KR102433773B1 - Electromagnetic wave shielding film comprising electromagnetic wave shielding multilayer - Google Patents

Abstract

The present specification discloses an electromagnetic wave shielding film comprising an electromagnetic wave shielding layer interposed between two or more metal sheet layers between an insulating layer and a conductive adhesive layer, and including a polymer resin adhesive layer comprising metal powder between the metal sheet layers. The film has excellent electromagnetic wave shielding effect because two or more metal sheet layers are electrically connected to each other through metal powder. Excellent resistance to cracking.

Description

Electromagnetic wave shielding film comprising multiple electromagnetic wave shielding layers

The present specification discloses an electromagnetic wave shielding film including multiple electromagnetic wave shielding layers.

As components such as electronic circuits, communication antennas, and display modules are located close to each other due to the high performance, miniaturization and integration of various electronic devices such as mobile phones, notebook computers, portable terminals, organic light emitting devices, and liquid crystal displays, There is a problem that the performance of the finished product is deteriorated due to electromagnetic interference. Therefore, it is necessary to apply an electromagnetic wave shielding material that can attenuate electromagnetic wave interference generated from a printed circuit board (PCB) or a circuit board of a flexible printed circuit board (FPCB) through shielding and grounding. As the electromagnetic wave shielding material as described above, an electromagnetic wave shielding film made of an insulating layer and a metal layer having excellent electrical conductivity is used. In particular, a single layer made of copper foil is generally used to obtain a shielding effect in a high-frequency region of 10 GHz or higher. There was a problem that it was lowered.

Japanese Patent Application Laid-Open No. 1999-243292

An object to be solved by the present invention is to provide an electromagnetic wave shielding film having excellent electromagnetic wave shielding effect in a high frequency region and excellent resistance to cracking even in repeated folding.

One embodiment of the present invention is an electromagnetic wave shielding layer; an insulating layer disposed on one surface of the electromagnetic wave shielding layer; and a conductive adhesive layer disposed on the other side of the electromagnetic wave shielding layer, wherein the electromagnetic wave shielding layer comprises two or more metal sheet layers, and a polymer resin adhesive layer comprising metal powder disposed between the metal sheet layers , to provide an electromagnetic wave shielding film.

The film according to an embodiment of the present invention comprises two or more metal sheet layers between the insulating layer and the conductive adhesive layer and an electromagnetic wave shielding layer, and by including a polymer resin adhesive layer containing metal powder between the metal sheet layers, The metal sheet layers are electrically connected to each other through metal powders, so that the electromagnetic wave shielding effect is excellent. In addition, due to the flexibility of the polymer resin, it is superior in resistance to breakage or cracking during repeated folding compared to a film including a single-layer metal sheet layer.

1 illustrates a cross-sectional structure of an electromagnetic wave shielding film according to an embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described in more detail.

The embodiments of the present invention disclosed in the text are illustrated for the purpose of explanation only, and the embodiments of the present invention may be embodied in various forms and should not be construed as being limited to the embodiments described in the text. . The present invention can make various changes and can have various forms, and the embodiments are not intended to limit the present invention to a specific disclosed form, and all changes, equivalents or substitutes included in the spirit and scope of the present invention should be understood as including

The singular expression includes the plural expression unless the context clearly dictates otherwise. In the present application, terms such as "comprise" or "have" are intended to designate that a feature, number, step, operation, component, part, or combination thereof described in the specification exists, and one or more other features The possibility of the presence or addition of numbers, steps, acts, components, parts, or combinations thereof is not excluded.

One embodiment of the present invention is an electromagnetic wave shielding layer; an insulating layer disposed on one surface of the electromagnetic wave shielding layer; and a conductive adhesive layer disposed on the other side of the electromagnetic wave shielding layer, wherein the electromagnetic wave shielding layer comprises two or more metal sheet layers, and a polymer resin adhesive layer comprising metal powder disposed between the metal sheet layers An electromagnetic wave shielding film is provided.

In the present specification, the electromagnetic wave shielding layer is a layer that provides an electromagnetic wave shielding effect in the film, and the two metal sheets are laminated with a polymer resin adhesive layer containing metal powder while arranging two or more metal sheet layers instead of a single metal sheet. By doing so, the metal powder of the adhesive layer can be electrically connected to the two metal sheets to exhibit an excellent electromagnetic wave shielding effect of 80 dB or more in a high-frequency region of 10 GHz or more. In addition, due to the flexibility of the polymer resin included in the polymer resin adhesive layer, cracks or breakage do not occur even after repeated folding, resulting in excellent durability.

In an embodiment, the metal sheet layer is a thin layer made of metal, and the metal sheet is not limited to the type of metal as long as the metal sheet is a sheet made of an electrically conductive metal such as copper, nickel, or aluminum. As an embodiment, the two or more metal sheet layers may be the same type of metal sheet layer or different types of metal sheet layers. In addition, as another embodiment, the metal constituting the metal sheet layer may be copper, nickel, aluminum, or a combination thereof. As an embodiment, when the two or more metal sheet layers are a sheet layer made of copper, the electromagnetic wave shielding rate is 80 dB or higher in a high frequency region of 10 GHz or higher, but when the two or more metal sheet layers are made of aluminum or nickel, the electromagnetic wave shielding rate in a high frequency region of 10 GHz or higher is 20 to It can appear as low as 30 dB. Accordingly, from the above point of view, the metal sheet layer may be a metal sheet layer including copper, and more specifically, a copper sheet layer. The metal sheet layer may be separately manufactured like a metal foil and laminated in a film, but as long as a thin layer made of a metal having a certain thickness, such as plating or deposition, can be manufactured, the manufacturing method thereof is not limited and may be included.

In an embodiment, the total thickness of the two or more metal sheet layers may be 1 to 5 μm. Specifically, the total thickness of the metal sheet layer may be 1 μm or more, 1.5 μm or more, 2 μm or more, 2.5 μm or more, 3 μm or more, 3.5 μm or more, 4 μm or more, or 4.5 μm or more, 5 μm or less, 4.5 μm or less, 4 μm or less, 3.5 μm or less, 3 μm or less, 2.5 μm or less, 2 μm or less, or 1.5 μm or less. If the total thickness of the two or more metal sheet layers is less than 1 μm, the electromagnetic wave shielding effect is reduced, and when it exceeds 5 μm, the resistance to repeated folding is low, and cracks may occur in the metal sheet layer.

In one embodiment, the thickness of one layer of the metal sheet layer may be 0.5 to 2.5 μm. Specifically, the total thickness of the metal sheet layer may be 0.5 μm or more, 1 μm or more, 1.5 μm or more, or 2 μm or more, and may be 2.5 μm or less, 2 μm or less, or 1.5 μm or less.

As an embodiment, the metal powder included in the polymer resin adhesive layer is not limited as long as it is a metal having electromagnetic wave shielding properties, and any metal powder may be included, and may be uniformly or non-uniformly distributed in the polymer resin adhesive layer. For example, it may be a metal powder of one or more of copper, nickel and silver. As an embodiment, the metal powder may have a shape such as dendrite, flake, plate-like, spherical, amorphous, or fibrous shape, but is not limited thereto. When the metal powder is in a flat shape such as a flake or plate shape, the powder content must be high for electrical connection, and thus the resin content is relatively reduced, which may cause a problem in that the adhesive strength is lowered. In view of the above, the metal powder included in the polymer resin adhesive layer may be a dendrite or a spherical powder for stable electrical connection at a low powder content.

As an embodiment, the average particle diameter of the metal powder may be 1 to 4 μm, but is not limited thereto as long as it is within the thickness range of the polymer resin adhesive layer. Specifically, it may be 1 μm or more, 1.5 μm or more, 2 μm or more, 2.5 μm or more, 3 μm or more, or 3.5 μm or more, and 4 μm or less, 3.5 μm or less, 3 μm or less, 2.5 μm or less, 2 μm or less, or 1.5 μm or less. As an embodiment, the average particle diameter of the metal powder means an average value of the diameters of one metal powder particle. If the average particle diameter of the metal powder is equal to or greater than the thickness of the polymer resin adhesive layer, scratches may occur during coating by the metal powder, and if it is less than 1 μm, it is inefficient in terms of cost. More specifically, the metal powder may be a dendrite-type copper powder. As used herein, the term "dendrite" is a crystal structure of a metal, and when the molten metal solidifies, the metal is regularly deposited with a small nucleus as the center to form a dendritic skeleton. . As an embodiment, the metal powder may be included in an amount of 20 to 50% by weight based on the total weight of the polymer resin adhesive. When the metal powder is less than 20% by weight based on the total weight of the polymer resin adhesive, electrical connection (electrical resistance) between the metal powder or between the metal powder and the metal sheet is not efficiently made, and when it exceeds 50% by weight, the content of the polymer resin adhesive This relative decrease may cause a decrease in adhesive strength. In one embodiment, the metal powder may be 20 wt% or more, 25 wt% or more, 30 wt% or more, 35 wt% or more, 40 wt% or more, or 45 wt% or more, based on the total weight of the polymer resin adhesive, and 50 wt% or more % or less, 45 wt% or less, 40 wt% or less, 35 wt% or less, 30 wt% or less, or 25 wt% or less.

As an embodiment, the polymer resin included in the polymer resin adhesive layer may be at least one of a polyurethane resin, a polyester resin, an epoxy resin, and an acrylic resin, and as long as it is commonly used in the art, it is not limited to the specific type. All are included in the scope of the present invention.

In one embodiment, the thickness of the polymer resin adhesive layer may be 2 to 5 μm. Specifically, the thickness of the polymer resin adhesive layer may be 2 μm or more, 2.5 μm or more, 3 μm or more, 3.5 μm or more, 4 μm or more, or 4.5 μm or more, and 5 μm or less, 4.5 μm or less, 4 μm or less, 3.5 μm or less, 3 μm or less, or 2.5 μm or less. If the thickness of the polymer resin adhesive layer is less than 2 μm, the adhesion between the metal sheet layers is reduced, and if it is 5 μm, sufficient adhesive strength and flexibility can be secured.

As an embodiment, when the electromagnetic wave shielding layer includes three or more metal sheet layers, there may also be two or more polymer resin adhesive layers. For example, if the metal sheet layer is 3, the polymer resin adhesive layer is 2, if the metal sheet layer is 4, the polymer resin adhesive layer is 3, if the metal sheet layer is 5, the polymer resin adhesive layer is 4 can be a dog In view of workability and price, the number of the metal sheet layer may be two, and the polymer resin adhesive layer may be one.

As an embodiment, the ratio of the thickness of the electromagnetic wave shielding layer to the total film thickness may be 0.08 to 1. More specifically, the ratio of the thickness of the electromagnetic wave shielding layer to the total film thickness may be 0.08 or more, 0.09 or more, 0.1 or more, 0.2 or more, 0.3 or more, 0.4 or more, 0.5 or more, 0.6 or more, 0.7 or more, 0.8 or more, or 0.9 or more. and may be 1 or less, 0.9 or less, 0.8 or less, 0.7 or less, 0.6 or less, 0.5 or less, 0.4 or less, 0.3 or less, 0.2 or less, 0.1 or less, or 0.09 or less. If it is less than 0.08, the electromagnetic wave shielding rate decreases, and if it exceeds 1, cracks may occur during repeated folding.

As used herein, the term “insulating layer” refers to a layer that exerts insulating properties, thermal stability, chemical resistance, scratch resistance, etc. of the film while imparting mechanical strength to the electromagnetic wave shielding film. In one embodiment, the insulating layer may be manufactured in the form of a coating layer or a film. In one embodiment, the insulating layer is not limited as long as it provides insulating properties and heat resistance, and may include, for example, at least one of a urethane resin and an epoxy resin.

As an embodiment, the urethane resin may be used without limitation as long as it is conventional known in the art. For example, it may include a urethane resin including a carboxyl group, and in this case, the carboxyl group and the epoxy may be combined through a crosslinking reaction.

As an embodiment, the epoxy resin may be used without limitation as long as it is conventional known in the art. For example, the epoxy resin is a phenol novolac type epoxy compound, a cresol novolak type epoxy compound, a bisphenol A type epoxy compound, a bisphenol F type epoxy compound, a bisphenol S type epoxy compound, a hydrogenated bisphenol A type epoxy compound, a hydrogenated bisphenol F Epoxy compound, stilbene type epoxy compound, triazine skeleton containing epoxy compound, fluorene skeleton containing epoxy compound, linear aliphatic epoxy compound, alicyclic epoxy compound, glycidylamine type epoxy compound, triphenol methane type epoxy compound, alkyl modified Triphenol methane type epoxy compound, biphenyl type epoxy compound, dicyclopentadiene skeleton containing epoxy compound, naphthalene skeleton containing epoxy compound, aryl alkylene type epoxy compound, tetraglycidyl xylene diamine, these epoxy compounds are modified with dimer acid It may include at least one selected from the group consisting of modified epoxy compounds and dimer acid diglycidyl esters, but is not limited thereto.

In an embodiment, the insulating layer may further include a curing agent for curing the epoxy resin. As an embodiment, the curing agent is not limited as long as it is commonly known in the art, and may be appropriately selected and used according to the type of resin included therewith. For example, the curing agent may include a phenol-based curing agent, an amine-based curing agent, an isocyanate-based curing agent, an anhydride-based curing agent, an active ester-based curing agent, or a dicyanamide-based curing agent. The amount of the curing agent for the epoxy resin can be added by calculating the amount of active hydrogen to the equivalent of the epoxy resin, for example, 50 to 300 parts by weight, more specifically 100 to 200 parts by weight based on 100 parts by weight of the epoxy resin. can In addition, if necessary, a curing catalyst for accelerating the reaction of the epoxy resin and the curing agent for the epoxy resin may be selectively used, and the curing catalyst may include imidazole.

In an embodiment, the insulating layer may further include a flame retardant. In one embodiment, the flame retardant is not limited as long as it is commonly known in the art. For example, the flame retardant may include an organic phosphorus flame retardant, an organic nitrogen-containing phosphorus compound, a nitrogen compound, a silicone flame retardant, a metal hydroxide, and the like. In one embodiment, the insulating layer may include a dehydrating agent, a plasticizer, a weathering agent, an antioxidant, a heat stabilizer, a lubricant, an antistatic agent, a bleaching agent, a colorant, a surface treatment agent, a viscosity modifier, a dispersant, a phosphorus-based flame retardant, a flame retardant filler, a fluorine filler, etc. may be further included in an appropriate amount.

In an embodiment, the thickness of the insulating layer may be 2 to 10 μm. Specifically, the thickness of the insulating layer is 2 μm or more, 2.5 μm or more, 3 μm or more, 3.5 μm or more, 4 μm or more, 4.5 μm or more, 5 μm or more, 5.5 μm or more, 6 μm or more, 6.5 μm or more, 7 can be greater than or equal to μm, greater than 7.5 μm, greater than 8 μm, greater than 8.5 μm, greater than 9 μm, or greater than 9.5 μm, 10 μm or less, 9.5 μm or less, 9 μm or less, 8.5 μm or less, 8 μm or less, 7.5 μm or less, 7 μm or less, 6.5 μm or less, 6 μm or less, 5.5 μm or less, 5 μm or less, 4.5 μm or less, 4 μm or less, 3.5 μm or less, 3 μm or less, or 2.5 μm or less. If the thickness of the insulating layer is less than 2 μm, the insulation is deteriorated, and if it is more than 10 μm, the flexibility is low and handling is deteriorated.

As an embodiment, a ratio of the thickness of the insulating layer to the total film thickness may be 0.05 to 1. More specifically, the ratio of the thickness of the insulating layer to the total film thickness may be 0.05 or more, 0.1 or more, 0.2 or more, 0.3 or more, 0.4 or more, 0.5 or more, 0.6 or more, 0.7 or more, 0.8 or more, or 0.9 or more, and 1 or less. , 0.9 or less, 0.8 or less, 0.7 or less, 0.6 or less, 0.5 or less, 0.4 or less, 0.3 or less, 0.2 or less, or 0.1 or less.

In the present invention, the "conductive adhesive layer" means a layer including a conductive material to provide an electromagnetic wave shielding effect and adhesion to the conductive shielding film. For example, when the conductive shielding film is applied to a printed circuit board, the conductive adhesive layer may be attached to the printed circuit board. As an embodiment, the conductive adhesive layer may be provided in the form of a coating layer or a film layer. As an embodiment, the upper conductive adhesive layer may include, without limitation, as long as it provides electromagnetic wave shielding effect and adhesive strength, and may include, for example, at least one of a urethane resin and an epoxy resin, and a metal powder.

In one embodiment, the urethane resin and the epoxy resin may include those used for the above-described insulating layer. In one embodiment, the metal powder is not limited as long as it is a metal having an electromagnetic wave shielding property and may be included, for example, it may be a metal powder of at least one of copper, silver, nickel, aluminum, gold, tin, zinc, tungsten, and iron. can As an embodiment, the average particle diameter of the metal powder may be 1 to 4 μm, but is not limited thereto as long as it is within the thickness range of the conductive adhesive layer. Specifically, it may be 1 μm or more, 1.5 μm or more, 2 μm or more, 2.5 μm or more, 3 μm or more, or 3.5 μm or more, and 4 μm or less, 3.5 μm or less, 3 μm or less, 2.5 μm or less, 2 μm or less, or 1.5 μm or less. When the average particle diameter of the metal powder is equal to or greater than the thickness of the conductive adhesive layer, scratches may occur during coating by the metal powder, and if it is less than 1 μm, it is inefficient in terms of cost. Here, the average particle diameter of the metal powder means an average value of diameters of one metal powder particle. Specifically, the metal powder may be in the form of dendrites, flakes, plate-shaped, spherical, amorphous, fibrous, and the like, and more specifically, may be dendrite-shaped or spherical in order to provide excellent electrical conductivity compared to the content. As an embodiment, the metal powder may be included in an amount of 20 to 50% by weight based on the total weight of the conductive adhesive layer. It may be included in an amount of 20 to 50% by weight. When the amount of the metal powder is less than 20% by weight based on the total weight of the conductive adhesive layer, the electrical connection (electrical resistance) is not efficiently made, and when it is more than 50% by weight, the content of the conductive adhesive is relatively reduced, so that the adhesive force may be reduced. In one embodiment, the metal powder may be 20 wt% or more, 25 wt% or more, 30 wt% or more, 35 wt% or more, 40 wt% or more, or 45 wt% or more, based on the total weight of the conductive adhesive layer, and 50 wt% or less, 45 wt% or less, 40 wt% or less, 35 wt% or less, 30 wt% or less, or 25 wt% or less.

In one embodiment, the conductive adhesive layer is the same as the above-described insulating layer, if necessary, a curing agent for curing the epoxy resin, a flame retardant, a dehydrating agent, a plasticizer, a weathering agent, an antioxidant, a heat stabilizer, a lubricant, an antistatic agent, a bleaching agent, a colorant , a surface treatment agent, a viscosity modifier, a dispersant, a phosphorus-based flame retardant, a flame retardant filler, a fluorine filler, and the like may be further included in an appropriate amount. Repetitive description of these specific components is omitted.

In an embodiment, the thickness of the conductive adhesive layer may be 5 to 15 μm. Specifically, the thickness of the conductive adhesive layer is 5 μm or more, 5.5 μm or more, 6 μm or more, 6.5 μm or more, 7 μm or more, 7.5 μm or more, 8 μm or more, 8.5 μm or more, 9 μm or more, 9.5 μm or more, 10 can be greater than or equal to 10.5 μm, greater than 11 μm, greater than 11.5 μm, greater than 12 μm, greater than 12.5 μm, greater than 13 μm, greater than 13.5 μm, greater than 14 μm, greater than or equal to 14.5 μm, and greater than or equal to 15 μm, greater than or equal to 14.5 μm, 14 Less than or equal to μm, less than or equal to 13.5 μm, less than or equal to 13 μm, less than or equal to 12.5 μm, less than or equal to 12 μm, less than or equal to 11.5 μm, less than or equal to 11 µm, less than or equal to 10.5 µm, less than or equal to 10 µm, less than or equal to 9.5 µm, less than or equal to 9 µm, less than or equal to 8.5 µm, less than or equal to 8 µm , 7.5 μm or less, 7 μm or less, 6.5 μm or less, 6 μm or less, or 5.5 μm or less. If the thickness of the conductive adhesive layer is less than 5 μm, the adhesive strength is lowered, and when it exceeds 15 μm, there is a problem in that the resin flow of the adhesive is increased.

As an embodiment, the ratio of the thickness of the conductive adhesive layer to the total film thickness may be 0.1 to 1.5. More specifically, the ratio of the thickness of the conductive adhesive layer to the total film thickness is 0.1 or more, 0.2 or more, 0.3 or more, 0.4 or more, 0.5 or more, 0.6 or more, 0.7 or more, 0.8 or more, 0.9 or more, 1 or more, 1.1 or more, 1.2 or more. or more, 1.3 or more, or 1.4 or more, and 1.5 or less, 1.4 or less, 1.3 or less, 1.2 or less, 1.1 or less, 1 or less, 0.9 or less, 0.8 or less, 0.7 or less, 0.6 or less, 0.5 or less, 0.4 or less, 0.3 or less, or 0.2 may be below.

As an embodiment, the present invention may further include a release film layer disposed on the opposite surface of the conductive adhesive layer on which the electromagnetic wave shielding layer is disposed. The release film layer is for protecting the conductive adhesive layer from foreign substances, and can be used without limitation as long as it is peelable, for example, it may be made of a synthetic resin film, or may further include a synthetic resin coating layer on a release paper. The synthetic resin is, for example, polyester-based such as polyethylene terephthalate (PET), polybutylene terephthalate, and reethylene naphthalate, polyethylene, polypropylene, cellophane, diacetyl cellulose, triacetyl cellulose, acetyl cellulose butyrate, polychloride. Vinyl, polyvinylidene chloride, polyvinyl alcohol, ethylene-vinyl acetate copolymer, polystyrene, polycarbonate, polymethylpentene, polysulfone, polyetheretherketone, polyethersulfone, polyetherimide, polyimide, It may include a fluororesin, polyamide, acrylic resin, norbornene-based resin or cycloolefin resin, or a combination thereof. Alternatively, if necessary, a release agent may be further coated for peeling. The release agent is a release material for protection of the release paper layer, and the user may appropriately select a thickness, material, etc. to be coated in consideration of punchability and peeling force. Specifically, the release film may be a transparent PET release-coated film.

As an embodiment, the film is prepared by a manufacturing method comprising the steps of coating an insulating layer on one side of the electromagnetic wave shielding film layer on the insulating layer, and coating a conductive adhesive layer on the other side of the electromagnetic wave shielding film layer. can As another embodiment, the film is prepared by coating an insulating layer and a conductive adhesive layer on a base film, respectively; laminating the insulating layer on one surface of the electromagnetic wave shielding film layer; and laminating a conductive adhesive layer on the other side of the electromagnetic wave shielding film layer. Optionally, the method may further include laminating a release film layer on the opposite side of the conductive adhesive layer on which the electromagnetic wave shielding layer is disposed. The coating or lamination process may be applied to a method commonly used in the technical field of the present invention. For example, the insulating layer and the conductive adhesive layer may be coated by using one or more coating processes such as gravure coating, micro gravure coating, spin coating, screen printing, comma coating, and die coating. It may be formed by applying a composition corresponding to the layer to one surface of the electromagnetic wave shielding film layer and drying. As an embodiment, the coating of each layer may be performed at once or sequentially.

As an embodiment, the electromagnetic wave shielding layer uses a roll-to-roll coating method on the metal sheet layer to apply and dry the polymer resin adhesive layer composition with gravure, micro gravure, comma coater, etc. It may be manufactured by a method of laminating another metal sheet layer thereon.

The electromagnetic wave shielding film according to an embodiment of the present invention has an electromagnetic wave shielding rate of 80 dB or more, 81 dB or more, 82 dB or more, 83 dB or more, 84 dB or more, 85 dB or more, 86 dB or more at a frequency of 10 GHz. , 87 dB or more, 88 dB or more, 89 dB or more, or 90 dB or more.

The electromagnetic wave shielding film according to embodiments of the present invention exhibits an electrical resistance change of 0.1 Ω or less, 0.09 Ω or less, 0.08 Ω or less, 0.07 according to a folding test using YUASA's tabletop durability tester DMLHP-CS. Ω or less, 0.06 Ω or less, 0.05 Ω or less, 0.04 Ω or less, 0.03 Ω or less, 0.02 Ω or less, or 0.01 Ω or less.

The electromagnetic wave shielding film according to embodiments of the present invention has an adhesive strength according to JIS C 6471 8.1 test method of 700 gf/cm or more, 750 gf/cm or more, 800 gf/cm or more, 850 gf/cm or more, 900 gf /cm or more, 950 gf/cm or more, or 1,000 gf/cm or more. As an embodiment, the electromagnetic wave shielding film may have an adhesive strength of 1,200 gf/cm or less according to the JIS C 6471 8.1 test method.

The electromagnetic wave shielding film according to embodiments of the present invention may be for a printed circuit board.

Hereinafter, the present invention will be described in more detail through examples. These examples are only for illustrating the present invention, and it will be apparent to those of ordinary skill in the art that the scope of the present invention is not to be construed as being limited by these examples.

[Production Example 1]

As an embodiment of the present invention, the following electromagnetic wave shielding film was prepared.

The insulating layer was mixed with 80% by weight of urethane resin (Nanox NPE-2100), 8% by weight of epoxy resin (Nanox NH-E220), and 12% by weight of carbon black dispersion (DearS M TSI-BLACK) for film color development. An insulating layer composition coating solution was prepared, and it was prepared by coating the release-treated Matt PET (Toray; XZ31) with a thickness of 7 μm by a comma coating method.

The conductive adhesive layer was prepared by mixing 45 wt% of urethane resin (Nanox NPE-2100), 5 wt% of epoxy resin (Nanox NH-E220), and 50 wt% of copper powder (Mitsui Metal ACBY-2F) to prepare a conductive adhesive layer composition, , was prepared by coating the release-treated PET film (Yulchon Chemical; P75H) with a thickness of 10 μm by comma coating method.

For the electromagnetic wave shielding layer, two copper foils made of 100 wt% copper and a polymer resin adhesive layer composition prepared in the same composition and method as the conductive adhesive layer were prepared under the thickness conditions shown in the table below. And after applying and drying the polymer resin adhesive layer composition in a comma coating method using a Roll-to-Roll coating method on the copper foil, another copper foil was heated and laminated thereon.

Then, the insulating layer was thermally laminated on one side of the prepared electromagnetic wave shielding layer, and the conductive adhesive layer was thermally laminated on the other side of the electromagnetic wave shielding layer, and each electromagnetic wave of Examples 1-3 and Comparative Examples 1-4 was thermally laminated. A shielding film was prepared.

Copper foil thickness (μm) Adhesive thickness (μm) Example 1 One 2 Example 2 2 3 Example 3 5 5 Comparative Example 1 0.5 One Comparative Example 2 0.5 6 Comparative Example 3 6 One Comparative Example 4 6 6

[Test Example 1]

As characteristics of the electromagnetic wave shielding films of Examples 1-3 and Comparative Examples 1-4 prepared in Preparation Example 1, durability (folding test), electromagnetic wave shielding rate, and adhesive force during repeated folding were measured.

Folding test

Each electromagnetic wave shielding film is folded 1,000 times using YUASA's tabletop durability tester DMLHP-CS, and the electrical resistance value before and after folding is compared to check whether the electromagnetic wave shielding layer is damaged. When the electrical resistance is changed, it is considered that a crack has occurred in the metal sheet layer of the electromagnetic wave shielding layer.

Electromagnetic wave shielding rate measurement

85055AR03 Airline Type N measuring instrument was connected to KEYSIGHT's PNA Network Analyzer model N5225A, and the shielding rate at 10 GHz was measured for each electromagnetic wave shielding film.

Adhesion measurement

Each electromagnetic wave shielding film is bonded to 50μm of PI film (SKCKOLONPI; GF Grade) using Hot Press (IST Korea; VHP series), cut to 10mm and JIS C 6471 8.1 using UTM (Universal Testing Machine; Shimadzu). Adhesion was measured accordingly.

folding shielding rate
(dB) adhesion
(gf/cm) Judgment before (Ω) After (Ω) Example 1 0.1 0.1 80 810 pass Example 2 0.1 0.1 84 1,020 pass Example 3 0.1 0.1 90 1,140 pass Comparative Example 1 0.3 0.3 70 540 fail Comparative Example 2 0.3 0.3 70 1,170 fail Comparative Example 3 0.1 10 92 520 fail Comparative Example 4 0.1 20 92 1,150 fail

As a result, as shown in the table, in Comparative Examples 1 and 2, the thickness of the metal sheet layer was less than 1 μm, so the electromagnetic wave shielding rate did not exceed 80 dB, and Comparative Example 1 was rejected due to the low adhesive strength. In Comparative Examples 3 and 4, it was confirmed that a crack occurred due to a change in electrical resistance after folding because the metal sheet layer was thicker than 5 μm. In addition, Comparative Example 3 was rejected due to low adhesive strength as in Comparative Example 1. On the other hand, in Examples 1 to 3, which are embodiments of the present invention, there was no change in electrical resistance as a result of the folding test, and cracks did not occur even during repeated folding, and the electromagnetic wave shielding rate in the high-frequency region of 10 GHz was excellent at 80 dB. In addition, it was confirmed that it has excellent adhesion of 700 gf/cm or more.

The embodiments of the present invention described above should not be construed as limiting the technical spirit of the present invention. The protection scope of the present invention is limited only by the matters described in the claims, and those skilled in the art can improve and change the technical idea of the present invention in various forms. Accordingly, such improvements and modifications will fall within the protection scope of the present invention as long as they are apparent to those of ordinary skill in the art.

10: electromagnetic wave shielding film
120: insulating layer
110: electromagnetic wave shielding layer
130: conductive adhesive layer
110a: metal sheet layer
110b: polymer resin adhesive layer

Claims (16)

electromagnetic wave shielding layer;
an insulating layer disposed on one surface of the electromagnetic wave shielding layer; and
a conductive adhesive layer disposed on the other side of the electromagnetic wave shielding layer;
including,
The electromagnetic wave shielding layer includes two or more metal sheet layers, and a polymer resin adhesive layer including a metal powder disposed between the metal sheet layers,
The total thickness of the two or more metal sheet layers is 1 to 5 μm,
The thickness of the polymer resin adhesive layer is 2 to 5 μm,
The electromagnetic wave shielding rate at 10 GHz frequency is 80 dB or more, and the electrical resistance change according to the folding test using YUASA's DMLHP-CS is 0.1 Ω or less,
electromagnetic shielding film. The electromagnetic wave shielding film of claim 1, wherein the metal of the metal sheet layer includes copper. The electromagnetic wave shielding film of claim 1, wherein the metal powder included in the polymer resin adhesive layer is a metal powder of at least one of copper, nickel, and silver. delete delete The electromagnetic wave shielding film of claim 1, wherein the insulating layer has a thickness of 2 to 10 μm. The electromagnetic wave shielding film of claim 1, wherein the conductive adhesive layer has a thickness of 5 to 15 μm. The electromagnetic wave shielding film according to claim 1, wherein a ratio of the thickness of the electromagnetic wave shielding layer to the total film thickness is 0.08 to 1. The electromagnetic wave shielding film according to claim 1, wherein the ratio of the thickness of the conductive adhesive layer to the total film thickness is 0.1 to 1.5. The electromagnetic wave shielding film according to claim 1, wherein the ratio of the thickness of the insulating layer to the total film thickness is 0.05 to 1. The electromagnetic wave shielding film of claim 1, wherein the metal powder included in the polymer resin adhesive layer is included in an amount of 20 to 50 wt% based on the total weight of the polymer resin adhesive layer. The electromagnetic wave shielding film of claim 1, further comprising a release film layer disposed on a surface opposite to which the electromagnetic wave shielding layer is disposed in the conductive adhesive layer. delete delete The electromagnetic wave shielding film according to claim 1, wherein the adhesive strength according to JIS C 6471 8.1 test method is 700 to 1,200 gf/cm. The electromagnetic wave shielding film according to claim 1, which is for a printed circuit board.

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