A polyurea coating material with integrated electromagnetic shielding and explosion-proof functions and a preparation method thereof

Abstract

The present invention belongs to the field of electromagnetic attack and explosion resistance, and specifically relates to a polyurea coating material and a preparation method thereof. The present invention provides a polyurea coating material with integrated electromagnetic shielding and explosion resistance functions, a novel high-strength and high-toughness polyurea elastomer is combined with an electromagnetic shielding filler, and a cage-type polysilsesquioxane is introduced to improve the interfacial adhesion. The polyurea coating material has both explosion resistance and electromagnetic shielding performance, and can protect against physical attacks and electromagnetic attacks at the same time, which is of great significance for engineering protection and has great application potential in the field of electromagnetic attack and explosion resistance.

Description

Technical Field

[0001] The invention belongs to the technical field of electromagnetic attack protection and explosion resistance, and specifically relates to a polyurea coating material and a preparation method thereof. Background Art

[0002] Polyurea is an elastomeric substance generated by the reaction of isocyanate and amino compounds. Compared with traditional coatings, it has the following advantages: good inertness, not affected by ambient temperature and humidity during construction; no volatile organic compounds, environmentally friendly; good material adhesion, can be sprayed on concrete, metal plates, wood and other substrates; no catalyst, can achieve rapid curing, spray without sagging, can be sprayed on various shapes, gel in five seconds, sixty seconds with walking strength; can be hot sprayed and poured, with high construction efficiency and adjustable thickness, beautiful coating can be formed in one time; has excellent mechanical properties, including tensile strength, fracture toughness, elongation at break and tear strength, and has the advantages of anti-slip, aging resistance, corrosion resistance, etc.; has excellent thermal stability and flame retardancy, can be used for a long time at 120°C, can withstand short-term thermal shock of 350°C, has low fire spread rate and can be self-extinguishing.

[0003] The explosive load has a short action time and will cause great damage to the engineering structure. Under the impact load, the splash of structural fragments will also cause secondary damage. The high-energy electromagnetic pulses generated by nuclear explosions and high-power electromagnetic weapons have seriously affected the security of battlefield cyberspace. It is urgent to develop materials with excellent electromagnetic protection performance. Electromagnetic shielding is the attenuation of electromagnetic waves caused by the absorption or reflection of conductive or magnetic materials during the propagation of electromagnetic waves. Its effect is often expressed by electromagnetic interference shielding effectiveness (EMI SE) in decibels (dB). The transmission line theory in the electromagnetic interference shielding mechanism believes that when electromagnetic waves are incident on shielding materials, three electromagnetic wave loss mechanisms will occur: reflection loss, absorption loss, and multiple reflection loss. The modern battlefield strikes are diversified, and fortifications and equipment have both explosion-proof and electromagnetic shielding needs, but there are few studies on materials that can integrate explosion-proof and electromagnetic shielding. In order to make polyurea materials have excellent electromagnetic shielding performance, a large amount of electromagnetic shielding fillers need to be added to the polyurea materials, but this will reduce the mechanical properties of the polyurea materials and cannot meet the explosion-proof requirements. Summary of the invention

[0004] In view of this, the object of the present invention is to provide a polyurea coating material and a preparation method thereof. The polyurea coating material provided by the present invention has excellent electromagnetic shielding effectiveness and explosion-proof function.

[0005] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0006] The present invention provides a polyurea coating material, comprising polyurea layers and electromagnetic shielding layers alternately stacked;

[0007] The polyurea layer is prepared from a mixture A and a mixture B; the mixture A comprises the following components in parts by weight: 100-500 parts of a diamine, 10-30 parts of aminopyridine and 10-100 parts of an ammonium salt cage-type polysilsesquioxane; based on the parts by weight of the diamine, the mixture B comprises the following components in parts by weight: 100-500 parts of a diisocyanate and 10-20 parts of a zinc salt;

[0008] The electromagnetic shielding layer is prepared from electromagnetic shielding slurry. Based on the weight of diamine, the electromagnetic shielding slurry comprises the following components in weight: 10-50 parts of electromagnetic shielding filler, 1-5 parts of hydroxy cage polysilsesquioxane and 100-500 parts of solvent.

[0009] Preferably, the diisocyanate includes aliphatic diisocyanate and aromatic diisocyanate.

[0010] Preferably, the mass fraction of the aromatic diisocyanate in the diisocyanate is 70 to 95%.

[0011] Preferably, the diamine includes a diamine with a number average molecular weight of 200 to 400 and a diamine with a number average molecular weight of 1000 to 5000.

[0012] Preferably, the mass fraction of the diamine with a number average molecular weight of 200 to 400 in the diamine is 10 to 30%.

[0013] Preferably, the electromagnetic shielding filler includes carbon material and / or metal material.

[0014] Preferably, the solvent includes one or more of water, ethanol, ethylene glycol, glycerol, isopropanol, acetone, tetrahydrofuran, toluene and N,N-dimethylformamide.

[0015] Preferably, the thickness of the polyurea layer is 0.2-20 mm.

[0016] Preferably, the amount of electromagnetic shielding slurry loaded on each polyurea layer is 50 to 5000 mg / m 2 .

[0017] The present invention also provides a method for preparing the polyurea coating material described in the above technical solution, comprising the following steps:

[0018] The mixture A and the mixture B are mixed and coated to obtain a polyurea layer;

[0019] The electromagnetic shielding slurry is coated on the surface of the polyurea layer to form an electromagnetic shielding layer, thereby obtaining the polyurea coating material.

[0020] The present invention provides a polyurea coating material, comprising polyurea layers and electromagnetic shielding layers alternately stacked;

[0021] The polyurea layer is prepared from a mixture A and a mixture B; the mixture A comprises the following components in parts by weight: 100-500 parts of a diamine, 10-30 parts of aminopyridine and 10-100 parts of an ammonium salt cage-type polysilsesquioxane; based on the parts by weight of the diamine, the mixture B comprises the following components in parts by weight: 100-500 parts of a diisocyanate and 10-20 parts of a zinc salt;

[0022] The electromagnetic shielding layer is prepared from electromagnetic shielding slurry. Based on the weight of diamine, the electromagnetic shielding slurry comprises the following components in weight: 10-50 parts of electromagnetic shielding filler, 1-5 parts of hydroxy cage polysilsesquioxane and 100-500 parts of solvent.

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] The polyurea coating material provided by the present invention combines an electromagnetic shielding layer with a polyurea layer, is an integrated polyurea coating of electromagnetic shielding and explosion-proof functions, has both explosion-proof performance and electromagnetic shielding performance, can simultaneously protect against physical attacks and electromagnetic attacks, and has excellent performance stability, is of great significance for engineering protection, and has great application potential in the field of electromagnetic attack and explosion-proof. The polyurea layer of the present invention is prepared from a mixture A and a mixture B, wherein the mixture A is compounded with diamine, aminopyridine and ammonium salt cage polysilsesquioxane to control the soft and hard segment ratio of the polyurea molecular chain, and the zinc ions of the zinc salt in the mixture B form coordination bonds with the nitrogen atoms and oxygen atoms on the polyurea molecular chain, and the synthesized polyurea has high strength and high toughness. At the same time, adding hydroxy cage polysilsesquioxane to the electromagnetic shielding layer can improve the dispersibility of the electromagnetic shielding slurry, and complement the ammonium salt cage polysilsesquioxane on the polyurea molecular chain, and can enhance the interface compatibility and interface adhesion between the polyurea layer and the electromagnetic shielding layer. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0026] Figure 1 This is a schematic diagram of the structure of the integrated polyurea coating material with electromagnetic shielding and explosion-proof functions obtained in Example 2. DETAILED DESCRIPTION

[0027] The present invention provides a polyurea coating material, comprising polyurea layers and electromagnetic shielding layers alternately stacked;

[0028] The polyurea layer is prepared from a mixture A and a mixture B; the mixture A comprises the following components in parts by weight: 100-500 parts of a diamine, 10-30 parts of aminopyridine and 10-100 parts of an ammonium salt cage-type polysilsesquioxane; based on the parts by weight of the diamine, the mixture B comprises the following components in parts by weight: 100-500 parts of a diisocyanate and 10-20 parts of a zinc salt;

[0029] The electromagnetic shielding layer is prepared from electromagnetic shielding slurry. Based on the weight of diamine, the electromagnetic shielding slurry comprises the following components in weight: 10-50 parts of electromagnetic shielding filler, 1-5 parts of hydroxy cage polysilsesquioxane and 100-500 parts of solvent.

[0030] In the present invention, unless otherwise specified, the materials and equipment used are commercially available products in the art.

[0031] In the present invention, the mixture A preferably comprises the following components in parts by weight: 100-200 parts of diamine, 12-15 parts of aminopyridine and 12-15 parts of ammonium salt cage-type polysilsesquioxane; more preferably comprises the following components in parts by weight: 100 parts of diamine, 15 parts of aminopyridine and 15 parts of ammonium salt cage-type polysilsesquioxane.

[0032] In the present invention, the diamine preferably includes diamines of different molecular weights, and the diamines of different molecular weights preferably include diamines with a number average molecular weight of 200-400 and diamines with a number average molecular weight of 1000-5000; the number average molecular weight of the diamine with a number average molecular weight of 200-400 is preferably 230, and the number average molecular weight of the diamine with a number average molecular weight of 1000-5000 is preferably 2000; the diamine provides amino groups.

[0033] In the present invention, the mass fraction of the diamine with a number average molecular weight of 200 to 400 in the diamine is preferably 10 to 30%, more preferably 15 to 20%. The diamine with a number average molecular weight less than 400 in the present invention can adjust the mechanical properties of the polyurea layer.

[0034] In the present invention, the diamine preferably includes one or more of 4,4'-diaminodiphenyl ether, diethyltoluenediamine, 1,3-propylene glycol bis(4-aminobenzoate), polyetheramine and 3,3'-dichloro-4,4'-diaminophenylmethane, and the polyetheramine preferably includes poly(propylene glycol) bis(2-aminopropyl ether).

[0035] In the present invention, the aminopyridine can form a metal coordination bond with the zinc salt to improve the strength and toughness of the polyurea layer.

[0036] In the present invention, the aminopyridine preferably includes one or more of 4,4'-diamino-2,2'-bipyridine, 2,6-diaminopyridine, 2,3-diaminopyridine and 3,4-diaminopyridine.

[0037] In the present invention, the structural formula of the ammonium salt cage-type polysilsesquioxane is preferably as shown in Formula I:

[0038]

[0039] In the present invention, the manufacturer and model of the ammonium salt cage-type polysilsesquioxane is preferably Hybrid PlasticsMS0860.

[0040] In the present invention, the ammonium salt cage-type polysilsesquioxane preferably includes tetramethylammonium cage-type polysilsesquioxane. The ammonium salt cage-type polysilsesquioxane can introduce rigid groups and ionic bonds to improve the mechanical properties of the polyurea layer.

[0041] In the present invention, based on the weight of the diamine, the mixture B preferably includes the following components in parts by weight: 125-200 parts of diisocyanate and 10-15 parts of zinc salt; more preferably includes the following components in parts by weight: 125 parts of diisocyanate and 10 parts of zinc salt.

[0042] In the present invention, the diisocyanate preferably includes aliphatic diisocyanate and aromatic diisocyanate, the mass fraction of aromatic diisocyanate in the diisocyanate is preferably 70-95%, more preferably 80-92%, and the diisocyanate provides isocyanate groups.

[0043] In the present invention, the aliphatic diisocyanate preferably includes one or more of isophorone diisocyanate, 4,4'-dicyclohexylmethane diisocyanate and hexamethylene diisocyanate; the aromatic diisocyanate preferably includes one or more of toluene diisocyanate, 4,4'-diphenylmethane diisocyanate and 1,5-naphthalene diisocyanate.

[0044] In the present invention, the zinc salt preferably includes one or more of ZnCl2, ZnSO4, Zn(NO3)2, Zn(ClO4)2 and Zn(BF4)2. The zinc salt forms a metal coordination bond with aminopyridine, and the negative ions in the zinc salt form ionic bonds with ammonium salt cage-type polysilsesquioxane, thereby improving the strength and toughness of the polyurea layer.

[0045] In the present invention, based on the weight percentage of the diamine, the electromagnetic shielding slurry preferably includes the following components in weight percentage: 10 to 20 parts of electromagnetic shielding filler, 1 to 2 parts of hydroxyl cage polysilsesquioxane and 200 to 500 parts of solvent, and more preferably includes the following components in weight percentage: 10 parts of electromagnetic shielding filler, 2 parts of hydroxyl cage polysilsesquioxane and 500 parts of solvent.

[0046] In the present invention, the electromagnetic shielding filler preferably includes carbon material and / or metal material, and the carbon material preferably includes one or more of graphene, reduced graphene oxide and carbon nanotubes; the metal material preferably includes one or more of metal grids, metal nanosheets, metal nanotubes, metal nanofibers and metal nanowires; when the metal material is preferably a mixture of metal nanowires and metal nanofibers, the mass ratio of the metal nanowires and metal nanofibers is preferably 1 to 10:1 to 10.

[0047] In the present invention, the structural formula of the hydroxy cage polysilsesquioxane is preferably as shown in Formula II, wherein x and y in Formula II are independently integers of 2 to 11; the preparation method of the hydroxy cage polysilsesquioxane is referred to Chinese patent application number 201610606148.9;

[0048]

[0049] The hydroxy cage-type polysilsesquioxane can increase the dispersibility and hydrophilicity of the electromagnetic shielding slurry, and simultaneously improve the interface bonding force between the polyurea layer and the electromagnetic shielding layer together with the ammonium salt polysilsesquioxane in the polyurea.

[0050] In the present invention, the solvent preferably includes one or more of water, ethanol, ethylene glycol, glycerol, isopropanol, acetone, tetrahydrofuran, toluene and N,N-dimethylformamide.

[0051] In the present invention, the polyurea layer and the electromagnetic shielding layer are alternately stacked, that is, the polyurea layer is separated by the electromagnetic shielding layer, and the electromagnetic shielding layer is separated by the polyurea layer; the total number of polyurea layers and electromagnetic shielding layers is preferably 2 to 100 layers, more preferably 3 to 20 layers, and even more preferably 5, 7 or 9 layers.

[0052] In the present invention, the thickness of the polyurea layer is preferably 0.2 to 20 mm, more preferably 9 to 15 mm, and even more preferably 13 mm.

[0053] In the present invention, the loading density of the electromagnetic shielding slurry of each polyurea layer is preferably 50 to 5000 mg / m 2 , more preferably 1200 to 2000 mg / m 2 .

[0054] The present invention also provides a method for preparing the polyurea coating material described in the above technical solution, comprising the following steps:

[0055] The mixture A and the mixture B are mixed and coated to obtain a polyurea layer;

[0056] The electromagnetic shielding slurry is coated on the surface of the polyurea layer to form an electromagnetic shielding layer, thereby obtaining the polyurea coating material.

[0057] In the present invention, the mixture A and the mixture B are mixed and coated to obtain a polyurea layer.

[0058] In the present invention, the polyurea layer is preferably disposed on the surface of a substrate, and the substrate preferably includes one or more of a cement board, a metal board, and a reinforced concrete board.

[0059] The present invention preferably performs surface treatment on the substrate before coating the polyurea layer. In a specific embodiment of the present invention, the surface treatment preferably includes the following steps: after polishing the substrate surface, dust and debris on the substrate surface are cleaned with an air gun, and then a layer of primer is applied; the polishing can increase the surface roughness of the substrate, and the primer can enhance the bonding force between the polyurea layer and the substrate; the primer preferably includes an amino alkyd primer and / or an epoxy sealing primer.

[0060] In the present invention, the mixture A and mixture B are mixed and coated preferably using spray polyurea elastomer technology, and the mixture A and mixture B form a polyurea layer with explosion-proof function during the spraying process; after the spraying, it is preferably also included in drying, and the drying temperature is preferably 25°C, and the time is preferably 2 to 20 minutes.

[0061] In the present invention, the molar ratio of isocyanate groups to amino groups in the mixture A and the mixture B is preferably 1.0 to 1.2.

[0062] After the polyurea layer is obtained, the present invention coats the electromagnetic shielding slurry on the surface of the polyurea layer to form an electromagnetic shielding layer, thereby obtaining the polyurea coating material.

[0063] In the present invention, the method of coating the electromagnetic shielding slurry preferably includes one or more of a doctor blade coating method, a casting method, a spray coating method and a spin coating method.

[0064] In the present invention, after coating the electromagnetic shielding slurry, it is preferred that drying and post-treatment are performed in sequence. The drying temperature is preferably 40 to 80°C, and the time is preferably 5 to 120s. The post-treatment method preferably includes one or more of ultraviolet light treatment, pulsed laser treatment, steam treatment, plasma treatment, heat treatment and solvent treatment. The solvent treatment preferably includes deionized water treatment. The post-treatment can reduce the contact resistance.

[0065] In the present invention, after the electromagnetic shielding layer is formed, it is preferably also included in curing, and the curing includes placing it in a room temperature anhydrous environment and placing it in a heated anhydrous environment in sequence, and the placing time in the room temperature anhydrous environment is preferably 1 to 12 hours; the temperature of the heated anhydrous environment is preferably 10 to 100°C, more preferably 80°C, and the placing time in the heated anhydrous environment is preferably 1 to 48 hours.

[0066] In order to further illustrate the present invention, the polyurea coating material and the preparation method thereof of the present invention are described in detail below in conjunction with the accompanying drawings and embodiments, but they should not be construed as limiting the protection scope of the present invention.

[0067] Example 1

[0068] In parts by weight, 100 parts of a polyetheramine composition (15 parts of a diamine with a number average molecular weight of 230, 85 parts of a diamine with a number average molecular weight of 2000), 15 parts of aminopyridine (4,4'-diamino-2,2'-bipyridine), and 15 parts of ammonium salt cage-type polysilsesquioxane are dispersed and stirred to obtain component A; 125 parts of a diisocyanate composition (10 parts of aliphatic diisocyanate: isophorone diisocyanate, 115 parts of aromatic diisocyanate: 1,5-naphthalene diisocyanate) and 10 parts of zinc salt (ZnCl2) are stirred evenly to obtain component B; component A and component B are used in the above-mentioned ratio to prepare a polyurea layer; 10 parts of electromagnetic shielding filler (a mixture of metal nanowires and metal nanofibers in a weight ratio of 10:1) and 2 parts of hydroxyl cage-type polysilsesquioxane are stirred and dispersed in 500 parts of a solvent to obtain an electromagnetic shielding slurry.

[0069] The reinforced concrete slab is treated by grinding the surface, using an air gun to clean the dust and debris on the surface, and applying a layer of primer; spraying a layer of polyurea on the reinforced concrete slab, and after the polyurea layer is dry, spray 1200mg / m 2 The electromagnetic shielding slurry with high load density is coated on the surface of the polyurea layer, and the electromagnetic shielding slurry is dried and post-processed; then a layer of polyurea is sprayed, and after the polyurea layer is dry, 1200mg / m 2 The electromagnetic shielding slurry with load density is dried and post-processed; and then a polyurea layer is sprayed. In this way, an electromagnetic shielding and explosion-resistant integrated polyurea coating material with a nine-layer laminated structure is prepared, which is placed in an anhydrous environment at room temperature for 12 hours and in an anhydrous environment at 80°C for 48 hours. In this embodiment, the thickness of the polyurea layer is 13 mm, and the post-processing is deionized water treatment.

[0070] The reinforced concrete slab sprayed with the polyurea coating of Example 1 was placed in a dug pit, 2 bricks were placed under the reinforced concrete slab, 200g of TNT explosives were placed 10cm above the center of the slab, and the explosives were detonated by electric detonators. The anti-explosion protection effect of the polyurea coating was evaluated by the sample morphology before and after the anti-explosion test. The back explosion surface achieved a zero-fragment protection effect, which can effectively resist the secondary damage that may be caused by the explosion fragments, and has a very high application value in the field of engineering protection.

[0071] Example 2

[0072] The difference between this embodiment and embodiment 1 is that an electromagnetic shielding and explosion-resistant integrated polyurea coating material having a seven-layer laminated structure is prepared by analogy. Figure 1 This is a schematic diagram of the structure of the integrated polyurea coating material with electromagnetic shielding and explosion-proof functions obtained in Example 2.

[0073] Example 3

[0074] The difference between this embodiment and embodiment 1 is that an electromagnetic shielding and explosion-resistant integrated polyurea coating material having a five-layer laminated structure is prepared by analogy.

[0075] The tensile strength of the polyurea layer synthesized in Example 1 is 108.2 MPa, the elongation at break is 1107.6%, and the fracture toughness is 616.2 MJ / m 3 The tear strength is 126.3N / mm (tensile strength is tested according to GB / T 1040-92 standard, and tear strength is tested according to ASTMD624 standard).

[0076] The highest electromagnetic interference shielding effectiveness results of the polyurea coating materials of Examples 1 to 3 in the frequency range of 2 to 18.0 GHz are shown in Table 1. After being placed in indoor conditions for one year, the electromagnetic shielding efficiency retention rate is 100%, indicating that the polyurea coating material of the present invention has excellent performance stability.

[0077] Table 1 Performance results of polyurea coating materials of Examples 1 to 3

[0078] Example 1 Example 2 Example 3 Highest electromagnetic shielding effectiveness 120.0dB 107.8dB 79.3dB Back explosion surface damage diameter 1cm 2cm 3cm Back blast surface fragmentation rate 0 0 0

[0079] Comparative Example 1

[0080] The difference between this comparative example and Example 1 is that no ammonium salt cage-type polysilsesquioxane is added. The tensile strength of the synthesized polyurea layer is 80.8 MPa, the elongation at break is 1747.2%, and the fracture toughness is 421.7 MJ / m 3 , the tear strength is 97.7N / mm.

[0081] Comparative Example 2

[0082] The difference between this comparative example and Example 1 is that no hydroxy cage-type polysilsesquioxane is added.

[0083] The interfacial bonding properties of the coatings of Example 1 and Comparative Example 2 were evaluated by an indirect loading double shear test. The maximum axial tensile stress at the time of failure of the sample without the addition of hydroxyl cage polysilsesquioxane was 62.1 MPa, and the maximum axial tensile stress at the time of failure of the sample with the addition of hydroxyl cage polysilsesquioxane was 68.6 MPa. It can be seen that the hydroxyl cage polysilsesquioxane improves the interfacial bonding force between the polyurea layer and the electromagnetic shielding layer.

[0084] Although the above-mentioned embodiments have made a detailed description of the present invention, they are only some embodiments of the present invention, rather than all embodiments. People can also obtain other embodiments based on the embodiments of the present invention without creative work, and these embodiments all fall within the scope of protection of the present invention.

Claims

1. A polyurea coating material, characterized in that: comprising alternately stacked polyurea layers and electromagnetic shielding layers; The polyurea layer is prepared from a mixture A and a mixture B; the mixture A comprises the following components in parts by weight: 100-500 parts of a diamine, 10-30 parts of aminopyridine and 10-100 parts of an ammonium salt cage-type polysilsesquioxane; based on the parts by weight of the diamine, the mixture B comprises the following components in parts by weight: 100-500 parts of a diisocyanate and 10-20 parts of a zinc salt; The diamines include diamines with a number average molecular weight of 200 to 400 and diamines with a number average molecular weight of 1000 to 5000; the mass fraction of the diamines with a number average molecular weight of 200 to 400 in the diamines is 10 to 30%; The raw material for preparing the electromagnetic shielding layer is electromagnetic shielding slurry. Based on the weight proportion of diamine, the electromagnetic shielding slurry includes the following components in weight proportions: 10 to 50 parts of electromagnetic shielding filler, 1 to 5 parts of hydroxyl cage polysilsesquioxane and 100 to 500 parts of solvent; the electromagnetic shielding filler includes metal material, the metal material includes metal nanofibers and metal nanowires, and the mass ratio of the metal nanowires to the metal nanofibers is 1 to 10:1 to 10.

2. The polyurea coating material according to claim 1, characterized in that: The diisocyanate includes aliphatic diisocyanate and aromatic diisocyanate.

3. The polyurea coating material according to claim 2, characterized in that: The mass fraction of the aromatic diisocyanate in the diisocyanate is 70-95%.

4. The polyurea coating material according to claim 1, characterized in that: The solvent includes one or more of water, ethanol, ethylene glycol, glycerol, isopropanol, acetone, tetrahydrofuran, toluene and N,N-dimethylformamide.

5. The polyurea coating material according to claim 1, characterized in that: The thickness of the polyurea layer is 0.2-20 mm.

6. The polyurea coating material according to claim 1, characterized in that: The loading density of the electromagnetic shielding slurry of each polyurea layer is 50-5000 mg / m 2 .

7. The method for preparing the polyurea coating material according to any one of claims 1 to 6, characterized in that: The following steps are involved: The mixture A and the mixture B are mixed and coated to obtain a polyurea layer; The electromagnetic shielding slurry is coated on the surface of the polyurea layer to form an electromagnetic shielding layer, thereby obtaining the polyurea coating material.

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