Noise reduction shielding film, preparation method and application thereof

Abstract

The present invention discloses a noise reduction shielding film, a preparation method and its application. The noise reduction shielding film comprises a base film, a silicon carbide coating and a printing layer from bottom to top. The silicon carbide in the base film and / or the silicon carbide coating is subjected to plasma strengthening treatment. The present invention treats the base film and / or the silicon carbide by plasma. After the plasma treatment, the impact of the high-energy particles of the plasma can introduce an additional bonding effect between the coating and the base film surface, so that the bonding between the base film and the silicon carbide coating is stronger, and the stability of the noise reduction shielding layer is improved. At the same time, the electromagnetic shielding and dispersibility of the silicon carbide after plasma treatment are significantly improved compared to ordinary silicon carbide. The noise reduction shielding film of the present invention has good performance and a wide range of applications. It can be used in electromagnetic shielding equipment and can also be applied to labels through a printing layer.

Description

Technical Field

[0001] The present invention relates to the technical field of electromagnetic shielding films, and in particular to a noise reduction shielding film, a preparation method and applications thereof. Background Art

[0002] Driven by scientific and technological advancements and driven by human needs, electronic devices are becoming smaller, lighter, and more reliable. This requires portable electronic devices to have higher power and faster speeds. However, when operating at high power and speed, electronic devices radiate a large amount of high-frequency electromagnetic waves, generating electromagnetic interference. These electromagnetic waves can not only hinder the effective operation of nearby devices, but more seriously, pollute the ecological environment and endanger the health of organisms.

[0003] Electromagnetic shielding is one of the effective means of suppressing electromagnetic interference. Attaching a film layer with electromagnetic shielding properties to the surface of electronic equipment helps suppress electromagnetic disturbances. In order to meet the demand for electromagnetic shielding, it is necessary to improve traditional shielding materials. Among traditional shielding materials, silicon carbide has very high chemical stability. At any reasonable temperature, there is almost no diffusion of impurities within the material. Some studies have been conducted on materials with better electromagnetic shielding prepared based on silicon carbide. For example, CN115928043A discloses a graphene / silicon carbide composite material, its preparation method, and its application in electromagnetic shielding equipment. The graphene / silicon carbide composite material is prepared using laser chemical vapor deposition equipment with at least one of hexamethyldisilane, methyltrichlorosilane, silicon chloride, methane, and propane and hydrogen. The material has good electromagnetic shielding performance. However, the preparation conditions are relatively harsh and the equipment is relatively sophisticated, which limits industrial production. CN116926785A discloses a method for preparing a flexible silicon carbide nanofiber membrane for electromagnetic wave absorption. The method uses an electrospinning method to control titanium acetylacetonate, yttrium acetylacetonate, and zirconium acetylacetonate as reinforcing agents to prepare a nanofiber membrane for electromagnetic wave absorption. This method can produce flexible shielding membranes for various scenarios, but the efficiency of electrospinning is low, and reinforcing agents are uncommon and account for a large proportion.

[0004] In view of the problems of complex steps and expensive equipment in the current preparation of silicon carbide shielding materials, corresponding solutions need to be provided. Summary of the Invention

[0005] In order to overcome the problems existing in the prior art, the present invention provides a noise reduction shielding film, which includes a base film, a silicon carbide coating and a printing layer from bottom to top, and the silicon carbide in the base film and / or the silicon carbide coating is subjected to plasma strengthening treatment.

[0006] Furthermore, the parameters of the plasma enhancement treatment include using a dielectric barrier discharge at a voltage peak of 10 to 20 kV for 1 to 10 minutes under a gas flow rate of 300 to 500 mL / min of oxygen and / or argon.

[0007] Plasma strengthening treatment uses the high energy activity of plasma to chemically react and physically deposit on the surface of the material, thereby changing the chemical properties and physical structure of the material surface to achieve the purpose of strengthening treatment. The specific steps of plasma strengthening treatment include three stages: gas discharge, plasma generation, and surface treatment. First, gas is injected into the reaction chamber of the plasma treatment machine, and the gas molecules are excited by a high-frequency electric field, causing them to ionize into plasma. Then, under the action of the high-frequency electric field, the active substances in the plasma are activated, and have the ability to chemically react and physically deposit on the surface of the material. Finally, the chemical reaction and physical effects of the plasma are used to clean, activate, coat, and other treatments on the material surface. Plasma strengthening treatment has many advantages, including reducing the processing temperature, accelerating the processing speed, improving the processing quality, enhancing the strengthening effect, and reducing the processing cost.

[0008] The inventive concept of the present invention is to use plasma to treat the base film and / or silicon carbide. After the plasma treatment, the impact of high-energy plasma particles can introduce additional bonding effects between the coating and the base film surface, making the bonding between the base film and the silicon carbide coating stronger, thereby improving the stability of the noise reduction shielding layer. At the same time, the electromagnetic shielding and dispersibility of the silicon carbide after plasma treatment are significantly improved compared to ordinary silicon carbide, so that better electromagnetic shielding performance can be achieved by adding a smaller concentration.

[0009] Furthermore, the silicon carbide coating is obtained by mixing silicon carbide or plasma-treated silicon carbide, polyvinyl pyrrolidone, and a solvent in a mass ratio of 2-5:0.05-0.1:40-60 to obtain a slurry, which is then coated on a base film and dried.

[0010] Furthermore, the particle size of the silicon carbide or plasma-treated silicon carbide is 0.05 to 2 μm.

[0011] Furthermore, the thickness of the silicon carbide coating is 0.2 to 0.5 mm;

[0012] The silicon carbide is also treated with silane;

[0013] The plasma strengthened silicon carbide is subjected to silane treatment before the plasma strengthened silicon carbide is subjected to plasma strengthened treatment.

[0014] Silane treatment is a common surface modification method for inorganic materials. In the present invention, strict conditions for silane treatment are not required. Specifically, the silanization process involves reacting a silane coupling agent, silicon carbide, and a solvent, followed by collecting the insoluble matter, washing, and drying. The type of silane coupling agent is not strictly limited and can be at least one of KH550, KH560, KH580, etc. The amount of silane coupling agent used is preferably 0.02 to 0.5 times the mass of the silicon carbide. The solvent can be at least one of water, ethanol, acetone, etc.

[0015] Furthermore, the molecular weight of the polyvinyl pyrrolidone is 8000-200000;

[0016] The solvent includes at least one of ethyl acetate, butyl acetate and isopropyl acetate.

[0017] Nylon (PA), also known as polyamide, is a generic term for thermoplastic resins containing repeating amide groups ("NHCO") in their molecular backbone. Nylon is non-toxic, lightweight, and possesses excellent mechanical strength, wear resistance, and good corrosion resistance.

[0018] Furthermore, the base film is made of nylon with a thickness of 0.05 to 0.3 mm.

[0019] Polyethylene terephthalate (PET) is produced by either transesterifying dimethyl terephthalate with ethylene glycol or esterifying terephthalic acid with ethylene glycol to form bis(hydroxyethyl) terephthalate, followed by a polycondensation reaction. PET boasts high transparency, good gloss, excellent mechanical properties, high and low temperature resistance, chemical resistance, and good thermal transfer properties.

[0020] Furthermore, the printing layer is polyethylene terephthalate with a thickness of 0.02 to 0.1 mm.

[0021] The present invention also provides a method for preparing a noise reduction shielding film, comprising:

[0022] Preparing silicon carbide slurry;

[0023] A silicon carbide slurry is coated on the base film and then dried to form a silicon carbide coating;

[0024] preparing a printed layer on the silicon carbide coating;

[0025] The silicon carbide in the base film and / or the silicon carbide coating is subjected to plasma strengthening treatment.

[0026] The present invention also provides application of the noise reduction shielding film in electromagnetic shielding equipment.

[0027] Compared with the prior art, the present invention has the following beneficial effects:

[0028] The present invention uses plasma to treat the base film and / or silicon carbide. The plasma treatment, through the impact of high-energy plasma particles, introduces additional bonding between the coating and the base film surface, strengthening the bond between the base film and the silicon carbide coating and improving the stability of the noise-reducing shielding layer. Furthermore, the plasma-treated silicon carbide exhibits significantly improved electromagnetic shielding and dispersibility compared to conventional silicon carbide. The noise-reducing shielding film of the present invention has excellent performance and a wide range of applications. It can be used in electromagnetic shielding equipment and can also be applied to labels via a printed layer. DETAILED DESCRIPTION

[0029] The endpoints of the ranges and any values ​​disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoints of each range, the endpoints of each range and individual point values, and the individual point values ​​can be combined with each other to form one or more numerical ranges, and these numerical ranges should be considered to be specifically disclosed in the present invention.

[0030] Some of the raw materials used in the examples of the present invention are described as follows:

[0031] PA film, model 006, thickness 0.1 mm, purchased from Shanghai Baixin New Material Technology Co., Ltd.;

[0032] Silicon carbide, black, average particle size 0.5 μm, customized by Lianyungang Jiabei Silicon Carbide Co., Ltd.

[0033] Polyvinylpyrrolidone, model K25, molecular weight 30,000, was purchased from Wuhan Lvjing Fenghua Biotechnology Co., Ltd.

[0034] PET film, model X30, black, 0.05 mm thick, purchased from Toray, Japan;

[0035] All other raw materials not mentioned are commonly used in the art. The above description is merely provided to illustrate the present invention and is not to be construed as a strict limitation of the present invention. Those skilled in the art can purchase or prepare the same or similar raw materials commercially. These details will not be further detailed in the examples.

[0036] The following will be combined with specific embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0037] Example 1

[0038] A method for preparing a noise reduction shielding film, comprising the following steps:

[0039] S1. 30 g of silicon carbide, 0.8 g of polyvinyl pyrrolidone, and 500 g of isopropyl acetate were stirred and mixed at 1000 rpm for 30 min to obtain a silicon carbide slurry;

[0040] S2. The silicon carbide slurry was loaded into a slot coater and evenly coated on the surface of the plasma enhanced PA film through slot coating. The film was fully dried in a 4-section oven at a temperature of 150°C to obtain a silicon carbide coating with a thickness of 0.2 mm.

[0041] S3. Laminating a black PET film on the surface of the silicon carbide coating through a laminating machine to obtain a noise reduction and shielding film.

[0042] Among them, the preparation method of plasma-enhanced PA film is to place the PA film in a contact plasma discharge instrument, use dielectric barrier discharge in a gas atmosphere of oxygen and argon with a volume ratio of 1:2 at 350 mL / min, and treat it for 5 minutes at a voltage peak of 20 kV to obtain a plasma-enhanced PA film.

[0043] Example 2

[0044] A method for preparing a noise reduction shielding film, comprising the following steps:

[0045] S1, 30g of silane-treated silicon carbide, 0.8g of polyvinyl pyrrolidone, and 500g of isopropyl acetate were stirred and mixed at 1000rpm for 30min to obtain silicon carbide slurry;

[0046] S2. The silicon carbide slurry was loaded into a slot coater and evenly coated on the surface of the plasma enhanced PA film through slot coating. The film was fully dried in a 4-section oven at a temperature of 150°C to obtain a silicon carbide coating with a thickness of 0.2 mm.

[0047] S3. Laminating a black PET film on the surface of the silicon carbide coating through a laminating machine to obtain a noise reduction and shielding film.

[0048] The preparation method of the plasma enhanced PA film is the same as that in Example 1.

[0049] The preparation method of silane-treated silicon carbide is as follows: 20g of silicon carbide, 8g of KH580, and 100g of water are stirred at 400rpm for 2.5h, and then the insoluble matter is collected by filtration, washed three times with water and anhydrous ethanol respectively, and then placed in a constant temperature oven at 120°C for 8h to obtain silane-treated silicon carbide.

[0050] Example 3

[0051] A method for preparing a noise reduction shielding film, comprising the following steps:

[0052] S1. 30 g of modified silicon carbide, 0.8 g of polyvinyl pyrrolidone, and 500 g of isopropyl acetate were stirred and mixed at 1000 rpm for 30 min to obtain a silicon carbide slurry;

[0053] S2. The silicon carbide slurry was loaded into a slot coater and evenly coated on the surface of the plasma enhanced PA film through slot coating. The film was fully dried in a 4-section oven at a temperature of 150°C to obtain a silicon carbide coating with a thickness of 0.2 mm.

[0054] S3. Laminating a black PET film on the surface of the silicon carbide coating through a laminating machine to obtain a noise reduction and shielding film.

[0055] The preparation method of the plasma enhanced PA film is the same as that in Example 1.

[0056] The preparation method of modified silicon carbide is as follows: placing silicon carbide in a contact plasma discharge instrument, using dielectric barrier discharge in a gas atmosphere of oxygen and argon with a volume ratio of 1:2 at 350 mL / min, and treating it at a voltage peak of 25 kV for 5 minutes to obtain modified silicon carbide.

[0057] Example 4

[0058] A method for preparing a noise reduction shielding film, comprising the following steps:

[0059] S1. 30 g of modified silicon carbide, 0.8 g of polyvinyl pyrrolidone, and 500 g of isopropyl acetate were stirred and mixed at 1000 rpm for 30 min to obtain a silicon carbide slurry;

[0060] S2. The silicon carbide slurry was loaded into a slot coater and evenly coated on the surface of the plasma enhanced PA film through slot coating. The film was fully dried in a 4-section oven at a temperature of 150°C to obtain a silicon carbide coating with a thickness of 0.2 mm.

[0061] S3. Laminating a black PET film on the surface of the silicon carbide coating through a laminating machine to obtain a noise reduction and shielding film.

[0062] The preparation method of modified silicon carbide is as follows: placing silane-treated silicon carbide in a contact plasma discharge instrument, using dielectric barrier discharge in a gas atmosphere of oxygen and argon with a volume ratio of 1:2 at 350 mL / min, and treating it at a voltage peak of 25 kV for 5 minutes to obtain modified silicon carbide.

[0063] The preparation method of the plasma-enhanced PA film is the same as that of Example 1; the preparation method of the silane-treated silicon carbide is the same as that of Example 2.

[0064] Comparative Example 1

[0065] A method for preparing a noise reduction shielding film, comprising the following steps:

[0066] S1. 30 g of silicon carbide, 0.8 g of polyvinyl pyrrolidone, and 500 g of isopropyl acetate were stirred and mixed at 1000 rpm for 30 min to obtain a silicon carbide slurry;

[0067] S2. The silicon carbide slurry was loaded into a slot coater and evenly brushed on the surface of the PA film through slot coating. The film was fully dried in a 4-section oven at a temperature of 150°C to obtain a silicon carbide coating with a thickness of 0.2 mm.

[0068] S3. Laminating a black PET film on the surface of the silicon carbide coating through a laminating machine to obtain a noise reduction and shielding film.

[0069] Comparative Example 2

[0070] A method for preparing a noise reduction shielding film, comprising the following steps:

[0071] S1, 30g of silane-treated silicon carbide, 0.8g of polyvinyl pyrrolidone, and 500g of isopropyl acetate were stirred and mixed at 1000rpm for 30min to obtain silicon carbide slurry;

[0072] S2. The silicon carbide slurry was loaded into a slot coater and evenly brushed on the surface of the PA film through slot coating. The film was fully dried in a 4-section oven at a temperature of 150°C to obtain a silicon carbide coating with a thickness of 0.2 mm.

[0073] S3. Laminating a black PET film on the surface of the silicon carbide coating through a laminating machine to obtain a noise reduction and shielding film.

[0074] The preparation method of silane-treated silicon carbide is the same as that in Example 2.

[0075] Comparative Example 3

[0076] A method for preparing a noise reduction shielding film, comprising the following steps:

[0077] S1. 50 g of silicon carbide, 0.8 g of polyvinyl pyrrolidone, and 500 g of isopropyl acetate were stirred and mixed at 1000 rpm for 30 min to obtain a silicon carbide slurry;

[0078] S2. The silicon carbide slurry was loaded into a slot coater and evenly brushed on the surface of the PA film through slot coating. The film was fully dried in a 4-section oven at a temperature of 150°C to obtain a silicon carbide coating with a thickness of 0.2 mm.

[0079] S3. Laminating a black PET film on the surface of the silicon carbide coating through a laminating machine to obtain a noise reduction and shielding film.

[0080] Test Case

[0081] Referring to GB / T 1720-2020 "Paint Film Circle Test," the adhesion of the PA base film and silicon carbide coating of the noise reduction and shielding films (not coated with PET film) of the Examples and Comparative Examples was tested using a paint film circle tester. The results are shown in Table 1. The adhesion level is divided into seven grades, represented by numbers 1 to 7, with smaller numbers indicating stronger adhesion.

[0082] Table 1 Coating adhesion results

[0083]

[0084]

[0085] From the test results in Table 1, it can be seen that Comparative Example 3, which has a higher silicon carbide content, has the worst adhesion. The silicon carbide coating directly constructed with silicon carbide and polyvinyl pyrrolidone has poor adhesion to the PA film. At the same time, treating the silicon carbide with silane cannot effectively enhance the adhesion between the silicon carbide and the PA film. The adhesion of the PA film and silicon carbide coating of the embodiment is significantly stronger than that of the comparative example. This is because the PA film and / or silicon carbide material are plasma-enhanced. The impact of the high-energy plasma particles can introduce additional bonding between the coating and the base film surface, making the base film and the silicon carbide coating more bonded. At the same time, the dispersion of silicon carbide in the slurry is better, which suppresses the unevenness of the coating. Compared with Examples 1 to 3, Example 4 has a higher adhesion level, which shows that only by plasma-treating both the PA film and the silane-treated silicon carbide can the adhesion between the base film and the silicon carbide coating be further improved.

[0086] The X-band is a type of electromagnetic wave with a shorter wavelength and a higher frequency. It is between microwaves and infrared rays, with a frequency range of about 8GHz to 12GHz and a wavelength range of about 25mm to 37.5mm. The shielding efficiency values ​​of the shielding materials used in the silicon carbide coatings in the embodiments and comparative examples were tested using a vector network analyzer. The specific sample size was 22.86mm×10.06mm×2mm, and the shielding material was mixed with molten paraffin and then placed in a mold for solidification. The results of the shielding efficiency values ​​are shown in Table 2.

[0087] Table 2 Reflection loss results

[0088]

[0089]

[0090] From the test results in Table 2, it can be seen that the use of silane to treat silicon carbide does not significantly improve the X-band electromagnetic wave shielding performance, while the shielding performance of silicon carbide treated with plasma is significantly enhanced. Silanization treatment and plasma treatment have a good promoting effect, which makes plasma-modified silane-treated silicon carbide have the strongest X-band electromagnetic wave shielding performance.

[0091] Finally, it should be noted that the above is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art can still modify the technical solutions described in the aforementioned embodiments or make equivalent substitutions for some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A noise reduction shielding film, comprising, from bottom to top, a base film, a silicon carbide coating, and a printed layer, characterized in that: The silicon carbide in the base film and / or the silicon carbide coating is subjected to plasma strengthening treatment; The silicon carbide coating is obtained by mixing silicon carbide or plasma-strengthened silicon carbide, polyvinyl pyrrolidone, and a solvent in a mass ratio of 2-5:0.05-0.1:40-60 to obtain a slurry, which is then applied to a base film and dried. The particle size of the silicon carbide or plasma-strengthened silicon carbide is 0.05 to 2 μm; The silicon carbide is also treated with silane; The plasma strengthened silicon carbide is subjected to silane treatment before the plasma strengthened silicon carbide is subjected to plasma strengthened treatment.

2. The noise reduction shielding film according to claim 1, characterized in that The parameters of the plasma enhancement treatment include using oxygen and / or argon with a gas flow rate of 300-500 mL / min, using dielectric barrier discharge, and treating at a voltage peak of 15-25 kV for 1-10 minutes.

3. The noise reduction shielding film according to claim 1, characterized in that The thickness of the silicon carbide coating is 0.2-0.5 mm.

4. The noise reduction shielding film according to claim 1, characterized in that The molecular weight of the polyvinyl pyrrolidone is 8000-200000; The solvent includes at least one of ethyl acetate, butyl acetate and isopropyl acetate.

5. The noise reduction shielding film according to claim 1, characterized in that The base film is made of nylon with a thickness of 0.05 to 0.3 mm.

6. The noise reduction shielding film according to claim 1, characterized in that The printing layer is polyethylene terephthalate with a thickness of 0.02-0.1 mm.

7. A method for preparing a noise reduction shielding film, characterized in that: include, Preparing silicon carbide slurry; A silicon carbide slurry is coated on the base film and then dried to form a silicon carbide coating; preparing a printed layer on the silicon carbide coating; wherein the silicon carbide in the base film and / or the silicon carbide coating is subjected to plasma strengthening treatment; The silicon carbide coating is obtained by mixing silicon carbide or plasma-strengthened silicon carbide, polyvinyl pyrrolidone, and a solvent in a mass ratio of 2-5:0.05-0.1:40-60 to obtain a slurry, which is then applied to a base film and dried. The particle size of the silicon carbide or plasma-strengthened silicon carbide is 0.05 to 2 μm; The silicon carbide is also treated with silane; The plasma strengthened silicon carbide is subjected to silane treatment before the plasma strengthened silicon carbide is subjected to plasma strengthened treatment.

8. Use of the noise reduction shielding film according to any one of claims 1 to 6 in electromagnetic shielding equipment.

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