Electromagnetic shielding tape and its preparation method and application

Abstract

The present application relates to the field of electronic components, and more specifically, it relates to an electromagnetic shielding tape and its preparation method and application. It includes a conductive layer and at least one shielding pressure-sensitive layer, each of which is connected to the conductive layer, and each of which is provided with a protective layer on the side away from the conductive layer, and the gram weight of each shielding pressure-sensitive layer accounts for 100-166% of the gram weight of the conductive layer, and the shielding pressure-sensitive layer is formed by coating and curing a conductive acrylic pressure-sensitive adhesive. The conductive acrylic pressure-sensitive adhesive has good flexibility, conductivity, film-forming stability and adhesion stability. When the gram weight of the shielding pressure-sensitive layer accounts for 100-166% of the gram weight of the conductive layer, the shielding pressure-sensitive layer has good adhesion, so that it has good adhesion stability with the conductive layer, and has good adhesion to the circuit board, reducing the possibility of falling off and cracking, so that the electromagnetic shielding tape obtains a better electromagnetic shielding effect.

Description

Technical Field

[0001] The present application relates to the field of electronic components, and more specifically, to an electromagnetic shielding tape and a preparation method and application thereof. Background Art

[0002] With the development of miniaturization and ultra-thinness of electronic products, the circuit board configuration is also becoming more and more miniaturized and ultra-thin, which can meet the design needs of smaller and higher density electronic products, and also help to reduce assembly processes and enhance reliability.

[0003] Circuit boards are not only required to be miniaturized and ultra-thin, but also have good insulation properties and high-frequency electrical signal transmission performance. In recent years, the high-frequency and high-speed internal components of mobile phones and other communication equipment have caused electromagnetic interference inside and outside the components, and signal attenuation during transmission has become increasingly serious. Therefore, the shielding function requirements for circuit boards are getting higher and higher.

[0004] At present, electromagnetic interference can be effectively suppressed by covering the circuit board with electromagnetic shielding film or electromagnetic shielding tape, reducing the attenuation of the transmission signal in the circuit board and improving the integrity of the transmission signal. The electromagnetic shielding tape is usually composed of an adhesive layer and a conductive layer, wherein the adhesive layer is stably connected to the conductive layer, and the electromagnetic shielding tape is stably adhered to the circuit board through the bonding effect of the adhesive layer, while the conductive layer plays a better electromagnetic shielding role, reducing the possibility of electromagnetic interference in the circuit board.

[0005] However, the electromagnetic shielding tape still debonds during use, thereby reducing the bonding stability of the electromagnetic shielding tape on the circuit board, causing the circuit board to warp, shift, fall off, etc. during use, affecting the overall shielding efficiency of the circuit board.

[0006] Related technologies include providing protruding structures on both the adhesive layer and the conductive layer and interlocking the protruding structures of the adhesive layer and the conductive layer to improve the connection stability between the adhesive layer and the conductive layer. However, there is still a problem of adhesion instability when adhering to the circuit board. The adhesive layer is usually formed by curing an acrylic pressure-sensitive adhesive. Although it has good adhesion, due to its insulating properties, it hinders the uniformity of electromagnetic shielding on the surface of the conductive layer, thereby affecting the overall electromagnetic shielding effect of the electromagnetic shielding tape. Summary of the invention

[0007] In order to obtain better electromagnetic shielding adhesive layer structural stability, bonding stability to circuit boards and electromagnetic shielding effect, the present application provides an electromagnetic shielding tape and a preparation method and application thereof.

[0008] In the first aspect, the present application provides an electromagnetic shielding tape, comprising a conductive layer and at least one shielding pressure-sensitive layer, each of the shielding pressure-sensitive layers being connected to the conductive layer, a protective layer being provided on a side of each of the shielding pressure-sensitive layers away from the conductive layer, the gram weight of each of the shielding pressure-sensitive layers accounting for 100-166% of the gram weight of the conductive layer, and the shielding pressure-sensitive layer being formed by coating and curing a conductive acrylic pressure-sensitive adhesive.

[0009] In the above technical solution, the conductive acrylic pressure-sensitive adhesive has better flexibility, conductivity, film-forming stability and adhesion stability. When the weight of the shielding pressure-sensitive layer accounts for 100-166% of the weight of the conductive layer, the shielding pressure-sensitive layer has better adhesion, which makes it have better adhesion stability with the conductive layer and has better adhesion to the circuit board, reducing the possibility of falling off and cracking, so that the electromagnetic shielding tape has better electromagnetic shielding effect.

[0010] Preferably, the conductive acrylic pressure-sensitive adhesive is composed of the following raw materials in parts by weight:

[0011] Acrylate flexible monomer 2-5 parts

[0012] 3-5 parts of silicone acrylate

[0013] Isocyanate acrylate 1-3 parts

[0014] Initiator 0.1-0.5 parts

[0015] 1-3 parts Ag-Fe3O4 powder

[0016] 20-30 parts of solvent.

[0017] Preferably, the conductive acrylic pressure-sensitive adhesive is prepared by the following method:

[0018] According to the weight, weigh the acrylic ester flexible monomer, initiator and 1 / 2 solvent and mix them evenly, heat to 62-72°C, react for 30-50 minutes, then add siloxy acrylate, react for 30-50 minutes, then add isocyanate acrylate and react for 2-3 hours; then add 1 / 2 solvent, stir evenly at a speed of 100-200r / min, and then add Ag-Fe 3 O 4 Powder, continue stirring for 10-20 minutes to obtain a conductive acrylic pressure-sensitive adhesive.

[0019] In the above technical scheme, the acrylate flexible monomer undergoes self-polymerization under the action of an initiator to obtain a polymer, and the added siloxy acrylate undergoes a one-step reaction under the action of the remaining initiator, and introduces siloxy groups into the polymer, and the added isocyanate acrylate is further reacted under the action of the initiator to obtain a macromolecular cross-linked network polymer, and the macromolecular cross-linked network polymer has better flexibility, compatibility with inorganic substances, adhesion, etc.

[0020] Ag-Fe 3 O 4 The powder has good electrical conductivity and magnetic attraction, and plays the role of filling reinforcement, viscosity enhancement, etc. It has good compatibility with macromolecular cross-linked network polymers, so that the raw material system of conductive acrylic pressure-sensitive adhesive is evenly dispersed and tightly connected with the molecular structure of acrylic pressure-sensitive adhesive, thereby making the conductive acrylic pressure-sensitive adhesive have better adhesion, flexibility, film-forming properties, conductivity and magnetic attraction.

[0021] When the conductive acrylic pressure-sensitive adhesive is coated on the surface of the conductive layer, it can stably adhere to the surface of the conductive layer. After curing, the shielding pressure-sensitive layer formed is stably connected to the conductive layer and has better peeling force. When applied to circuit boards, it reduces the possibility of falling off and has better flexibility. After being folded many times, it is not easy to break, crack, debond and other possible properties. It cooperates with the conductive layer to further improve the electromagnetic shielding effect of the electromagnetic shielding tape. When used in circuit boards, it has better electromagnetic shielding effect and adhesion stability.

[0022] Preferably, the acrylic ester flexible monomer is one or more of lauryl methacrylate, 2-ethylhexyl acrylate, and glycidyl methacrylate.

[0023] Lauryl methacrylate, 2-ethylhexyl acrylate, and glycidyl methacrylate can all undergo self-polymerization to form polymers with better softness and toughness, and can further react with siloxy acrylate and isocyanate acrylate to form macromolecular cross-linked network polymers, and react with Ag-Fe 3 O 4 The powder is compounded to make the prepared conductive acrylic pressure-sensitive adhesive raw material system fully mixed and uniform, and the molecular structure of the shielding pressure-sensitive layer formed after curing is tightly connected and has better flexibility, adhesion, conductivity, peeling force and magnetic attraction. Therefore, with the conductive layer, the obtained electromagnetic shielding tape has better electromagnetic shielding effectiveness, adhesion stability, structural stability and flexibility.

[0024] When lauryl methacrylate, 2-ethylhexyl acrylate and glycidyl methacrylate are compounded, they play a synergistic role and cooperate with other materials to make the electromagnetic shielding tape produced by the prepared conductive acrylic pressure-sensitive adhesive have better flexibility, adhesion and shielding effectiveness.

[0025] Preferably, the siloxy acrylate is 2-(trimethylsiloxy)ethyl methacrylate and / or 3-trimethoxysilane propyl acrylate.

[0026] 2-(Trimethylsilyloxy)ethyl methacrylate and 3-trimethoxysilyl acrylate can be further cross-linked with acrylate flexible monomers and isocyanate acrylate to form cross-linked macromolecular polymers, and then react with Ag-Fe 3 O 4 The powders have good compatibility, so that the prepared shielding pressure-sensitive adhesive layer has better shielding performance, flexibility, adhesion stability and magnetic attraction.

[0027] When 2-(trimethylsilyloxy)ethyl methacrylate and 3-trimethoxysilane acrylate are compounded, a synergistic effect is achieved, so that the prepared shielding pressure-sensitive adhesive layer has better shielding performance, flexibility and adhesion stability.

[0028] Preferably, the isocyanate acrylate is isocyanate ethyl acrylate and / or isocyanate ethyl methacrylate.

[0029] Isocyanoethyl acrylate and / or isocyanoethyl methacrylate can further crosslink with siloxy acrylate and acrylic soft monomer, and then with Ag-Fe 3 O 4 The shielding pressure-sensitive adhesive layer prepared by the powder has better shielding performance, flexibility, adhesion stability and magnetic attraction.

[0030] Preferably, the Ag-Fe 3 O 4 The powder consists of Ag-Fe3O4 powder with the following particle size ranges:

[0031] Particle size is 10-50nmAg-Fe 3 O 4 1-5 servings of powder

[0032] Particle size is 80-150nmAg-Fe 3 O 4 1-4 servings of powder

[0033] Particle size is 200-300nmAg-Fe 3 O 4 2-5 parts powder.

[0034] When using Ag-Fe 3 O 4The powder is compounded to make the fillings between the fillers tightly, and it plays a better filling and viscosity-increasing role on the conductive acrylic pressure-sensitive adhesive. It is then combined with a cross-linked network polymer made of acrylate flexible monomer, silicone acrylate, and isocyanate acrylate to make the electromagnetic shielding tape have better flexibility, electromagnetic shielding effect and adhesion.

[0035] Preferably, the conductive layer is a non-woven conductive fabric.

[0036] The surface of non-woven conductive fabric is uneven and has many pores. When conductive acrylic pressure-sensitive adhesive is applied, it can easily penetrate into the pores and flatten the uneven surface, so that the shielding pressure-sensitive layer obtained after curing is tightly connected to the conductive layer, thereby improving the layer structure stability of the electromagnetic shielding tape and obtaining better softness.

[0037] Preferably, the non-woven conductive layer is a nickel-copper non-woven conductive fabric.

[0038] The nickel-copper non-woven conductive fabric has good conductivity and is easy to adsorb or adhere to the conductive acrylic pressure-sensitive adhesive, thereby further improving the adhesion stability between the prepared shielding pressure-sensitive layer and the nickel-copper non-woven fabric. The possibility of folding and degumming of the electromagnetic shielding tape during multiple folding processes is reduced, and the practicality of the electromagnetic shielding tape is improved.

[0039] Preferably, the method comprises the following steps:

[0040] The conductive cloth is flattened to obtain a conductive layer; a conductive acrylic pressure-sensitive adhesive is coated on at least one side of the conductive layer, and after curing, a shielding pressure-sensitive layer is formed on at least one side of the conductive layer, and a protective layer is adhered to the side of each shielding pressure-sensitive layer away from the conductive layer to obtain an electromagnetic shielding tape.

[0041] In a second aspect, the present application provides an application of an electromagnetic shielding tape, wherein the electromagnetic shielding tape is applied to a flexible circuit board.

[0042] Flexible circuit boards are the only solution to meet the requirements of miniaturization and mobility of electronic products. They can be bent, wound, and folded freely, and can withstand millions of dynamic bendings without damaging the wires. The electromagnetic shielding tape of the present application has better adhesion, flexibility, and electromagnetic shielding effect. Therefore, after multiple bending, winding, and folding, it is not easy to crack, fall off, warp, etc., thereby improving the practicality of the electromagnetic shielding tape.

[0043] The electromagnetic shielding tape of the present application is used for a flexible circuit board with a nickel-plated surface to achieve a better adhesion effect, thereby reducing the possibility of warping and the like.

[0044] In summary, this application has the following beneficial effects:

[0045] 1. Conductive acrylic pressure-sensitive adhesive has good flexibility, conductivity, film-forming stability and adhesion stability. When the weight of the shielding pressure-sensitive layer accounts for 100-166% of the weight of the conductive layer, the shielding pressure-sensitive layer has good adhesion, which makes it have good adhesion stability with the conductive layer and has good adhesion to the circuit board, reducing the possibility of falling off and cracking, and at the same time making the electromagnetic shielding tape have better electromagnetic shielding effect.

[0046] 2. When the conductive acrylic pressure-sensitive adhesive is coated on the surface of the conductive layer, it can stably adhere to the surface of the conductive layer. After curing, the shielding pressure-sensitive layer formed is stably connected to the conductive layer and has better peeling force. When applied to circuit boards, it reduces the possibility of falling off. At the same time, it has better flexibility and is not prone to breakage and cracking. It cooperates with the conductive layer to further improve the electromagnetic shielding effect of the electromagnetic shielding tape. When used in circuit boards, it has better electromagnetic shielding effect and adhesion stability. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] Attached Figure 1 A schematic diagram of the layer structure of an electromagnetic shielding tape of the present application.

[0048] Explanation of the reference numerals: 1. Conductive layer; 2. Shielding pressure-sensitive layer; 3. Protective layer. DETAILED DESCRIPTION

[0049] The present application is further described in detail below with reference to the embodiments.

[0050] The sources or performance parameters of some raw materials;

[0051] Table 1 Sources or performance parameters of some raw materials

[0052]

[0053] Example

[0054] Example 1

[0055] An electromagnetic shielding tape, reference Figure 1 , including a conductive layer 1 and at least one shielding pressure-sensitive layer 2, each shielding pressure-sensitive layer 2 is connected to the conductive layer 1, and each shielding pressure-sensitive layer 2 is provided with a protective layer 3 on a side away from the conductive layer 1. When the shielding pressure-sensitive layer 2 is a single layer, the shielding pressure-sensitive layer 2 is connected to one side of the conductive layer 1; when the shielding pressure-sensitive layer 2 is a two-layer layer, the two shielding pressure-sensitive layers 2 are respectively connected to the two surfaces of the conductive layer 1, so that both sides of the electromagnetic shielding tape have adhesion, and the embodiment preferably has a shielding pressure-sensitive layer on one side of the conductive layer.

[0056] Providing the protective layer 4 on the shielding pressure-sensitive layer 3 is beneficial to protecting the shielding pressure-sensitive layer 3 and reducing the adsorption of dust, impurities, etc.

[0057] The weight of the shielding pressure-sensitive layer 2 accounts for 100% of the weight of the conductive layer 1. The shielding pressure-sensitive layer 2 is formed by coating and curing the conductive acrylic pressure-sensitive adhesive. The weight of the conductive layer 1 is 100 g / m 2 The conductive layer 1 is a blended woven conductive fabric.

[0058] The preparation method of the electromagnetic shielding tape comprises the following steps:

[0059] The conductive cloth is flattened to obtain a conductive layer; a conductive acrylic pressure-sensitive adhesive is coated on at least one side of the conductive layer, and after curing, a shielding pressure-sensitive layer is formed on at least one side of the conductive layer, and a protective layer is adhered to the side of each shielding pressure-sensitive layer away from the conductive layer to obtain an electromagnetic shielding tape.

[0060] The conductive acrylic pressure-sensitive adhesive is obtained by uniformly mixing graphene and acrylic pressure-sensitive adhesive in a weight ratio of 1:10.

[0061] Example 2

[0062] The difference between Example 2 and Example 1 is that the gram weight of each shielding pressure-sensitive layer accounts for 146% of the gram weight of the conductive layer.

[0063] Example 3

[0064] The difference between Example 3 and Example 1 is that the gram weight of each shielding pressure-sensitive layer accounts for 166% of the gram weight of the conductive layer.

[0065] Example 4

[0066] The difference between Example 4 and Example 2 is that the conductive acrylic pressure-sensitive adhesive is prepared by the following method:

[0067] Weigh 2kg of acrylate flexible monomer, 0.1kg of initiator (a mixture of methyl ethyl ketone peroxide and isopropylbenzene hydroperoxide), and 10kg of solvent into a reactor and mix them evenly. Heat to 65°C and react for 50min. Then add 3kg of siloxy acrylate and react for 30min. Then add 1kg of isocyanate acrylate and react for 3h. Then add 10kg of solvent (ethyl acetate) and stir for 10min at a speed of 200r / min. Then add 1kg of Ag-Fe 3 O 4 Powder, continue stirring for 20 minutes to obtain a conductive acrylic pressure-sensitive adhesive.

[0068] The acrylate flexible monomer is lauryl methacrylate; the siloxy acrylate is 2-(trimethylsiloxy)ethyl methacrylate; and the isocyanate acrylate is isocyanoethyl acrylate.

[0069] Example 5

[0070] The difference between Example 5 and Example 4 is that the amount of raw materials used is different, specifically as follows: 3.5 kg acrylate flexible monomer, 0.3 kg initiator, 4 kg siloxy acrylate, 2 kg isocyanate acrylate, 25 kg solvent, 2 kg Ag-Fe 3 O 4 pink.

[0071] Example 6

[0072] The difference between Example 6 and Example 4 is that the amount of raw materials used is different, specifically 5 kg of acrylate flexible monomer, 0.3 kg of initiator, 4 kg of siloxy acrylate, 2 kg of isocyanate acrylate, 30 kg of solvent, 3 kg of Ag-Fe 3 O 4 pink.

[0073] Example 7

[0074] The difference between Example 7 and Example 5 is that the acrylic ester flexible monomer consists of 2 kg of lauryl methacrylate, 1 kg of 2-ethylhexyl acrylate, and 0.5 kg of glycidyl methacrylate.

[0075] Example 8

[0076] The difference between Example 8 and Example 7 is that the siloxy acrylate is composed of 2 kg 2-(trimethylsiloxy)ethyl methacrylate and 2 kg 3-trimethoxysilane propyl acrylate.

[0077] Example 9

[0078] The difference between Example 9 and Example 8 is that the isocyanate acrylate consists of 1.7 kg of isocyanoethyl acrylate and 0.3 kg of isocyanoethyl methacrylate.

[0079] Example 10

[0080] The difference between Example 10 and Example 9 is that: Ag-Fe 3 O 4 The powder is composed of Ag-Fe with an average particle size of 10nm 3 O 4 1kg powder, average particle size of 80nm Ag-Fe 3 O 4 0.5kg powder, average particle size of 200nm Ag-Fe 3 O 4 The powder consists of 0.5kg.

[0081] Embodiment 11

[0082] The difference between Example 11 and Example 10 is that: Ag-Fe3 O 4 The powder is composed of Ag-Fe with an average particle size of 35nm 3 O 4 0.8kg of powder, 0.8kg of Ag-Fe3O4 powder with an average particle size of 130nm, 0.8kg of Ag-Fe 3 O 4 The powder consists of 0.4kg.

[0083] Example 12

[0084] The difference between Example 12 and Example 10 is that: Ag-Fe 3 O 4 The powder is composed of Ag-Fe with an average particle size of 50nm 3 O 4 0.5kg of powder, 1.4kg of Ag-Fe3O4 powder with an average particle size of 150nm, and 300nm of Ag-Fe 3 O 4 The powder consists of 0.1kg.

[0085] Embodiment 13

[0086] The difference between Example 13 and Example 11 is that the conductive layer is a nickel-copper non-woven conductive cloth.

[0087] Embodiment 14

[0088] The difference between Example 14 and Example 4 is that the siloxy acrylate is replaced by an acrylate flexible monomer in equal amounts.

[0089] Embodiment 15

[0090] The difference between Example 15 and Example 4 is that an equal amount of isocyanate acrylate is replaced by an acrylate flexible monomer.

[0091] Example 16

[0092] The difference between Example 16 and Example 4 is that: Ag-Fe 3 O 4 The powder is replaced with graphene in equal amounts.

[0093] Application Examples

[0094] Application Example 1

[0095] The electromagnetic shielding tape obtained in Example 1 is applied to a flexible circuit board.

[0096] Application Example 2-16

[0097] The difference between Application Example 2-16 and Application Example 1 is that the source of the electromagnetic shielding tape is different, as shown in Table 2;

[0098] Table 2 Sources of electromagnetic shielding tapes for application examples 1-16

[0099] Application Examples Source of electromagnetic shielding tape Application Example 1 Example 1 Application Example 2 Example 2 Application Example 3 Example 3 Application Example 4 Example 4 Application Example 5 Example 5 Application Example 6 Example 6 Application Example 7 Example 7 Application Example 8 Example 8 Application Example 9 Example 9 Application Example 10 Example 10 Application Example 11 Embodiment 11 Application Example 12 Example 12 Application Example 13 Embodiment 13 Application Example 14 Embodiment 14 Application Example 15 Embodiment 15 Application Example 16 Example 16

[0100] Comparative Example

[0101] Comparative Example 1

[0102] The difference between Comparative Example 1 and Example 1 is that the gram weight of each shielding pressure-sensitive layer accounts for 50% of the gram weight of the conductive layer.

[0103] Comparative Example 2

[0104] The difference between Comparative Example 2 and Example 1 is that the gram weight of each shielding pressure-sensitive layer accounts for 200% of the gram weight of the conductive layer.

[0105] Comparative Example 3

[0106] The difference between Comparative Example 3 and Example 1 is that the conductive acrylic pressure-sensitive adhesive is acrylic pressure-sensitive adhesive.

[0107] Performance testing

[0108] Detection method / test method

[0109] 1. Resistance value

[0110] Refer to GB / T 1410-1989 for testing.

[0111] 2. Peel strength

[0112] Refer to GB / T 2792-2014 for testing

[0113] 3. Folding test

[0114] Tear off the protective film of the electromagnetic shielding tape obtained in Examples 1-16 and Comparative Examples 1-3, and adhere the shielding pressure-sensitive adhesive layer to a flexible PCB board (insulating resin: epoxy resin (EP); mechanical rigidity: flexible; substrate: copper; brand: VMANX; model: HX2P0012A0), press down with a force of 5N for 1 min, and then perform a bending test using a flexible board bending tester. Bend toward one side of the shielding pressure-sensitive adhesive layer. When the number of bendings reaches 100,000 times, pause the experiment and check whether the electromagnetic shielding tape has debonding, bubbling, warping, etc. If the above phenomena do not occur, continue the bending test, count 10,000 times each time, and stop the experiment. When the above phenomena occur, stop the experiment and record the number of bendings.

[0115] The above experiments 1-2 were tested 5 times respectively and the average value was taken;

[0116] Table 3 Experimental data of Examples 1-16 and Comparative Examples 1-3

[0117]

[0118]

[0119] Combining Example 1 and Comparative Examples 1-2 and Table 3, it can be seen that the folding times of Comparative Examples 1-2 are lower than that of Example 1, and the peel strength of Comparative Example 1 is as low as less than 10, and the resistance value of Comparative Example 2 is as high as 0.69Ω / inch 2 On the whole, through the ratio range of the gram weight of the shielding pressure-sensitive layer to the gram weight of the conductive layer in the present application, the electromagnetic shielding tape obtained has better performance, and thus has better adhesion to both the conductive layer and the circuit board, reducing the possibility of falling off during use.

[0120] Combining Example 1 and Comparative Example 3 and Table 3, it can be seen that the folding times and peel strength of Comparative Example 3 are lower than those of Example 1, and the resistance value is larger than that of Example 1, indicating that the conductive acrylic pressure-sensitive adhesive has better electromagnetic shielding effect, adhesion, peeling force, etc.

[0121] Combining Example 2 and Example 4 and Table 3, it can be seen that the folding endurance and peel strength of Example 4 are higher than those of Example 1, and the resistance value is smaller than that of Example 1, indicating that the conductive acrylic pressure-sensitive adhesive prepared using the raw materials of the present application has better shielding performance and is stably bonded to the conductive layer and the PBC board, reducing the possibility of cracking and warping.

[0122] Combining Example 7 with Example 5 and Table 3, it can be seen that the folding times and peel strength of Example 7 are higher than those of Example 5, and the resistance value is smaller than that of Example 5, indicating that the use of lauryl methacrylate, 1kg 2-ethylhexyl acrylate, and 0.5kg glycidyl methacrylate in the present application has a synergistic effect, and the combination of siloxy acrylate, isocyanate acrylate, and Ag-Fe 3 O 4 The powder makes the prepared conductive acrylic pressure-sensitive adhesive have better shielding performance and adhesion, and has stable bonding with the conductive layer and the PBC board, reducing the possibility of cracking and warping.

[0123] Combining Example 8 with Example 7 and Table 3, it can be seen that the folding times and peel strength of Example 8 are higher than those of Example 7, and the resistance value is smaller than that of Example 7, indicating that the use of 2-(trimethylsilyloxy)ethyl methacrylate and 3-trimethoxysilane acrylate plays a synergistic role, and then with acrylate flexible monomer, isocyanate acrylate, Ag-Fe 3 O 4The powder is compounded and polymerized, so that the conductive acrylic pressure-sensitive adhesive has better shielding performance and adhesion, and is stably bonded to the conductive layer and the PBC board, reducing the possibility of cracking and warping.

[0124] Combining Example 9 with Example 8 and Table 3, it can be seen that the peel strength of Example 9 is higher than that of Example 8, and the resistance value is smaller than that of Example 8, indicating that the use of isocyanoethyl acrylate and isocyanoethyl methacrylate plays a synergistic role, and then with siloxy acrylate, isocyanate acrylate, Ag-Fe 3 O 4 The powder is compounded and polymerized, so that the conductive acrylic pressure-sensitive adhesive has better shielding performance and adhesion, and is stably bonded to the conductive layer and the PBC board, reducing the possibility of cracking and warping.

[0125] Combining Examples 10-12 with Example 9 and Table 3, it can be seen that the folding times and peel strength of Examples 10-12 are higher than those of Example 9, and the resistance value is smaller than that of Example 9, indicating that the use of Ag-Fe with a particle size of 10-50 nm 3 O 4 Powder, particle size 80-150nmAg-Fe 3 O 4 Powder, particle size 200-300nmAg-Fe 3 O 4 The powder is compounded to play a better role, and then it is compounded and polymerized with acrylate flexible monomer, isocyanate acrylate and silicone acrylate to make the prepared conductive acrylic pressure-sensitive adhesive have better shielding performance and adhesion, and stable bonding with the conductive layer and PBC board, reducing the possibility of cracking and warping.

[0126] This specific embodiment is merely an explanation of the present application and is not a limitation of the present application. After reading this specification, those skilled in the art may make modifications to the present embodiment without any creative contribution as needed, but such modifications are protected by the patent law as long as they are within the scope of the claims of the present application.

Claims

1. An electromagnetic shielding tape, characterized in that: It comprises a conductive layer (1) and at least one shielding pressure-sensitive layer (2), each of the shielding pressure-sensitive layers (2) being connected to the conductive layer (1), a protective layer (3) being provided on a side of each of the shielding pressure-sensitive layers (2) away from the conductive layer (1), the gram weight of each of the shielding pressure-sensitive layers (2) accounting for 100-166% of the gram weight of the conductive layer (1), and the shielding pressure-sensitive layer (2) being formed by coating and curing a conductive acrylic pressure-sensitive adhesive; The conductive acrylic pressure-sensitive adhesive is composed of the following raw materials in parts by weight: Acrylate flexible monomer 2-5 parts 3-5 parts of silicone acrylate Isocyanate acrylate 1-3 parts Initiator 0.1-0.5 parts 1-3 parts Ag-Fe3O4 powder 20-30 parts of solvent; The acrylic ester flexible monomer is one or more of lauryl methacrylate, 2-ethylhexyl acrylate, and glycidyl methacrylate; The siloxy acrylate is 2-(trimethylsiloxy)ethyl methacrylate and / or 3-trimethoxysilane propyl acrylate.

2. The electromagnetic shielding tape according to claim 1, characterized in that: The isocyanate acrylate is isocyanate ethyl acrylate and / or isocyanate ethyl methacrylate.

3. The electromagnetic shielding tape according to claim 1, characterized in that: The Ag-Fe3O4 powder is composed of Ag-Fe3O4 powder with the following particle size range: Ag-Fe3O4 powder with a particle size of 10-50nm 5-8 parts Ag-Fe3O4 powder with a particle size of 80-150nm 5-14 parts 1-5 parts of Ag-Fe3O4 powder with particle size of 200-300nm.

4. The electromagnetic shielding tape according to claim 1, characterized in that: The conductive layer is a non-woven conductive fabric.

5. The electromagnetic shielding tape according to claim 4, characterized in that: The non-woven conductive layer is a nickel-copper non-woven conductive fabric.

6. A method for preparing the electromagnetic shielding tape according to any one of claims 1 to 5, characterized in that: The following steps are involved: The conductive cloth is flattened to obtain a conductive layer; a conductive acrylic pressure-sensitive adhesive is coated on at least one side of the conductive layer, and after curing, a shielding pressure-sensitive layer is formed on at least one side of the conductive layer; a protective layer is adhered to the side of each shielding pressure-sensitive layer away from the conductive layer to obtain an electromagnetic shielding tape.

7. An application of an electromagnetic shielding tape, characterized in that: The electromagnetic shielding tape obtained according to any one of claims 1 to 6 is applied to a flexible circuit board.

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