Electrically peelable type adhesive sheet, assembly and separation method of assembly

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 peelable pressure-sensitive adhesive sheet, a joint, and a method for separating the joint. [Background technology]

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

[0003] As a double-sided pressure-sensitive adhesive sheet that realizes 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 upon application of a voltage 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 peelable adhesive sheet 1 usually has a portion (electrode contact portion 4) that is not used for bonding adherends 2 and 3. An electrode is brought into contact with the electrode contact portion 4, and a voltage is applied to the electrically peelable 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. Usually, at the electrode contact portion 4, the conductive layer 6a is exposed so that an electrode can be brought into contact with the conductive layer 6a in the substrate 6. By bringing an electrode into contact with the exposed conductive layer 6a, the adherend 2 attached to the electrically peelable adhesive layer 5 side, and applying a voltage to the electrically peelable adhesive layer 5, the adhesive strength of the electrically peelable adhesive layer 5 is weakened, and peeling can be easily performed.

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

[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 structure having good electrical peelability and a method for separating such a bonded structure. [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 which is a portion to which an adherend is not attached on at least one surface, 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 does not have to be exposed over the entire surface of the electrode contact portion on which the adherend is not attached. In one embodiment of the first electrically peelable adhesive sheet of the present invention, the surface of the electrode contact portion to which the adherend is not attached is the surface on the first adhesive layer side, and the unexposed portion of the conductive layer may be covered by the first 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 and the entire surface facing the second adhesive layer.

[0011] The first bonded body of the present invention is a bonded body comprising an electrically peelable adhesive sheet comprising an electrically conductive base material having a conductive layer, a first adhesive layer consisting of an electrically peelable adhesive formed on the conductive layer of the electrically conductive base material, and a second adhesive layer formed on the surface of the electrically conductive base material opposite the first adhesive layer, a first adherend attached to the first adhesive layer of the electrically peelable adhesive sheet, and a second adherend attached to the second adhesive layer of the electrically peelable adhesive sheet, wherein at least a portion of the first adherend to which the first adhesive layer is attached is electrically conductive, the electrically peelable adhesive sheet has an electrode contact portion on at least one surface which is a portion to which an adherend is not attached, and at least a portion of the surface of the electrode contact portion to which an adherend is not attached has 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 to which 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 is 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 conductive base material 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, which comprises contacting the electrode with the conductive layer through a 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 body of the present invention is a bonded body comprising an electrically peelable adhesive sheet comprising an electrically conductive base material having a conductive layer, a first adhesive layer consisting of an electrically peelable adhesive formed on the conductive layer of the electrically conductive base material, and a second adhesive layer formed on the surface of the electrically conductive base material opposite the first adhesive layer, a first adherend attached to the first adhesive layer of the electrically peelable adhesive sheet, and a second adherend attached to the second adhesive layer of the electrically peelable adhesive sheet, wherein at least the portion of the first adherend to which the first adhesive layer is attached is conductive, and the first adherend is affixed to the entire surface of the electrically peelable adhesive sheet facing the first adhesive layer, and the second adherend is affixed to the entire surface of the electrically peelable 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 above-mentioned second bonded body, 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 peelable adhesive sheet comprising an electrically conductive base material 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 base material 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 at least one of the surfaces of the electrically peelable adhesive sheet has an electrode contact portion which is a portion to which an adherend is not attached, and 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.

[0016] A third method for separating a bonded body of the present invention is a method for separating the third bonded body described above, which comprises 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. Effect of the Invention

[0017] In the electrically peelable pressure-sensitive adhesive sheet of the present invention, corrosion of the conductive layer in the electrode contact area is suppressed or prevented, and the bonded structure of the present invention has good electrical peelability. [Brief description 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. [Diagram 2] FIG. 2 is a schematic side view showing an enlarged view of the periphery of an electrode contact portion in a conventional electrically peelable pressure-sensitive adhesive sheet. [Diagram 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 an adherend is 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 an adherend is bonded with an electrically peelable pressure-sensitive adhesive sheet according to a modified embodiment of the present invention. [Diagram 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 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 an adherend is 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 peelable 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 an adherend is 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 an adherend is bonded with an electrically peelable pressure-sensitive adhesive sheet according to a modified embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0019] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below with reference to the preferred embodiments. However, the present invention is not limited to the preferred embodiments described below.

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

[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, silicon polymers, polyester polymers, polyamide polymers, urethane polymers, fluorine 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 a monomer unit derived from an alkyl acrylate ester and / or an alkyl methacrylate ester as the main monomer unit that is 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. In addition, 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.

[0026] Examples of the carboxyl group-containing monomer 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. In addition, 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. In addition, 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. Also, 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 ratio of the monomer unit derived from the polar group-containing monomer in the above acrylic polymer is preferably 0.1% by mass or more from the viewpoint of ensuring the cohesive force 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, the ratio of the polar group-containing monomer in the total amount of raw material monomers for forming the above acrylic polymer is preferably 0.1% by mass or more from the viewpoint of ensuring the cohesive force and preventing adhesive residue. In addition, the ratio of the monomer unit derived from the polar group-containing monomer in the above acrylic polymer is preferably 30% by mass or less from the viewpoint of appropriately expressing the characteristics due to the monomer unit derived from the above (meth)acrylic acid alkyl ester having an alkyl group having 1 to 14 carbon atoms in the acrylic polymer. That is, the ratio of the polar group-containing monomer in the total amount of raw material monomers for forming the above acrylic polymer is preferably 30% by mass or less from the viewpoint of expressing the characteristics.

[0031] The method for obtaining an acrylic polymer by polymerizing the above-mentioned monomers is not particularly limited, and any known method can be used. Examples of the polymerization method 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 electrical peelability 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 achieving 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, 1-dodecyl-3-methylimidazolium cation, imidazolium 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 the 1-ethyl-1-methylpyrrolidinium cation and the 1-butyl-1-methylpyrrolidinium cation.

[0039] Examples of ammonium-based cations include tetraethylammonium cation, tetrabutylammonium cation, methyltrioctylammonium cation, tetradecyltrihexylammonium cation, glycidyltrimethylammonium cation, and trimethylaminoethylacrylate cation.

[0040] As the ionic liquid in the first pressure-sensitive adhesive layer 11, from the viewpoint of utilizing the high diffusivity of the cation to realize high electrical peelability 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 preferable. Examples of the cation 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 relative to 100 parts by mass of the polymer in the first pressure-sensitive adhesive layer 11 in order to impart electrical peelability to the first pressure-sensitive adhesive layer 11, and from the viewpoint of realizing better electrical peelability, it 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 electrical peelability 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 relative to 100 parts by mass of the polymer in the first pressure-sensitive adhesive layer 11.

[0044] The first 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 matter, corrosion inhibitors, and foil-like materials, and various additives in resin compositions can be used. The content of these components is determined within a range that does not impair the effects of the present invention depending on the purpose of use. For example, it is 10 parts by mass or less with respect to 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. Moreover, 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 pressure-sensitive adhesive layer 13 contains a polymer for imparting adhesiveness to second pressure-sensitive adhesive layer 13. The components contained in second pressure-sensitive adhesive layer 13 and their contents are the same as those described above for the components contained in first pressure-sensitive adhesive layer 11, except for the electrolyte. The thickness of the second pressure-sensitive adhesive layer 13 is not particularly limited, but from the viewpoint of realizing good adhesiveness in the second pressure-sensitive adhesive layer 13, it 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. Also, it is preferably 1000 μm or less, more preferably 500 μm or less, and even more preferably 100 μm or less.

[0047] (Base material for current-carrying) The conductive substrate is not particularly limited as long as it has a conductive layer. The conductive substrate may be a laminated structure having a conductive layer 12a and a substrate layer 12b as in the example shown in FIG. 3, or may be 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 be 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 portion where the conductive layer 12a is not exposed may be covered with the coating layer 12c. The conductive substrate may be 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, and 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 in the example shown in Fig. 3, the substrate layer 12b functions as a support, and is, 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. In addition, the substrate layer 12b may be subjected to various treatments such as a back surface treatment, an antistatic treatment, and an undercoat treatment, as necessary. 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 electrical 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, a plating method, a chemical vapor deposition method, or a sputtering method. 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, and 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 coat 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) include, for example, epoxy-based resins, polyester-based resins, acrylic-based resins, or urethane-based resins, which can be used alone or as a mixture.

[0051] The resin composition for 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 mass% or more and 99.9 mass% or less relative to the total amount of the resin composition (100 mass%), with the upper limit being more preferably 99.5 mass%, and even more preferably 99 mass%, and the lower limit being more preferably 60 mass%, and even more preferably 70 mass%.

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

[0053] The resin composition of the present 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, relative to 100 parts by mass of the resin.

[0054] Examples of the filler 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. As the plasticizer, a known and commonly used plasticizer used in general resin compositions and the like can be used, 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 the antioxidant include hindered phenol compounds, and aliphatic and aromatic hindered amine compounds. Examples of the antioxidant 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; azo pigments; and organic pigments such as copper phthalocyanine pigments. Examples of the rust inhibitor include zinc phosphate, tannic acid derivatives, phosphoric esters, basic sulfonates, and various rust inhibitor 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. As the antistatic agent, generally, a quaternary ammonium salt or a hydrophilic compound such as polyglycolic acid or an ethylene oxide derivative can be mentioned.

[0055] The form of the resin composition is not particularly limited, and may be, for example, a water-based resin composition, a solvent-based resin composition, a hot melt-type resin composition, an active energy ray curable resin composition, etc. Here, the water-based resin composition refers to a resin composition in a form containing a coating layer forming component in a solvent (water-based solvent) mainly composed of water, and is a concept that includes 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 by a known technique such as gravure coating, reverse roll coating, roll coating, dip coating, or comma coating, drying the composition, and then curing the composition by irradiating the composition with ultraviolet light, electron beams, or the like as necessary.

[0057] From the viewpoint of electrical peelability, the thickness of the coating layer 12c (resin coating layer) mainly made of resin is preferably 10 nm or more and 5000 nm or less. The upper limit of the thickness of the coating layer 12c (resin coating layer) is more preferably 2000 nm, further preferably 1000 nm, and particularly preferably 500 nm, and the lower limit is more preferably 15 nm, further 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 oxides having a 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 a sputtering method, a vapor deposition method, 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, further preferably 500 nm, and particularly preferably 200 nm, and the lower limit is more preferably 1 nm, further 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 both as a support and as a conductor.

[0062] (electrode contact part) The pressure-sensitive adhesive sheet 10 of this embodiment has, on at least one surface, an electrode contact portion 14 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. In addition, when an adherend having a hole is attached, for example, as shown in Fig. 5, the adherend is not attached to the portion with the hole, and the portion to which the adherend is not attached becomes the electrode contact portion 14. The pressure-sensitive adhesive sheet 10 of the present 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 an 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 the conductive layer is less likely to corrode in the unexposed portion of the conductive layer 12a, the risk of electrical peeling being impossible due to corrosion of the conductive layer 12a is suppressed in the pressure-sensitive adhesive sheet 10 of this embodiment. Note that a method of electrical peeling by bringing an electrode 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 part of the surface of the electrode contact portion 14 to which the adherend is not attached, but in order 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. In addition, in the pressure-sensitive adhesive sheet 10 of this embodiment, it is particularly preferable from the viewpoint of corrosion inhibition 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 example adhesive sheet 10 shown in Fig. 3, the surface of the electrode contact portion 14 facing the first adhesive layer 11 is the electrode contact surface, i.e., no adherend is attached to the surface facing the first adhesive layer 11, but the surface facing the second adhesive layer 13 may be the electrode contact surface as shown in Fig. 6. That is, in the electrode contact portion 14, an adherend does not have to be attached to the surface facing the second adhesive layer 13. It is not necessary for an adherend to be affixed 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, but in this case, the electrode contact portion 14 becomes unstable, making it difficult to bring the electrode into contact and difficult to perform electrical peeling. Therefore, as in the examples shown in Fig. 3 and Fig. 6, it is preferable that an adherend be affixed 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 a 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, when the surface on the side of the first adhesive layer 11 is an electrode contact surface as shown in FIG. 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, and therefore electrical peeling can be performed relatively easily. On the other hand, when the surface on the second adhesive layer 13 side is the electrode contact surface as shown in Fig. 6, in order to bring the electrode into contact with the conductive layer 12a, it is necessary to penetrate at least the base material layer 12b. Since the base material layer 12b is usually relatively thick and has high strength, penetrating it with an electrode is not as easy as penetrating the first adhesive layer 11 with an electrode. In addition, if an electrode that has penetrated the base material layer 12b also penetrates the conductive layer 12a and the first adhesive layer 11 and comes into contact with the first adherend 15, it becomes impossible to apply a voltage to the first adhesive layer, so fine control is required when penetrating the base material layer 12b with an 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, when the surface on the second adhesive layer side is the electrode contact surface, it is not necessary to penetrate the substrate layer when contacting the electrode with the conductive layer 22a, but fine control is still required.

[0066] In addition, a separator (release liner) may be provided on the surface of the first adhesive layer 11 and the second adhesive layer 13 of the adhesive sheet 10 of this embodiment. The separator is an element for protecting the first adhesive layer 11 and the second adhesive layer 13 of the adhesive sheet 10 so that they are not exposed, and is peeled off from the adhesive sheet 10 when the adhesive sheet 10 is attached to an adherend. The adhesive sheet 10 may be sandwiched between two separators, or the adhesive sheet 10 may be wound into a roll together with the separator so that the adhesive sheet 10 and the separator are alternately arranged. Examples of the separator include a substrate having a release treatment layer, a low-adhesion substrate made of a fluoropolymer, and a low-adhesion substrate made of a non-polar polymer. 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 peelable adhesive sheet according to the embodiment of the present invention may be a double-sided electrically peelable adhesive sheet, as in the modified example shown in Fig. 8. The electrically peelable adhesive sheet shown in Fig. 8 has an electrode contact portion 14, which is a portion to which an adherend is not attached, on at least one surface, and has a laminated structure in which a current-carrying substrate 12 and a second adhesive layer 13 are laminated on both surfaces of a first adhesive layer 11. In the modified example shown in FIG. 8, the double-sided electrically peelable pressure-sensitive adhesive sheet may be attached to the first adherend 15 on one side of the second adhesive layer 13, and attached to the second adherend 16 on the other side of the second adhesive layer 13. The double-sided electrically peelable pressure-sensitive adhesive sheet according to the embodiment of the present invention may have an extension portion 17 that extends beyond one of the current-carrying substrate 12 and the adherend 15 in the surface spreading direction and is exposed, as shown in FIG. 8, for example. In such a configuration, electrical connection between one terminal of the device to which a voltage is applied and the current-carrying substrate 12 is easily realized through the extension portion 17. The extension direction of the extension portion 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 is opposite in this embodiment. With such a configuration, it is easy to appropriately apply a voltage to the double-sided electrically peelable pressure-sensitive adhesive sheet by a voltage application device while avoiding, for example, a short circuit between the device terminals. 8, the non-exposed portion of the conductive layer 12a may be covered with the first pressure-sensitive adhesive layer 11. Moreover, 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 peelable adhesive sheet according to the embodiment of the present invention may be a double-sided electrically peelable adhesive sheet, as in the modified example shown in Fig. 9. The double-sided electrically peelable adhesive sheet shown in Fig. 9 has a laminated structure in which a conductive base material 12 and a second adhesive layer 13 are laminated on both sides of a first adhesive layer 11. In a 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 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 portion 17 that extends beyond one of the conductive substrates 12 and the adherend 15 in the surface spreading direction, as in the electrically peelable pressure-sensitive adhesive sheet shown in Fig. 8, and is exposed. The unexposed portion of the conductive layer 12a may be covered with a coating layer 12c as shown in Fig. 9. Moreover, 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 a 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 adhesion strength (against SUS304 plate, tensile speed 300 mm / min, peel temperature 23° C.) of the second adhesive layer 13 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. 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 an 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 to back the adhesive sheet 10. Next, a test piece (width 10 mm × length 100 mm) is cut out from the backed adhesive sheet 10. Next, the other separator is peeled off from the test piece, and the test piece is attached to a stainless steel plate (SUS304) as an adherend, and then a 2 kg roller is moved back and forth once to press the test piece and the adherend. Then, after leaving it to stand for 30 minutes, a peel tester (product name "Angle Peel Measuring Instrument YSP", manufactured by Asahi Seiko Co., Ltd.) is used to measure the 180° peel adhesion (tensile speed: 300 mm / min, peel temperature 23°C).

[0070] From the viewpoint of realizing good electrical peeling properties, the 180° peel adhesive strength after voltage application (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 less, more preferably 0.5 N / 10 mm or less, and even more preferably 0.2 N / 10 mm or less. The lower limit is not particularly limited, but is usually 0.01 N / 10 mm or more. The 180° peel adhesion after voltage application is the 180° peel adhesion (tensile speed: 300 mm / min, peel temperature 23°C) measured using a peel tester after pressing the test piece and adherend together as described above and leaving them to rest for 30 minutes, then applying a voltage of 10 V for 10 seconds and keeping the voltage applied.

[0071] Furthermore, it is preferable that the 180° peel adhesion of the first adhesive layer 11 after application of a voltage (hereinafter also referred to as "adhesion after voltage application") is sufficiently low compared to the 180° peel adhesion of the first adhesive layer 11 (hereinafter also referred to as "initial adhesion"), and the adhesion 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. Adhesive strength reduction rate (%) = {1-(adhesive strength after voltage application / initial adhesive strength)} x 100 (C)

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

[0073] Alternatively, the adhesive sheet 10 may be manufactured by a so-called transfer method. Specifically, first, the first adhesive layer 11 and the second adhesive layer 13 are formed on a separator (release liner), respectively. The first adhesive layer 11 is formed by applying the first composition for forming the first adhesive layer 11 to the release-treated surface of a given separator to form a coating film, and then drying the coating film. The second adhesive layer 13 is formed by applying the second composition for forming the second adhesive layer 13 to the release-treated surface of a given separator to form a coating film, and then drying the coating film. Next, the first adhesive layer 11 with the separator is bonded to the conductive layer 12a of the current-carrying substrate 12. Next, the second adhesive layer 13 with the separator is bonded to the surface of the current-carrying substrate 12 opposite to the first adhesive layer 11. For example, the adhesive sheet 10 can be manufactured 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 bonded to the surface of the conductive layer 12a of the conductive substrate 12. Next, the second adhesive layer 13 with a separator is bonded to the surface of the substrate layer 12b of the conductive substrate 12. For example, in this manner, the double-sided electrically peelable adhesive sheet shown in Fig. 8 can be produced. 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 adhesive layer 11 of the electrically peeling pressure-sensitive adhesive sheet shown in Fig. 7 is bonded to the surface of the coating layer 12c side of the conductive substrate 12 including the coating layer 12c. Next, the second adhesive layer 13 with a separator is bonded to the surface of the conductive substrate 12 on the substrate layer 12b side. For example, in this manner, the double-sided electrically peeling pressure-sensitive adhesive sheet shown in Fig. 9 can be produced.

[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 body of the present embodiment is a bonded body comprising: an electrically-peelable adhesive sheet comprising an electrically-peelable substrate having a conductive layer; a first adhesive layer made of an electrically-peelable adhesive formed on the conductive layer of the electrically-peelable substrate; and a second adhesive layer formed on the surface of the electrically-peelable substrate opposite the first adhesive layer; a first adherend attached to the first adhesive layer of the electrically-peelable adhesive sheet; and a second adherend attached to the second adhesive layer of the electrically-peelable adhesive sheet, wherein at least a portion of the first adherend to which the first adhesive layer is attached is electrically conductive, the electrically-peelable 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-peelable 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 the bonded body of this embodiment is separated, an electrode is brought into contact with the first adherend and the conductive layer, and a voltage is applied to the first adhesive layer to reduce the adhesive force of the first adhesive layer, thereby peeling off the first adherend from the first adhesive layer, thereby separating them. When the electrode is brought into contact with the conductive layer, the electrode penetrates the layer covering the conductive layer and contacts the conductive layer at the electrode contact surface in the electrode contact portion. That is, for example, in the example shown in FIG. 3, the electrode penetrates the first adhesive layer 11 and contacts the conductive layer 12a. Also, in the example shown in FIG. 6, the electrode penetrates the second adhesive layer 13 and the base layer 12b and contacts 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 which the electrode is brought into contact is conductive, and these portions are electrically connected.

[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. In addition, it 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. Within such a range, the joining body can be efficiently separated, which is preferable. For example, within such a range, it is possible to use an easily available power source such as a dry cell as the power source for the voltage application device. Furthermore, the time for applying the 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 separation operation of 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 body of the present embodiment is a bonded body comprising an electrically-peelable adhesive sheet comprising an electrically-peelable substrate having a conductive layer, a first adhesive layer made of an electrically-peelable adhesive formed on the conductive layer of the electrically-peelable substrate, and a second adhesive layer formed on the surface of the electrically-peelable substrate opposite the first adhesive layer, a first adherend attached to the first adhesive layer of the electrically-peelable adhesive sheet, and a second adherend attached to the second adhesive layer of the electrically-peelable adhesive sheet, wherein at least a portion of the first adherend to which the first adhesive layer is attached is conductive, and the first adherend is affixed to the entire surface of the electrically-peelable adhesive sheet facing the first adhesive layer, and the second adherend is affixed to the entire surface of the electrically-peelable adhesive sheet facing the second adhesive layer. That is, in the bonded body of the present 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 the bonded body of this embodiment is to be separated, an electrode is 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, thereby separating the bonded body. When the electrode is brought into contact with the conductive layer, the electrode penetrates the first adherend or the second adherend to bring the electrode 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 body of the present embodiment is a bonded body comprising an electrically peelable adhesive sheet comprising an electrically conductive base material having a conductive layer 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 base material opposite the first adhesive layer, a first adherend attached to one side of the second adhesive layer of the electrically peelable adhesive sheet, and a second adherend attached to the other side of the 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 the present 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 the bonded body of this embodiment is to be separated, an electrode is 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 force of the first pressure-sensitive adhesive layer, thereby peeling the first adherend from the first pressure-sensitive adhesive layer, thereby separating the bonded body. When the electrode is brought into contact with the conductive layer, the electrode penetrates the first adherend or the second adherend to bring the electrode into contact with 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. EXAMPLES

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

[0086] (Preparation of acrylic polymer solution) As monomer components, 87 parts by mass of n-butyl acrylate (BA), 10 parts by mass of 2-methoxyethyl acrylate (MEA), 3 parts by mass of acrylic acid (AA), and 150 parts by mass of ethyl acetate as a polymerization solvent 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, 0.2 parts by mass of 2,2'-azobisisobutyronitrile (AIBN) was added as a polymerization initiator, and the mixture was heated to 63°C and reacted for 6 hours. Then, ethyl acetate was added to obtain an acrylic polymer solution with a solid content concentration of 40% by mass.

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

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

[0089] (Ionic Liquid) AS-110: cation: 1-ethyl-3-methylimidazolium cation, anion: bis(fluorosulfonyl)imide anion, product name "Elexel AS-110", manufactured by Daiichi 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, product name "Irgamet 30", manufactured by BASF Japan Ltd.

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

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

[0092] [Example 2] An electrically peelable adhesive layer was prepared in the same manner as in Example 1, the polyethylene terephthalate separator (MRE38) from the obtained electrically peelable adhesive layer was peeled off, and the resin coat layer side of a film with a resin coat 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 coat layer (polyester-based resin layer), a conductive layer (metal layer (aluminum vapor deposition layer)), and a supporting substrate (PET) laminated in that order, was attached to the peeled surface so that one end of the laminate protruded from the electrically peelable adhesive layer by about 2 mm, as shown in Figure 7, to obtain an electrically peelable adhesive sheet. As an adherend, a stainless steel plate (SUS316, size: 30 mm×120 mm) was prepared as a conductive adherend. The polyethylene terephthalate separator (MRF38) was peeled off from the electrically peelable adhesive sheet obtained above, and the above-mentioned conductive adherend was attached to the surface of the peeled-off electrically peelable adhesive layer side, pressed back and forth once with a 2 kg roller, and left in an environment of 23°C for 30 minutes to obtain an assembly in which the unexposed parts of the conductive layer were covered with a resin coating layer.

[0093] [Example 3] A film with a metal layer (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 that 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 during the formation of the layer was set to -8°C. The polyethylene terephthalate separator (MRE38) from the electrically peelable adhesive layer prepared in the same manner as in Example 1 was peeled off, and the inorganic coating layer side of the above-mentioned substrate A was attached to the surface of the peeled-off 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 film with a metal layer (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 that 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 metal layer (Ni layer) with a thickness of 100 nm 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 bonded structure of Example 4 were obtained in the same manner as in Example 3, except that substrate A was changed to substrate B.

[0095] [Examples 5 and 6] Electrically peelable pressure-sensitive adhesive sheets and joined bodies of Examples 5 and 6 were obtained in the same manner as in Example 3, except that the thickness of the inorganic coating layer was changed to 100 nm and 200 nm, respectively.

[0096] [Comparative Example 1] An electrically peelable adhesive layer was prepared in the same manner as in Example 1, the polyethylene terephthalate separator (MRE38) from the obtained electrically peelable adhesive layer was peeled off, and a stainless steel plate (SUS316, size: 30 mm x 120 mm) was attached to the peeled surface as a conductive adherend to obtain a laminate. As the substrate, a film with a metal layer (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 that order. The polyethylene terephthalate separator (MRF38) was peeled off from the laminate obtained above, and the conductive layer side of the above-mentioned substrate was attached to the surface of the peeled-off electrically peelable pressure-sensitive adhesive layer side so that one end of the substrate protruded from the laminate by about 2 mm, as shown in Figure 2, and pressed back and forth once with a 2 kg roller and left in an environment of 23°C for 30 minutes, obtaining a bonded body 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 thermohygrostat 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 visually evaluated. The corrosion evaluation was performed by visually judging the presence or absence of corrosion.

[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 base material 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 electrical release adhesive comprises a polymer and an electrolyte, the electrolyte being an ionic liquid; an electrically peelable pressure-sensitive adhesive sheet, the conductive layer being not exposed across the entire surface of the first pressure-sensitive adhesive layer and the entire surface of the second pressure-sensitive adhesive layer;

2. A conductive substrate having a conductive layer; a first pressure-sensitive adhesive layer formed on the conductive layer of the conductive base material and made of an electrically peelable pressure-sensitive adhesive; an electrically peelable pressure-sensitive adhesive sheet including 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 adhesive layer of the electrically peelable adhesive sheet; a second adherend attached to the second adhesive layer of the electrically peelable adhesive sheet, The electrical release adhesive comprises a polymer and an electrolyte, the electrolyte being an ionic liquid; At least a portion of the first adherend to which the first pressure-sensitive adhesive layer is attached has electrical conductivity; A bonded body, in which the first adherend is affixed to the entire surface of the electrically peelable adhesive sheet facing the first adhesive layer, and the second adherend is affixed to the entire surface of the electrically peelable adhesive sheet facing the second adhesive layer.

3. 3. The method for separating a bonded body according to claim 2, comprising: 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.

Images