CN115004875B - Electromagnetic wave shielding film - Google Patents
Electromagnetic wave shielding film Download PDFInfo
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- CN115004875B CN115004875B CN202180012297.1A CN202180012297A CN115004875B CN 115004875 B CN115004875 B CN 115004875B CN 202180012297 A CN202180012297 A CN 202180012297A CN 115004875 B CN115004875 B CN 115004875B
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- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
- H05K9/00—Screening of apparatus or components against electric or magnetic fields
- H05K9/0073—Shielding materials
- H05K9/0081—Electromagnetic shielding materials, e.g. EMI, RFI shielding
- H05K9/0086—Electromagnetic shielding materials, e.g. EMI, RFI shielding comprising a single discontinuous metallic layer on an electrically insulating supporting structure, e.g. metal grid, perforated metal foil, film, aggregated flakes, sintering
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B15/00—Layered products comprising a layer of metal
- B32B15/02—Layer formed of wires, e.g. mesh
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B15/00—Layered products comprising a layer of metal
- B32B15/04—Layered products comprising a layer of metal comprising metal as the main or only constituent of a layer, which is next to another layer of the same or of a different material
- B32B15/08—Layered products comprising a layer of metal comprising metal as the main or only constituent of a layer, which is next to another layer of the same or of a different material of synthetic resin
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B27/00—Layered products comprising a layer of synthetic resin
- B32B27/18—Layered products comprising a layer of synthetic resin characterised by the use of special additives
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B3/00—Layered products comprising a layer with external or internal discontinuities or unevennesses, or a layer of non-planar shape; Layered products comprising a layer having particular features of form
- B32B3/26—Layered products comprising a layer with external or internal discontinuities or unevennesses, or a layer of non-planar shape; Layered products comprising a layer having particular features of form characterised by a particular shape of the outline of the cross-section of a continuous layer; characterised by a layer with cavities or internal voids ; characterised by an apertured layer
- B32B3/266—Layered products comprising a layer with external or internal discontinuities or unevennesses, or a layer of non-planar shape; Layered products comprising a layer having particular features of form characterised by a particular shape of the outline of the cross-section of a continuous layer; characterised by a layer with cavities or internal voids ; characterised by an apertured layer characterised by an apertured layer, the apertures going through the whole thickness of the layer, e.g. expanded metal, perforated layer, slit layer regular cells B32B3/12
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B7/00—Layered products characterised by the relation between layers; Layered products characterised by the relative orientation of features between layers, or by the relative values of a measurable parameter between layers, i.e. products comprising layers having different physical, chemical or physicochemical properties; Layered products characterised by the interconnection of layers
- B32B7/04—Interconnection of layers
- B32B7/12—Interconnection of layers using interposed adhesives or interposed materials with bonding properties
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- C—CHEMISTRY; METALLURGY
- C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
- C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
- C09J11/00—Features of adhesives not provided for in group C09J9/00, e.g. additives
- C09J11/02—Non-macromolecular additives
- C09J11/04—Non-macromolecular additives inorganic
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- C—CHEMISTRY; METALLURGY
- C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
- C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
- C09J7/00—Adhesives in the form of films or foils
- C09J7/20—Adhesives in the form of films or foils characterised by their carriers
- C09J7/29—Laminated material
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- C—CHEMISTRY; METALLURGY
- C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
- C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
- C09J9/00—Adhesives characterised by their physical nature or the effects produced, e.g. glue sticks
- C09J9/02—Electrically-conducting adhesives
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01B—CABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES
- H01B1/00—Conductors or conductive bodies characterised by the conductive materials; Selection of materials as conductors
- H01B1/20—Conductive material dispersed in non-conductive organic material
- H01B1/22—Conductive material dispersed in non-conductive organic material the conductive material comprising metals or alloys
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01B—CABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES
- H01B5/00—Non-insulated conductors or conductive bodies characterised by their form
- H01B5/14—Non-insulated conductors or conductive bodies characterised by their form comprising conductive layers or films on insulating-supports
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- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
- H05K1/00—Printed circuits
- H05K1/02—Details
- H05K1/03—Use of materials for the substrate
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- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
- H05K9/00—Screening of apparatus or components against electric or magnetic fields
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B2307/00—Properties of the layers or laminate
- B32B2307/20—Properties of the layers or laminate having particular electrical or magnetic properties, e.g. piezoelectric
- B32B2307/212—Electromagnetic interference shielding
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B2311/00—Metals, their alloys or their compounds
- B32B2311/02—Noble metals
- B32B2311/08—Silver
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B2457/00—Electrical equipment
- B32B2457/08—PCBs, i.e. printed circuit boards
-
- C—CHEMISTRY; METALLURGY
- C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
- C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
- C09J201/00—Adhesives based on unspecified macromolecular compounds
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- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Physics & Mathematics (AREA)
- Engineering & Computer Science (AREA)
- Microelectronics & Electronic Packaging (AREA)
- Dispersion Chemistry (AREA)
- Spectroscopy & Molecular Physics (AREA)
- Inorganic Chemistry (AREA)
- Electromagnetism (AREA)
- Shielding Devices Or Components To Electric Or Magnetic Fields (AREA)
- Laminated Bodies (AREA)
- Magnetic Heads (AREA)
Abstract
The invention provides an electromagnetic wave shielding film which has excellent transparency and low connection resistance value even if a large amount of conductive particles are mixed in a conductive adhesive layer. In the electromagnetic wave shielding film of the present invention, the 1 st insulating layer, the silver nanowire layer, the 2 nd insulating layer, and the conductive adhesive layer are laminated in this order, the thickness of the 2 nd insulating layer is 50 to 500nm, the conductive adhesive layer includes a binder component and spherical or dendritic conductive particles, and the content of the conductive particles is1 to 80 mass% relative to 100 mass% of the conductive adhesive layer.
Description
Technical Field
The present invention relates to an electromagnetic wave shielding film. More particularly, the present invention relates to an electromagnetic wave shielding film for use in a printed wiring board.
Background
Printed wiring boards are widely used in electronic devices such as cellular phones, video cameras, and notebook personal computers to incorporate circuits into a mechanism. Is also used to connect the movable part and the control part of the printhead. In these electronic devices, electromagnetic wave shielding measures are necessary, and even a printed wiring board used in the device, a shielded printed wiring board in which electromagnetic wave shielding measures are implemented is used.
For the purpose of electromagnetic wave shielding measures, an electromagnetic wave shielding film (hereinafter also simply referred to as "shielding film") is used in shielding printed wiring boards. For example, a shielding film used for bonding to a printed wiring board includes a shielding layer such as a metal layer and a conductive bonding sheet provided on the surface of the shielding layer.
As a shielding film containing a conductive bonding sheet, for example, those disclosed in patent documents 1 and 2 are known. The shielding film is bonded to the surface of the printed wiring board, specifically, to the surface of a cover film provided on the surface of the printed wiring board, by the surface exposed from the conductive bonding sheet. The conductive bonding sheet is bonded to a printed wiring board by thermocompression bonding under high Wengao pressure. The shielding film disposed on the printed wiring board in this way exhibits a performance of shielding electromagnetic waves from outside the printed wiring board (shielding performance).
Prior art literature
Patent literature
Patent document 1, japanese patent application laid-open No. 2015-110769;
Patent document 2 japanese patent laid-open publication No. 2012-28334.
Disclosure of Invention
Technical problem to be solved by the invention
In recent years, a shield film is sometimes required to have a performance of easy alignment when attached to a printed wiring board. Therefore, the shielding film tends to require transparency. As a method for improving transparency, for example, a transparent conductive layer having a thin layer thickness is used as a conductive layer in a shielding film.
However, in the conventional shielding film, the conductivity increases as the amount of the conductive particles blended in the conductive adhesive layer increases, whereas in the shielding film using the transparent conductive layer, if a large amount of the conductive particles are blended in the conductive adhesive layer, there is a problem that the connection resistance value increases and the conductivity decreases.
The present invention has been made in view of the above-described problems, and an object of the present invention is to provide an electromagnetic wave shielding film which can provide excellent transparency and a low connection resistance value even when a large amount of conductive particles are mixed in a conductive adhesive layer.
Technical means for solving the technical problems
The inventors of the present invention have made intensive studies to achieve the above object and have found that an electromagnetic wave shielding film having a specific layer structure can be excellent in transparency and low in connection resistance value even when a large amount of conductive particles are blended in a conductive adhesive layer. The present invention has been completed based on this finding.
That is, the present invention provides an electromagnetic wave shielding film in which a1 st insulating layer, a silver nanowire layer, a2 nd insulating layer, and a conductive adhesive layer are laminated in this order.
The thickness of the 2 nd insulating layer is 50-500 nm,
The conductive adhesive layer includes a binder component and spherical or dendritic conductive particles,
The content of the conductive particles is 1 to 80% by mass relative to 100% by mass of the conductive adhesive layer.
Preferably, the 2 nd insulating layer and the conductive adhesive layer are directly laminated.
Preferably, the 2 nd insulating layer is directly laminated on one surface of the conductive adhesive layer and on the other surface of the conductive adhesive layer.
The content of the conductive particles is preferably 30 to 80% by mass based on 100% by mass of the conductive adhesive layer.
The electromagnetic wave shielding film preferably has a total light transmittance of 10% or more in a measurement method according to JIS K7361-1.
In addition, the present invention provides a shielding printed wiring board including the above electromagnetic wave shielding film.
Effects of the invention
The electromagnetic wave shielding film of the present invention can be made excellent in transparency and low in connection resistance value, regardless of whether a small amount of conductive particles or a large amount of conductive particles are blended in the conductive adhesive layer.
Drawings
Fig. 1 is a schematic cross-sectional view of an embodiment of an electromagnetic wave shielding film according to the present invention.
Detailed Description
[ Shielding film ]
The shielding film of the present invention has a layer structure in which a1 st insulating layer, a silver nanowire layer, a 2 nd insulating layer, and a conductive adhesive layer are laminated in this order.
An embodiment of the shielding film of the present invention will be described below. Fig. 1 is a schematic cross-sectional view of an embodiment of a shielding film of the present invention. The shielding film 1 of the present invention shown in fig. 1 includes a 1 st insulating layer 11, a silver nanowire layer 12, a 2 nd insulating layer 13, and a conductive adhesive layer 14 in this order.
(1 St insulating layer)
The 1 st insulating layer is a transparent substrate that functions as a support for the silver nanowire layer in the shielding film of the present invention. Examples of the 1 st insulating layer include a plastic substrate (particularly a plastic film) and a glass plate. The 1 st insulating layer may be a single layer, or may be a laminate of the same kind or different kinds.
Examples of the resin constituting the plastic substrate include polyolefin resins such as low density polyethylene, linear low density polyethylene, medium density polyethylene, high density polyethylene, ultra low density polyethylene, random copolymer polypropylene, block copolymer polypropylene, homo-polypropylene, polybutene, polymethylpentene, ethylene-vinyl acetate copolymer (EVA), ionomer, ethylene- (meth) acrylic acid copolymer, ethylene- (meth) acrylic acid ester (random, alternating) copolymer, ethylene-butene copolymer, ethylene-hexene copolymer, etc., polyesters such as polyurethane, polyethylene terephthalate (PET), polyethylene naphthalate, polybutylene terephthalate (PBT), polycarbonates (PC), polyimides (PI), polyetheretherketone (PEEK), polyetherimides, aromatic polyamides, wholly aromatic polyamides, polyphenylene sulfide, polysulfone (PS), polyethersulfone (PES), acrylic resins such as polymethyl methacrylate (PMMA), acrylonitrile-butadiene-styrene copolymer (ABS), fluorocarbon resins, polyvinylidene chloride (TAC), cellulose resins such as polyvinyl chloride (TAC), and the like. The resin may be used alone or in combination of two or more. Among them, polyester and cellulose resins are preferable, and polyethylene terephthalate and triacetyl cellulose are more preferable from the viewpoint of better transparency.
For the purpose of improving the close adhesion, retention, and the like with the silver nanowire layer and the like, the surface of the 1 st insulating layer (particularly the silver nanowire layer side surface) may be subjected to physical treatments such as corona discharge treatment, plasma treatment, blasting treatment, ozone exposure treatment, flame exposure treatment, high-voltage electric shock exposure treatment, ionizing radiation treatment, chemical treatments such as chromic acid treatment, and surface treatments such as easy-to-bond treatment using a coating agent (primer). The surface treatment for improving the close-bonding property is preferably applied to the entire surface of the silver nanowire layer side in the 1 st insulating layer.
The thickness of the 1 st insulating layer is not particularly limited, but is preferably 1 to 15. Mu.m, more preferably 3 to 10. Mu.m. When the thickness is 1 μm or more, the shielding film can be more sufficiently supported and the silver nanowire layer can be protected. When the thickness is 15 μm or less, the transparency and flexibility are excellent, and the economical efficiency is also advantageous. If the 1 st insulating layer has a plural-layer structure, the thickness of the 1 st insulating layer is the sum of all the layer thicknesses.
(Silver nanowire layer)
The silver nanowire layer is an element that functions as a shielding layer in the shielding film of the present invention. The silver nanowire layer may be a single layer or a laminate of the same kind or different kinds.
The thickness of the silver nanowire layer is preferably 20 to 500nm, more preferably 50 to 150nm. When the thickness is 20nm or more, high shielding performance can be maintained. When the thickness is 500nm or less, the shielding film is excellent in transparency. When the silver nanowire layer has a multi-layer structure, the thickness of the silver nanowire layer is the sum of all layer thicknesses.
(Insulating layer 2)
The 2 nd insulating layer is a transparent layer protecting the silver nanowire layer. By providing the 2 nd insulating layer between the silver nanowire layer and the conductive adhesive layer, a decrease in transparency and connection stability can be suppressed. The decrease in transparency and connection stability is presumably due to the damage of the silver nanowire layer caused by friction with the conductive particles in the conductive adhesive layer. The 2 nd insulating layer may be a single layer or a plurality of layers.
The 2 nd insulating layer preferably includes a binder component. The binder component may be a thermoplastic resin, a thermosetting resin, an active energy ray-curable compound, or the like. Examples of the thermoplastic resin, the thermosetting resin, and the active energy ray-curable compound include those which may include a binder component as the conductive adhesive layer described later. The binder component may be used alone or in combination of two or more.
The content of the binder component in the 2 nd insulating layer is not particularly limited, but is preferably 70% by mass or more, more preferably 80% by mass or more, and still more preferably 90% by mass or more, based on 100% by mass of the 2 nd insulating layer. When the content is 70 mass% or more, the flexibility is more excellent, the insertion into a small-diameter hole is excellent, and the connection stability is more excellent.
The 2 nd insulating layer may contain other components than the binder component described above within a range that does not impair the effects of the present invention. Examples of the other components include a curing agent, a curing accelerator, a plasticizer, a flame retardant, an antifoaming agent, a viscosity adjuster, an antioxidant, a diluent, an anti-settling agent, a filler, a leveling agent, a coupling agent, an ultraviolet absorber, an adhesion-promoting resin, and an anti-blocking agent. The other components may be used alone or in combination of two or more.
The thickness of the 2 nd insulating layer is 50 to 500nm, preferably 100 to 300nm. By making the thickness 50nm or more, the shielding performance and the connection stability are excellent. When the thickness is 500nm or less, the transparency and the connection stability are excellent. If the 2 nd insulating layer has a plural layer structure, the thickness of the 2 nd insulating layer is the sum of all the layer thicknesses.
From the viewpoint of protecting the silver nanowire layer, the 2 nd insulating layer is preferably directly laminated with the conductive adhesive layer, and particularly preferably directly laminated with the conductive adhesive layer on one side and directly laminated with the silver nanowire layer on the other side, respectively.
(Conductive adhesive layer)
The conductive adhesive layer has, for example, bondability for bonding the shielding film of the present invention to a printed wiring board and conductivity for electrically connecting to the silver nanowire layer. And also functions as a shielding layer that exhibits shielding performance together with the silver nanowire layer. The conductive adhesive layer may be a single layer or a plurality of layers.
The conductive adhesive layer contains a binder component and spherical or dendritic conductive particles.
The binder component may be a thermoplastic resin, a thermosetting resin, an active energy ray-curable compound, or the like. The binder component may be used alone or in combination of two or more.
Examples of the thermoplastic resin include polystyrene-based resins, vinyl acetate-based resins, polyester-based resins, polyolefin-based resins (for example, polyethylene-based resins, polypropylene-based resin compositions, and the like), polyimide-based resins, and acrylic-based resins. The thermoplastic resin may be used alone or in combination of two or more.
The thermosetting resin includes both a resin having thermosetting properties (thermosetting resin) and a resin obtained by curing the thermosetting resin. Examples of the thermosetting resin include phenol resins, epoxy resins, polyurethane resins, polyurethaneurea resins, melamine resins, alkyd resins, and the like. The thermosetting resin may be used alone or in combination of two or more.
Examples of the epoxy resin include bisphenol type epoxy resins, spiro (spirocycle) type epoxy resins, naphthalene type epoxy resins, biphenyl type epoxy resins, terpene type epoxy resins, glycidyl ether type epoxy resins, glycidyl amine type epoxy resins, and (novolac) type epoxy resins.
Examples of the bisphenol type epoxy resin include bisphenol a type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, tetrabromobisphenol a type epoxy resin, and the like. Examples of the glycidyl ether type epoxy resin include tris (glycidyl ether oxyphenyl) methane and tetrakis (glycidyl ether oxyphenyl) ethane. Examples of the glycidylamine-type epoxy resin include tetraglycidyl diaminodiphenylmethane. Examples of the (novolac) type epoxy resin include cresol (novolac) type epoxy resin, phenol (novolac) type epoxy resin, α -naphthol (novolac) type epoxy resin, brominated phenol (novolac) type epoxy resin, and the like.
The active energy ray-curable compound includes both compounds curable by irradiation with active energy rays (active energy ray-curable compounds) and compounds obtained by curing the active energy ray-curable compounds. The active energy ray-curable compound is not particularly limited, and examples thereof include polymerizable compounds having at least 2 radical-reactive groups (e.g., a (meth) acryloyl group) in the molecule. The active energy ray-curable compound may be used alone or in combination of two or more.
Among them, the binder component is preferably a thermosetting resin. In this case, after the shielding film of the present invention is disposed on a printed wiring board for bonding to the printed wiring board, the adhesive component can be cured by pressurizing and heating, and the bonding property with the printed wiring board is good.
When the binder component includes a thermosetting resin, a curing agent for promoting a thermosetting reaction may be included as a component constituting the binder component. The curing agent may be appropriately selected according to the type of the thermosetting resin. The curing agent may be used alone or in combination of two or more.
The content of the binder component in the conductive adhesive layer is not particularly limited, but is preferably 20 to 99 mass%, more preferably 30 to 80 mass%, and even more preferably 40 to 70 mass% with respect to 100 mass% of the total amount of the conductive adhesive layer. When the content is 20 mass% or more, the adhesion to a printed wiring board is more excellent. When the content is 99 mass% or less, the conductive particles can be sufficiently contained.
The conductive particles may be spherical conductive particles and/or dendritic conductive particles. By using the spherical or dendritic conductive particles, the transparency and the connection stability can be improved even when the particles are compounded in a large amount. Among these, the conductive particles are preferably dendritic conductive particles from the viewpoint of better connection stability. In addition, from the viewpoint of excellent transparency of the shielding film, the conductive particles are preferably spherical conductive particles.
Examples of the conductive particles include metal particles, metal-coated resin particles, and carbon-based fillers. The conductive particles may be used alone or in combination of two or more.
Examples of the metal constituting the coating portion of the metal particles and the metal-coated resin particles include gold, silver, copper, nickel, zinc, and the like. The metal may be used alone or in combination of two or more.
Specifically, examples of the metal particles include copper particles, silver particles, nickel particles, silver-coated copper particles, gold-coated copper particles, silver-coated nickel particles, jin Baonie particles, and silver-coated gold particles. Examples of the silver-coated gold particles include silver-coated copper alloy particles in which copper-containing alloy particles (for example, copper alloy particles composed of an alloy of copper, nickel, and zinc) are coated with silver. The metal particles can be produced by electrolytic method, atomizing method, reduction method, or the like.
Among them, the metal particles are preferably silver particles, silver-coated copper particles, or silver-coated copper alloy particles. Silver-coated copper particles and silver-coated copper alloy particles are particularly preferable from the viewpoints of excellent conductivity, suppression of oxidation and coagulation of metal particles, and reduction of cost of metal particles.
The median diameter (D50) of the conductive particles is not particularly limited, but is preferably 5 to 15. Mu.m, more preferably 5 to 10. Mu.m. The median diameter is the median diameter of all spherical conductive particles and/or dendritic conductive particles in the conductive adhesive layer, and means the particle diameter at 50% of the cumulative value in the particle size distribution obtained by the laser diffraction seed scattering method. By making the median diameter within the above range, the connection stability is more excellent in the present invention using conductive particles. The median diameter can be measured by, for example, a laser diffraction particle size analyzer (trade name "SALD-2200", manufactured by Shimadzu corporation).
The content of the conductive particles in the conductive adhesive layer is 1 to 80% by mass, preferably 20 to 70% by mass, and more preferably 30 to 60% by mass, based on 100% by mass of the conductive adhesive layer. In the shielding film of the present invention, the conductive adhesive layer has a low connection resistance value and excellent connection stability, regardless of whether it contains a small amount of the conductive particles of the order of 1 mass% or contains a large amount of the conductive particles of the order of up to 80 mass%.
The conductive adhesive layer may contain other components than the above components within a range that does not impair the effects of the present invention. The other components include components contained in a known or commonly used adhesive layer. Examples of the other components include curing accelerators, plasticizers, flame retardants, antifoaming agents, viscosity modifiers, antioxidants, diluents, anti-settling agents, fillers, leveling agents, coupling agents, ultraviolet absorbers, tackifying resins, and antiblocking agents. The other components may be used alone or in combination of two or more. The content of the conductive particles other than the spherical conductive particles and the dendritic conductive particles is, for example, less than 10 parts by mass, preferably less than 5 parts by mass, and more preferably less than 1 part by mass per 100 parts by mass of the spherical conductive particles and/or the dendritic conductive particles.
The thickness of the conductive adhesive layer is not particularly limited, but is preferably 3 to 20. Mu.m, more preferably 5 to 15. Mu.m. When the thickness is 3 μm or more, the shielding performance is more excellent. When the thickness is 20 μm or less, the surface of the conductive particles tends to be closer to or exposed from the surface, and the connection stability is more excellent.
The ratio of the thickness of the conductive adhesive layer to the D50 of the conductive particles [ adhesive layer thickness/D50 ] is not particularly limited, but is preferably 0.2 to 1.5, more preferably 0.5 to 1.0. When the ratio is 0.2 or more, the adhesion to an object to be bonded such as a printed wiring board is more excellent. When the ratio is 1.5 or less, the amount of conductive particles exposed from the surface of the conductive adhesive layer is large, and the connection stability is more excellent.
The shielding film of the present invention may contain a separator (release film) on the conductive adhesive layer side. The separator is laminated so as to be peelable from the shielding film of the present invention. The separator is a component that covers and protects the conductive adhesive layer, and is peeled off when the shielding film of the present invention is used.
Examples of the separator include polyethylene terephthalate (PET) film, polyethylene film, polypropylene film, plastic film coated with a release agent such as a fluorine-based release agent or a long-chain alkyl acrylate-based release agent on the surface, paper, and the like.
The thickness of the separator is preferably 10 to 200. Mu.m, more preferably 15 to 150. Mu.m. When the thickness is 10 μm or more, the protective performance is more excellent. When the thickness is 200 μm or less, the separator is easily peeled off when used.
The shielding film of the present invention may contain other layers than the 1 st insulating layer, the silver nanowire layer, the 2 nd insulating layer, and the conductive adhesive layer. Examples of the other layer include an insulating layer, an antireflection layer, an antiglare layer, an antifouling layer, a hard coat layer, an ultraviolet absorbing layer, and an anti-newton ring layer.
The shielding film of the present invention is excellent in transparency. The total light transmittance of the shielding film of the present invention in the measurement method according to JIS K7361-1 is preferably 10% or more, more preferably 20% or more, still more preferably 50% or more, and particularly preferably 65% or more. The total light transmittance can be measured using a known spectrophotometer. The total light transmittance was measured for a laminate having the 1 st insulating layer and the conductive adhesive layer as both end layers.
The haze value of the shielding film of the present invention in the measurement method according to JIS K7361-1 is preferably 95% or less, more preferably 92% or less, and still more preferably 90% or less. The haze value can be measured using a known spectrophotometer. The haze value was measured on a laminate having the 1 st insulating layer and the conductive adhesive layer as both end layers.
The shielding film of the present invention is preferably used for a printed wiring board, particularly preferably for a flexible printed wiring board (FPC). The shielding film of the present invention can have a low connection resistance value regardless of whether a small amount of conductive particles or a large amount of conductive particles are mixed in the conductive adhesive layer. And has excellent transparency and easy alignment on the printed wiring board. Therefore, the shielding film of the present invention can be suitably used as an electromagnetic wave shielding film for flexible printed wiring boards.
(Method for producing electromagnetic wave-shielding film)
A method for manufacturing the shielding film of the present invention will be described.
In the production process of the shielding film 1 of the present invention shown in fig. 1, first, the silver nanowire layer 12 is formed on the 1 st insulating layer 11. The silver nanowire layer 12 can be formed by laminating the silver nanowire layer 12 on the surface of the 1 st insulating layer 11.
Next, the resin composition for forming the 2 nd insulating layer 13 can be applied (coated) on the surface of the silver nanowire layer 12 to be formed by removing the solvent and/or partially curing, if necessary.
The resin composition includes, for example, a solvent (solvent) in addition to the components contained in the 2 nd insulating layer. Examples of the solvent include toluene, acetone, methyl ethyl ketone, methanol, ethanol, propanol, ethyl acetate, propyl acetate, butyl acetate, and dimethylformamide. The solid content concentration of the resin composition is appropriately set in accordance with the thickness of the 2 nd insulating layer to be formed, and the like.
The coating of the above resin composition may be carried out by a known coating method. Examples of the coating machine include gravure roll coater, reverse roll coater, oil-feeding roll coater, dip roll coater for lip coater, bar coater, knife coater, spray coater, comma coater, direct coater, and slit coater.
Next, the adhesive composition for forming the conductive adhesive layer 14 can be applied (coated) on the surface of the formed 2 nd insulating layer, and if necessary, the composition can be formed by removing the solvent and/or partially curing the composition.
The adhesive composition includes, for example, a solvent (solvent) in addition to the components contained in the conductive adhesive layer. The solvent may be exemplified as a solvent which can be included in the resin composition. The solid content concentration of the adhesive composition is appropriately set according to the thickness of the conductive adhesive layer to be formed, and the like.
The adhesive composition may be applied by a known application method. For example, an example of a coater used for coating the resin composition is given.
In the above-described production method, the method of producing each layer by sequentially forming the layers (direct coating method) is described, but the method is not limited to the above-described method, and for example, the method of laminating each layer formed individually on a temporary substrate such as a release film or a substrate and sequentially bonding the layers (lamination method) may be used.
The shielding film of the present invention can be used to produce a printed wiring board. For example, a shield printed wiring board having the shield film of the present invention bonded to a printed wiring board can be obtained by bonding the conductive adhesive layer of the shield film of the present invention to a printed wiring board (for example, a cover film). In the above-described shielded printed wiring board, the conductive adhesive layer may be thermally cured.
Examples
The present invention will be described in further detail with reference to examples, but the present invention is not limited to these examples. The content ratio of the conductive particles in the table indicates the ratio in the conductive adhesive layer.
Comparative example 1
Silver nanowire layers (wire diameter 30nm, wire length 20 μm, thickness about 70 nm) were laminated on the surface of a PET film (thickness 6 μm) and laminated. Then, an adhesive composition obtained by mixing an epoxy resin solution and conductive particles a was applied to the surface of the silver nanowire layer using a wire bar, and heated at 120 ℃ for 1 minute, thereby forming a conductive adhesive layer (thickness 5 μm). The shielding film of comparative example 1 was produced as above. The mixing amounts of the epoxy resin solution and the conductive particles a were set to an amount such that the ratio of the epoxy resin in the conductive adhesive layer was 70 mass% and the ratio of the conductive particles a was 30 mass%.
Comparative examples 2 and 3
Each shielding film was produced in the same manner as in comparative example 1 except that the types and the content ratios of the conductive particles were changed as shown in table 1.
Example 1
Silver nanowire layers (wire diameter 30nm, wire length 20 μm, thickness about 70 nm) were laminated on the surface of a PET film (thickness 6 μm) and laminated. Next, a polyester resin composition was coated on the surface of the silver nanowire layer using a wire rod, and heated at 100 ℃ for 1 minute, thereby forming a resin layer (thickness 50 nm). Then, an adhesive composition obtained by mixing an epoxy resin solution and conductive particles a was applied to the surface of the resin layer by using a wire bar, and heated at 120 ℃ for 1 minute, thereby forming a conductive adhesive layer (thickness 5 μm). The shielding film of example 1 was produced as above. The mixing amounts of the epoxy resin solution and the conductive particles a were set to an amount such that the ratio of the epoxy resin in the conductive adhesive layer was 70 mass% and the ratio of the conductive particles a was 30 mass%.
Examples 2,3 and comparative example 4
Each shielding film was produced in the same manner as in example 1 except that the thickness of the resin layer was changed to that shown in table 1.
Example 4
A shielding film was produced in the same manner as in example 1 except that the content ratio of the conductive particles was changed to those shown in table 1.
Examples 5,6 and comparative example 5
Each shielding film was produced in the same manner as in example 4 except that the thickness of the resin layer was changed to that shown in table 1.
Example 7
A shielding film was produced in the same manner as in example 1 except that the types of the conductive particles were changed as shown in table 1.
Examples 8,9 and comparative example 6
Each shielding film was produced in the same manner as in example 7 except that the thickness of the resin layer was changed to that shown in table 1.
(Evaluation)
The shielding films obtained in examples and comparative examples were evaluated as follows. The evaluation results are shown in the table. Only a PET film (thickness 6 μm) was used as the evaluation object of reference example 1. The term "OL" in the table is also expressed as a value exceeding the measurement limit 100deg.C due to overload.
(1) Connection resistance value
A printed wiring substrate was prepared in which 2 copper foil patterns (4 mm wide, 1mm pitch) having an approximate ground pattern were formed on a base member made of a polyimide film, and a cover film (insulating film) made of an insulating adhesive layer and a polyimide film was formed thereon. A gold plating layer is provided as a surface layer on the surface of the copper foil pattern. And a circular opening part of the analog ground connection part with the diameter of 0.8mm is formed on the covering film. The shielding films and the printed wiring substrates produced in each example and comparative example were bonded using a press at a temperature of 170 ℃ for 30 minutes and a pressure of 2 to 3 MPa. After the shielding film was bonded, the resistance value between 2 copper foil patterns was measured by a resistance meter, and the connectivity between the copper foil patterns and the conductive bonding sheet was evaluated as a connection resistance value.
(2) Total light transmittance
The shielding films obtained in examples and comparative examples were measured by irradiating a surface of a PET film with measuring light on the side of an integrating sphere in accordance with JIS K7361-1 using a haze measuring instrument (trade name "NDH4000", manufactured by Nippon Denshoku Kogyo Co., ltd.).
TABLE 1
When a silver nanowire layer is used as the transparent conductive layer, the shielding film of the present invention can have high total light transmittance, excellent transparency, low connection resistance value, and excellent connection stability even when a large amount of conductive particles are blended up to 30 to 50 mass% (examples 1 to 9). In addition, when spherical conductive particles (examples 1 to 6) are used, the total light transmittance tends to be high and the transparency tends to be excellent, compared to the case where dendritic conductive particles (examples 7 to 9) are used. On the other hand, when using dendritic conductive particles (examples 7 to 9), the connection resistance value tends to be low and the connection stability tends to be excellent, compared to the case of using spherical conductive particles (examples 1 to 6). In the case where no resin layer is present between the silver nanowire layer and the conductive adhesive layer (comparative examples 1 to 3), the connection resistance value is high in the case where a large amount of 30 mass% or more of the conductive particles are used in the same proportion (examples 1 to 9).
Numbering represents
1. Shielding film
11. 1 St insulating layer
12. Silver nanowire layer
13. 2 Nd insulating layer
14. Conductive adhesive layer
Claims (7)
1. An electromagnetic wave shielding film, characterized in that:
A1 st insulating layer, a silver nanowire layer, a2 nd insulating layer, and a conductive adhesive layer are laminated in this order;
The 1 st insulating layer is a transparent substrate;
The 2 nd insulating layer is a transparent layer and has the thickness of 50-300 nm;
the conductive adhesive layer includes a binder component and spherical or dendritic conductive particles;
The content of the conductive particles is 20 to 70% by mass relative to 100% by mass of the conductive adhesive layer.
2. The electromagnetic wave shielding film according to claim 1, wherein:
the 2 nd insulating layer and the conductive adhesive layer are directly laminated.
3. The electromagnetic wave shielding film according to claim 1, wherein:
the 2 nd insulating layer is directly laminated with the conductive adhesive layer on one side and the silver nanowire layer on the other side.
4. The electromagnetic wave shielding film according to claim 1, wherein:
the thickness of the 2 nd insulating layer is 50-200 nm.
5. The electromagnetic wave shielding film according to claim 1, wherein:
The content of the conductive particles is 30 to 50% by mass relative to 100% by mass of the conductive adhesive layer.
6. The electromagnetic wave shielding film according to any one of claims 1 to 5, wherein:
The total light transmittance in the measurement method according to JIS K7361-1 is 10% or more.
7. A shielded printed wiring board, characterized in that:
the shielding printed wiring board comprises the electromagnetic wave shielding film according to any one of claims 1 to 6.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2020-030262 | 2020-02-26 | ||
| JP2020030262 | 2020-02-26 | ||
| PCT/JP2021/007245 WO2021172486A1 (en) | 2020-02-26 | 2021-02-26 | Electromagnetic wave shielding film |
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| CN115004875A CN115004875A (en) | 2022-09-02 |
| CN115004875B true CN115004875B (en) | 2025-03-28 |
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| JP (1) | JP7027618B2 (en) |
| KR (1) | KR102724516B1 (en) |
| CN (1) | CN115004875B (en) |
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| CN115103582B (en) * | 2022-05-19 | 2025-07-01 | 贵州大学 | Electromagnetic interference shielding nanocomposite film with asymmetric alternating multilayer structure and preparation method thereof |
| CN115696898B (en) * | 2022-11-08 | 2025-08-19 | 广州方邦电子股份有限公司 | Electromagnetic shielding film and circuit board |
| KR102837454B1 (en) | 2024-11-21 | 2025-07-24 | 한국전자기술연구원 | Electromagnetic shielding film having heat dissipation properties and method for manufacturing the same |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103120042A (en) * | 2010-06-23 | 2013-05-22 | 印可得株式会社 | Method for manufacturing electromagnetic shielding film and electromagnetic shielding film manufactured thereby |
| CN109575827A (en) * | 2018-12-26 | 2019-04-05 | 苏州诺菲纳米科技有限公司 | The preparation method and display device of electromagnetic shielding film, electromagnetic shielding film |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| JP2006035773A (en) * | 2004-07-29 | 2006-02-09 | Takiron Co Ltd | Self-adhesive conductive molding |
| JP5672201B2 (en) | 2011-09-07 | 2015-02-18 | デクセリアルズ株式会社 | Anisotropic conductive film and method for manufacturing connection structure |
| SG10201706567VA (en) * | 2013-02-15 | 2017-09-28 | Cam Holding Corp | Methods to incorporate silver nanowire-based transparent conductors in electronic devices |
| WO2015068611A1 (en) | 2013-11-07 | 2015-05-14 | 東洋インキＳｃホールディングス株式会社 | Electroconductive adhesive, electroconductive adhesive sheet, wiring device, and method for manufacturing wiring device |
| CN104010435A (en) * | 2014-06-12 | 2014-08-27 | 苏州城邦达力材料科技有限公司 | Covering film with electromagnetic shielding function and manufacturing technology of covering film with electromagnetic shielding function |
| KR20170024241A (en) * | 2015-08-25 | 2017-03-07 | 주식회사 에스지 | Automotive Head Light projection lens manufacturing apparatus |
| CN107517580A (en) * | 2016-06-15 | 2017-12-26 | 上海蓝沛新材料科技股份有限公司 | A kind of compound FCCL materials and its manufacture method with electro-magnetic screen function |
| CN108668517A (en) * | 2017-04-01 | 2018-10-16 | 中国科学院化学研究所 | Electromagnetic shielding film and preparation method thereof |
| JP2019125529A (en) * | 2018-01-18 | 2019-07-25 | タツタ電線株式会社 | Conductive adhesive film and electromagnetic wave shield film including the same |
| CN208500827U (en) * | 2018-05-09 | 2019-02-15 | 东莞市古川胶带有限公司 | A non-substrate adhesive tape with electromagnetic shielding function |
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2020
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- 2021-02-26 CN CN202180012297.1A patent/CN115004875B/en active Active
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103120042A (en) * | 2010-06-23 | 2013-05-22 | 印可得株式会社 | Method for manufacturing electromagnetic shielding film and electromagnetic shielding film manufactured thereby |
| CN109575827A (en) * | 2018-12-26 | 2019-04-05 | 苏州诺菲纳米科技有限公司 | The preparation method and display device of electromagnetic shielding film, electromagnetic shielding film |
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| KR20220147066A (en) | 2022-11-02 |
| JPWO2021172486A1 (en) | 2021-09-02 |
| CN115004875A (en) | 2022-09-02 |
| TWI842957B (en) | 2024-05-21 |
| WO2021172486A1 (en) | 2021-09-02 |
| JP7027618B2 (en) | 2022-03-01 |
| TW202132514A (en) | 2021-09-01 |
| KR102724516B1 (en) | 2024-11-01 |
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