Electrically releasable pressure-sensitive adhesive sheet, joint, and method for separating joint

Abstract

To provide an electrically peelable type adhesive sheet in which corrosion of a conductive layer in an electrode contact portion is prevented or suppressed.SOLUTION: An electrically peelable type adhesive sheet includes: an energization substrate having a conductive layer; a first adhesive layer composed of an electrically peelable adhesive agent formed on the conductive layer of the energization substrate; a second adhesive layer formed on a face opposite to the first adhesive layer of the energization substrate; and an electrode contact portion being a portion on which an adherend is not adhered at least on one face. The face on which an adherend is not adhered in the electrode contact portion has a portion where the conductive layer is not exposed in at least a part thereof.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to an electrically releasable pressure-sensitive adhesive sheet, a bonded body, and a method for separating the bonded body. [Background technology]

[0002] In electronic component manufacturing processes, etc., there is an increasing demand for rework to improve yields and recycling, such as disassembling and recovering components after use. To meet these demands, double-sided PSA sheets that have a certain level of adhesive strength and releasability are sometimes used to join components in electronic component manufacturing processes, etc.

[0003] As a double-sided pressure-sensitive adhesive sheet that achieves both adhesive strength and releasability, a pressure-sensitive adhesive sheet (electrically peelable pressure-sensitive adhesive sheet) having an electrically peelable pressure-sensitive adhesive layer made of an electrically peelable pressure-sensitive adhesive composition that peels off when a voltage is applied to the adhesive layer is known (Patent Document 1). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] International Publication No. 2017 / 064925 Summary of the Invention [Problem to be solved by the invention]

[0005] As shown in FIG. 1, an electrically releasing pressure-sensitive adhesive sheet 1 typically has a portion (electrode contact portion 4) that is not used for bonding adherends 2 and 3 together. An electrode is brought into contact with this electrode contact portion 4, and a voltage is applied to the electrically releasing pressure-sensitive adhesive layer to perform electrical peeling. FIG. 2 shows an enlarged side view of the periphery of the electrode contact portion 4 in FIG. 1. Typically, at the electrode contact portion 4, the conductive layer 6a of the substrate 6 is exposed so that an electrode can be brought into contact with the conductive layer 6a. By bringing an electrode into contact with the exposed conductive layer 6a, or the adherend 2 attached to the electrically releasing pressure-sensitive adhesive layer 5 side, and applying a voltage to the electrically releasing pressure-sensitive adhesive layer 5, the adhesive strength of the electrically releasing pressure-sensitive adhesive layer 5 is weakened, allowing for easy peeling.

[0006] However, there was a problem in that the exposed conductive layer 6a in this electrode contact portion 4 corroded when exposed to the outside air, making it impossible to apply voltage to the electrically peelable adhesive layer 5 and making electrical peeling impossible.

[0007] The present invention has been devised under these circumstances, and an object of the present invention is to provide an electrically peelable pressure-sensitive adhesive sheet in which corrosion of the conductive layer in the electrode contact area is suppressed or prevented. Another object of the present invention is to provide a bonded body having good electrical peeling properties and a method for separating such a bonded body. [Means for solving the problem]

[0008] As a result of extensive research, the present inventors have found that the above object can be achieved by an electrically peelable pressure-sensitive adhesive sheet or bonded body having a specific configuration.

[0009] The first electrically peelable adhesive sheet of the present invention, which solves the above-mentioned problems, is an electrically peelable adhesive sheet comprising an electrically conductive substrate having a conductive layer, a first adhesive layer consisting of an electrically peelable adhesive formed on the conductive layer of the electrically conductive substrate, and a second adhesive layer formed on the surface of the electrically conductive substrate opposite the first adhesive layer, and has an electrode contact portion on at least one surface which is a portion to which an adherend is not attached, and the surface of the electrode contact portion to which an adherend is not attached has at least a portion where the conductive layer is not exposed. In one embodiment of the first electrically peelable pressure-sensitive adhesive sheet of the present invention, the conductive layer may not be exposed over the entire surface of the electrode contact portion where the adherend is not attached. In one embodiment of the first electrically peelable pressure-sensitive adhesive sheet of the present invention, the surface of the electrode contact portion to which the adherend is not attached may be the surface on the first pressure-sensitive adhesive layer side, and the unexposed portion of the conductive layer may be covered by the first pressure-sensitive adhesive layer. In one embodiment of the first electrically peelable pressure-sensitive adhesive sheet of the present invention, the conductive substrate may further include a coating layer, and the unexposed portion of the conductive layer may be covered with the coating layer.

[0010] The second electrically peelable adhesive sheet of the present invention is an electrically peelable adhesive sheet comprising an electrically conductive substrate having a conductive layer, a first adhesive layer consisting of an electrically peelable adhesive formed on the conductive layer of the electrically conductive substrate, and a second adhesive layer formed on the surface of the electrically conductive substrate opposite to the first adhesive layer, wherein the conductive layer is not exposed over the entire surface facing the first adhesive layer or the entire surface facing the second adhesive layer.

[0011] The first bonded structure of the present invention is a bonded structure comprising: an electrically peeling adhesive sheet having an electrically conductive substrate with a conductive layer; a first adhesive layer made of an electrically peeling adhesive formed on the conductive layer of the electrically conductive substrate; and a second adhesive layer formed on the surface of the electrically conductive substrate opposite the first adhesive layer; a first adherend attached to the first adhesive layer of the electrically peeling adhesive sheet; and a second adherend attached to the second adhesive layer of the electrically peeling adhesive sheet, wherein at least the portion of the first adherend to which the first adhesive layer is attached is electrically conductive, and the electrically peeling adhesive sheet has an electrode contact portion on at least one surface where an adherend is not attached, and the surface of the electrode contact portion where the adherend is not attached has at least a portion where the electrically conductive layer is not exposed. In one embodiment of the first bonded body of the present invention, the conductive layer does not have to be exposed over the entire surface of the electrode contact portion where the adherend is not attached. In one embodiment of the first bonded body of the present invention, the surface of the electrode contact portion to which the adherend is not attached may be the surface on the first pressure-sensitive adhesive layer side, and the unexposed portion of the conductive layer may be covered with the first pressure-sensitive adhesive layer. In one embodiment of the first bonded body of the present invention, the current-carrying substrate may further include a coating layer, and the unexposed portion of the conductive layer may be covered with the coating layer.

[0012] The first bonded body separation method of the present invention is a method for separating the above-mentioned first bonded body, and includes contacting the electrode with the conductive layer by penetrating the layer covering the conductive layer in a portion of the electrode contact portion where the conductive layer is not exposed on the surface to which the adherend is not attached, and applying a voltage to the first pressure-sensitive adhesive layer.

[0013] The second bonded structure of the present invention is a bonded structure comprising an electrically releasing adhesive sheet having an electrically conducting substrate with a conductive layer, a first adhesive layer made of an electrically releasing adhesive formed on the conductive layer of the electrically conducting substrate, and a second adhesive layer formed on the surface of the electrically conducting substrate opposite the first adhesive layer, a first adherend attached to the first adhesive layer of the electrically releasing adhesive sheet, and a second adherend attached to the second adhesive layer of the electrically releasing adhesive sheet, wherein at least the portion of the first adherend where the first adhesive layer is attached is electrically conductive, and the first adherend is attached to the entire surface of the electrically releasing adhesive sheet facing the first adhesive layer, and the second adherend is attached to the entire surface of the electrically releasing adhesive sheet facing the second adhesive layer.

[0014] The second method for separating a bonded body of the present invention is a method for separating the second bonded body described above, which comprises penetrating the first adherend or the second adherend with an electrode to bring the electrode into contact with the conductive layer, and applying a voltage to the first pressure-sensitive adhesive layer.

[0015] The third bonded body of the present invention is a bonded body comprising an electrically peeling adhesive sheet comprising an electrically conductive substrate having conductive layers on both sides of a first adhesive layer made of an electrically peeling adhesive, and a second adhesive layer formed on the side of the electrically conductive substrate opposite the first adhesive layer, a first adherend attached to one of the second adhesive layers of the electrically peeling adhesive sheet, and a second adherend attached to the other second adhesive layer of the electrically peeling adhesive sheet, wherein the electrically peeling adhesive sheet has an electrode contact portion on at least one side where an adherend is not attached, and the side of the electrode contact portion where the adherend is not attached has at least a portion where the conductive layer is not exposed.

[0016] The third aspect of the present invention of The method for separating the conjugate is the same as that described above. 3 The method for separating the bonded body of the above includes penetrating the first adherend or the second adherend with an electrode to contact at least one of the conductive layers, and applying a voltage to the first pressure-sensitive adhesive layer. [Effects of the Invention]

[0017] In the electrically releasable pressure-sensitive adhesive sheet of the present invention, corrosion of the conductive layer at the electrode contact portion is suppressed or prevented, and the bonded structure of the present invention has good electrical releasability. [Brief explanation of the drawings]

[0018] [Figure 1] FIG. 1 is a schematic perspective view of a bonded structure in which adherends are bonded together with an electrically peelable pressure-sensitive adhesive sheet. [Figure 2] FIG. 2 is a schematic side view showing an enlarged view of the periphery of an electrode contact portion of a conventional electrically peelable pressure-sensitive adhesive sheet. [Figure 3] FIG. 3 is a schematic side view showing an enlarged view of the periphery of an electrode contact portion in a bonded body in which adherends are bonded with an electrically peelable pressure-sensitive adhesive sheet according to one embodiment of the present invention. [Figure 4] FIG. 4 is a schematic side view showing an enlarged view of the periphery of an electrode contact portion in a bonded body in which adherends are bonded with an electrically peeling pressure-sensitive adhesive sheet according to a modified embodiment of the present invention. [Figure 5] FIG. 5 is a schematic perspective view of a bonded body in which adherends are bonded together with an electrically peelable pressure-sensitive adhesive sheet according to a modified example of one embodiment of the present invention. [Figure 6] FIG. 6 is a schematic side view showing an enlarged view of the periphery of an electrode contact portion in a bonded body in which adherends are bonded with an electrically peelable pressure-sensitive adhesive sheet according to a modified embodiment of the present invention. [Figure 7] FIG. 7 is a schematic side view showing an enlarged view of the periphery of an electrode contact portion in a bonded body in which adherends are bonded with an electrically peeling pressure-sensitive adhesive sheet according to a modified embodiment of the present invention. [Figure 8] FIG. 8 is a schematic side view showing an enlarged view of the periphery of an electrode contact portion in a bonded body in which adherends are bonded with an electrically peelable pressure-sensitive adhesive sheet according to a modified embodiment of the present invention. [Figure 9] FIG. 9 is a schematic side view showing an enlarged view of the periphery of an electrode contact portion in a bonded body in which adherends are bonded with an electrically peeling pressure-sensitive adhesive sheet according to a modified embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0019] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The following describes in detail the preferred embodiments of the present invention, but the present invention is not limited to the following preferred embodiments.

[0020] [Adhesive sheet] Figure 3 shows an enlarged side view of the area around the electrode contact portion 14 in a bonded structure in which adherends (a first adherend 15 and a second adherend 16) are bonded together using the electrically peeling adhesive sheet 10 of this embodiment (hereinafter also simply referred to as "adhesive sheet 10"). The adhesive sheet 10 of this embodiment comprises an electrically conductive substrate 12 having a conductive layer 12a, a first adhesive layer 11 made of an electrically peelable adhesive formed on the conductive layer 12a of the electrically conductive substrate 12, and a second adhesive layer 13 formed on the surface of the electrically conductive substrate 12 opposite to the first adhesive layer 11. The adhesive sheet 10 of this embodiment also comprises an electrode contact portion 14 on at least one surface, which is a portion to which an adherend will not be attached, and the surface of the electrode contact portion 14 to which an adherend will not be attached (the surface on the side of the first adhesive layer 11 in the example shown in FIG. 3) has a portion in which the electrically conductive layer 12a is not exposed.

[0021] (First adhesive layer) The first pressure-sensitive adhesive layer 11 is a pressure-sensitive adhesive layer made of an electrically peelable pressure-sensitive adhesive (electrically peelable pressure-sensitive adhesive layer), and contains a polymer as a pressure-sensitive adhesive and an electrolyte.

[0022] Examples of the polymer contained in the first pressure-sensitive adhesive layer 11 include acrylic polymers, rubber polymers, vinyl alkyl ether polymers, silicone polymers, polyester polymers, polyamide polymers, urethane polymers, fluorine-containing polymers, and epoxy polymers. The first pressure-sensitive adhesive layer 11 may contain only one type of polymer, or may contain two or more types of polymers. From the viewpoint of cost reduction and realization of high productivity, it is preferable to contain an acrylic polymer. An acrylic polymer is a polymer containing monomer units derived from an alkyl acrylate ester and / or an alkyl methacrylate ester as the main monomer units that are the most abundant in terms of mass ratio. Hereinafter, "(meth)acrylic" represents "acrylic" and / or "methacrylic".

[0023] When the first pressure-sensitive adhesive layer 11 contains an acrylic polymer, the acrylic polymer preferably contains a monomer unit derived from a (meth)acrylic acid alkyl ester having an alkyl group having 1 to 14 carbon atoms. Examples of the (meth)acrylic acid alkyl ester include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, isopropyl (meth)acrylate, n-butyl (meth)acrylate, sec-butyl (meth)acrylate, 1,3-dimethylbutyl acrylate, pentyl (meth)acrylate, isopentyl (meth)acrylate, hexyl (meth)acrylate, 2-ethylbutyl (meth)acrylate, heptyl (meth)acrylate, n-octyl (meth)acrylate, isooctyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, n-nonyl (meth)acrylate, isononyl (meth)acrylate, n-decyl (meth)acrylate, isodecyl (meth)acrylate, n-dodecyl (meth)acrylate, n-tridecyl (meth)acrylate, and n-tetradecyl (meth)acrylate. Among these, n-butyl (meth)acrylate, sec-butyl (meth)acrylate, n-octyl (meth)acrylate, isooctyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, n-nonyl (meth)acrylate, and isononyl (meth)acrylate are preferred. One type of (meth)acrylic acid alkyl ester may be used, or two or more types of (meth)acrylic acid alkyl esters may be used.

[0024] The proportion of monomer units derived from a (meth)acrylic acid alkyl ester having an alkyl group with 1 to 14 carbon atoms in the acrylic polymer is preferably 50% by mass or more, more preferably 60% by mass or more, more preferably 70% by mass or more, and more preferably 80% by mass or more, from the viewpoint of realizing high adhesive strength for the first pressure-sensitive adhesive layer 11. That is, the proportion of a (meth)acrylic acid alkyl ester having an alkyl group with 1 to 14 carbon atoms in the total amount of raw material monomers for forming the acrylic polymer is preferably 50% by mass or more, more preferably 60% by mass or more, more preferably 70% by mass or more, and more preferably 80% by mass or more, from the viewpoint of realizing high adhesive strength for the first pressure-sensitive adhesive layer 11.

[0025] When the first pressure-sensitive adhesive layer 11 contains an acrylic polymer, the acrylic polymer preferably contains a monomer unit derived from a polar group-containing monomer, from the viewpoint of realizing high adhesive strength for the first pressure-sensitive adhesive layer 11. Examples of the polar group-containing monomer include a carboxyl group-containing monomer, a methoxy group-containing monomer, a hydroxyl group-containing monomer, and a vinyl group-containing monomer. Contains Monomers are included.

[0026] Examples of carboxyl group-containing monomers include acrylic acid, methacrylic acid, itaconic acid, maleic acid, fumaric acid, crotonic acid, isocrotonic acid, carboxyethyl (meth)acrylate, and carboxypentyl (meth)acrylate. Among these, acrylic acid and methacrylic acid are preferred. One type of carboxyl group-containing monomer may be used, or two or more types of carboxyl group-containing monomers may be used.

[0027] An example of a methoxy group-containing monomer is 2-methoxyethyl acrylate.

[0028] Examples of hydroxyl group-containing monomers include 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, 6-hydroxyhexyl (meth)acrylate, 8-hydroxyoctyl (meth)acrylate, 10-hydroxydecyl (meth)acrylate, 12-hydroxylauryl (meth)acrylate, (4-hydroxymethylcyclohexyl)methyl acrylate, N-methylol (meth)acrylamide, vinyl alcohol, allyl alcohol, 2-hydroxyethyl vinyl ether, 4-hydroxybutyl vinyl ether, and diethylene glycol monovinyl ether. Among these, 2-hydroxyethyl (meth)acrylate is preferred. Furthermore, one type of hydroxyl group-containing monomer may be used, or two or more types of hydroxyl group-containing monomers may be used.

[0029] Examples of vinyl group-containing monomers include vinyl acetate, vinyl propionate, and vinyl laurate. Of these, vinyl acetate is preferred. One type of vinyl group-containing monomer may be used, or two or more types of vinyl group-containing monomers may be used.

[0030] The proportion of the monomer unit derived from the polar group-containing monomer in the acrylic polymer is preferably 0.1% by mass or more, from the viewpoint of ensuring cohesive strength in the first pressure-sensitive adhesive layer 11 and preventing adhesive residue on the adherend surface after peeling off the first pressure-sensitive adhesive layer 11. That is, from the viewpoint of ensuring cohesive strength and preventing adhesive residue, the proportion of the polar group-containing monomer in the total amount of raw material monomers for forming the acrylic polymer is preferably 0.1% by mass or more. Furthermore, from the viewpoint of appropriately expressing the properties attributable to the monomer unit derived from the (meth)acrylic acid alkyl ester having an alkyl group having 1 to 14 carbon atoms in the acrylic polymer, the proportion of the polar group-containing monomer in the total amount of raw material monomers for forming the acrylic polymer is preferably 30% by mass or less. That is, from the viewpoint of expressing the properties, the proportion of the polar group-containing monomer in the total amount of raw material monomers for forming the acrylic polymer is preferably 30% by mass or less.

[0031] The method for polymerizing the above-mentioned monomers to obtain an acrylic polymer is not particularly limited, and known methods can be used. Examples of polymerization techniques include solution polymerization, emulsion polymerization, bulk polymerization, and suspension polymerization.

[0032] From the viewpoint of realizing sufficient adhesive strength in the first pressure-sensitive adhesive layer 11, the polymer content in the first pressure-sensitive adhesive layer 11 is preferably 70% by mass or more, more preferably 80% by mass or more, more preferably 85% by mass or more, and more preferably 90% by mass or more.

[0033] The electrolyte contained in the first pressure-sensitive adhesive layer 11 is a substance that can be ionized into anions and cations, and examples of such electrolytes include ionic liquids, alkali metal salts, and alkaline earth metal salts. From the viewpoint of realizing good electro-separability in the first pressure-sensitive adhesive layer 11, an ionic liquid is preferred as the electrolyte contained in the first pressure-sensitive adhesive layer 11. An ionic liquid is a salt that is liquid at room temperature (about 25°C) and contains anions and cations.

[0034] When the first pressure-sensitive adhesive layer 11 contains an ionic liquid, the anion of the ionic liquid is (FSO2)2N - , (CF3SO2)2N - , (CF3CF2SO2)2N - , (CF3SO2)3C - , Br - , AlCl4 - , Al2Cl7 - , NO3 - , BF4 - , PF6 - , CH3COO - , CF3COO - , CF3CF2CF2COO - , CF3SO3 - , CF3(CF2)3SO3 - , AsF6 - , SbF6 - and F(HF) n - It is preferable that the anion contains at least one selected from the group consisting of (FSO2)2N - [Bis(fluorosulfonyl)imide anion], and (CF3SO2)2N - [Bis(trifluoromethanesulfonyl)imide anion] is preferred because it is chemically stable and is suitable for realizing electrical peelability of the first pressure-sensitive adhesive layer 11.

[0035] When the first adhesive layer 11 contains an ionic liquid, it is preferable that the cation of the ionic liquid contains at least one selected from the group consisting of imidazolium-based cations, pyridinium-based cations, pyrrolidinium-based cations, and ammonium-based cations.

[0036] Examples of imidazolium cations include 1-methylimidazolium cation, 1-ethyl-3-methylimidazolium cation, 1-propyl-3-methylimidazolium cation, 1-butyl-3-methylimidazolium cation, 1-pentyl-3-methylimidazolium cation, 1-hexyl-3-methylimidazolium cation, 1-heptyl-3-methylimidazolium cation, 1-octyl-3-methylimidazolium cation, 1-nonyl-3-methylimidazolium cation, 1-undecyl-3-methylimidazolium cation, and 1-dodecyl-3-methylimidazolium cation. cation, 1-tridecyl-3-methylimidazolium cation, 1-tetradecyl-3-methylimidazolium cation, 1-pentadecyl-3-methylimidazolium cation, 1-hexadecyl-3-methylimidazolium cation, 1-heptadecyl-3-methylimidazolium cation, 1-octadecyl-3-methylimidazolium cation, 1-undecyl-3-methylimidazolium cation, 1-benzyl-3-methylimidazolium cation, 1-butyl-2,3-dimethylimidazolium cation, and 1,3-bis(dodecyl)imidazolium cation.

[0037] Examples of pyridinium-based cations include 1-butylpyridinium cation, 1-hexylpyridinium cation, 1-butyl-3-methylpyridinium cation, 1-butyl-4-methylpyridinium cation, and 1-octyl-4-methylpyridinium cation.

[0038] Examples of pyrrolidinium-based cations include 1-ethyl-1-methylpyrrolidinium cation and 1-butyl-1-methylpyrrolidinium cation.

[0039] Examples of ammonium cations include tetraethylammonium cation, tetrabutylammonium cation, methyltrioctylammonium cation, tetradecylammonium cation, and tetradecylammonium cation. LIncluded are trihexylammonium cation, glycidyltrimethylammonium cation, and trimethylaminoethyl acrylate cation.

[0040] As the ionic liquid in the first pressure-sensitive adhesive layer 11, an ionic liquid containing the above-mentioned (FSO2)2N-[bis(fluorosulfonyl)imide anion] and a cation having a molecular weight of 160 or less is particularly preferred, from the viewpoint of utilizing the high diffusibility of cations to realize high electro-separability in the first pressure-sensitive adhesive layer 11. Examples of cations having a molecular weight of 160 or less include 1-methylimidazolium cation, 1-ethyl-3-methylimidazolium cation, 1-propyl-3-methylimidazolium cation, 1-butyl-3-methylimidazolium cation, 1-pentyl-3-methylimidazolium cation, 1-butylpyridinium cation, 1-hexylpyridinium cation, 1-butyl-3-methylpyridinium cation, 1-butyl-4-methylpyridinium cation, 1-ethyl-1-methylpyrrolidinium cation, 1-butyl-1-methylpyrrolidinium cation, tetraethylammonium cation, glycidyltrimethylammonium cation, and trimethylaminoethyl acrylate cation.

[0041] Commercially available ionic liquids contained in the first adhesive layer 11 include, for example, "ELEXCEL AS-110," "ELEXCEL MP-442," "ELEXCEL IL-210," "ELEXCEL MP-471," "ELEXCEL MP-456," and "ELEXCEL AS-804," manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.

[0042] Examples of alkali metal salts include LiCl, Li2SO4, LiBF4, LiPF6, LiClO4, LiAsF6, LiCF3SO3, LiN(SO2CF3)2, LiN(SO2C2F5)2, LiC(SO2CF3)3, NaCl, Na2SO4, NaBF4, NaPF6, NaClO4, NaAsF6, NaCF3SO3, NaN(SO2CF3)2, NaN(SO2C2F5)2, NaC(SO2CF3)3, KCl, K2SO4, KBF4, KPF6, KClO4, KAsF6, KCF3SO3, KN(SO2CF3)2, KN(SO2C2F5)2 and KC(SO2CF3)3.

[0043] The content of the ionic liquid in the first pressure-sensitive adhesive layer 11 is, for example, 0.1 parts by mass or more per 100 parts by mass of the polymer in the first pressure-sensitive adhesive layer 11 in order to impart electro-releasability to the first pressure-sensitive adhesive layer 11. From the viewpoint of realizing better electro-releasability, the content is preferably 0.5 parts by mass or more, more preferably 0.6 parts by mass or more, even more preferably 0.8 parts by mass or more, particularly preferably 1.0 parts by mass or more, and most preferably 1.5 parts by mass or more. From the viewpoint of realizing a good balance between good adhesive strength and electro-releasability for the first pressure-sensitive adhesive layer 11, the content of the ionic liquid in the first pressure-sensitive adhesive layer 11 is preferably 30 parts by mass or less, more preferably 20 parts by mass or less, even more preferably 15 parts by mass or less, particularly preferably 10 parts by mass or less, and most preferably 5 parts by mass or less per 100 parts by mass of the polymer in the first pressure-sensitive adhesive layer 11.

[0044] The first pressure-sensitive adhesive layer 11 may contain other components within a range that does not impair the effects of the present invention. Examples of such components include tackifiers, silane coupling agents, colorants, pigments, dyes, surface lubricants, leveling agents, softeners, antioxidants, antiaging agents, light stabilizers, polymerization inhibitors, inorganic or organic fillers, metal powders, particulate materials, corrosion inhibitors, and foil-like materials. Various additives for resin compositions can be used. The content of these components is determined depending on the intended use within a range that does not impair the effects of the present invention. For example, the content is 10 parts by mass or less per 100 parts by mass of the polymer.

[0045] The thickness of the first pressure-sensitive adhesive layer 11 is not particularly limited, but is preferably 1 μm or more, more preferably 3 μm or more, even more preferably 5 μm or more, and particularly preferably 8 μm or more from the viewpoint of realizing good adhesiveness in the first pressure-sensitive adhesive layer 11. Furthermore, from the viewpoint of reducing the voltage applied when peeling off the adherend, the thickness is preferably 1000 μm or less, more preferably 500 μm or less, even more preferably 100 μm or less, and particularly preferably 30 μm or less.

[0046] (Second adhesive layer) Second adhesive layer 13 is the second adhesive layer 13 The second adhesive layer contains a polymer for exhibiting adhesiveness. 13 The components and their contents are the same as those of the first adhesive layer, except for the electrolyte. 11 The components and their contents are the same as those described above. Second adhesive layer 13 The thickness of the second adhesive is not particularly limited. 13 From the viewpoint of realizing good adhesiveness in the above, the thickness is preferably 1 μm or more, more preferably 3 μm or more, even more preferably 5 μm or more, and particularly preferably 8 μm or more. The thickness is also preferably 1000 μm or less, more preferably 500 μm or less, and even more preferably 100 μm or less.

[0047] (Base material for energizing) The conductive substrate is not particularly limited as long as it has a conductive layer. The conductive substrate may have a laminated structure having a conductive layer 12a and a substrate layer 12b, as in the example shown in FIG. 3, or a single-layer structure consisting of only a conductive layer 22a, as in the modified example shown in FIG. 4. The conductive substrate may further include a coating layer, or may have a laminated structure having a coating layer 12c, a conductive layer 12a, and a substrate layer 12b, as in the modified example shown in FIG. 7. In the modified example shown in FIG. 7, the unexposed portion of the conductive layer 12a may be covered with the coating layer 12c. The conductive substrate may also have a laminated structure having a coating layer and a conductive layer. The thickness of the conductive base material is not particularly limited, but in any configuration, it is preferably, for example, 10 μm or more, more preferably 12 μm or more, even more preferably 25 μm or more, and is preferably, for example, 1000 μm or less, more preferably 500 μm or less, even more preferably 300 μm or less, and particularly preferably 100 μm or less.

[0048] In the laminated conductive substrate 12 shown in Fig. 3, the substrate layer 12b functions as a support and may be, for example, a plastic substrate, a fiber substrate, a paper substrate, or a laminate thereof. The substrate layer 12b may be a single layer or multiple layers. Furthermore, the substrate layer 12b may be subjected to various treatments, such as a back surface treatment, an antistatic treatment, and a primer treatment, as needed. The thickness of the base layer 12b is not particularly limited, but is preferably 10 μm or more, more preferably 12 μm or more, and even more preferably 25 μm or more, and is preferably 1000 μm or less, more preferably 500 μm or less, even more preferably 300 μm or less, and particularly preferably 100 μm or less.

[0049] The conductive layer 12a is a layer having conductivity and is made of a conductive material such as a metal (e.g., aluminum, copper, iron, tin, gold, alloys thereof, etc.), a conductive polymer, a conductive metal oxide (e.g., ITO, etc.), or carbon. The conductive layer 12a can be formed by, for example, plating, chemical vapor deposition, or sputtering. The thickness of the conductive layer 12a is not particularly limited, but is preferably 0.001 μm or more, more preferably 0.01 μm or more, even more preferably 0.03 μm or more, particularly preferably 0.05 μm or more, and is preferably 1000 μm or less, more preferably 500 μm or less, even more preferably 300 μm or less, particularly preferably 50 μm or less, and most preferably 10 μm or less.

[0050] The coating layer 12c is a layer containing a resin or an inorganic substance as a main component, and can be formed from a resin composition containing a resin component as a main component or a composition made of an inorganic substance. When the coating layer 12c is mainly composed of a resin, the resin components constituting the coating layer 12c (resin coating layer) may include, for example, epoxy-based resins, polyester-based resins, acrylic-based resins, or urethane-based resins, which may be used alone or as a mixture.

[0051] The resin composition forming the coating layer 12c (resin coating layer) containing a resin as a main component preferably contains the above-mentioned resin component (polymer) as a main component. The polymer content in the resin composition of this embodiment is preferably 50% by mass or more and 99.9% by mass or less relative to the total amount of the resin composition (100% by mass), with the upper limit being more preferably 99.5% by mass, and even more preferably 99% by mass, and the lower limit being more preferably 60% by mass, and even more preferably 70% by mass.

[0052] The resin composition may further contain a curing agent, which may be a commonly used curing agent such as an isocyanate-based curing agent, an epoxy-based curing agent, or a melamine-based curing agent.

[0053] The resin composition of this embodiment may also contain various additives such as fillers, plasticizers, antioxidants, antioxidants, pigments (dyes), flame retardants, solvents, surfactants (leveling agents), rust inhibitors, corrosion inhibitors, and antistatic agents. The total content of these components is not particularly limited as long as the effects of the present invention are achieved, but is preferably 0.01 parts by mass or more and 20 parts by mass or less, more preferably 10 parts by mass or less, and even more preferably 5 parts by mass or less, per 100 parts by mass of the resin.

[0054] Examples of fillers include silica, iron oxide, zinc oxide, aluminum oxide, titanium oxide, barium oxide, magnesium oxide, calcium carbonate, magnesium carbonate, zinc carbonate, pyrophyllite clay, kaolin clay, and calcined clay. The plasticizer may be any known or commonly used plasticizer used in general resin compositions, etc., and examples thereof include oils such as paraffin oil and process oil, liquid rubbers such as liquid polyisoprene, liquid polybutadiene, and liquid ethylene-propylene rubber, tetrahydrophthalic acid, azelaic acid, benzoic acid, phthalic acid, trimellitic acid, pyromellitic acid, adipic acid, sebacic acid, fumaric acid, maleic acid, itaconic acid, citric acid, and derivatives thereof, dioctyl phthalate (DOP), dibutyl phthalate (DBP), dioctyl adipate, diisononyl adipate (DINA), and isodecyl succinate. Examples of antioxidants include hindered phenol compounds, and aliphatic and aromatic hindered amine compounds. Examples of antioxidants include butylhydroxytoluene (BHT) and butylhydroxyanisole (BHA). Examples of pigments include inorganic pigments such as titanium dioxide, zinc oxide, ultramarine, red iron oxide, lithopone, lead, cadmium, iron, cobalt, aluminum, hydrochlorides, and sulfates, and organic pigments such as azo pigments and copper phthalocyanine pigments. Examples of the rust inhibitor include zinc phosphate, tannic acid derivatives, phosphoric acid esters, basic sulfonates, and various rust-preventive pigments. Examples of corrosion inhibitors include carbodiimide compounds, adsorption inhibitors, and chelating-type metal deactivators. For example, those described in JP 2019-059908 A can be used. Antistatic agents generally include quaternary ammonium salts, or hydrophilic compounds such as polyglycolic acid and ethylene oxide derivatives.

[0055] The form of the resin composition is not particularly limited, and may be, for example, an aqueous resin composition, a solvent-based resin composition, a hot-melt resin composition, an active energy ray-curable resin composition, etc. Here, the aqueous resin composition refers to a resin composition in a form containing a coating layer-forming component in a solvent (aqueous solvent) containing water as the main component, and is a concept that encompasses a water-dispersed resin composition in which the components constituting the coating layer are dispersed in water, and a water-soluble resin composition in which the components constituting the coating layer are dissolved in water.

[0056] The coating layer 12c (resin coating layer) containing a resin as its main component can be formed by applying a resin composition using a known technique such as gravure coating, reverse roll coating, roll coating, dip coating, or comma coating, drying it, and then curing it by irradiating it with ultraviolet light, electron beams, or the like, as necessary.

[0057] The thickness of the coating layer 12c (resin coating layer) containing a resin as a main component is preferably 10 nm or more and 5000 nm or less from the viewpoint of electrical peeling properties. The upper limit of the thickness of the coating layer 12c (resin coating layer) is more preferably 2000 nm, and even more preferably 1000 nm. n The upper limit is more preferably 15 nm, even more preferably 20 nm, and particularly preferably 30 nm.

[0058] When the coating layer 12c is mainly composed of an inorganic substance, examples of the inorganic substance constituting the coating layer 12c (inorganic coating layer) include metals, metal alloys, metal oxides, and metal nitrides. Examples of metals include silicon, aluminum, nickel, chromium, tin, gold, silver, platinum, zinc, titanium, tungsten, zirconium, and palladium. As the inorganic substance, Al2O3, Ni, NiCr, or inorganic nitrides or inorganic oxides of non-stoichiometric composition such as SiNx or SiOx are preferable.

[0059] The coating layer 12c (inorganic coating layer) containing an inorganic substance as a main component can be formed by sputtering, vapor deposition, or the like.

[0060] From the viewpoint of electrical peelability, the thickness of the coating layer 12c (inorganic coating layer) mainly composed of an inorganic substance is preferably 1 nm or more and 1000 nm or less. The upper limit of the thickness of the coating layer 12c (inorganic coating layer) is more preferably 700 nm, even more preferably 500 nm, and particularly preferably 200 nm, and the lower limit is more preferably 1 nm, even more preferably 20 nm, and particularly preferably 50 nm.

[0061] In the modification shown in FIG. 4, the single-layered current-carrying substrate 22 is made up of only a conductive layer 22a, and functions as both a support and a conductor.

[0062] (electrode contact part) The pressure-sensitive adhesive sheet 10 of this embodiment has an electrode contact portion 14 on at least one surface, which is a portion to which no adherend is attached. The shape of the electrode contact portion is not particularly limited. For example, it may be in the shape of an extended tab, as in the conventional example shown in Fig. 1. Furthermore, when an adherend with a hole is attached, as shown in Fig. 5, the adherend will not be attached to the hole, and the portion where the adherend is not attached becomes electrode contact portion 14. The pressure-sensitive adhesive sheet 10 of this embodiment has a portion where the conductive layer 12a is not exposed in at least a part of the surface of the electrode contact portion 14 to which the adherend is not attached (hereinafter also referred to as the "electrode contact surface"). The unexposed portion of the conductive layer 12a may be covered with a first adhesive layer 11 as shown in FIG. Furthermore, the unexposed portion of the conductive layer 12a may be covered with a coating layer 12c as shown in FIG. Since corrosion of the conductive layer 12a is unlikely to occur in the unexposed portions of the conductive layer 12a, the risk of electrical peeling becoming impossible due to corrosion of the conductive layer 12a is reduced in the pressure-sensitive adhesive sheet 10 of this embodiment. Note that a method of electrical peeling in which an electrode is brought into contact with the unexposed conductive layer 12a will be described later.

[0063] In the pressure-sensitive adhesive sheet 10 of this embodiment, it is sufficient that the conductive layer 12a is not exposed on at least a portion of the surface of the electrode contact portion 14 to which the adherend is not attached. However, to further suppress corrosion of the conductive layer 12a, it is preferable that the ratio of the area of ​​the portion where the conductive layer 12a is not exposed to the area of ​​the electrode contact surface is large. The ratio of the area of ​​the portion where the conductive layer 12a is not exposed to the area of ​​the electrode contact surface of the electrode contact portion 14 is preferably 30% or more, more preferably 50% or more, even more preferably 80% or more, and most preferably 100%. In other words, it is preferable that the conductive layer 12a is not exposed over the entire electrode contact surface of the electrode contact portion 14. Furthermore, in the pressure-sensitive adhesive sheet 10 of this embodiment, it is particularly preferable from the viewpoint of corrosion prevention that the conductive layer 12a is not exposed on the entire surface on the first pressure-sensitive adhesive layer 11 side and the entire surface on the second pressure-sensitive adhesive layer 13 side.

[0064] In the pressure-sensitive adhesive sheet 10 of the example shown in Fig. 3, the surface of the electrode contact portion 14 facing the first pressure-sensitive adhesive layer 11 is the electrode contact surface, i.e., no adherend is attached to the surface facing the first pressure-sensitive adhesive layer 11, but as shown in Fig. 6, the surface facing the second pressure-sensitive adhesive layer 13 may be the electrode contact surface. In other words, in the electrode contact portion 14, no adherend may be attached to the surface facing the second pressure-sensitive adhesive layer 13. Although it is not necessary for an adherend to be attached to both the surface of the electrode contact portion facing the first pressure-sensitive adhesive layer 11 and the surface of the second pressure-sensitive adhesive layer 13, in this case, the electrode contact portion 14 becomes unstable, making it difficult to bring the electrode into contact with the electrode and to perform electrical peeling. Therefore, as in the examples shown in Fig. 3 and Fig. 6, it is preferable that an adherend be attached to either the surface of the electrode contact portion 14 facing the first pressure-sensitive adhesive layer 11 or the surface of the second pressure-sensitive adhesive layer 13.

[0065] Furthermore, particularly in the adhesive sheet 10 of this embodiment, it is preferable that the surface of the electrode contact portion 14 facing the first adhesive layer does not have an adherend, i.e., the surface of the electrode contact portion 14 facing the first adhesive layer is an electrode contact surface. When the electrode is brought into contact with the conductive layer at the electrode contact portion, the electrode penetrates the layer covering the conductive layer 12a, for example, and is brought into contact with the conductive layer 12a, as will be described in detail later. In this case, if the surface on the side of the first adhesive layer 11 is the electrode contact surface as shown in Figure 3, the electrode can be brought into contact with the conductive layer 12a by penetrating only the first adhesive layer 11 covering the conductive layer 12a, making electrical peeling relatively easy. On the other hand, when the surface on the side of the second pressure-sensitive adhesive layer 13 is the electrode contact surface as shown in Fig. 6, the electrode must penetrate at least the base material layer 12b in order to contact the conductive layer 12a. Because the base material layer 12b is usually relatively thick and strong, penetrating it with an electrode is not as easy as penetrating the first pressure-sensitive adhesive layer 11 with an electrode. Furthermore, if an electrode that has penetrated the base material layer 12b also penetrates the conductive layer 12a and the first pressure-sensitive adhesive layer 11 and comes into contact with the first adherend 15, it will no longer be possible to apply a voltage to the first pressure-sensitive adhesive layer, and therefore precise control is required when penetrating the base material layer 12b with the electrode. The same applies when the current-carrying substrate 22 has a single-layer structure made of a conductive layer 22a, as in the modified example shown in Fig. 4. In this case, if the surface on the second pressure-sensitive adhesive layer side is the electrode contact surface, it is not necessary to penetrate the substrate layer when bringing the electrode into contact with the conductive layer 22a, but fine control is still required.

[0066] Separators (release liners) may be provided on the surfaces of the first pressure-sensitive adhesive layer 11 and the second pressure-sensitive adhesive layer 13 of the pressure-sensitive adhesive sheet 10 of this embodiment. The separators are elements for protecting the first pressure-sensitive adhesive layer 11 and the second pressure-sensitive adhesive layer 13 of the pressure-sensitive adhesive sheet 10 so that they are not exposed, and are peeled off from the pressure-sensitive adhesive sheet 10 when the pressure-sensitive adhesive sheet 10 is attached to an adherend. The pressure-sensitive adhesive sheet 10 may be sandwiched between two separators, or the pressure-sensitive adhesive sheet 10 may be wound into a roll together with the separators so that the pressure-sensitive adhesive sheets 10 and the separators are arranged alternately. Examples of separators include substrates having a release treatment layer, low-adhesion substrates made of fluoropolymers, and low-adhesion substrates made of non-polar polymers. The surface of the separator may be subjected to a release treatment, an antifouling treatment, or an antistatic treatment. The thickness of the separator is, for example, 5 to 200 μm.

[0067] The electrically peeling pressure-sensitive adhesive sheet according to the embodiment of the present invention may be a double-sided electrically peeling pressure-sensitive adhesive sheet, as in the modified example shown in Fig. 8. The electrically peeling pressure-sensitive adhesive sheet shown in Fig. 8 has an electrode contact area 14 on at least one surface, which is a portion to which an adherend is not attached, and has a laminated structure in which an electric conductive base material 12 and a second pressure-sensitive adhesive layer 13 are laminated on both surfaces of a first pressure-sensitive adhesive layer 11. In a modified example shown in FIG. 8 , the double-sided electrically peeling pressure-sensitive adhesive sheet may be attached to a first adherend 15 on one side of the second pressure-sensitive adhesive layer 13, and to a second adherend 16 on the other side of the second pressure-sensitive adhesive layer 13. Furthermore, as shown in FIG. 8 , the double-sided electrically peeling pressure-sensitive adhesive sheet according to an embodiment of the present invention may have an exposed extension 17 that extends beyond one of the current-carrying substrate 12 and the adherend 15 in the surface direction. In this configuration, electrical connection between one terminal of a device to which voltage is applied and the current-carrying substrate 12 is easily achieved via the extension 17. Furthermore, the extension direction of the extension 17 from one of the current-carrying substrate 12 and the adherend 15 is different from the extension direction of the electrode contact portion 14, and in this embodiment, is the opposite direction. This configuration facilitates appropriate application of voltage to the double-sided electrically peeling pressure-sensitive adhesive sheet by a voltage application device, for example, while avoiding short-circuiting between device terminals. 8, the unexposed portion of the conductive layer 12a may be covered with the first pressure-sensitive adhesive layer 11. Furthermore, the conductive layer 12a in the extension portion 17 is preferably not exposed, and may be covered with the first pressure-sensitive adhesive layer 11.

[0068] Furthermore, the electrically peeling pressure-sensitive adhesive sheet according to the embodiment of the present invention may be a double-sided electrically peeling pressure-sensitive adhesive sheet, as in the modified example shown in Fig. 9. The double-sided electrically peeling pressure-sensitive adhesive sheet shown in Fig. 9 has a laminated structure in which a conductive substrate 12 and a second pressure-sensitive adhesive layer 13 are laminated on both sides of a first pressure-sensitive adhesive layer 11. In the modified example shown in Figure 9, the double-sided electrically peelable adhesive sheet may be attached to a first adherend 15 on one side of the second adhesive layer 13, and to a second adherend 16 on the other side of the second adhesive layer 13. The conductive substrate may have a laminated structure having a coating layer 12c, a conductive layer 12a, and a substrate layer 12b, as in the modified example shown in Fig. 9. The conductive substrate may also have a laminated structure having a coating layer and a conductive layer. The electrically peelable pressure-sensitive adhesive sheet in the modified example shown in Fig. 9 may have an extension 17 that extends beyond one of the conductive substrates 12 and the adherend 15 in the surface extension direction and is exposed, similar to the electrically peelable pressure-sensitive adhesive sheet shown in Fig. 8. The unexposed portion of the conductive layer 12a may be covered with a coating layer 12c as shown in Fig. 9. Furthermore, the conductive layer 12a in the extension portion 17 is preferably not exposed, and may be covered with a coating layer 12c.

[0069] (Adhesive strength of adhesive sheet) From the viewpoint of realizing good adhesive strength, the 180° peel adhesive strength (against SUS304 plate, tensile speed 300 mm / min, peel temperature 23°C) of the first adhesive layer 11 of the adhesive sheet 10 is preferably 1.0 N / 10 mm or more, more preferably 2.0 N / 10 mm or more, and even more preferably 3.0 N / 10 mm or more. There is no particular upper limit, but it is usually 20 N / 10 mm or less. From the same viewpoint, the 180° peel adhesive strength (against SUS304 plate, tensile speed 300 mm / min, peel temperature 23°C) of second adhesive layer 13 of adhesive sheet 10 is preferably 1.0 N / 10 mm or more, more preferably 2.0 N / 10 mm or more, and even more preferably 3.0 N / 10 mm or more. There is no particular upper limit, but it is usually 20 N / 10 mm or less. The 180° peel adhesive strength of the adhesive sheet 10 can be measured in accordance with JIS Z 0237, for example, as follows. First, for the adhesive sheet 10 with separators on both sides, one separator is peeled off, and then a polyethylene terephthalate (PET) film with a thickness of 50 μm is attached to the exposed adhesive surface. of The adhesive sheet 10 is then attached to the adhesive sheet 10, forming a backing. A test piece (10 mm wide x 100 mm long) is then cut out from the backed adhesive sheet 10. The other separator is then peeled off from the test piece, and the test piece is attached to a stainless steel plate (SUS304) as the adherend. A 2 kg roller is then rolled back and forth once to press the test piece and the adherend together. After allowing to stand for 30 minutes, the 180° peel adhesive strength (tensile speed: 300 mm / min, peel temperature: 23°C) is measured using a peel tester (product name "YSP Variable Angle Peel Measuring Instrument", manufactured by Asahi Seiko Co., Ltd.).

[0070] Furthermore, from the viewpoint of realizing good electrical peeling properties, the 180° peel adhesive strength of the first pressure-sensitive adhesive layer 11 of the pressure-sensitive adhesive sheet 10 after voltage application (against a SUS304 plate, a tensile speed of 300 mm / min, a peel temperature of 23°C) is preferably 1.0 N / 10 mm or less, more preferably 0.5 N / 10 mm or less, and even more preferably 0.2 N / 10 mm or less. There is no particular lower limit, but it is usually 0.01 N / 10 mm or more. The 180° peel adhesive strength after voltage application is the 180° peel adhesive strength (tensile speed: 300 mm / min, peel temperature: 23°C) measured using a peel tester after pressing the test piece and the adherend together as described above and leaving them to stand for 30 minutes, then applying a voltage of 10 V for 10 seconds and then keeping the voltage applied.

[0071] Furthermore, it is preferable that the 180° peel adhesion strength of the first adhesive layer 11 after voltage application (hereinafter also referred to as "adhesion strength after voltage application") is sufficiently low compared to the 180° peel adhesion strength of the first adhesive layer 11 (hereinafter also referred to as "initial adhesion strength"), and the adhesion strength reduction rate calculated by the following formula (C) is preferably 60% or more, more preferably 70% or more, and even more preferably 80% or more. Adhesion strength reduction rate (%) = {1 - (adhesion strength after voltage application / initial adhesion strength)} x 100 (C)

[0072] (Method of manufacturing pressure-sensitive adhesive sheet) In manufacturing the pressure-sensitive adhesive sheet 10, for example, first, a pressure-sensitive adhesive composition (first composition) for forming the first pressure-sensitive adhesive layer 11 and a pressure-sensitive adhesive composition (second composition) for forming the second pressure-sensitive adhesive layer 13 are prepared. Next, the first composition is applied to the conductive layer 12 of the conductive substrate 12. a and drying the coated layer. This forms the first pressure-sensitive adhesive layer 11. Next, the second composition is coated on the surface of the conductive substrate 12 opposite to the first pressure-sensitive adhesive layer 11 and dried. This forms the second pressure-sensitive adhesive layer 13. For example, the pressure-sensitive adhesive sheet 10 can be produced in this manner.

[0073] Alternatively, the pressure-sensitive adhesive sheet 10 may be produced by a so-called transfer method. Specifically, first, the first pressure-sensitive adhesive layer 11 and the second pressure-sensitive adhesive layer 13 are each formed on a separator (release liner). The first pressure-sensitive adhesive layer 11 is formed by applying the first composition for forming the first pressure-sensitive adhesive layer 11 to the release-treated surface of a predetermined separator to form a coating film, and then drying the coating film. The second pressure-sensitive adhesive layer 13 is formed by applying the second composition for forming the second pressure-sensitive adhesive layer 13 to the release-treated surface of a predetermined separator to form a coating film, and then drying the coating film. Next, the first pressure-sensitive adhesive layer 11 with the separator is bonded to the conductive layer 12a of the current-carrying substrate 12. Next, the second pressure-sensitive adhesive layer 13 with the separator is bonded to the surface of the current-carrying substrate 12 opposite the first pressure-sensitive adhesive layer 11. For example, the pressure-sensitive adhesive sheet 10 can be produced in this manner.

[0074] In the modification shown in Fig. 8, for example, the surface of the first adhesive layer 11 of the adhesive sheet 10 produced by the above method is attached to the surface of the conductive layer 12a of the current-carrying substrate 12. Next, a second adhesive sheet 10 including a separator is attached. 2 Adhesive layer 13 is attached to the surface of the base layer 12b side of the conductive base material 12. In this way, for example, the double-sided electrically peelable pressure-sensitive adhesive sheet shown in FIG. In the modified example shown in Fig. 9, similarly to the double-sided electrically peeling pressure-sensitive adhesive sheet shown in Fig. 8, for example, the surface of the first pressure-sensitive adhesive layer 11 of the electrically peeling pressure-sensitive adhesive sheet shown in Fig. 7 is attached to the surface of the coating layer 12c of the conductive substrate 12 including the coating layer 12c. 2 Adhesive layer 13 is attached to the surface of the base layer 12b side of the conductive base material 12. In this way, for example, the double-sided electrically peelable pressure-sensitive adhesive sheet shown in FIG.

[0075] [Conjugate and method for separating the conjugate] First Embodiment Next, a first embodiment of the bonded body and a method for separating the bonded body will be described. The bonded structure of this embodiment comprises an electrically peeling adhesive sheet having an electrically conductive substrate with a conductive layer, a first adhesive layer made of an electrically peeling adhesive formed on the conductive layer of the electrically conductive substrate, and a second adhesive layer formed on the surface of the electrically conductive substrate opposite the first adhesive layer, a first adherend attached to the first adhesive layer of the electrically peeling adhesive sheet, and a second adherend attached to the second adhesive layer of the electrically peeling adhesive sheet, wherein at least the portion of the first adherend to which the first adhesive layer is attached is electrically conductive, and the electrically peeling adhesive sheet has an electrode contact portion on at least one surface where an adherend is not attached, and the surface of the electrode contact portion where an adherend is not attached has at least a portion where the electrically conductive layer is not exposed. That is, the bonded body of this embodiment is a bonded body in which a first adherend and a second adherend are bonded together by the above-mentioned pressure-sensitive adhesive sheet.

[0076] When separating the bonded structure of this embodiment, electrodes are brought into contact with the first adherend and the conductive layer, and a voltage is applied to the first pressure-sensitive adhesive layer to reduce the adhesive strength of the first pressure-sensitive adhesive layer, thereby peeling the first adherend from the first pressure-sensitive adhesive layer. When the electrodes are brought into contact with the conductive layer, the electrodes penetrate the layer covering the conductive layer at the electrode contact surface in the electrode contact portion, thereby contacting the conductive layer. That is, for example, in the example shown in FIG. 3, the electrodes penetrate the first pressure-sensitive adhesive layer 11 and contact the conductive layer 12a. In addition, in the example shown in FIG. 6, the electrodes penetrate the second pressure-sensitive adhesive layer 13 and the base layer 12b and contact the conductive layer 12a.

[0077] The materials of the first adherend and the second adherend are not particularly limited, as long as at least the portion of the first adherend to which the first pressure-sensitive adhesive layer is attached is conductive, and the portion to be in contact with the electrode is conductive, and these portions are electrically conductive.

[0078] The voltage applied to the first pressure-sensitive adhesive layer during separation of the bonded body is preferably 1 V or more, more preferably 3 V or more, more preferably 6 V or more, and even more preferably 10 V or more, and is preferably 500 V or less, more preferably 300 V or less, even more preferably 100 V or less, and particularly preferably 50 V or less. This range is preferable because it allows the joining body to be separated efficiently. For example, this range makes it possible to use readily available power sources such as dry batteries as the power source for the voltage application device. Furthermore, the time for applying voltage to the first adhesive layer is preferably 300 seconds or less, more preferably 180 seconds or less, even more preferably 120 seconds or less, even more preferably 60 seconds or less, and particularly preferably 30 seconds or less. Such a range is preferable in terms of improving the efficiency of the work of separating the bonded body.

[0079] <Second embodiment> Next, a second embodiment of the bonded body and a method for separating the bonded body will be described. The bonded structure of this embodiment comprises an electrically peeling adhesive sheet having an electrically conductive substrate with a conductive layer, a first adhesive layer made of an electrically peeling adhesive formed on the conductive layer of the electrically conductive substrate, and a second adhesive layer formed on the surface of the electrically conductive substrate opposite the first adhesive layer, a first adherend attached to the first adhesive layer of the electrically peeling adhesive sheet, and a second adherend attached to the second adhesive layer of the electrically peeling adhesive sheet, wherein at least the portion of the first adherend where the first adhesive layer is attached is electrically conductive, and the first adherend is attached to the entire surface of the electrically peeling adhesive sheet facing the first adhesive layer, and the second adherend is attached to the entire surface of the electrically peeling adhesive sheet facing the second adhesive layer. That is, in the bonded body of this embodiment, the conductive layer is covered by the adherend and is not exposed to the outside until immediately before electrical peeling, so corrosion of the conductive layer is suppressed.

[0080] When separating the bonded body of this embodiment, electrodes are brought into contact with the first adherend and the conductive layer, and a voltage is applied to the first pressure-sensitive adhesive layer to reduce the adhesive strength of the first pressure-sensitive adhesive layer, thereby peeling the first adherend from the first pressure-sensitive adhesive layer. When bringing the electrodes into contact with the conductive layer, the electrodes penetrate the first adherend or the second adherend and bring the electrodes into contact with the conductive layer.

[0081] The preferred ranges of the materials of the first and second adherends, the applied voltage, and the voltage application time are the same as those in the first embodiment.

[0082] <Third embodiment> Next, a third embodiment of the bonded body and a method for separating the bonded body will be described. The bonded structure of this embodiment comprises an electrically peelable adhesive sheet comprising an electrically conductive substrate having conductive layers on both sides of a first adhesive layer made of an electrically peelable adhesive, and a second adhesive layer formed on the side of the electrically conductive substrate opposite the first adhesive layer, a first adherend attached to one of the second adhesive layers of the electrically peelable adhesive sheet, and a second adherend attached to the other second adhesive layer of the electrically peelable adhesive sheet, wherein the electrically peelable adhesive sheet has an electrode contact portion on at least one side where an adherend is not attached, and the side of the electrode contact portion where an adherend is not attached has at least a portion where the conductive layer is not exposed. That is, in the bonded body of this embodiment, the conductive layer is covered by the adherend and is not exposed to the outside until immediately before electrical peeling, so corrosion of the conductive layer is suppressed.

[0083] When separating the bonded body of this embodiment, electrodes are brought into contact with the first adherend and the conductive layer, and a voltage is applied to the first pressure-sensitive adhesive layer to reduce the adhesive strength of the first pressure-sensitive adhesive layer, thereby peeling the first adherend from the first pressure-sensitive adhesive layer. When bringing the electrodes into contact with the conductive layer, the electrodes penetrate the first adherend or the second adherend and contact at least one of the conductive layers.

[0084] The preferred ranges of the materials of the first and second adherends, the applied voltage, and the voltage application time are the same as those in the first embodiment. [Example]

[0085] The present invention will be explained in more detail below with reference to examples, but the present invention is not limited to these examples.

[0086] (Preparation of acrylic polymer solution) Monomer components, n-butyl acrylate (BA): 87 parts by mass, 2-methoxyethyl acrylate (MEA): 10 parts by mass, acrylic acid (AA): 3 parts by mass, and polymerization solvent ethyl acetate: 150 parts by mass were charged into a separable flask and stirred for 1 hour while introducing nitrogen gas. After removing oxygen from the polymerization system in this way, 2,2'-azobisisobutyronitrile (AIBN): 0.2 parts by mass was added as a polymerization initiator, and the temperature was raised to 63 ° C. and reacted for 6 hours. Ethyl acetate was then added to obtain an acrylic polymer solution with a solids concentration of 40% by mass.

[0087] [Example 1] (Preparation of Electrically Peelable Adhesive Layer) 100 parts by mass of the acrylic polymer (solution) obtained above and 0.4 parts by mass of the crosslinking agent V-05 were mixed. Mass part 4 parts by mass of ionic liquid AS-110, additives (3 parts by mass of adsorptive inhibitor AMINE O, 0.3 parts by mass of Irgacor DSSG, and 0.8 parts by mass of chelating-type metal deactivator Irgamet 30), and ethyl acetate were added and stirred and mixed to obtain an electrically peelable pressure-sensitive adhesive composition (solution) adjusted to a solids concentration of 25% by mass. The obtained electrically peelable pressure-sensitive adhesive composition (solution) was applied to a uniform thickness using an applicator onto the release-treated surface of a polyethylene terephthalate separator (trade name "MRF38", manufactured by Mitsubishi Plastics, Inc.). Next, the coating was dried by heating at 150°C for 3 minutes, and the release-treated surface of the polyethylene terephthalate separator (trade name "MRE38", manufactured by Mitsubishi Plastics, Inc.) was laminated onto the pressure-sensitive adhesive using a hand roller to obtain a 50 μm-thick electrically peelable pressure-sensitive adhesive layer.

[0088] The abbreviations for the ionic liquid, crosslinker, adsorptive inhibitor, and chelating metal deactivator in Table 1 are as follows:

[0089] (ionic liquid) AS-110: Cation: 1-ethyl-3-methylimidazolium cation, Anion: bis(fluorosulfonyl)imide anion, trade name "Elexcel AS-110", manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd. (Crosslinking agent) V-05: Polycarbodiimide resin, product name "Carbodilite V-05", manufactured by Nisshinbo Chemical Inc. (adsorption inhibitor) AMINE O: 2-(8-heptadecen-1-yl)-4,5-dihydro-1H-imidazole-1-ethanol, trade name "AMINE O", manufactured by BASF Japan Ltd. Irgacor DSSG: Sodium sebacate, product name "Irgacor DSSG", manufactured by BASF Japan Ltd. (Chelate-forming metal deactivator) Irgamet 30: N,N-bis(2-ethylhexyl)-[(1,2,4-triazol-1-yl)methyl]amine, trade name "Irgamet 30", manufactured by BASF Japan Ltd.

[0090] (Preparation of electrically peelable adhesive sheets) The polyethylene terephthalate separator (MRE38) from the obtained electrically peelable adhesive layer was peeled off, and the surface of the exposed electrically peelable adhesive layer was bonded to the conductive layer side of a metal layer-attached film (product name "Metal Me TS", manufactured by Toray Advanced Film Co., Ltd., thickness 50 μm), which is a laminate consisting of an electrically conductive layer (metal layer (aluminum vapor deposition layer)) and a supporting substrate (polyethylene terephthalate (PET)) laminated in this order, to produce an electrically peelable adhesive sheet.

[0091] (Preparation of junction) The polyethylene terephthalate separator (MRF38) was peeled off from the electrically peelable pressure-sensitive adhesive sheet, and a stainless steel plate (SUS316, size: 30 mm × 120 mm) was attached to the peeled surface as a conductive substrate, so that one end of the electrically peelable pressure-sensitive adhesive sheet protruded from the substrate by about 2 mm, as shown in Figure 3. The sheet was pressed back and forth once with a 2 kg roller and left for 30 minutes in an environment of 23°C, resulting in a bonded assembly in which the unexposed part of the conductive layer was covered with the electrically peelable pressure-sensitive adhesive layer.

[0092] [Example 2] An electrically peelable pressure-sensitive adhesive layer was prepared in the same manner as in Example 1. The polyethylene terephthalate separator (MRE38) from the obtained electrically peelable pressure-sensitive adhesive layer was peeled off, and the resin coating layer side of a film with a resin coating layer and a metal layer (conductive substrate) (product name "1005CR", manufactured by Toray Advanced Film Co., Ltd., thickness 12 μm), which is a laminate consisting of a resin coating layer (polyester resin layer), a conductive layer (metal layer (aluminum vapor deposition layer)), and a supporting substrate (PET) laminated in this order, was attached to the peeled surface so that one end of the laminate protruded from the electrically peelable pressure-sensitive adhesive layer by approximately 2 mm, as shown in Figure 7, to obtain an electrically peelable pressure-sensitive adhesive sheet. As the adherend, a stainless steel plate (SUS316, size: 30 mm x 120 mm) was prepared as a conductive adherend. The polyethylene terephthalate separator (MRF38) was peeled off from the electrically peelable pressure-sensitive adhesive sheet obtained above, and the electrically conductive adherend described above was attached to the surface of the peeled electrically peelable pressure-sensitive adhesive layer side, pressed back and forth once with a 2 kg roller, and left to stand in an environment of 23°C for 30 minutes, to obtain a bonded body in which the unexposed part of the electrically conductive layer was covered with a resin coating layer.

[0093] [Example 3] A metal layered film (product name "Metal Me TS", manufactured by Toray Advanced Film Co., Ltd., thickness 50 μm) was prepared, which is a laminate consisting of a conductive layer (metal layer (aluminum vapor deposition layer)) and a supporting substrate (polyethylene terephthalate (PET)) laminated in this order. Next, a Si target (AC: 40 kHz) was attached to an AC sputtering device, and sputtering was performed while introducing O2 gas and N2 gas, forming a 50 nm inorganic coating layer (SiN x A SiN layer was formed on the substrate A. x The temperature of the metal layered film was set to -8°C when the layer was formed. The polyethylene terephthalate separator (MRE38) was peeled off from the electrically peelable adhesive layer prepared in the same manner as in Example 1, and the inorganic coating layer side of the above-mentioned substrate A was attached to the surface of the peeled electrically peelable adhesive layer so that one end of the substrate A protruded from the electrically peelable adhesive layer by about 2 mm, as shown in Figure 7, to obtain an electrically peelable adhesive sheet. In the same manner as in Example 2, a conductive adherend was attached to the electrically peelable pressure-sensitive adhesive sheet, and a bonded body was obtained in which the unexposed portion of the conductive layer was covered with an inorganic coating layer.

[0094] [Example 4] A metal layered film (product name "Metal Me TS", manufactured by Toray Advanced Film Co., Ltd., thickness 50 μm) was prepared, which is a laminate consisting of a conductive layer (metal layer (aluminum vapor deposition layer)) and a supporting substrate (polyethylene terephthalate (PET)) laminated in this order. Next, a nickel (Ni) target was attached to an AC sputtering device (AC: 40 kHz), and sputtering was performed while introducing Ar gas to form a 100 nm thick metal layer (Ni layer) on the ITO layer, producing substrate B. The temperature of the substrate film when forming the Ni layer was set to -8°C. An electrically peelable pressure-sensitive adhesive sheet and an assembly of Example 4 were obtained in the same manner as in Example 3, except that the substrate A was changed to the substrate B.

[0095] [Examples 5 and 6] The same procedures were carried out in Example 3 except that the thickness of the inorganic coating layer was changed to 100 nm and 200 nm. 5 and the electrically peelable pressure-sensitive adhesive sheet and bonded body of Example 6 were obtained.

[0096] [Comparative Example 1] An electrically peelable pressure-sensitive adhesive layer was prepared in the same manner as in Example 1, the polyethylene terephthalate separator (MRE38) of the obtained electrically peelable pressure-sensitive adhesive layer was peeled off, and a stainless steel plate (SUS316, size: 30 mm × 120 mm) was attached to the peeled surface as a conductive adherend to obtain a laminate. As the substrate, a metal layered film (product name "Metal Me S", manufactured by Toray Advanced Film Co., Ltd., thickness 50 μm) was prepared, which is a laminate consisting of a conductive layer (metal layer (aluminum vapor deposition layer)) and a supporting substrate (polyethylene terephthalate (PET)) laminated in this order. The polyethylene terephthalate separator (MRF38) was peeled off from the laminate obtained above, and the conductive layer side of the substrate was attached to the peeled surface of the electrically releasable pressure-sensitive adhesive layer side, as shown in Figure 2, so that one end of the substrate protruded from the laminate by about 2 mm.The substrate was then pressed back and forth once with a 2 kg roller and left in an environment of 23°C for 30 minutes, and a bonded body was obtained in which the surface of the electrode contact portion to which the adherend was not attached had at least a portion where the conductive layer was not exposed.

[0097] <Corrosion evaluation> The bonded bodies obtained in Examples 1 to 6 and Comparative Example 1 were stored for one week in a thermo-hygrostat set at a temperature of 60°C and a humidity of 90%, and then the presence or absence of corrosion of the conductive layer was evaluated visually.

[0098] The results obtained for Examples 1 to 4 and Comparative Example 1 are shown in Table 1. For Examples 5 and 6, the result of the question regarding the presence or absence of corrosion was "no."

[0099] [Table 1] [Explanation of symbols]

[0100] 1 electrically peelable adhesive sheet; 2, 3 adherend; 4 electrode contact portion; 5 electrically peelable adhesive layer; 6 substrate; 6a conductive layer; 6b substrate layer; 7 adhesive layer; 10 electrically peelable adhesive sheet; 11 first adhesive layer; 12 conductive substrate; 12a conductive layer; 12b substrate layer; 12c coating layer; 13 second adhesive layer; 14 electrode contact portion; 15 first adherend; 16 second adherend; 17 extension portion; 20 electrically peelable adhesive sheet; 21 first adhesive layer; 22 conductive substrate; 22a conductive layer; 23 second adhesive layer; 24 electrode contact portion; 25 first adherend; 26 second adherend.

Claims

1. a conductive substrate having a conductive layer; a first pressure-sensitive adhesive layer formed on the conductive layer of the conductive substrate and made of an electrically peelable pressure-sensitive adhesive; a second pressure-sensitive adhesive layer formed on a surface of the conductive substrate opposite to the first pressure-sensitive adhesive layer, the electrically peelable pressure-sensitive adhesive sheet has an electrode contact area on at least one surface, which is an area to which no adherend is attached; the conductive substrate further includes a coating layer containing a resin or an inorganic material as a main component, the surface of the electrode contact portion to which the adherend is not attached has at least a portion where the conductive layer is not exposed, The electrically peelable pressure-sensitive adhesive sheet, wherein the unexposed portion of the conductive layer is covered with the coating layer.

2. The electrically peelable pressure-sensitive adhesive sheet according to claim 1 , wherein the conductive layer is not exposed over the entire surface of the electrode contact portion on which the adherend is not attached.

3. a conductive substrate having a conductive layer; a first pressure-sensitive adhesive layer formed on the conductive layer of the conductive substrate and made of an electrically peelable pressure-sensitive adhesive; an electrically peelable pressure-sensitive adhesive sheet comprising a second pressure-sensitive adhesive layer formed on a surface of the conductive substrate opposite to the first pressure-sensitive adhesive layer; a first adherend attached to the first pressure-sensitive adhesive layer of the electrically peelable pressure-sensitive adhesive sheet; a second adherend attached to the second pressure-sensitive adhesive layer of the electrically peelable pressure-sensitive adhesive sheet, At least a portion of the first adherend to which the first pressure-sensitive adhesive layer is attached is electrically conductive; The electrically peelable pressure-sensitive adhesive sheet has an electrode contact portion on at least one surface thereof where an adherend is not attached, and the surface of the electrode contact portion where an adherend is not attached has at least a portion where the conductive layer is not exposed.

4. The bonded body according to claim 3 , wherein the conductive layer is not exposed over the entire surface of the electrode contact portion on which the adherend is not attached.

5. 5. The joined body according to claim 3, wherein in the electrode contact portion, a surface to which an adherend is not attached is a surface on the side of the first pressure-sensitive adhesive layer, and an unexposed portion of the conductive layer is covered with the first pressure-sensitive adhesive layer.

6. the conductive substrate further includes a coating layer containing a resin or an inorganic material as a main component, 5. The bonded body according to claim 3, wherein the unexposed portion of the conductive layer is covered with the coating layer.

7. 7. The method for separating a bonded body according to claim 3, comprising: bringing an electrode into contact with the conductive layer by penetrating a layer covering the conductive layer in a portion of the electrode contact portion on a surface to which an adherend is not attached and where the conductive layer is not exposed, and applying a voltage to the first pressure-sensitive adhesive layer.

8. a conductive substrate having conductive layers on both sides of a first pressure-sensitive adhesive layer made of an electrically peelable pressure-sensitive adhesive; an electrically peelable pressure-sensitive adhesive sheet comprising a second pressure-sensitive adhesive layer formed on a surface of the conductive substrate opposite to the first pressure-sensitive adhesive layer; a first adherend attached to one second pressure-sensitive adhesive layer of the electrically peelable pressure-sensitive adhesive sheet; a second adherend attached to the other second pressure-sensitive adhesive layer of the electrically peelable pressure-sensitive adhesive sheet, The electrically peelable pressure-sensitive adhesive sheet has an electrode contact portion on at least one surface thereof where an adherend is not attached, and the surface of the electrode contact portion where an adherend is not attached has at least a portion where the conductive layer is not exposed.

9. 9. The method for separating a bonded body according to claim 8, comprising: penetrating the first adherend or the second adherend with an electrode to bring the electrode into contact with at least one of the conductive layers, and applying a voltage to the first pressure-sensitive adhesive layer.

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