CN114015375A - Conductive adhesive sheet and portable electronic device - Google Patents
Conductive adhesive sheet and portable electronic device Download PDFInfo
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- CN114015375A CN114015375A CN202111478724.3A CN202111478724A CN114015375A CN 114015375 A CN114015375 A CN 114015375A CN 202111478724 A CN202111478724 A CN 202111478724A CN 114015375 A CN114015375 A CN 114015375A
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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
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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
- C09J7/28—Metal sheet
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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
- C09J133/00—Adhesives based on homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by only one carboxyl radical, or of salts, anhydrides, esters, amides, imides, or nitriles thereof; Adhesives based on derivatives of such polymers
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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
- C09J7/30—Adhesives in the form of films or foils characterised by the adhesive composition
-
- 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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- 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
- C09J2301/00—Additional features of adhesives in the form of films or foils
- C09J2301/30—Additional features of adhesives in the form of films or foils characterized by the chemical, physicochemical or physical properties of the adhesive or the carrier
- C09J2301/314—Additional features of adhesives in the form of films or foils characterized by the chemical, physicochemical or physical properties of the adhesive or the carrier the adhesive layer and/or the carrier being conductive
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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
- C09J2400/00—Presence of inorganic and organic materials
- C09J2400/10—Presence of inorganic materials
- C09J2400/16—Metal
- C09J2400/163—Metal in the substrate
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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
- C09J2433/00—Presence of (meth)acrylic polymer
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- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Inorganic Chemistry (AREA)
- Adhesives Or Adhesive Processes (AREA)
- Adhesive Tapes (AREA)
- Conductive Materials (AREA)
- Non-Insulated Conductors (AREA)
- Shielding Devices Or Components To Electric Or Magnetic Fields (AREA)
Abstract
The invention provides a conductive adhesive sheet and a portable electronic device. The conductive adhesive sheet has a conductive base material and 1 or more than 2 conductive adhesive layers, and has a total thickness of 50 [ mu ] m or less, wherein each layer of the conductive adhesive layer contains 0.01-10% by mass of at least 1 type of conductive particles, the thickness of each layer of the conductive adhesive layer is 1 [ mu ] m-12 [ mu ] m, and the particle diameter d50 of the conductive particles is 12 [ mu ] m-30 [ mu ] m.
Description
The application is a divisional application of a Chinese patent application with the application date of 2018, 5 and 28 months, the application number of 201810523726.1 and the name of conductive adhesive sheet.
Technical Field
The present invention relates to a conductive adhesive sheet having a conductive substrate and a conductive adhesive layer containing conductive particles.
Background
The conductive adhesive sheet is used for shielding unnecessary leakage electromagnetic waves radiated from electric and electronic devices, etc. due to its ease of handling, shielding harmful spatial electromagnetic waves generated from the electric and electronic devices, and grounding for preventing static electricity. In recent years, with the miniaturization and thinning of the above-mentioned electric and electronic devices, the conductive adhesive sheet used for the devices is also required to be thin.
As a thin conductive adhesive sheet having suitable conductivity and adhesiveness, an adhesive sheet having an adhesive layer formed of a conductive adhesive in which a conductive filler is dispersed in an adhesive substance on a conductive substrate is known (see patent documents 1 and 2).
However, with the recent further miniaturization and thinning of electric and electronic devices, the conductive adhesive sheet is also required to be further thinned. Further, there is a problem that the adhesiveness of the conductive adhesive sheet is lowered with time, and the conductivity is lowered. However, a conductive adhesive sheet having excellent conductivity, stability with time, and adhesiveness and being thin has not yet been found.
Documents of the prior art
Patent document
Patent document 1: japanese patent laid-open publication No. 2004-263030
Patent document 2: japanese laid-open patent publication No. 2009-79127
Disclosure of Invention
Problems to be solved by the invention
The present invention addresses the problem of providing a conductive adhesive sheet that has good adhesion and conductivity even when it is thin, and that has conductivity that is less likely to decrease over time.
Means for solving the problems
The present inventors have found that the above problems can be solved by combining the total thickness of the adhesive sheet, the content of the conductive particles in the conductive adhesive layer, and the thickness of the conductive adhesive layer within specific ranges.
That is, the present invention relates to a conductive adhesive sheet having a conductive base material and 1 or 2 or more conductive adhesive layers, and having a total thickness of 50 μm or less, wherein each layer of the conductive adhesive layer contains 0.01 to 10 mass% of at least 1 type of conductive particles, and each layer of the conductive adhesive layer has a thickness of 1 to 12 μm.
ADVANTAGEOUS EFFECTS OF INVENTION
The conductive adhesive sheet of the present invention has excellent adhesiveness to an adherend and conductivity although it is extremely thin, and therefore has conductivity stability over time, and is useful for applications for shielding electromagnetic waves used in electric and electronic devices, applications for shielding harmful spatial electromagnetic waves generated in electric and electronic devices, and applications for grounding fixation for preventing static electricity. In particular, the present invention can be suitably applied to a portable electronic device in which a reduction in thickness is advanced and a volume in a case is strictly limited.
Drawings
Fig. 1 shows a preferred example of the conductive adhesive sheet of the present invention.
Fig. 2 shows a preferred example of the conductive adhesive sheet of the present invention.
FIG. 3 is an electron micrograph of beaded conductive particles suitable for use in the conductive adhesive sheet of the present invention.
Description of the symbols
1 conductive base material
2 conductive adhesive layer
Detailed Description
The conductive adhesive sheet of the present invention has a conductive base material and 1 or 2 or more conductive adhesive layers, and has a total thickness of 50 μm or less, wherein each layer of the conductive adhesive layer contains 0.01 to 10 mass% of at least 1 type of conductive particles, and each layer of the conductive adhesive layer has a thickness of 1 to 12 μm.
The conductive adhesive sheet of the present invention will be described in further detail below based on its constituent elements. The term "sheet" in the present invention means a form in which a thin adhesive layer formed using at least one layer of a conductive adhesive is provided on a conductive substrate or a release sheet, and includes all product forms such as a single sheet, a roll, a sheet, and a tape (tape).
(conductive adhesive layer)
The conductive adhesive sheet of the present invention has 1 or 2 or more layers of conductive adhesive layer. The conductive adhesive layer contains specific conductive particles and an adhesive component. The thickness of each layer of the conductive adhesive layer is 1 to 12 μm, preferably 2.5 to 10 μm, and preferably 4 to 8 μm. The conductive adhesive layer can achieve both excellent conductivity and excellent adhesiveness even when it is thin.
The conductive thin adhesive sheet of the present invention can achieve both excellent conductivity, excellent adhesiveness, and conductivity stability with time even when it is very thin as described above.
The conductive adhesive layer can be formed by using an adhesive composition containing the conductive particles and an adhesive component.
(conductive particles)
The conductive adhesive layer contains at least 1 kind of conductive particles. As the conductive particles, those having a particle diameter d50 in the range of 10 to 30 μm are used. Thus, a conductive thin adhesive sheet having excellent conductivity, adhesiveness, and stability with time of conductivity can be obtained.
The particle diameter d50 of the conductive particles is preferably in the range of 12 to 30 μm, more preferably 10 to 26 μm.
The particle diameter d50 is a 50% integrated value in the particle size distribution, and is a value measured by a laser analysis-scattering method. The measuring apparatus includes a Microtrac MT3000II manufactured by Nikkiso K.K., a laser diffraction particle size distribution measuring apparatus SALD-3000 manufactured by Shimadzu corporation, and the like.
Examples of the method for adjusting the particle diameter d50 to the above-mentioned range include a method of pulverizing conductive particles by a jet mill, and a sieving method using a sieve or the like.
The particle diameter d50 of the conductive particles is preferably 100% to 500%, preferably 150% to 470%, relative to the thickness of the conductive adhesive agent layer containing the particles, and more preferably 200% to 450% in terms of satisfying further excellent conductivity, adhesiveness, and stability with time of conductivity.
As the conductive particles, metal powder particles such as gold, silver, copper, nickel, and aluminum, conductive resin particles such as carbon and graphite, particles having a metal coating on the surface of the resin particles, solid glass beads, and hollow glass beads, and the like can be used. Among them, as the conductive particles, nickel powder particles, copper powder particles, silver powder particles are more preferably used in view of achieving both further excellent conductivity and adhesiveness, and particularly, surface needle-shaped nickel particles produced by a carbonyl method and having a plurality of needle-shaped particle surfaces are preferably used; spherical particles obtained by smoothing (pulverizing) the surface acicular particles; copper powder, silver powder and the like produced by an ultrahigh pressure rotational flow water atomization method.
The shape of the conductive particles may be spherical, nail-like, flake-like, or bead-like in which a plurality of conductive particles are connected to each other by forming a bond therebetween as shown in fig. 3, and among them, bead-like is preferable from the viewpoint of satisfying excellent conductivity, adhesiveness, and stability with time of conductivity.
The conductive particles are contained in an amount of 0.01 to 10% by mass, more preferably 0.1 to 8% by mass, based on the total mass of the conductive adhesive layer containing the particles, and particularly preferably 0.5 to 5% by mass, in order to obtain a conductive thin adhesive sheet having further excellent conductivity, adhesiveness, and stability with time of conductivity.
(adhesive component)
As the adhesive composition used for forming the conductive adhesive layer, a composition containing the conductive particles and an adhesive component can be used.
As the adhesive composition, for example, a composition containing conductive particles such as a (meth) acrylic adhesive, a urethane adhesive composition, a synthetic rubber adhesive composition, a natural rubber adhesive composition, or a silicone adhesive composition can be used, and in order to form a conductive adhesive layer having excellent weather resistance and heat resistance, an acrylic adhesive composition containing an acrylic polymer as a base polymer and, if necessary, additives such as a tackifier and a crosslinking agent is preferably used.
As the acrylic polymer, for example, an acrylic polymer obtained by polymerizing a monomer component containing a (meth) acrylate monomer having an alkyl group having 1 to 14 carbon atoms can be suitably used.
Examples of the (meth) acrylate having an alkyl group having 1 to 14 carbon atoms include 1 or a combination of 2 or more of methyl (meth) acrylate, ethyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, t-butyl (meth) acrylate, n-hexyl (meth) acrylate, n-octyl (meth) acrylate, isooctyl (meth) acrylate, isononyl (meth) acrylate, cyclohexyl (meth) acrylate, and 2-ethylhexyl (meth) acrylate.
Among them, the (meth) acrylate having an alkyl group having 1 to 14 carbon atoms is preferably a (meth) acrylate having an alkyl group having 4 to 12 carbon atoms, more preferably a (meth) acrylate having an alkyl group having a linear or branched structure having 4 to 9 carbon atoms, and further preferably n-butyl acrylate or 2-ethylhexyl acrylate alone or in combination.
The content of the (meth) acrylate having an alkyl group having 1 to 14 carbon atoms is preferably 80 to 98.5% by mass, more preferably 90 to 98.5% by mass, based on the total amount of the monomer components used for producing the acrylic polymer.
As the monomer component that can be used in the production of the acrylic polymer, it is preferable to use a highly polar vinyl monomer as necessary in addition to the above components.
The highly polar vinyl monomer may be used alone or in combination of two or more kinds of a vinyl monomer having a carboxyl group, a vinyl monomer having a hydroxyl group, a vinyl monomer having an amide group, and the like. Among these, the use of a vinyl monomer having a carboxyl group as the highly polar vinyl monomer is preferable because the adhesiveness of the conductive adhesive layer can be easily adjusted to an appropriate range.
As the vinyl monomer having a carboxyl group, for example, acrylic acid, methacrylic acid, itaconic acid, maleic acid, (meth) acrylic acid dimer, crotonic acid, ethylene oxide-modified succinic acid acrylate, and the like can be used, and among them, acrylic acid is preferably used.
When a vinyl monomer having a carboxyl group is used, the content thereof is preferably 0.2 to 15% by mass, more preferably 0.4 to 10% by mass, and further preferably 0.5 to 6% by mass based on the total amount of the monomer components used for producing the acrylic polymer, since the adhesiveness of the adhesive can be easily adjusted to an appropriate range, it is more preferable.
Examples of the vinyl monomer having a hydroxyl group include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, and 6-hydroxyhexyl (meth) acrylate.
Examples of the vinyl monomer having an amide group include N-vinylpyrrolidone, N-vinylcaprolactam, acryloylmorpholine, acrylamide, and N, N-dimethylacrylamide.
Examples of the other highly polar vinyl monomer include sulfonic acid group-containing monomers such as vinyl acetate, ethylene oxide-modified succinic acid acrylate and 2-acrylamido-2-methylpropanesulfonic acid, and terminal alkoxy-modified (meth) acrylates such as 2-methoxyethyl (meth) acrylate and 2-phenoxyethyl (meth) acrylate.
The content of the highly polar vinyl monomer is preferably 0.2 to 15% by mass, more preferably 0.4 to 10% by mass, and even more preferably 0.5 to 6% by mass, based on the total amount of the monomer components used for producing the acrylic polymer, because the adhesiveness of the adhesive can be easily adjusted to an appropriate range.
The acrylic polymer can be produced by polymerizing the monomer component by a known method such as solution polymerization, bulk polymerization, suspension polymerization, or emulsion polymerization. Among them, the solution polymerization method is preferably used in view of production cost and productivity improvement.
As the acrylic polymer obtained by the aforementioned method, a polymer having a weight average molecular weight in the range of 30 to 150 ten thousand is preferably used, and a polymer having a weight average molecular weight in the range of 50 to 120 ten thousand is more preferably used.
As the adhesive composition that can be used for forming the conductive adhesive layer, a composition containing various additives can be used as necessary.
As the additive, for example, a tackifier resin-containing substance can be used in order to further improve the adhesive force of the conductive adhesive layer.
As the tackifier resin, a rosin resin, a terpene resin, an aliphatic (C5 series), aromatic (C9 series) petroleum resin, a styrene resin, a phenol resin, a xylene resin, a methacrylic resin, or the like can be used, and a rosin resin is preferably used, and a polymerized rosin resin is more preferably used.
The tackifier resin is preferably used in a range of 10 to 50 parts by mass with respect to 100 parts by mass of the acrylic polymer.
As the additives, in addition to the foregoing, a dispersant, an anti-settling agent, a plasticizer, a softener, a metal deactivator, an antioxidant, a pigment, a dye, and the like may be used as necessary.
The dispersant and the anti-settling agent are preferably used in preventing the conductive particles contained in the adhesive composition from settling over time.
As the anti-settling agent, for example, a fatty acid amide resin, a polyurethane resin, or the like is preferably used.
The anti-settling agent is preferably used in a range of 0.5 to 10% by mass, more preferably 1 to 6% by mass, and still more preferably 1.5 to 3% by mass, based on the solid content of the binder component.
As the adhesive composition that can be used for forming the conductive adhesive layer, a composition containing a crosslinking agent can be used as necessary.
Examples of the crosslinking agent include isocyanate crosslinking agents, epoxy crosslinking agents, chelate crosslinking agents, and aziridine crosslinking agents.
The kind and amount of the crosslinking agent are preferably selected appropriately according to the kind and amount of the functional group contained in the adhesive component such as the acrylic polymer.
The crosslinking agent can be used by appropriately adjusting the gel fraction of the conductive adhesive layer so as to be in the range of 25 to 60 mass%.
(gel fraction of conductive adhesive layer)
In terms of exhibiting further excellent cohesive force, the conductive adhesive layer preferably has a three-dimensional crosslinked structure. As an index of the formation of the crosslinked structure, there can be mentioned a gel fraction indicating an insoluble component when the conductive adhesive layer is immersed in toluene, which is a good solvent for a (meth) acrylic adhesive, for example, for 24 hours. The gel fraction of the conductive adhesive layer is preferably 10 to 40% by mass, and is more preferably 15 to 30% by mass because the cohesive force in the shear direction can be further increased and the peeling resistance can be improved.
The gel fraction was calculated by the following formula.
Gel fraction (% by mass) { (mass of the conductive adhesive layer after immersion in toluene)/(mass of the conductive adhesive layer before immersion in toluene) } × 100
The mass of the conductive adhesive layer (mass of conductive thin adhesive sheet) - (mass of conductive substrate)
The adhesive composition that can be used for forming the conductive adhesive layer can be produced by, for example, mixing the composition containing the acrylic polymer with the conductive particles.
Examples of the mixing method include a method of mixing and dispersing the composition containing the acrylic polymer and the like, the conductive particles, and if necessary, additives, for example, with a dispersion mixer or the like. Examples of the dispersing mixer include a dissolver, a butterfly mixer, a BDM double-shaft mixer, and a planetary mixer manufactured in the above-well, and a dissolver or a butterfly mixer which does not thicken conductive particles such as metal powder and is easily and uniformly dispersed is preferably used.
As the adhesive composition that can be used for forming the conductive adhesive layer, a composition having a viscosity in a range of 100 to 8000mPa · s is preferably used, and a composition having a viscosity in a range of 200 to 4000mPa · s is more preferably used, and a composition having a viscosity in a range of 200 to 1000mPa · s is preferably used in terms of preventing the conductive particles from settling over time and preventing coating streaks from occurring when the adhesive composition is applied.
The method for adjusting the viscosity of the adhesive composition to the above range includes a method for adjusting the kind and amount of the solvent, the kind of the adhesive substance such as an acrylic polymer, the molecular weight thereof, and the like, and preferably a method for adjusting the kind and amount of the solvent.
The nonvolatile component of the pressure-sensitive adhesive composition is not particularly limited, but is preferably in the range of 10 to 35% by mass, more preferably in the range of 10 to 30% by mass, and still more preferably in the range of 10 to 20% by mass.
(conductive substrate)
Examples of the conductive substrate used for producing the conductive thin adhesive sheet of the present invention include a metal substrate and a graphite substrate.
As the metal base material, for example, a base material made of gold, silver, copper, aluminum, nickel, iron, tin, an alloy thereof, or the like can be used, and when a base material made of aluminum or copper is used, the conductive base material is preferable because the conductive base material is excellent in workability and low in cost.
As the base material made of copper, for example, a base material made of electrolytic copper, a base material made of rolled copper, or the like can be used.
As the base material made of electrolytic copper, CF-T9FZ-HS-12 (thickness: 12 μm), CF-T8G-DK-18 (thickness: 18 μm), CF-T8G-DK-35 (thickness: 35 μm) manufactured by Futian Metal foil powder industries, Ltd., and the like can be used.
As the rolled copper foil, TCU-H-8-RT (thickness 8 μm) manufactured by Nippon Takara K.K., TPC (thickness 6 μm) manufactured by JX Nikko Metal K.K., and the like can be used.
The conductive substrate is preferably 1 to 30 μm thick, more preferably 3 to 25 μm thick, and a metal foil or the like having a thickness of 5 to 20 μm is more preferably used in order to obtain a conductive thin adhesive sheet which is thin and excellent in processability.
(Release liner)
A release liner may be laminated on the surface of the conductive adhesive layer constituting the conductive thin adhesive sheet of the present invention as needed.
The release liner is not particularly limited, and for example, paper such as kraft paper, cellophane paper, and coated paper; resin films such as polyethylene, polypropylene (OPP, CPP), and polyethylene terephthalate; a laminated paper obtained by laminating the paper and a resin film; a filling treatment of the surface of the paper with clay, polyvinyl alcohol, or the like; and a conventionally known gasket obtained by subjecting one or both surfaces subjected to the filling treatment to a peeling treatment with a silicone resin or the like.
The conductive thin adhesive sheet of the present invention can be produced, for example, by applying the adhesive composition containing conductive particles to one or both surfaces of the conductive substrate and drying the adhesive composition (so-called direct coating method).
The conductive thin adhesive sheet of the present invention can be produced by the following method: the adhesive composition containing the conductive particles is applied to the surface of a release liner in advance and dried to form a conductive adhesive layer, and then the conductive adhesive layer is transferred to one surface or both surfaces of the conductive substrate (so-called transfer method).
In order to allow the crosslinking reaction of the conductive adhesive layer to proceed, it is preferable that the conductive thin adhesive sheet produced by any one of the methods is subsequently cured at 20 to 50 ℃ for 48 hours or more.
Examples of the method of applying the conductive adhesive composition to the release liner or the conductive substrate include a method of applying the composition using a comma coater, a method of applying the composition using a gravure coater, and a method of applying the composition using a die lip coater. Among these methods, a method of coating using a gravure coater or a method of coating using a die lip coater is preferably used as the coating method, and a method of coating using a microgravure coater is more preferably used in terms of enabling the thickness of the conductive adhesive layer to be formed with high accuracy and, as a result, achieving both further excellent conductivity and adhesiveness.
Fig. 1 and 2 show examples of preferred configurations of the conductive thin adhesive sheet of the present invention. Fig. 1 shows a single-sided adhesive sheet in which a conductive adhesive layer 2 is laminated on a conductive substrate 1. Fig. 2 shows a double-sided adhesive sheet in which conductive adhesive layers 2 are laminated on both sides of a conductive substrate 1. Among these configurations, a configuration in which a release liner is provided on the surface of the adhesive layer 2 can be preferably used.
Examples
The present invention is not limited to the examples, which are described below in detail.
(preparation of acrylic pressure-sensitive adhesive composition 1)
In a reaction vessel equipped with a cooling tube, a stirrer, a thermometer and a dropping funnel, 75.0 parts by mass of n-butyl acrylate, 19.0 parts by mass of 2-ethylhexyl acrylate, 3.9 parts by mass of vinyl acetate, 2.0 parts by mass of acrylic acid, 0.1 part by mass of 2-hydroxyethyl acrylate and 0.1 part by mass of 2, 2' -azobisisobutyronitrile as a polymerization initiator were dissolved in 100 parts by mass of ethyl acetate, and after nitrogen substitution, polymerization was carried out at 80 ℃ for 12 hours to obtain an ethyl acetate solution of an acrylic polymer having a weight average molecular weight of 60 ten thousand.
The acrylic pressure-sensitive adhesive composition 1 was obtained by mixing 10 parts by mass of PENCEL D-135 (pentaerythritol polymerized rosin, manufactured by Mitsukawa chemical Co., Ltd., softening point 135 ℃) and 10 parts by mass of SUPER ESTER A-100 (glycerol disproportionated rosin, manufactured by Mitsukawa chemical Co., Ltd., softening point 100 ℃) with 100 parts by mass of the solid content of the ethyl acetate solution of the acrylic polymer, and adjusting the solid content concentration of the acrylic polymer to 40% by mass with ethyl acetate.
[ preparation of conductive adhesive composition ]
(preparation of conductive adhesive composition A)
The conductive adhesive composition A was prepared by mixing 100 parts by mass of the acrylic adhesive composition 1, 0.4 parts by mass of Ni powder NI255T (d 50: 26.0 μm) manufactured by Futian Metal foil industries, Inc., as beaded conductive particles, 2 parts by mass of BURNOCK NC40 (isocyanate-based crosslinking agent manufactured by DIC corporation, 40% by mass as a solid content) as a crosslinking agent, and 70 parts by mass of ethyl acetate as a diluent solvent for 10 minutes using a dispersion mixer.
(preparation of conductive adhesive composition B)
The conductive adhesive composition B was prepared by mixing 100 parts by mass of the acrylic adhesive composition 1, 2.0 parts by mass of Ni powder NI255T (d 50: 26.0 μm) manufactured by Futian Metal foil industries, Inc., as beaded conductive particles, 2 parts by mass of BURNOCK NC40 (isocyanate-based crosslinking agent manufactured by DIC corporation, 40% by mass as a solid content) as a crosslinking agent, and 70 parts by mass of ethyl acetate as a diluent solvent for 10 minutes using a dispersion mixer.
(preparation of conductive adhesive composition C)
Conductive adhesive composition C was prepared by mixing 100 parts by mass of acrylic adhesive composition 1, 0.4 parts by mass of Ni powder NI255T-280(d 50: 15.0 μm) manufactured by Futian Metal foil industries, Inc., as beaded conductive particles, 2 parts by mass of BURNOCK NC40 (isocyanate-based crosslinking agent manufactured by DIC corporation, 40% by mass as a solid content) as a crosslinking agent, and 70 parts by mass of ethyl acetate as a diluent solvent for 10 minutes using a dispersion mixer.
(preparation of conductive adhesive composition D)
Conductive adhesive composition D was prepared by mixing 100 parts by mass of acrylic adhesive composition 1, 0.4 parts by mass of Ni powder NI255T-350 (D50: 13.0 μm) manufactured by Futian Metal foil industries, Inc., as beaded conductive particles, 2 parts by mass of BURNOCK NC40 (isocyanate-based crosslinking agent manufactured by DIC corporation, 40% by mass as a solid content) as a crosslinking agent, and 70 parts by mass of ethyl acetate as a diluent solvent for 10 minutes using a dispersion mixer.
(preparation of conductive adhesive composition E)
Conductive adhesive composition E was prepared by mixing 100 parts by mass of acrylic adhesive composition 1, 4.0 parts by mass of nickel powder NI123(d 50: 12.0 μm) manufactured by Futian Metal foil industries, Inc. as spherical conductive particles, 2 parts by mass of BURNOCK NC40 (isocyanate-based crosslinking agent manufactured by DIC corporation, solid content 40 mass%) as a crosslinking agent, and 70 parts by mass of ethyl acetate as a diluent solvent for 10 minutes using a dispersion mixer.
(preparation of conductive adhesive composition F)
The acrylic pressure-sensitive adhesive composition 1, 6.0 parts by mass of nickel powder NI255T (d 50: 26.0 μm) manufactured by Futian Metal foil industries, 2 parts by mass of BURNOCK NC40 (isocyanate-based crosslinking agent manufactured by DIC Co., Ltd., solid content 40% by mass), and 70 parts by mass of ethyl acetate as a diluent solvent were mixed for 10 minutes by a dispersion mixer to prepare a conductive pressure-sensitive adhesive composition E.
(preparation of conductive adhesive composition G)
The conductive adhesive composition G was prepared by mixing 100 parts by mass of the acrylic adhesive composition 1, 6.0 parts by mass of nickel powder NI123(d 50: 12.0 μm) manufactured by Futian Metal foil industries, Inc. as spherical conductive particles, 2 parts by mass of BURNOCK NC40 (isocyanate-based crosslinking agent manufactured by DIC corporation, solid content 40 mass%) as a crosslinking agent, and 70 parts by mass of ethyl acetate as a diluent solvent for 10 minutes using a dispersion mixer.
(preparation of conductive adhesive composition H)
A conductive adhesive composition H was prepared by mixing 100 parts by mass of the acrylic adhesive composition 1, 0.02 part by mass of nickel powder NI255T (d 50: 26.0 μm) manufactured by Futian Metal foil industries, 2 parts by mass of BURNOCK NC40 (isocyanate-based crosslinking agent manufactured by DIC corporation, solid content 40 mass%) as a crosslinking agent, and 70 parts by mass of ethyl acetate as a diluent solvent for 10 minutes using a dispersion mixer.
(example 1)
[ production of electroconductive thin adhesive sheet ]
The conductive adhesive composition A was coated on a release film "PET 38X 1A 3" manufactured by NIPPA corporation by a comma coater so that the thickness of the conductive adhesive layer after drying became 6 μm, dried in a dryer at 80 ℃ for 2 minutes, and then bonded to both sides of an electrolytic copper foil (manufactured by Futian Metal foil powder industries Co., Ltd., CF-T9FZ-HS-12) having a thickness of 15 μm, and then cured at 40 ℃ for 48 hours, thereby obtaining a conductive thin adhesive sheet.
(example 2)
A conductive thin adhesive sheet was obtained in the same manner as in example 1, except that the conductive adhesive composition B was used instead of the conductive adhesive composition a.
(example 3)
A conductive thin adhesive sheet was obtained in the same manner as in example 1, except that the conductive adhesive composition C was used instead of the conductive adhesive composition a.
(example 4)
A conductive thin adhesive sheet was obtained in the same manner as in example 1, except that the conductive adhesive composition D was used instead of the conductive adhesive composition a.
(example 5)
A conductive thin adhesive sheet was obtained in the same manner as in example 1, except that the thickness of the conductive adhesive layer after drying was set to 10 μm.
(example 6)
A conductive thin adhesive sheet was obtained in the same manner as in example 1, except that the conductive adhesive composition E was used instead of the conductive adhesive composition a.
(example 7)
A conductive thin adhesive sheet was obtained in the same manner as in example 1 except that the laminated electrolytic copper foil was changed to CF-T8G-DK-18 (thickness: 18 μm) manufactured by Futian Metal foil powder industries, Ltd., CF-T9FZ-HS-12 manufactured by Futian Metal foil powder industries, Ltd., and the laminated surface was changed to only one surface.
Comparative example 1
A conductive thin adhesive sheet was obtained in the same manner as in example 1, except that the conductive adhesive composition F was used instead of the conductive adhesive composition a.
Comparative example 2
A conductive thin adhesive sheet was obtained in the same manner as in example 1 except that the laminated electrolytic copper foil was changed to CF-T8G-DK-35 (thickness: 35 μm) manufactured by Fuda Metal foil powder industries, Ltd., CF-T9FZ-HS-12 manufactured by Fuda Metal foil powder industries, Ltd., and the thickness of the conductive adhesive layer after drying was changed to 10 μm.
Comparative example 3
A conductive thin adhesive sheet was obtained in the same manner as in example 1, except that the conductive adhesive composition G was used instead of the conductive adhesive composition a.
Comparative example 4
A conductive thin adhesive sheet was obtained in the same manner as in example 1, except that the conductive adhesive composition E was used instead of the conductive adhesive composition a, and the thickness of the dried conductive adhesive layer was set to 15 μm.
Comparative example 5
A conductive thin adhesive sheet was obtained in the same manner as in example 1, except that a conductive adhesive composition H was used instead of the conductive adhesive composition a, and the bonded copper foil was TPC (thickness 6 μm) manufactured by JX riyaite metal co.
Comparative example 6
A conductive thin adhesive sheet was obtained in the same manner as in example 1, except that the thickness of the conductive adhesive layer after drying was set to 0.5 μm.
(evaluation)
The conductive adhesive sheets obtained in examples and comparative examples were evaluated for total thickness, conductivity, and adhesive strength.
[ Total thickness of conductive adhesive sheet ]
The total thickness of the conductive adhesive sheet was measured by using a thickness meter "TH-102" (manufactured by TESTER INDUSTRIAL CO., LTD.).
[ thickness of adhesive layer ]
A part of the conductive adhesive layer formed on the surface of the release liner used in the production of the conductive adhesive sheets in the examples and comparative examples was extracted, and one surface of the extracted part was mounted on a backing (coating ち) by S25 (manufactured by UNITIKA, polyethylene terephthalate film, thickness: 25 μm).
The release liner was peeled off from the sample, and the thickness thereof was measured by using a thickness meter "TH-102" (manufactured by TESTER industries), and the value obtained by subtracting the thickness of S25 was defined as the thickness of the conductive adhesive layer.
[ method for evaluating conductivity (measurement of resistance value) ]
A brass electrode having a length of 10mm x a width of 10mm was attached to one surface of a conductive adhesive sheet having a width of 10mm x a width of 10mm, the surface being formed of a conductive adhesive layer.
A copper foil (thickness: 35 μm) having a length of 7.5 mm. times.7.5 mm was attached to the other surface of the conductive adhesive sheet.
The resistance was measured by connecting terminals to the brass electrode and the copper foil under a load of a surface pressure of 20N from the upper surface of the brass electrode in an atmosphere of 23 ℃ and 50% RH, and applying a current of 10. mu.A using a Milliohm Meter (manufactured by NF Circuit design group, Ltd.). The case where the resistance value was 40m Ω or less was evaluated as excellent conductivity. After 30 days, the resistance value was measured again. The case where the resistance value was 120m Ω or less was evaluated as excellent stability with time of conductivity.
(method of evaluating adhesiveness)
A conductive adhesive sheet having a width of 20mm was attached to the surface of a stainless steel plate (hereinafter referred to as "stainless steel plate") subjected to sanding and polishing with No. 360 water-resistant polishing paper, and pressed by a 2.0kg roller in a reciprocal manner 1 time at 23 ℃ and 60% RH.
After the sticker was left to stand at room temperature for 1 hour, 180-degree peel adhesion was measured at room temperature at a tensile rate of 300mm/min using a tensile tester (Tensilon RTA-100, manufactured by A & D). When a double-sided adhesive sheet was used as the conductive adhesive sheet, the conductive adhesive layer attached to the side opposite to the surface of the stainless steel plate was backed up with S25 (manufactured by UNITIKA corporation, polyethylene terephthalate film having a thickness of 25 μm).
(evaluation criteria for adhesion)
Very good: 7N/20mm or more
O: 5N/20mm or more and less than 7N/20mm
X: less than 4N/20mm
[ Table 1]
[ Table 2]
Claims (6)
1. A conductive adhesive sheet having a conductive base material and 1 or 2 or more conductive adhesive layers, and having a total thickness of 50 [ mu ] m or less, wherein each layer of the conductive adhesive layer contains 0.01 to 10 mass% of at least 1 type of conductive particles, the thickness of each layer of the conductive adhesive layer is 1 to 12 [ mu ] m, and the particle diameter d50 of the conductive particles is 12 to 30 [ mu ] m.
2. The conductive adhesive sheet according to claim 1, wherein the conductive particles have a beaded shape.
3. The conductive adhesive sheet according to claim 1 or 2, wherein the particle diameter d50 of the conductive particles is 100% to 500% of the thickness of the adhesive layer containing the particles.
4. The conductive adhesive sheet according to claim 1 or 2, wherein the conductive substrate is a metal substrate.
5. The conductive adhesive sheet according to claim 1 or 2, wherein the conductive adhesive layer is an adhesive layer formed using an acrylic adhesive composition containing an acrylic polymer.
6. A portable electronic device comprising the conductive adhesive sheet according to any one of claims 1 to 5.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2017117730A JP6930239B2 (en) | 2017-06-15 | 2017-06-15 | Conductive adhesive sheet |
| JP2017-117730 | 2017-06-15 | ||
| CN201810523726.1A CN109135601B (en) | 2017-06-15 | 2018-05-28 | Conductive adhesive sheet |
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| Application Number | Title | Priority Date | Filing Date |
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| CN201810523726.1A Division CN109135601B (en) | 2017-06-15 | 2018-05-28 | Conductive adhesive sheet |
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| CN114015375A true CN114015375A (en) | 2022-02-08 |
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| Application Number | Title | Priority Date | Filing Date |
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| CN202111478724.3A Pending CN114015375A (en) | 2017-06-15 | 2018-05-28 | Conductive adhesive sheet and portable electronic device |
| CN201810523726.1A Active CN109135601B (en) | 2017-06-15 | 2018-05-28 | Conductive adhesive sheet |
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| Application Number | Title | Priority Date | Filing Date |
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| CN201810523726.1A Active CN109135601B (en) | 2017-06-15 | 2018-05-28 | Conductive adhesive sheet |
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| JP (2) | JP6930239B2 (en) |
| KR (1) | KR102530373B1 (en) |
| CN (2) | CN114015375A (en) |
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| JP7528433B2 (en) * | 2019-12-11 | 2024-08-06 | Dic株式会社 | Conductive adhesive sheet |
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| CN103421439A (en) * | 2012-05-23 | 2013-12-04 | Dic株式会社 | Electtroconductive thin adhesive sheet |
| CN103666306A (en) * | 2012-09-13 | 2014-03-26 | Dic株式会社 | Bonding sheet, electromagnetic wave shielding sheet and electronic equipment |
| JP2015010109A (en) * | 2013-06-26 | 2015-01-19 | 日東電工株式会社 | Conductive adhesive tape |
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| JPS63126299A (en) * | 1987-10-23 | 1988-05-30 | カネボウ株式会社 | Molded article for shielding |
| JP4403360B2 (en) * | 2003-02-28 | 2010-01-27 | Ｄｉｃ株式会社 | Conductive adhesive sheet |
| JP2005183883A (en) * | 2003-12-24 | 2005-07-07 | Aica Kogyo Co Ltd | Sheet for electromagnetic wave shield, and its manufacturing method |
| JP5291316B2 (en) | 2007-09-26 | 2013-09-18 | 日東電工株式会社 | Conductive adhesive tape |
| JP2012007093A (en) * | 2010-06-25 | 2012-01-12 | Nitto Denko Corp | Conductive adhesive tape |
| JP2013014734A (en) * | 2011-07-06 | 2013-01-24 | Nitto Denko Corp | Conductive pressure-sensitive adhesive tape |
| JP5884607B2 (en) * | 2012-03-30 | 2016-03-15 | デクセリアルズ株式会社 | Method for producing double-sided adhesive tape |
| KR102061585B1 (en) * | 2013-04-19 | 2020-01-03 | 디아이씨 가부시끼가이샤 | Conductive adhesive sheet, method for manufacturing same and electronic terminal obtained by using same |
| JP2014234444A (en) * | 2013-05-31 | 2014-12-15 | 日東電工株式会社 | Electroconductive double-sided adhesive tape |
| JP2017503899A (en) * | 2014-01-24 | 2017-02-02 | スリーエム イノベイティブ プロパティズ カンパニー | Conductive adhesive tape and article thereof |
| JP6427968B2 (en) * | 2014-06-09 | 2018-11-28 | 大日本印刷株式会社 | Antireflection film and display |
| KR20180021706A (en) * | 2015-06-26 | 2018-03-05 | 니폰 제온 가부시키가이샤 | Antistatic film, method of manufacturing the same, polarizing plate and liquid crystal display device |
| WO2017170371A1 (en) * | 2016-03-30 | 2017-10-05 | 積水化学工業株式会社 | Electroconductive adhesive tape |
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2017
- 2017-06-15 JP JP2017117730A patent/JP6930239B2/en active Active
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- 2018-05-28 CN CN202111478724.3A patent/CN114015375A/en active Pending
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| CN103421439A (en) * | 2012-05-23 | 2013-12-04 | Dic株式会社 | Electtroconductive thin adhesive sheet |
| CN103666306A (en) * | 2012-09-13 | 2014-03-26 | Dic株式会社 | Bonding sheet, electromagnetic wave shielding sheet and electronic equipment |
| JP2015010109A (en) * | 2013-06-26 | 2015-01-19 | 日東電工株式会社 | Conductive adhesive tape |
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| Publication number | Publication date |
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| JP2021183698A (en) | 2021-12-02 |
| CN109135601B (en) | 2021-11-26 |
| KR20180136882A (en) | 2018-12-26 |
| JP7363864B2 (en) | 2023-10-18 |
| JP6930239B2 (en) | 2021-09-01 |
| CN109135601A (en) | 2019-01-04 |
| JP2019001909A (en) | 2019-01-10 |
| KR102530373B1 (en) | 2023-05-09 |
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