnetic shielding coating is obtained through coating. The nano titanium dioxide can form a conductive network with other components, the electromagnetic shielding effectiveness is improved through the relatively high dielectric constant of the nano titanium dioxide, and the weather resistance and the self-cleaning capability of the material can also be improved; the coating can effectively shield electromagnetic interference of various frequencies, and has excellent shielding effectiveness.

Description

Technical Field

[0001] The present invention relates to the technical field of electromagnetic shielding coatings, and in particular to a broadband electromagnetic shielding coating based on nano-titanium dioxide, and a preparation method and application thereof. Background Art

[0002] With the rapid development of new-generation information technologies such as 5G communications, satellite communications, and the Internet of Things, the frequency range of electromagnetic waves is expanding, and the electromagnetic environment, from low frequencies to high frequencies (such as millimeter waves and terahertz waves), is becoming increasingly complex. At the same time, electromagnetic interference (EMI) is becoming increasingly prominent, not only affecting the normal operation of electronic equipment but also posing a serious threat to communication quality, information security, and human health. Therefore, the development of materials that can effectively shield against broadband electromagnetic interference has become an important research direction in the fields of materials science and electronic information.

[0003] Traditional electromagnetic shielding materials primarily rely on metals (such as copper, aluminum, and their alloys) to achieve shielding effects by reflecting electromagnetic waves. However, these materials have the following limitations: 1. They are high in density, making them difficult to meet the lightweighting requirements of modern electronic devices; 2. They are susceptible to corrosion, resulting in a limited service life in complex environments; 3. Their shielding effectiveness against high-frequency electromagnetic waves is significantly reduced, making it difficult to meet the stringent broadband electromagnetic shielding requirements of high-end applications such as 5G communications and satellite communications; and 4. They have a limited functionality.

[0004] In high-end applications such as 5G communications and satellite communications, electromagnetic shielding materials must not only have broadband shielding performance but also meet requirements such as lightweight, flexibility, and weather resistance. Traditional metal-based materials have difficulty meeting these requirements.

[0005] In recent years, nanomaterials have demonstrated tremendous potential in electromagnetic shielding due to their unique physical and chemical properties. Nano-titanium dioxide, a wide-bandgap semiconductor material, boasts excellent photocatalytic performance, chemical stability, and environmental friendliness, and has been widely used in energy, environmental protection, and medical fields. Research has shown that nano-TiO2 can achieve electromagnetic shielding by absorbing and scattering electromagnetic waves. However, single nano-TiO2 materials suffer from poor conductivity and imperfect impedance matching, making them difficult to meet the requirements of broadband electromagnetic shielding.

[0006] In addition, the surface of traditional electromagnetic shielding materials easily absorbs dust and pollutants, which not only affects their appearance and service life, but also reduces their electromagnetic shielding performance.

[0007] To sum up, how to disclose a broadband electromagnetic shielding coating based on nano-titanium dioxide and its preparation method and application to meet the needs of high-end application fields, improve the broadband shielding effect of the shielding coating, and achieve functional diversification is a difficult problem that needs to be solved urgently in this field. Summary of the Invention

[0008] In view of this, the present invention provides a broadband electromagnetic shielding coating based on nano-titanium dioxide and its preparation method and application, in order to solve the problem that existing electromagnetic shielding coatings cannot meet the needs of high-end application fields and have poor broadband shielding effect.

[0009] In order to achieve the above object, the present invention adopts the following technical solutions:

[0010] A broadband electromagnetic shielding coating based on nano-titanium dioxide, comprising component A and component B;

[0011] Wherein, component A includes the following components in parts by mass:

[0012] 40-60 parts of waterborne epoxy resin, 5-15 parts of nano-titanium dioxide, 10-30 parts of silver-coated copper powder, 3-10 parts of conductive polymer, 1-5 parts of silver-coated carbon fiber, 0.5-1 part of coupling agent, 5-10 parts of diluent, and 0.1-5 parts of additives;

[0013] Component B includes a curing agent.

[0014] Preferably, the waterborne epoxy resin includes bisphenol A epoxy resin and / or bisphenol F epoxy resin.

[0015] Preferably, the particle size of the nano titanium dioxide is 10 to 100 nm.

[0016] Preferably, the particle size of the silver-coated copper powder is 10 to 30 μm; the mass content of silver in the silver-coated copper powder is 18 to 22%.

[0017] Preferably, the conductive polymer includes one or more of polyaniline, polypyrrole, polythiophene and polyethylenedioxythiophene.

[0018] Preferably, the length of the silver-coated carbon fiber is 80 to 1000 μm.

[0019] Preferably, the coupling agent includes an aminosilane coupling agent and / or a titanate coupling agent;

[0020] The diluent includes water;

[0021] The auxiliary agent includes one or more of a dispersant, a defoaming agent, a leveling agent and a thixotropic agent.

[0022] Another object of the present invention is to provide a method for preparing a broadband electromagnetic shielding coating based on nano-titanium dioxide, wherein the method for preparing component A of the broadband electromagnetic shielding coating based on nano-titanium dioxide comprises the following steps:

[0023] Fully mixing waterborne epoxy resin, nano-titanium dioxide, silver-coated copper powder, conductive polymer, silver-coated carbon fiber, coupling agent, diluent, and additives to obtain component A;

[0024] The B component includes a curing agent;

[0025] When used, the mass ratio of component A to component B is 100:15-25.

[0026] Another object of the present invention is to provide an application of a broadband electromagnetic shielding coating based on nano-titanium dioxide in the preparation of electromagnetic shielding materials.

[0027] It can be seen from the above technical solutions that compared with the prior art, the present invention has the following beneficial effects:

[0028] 1. This invention can effectively shield electromagnetic interference of various frequencies (30MHz to 10GHz), demonstrating high shielding effectiveness. Furthermore, it has light density, good flexibility, good weather resistance, and self-cleaning function. It can meet the stringent requirements for broadband electromagnetic shielding in high-end fields such as 5G base stations and satellite communication ground stations.

[0029] 2. The electromagnetic shielding coating disclosed in the present invention includes nano-titanium dioxide, silver-coated copper powder, conductive polymer and silver-coated carbon fiber. The particle sizes of nano-titanium dioxide and silver-coated copper powder are different, and there are two particle sizes, large and small, which can enhance the filling density and improve the mechanical properties. The small particle size component can fill micropores and defects and improve the corrosion resistance; nano-titanium dioxide and silver-coated copper powder can also form a conductive network with silver-coated carbon fiber on the basis of conductive polymer. The conductive network can reflect and absorb electromagnetic waves and convert them into heat energy, thereby reducing electromagnetic interference; the conductive polymer can optimize the conductive network and improve the shielding effectiveness.

[0030] 3. Nano-titanium dioxide has a high dielectric constant, effectively absorbing and attenuating electromagnetic waves, enhancing the material's electromagnetic shielding effectiveness. Its large specific surface area and good dispersibility enhance its interaction with electromagnetic waves, resulting in uniform dispersion and conducive to the formation of a conductive network. Furthermore, it improves the material's weather resistance and self-cleaning capabilities, extending the coating's service life. DETAILED DESCRIPTION

[0031] The invention provides a broadband electromagnetic shielding coating based on nano titanium dioxide, comprising an A component and a B component.

[0032] In the present invention, component A includes the following components in parts by mass:

[0033] 40-60 parts of waterborne epoxy resin, 5-15 parts of nano titanium dioxide, 10-30 parts of silver-coated copper powder, 3-10 parts of conductive polymer, 1-5 parts of silver-coated carbon fiber, 0.5-1 part of coupling agent, 5-10 parts of diluent, and 0.1-5 parts of auxiliary agent; under the mass ratio of the present invention, the addition amount of waterborne epoxy resin can be specifically 42 parts, 45 parts, 48 parts, 50 parts, 52 parts, 55 parts, and 58 parts, the addition amount of nano titanium dioxide can be specifically 6 parts, 8 parts, 10 parts, 12 parts, and 14 parts, and the addition amount of silver-coated copper powder can be specifically 12 parts, 15 parts, and 1 8 parts, 20 parts, 22 parts, 25 parts, 28 parts, the addition amount of the conductive polymer can be specifically 4 parts, 5 parts, 6 parts, 7 parts, 8 parts, 9 parts, the addition amount of the silver-coated carbon fiber can be specifically 1.5 parts, 2 parts, 2.5 parts, 3 parts, 3.5 parts, 4 parts, 4.5 parts, the addition amount of the coupling agent can be specifically 0.6 parts, 0.7 parts, 0.8 parts, 0.9 parts, the addition amount of the diluent can be specifically 6 parts, 7 parts, 8 parts, 9 parts, and the addition amount of the auxiliary agent can be specifically 0.5 parts, 1 part, 1.5 parts, 2 parts, 2.5 parts, 3 parts, 3.5 parts, 4 parts, 4.5 parts,

[0034] In the present invention, component B includes a curing agent, which may be one or more of an amine curing agent, an acid anhydride curing agent, and a polymer curing agent.

[0035] In the present invention, the water-based epoxy resin includes bisphenol A epoxy resin and / or bisphenol F epoxy resin. The broadband electromagnetic shielding coating obtained by the present invention has good flexibility.

[0036] In the present invention, the particle size of the nano titanium dioxide is 10 to 100 nm, specifically 20 nm, 40 nm, 50 nm, 60 nm, or 80 nm.

[0037] In the present invention, the particle size of the silver-coated copper powder is 10 to 30 μm, specifically 12 μm, 15 μm, 18 μm, 20 μm, 22 μm, 25 μm, and 28 μm; the mass content of silver in the silver-coated copper powder is 18 to 22%, specifically 18.5%, 19%, 19.5%, 20%, 20.5%, 21%, and 21.5%.

[0038] In the present invention, the conductive polymer includes one or more of polyaniline, polypyrrole, polythiophene and polyethylenedioxythiophene.

[0039] In the present invention, the length of the silver-coated carbon fiber is 80-1000 μm, specifically 100 μm, 200 μm, 400 μm, 500 μm, 600 μm, or 800 μm.

[0040] In the present invention, the coupling agent includes an aminosilane coupling agent and / or a titanate coupling agent.

[0041] In the present invention, the diluent includes water.

[0042] In the present invention, the auxiliary agent includes one or more of a dispersant, a defoaming agent, a leveling agent and a thixotropic agent.

[0043] The present invention also provides a method for preparing a broadband electromagnetic shielding coating based on nano-titanium dioxide. The method for preparing component A of the broadband electromagnetic shielding coating based on nano-titanium dioxide includes the following steps: fully mixing water-based epoxy resin, nano-titanium dioxide, silver-coated copper powder, conductive polymer, silver-coated carbon fiber, coupling agent, diluent, and additive to obtain component A; the component B includes a curing agent.

[0044] In the present invention, when used, the mass ratio of component A to component B is 100:15-25, preferably 100:18-22, and more preferably 100:20.

[0045] The present invention also provides an application of a broadband electromagnetic shielding coating based on nano-titanium dioxide in the preparation of electromagnetic shielding materials.

[0046] The following is a clear and complete description of the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of the present invention.

[0047] Example 1

[0048] Nano-titanium dioxide with a particle size of 50 to 100 nm, silver-coated copper powder with a particle size of 10 to 15 μm, and silver-coated carbon fiber with a length of 100 to 500 μm are prepared for use;

[0049] Mix 50 parts of bisphenol A epoxy resin with 6 parts of water, then add 10 parts of nano-titanium dioxide, 20 parts of silver-coated copper powder, 8 parts of polyaniline / polypyrrole (mass ratio 1:1), 4 parts of silver-coated carbon fiber, 1 part of aminosilane coupling agent, 2 parts of nano-silica dispersant, 1.5 parts of defoaming agent BYK-022, and 1 part of leveling agent BYK-358N, and stir thoroughly to obtain component A.

[0050] Ethylenediamine is used as component B.

[0051] Component A and component B are mixed in a mass ratio of 100:25 and sprayed on the PET surface to obtain a broadband electromagnetic shielding coating.

[0052] Example 2

[0053] Nano-titanium dioxide with a particle size of 50 to 100 nm, silver-coated copper powder with a particle size of 10 to 15 μm, and silver-coated carbon fiber with a length of 100 to 500 μm are prepared for use;

[0054] Mix 60 parts of bisphenol A epoxy resin with 10 parts of diluent, and then add 12 parts of nano-titanium dioxide, 25 parts of silver-coated copper powder, 10 parts of polyaniline / polypyrrole (mass ratio 2:1), 5 parts of silver-coated carbon fiber, 0.5 parts of titanate coupling agent, 2 parts of nano-silica dispersant, 1 part of defoaming agent BYK-022, and 0.5 parts of leveling agent BYK-358N, and stir and mix thoroughly to obtain component A.

[0055] Ethylenediamine is used as component B.

[0056] Component A and component B are mixed in a mass ratio of 100:25 and sprayed on the PET surface to obtain a broadband electromagnetic shielding coating.

[0057] Example 3

[0058] Nano-titanium dioxide with a particle size of 50 to 100 nm, silver-coated copper powder with a particle size of 10 to 15 μm, and silver-coated carbon fiber with a length of 100 to 500 μm are prepared for use;

[0059] Mix 45 parts of bisphenol A epoxy resin with 6 parts of diluent, then add 6 parts of nano-titanium dioxide, 12 parts of silver-coated copper powder, 4 parts of polythiophene, 1 part of silver-coated carbon fiber, 0.5 parts of titanate coupling agent, 1 part of nano-silicon dioxide dispersant, 1 part of defoaming agent BYK-022, 0.5 parts of leveling agent BYK-358N, and 0.5 parts of modified bentonite thixotropic agent, and stir and mix thoroughly to obtain component A.

[0060] Triethylenetetramine is used as component B.

[0061] Component A and component B are mixed in a mass ratio of 100:15 and sprayed on the PET surface to obtain a broadband electromagnetic shielding coating.

[0062] Example 4

[0063] Nano-titanium dioxide with a particle size of 50 to 80 nm, silver-coated copper powder with a particle size of 10 to 20 μm, and silver-coated carbon fiber with a length of 500 to 100 μm are prepared for use;

[0064] Mix 40 parts of bisphenol F epoxy resin with 5 parts of diluent, then add 10 parts of nano-titanium dioxide, 18 parts of silver-coated copper powder, 5 parts of polyaniline, 3 parts of silver-coated carbon fiber, 0.5 parts of titanate coupling agent, 1.5 parts of nano-silicon dioxide dispersant, 1 part of defoamer BYK-022, and 0.5 parts of leveling agent BYK-358N, and stir thoroughly to obtain component A.

[0065] Polyamide 650 is used as the B component.

[0066] Component A and component B are mixed in a mass ratio of 100:20 and sprayed on the PET surface to obtain a broadband electromagnetic shielding coating.

[0067] Example 5

[0068] Nano-titanium dioxide with a particle size of 10 to 60 nm, silver-coated copper powder with a particle size of 20 to 30 μm, and silver-coated carbon fiber with a length of 300 to 800 μm are prepared for use;

[0069] Mix 56 parts of bisphenol F epoxy resin with 8 parts of diluent, then add 14 parts of nano titanium dioxide, 30 parts of silver-coated copper powder, 3 parts of polyaniline, 2 parts of silver-coated carbon fiber, 0.5 parts of titanate coupling agent, 1 part of nano alumina dispersant, 0.5 parts of defoamer BYK-022, and 1 part of leveling agent BYK-358N, and stir thoroughly to obtain component A.

[0070] Polyamide 651 is used as the B component.

[0071] Component A and component B are mixed in a mass ratio of 100:20 and sprayed on the PET surface to obtain a broadband electromagnetic shielding coating.

[0072] Comparative Example 1

[0073] The only difference between this comparative example and Example 1 is that no nano titanium dioxide is added.

[0074] Comparative Example 2

[0075] The only difference between this comparative example and Example 1 is that no conductive polymer is added.

[0076] Experimental Example 1

[0077] The shielding effectiveness of the electromagnetic shielding coatings obtained in Examples 1 to 3 and Comparative Examples 1 to 2 was tested in accordance with GB / T 30142-2013. The test results are shown in Table 1.

[0078] Table 1 Shielding effectiveness test results

[0079]

[0080] Table 1 shows that the electromagnetic shielding coating prepared by the present invention has excellent shielding effectiveness and can achieve effective electromagnetic shielding over a wide frequency range. A comparison of Example 1 of the present invention and Comparative Example 1 shows that the addition of nano-titanium dioxide can effectively improve shielding effectiveness. A comparison with Comparative Example 2 shows that the conductive polymer plays a promoting role in the electromagnetic shielding coating, actually participating in the construction of the conductive network. Unlike traditional conductive networks formed solely by one-dimensional materials and small-sized particles, the present invention strengthens the connection between the components of the conductive network by adding a conductive polymer, thereby enhancing electronic conduction.

[0081] The coatings obtained in Examples 1 to 3 of the present invention have an operating frequency of 30 MHz to 10 GHz and a low surface density. The electromagnetic shielding coatings prepared by the present invention significantly enhance self-cleaning performance due to the synergistic effect of the photocatalytic activity and hydrophilicity of nano-titanium dioxide. Titanium dioxide generates electron-hole pairs under ultraviolet irradiation, forming highly active free radicals (such as hydroxyl radicals and superoxide radicals). These free radicals can decompose organic matter, such as oil stains and microorganisms, into water-soluble substances.

[0082] The various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referenced to each other.

[0083] The above description of the disclosed embodiments is intended to enable one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be readily apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not limited to the embodiments shown herein but is intended to conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A broadband electromagnetic shielding coating based on nano-titanium dioxide, characterized in that: It includes component A and component B; Wherein, component A includes the following components in parts by mass: 40-60 parts of waterborne epoxy resin, 5-15 parts of nano-titanium dioxide, 10-30 parts of silver-coated copper powder, 3-10 parts of conductive polymer, 1-5 parts of silver-coated carbon fiber, 0.5-1 part of coupling agent, 5-10 parts of diluent, and 0.1-5 parts of additives; Component B includes a curing agent.

2. The broadband electromagnetic shielding coating based on nano-titanium dioxide according to claim 1, characterized in that: The waterborne epoxy resin includes bisphenol A epoxy resin and / or bisphenol F epoxy resin.

3. The broadband electromagnetic shielding coating based on nano-titanium dioxide according to claim 2, characterized in that: The particle size of the nano titanium dioxide is 10 to 100 nm.

4. A broadband electromagnetic shielding coating based on nano-titanium dioxide according to any one of claims 1 to 3, characterized in that: The particle size of the silver-coated copper powder is 10 to 30 μm; the mass content of silver in the silver-coated copper powder is 18 to 22%.

5. The broadband electromagnetic shielding coating based on nano-titanium dioxide according to claim 4, characterized in that: The conductive polymer includes one or more of polyaniline, polypyrrole, polythiophene and polyethylenedioxythiophene.

6. The broadband electromagnetic shielding coating based on nano-titanium dioxide according to claim 5, characterized in that: The length of the silver-coated carbon fiber is 80 to 1000 μm.

7. A broadband electromagnetic shielding coating based on nano-titanium dioxide according to claim 5 or 6, characterized in that: The coupling agent includes an aminosilane coupling agent and / or a titanate coupling agent; The diluent includes water; The auxiliary agent includes one or more of a dispersant, a defoaming agent, a leveling agent and a thixotropic agent.

8. The method for preparing a broadband electromagnetic shielding coating based on nano-titanium dioxide according to any one of claims 1 to 7, characterized in that: The preparation method of component A of the broadband electromagnetic shielding coating based on nano-titanium dioxide comprises the following steps: Fully mixing waterborne epoxy resin, nano-titanium dioxide, silver-coated copper powder, conductive polymer, silver-coated carbon fiber, coupling agent, diluent, and additives to obtain component A; The B component includes a curing agent; When used, the mass ratio of component A to component B is 100:15-25.

9. Use of the broadband electromagnetic shielding coating based on nano-titanium dioxide according to any one of claims 1 to 6 in the preparation of electromagnetic shielding materials.

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