Electromagnetic shielding film and preparation method thereof

Abstract

The invention discloses an electromagnetic shielding film and a preparation method thereof.The electromagnetic shielding film is configured to be attached to a target object to shield electromagnetic radiation generated when the target object works, and the electromagnetic shielding film comprises a first base layer, an insulating layer, a shielding layer, a conductive adhesive layer and a second base layer which are sequentially arranged; the conductive adhesive layer is configured to enhance the adhesion between the shielding layer and a target object, the conductive adhesive layer and the shielding layer are configured to shield electromagnetic radiation generated by the target object during working, the shielding layer comprises an alloy made of a first metal with high conductivity and a second metal with high adhesive force, the first metal is different from the second metal, and the second metal is different from the first metal. And the shielding layer is manufactured by adopting an induction evaporation coating process. According to the electromagnetic shielding film and the preparation method thereof, the coating thickness and the shielding performance of the shielding layer can be controlled, and the manufacturing cost can be saved.

Description

Technical Field

[0001] The present invention relates to the technical field of electrical equipment housings or parts, and in particular to an electromagnetic shielding film and a preparation method thereof. Background Art

[0002] Electromagnetic shielding film is a new type of material that has the characteristics of preventing electromagnetic wave penetration and resisting electromagnetic radiation. It can reduce the impact of electromagnetic radiation generated by electrical and electronic equipment on the human body and is widely used in fields such as medical, military and building materials. Electromagnetic shielding film plays a shielding effect by reflecting, absorbing or attenuating electromagnetic waves to protect the human body and equipment from electromagnetic radiation. With the development of science and technology, the application range of electromagnetic shielding film will be wider, bringing more benefits to human life and health. For example, in the medical industry, electromagnetic shielding film can be used to protect medical equipment from external electromagnetic interference and ensure the normal operation of medical equipment. In the military field, electromagnetic shielding film can be used to protect military equipment from enemy interference and ensure the security of communications and intelligence. In addition, electromagnetic shielding film can also be used in the production of building materials. By adding electromagnetic shielding film to building materials, electromagnetic radiation inside the building can be effectively reduced and the quality of living and working environment can be improved. This is very important for those who work in the office for a long time.

[0003] The manufacturing process of the shielding layer in the existing electromagnetic shielding film is usually magnetron sputtering coating process, water plating (or electroplating) process, electron beam evaporation coating process or a combination thereof, but the aforementioned coating processes all have problems and disadvantages to varying degrees. For example, the water plating process will produce electroplating wastewater containing heavy metal ions and various acid mist waste gases, which are very likely to harm the environment; the magnetron sputtering coating process sputters out a small amount of molecules or atoms that volatilize, which will cause the thickness of the deposited film to be too thin; and the related equipment of the electron beam evaporation coating process is too expensive.

[0004] In addition, there are methods in the prior art that use the magnetron sputtering coating process and the water plating process to increase the coating thickness. For example, the magnetron sputtering coating process takes advantage of its strong adhesion to first coat a metal layer on the surface of the object to be plated, and then uses the water plating process to coat another metal layer on the surface of the aforementioned metal layer, thereby increasing the coating thickness. This solves the problem of too thin coating in the magnetron sputtering coating process. However, the above method of combining the two processes does not solve the problem that the water plating process is prone to pollute the environment; in addition, combining the two processes will also increase the manufacturing cost. Summary of the invention

[0005] The present invention aims to solve the above-mentioned problems and to provide an electromagnetic shielding film and a preparation method thereof which can control the coating thickness and shielding performance of the shielding layer and can save manufacturing costs.

[0006] To achieve the above-mentioned objectives, the first aspect of the present invention provides an electromagnetic shielding film, which is configured to be attached to a target object to shield the electromagnetic radiation generated by the target object when it is working, and includes a first base layer, an insulating layer, a shielding layer, a conductive adhesive layer and a second base layer arranged in sequence, the conductive adhesive layer is configured to enhance the adhesion with the shielding layer and the target object, the conductive adhesive layer and the shielding layer are configured to shield the electromagnetic radiation generated by the target object when it is working, wherein the shielding layer includes an alloy made of a first metal with strong conductivity and a second metal with strong adhesion, and the first metal is different from the second metal, and the shielding layer is made of an induction evaporation coating process.

[0007] In the present invention, the material for preparing the shielding layer is selected from an alloy made of a first metal with strong conductivity and a second metal with strong adhesion, and the physical and chemical properties of the shielding layer can be improved by proportioning the contents of multiple metals in the alloy, for example, the adhesion and electromagnetic shielding performance of the shielding layer can be improved, and the shielding layer can be made less susceptible to oxidation, etc.; in addition, the present invention adopts an induction evaporation coating process to prepare the shielding layer, which can easily control the film thickness of the shielding layer and reduce the manufacturing cost compared to the prior art method of combining a magnetron sputtering coating process with a water plating process.

[0008] In the electromagnetic shielding film involved in the first aspect of the present invention, optionally, the insulating layer is made of a mixture of epoxy resin, curing agent and carbon black.

[0009] In the electromagnetic shielding film involved in the first aspect of the present invention, optionally, the first metal is selected from one of gold, silver, copper, iron, aluminum, nickel, and titanium, and the second metal is selected from one of gold, silver, copper, aluminum, nickel, titanium, and chromium.

[0010] In the electromagnetic shielding film involved in the first aspect of the present invention, optionally, the content of the first metal in the alloy is 10%-90%, and the content of the second metal is 90%-10%.

[0011] In the electromagnetic shielding film involved in the first aspect of the present invention, optionally, the thickness of the insulating layer is 5 micrometers to 15 micrometers.

[0012] In the electromagnetic shielding film involved in the first aspect of the present invention, optionally, the thickness of the shielding layer is 0.1 micrometer to 2 micrometers.

[0013] In the electromagnetic shielding film involved in the first aspect of the present invention, optionally, the thickness of the conductive adhesive layer is 1 micrometer to 15 micrometers.

[0014] In the electromagnetic shielding film involved in the first aspect of the present invention, optionally, the conductive adhesive layer is made by coating a conductive adhesive on the shielding layer.

[0015] In the electromagnetic shielding film involved in the first aspect of the present invention, optionally, the conductive adhesive is made by mixing a curing agent, an epoxy resin and conductive particles.

[0016] In the electromagnetic shielding film involved in the first aspect of the present invention, optionally, it also includes a first base layer, and the first base layer is arranged on a side of the insulating layer away from the shielding layer.

[0017] In the electromagnetic shielding film involved in the first aspect of the present invention, optionally, the first base layer is removed when the electromagnetic shielding film is used.

[0018] In the electromagnetic shielding film involved in the first aspect of the present invention, optionally, the thickness of the first base layer is 10 micrometers to 100 micrometers.

[0019] In the electromagnetic shielding film involved in the first aspect of the present invention, optionally, a release agent is coated between the first base layer and the insulating layer.

[0020] In the electromagnetic shielding film involved in the first aspect of the present invention, optionally, it also includes a second base layer, and the second base layer is arranged on a side of the conductive adhesive layer away from the shielding layer.

[0021] In the electromagnetic shielding film involved in the first aspect of the present invention, optionally, the second base layer is removed when the electromagnetic shielding film is used, and after the second base layer is removed, at least a portion of the electromagnetic shielding film is adhered to a target object by utilizing the adhesion of the conductive adhesive layer.

[0022] In the electromagnetic shielding film involved in the first aspect of the present invention, optionally, a release agent is coated between the second base layer and the conductive adhesive layer.

[0023] In the electromagnetic shielding film involved in the first aspect of the present invention, optionally, the thickness of the second base layer is 10 micrometers to 100 micrometers.

[0024] A second aspect of the present invention provides a method for preparing an electromagnetic shielding film, the method comprising: preparing an insulating layer; depositing alloy vapor on one side of the insulating layer by an induction evaporation coating process to form a shielding layer on one side of the insulating layer, wherein the shielding layer comprises an alloy made of a first metal with strong conductivity and a second metal with strong adhesion, and the first metal is different from the second metal; coating a conductive adhesive on a side of the shielding layer away from the insulating layer to form a conductive adhesive layer on one side of the shielding layer.

[0025] In the method for preparing the electromagnetic shielding film involved in the second aspect of the present invention, optionally, the method further includes: preparing a first base layer; and coating an insulating glue on one side of the first base layer to form the insulating layer on the first base layer.

[0026] In the method for preparing the electromagnetic shielding film involved in the second aspect of the present invention, optionally, the method further comprises: preparing a second base layer, and bonding the side of the conductive adhesive layer away from the shielding layer to the second base layer.

[0027] In the preparation method of the electromagnetic shielding film involved in the second aspect of the present invention, optionally, the preparation steps of the conductive adhesive layer include: preparing epoxy resin, curing agent and conductive particles, and stirring the epoxy resin, the curing agent and the conductive particles to form a viscous, slurry-like conductive adhesive; applying the conductive adhesive on the surface of the shielding layer to form the conductive adhesive layer on the surface of the shielding layer, and drying and curing at room temperature.

[0028] In the method for preparing an electromagnetic shielding film involved in the second aspect of the present invention, optionally, the weight ratio of the epoxy resin, the curing agent and the carbon black is 100:5:1.

[0029] According to the present invention, an electromagnetic shielding film and a method for preparing the same can be provided, which can control the coating thickness and shielding performance of the shielding layer and save manufacturing costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] 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 or the description of the prior art will be briefly introduced below. Obviously, the drawings in the description are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0031] Figure 1 This is a structural diagram of the electromagnetic shielding film of the present invention attached to a target object.

[0032] Figure 2 This is a structural diagram of Example 1 of the electromagnetic shielding film of the present invention.

[0033] Figure 3 It is a structural diagram of Example 2 of the electromagnetic shielding film of the present invention.

[0034] Figure 4 This is a flow chart of Example 1 of the method for producing an electromagnetic shielding film of the present invention.

[0035] Figure 5 This is a flow chart of Example 2 of the method for producing an electromagnetic shielding film of the present invention. DETAILED DESCRIPTION

[0036] In order to make the purpose, technical solution and advantages of the invention clearer, the technical solution in the embodiment of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiment of the present invention. Obviously, the described embodiment is a part of the embodiment of the 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 work are within the scope of protection of the present invention.

[0037] Figure 1 It is a structural diagram of the electromagnetic shielding film of the present invention attached to the target 2.

[0038] Reference Figure 1 The present invention provides an electromagnetic shielding film 1. The electromagnetic shielding film 1 is usually used by attaching at least a portion of the electromagnetic shielding film 1 to a target object 2 to shield the electromagnetic radiation (such as electromagnetic waves, microwave rays, radiation, etc.) generated by the target object 2 during operation, thereby preventing the electromagnetic radiation generated by the target object 2 from affecting surrounding electronic devices. The target object 2 may be, for example, a mobile communication product (such as a mobile phone), a notebook or tablet computer, a smart wearable device, a drone, an electronic product (such as a digital camera), a medical instrument, an aerospace and defense electronic device, and the like.

[0039] Reference Figure 1 In some embodiments, the electromagnetic shielding film 1 may include an insulating layer 20. The insulating layer 20 may be configured to prevent the electronic circuit of the target object 2 from being turned on and thus affecting the normal operation of the target object 2. For example, the target object may not be turned on or short-circuited due to direct contact with the conductive adhesive layer 40 and the shielding layer 30.

[0040] In some embodiments, the insulating layer 20 may include epoxy resin, curing agent and carbon black. In some embodiments, the insulating layer 20 may be made by mixing epoxy resin, curing agent and carbon black.

[0041] In some embodiments, the thickness of the insulating layer 20 may be 5 micrometers to 15 micrometers. Preferably, the thickness of the insulating layer 20 may be 7 micrometers or 8 micrometers. Thus, the overall thickness of the electromagnetic shielding film can be maintained at a reasonable thickness.

[0042] In some embodiments, the components of the curing agent may include aliphatic amines. For example, ethylenetriamine, diethylenetriamine, triethylenetetramine, etc. Aliphatic amine curing agents have high reactivity, can be quickly cured at room temperature or low temperature, are insensitive to humidity, have certain color stability and good chemical resistance. In some embodiments, the components of the curing agent may include aromatic amines. For example, m-phenylenediamine, diaminodiphenylmethane, etc. Aromatic amine curing agents have good heat resistance and corrosion resistance. In some embodiments, the components of the curing agent may include amide amines. Amidoamine curing agents have low viscosity, good bonding properties, and also have good curing properties under humid conditions.

[0043] In some embodiments, the electromagnetic shielding film may include a shielding layer 30. The shielding layer 30 may be configured to shield electromagnetic radiation generated by the target object 2 during operation. The shielding layer 30 may be disposed on one side of the insulating layer 20.

[0044] In some embodiments, the shielding layer 30 may be a single layer or multiple layers. For example, the multiple layers may be 2 layers, 3 layers, 4 layers, 5 layers, 6 layers, 7 layers, 8 layers, 9 layers, etc. The material of each layer in the multiple layers may be the same or different. When the material of each layer is different, the excellent performance of the material of each layer can be fully utilized to enhance the electromagnetic shielding effect.

[0045] In some embodiments, the shielding layer 30 may be a copper layer. In other words, the shielding layer 30 may be composed of only a copper layer.

[0046] The electromagnetic shielding principle of the copper layer is as follows: copper is a good electrical conductor, and its electromagnetic shielding is mainly achieved by reflecting and absorbing electromagnetic waves. When electromagnetic waves encounter the surface of the copper layer, due to the high electrical conductivity of the copper layer, the electromagnetic waves will form currents on the surface of the copper layer. These currents generate reverse electromagnetic fields, thereby offsetting the incident electromagnetic waves. This is the reflection effect of the copper layer on electromagnetic waves. At the same time, the electrons inside the copper layer will vibrate under the action of electromagnetic waves, converting the energy of the electromagnetic waves into heat energy. This is the absorption effect of the copper layer on electromagnetic waves. The shielding effect of the copper layer is related to its thickness, surface treatment and the frequency of the electromagnetic waves. For example, the thicker the copper layer, the better the shielding effect.

[0047] In some embodiments, the thickness of the copper layer can be 0.5 microns to 2 microns. In this case, since the shielding effect of the copper layer is related to the thickness of the copper layer, by appropriately increasing the thickness of the copper layer, the shielding effect of the copper layer on the electromagnetic waves generated by the target 2 can be improved. Preferably, the thickness of the copper layer can be 1 micron. Thus, by designing the thickness of the copper layer to be 1 micron, the overall thickness of the electromagnetic shielding film 1 can be kept within a reasonable range.

[0048] In some embodiments, the shielding layer 30 may be a nickel layer. In other words, the shielding layer 30 may be composed of only a nickel layer.

[0049] The electromagnetic shielding principle of nickel layer is as follows: the electromagnetic shielding mechanism of nickel is similar to that of copper, which is mainly achieved by reflecting and absorbing electromagnetic waves. The nickel layer has good chemical stability, strong absorption and scattering ability of electromagnetic waves, and good electromagnetic shielding effect; in addition, the anti-oxidation ability of the nickel layer is stronger than that of the copper layer, and the price is moderate. The shielding effectiveness of the nickel layer can be improved by changing the conductivity (magnetic conductivity) of the nickel layer, especially when the frequency of the electromagnetic wave is low, the magnetic conductivity of the nickel layer is the decisive factor affecting its shielding performance.

[0050] In some embodiments, the thickness of the nickel layer can be 0.1 micron to 2 microns. In this case, since the shielding effect of the nickel layer is related to the thickness of the nickel layer, by appropriately increasing the thickness of the nickel layer, the shielding effect of the nickel layer on the electromagnetic waves generated by the target 2 can be improved. Preferably, the thickness of the nickel layer can be 0.5 microns. Thus, by designing the thickness of the nickel layer to be 0.5 microns, the overall thickness of the electromagnetic shielding film 1 can be kept within a reasonable range.

[0051] In some embodiments, the shielding layer 30 may include a nickel layer and a copper layer. The nickel layer and the copper layer may be stacked in sequence or arranged adjacently. In other words, the shielding layer 30 may be provided with both a nickel layer 31 and a copper layer 32. In this case, the electromagnetic shielding film 1 can integrate the excellent properties and electromagnetic shielding capabilities of the nickel layer and the copper layer, and can improve the electromagnetic shielding effect or electromagnetic shielding range of the electromagnetic shielding film 1 while improving the cost advantage (for example, it can be reflected by the price advantage of the nickel layer) and durability (for example, it can be reflected by the anti-oxidation ability of the nickel layer), etc. of the electromagnetic shielding film 1.

[0052] In some embodiments, a nickel layer may be first plated on the surface of the insulating layer 20 to increase adhesion, and then a copper layer may be plated on the nickel layer, thereby solving the problem of poor adhesion to the insulating layer 20 caused by direct copper plating.

[0053] In some embodiments, the nickel layer and / or copper layer may be in the form of a coating, a film, a conductive cloth, a conductive foam, etc. For example, the conductive cloth is made by chemically depositing or physically transferring metal nickel onto polyester or the like, and then plating a highly conductive copper layer on the nickel. The combination of the nickel layer and the copper layer can provide excellent conductivity and electromagnetic shielding effect, and the electromagnetic shielding range can be 100KHz to 3GHz.

[0054] In some embodiments, the shielding layer 30 may be a silver layer. In other words, the shielding layer may be composed of only a silver layer.

[0055] The electromagnetic shielding principle of the silver layer is: silver is an excellent electrical conductor, and its electromagnetic shielding is mainly achieved through reflection. When the electromagnetic wave encounters the surface of the silver layer, due to the high electrical conductivity of the silver layer, the electromagnetic wave will form a current on the surface of the silver layer. These currents generate a reverse electromagnetic field, thereby offsetting the incident electromagnetic wave. This is the reflection effect of the silver layer on the electromagnetic wave. In addition, part of the electromagnetic wave energy will also be absorbed by the silver layer. The electrons inside the silver layer will vibrate under the action of the electromagnetic wave, converting the energy of the electromagnetic wave into heat energy. This is the absorption effect of the silver layer on the electromagnetic wave. The shielding efficiency of the silver layer is very high, and it can effectively shield electromagnetic waves in a wide frequency range. The shielding effect of the silver layer is related to its thickness, surface treatment and the frequency of the electromagnetic wave.

[0056] In some embodiments, the thickness of the silver layer may be 0.1 micron to 0.5 micron. In this case, since the shielding effect of the silver layer is related to the thickness of the silver layer, the shielding effect of the silver layer on the target 2 may be improved by appropriately increasing the thickness of the silver layer. Preferably, the thickness of the silver layer may be 0.1 micron to 0.2 micron. Thus, by designing the thickness of the silver layer to be 0.1 micron to 0.2 micron, the overall thickness of the electromagnetic shielding film 1 can be kept within a reasonable range, while reducing the cost.

[0057] In some embodiments, the shielding layer 30 may include at least one of a nickel layer, a copper layer, and a silver layer. For example, the shielding layer 30 may be a combination of a nickel layer and a silver layer, a combination of a copper layer and a silver layer, or a combination of a nickel layer, a copper layer, and a silver layer. In this case, the shielding layer 30 can have more options, and the shielding layer 30 can fully integrate the excellent performance of the nickel layer, the copper layer, or the silver layer and the electromagnetic shielding performance.

[0058] In some embodiments, the nickel layer, copper layer or silver layer can be formed directly on the insulating layer by physical or chemical methods. In some embodiments, the nickel layer, copper layer or silver layer can be formed on the insulating layer 20 by surface treatment techniques such as chemical plating, physical vapor deposition (PVD) or chemical vapor deposition (CVD).

[0059] Although the shielding layer 30 is a nickel layer, a copper layer, a silver layer or a combination thereof in the above examples, it is understandable that the shielding layer 30 in the present invention can also be made of other metal materials. In some embodiments, the shielding layer 30 can be made of at least one of gold (Au), silver (Ag), copper (Cu), iron (Fe), aluminum (Al), nickel (Ni), titanium (Ti), and chromium (Cr).

[0060] In addition, in some embodiments, the shielding layer 30 may include an alloy made of a first metal and a second metal. In other words, the shielding layer 30 may be made of an alloy made of a first metal and a second metal. In some embodiments, the first metal and the second metal may be different. It should be noted that the term "including" here means that the shielding layer 30 is not limited to an alloy made of the first metal and the second metal, but may also be an alloy made of multiple metals.

[0061] In addition, in some embodiments, the shielding layer 30 may include an alloy made of more than two metals (such as a first metal, a second metal, a third metal, etc.). In other words, the shielding layer 30 may be made of an alloy made of more than two metals, wherein the material of each metal may be different from each other.

[0062] In this case, when the shielding layer 30 is made of an alloy of multiple different metals, the excellent physical and chemical properties of each metal in the alloy can be fully utilized to improve the physical and chemical properties of the shielding layer 30 .

[0063] In some embodiments, the shielding layer 30 may include an alloy made of a first metal with strong conductivity and a second metal with strong adhesion. The first metal and the second metal may be different. In this case, the shielding layer 30 can have both excellent conductivity and adhesion properties, thereby enhancing the shielding performance of the shielding layer 30 against electromagnetic waves, and can make the shielding layer 30 have excellent adhesion with the insulating layer 20 and the conductive adhesive layer 40, so that the electromagnetic shielding film 1 can prevent the layers from falling off when in use.

[0064] Although the above examples take into account the conductivity and adhesion properties, the present invention is not limited thereto. The concept of the present invention is to enable the alloy made of multiple metals to fully take into account the excellent physical and chemical properties of each metal in the alloy, so that the prepared shielding layer 30 and electromagnetic shielding film 1 can have excellent physical and chemical properties.

[0065] For example, in some embodiments, the oxidation resistance of the metal can also be considered. Thus, the shielding layer 30 prepared can be less susceptible to oxidation, thereby making the electromagnetic shielding film 1 durable. In some embodiments, the melting point of the metal can also be considered. Thus, the operating cost of the manufacturing equipment can be reduced, and the metal can be easily evaporated and then deposited on the insulating layer 20, thereby forming the shielding layer 30 on the insulating layer 20. Examples are not given here one by one.

[0066] In some embodiments, the shielding layer 30 may be made by an induction evaporation coating process, which may be implemented by an induction evaporation coating machine.

[0067] In some embodiments, the induction evaporation coating machine may include a vacuum chamber, a crucible, an evaporation source, and a condenser. The crucible may be disposed in the vacuum chamber for storing the alloy. The evaporation source may melt and evaporate the alloy. The condenser may condense the evaporated alloy vapor and deposit it on one side of the insulating layer 20. In this case, the alloy vapor may be gradually guided and deposited on the insulating layer 20 in the vacuum chamber. Compared with the prior art method of using a combination of a magnetron sputtering coating process and a water plating process, the deposition thickness (i.e., the film thickness of the shielding layer 30) may be controlled by controlling the temperature, pressure, or deposition time in the vacuum chamber, and the film thickness of the shielding layer 30 may be easily controlled and the manufacturing cost may be reduced.

[0068] In some embodiments, the crucible may be made of a material with a higher melting point than the alloy. For example, the crucible may be made of a metal material with a high melting point, such as tungsten (W) or molybdenum (Mo). Thus, the crucible can be prevented from being damaged when the temperature is increased.

[0069] In some embodiments, the physical and chemical properties of the shielding layer 30 can be improved by adjusting the content of various metals in the alloy.

[0070] In some embodiments, the first metal may be selected from one of gold (Au), silver (Ag), copper (Cu), iron (Fe), aluminum (Al), nickel (Ni), and titanium (Ti). These metals all have excellent electrical conductivity. When these metals are included in the alloy, the electromagnetic shielding performance of the shielding layer 30 can be enhanced. Of course, it is not limited to this. For example, nickel has excellent anti-oxidation performance and low price compared to other metals. By adding nickel to the alloy, the durability of the electromagnetic shielding film can be enhanced (not easy to be oxidized), and the manufacturing cost of the electromagnetic shielding film can be reduced.

[0071] In some embodiments, the second metal can be selected from one of gold (Au), silver (Ag), copper (Cu), aluminum (Al), nickel (Ni), titanium (Ti), and chromium (Cr). These metals have excellent adhesion. When these metals are included in the alloy, the shielding layer 30 can enhance the adhesion with other layers (insulating layer 20, conductive adhesive layer 40, etc.), and the shielding layer 30 is not easy to fall off, thereby enhancing the durability of the electromagnetic shielding film.

[0072] Preferably, the alloy in the present invention is preferably a copper-nickel alloy, a silver-nickel alloy, a gold-nickel alloy, etc. In this case, the alloy can make full use of the excellent electrical conductivity of gold, silver and copper, as well as the anti-oxidation performance, strong adhesion performance and price advantage of nickel.

[0073] In some embodiments, the contents of the various metals in the alloy may be the same or different.

[0074] In some embodiments, the content of the first metal in the alloy may be 10%-90%, and the content of the second metal may be 90%-10%. Thus, by adjusting the content of each metal in the alloy, the overall performance of the alloy can be integrated to maintain the overall performance of the alloy at an excellent level.

[0075] In some embodiments, when the alloy is a copper-nickel alloy, the copper content can account for 10%-90% and the nickel content can account for 90%-10% when the alloy is mixed. Preferably, the copper and nickel contents can account for 50% respectively. The contents of various metals in other alloys are not listed here one by one, and can be mixed according to the required performance of the electromagnetic shielding film.

[0076] In some embodiments, the shielding layer 30 may further include carbon materials such as graphene and silicon carbide (SiC), thereby further enhancing the electromagnetic shielding performance of the shielding layer 30 .

[0077] In some embodiments, the thickness of the shielding layer 30 may be 0.1 micron to 2 microns. Preferably, the thickness of the shielding layer 30 may be 0.5 micron to 1.5 microns. In other words, the overall thickness of the shielding layer 30 may be maintained between 0.1 micron and 2 microns. Preferably, the overall thickness of the shielding layer 30 may be maintained between 0.5 micron and 1.5 microns. Thus, the overall thickness of the electromagnetic shielding film can be maintained within a reasonable thickness range.

[0078] In some embodiments, the electromagnetic shielding film may include a conductive adhesive layer 40. The conductive adhesive layer 40 may be configured to fit closely with the shielding layer 30. In some embodiments, the conductive adhesive layer 40 may also be configured to fit closely with the shielding layer 30 and the second base layer 50. In some embodiments, the conductive adhesive layer 40 may also be configured to adhere to the target 2. In some embodiments, the conductive adhesive layer 40 may also be configured to shield the electromagnetic radiation generated by the target 2 during operation.

[0079] In some embodiments, the shielding layer 30 and the conductive adhesive layer 40 may be configured to absorb electromagnetic waves generated by the target object 2 and thereby shield the electromagnetic waves generated by the target object 2 .

[0080] In some embodiments, the conductive adhesive layer 40 may be disposed on a side of the shielding layer 30 away from the insulating layer 20 .

[0081] In some embodiments, the conductive adhesive layer 40 may be disposed toward the target object 2 and then adhered to the target object 2 .

[0082] In some embodiments, the electromagnetic shielding film 1 may include a conductive adhesive layer 40, a shielding layer 30 and an insulating layer 20. In other words, the electromagnetic shielding film may adhere the structure composed of the conductive adhesive layer 40, the shielding layer 30 and the insulating layer 20 to the target 2 when in use.

[0083] In some embodiments, the thickness of the conductive adhesive layer 40 may be 1 micrometer to 15 micrometers. Preferably, the thickness of the conductive adhesive layer 40 may be 4 micrometers to 7 micrometers.

[0084] In some embodiments, the conductive adhesive layer 40 may be configured to tightly combine the second base layer 50 and the shielding layer 30 .

[0085] In some embodiments, after the second base layer 50 is removed, the adhesiveness of the conductive adhesive layer 40 may be utilized to make at least a portion of the electromagnetic shielding film adhere to the target 2 .

[0086] In some embodiments, the conductive adhesive layer 40 may include glue. In some embodiments, the glue may be made of a mixture of epoxy resin and a curing agent. In some embodiments, the glue may be made of at least one of modified epoxy resin, modified acrylic resin, and modified thermoplastic polyimide resin.

[0087] In some embodiments, the conductive adhesive layer 40 may include a conductive material. In some embodiments, the conductive material may include at least one of metal particles, conductive fibers, and conductive polymers. In this case, the use of the conductive material can improve the electromagnetic shielding performance of the conductive adhesive layer 40 (the electromagnetic shielding principle of the conductive material is described in the nickel layer 31, the copper layer 32, and the silver layer 33, which will not be repeated here).

[0088] In some embodiments, the conductive adhesive layer 40 may be made by coating conductive adhesive on the shielding layer 30. In some embodiments, the conductive adhesive may be made by mixing a curing agent, epoxy resin, and conductive particles.

[0089] In some embodiments, the conductive material may be uniformly dispersed in the glue to form the conductive glue layer 40 , thereby further improving the electromagnetic shielding effect of the conductive glue layer 40 .

[0090] Figure 2 It is a structural diagram of Example 1 of the electromagnetic shielding film 1 of the present invention. Figure 3 It is a structural diagram of Example 2 of the electromagnetic shielding film 1 of the present invention.

[0091] Reference Figure 2 and Figure 3 In some embodiments, the electromagnetic shielding film 1 may further include a first base layer 10. The first base layer 10 may be configured to serve as a manufacturing substrate for the electromagnetic shielding film 1. Of course, after the electromagnetic shielding film 1 is manufactured, the first base layer 10 as the outermost layer of the electromagnetic shielding film 1 can also prevent the electromagnetic shielding film 1 from being scratched or damaged.

[0092] In some embodiments, the first base layer 10 may be configured to be bonded to the target object 2. In other words, the electromagnetic shielding film may be bonded to the target object 2 through the first base layer 10. The first base layer 10 may be bonded to the target object 2 by, for example, applying glue on the first base layer 10 or the target object 2, and then bonding the first base layer 10 to the target object 2.

[0093] In some embodiments, the thickness of the first base layer 10 may be 10 micrometers to 100 micrometers. Preferably, the thickness of the first base layer 10 may be 50 micrometers.

[0094] In some embodiments, the first base layer 10 may be disposed on a side of the insulating layer 20 away from the shielding layer 30 .

[0095] In some embodiments, the first base layer 10 may include a non-silicon release agent. The first base layer 10 may be made by coating the non-silicon release agent on a mold. Compared with traditional silicon-based release agents, non-silicon release agents have better environmental performance and lower peeling force, and can facilitate the subsequent production of the insulating layer 20, the shielding layer 30, etc. on the basis of the first base layer 10.

[0096] In some embodiments, the first base layer 10 may include a release curing agent. The release curing agent may be used for curing a non-silicon release agent. In some embodiments, the components of the release curing agent may include silicone, acrylate, toluene, and a platinum catalyst, etc. Toluene may be used as a solvent to mix and transport reactants, and the platinum catalyst may be used to accelerate the curing reaction and improve the curing efficiency.

[0097] In some embodiments, the first base layer 10 may be made by mixing a non-silicone release agent and a release curing agent.

[0098] Reference Figure 3 In some embodiments, a release agent may be applied between the first base layer 10 and the insulating layer 20. The release agent may form a first release layer 15. In some embodiments, the release agent may be applied to a side of the first base layer 10 close to the insulating layer 20, and then the first base layer 10 and the insulating layer 20 may be attached. Thus, the insulating layer 20 and the first base layer 10 may be easily separated. For example, when the electromagnetic shielding film 1 is used, the first base layer 10 may be torn off before use.

[0099] In some embodiments, the first base layer 10 may be removed when the electromagnetic shielding film 1 is used.

[0100] In some embodiments, the electromagnetic shielding film 1 may further include a second base layer 50. The second base layer 50 may be configured as a protective layer to reduce damage to the electromagnetic shielding film 1. For example, it may reduce scratches and damage to the electromagnetic shielding film 1 during transportation.

[0101] In some embodiments, the second base layer 50 may be disposed on a side of the conductive adhesive layer 40 away from the shielding layer 30 .

[0102] In some embodiments, a release agent may be applied between the second base layer 50 and the conductive adhesive layer 40. The release agent may form a second release layer 45. In some embodiments, the release agent may be applied on one side of the second base layer 50 close to the conductive adhesive layer 40, and then the second base layer 50 and the conductive adhesive layer 40 are bonded.

[0103] In some embodiments, the material of the second base layer 50 can be PET (polyethylene terephthalate), PE (polyethylene), PP (polypropylene), PVC (polyvinyl chloride), PBT (polybutylene terephthalate), PEF (polyethylene furanoate), PU (polyurethane), etc.

[0104] In some embodiments, the second base layer 50 may have a thickness of 10 micrometers to 100 micrometers. Preferably, the second base layer 50 may have a thickness of 50 micrometers to 75 micrometers.

[0105] In some embodiments, the first base layer 10 , the insulating layer 20 , the shielding layer 30 , the conductive adhesive layer 40 , and the second base layer 50 may be disposed in sequence.

[0106] Figure 4 This is a flow chart of Example 1 of the method for producing the electromagnetic shielding film 1 of the present invention. Figure 5 This is a flow chart of Example 2 of the method for producing the electromagnetic shielding film 1 of the present invention.

[0107] Reference Figure 4 In some embodiments, the preparation method may include step S200 of preparing an insulating layer 20 .

[0108] In some embodiments, step S200 may include: preparing epoxy resin, curing agent, and carbon black.

[0109] In some embodiments, the weight ratio of epoxy resin, curing agent and carbon black can be 100:5:1.

[0110] In some embodiments, based on weight, the epoxy resin may be 70 to 100 parts, the curing agent may be 0.8 to 3.5 parts, and the carbon black may be 0.05 to 0.2 parts.

[0111] In some embodiments, step S200 may include: stirring epoxy resin, curing agent and carbon black to form a viscous, slurry-like insulating adhesive.

[0112] In some embodiments, the epoxy resin, curing agent and carbon black may be added into a mixer and dispersed and stirred for 10 minutes to form a viscous, slurry-like insulating adhesive.

[0113] In some embodiments, the preparation method may include step S300 , preparing a shielding layer 30 on the surface of the insulating layer 20 .

[0114] Specifically, alloy vapor may be deposited on one side of the insulating layer 20 by an induction evaporation coating process to form the shielding layer 30 on one side of the insulating layer 20 .

[0115] In some embodiments, the shielding layer may include an alloy made of a first metal with strong conductivity and a second metal with strong adhesion. The first metal and the second metal may be different.

[0116] For the introduction of alloys, please refer to the above and will not be repeated here.

[0117] The specific process flow of depositing alloy vapor on one side of the insulating layer 20 by the induction evaporation coating process may include: (1) Preparation before plating: including cleaning the fixture, the supporting device (the device that supports the first base layer 10 and the insulating layer 20), the crucible and other components. (2) Vacuuming: Open the cooling water valve, connect the main power supply, close the atmospheric valve leading to the vacuum chamber, start the mechanical pump power supply, and evacuate to achieve the required vacuum degree. (3) Ion bombardment: Under a certain vacuum degree, use ion bombardment to clean the surface of the insulating layer 20 to improve the bonding force of the surface of the insulating layer 20. (4) Pre-melting: Pre-melt the alloy in the crucible to remove low-melting impurities and adsorbed gases to prepare for the evaporation process. (5) Evaporation: Heat the alloy to the evaporation temperature to vaporize it. (6) Cooling: Cool the alloy vapor so that the alloy vapor is deposited on the surface of the insulating layer 20 to form the shielding layer 30.

[0118] In some embodiments, the preparation method may include step S400, preparing a conductive adhesive layer 40 on the surface of the shielding layer 30. In some embodiments, a conductive adhesive may be applied on a side of the shielding layer 30 away from the insulating layer 20 to form a conductive adhesive layer 40 on one side of the shielding layer 30.

[0119] In some embodiments, step S400 may include: preparing epoxy resin, curing agent and conductive particles, and stirring the epoxy resin, curing agent and conductive particles to form a viscous or slurry-like conductive adhesive.

[0120] In some embodiments, the epoxy resin, curing agent, and conductive particles may be selected in a weight ratio of 200:1:100. The conductive particles may include one or more of copper, iron, nickel, zinc, silver alloy, copper alloy, iron alloy, nickel alloy, and zinc alloy.

[0121] In some embodiments, the conductive particles may be conductive nickel powder or conductive copper powder.

[0122] In some embodiments, in the conductive adhesive, the epoxy resin may be 70 to 100 parts, the curing agent may be 0.8 to 3.5 parts, and the conductive nickel powder may be 30 to 60 parts by weight.

[0123] In some embodiments, epoxy resin, curing agent, and conductive particles may be put into a mixer and dispersed and stirred for 10 minutes to form a viscous, slurry-like conductive adhesive.

[0124] In some embodiments, step S400 may include: coating a conductive adhesive on the surface of the copper layer 32 to form a conductive adhesive layer 40 on the surface of the copper layer 32 , and drying and curing the conductive adhesive layer 40 at room temperature.

[0125] Reference Figure 5 In some embodiments, the preparation method may include step S100 of preparing a first base layer 10 .

[0126] In some embodiments, an insulating glue may be coated on the surface of the first base layer 10 to form the insulating layer 20 on the first base layer 10 .

[0127] In some embodiments, the material of the first base layer 10 can be PET (polyethylene terephthalate), PE (polyethylene), PP (polypropylene), PVC (polyvinyl chloride), PBT (polybutylene terephthalate), PEF (polyethylene furanoate), PU (polyurethane), etc.

[0128] In some embodiments, the preparation method may include step S500 , preparing a second base layer 50 , and laminating a side of the conductive adhesive layer 40 away from the shielding layer 30 to the second base layer 50 .

[0129] Specifically, the conductive adhesive layer 40 has strong adhesiveness, and the conductive adhesive layer 40 can be bonded to the second base layer 50 .

[0130] In some embodiments, the material of the second base layer 50 can be PET (polyethylene terephthalate), PE (polyethylene), PP (polypropylene), PVC (polyvinyl chloride), PBT (polybutylene terephthalate), PEF (polyethylene furanoate), PU (polyurethane), etc.

[0131] The following shows the test results of three samples of electromagnetic shielding films (hereinafter referred to as sample 1, sample 2 and sample 3). Table 1 shows the parameter values ​​of different layers of the three samples, and Table 2 shows the product performance of the three samples under different parameter values.

[0132]

[0133] Table 1

[0134] The total adhesive thickness is the thickness of the electromagnetic shielding film after removing the first base layer 10 and the second base layer 20 .

[0135]

[0136] Table 2

[0137] It can be seen from Table 1 and Table 2 that the shielding performance of the electromagnetic shielding film can be enhanced by appropriately increasing the thickness of the shielding layer 30 and / or the conductive adhesive layer 40. The electromagnetic shielding film of the present invention has good bending resistance, insulation, chemical resistance, and a small grounding resistance, is halogen-free, and meets environmental protection requirements.

[0138] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention 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 of the technical features may be replaced by equivalents, and these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. An electromagnetic shielding film, wherein the electromagnetic shielding film is configured to be attached to a target object to shield electromagnetic radiation generated by the target object during operation, characterized in that: It includes a first base layer, an insulating layer, a shielding layer, a conductive adhesive layer and a second base layer which are arranged in sequence, wherein the conductive adhesive layer is configured to enhance adhesion with the shielding layer and the target object, and the conductive adhesive layer and the shielding layer are configured to shield electromagnetic radiation generated by the target object during operation, wherein the shielding layer includes an alloy made of a first metal with strong conductivity and a second metal with strong adhesion, and the first metal is different from the second metal, and the shielding layer is made of an induction evaporation coating process.

2. The electromagnetic shielding film according to claim 1, characterized in that The first metal is selected from one of gold, silver, copper, iron, aluminum, nickel, and titanium, and the second metal is selected from one of gold, silver, copper, aluminum, nickel, titanium, and chromium.

3. The electromagnetic shielding film according to claim 1, characterized in that The content of the first metal in the alloy is 10%-90%, and the content of the second metal is 90%-10%.

4. The electromagnetic shielding film according to claim 1, characterized in that The thickness of the shielding layer is 0.1 micrometer to 2 micrometers.

5. The electromagnetic shielding film according to claim 1, characterized in that The conductive adhesive layer is made by coating conductive adhesive on the shielding layer.

6. The electromagnetic shielding film according to claim 5, characterized in that The conductive adhesive is prepared by mixing a curing agent, epoxy resin and conductive particles.

7. The electromagnetic shielding film according to claim 1, characterized in that A release agent is coated between the first base layer and the insulating layer, and the first base layer is removed when the electromagnetic shielding film is used.

8. The electromagnetic shielding film according to claim 1, characterized in that A release agent is coated between the second base layer and the conductive adhesive layer. The second base layer is removed when the electromagnetic shielding film is used. After the second base layer is removed, at least a portion of the electromagnetic shielding film is adhered to a target object using the adhesion of the conductive adhesive layer.

9. A method for preparing an electromagnetic shielding film, characterized in that: The method comprises: Prepare the first base layer; Applying insulating glue on one side of the first base layer to form an insulating layer on the first base layer; Depositing alloy vapor on one side of the insulating layer by an induction evaporation coating process to form a shielding layer on one side of the insulating layer, wherein the shielding layer comprises an alloy made of a first metal with strong conductivity and a second metal with strong adhesion, and the first metal is different from the second metal; Applying conductive glue on a side of the shielding layer away from the insulating layer to form a conductive glue layer on one side of the shielding layer; A second base layer is prepared, and a side of the conductive adhesive layer away from the shielding layer is bonded to the second base layer.

10. The method for preparing an electromagnetic shielding film according to claim 9, characterized in that: The steps of preparing the conductive adhesive layer include: Preparing epoxy resin, curing agent and conductive particles, and stirring the epoxy resin, the curing agent and the conductive particles to form a viscous, slurry-like conductive adhesive; The conductive adhesive is coated on the surface of the shielding layer to form the conductive adhesive layer on the surface of the shielding layer, and then dried and cured at room temperature.

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