Electrically peelable adhesive sheet, bonded body, and method for separating bonded body

Abstract

The invention provides an electrically peelable adhesive sheet, a bonded body, and a method for separating the bonded body. The present invention relates to an electrically peelable pressure-sensitive adhesive sheet comprising: a conductive substrate having a conductive layer; a first adhesive layer formed from an electrically peelable adhesive, the first adhesive layer being formed on the conductive layer of the conductive substrate; and a second pressure-sensitive adhesive layer formed on a surface of the energizing base material on the opposite side from the first pressure-sensitive adhesive layer, the electrically peelable pressure-sensitive adhesive sheet having, on at least one surface thereof, an electrode contact portion that is a portion to which an adherend is not attached, the electrically peelable pressure-sensitive adhesive sheet having a first pressure-sensitive adhesive layer and a second pressure-sensitive adhesive layer formed on the surface of the energizing base material, at least a portion of a surface of the electrode contact portion to which the adherend is not attached has a portion in which the conductive layer is not exposed.

Description

[0001] This application is a divisional application of Chinese invention patent application No. 202080056001.1 (PCT application number is PCT / JP2020 / 030435) with an application date of August 7, 2020 and an invention name of “Electro-peelable adhesive sheet, bonded body and method for separating bonded body”. Technical Field

[0002] The present invention relates to an electro-peelable pressure-sensitive adhesive sheet, a joined body, and a method for separating the joined body. Background Art

[0003] In the process of manufacturing electronic components, there are increasing demands for reprocessing to improve the yield rate, recycling to disassemble and recover components after use, etc. In order to meet such demands, double-sided adhesive sheets having both a certain adhesive force and a certain releasability are sometimes used to join components in the process of manufacturing electronic components.

[0004] As a double-sided PSA sheet that achieves both adhesive strength and releasability, there is known a PSA sheet having an electrically releasable PSA layer formed from an electrically releasable PSA composition that is releasable by applying a voltage to the PSA layer (PATENT LITERATURE 1).

[0005] Prior art literature

[0006] Patent Literature

[0007] Patent Document 1: International Publication No. 2017 / 064925 Summary of the invention

[0008] Problems to be solved by the invention

[0009] like Figure 1 As shown, the electrically removable pressure-sensitive adhesive sheet 1 generally includes a portion (electrode contact portion 4) not used for bonding of adherends 2 and 3. Electrodes are brought into contact with the electrode contact portion 4 to apply a voltage to the electrically removable pressure-sensitive adhesive layer, thereby performing electrical peeling. Figure 2 Show Figure 1 4 is a side view obtained by enlarging the periphery of the electrode contact portion 4 in FIG. Generally, in the electrode contact portion 4, the conductive layer 6a is exposed in such a manner that the electrode can contact the conductive layer 6a in the substrate 6. By making the electrode contact the exposed conductive layer 6a and the adherend 2 attached to the side of the electrically removable adhesive layer 5, a voltage is applied to the electrically removable adhesive layer 5, so that the adhesive force of the electrically removable adhesive layer 5 is weakened, so that it can be easily peeled.

[0010] However, there is a problem that the exposed conductive layer 6 a in the electrode contact portion 4 may come into contact with the outside air and corrode, so that a voltage cannot be applied to the electro-peelable pressure-sensitive adhesive layer 5 and electro-peeling cannot be performed.

[0011] The present invention has been made based on the above circumstances, and an object of the present invention is to provide an electrically-peelable pressure-sensitive adhesive sheet in which corrosion of a conductive layer in an electrode contact portion is suppressed or prevented.

[0012] Another object of the present invention is to provide a bonded body having good electrical peelability and a method for separating such a bonded body.

[0013] Means for solving problems

[0014] The inventors of the present application have conducted intensive studies and have found that the above-mentioned problems can be achieved by using an electrically-peelable pressure-sensitive adhesive sheet or a joined body having a specific structure.

[0015] The first electrically-peelable adhesive sheet of the present invention for solving the above-mentioned problems comprises: a substrate for conducting electricity having a conductive layer; a first adhesive layer formed of an electrically-peelable adhesive, wherein the first adhesive layer is formed on the conductive layer of the substrate for conducting electricity; and a second adhesive layer, wherein the second adhesive layer is formed on the surface of the substrate for conducting electricity on the opposite side to the first adhesive layer, wherein the electrically-peelable adhesive sheet comprises an electrode contact portion as a portion to which an adherend is not attached on at least one side, and the surface of the electrode contact portion to which an adherend is not attached has a portion in which the conductive layer is not exposed in at least a part thereof.

[0016] In one embodiment of the first electrically-peelable pressure-sensitive adhesive sheet of the present invention, the conductive layer may not be exposed on the entire surface of the electrode contact portion that is not attached to the adherend.

[0017] In one embodiment of the first electrically-peelable pressure-sensitive adhesive sheet of the present invention, the surface of the electrode contact portion not to be bonded to the adherend 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.

[0018] In one embodiment of the first electrically-peelable pressure-sensitive adhesive sheet 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.

[0019] The second electrically-peelable adhesive sheet of the present invention comprises: a substrate for conducting electricity having a conductive layer; a first adhesive layer formed of an electrically-peelable adhesive, the first adhesive layer being formed on the conductive layer of the substrate for conducting electricity; and a second adhesive layer being formed on the surface of the substrate for conducting electricity on the opposite side to the first adhesive layer, wherein the electrically-peelable adhesive sheet has no conductive layer exposed in the entirety of the surface on the first adhesive layer side and the surface on the second adhesive layer side.

[0020] The first joint body of the present invention comprises an electrically-peelable adhesive sheet, 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 the electrically-peelable adhesive sheet comprises: a current-carrying substrate having a conductive layer; a first adhesive layer formed of an electrically-peelable adhesive, the first adhesive layer being formed on the conductive layer of the current-carrying substrate; and a second adhesive layer being formed on the surface of the current-carrying substrate opposite to the first adhesive layer, wherein in the joint body, at least a portion of the first adherend to which the first adhesive layer is attached is conductive, the electrically-peelable adhesive sheet comprises an electrode contact portion as a portion to which the adherend is not attached on at least one side, and the surface of the electrode contact portion to which the adherend is not attached has a portion where the conductive layer is not exposed in at least a portion thereof.

[0021] In one aspect of the first bonded body of the present invention, the conductive layer may not be exposed on the entire surface of the electrode contact portion to which the adherend is not attached.

[0022] In one aspect of the first bonded body of the present invention, in the electrode contact portion, the surface not bonded to the adherend is the surface on the first adhesive layer side, and the unexposed portion of the conductive layer is covered with the first adhesive layer.

[0023] In one embodiment of the first bonded body of the present invention, the current-carrying substrate may further include a coating layer, and an unexposed portion of the conductive layer may be covered with the coating layer.

[0024] The separation method of the first bonded body of the present invention is the above-mentioned separation method of the first bonded body, which includes: in the portion of the conductive layer not exposed on the surface of the electrode contact portion where the adherend is not attached, using an electrode to penetrate the layer covering the conductive layer so that the electrode contacts the conductive layer, and applying a voltage to the first adhesive layer.

[0025] The second bonded body of the present invention comprises an electrically-peelable adhesive sheet, 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 the electrically-peelable adhesive sheet comprises: a conductive substrate having a conductive layer; a first adhesive layer formed of an electrically-peelable adhesive, the first adhesive layer being formed on the conductive layer of the conductive substrate; and a second adhesive layer being formed on the surface of the conductive substrate opposite to the first adhesive layer, wherein in the bonded body, at least a portion of the first adherend to which the first adhesive layer is attached is conductive, the first adherend is attached to the entire surface of the electrically-peelable adhesive sheet on the first adhesive layer side, and the second adherend is attached to the entire surface on the second adhesive layer side.

[0026] The second bonded body separation method of the present invention is the above-mentioned second bonded body separation method, comprising: penetrating the first adherend or the second adherend with an electrode so that the electrode contacts the conductive layer, and applying a voltage to the first adhesive layer.

[0027] The third joint body of the present invention comprises an electrically-peelable adhesive sheet, a first adherend attached to one second adhesive layer of the electrically-peelable adhesive sheet, and a second adherend attached to another second adhesive layer of the electrically-peelable adhesive sheet, wherein the electrically-peelable adhesive sheet comprises a conductive substrate having a conductive layer on both sides of the first adhesive layer formed of an electrically-peelable adhesive, and a second adhesive layer formed on the surface of the conductive substrate on the opposite side to the first adhesive layer, wherein the electrically-peelable adhesive sheet comprises an electrode contact portion as a portion to which an adherend is not attached on at least one side, and the surface to which the adherend is not attached in the electrode contact portion has a portion where the conductive layer is not exposed in at least a part thereof.

[0028] For the third bonded body of the present invention, the method for separating the bonded body is the method for separating the second bonded body, comprising: using an electrode to penetrate the first adherend or the second adherend so that the electrode contacts at least one conductive layer, and applying a voltage to the first adhesive layer.

[0029] The present invention relates to the following items:

[0030] <1> , an electrically peelable adhesive sheet comprising:

[0031] A current-carrying substrate having a conductive layer;

[0032] a first adhesive layer formed of an adhesive for electrical peeling, the first adhesive layer being formed on the conductive layer of the current-carrying substrate; and

[0033] a second adhesive layer formed on a surface of the conducting substrate opposite to the first adhesive layer,

[0034] The electrically removable pressure-sensitive adhesive sheet has an electrode contact portion on at least one side thereof, which is a portion not to be attached to an adherend.

[0035] The surface of the electrode contact portion to which the adherend is not attached has a portion where the conductive layer is not exposed in at least a part thereof.

[0036] <2> ,like <1> In the electrically-peelable pressure-sensitive adhesive sheet, the conductive layer is not exposed on the entire surface of the electrode contact portion that is not attached to the adherend.

[0037] <3> ,like <1> or <2> In the electrically-peelable pressure-sensitive adhesive sheet, in the electrode contact portion, the surface not attached to the adherend is the surface on the first pressure-sensitive adhesive layer side, and the unexposed portion of the conductive layer is covered by the first pressure-sensitive adhesive layer.

[0038] <4> ,like <1> or <2> The electrically removable adhesive sheet, wherein the current-carrying substrate further comprises a coating layer,

[0039] The unexposed portion of the conductive layer is covered by the coating layer.

[0040] <5> , an electrically peelable adhesive sheet comprising:

[0041] A current-carrying substrate having a conductive layer;

[0042] a first adhesive layer formed of an adhesive for electrical peeling, the first adhesive layer being formed on the conductive layer of the current-carrying substrate; and

[0043] a second adhesive layer formed on a surface of the conducting substrate opposite to the first adhesive layer,

[0044] The conductive layer is not exposed in the entirety of the surface on the first adhesive layer side and the surface on the second adhesive layer side.

[0045] <6> , a bonded body comprising an electrically removable adhesive sheet, a first adherend attached to a first adhesive layer of the electrically removable adhesive sheet, and a second adherend attached to a second adhesive layer of the electrically removable adhesive sheet, wherein the electrically removable adhesive sheet comprises:

[0046] A current-carrying substrate having a conductive layer;

[0047] a first adhesive layer formed of an adhesive for electrical peeling, the first adhesive layer being formed on the conductive layer of the current-carrying substrate; and

[0048] a second adhesive layer formed on a surface of the conducting substrate opposite to the first adhesive layer,

[0049] In the conjugate,

[0050] At least a portion of the first adherend to which the first adhesive layer is attached has electrical conductivity.

[0051] The electrically removable pressure-sensitive adhesive sheet includes an electrode contact portion as a portion not to be attached to an adherend on at least one surface, and the surface of the electrode contact portion not to be attached to an adherend has a portion where the conductive layer is not exposed in at least a part thereof.

[0052] <7> ,like <6> In the above-mentioned bonded body, the conductive layer is not exposed on the entire surface of the electrode contact portion to which the adherend is not attached.

[0053] <8> ,like <6> or <7> In the bonded body, in the electrode contact portion, the surface not bonded to the adherend is the surface on the first adhesive layer side, and the unexposed portion of the conductive layer is covered by the first adhesive layer.

[0054] <9> ,like <6> or <7> The bonded body, wherein the current-carrying substrate further comprises a coating layer,

[0055] The unexposed portion of the conductive layer is covered by the coating layer.

[0056] <10> , <6> ~ <9> A method for separating a bonded body as described in any one of the items, comprising: in a portion of the electrode contact portion where the conductive layer is not exposed on the surface of the adherend not being attached, using an electrode to penetrate a layer covering the conductive layer so that the electrode contacts the conductive layer, and applying a voltage to the first adhesive layer.

[0057] <11> , a bonded body comprising an electrically removable adhesive sheet, a first adherend attached to a first adhesive layer of the electrically removable adhesive sheet, and a second adherend attached to a second adhesive layer of the electrically removable adhesive sheet, wherein the electrically removable adhesive sheet comprises:

[0058] A current-carrying substrate having a conductive layer;

[0059] a first adhesive layer formed of an adhesive for electrical peeling, the first adhesive layer being formed on the conductive layer of the current-carrying substrate; and

[0060] a second adhesive layer formed on a surface of the conducting substrate opposite to the first adhesive layer,

[0061] In the conjugate,

[0062] At least a portion of the first adherend to which the first adhesive layer is attached has electrical conductivity.

[0063] The first adherend is attached to the entire surface of the electrically removable pressure-sensitive adhesive sheet on the first pressure-sensitive adhesive layer side, and the second adherend is attached to the entire surface of the electrically removable pressure-sensitive adhesive sheet on the second pressure-sensitive adhesive layer side.

[0064] <12> , <11> The method for separating a bonded body described in , comprising: using an electrode to penetrate the first adherend or the second adherend so that the electrode contacts the conductive layer, and applying a voltage to the first adhesive layer.

[0065] <13> , a bonded body comprising an electrically peelable adhesive sheet, a first adherend attached to one second adhesive layer of the electrically peelable adhesive sheet, and a second adherend attached to another second adhesive layer of the electrically peelable adhesive sheet,

[0066] The electrically peelable adhesive sheet comprises a conductive substrate having a conductive layer on both sides of a first adhesive layer formed of an electrically peelable adhesive, and a second adhesive layer formed on a surface of the conductive substrate opposite to the first adhesive layer.

[0067] In the conjugate,

[0068] The electrically removable pressure-sensitive adhesive sheet includes an electrode contact portion as a portion not to be attached to an adherend on at least one surface, and the surface of the electrode contact portion not to be attached to an adherend has a portion where the conductive layer is not exposed in at least a part thereof.

[0069] <14> , <13> The method for separating a bonded body described in , comprising: using an electrode to penetrate the first adherend or the second adherend so that the electrode contacts at least one of the conductive layers, and applying a voltage to the first adhesive layer.

[0070] Effects of the Invention

[0071] In the electro-peelable pressure-sensitive adhesive sheet of the present invention, corrosion of the conductive layer in the electrode contact portion is suppressed or prevented. In addition, the bonded body of the present invention has good electro-peelability. BRIEF DESCRIPTION OF THE DRAWINGS

[0072] [ Figure 1 ] Figure 1 This is a schematic three-dimensional view of a bonded structure formed by bonding adherends using an electrically removable pressure-sensitive adhesive sheet.

[0073] [ Figure 2 ] Figure 2 This is a schematic side view showing an enlarged view of the periphery of an electrode contact portion in a conventional electrically removable pressure-sensitive adhesive sheet.

[0074] [ Figure 3 ] Figure 3 This is a schematic side view showing an enlarged view of the periphery of the electrode contact portion in a joined body formed by bonding adherends with the electrically-peelable pressure-sensitive adhesive sheet according to one embodiment of the present invention.

[0075] [ Figure 4 ] Figure 4 This is a schematic side view showing an enlarged view of the periphery of an electrode contact portion in a joined body formed by bonding adherends with an electrically removable pressure-sensitive adhesive sheet according to a modified example of one embodiment of the present invention.

[0076] [ Figure 5] Figure 5 This is a schematic perspective view of a joined body formed by bonding adherends using an electrically removable pressure-sensitive adhesive sheet according to a modified example of one embodiment of the present invention.

[0077] [ Figure 6 ] Figure 6 This is a schematic side view showing an enlarged view of the periphery of an electrode contact portion in a joined body formed by bonding adherends with an electrically removable pressure-sensitive adhesive sheet according to a modified example of one embodiment of the present invention.

[0078] [ Figure 7 ] Figure 7 This is a schematic side view showing an enlarged view of the periphery of an electrode contact portion in a joined body formed by bonding adherends with an electrically removable pressure-sensitive adhesive sheet according to a modified example of one embodiment of the present invention.

[0079] [ Figure 8 ] Figure 8 This is a schematic side view showing an enlarged view of the periphery of an electrode contact portion in a joined body formed by bonding adherends with an electrically removable pressure-sensitive adhesive sheet according to a modified example of one embodiment of the present invention.

[0080] [ Fig. 9 ] Fig. 9 This is a schematic side view showing an enlarged view of the periphery of an electrode contact portion in a joined body formed by bonding adherends with an electrically removable pressure-sensitive adhesive sheet according to a modified example of one embodiment of the present invention. DETAILED DESCRIPTION

[0081] Hereinafter, the mode for implementing the present invention will be described in detail. It should be noted that the present invention is not limited to the embodiment described below.

[0082] [Adhesive sheet]

[0083] Figure 3 The figure shows an enlarged side view of the electrode contact portion 14 and its surroundings in a joint body formed by bonding adherends (first adherend 15 and second adherend 16) using the electrically removable adhesive sheet 10 (hereinafter also simply referred to as "adhesive sheet 10") of the present embodiment.

[0084] The adhesive sheet 10 of the present embodiment comprises: a conductive substrate 12 having a conductive layer 12a; a first adhesive layer 11 formed of an electrical peeling adhesive, which is formed on the conductive layer 12a of the conductive substrate 12; and a second adhesive layer 13, which is formed on the surface of the conductive substrate 12 opposite to the first adhesive layer 11. In addition, the adhesive sheet 10 of the present embodiment comprises an electrode contact portion 14 as a portion not attached to an adherend on at least one side, and the surface of the electrode contact portion 14 not attached to an adherend (on the side of the electrode contact portion 14) is provided with a conductive layer 12a having a conductive layer 12a. Figure 3In the example shown, the surface on the first adhesive layer 11 side has a portion where the conductive layer 12a is not exposed in at least a part thereof.

[0085] (First adhesive layer)

[0086] The first adhesive layer 11 is an adhesive layer formed of an adhesive for electro-peeling (electro-peelable adhesive layer), and contains a polymer as an adhesive and an electrolyte.

[0087] Examples of the polymer contained in the first adhesive layer 11 include acrylic polymers, rubber polymers, vinyl alkyl ether polymers, silicone polymers, polyester polymers, polyamide polymers, urethane polymers, fluorine polymers, and epoxy polymers. The first adhesive layer 11 may contain only one polymer or two or more polymers.

[0088] From the viewpoint of reducing costs and achieving high productivity, it is preferred to contain an acrylic polymer. The so-called acrylic polymer is a polymer containing monomer units derived from alkyl acrylate and / or alkyl methacrylate as the main monomer units in terms of mass ratio. Hereinafter, "(meth)acrylic-" is used to represent "acrylic-" and / or "methacrylic-".

[0089] When the first adhesive layer 11 contains an acrylic polymer, the acrylic polymer preferably contains a monomer unit derived from an alkyl (meth)acrylate having an alkyl group with 1 to 14 carbon atoms. Examples of the alkyl (meth)acrylate 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 alkyl (meth)acrylate may be used, or two or more alkyl (meth)acrylates may be used.

[0090] From the viewpoint of achieving high adhesive force to the first adhesive layer 11, the ratio of the monomer unit derived from the (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. That is, from the viewpoint of achieving high adhesive force to the first adhesive layer 11, the ratio of the (meth)acrylic acid alkyl ester having an alkyl group with 1 to 14 carbon atoms in the total amount of the raw material monomers used to form 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.

[0091] When the first adhesive layer 11 contains an acrylic polymer, the acrylic polymer preferably contains a monomer unit derived from a monomer containing a polar group from the viewpoint of achieving high adhesive force for the first adhesive layer 11. Examples of the monomer containing a polar group include a carboxyl group-containing monomer, a methoxy group-containing monomer, a hydroxyl group-containing monomer, and a vinyl monomer.

[0092] As the monomer containing a carboxyl group, for example, acrylic acid, methacrylic acid, itaconic acid, maleic acid, fumaric acid, crotonic acid, isocrotonic acid, carboxyethyl (meth)acrylate, and carboxypentyl (meth)acrylate can be cited. Among these, acrylic acid and methacrylic acid are preferred. In addition, one monomer containing a carboxyl group can be used, and two or more monomers containing a carboxyl group can also be used.

[0093] Examples of the methoxy group-containing monomer include 2-methoxyethyl acrylate.

[0094] As the monomer containing hydroxyl group, for example, 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, methyl acrylate (4-hydroxymethylcyclohexyl), N-hydroxymethyl (meth)acrylamide, vinyl alcohol, allyl alcohol, 2-hydroxyethyl vinyl ether, 4-hydroxybutyl vinyl ether, and diethylene glycol monovinyl ether can be mentioned. Among these, 2-hydroxyethyl (meth)acrylate is preferred. In addition, a monomer containing hydroxyl group can be used, and two or more monomers containing hydroxyl group can also be used.

[0095] As the monomer containing a vinyl group, for example, vinyl acetate, vinyl propionate, and vinyl laurate can be mentioned. Among these, vinyl acetate is preferred. In addition, one monomer containing a vinyl group can be used, or two or more monomers containing a vinyl group can be used.

[0096] From the viewpoint of ensuring cohesive force in the first adhesive layer 11 and preventing residual adhesive from being generated on the surface of the adherend after the first adhesive layer 11 is peeled off, the proportion of the monomer unit derived from the monomer containing a polar group in the above-mentioned acrylic polymer is preferably 0.1% by mass or more. That is, from the viewpoint of ensuring cohesive force and preventing residual adhesive, the proportion of the monomer containing a polar group in the total amount of the raw monomers used to form the above-mentioned acrylic polymer is preferably 0.1% by mass or more. In addition, from the viewpoint of appropriately presenting the characteristics generated by the monomer unit derived from the above-mentioned (meth) acrylic acid alkyl ester having an alkyl group with 1 to 14 carbon atoms in the acrylic polymer, the proportion of the monomer unit derived from the monomer containing a polar group in the above-mentioned acrylic polymer is preferably 30% by mass or less. That is, from the viewpoint of presenting this characteristic, the proportion of the monomer containing a polar group in the total amount of the raw monomers used to form the above-mentioned acrylic polymer is preferably 30% by mass or less.

[0097] The method for obtaining the acrylic polymer by polymerizing the above-mentioned monomers is not particularly limited, and a known method can be used. Examples of the polymerization method include solution polymerization, emulsion polymerization, bulk polymerization, and suspension polymerization.

[0098] From the viewpoint of achieving sufficient adhesive force in the first adhesive layer 11 , the content of the polymer in the first adhesive layer 11 is preferably 70 mass % or more, more preferably 80 mass % or more, more preferably 85 mass % or more, and more preferably 90 mass % or more.

[0099] The electrolyte contained in the first 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, alkaline earth metal salts, etc. From the viewpoint of achieving good electrical peelability in the first adhesive layer 11, an ionic liquid is preferably used as the electrolyte contained in the first adhesive layer 11. An ionic liquid is a salt that is liquid at room temperature (about 25° C.) and contains anions and cations.

[0100] When the first adhesive layer 11 contains an ionic liquid, the anion of the ionic liquid preferably contains an anion selected from the group consisting of (FSO 2 ) 2 N - ,(CF 3 SO 2 ) 2 N - ,(CF 3 CF 2 SO 2 ) 2 N - ,(CF 3 SO 2 )3 C - Br - 、AlCl 4 - 、Al 2 Cl 7 - 、NO 3 - , BF 4 - PF 6 - , CH 3 COO - CF 3 COO - CF 3 CF 2 CF 2 COO - CF 3 SO 3 - CF 3 (CF 2 ) 3 SO 3 - , AsF 6 - , SbF 6 - and F(HF) n - At least one of the group consisting of. Among them, as anion, (FSO 2 ) 2 N - [bis(fluorosulfonyl)imide anion], and (CF 3 SO 2 ) 2 N - The [bis(trifluoromethanesulfonyl)imide anion] is suitable and preferred from the viewpoint of chemical stability and achieving electrical peelability of the first adhesive layer 11 .

[0101] When the first adhesive layer 11 contains an ionic liquid, the cation of the ionic liquid preferably contains at least one selected from the group consisting of imidazolium cations, pyridinium cations, pyrrolidinium cations, and ammonium cations.

[0102] Examples of the imidazolium cation 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, and the like. The invention also includes a 1-tridecyl-3-methylimidazolium cation, a 1-tetradecyl-3-methylimidazolium cation, a 1-pentadecyl-3-methylimidazolium cation, a 1-hexadecyl-3-methylimidazolium cation, a 1-heptadecyl-3-methylimidazolium cation, a 1-octadecyl-3-methylimidazolium cation, a 1-undecyl-3-methylimidazolium cation, a 1-benzyl-3-methylimidazolium cation, a 1-butyl-2,3-dimethylimidazolium cation, and a 1,3-bis(dodecyl)imidazolium cation.

[0103] Examples of the pyridinium cation include 1-butylpyridinium cation, 1-hexylpyridinium cation, 1-butyl-3-methylpyridinium cation, 1-butyl-4-methylpyridinium cation, and 1-octyl-4-methylpyridinium cation.

[0104] Examples of the pyrrolidinium cation include a 1-ethyl-1-methylpyrrolidinium cation and a 1-butyl-1-methylpyrrolidinium cation.

[0105] Examples of the ammonium cation include a tetraethylammonium cation, a tetrabutylammonium cation, a methyltrioctylammonium cation, a tetradecyltrihexylammonium cation, a glycidyltrimethylammonium cation, and a trimethylaminoethylacrylate cation.

[0106] As the ionic liquid in the first adhesive layer 11, from the viewpoint of realizing high electrical peeling properties in the first adhesive layer 11 by utilizing the high diffusivity of cations, it is particularly preferable to include the above-mentioned (FSO 2 ) 2An ionic liquid of N-[bis(fluorosulfonyl)imide anion] and a cation having a molecular weight of 160 or less. 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 trimethylaminoethylacrylate cation.

[0107] Examples of commercially available ionic liquids contained in the first adhesive layer 11 include “ELEXCEL AS-110”, “ELEXCEL MP-442”, “ELEXCEL IL-210”, “ELEXCEL MP-471”, “ELEXCEL MP-456”, and “ELEXCEL AS-804” manufactured by Daiichi Kogyo Seiyaku Co., Ltd.

[0108] Examples of the alkali metal salt include LiCl, Li 2 SO 4 , LiBF 4 、LiPF 6 、LiClO 4 、LiAsF 6 、LiCF 3 SO 3 、LiN(SO 2 CF 3 ) 2 、LiN(SO 2 C 2 F 5 ) 2 、LiC(SO 2 CF 3 ) 3 , NaCl, Na 2 SO 4 , NaBF 4 、NaPF 6 、NaClO 4 、NaAsF 6 、NaCF 3 SO 3 、NaN(SO 2 CF 3 ) 2 、NaN(SO 2 C 2 F5 ) 2 、NaC(SO 2 CF 3 ) 3 , KCl, K 2 SO 4 KBF 4 、KPF 6 , KClO 4 , KASF 6 、KCF 3 SO 3 、KN(SO 2 CF 3 ) 2 、KN(SO 2 C 2 F 5 ) 2 and KC(SO 2 CF 3 ) 3 .

[0109] The content of the ionic liquid in the first 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 adhesive layer 11 in order to impart electrical peeling properties to the first adhesive layer 11. From the viewpoint of achieving better electrical peeling properties, it is preferably 0.5 parts by mass or more, more preferably 0.6 parts by mass or more, further 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 achieving good adhesion and electrical peeling properties with good balance for the first adhesive layer 11, the content of the ionic liquid in the first adhesive layer 11 is preferably 30 parts by mass or less relative to 100 parts by mass of the polymer in the first adhesive layer 11, more preferably 20 parts by mass or less, further preferably 15 parts by mass or less, particularly preferably 10 parts by mass or less, and most preferably 5 parts by mass or less.

[0110] The 1st adhesive layer 11 can contain other components in the scope that does not damage the effect of the present invention.As such composition, can enumerate for example tackifier, silane coupling agent, coloring agent, pigment, dye, surface lubricant, leveling agent, softener, antioxidant, anti-aging agent, light stabilizer, polymerization inhibitor, inorganic or organic filler, metal powder, particle-shaped thing, corrosion inhibitor and foil-shaped thing, can use the various additives in resin combination.The content of these components can be determined in the scope that does not damage the effect of the present invention according to use purpose.For example, for example below 10 mass parts with respect to polymer 100 mass parts.

[0111] The thickness of the first adhesive layer 11 is not particularly limited, but is preferably 1 μm or more, more preferably 3 μm or more, further preferably 5 μm or more, and particularly preferably 8 μm or more from the viewpoint of achieving good adhesion in the first adhesive layer 11. In addition, from the viewpoint of reducing the applied voltage when peeling the adherend, it is preferably 1000 μm or less, more preferably 500 μm or less, further preferably 100 μm or less, and particularly preferably 30 μm or less.

[0112] (Second adhesive layer)

[0113] The second adhesive layer 113 contains a polymer for imparting adhesiveness to the second adhesive layer 113. The components and contents contained in the second adhesive layer 113 are the same as those described above for the first adhesive layer 111, except for the electrolyte.

[0114] The thickness of the second adhesive layer 113 is not particularly limited, but is preferably 1 μm or more, more preferably 3 μm or more, further preferably 5 μm or more, and particularly preferably 8 μm or more from the viewpoint of achieving good adhesion in the second adhesive layer 113. In addition, it is preferably 1000 μm or less, more preferably 500 μm or less, and further preferably 100 μm or less.

[0115] (Electrical base material)

[0116] The conductive substrate is not particularly limited as long as it has a conductive layer. Figure 3 The laminated structure having the conductive layer 12a and the base layer 12b as in the example shown in the figure may also be as follows Figure 4 The conductive substrate may also include a coating layer, such as the one shown in the modified example. Figure 7 As in the illustrated modification, it has a laminated structure of a coating layer 12c, a conductive layer 12a, and a base layer 12b. Figure 7 In the illustrated modification, the portion where the conductive layer 12a is not exposed may be covered with the coating layer 12c. Alternatively, the current-carrying substrate may have a laminated structure having a coating layer and a conductive layer.

[0117] The thickness of the current-carrying substrate is not particularly limited. In any configuration, it is preferably, for example, 10 μm or more, more preferably 12 μm or more, further preferably 25 μm or more. In addition, it is preferably, for example, 1000 μm or less, more preferably 500 μm or less, further preferably 300 μm or less, and particularly preferably 100 μm or less.

[0118] Figure 3In the illustrated example, in the conductive substrate 12 of the laminated structure, the substrate layer 12b is a portion that functions as a support, and is, for example, a plastic substrate, a fiber substrate, or a paper substrate, or a laminate thereof. The substrate layer 12b may be a single layer or a multilayer. In addition, the substrate layer 12b may be subjected to various treatments such as back surface treatment, antistatic treatment, and primer treatment as required.

[0119] The thickness of the substrate layer 12b is not particularly limited, but is preferably 10 μm or more, more preferably 12 μm or more, further preferably 25 μm or more, and is preferably 1000 μm or less, more preferably 500 μm or less, further preferably 300 μm or less, and particularly preferably 100 μm or less.

[0120] The conductive layer 12a is a conductive layer, and is formed of a conductive material such as metal (eg, aluminum, copper, iron, tin, gold, or alloys thereof), a conductive polymer, a conductive metal oxide (eg, ITO), or carbon.

[0121] The conductive layer 12 a can be formed by, for example, a plating method, a chemical vapor deposition method, or a sputtering method.

[0122] 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, further 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, further preferably 300 μm or less, particularly preferably 50 μm or less, and most preferably 10 μm or less.

[0123] The coating layer 12 c is a layer mainly composed of a resin or an inorganic substance, and can be formed using a resin composition mainly composed of a resin component or a composition composed of an inorganic substance.

[0124] When the coating layer 12c has a resin as a main component, examples of the resin component constituting the coating layer 12c (resin coating layer) include epoxy resins, polyester resins, acrylic resins, or urethane resins, and these may be used alone or in a mixture.

[0125] The resin composition forming the coating layer 12 c (resin coating layer) having a resin as a main component preferably contains the above-mentioned resin component (polymer) as a main component.

[0126] The content of the polymer in the resin composition of the present 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), the upper limit is more preferably 99.5% by mass, further preferably 99% by mass, and the lower limit is more preferably 60% by mass, further preferably 70% by mass.

[0127] The resin composition may further contain a curing agent. As the curing agent, a commonly used curing agent such as an isocyanate curing agent, an epoxy curing agent, or a melamine curing agent can be used.

[0128] The resin composition of the present embodiment may also contain various additives such as filler, plasticizer, anti-aging agent, antioxidant, pigment (dye), flame retardant, solvent, surfactant (leveling agent), rust inhibitor, anticorrosive agent and antistatic agent. For the total content of these components, as long as the effect of the present invention is achieved, there is no particular restriction, but preferably relative to 100 parts by mass of resin, it is more than 0.01 parts by mass and less than 20 parts by mass, more preferably less than 10 parts by mass, and more preferably less than 5 parts by mass.

[0129] Examples of the filler include silicon dioxide, iron oxide, zinc oxide, aluminum oxide, titanium oxide, barium oxide, magnesium oxide, calcium carbonate, magnesium carbonate, zinc carbonate, pyrophyllite clay, kaolin, and calcined clay.

[0130] As the plasticizer, known and commonly used plasticizers used in conventional resin compositions 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.

[0131] Examples of the antioxidant include hindered phenol-based compounds and aliphatic and aromatic hindered amine-based compounds.

[0132] Examples of the antioxidant include butylhydroxytoluene (BHT) and butylhydroxyanisole (BHA).

[0133] Examples of the pigment include inorganic pigments such as titanium dioxide, zinc oxide, ultramarine blue, red iron oxide, lithopone, lead, cadmium, iron, cobalt, aluminum, hydrochloride, and sulfate; organic pigments such as azo pigments; and copper phthalocyanine pigments.

[0134] Examples of the rust preventive include zinc phosphate, tannic acid derivatives, phosphoric acid esters, basic sulfonates, and various rust preventive pigments.

[0135] Examples of the anticorrosive agent include carbodiimide compounds, adsorption-type corrosion inhibitors, and chelate-forming metal passivators. For example, the anticorrosive agents described in Japanese Patent Application Laid-Open No. 2019-059908 can be used.

[0136] Examples of the antistatic agent generally include quaternary ammonium salts, or hydrophilic compounds such as polyglycolic acid and ethylene oxide derivatives.

[0137] 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 resin composition, an active energy ray-curable resin composition, etc. Here, the so-called water-based resin composition refers to a resin composition in the form of a coating-forming component contained in a solvent (aqueous solvent) with water as the main component, and its concept includes a water-dispersible resin composition in the form of a coating-forming component dispersed in water, and a water-soluble resin composition in the form of a coating-forming component dissolved in water.

[0138] The coating 12c (resin coating) with resin as the main component can be formed by applying the resin composition using known techniques such as gravure coating, reverse roll coating, roller coating, dip coating, comma coating, etc., drying it, and then curing it by irradiating it with ultraviolet rays, electron beams, etc. as needed.

[0139] From the viewpoint of electrical stripping properties, the thickness of the coating layer 12c (resin coating layer) mainly composed 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 μm, and particularly preferably 500 nm, and the lower limit is more preferably 15 nm, further preferably 20 nm, and particularly preferably 30 nm.

[0140] When the coating layer 12 c contains an inorganic substance as a main component, examples of the inorganic substance constituting the coating layer 12 c (inorganic coating layer) include metals, metal alloys, metal oxides, and metal nitrides.

[0141] Examples of the metal include silicon, aluminum, nickel, chromium, tin, gold, silver, platinum, zinc, titanium, tungsten, zirconium, and palladium.

[0142] As the inorganic substance, Al is preferred. 2 O 3 , Ni, NiCr, or SiNx, SiOx, etc. as inorganic nitrides or inorganic oxides with non-stoichiometric compositions.

[0143] The coating layer 12 c (inorganic coating layer) mainly composed of an inorganic substance can be formed by a sputtering method, a vapor deposition method, or the like.

[0144] From the viewpoint of electrical stripping, the thickness of the coating layer 12c (inorganic coating layer) mainly composed of inorganic substances 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.

[0145] Figure 4 In the illustrated modification, the current-carrying base material 22 having a single-layer structure is formed only of the conductive layer 22 a , and has both the function of a support and the function of a conductor.

[0146] (Electrode contact part)

[0147] The pressure-sensitive adhesive sheet 10 of the present embodiment includes an electrode contact portion 14 on at least one surface thereof, which is a portion to which an adherend is not attached.

[0148] The shape of the electrode contact portion is not particularly limited. For example, it can be Figure 1 The shape of the tab extending outwards as in the prior art example shown in FIG. Figure 5 When an adherend having an opening is attached as shown, the adherend is not attached to the opening portion, and the portion where the adherend is not attached becomes the electrode contact portion 14 .

[0149] 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 portion of the surface of the electrode contact portion 14 to which the adherend is not attached (hereinafter also referred to as “electrode contact surface”).

[0150] The unexposed portion of the conductive layer 12a may be Figure 3 As shown, it is covered by the first adhesive layer 11.

[0151] In addition, the unexposed portion of the conductive layer 12a may be Figure 7 As shown, it is covered by coating 12c.

[0152] The conductive layer 12a is not easily corroded in the portion where the conductive layer 12a is not exposed, so the possibility of failure of electrical stripping due to corrosion of the conductive layer 12a is suppressed in the adhesive sheet 10 of this embodiment. It should be noted that the method of performing electrical stripping by bringing an electrode into contact with the unexposed conductive layer 12a will be described later.

[0153] In the adhesive sheet 10 of the present embodiment, the conductive layer 12a only needs to be not exposed in at least a portion of the surface of the electrode contact portion 14 where the adherend is not attached. However, in order to further suppress corrosion of the conductive layer 12a, it is preferred 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, further preferably 80% or more, and most preferably 100%. That is, it is preferred that the conductive layer 12a is not exposed in the entire electrode contact surface of the electrode contact portion 14.

[0154] In the adhesive sheet 10 of the present embodiment, it is particularly preferred that the conductive layer 12 a is not exposed in the entirety of the surface on the first adhesive layer 11 side and the surface on the second adhesive layer 13 side from the viewpoint of suppressing corrosion.

[0155] Figure 3 In the adhesive sheet 10 of the example shown, the surface of the electrode contact portion 14 on the first adhesive layer 11 side becomes the electrode contact surface, that is, the surface on the first adhesive layer 11 side is not attached to the adherend, but it may also be as shown in FIG. Figure 6 As shown, the surface on the second adhesive layer 13 side becomes the electrode contact surface. That is, in the electrode contact portion 14, the surface on the second adhesive layer 13 side may not have an adherend attached thereto.

[0156] It should be noted that in the electrode contact portion, it is also possible that no adherend is attached to both the surface on the first adhesive layer 11 side and the surface on the second adhesive layer 13 side. However, in this case, the electrode contact portion 14 becomes unstable and is not easy to contact the electrode, and it is not easy to be electrically peeled. Therefore, it is preferred that Figure 3 The example shown, Figure 6 As in the illustrated example, in the electrode contact portion 14 , an adherend is attached to either the surface on the first adhesive layer 11 side or the surface on the second adhesive layer 13 side.

[0157] In the pressure-sensitive adhesive sheet 10 of the present embodiment, it is particularly preferred that the surface of the electrode contact portion 14 on the first pressure-sensitive adhesive layer side has no adherend, that is, the surface of the electrode contact portion 14 on the first pressure-sensitive adhesive layer side is the electrode contact surface.

[0158] When the electrode is brought into contact with the conductive layer in the electrode contact portion, for example, the electrode is made to penetrate the layer covering the conductive layer 12a to bring the electrode into contact with the conductive layer 12a. Details will be described later.

[0159] At this time, if Figure 3When the surface on the first adhesive layer 11 side is the electrode contact surface as shown, the electrode can be brought into contact with the conductive layer 12a simply by penetrating the first adhesive layer 11 covering the conductive layer 12a, so that electrical peeling can be performed relatively easily.

[0160] On the other hand, Figure 6 When the surface on the second adhesive layer 13 side is the electrode contact surface as shown, in order to make the electrode contact the conductive layer 12a, it is necessary to penetrate at least the base layer 12b. The base layer 12b is usually thick and strong, so it is not easy to penetrate it with an electrode compared to the case where the electrode penetrates the first adhesive layer 11. In addition, when the electrode that penetrates the base layer 12b also penetrates the conductive layer 12a and the first adhesive layer 11 and contacts the first adherend 15, it becomes impossible to apply a voltage to the first adhesive layer, so precise control is required when the electrode penetrates the base layer 12b.

[0161] like Figure 4 The same is true when the conductive substrate 22 is a single-layer structure formed by the conductive layer 22a as shown in the modified example. 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 making the electrode contact the conductive layer 22a, but precise control is also required.

[0162] It should be noted that 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 the present embodiment. The separator is an element for protecting the first adhesive layer 11 and the second adhesive layer 13 of the adhesive sheet 10 in a manner that they are not exposed, and is peeled off from the adhesive sheet 10 when the adhesive sheet 10 is attached to the adherend. The adhesive sheet 10 may be sandwiched between two separators, or the adhesive sheet 10 and the separator may be wound into a roll together in a manner that the adhesive sheet 10 and the separator are alternately arranged. As a separator, for example, a substrate having a release treatment layer, a low-adhesion substrate formed by a fluoropolymer, and a low-adhesion substrate formed by a non-polar polymer can be cited. The surface of the separator may be subjected to a demolding treatment, an antifouling treatment, or an antistatic treatment. The thickness of the separator is, for example, 5 to 200 μm.

[0163] The electrically removable pressure-sensitive adhesive sheet according to the embodiment of the present invention can be Figure 8 A double-sided electrically removable pressure-sensitive adhesive sheet was prepared as in the modified example shown. Figure 8 The electrically removable pressure-sensitive adhesive sheet shown has an electrode contact portion 14 as a portion not attached to an adherend on at least one surface, and has a laminated structure in which a conductive substrate 12 and a second pressure-sensitive adhesive layer 13 are laminated on both surfaces of a first pressure-sensitive adhesive layer 11 .

[0164] Figure 8In the modified example shown, the double-sided electrically removable adhesive sheet can be attached to the first adherend 15 with one surface on the second adhesive layer 13 side, and attached to the second adherend 16 with the other surface on the second adhesive layer 13 side. Figure 8 As shown, there is an extended protrusion 17 that is further extended and exposed than the conducting substrate 12 and the adherend 15 on one side in the direction of its surface extension. In such a structure, it is easy to achieve electrical connection between one terminal of the device for applying voltage and the conducting substrate 12 via the extended protrusion 17. Moreover, the extending direction of the extended protrusion 17 extending from the conducting substrate 12 and the adherend 15 on one side is different from the extending direction of the electrode contact part 14, and is in the opposite direction in this embodiment. If such a structure is used, it is easy to appropriately implement voltage application to the double-sided electrically removable adhesive sheet using a voltage applying device while avoiding, for example, short circuits between the device terminals.

[0165] The unexposed portion of the conductive layer 12a may be Figure 8 As shown in the figure, the conductive layer 12a is covered by the first adhesive layer 11. In addition, it is preferred that the conductive layer 12a in the extended protrusion 17 is not exposed and can be covered by the first adhesive layer 11.

[0166] In addition, the electrically removable adhesive sheet according to the embodiment of the present invention may also be Fig. 9 A double-sided electrically removable pressure-sensitive adhesive sheet was prepared as in the modified example shown. Fig. 9 The double-sided electrically removable pressure-sensitive adhesive sheet shown has a laminated structure in which a conductive substrate 12 and a second pressure-sensitive adhesive layer 13 are laminated on both surfaces of a first pressure-sensitive adhesive layer 11 .

[0167] Fig. 9 In the illustrated modification, the double-sided electrically removable pressure-sensitive adhesive sheet can be attached to the first adherend 15 at one surface on the second pressure-sensitive adhesive layer 13 side and attached to the second adherend 16 at the other surface on the second pressure-sensitive adhesive layer 13 side.

[0168] The conductive substrate may be Fig. 9 As in the modified example shown in the figure, the conductive substrate has a laminated structure of a coating layer 12c, a conductive layer 12a, and a base layer 12b. Alternatively, the conductive base may have a laminated structure of a coating layer and a conductive layer. Fig. 9 The electrically removable adhesive sheet in the modified example shown can be used with Figure 8 The electrically removable pressure-sensitive adhesive sheet shown in the figure similarly has an extended protrusion 17 which is further extended and exposed than the conducting substrate 12 and the adherend 15 on one side in the direction of surface expansion.

[0169] The unexposed portion of the conductive layer 12a may be Fig. 9As shown in the figure, the conductive layer 12a is covered by the coating layer 12c. In addition, it is preferred that the conductive layer 12a in the extended protrusion 17 is not exposed and can be covered by the coating layer 12c.

[0170] (Adhesion strength of adhesive sheet)

[0171] From the viewpoint of achieving good adhesive strength, the 180° peeling adhesive strength (relative to SUS304 plate, tensile speed 300 mm / min, peeling 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 further preferably 3.0 N / 10 mm or more. The upper limit is not particularly limited, but is usually 20 N / 10 mm or less.

[0172] In addition, from the same viewpoint, the 180° peeling adhesive force (relative to SUS304 plate, tensile speed 300 mm / min, peeling 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 further preferably 3.0 N / 10 mm or more. The upper limit is not particularly limited, but is usually 20 N / 10 mm or less.

[0173] The 180° peel strength of the pressure-sensitive adhesive sheet 10 can be measured, for example, in accordance with JIS Z 0237 as follows.

[0174] First, for the adhesive sheet 10 with a separator on both sides, after peeling off the separator on one side, a polyethylene terephthalate (PET) film with a thickness of 50 μm is attached to the exposed adhesive surface to mount the adhesive sheet 10. Next, a test piece (width 10 mm × length 100 mm) is cut out from the mounted adhesive sheet 10. Next, the separator on the other side is peeled off from the test piece, and the test piece is attached to a stainless steel plate (SUS304) as an adherend, and a 2 kg roller is moved back and forth once, thereby pressing the test piece and the adherend. Then, after standing for 30 minutes, a peel tester (trade name "variable angle peeling tester YSP", manufactured by Asahi Seiko Co., Ltd.) is used to measure the 180° peeling adhesion (tensile speed: 300 mm / min, peeling temperature 23°C).

[0175] In addition, from the viewpoint of achieving good electrical peelability, the 180° peeling adhesive force of the first adhesive layer 11 of the adhesive sheet 10 after voltage application (relative to SUS304 plate, tensile speed 300 mm / min, peeling temperature 23°C) is preferably 1.0 N / 10 mm or less, more preferably 0.5 N / 10 mm or less, and further 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.

[0176] The above-mentioned 180° peel adhesion after voltage application is: after the test piece and the adherend are crimped and left to stand for 30 minutes as described above, a voltage of 10 V is applied for 10 seconds, and then the 180° peel adhesion is measured using a peel tester with voltage applied (tensile speed: 300 mm / min, peeling temperature 23°C).

[0177] In addition, relative to the 180° peel adhesion (hereinafter also referred to as "initial adhesion") of the above-mentioned first adhesive layer 11, the 180° peel adhesion after voltage application (hereinafter also referred to as "adhesion after voltage application") of the above-mentioned first adhesive layer 11 is preferably sufficiently low, and the adhesion reduction rate calculated by the following formula (C) is preferably 60% or more, more preferably 70% or more, and further preferably 80% or more.

[0178] Adhesion force reduction rate (%) = {1-(adhesion force after voltage application / initial adhesion force)}×100(C)

[0179] (Method for producing adhesive sheet)

[0180] In the manufacture of 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 prepared separately. Next, the first composition is applied to the conductive layer 12 of the conductive substrate 12 and dried. Thus, the first adhesive layer 11 can be formed. Next, the second composition is applied to the surface of the conductive substrate 12 on the opposite side to the first adhesive layer 11 and dried. Thus, the second adhesive layer 13 can be formed. For example, the adhesive sheet 10 can be manufactured by operating as described above.

[0181] Alternatively, the adhesive sheet 10 can also be manufactured using the so-called transfer method. Specifically, first, the first adhesive layer 11 and the second adhesive layer 13 are respectively formed on a separator (release liner). Regarding the first adhesive layer 11, the first composition for forming the first adhesive layer 11 is applied to the peeling treatment surface of a specified separator to form a coating film, and the coating film is dried to form. Regarding the second adhesive layer 13, the second composition for forming the second adhesive layer 13 is applied to the peeling treatment surface of a specified separator to form a coating film, and the coating film is dried to form. Next, the first adhesive layer 11 with a separator is attached to the conductive layer 12a of the conductive substrate 12. Next, the second adhesive layer 13 with a separator is attached to the surface of the conductive substrate 12 that is opposite to the first adhesive layer 11. For example, by operating as described above, the adhesive sheet 10 can be manufactured.

[0182] Figure 8In the modified example shown, for example, the surface of the adhesive sheet 10 manufactured by the above method on the side of the first adhesive layer 11 is bonded to the surface of the conductive layer 12a of the conductive substrate 12. Next, the first adhesive layer 11 with a separator is bonded to the surface of the conductive substrate 12b of the conductive substrate 12. For example, the above operation can manufacture Figure 8 The double-sided electrically removable adhesive sheet shown.

[0183] Fig. 9 In the variation shown, Figure 8 The double-sided electrically removable adhesive sheet shown in the figure is similarly, for example, Figure 7 The surface of the electrically peelable adhesive sheet on the first adhesive layer 11 side is attached to the surface of the coating layer 12c side of the conductive substrate 12 including the coating layer 12c. Next, the first adhesive layer 11 with a separator is attached to the surface of the conductive substrate 12 on the substrate layer 12b side. For example, the above operation can produce Fig. 9 The double-sided electrically removable adhesive sheet shown.

[0184] [Conjugate, method for separating the conjugate]

[0185] <First embodiment>

[0186] Next, a first embodiment of a conjugate and a method for separating the conjugate will be described.

[0187] The bonded body of the present embodiment is the following bonded body, which comprises an electrically peelable adhesive sheet, 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 the electrically peelable adhesive sheet comprises: a base material for conducting electricity having a conductive layer; a first adhesive layer formed of an electrically peelable adhesive, the first adhesive layer being formed on the conductive layer of the base material for conducting electricity; and a second adhesive layer being formed on the surface of the base material for conducting electricity on the opposite side to the first adhesive layer, wherein in the bonded body, at least a portion of the first adherend to which the first adhesive layer is attached is conductive, the electrically peelable adhesive sheet comprises an electrode contact portion as a portion to which the adherend is not attached on at least one side, and the surface of the electrode contact portion to which the adherend is not attached has a portion in which the conductive layer is not exposed in at least a portion thereof.

[0188] That is, the joined body of the present embodiment is a joined body in which a first adherend and a second adherend are joined using the above-mentioned pressure-sensitive adhesive sheet.

[0189] When separating the bonded body of this embodiment, the electrode is brought into contact with the first adherend and the conductive layer, a voltage is applied to the first adhesive layer, the adhesive force of the first adhesive layer is reduced, and the first adherend is peeled off from the first adhesive layer, thereby separating. When the electrode is brought into contact with the conductive layer, the electrode is made to penetrate the layer covering the conductive layer in the electrode contact surface in the electrode contact portion, so that the electrode is brought into contact with the conductive layer. That is, for example, Figure 3 In the example shown, the electrode penetrates the first adhesive layer 11 and contacts the conductive layer 12a. Figure 6 In the example shown, the electrode penetrates the second adhesive layer 13 and the base layer 12 b and is brought into contact with the conductive layer 12 a .

[0190] The materials of the first adherend and the second adherend are not particularly limited. At least the portion of the first adherend to which the first adhesive layer is attached has conductivity, and the portion in contact with the electrode has conductivity, and these portions may be electrically connected.

[0191] The voltage applied to the first 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 further preferably 10 V or more. In addition, it is preferably 500 V or less, more preferably 300 V or less, further preferably 100 V or less, and particularly preferably 50 V or less.

[0192] If it is within such a range, the separation operation of the bonded body can be efficiently performed, so it is suitable. For example, if it is within such a range, a power source that is easily available, such as a dry cell, can be used as the power source of the voltage applying device.

[0193] The time for applying the voltage to the first adhesive layer is preferably 300 seconds or less, more preferably 180 seconds or less, further preferably 120 seconds or less, further preferably 60 seconds or less, and particularly preferably 30 seconds or less.

[0194] If it is within such a range, it is suitable from the viewpoint of realizing efficient separation work of the bonded body.

[0195] <Second embodiment>

[0196] Next, a second embodiment of the conjugate and a method for separating the conjugate will be described.

[0197] The bonded body of the present embodiment is the following bonded body, which comprises an electrically peelable adhesive sheet, 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 the electrically peelable adhesive sheet comprises: a conductive substrate having a conductive layer; a first adhesive layer formed of an electrically peelable adhesive, the first adhesive layer being formed on the conductive layer of the conductive substrate; and a second adhesive layer being formed on the surface of the conductive substrate opposite to the first adhesive layer, wherein in the bonded body, at least a portion of the first adherend to which the first adhesive layer is attached is conductive, the first adherend is attached to the entire surface of the electrically peelable adhesive sheet on the first adhesive layer side, and the second adherend is attached to the entire surface on the second adhesive layer side.

[0198] 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 the electrical peeling, so that corrosion of the conductive layer is suppressed.

[0199] When separating the bonded body of this embodiment, the electrode is brought into contact with the first adherend and the conductive layer, a voltage is applied to the first adhesive layer, the adhesive force of the first adhesive layer is reduced, and the first adherend is peeled off from the first adhesive layer, thereby separating. When the electrode is brought into contact with the conductive layer, the electrode is penetrated through the first adherend or the second adherend to bring the electrode into contact with the conductive layer.

[0200] 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 of the first embodiment.

[0201] <Third embodiment>

[0202] Next, a third embodiment of the conjugate and a method for separating the conjugate will be described.

[0203] The bonded body of the present embodiment is a bonded body comprising an electrically-peelable adhesive sheet, a first adherend attached to a second adhesive layer of the electrically-peelable adhesive sheet, and a second adherend attached to another second adhesive layer of the electrically-peelable adhesive sheet, wherein the electrically-peelable adhesive sheet comprises a current-carrying substrate having a conductive layer on both sides of a first adhesive layer formed of an electrically-peelable adhesive, and a second adhesive layer formed on a surface of the current-carrying substrate on the opposite side to the first adhesive layer, wherein the electrically-peelable adhesive sheet comprises an electrode contact portion as a portion to which an adherend is not attached on at least one side, and the surface of the electrode contact portion to which the adherend is not attached has a portion in which the conductive layer is not exposed in at least a part thereof.

[0204] 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 the electrical peeling, so that corrosion of the conductive layer is suppressed.

[0205] When separating the bonded body of this embodiment, the electrode is brought into contact with the first adherend and the conductive layer, a voltage is applied to the first adhesive layer, the adhesive force of the first adhesive layer is reduced, and the first adherend is peeled off from the first adhesive layer, thereby separating. When the electrode is brought into contact with the conductive layer, the electrode is penetrated through the first adherend or the second adherend, and the electrode is brought into contact with at least one of the conductive layers.

[0206] 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 of the first embodiment.

[0207] Example

[0208] Hereinafter, the present invention will be described in more detail using examples, but the present invention is not limited to these examples.

[0209] (Preparation of acrylic polymer solution)

[0210] 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) as monomer components, and 150 parts by mass of ethyl acetate as a polymerization solvent were placed in a separable flask and stirred for 1 hour while introducing nitrogen. After removing oxygen from the polymerization system as described above, 0.2 parts by mass of 2,2'-azobisisobutyronitrile (AIBN) as a polymerization initiator was added, the temperature was raised to 63°C, and the reaction was carried out for 6 hours. Thereafter, ethyl acetate was added to obtain an acrylic polymer solution having a solid content concentration of 40% by mass.

[0211] [Example 1]

[0212] (Preparation of Electro-Releasable Adhesive Layer)

[0213] 100 parts by mass of the acrylic polymer (solution) obtained above, 0.4 parts by mass of the crosslinking agent V-05, 4 parts by mass of the ionic liquid AS-110, additives (3 parts by mass of the adsorption-type corrosion inhibitor AMINE O and 0.3 parts by mass of Irgacor DSSG, 0.8 parts by mass of the chelate-forming metal passivator Irgamet 30), and ethyl acetate were added, stirred and mixed to obtain an adhesive composition (solution) for electrical stripping having a solid content concentration of 25% by mass.

[0214] The obtained electro-peelable adhesive composition (solution) was applied to the release-treated surface of a polyethylene terephthalate separator (trade name "MRF38", manufactured by Mitsubishi Resins Co., Ltd.) with a uniform thickness using an applicator. Next, heat drying was performed at 150° C. for 3 minutes, and the release-treated surface of the polyethylene terephthalate separator (trade name "MRE38", manufactured by Mitsubishi Resins Co., Ltd.) was laminated on the adhesive using a hand roller to obtain an electro-peelable adhesive layer with a thickness of 50 μm.

[0215] The abbreviations of the ionic liquid, the crosslinking agent, the adsorption-type corrosion inhibitor, and the chelate-forming metal passivating agent in Table 1 are as follows.

[0216] (Ionic Liquids)

[0217] AS-110: Cation: 1-ethyl-3-methylimidazolium cation, anion: bis(fluorosulfonyl)imide anion, trade name "ELEXCEL AS-110", manufactured by Daiichi Kogyo Seiyaku Co., Ltd.

[0218] (Crosslinking agent)

[0219] V-05: Polycarbodiimide resin, trade name "CARBODILITE V-05", manufactured by Nisshinbo Chemical Inc.

[0220] (Adsorption type corrosion inhibitor)

[0221] AMINE O: 2-(8-heptadecen-1-yl)-4,5-dihydro-1H-imidazole-1-ethanol, trade name "AMINE O", manufactured by BASF Japan Co., Ltd.

[0222] Irgacor DSSG: Sodium sebacate, trade name "Irgacor DSSG", manufactured by BASF Japan Co., Ltd.

[0223] (Chelate-forming metal passivator)

[0224] Irgamet 30: N,N-bis(2-ethylhexyl)-[(1,2,4-triazol-1-yl)methyl]amine, trade name "Irgamet 30", manufactured by BASF Japan Co., Ltd.

[0225] (Preparation of Electro-Releasable Adhesive Sheet)

[0226] The polyethylene terephthalate separator (MRE38) of the obtained electrically removable adhesive layer was peeled off, and a film with a metal layer (trade name "Metalumy TS", manufactured by Toray Advanced Film Co., Ltd., thickness 50 μm) which is a laminate obtained by laminating a conductive layer (metal layer (aluminum vapor-deposited layer)) and a supporting substrate (polyethylene terephthalate (PET)) in sequence was adhered to the surface of the exposed electrically removable adhesive layer on the conductive layer side to prepare an electrically removable adhesive sheet.

[0227] (Preparation of Conjugate)

[0228] The polyethylene terephthalate separator (MRF38) of the electrically peelable adhesive sheet was peeled off, and a stainless steel plate (SUS316, size: 30 mm×120 mm) as a conductive adherend was placed on the peeled surface. Figure 3 The electrically removable adhesive sheet was attached so that one end of the sheet protruded about 2 mm from the adherend as shown, and pressed with a 2 kg roller moving back and forth once. The sheet was left standing at 23° C. for 30 minutes to obtain a bonded body in which the unexposed portion of the conductive layer was covered with the electrically removable adhesive layer.

[0229] [Example 2]

[0230] An electrically peelable adhesive layer was prepared in the same manner as in Example 1, and the polyethylene terephthalate separator (MRE38) of the obtained electrically peelable adhesive layer was peeled off. On the peeled surface, a film (electrical substrate) having a resin coating layer and a metal layer (trade name "1005CR", manufactured by Toray Advanced Film Co., Ltd., thickness 12 μm) which is a laminate obtained by laminating a resin coating layer (polyester resin layer), a conductive layer (metal layer (aluminum vapor-deposited layer)), and a supporting substrate (PET) in this order was placed on the resin coating side of the film. Figure 7 As shown, the laminate was attached so that one end of the laminate protruded from the electrically removable adhesive layer by about 2 mm to obtain an electrically removable adhesive sheet.

[0231] As an adherend, a stainless steel plate (SUS316, size: 30 mm×120 mm) was prepared as a conductive adherend.

[0232] The polyethylene terephthalate separator (MRF38) of the electrically peelable adhesive sheet obtained above was peeled off, and the above-mentioned conductive adherend was attached to the surface of the peeled electrically peelable adhesive layer side, and a 2 kg roller was used to press back and forth once, and the mixture was left to stand at 23° C. for 30 minutes to obtain a joint body in which the unexposed portion of the conductive layer was covered with a resin coating.

[0233] [Example 3]

[0234] A film with a metal layer (trade name "Metalumy TS", manufactured by Toray Advanced Film Co., Ltd., thickness 50 μm) was prepared as a laminate in which a conductive layer (metal layer (aluminum vapor-deposited layer)) and a supporting substrate (polyethylene terephthalate (PET)) were laminated in this order.

[0235] Next, a Si target (AC: 40 kHz) was installed in an AC sputtering device, and O 2 Gas and N 2 The gas was sputtered simultaneously, thereby forming a 50 nm inorganic coating (SiN x Layer), prepare substrate A. Form SiN x The temperature of the film with the metal layer during the deposition was set to -8°C.

[0236] The polyethylene terephthalate separator (MRE38) of the electrically peelable adhesive layer prepared in the same manner as in Example 1 was peeled off, and the surface of the inorganic coating layer of the substrate A was placed on the surface of the electrically peelable adhesive layer after peeling. Figure 7 As shown, the substrate A was attached so that one end of the substrate A protruded from the electrically removable pressure-sensitive adhesive layer by about 2 mm, thereby obtaining an electrically removable pressure-sensitive adhesive sheet.

[0237] A conductive adherend was attached to the electrically-peelable pressure-sensitive adhesive sheet in the same manner as in Example 2 to obtain a joined body in which the unexposed portion of the conductive layer was covered with the inorganic coating layer.

[0238] [Example 4]

[0239] A film with a metal layer (trade name "Metalumy TS", manufactured by Toray Advanced Film Co., Ltd., thickness 50 μm) was prepared as a laminate in which a conductive layer (metal layer (aluminum vapor-deposited layer)) and a supporting substrate (polyethylene terephthalate (PET)) were laminated in this order.

[0240] Next, a nickel (Ni) target was installed in 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 to prepare a substrate B. The temperature of the substrate film during the formation of the Ni layer was set to -8°C.

[0241] Except that the substrate A was changed to the substrate B, the same operation as in Example 3 was carried out to obtain an electrically removable pressure-sensitive adhesive sheet and a joined body of Example 4.

[0242] [Examples 5 and 6]

[0243] Example 6 and the electrically-peelable pressure-sensitive adhesive sheet and joined body of Example 6 were obtained in the same manner except that the thickness of the inorganic coating layer in Example 3 was changed to 100 nm and 200 nm, respectively.

[0244] [Comparative Example 1]

[0245] An electrically removable adhesive layer was prepared in the same manner as in Example 1, the polyethylene terephthalate separator (MRE38) of the obtained electrically removable adhesive layer was peeled off, and a stainless steel plate (SUS316, size: 30 mm×120 mm) as a conductive adherend was attached to the peeled surface to obtain a laminate.

[0246] As a substrate, a film with a metal layer (trade name "Metalumy S", manufactured by Toray Advanced Film Co., Ltd., thickness 50 μm) was prepared as a laminate in which a conductive layer (metal layer (aluminum vapor-deposited layer)) and a supporting substrate (polyethylene terephthalate (PET)) were laminated in this order.

[0247] The polyethylene terephthalate separator (MRF38) of the laminate obtained above was peeled off, and the surface of the electrically-peelable adhesive layer after peeling was placed on the conductive layer side of the substrate as shown in FIG. Figure 2 The substrate is attached in a manner such that one end of the substrate protrudes from the laminate by about 2 mm as shown, and is pressed by moving a 2 kg roller back and forth once. The laminate is left to stand at 23° C. for 30 minutes to obtain a joint body in which the surface of the electrode contact portion to which the adherend is not attached does not have a portion in which the conductive layer is not exposed in at least a portion of the surface.

[0248] <Corrosion Evaluation>

[0249] The bonded bodies obtained in Examples 1 to 6 and Comparative Example 1 were visually evaluated for corrosion of the conductive layer after being stored in a constant temperature and humidity device set at 60° C. and 90% for one week. The corrosion evaluation was performed by visual inspection.

[0250] The results obtained for Examples 1 to 4 and Comparative Example 1 are shown in Table 1. Regarding Examples 5 and 6, the presence or absence of corrosion was "none".

[0251] [Table 1]

[0252]

[0253] As mentioned above, although the preferred embodiment of the present invention has been described, the present invention is not limited to the above-mentioned embodiment, and various modifications and substitutions can be added to the above-mentioned embodiment within the scope not departing from the scope of the present invention.

[0254] It should be noted that the present application is based on the Japanese patent application (Japanese Patent Application No. 2019-147408) filed on August 9, 2019, and the contents thereof are incorporated herein by reference.

[0255] Description of Reference Numerals

[0256] 1 electrically peelable adhesive sheet; 2, 3 adherends; 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 substrate for conducting electricity; 12a conductive layer; 12b substrate layer; 12c coating layer; 13 second adhesive layer; 14 electrode contact portion; 15 first adherend; 16 second adherend; 17 extended protrusion; 20 electrically peelable adhesive sheet; 21 first adhesive layer; 22 substrate for conducting electricity; 22a conductive layer; 23 second adhesive layer; 24 electrode contact portion; 25 first adherend; 26 second adherend.

Claims

1. An electrically peelable adhesive sheet comprising: A current-carrying substrate having a conductive layer; a first adhesive layer formed of an adhesive for electrical peeling, the first adhesive layer being formed on the conductive layer of the current-carrying substrate; and a second adhesive layer formed on a surface of the conducting substrate opposite to the first adhesive layer, The electrically removable pressure-sensitive adhesive sheet has an electrode contact portion on at least one side thereof, which is a portion not to be attached to an adherend. The surface of the electrode contact portion to which the adherend is not attached has a portion where the conductive layer is not exposed in at least a portion thereof. The current-carrying substrate further comprises a coating layer, The coating layer is a layer mainly composed of resin or inorganic substances. The unexposed portion of the conductive layer is covered by the coating layer.

2. The electrically removable adhesive sheet according to claim 1, in, The conductive layer is not exposed on the entire surface of the electrode contact portion to which the adherend is not attached.

3. The electrically removable adhesive sheet according to claim 1 or 2, in, In the electrode contact portion, the surface not attached to the adherend is the surface on the first adhesive layer side, and the unexposed portion of the conductive layer is covered with the first adhesive layer.

4. A bonded body comprising an electrically removable adhesive sheet, a first adherend attached to a first adhesive layer of the electrically removable adhesive sheet, and a second adherend attached to a second adhesive layer of the electrically removable adhesive sheet, wherein the electrically removable adhesive sheet comprises: A current-carrying substrate having a conductive layer; a first adhesive layer formed of an adhesive for electrical peeling, the first adhesive layer being formed on the conductive layer of the current-carrying substrate; and a second adhesive layer formed on a surface of the conducting substrate opposite to the first adhesive layer, In the conjugate, At least a portion of the first adherend to which the first adhesive layer is attached has electrical conductivity. The electrically removable pressure-sensitive adhesive sheet has an electrode contact portion as a portion not attached to an adherend on at least one side, and the surface of the electrode contact portion not attached to an adherend has a portion where the conductive layer is not exposed in at least a part thereof. The current-carrying substrate further comprises a coating layer, The coating layer is a layer mainly composed of resin or inorganic substances. The unexposed portion of the conductive layer is covered by the coating layer.

5. The conjugate according to claim 4, in, The conductive layer is not exposed on the entire surface of the electrode contact portion to which the adherend is not attached.

6. The conjugate according to claim 4 or 5, in, In the electrode contact portion, the surface not attached to the adherend is the surface on the first adhesive layer side, and the unexposed portion of the conductive layer is covered with the first adhesive layer.

7. The method for separating a conjugate according to any one of claims 4 to 6, wherein include: In the portion of the electrode contact portion where the conductive layer is not exposed on the surface of the electrode contact portion not to be attached, an electrode is brought into contact with the conductive layer by penetrating through a layer covering the conductive layer, thereby applying a voltage to the first adhesive layer.

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