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WO2019151398A1 - Electroconductive pressure-sensitive adhesive tape - Google Patents

Electroconductive pressure-sensitive adhesive tape Download PDF

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Publication number
WO2019151398A1
WO2019151398A1 PCT/JP2019/003396 JP2019003396W WO2019151398A1 WO 2019151398 A1 WO2019151398 A1 WO 2019151398A1 JP 2019003396 W JP2019003396 W JP 2019003396W WO 2019151398 A1 WO2019151398 A1 WO 2019151398A1
Authority
WO
WIPO (PCT)
Prior art keywords
sensitive adhesive
pressure
adhesive layer
adhesive tape
weight
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Ceased
Application number
PCT/JP2019/003396
Other languages
French (fr)
Japanese (ja)
Inventor
桃子 伊達木
勇樹 岩井
豊嶋　克典
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Sekisui Chemical Co Ltd
Original Assignee
Sekisui Chemical Co Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
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Application filed by Sekisui Chemical Co Ltd filed Critical Sekisui Chemical Co Ltd
Priority to JP2019517856A priority Critical patent/JPWO2019151398A1/en
Priority to KR1020207010093A priority patent/KR20200112801A/en
Priority to CN201980004833.6A priority patent/CN111164175B/en
Publication of WO2019151398A1 publication Critical patent/WO2019151398A1/en
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

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Classifications

    • 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
    • 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
    • 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
    • C09J133/04—Homopolymers or copolymers of esters
    • 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
    • C09J133/04—Homopolymers or copolymers of esters
    • C09J133/06—Homopolymers or copolymers of esters of esters containing only carbon, hydrogen and oxygen, the oxygen atom being present only as part of the carboxyl radical
    • 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
    • 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
    • C09J7/38—Pressure-sensitive adhesives [PSA]
    • 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
    • C09J7/38—Pressure-sensitive adhesives [PSA]
    • C09J7/381—Pressure-sensitive adhesives [PSA] based on macromolecular compounds obtained by reactions involving only carbon-to-carbon unsaturated bonds
    • C09J7/385—Acrylic polymers
    • 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
    • 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
    • C09J2301/312—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 parameters being the characterizing feature

Definitions

  • the present invention relates to a conductive adhesive tape.
  • Electronic board components constituting an electronic device have been highly integrated, and a CPU, a connector, and the like and an antenna portion may be arranged close to each other.
  • noise countermeasures such as covering the CPU, the connector, etc. with the electromagnetic shielding material or performing grounding are performed. Yes.
  • Patent Document 1 describes a conductive pressure-sensitive adhesive sheet having a total thickness of 30 ⁇ m or less and having a conductive base material and a conductive pressure-sensitive adhesive layer containing conductive particles.
  • the conductive pressure-sensitive adhesive sheet Describes that it has excellent adhesion and conductivity to an adherend while being extremely thin.
  • An object of this invention is to provide the electroconductive adhesive tape excellent in electromagnetic wave shielding property and electroconductivity.
  • the present invention is a conductive pressure-sensitive adhesive tape having a conductive base material and a pressure-sensitive adhesive layer disposed on at least one surface of the conductive base material, the pressure-sensitive adhesive layer comprising an acrylic copolymer, It is a conductive adhesive tape containing a metal filler and having an a value calculated by the following formula (1) of 0 or more.
  • M metal amount (volume%) of the metal filler with respect to the volume of the pressure-sensitive adhesive layer
  • D Thickness ( ⁇ m) of the pressure-sensitive adhesive layer
  • d40 Particle size ( ⁇ m) of the metal filler when the volume-based cumulative distribution is 40%
  • d70 Particle diameter ( ⁇ m) of the metal filler when the cumulative distribution on the basis of volume is 70%
  • the present inventors include an acrylic copolymer, a metal filler, and the pressure-sensitive adhesive layer. Then, the metal amount of the metal filler relative to the volume of the pressure-sensitive adhesive layer, the thickness of the pressure-sensitive adhesive layer, and the particle diameter of the metal filler were studied. As a result, the inventors have determined that a specific formula is derived from these values rather than individual values of the amount of metal of the metal filler, the thickness of the pressure-sensitive adhesive layer, and the particle size of the metal filler relative to the volume of the pressure-sensitive adhesive layer.
  • the electroconductive adhesive tape which is one embodiment of this invention has an electroconductive base material and the adhesive layer arrange
  • the conductive substrate is not particularly limited, and examples thereof include foil-shaped substrates such as metal foils and conductive resin substrates. Especially, it is preferable that metal foil is included, and it is more preferable to consist of metal foil.
  • the material of the said metal foil is not specifically limited, For example, nickel, silver, copper, aluminum etc. are mentioned, Moreover, the alloy of these metals may be sufficient. Especially, since resistance value is stable and electromagnetic wave shielding property is stable in each frequency band, silver and copper, and these alloys are preferable, and copper is more preferable.
  • the conductive substrate may be a single layer or a multilayer, but is preferably a multilayer from the viewpoint of improving heat resistance and rust prevention.
  • the pressure-sensitive adhesive layer may have a metal layer containing zinc and / or nickel.
  • the thickness of the said electroconductive base material is not specifically limited, A preferable minimum is 1 micrometer and a preferable upper limit is 150 micrometers. If the said electroconductive base material is 1 micrometer or more, the intensity
  • the more preferable lower limit of the thickness of the conductive substrate is 5 ⁇ m
  • the more preferable upper limit is 40 ⁇ m
  • the still more preferable lower limit is 9 ⁇ m
  • the still more preferable upper limit is 35 ⁇ m
  • the still more preferable lower limit is 10 ⁇ m
  • the still more preferable upper limit is 30 ⁇ m. It is.
  • the pressure-sensitive adhesive layer may be disposed on one side or both sides of the conductive substrate as long as it is disposed on at least one surface of the conductive substrate.
  • the pressure-sensitive adhesive layers on both sides may be the same composition or different compositions, and at least one pressure-sensitive adhesive layer is a range described later. It is sufficient to have a value of
  • the pressure-sensitive adhesive layer contains an acrylic copolymer and a metal filler.
  • the acrylic copolymer is preferably a copolymer obtained by copolymerizing a monomer mixture containing butyl acrylate (BA) and 2-ethylhexyl acrylate (2EHA).
  • BA butyl acrylate
  • EHA 2-ethylhexyl acrylate
  • the content of butyl acrylate and the content of 2-ethylhexyl acrylate in the total monomer mixture is not particularly limited, but the preferred content of butyl acrylate is 50 to 90% by weight, and the preferred content of 2-ethylhexyl acrylate is 10 to 50% by weight.
  • the monomer mixture may contain other copolymerizable monomers other than butyl acrylate and 2-ethylhexyl acrylate as necessary.
  • the other polymerizable monomer that can be copolymerized include, for example, (meth) acrylic acid alkyl esters having an alkyl group having 1 to 3 carbon atoms, (meth) acrylic acid alkyl esters having an alkyl group having 13 to 18 carbon atoms, Examples include functional monomers. These other polymerizable monomers capable of copolymerization may be used alone or in combination of two or more.
  • Examples of the (meth) acrylic acid alkyl ester having 1 to 3 carbon atoms in the alkyl group include, for example, methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, and (meth) acrylic acid. And isopropyl.
  • Examples of the (meth) acrylic acid alkyl ester having 13 to 18 carbon atoms in the alkyl group include tridecyl methacrylate and stearyl (meth) acrylate.
  • Examples of the functional monomer include hydroxyalkyl (meth) acrylate, glycerin dimethacrylate, glycidyl (meth) acrylate, 2-methacryloyloxyethyl isocyanate, (meth) acrylic acid, itaconic acid, maleic anhydride, crotonic acid, Maleic acid, fumaric acid, etc. are mentioned.
  • the monomer mixture preferably contains 0.1 to 10% by weight of a crosslinkable monomer as required.
  • the monomer mixture contains a crosslinkable monomer in the above range, and the cohesive strength of the conductive adhesive tape obtained can be enhanced, and the electromagnetic wave shielding property and conductivity can be stably suppressed by suppressing the slight floating caused by the metal filler. Can be expressed.
  • the crosslinkable monomer include a carboxyl group-containing monomer, a hydroxyl group-containing monomer, a glycidyl group-containing monomer, and a methylol group-containing monomer.
  • the hydroxyl group-containing monomer examples include hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, 4-butylhydroxy (meth) acrylate and the like.
  • the carboxyl group-containing monomer examples include acrylic acid, methacrylic acid, itaconic acid, maleic anhydride, and the like.
  • the monomer mixture preferably contains a hydroxyl group-containing monomer and a carboxyl group-containing monomer from the viewpoint of increasing the cohesive strength of the pressure-sensitive adhesive tape and at the same time enhancing the electromagnetic wave shielding properties and conductivity.
  • the monomer mixture is more preferably used in combination with hydroxyethyl (meth) acrylate and / or 4-butylhydroxy (meth) acrylate and (meth) acrylic acid.
  • the content of the crosslinkable monomer in the monomer mixture is more preferably 0.5% by weight or more, and still more preferably. 1% by weight or more, still more preferably 2% by weight or more, more preferably 8% by weight or less, still more preferably 6% by weight or less, and still more preferably 4% by weight or less.
  • the content thereof is more preferably 0.1% by weight from the viewpoint of further enhancing the cohesive strength of the pressure-sensitive adhesive tape and at the same time further enhancing the electromagnetic shielding properties and conductivity. Or more, more preferably 0.15% by weight or more, still more preferably 0.2% by weight or more, more preferably 3% by weight or less, still more preferably 2% by weight or less, and even more preferably 1% by weight or less. is there.
  • the content is more preferably 1% by weight or more from the viewpoint of further increasing the cohesive strength of the pressure-sensitive adhesive tape and at the same time further enhancing the electromagnetic shielding properties and conductivity. More preferably, it is 1.5% by weight or more, still more preferably 2% by weight or more, more preferably 8% by weight or less, still more preferably 5% by weight or less, and even more preferably 3% by weight or less.
  • the monomer mixture may be radically reacted in the presence of a polymerization initiator.
  • a method of radical reaction of the monomer mixture that is, a polymerization method
  • examples thereof include solution polymerization (boiling point polymerization or constant temperature polymerization), emulsion polymerization, suspension polymerization, bulk polymerization and the like.
  • the said polymerization initiator is not specifically limited, For example, an organic peroxide, an azo compound, etc. are mentioned.
  • organic peroxide examples include 1,1-bis (t-hexylperoxy) -3,3,5-trimethylcyclohexane, t-hexylperoxypivalate, t-butylperoxypivalate, 2,5 -Dimethyl-2,5-bis (2-ethylhexanoylperoxy) hexane, t-hexylperoxy-2-ethylhexanoate, t-butylperoxy-2-ethylhexanoate, t-butylperoxy Examples include isobutyrate, t-butylperoxy-3,5,5-trimethylhexanoate, and t-butylperoxylaurate.
  • the azo compound examples include azobisisobutyronitrile and azobiscyclohexanecarbonitrile. These polymerization initiators may be used alone or in combination of two or more.
  • the weight average molecular weight (Mw) of the acrylic copolymer is not particularly limited, but a preferred lower limit is 400,000, a preferred upper limit is 1.6 million, a more preferred upper limit is 1.4 million, and a more preferred upper limit is 1,200,000. If the said weight average molecular weight is 400,000 or more, the cohesion force of the said adhesive layer will become high and the adhesive reliability of an electroconductive adhesive tape will improve. If the said weight average molecular weight is 1.6 million or less, the said adhesive layer has sufficient level
  • the more preferable lower limit of the weight average molecular weight is 500,000, and the more preferable lower limit is 700,000.
  • the polymerization conditions such as the polymerization initiator and the polymerization temperature may be controlled.
  • a weight average molecular weight (Mw) is a weight average molecular weight of standard polystyrene conversion by GPC (Gel Permeation Chromatography: gel permeation chromatography).
  • the metal filler may be a filler made of only metal, or may be a filler in which a metal coating is applied to a core (for example, resin particles) other than metal.
  • a metal coating for example, resin particles
  • the metal in the metal filler include nickel, silver, copper, gold, aluminum, iron, tin alloy, titanium, and alloys thereof. Of these, copper, silver, nickel, and alloys thereof are preferable. Furthermore, since copper and silver may cause passivation or the like and the conductivity may be lowered, nickel is more preferable.
  • the shape of the metal filler is not particularly limited, and examples thereof include a spherical shape, an elliptical shape, a needle shape, a square shape, a dendritic shape, a piece shape, an irregular shape, a teardrop shape, and a granular shape.
  • a spherical shape, an elliptical shape, a needle shape, or a granular shape is preferable.
  • the a value is preferably 5 or more, more preferably 7 or more, still more preferably 9 or more, still more preferably 10 or more, particularly preferably 12 or more, and particularly preferably 13 or more. Very preferably 14 or more.
  • the upper limit of the a value is not particularly limited, the preferable upper limit is 200, the more preferable upper limit is 100, and the still more preferable upper limit is 50, from the viewpoint of the electromagnetic shielding property and conductivity of the conductive adhesive tape and the balance of the adhesive performance.
  • the “a value” is the metal amount of the metal filler relative to the volume of the pressure-sensitive adhesive layer in Examples and Comparative Examples, the thickness of the pressure-sensitive adhesive layer, the particle diameter of the metal filler when the volume-based cumulative distribution is 40%, And it is derived by regression analysis from the correlation between the particle diameter of the metal filler when the volume-based cumulative distribution is 70% and the electromagnetic shielding properties. At this time, when the measurement result at 1 GHz was 65 dB or more in the evaluation of the electromagnetic wave shielding property, it was determined that the electromagnetic wave shielding property was sufficient. As the regression analysis, for example, a commonly performed method such as linear regression or nonlinear regression can be employed.
  • a method of increasing the metal amount (M) of the metal filler with respect to the volume of the pressure-sensitive adhesive layer, a method of reducing the thickness (D) of the pressure-sensitive adhesive layer, and the pressure-sensitive adhesive layer A method of increasing the ratio (d70 / D) of the particle diameter (d70) of the metal filler when the volume-based cumulative distribution with respect to the thickness (D) of the metal filler becomes 70% is preferable.
  • the difference between the particle diameter (d70) of the metal filler when the volume-based cumulative distribution is 70% and the particle diameter (d40) of the metal filler when the volume-based cumulative distribution is 40% is also preferable. These methods may be used alone or in combination of two or more.
  • a preferable lower limit of the metal amount (M) of the metal filler with respect to the volume of the pressure-sensitive adhesive layer is 0.001% by volume, and a preferable upper limit is 10% by volume.
  • a conductive path is sufficiently formed in the pressure-sensitive adhesive layer, and the electromagnetic wave shielding property and conductivity of the conductive pressure-sensitive adhesive tape are improved.
  • the amount of the metal is 10% by volume or less, an increase in the resistance value due to the influence of the contact resistance at the interface of the metal filler can be suppressed.
  • a more preferable lower limit of the metal amount is 0.01% by volume, and from the viewpoint of further suppressing an increase in resistance value, A preferred upper limit is 3.5% by volume.
  • the minimum with preferable thickness (D) of the said adhesive layer is 1 micrometer, and a preferable upper limit is 50 micrometers. If the said thickness is 1 micrometer or more, the said adhesive layer has sufficient adhesive force, and the adhesive reliability of an electroconductive adhesive tape will improve. If the said thickness is 50 micrometers or less, the noise radiation from the cross section of the said adhesive layer will be suppressed, and the electromagnetic wave shielding property and electroconductivity of a conductive adhesive tape will improve.
  • the more preferable lower limit of the thickness of the pressure-sensitive adhesive layer is 3 ⁇ m, the more preferable upper limit is 30 ⁇ m, the still more preferable lower limit is 4 ⁇ m, the still more preferable upper limit is 20 ⁇ m, the still more preferable lower limit is 5 ⁇ m, the still more preferable upper limit is 15 ⁇ m, and the particularly preferable upper limit is 14 ⁇ m. It is.
  • the preferable lower limit of the ratio (d70 / D) of the particle diameter (d70) of the metal filler when the volume-based cumulative distribution with respect to the thickness (D) of the pressure-sensitive adhesive layer is 70% is 0.6, and the preferable upper limit is 5 .0.
  • the ratio (d70 / D) is 0.6 or more, the metal filler protrudes from the pressure-sensitive adhesive layer, and the electromagnetic wave shielding property and conductivity of the conductive pressure-sensitive adhesive tape are improved.
  • the ratio (d70 / D) is 5.0 or less, excessive protrusion of the metal filler from the pressure-sensitive adhesive layer is suppressed, and sufficient pressure-sensitive adhesive performance can be maintained.
  • the more preferable lower limit of the ratio (d70 / D) is 0.7, the still more preferable lower limit is 0.75, and the still more preferable lower limit is 0.8.
  • a particularly preferred lower limit is 0.85, a particularly preferred lower limit is 0.9, a very preferred lower limit is 1, and a most preferred lower limit is 1.1.
  • the more preferable upper limit of the ratio (d70 / D) is 5.0, the still more preferable upper limit is 4.0, the still more preferable upper limit is 3.5, and the particularly preferable upper limit is 3.3.
  • the preferred upper limit is 3.2, the very preferred upper limit is 3.1, and the most preferred upper limit is 3.
  • the preferable lower limit of d40) is 0.01 ⁇ m, and the preferable upper limit is 40 ⁇ m.
  • the difference (d70 ⁇ d40) is 0.01 ⁇ m or more, high electromagnetic shielding properties can be exhibited even when the ratio (d70 / D) is small.
  • the difference (d70 ⁇ d40) is 40 ⁇ m or less, the particle size distribution becomes sharp, and the electromagnetic wave shielding property and conductivity of the conductive adhesive tape can be obtained stably.
  • a more preferable lower limit of the difference (d70 ⁇ d40) is 1 ⁇ m, and a more preferable upper limit is 30 ⁇ m.
  • the particle size (d70) of the metal filler when the volume-based cumulative distribution is 70% is preferable because the a value can be easily controlled within the above range regardless of the thickness (D) of the pressure-sensitive adhesive layer.
  • Is 4.0 ⁇ m the preferred upper limit is 50 ⁇ m, the more preferred lower limit is 6.0 ⁇ m, and the more preferred upper limit is 40 ⁇ m.
  • the particle size (d70 and d40) of the metal filler can be obtained by measuring the particle size distribution with a laser diffractometer (for example, SALD-3000 manufactured by Shimadzu Corporation).
  • the particle size of the metal filler in the pressure-sensitive adhesive layer is determined by heating the pressure-sensitive adhesive layer containing the metal filler under an inert gas, pyrolyzing only the components other than the metal filler, collecting only the metal filler, and laser diffractometer. The particle size distribution can be measured.
  • the pressure-sensitive adhesive layer preferably contains a tackifier resin.
  • tackifier resins include rosin ester resins, hydrogenated rosin resins, terpene resins, terpene phenol resins, coumarone indene resins, alicyclic saturated hydrocarbon resins, C5 petroleum resins, and C9 resins. Examples include petroleum resins and C5-C9 copolymer petroleum resins. These tackifying resins may be used alone or in combination of two or more.
  • the tackifier resin is preferably highly polar from the viewpoint of improving adhesiveness and dispersibility of the metal filler.
  • the preferred lower limit of the hydroxyl value is 20, the preferred upper limit is 200, and the more preferred lower limit is 30. A more preferred upper limit is 150.
  • content of the said tackifying resin is not specifically limited,
  • the preferable minimum with respect to 100 weight part of said acrylic copolymers is 5 weight part, and a preferable upper limit is 40 weight part. If the said content is 5 weight part or more, the said adhesive layer has sufficient adhesive force, and the adhesive reliability of an electroconductive adhesive tape will improve. When the content is 40 parts by weight or less, the pressure-sensitive adhesive layer has sufficient step following ability and adhesive force without becoming too hard, and the adhesive reliability of the conductive pressure-sensitive adhesive tape is improved. From the same viewpoint, the more preferable lower limit of the content is 10 parts by weight, and the more preferable lower limit is 30 parts by weight.
  • a crosslinking structure may be formed between main chains of the resin (the acrylic copolymer and / or the tackifying resin) constituting the pressure-sensitive adhesive layer by adding a crosslinking agent.
  • a crosslinking agent is not specifically limited, For example, an isocyanate type crosslinking agent, an aziridine type crosslinking agent, an epoxy-type crosslinking agent, a metal chelate type crosslinking agent etc. are mentioned. Of these, isocyanate-based crosslinking agents are preferred.
  • the isocyanate group of the isocyanate-based crosslinking agent reacts with the alcoholic hydroxyl group in the resin constituting the pressure-sensitive adhesive layer, thereby cross-linking the pressure-sensitive adhesive layer. It becomes loose. Therefore, since the said adhesive layer can disperse the peeling stress added intermittently, the adhesive reliability of an electroconductive adhesive tape improves.
  • the addition amount of the crosslinking agent is preferably 0.01 to 10 parts by weight and more preferably 0.1 to 3 parts by weight with respect to 100 parts by weight of the acrylic copolymer.
  • the pressure-sensitive adhesive layer may contain plasticizers, emulsifiers, softeners, fillers, additives such as pigments and dyes, and other resins such as rosin resins, if necessary.
  • the degree of crosslinking of the pressure-sensitive adhesive layer is not particularly limited, but a preferred lower limit is 20% by weight and a preferred upper limit is 45% by weight. If the said crosslinking degree is 20 weight% or more, the cohesion force of the said adhesive layer will become high and the adhesive reliability of an electroconductive adhesive tape will improve. If the said crosslinking degree is 45 weight% or less, the said adhesive layer has sufficient level
  • the more preferred lower limit of the degree of crosslinking is 25% by weight, the more preferred upper limit is 40% by weight, the still more preferred lower limit is 30% by weight, and the more preferred upper limit is 35% by weight.
  • the degree of cross-linking of the pressure-sensitive adhesive layer was determined by collecting W1 (g) of the pressure-sensitive adhesive layer, immersing this pressure-sensitive adhesive layer in ethyl acetate at 23 ° C. for 24 hours, and filtering the insoluble matter with a 200-mesh wire mesh. The residue on the wire net is vacuum-dried, and the weight W2 (g) of the dry residue is measured, and calculated by the following formula (2).
  • Crosslinking degree (% by weight) 100 ⁇ W2 / W1 (2)
  • a preferable minimum is 2 micrometers and a preferable upper limit is 200 micrometers. If the said total thickness is in the said range, the handleability of an electroconductive adhesive tape will improve.
  • the minimum with said more preferable total thickness is 10 micrometers, and a more preferable upper limit is 50 micrometers.
  • the following methods are mentioned, for example.
  • a solvent is added to an acrylic copolymer, a metal filler, a tackifier resin, a cross-linking agent, etc. as necessary to prepare a solution of the adhesive a, and the solution of the adhesive a is applied to the surface of the conductive substrate.
  • the adhesive layer a is formed by applying and completely removing the solvent in the solution by drying.
  • the release film is superimposed on the formed pressure-sensitive adhesive layer a so that the release treatment surface faces the pressure-sensitive adhesive layer a.
  • a release film different from the above release film is prepared, a solution of the adhesive b is applied to the release treatment surface of the release film, and the solvent in the solution is completely removed by drying, thereby releasing the release film.
  • a laminated film in which the pressure-sensitive adhesive layer b is formed on the surface of the mold film is produced.
  • the obtained laminated film is laminated on the back surface of the conductive base material on which the pressure-sensitive adhesive layer a is formed, and the pressure-sensitive adhesive layer b is superimposed on the back surface of the conductive base material to produce a laminate.
  • the conductive adhesive tape which has an adhesive layer on both surfaces of an electroconductive base material, and the surface of the adhesive layer was covered with the release film is obtained. Can do.
  • two sets of laminated films are produced in the same manner, and these laminated films are laminated on both sides of the conductive base material with the adhesive layer of the laminated film facing the conductive base material.
  • a laminated body may be produced and the laminated body may be pressed by a rubber roller or the like. Thereby, you may obtain the electroconductive adhesive tape which has an adhesive layer on both surfaces of an electroconductive base material, and the surface of the adhesive layer was covered with the release film.
  • the use of the conductive pressure-sensitive adhesive tape according to one embodiment of the present invention is not particularly limited, but since it is excellent in electromagnetic shielding properties and conductivity, in an electronic board component constituting an electronic device, an electronic component (for example, a CPU or a connector). It is preferable to use it as an electromagnetic shielding material.
  • the shape of the conductive adhesive tape in such a CPU cover (shield cap) application is not particularly limited, and examples thereof include a rectangle, a frame shape, a circle, an ellipse, and a donut shape.
  • the sticking area of the conductive adhesive tape which is one embodiment of the present invention is not particularly limited, but is preferably 10,000 mm 2 or less.
  • the electroconductive adhesive tape excellent in electromagnetic wave shielding property and electroconductivity can be provided.
  • Example 1 Preparation of acrylic copolymer-containing solution (a)
  • Ethyl acetate was added as a polymerization solvent in the reaction vessel, and after bubbling with nitrogen, the reaction vessel was heated while flowing nitrogen and refluxing was started. Subsequently, a polymerization initiator solution in which 0.1 part by weight of azobisisobutyronitrile as a polymerization initiator was diluted 10 times with ethyl acetate was charged into the reaction vessel.
  • 2-ethylhexyl acrylate (2-EHA) 30 parts by weight, butyl acrylate (BA) 60 parts by weight, cyclohexyl methacrylate (CHMA) 6.7 parts by weight, acrylic acid (AAC) 3 parts by weight, 4-hydroxybutyl acrylate 0.3 parts by weight of (4-HBA) was added dropwise over 2 hours.
  • a polymerization initiator solution obtained by diluting 0.1 part by weight of azobisisobutyronitrile 10 times with ethyl acetate as a polymerization initiator was charged again into the reaction vessel, and the polymerization reaction was performed for 4 hours.
  • a coalescence-containing solution (a) weight average molecular weight (Mw) of acrylic copolymer: 1,200,000) was obtained.
  • a terpene resin hydroxyl value 130, manufactured by Yasuhara Chemical Co., Ltd., G-150
  • an isocyanate crosslinker manufactured by Tosoh Corporation, Coronate L
  • 50% of ethyl acetate 50% of ethyl acetate as a
  • a weight part was stirred and mixed to prepare an adhesive solution.
  • a PET separator having a thickness of 25 ⁇ m was prepared, and the pressure-sensitive adhesive solution was applied to the release-treated surface of the separator and dried at 110 ° C. for 3 minutes to form a pressure-sensitive adhesive layer.
  • a conductive pressure-sensitive adhesive tape was obtained.
  • the compounding quantity of the metal filler was controlled so that the metal content of the metal filler was 1.10% by volume with respect to the volume of the pressure-sensitive adhesive layer to be formed.
  • a value was computed by Formula (1) mentioned above.
  • Examples 2 to 13, Comparative Examples 1 to 4 A conductive pressure-sensitive adhesive tape was obtained in the same manner as in Example 1 except that the thickness of the pressure-sensitive adhesive layer and the metal filler (type, shape, particle size and blending amount) were changed as shown in Table 1.
  • a conductive pressure-sensitive adhesive tape was obtained in the same manner as in Example 1 except that the thickness of the pressure-sensitive adhesive layer and the metal filler (type, shape, particle size and blending amount) were changed as shown in Table 1.
  • the electromagnetic wave shielding conductive adhesive tape was cut into a flat rectangular shape of 41 mm ⁇ 50 mm to prepare a test piece.
  • a jig for electric field measurement of a KEC apparatus manufactured by Techno Science Japan Co., Ltd.
  • the test piece was affixed to a copper plate according to the hole shape so that the affixing width of each side was 1.5 mm.
  • the jig was covered with an upper lid and tightened sufficiently.
  • the electromagnetic wave shielding property of the test piece was measured from 100 MHz to 8 GHz.
  • a calibration value was obtained when a 3 mm thick copper plate with a 38 mm ⁇ 48 mm hole was installed and no test piece was provided.
  • the measurement result in 1 GHz was 65 dB or more, it judged that it had sufficient electromagnetic wave shielding property.
  • the conductive conductive adhesive tape was cut into a 25 mm ⁇ 75 mm rectangular shape to prepare a test piece.
  • the test piece was affixed on two copper electrodes with a width of 25 mm.
  • the area where the test piece was attached to each electrode was 25 mm ⁇ 25 mm.
  • the resistance value was measured in a test room at a temperature of 23 ° C. and a humidity of 50% RH. In addition, it means that it is excellent in electroconductivity, so that resistance value is low. When the measurement limit was exceeded and the resistance value could not be measured, “OL” was indicated.
  • the electroconductive adhesive tape excellent in electromagnetic wave shielding property and electroconductivity can be provided.

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  • Chemical & Material Sciences (AREA)
  • Organic Chemistry (AREA)
  • Inorganic Chemistry (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Adhesive Tapes (AREA)
  • Shielding Devices Or Components To Electric Or Magnetic Fields (AREA)
  • Adhesives Or Adhesive Processes (AREA)

Abstract

The purpose of the present invention is to provide an electroconductive pressure-sensitive adhesive tape excellent in terms of electromagnetic shielding property and electroconductivity. The present invention is an electroconductive pressure-sensitive adhesive tape which comprises an electroconductive substrate and a pressure-sensitive adhesive layer disposed on at least one surface of the electroconductive substrate, wherein the pressure-sensitive adhesive layer comprises an acrylic copolymer and a metallic filler and has a value of "a" calculated with equation (1) of 0 or greater. Value of a = (25×M)+{22×(d70/D)}-3×(d70-d40)-18 (1) M: Amount (vol%) of the metal contained in the metallic filler with respect to the volume of the pressure-sensitive adhesive layer D: Thickness (μm) of the pressure-sensitive adhesive layer d40: Particle diameter (μm) of the metallic filler at 40% volume-cumulative distribution d70: Particle diameter (μm) of the metallic filler at 70% volume-cumulative distribution

Description

導電性粘着テープConductive adhesive tape

本発明は、導電性粘着テープに関する。 The present invention relates to a conductive adhesive tape.

電子機器を構成する電子基板部品は高集積化が進んでおり、ＣＰＵやコネクタ等とアンテナ部分とが近接して配置されることがある。このような場合、ＣＰＵやコネクタ等から発せられる電磁波（ノイズ）に起因する誤動作を抑制するために、電磁波シールド材によりＣＰＵやコネクタ等を覆ったり、グランディングを行ったりするノイズ対策が行われている。 Electronic board components constituting an electronic device have been highly integrated, and a CPU, a connector, and the like and an antenna portion may be arranged close to each other. In such a case, in order to suppress malfunction caused by electromagnetic waves (noise) emitted from the CPU, the connector, etc., noise countermeasures such as covering the CPU, the connector, etc. with the electromagnetic shielding material or performing grounding are performed. Yes.

電磁波シールド材として、例えば、銅箔、アルミ箔等の金属箔に粘着剤層が積層された導電性粘着テープが用いられている。特許文献１には、総厚さが３０μｍ以下であり、導電性基材と、導電性粒子を含有する導電性粘着剤層とを有する導電性粘着シートが記載されており、該導電性粘着シートは極薄型でありながら、被着体への良好な接着性と導電性とを有していることが記載されている。 As the electromagnetic shielding material, for example, a conductive adhesive tape in which an adhesive layer is laminated on a metal foil such as a copper foil or an aluminum foil is used. Patent Document 1 describes a conductive pressure-sensitive adhesive sheet having a total thickness of 30 μm or less and having a conductive base material and a conductive pressure-sensitive adhesive layer containing conductive particles. The conductive pressure-sensitive adhesive sheet Describes that it has excellent adhesion and conductivity to an adherend while being extremely thin.

国際公開第２０１５／０７６１７４号International Publication No. 2015/076174

導電性粘着テープの性能を示す物性としては、特許文献１にも記載されているように電磁波シールド性を代替的に示す物性として導電性（抵抗値測定）が多用されている。
これに対して、本発明者らは、導電性（抵抗値測定）に加えて実際の電磁波シールド性についても詳細に評価した。その結果、本発明者らは、導電性粘着テープは粘着剤層を有するため貼り付けて使用できるという利点がある一方で、粘着剤層の断面が露出していると、その断面が電磁波（ノイズ）の放射源となってノイズ放射が生じやすく、電磁波シールド性が充分に得られないという問題を見出した。 As a physical property indicating the performance of the conductive pressure-sensitive adhesive tape, as described in Patent Document 1, electrical conductivity (resistance value measurement) is frequently used as a physical property that alternatively indicates electromagnetic shielding properties.
On the other hand, the present inventors evaluated in detail about the actual electromagnetic wave shielding property in addition to electroconductivity (resistance value measurement). As a result, the present inventors have an advantage that the conductive adhesive tape has an adhesive layer and can be used by being attached. On the other hand, when the cross section of the adhesive layer is exposed, the cross section becomes an electromagnetic wave (noise). ) Radiation sources, noise emission is likely to occur, and electromagnetic wave shielding properties cannot be obtained sufficiently.

本発明は、電磁波シールド性及び導電性に優れた導電性粘着テープを提供することを目的とする。 An object of this invention is to provide the electroconductive adhesive tape excellent in electromagnetic wave shielding property and electroconductivity.

本発明は、導電性基材と、前記導電性基材の少なくとも一方の面に配置された粘着剤層とを有する導電性粘着テープであって、前記粘着剤層は、アクリル共重合体と、金属フィラーとを含有し、下記式（１）により算出したａ値が０以上である導電性粘着テープである。
ａ値＝（２５×Ｍ）＋｛２２×（ｄ７０／Ｄ）｝－３×（ｄ７０－ｄ４０）－１８　　（１）
Ｍ：前記粘着剤層の体積に対する前記金属フィラーの金属量（体積％）
Ｄ：前記粘着剤層の厚み（μｍ）
ｄ４０：体積基準の累積分布が４０％となるときの前記金属フィラーの粒子径（μｍ）
ｄ７０：体積基準の累積分布が７０％となるときの前記金属フィラーの粒子径（μｍ）
以下、本発明を詳述する。 The present invention is a conductive pressure-sensitive adhesive tape having a conductive base material and a pressure-sensitive adhesive layer disposed on at least one surface of the conductive base material, the pressure-sensitive adhesive layer comprising an acrylic copolymer, It is a conductive adhesive tape containing a metal filler and having an a value calculated by the following formula (1) of 0 or more.
a value = (25 × M) + {22 × (d70 / D)} − 3 × (d70−d40) −18 (1)
M: metal amount (volume%) of the metal filler with respect to the volume of the pressure-sensitive adhesive layer
D: Thickness (μm) of the pressure-sensitive adhesive layer
d40: Particle size (μm) of the metal filler when the volume-based cumulative distribution is 40%
d70: Particle diameter (μm) of the metal filler when the cumulative distribution on the basis of volume is 70%
The present invention is described in detail below.

本発明者らは、導電性基材と、導電性基材の少なくとも一方の面に配置された粘着剤層とを有する導電性粘着テープにおいて、粘着剤層にアクリル共重合体と、金属フィラーとを含有させたうえで、粘着剤層の体積に対する金属フィラーの金属量、粘着剤層の厚み、及び、金属フィラーの粒子径を制御することを検討した。
その結果、本発明者らは、粘着剤層の体積に対する金属フィラーの金属量、粘着剤層の厚み、及び、金属フィラーの粒子径のそれぞれ個別の値よりもむしろ、これらの値から特定の式により算出した値（本明細書中、「ａ値」という）と、電磁波シールド性との間に高い相関性があることを見出した。本発明者らは、「ａ値」を特定範囲に制御することにより、粘着剤層の断面からのノイズ放射を抑制し、優れた電磁波シールド性及び導電性を実現できることを見出し、本発明を完成させるに至った。 In the conductive pressure-sensitive adhesive tape having a conductive base material and a pressure-sensitive adhesive layer disposed on at least one surface of the conductive base material, the present inventors include an acrylic copolymer, a metal filler, and the pressure-sensitive adhesive layer. Then, the metal amount of the metal filler relative to the volume of the pressure-sensitive adhesive layer, the thickness of the pressure-sensitive adhesive layer, and the particle diameter of the metal filler were studied.
As a result, the inventors have determined that a specific formula is derived from these values rather than individual values of the amount of metal of the metal filler, the thickness of the pressure-sensitive adhesive layer, and the particle size of the metal filler relative to the volume of the pressure-sensitive adhesive layer. It was found that there is a high correlation between the value calculated by the above (referred to as “a value” in this specification) and the electromagnetic wave shielding property. The present inventors have found that by controlling the “a value” within a specific range, noise emission from the cross section of the pressure-sensitive adhesive layer can be suppressed, and excellent electromagnetic shielding properties and conductivity can be realized, and the present invention has been completed. I came to let you.

本発明の一実施態様である導電性粘着テープは、導電性基材と、上記導電性基材の少なくとも一方の面に配置された粘着剤層とを有する。
上記導電性基材は特に限定されず、例えば、金属箔、導電性樹脂基材等の箔状基材が挙げられる。なかでも、金属箔を含むことが好ましく、金属箔からなることがより好ましい。上記金属箔の材質は特に限定されず、例えば、ニッケル、銀、銅、アルミニウム等が挙げられ、また、これら金属の合金であってもよい。なかでも、抵抗値が安定であり、電磁波シールド性が各周波数帯で安定であることから、銀及び銅並びにこれらの合金が好ましく、銅がより好ましい。上記導電性基材は、単層であってもよく、複層であってもよいが、耐熱性及び防錆性を高める観点から複層であることが好ましい。本発明の一実施態様において、導電性基材が複層である場合、粘着剤層側に亜鉛及び／又はニッケルを含む金属層を有してもよい。 The electroconductive adhesive tape which is one embodiment of this invention has an electroconductive base material and the adhesive layer arrange | positioned at the at least one surface of the said electroconductive base material.
The conductive substrate is not particularly limited, and examples thereof include foil-shaped substrates such as metal foils and conductive resin substrates. Especially, it is preferable that metal foil is included, and it is more preferable to consist of metal foil. The material of the said metal foil is not specifically limited, For example, nickel, silver, copper, aluminum etc. are mentioned, Moreover, the alloy of these metals may be sufficient. Especially, since resistance value is stable and electromagnetic wave shielding property is stable in each frequency band, silver and copper, and these alloys are preferable, and copper is more preferable. The conductive substrate may be a single layer or a multilayer, but is preferably a multilayer from the viewpoint of improving heat resistance and rust prevention. In one embodiment of the present invention, when the conductive substrate is a multilayer, the pressure-sensitive adhesive layer may have a metal layer containing zinc and / or nickel.

上記導電性基材の厚みは特に限定されないが、好ましい下限は１μｍ、好ましい上限は１５０μｍである。上記導電性基材が１μｍ以上であれば、導電性粘着テープの強度が上がり、強い衝撃が加わった場合に破壊されることを抑制できる。上記導電性基材が１５０μｍ以下であれば、長期間が経過した場合の反発による導電性粘着テープの浮き剥がれを抑制できる。同様の観点から、上記導電性基材の厚みのより好ましい下限は５μｍ、より好ましい上限は４０μｍ、更に好ましい下限は９μｍ、更に好ましい上限は３５μｍ、更により好ましい下限は１０μｍ、更により好ましい上限は３０μｍである。 Although the thickness of the said electroconductive base material is not specifically limited, A preferable minimum is 1 micrometer and a preferable upper limit is 150 micrometers. If the said electroconductive base material is 1 micrometer or more, the intensity | strength of an electroconductive adhesive tape will rise and it can suppress that it is destroyed when a strong impact is added. If the said electroconductive base material is 150 micrometers or less, the floating peeling of the electroconductive adhesive tape by repulsion when a long time passes can be suppressed. From the same viewpoint, the more preferable lower limit of the thickness of the conductive substrate is 5 μm, the more preferable upper limit is 40 μm, the still more preferable lower limit is 9 μm, the still more preferable upper limit is 35 μm, the still more preferable lower limit is 10 μm, and the still more preferable upper limit is 30 μm. It is.

上記粘着剤層は、上記導電性基材の少なくとも一方の面に配置されていれば、上記導電性基材の片面に配置されていても両面に配置されていてもよい。上記粘着剤層が上記導電性基材の両面に配置されている場合、両面の粘着剤層は同じ組成であってもそれぞれ異なる組成であってもよく、少なくとも一方の粘着剤層が後述する範囲のａ値を有していればよい。 The pressure-sensitive adhesive layer may be disposed on one side or both sides of the conductive substrate as long as it is disposed on at least one surface of the conductive substrate. When the pressure-sensitive adhesive layer is disposed on both surfaces of the conductive substrate, the pressure-sensitive adhesive layers on both sides may be the same composition or different compositions, and at least one pressure-sensitive adhesive layer is a range described later. It is sufficient to have a value of

上記粘着剤層は、アクリル共重合体と、金属フィラーとを含有する。
上記アクリル共重合体は、ブチルアクリレート（ＢＡ）と２－エチルヘキシルアクリレート（２ＥＨＡ）とを含むモノマー混合物を共重合して得られた共重合体であることが好ましい。全モノマー混合物に占めるブチルアクリレートの含有量、及び、２－エチルヘキシルアクリレートの含有量は特に限定されないが、ブチルアクリレートの好ましい含有量は５０～９０重量％、２－エチルヘキシルアクリレートの好ましい含有量は１０～５０重量％である。 The pressure-sensitive adhesive layer contains an acrylic copolymer and a metal filler.
The acrylic copolymer is preferably a copolymer obtained by copolymerizing a monomer mixture containing butyl acrylate (BA) and 2-ethylhexyl acrylate (2EHA). The content of butyl acrylate and the content of 2-ethylhexyl acrylate in the total monomer mixture is not particularly limited, but the preferred content of butyl acrylate is 50 to 90% by weight, and the preferred content of 2-ethylhexyl acrylate is 10 to 50% by weight.

上記モノマー混合物は、必要に応じてブチルアクリレート及び２－エチルヘキシルアクリレート以外の共重合可能な他の重合性モノマーを含んでいてもよい。
上記共重合可能な他の重合性モノマーとして、例えば、アルキル基の炭素数が１～３の（メタ）アクリル酸アルキルエステル、アルキル基の炭素数が１３～１８の（メタ）アクリル酸アルキルエステル、官能性モノマーが挙げられる。これらの共重合可能な他の重合性モノマーは単独で用いてもよいし、２種以上を併用してもよい。 The monomer mixture may contain other copolymerizable monomers other than butyl acrylate and 2-ethylhexyl acrylate as necessary.
Examples of the other polymerizable monomer that can be copolymerized include, for example, (meth) acrylic acid alkyl esters having an alkyl group having 1 to 3 carbon atoms, (meth) acrylic acid alkyl esters having an alkyl group having 13 to 18 carbon atoms, Examples include functional monomers. These other polymerizable monomers capable of copolymerization may be used alone or in combination of two or more.

上記アルキル基の炭素数が１～３の（メタ）アクリル酸アルキルエステルとして、例えば、（メタ）アクリル酸メチル、（メタ）アクリル酸エチル、（メタ）アクリル酸ｎ－プロピル、（メタ）アクリル酸イソプロピル等が挙げられる。
上記アルキル基の炭素数が１３～１８の（メタ）アクリル酸アルキルエステルとして、例えば、メタクリル酸トリデシル、（メタ）アクリル酸ステアリル等が挙げられる。
上記官能性モノマーとして、例えば、（メタ）アクリル酸ヒドロキシアルキル、グリセリンジメタクリレート、（メタ）アクリル酸グリシジル、２－メタクリロイルオキシエチルイソシアネート、（メタ）アクリル酸、イタコン酸、無水マレイン酸、クロトン酸、マレイン酸、フマル酸等が挙げられる。 Examples of the (meth) acrylic acid alkyl ester having 1 to 3 carbon atoms in the alkyl group include, for example, methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, and (meth) acrylic acid. And isopropyl.
Examples of the (meth) acrylic acid alkyl ester having 13 to 18 carbon atoms in the alkyl group include tridecyl methacrylate and stearyl (meth) acrylate.
Examples of the functional monomer include hydroxyalkyl (meth) acrylate, glycerin dimethacrylate, glycidyl (meth) acrylate, 2-methacryloyloxyethyl isocyanate, (meth) acrylic acid, itaconic acid, maleic anhydride, crotonic acid, Maleic acid, fumaric acid, etc. are mentioned.

上記モノマー混合物は、必要に応じて、架橋性モノマーを０．１～１０重量％含有することが好ましい。上記モノマー混合物が架橋性モノマーを上記範囲で含有することで得られる導電性粘着テープの凝集力を高めることができると共に、金属フィラーによる微少な浮きを抑えて安定して電磁波シールド性及び導電性を発現することができる。上記架橋性モノマーとしては、例えば、カルボキシル基含有モノマー、水酸基含有モノマー、グリシジル基含有モノマー、メチロール基含有モノマー等が挙げられる。水酸基含有モノマーとしては、例えば、ヒドロキシエチル（メタ）アクリレート、ヒドロキシプロピル（メタ）アクリレート、４－ブチルヒドロキシ（メタ）アクリレート等が挙げられる。カルボキシル基含有モノマーとしては、例えば、アクリル酸、メタクリル酸、イタコン酸、無水マレイン酸、等が挙げられる。
本発明の好適な実施態様において、粘着テープの凝集力を高めると同時に電磁波シールド性及び導電性を高める観点から、上記モノマー混合物は、水酸基含有モノマー及びカルボキシル基含有モノマーを含むことが好ましい。また、上記モノマー混合物は、ヒドロキシエチル（メタ）アクリレート及び／又は４－ブチルヒドロキシ（メタ）アクリレート並びに（メタ）アクリル酸を併用することがより好ましい。また、粘着テープの凝集力を高めると同時に電磁波シールド性及び導電性を更に高める観点から、上記モノマー混合物中における上記架橋性モノマーの含有量は、より好ましくは０．５重量％以上、更に好ましくは１重量％以上、更により好ましくは２重量％以上であり、より好ましくは８重量％以下、更に好ましくは６重量％以下、更により好ましくは４重量％以下である。 The monomer mixture preferably contains 0.1 to 10% by weight of a crosslinkable monomer as required. The monomer mixture contains a crosslinkable monomer in the above range, and the cohesive strength of the conductive adhesive tape obtained can be enhanced, and the electromagnetic wave shielding property and conductivity can be stably suppressed by suppressing the slight floating caused by the metal filler. Can be expressed. Examples of the crosslinkable monomer include a carboxyl group-containing monomer, a hydroxyl group-containing monomer, a glycidyl group-containing monomer, and a methylol group-containing monomer. Examples of the hydroxyl group-containing monomer include hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, 4-butylhydroxy (meth) acrylate and the like. Examples of the carboxyl group-containing monomer include acrylic acid, methacrylic acid, itaconic acid, maleic anhydride, and the like.
In a preferred embodiment of the present invention, the monomer mixture preferably contains a hydroxyl group-containing monomer and a carboxyl group-containing monomer from the viewpoint of increasing the cohesive strength of the pressure-sensitive adhesive tape and at the same time enhancing the electromagnetic wave shielding properties and conductivity. The monomer mixture is more preferably used in combination with hydroxyethyl (meth) acrylate and / or 4-butylhydroxy (meth) acrylate and (meth) acrylic acid. In addition, from the viewpoint of increasing the cohesive force of the adhesive tape and at the same time further enhancing the electromagnetic wave shielding property and conductivity, the content of the crosslinkable monomer in the monomer mixture is more preferably 0.5% by weight or more, and still more preferably. 1% by weight or more, still more preferably 2% by weight or more, more preferably 8% by weight or less, still more preferably 6% by weight or less, and still more preferably 4% by weight or less.

上記モノマー混合物が架橋性モノマーとして水酸基含有モノマーを含有する場合、その含有量は、粘着テープの凝集力を高めると同時に電磁波シールド性及び導電性を更に高める観点から、より好ましくは０．１重量％以上、更に好ましくは０．１５重量％以上、更により好ましくは０．２重量％以上であり、より好ましくは３重量％以下、更に好ましくは２重量％以下、更により好ましくは１重量％以下である。 When the monomer mixture contains a hydroxyl group-containing monomer as a crosslinkable monomer, the content thereof is more preferably 0.1% by weight from the viewpoint of further enhancing the cohesive strength of the pressure-sensitive adhesive tape and at the same time further enhancing the electromagnetic shielding properties and conductivity. Or more, more preferably 0.15% by weight or more, still more preferably 0.2% by weight or more, more preferably 3% by weight or less, still more preferably 2% by weight or less, and even more preferably 1% by weight or less. is there.

上記モノマー混合物が架橋性モノマーとしてカルボキシル基含有モノマーを含有する場合、その含有量は、粘着テープの凝集力を高めると同時に電磁波シールド性及び導電性を更に高める観点から、より好ましくは１重量％以上、更に好ましくは１．５重量％以上、更により好ましくは２重量％以上であり、より好ましくは８重量％以下、更に好ましくは５重量％以下、更により好ましくは３重量％以下である。 When the monomer mixture contains a carboxyl group-containing monomer as a crosslinkable monomer, the content is more preferably 1% by weight or more from the viewpoint of further increasing the cohesive strength of the pressure-sensitive adhesive tape and at the same time further enhancing the electromagnetic shielding properties and conductivity. More preferably, it is 1.5% by weight or more, still more preferably 2% by weight or more, more preferably 8% by weight or less, still more preferably 5% by weight or less, and even more preferably 3% by weight or less.

上記モノマー混合物を共重合して上記アクリル共重合体を得るには、上記モノマー混合物を、重合開始剤の存在下にてラジカル反応させればよい。上記モノマー混合物をラジカル反応させる方法、即ち、重合方法としては、従来公知の方法が用いられ、例えば、溶液重合（沸点重合又は定温重合）、乳化重合、懸濁重合、塊状重合等が挙げられる。
上記重合開始剤は特に限定されず、例えば、有機過酸化物、アゾ化合物等が挙げられる。上記有機過酸化物として、例えば、１，１－ビス（ｔ－ヘキシルパーオキシ）－３，３，５－トリメチルシクロヘキサン、ｔ－ヘキシルパーオキシピバレート、ｔ－ブチルパーオキシピバレート、２，５－ジメチル－２，５－ビス（２－エチルヘキサノイルパーオキシ）ヘキサン、ｔ－ヘキシルパーオキシ－２－エチルヘキサノエート、ｔ－ブチルパーオキシ－２－エチルヘキサノエート、ｔ－ブチルパーオキシイソブチレート、ｔ－ブチルパーオキシ－３，５，５－トリメチルヘキサノエート、ｔ－ブチルパーオキシラウレート等が挙げられる。上記アゾ化合物として、例えば、アゾビスイソブチロニトリル、アゾビスシクロヘキサンカルボニトリル等が挙げられる。これらの重合開始剤は単独で用いてもよいし、２種以上を併用してもよい。 In order to copolymerize the monomer mixture to obtain the acrylic copolymer, the monomer mixture may be radically reacted in the presence of a polymerization initiator. As a method of radical reaction of the monomer mixture, that is, a polymerization method, a conventionally known method is used, and examples thereof include solution polymerization (boiling point polymerization or constant temperature polymerization), emulsion polymerization, suspension polymerization, bulk polymerization and the like.
The said polymerization initiator is not specifically limited, For example, an organic peroxide, an azo compound, etc. are mentioned. Examples of the organic peroxide include 1,1-bis (t-hexylperoxy) -3,3,5-trimethylcyclohexane, t-hexylperoxypivalate, t-butylperoxypivalate, 2,5 -Dimethyl-2,5-bis (2-ethylhexanoylperoxy) hexane, t-hexylperoxy-2-ethylhexanoate, t-butylperoxy-2-ethylhexanoate, t-butylperoxy Examples include isobutyrate, t-butylperoxy-3,5,5-trimethylhexanoate, and t-butylperoxylaurate. Examples of the azo compound include azobisisobutyronitrile and azobiscyclohexanecarbonitrile. These polymerization initiators may be used alone or in combination of two or more.

上記アクリル共重合体の重量平均分子量（Ｍｗ）は特に限定されないが、好ましい下限が４０万、好ましい上限が１６０万、より好ましい上限は１４０万、更に好ましい上限は１２０万である。上記重量平均分子量が４０万以上であれば、上記粘着剤層の凝集力が高くなり、導電性粘着テープの接着信頼性が向上する。上記重量平均分子量が１６０万以下であれば、上記粘着剤層が硬くなりすぎることなく充分な段差追従性及び粘着力を有し、導電性粘着テープの接着信頼性が向上する。導電性粘着テープの接着信頼性を更に向上させる観点から、上記重量平均分子量のより好ましい下限は５０万、更に好ましい下限は７０万である。
重量平均分子量を上記範囲に制御するためには、重合開始剤、重合温度等の重合条件を制御すればよい。
なお、重量平均分子量（Ｍｗ）とは、ＧＰＣ（Ｇｅｌ　Ｐｅｒｍｅａｔｉｏｎ　Ｃｈｒｏｍａｔｏｇｒａｐｈｙ：ゲルパーミエーションクロマトグラフィ）による標準ポリスチレン換算の重量平均分子量である。 The weight average molecular weight (Mw) of the acrylic copolymer is not particularly limited, but a preferred lower limit is 400,000, a preferred upper limit is 1.6 million, a more preferred upper limit is 1.4 million, and a more preferred upper limit is 1,200,000. If the said weight average molecular weight is 400,000 or more, the cohesion force of the said adhesive layer will become high and the adhesive reliability of an electroconductive adhesive tape will improve. If the said weight average molecular weight is 1.6 million or less, the said adhesive layer has sufficient level | step difference followability and adhesive force, without becoming too hard, and the adhesive reliability of an electroconductive adhesive tape improves. From the viewpoint of further improving the adhesion reliability of the conductive pressure-sensitive adhesive tape, the more preferable lower limit of the weight average molecular weight is 500,000, and the more preferable lower limit is 700,000.
In order to control the weight average molecular weight within the above range, the polymerization conditions such as the polymerization initiator and the polymerization temperature may be controlled.
In addition, a weight average molecular weight (Mw) is a weight average molecular weight of standard polystyrene conversion by GPC (Gel Permeation Chromatography: gel permeation chromatography).

上記金属フィラーは、金属のみからなるフィラーであってもよいし、金属以外のコア（例えば、樹脂粒子）に金属被覆が施されたフィラーであってもよい。
上記金属フィラーにおける金属として、例えば、ニッケル、銀、銅、金、アルミニウム、鉄、スズ合金、及びチタン並びにこれらの合金等が挙げられる。なかでも、銅、銀、及びニッケル並びにこれらの合金が好ましい。更に、銅、銀は不動態等を生じて導電性が低下することがあるため、ニッケルがより好ましい。 The metal filler may be a filler made of only metal, or may be a filler in which a metal coating is applied to a core (for example, resin particles) other than metal.
Examples of the metal in the metal filler include nickel, silver, copper, gold, aluminum, iron, tin alloy, titanium, and alloys thereof. Of these, copper, silver, nickel, and alloys thereof are preferable. Furthermore, since copper and silver may cause passivation or the like and the conductivity may be lowered, nickel is more preferable.

上記金属フィラーの形状は特に限定されず、例えば、球状、楕円状、針状、角状、樹枝状、片状、不規則形状、涙滴状、粒状等が挙げられる。なかでも、上記アクリル共重合体への分散性と抵抗値安定性との観点から、球状、楕円状、針状又は粒状が好ましい。 The shape of the metal filler is not particularly limited, and examples thereof include a spherical shape, an elliptical shape, a needle shape, a square shape, a dendritic shape, a piece shape, an irregular shape, a teardrop shape, and a granular shape. Among these, from the viewpoint of dispersibility in the acrylic copolymer and stability of resistance value, a spherical shape, an elliptical shape, a needle shape, or a granular shape is preferable.

上記粘着剤層は、下記式（１）により算出したａ値が０以上である。
ａ値＝（２５×Ｍ）＋｛２２×（ｄ７０／Ｄ）｝－３×（ｄ７０－ｄ４０）－１８　　（１）
Ｍ：上記粘着剤層の体積に対する上記金属フィラーの金属量（体積％）
Ｄ：上記粘着剤層の厚み（μｍ）
ｄ４０：体積基準の累積分布が４０％となるときの上記金属フィラーの粒子径（μｍ）
ｄ７０：体積基準の累積分布が７０％となるときの上記金属フィラーの粒子径（μｍ） The pressure-sensitive adhesive layer has an a value calculated by the following formula (1) of 0 or more.
a value = (25 × M) + {22 × (d70 / D)} − 3 × (d70−d40) −18 (1)
M: Metal content of the metal filler (volume%) relative to the volume of the pressure-sensitive adhesive layer
D: Thickness (μm) of the pressure-sensitive adhesive layer
d40: Particle diameter (μm) of the metal filler when the volume-based cumulative distribution is 40%
d70: Particle diameter (μm) of the metal filler when the volume-based cumulative distribution is 70%

上記ａ値が０以上であれば、上記粘着剤層の断面からのノイズ放射が抑制され、導電性粘着テープの電磁波シールド性及び導電性が向上する。電磁波シールド性の更なる向上の観点から、上記ａ値は好ましくは５以上、より好ましくは７以上、更に好ましくは９以上、更により好ましくは１０以上、特に好ましくは１２以上、とりわけ好ましくは１３以上、非常に好ましくは１４以上である。
上記ａ値の上限は特に限定されないが、導電性粘着テープの電磁波シールド性及び導電性と、粘着性能のバランスとの観点から、好ましい上限は２００、より好ましい上限は１００、更に好ましい上限は５０、更により好ましい上限は３０である。
なお、「ａ値」は、実施例及び比較例における粘着剤層の体積に対する金属フィラーの金属量、粘着剤層の厚み、体積基準の累積分布が４０％となるときの金属フィラーの粒子径、及び、体積基準の累積分布が７０％となるときの金属フィラーの粒子径と、電磁波シールド性との間の相関性から回帰分析により導かれたものである。この際、電磁波シールド性の評価において１ＧＨｚでの測定結果が６５ｄＢ以上であった場合に充分な電磁波シールド性を有すると判断した。回帰分析としては、例えば、線形回帰、非線形回帰等の通常行われる方法を採用することができる。 If said a value is 0 or more, the noise radiation from the cross section of the said adhesive layer will be suppressed, and the electromagnetic wave shielding property and electroconductivity of a conductive adhesive tape will improve. From the viewpoint of further improving electromagnetic shielding properties, the a value is preferably 5 or more, more preferably 7 or more, still more preferably 9 or more, still more preferably 10 or more, particularly preferably 12 or more, and particularly preferably 13 or more. Very preferably 14 or more.
Although the upper limit of the a value is not particularly limited, the preferable upper limit is 200, the more preferable upper limit is 100, and the still more preferable upper limit is 50, from the viewpoint of the electromagnetic shielding property and conductivity of the conductive adhesive tape and the balance of the adhesive performance. An even more preferred upper limit is 30.
The “a value” is the metal amount of the metal filler relative to the volume of the pressure-sensitive adhesive layer in Examples and Comparative Examples, the thickness of the pressure-sensitive adhesive layer, the particle diameter of the metal filler when the volume-based cumulative distribution is 40%, And it is derived by regression analysis from the correlation between the particle diameter of the metal filler when the volume-based cumulative distribution is 70% and the electromagnetic shielding properties. At this time, when the measurement result at 1 GHz was 65 dB or more in the evaluation of the electromagnetic wave shielding property, it was determined that the electromagnetic wave shielding property was sufficient. As the regression analysis, for example, a commonly performed method such as linear regression or nonlinear regression can be employed.

上記ａ値を上記範囲に制御する方法として、上記粘着剤層の体積に対する上記金属フィラーの金属量（Ｍ）を増やす方法、上記粘着剤層の厚み（Ｄ）を薄くする方法、上記粘着剤層の厚み（Ｄ）に対する体積基準の累積分布が７０％となるときの上記金属フィラーの粒子径（ｄ７０）の比（ｄ７０／Ｄ）を大きくする方法が好ましい。また、体積基準の累積分布が７０％となるときの上記金属フィラーの粒子径（ｄ７０）と、体積基準の累積分布が４０％となるときの上記金属フィラーの粒子径（ｄ４０）との差（ｄ７０－ｄ４０）を小さくする（即ち、粒度分布をシャープにする）方法も好ましい。これらの方法は単独で用いてもよいし、２種以上を併用してもよい。 As a method of controlling the a value within the above range, a method of increasing the metal amount (M) of the metal filler with respect to the volume of the pressure-sensitive adhesive layer, a method of reducing the thickness (D) of the pressure-sensitive adhesive layer, and the pressure-sensitive adhesive layer A method of increasing the ratio (d70 / D) of the particle diameter (d70) of the metal filler when the volume-based cumulative distribution with respect to the thickness (D) of the metal filler becomes 70% is preferable. Further, the difference between the particle diameter (d70) of the metal filler when the volume-based cumulative distribution is 70% and the particle diameter (d40) of the metal filler when the volume-based cumulative distribution is 40% ( A method of reducing d70-d40) (that is, sharpening the particle size distribution) is also preferable. These methods may be used alone or in combination of two or more.

上記粘着剤層の体積に対する上記金属フィラーの金属量（Ｍ）の好ましい下限は０．００１体積％、好ましい上限は１０体積％である。上記金属量が０．００１体積％以上であれば、上記粘着剤層において導電パスが充分に形成され、導電性粘着テープの電磁波シールド性及び導電性が向上する。上記金属量が１０体積％以下であれば、上記金属フィラーの界面の接触抵抗が影響することによる抵抗値の上昇を抑制することができる。導電性粘着テープの電磁波シールド性及び導電性を更に向上させる観点から、上記金属量のより好ましい下限は０．０１体積％であり、抵抗値の上昇を更に抑制させる観点から、上記金属量のより好ましい上限は３．５体積％である。 A preferable lower limit of the metal amount (M) of the metal filler with respect to the volume of the pressure-sensitive adhesive layer is 0.001% by volume, and a preferable upper limit is 10% by volume. When the metal content is 0.001% by volume or more, a conductive path is sufficiently formed in the pressure-sensitive adhesive layer, and the electromagnetic wave shielding property and conductivity of the conductive pressure-sensitive adhesive tape are improved. When the amount of the metal is 10% by volume or less, an increase in the resistance value due to the influence of the contact resistance at the interface of the metal filler can be suppressed. From the viewpoint of further improving the electromagnetic wave shielding properties and conductivity of the conductive pressure-sensitive adhesive tape, a more preferable lower limit of the metal amount is 0.01% by volume, and from the viewpoint of further suppressing an increase in resistance value, A preferred upper limit is 3.5% by volume.

上記粘着剤層の厚み（Ｄ）の好ましい下限は１μｍ、好ましい上限は５０μｍである。上記厚みが１μｍ以上であれば、上記粘着剤層が充分な粘着力を有し、導電性粘着テープの接着信頼性が向上する。上記厚みが５０μｍ以下であれば、上記粘着剤層の断面からのノイズ放射が抑制され、導電性粘着テープの電磁波シールド性及び導電性が向上する。上記粘着剤層の厚みのより好ましい下限は３μｍ、より好ましい上限は３０μｍ、更に好ましい下限は４μｍ、更に好ましい上限は２０μｍ、更により好ましい下限は５μｍ、更により好ましい上限は１５μｍ、特に好ましい上限は１４μｍである。 The minimum with preferable thickness (D) of the said adhesive layer is 1 micrometer, and a preferable upper limit is 50 micrometers. If the said thickness is 1 micrometer or more, the said adhesive layer has sufficient adhesive force, and the adhesive reliability of an electroconductive adhesive tape will improve. If the said thickness is 50 micrometers or less, the noise radiation from the cross section of the said adhesive layer will be suppressed, and the electromagnetic wave shielding property and electroconductivity of a conductive adhesive tape will improve. The more preferable lower limit of the thickness of the pressure-sensitive adhesive layer is 3 μm, the more preferable upper limit is 30 μm, the still more preferable lower limit is 4 μm, the still more preferable upper limit is 20 μm, the still more preferable lower limit is 5 μm, the still more preferable upper limit is 15 μm, and the particularly preferable upper limit is 14 μm. It is.

上記粘着剤層の厚み（Ｄ）に対する体積基準の累積分布が７０％となるときの上記金属フィラーの粒子径（ｄ７０）の比（ｄ７０／Ｄ）の好ましい下限は０．６、好ましい上限は５．０である。上記比（ｄ７０／Ｄ）が０．６以上であれば、上記粘着剤層からの上記金属フィラーのはみ出しが大きくなり、導電性粘着テープの電磁波シールド性及び導電性が向上する。上記比（ｄ７０／Ｄ）が５．０以下であれば、上記粘着剤層からの上記金属フィラーの過度のはみ出しが抑制され、充分な粘着性能を維持することができる。導電性粘着テープの電磁波シールド性及び導電性を更に向上させる観点から、上記比（ｄ７０／Ｄ）のより好ましい下限は０．７、更に好ましい下限は０．７５、更により好ましい下限は０．８、特に好ましい下限は０．８５、とりわけ好ましい下限は０．９、非常に好ましい下限は１、最も好ましい下限は１．１である。また、粘着性能の維持の観点から、上記比（ｄ７０／Ｄ）のより好ましい上限は５．０、更に好ましい上限は４．０、更により好ましい上限は３．５、特に好ましい上限は３．３、とりわけ好ましい上限は３．２、非常に好ましい上限は３．１、最も好ましい上限は３である。 The preferable lower limit of the ratio (d70 / D) of the particle diameter (d70) of the metal filler when the volume-based cumulative distribution with respect to the thickness (D) of the pressure-sensitive adhesive layer is 70% is 0.6, and the preferable upper limit is 5 .0. When the ratio (d70 / D) is 0.6 or more, the metal filler protrudes from the pressure-sensitive adhesive layer, and the electromagnetic wave shielding property and conductivity of the conductive pressure-sensitive adhesive tape are improved. When the ratio (d70 / D) is 5.0 or less, excessive protrusion of the metal filler from the pressure-sensitive adhesive layer is suppressed, and sufficient pressure-sensitive adhesive performance can be maintained. From the viewpoint of further improving the electromagnetic wave shielding property and conductivity of the conductive adhesive tape, the more preferable lower limit of the ratio (d70 / D) is 0.7, the still more preferable lower limit is 0.75, and the still more preferable lower limit is 0.8. A particularly preferred lower limit is 0.85, a particularly preferred lower limit is 0.9, a very preferred lower limit is 1, and a most preferred lower limit is 1.1. Further, from the viewpoint of maintaining the adhesive performance, the more preferable upper limit of the ratio (d70 / D) is 5.0, the still more preferable upper limit is 4.0, the still more preferable upper limit is 3.5, and the particularly preferable upper limit is 3.3. In particular, the preferred upper limit is 3.2, the very preferred upper limit is 3.1, and the most preferred upper limit is 3.

体積基準の累積分布が７０％となるときの上記金属フィラーの粒子径（ｄ７０）と、体積基準の累積分布が４０％となるときの上記金属フィラーの粒子径（ｄ４０）との差（ｄ７０－ｄ４０）の好ましい下限は０．０１μｍ、好ましい上限は４０μｍである。上記差（ｄ７０－ｄ４０）が０．０１μｍ以上であれば、上記比（ｄ７０／Ｄ）が小さい値でも高い電磁波シールド性を発揮できる。上記差（ｄ７０－ｄ４０）が４０μｍ以下であれば、粒度分布がシャープとなり、導電性粘着テープの電磁波シールド性及び導電性が安定して得られる。高い電磁波シールド性を発揮できる観点から、上記差（ｄ７０－ｄ４０）のより好ましい下限は１μｍ、より好ましい上限は３０μｍである。 The difference (d70−) between the particle diameter (d70) of the metal filler when the volume-based cumulative distribution is 70% and the particle diameter (d40) of the metal filler when the volume-based cumulative distribution is 40%. The preferable lower limit of d40) is 0.01 μm, and the preferable upper limit is 40 μm. When the difference (d70−d40) is 0.01 μm or more, high electromagnetic shielding properties can be exhibited even when the ratio (d70 / D) is small. When the difference (d70−d40) is 40 μm or less, the particle size distribution becomes sharp, and the electromagnetic wave shielding property and conductivity of the conductive adhesive tape can be obtained stably. From the viewpoint of exhibiting high electromagnetic wave shielding properties, a more preferable lower limit of the difference (d70−d40) is 1 μm, and a more preferable upper limit is 30 μm.

体積基準の累積分布が７０％となるときの上記金属フィラーの粒子径（ｄ７０）は、上記粘着剤層の厚み（Ｄ）によらず上記ａ値を上記範囲に制御しやすいことから、好ましい下限は４．０μｍ、好ましい上限は５０μｍであり、より好ましい下限は６．０μｍ、より好ましい上限は４０μｍである。
体積基準の累積分布が４０％となるときの上記金属フィラーの粒子径（ｄ４０）は、好ましい下限は２．０μｍ、好ましい上限は４０μｍであり、より好ましい下限は４．０μｍ、より好ましい上限は３０μｍである。
なお、金属フィラーの粒子径（ｄ７０及びｄ４０）は、レーザー回折装置（例えば、島津製作所社製のＳＡＬＤ－３０００）で粒度分布を測定して得ることができる。
なお、粘着剤層中の金属フィラーの粒子径は、金属フィラーを含む粘着剤層を不活性ガス下で加熱し、金属フィラー以外の成分のみを熱分解させ、金属フィラーのみを採取しレーザー回折装置で粒度分布を測定することができる。 The particle size (d70) of the metal filler when the volume-based cumulative distribution is 70% is preferable because the a value can be easily controlled within the above range regardless of the thickness (D) of the pressure-sensitive adhesive layer. Is 4.0 μm, the preferred upper limit is 50 μm, the more preferred lower limit is 6.0 μm, and the more preferred upper limit is 40 μm.
The particle diameter (d40) of the metal filler when the cumulative distribution on the volume basis is 40% is preferably a lower limit of 2.0 μm, a preferable upper limit of 40 μm, a more preferable lower limit of 4.0 μm, and a more preferable upper limit of 30 μm. It is.
The particle size (d70 and d40) of the metal filler can be obtained by measuring the particle size distribution with a laser diffractometer (for example, SALD-3000 manufactured by Shimadzu Corporation).
The particle size of the metal filler in the pressure-sensitive adhesive layer is determined by heating the pressure-sensitive adhesive layer containing the metal filler under an inert gas, pyrolyzing only the components other than the metal filler, collecting only the metal filler, and laser diffractometer. The particle size distribution can be measured.

上記粘着剤層は、粘着付与樹脂を含有することが好ましい。
上記粘着付与樹脂として、例えば、ロジンエステル系樹脂、水添ロジン系樹脂、テルペン系樹脂、テルペンフェノール系樹脂、クマロンインデン系樹脂、脂環族飽和炭化水素系樹脂、Ｃ５系石油樹脂、Ｃ９系石油樹脂、Ｃ５－Ｃ９共重合系石油樹脂等が挙げられる。これらの粘着付与樹脂は単独で用いてもよいし、２種以上を併用してもよい。 The pressure-sensitive adhesive layer preferably contains a tackifier resin.
Examples of the tackifier resins include rosin ester resins, hydrogenated rosin resins, terpene resins, terpene phenol resins, coumarone indene resins, alicyclic saturated hydrocarbon resins, C5 petroleum resins, and C9 resins. Examples include petroleum resins and C5-C9 copolymer petroleum resins. These tackifying resins may be used alone or in combination of two or more.

上記粘着付与樹脂は、接着性向上及び上記金属フィラーの分散性向上の観点から、高極性であることが好ましく、その水酸基価の好ましい下限は２０、好ましい上限は２００であり、より好ましい下限は３０、より好ましい上限は１５０である。 The tackifier resin is preferably highly polar from the viewpoint of improving adhesiveness and dispersibility of the metal filler. The preferred lower limit of the hydroxyl value is 20, the preferred upper limit is 200, and the more preferred lower limit is 30. A more preferred upper limit is 150.

上記粘着付与樹脂の含有量は特に限定されないが、上記アクリル共重合体１００重量部に対する好ましい下限は５重量部、好ましい上限は４０重量部である。上記含有量が５重量部以上であれば、上記粘着剤層が充分な粘着力を有し、導電性粘着テープの接着信頼性が向上する。上記含有量が４０重量部以下であれば、上記粘着剤層が硬くなりすぎることなく充分な段差追従性及び粘着力を有し、導電性粘着テープの接着信頼性が向上する。同様の観点から、上記含有量のより好ましい下限は１０重量部、より好ましい下限は３０重量部である。 Although content of the said tackifying resin is not specifically limited, The preferable minimum with respect to 100 weight part of said acrylic copolymers is 5 weight part, and a preferable upper limit is 40 weight part. If the said content is 5 weight part or more, the said adhesive layer has sufficient adhesive force, and the adhesive reliability of an electroconductive adhesive tape will improve. When the content is 40 parts by weight or less, the pressure-sensitive adhesive layer has sufficient step following ability and adhesive force without becoming too hard, and the adhesive reliability of the conductive pressure-sensitive adhesive tape is improved. From the same viewpoint, the more preferable lower limit of the content is 10 parts by weight, and the more preferable lower limit is 30 parts by weight.

上記粘着剤層は、架橋剤が添加されることにより上記粘着剤層を構成する樹脂（上記アクリル共重合体及び／又は上記粘着付与樹脂）の主鎖間に架橋構造が形成されていることが好ましい。
上記架橋剤は特に限定されず、例えば、イソシアネート系架橋剤、アジリジン系架橋剤、エポキシ系架橋剤、金属キレート型架橋剤等が挙げられる。なかでも、イソシアネート系架橋剤が好ましい。上記粘着剤層にイソシアネート系架橋剤が添加されることで、イソシアネート系架橋剤のイソシアネート基と上記粘着剤層を構成する樹脂中のアルコール性水酸基とが反応して、上記粘着剤層の架橋が緩くなる。従って、上記粘着剤層は断続的に加わる剥離応力を分散させることができるため、導電性粘着テープの接着信頼性が向上する。
上記架橋剤の添加量は、上記アクリル共重合体１００重量部に対して０．０１～１０重量部が好ましく、０．１～３重量部がより好ましい。 In the pressure-sensitive adhesive layer, a crosslinking structure may be formed between main chains of the resin (the acrylic copolymer and / or the tackifying resin) constituting the pressure-sensitive adhesive layer by adding a crosslinking agent. preferable.
The said crosslinking agent is not specifically limited, For example, an isocyanate type crosslinking agent, an aziridine type crosslinking agent, an epoxy-type crosslinking agent, a metal chelate type crosslinking agent etc. are mentioned. Of these, isocyanate-based crosslinking agents are preferred. By adding an isocyanate-based crosslinking agent to the pressure-sensitive adhesive layer, the isocyanate group of the isocyanate-based crosslinking agent reacts with the alcoholic hydroxyl group in the resin constituting the pressure-sensitive adhesive layer, thereby cross-linking the pressure-sensitive adhesive layer. It becomes loose. Therefore, since the said adhesive layer can disperse the peeling stress added intermittently, the adhesive reliability of an electroconductive adhesive tape improves.
The addition amount of the crosslinking agent is preferably 0.01 to 10 parts by weight and more preferably 0.1 to 3 parts by weight with respect to 100 parts by weight of the acrylic copolymer.

上記粘着剤層は、必要に応じて、可塑剤、乳化剤、軟化剤、充填剤、顔料、染料等の添加剤、ロジン系樹脂等のその他の樹脂等を含有していてもよい。 The pressure-sensitive adhesive layer may contain plasticizers, emulsifiers, softeners, fillers, additives such as pigments and dyes, and other resins such as rosin resins, if necessary.

上記粘着剤層の架橋度は特に限定されないが、好ましい下限が２０重量％、好ましい上限が４５重量％である。上記架橋度が２０重量％以上であれば、上記粘着剤層の凝集力が高くなり、導電性粘着テープの接着信頼性が向上する。上記架橋度が４５重量％以下であれば、上記粘着剤層が硬くなりすぎることなく充分な段差追従性及び粘着力を有し、導電性粘着テープの接着信頼性が向上する。導電性粘着テープの接着信頼性の更なる向上の観点から、上記架橋度のより好ましい下限は２５重量％、より好ましい上限は４０重量％であり、更に好ましい下限は３０重量％、更に好ましい上限は３５重量％である。
なお、粘着剤層の架橋度は、粘着剤層をＷ１（ｇ）採取し、この粘着剤層を酢酸エチル中に２３℃にて２４時間浸漬して不溶解分を２００メッシュの金網で濾過し、金網上の残渣を真空乾燥して乾燥残渣の重量Ｗ２（ｇ）を測定し、下記式（２）により算出する。
架橋度（重量％）＝１００×Ｗ２／Ｗ１　　　　（２） The degree of crosslinking of the pressure-sensitive adhesive layer is not particularly limited, but a preferred lower limit is 20% by weight and a preferred upper limit is 45% by weight. If the said crosslinking degree is 20 weight% or more, the cohesion force of the said adhesive layer will become high and the adhesive reliability of an electroconductive adhesive tape will improve. If the said crosslinking degree is 45 weight% or less, the said adhesive layer has sufficient level | step difference followability and adhesive force, without becoming too hard, and the adhesive reliability of an electroconductive adhesive tape improves. From the viewpoint of further improving the adhesion reliability of the conductive pressure-sensitive adhesive tape, the more preferred lower limit of the degree of crosslinking is 25% by weight, the more preferred upper limit is 40% by weight, the still more preferred lower limit is 30% by weight, and the more preferred upper limit is 35% by weight.
The degree of cross-linking of the pressure-sensitive adhesive layer was determined by collecting W1 (g) of the pressure-sensitive adhesive layer, immersing this pressure-sensitive adhesive layer in ethyl acetate at 23 ° C. for 24 hours, and filtering the insoluble matter with a 200-mesh wire mesh. The residue on the wire net is vacuum-dried, and the weight W2 (g) of the dry residue is measured, and calculated by the following formula (2).
Crosslinking degree (% by weight) = 100 × W2 / W1 (2)

本発明の一実施態様である導電性粘着テープの総厚みは特に限定されないが、好ましい下限は２μｍ、好ましい上限は２００μｍである。上記総厚みが上記範囲内であれば、導電性粘着テープの取り扱い性が向上する。上記総厚みのより好ましい下限は１０μｍ、より好ましい上限は５０μｍである。 Although the total thickness of the electroconductive adhesive tape which is one embodiment of this invention is not specifically limited, A preferable minimum is 2 micrometers and a preferable upper limit is 200 micrometers. If the said total thickness is in the said range, the handleability of an electroconductive adhesive tape will improve. The minimum with said more preferable total thickness is 10 micrometers, and a more preferable upper limit is 50 micrometers.

本発明の一実施態様である導電性粘着テープの製造方法として、例えば、以下のような方法が挙げられる。まず、アクリル共重合体、金属フィラー、必要に応じて粘着付与樹脂、架橋剤等に溶剤を加えて粘着剤ａの溶液を作製して、この粘着剤ａの溶液を導電性基材の表面に塗布し、溶液中の溶剤を完全に乾燥除去して粘着剤層ａを形成する。次に、形成された粘着剤層ａの上に離型フィルムをその離型処理面が粘着剤層ａに対向した状態に重ね合わせる。
次いで、上記離型フィルムとは別の離型フィルムを用意し、この離型フィルムの離型処理面に粘着剤ｂの溶液を塗布し、溶液中の溶剤を完全に乾燥除去することにより、離型フィルムの表面に粘着剤層ｂが形成された積層フィルムを作製する。得られた積層フィルムを粘着剤層ａが形成された導電性基材の裏面に、粘着剤層ｂが導電性基材の裏面に対向した状態に重ね合わせて積層体を作製する。そして、上記積層体をゴムローラ等によって加圧することによって、導電性基材の両面に粘着剤層を有し、かつ、粘着剤層の表面が離型フィルムで覆われた導電性粘着テープを得ることができる。 As a manufacturing method of the electroconductive adhesive tape which is one embodiment of this invention, the following methods are mentioned, for example. First, a solvent is added to an acrylic copolymer, a metal filler, a tackifier resin, a cross-linking agent, etc. as necessary to prepare a solution of the adhesive a, and the solution of the adhesive a is applied to the surface of the conductive substrate. The adhesive layer a is formed by applying and completely removing the solvent in the solution by drying. Next, the release film is superimposed on the formed pressure-sensitive adhesive layer a so that the release treatment surface faces the pressure-sensitive adhesive layer a.
Next, a release film different from the above release film is prepared, a solution of the adhesive b is applied to the release treatment surface of the release film, and the solvent in the solution is completely removed by drying, thereby releasing the release film. A laminated film in which the pressure-sensitive adhesive layer b is formed on the surface of the mold film is produced. The obtained laminated film is laminated on the back surface of the conductive base material on which the pressure-sensitive adhesive layer a is formed, and the pressure-sensitive adhesive layer b is superimposed on the back surface of the conductive base material to produce a laminate. And by pressing the said laminated body with a rubber roller etc., the conductive adhesive tape which has an adhesive layer on both surfaces of an electroconductive base material, and the surface of the adhesive layer was covered with the release film is obtained. Can do.

また、同様の要領で積層フィルムを２組作製し、これらの積層フィルムを導電性基材の両面のそれぞれに、積層フィルムの粘着剤層を導電性基材に対向させた状態に重ね合わせて積層体を作製し、この積層体をゴムローラ等によって加圧してもよい。これにより、導電性基材の両面に粘着剤層を有し、かつ、粘着剤層の表面が離型フィルムで覆われた導電性粘着テープを得てもよい。 In addition, two sets of laminated films are produced in the same manner, and these laminated films are laminated on both sides of the conductive base material with the adhesive layer of the laminated film facing the conductive base material. A laminated body may be produced and the laminated body may be pressed by a rubber roller or the like. Thereby, you may obtain the electroconductive adhesive tape which has an adhesive layer on both surfaces of an electroconductive base material, and the surface of the adhesive layer was covered with the release film.

本発明の一実施態様である導電性粘着テープの用途は特に限定されないが、電磁波シールド性及び導電性に優れることから、電子機器を構成する電子基板部品において、電子部品（例えばＣＰＵやコネクタ等）を覆うために用いられることが好ましく、電磁波シールド材として用いることが好ましい。
このようなＣＰＵカバー（シールドキャップ）用途における上記導電性粘着テープの形状は特に限定されず、例えば、長方形、額縁状、円形、楕円形、ドーナツ型等が挙げられる。その際の本発明の一実施態様である導電性粘着テープの貼付面積は特に限定されないが、１００００ｍｍ２以下であることが好ましい。 The use of the conductive pressure-sensitive adhesive tape according to one embodiment of the present invention is not particularly limited, but since it is excellent in electromagnetic shielding properties and conductivity, in an electronic board component constituting an electronic device, an electronic component (for example, a CPU or a connector). It is preferable to use it as an electromagnetic shielding material.
The shape of the conductive adhesive tape in such a CPU cover (shield cap) application is not particularly limited, and examples thereof include a rectangle, a frame shape, a circle, an ellipse, and a donut shape. In that case, the sticking area of the conductive adhesive tape which is one embodiment of the present invention is not particularly limited, but is preferably 10,000 mm 2 or less.

本発明によれば、電磁波シールド性及び導電性に優れた導電性粘着テープを提供することができる。 ADVANTAGE OF THE INVENTION According to this invention, the electroconductive adhesive tape excellent in electromagnetic wave shielding property and electroconductivity can be provided.

以下に実施例を挙げて本発明を更に詳しく説明するが、本発明はこれら実施例のみに限定されない。 EXAMPLES The present invention will be described in more detail with reference to examples below, but the present invention is not limited to these examples.

（実施例１）
（アクリル共重合体含有溶液（ａ）の調製）
反応容器内に、重合溶媒として酢酸エチルを加え、窒素でバブリングした後、窒素を流入しながら反応容器を加熱して還流を開始した。続いて、重合開始剤としてアゾビスイソブチロニトリル０．１重量部を酢酸エチルで１０倍希釈した重合開始剤溶液を反応容器内に投入した。続いて、２－エチルヘキシルアクリレート（２－ＥＨＡ）３０重量部、ブチルアクリレート（ＢＡ）６０重量部、シクロヘキシルメタクリレート（ＣＨＭＡ）６．７重量部、アクリル酸（ＡＡＣ）３重量部、４－ヒドロキシブチルアクリレート（４－ＨＢＡ）０．３重量部を２時間かけて滴下添加した。滴下終了後、重合開始剤としてアゾビスイソブチロニトリル０．１重量部を酢酸エチルで１０倍希釈した重合開始剤溶液を反応容器内に再度投入し、４時間重合反応を行い、アクリル共重合体含有溶液（ａ）（アクリル共重合体の重量平均分子量（Ｍｗ）：１２０万）を得た。 (Example 1)
(Preparation of acrylic copolymer-containing solution (a))
Ethyl acetate was added as a polymerization solvent in the reaction vessel, and after bubbling with nitrogen, the reaction vessel was heated while flowing nitrogen and refluxing was started. Subsequently, a polymerization initiator solution in which 0.1 part by weight of azobisisobutyronitrile as a polymerization initiator was diluted 10 times with ethyl acetate was charged into the reaction vessel. Subsequently, 2-ethylhexyl acrylate (2-EHA) 30 parts by weight, butyl acrylate (BA) 60 parts by weight, cyclohexyl methacrylate (CHMA) 6.7 parts by weight, acrylic acid (AAC) 3 parts by weight, 4-hydroxybutyl acrylate 0.3 parts by weight of (4-HBA) was added dropwise over 2 hours. After completion of the dropwise addition, a polymerization initiator solution obtained by diluting 0.1 part by weight of azobisisobutyronitrile 10 times with ethyl acetate as a polymerization initiator was charged again into the reaction vessel, and the polymerization reaction was performed for 4 hours. A coalescence-containing solution (a) (weight average molecular weight (Mw) of acrylic copolymer: 1,200,000) was obtained.

（導電性粘着テープの調製）
得られたアクリル共重合体含有溶液（ａ）中の、アクリル共重合体１００重量部に対して、金属フィラーとしてニッケル粒子（球状、ｄ４０＝８．５μｍ、ｄ７０＝１７．７μｍ、比重８．９１ｇ／ｃｍ３）を添加し、攪拌混合した。更に、粘着付与樹脂としてテルペン系樹脂（水酸基価１３０、ヤスハラケミカル社製、Ｇ－１５０）１５重量部、架橋剤としてイソシアネート系架橋剤（東ソー社製、コロネートＬ）１重量部、溶剤として酢酸エチル５０重量部を攪拌混合し、粘着剤溶液を調製した。
厚み２５μｍのＰＥＴセパレーターを用意し、このセパレーターの離型処理面に粘着剤溶液を塗布し、１１０℃で３分間乾燥させることにより、粘着剤層を形成した。この粘着剤層を厚み１８μｍの銅箔と貼り合わせることで、導電性粘着テープを得た。なお、形成される粘着剤層の体積に対して金属フィラーの金属量が１．１０体積％となるように、金属フィラーの配合量を制御した。得られた粘着剤層について、上述した式（１）によりａ値を算出した。 (Preparation of conductive adhesive tape)
Nickel particles (spherical, d40 = 8.5 μm, d70 = 17.7 μm, specific gravity 8.91 g) as a metal filler with respect to 100 parts by weight of the acrylic copolymer in the obtained acrylic copolymer-containing solution (a) / Cm 3 ) was added and mixed with stirring. Furthermore, 15 parts by weight of a terpene resin (hydroxyl value 130, manufactured by Yasuhara Chemical Co., Ltd., G-150) as a tackifier resin, 1 part by weight of an isocyanate crosslinker (manufactured by Tosoh Corporation, Coronate L), and 50% of ethyl acetate as a solvent. A weight part was stirred and mixed to prepare an adhesive solution.
A PET separator having a thickness of 25 μm was prepared, and the pressure-sensitive adhesive solution was applied to the release-treated surface of the separator and dried at 110 ° C. for 3 minutes to form a pressure-sensitive adhesive layer. By bonding this pressure-sensitive adhesive layer to a copper foil having a thickness of 18 μm, a conductive pressure-sensitive adhesive tape was obtained. In addition, the compounding quantity of the metal filler was controlled so that the metal content of the metal filler was 1.10% by volume with respect to the volume of the pressure-sensitive adhesive layer to be formed. About the obtained adhesive layer, a value was computed by Formula (1) mentioned above.

（実施例２～１３、比較例１～４）
粘着剤層の厚み、及び、金属フィラー（種類、形状、粒子径及び配合量）を表１に示したように変更した以外は実施例１と同様にして、導電性粘着テープを得た。
なお、実施例１３は、導電性基材として銅箔（１８μｍ）の粘着剤層側にＺｎ／Ｎｉ合金層（Ｚｎ／Ｎｉ＝２０重量部／８０重量部、厚み８０ｎｍ）をスパッタにより形成したものを用いた。 (Examples 2 to 13, Comparative Examples 1 to 4)
A conductive pressure-sensitive adhesive tape was obtained in the same manner as in Example 1 except that the thickness of the pressure-sensitive adhesive layer and the metal filler (type, shape, particle size and blending amount) were changed as shown in Table 1.
In Example 13, a conductive foil was formed by sputtering a Zn / Ni alloy layer (Zn / Ni = 20 parts by weight / 80 parts by weight, thickness 80 nm) on the adhesive layer side of a copper foil (18 μm). Was used.

（実施例１４、１５）
（アクリル共重合体含有溶液（ｂ）の調製）
滴下添加するモノマーを２－エチルヘキシルアクリレート３６．８重量部、ブチルアクリレート６０重量部、アクリル酸３重量部、２－ヒドロキシエチルアクリレート０．２重量部に変更した以外は、アクリル共重合体含有溶液（ａ）の調製と同様にしてアクリル共重合体含有溶液（ｂ）（アクリル共重合体の重量平均分子量（Ｍｗ）：１１０万）を得た。 (Examples 14 and 15)
(Preparation of acrylic copolymer-containing solution (b))
Acrylic copolymer-containing solution (except that the monomer to be added dropwise was changed to 36.8 parts by weight of 2-ethylhexyl acrylate, 60 parts by weight of butyl acrylate, 3 parts by weight of acrylic acid, and 0.2 parts by weight of 2-hydroxyethyl acrylate) An acrylic copolymer-containing solution (b) (weight average molecular weight (Mw) of acrylic copolymer: 1.1 million) was obtained in the same manner as in preparation of a).

（導電性粘着テープの調製）
粘着剤層の厚み、及び、金属フィラー（種類、形状、粒子径及び配合量）を表１に示したように変更した以外は、実施例１と同様にして、導電性粘着テープを得た。 (Preparation of conductive adhesive tape)
A conductive pressure-sensitive adhesive tape was obtained in the same manner as in Example 1 except that the thickness of the pressure-sensitive adhesive layer and the metal filler (type, shape, particle size and blending amount) were changed as shown in Table 1.

＜評価＞
実施例、比較例で得られた導電性粘着テープについて下記の評価を行った。結果を表１に示した。 <Evaluation>
The following evaluation was performed about the electroconductive adhesive tape obtained by the Example and the comparative example. The results are shown in Table 1.

（１）電磁波シールド性
導電性粘着テープを４１ｍｍ×５０ｍｍの平面長方形状に裁断し、試験片を作製した。ＫＥＣ装置（テクノサイエンスジャパン社製）の電界測定用冶具を準備し、中心に３８ｍｍ×４８ｍｍの穴のあいた３ｍｍ厚の銅板を下冶具に設置した。試験片を、各辺の貼り付け幅が１．５ｍｍになるよう、穴形に合わせて銅板に貼り付けた。そこに冶具の上蓋を被せ、充分に締め付けた。ネットワークアナライザ（ＫＥＹＳＩＧＨＴ　ＴＥＣＨＮＯＬＯＧＩＥＳ社製、Ｅ５０７１Ｃ）を用い、１００ＭＨｚから８ＧＨｚで試験片の電磁波シールド性を測定した。３８ｍｍ×４８ｍｍの穴のあいた３ｍｍ厚の銅板を設置した状態で、試験片がない場合の値を校正値とした。なお、１ＧＨｚでの測定結果が６５ｄＢ以上であった場合に充分な電磁波シールド性を有すると判断した。 (1) The electromagnetic wave shielding conductive adhesive tape was cut into a flat rectangular shape of 41 mm × 50 mm to prepare a test piece. A jig for electric field measurement of a KEC apparatus (manufactured by Techno Science Japan Co., Ltd.) was prepared, and a 3 mm thick copper plate with a 38 mm × 48 mm hole in the center was installed in the lower jig. The test piece was affixed to a copper plate according to the hole shape so that the affixing width of each side was 1.5 mm. The jig was covered with an upper lid and tightened sufficiently. Using a network analyzer (manufactured by KEYSIGN TECHNOLOGIES, E5071C), the electromagnetic wave shielding property of the test piece was measured from 100 MHz to 8 GHz. A calibration value was obtained when a 3 mm thick copper plate with a 38 mm × 48 mm hole was installed and no test piece was provided. In addition, when the measurement result in 1 GHz was 65 dB or more, it judged that it had sufficient electromagnetic wave shielding property.

（２）導電性
導電性粘着テープを２５ｍｍ×７５ｍｍの長方形状に裁断し、試験片を作製した。２５ｍｍ幅の２枚の銅電極に試験片を貼り付けた。各電極への試験片の貼り付け面積は２５ｍｍ×２５ｍｍとした。その後、温度２３℃及び湿度５０％ＲＨ試験室において、抵抗値を測定した。なお、抵抗値が低いほど、導電性に優れていることを意味する。測定限界を超え、抵抗値が測定できなかった場合は「Ｏ．Ｌ．」と示した。 (2) The conductive conductive adhesive tape was cut into a 25 mm × 75 mm rectangular shape to prepare a test piece. The test piece was affixed on two copper electrodes with a width of 25 mm. The area where the test piece was attached to each electrode was 25 mm × 25 mm. Thereafter, the resistance value was measured in a test room at a temperature of 23 ° C. and a humidity of 50% RH. In addition, it means that it is excellent in electroconductivity, so that resistance value is low. When the measurement limit was exceeded and the resistance value could not be measured, “OL” was indicated.

Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000001

本発明によれば、電磁波シールド性及び導電性に優れた導電性粘着テープを提供することができる。

 
  ADVANTAGE OF THE INVENTION According to this invention, the electroconductive adhesive tape excellent in electromagnetic wave shielding property and electroconductivity can be provided.


Claims (3)

導電性基材と、前記導電性基材の少なくとも一方の面に配置された粘着剤層とを有する導電性粘着テープであって、
前記粘着剤層は、アクリル共重合体と、金属フィラーとを含有し、下記式（１）により算出したａ値が０以上である
ことを特徴とする導電性粘着テープ。
ａ値＝（２５×Ｍ）＋｛２２×（ｄ７０／Ｄ）｝－３×（ｄ７０－ｄ４０）－１８　　（１）
Ｍ：前記粘着剤層の体積に対する前記金属フィラーの金属量（体積％）
Ｄ：前記粘着剤層の厚み（μｍ）
ｄ４０：体積基準の累積分布が４０％となるときの前記金属フィラーの粒子径（μｍ）
ｄ７０：体積基準の累積分布が７０％となるときの前記金属フィラーの粒子径（μｍ） A conductive pressure-sensitive adhesive tape having a conductive base material and a pressure-sensitive adhesive layer disposed on at least one surface of the conductive base material,
The said adhesive layer contains an acrylic copolymer and a metal filler, and the a value computed by following formula (1) is 0 or more, The electroconductive adhesive tape characterized by the above-mentioned.
a value = (25 × M) + {22 × (d70 / D)} − 3 × (d70−d40) −18 (1)
M: Metal content of the metal filler (volume%) relative to the volume of the pressure-sensitive adhesive layer
D: Thickness (μm) of the pressure-sensitive adhesive layer
d40: Particle size (μm) of the metal filler when the volume-based cumulative distribution is 40%
d70: Particle diameter (μm) of the metal filler when the cumulative distribution on the basis of volume is 70% 粘着剤層の厚み（Ｄ）に対する体積基準の累積分布が７０％となるときの金属フィラーの粒子径（ｄ７０）の比（ｄ７０／Ｄ）が０．６以上であることを特徴とする請求項１記載の導電性粘着テープ。 The ratio (d70 / D) of the particle diameter (d70) of the metal filler when the volume-based cumulative distribution with respect to the thickness (D) of the pressure-sensitive adhesive layer is 70% is 0.6 or more. The conductive adhesive tape according to 1. 粘着剤層の厚み（Ｄ）が３０μｍ以下であることを特徴する請求項１又は２記載の導電性粘着テープ。

  The conductive adhesive tape according to claim 1 or 2, wherein the adhesive layer has a thickness (D) of 30 µm or less.

PCT/JP2019/003396 2018-02-01 2019-01-31 Electroconductive pressure-sensitive adhesive tape Ceased WO2019151398A1 (en)

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