Conductive base material, adhesive sheet, and bonded body

Abstract

The present invention relates to a conductive base material which exhibits excellent resistance to heat and humidity and can be repeatedly used, and an adhesive sheet including the conductive base material. The present invention relates to a conductive base material that comprises a base material, and a conductive layer having a metal layer that includes at least one type of metal selected from metals having a standard electrode potential of -1.67 [V vs. SHE] or more and an alloy containing said metal.

Description

Conductive substrate, adhesive sheet, and bond

[0001] The present invention relates to a conductive substrate, an adhesive sheet containing the conductive substrate, and a bond between the adhesive sheet and an adherend.

[0002] In electronic component manufacturing processes, there is a growing demand for rework to improve yield and for recycling, which involves disassembling and recovering components after use. To meet these demands, double-sided adhesive sheets that possess both a certain level of adhesive strength and a certain level of release properties are sometimes used to join materials together in electronic component manufacturing processes.

[0003] As a double-sided adhesive sheet that achieves peelability by applying voltage and the adhesive strength described above, an adhesive sheet (electro-peelable adhesive sheet) is known that comprises an electro-peelable adhesive layer formed from an electro-peelable adhesive composition containing a base polymer, an ionic liquid, a water-soluble polymer, and a corrosion inhibitor (Patent Document 1). For example, Patent Document 1 describes an electro-peelable adhesive sheet that uses an electrically conductive substrate having a metal vapor-deposited layer on the substrate, and comprises a substrate, a conductive layer (metal vapor-deposited layer), and an electro-peelable adhesive layer whose adhesive strength decreases when voltage is applied, in this order. According to Patent Document 1, when the electro-peelable adhesive layer is attached to a conductive adherend, a method is described in which a voltage is applied to the adhesive layer via the conductive adherend to the conductive adherend and the electrically conductive substrate to peel it off from the conductive adherend.

[0004] International Publication No. 2022 / 163593

[0005] Our inventors have investigated and found that conventional adhesive tapes described in Patent Document 1 suffer from appearance defects due to repeated use, such as the metal vapor-deposited film contained in the conductive substrate within the adhesive sheet peeling off from the substrate, or corrosion of the metal vapor-deposited film after being exposed to a humid and hot environment for a long period of time.

[0006] The present invention was completed in view of the above, and aims to provide a conductive substrate with excellent resistance to moist heat and reusability, and an adhesive sheet containing the conductive substrate.

[0007] As a result of repeated studies by the present inventors, it has been found that the above-mentioned problems can be solved by using a conductive substrate comprising a substrate and a conductive layer, wherein the conductive layer has a metal layer containing a predetermined metal.

[0008] The means for solving the above problems are as follows: [1] A conductive substrate comprising a base material and a conductive layer having a metal layer containing at least one selected from a metal having a standard electrode potential of -1.67 [V vs. SHE] or higher, and an alloy containing the said metal. [2] The conductive substrate according to [1], wherein the metal having a standard electrode potential of -1.67 [V vs. SHE] or higher is at least one selected from noble metals, Cr, Ni, Nb, Ti, V, W, Mo, and Zr. [3] The conductive substrate according to claim 1, wherein the crystal lattice of the metal having a standard electrode potential of -1.67 [V vs. SHE] or higher is a face-centered cubic lattice. [4] The conductive substrate according to [1], wherein the metal layer is a metal layer containing a Ni alloy. [5] The conductive substrate according to [1], wherein the surface of the conductive layer opposite to the base material is a layer made of a Ni alloy. [6] The conductive substrate according to [4], wherein the Ni alloy is a NiCr alloy, a NiV alloy, a NiTi alloy, or a NiNb alloy. [7] The conductive substrate according to [4], wherein the Ni alloy is any one of a NiCr alloy with a Cr content of more than 0 atm% and 50 atm% or less, a NiV alloy with a V content of more than 0 atm% and 50 atm% or less, a NiTi alloy with a Ti content of more than 0 atm% and 50 atm% or less, or a NiNb alloy with a Nb content of more than 0 atm% and 50 atm% or less. [8] The conductive substrate according to [4], wherein the Ni alloy is any one of the following: a NiCr alloy with a Cr content of more than 0 atm% and 22 atm% or less; a NiV alloy with a V content of more than 0 atm% and 22 atm% or less; a NiTi alloy with a Ti content of more than 0 atm% and 22 atm% or less; or a NiNb alloy with a Nb content of more than 0 atm% and 22 atm% or less. [9] The conductive substrate according to [4], wherein the Ni alloy is any one of the following: a NiCr alloy with a Cr content of more than 0 atm% and 15 atm% or less; a NiV alloy with a V content of more than 0 atm% and 15 atm% or less; a NiTi alloy with a Ti content of more than 0 atm% and 15 atm% or less; or a NiNb alloy with a Nb content of more than 0 atm% and 15 atm% or less.

[10] The conductive substrate according to [1], wherein the metal layer consists of a single layer.

[11] The conductive substrate according to [1], wherein the conductive layer further comprises a silicon oxide layer.

[12] The conductive substrate according to [1], wherein the surface of the substrate is treated for easy adhesion.

[13] The conductive substrate according to [1], further comprising an easy-adhesion layer.

[14] The conductive substrate according to [1], for electrolytic release and / or for fixing components in electrical and electronic equipment.

[15] The conductive substrate according to [9], for electrolytic release and / or for fixing components in electrical and electronic equipment.

[16] An adhesive sheet comprising the conductive substrate according to any one of [1] to

[15] and an adhesive layer.

[17] An electrolytically released adhesive sheet comprising the conductive substrate according to any one of [1] to [6] or

[10] to

[14] and an electrolytically released adhesive layer whose adhesive strength decreases when a voltage is applied, wherein the conductive layer side surface of the conductive substrate and the electrolytically released adhesive layer are in contact.

[18] An electropenetrating adhesive sheet comprising a conductive substrate according to any one of [7] to [9] or

[15] and an electropenetrating adhesive layer whose adhesive strength decreases when a voltage is applied, wherein the conductive substrate's surface on the conductive layer side and the electropenetrating adhesive layer are in contact.

[19] An electropenetrating adhesive sheet comprising a conductive substrate according to any one of [1] to

[12] or

[14] and an electropenetrating adhesive layer whose adhesive strength decreases when a voltage is applied, wherein the conductive substrate further comprises an easy-adhesion layer on the conductive layer side, and the easy-adhesion layer and the electropenetrating adhesive layer are in contact.

[20] A joint comprising the electropenetrating adhesive sheet according to

[17] and a conductive material, wherein the electropenetrating adhesive layer is attached to the conductive material.

[21] A joint comprising the electropenetrating adhesive sheet according to

[18] and a conductive material, wherein the electropenetrating adhesive layer is attached to the conductive material.

[0009] The present invention provides a conductive substrate with excellent resistance to moist heat and reusability, as well as an adhesive sheet containing the conductive substrate.

[0010] Figure 1 is a cross-sectional view showing an example of a conductive substrate according to an embodiment of the present invention. Figure 2 is a cross-sectional view showing another example of a conductive substrate according to an embodiment of the present invention. Figure 3 is a cross-sectional view showing an example of a laminated structure of an adhesive sheet according to an embodiment of the present invention. Figure 4 is a cross-sectional view showing another example of a laminated structure of an adhesive sheet according to an embodiment of the present invention. Figure 5 is a cross-sectional view showing an overview of the method of the 180° peel test in the example.

[0011] The embodiments for carrying out the present invention will be described in detail below. However, the present invention is not limited to the embodiments described below. In this specification, "adhesive" is used to mean a tackling agent (also called a "pressure-sensitive adhesive").

[0012] [Conductive Substrate] The conductive substrate of this embodiment comprises a substrate and a conductive layer having a metal layer containing at least one metal selected from a metal having a standard electrode potential of -1.67 [V vs. SHE] or higher, and an alloy containing the said metal. The standard electrode potential of the metal contained in the metal layer is preferably -1.50 [V vs. SHE] or higher, more preferably -1.20 [V vs. SHE] or higher, even more preferably -0.90 [V vs. SHE] or higher, and even more preferably -0.75 [V vs. SHE] or higher. The standard electrode potential may be measured using any suitable measuring device, and values ​​described in literature such as Chemical Handbook Basic Edition II, Revised 4th Edition, pp. 464-468 ​​(edited by the Chemical Society of Japan, Maruzen Publishing) may be referred to. The structure of the conductive substrate of this embodiment is not particularly limited as long as the above requirements are met, but for example, the conductive substrate 5 shown in Figure 1 is preferred. Furthermore, if the conductive substrate is a single-layer or laminated structure of conductive material, the surface resistance value is, for example, 1.0 × 10⁻⁶. ４ Ω / □ or less, preferably 1.0 × 10 ３The resistance is less than or equal to Ω / □. The surface resistance can be calculated by dividing the resistivity measured by the four-terminal method by the thickness of the conductive substrate, in accordance with JIS K 7194 (1994). Furthermore, the surface resistance of the conductive layer 4 can be selected according to the purpose and conditions of use, i.e., the applied voltage conditions for peeling (whether peeling is to be done with a high voltage or a low voltage). Lowering the surface resistance of the conductive layer 4 tends to lower the voltage required for peeling. For example, the surface resistance is 5.0 × 10 ２ It can also be less than or equal to Ω / □, and 1.0 × 10 ２ It may be less than or equal to Ω / □, less than or equal to 50Ω / □, less than or equal to 40Ω / □, or less than or equal to 30Ω / □.

[0013] <Conductive Layer> The conductive substrate 5 of this embodiment includes a conductive layer 4 having a metal layer 6 containing at least one metal (hereinafter also referred to as a specific metal) selected from a metal with a standard electrode potential of -1.67 [V vs. SHE] or higher, and an alloy containing the said metal. By having a metal layer containing a metal with high oxidation resistance in the conductive layer, a highly durable conductive substrate can be obtained.

[0014] Metals with a standard electrode potential of -1.67 [V vs. SHE] or higher include precious metals such as gold (Au), platinum (Pt), and silver (Ag) due to their excellent corrosion resistance from chemical stability, and metals such as chromium (Cr), nickel (Ni), niobium (Nb), titanium (Ti), vanadium (V), tungsten (W), molybdenum (Mo), zirconium (Zr), iron (Fe), tin (Sn), lead (Pb), and indium (In) due to their excellent corrosion resistance from the formation of an oxide film. Among these, precious metals, Cr, Ni, Nb, Ti, V, W, Mo, or Zr are preferred, and Cr, Ni, Nb, or Ti are more preferred. It is preferable that the metal with a standard electrode potential of -1.67 [V vs. SHE] or higher is at least one selected from precious metals, Cr, Ni, Nb, Ti, V, W, Mo, Sn, Fe, and Zr. From the viewpoint of having good resistance to bending deformation, in some embodiments, the metal with a standard electrode potential of -1.67 [V vs. SHE] or higher is preferably a face-centered cubic crystal lattice, and of the metal with a face-centered cubic crystal lattice, it is more preferably Ni. From the viewpoint of achieving both good resistance to bending deformation and corrosion resistance, the metal layer is preferably a single layer of a metal having a standard electrode potential of -1.67 [V vs. SHE] or higher, and more preferably Ni.

[0015] The specific metals included in the metal layer 6 include the elemental metals mentioned above, as well as alloys containing these metals. Preferably, the alloy is one in which the above-mentioned metals are the main component. Specifically, it is preferable that the alloy contains 50 atm% or more of the above-mentioned metals. Examples of alloys include Ni alloys, Ti alloys, Cr alloys, Sn alloys, and Fe alloys such as SUS304, due to their excellent corrosion resistance resulting from the formation of an oxide film. Among these, Ni alloys are particularly preferred. The specific metal included in the metal layer 6 is preferably a Ni alloy.

[0016] Examples of Ni alloys include NiCr alloys, NiV alloys, NiTi alloys, NiNb alloys, NiSn alloys, and NiP, which exhibit excellent corrosion resistance due to the formation of an oxide film. NiCr alloys, NiV alloys, NiTi alloys, or NiNb alloys are preferred.

[0017] When the Ni alloy is a NiCr alloy, from the viewpoint of achieving excellent corrosion resistance due to the formation of an oxide film and easier to realize a conductive substrate with low remanent magnetization, in some embodiments, the Cr content in the NiCr alloy is, for example, greater than 0 atm%, may be 0.1 atm% or more, may be 2.0 atm% or more, preferably 4.0 atm% or more, more preferably 6.0 atm% or more, even more preferably 7.0 atm% or more, and from the viewpoint of manufacturing cost, preferably 8 atm% or more. Furthermore, from the viewpoint of obtaining a conductive substrate with low resistance and good resistance to bending deformation, the Cr content in the NiCr alloy is preferably 50 atm% or less, more preferably 38 atm% or less, even more preferably 25 atm% or less, and even more preferably 23 atm% or less. Furthermore, from the viewpoint of achieving a good balance between low resistance, corrosion resistance, and bending deformation resistance, in some embodiments, the Cr content in the NiCr alloy is preferably 22 atm% or less, more preferably 21 atm% or less, more preferably 20 atm% or less, and even more preferably 18 atm% or less. From the viewpoint of having particularly excellent bending deformation resistance, in some embodiments, the Cr content in the NiCr alloy is preferably 15 atm% or less, more preferably 13 atm% or less, even more preferably 10 atm% or less, even more preferably 9 atm% or less, and particularly preferably 8 atm% or less.

[0018] When the Ni alloy is a NiV alloy, from the viewpoint of achieving excellent corrosion resistance due to the formation of an oxide film and easier to realize a conductive substrate with low remanent magnetization, in some embodiments, the V content in the NiV alloy is, for example, greater than 0 atm%, may be 0.1 atm% or more, may be 2.0 atm% or more, preferably 4.0 atm% or more, more preferably 6.0 atm% or more, even more preferably 7.0 atm% or more, and from the viewpoint of manufacturing cost, preferably 8 atm% or more. Furthermore, from the viewpoint of obtaining a conductive substrate with low resistance and good resistance to bending deformation, the V content in the NiV alloy is preferably 50 atm% or less, more preferably 38 atm% or less, even more preferably 25 atm% or less, and even more preferably 23 atm% or less. Furthermore, from the viewpoint of achieving a good balance between low resistance, corrosion resistance, and bending deformation resistance, in some embodiments, the V content in the NiV alloy is preferably 22 atm% or less, more preferably 21 atm% or less, more preferably 20 atm% or less, and even more preferably 18 atm% or less. From the viewpoint of having particularly excellent bending deformation resistance, in some embodiments, the V content in the NiV alloy is preferably 15 atm% or less, more preferably 13 atm% or less, even more preferably 11 atm% or less, even more preferably 10 atm% or less, even more preferably 9 atm% or less, and most preferably 8 atm% or less.

[0019] When the Ni alloy is a NiTi alloy, from the viewpoint of achieving excellent corrosion resistance due to the formation of an oxide film and easier to realize a conductive substrate with low remanent magnetization, in some embodiments, the Ti content in the NiTi alloy is, for example, greater than 0 atm%, may be 0.1 atm% or more, may be 2.0 atm% or more, preferably 4.0 atm% or more, more preferably 6.0 atm% or more, even more preferably 7.0 atm% or more, and from the viewpoint of manufacturing cost, preferably 8 atm% or more. Furthermore, from the viewpoint of obtaining a conductive substrate with low resistance and good resistance to bending deformation, the Ti content in the NiTi alloy is preferably 50 atm% or less, more preferably 38 atm% or less, even more preferably 25 atm% or less, and even more preferably 23 atm% or less. Furthermore, from the viewpoint of achieving a good balance between low resistance, corrosion resistance, and bending deformation resistance, in some embodiments, the Ti content in the NiTi alloy is preferably 22 atm% or less, more preferably 21 atm% or less, more preferably 20 atm% or less, and even more preferably 18 atm% or less. From the viewpoint of having particularly excellent bending deformation resistance, in some embodiments, the Ti content in the NiTi alloy is preferably 15 atm% or less, more preferably 13 atm% or less, even more preferably 11 atm% or less, even more preferably 10 atm% or less, particularly preferably 9 atm% or less, and most preferably 8 atm% or less.

[0020] When the Ni alloy is a NiNb alloy, from the viewpoint of achieving excellent corrosion resistance due to the formation of an oxide film and easier to realize a conductive substrate with low remanent magnetization, in some embodiments, the Nb content in the NiNb alloy is, for example, greater than 0 atm%, may be 0.1 atm% or more, may be 2.0 atm% or more, preferably 4.0 atm% or more, more preferably 6.0 atm% or more, even more preferably 7.0 atm% or more, and from the viewpoint of manufacturing cost, preferably 8 atm% or more. Furthermore, from the viewpoint of obtaining a conductive substrate with low resistance and good resistance to bending deformation, the Nb content in the NiNb alloy is preferably 50 atm% or less, more preferably 38 atm% or less, even more preferably 25 atm% or less, and even more preferably 23 atm% or less. Furthermore, in some embodiments, from the viewpoint of achieving a good balance between low resistance, corrosion resistance, and bending deformation resistance, the Nb content in the NiNb alloy is preferably 22 atm% or less, more preferably 21 atm% or less, even more preferably 20 atm% or less, and still more preferably 18 atm% or less. In some embodiments, from the viewpoint of having particularly excellent bending deformation resistance, the Nb content in the NiNb alloy is preferably 15 atm% or less, more preferably 13 atm% or less, even more preferably 11 atm% or less, even more preferably 10 atm% or less, particularly preferably 9 atm% or less, and most preferably 8 atm% or less.

[0021] From the viewpoint of obtaining a conductive substrate with excellent corrosion resistance due to the formation of an oxide film and low residual magnetization, the Ni alloy is preferably, in some embodiments, one of the following: a NiCr alloy with a Cr content of more than 0 atm% and 50 atm% or less; a NiV alloy with a V content of more than 0 atm% and 50 atm% or less; a NiTi alloy with a Ti content of more than 0 atm% and 50 atm% or less; or a NiNb alloy with a Nb content of more than 0 atm% and 50 atm% or less.

[0022] From the viewpoint of obtaining a well-balanced conductive substrate with low resistance, excellent corrosion resistance due to the formation of an oxide film, excellent resistance to bending deformation, and low residual magnetization, the Ni alloy is more preferably one of the following in some embodiments: a NiCr alloy with a Cr content of more than 0 atm% and 22 atm% or less, a NiV alloy with a V content of more than 0 atm% and 22 atm% or less, a NiTi alloy with a Ti content of more than 0 atm% and 22 atm% or less, or a NiNb alloy with a Nb content of more than 0 atm% and 22 atm% or less.

[0023] In some embodiments, the Ni alloy is more preferably a NiCr alloy having a Cr content of more than 0 atm% and 15 atm% or less, a NiV alloy having a V content of more than 0 atm% and 15 atm% or less, a NiTi alloy having a Ti content of more than 0 atm% and 15 atm% or less, or a NiNb alloy having an Nb content of more than 0 atm% and 15 atm% or less, from the viewpoint of obtaining a conductive substrate with particularly excellent resistance to bending deformation.

[0024] In this embodiment, the metal layer 6 may contain only one of the specified metals, or it may contain two or more. The metal layer 6 may or may not contain metals or elements other than the specified metals. Examples of metals other than the specified metals include iron, molybdenum, indium, silver, and copper. Examples of elements other than the specified metals include nitrogen, oxygen, and hydrogen. Furthermore, the metal layer 6 may or may not contain metals other than the specified metals, but it is preferable that it does not contain them. The total content of the specified metals in the metal layer 6 of this embodiment is preferably 80 atm% or more, and more preferably 90 atm% or more.

[0025] In this embodiment, the metal layer 6 may be formed from only one layer, or from two or more layers stacked together, but it is preferable that it is formed from only one layer, i.e., a single layer.

[0026] In this embodiment, it is preferable that the conductive substrate 5 has a layer made of a Ni alloy (metal layer 6 made of a Ni alloy) on the surface of the conductive layer 4 opposite to the substrate 3. For example, if the Ni alloy is NiCr, both conductivity and corrosion resistance can be achieved through the conductivity provided by Ni and the corrosion resistance provided by the dense passive film of Cr.

[0027] The metal layer 6 is not particularly limited as long as it is a layer containing the specified metal described above, but it may be a metal-based substrate such as a metal foil or metal plate, or a metal film sputtered or deposited on the substrate 3.

[0028] When the metal layer 6 is a metal film sputtered or deposited on the substrate 3, the thickness of the metal layer 6 is preferably 0.001 μm or more and 0.5 μm or less. If the thickness of the metal layer 6 is 0.5 μm or less, peeling of the film from the substrate due to stress can be suppressed. From the viewpoint of productivity, the thickness of the metal layer 6 is preferably 0.5 μm or less, more preferably 0.3 μm or less, and even more preferably 0.2 μm or less. Furthermore, from the viewpoint of further suppressing peeling of the film from the substrate due to stress, the thickness of the metal layer 6 is preferably 0.1 μm or less, more preferably 0.08 μm or less, and even more preferably 0.06 μm or less. From the viewpoint of making it easier to form the metal layer 6 as a continuous film and to easily obtain sufficient conductivity, the thickness of the metal layer 6 is preferably 0.0025 μm or more, more preferably 0.003 μm or more, even more preferably 0.005 μm or more, and even more preferably 0.01 μm or more. Furthermore, the thickness of the metal layer 6 can be selected according to the intended use and usage conditions, that is, the applied voltage conditions under which peeling is desired (whether peeling is desired with a high voltage or a low voltage), that is, the surface resistance value required for the conductive substrate. For example, it may be 0.05 μm or less, 0.04 μm or less, or 0.035 μm or less. The technology disclosed herein can preferably be implemented in a manner in which the thickness of the metal layer 6 is in the range of 0.003 μm or more and 0.1 μm or less, more preferably 0.01 μm or more and 0.06 μm or less.

[0029] In this embodiment, the conductive layer 4 may consist only of the metal layer 6 as shown in Figure 1, but as shown in Figure 2, it is also preferable to include a base layer 7 on the laminated surface of the metal layer 6 with the substrate 3, from the viewpoint of improving adhesion to the substrate 3. Examples of base layers include a silicon oxide layer, Cr, Ti, etc. It is preferable that the conductive layer 4 further includes a silicon oxide layer. The silicon oxide layer can be formed by forming a silicon (Si) film and then oxidizing it in the atmosphere. At that time, it is easier to form Si-O bonds with the substrate, so adhesion can be particularly improved.

[0030] The thickness of the underlayer is preferably 0.001 μm or more and 0.05 μm or less. If the thickness of the underlayer is 0.001 μm or more, it becomes easier to form a continuous film of the metal layer. Also, if it is 0.05 μm or less, peeling of the metal layer from the substrate due to stress can be suppressed. From the viewpoint of productivity, the thickness of the underlayer is preferably 0.05 μm or less, and more preferably 0.03 μm or less. Also, from the viewpoint of further suppressing peeling of the film from the substrate due to stress, the thickness of the underlayer is preferably 0.02 μm or less, more preferably 0.01 μm or less, and even more preferably 0.005 μm or less. From the viewpoint of making it easier to form the underlayer as a continuous film and to obtain uniform adhesion in the plane direction, the thickness of the underlayer is preferably 0.001 μm or more, more preferably 0.002 μm or more, and even more preferably 0.003 μm or more.

[0031] The thickness of the conductive layer 4 is preferably 0.001 μm or more and 1000 μm or less. From the viewpoint of productivity, the upper limit of the thickness is more preferably 500 μm, even more preferably 300 μm, even more preferably 50 μm, even more preferably 10 μm, and the lower limit is more preferably 0.003 μm, even more preferably 0.005 μm, and even more preferably 0.01 μm.

[0032] The thicknesses of the conductive layer, metal layer, and substrate layer can be measured by preparing a cross-section of the laminate containing the layers to be measured using the FIB microsampling method and performing FE-TEM observation. Furthermore, the composition of the conductive layer can be confirmed by elemental analysis using TEM-EDX measurement. The specific measurement procedures and conditions for the thicknesses of the conductive layer, metal layer, and substrate layer can be set according to the measurement conditions described in the examples below.

[0033] In this embodiment, the conductive substrate 5 preferably further comprises an easy-adhesion layer. The conductive substrate 5 may have the easy-adhesion layer at any location, or it may be on the surface of the substrate 3 or the conductive layer 4. Alternatively, the conductive substrate 5 may have the easy-adhesion layer between the substrate 3, the conductive layer 4, and any other layers optionally provided by the conductive substrate 5, or on the surface of the conductive substrate 5. The conductive substrate 5 in this embodiment may have multiple easy-adhesion layers. The conductive substrate 5 preferably has the easy-adhesion layer on the surface of the conductive layer 4, and in some embodiments that emphasize adhesion with the adhesive layer described later, it is preferable to have the easy-adhesion layer on the surface of the conductive layer 4 opposite to the substrate 3 side. From the viewpoint of improving adhesion with the adhesive layer, it is preferable to provide the easy-adhesion layer on the surface of the conductive substrate 5 opposite to the substrate 3 side of the conductive layer 4, and it is preferable that the easy-adhesion layer on the surface of the conductive layer 4 and the conductive layer 4 are adjacent to each other. Examples of the easy-adhesion layer include a layer mainly composed of at least one resin selected from polyester resins, acrylic resins, epoxy resins, and urethane resins, or a carbon layer, with a carbon layer being preferred.

[0034] The layer mainly composed of resin can be formed by applying a resin composition mainly composed of a resin component and drying and / or curing it. The thickness of the layer mainly composed of resin is preferably 0.01 μm or more and 5 μm or less. From the viewpoint of productivity, the upper limit of the thickness is more preferably 2 μm, still more preferably 1 μm, still more preferably 0.5 μm, still more preferably 0.2 μm, still more preferably 0.17 μm, still more preferably 0.15 μm, still more preferably 0.13 μm, still more preferably 0.1 μm, and the lower limit is more preferably 0.015 μm, still more preferably 0.02 μm, still more preferably 0.03 μm, still more preferably 0.05 μm.

[0035] The carbon layer is not particularly limited as long as it is formed of carbon, and can be set so as to realize the conductive base material 5 that can achieve both desired conductivity and adhesion. In some embodiments where the conductive base material 5 is applied to the electrically peelable adhesive sheet described later, from the viewpoint of easily achieving both desired electrical peelability and good adhesion, the carbon layer is sp ２ bonding and sp ３ [[ID= / / ID=7]]bonding and is preferably formed of carbon atoms having bonding. When the carbon layer is formed of carbon atoms having sp ２ bonding and sp ３ bonding, the carbon layer is a layer having a graphite-type structure and a diamond-type structure.

[0036] sp ２ bonding and sp ３ The carbon layer formed of carbon atoms having bonding can preferably be formed by a dry method. Examples of the dry method include a PVD method (physical vapor deposition method) and a CVD method (chemical vapor deposition method), and preferably, the PVD method is included. Among the PVD methods, the sputtering method is more preferable.

[0037] Other carbon layers may be formed by applying a paste containing carbon particles and drying and / or curing it. Examples of carbon particles include graphite, carbon black, acetylene black, Ketjenblack, carbon nanofibers, carbon nanotubes, graphene, fullerene, carbon nanocoils, carbon microcoils, carbon beads, and carbon fibers. Among these, carbon black is preferred due to its low cost and easy availability.

[0038] The thickness of the carbon layer is preferably 0.001 μm or more and 1000 μm or less. From the viewpoint of productivity, the upper limit of the thickness is more preferably 500 μm, even more preferably 300 μm, even more preferably 100 μm, even more preferably 50 μm, and even more preferably 10 μm, and the lower limit is more preferably 0.002 μm and even more preferably 0.003 μm.

[0039] The carbon layer is sp ２ Bonding and sp ３ When formed from carbon atoms having bonds, the thickness of the carbon layer is preferably 0.001 μm or more, more preferably 0.002 μm or more, even more preferably 0.003 μm or more, and the upper limit of the thickness is preferably 0.2 μm or less, more preferably 0.1 μm or less, even more preferably 0.07 μm or less, particularly preferably 0.05 μm or less, and most preferably 0.04 μm or less. It is preferable for the thickness of the carbon layer to be above the lower limit from the viewpoint of adhesion with the adhesive layer. On the other hand, it is preferable for the thickness of the carbon layer to be below the upper limit from the viewpoint of electropenetration. Furthermore, the thickness of the carbon layer can be selected according to the purpose of use and usage conditions, i.e., the applied voltage conditions for peeling (whether peeling is desired with high voltage or low voltage). Reducing the thickness of the carbon layer tends to lower the voltage required for peeling. The thickness of the carbon layer may be, for example, 0.03 μm or less, 0.02 μm or less, 0.015 μm or less, 0.013 μm or less, 0.01 μm or less, or 0.008 μm or less.

[0040] The thickness of the easily adhering layer can be calculated by measuring its X-ray reflectance, or by preparing a cross-section using the above-mentioned FIB microsampling method and performing FE-TEM observation.

[0041] <Substrate> The conductive substrate 5 of this embodiment has a substrate 3. The substrate 3 is preferably a plastic substrate, and examples include plastic substrates such as films and sheets made of various plastics (polyolefin resins such as polyethylene and polypropylene, polyester resins such as polyethylene terephthalate, acrylic resins such as polymethyl methacrylate, etc.), paper substrates such as paper, fiber substrates such as cloth and nonwoven fabric, foam substrates of various plastics (polyolefin resins such as ethylene, polypropylene, ethylene-propylene copolymer polymer, ethylene-vinyl acetate copolymer polymer; polyurethane resins; rubber resins such as acrylic rubber and other elastomers, etc.), and laminates thereof. The substrate may have a single layer form or a multi-layer form.

[0042] The substrate may be subjected to various treatments as needed, such as back treatment, antistatic treatment, and undercoating. Preferably, the substrate surface is treated for easy adhesion, and it is preferable that the surface on the conductive layer 4 side is treated for easy adhesion. Examples of easy adhesion treatments for the substrate surface include plasma treatment, roughening treatment, and providing an easy adhesion layer. It is also preferable that the substrate has an easy adhesion layer on its surface. Examples of an easy adhesion layer on the substrate surface include those containing a resin such as polyester.

[0043] The thickness of the base material 3 is preferably 10 μm or more and 1000 μm or less. The upper limit of the thickness is more preferably 500 μm, even more preferably 300 μm, particularly preferably 100 μm, even more preferably 70 μm, even more preferably 50 μm, even more preferably 40 μm, and the lower limit is more preferably 12 μm, even more preferably 20 μm.

[0044] The thickness of the conductive substrate 5 is preferably 10 μm or more and 1000 μm or less. The upper limit of the thickness is more preferably 500 μm, even more preferably 300 μm, and particularly preferably 100 μm, while the lower limit is more preferably 12 μm, and even more preferably 25 μm.

[0045] <Corrosion> The conductive substrate according to the embodiment of the present invention, which contains the metal layer described above, has high corrosion resistance. Therefore, even when the conductive substrate of the present invention is placed in a high-temperature, high-humidity environment while bonded to an adhesive composition, corrosion of the surface of the metal layer is unlikely to occur. Corrosion of the surface of the metal layer can be determined by the fact that the conductive layer of the conductive substrate loses its metallic luster and becomes transparent (discoloration). Specifically, the bonded body described later in this embodiment is stored in a constant temperature and humidity chamber at 60°C and 90% RH for 504 hours (3 w), and after removal, it is left to stand at 22°C and 50% RH for 72 hours. The bonded body after storage can be visually evaluated based on the evaluation criteria described in the example. In this embodiment, it is preferable that the conductive substrate does not have any corroded parts due to appearance issues.

[0046] <Discoloration> The conductive substrate according to the embodiment of the present invention containing the above-described metal layer has high corrosion resistance. Therefore, even when the conductive substrate of the present invention is placed in a high-temperature, high-humidity environment while bonded to an adhesive composition, discoloration of the surface of the metal layer is unlikely to occur. Discoloration of the surface of the metal layer can be determined by the fact that the conductive substrate has not lost its metallic luster, but its original color and / or luster has changed. Specifically, the bonded body described later in this embodiment is stored in a constant temperature and humidity chamber at 60°C and 90% RH for 504 hours (3 w), and after removal, it is left to stand at 22°C and 50% RH for 72 hours. The bonded body after storage can be visually evaluated based on the judgment criteria described in the example. It is preferable that the conductive substrate of this embodiment does not discolor due to appearance concerns.

[0047] <Crack Resistance> In some embodiments of the present invention, where the conductive substrate according to the present invention is applied to an electropenetrating adhesive sheet described later, it is preferable that the amount of crack formation in the conductive layer of the conductive substrate is suppressed even when the electropenetrating adhesive sheet is stretched or bent. That is, in some embodiments where the crack resistance of the conductive layer is important, it is preferable that the change in the sheet resistance value is low. Specifically, when the conductive substrate of this embodiment is stretched or bent, it is required that a predetermined voltage can be applied to the electropenetrating adhesive layer when applied to an electropenetrating adhesive sheet, and that good electropenetration properties can be exhibited. In some embodiments of the present invention where the crack resistance of the conductive layer is important, it has been found that there is a correlation between the crack resistance of the conductive layer and the sheet resistance value when stretched by 5% in the planar direction, and that a suitable conductive substrate can be selected using the sheet resistance value after stretching.

[0048] In some embodiments where crack resistance of the conductive layer is important, the conductive substrate of this embodiment has a sheet resistance value of 5 kΩ / □ or less when stretched 5% in the planar direction, more preferably 2 kΩ / □ or less, even more preferably 1.5 kΩ / □ or less, even more preferably 1.2 kΩ / □ or less, even more preferably 1.0 kΩ / □ or less, and particularly preferably 0.5 kΩ / □ or less. The lower limit of the sheet resistance when stretched 5% in the planar direction is not particularly limited. Furthermore, the sheet resistance value when the conductive substrate is stretched 5% in the planar direction can be selected according to the purpose and conditions of use, i.e., the applied voltage conditions for peeling (whether peeling is desired at a high voltage or a low voltage). Lowering the sheet resistance value tends to lower the voltage required for peeling. For example, the sheet resistance value may be 0.4 kΩ / □ or less, 0.3 kΩ / □ or less, 0.2 kΩ / □ or less, 0.16 kΩ / □ or less, 0.12 kΩ / □ or less, 0.10 kΩ / □ or less, 0.09 kΩ / □ or less, 0.085 kΩ / □ or less, 0.08 kΩ / □ or less, 0.050 kΩ / □ or less, or 0.035 kΩ / □ or less.

[0049] <Applications of the conductive substrate> The applications of the conductive substrate of this embodiment are not particularly limited, but it can preferably be used for electrolytic delamination and / or for fixing components in electrical and electronic equipment. Specifically, it can be suitably used as a conductive substrate constituting the adhesive sheet in the "Applications of adhesive sheets" described later. That is, the conductive substrate of this embodiment can be used as a substrate for adhesive sheets used to fix components in electrical and electronic equipment.

[0050] <Method for Manufacturing a Conductive Substrate> The method for manufacturing the conductive substrate of this embodiment is not particularly limited, and it is sufficient to form a conductive layer on the surface of the substrate. For example, a conductive layer may be formed on the surface of the substrate as exemplified above by a plating method, chemical vapor deposition method, sputtering method, etc. If the conductive layer has an underlayer in addition to the metal layer, the underlayer may be formed on the surface of the substrate by the above method, and then the metal layer may be further formed by the above method.

[0051] [Adhesive Sheet] The adhesive sheet of this embodiment includes the conductive substrate of this embodiment described above and an adhesive layer.

[0052] The adhesive sheet of this embodiment is not particularly limited as long as it comprises the conductive substrate of this embodiment described above and an adhesive layer (which may be an "electro-peelable adhesive layer" whose adhesive strength decreases when a voltage is applied, or an "other adhesive layer" other than an electro-peelable adhesive layer). The adhesive sheet of this embodiment may be, for example, in the form of a roll or in the form of a sheet. Note that "adhesive sheet" also means "adhesive tape". That is, the adhesive sheet of this embodiment may be an adhesive tape having a tape-like form.

[0053] The adhesive sheet of this embodiment may be a double-sided adhesive sheet having a conductive substrate of this embodiment, wherein both sides of the substrate are covered with an adhesive layer (an electrorelease adhesive layer, or another adhesive layer). Alternatively, the adhesive sheet of this embodiment may be a single-sided adhesive sheet having a conductive substrate of this embodiment, wherein only one side of the substrate is covered with an adhesive layer (an electrorelease adhesive layer, or another adhesive layer). The adhesive sheet of this embodiment may have a release liner for the purpose of protecting the surface of the adhesive layer, but such release liner is not included in the adhesive sheet of this embodiment.

[0054] The adhesive sheet of this embodiment comprises a conductive substrate of this embodiment and an electrorelease adhesive layer whose adhesive strength decreases when a voltage is applied, wherein the conductive layer-side surface of the conductive substrate and the electrorelease adhesive layer are in contact. Alternatively, the adhesive sheet of this embodiment may also comprise a conductive substrate of this embodiment and an electrorelease adhesive layer whose adhesive strength decreases when a voltage is applied, wherein the conductive substrate further comprises an easy-adhesion layer on the conductive layer-side surface, and the easy-adhesion layer and the electrorelease adhesive layer are in contact.

[0055] Furthermore, it is preferable that the adhesive sheet of this embodiment further comprises another adhesive layer, wherein the other adhesive layer is formed on the surface of the conductive substrate opposite to the electropenetrating adhesive layer.

[0056] Furthermore, the adhesive sheet of this embodiment further comprises another adhesive layer, a second conductive substrate, and a second other adhesive layer, wherein the other adhesive layer is formed on the surface of the conductive substrate opposite to the electropenetrating adhesive layer, and the second conductive substrate and the second other adhesive layer are formed in this order on the surface of the electropenetrating adhesive layer opposite to the conductive substrate, and the conductive surface of the second conductive substrate is in contact with the electropenetrating adhesive layer, making it preferably an electropenetrating adhesive sheet. The second conductive substrate may be the conductive substrate of this embodiment or not. Also, in the second conductive substrate, the substrate is not essential, and it may consist only of a conductive layer.

[0057] The structure of the adhesive sheet in this embodiment is not particularly limited, but adhesive sheet X1, which shows a laminated structure in Figure 3, and adhesive sheet X2, which shows a laminated structure in Figure 4, are preferred. Adhesive sheet X1 is a double-sided adhesive sheet with a substrate having a layer structure of other adhesive layer 2, conductive substrate 5 (substrate 3 and conductive layer 4 (metal layer 6)), and electrorelease adhesive layer 1. Adhesive sheet X2 is a double-sided adhesive sheet with a substrate having a layer structure of other adhesive layer 2, conductive substrate 5 (substrate 3 and conductive layer 4 (metal layer 6)), electrorelease adhesive layer 1, conductive substrate 5 (substrate 3 and conductive layer 4 (metal layer 6)), and other adhesive layer 2. In adhesive sheet X1 of Figure 3, it may also be a single-sided adhesive sheet without the other adhesive layer 2.

[0058] The electropenetrating adhesive layer 1 is an adhesive layer that has the property of decreasing adhesive strength when a voltage is applied. The electropenetrating adhesive layer contains a polymer that acts as an adhesive and an electrolyte that is an ionic substance containing electrically charged molecules (ions). Ionic substances are a general term for substances composed of at least one pair of anions and cations. Regardless of their form, they refer to substances that ionize in a polymer, in a solution, in a liquid state, or in a solid state and exhibit electrical conductivity. At room temperature (25°C), ionic substances can be in any state other than gas. That is, at room temperature (25°C), ionic substances may be solid, liquid, or in an intermediate state between solid and liquid (e.g., liquid crystal, flexible crystal, viscous solid, viscous liquid). The state in which an ionic substance is at room temperature (25°C) depends on its molecular structure. For example, ionic liquids are compounds composed of cations and anions, having a melting point below room temperature (25°C) and exhibiting liquid properties at room temperature, such as 1-ethyl-3-methylimidazolium bis(fluorosulfonyl)imide. Ionic solids are substances with a melting point higher than 25°C and possessing ionic properties, such as metal salts (e.g., sodium chloride and copper sulfate) and high-melting-point organic ionic solids (e.g., 1-ethyl-3-methylimidazolium bromide, 1-ethyl-1-methylpiperidinium iodide). The electropenetrating adhesive layer 1 can be formed from an adhesive composition containing a polymer and an electrolyte. The adhesive composition for forming the electropenetrating adhesive layer (hereinafter also referred to as the adhesive composition of this embodiment) will be described below. In this specification, the adhesive strength when no voltage is applied is sometimes referred to as "initial adhesive strength." The property of the adhesive strength decreasing when voltage is applied is called "electropenetration," and a large decrease in adhesive strength due to voltage application is sometimes referred to as "excellent electropenetration."

[0059] <Components of the Adhesive Composition> (Polymer) The adhesive composition of this embodiment contains a polymer. In this embodiment, the polymer is not particularly limited as long as it is a general organic polymer compound, for example, a monomer polymer or partial polymer. The monomer may be a single monomer or a mixture of two or more monomers. A partial polymer means a polymer in which at least a part of the monomer or monomer mixture is partially polymerized.

[0060] The polymer in this embodiment is not particularly limited as long as it is commonly used as an adhesive and has adhesive properties, but examples include acrylic polymers, rubber polymers, vinyl alkyl ether polymers, silicone polymers, polyester polymers, polyamide polymers, urethane polymers, fluoropolymers, and epoxy polymers. The polymer can be used alone or in combination of two or more. In order to increase the dielectric constant of the components other than the ionic liquid in the resulting electropeelable adhesive layer and improve electropeelability, it is preferable that the polymer has a high dielectric constant. From this viewpoint, it is particularly preferable that the polymer in this embodiment includes at least one selected from the group consisting of polyester polymers and acrylic polymers having carboxyl groups and / or hydroxyl groups. Since polyester polymers have hydroxyl groups at their ends that are easily polarized, and since the carboxyl groups and / or hydroxyl groups in acrylic polymers have hydroxyl groups that are easily polarized, it is possible to obtain a polymer with a relatively high dielectric constant by using these polymers. In this embodiment, the total content of polyester polymers and acrylic polymers having carboxyl groups and / or hydroxyl groups in the polymer is preferably 60% by mass or more, and more preferably 80% by mass or more. In particular, in order to increase cost, productivity, and initial adhesive strength, the polymer in this embodiment is preferably an acrylic polymer. That is, the adhesive composition of this embodiment is preferably an acrylic adhesive composition containing an acrylic polymer as the polymer.

[0061] The acrylic polymer preferably contains monomer units derived from alkyl (meth)acrylate esters having C1 to C14 alkyl groups (formula (1) below). Such monomer units are suitable for obtaining high initial adhesion. Furthermore, to increase the dielectric constant of components other than the ionic liquid in the electropenetrating adhesive layer and improve electropenetration, the alkyl group R in formula (1) below is used. ｂ The number of carbon atoms is preferably small, particularly preferably 8 or less, and more preferably 4 or less. ２ = C(R ａ ) COOR ｂ (1) [R in equation (1) ａ R is a hydrogen atom or a methyl group, ｂ [This is an alkyl group having 1 to 14 carbon atoms, which may have substituents.]

[0062] Examples of alkyl (meth)acrylate esters having an alkyl group with 1 to 14 carbon atoms 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, and 2-ethylbutyl (meth)acrylate. Examples include 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, n-tetradecyl(meth)acrylate, and 2-methoxyethyl acrylate. Among these, n-butyl acrylate, 2-ethylhexyl acrylate, isononyl acrylate, and 2-methoxyethyl acrylate are preferred. Alkyl (meth)acrylate esters having an alkyl group with 1 to 14 carbon atoms can be used alone or in combination of two or more.

[0063] The proportion of alkyl (meth)acrylate ester having an alkyl group with 1 to 14 carbon atoms relative to the total monomer components (100% by mass) constituting the acrylic polymer is not particularly limited, but is preferably 70% by mass or more, more preferably 80% by mass or more, and even more preferably 85% by mass or more. When the proportion of alkyl (meth)acrylate ester having an alkyl group with 1 to 14 carbon atoms is 70% by mass or more, it becomes easier to obtain a large initial adhesive strength.

[0064] As an acrylic polymer, it is preferable to include monomer units derived from alkyl (meth)acrylate esters having alkyl groups with 1 to 14 carbon atoms, as well as monomer units derived from polar group-containing monomers copolymerizable thereto, for the purpose of modifying cohesive strength, heat resistance, crosslinkability, etc. The monomer units can provide crosslinking sites and are suitable for obtaining high initial adhesion. Furthermore, it is preferable to include monomer units derived from polar group-containing monomers from the viewpoint of increasing the dielectric constant of components other than the ionic liquid in the electropenetrating adhesive layer and improving electropenetration.

[0065] Examples of polar group-containing monomers include carboxyl group-containing monomers, hydroxyl group-containing monomers, cyano group-containing monomers, vinyl group-containing monomers, aromatic vinyl monomers, amide group-containing monomers, imide group-containing monomers, amino group-containing monomers, epoxy group-containing monomers, vinyl ether monomers, N-acryloylmorpholine, sulfo group-containing monomers, phosphate group-containing monomers, and acid anhydride group-containing monomers. Among these, carboxyl group-containing monomers, hydroxyl group-containing monomers, and amide group-containing monomers are preferred due to their excellent cohesiveness, and carboxyl group-containing monomers are particularly preferred. Carboxyl group-containing monomers are especially suitable for obtaining high initial adhesion. Polar group-containing monomers can be used alone or in combination of two or more types.

[0066] Examples of carboxyl group-containing monomers include acrylic acid, methacrylic acid, carboxyethyl (meth)acrylate, carboxypentyl (meth)acrylate, itaconic acid, maleic acid, fumaric acid, crotonic acid, and isocrotonic acid. Acrylic acid is particularly preferred. Carboxyl group-containing monomers can be used alone or in combination of two or more.

[0067] 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 (meth)acrylate, N-methylol (meth)acrylamide, vinyl alcohol, allyl alcohol, 2-hydroxyethyl vinyl ether, 4-hydroxybutyl vinyl ether, and diethylene glycol monovinyl ether. In particular, 2-hydroxyethyl (meth)acrylate and 4-hydroxybutyl (meth)acrylate are preferred. Hydroxyl group-containing monomers can be used alone or in combination of two or more.

[0068] Examples of amide group-containing monomers include acrylamide, methacrylamide, N-vinylpyrrolidone, N,N-dimethylacrylamide, N,N-dimethylmethacrylamide, N,N-diethylacrylamide, N,N-diethylmethacrylamide, N,N'-methylenebisacrylamide, N,N-dimethylaminopropylacrylamide, N,N-dimethylaminopropylmethacrylamide, and diacetoneacrylamide. Amide group-containing monomers can be used alone or in combination of two or more.

[0069] Examples of cyano group-containing monomers include acrylonitrile and methacrylonitrile.

[0070] Examples of vinyl group-containing monomers include vinyl acetate, vinyl propionate, and vinyl esters such as vinyl laurate, with vinyl acetate being particularly preferred.

[0071] Examples of aromatic vinyl monomers include styrene, chlorostyrene, chloromethylstyrene, α-methylstyrene, and other substituted styrenes.

[0072] Examples of imide group-containing monomers include cyclohexylmaleimide, isopropylmaleimide, N-cyclohexylmaleimide, and itaconimide.

[0073] Examples of amino group-containing monomers include aminoethyl (meth)acrylate, N,N-dimethylaminoethyl (meth)acrylate, and N,N-dimethylaminopropyl (meth)acrylate.

[0074] Examples of epoxy group-containing monomers include glycidyl (meth)acrylate, methylglycidyl (meth)acrylate, and allyl glycidyl ether.

[0075] Examples of vinyl ether monomers include methyl vinyl ether, ethyl vinyl ether, and isobutyl vinyl ether.

[0076] The proportion of polar group-containing monomers to the total monomer components (100% by mass) constituting the acrylic polymer is preferably 0.1% by mass or more and 35% by mass or less. The upper limit of the proportion of polar group-containing monomers is more preferably 25% by mass, even more preferably 20% by mass, the lower limit is more preferably 0.5% by mass, even more preferably 1% by mass, and particularly preferably 2% by mass. When the proportion of polar group-containing monomers is 0.1% by mass or more, cohesive force is easily obtained, so adhesive residue is less likely to occur on the surface of the adherend after peeling off the electrorelease adhesive layer, and electrorelease properties are improved. Furthermore, when the proportion of polar group-containing monomers is 35% by mass or less, it becomes easier to prevent the electrorelease adhesive layer from adhering excessively to the adherend and causing excessive peeling. In particular, when it is 2% by mass or more and 20% by mass or less, it becomes easier to achieve both peelability to the adherend and adhesion between the electrorelease adhesive layer and other layers.

[0077] Furthermore, the monomer components constituting the acrylic polymer may include polyfunctional monomers in order to introduce a cross-linked structure into the acrylic polymer and facilitate obtaining the necessary cohesive force.

[0078] Examples of polyfunctional monomers include ethylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, tetraethylene glycol di(meth)acrylate, neopentyl glycol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, dipentaerythritol hexa(meth)acrylate, divinylbenzene, and N,N'-methylenebisacrylamide. Polyfunctional monomers can be used individually or in combination of two or more.

[0079] The content of polyfunctional monomers relative to the total monomer components (100% by mass) constituting the acrylic polymer is preferably 0.1% by mass or more and 15% by mass or less. The upper limit of the polyfunctional monomer content is more preferably 10% by mass, and the lower limit is more preferably 3% by mass. A polyfunctional monomer content of 0.1% by mass or more is preferable because it tends to improve the flexibility and adhesion of the electro-peelable adhesive layer. A polyfunctional monomer content of 15% by mass or less makes it easier to obtain appropriate adhesion without the cohesive force becoming too high.

[0080] Polyester polymers are typically polymers having a structure in which polycarboxylic acids such as dicarboxylic acids or their derivatives (hereinafter also referred to as "polycarboxylic acid monomers") and polyhydric alcohols such as diols or their derivatives (hereinafter referred to as "polyhydric alcohol monomers") are condensed together.

[0081] The polycarboxylic acid monomers are not particularly limited, but examples include adipic acid, azelaic acid, dimer acid, sebacic acid, 1,4-cyclohexanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid, 1,2-cyclohexanedicarboxylic acid, 4-methyl-1,2-cyclohexanedicarboxylic acid, dodecenyl succinic anhydride, fumaric acid, succinic acid, dodecanediic acid, hexahydrophthalic anhydride, tetrahydrophthalic anhydride, maleic acid, maleic anhydride, itaconic acid, citraconic acid, and derivatives thereof. The polycarboxylic acid monomers can be used alone or in combination of two or more.

[0082] The polyhydric alcohol monomer is not particularly limited, but examples include ethylene glycol, 1,2-propylene glycol, 1,3-propanediol, 2-methyl-1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 3-methyl-1,5-pentanediol, neopentyl glycol, diethylene glycol, dipropylene glycol, 2,2,4-trimethyl-1,5-pentanediol, 2-ethyl-2-butylpropanediol, 1,9-nonanediol, 2-methyloctanediol, 1,10-decanediol, and derivatives thereof. The polyhydric alcohol monomer can be used alone or in combination of two or more.

[0083] Furthermore, the polymer of this embodiment may also contain an ionic polymer. An ionic polymer is a polymer having ionic functional groups. By including an ionic polymer in the polymer, the dielectric constant of the polymer increases, and the electrolytic properties are improved. When the polymer contains an ionic polymer, the content of the ionic polymer is preferably 0.05 parts by mass or more and 2 parts by mass or less per 100 parts by mass of the polymer.

[0084] In this embodiment, the polymer can be obtained by (co)polymerizing monomer components. The polymerization method is not particularly limited, but examples include solution polymerization, emulsion polymerization, bulk polymerization, suspension polymerization, and photopolymerization (active energy ray polymerization). Solution polymerization is particularly preferred from the viewpoint of cost and productivity. When copolymerized, the polymer may be a random copolymer, block copolymer, alternating copolymer, graft copolymer, etc.

[0085] Solution polymerization methods are not particularly limited, but include methods in which monomer components, polymerization initiators, etc., are dissolved in a solvent, heated to polymerize, and a polymer solution containing the polymer is obtained.

[0086] Various common solvents can be used as solvents in solution polymerization. Examples of such solvents (polymerization solvents) include aromatic hydrocarbons such as toluene, benzene, and xylene; esters such as ethyl acetate and n-butyl acetate; aliphatic hydrocarbons such as n-hexane and n-heptane; alicyclic hydrocarbons such as cyclohexane and methylcyclohexane; and organic solvents such as ketones such as methyl ethyl ketone and methyl isobutyl ketone. Solvents can be used individually or in combination of two or more.

[0087] The amount of solvent used is not particularly limited, but is preferably 10 parts by mass or more and 1000 parts by mass or less relative to the total monomer components constituting the polymer (100 parts by mass). The upper limit of the amount of solvent used is more preferably 500 parts by mass, and the lower limit is more preferably 50 parts by mass.

[0088] Polymerization initiators used in solution polymerization are not particularly limited, but include peroxide-based polymerization initiators and azo-based polymerization initiators. Peroxide-based polymerization initiators are not particularly limited, but include peroxycarbonates, ketone peroxides, peroxyketals, hydroperoxides, dialkyl peroxides, diacyl peroxides, and peroxyesters. More specifically, examples include benzoyl peroxide, t-butyl hydroperoxide, di-t-butyl peroxide, t-butyl peroxybenzoate, dicumyl peroxide, 1,1-bis(t-butylperoxy)-3,3,5-trimethylcyclohexane, and 1,1-bis(t-butylperoxy)cyclododecane. The azo polymerization initiators are not particularly limited, but include 2,2'-azobisisobutyronitrile, 2,2'-azobis-2-methylbutyronitrile, 2,2'-azobis(2,4-dimethylvaleronitrile), 2,2'-azobis(2-methylpropionic acid)dimethyl, 2,2'-azobis(4-methoxy-2,4-dimethylvaleronitrile), 1,1'-azobis(cyclohexane-1-carbonitride), 2,2'-azobis(2,4,4-trimethylpentane), and 4,4'-azobis Examples include -4-cyanovaleric acid, 2,2'-azobis(2-amidinopropane)dihydrochloride, 2,2'-azobis[2-(5-methyl-2-imidazolin-2-yl)propane]dihydrochloride, 2,2'-azobis(2-methylpropionamidine)disulfate, 2,2'-azobis(N,N'-dimethyleneisobutylamidine)hydrochloride, and 2,2'-azobis[N-(2-carboxyethyl)-2-methylpropionamidine]hydrate. Polymerization initiators can be used alone or in combination of two or more.

[0089] The amount of polymerization initiator used is not particularly limited, but is preferably 0.01 parts by mass or more and 5 parts by mass or less relative to the total monomer components constituting the polymer (100 parts by mass). The upper limit of the amount of polymerization initiator used is more preferably 3 parts by mass, and the lower limit is more preferably 0.05 parts by mass.

[0090] In solution polymerization, the heating temperature during polymerization is not particularly limited, but is, for example, 50°C to 80°C. The heating time is not particularly limited, but is, for example, 1 hour to 24 hours.

[0091] The weight-average molecular weight of the polymer is not particularly limited, but is preferably between 100,000 and 5,000,000. The upper limit of the weight-average molecular weight is more preferably 4,000,000, even more preferably 3,000,000, and the lower limit is more preferably 200,000, even more preferably 300,000. When the weight-average molecular weight is 100,000 or more, the cohesive force is reduced, which effectively suppresses the problem of adhesive residue remaining on the surface of the adherend after the electro-peelable adhesive layer has been removed. Furthermore, when the weight-average molecular weight is 5,000,000 or less, it effectively suppresses the problem of insufficient wettability on the surface of the adherend after the electro-peelable adhesive layer has been removed.

[0092] The weight-average molecular weight was obtained by measuring using gel permeation chromatography (GPC). More specifically, for example, using a GPC measuring device such as the "HLC-8220GPC" (manufactured by Tosoh Corporation), the measurement was performed under the following conditions, and the value was calculated using the standard polystyrene equivalent. (Weight-average molecular weight measurement conditions) ・Sample concentration: 0.2% by mass (tetrahydrofuran solution) ・Sample injection volume: 10 μL ・Sample column: TSKguardcolumn SuperHZ-H (1 tube) + TSKgel SuperHZM-H (2 tubes) ・Reference column: TSKgel SuperH-RC (1 tube) ・Eluent: Tetrahydrofuran (THF) ・Flow rate: 0.6 mL / min ・Detector: Differential refractometer (RI) ・Column temperature (measurement temperature): 40°C

[0093] The glass transition temperature (Tg) of the polymer is not particularly limited, but it is preferably 0°C or lower because it suppresses the decrease in initial adhesive strength, more preferably -10°C or lower, and even more preferably -20°C or lower. Furthermore, it is particularly preferable to have a temperature of -40°C or lower because the rate of decrease in adhesive strength due to voltage application is particularly large, and most preferably -50°C or lower.

[0094] The glass transition temperature (Tg) can be calculated, for example, based on the following equation (Y) (Fox equation): 1 / Tg = W1 / Tg1 + W2 / Tg2 + ... + Wn / Tgn (Y) [In equation (Y), Tg is the glass transition temperature of the polymer (unit: K), Tgi (i = 1, 2, ..., n) is the glass transition temperature when monomer i forms a homopolymer (unit: K), and Wi (i = 1, 2, ..., n) represents the mass fraction of monomer i in the total monomer components]. The above equation (Y) is the calculation formula when the polymer is composed of n types of monomer components: monomer 1, monomer 2, ..., monomer n.

[0095] The glass transition temperature when forming a homopolymer refers to the glass transition temperature of the homopolymer of the monomer in question, and specifically refers to the glass transition temperature (Tg) of a polymer formed using only one monomer (sometimes referred to as "monomer X") as the monomer component. The specific values ​​are given in "Polymer Handbook" (3rd edition, John Wiley & Sons, Inc., 1989). Note that the glass transition temperature (Tg) of a homopolymer not listed in the aforementioned literature refers to a value obtained, for example, by the following measurement method: In a reactor equipped with a thermometer, stirrer, nitrogen inlet tube, and reflux condenser, 100 parts by mass of monomer X, 0.2 parts by mass of 2,2'-azobisisobutyronitrile, and 200 parts by mass of ethyl acetate as the polymerization solvent are added, and the mixture is stirred for 1 hour while introducing nitrogen gas. After removing oxygen from the polymerization system in this way, the temperature is raised to 63°C and the reaction is carried out for 10 hours. Then, the mixture is cooled to room temperature to obtain a homopolymer solution with a solid content of 33% by mass. Next, this homopolymer solution is cast onto a release liner and dried to produce a test sample (sheet-like homopolymer) with a thickness of approximately 2 mm. Then, approximately 1-2 mg of this test sample is weighed into an aluminum open cell, and the reversing heat flow (specific heat component) behavior of the homopolymer is obtained using a temperature-modulated DSC (product name "Q-2000," manufactured by T.A. Instruments Corporation) at a heating rate of 5°C / min under a nitrogen atmosphere of 50 ml / min. Referring to JIS-K-7121, the glass transition temperature (Tg) of the homopolymer is defined as the temperature at the point where a line equidistant in the vertical axis direction from the line extending from the low-temperature baseline and the high-temperature baseline of the obtained reversing heat flow intersects with the curve of the step-like change portion of the glass transition.

[0096] The polymer content in the adhesive composition of this embodiment is preferably 50% by mass or more and 99.9% by mass or less, based on the total amount of the adhesive composition (100% by mass), with the upper limit being more preferably 99.5% by mass, even more preferably 99% by mass, and the lower limit being more preferably 60% by mass, even more preferably 70% by mass.

[0097] (Ionic Substance) The adhesive composition according to the embodiment of the present invention contains an electrolyte. Furthermore, the adhesive composition according to the embodiment of the present invention may be an electropenetrating adhesive composition, and the ionic substance that is the electrolyte may be an ionic liquid. From the viewpoint of achieving good electropenetration in the electropenetrating adhesive layer, an ionic liquid is preferred as the electrolyte contained in the electropenetrating adhesive layer.

[0098] Anions in ionic substances are, for example, (FSO ２ ) ２ N － (CF ３ SO ２ ) ２ N － (CF ３ CF ２ SO ２ ) ２ N － (CF ３ SO ２ ) ３ C － , B(CN) ４ － , C (CN) ３ － , N (CN) ２ － , 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 － These are some examples. Among them, as anions, (FSO ２ ) ２ N － [Bis(fluorosulfonyl)imide anion] and (CF ３ SO ２ ) ２ N － Anions of sulfonylime compounds, such as [bis(trifluoromethanesulfonyl)imide anion], are commonly used because they are chemically stable and suitable for improving electrolysis. In other words, the anion of the ionic substance is generally selected from the group consisting of bis(fluorosulfonyl)imide anion and bis(trifluoromethanesulfonyl)imide anion.

[0099] In ionic materials, cations are generally selected from the group consisting of nitrogen-containing onium cations, sulfur-containing onium cations, and phosphorus-containing onium cations because they are chemically stable and suitable for improving electrolysis. Imidazolium-based, ammonium-based, pyrrolidinium-based, and pyridinium-based cations are more commonly used.

[0100] Examples of imidazolium-based cations include 1-methylimidazolium cation, 1-ethyl-3-methylimidazolium cation, 1-propyl-3-methylimidazolium cation, 1-butyl-3-methylimidazolium cation, 1-pentyl-3-methylimidazolium cation, 1-hexyl-3-methylimidazolium cation, 1-heptyl-3-methylimidazolium cation, 1-octyl-3-methylimidazolium cation, 1-nonyl-3-methylimidazolium cation, 1-undecyl-3-methylimidazolium cation, and 1-dodecyl-3-methylimidazolium cation. Examples include 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.

[0101] 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.

[0102] Examples of pyrrolidinium-based cations include 1-ethyl-1-methylpyrrolidinium cation and 1-butyl-1-methylpyrrolidinium cation.

[0103] Examples of ammonium-based cations include tetraethylammonium cation, tetrabutylammonium cation, methyltrioctylammonium cation, tetradecyltrihexylammonium cation, glycidyltrimethylammonium cation, and trimethylaminoethyl acrylate cation.

[0104] As the ionic substance, from the viewpoint of increasing the reduction rate of the adhesive force when a voltage is applied, it is preferable to select a cation having a molecular weight of 160 or less as the cation constituting the ionic substance. The above (FSO ２ ) ２ N － [bis(fluorosulfonyl)imide anion] or (CF ３ SO ２ ) ２ N － [bis(trifluoromethanesulfonyl)imide anion] and an ionic liquid containing a cation having a molecular weight of 160 or less are 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, trimethylaminoethyl acrylate cation, and the like.

[0105] Further, as the cation of the ionic liquid, cations represented by the following formulas (2-A) to (2-D) are also preferable.

[0106] [[ID=2L]]

[0107] In formula (2-A), R １ represents a hydrocarbon group having 4 to 10 carbon atoms (preferably a hydrocarbon group having 4 to 8 carbon atoms, more preferably a hydrocarbon group having 4 to 6 carbon atoms), and may contain a heteroatom. R ２ and R ３ are the same or different and represent a hydrogen atom or a hydrocarbon group having 1 to 12 carbon atoms (preferably a hydrocarbon group having 1 to 8 carbon atoms, more preferably a hydrocarbon group having 2 to 6 carbon atoms, still more preferably a hydrocarbon group having 2 to 4 carbon atoms), and may contain a heteroatom. However, when a nitrogen atom forms a double bond with an adjacent carbon atom, R３ does not exist.

[0108] R in formula (2-B) ４ represents a hydrocarbon group having 2 to 10 carbon atoms (preferably a hydrocarbon group having 2 to 8 carbon atoms, more preferably a hydrocarbon group having 2 to 6 carbon atoms), and may contain a heteroatom. R ５ , R ６ , and R ７ are the same or different and represent a hydrogen atom or a hydrocarbon group having 1 to 12 carbon atoms (preferably a hydrocarbon group having 1 to 8 carbon atoms, more preferably a hydrocarbon group having 2 to 6 carbon atoms, still more preferably a hydrocarbon group having 2 to 4 carbon atoms), and may contain a heteroatom.

[0109] R in formula (2-C) ８ represents a hydrocarbon group having 2 to 10 carbon atoms (preferably a hydrocarbon group having 2 to 8 carbon atoms, more preferably a hydrocarbon group having 2 to 6 carbon atoms), and may contain a heteroatom. R ９ , R １０ , and R １１ are the same or different and represent a hydrogen atom or a hydrocarbon group having 1 to 16 carbon atoms (preferably a hydrocarbon group having 1 to 10 carbon atoms, more preferably a hydrocarbon group having 1 to 8 carbon atoms), and may contain a heteroatom.

[0110] X in formula (2-D) represents a nitrogen, sulfur, or phosphorus atom. R １２ , R １３ , R １４ , and R １５ are the same or different and represent a hydrocarbon group having 1 to 16 carbon atoms (preferably a hydrocarbon group having 1 to 14 carbon atoms, more preferably a hydrocarbon group having 1 to 10 carbon atoms, still more preferably a hydrocarbon group having 1 to 8 carbon atoms, particularly preferably a hydrocarbon group having 1 to 6 carbon atoms), and may contain a heteroatom. However, when X is a sulfur atom, R １２ does not exist.

[0111] The molecular weight of cations in ionic materials is, for example, 500 or less, preferably 400 or less, more preferably 300 or less, even more preferably 250 or less, particularly preferably 200 or less, and most preferably 160 or less. It is also usually 50 or more. It is believed that cations in ionic materials have the property of moving towards the cathode side in the adhesive layer when a voltage is applied, and becoming concentrated near the interface between the adhesive layer and the adherend. In this invention, for this reason, the adhesive strength decreases with voltage application compared to the initial adhesive strength, resulting in electrolysis. Cationic materials with a small molecular weight, such as 500 or less, are preferable because the movement of cations towards the cathode side in the adhesive layer is easier, and this increases the rate of decrease in adhesive strength when a voltage is applied.

[0112] Examples of commercially available ionic substances include "Elexel AS-110," "Elexel MP-442," "Elexel IL-210," "Elexel MP-471," "Elexel MP-456," and "Elexel AS-804" from Daiichi Kogyo Seiyaku Co., Ltd., "HMI-FSI" from Mitsubishi Materials Corporation, and "CIL-312" and "CIL-313" from Nippon Carlit Co., Ltd.

[0113] The ionic conductivity of the ionic material is preferably between 0.1 mS / cm and 10 mS / cm. The upper limit of the ionic conductivity is more preferably 5 mS / cm, even more preferably 3 mS / cm, and the lower limit is more preferably 0.3 mS / cm, even more preferably 0.5 mS / cm. Having an ionic conductivity within this range ensures that the adhesive strength is sufficiently reduced even at low voltages. The ionic conductivity can be measured, for example, by the AC impedance method using a Solartron 1260 frequency response analyzer.

[0114] While there are no particular restrictions on the content (amount blended) of an ionic substance, preferably an ionic liquid, in the adhesive composition of this embodiment, it is preferable that the content of the ionic substance per 100 parts by mass of polymer is 0.5 parts by mass or more and 30 parts by mass or less. From the viewpoint of reducing the adhesive strength when voltage is applied, the content of the ionic substance per 100 parts by mass of polymer is preferably 0.5 parts by mass or more, and from the viewpoint of increasing the initial adhesive strength, it is preferable that the content of the ionic substance is 30 parts by mass or less. From the same viewpoint, it is more preferable that it is 20 parts by mass or less, even more preferable that it is 15 parts by mass or less, particularly preferable that it is 10 parts by mass or less, and most preferable that it is 5 parts by mass or less. Furthermore, it is more preferable that it is 0.6 parts by mass or more, even more preferable that it is 0.8 parts by mass or more, particularly preferable that it is 1.0 part by mass or more, and most preferable that it is 1.5 parts by mass or more.

[0115] (Other Components) The adhesive composition of this embodiment may contain one or more components other than polymers and ionic liquids (hereinafter sometimes referred to as "other components"), as necessary, to the extent that they do not impair the effects of the present invention. The other components that may be contained in the adhesive composition of this embodiment are described below.

[0116] The adhesive composition of this embodiment may contain an ionic additive for the purpose of controlling ionic conductivity. As the ionic additive, for example, an ionic solid can be used.

[0117] An ionic solid is an ionic substance that is solid at 25°C. The ionic solid is not particularly limited, but for example, a solid ionic substance obtained by combining anions and cations as exemplified in the section describing ionic liquids above can be used. When the adhesive composition contains an ionic solid, the content of the ionic solid is preferably 0.5 parts by mass or more, more preferably 1 part by mass or more, preferably 10 parts by mass or less, more preferably 5 parts by mass or less, and even more preferably 2.5 parts by mass or less, per 100 parts by mass of polymer.

[0118] The adhesive composition of this embodiment may optionally contain a crosslinking agent for the purpose of improving creep and shear properties by crosslinking the polymer. Examples of crosslinking agents include isocyanate-based crosslinking agents, epoxy-based crosslinking agents, melamine-based crosslinking agents, peroxide-based crosslinking agents, urea-based crosslinking agents, metal alkoxide-based crosslinking agents, metal chelate-based crosslinking agents, metal salt-based crosslinking agents, oxazoline-based crosslinking agents, aziridine-based crosslinking agents, and amine-based crosslinking agents. Examples of isocyanate-based crosslinking agents include toluene diisocyanate and methylene bisphenyl isocyanate. Commercially available isocyanate-based crosslinking agents include "Duranate TPA-100," "Duranate D101," and "Duranate D201" from Asahi Kasei Chemicals Corporation, "Coronate HL," "Coronate HK," "Coronate HX," and "Coronate 2096" from Tosoh Corporation, and "Takenate D-101E," "Takenate D-127N," and "Takenate D-131N" from Mitsui Chemicals, Inc.

[0119] Examples of epoxy crosslinking agents include N,N,N',N'-tetraglycidyl-m-xylenediamine, diglycidylaniline, 1,3-bis(N,N-diglycidylaminomethyl)cyclohexane, and 1,6-hexanediol diglycidyl ether. A commercially available epoxy crosslinking agent is the product "TETRAD-C" manufactured by Mitsubishi Gas Chemical Company, Inc.

[0120] When a crosslinking agent is included, its content is preferably 0.001 parts by mass or more, more preferably 0.05 parts by mass or more, and even more preferably 0.01 parts by mass or more, per 100 parts by mass of polymer. For example, the content of the crosslinking agent can be 0.1 parts by mass or more, or 1.0 part by mass or more. Furthermore, the upper limit of the crosslinking agent content is preferably 50 parts by mass or less, more preferably 10 parts by mass or less, and even more preferably 3 parts by mass or less, per 100 parts by mass of polymer. The crosslinking agent can be used alone or in combination of two or more types.

[0121] The adhesive composition of this embodiment may, in addition to the crosslinking agent, optionally contain a crosslinking catalyst for the purpose of more effectively promoting the crosslinking reaction. The crosslinking catalyst is not particularly limited and may include zirconium-containing compounds such as zirconium tetraacetylacetonate, zirconium monoacetylacetonate, zirconium ethylacetoacetate, and zirconium octoate compounds (zirconium-based catalysts); tin (Sn)-containing compounds such as dioctyltin dilaurate, dibutyltin dilaurate, dibutyltin diacetate, dibutyltin diacetylacetonate, tetra-n-butyltin, trimethyltin hydroxide, and butyltin oxide (tin-based catalysts); and aluminum secondary butoxide. Examples of organometallic catalysts include aluminum-containing compounds such as aluminum trisacetylacetonate, aluminum bisethylacetoacetate, and aluminum trisethylacetoacetate (aluminum-based catalysts); iron-containing compounds such as ferric narsem (iron-based catalysts); and titanium-containing compounds such as tetraisopropyl titanate, tetra-n-butyl titanate, butyl titanate dimer, tetraoctyl titanate, titanium acetylacetonate, titanium tetraacetylacetonate, and titanium ethylacetoacetate (titanium-based catalysts). Crosslinking catalysts can be used individually or in combination of two or more.

[0122] While not particularly limited, in this embodiment, it is preferable to use a tin-containing compound with high catalytic activity as the crosslinking catalyst. Alternatively, in other embodiments, a non-tin compound may be used as the crosslinking catalyst from the viewpoint of environmental impact and safety. In such embodiments, the crosslinking catalyst does not need to substantially contain a tin-containing compound. Furthermore, in this embodiment, the crosslinking catalyst does not need to contain an iron-based catalyst. For example, in usage embodiments where transparency and optical properties are required for the adhesive layer, discoloration of the adhesive layer can be prevented or suppressed by avoiding the use of iron-based compounds.

[0123] The amount of crosslinking catalyst used is not particularly limited. The amount of crosslinking catalyst used can be, for example, 0.001 parts by mass or more per 100 parts by mass of polymer, with 0.01 parts by mass or more being appropriate. Alternatively, the amount of crosslinking catalyst used can be, for example, 3 parts by mass or less per 100 parts by mass of polymer, with 1 part by mass or less being appropriate, and it may also be 0.3 parts by mass or less, or even 0.1 parts by mass or less.

[0124] The adhesive composition of this embodiment may optionally contain polyethylene glycol or tetraethylene glycol dimethyl ether to assist in the movement of the ionic liquid when a voltage is applied. Polyethylene glycol or tetraethylene glycol dimethyl ether having a number average molecular weight of 100 to 6000 can be used. When these components are included, the content is preferably 0.1 parts by mass or more, more preferably 0.5 parts by mass or more, even more preferably 1 part by mass or more, and preferably 30 parts by mass or less, more preferably 20 parts by mass or less, and even more preferably 15 parts by mass or less, per 100 parts by mass of polymer.

[0125] The adhesive composition of this embodiment may optionally contain a conductive filler for the purpose of imparting conductivity to the adhesive composition. The conductive filler is not particularly limited, and general known or conventional conductive fillers can be used, such as graphite, carbon black, carbon fiber, or metal powders such as silver or copper. When a conductive filler is included, the content is preferably 0.1 parts by mass or more and 200 parts by mass or less per 100 parts by mass of polymer. In this specification, a component that applies to both filler and conductive filler is referred to as a conductive filler.

[0126] The adhesive composition of this embodiment may optionally contain a corrosion inhibitor to suppress corrosion of the metal adherend. The corrosion inhibitor is not particularly limited, and general known or conventional corrosion inhibitors can be used, such as carbodiimide compounds, adsorption inhibitors, chelate-forming metal deactivators, etc. Examples of carbodiimide compounds include 1-[3-(dimethylamino)propyl]-3-ethylcarbodiimide, 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide, N,N'-dicyclohexylcarbodiimide, N,N'-diisopropylcarbodiimide, 1-ethyl-3-tert-butylcarbodiimide, N-cyclohexyl-N'-(2-morpholinoethyl)carbodiimide, N,N'-di-tert-butylcarbodiimide, 1,3-bis(p-tolyl)carbodiimide, and polycarbodiimide resins using these as monomers. These carbodiimide compounds can be used individually or in combination of two or more. When the adhesive composition of this embodiment contains a carbodiimide compound, the content is preferably 0.01 parts by mass or more and 10 parts by mass or less per 100 parts by mass of polymer.

[0127] Examples of adsorbent inhibitors include alkylamines, carboxylates, carboxylic acid derivatives, and alkyl phosphates. Adsorbent inhibitors can be used alone or in combination of two or more. When the adhesive composition of this embodiment contains alkylamine as an adsorbent inhibitor, the content is preferably 0.01 parts by mass or more and 20 parts by mass or less per 100 parts by mass of polymer. When the adhesive composition of this embodiment contains carboxylates as an adsorbent inhibitor, the content is preferably 0.01 parts by mass or more and 10 parts by mass or less per 100 parts by mass of polymer. When the adhesive composition of this embodiment contains carboxylic acid derivatives as an adsorbent inhibitor, the content is preferably 0.01 parts by mass or more and 10 parts by mass or less per 100 parts by mass of polymer. When the adhesive composition of this embodiment contains alkyl phosphates as an adsorbent inhibitor, the content is preferably 0.01 parts by mass or more and 10 parts by mass or less per 100 parts by mass of polymer.

[0128] As chelate-forming metal deactivators, for example, triazole group-containing compounds or benzotriazole group-containing compounds can be used. These are preferred because they have a high deactivating effect on the surface of metals such as aluminum and do not significantly affect adhesion when included in the adhesive component. Chelate-forming metal deactivators can be used alone or in combination of two or more types. When the adhesive composition of this embodiment contains a chelate-forming metal deactivator, the content is preferably 0.01 parts by mass or more and 20 parts by mass or less per 100 parts by mass of polymer.

[0129] The total content (amount blended) of the corrosion inhibitor is preferably 0.01 parts by mass or more and 30 parts by mass or less per 100 parts by mass of polymer.

[0130] The adhesive composition of this embodiment may also contain various additives such as fillers, plasticizers, antioxidants, antioxidants, pigments (dyes), flame retardants, solvents, surfactants (leveling agents), rust inhibitors, adhesion promoters, tackifying resins, 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 it is preferably 0.01 parts by mass to 20 parts by mass, more preferably 10 parts by mass or less, and even more preferably 5 parts by mass or less, per 100 parts by mass of polymer.

[0131] Examples of fillers include silica, iron oxide, zinc oxide, aluminum oxide, titanium oxide, barium oxide, magnesium oxide, calcium carbonate, magnesium carbonate, zinc carbonate, pyrophyllite clay, kaolin clay, and calcined clay.

[0132] The plasticizer can be a commonly used plasticizer in general resin compositions, such as paraffin oil, process oil, liquid rubber 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 their derivatives, dioctyl phthalate (DOP), dibutyl phthalate (DBP), dioctyl adipate, diisononyl adipate (DINA), and isodecyl succinate.

[0133] Examples of anti-aging agents include hindered phenol compounds, aliphatic and aromatic hindered amine compounds, etc. Examples of antioxidants include butylhydroxytoluene (BHT) and butylhydroxyanisole (BHA), etc. Examples of pigments include inorganic pigments such as titanium dioxide, zinc oxide, ultramarine, red iron oxide, lithopone, lead, cadmium, iron, cobalt, aluminum, hydrochloride salts, sulfates, azo pigments, and organic pigments such as copper phthalocyanine pigments, etc.

[0134] Examples of rust inhibitors include zinc phosphate, tannic acid derivatives, phosphate esters, basic sulfonates, and various rust-preventive pigments. Examples of adhesion promoters include titanium coupling agents and zirconium coupling agents. Examples of antistatic agents include quaternary ammonium salts, or hydrophilic compounds such as polyglycolic acid and ethylene oxide derivatives.

[0135] Examples of tackifying resins include acrylic tackifiers, rosin-based tackifying resins, terpene-based tackifying resins, phenol-based tackifying resins, hydrocarbon-based tackifying resins, ketone-based tackifying resins, as well as polyamide-based tackifying resins, epoxy-based tackifying resins, and elastomer-based tackifying resins. These tackifying resins can be used individually or in combination of two or more types.

[0136] <Adhesive composition, adhesive sheet, and method for manufacturing the same> The adhesive composition of this embodiment is not particularly limited, but can be manufactured by appropriately stirring and mixing a polymer, an ionic liquid, and, if necessary, additives, crosslinking agents, crosslinking catalysts, polyethylene glycol, conductive fillers, etc.

[0137] The adhesive sheet of this embodiment comprises a conductive substrate of this embodiment and an electro-release adhesive layer whose adhesive strength decreases when a voltage is applied, wherein the conductive layer side surface of the conductive substrate and the electro-release adhesive layer are in contact. Adhesive sheet X1, which is one embodiment of the adhesive sheet of this embodiment, is a double-sided adhesive sheet with a substrate having a layer structure of other adhesive layers 2, a conductive substrate 5 (substrate 3 and conductive layer 4 (metal layer 6)), and an electro-release adhesive layer 1. The other adhesive layers 2 are not particularly limited as long as they are adhesive layers other than the electro-release adhesive layer 1, but for example, they can be formed by an adhesive composition that does not contain an ionic liquid in the adhesive composition of this embodiment that forms the electro-release adhesive layer 1 described above.

[0138] When using the adhesive sheet X1 as a joint, it is preferable that the joint be one in which the electro-peelable adhesive layer 1 is attached to a conductive material.

[0139] From the viewpoint of initial adhesive strength, the thickness of the electropenetrating adhesive layer 1 is preferably 1 μm or more and 1000 μm or less. The upper limit of the thickness of the electropenetrating adhesive layer 1 is more preferably 500 μm, even more preferably 300 μm, even more preferably 200 μm, even more preferably 150 μm, even more preferably 100 μm, even more preferably 80 μm, even more preferably 70 μm, even more preferably 60 μm, and even more preferably 50 μm. The lower limit is more preferably 3 μm, even more preferably 5 μm, even more preferably 8 μm, even more preferably 10 μm, even more preferably 20 μm, and even more preferably 30 μm.

[0140] From the viewpoint of adhesive strength, the thickness of the other adhesive layer 2 is preferably 1 μm or more and 2000 μm or less. The upper limit of the thickness of the other adhesive layer 2 is more preferably 1000 μm, even more preferably 500 μm, and particularly preferably 100 μm, and the lower limit is more preferably 3 μm, even more preferably 5 μm, and particularly preferably 8 μm.

[0141] The thicknesses of the base material 3, the conductive layer 4, and the conductive base material 5 can be determined by referring to the explanation in the [Conductive Base Material] section, respectively.

[0142] The surfaces of the electro-peelable adhesive layer and other adhesive layers of the adhesive sheet in this embodiment may be protected by a release liner. The release liner is not particularly limited, but examples include a release liner in which the surface of a substrate (liner substrate) such as paper or plastic film is treated with silicone, and a release liner in which the surface of a substrate (liner substrate) such as paper or plastic film is laminated with a polyolefin resin. The thickness of the release liner is not particularly limited, but is preferably 10 μm or more and 100 μm or less.

[0143] The thickness of the adhesive sheet in this embodiment is preferably 20 μm or more and 3000 μm or less. The upper limit of the thickness is more preferably 1000 μm, even more preferably 300 μm, even more preferably 250 μm, even more preferably 200 μm, even more preferably 150 μm, and even more preferably 100 μm, while the lower limit is more preferably 30 μm and even more preferably 50 μm.

[0144] In particular, in the case of the adhesive sheet X1 shown in Figure 3, the thickness of the adhesive sheet is preferably 50 μm or more and 2000 μm or less. The upper limit of the thickness is more preferably 1000 μm, even more preferably 500 μm, even more preferably 300 μm, even more preferably 250 μm, even more preferably 200 μm, and even more preferably 150 μm, and the lower limit is more preferably 80 μm, and even more preferably 100 μm.

[0145] In particular, in the case of the adhesive sheet X2 shown in Figure 4, the thickness of the adhesive sheet is preferably 50 μm or more and 3000 μm or less. The upper limit of the thickness is more preferably 1000 μm, even more preferably 500 μm, even more preferably 300 μm, and the lower limit is more preferably 50 μm, even more preferably 100 μm, even more preferably 150 μm, and even more preferably 200 μm.

[0146] The manufacturing method for the adhesive sheet of this embodiment can be a known or conventional manufacturing method. For the electro-peelable adhesive layer in the adhesive sheet of this embodiment, one method is to apply a solution of the adhesive composition of this embodiment dissolved in a solvent as needed onto a release liner, and then dry and / or cure it. For other adhesive layers, one method is to apply a solution of the adhesive composition, which does not contain ionic liquids or additives, dissolved in a solvent as needed onto a release liner, and then dry and / or cure it. The solvent and release liner can be those listed above.

[0147] Conventional coaters (e.g., gravure roll coaters, reverse roll coaters, kiss roll coaters, dip roll coaters, bar coaters, knife coaters, spray roll coaters, etc.) can be used for application.

[0148] By the above method, an electrorelease adhesive layer and other adhesive layers can be manufactured, and the adhesive sheet of this embodiment can be manufactured by laminating the electrorelease adhesive layer and other adhesive layers onto a substrate, a conductive layer, and a conductive substrate as appropriate. Alternatively, instead of a release liner, an adhesive sheet may be manufactured by applying the adhesive composition to a substrate, a conductive layer, and a conductive substrate.

[0149] <Method for electrolytically removing adhesive sheets> In this embodiment, the adhesive sheet can be removed from the adherend by applying a voltage to the electrolytically removable adhesive layer, thereby creating a potential difference in the thickness direction of the electrolytically removable adhesive layer. For example, in the case of adhesive sheet X1, if the side with the electrolytically removable adhesive layer is an adherend having a conductive surface such as a metal adherend, the sheet can be removed by energizing the conductive adherend and the conductive layer 4 and applying a voltage to the electrolytically removable adhesive layer. In the case of adhesive sheet X2, the sheet can be removed by energizing the conductive layers 4 on both sides and applying a voltage to the electrolytically removable adhesive layer. It is preferable to connect terminals to one end and the other end of the adhesive sheet so that the voltage is applied to the entire electrolytically removable adhesive layer. Note that if the adherend has a conductive surface, the above-mentioned one end and the other end may be parts of the adherend having a conductive surface. Note that when removing the sheet, water may be added to the interface between the metal adherend and the electrolytically removable adhesive layer before applying the voltage.

[0150] <Initial adhesive strength, adhesive strength after voltage application, and adhesive strength reduction rate> The initial adhesive strength, adhesive strength after voltage application, and adhesive strength reduction rate of the electropeelable adhesive sheet of this embodiment can be evaluated by the 180° peel test described in this specification.

[0151] (Initial Adhesion) In this embodiment, the initial adhesion is preferably 3.0 N / cm or more. The initial adhesion can be, for example, 4.0 N / cm or more, 5.0 N / cm or more, 6.0 N / cm or more, 7.0 N / cm or more, 8.0 N / cm or more, 9.0 N / cm or more, or 10.0 N / cm or more. When the initial adhesion is 3.0 N / cm or more, the adhesion to the adherend is sufficient, and the adherend is less likely to peel off or shift.

[0152] Initial adhesive strength tends to increase with the selection of polymers with a low Tg, and / or the reduction of ionic substances, and / or the reduction of crosslinking agents, and / or the reduction of fillers, and tends to decrease with the selection of polymers with a high Tg, and / or the increase of ionic substances, and / or the increase of crosslinking agents, and / or the increase of fillers.

[0153] (Adhesive strength after voltage application) In this embodiment, it is preferable that the adhesive strength after voltage application is sufficiently small compared to the initial adhesive strength. It is preferable that the adhesive strength after voltage application is 1.0 N / cm or less. The adhesive strength after voltage application can be, for example, 0.5 N / cm or less, 0.3 N / cm or less, 0.1 N / cm or less, or 0.05 N / cm or less. An initial adhesive strength of 1.0 N / cm or less is preferable because it allows for non-destructive peeling even of fragile adherends.

[0154] The adhesive strength after voltage application can be adjusted by the polymer's Tg, and / or the viscosity of the ionic substance, and / or the amount of ionic substance added, and / or the amount of crosslinking agent added, and / or the amount of filler added. More specifically, the adhesive strength after voltage application tends to decrease, for example, by lowering the elastic modulus of the adhesive composition, and / or by selecting a highly mobile ionic substance, and / or by increasing the amount of ionic substance added, and / or by decreasing the amount of filler added. Even more specifically, it tends to decrease, for example, by selecting a polymer with a low Tg, and / or by decreasing the amount of crosslinking agent added, and / or by selecting a low-viscosity ionic substance.

[0155] Furthermore, the adhesion reduction rate, calculated from the adhesion strength after voltage application and the initial adhesion strength using the following formula, is preferably 60% or more, more preferably 70% or more, even more preferably 80% or more, and particularly preferably 90% or more. Adhesion reduction rate (%) = 100 - (Adhesion strength after voltage application / Initial adhesion strength) × 100 There is no particular upper limit to the adhesion reduction rate, but for example, it can be 99.999% or less.

[0156] The rate of decrease in adhesive strength can be adjusted by the same method as for adjusting the adhesive strength after voltage application, namely by the Tg of the polymer, and / or the viscosity of the ionic substance, and / or the amount of ionic substance added, and / or the amount of crosslinking agent added, and / or the amount of filler added.

[0157] The applied voltage and voltage application time during electrolysis are not particularly limited as long as the adhesive sheet can be peeled off. Preferred ranges are shown below. The applied voltage is preferably 1V or more, more preferably 3V or more, and even more preferably 6V or more. It is also preferably 100V or less, more preferably 50V or less, and even more preferably 30V or less. The voltage application time 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 especially preferably 30 seconds or less. In such cases, workability is excellent. The shorter the application time, the better, but it is usually 1 second or more.

[0158] <Applications of Adhesive Sheets> Conventional re-peelable technologies include adhesive layers that harden and peel off with ultraviolet (UV) irradiation or adhesive layers that peel off with heat. Adhesive sheets using such adhesive layers cannot be used when ultraviolet (UV) irradiation is difficult or when heat damages the adherend. The adhesive sheet of this embodiment, which has the above-mentioned electro-peelable adhesive layer, does not use ultraviolet light or heat, and can be easily peeled off by applying voltage without damaging the adherend.

[0159] The uses of the adhesive sheet according to the embodiment of the present invention are not particularly limited and can be used without restriction for various purposes. For example, the adhesive sheet can be used in a manner in which it is attached to a component constituting an electronic device, for example, for purposes such as fixing, joining, or reinforcing the component. The adhesive sheet according to the embodiment of the present invention is particularly suitable for fixing components of portable electronic devices. For example, a portable electronic device can be made that includes the adhesive sheet according to the embodiment of the present invention. The adhesive sheet according to the embodiment of the present invention can be preferably used, for example, in the form of a double-sided adhesive sheet for applications of fixing or joining components.

[0160] Furthermore, examples of rigid members to be joined by the adhesive sheet in this embodiment include silicon substrates for semiconductor wafer applications, sapphire substrates, SiC substrates and metal base substrates for LEDs, TFT substrates and color filter substrates for displays, and base substrates for organic EL panels. Examples of fragile members to be joined by the double-sided adhesive sheet include semiconductor substrates such as compound semiconductor substrates, silicon substrates for MEMS devices, passive matrix substrates, surface cover glass for smartphones, OGS (One Glass Solution) substrates in which a touch panel sensor is attached to the cover glass, organic substrates and organic-inorganic hybrid substrates mainly composed of silsesquioxane, flexible glass substrates for flexible displays, and graphene sheets.

[0161] [Bonded Body] The bonded body of this embodiment preferably comprises the electro-peelable adhesive sheet of this embodiment described above and a conductive material, wherein the electro-peelable adhesive layer is attached to the conductive material. The surface resistance of the conductive material to which the adhesive layer is attached is, for example, 1.0 × 10⁻⁶. ４ Ω / □ or less, preferably 1.0 × 10 ３ The surface resistance is less than or equal to Ω / □. The surface resistance can be calculated by dividing the resistivity measured by the four-terminal method by the thickness of the conductive material, in accordance with JIS K 7194 (1994). Furthermore, the surface resistance of the conductive material can be selected according to the intended use and conditions, i.e., the applied voltage conditions for stripping (whether high voltage or low voltage is desired). Lowering the surface resistance of the conductive material tends to lower the voltage required for stripping. For example, the surface resistance is 5.0 × 10⁻⁶. ２ It can also be less than or equal to Ω / □, and 1.0 × 10 ２ It may be less than or equal to Ω / □, less than or equal to 50Ω / □, less than or equal to 40Ω / □, or less than or equal to 30Ω / □.

[0162] Furthermore, it is also preferable that the joint of this embodiment comprises the adhesive sheet of this embodiment described above and an adherend material, wherein the other adhesive layer is attached to the adherend material.

[0163] The bonded body of this embodiment comprises the electro-peelable adhesive sheet of this embodiment described above and a conductive material, wherein the electro-peelable adhesive layer is bonded to the conductive material. For example, it may have a laminated structure including a conductive material and an adhesive sheet to which the electro-peelable adhesive layer is bonded. Examples of conductive materials include adherends having a metallic adhesion surface. Examples of metallic adhesion surfaces include surfaces made of metals mainly composed of aluminum, copper, iron, magnesium, tin, gold, silver, and lead, and among these, surfaces made of metals containing aluminum are preferred. Examples of adherends having a metallic adhesion surface include sheets, parts, and plates made of metals mainly composed of aluminum, copper, iron, magnesium, tin, gold, silver, and lead. The adherend having a metallic adhesion surface may be a non-conductive material having a conductive layer as its adhesion surface. While not particularly limited, non-conductive materials include, for example, Japanese paper, fine paper, kraft paper, crepe paper, cloth, and fibrous sheets such as woven and nonwoven fabrics, films and sheets made of various plastics (polyolefin resins such as polyethylene and polypropylene, polyester resins such as polyethylene terephthalate, acrylic resins such as polymethyl methacrylate, polyimide resins, etc.), plastic substrates such as housings, glass substrates, and laminates thereof. The adherend may be in the form of a single layer or a multi-layer structure. If necessary, various treatments such as rust prevention treatment, back treatment, antistatic treatment, and primer treatment may be applied.

[0164] Examples of the bonded bodies in this embodiment include an adhesive sheet X1 having an adherend with a metal adherend on the electro-peelable adhesive layer 1 side and an adherend on the other adhesive layer 2 side, and an adhesive sheet X2 having adherends on both sides of the other adhesive layer 2.

[0165] The following are disclosed herein: <1> A conductive substrate comprising a substrate and a conductive layer having a metal layer comprising at least one selected from a metal having a standard electrode potential of -1.67 [V vs. SHE] or higher, and an alloy containing the said metal. <2> The conductive substrate according to <1>, wherein the metal having a standard electrode potential of -1.67 [V vs. SHE] or higher is at least one selected from noble metals, Cr, Ni, Nb, Ti, V, W, Mo, and Zr. <3> The conductive substrate according to claim 1, wherein the crystal lattice of the metal having a standard electrode potential of -1.67 [V vs. SHE] or higher is a face-centered cubic lattice. <4> The conductive substrate according to any one of <1> to <3>, wherein the metal layer is a metal layer containing a Ni alloy. <5> The conductive substrate according to any one of <1> to <4>, wherein the surface of the conductive layer opposite to the substrate is a layer made of a Ni alloy. <6> The conductive substrate according to <4> or <5>, wherein the Ni alloy is a NiCr alloy, a NiV alloy, a NiTi alloy, or a NiNb alloy. <7> The conductive substrate according to any one of <4> to <6>, wherein the Ni alloy is a NiCr alloy with a Cr content of more than 0 atm% and 50 atm% or less, a NiV alloy with a V content of more than 0 atm% and 50 atm% or less, a NiTi alloy with a Ti content of more than 0 atm% and 50 atm% or less, or a NiNb alloy with a Nb content of more than 0 atm% and 50 atm% or less. <8> The conductive substrate according to any one of <4> to <6>, wherein the Ni alloy is a NiCr alloy with a Cr content of more than 0 atm% and 22 atm% or less, a NiV alloy with a V content of more than 0 atm% and 22 atm% or less, a NiTi alloy with a Ti content of more than 0 atm% and 22 atm% or less, or a NiNb alloy with a Nb content of more than 0 atm% and 22 atm% or less. <9> The conductive substrate according to any one of <4> to <6>, wherein the Ni alloy is a NiCr alloy with a Cr content of more than 0 atm% and 15 atm% or less, a NiV alloy with a V content of more than 0 atm% and 15 atm% or less, a NiTi alloy with a Ti content of more than 0 atm% and 15 atm% or less, or a NiNb alloy with a Nb content of more than 0 atm% and 15 atm% or less. <10> The conductive substrate according to any one of <1> to <9>, wherein the metal layer consists of a single layer.<11> A conductive substrate according to any one of <1> to <10>, wherein the conductive layer further comprises a silicon oxide layer. <12> A conductive substrate according to any one of <1> to <11>, wherein the surface of the substrate is treated for easy adhesion. <13> A conductive substrate according to any one of <1> to <12>, further comprising an easy adhesion layer. <14> A conductive substrate according to <1>, for electrolytic release and / or for fixing components in electrical and electronic equipment. <15> A conductive substrate according to <9>, for electrolytic release and / or for fixing components in electrical and electronic equipment. <16> An adhesive sheet comprising a conductive substrate according to any one of <1> to <15> and an adhesive layer. <17> An electrolytically released adhesive sheet comprising a conductive substrate according to any one of <1> to <6> or <10> to <14> and an electrolytically released adhesive layer whose adhesive strength decreases when a voltage is applied, wherein the conductive layer side surface of the conductive substrate and the electrolytically released adhesive layer are in contact. <18> An electropenetrating adhesive sheet comprising a conductive substrate according to any one of <7> to <9> or <15> and an electropenetrating adhesive layer whose adhesive strength decreases when a voltage is applied, wherein the conductive substrate's surface on the conductive layer side and the electropenetrating adhesive layer are in contact. <19> An electropenetrating adhesive sheet comprising a conductive substrate according to any one of <1> to <12> or <14> and an electropenetrating adhesive layer whose adhesive strength decreases when a voltage is applied, wherein the conductive substrate further comprises an easy-adhesion layer on the conductive layer side, and the easy-adhesion layer and the electropenetrating adhesive layer are in contact. <20> A bond comprising the electropenetrating adhesive sheet according to <17> and a conductive material, wherein the electropenetrating adhesive layer is attached to the conductive material. <21> A bond comprising the electropenetrating adhesive sheet according to <18> and a conductive material, wherein the electropenetrating adhesive layer is attached to the conductive material.

[0166] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples. The weight-average molecular weights listed below were measured by gel permeation chromatography (GPC). In principle, the acid value and softening point of the tackifying resin are based on catalog values, and if there are no catalog values, the measured values ​​are used. If there is a range in the catalog values, the median value is generally used.

[0167] [Examples 1-19, Comparative Example 1] <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 placed in 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 temperature was raised to 63°C and the reaction was carried out for 6 hours. Then, ethyl acetate was added to obtain acrylic polymer solution 1 with a solid content of 40% by mass. The weight-average molecular weight of the obtained acrylic polymer 1 was 750,000.

[0168] <Preparation of Adhesive Compositions> Using the acrylic polymer solution 1 obtained above, and the ionic liquid, crosslinking agent, corrosion inhibitor, and tackifying resin components shown below, as described in Table 1, the mixture was stirred and mixed to obtain electro-peelable adhesive composition (solution) A and electro-peelable adhesive composition (solution) B, adjusted to a solid content concentration of 25% by mass. Ethyl acetate was used to adjust the solid content concentration of the adhesive composition. The values ​​for each component represent parts by mass. The polymer content (parts by mass) indicates the content as solids (parts by mass).

[0169]

[0170] The abbreviations for each component in Table 1 are as follows:

[0171] (Ionic substances) AS-110: Cation: 1-ethyl-3-methylimidazolium cation, Anion: bis(fluorosulfonyl)imide anion, Trade name "Elexel AS-110", Manufactured by Daiichi Kogyo Seiyaku Co., Ltd. (Crosslinking agent) V-05: Carbodiimide-containing polymer, Manufactured by Nisshinbo Chemical Co., Ltd. (Corrosion inhibitor) Irgamet30: N,N-bis(2-ethylhexyl)-1,2,4-triazole-1-ylmethaneamine, Trade name "Irgamet30", Manufactured by BASF IrgacorDSSG: Sodium sebacate, Trade name "IrgacorDSSG", Manufactured by BASF AmineO: Imidazolin derivative, Trade name "Amine O", Manufactured by BASF (Tackifying resin) Acrylic oligomer (acrylic tackifier): As oligomer monomer components prepared by the following procedure, 95 parts by mass of cyclohexyl methacrylate (CHMA), 5 parts by mass of acrylic acid (AA), 300 parts by mass of ethyl acetate as a polymerization solvent, and 3 parts by mass of 2-mercaptoethanol (thioglycol) as a chain transfer agent were placed in 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, the temperature was raised to 65°C and the reaction was carried out for 3 hours, followed by the reaction at 75°C for 2 hours to obtain an acrylic oligomer with a solid content of 25% by mass. The weight-average molecular weight of the acrylic oligomer was 4000. Pencel D-125: Polymerization rosin, manufactured by Arakawa Chemical Industries, Ltd.

[0172] <Preparation of Electrorelease Adhesive Layer> The electrorelease adhesive composition (solution) A obtained above was applied to the peeled surface of a polyethylene terephthalate peel liner (product name "MRF38", manufactured by Mitsubishi Chemical Corporation) using an applicator to achieve a uniform thickness. Next, it was heated and dried at 150°C for 3 minutes, and then laminated onto the peeled surface of the polyethylene terephthalate peel liner (product name "MRE38", manufactured by Mitsubishi Chemical Corporation) using a hand roller to obtain an electrorelease adhesive layer A with a thickness of 50 μm. An electrorelease adhesive layer B with a thickness of 50 μm was also obtained by the same procedure.

[0173] <Preparation of Conductive Substrates> A substrate (polyethylene terephthalate) was prepared. Two types of substrates were prepared: one with an easy-adhesion layer and one without. Next, for Examples 1 to 18 and Comparative Example 1, the conductive substrates for each example and comparative example shown in Tables 2 and 3 were prepared by depositing a base layer (SiOx layer), a metal layer, and an easy-adhesion layer (carbon (C)) in that order on the substrate surface under the following conditions, using the DC magnetron sputtering method (sputtering) for Example 19 and vacuum resistance deposition (deposition). When using a substrate with an easy-adhesion layer, the films were sequentially deposited on the surface of the substrate with the easy-adhesion layer.

[0174] Film formation method: DC magnetron sputtering method Substrate (without easy-adhesion layer): PET (polyethylene terephthalate, thickness approx. 25 μm), manufactured by Toray Industries, Inc. Product name: Lumirror S10 Substrate (with easy-adhesion layer): PET (polyethylene terephthalate, thickness approx. 25 μm), manufactured by Toray Industries, Inc. Product name: Lumirror U48 Film thickness of each layer: SiOx layer: 3 nm, each metal layer: as shown in the table Film formation power: Si 1 kW, SUS304 5.3 kW, Nb 3.6 kW, Ti 5 kW, Ni ５０ Cr ５０ 2.5kW, Ni ６２ Cr ３８ 2.5kW, Ni ７８ Cr ２２ 2.5kW, Ni ８５ Cr １５ 2.5kW, Ni ９２ Cr ８ 2.5kW, Ni ９４ Cr ６ 2.5kW, Ni ８９ Ti １１ 2.1 kW, Ni ７９ Ti ２１ 2.1 kW, Ni ８９ Nb １１ 2.0 kW, Ni ７９ Nb ２１ 2.0 kW, Ni 1.7 kW, C 7 kW; Film deposition pressure: Argon 0.2 Pa; Substrate temperature: Room temperature

[0175] Film formation method: Vacuum resistance deposition substrate (with easy-adhesion layer): PET (polyethylene terephthalate, thickness approximately 25 μm), manufactured by Toray Industries, Inc., product name: Lumirror U48 Film thickness of each layer: SiOx layer: 3 nm, Ni layer: 20 nm Material: Ni (powder, purity: 99.99%) Equipment name: ULVAC "High Vacuum Deposition System EX-550" Board: Tungsten board Vacuum level: 5 × 10⁻³ Pa Substrate temperature: Room temperature

[0176] The ratios of NiCr alloy, NiTi alloy, and NiNb alloy are expressed in atm%.

[0177] <Measurement of film thickness of each layer> The thickness of the base layer, metal layer, and easy-adhesion layer (carbon (C)) was determined by the following observations. Specifically, for the laminate, a cross-section was prepared using the FIB microsampling method, and FE-TEM observation was performed. In addition, elemental analysis was performed by TEM-EDX measurement. The measurement equipment and conditions are as follows.

[0178] - FIB system: Hitachi FB2200, acceleration voltage: 40kV - FE-TEM system: JEOL JEM-2800, acceleration voltage: 200kV - EDX system: Thermo Fisher Scientific NORAN System 7, incident electron probe diameter approximately 1nmφ

[0179] <Measurement of elemental ratios of alloy> A qualitative analysis was performed on the sputter-deposited alloy using a scanning X-ray fluorescence analyzer (Rigaku Corporation, product name "ZSX Primus III+"), and the resulting 1 cm³ was obtained. ２ The number of atoms in each element was determined by dividing the mass per unit area (μg) by the atomic weight of each element, and the atomic weight percentage (atm%) was calculated.

[0180] <Preparation of a single-sided adhesive sheet with a substrate> The electro-peelable adhesive layer A obtained above was made into a sheet with dimensions of 10 mm x 80 mm, the release liner (MRE38) was peeled off, and the metal layer side of the conductive substrate prepared above was bonded to the exposed electro-peelable adhesive layer surface to create a single-sided adhesive sheet with a substrate.

[0181] <Preparation of the bonded body> The release liner (MRF38) of the single-sided adhesive sheet with a substrate obtained above was peeled off, and a stainless steel plate was attached to the peeled surface so that one end of the adhesive sheet protruded from the substrate by about 2 mm. The sheet was then pressed once back and forth with a 2 kg roller, and left to stand for 30 minutes in an environment of 22°C to obtain a bonded body consisting of a stainless steel plate, an electro-peelable adhesive layer A, and a conductive substrate.

[0182] <Evaluation> (Electrical Peel Repeatability) A stainless steel plate (SUS316, size: 30 mm x 120 mm) was used as the adherend. A bonded body was prepared according to the above procedure, and before peeling, the negative and positive electrodes of a DC current machine were attached to the β and α locations in Figure 5 of the bonded body, respectively, and a voltage of 30 V was applied for 30 seconds. Immediately after the voltage application was completed, the adhesive sheet was peeled in the direction of the arrow in Figure 5 using a peel test machine (product name "Variable Angle Peel Test Machine YSP", manufactured by Asahi Seiko Co., Ltd.), and the adhesive strength in the 180° peel test (tensile speed: 300 mm / min, peel temperature 23°C) was measured and defined as the electropeel strength. The adhesive strength used was the value calculated in accordance with Method 1 for Measuring Peel Adhesion of Adhesion as described in JIS Z 0237:2009. Subsequently, the detached adhesive sheet was reassembled into a bonded structure according to the above procedure, and the process of peeling the sheet immediately after applying voltage according to the above procedure was repeated. The number of times until the metal layer peeled off from the substrate and could no longer be re-adhered was recorded as the electro-peelability repeatability. The above procedure was repeated up to a maximum of 10 times.

[0183] (Corrosion) A stainless steel plate (SUS316, size: 30 mm x 120 mm) was used as the adherend. A joint was prepared according to the above procedure, and the joint was stored in a constant temperature and humidity chamber at 60°C and 90% RH for 504 hours (3 w). After removal, it was left to stand at 22°C and 50% RH for 72 hours. The joint after storage was visually evaluated based on the following criteria. The criteria were as follows, and corrosion was judged when the conductive substrate lost its metallic luster and became transparent (discolored). ○: No corrosion at the entire joint between the electropenetrating adhesive layer A and the conductive substrate ×: Part of the joint between the electropenetrating adhesive layer A and the conductive substrate was corroded

[0184] (Discoloration) A stainless steel plate (SUS316, size: 30 mm x 120 mm) was used as the adherend. A bonded body was prepared according to the above procedure, and the bonded body was stored in a constant temperature and humidity chamber at 60°C and 90% RH for 504 hours (3 w). After removal, it was left to stand at 22°C and 50% RH for 72 hours. The bonded body after storage was visually evaluated based on the following criteria. The criteria were as follows: Discoloration was determined when the conductive substrate had not lost its metallic luster, but its original color or luster had changed. ○: No discoloration at the entire joint between the electropenetrating adhesive layer A and the conductive substrate. ×: Part of the joint between the electropenetrating adhesive layer A and the conductive substrate was discolored.

[0185] (Electrodeposition force after humidification and heat) After corrosion and discoloration evaluation, the negative and positive electrodes of a DC current machine were attached to locations β and α in Figure 5 of the joint, respectively, and a voltage of 30V was applied for 30 seconds, and the voltage was left on. Immediately after the end of the voltage application, the adhesive strength after voltage application was measured according to the procedure described above and defined as the electrodeposition force.

[0186] (Adhesion) The adhesion between the conductive substrate (easy-adhesion layer) and the electro-release adhesive layer B of each example and comparative example was measured. The adhesion values ​​between the conductive substrate (easy-adhesion layer) and the electro-release adhesive layer B were measured using the adhesion values ​​obtained with a PET film with a primer layer. First, a single-sided adhesive sheet with a substrate for adhesion measurement was prepared in the same manner as in the above <Preparation of single-sided adhesive sheet with substrate>, except that the electro-release adhesive layer A was replaced with electro-release adhesive layer B.

[0187] A PET film with a primer layer was prepared using the following procedure. A coating solution for forming the primer layer was prepared by mixing 1 part of a solution containing an oxazoline group-containing acrylic polymer (product name "Epochross WS-700", manufactured by Nippon Shokubai Co., Ltd.) and 99 parts of water. The prepared coating solution was applied to a PET film (product name "Lumirror S-10", manufactured by Toray Industries, Inc., 25 μm thick) using a Meyer bar #5 and dried at 40°C for 120 seconds to form a primer layer. The resulting PET film with a primer layer was cut to a size of 30 mm in width and 150 mm in length.

[0188] The single-sided adhesive sheet with a base material prepared as described above was cut to a size of 20 mm in width and 140 mm in length. Next, the conductive base material side of the single-sided adhesive sheet with a base material was attached to a stainless steel plate (SUS316 plate) via double-sided adhesive tape (product name "No. 531", manufactured by Nitto Denko Corporation), obtaining a laminate having a laminated structure of stainless steel plate / double-sided adhesive tape / conductive base material / electro-peelable adhesive layer B. The pressure applied during attachment was achieved by rolling a 2 kg roller back and forth once.

[0189] Under conditions of 22°C and 50% RH, the release liner (MRF38) was peeled off the laminate obtained above, and the primer layer side of the PET film with a primer layer prepared above was attached to the exposed electro-peelable adhesive layer B by rolling a 2 kg roller back and forth once, thereby obtaining a laminate 1 having a laminated structure of stainless steel plate / double-sided adhesive tape / conductive substrate / electro-peelable adhesive layer B / PET film with primer layer.

[0190] Laminate 1 was left to stand for 72 hours in an environment of 22°C and 50% RH to obtain a test specimen. The test specimen was set in a peel tester (product name "Variable Angle Peel Tester YSP", manufactured by Asahi Seiko Co., Ltd.), and a 180° peel test (tensile speed: 300 mm / min, peel temperature 22°C, humidity 50% RH) was performed to peel off the conductive substrate and the electropenetrating adhesive layer B. The adhesive strength [N / cm] at that time was defined as the adhesion strength. The adhesive strength was calculated according to the measurement method 1 of peel adhesion strength described in JIS Z 0237:2009. In addition, values ​​that were not measured are indicated with "-" in the table.

[0191] <Measurement of sheet resistance before and after stretching> A conductive substrate was cut into a 3 cm x 15 cm sheet, and the sheet was stretched using a Shimadzu Autograph AGX-V under a measurement environment of 22°C and 50% RH. The conductive substrate was fixed by clamping it with arms so that the distance between stretching points, i.e., the distance between chucks, was 10 cm, and the sheet was stretched by 0.5 cm in the longitudinal direction of the plane (5% stretch) by pulling at a speed of 5 mm / min for 1 minute. The stretched conductive substrate was cut into a 3 cm x 10 cm sheet, and carbon double-sided tape manufactured by Nissin EM Co., Ltd. was attached to both ends of the sample to prevent damage to the conductive substrate due to terminal connection. Subsequently, under a measurement environment of 22°C and 50% RH, the resistance value was measured using a Keithley Instruments 2100 6 1 / 2 Digit Multimeter by the terminals of the carbon double-sided tape and the resistance value was measured using the two-terminal method. This was then converted to the sheet resistance value using the following formula (sheet resistance value after 5% stretching). This sheet resistance value measurement was performed within 7 hours of stretching the sheet. Conversion formula: Sheet resistance value Ω / □ = (resistance Ω × 3 cm) / 10 cm The sheet resistance value (initial sheet resistance value) of the conductive substrate before stretching was also determined according to the above procedure.

[0192] The above examples, comparative examples, and measurement results are shown in Tables 2 and 3.

[0193]

[0194]

[0195] As shown in Tables 2 and 3, the adhesive sheets using conductive substrates of Examples 1 to 19, which have a conductive layer containing a specific metal, exhibited excellent resistance to humid heat and could be used repeatedly. In contrast, the adhesive sheet using the conductive substrate of Comparative Example 1 underwent corrosion of the metal vapor-deposited film after being exposed to a humid heat environment for a long period of time before use. Furthermore, the metal vapor-deposited film contained in the conductive substrate peeled off from the substrate after being used five times.

[0196] The present invention is not limited to the embodiments described above, and various modifications are possible within the scope of the claims. Embodiments obtained by appropriately combining the technical means disclosed in different embodiments are also included in the technical scope of the present invention.

[0197] The present invention can provide a conductive substrate that has excellent resistance to moist heat and can be used repeatedly, and an adhesive sheet containing the conductive substrate.

[0198] Although the present invention has been described in detail and with reference to specific embodiments, it will be apparent to those skilled in the art that various changes and modifications can be made without departing from the spirit and scope of the invention. This application is based on Japanese Patent Application No. 2024-161378 filed on 18 September 2024, Japanese Patent Application No. 2025-031917 filed on 28 February 2025, and Japanese Patent Application No. 2025-044838 filed on 19 March 2025, the contents of which are incorporated herein by reference.

[0199] X1, X2 Adhesive Sheet 1 Electrorelease Adhesive Layer 2 Other Adhesive Layer 3 Substrate 4 Conductive Layer 5 Conductive Substrate 6 Metal Layer 7 Underlayer 10 Conductive Adhesion

Claims

1. A conductive substrate comprising a base material and a conductive layer having a metal layer containing at least one selected from a metal having a standard electrode potential of -1.67 [V vs. SHE] or higher, and an alloy containing the said metal.

2. The conductive substrate according to claim 1, wherein the metal having a standard electrode potential of -1.67 [V vs. SHE] or higher is at least one selected from noble metals, Cr, Ni, Nb, Ti, V, W, Mo, and Zr.

3. The conductive substrate according to claim 1, wherein the crystal lattice of the metal having a standard electrode potential of -1.67 [V vs. SHE] or higher is a face-centered cubic lattice.

4. The conductive substrate according to claim 1, wherein the metal layer is a metal layer containing a Ni alloy.

5. The conductive substrate according to claim 1, wherein the surface of the conductive layer opposite to the substrate is a layer made of a Ni alloy.

6. The conductive substrate according to claim 4, wherein the Ni alloy is a NiCr alloy, a NiV alloy, a NiTi alloy, or a NiNb alloy.

7. The conductive substrate according to claim 4, wherein the Ni alloy is any one of the following: a NiCr alloy with a Cr content of more than 0 atm% and 50 atm% or less; a NiV alloy with a V content of more than 0 atm% and 50 atm% or less; a NiTi alloy with a Ti content of more than 0 atm% and 50 atm% or less; or a NiNb alloy with a Nb content of more than 0 atm% and 50 atm% or less.

8. The conductive substrate according to claim 4, wherein the Ni alloy is any one of the following: a NiCr alloy with a Cr content of more than 0 atm% and 22 atm% or less; a NiV alloy with a V content of more than 0 atm% and 22 atm% or less; a NiTi alloy with a Ti content of more than 0 atm% and 22 atm% or less; or a NiNb alloy with a Nb content of more than 0 atm% and 22 atm% or less.

9. The conductive substrate according to claim 4, wherein the Ni alloy is any one of the following: a NiCr alloy with a Cr content of more than 0 atm% and 15 atm% or less; a NiV alloy with a V content of more than 0 atm% and 15 atm% or less; a NiTi alloy with a Ti content of more than 0 atm% and 15 atm% or less; or a NiNb alloy with a Nb content of more than 0 atm% and 15 atm% or less.

10. The conductive substrate according to claim 1, wherein the metal layer consists of a single layer.

11. The conductive substrate according to claim 1, wherein the conductive layer further comprises a silicon oxide layer.

12. The conductive substrate according to claim 1, wherein the surface of the substrate is treated with an easy-adhesion treatment.

13. The conductive substrate according to claim 1, further comprising an easy-adhesion layer.

14. The conductive substrate according to claim 1, which is for electrolytic stripping and / or for fixing components in electrical and electronic equipment.

15. The conductive substrate according to claim 9, which is for electrolytic stripping and / or for fixing components in electrical and electronic equipment.

16. An adhesive sheet comprising a conductive substrate according to any one of claims 1 to 15 and an adhesive layer.

17. An electropenetrating adhesive sheet comprising a conductive substrate according to any one of claims 1 to 6 or 10 to 14, and an electropenetrating adhesive layer whose adhesive strength decreases when a voltage is applied, wherein the conductive substrate side surface and the electropenetrating adhesive layer are in contact.

18. An electropenetrating adhesive sheet comprising a conductive substrate according to any one of claims 7 to 9 or 15, and an electropenetrating adhesive layer whose adhesive strength decreases when a voltage is applied, wherein the conductive substrate side surface and the electropenetrating adhesive layer are in contact.

19. An electropenetrating adhesive sheet comprising a conductive substrate according to any one of claims 1 to 12 or 14, and an electropenetrating adhesive layer whose adhesive strength decreases when a voltage is applied, wherein the conductive substrate further comprises an easy-adhesion layer on the surface facing the conductive layer, and the easy-adhesion layer and the electropenetrating adhesive layer are in contact.

20. A bond comprising an electropenetrating adhesive sheet as described in claim 17 and a conductive material, wherein the electropenetrating adhesive layer is attached to the conductive material.

21. A bond comprising an electropenetrating adhesive sheet as described in claim 18 and a conductive material, wherein the electropenetrating adhesive layer is attached to the conductive material.

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