JP2014234444A - Electroconductive double-sided adhesive tape - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electroconductive double-sided adhesive tape that has anticorrosiveness while having electroconductivity and adhesiveness.SOLUTION: An electroconductive double-sided adhesive tape 1 comprises an electroconductive adhesive layer that comprises electroconductive particles and acrylic polymers, and has a water absorption of 2% or less.

Description

  The present invention relates to a conductive double-sided pressure-sensitive adhesive tape.

  As shown in Patent Document 1, a double-sided pressure-sensitive adhesive tape (conductive double-sided pressure-sensitive adhesive tape) having conductivity used for electrical connection between an electrode of a solar battery cell and a wiring member is known. As shown in Patent Document 1, this type of pressure-sensitive adhesive tape includes a pressure-sensitive adhesive layer in which conductive particles such as nickel powder are dispersed in a thermosetting resin such as an epoxy resin.

JP 2007-214533 A

  However, depending on the usage environment of the adhesive tape, there may be a case where there is a lot of moisture such as rain water or moisture around the adhesive tape. In such a case, if the pressure-sensitive adhesive layer of the pressure-sensitive adhesive tape absorbs moisture, the adherend (for example, electrode) to which the conductive double-sided pressure-sensitive adhesive tape is attached may be corroded.

  An object of the present invention is to solve the above-described problems and achieve the following objects. That is, an object of the present invention is to provide a conductive double-sided pressure-sensitive adhesive tape having corrosion resistance while having conductivity and adhesiveness.

  As a result of intensive studies to achieve the above object, the present inventor has a conductive double-sided pressure-sensitive adhesive tape comprising a conductive pressure-sensitive adhesive layer containing conductive particles and an acrylic polymer and having a water absorption of 2% or less. It has been found that it has corrosion resistance while having conductivity and adhesiveness, and has completed the present invention.

  In the conductive double-sided adhesive tape, the acrylic polymer may include 0.01 to 2% by mass of a structural unit derived from a hydroxyl group-containing monomer.

  In the conductive double-sided pressure-sensitive adhesive tape, the conductive particles may be contained in an amount of 0.8 to 4% by volume in the conductive pressure-sensitive adhesive layer.

  In the conductive double-sided pressure-sensitive adhesive tape, the thickness t of the conductive pressure-sensitive adhesive layer may be 7 μm to 190 μm.

In the conductive double-sided pressure-sensitive adhesive tape, the conductive particles may have an average particle diameter d ₅₀ (μm) of 0.10 μm to 190 μm.

In the conductive double-sided adhesive tape, the conductive particles may have an electrical resistance of ^{1.0 × 10 -8 Ωm~10.0 × 10 -8} Ωm.

  In the conductive double-sided adhesive tape, the acrylic polymer may contain 85 to 98% by mass of a structural unit derived from a (meth) acrylic acid alkyl ester.

In the conductive double-sided pressure-sensitive adhesive tape, the ratio (t / d ₅₀ ) of the thickness t (μm) of the conductive pressure-sensitive adhesive layer to the average particle diameter d ₅₀ (μm) of the conductive particles is 1 or more. The range may be 19 or less.

  ADVANTAGE OF THE INVENTION According to this invention, while providing electroconductivity and adhesiveness, the electroconductive double-sided adhesive tape provided with corrosion resistance can be provided.

Explanatory drawing which shows the structure of a conductive double-sided adhesive tape Schematic showing the evaluation method of resistance value Schematic showing the evaluation method of step following ability

(Conductive double-sided adhesive tape)
The conductive double-sided pressure-sensitive adhesive tape according to the present embodiment comprises a conductive pressure-sensitive adhesive layer containing conductive particles and an acrylic polymer and having a water absorption of 2% or less. The form of the conductive double-sided pressure-sensitive adhesive tape may be a so-called base material-less conductive double-sided pressure-sensitive adhesive tape that does not have a conductive base material, or a conductive base material that has so-called base material conductivity. A double-sided adhesive tape may be used. Examples of the base material-less conductive double-sided pressure-sensitive adhesive tape include a conductive double-sided pressure-sensitive adhesive tape comprising only a conductive pressure-sensitive adhesive layer. On the other hand, as said electroconductive double-sided adhesive tape with a base material, as FIG. 1 shows, for example, the electroconductive double-sided adhesive in which the electroconductive adhesive layer 3 was each formed in both surfaces of the electroconductive base material 2 Tape 1 is mentioned.

  In general, “conductive double-sided pressure-sensitive adhesive tape” is sometimes referred to by a different name from “conductive double-sided pressure-sensitive adhesive sheet”, “conductive double-sided pressure-sensitive adhesive film”, etc. Standardized double-sided adhesive tape. Further, the conductive adhesive layer in the conductive double-sided pressure-sensitive adhesive tape may be simply referred to as “adhesive layer”, and the surface of the conductive adhesive layer may be referred to as “adhesive surface”.

(Conductive substrate)
A conductive base material consists of a thin base material which has electroconductivity, such as metal foil. As the conductive substrate, metal foil is preferable. The material of the metal foil is not particularly limited as long as it has conductivity, and is appropriately selected according to the purpose. Examples of the material of the metal foil used for the conductive substrate include aluminum, copper, nickel, silver, iron, and alloys thereof. Among these, aluminum foil and copper foil are preferable from the viewpoint of conductivity, economy, workability, and the like, and aluminum foil is particularly preferable.

  The thickness of the conductive substrate is not particularly limited, but is preferably 10 μm to 100 μm, for example, 20 μm from the viewpoints of weight reduction, thinning, economy, step following ability, etc. of the conductive double-sided adhesive tape. ˜80 μm is more preferable, and 25 μm to 75 μm is particularly preferable.

(Conductive adhesive layer)
The conductive adhesive layer is a layer that provides the adhesive surface of the conductive double-sided adhesive tape. The conductive pressure-sensitive adhesive layer comprises at least an acrylic polymer and conductive particles. Further, the conductive pressure-sensitive adhesive layer may contain a tackifier resin and other components as necessary.

(Acrylic polymer)
The acrylic polymer is used as a pressure-sensitive adhesive base polymer in the conductive pressure-sensitive adhesive layer, and is a polymer composed of (meth) acrylic acid alkyl ester as a main monomer component. The acrylic polymer may contain a carboxyl group-containing monomer or a hydroxyl group-containing monomer as a copolymerization monomer component in addition to the monomer main component. Further, other monomer components may be used as necessary. In the present specification, “(meth) acryl” means “acryl” and / or “methacryl” (one or both of “acryl” and “methacryl”).

  The (meth) acrylic acid alkyl ester is not particularly limited as long as it is a (meth) acrylic acid alkyl ester having an alkyl group having 1 to 12 carbon atoms. Examples of the (meth) acrylic acid alkyl ester include, for example, methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, isopropyl (meth) acrylate, and (meth) acrylic acid n-. Butyl, isobutyl (meth) acrylate, sec-butyl (meth) acrylate, t-butyl (meth) acrylate, pentyl (meth) acrylate, isopentyl (meth) acrylate, neopentyl (meth) acrylate, (meta ) Hexyl acrylate, heptyl (meth) acrylate, octyl (meth) acrylate, isooctyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, nonyl (meth) acrylate, isononyl (meth) acrylate, ( (Meth) acrylic acid decyl, (meth) acrylic acid isodecyl, (meth) acrylic acid Le acid undecyl, (meth) dodecyl acrylate.

  Among the (meth) acrylic acid alkyl esters, (meth) acrylic acid alkyl esters having an alkyl group having 4 to 12 carbon atoms are preferred, and n-butyl acrylate (BA) and 2-ethylhexyl acrylate (2EHA) are preferred. Particularly preferred.

  The said (meth) acrylic-acid alkylester may be used individually or in combination of 2 or more types.

  The acrylic polymer preferably contains 85 to 98% by mass, more preferably 88 to 98% by mass, and 90 to 98% by mass of the structural unit derived from the (meth) acrylic acid alkyl ester. Particularly preferred.

  Examples of the carboxyl group-containing monomer include (meth) acrylic acid, itaconic acid, maleic acid, fumaric acid, crotonic acid, and isocrotonic acid. In addition, acid anhydrides of these carboxyl group-containing monomers (for example, acid anhydride group-containing monomers such as maleic anhydride and itaconic anhydride) can also be used as the carboxyl group-containing monomer. These monomer components may be used alone or in combination of two or more.

  The acrylic polymer preferably contains 1 to 20% by mass of structural units derived from the carboxyl group-containing monomer, more preferably 1 to 15% by mass, and particularly preferably 1 to 10% by mass.

  Examples of the hydroxyl group-containing monomer include 2-hydroxyethyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 6-hydroxyhexyl (meth) acrylate, Examples include vinyl alcohol and allyl alcohol. These monomer components may be used alone or in combination of two or more. Among the hydroxyl group-containing monomers, 4-hydroxybutyl (meth) acrylate is preferable, and 4-hydroxybutyl acrylate is particularly preferable.

  The acrylic polymer preferably contains 0.01 to 2% by mass, more preferably 0.01 to 1% by mass of a structural unit derived from the hydroxyl group-containing monomer, and 0.01 to 0.08. It is particularly preferable to contain it in mass%.

  Examples of other copolymerization monomer components include (meth) acrylamide, N, N-dimethyl (meth) acrylamide, N-methylol (meth) acrylamide, N-methoxymethyl (meth) acrylamide, and N-butoxymethyl (meth). Amide group-containing monomers such as acrylamide and N-hydroxyethyl (meth) acrylamide; amino group-containing monomers such as aminoethyl (meth) acrylate, dimethylaminoethyl (meth) acrylate, and t-butylaminoethyl (meth) acrylate Epoxy group-containing monomers such as glycidyl (meth) acrylate and methyl glycidyl (meth) acrylate; cyano group-containing monomers such as acrylonitrile and methacrylonitrile; N-vinyl-2-pyrrolidone, (meth) acryloylmorpholine, N- Vinyl piperidone Heterocycle-containing vinyl monomers such as N-vinylpiperazine, N-vinylpyrrole and N-vinylimidazole; sulfonic acid group-containing monomers such as sodium vinylsulfonate; phosphate group-containing monomers such as 2-hydroxyethylacryloyl phosphate; Imide group-containing monomers such as cyclohexylmaleimide and isopropylmaleimide; Isocyanate group-containing monomers such as 2-methacryloyloxyethyl isocyanate; (Meth) acrylic acid alkoxyalkyl esters such as methoxyethyl (meth) acrylate and ethoxyethyl (meth) acrylate Polyfunctional monomers such as triethylene glycol diacrylate, ethylene glycol dimethacrylate, trimethylolpropane tri (meth) acrylate; vinyl acetate, vinyl propionate, etc. Vinyl ester-based monomer, ethylene, propylene, isoprene, butadiene and the like olefinic monomers; vinyl ether monomers such as vinyl ether. These monomer components may be used alone or in combination of two or more.

  The acrylic polymer may include 10% by mass or less of a structural unit derived from the copolymerization monomer component.

  The content of the acrylic polymer in the adhesive base polymer of the conductive adhesive layer is preferably 50% by mass to 100% by mass, more preferably 70% by mass to 100% by mass, and particularly preferably 90% by mass to 100% by mass. .

  In addition, in the range which does not impair the objective of this invention, base polymers other than an acrylic polymer may be used as a base polymer in a conductive adhesive layer. Examples of the base polymer include polyisoprene rubber, styrene / butadiene (SB) rubber, styrene / isoprene (SI) rubber, styrene / isoprene / styrene block copolymer (SIS) rubber, and styrene / butadiene / styrene block copolymer. Combined (SBS) rubber, Styrene / ethylene / butylene / styrene block copolymer (SEBS) rubber, Styrene / ethylene / propylene / styrene block copolymer (SEPS) rubber, Styrene / ethylene / propylene block copolymer (SEP) Rubber polymers such as rubber, recycled rubber, butyl rubber, polyisobutylene, and modified rubbers thereof, rubber polymers such as natural rubber; silicone polymers; base polymers used for known adhesives such as vinyl ester polymers . These may be used alone or in combination of two or more.

  The acrylic polymer can be prepared by a known polymerization method. Examples of the polymerization method include a solution polymerization method, an emulsion polymerization method, a bulk polymerization method, and a photopolymerization method. In the case of this embodiment, the solution polymerization method is preferable from the viewpoints of the dispersibility and economical efficiency of the conductive particles.

  The polymerization initiator, chain transfer agent and the like used for the polymerization of the acrylic polymer are not particularly limited, and are appropriately selected from known ones.

  Examples of the polymerization initiator include 2,2′-azobisisobutyronitrile, 2,2′-azobis (4-methoxy-2,4-dimethylvaleronitrile), 2,2′-azobis (2, 4-dimethylvaleronitrile), 2,2′-azobis (2-methylbutyronitrile), 1,1′-azobis (cyclohexane-1-carbonitrile), 2,2′-azobis (2,4,4- Azo polymerization initiators such as trimethylpentane) and dimethyl-2,2′-azobis (2-methylpropionate); benzoyl peroxide, t-butyl hydroperoxide, di-t-butyl peroxide, t-butyl Peroxybenzoate, dicumyl peroxide, 1,1-bis (t-butylperoxy) 3,3,5-trimethylcyclohexane, 1,1-bis ( - butylperoxy) an oil-soluble polymerization initiator such as peroxide polymerization initiators cyclododecane, and the like. The said polymerization initiator may be used individually or in combination of 2 or more types. The usage-amount of the said polymerization initiator may be suitably selected from the range of about 0.01-1 mass part with respect to 100 mass parts of all the monomer components, for example.

  Examples of the chain transfer agent include lauryl mercaptan, glycidyl mercaptan, mercaptoacetic acid, 2-mercaptoethanol, thioglycolic acid, 2-ethylhexyl thioglycolate, and 2,3-dimercapto-1-propanol. The chain transfer agents may be used alone or in combination of two or more.

  As a solvent (solvent) used for the polymerization of the acrylic polymer, various general solvents can be used. Examples of the solvent include esters such as ethyl acetate and n-butyl acetate; aromatic hydrocarbons such as toluene and benzene; aliphatic hydrocarbons such as n-hexane and n-heptane; cyclohexane and methylcyclohexane Organic solvents such as ketones such as methyl ethyl ketone and methyl isobutyl ketone. The said solvent may be used individually or in combination of 2 or more types.

  The weight average molecular weight (Mw) of the acrylic polymer is 300,000 to 1,000,000 from the viewpoints of the coating property of the solution containing the acrylic polymer, the step following property of the conductive adhesive layer containing the acrylic polymer, and the like. Is preferable, and 400,000 to 800,000 is more preferable. The weight average molecular weight of the acrylic polymer can be controlled by appropriately adjusting the type and amount of each component such as a polymerization initiator, polymerization conditions such as polymerization time and polymerization temperature. The weight average molecular weight (Mw) of the acrylic polymer can be measured by, for example, a gel permeation chromatograph (GPC) method.

(Conductive particles)
As the conductive particles (conductive filler), conductive particles such as metal powder are used. Examples of materials used for the conductive particles include nickel, iron, chromium, cobalt, aluminum, antimony, molybdenum, copper, silver, platinum, gold and other metals, stainless steel alloys, metal oxides, carbon black, and the like. And conductive materials such as carbon. The conductive particles may be particles (powder) made of the conductive material, or may be metal-coated particles obtained by metal-coating the surface of particles such as polymer beads and glass beads. The conductive particles may be used alone or in combination of two or more.

  As the conductive particles, metal particles such as nickel, silver and stainless steel are preferable, metal particles such as nickel and silver are more preferable, and silver particles (silver powder) are preferable from the viewpoint of good conductivity (low electric resistance value) and the like. Particularly preferred.

  The shape of the conductive particles is spherical or the like and is appropriately selected from known ones.

Conductive average particle size _{d 50} of the particles is preferably 0.10Myuemu～190myuemu, more preferably 0.36μm~150μm, 0.36μm~100μm is particularly preferred. The average particle size d ₅₀ of the electrically conductive particles is 50% cumulative value in the particle size distribution (median diameter). The average particle size d ₅₀ is measured, for example, by a laser diffraction scattering method described below. In addition, when 2 or more types of electroconductive particle is contained in an electroconductive adhesive layer, the said average particle diameter is computed from the distribution which mixed all the electroconductive particles.

  As electroconductive particle, the Fukuda metal foil powder industry make and brand name "Ag-HWQ-400" can be used, for example.

The electrical resistivity (Ωm) of the conductive particles is not particularly limited and is appropriately selected according to the purpose. For example, 1.00 × 10 ⁻⁸ Ωm to 1.00 × 10 ⁻⁵ Ωm is preferable, and 1 0.000 × 10 ⁻⁸ Ωm to 1.00 × 10 ⁻⁶ Ωm is more preferable, and 1.00 × 10 ⁻⁸ Ωm to 1.00 × 10 ⁻⁷ Ωm is particularly preferable. When the electrical resistivity of the conductive particles is within such a range, the resistance value of the conductive pressure-sensitive adhesive layer can be lowered. The specific electric resistance values of the conductive particles are, for example, silver: 1.59 × 10 ⁻⁸ Ωm, nickel: 6.99 × 10 ⁻⁸ Ωm, stainless steel: 72.0 × 10 ⁻⁸ Ωm. .

  The compounding quantity of electroconductive particle is 5-100 mass parts with respect to 100 mass parts of solid content of the adhesive base polymer (for example, acrylic polymer) in the adhesive composition for forming a conductive adhesive layer. Is preferable, 5-80 mass parts is more preferable, and 5-50 mass parts is especially preferable. When the blending amount of the conductive particles is within such a range, both the conductivity and the adhesive strength of the conductive adhesive layer can be achieved.

  In addition, 1-15 volume% is preferable, for example, 1-15 volume% is more preferable, for example, 1-10 volume% is more preferable, and 1-10 volume% is especially preferable for the volume addition amount (volume%) of a conductive adhesive layer. When the volume addition amount of the conductive particles is within such a range, both the conductivity and the adhesive force of the conductive adhesive layer can be achieved.

For example, when the conductive pressure-sensitive adhesive layer contains an acrylic polymer, a pressure-sensitive adhesive resin, and a crosslinking agent together with the conductive particles, the volume addition amount (% by volume) of the conductive particles can be obtained by the following calculation formula.
Volume addition amount (% by volume) = {(Blend amount of conductive particles (g)) / (Specific gravity of conductive particles (g / cm ³ )} / {(Blend amount of acrylic polymer (g)) / (Acrylic Specific gravity (g / cm ³ )) + (tackifying resin blending amount (g)) / (tackifying resin specific gravity (g / cm ³ )) + (crosslinking agent blending amount (g)) / ( Specific gravity of crosslinking agent (g / cm ³ ))} × 100
In addition, since specific gravity, such as an acrylic polymer, tackifying resin, and a crosslinking agent, will generally be 1 g / cm < ³ >, you may calculate with this value.

  The conductive pressure-sensitive adhesive layer may contain a tackifying resin as a component other than the base polymer such as an acrylic polymer. Examples of the tackifier resin include terpene tackifier resins, phenol tackifier resins, rosin tackifier resins, and petroleum tackifier resins. As the tackifier resin, a rosin tackifier resin is particularly preferable. The tackifier resins may be used alone or in combination of two or more.

  Examples of the terpene-based tackifier resins include terpene resins such as α-pinene polymers, β-pinene polymers, and dipentene polymers, and modifications of these terpene resins (phenol modification, aromatic modification, hydrogenation modification). Modified terpene resins (for example, terpene phenol resins, styrene modified terpene resins, aromatic modified terpene resins, hydrogenated terpene resins, etc.) and the like.

  Examples of the phenol-based tackifying resin include condensates (for example, alkylphenol-based resins, xylene) of various phenols (for example, phenol, m-cresol, 3,5-xylenol, p-alkylphenol, resorcin, etc.) and formaldehyde. Formaldehyde resins), resols obtained by addition reaction of the phenols and formaldehyde with an alkali catalyst, novolaks and rosins obtained by condensation reaction of the phenols and formaldehyde with an acid catalyst (unmodified rosin, modified) Examples thereof include rosin-modified phenol resins obtained by adding phenol to rosin and various rosin derivatives with an acid catalyst and performing thermal polymerization.

  Examples of the rosin-based tackifying resin include unmodified rosins such as gum rosin, wood rosin, tall oil rosin (raw rosin), and modified rosins modified by hydrogenation, disproportionation, polymerization, etc. of these unmodified rosins ( Hydrogenated rosin, disproportionated rosin, polymerized rosin, other chemically modified rosins, etc.) and various rosin derivatives. Examples of the rosin derivatives include rosin ester compounds obtained by esterifying unmodified rosin with alcohols, hydrogenated rosin, disproportionated rosin, and polymerized rosin. Rosin esters such as ester compounds; Unmodified rosin, Unmodified rosin (hydrogenated rosin, disproportionated rosin, polymerized rosin, etc.) modified with unsaturated fatty acids; Unsaturated fatty acid modified rosins; Rosin esters with unsaturated fatty acids Modified unsaturated fatty acid modified rosin esters; reduction of carboxyl groups in unmodified rosin, modified rosin (hydrogenated rosin, disproportionated rosin, polymerized rosin, etc.), unsaturated fatty acid modified rosins and unsaturated fatty acid modified rosin esters Treated rosin alcohols; rosins such as unmodified rosin, modified rosin, various rosin derivatives (In particular, rosin esters), and metal salts of.

  Examples of the petroleum-based tackifier resins include aromatic petroleum resins, aliphatic petroleum resins, alicyclic petroleum resins (aliphatic cyclic petroleum resins), aliphatic / aromatic petroleum resins, aliphatic / aliphatic resins. Well-known petroleum resins such as cyclic petroleum resins, hydrogenated petroleum resins, coumarone resins, coumarone indene resins and the like can be mentioned.

  The compounding quantity of tackifying resin is 5-50 mass parts with respect to 100 mass parts of solid content of the adhesive base polymer (for example, acrylic polymer) in the adhesive composition for forming a conductive adhesive layer. Is preferable, 10-50 mass parts is more preferable, and 10-40 mass parts is especially preferable. When the compounding amount of the tackifying resin is in such a range, the adhesive force in the conductive adhesive layer can be sufficiently expressed.

  A crosslinking agent may be added to the pressure-sensitive adhesive base polymer such as an acrylic polymer used for the conductive pressure-sensitive adhesive layer. Examples of the crosslinking agent include an isocyanate crosslinking agent, an epoxy crosslinking agent, a melamine crosslinking agent, a peroxide crosslinking agent, a urea crosslinking agent, a metal alkoxide crosslinking agent, a metal chelate crosslinking agent, and a metal salt crosslinking agent. Examples include a crosslinking agent, a carbodiimide crosslinking agent, an oxazoline crosslinking agent, an aziridine crosslinking agent, and an amine crosslinking agent. As the crosslinking agent, an isocyanate-based crosslinking agent is particularly preferable. The said crosslinking agent may be used individually or in combination of 2 or more types.

  Examples of the isocyanate-based crosslinking agent include lower aliphatic polyisocyanates such as 1,2-ethylene diisocyanate, 1,4-butylene diisocyanate, and 1,6-hexamethylene diisocyanate; cyclopentylene diisocyanate, cyclohexylene diisocyanate, Cycloaliphatic polyisocyanates such as isophorone diisocyanate, hydrogenated tolylene diisocyanate, hydrogenated xylene diisocyanate; 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 4,4′- Aromatic polyisocyanates such as diphenylmethane diisocyanate and xylylene diisocyanate, trimethylolpropane / tolylene diisocyanate trimer adduct [trade name “Coronate L” manufactured by Nippon Polyurethane Industry Co., Ltd. , Trimethylolpropane / hexamethylene diisocyanate trimer adduct [Nippon Polyurethane Industry Co., Ltd. under the trade name "Coronate HL"], and the like.

  Examples of the epoxy-based crosslinking agent include N, N, N ′, N′-tetraglycidyl-m-xylenediamine, diglycidylaniline, 1,3-bis (N, N-glycidylaminomethyl) cyclohexane, 1, 6-hexanediol diglycidyl ether, neopentyl glycol diglycidyl ether, ethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, sorbitol polyglycidyl ether, glycerol polyglycidyl ether, penta Erythritol polyglycidyl ether, polyglycerol polyglycidyl ether, sorbitan polyglycidyl ether, trimethylolpropane polyglycid Ether, adipic acid diglycidyl ester, o-phthalic acid diglycidyl ester, triglycidyl-tris (2-hydroxyethyl) isocyanurate, resorcin diglycidyl ether, bisphenol-S-diglycidyl ether, two epoxy groups in the molecule The epoxy resin etc. which have the above are mentioned.

  The compounding quantity of a crosslinking agent is 0.001-10 mass with respect to 100 mass parts of solid content of the adhesive base polymer (for example, acrylic polymer) in the adhesive composition for forming a conductive adhesive layer. Part is preferred.

  As long as the conductive adhesive layer does not impair the object of the present invention, known anti-aging agents, colorants (pigments, dyes, etc.), ultraviolet absorbers, antioxidants, plasticizers, softeners, surfactants, etc. The additive may be blended.

  Moreover, the composition which consists of an adhesive base polymer etc. for forming an electroconductive adhesive layer may be used as a solution by which the viscosity was adjusted suitably with the various general solvent. Examples of the solvent include esters such as ethyl acetate and n-butyl acetate; aromatic hydrocarbons such as toluene and benzene; aliphatic hydrocarbons such as n-hexane and n-heptane; cyclohexane and methylcyclohexane Organic solvents such as ketones such as methyl ethyl ketone and methyl isobutyl ketone. The said solvent may be used individually or in combination of 2 or more types.

(Release liner)
The conductive double-sided pressure-sensitive adhesive tape of this embodiment may include a release liner for protecting the pressure-sensitive adhesive surface of each conductive pressure-sensitive adhesive layer until use. Such a release liner is not particularly limited, and can be appropriately selected from known release liners.

  Examples of the release liner include a base material having a release layer such as a plastic film or paper surface-treated with a release agent such as silicone, long-chain alkyl, fluorine, or molybdenum sulfide; polytetrafluoroethylene, polychlorotri Low adhesion substrate made of fluoropolymer such as fluoroethylene, polyvinyl fluoride, polyvinylidene fluoride, tetrafluoroethylene / hexafluoropropylene copolymer, chlorofluoroethylene / vinylidene fluoride copolymer; olefin resin (for example, , Polyethylene, polypropylene, etc.) and other low-adhesive substrates made of nonpolar polymers.

(Method for forming conductive adhesive layer)
Although it does not specifically limit as a formation method of the electroconductive adhesive layer in the electroconductive double-sided adhesive tape of this embodiment, For example, the adhesive composition for forming an electroconductive adhesive layer is made into a conductive base material or peeling. The method of apply | coating (coating) to a liner and drying and / or hardening | curing as needed is mentioned.

  In addition, a well-known coating method can be used for application | coating (coating) in the formation method of an electroconductive adhesive layer. Examples of the coating method include a method using a coater such as a gravure roll coater, a reverse roll coater, a kiss roll coater, a dip roll coater, a bar coater, a knife coater, a spray coater, a comma coater, and a direct coater.

(Form of conductive double-sided adhesive tape)
The conductive double-sided pressure-sensitive adhesive tape of the present embodiment can take the form of a general double-sided pressure-sensitive adhesive tape. For example, the conductive double-sided pressure-sensitive adhesive tape of the present embodiment may have a form that spreads in a planar shape, or may have a form of a wound body wound in a roll shape.

(Thickness t of conductive adhesive layer)
Although the thickness of the electroconductive adhesive layer in the electroconductive double-sided adhesive tape of this embodiment is not specifically limited, For example, 10 micrometers-200 micrometers are preferable, 10 micrometers-170 micrometers are more preferable, 10 micrometers-150 micrometers are especially preferable. When the thickness of the conductive pressure-sensitive adhesive layer is in such a range, the step following property of the conductive pressure-sensitive adhesive layer is improved.

  When the conductive double-sided pressure-sensitive adhesive tape includes two conductive pressure-sensitive adhesive layers, they may be the same as each other or different from each other.

  The conductive double-sided pressure-sensitive adhesive tape of this embodiment includes other layers (for example, an intermediate layer, an undercoat layer, etc.) in addition to the conductive base material and the conductive pressure-sensitive adhesive layer as long as the object of the present invention is not impaired. It may be.

(T / d ₅₀ )
In the conductive double-sided pressure-sensitive adhesive tape of the present embodiment, the ratio (t / d ₅₀ ) of the thickness t (μm) of the conductive pressure-sensitive adhesive layer to the average particle diameter d ₅₀ (μm) of the conductive particles is 1 It is preferably in the range of 19 or less, more preferably 1 to 10 or less, particularly preferably 1 to 4 or less. When the value of t / d ₅₀ is in such a range, the conductive double-sided pressure-sensitive adhesive tape can achieve corrosion resistance as well as good conductivity and adhesive strength (adhesive strength).

(Use)
The conductive double-sided pressure-sensitive adhesive tape of the present embodiment has good adhesion (adhesive strength), electrical conductivity, and good corrosion resistance. -It is suitably used for electromagnetic shielding applications of electronic devices and cables. In particular, in applications under various environments and for long-term use, applications that require stable electrical conductivity without increasing the resistance value, specifically, for example, printed circuit boards Grounding, grounding of outer shield case of electronic equipment, grounding for preventing static electricity, power supply device and electronic equipment (for example, portable information terminal, liquid crystal display device, organic EL (electroluminescence) display device, PDP (plasma display panel) ), Internal wiring of display devices such as electronic paper, solar cells, etc.).

  The conductive double-sided pressure-sensitive adhesive tape of the present embodiment has a good adhesive force (adhesive force) and conductivity, and also has corrosion resistance. In addition, the conductive double-sided pressure-sensitive adhesive tape according to the present embodiment has, in addition, step following ability, adhesion reliability at high temperature (for example, 200 ° C. or more (specifically, about 260 ° C.)), and swelling reliability at high temperature heating, etc. For example, adhesion reliability due to prevention of deterioration of adhesion due to volume change).

  Although the adhesive force of the electroconductive adhesive layer in the electroconductive double-sided adhesive tape of this embodiment is not specifically limited, For example, 5 (N / 20mm) -50 (N / 20mm) are preferable, and 5 (N / 20mm)- 40 (N / 20 mm) is more preferable, and 5 (N / 20 mm) to 35 (N / 20 mm) is particularly preferable.

  Although the resistance value of the electroconductive double-sided adhesive tape of this embodiment is not specifically limited, For example, 0.1Ω-10Ω is preferable, 0.1Ω-8Ω is more preferable, and 0.1Ω-5Ω is particularly preferable.

Although the storage elastic modulus (temperature condition 23 degreeC) in the electroconductive double-sided adhesive tape (conductive adhesive layer) of this embodiment is not specifically limited, For example, 3.0 * 10 < ⁵ > Pa or less is preferable and 2.90 *. 10 ⁵ Pa or less is more preferable, and 2.50 × 10 ⁵ Pa or less is particularly preferable.

Although the storage elastic modulus (temperature condition 70 degreeC) in the electroconductive double-sided adhesive tape (conductive adhesive layer) of this embodiment is not specifically limited, For example, 0.4 * 10 < ⁵ > Pa or more and 8.0 * 10 < ⁵ > Pa The following is preferred.

  Hereinafter, the present invention will be described in more detail based on examples. In addition, this invention is not limited at all by these Examples.

[Example 1]
70 parts by mass of n-butyl acrylate (BA), 30 parts by mass of 2-ethylhexyl acrylate (2EHA), 3 parts by mass of acrylic acid (AA), 0.05 part by mass of 4-hydroxybutyl acrylate (4HBA), and toluene as a solvent In addition, 0.1 parts by mass of azobisisobutyronitrile was used as an initiator for solution polymerization by a conventional method (5 hours at 65 ° C., 2 hours at 80 ° C.), and an acrylic polymer (weight average molecular weight: about 50 Solution) (hereinafter referred to as polymer solution A). The solid content concentration of the polymer solution A was 40.0% by mass.

30 parts by mass of polymerized rosin pentaerythritol ester (trade name “Pencel D-125” manufactured by Arakawa Chemical Co., Ltd.) as a tackifier resin and 100 parts by mass of silver as conductive particles with respect to 100 parts by mass of the solid content of the polymer solution A Powder (made by Fukuda Metal Foil Powder Co., Ltd., trade name “Ag-HWQ-400”, particle size d ₅₀ = 10 μm) 35 parts by mass, isocyanate crosslinking agent (made by Nippon Polyurethane Co., Ltd., trade name “Coronate L”) 2 parts by mass and 100 parts by mass of toluene were blended and mixed with a stirrer for 10 minutes to obtain an adhesive composition solution A.

The average particle size d ₅₀ of the conductive particles was measured using a laser diffraction-scattering Microtrac particle size distribution analyzer MT3300 (manufactured by Nikkiso Co., Ltd.).
The solvent is water (refractive index: 1.33), and the sample concentration is a dv value (a dimensionless value obtained from the amount of scattered light obtained from the measurement particles. Measured with a numerical value proportional to the volume of the particles in the measurement unit. The sample (conductive particles) is added so that the concentration is in the range of 0.02 to 0.5, and ultrasonic waves are applied for 3 minutes using an ultrasonic device (output 40 W). Irradiation and measurement (measurement conditions: particle permeability... Reflection) were performed while circulating at a flow rate of 70% (35 cc / min). The average particle size d ₅₀ was determined in the same manner for the following examples and comparative examples.

(Production of conductive double-sided adhesive tape)
A pair of paper-made PET release liners 1 with one side peeled with silicone and a thickness of 50 μm, and a pair of PET with one side peeled with silicone and a thickness of 38 μm A release liner 2 made of metal was prepared. Moreover, the aluminum foil whose thickness is 50 micrometers was prepared as a base material.

  The pressure-sensitive adhesive composition solution A was applied on one side of one release liner 1 that had been subjected to a release treatment so that the thickness after the heat treatment was 30 μm. Subsequently, the coated material on the release liner 1 was heat-treated at 100 ° C. for 3 minutes to form one pressure-sensitive adhesive layer having a thickness of 30 μm. Next, one surface of a base material having a thickness of 50 μm was stuck on the pressure-sensitive adhesive layer.

  Subsequently, the pressure-sensitive adhesive composition solution A is applied on one surface of the release liner 2 so that the thickness after the heat treatment is 30 μm, and the applied material is heat-treated at 100 ° C. for 3 minutes, The other pressure-sensitive adhesive layer having a thickness of 30 μm was formed. Then, it laminated | stacked in the form which bonds an adhesive layer on the other surface of the said base material, and obtained the electroconductive double-sided adhesive tape.

  In addition, the thickness of the electroconductive adhesive layer was measured using the dial gauge prescribed | regulated to JISB7503. The contact surface of the dial gauge was a flat surface and the diameter was 5 mm. Using a test piece with a width of 150 mm, the thickness of five points was measured at equal intervals in the width direction with a dial gauge with a scale of 1/1000 mm, and the average value of the measurement results was taken as the thickness of the conductive adhesive layer. The thickness of the conductive pressure-sensitive adhesive layer was determined in the same manner for the following examples and comparative examples.

[Example 2]
As shown in Table 1, the substrate used was changed to an aluminum foil having a thickness of 40 μm, and the thickness of each pressure-sensitive adhesive layer formed on both surfaces of the substrate was changed to 25 μm. Example 1 In the same manner, a conductive double-sided adhesive tape was produced.

Example 3
As shown in Table 1, except that the conductive particles used were changed to 35 parts by mass of nickel powder (CuLox Technologies, Inc., trade name “Ni Powder CuLox 5100A”, particle size d ₅₀ = 10 μm). In the same manner as in Example 1, a conductive double-sided pressure-sensitive adhesive tape was produced.

Example 4
As shown in Table 1, the substrate to be used was changed to an aluminum foil having a thickness of 40 μm, and the conductive particles to be used were nickel powder (trade name “Ni Powder CuLox 5100A”, manufactured by CuLox Technologies, Inc., grains Diameter d ₅₀ = 10 μm) Conductive double-sided adhesive tape in the same manner as in Example 1, except that the thickness was changed to 35 parts by mass and the thickness of each adhesive layer formed on both sides of the substrate was changed to 25 μm. Was made.

Example 5
As shown in Table 1, the conductive particles used were changed to 35 parts by mass of stainless powder (product name “Stainless Steel SUS304”, particle size d ₅₀ = 100 μm, manufactured by Nilaco Co., Ltd.), and formed on both surfaces of the substrate. A conductive double-sided pressure-sensitive adhesive tape was produced in the same manner as in Example 1, except that the thickness of each pressure-sensitive adhesive layer was changed to 150 μm.

Example 6
90 parts by mass of 2-ethylhexyl acrylate (2EHA) and 10 parts by mass of acrylic acid (AA) were subjected to solution polymerization by a conventional method using toluene as a solvent and 0.1 parts by mass of azobisisobutyronitrile as an initiator. (5 hours at 65 ° C., 2 hours at 80 ° C.) to obtain a solution of an acrylic polymer (weight average molecular weight: about 500,000) (hereinafter, polymer solution B). The solid content concentration of the polymer solution B was 40.0% by mass.

  As shown in Table 1, an adhesive composition solution B was prepared in the same manner as in Example 1 except that the polymer solution B was changed. Further, as shown in Table 1, a conductive double-sided pressure-sensitive adhesive tape was produced in the same manner as in Example 1 except that the pressure-sensitive adhesive composition solution B was changed.

[Comparative Example 1]
As shown in Table 1, production of a conductive double-sided pressure-sensitive adhesive tape was attempted in the same manner as in Example 1 except that the thickness of each pressure-sensitive adhesive layer formed on both surfaces of the base material was changed to 5 μm. . However, since the anchoring property between the base material and the pressure-sensitive adhesive layer is low, the pressure-sensitive adhesive layer formed on one surface of the release liner 2 cannot be transferred onto the base material and thus cannot be produced.

[Comparative Example 2]
As shown in Table 1, a conductive double-sided pressure-sensitive adhesive tape was produced in the same manner as in Example 1 except that the thickness of each pressure-sensitive adhesive layer formed on both surfaces of the base material was changed to 200 μm.

[Comparative Example 3]
As shown in Table 1, a conductive double-sided pressure-sensitive adhesive tape was produced in the same manner as in Example 1 except that the blending amount of the silver powder was changed to 10 parts by mass.

[Comparative Example 4]
As shown in Table 1, production of a conductive double-sided pressure-sensitive adhesive tape was attempted in the same manner as in Example 1 except that the amount of silver powder was changed to 230 parts by mass. However, since the anchoring property between the base material and the pressure-sensitive adhesive layer is low, the pressure-sensitive adhesive layer formed on one surface of the release liner 2 cannot be transferred onto the base material and thus cannot be produced.

[Comparative Example 5]
80 parts by mass of 2-ethylhexyl acrylate (2EHA), 3 parts by mass of acrylic acid (AA), and 20 parts by mass of acryloylmorpholine (ACMO) are used as a solvent, and 0.1 part by mass of azobisisobutyronitrile is started. As an agent, solution polymerization was performed by a conventional method (5 hours at 65 ° C., 2 hours at 80 ° C.) to obtain a solution of an acrylic polymer (weight average molecular weight: about 500,000) (hereinafter, polymer solution C). The solid content concentration of the polymer solution C was 40.0% by mass.

  As shown in Table 1, an adhesive composition solution C was produced in the same manner as in Example 1 except that the polymer solution C was used. Moreover, as shown in Table 1, a conductive double-sided pressure-sensitive adhesive tape was produced in the same manner as in Example 1 except that the pressure-sensitive adhesive composition solution C was changed.

[Comparative Example 6]
As shown in Table 1, a conductive double-sided pressure-sensitive adhesive tape was produced in the same manner as in Example 1 except that the amount of silver powder was changed to 75 parts by mass.

[Evaluation]
(Measurement of resistance value)
A copper foil (rolled copper foil, thickness: 35 μm) was bonded to the conductive double-sided adhesive tapes obtained in Examples and Comparative Examples, and then a 30 mm wide × 40 mm long measurement sample was cut out. 2, a copper foil (rolled copper foil, thickness: 35 μm) 5 is placed on a glass plate (soda lime glass) 4, and an insulating tape 6 is overlaid on the copper foil 5, The copper foil 5 and the measurement sample are hand-roller (width 30 mm), pressure 5.0 N / pressure under normal temperature environment so that the area of the bonded portion 8 (in the region surrounded by the broken line in FIG. 2) is 4 cm ^2. Crimped with cm. In addition, it bonded together so that the vertical direction of FIG. 2 may be the length direction of a measurement sample, and the adhesive surface of the electroconductive adhesive layer of the said adhesive tape may contact the surface of the copper foil 5. FIG. After bonding, the substrate was allowed to stand for 15 minutes in a room temperature environment, and then the terminals of the ammeter were connected to the copper foil end portions (marked by the symbols T1 and T2 in FIG. 2), and the copper foil end portions (FIG. 2). The digital multimeter terminal is connected to the parts indicated by the symbols T3 and T4), and the potential difference when a current of 1A is passed through the ammeter (KIKUSUI, DC stabilized power supply PMC18-S) is digital. It measured with the multimeter (IWASUSU company make, VOAC7521A). Using the obtained potential difference, the resistance value was obtained from Ohm's law. The results are shown in Table 2.

(Water absorption)
From the conductive double-sided pressure-sensitive adhesive tapes obtained in Examples and Comparative Examples, a measurement sample of 50 mm width × 25 mm length was cut out and the mass of each sample was measured. The sample was immersed in water at 23 ° C. for 24 hours, and then the sample was taken out from the water. Water droplets on the surface of the sample taken out were wiped off, and then the mass of the sample was measured. The water absorption was determined as {(W2-W1) / W1} × 100 (%). W1 is the mass of the sample before immersion, and W2 is the mass of the sample after immersion. The results are shown in Table 2.

(Adhesive force)
A measurement sample having a width of 20 mm was cut out from the conductive double-sided adhesive tape obtained in Examples and Comparative Examples. The pressure-sensitive adhesive surface of one of the conductive pressure-sensitive adhesive layers included in the sample is made to reciprocate once a roller with a weight of 2.0 kg and a width of 30 mm with respect to a SUS plate (SUS304 plate) in an atmosphere of 23 ° C. and 60% RH. Pasted together. Note that the release liner is still attached to the adhesive surface of the other conductive adhesive layer. After leaving at room temperature (23 ° C., 60% RH) for 30 minutes, a tensile tester is used to perform a 180 ° peel test at a pulling speed of 300 mm / min in accordance with JIS Z 0237, and peel adhesion ( N / 20 mm). The results are shown in Table 2.

(Corrosion resistance)
The conductive double-sided pressure-sensitive adhesive tapes obtained in Examples and Comparative Examples were cut into a size of 20 mm in width and 20 mm in length to obtain test pieces. One surface (adhesive surface on one side) of the obtained test piece was bonded to a copper foil (thickness: 80 μm), and then stored for 5 days in an atmosphere of 60 ° C. and 95% RH. Then, the test piece was peeled off from the copper foil, and the presence or absence of corrosion was confirmed by visually observing the copper foil (the surface on which the test piece was bonded). When corrosion was not observed, it was judged as good (symbol ○), and when corrosion was observed, it was judged as defective (symbol x). The results are shown in Table 2.

(Step following capability)
As shown in FIG. 3, an adhesive tape 10 (manufactured by Nitto Denko Corporation, trade name “NO.31B”) having a length of 50 mm × width of 20 mm × thickness of 53 μm is pasted on a glass plate (soda lime glass) 9. Together, a step of 53 μm was produced. A conductive double-sided adhesive tape 11 (length 50 mm × width 20 mm) as a measurement sample was attached to the step using a hand roller (width 30 mm). After being left for 24 hours in an environment of 23 ° C. and 60% RH, the floating distance at the step portion 12 (the distance from the step edge to the tape adhesion point) was measured. When the floating distance was 1 mm or less, the step following ability was good (symbol ◯), and when it exceeded 1 mm, the step following ability was poor (symbol x). The results are shown in Table 2.

(Storage modulus (23 ° C))
The conductive double-sided pressure-sensitive adhesive tapes obtained in Examples and Comparative Examples were punched out to a diameter of 7.9 mm and used as measurement samples. Using a dynamic viscoelasticity measuring device (product name “ARES” manufactured by Rheometric Co., Ltd.), dynamic viscoelasticity measurement was performed under the following conditions, and storage elastic modulus G ′ at a temperature condition of 23 ° C. was measured. The results are shown in Table 2.
Apparatus: ARES (Advanced Rheometric Expansion System) manufactured by Rheometric Scientific
Frequency: 1Hz
Temperature: -40-100 ° C
Temperature rise: 5 ° C / min Strain: 1%

(Storage modulus (25 ° C))
The elastic modulus of the conductive double-sided pressure-sensitive adhesive tapes obtained in Examples and Comparative Examples was measured in the same manner as in the above-described temperature condition of 23 ° C. except that the temperature condition was changed to 25 ° C. The results are shown in Table 2.

(Storage modulus (70 ° C))
The elastic modulus of the conductive double-sided pressure-sensitive adhesive tapes obtained in Examples and Comparative Examples was measured in the same manner as in the above-described temperature condition of 23 ° C. except that the temperature condition was changed to 70 ° C. The results are shown in Table 2.

  In Table 2, “impossible to measure” indicates a case where the measurement sample could not be produced without the conductive adhesive layer being adhered to the adherend. In Table 2, “non-conducting” indicates a case where no conducting is performed. In Table 2, the part indicated by the symbol “*” indicates that evaluation has not been performed.

  As shown in Table 2, it was confirmed that the conductive double-sided adhesive tapes of Examples 1 to 6 had a resistance value of 2.6Ω or less and had good conductivity. In particular, it was confirmed that the conductive double-sided pressure-sensitive adhesive tapes of Examples 1 to 4 and 6 had a resistance value of 0.7Ω or less and had good conductivity. When the resistance value is 3.0Ω or less, it can be said that the film has good conductivity, and when the resistance value is 0.8Ω or less, it can be said that the film has particularly excellent conductivity.

  Moreover, it was confirmed that the electroconductive double-sided adhesive tapes of Examples 1 to 6 have a water absorption rate of 1.0% or less and have corrosion resistance. In addition, it can be said that it is the especially outstanding corrosion resistance as a water absorption is 1.5% or less.

  In addition, it was confirmed that the conductive double-sided pressure-sensitive adhesive tapes of Examples 1 to 6 had an adhesive strength (adhesive strength) of 14 N / 20 mm or more and had excellent adhesive strength (adhesive strength). In addition, when adhesive force (adhesive force) is 14 N / 20mm or more, it can be said that it has favorable adhesive force (adhesive force).

  Moreover, it was confirmed that the electroconductive double-sided adhesive tape of Examples 1-6 was equipped with favorable level | step difference followable | trackability. In addition, in evaluation of level | step difference followability, the floating distance of Examples 1-5 is shorter than Example 6, and the electroconductive double-sided adhesive tape of Examples 1-5 is compared with the electroconductive double-sided adhesive tape of Example 6. Therefore, it was excellent in step following ability.

  DESCRIPTION OF SYMBOLS 1 ... Conductive double-sided adhesive tape, 2 ... Conductive base material, 3 ... Conductive adhesive layer, 4 ... Glass plate (soda lime glass), 5 ... Copper foil, 6 ... Insulating tape, 7 ... Measurement sample (copper foil) Attached conductive double-sided pressure-sensitive adhesive tape), 8 ... bonded portion (within dotted line), 9 ... glass plate (soda lime glass), 10 ... adhesive tape, 11 ... measurement sample (conductive double-sided pressure-sensitive adhesive tape), 12 ... stepped portion

Claims (8)

  A conductive double-sided pressure-sensitive adhesive tape comprising a conductive pressure-sensitive adhesive layer containing conductive particles and an acrylic polymer and having a water absorption of 2% or less.   The conductive double-sided pressure-sensitive adhesive tape according to claim 1, wherein the acrylic polymer contains 0.01 to 2 mass% of a structural unit derived from a hydroxyl group-containing monomer.   The conductive double-sided pressure-sensitive adhesive tape according to claim 1 or 2, wherein the conductive particles are contained in an amount of 0.8 to 4% by volume in the conductive pressure-sensitive adhesive layer.   4. The conductive double-sided pressure-sensitive adhesive tape according to claim 1, wherein a thickness t of the conductive pressure-sensitive adhesive layer is 7 μm to 190 μm. 5. The conductive double-sided pressure-sensitive adhesive tape according to claim 1, wherein the conductive particles have an average particle diameter d ₅₀ (μm) of 0.10 μm to 190 μm. The conductive double-sided pressure-sensitive adhesive tape according to claim 1, wherein the conductive particles have an electric resistance value of 1.0 × 10 ⁻⁸ Ωm to 10.0 × 10 ⁻⁸ Ωm.   The conductive double-sided pressure-sensitive adhesive tape according to any one of claims 1 to 6, wherein the acrylic polymer contains 85 to 98 mass% of a structural unit derived from a (meth) acrylic acid alkyl ester. The value of the ratio (t / d ₅₀ ) between the thickness t (μm) of the conductive adhesive layer and the average particle diameter d ₅₀ (μm) of the conductive particles is in the range of 1 or more and 19 or less. The electroconductive double-sided adhesive tape as described in any one of 1-7.

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