Electrically peelable adhesive sheet and method of using the same

Abstract

Provided is an electro-peelable pressure-sensitive adhesive sheet having a pressure-sensitive adhesive structure including a pressure-sensitive adhesive layer formed from an electro-peelable pressure-sensitive adhesive composition and a plurality of conductive linear bodies. The adhesive strength of the electro-peelable pressure-sensitive adhesive sheet can be easily adjusted by applying a voltage.

Description

[Technical Field]

[0001] The present invention relates to an electrically peelable pressure-sensitive adhesive sheet and a method for using the electrically peelable pressure-sensitive adhesive sheet. [Background technology]

[0002] One of the properties required of pressure-sensitive adhesive sheets is removability, for example, in applications such as temporary fixing tapes, surface protection films, painting or decorative masking tapes, and removably removable memos. When applied to an adherend, a removable adhesive sheet is required to have sufficient adhesive strength so that it does not peel off from the adherend during transportation, storage, processing, etc., but is also required to be removable so that it can be easily removed after it has completed its function.

[0003] Known adhesives and adhesive sheets that can reduce their adhesive strength by applying a voltage are used in such removable adhesive sheets. For example, Patent Document 1 discloses an electric peeling composition containing an ionic liquid as a pressure-sensitive adhesive that can be peeled off when a voltage is applied. Patent Document 1 describes a method in which, when the electric peeling composition is used as an adhesive, it is intended to be used to bond two conductive members, and a voltage is applied between one conductive member and the other conductive member bonded together using the adhesive to peel the other conductive member from the other conductive member. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] WO2007 / 018239 issue Summary of the Invention [Problem to be solved by the invention]

[0005] However, the electro-peeling composition containing an ionic liquid described in Patent Document 1 is intended for use as an adhesive or coating, and no studies have been conducted on its use in sheet form. Therefore, there is a need for a new electrically peelable pressure-sensitive adhesive sheet whose adhesive strength can be easily adjusted by applying a voltage. [Means for solving the problem]

[0006] The present invention provides an electrically peelable pressure-sensitive adhesive sheet having an adhesive structure including a pressure-sensitive adhesive layer formed from an electrically peelable pressure-sensitive adhesive composition and a plurality of conductive linear members. Specifically, the present invention provides the following aspects [1] to

[12] . [1] An electrically peelable pressure-sensitive adhesive sheet having an adhesive structure including a pressure-sensitive adhesive layer formed from an electrically peelable pressure-sensitive adhesive composition and a plurality of conductive linear bodies. [2] The electrically peelable adhesive sheet according to [1] above, wherein the adhesive structure has a structure in which the adhesive layer encapsulates at least a portion of the plurality of conductive linear bodies extending in one direction. [3] An electrically peelable adhesive sheet according to [1] or [2] above, in which the plurality of conductive linear members are not exposed on the surface of the adhesive layer that is attached to the substrate. [4] The electrically peelable adhesive sheet according to any one of [1] to [3] above, wherein the average outer diameter (X2) of the cross section of the plurality of conductive linear bodies in the thickness direction of the adhesive structure is smaller than the thickness (X1) of the adhesive layer. [5] The electrically peelable adhesive sheet according to any one of the above [1] to [4], wherein in a cross section of the adhesive structure in the thickness direction, the ratio [(X2) / (X1)] of the average outer diameter (X2) of the cross section of the plurality of conductive linear bodies to the thickness (X1) of the adhesive layer is 0.01 to 0.95. [6] The electrically peelable pressure-sensitive adhesive sheet according to any one of the above [1] to [5], wherein the pressure-sensitive adhesive layer has a thickness (X1) of 5 to 200 μm. [7] The electrically peelable adhesive sheet according to any one of [1] to [6] above, wherein, when the adhesive structure is viewed in a plane, the plurality of conductive linear members are arranged so as to be approximately parallel to each other. [8] The volume resistivity of the conductive linear body is 1.0 × 10 -9 ~1.0×10 1 The electrically peelable pressure-sensitive adhesive sheet according to any one of the above [1] to [7], which has a resistance of Ω·m. [9] The electrically peelable adhesive sheet according to any one of the above [1] to [8], which has the adhesive structure on at least one surface side of a substrate.

[10] The electrically peelable pressure-sensitive adhesive sheet according to any one of the above [1] to [9], which has a current collector electrically connected to the plurality of conductive linear members.

[11] The electrically peelable pressure-sensitive adhesive sheet according to any one of the above [1] to

[10] , which is used by being attached to an adherend made of a conductive material.

[12] A method for using an electrically peelable adhesive sheet, comprising applying the electrically peelable adhesive sheet according to any one of [1] to

[11] above to an adherend made of a conductive material, and then peeling the sheet from the adherend by applying a voltage to the plurality of conductive linear bodies. [Effects of the Invention]

[0007] The electrically releasable pressure-sensitive adhesive sheet of a preferred embodiment of the present invention has high adhesive strength before voltage application, but the adhesive strength can be easily reduced by voltage application. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a schematic cross-sectional view in the thickness direction of an electrically peelable pressure-sensitive adhesive sheet, illustrating an example of the configuration of the pressure-sensitive adhesive sheet of one embodiment of the present invention. [Figure 2] FIG. 1(a) is a schematic perspective view of an adhesive sheet showing an example of the configuration of an adhesive structure, taking as an example the electrically peelable adhesive sheet 1 according to one embodiment of the present invention shown in FIG. 1(a). [Figure 3] This is a schematic cross-sectional view of the electrically peelable adhesive sheet 1a shown in Figure 2(a) when cut in the thickness direction Z along a straight line Y1-Y2 extending in a direction Y perpendicular to the direction X in which multiple conductive linear bodies 22 extend. [Figure 4] FIG. 1 is a schematic perspective view showing an example of a method of using an electrically peelable pressure-sensitive adhesive sheet according to one embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0009] The numerical ranges described herein can be any combination of upper and lower limits. For example, when a numerical range is described as "preferably 20 to 120, more preferably 40 to 90," the ranges "20 to 90" and "40 to 120" are also included in the numerical ranges described herein. Furthermore, when a numerical range is described as "preferably 20 or more, more preferably 40 or more, and preferably 120 or less, more preferably 90 or less," the ranges "20 to 90" and "40 to 120" are also included in the numerical ranges described herein. In addition, as a numerical range described in this specification, for example, "60 to 100" means a range of "60 or more and 100 or less."

[0010] In this specification, for example, "(meth)acrylate" is used as a term indicating both "acrylate" and "methacrylate," and the same applies to other similar terms. The "active ingredient" of the electrically peelable pressure-sensitive adhesive composition means the components contained in the electrically peelable pressure-sensitive adhesive composition excluding the diluting solvent such as water or an organic solvent.

[0011] In this specification, whether an object is "conductive" or not can be determined based on the following test method. (Test method to determine whether conductive or not) An electrical circuit is created by connecting the object via a lead wire to the middle of an electrical circuit made by connecting a voltage application device and a miniature light bulb in series. The tip of the lead wire is connected to the adherend by touching it to the surface of the object. A voltage of 2.5V is applied using a DC power supply device, and when a voltage is passed through the created electrical circuit, it is visually observed whether the miniature light bulb lights up. If the miniature light bulb is confirmed to light up, the object is judged to be "conductive." On the other hand, if the light bulb is not confirmed to light up, the object is judged to be "non-conductive (insulating)."

[0012] In this specification, whether or not a target pressure-sensitive adhesive layer has "electrical peelability" can be determined based on the following test method. (Test method to determine whether or not it is electrolytically peelable) A test sheet is prepared by laminating aluminum foil (for example, "Aluminum Tantaite S Glossy 50 Fukuoka" manufactured by Nippon Kinzoku Foil Industries Co., Ltd., thickness: 50 μm) on one adhesive surface of the target adhesive layer. The other adhesive surface of the adhesive layer of the test sheet is attached to a stainless steel plate (SUS304, 360 grit polished) that serves as the adherend, and the test sheet is pressed against the adherend by rolling it back and forth once using a 2 kg roller. After application, the sheet is left to stand for 30 minutes in an environment of 23°C and 50% RH (relative humidity), and this is used as the measurement sample. Two measurement samples are prepared, and one of the measurement samples is peeled from the substrate using a tensile testing machine (for example, Orientec's Tensilon product) at a peel rate of 300 mm / min and a peel angle of 180° under conditions of 23°C and 50% RH (relative humidity). The value measured when peeling the test sheet of the measurement sample from the substrate (unit: N / 25 mm) is taken as the adhesive strength before voltage application. Next, a voltage application device (e.g., Takasago Machinery Works, product name "KH-100H") is used to connect the anode terminal to the aluminum foil of the test sheet and the cathode terminal to the stainless steel plate that is the adherend, and a voltage of 10 V is applied for 60 seconds. After the voltage application, the sample is left for 1 minute, and then the test sheet of the measurement sample is peeled off using a tensile tester at a peel rate of 300 mm / min and a peel angle of 180° under conditions of 23°C and 50% RH (relative humidity). The value measured when the test sheet of the measurement sample is peeled off (unit: N / 25 mm) is taken as the adhesive strength after voltage application. The adhesive strength reduction rate is calculated from the adhesive strength values ​​before and after voltage application using the following formula (f1). Formula (f1): [Adhesive strength reduction rate (%)] = 100 - [Adhesive strength after voltage application] / [Adhesive strength before voltage application] x 100 If the adhesive strength reduction rate is 30% or more, the adhesive layer to be measured is determined to be an "electrically releasing adhesive layer." On the other hand, if the adhesive strength reduction rate is less than 70%, the adhesive layer to be measured is determined to be a "non-electrically releasing adhesive layer."

[0013] [Configuration of the electrically releasable adhesive sheet] The electrically peelable adhesive sheet of the present invention (hereinafter also simply referred to as "adhesive sheet") has an adhesive structure including an adhesive layer formed from an electrically peelable adhesive composition (hereinafter also simply referred to as "adhesive composition") and a plurality of conductive linear bodies. The adhesive sheet of one embodiment of the present invention may be configured to have the adhesive structure, and may be, for example, a substrate-attached adhesive sheet having the adhesive structure on at least one surface side of the substrate, or a substrate-free adhesive sheet having the adhesive structure sandwiched between two release sheets.

[0014] Fig. 1 is a schematic cross-sectional view of an example of the configuration of a pressure-sensitive adhesive sheet according to one embodiment of the present invention. Note that, in each of the schematic cross-sectional views in Fig. 1, the pressure-sensitive adhesive layer and the plurality of conductive linear members that constitute the pressure-sensitive adhesive structure are omitted. A specific example of the configuration of the pressure-sensitive adhesive structure will be described later with reference to Figs. 2 and 3, etc.

[0015] A specific example of the structure of the pressure-sensitive adhesive sheet of one embodiment of the present invention is an electrically releasable pressure-sensitive adhesive sheet 1 having a pressure-sensitive adhesive structure 20 on one surface side of a substrate 10, as shown in FIG. 1(a). 1(b), the electrically peelable adhesive sheet 2 may have an adhesive structure 20, 20' on each surface of the substrate 10. The adhesive structure 20 and the adhesive structure 20' may be composed of the same adhesive composition and conductive linear body, or may be composed of different adhesive compositions and conductive linear bodies. The adhesive structure 20 and the adhesive structure 20' may have the same arrangement of the conductive linear bodies, or may have different arrangements.

[0016] Additionally, the pressure-sensitive adhesive sheet of one embodiment of the present invention may be configured such that the substrate 10 and the adhesive structure 20 are directly laminated together, as in the electrically releasing pressure-sensitive adhesive sheet 1 shown in Fig. 1(a), or may have another layer between the substrate 10 and the adhesive structure 20. Similarly, the electrically releasing pressure-sensitive adhesive sheet 2 shown in Fig. 1(b) may also have another layer between the substrate 10 and the adhesive structure 20 or between the substrate 10 and the adhesive structure 20'.

[0017] 1(c), the pressure-sensitive adhesive sheet of one embodiment of the present invention may have a configuration similar to that of an electrically releasing pressure-sensitive adhesive sheet 3 in which a release sheet 30 is further laminated on the adhesive surface of an adhesive structure 20. Similarly, the electrically releasing pressure-sensitive adhesive sheet 2 may also have a configuration in which a release sheet is laminated on each of the adhesive surfaces of the adhesive structures 20, 20′.

[0018] In another embodiment, the adhesive sheet of one embodiment of the present invention may be configured as a substrate-free electrically releasable adhesive sheet 4, as shown in Figure 1(d), in which an adhesive structure 20 is sandwiched between two release sheets 30, 30' without using a substrate. The materials of the release sheets 30 and 30' of this electrically peeling adhesive sheet 4 may be the same or different, but it is preferable that the materials are adjusted so that the release strength of the release sheets 30 and 30' is different.

[0019] Other examples include an electrically peelable adhesive sheet having a configuration in which an adhesive layer is provided on one side of a release sheet whose surface has been subjected to a release treatment, and the sheet is wound into a roll. Hereinafter, each of the components of the pressure-sensitive adhesive sheet according to one embodiment of the present invention will be described.

[0020] [Adhesive structure] FIG. 2 is a schematic perspective view of an adhesive sheet showing an example of the configuration of the adhesive structure, taking as an example the electrically peelable adhesive sheet 1 according to one embodiment of the present invention shown in FIG. 1(a). The adhesive structure of the adhesive sheet of one aspect of the present invention preferably has a structure in which the adhesive layer encapsulates at least some of a plurality of conductive linear bodies extending in one direction. For example, an adhesive sheet according to one embodiment of the present invention may have an adhesive structure 20 in which an adhesive layer 21 encapsulates a plurality of conductive linear bodies 22 extending in one direction (direction X in FIG. 2), as in the electrically peelable adhesive sheet 1a shown in FIG. 2(a). Furthermore, the pressure-sensitive adhesive sheet of one embodiment of the present invention may have an adhesive structure 20 in a structure in which the adhesive layer 21 encapsulates some of the plurality of conductive linear bodies 22 extending in one direction (direction X in FIG. 2), as in the electrically peelable adhesive sheet 1a shown in FIG. 2(b). Note that while FIG. 2(b) shows a configuration in which the plurality of conductive linear bodies 22 that are not encapsulated in the adhesive layer 21 are exposed from one end of the adhesive structure 20, the plurality of conductive linear bodies 22 that are not encapsulated in the adhesive layer 21 may also be exposed from the other end of the adhesive structure 20. In other words, the adhesive structure included in the pressure-sensitive adhesive sheet of one embodiment of the present invention may have a configuration in which the plurality of conductive linear bodies 22 that are not encapsulated in the adhesive layer 21 are exposed from both end portions.

[0021] Furthermore, from the viewpoint of workability when applying a voltage to the pressure-sensitive adhesive laminate, the pressure-sensitive adhesive sheet of one embodiment of the present invention preferably has a current collector electrically connected to a plurality of conductive linear members. The current collector may be provided so as to be electrically connected to the plurality of conductive linear bodies. A specific configuration may be such that at least a portion of the current collector 41 is in contact with the plurality of conductive linear bodies 22 and is encapsulated together with the plurality of conductive linear bodies 22 in the adhesive layer 21, as in the electrically peelable pressure-sensitive adhesive sheet 1c shown in Fig. 2(c). In addition, as in the electrically peelable adhesive sheet 1d shown in Figure 2(d), the current collector 41 may be configured to be connected to multiple conductive linear bodies 22 at locations that are not enclosed in the adhesive layer 21.

[0022] Furthermore, in the pressure-sensitive adhesive sheet of one embodiment of the present invention, as shown in Fig. 2, when the pressure-sensitive adhesive structure 20 is viewed in plan, the plurality of conductive linear bodies 22 are preferably arranged so as to extend in one direction (direction X in Fig. 2). When a voltage is applied to the plurality of conductive linear bodies 22, the adhesive strength of the adhesive layer in contact with the conductive linear bodies 22 decreases. Here, by arranging the plurality of conductive linear bodies 22 so as to extend in one direction X as shown in Fig. 2, a pressure-sensitive adhesive sheet can be obtained that can uniformly reduce the adhesive strength of the adhesive layer when a voltage is applied to the conductive linear bodies 22.

[0023] In one embodiment of the adhesive sheet of the present invention, from the viewpoint of obtaining an adhesive sheet that can more uniformly reduce the adhesive strength of the adhesive layer when a voltage is applied to the conductive linear elements, it is preferable that the multiple conductive linear elements are linear elements that extend at least from one end of the adhesive structure to the other end, as shown in Figure 2.

[0024] The shape of the conductive linear body when the adhesive structure is viewed in a plane may be linear, or may be a non-linear shape extending in one direction and having a repeating pattern of a predetermined shape such as a sine wave, rectangular wave, triangular wave, sawtooth wave, trapezoidal wave, etc. Furthermore, from the viewpoint of providing a pressure-sensitive adhesive sheet that can more uniformly reduce the adhesive strength of the pressure-sensitive adhesive layer when a voltage is applied to the conductive linear elements, in the pressure-sensitive adhesive sheet of one embodiment of the present invention, when the pressure-sensitive adhesive structure is viewed in plan, the multiple conductive linear elements are preferably arranged so as to be substantially parallel to one another, as shown in Figure 2. In this specification, "substantially parallel to one another" refers to a state in which the angle is less than ±10° from the parallel direction. Furthermore, when the conductive linear elements have a non-linear shape that has a repeating pattern of a predetermined shape and extends in one direction, it is sufficient that the center lines of the multiple non-linear shapes are arranged so as to be substantially parallel to one another.

[0025] Figure 3 is a schematic cross-sectional view of the electrically peelable adhesive sheet 1a shown in Figure 2(a) cut in the thickness direction Z along a straight line Y1-Y2 extending in a direction Y perpendicular to the direction X in which the multiple conductive linear bodies 22 extend. In the cross section in the thickness direction of the adhesive structure of the adhesive sheet of one embodiment of the present invention, the arrangement of the conductive linear members is not particularly limited. 3(a), the plurality of conductive linear bodies 22 may be arranged so as to be present at the interface between the adherend of the pressure-sensitive adhesive layer 21 and the substrate 10 on the side opposite to the surface to which it is attached. In this case, at least a portion of the plurality of conductive linear bodies 22 may be in contact with the substrate 10. Furthermore, as in the adhesive structure 20b shown in Figure 3(b), the multiple conductive linear bodies 22 may be arranged so as to be present inside the adhesive layer 21 without contacting either the surface of the adhesive layer 21 that is attached to the adherend or the boundary surface with the substrate on the opposite side. Furthermore, as in the adhesive structure 20c shown in FIG. 3(c), a plurality of conductive linear members 22 may be arranged on the surface of the adhesive layer 21 that is attached to the adherend.

[0026] In the pressure-sensitive adhesive sheet of one aspect of the present invention, it is preferred that the plurality of conductive linear elements are not exposed on the surface of the pressure-sensitive adhesive layer that is attached to an adherend. With this configuration, the voltage from the conductive linear body 22 can be efficiently applied to the adhesive layer, and the adhesive force can be more effectively reduced.

[0027] From the viewpoint of providing an adhesive sheet that can efficiently apply voltage from the conductive linear body 22 to the adhesive layer and more effectively reduce adhesive strength, it is preferable that the average outer diameter (X2) of the cross section of the adhesive structure of one embodiment of the present invention in the thickness direction is smaller than the thickness (X1) of the adhesive layer. From the above viewpoint, in a cross section in the thickness direction of the adhesive structure of one embodiment of the present invention, the ratio [(X2) / (X1)] of the average outer diameter (X2) of the cross sections of the multiple conductive linear members to the thickness (X1) of the adhesive layer is preferably 0.01 to 0.95, more preferably 0.05 to 0.90, more preferably 0.10 to 0.85, even more preferably 0.15 to 0.80, still more preferably 0.20 to 0.77, even more preferably 0.25 to 0.75, still more preferably 0.30 to 0.73, particularly preferably 0.40 to 0.70, and may further be 0.42 or more, 0.45 or more, 0.47 or more, or 0.50 or more, and may be 0.68 or less, or 0.65 or less.

[0028] In the pressure-sensitive adhesive sheet of one embodiment of the present invention, the thickness (X1) of the pressure-sensitive adhesive layer is preferably 5 to 200 μm, more preferably 10 to 150 μm, even more preferably 15 to 100 μm, still more preferably 20 to 85 μm, and particularly preferably 30 to 70 μm, and may further be 35 μm or more, 40 μm or more, or 45 μm or more, and may be 65 μm or less, 60 μm or less, or 55 μm or less.

[0029] In the pressure-sensitive adhesive sheet of one embodiment of the present invention, the average outer diameter (X2) of the cross section of the conductive linear members is preferably 5 to 75 μm, more preferably 7 to 65 μm, even more preferably 9 to 50 μm, still more preferably 11 to 40 μm, and particularly preferably 12 to 35 μm, and may further be 14 μm or more, 16 μm or more, 18 μm or more, 20 μm or more, 22 μm or more, 24 μm or more, or 26 μm or more, and may be 32 μm or less, or 30 μm or less.

[0030] In this specification, the thickness (X1) of the pressure-sensitive adhesive layer refers to the thickness of the pressure-sensitive adhesive layer measured at a location in the thickness direction where no conductive linear members are present in a cross section of the pressure-sensitive adhesive sheet, and is, for example, the length of "X1" shown in Figure 3(a). In other words, in an adhesive structure in which multiple conductive linear members are not exposed on the surface of the pressure-sensitive adhesive layer that is attached to an adherend, the thickness (X1) of the pressure-sensitive adhesive layer is the same as the thickness of the adhesive structure. The thickness (X1) of the adhesive layer refers to a value measured in accordance with JIS K6783, Z1702, and Z1709, and can be measured, for example, using a constant pressure thickness measuring device (manufactured by Teclock Corporation, product name "PG-02J"). The average outer diameter (X2) of the cross section of the conductive linear body means the average value of five values ​​obtained by measuring the outer diameter of the cross section of five arbitrarily selected conductive linear bodies using a digital microscope.

[0031] In the pressure-sensitive adhesive sheet of one embodiment of the present invention, the average distance between two adjacent conductive linear bodies is preferably 0.01 to 20 mm, more preferably 0.05 to 15 mm, even more preferably 0.10 to 10 mm, still more preferably 0.20 to 5.0 mm, and particularly preferably 0.30 to 2.5 mm, and may further be 0.35 mm or more, 0.40 mm or more, or 0.45 mm or more, or may be 2.0 mm or less, 1.5 mm or less, 1.2 mm or less, 1.0 mm or less, or 0.8 mm or less. When the average spacing of the conductive linear bodies is within the above range, the pressure-sensitive adhesive sheet can have good adhesive strength before voltage application and can reduce the adhesive strength of the pressure-sensitive adhesive layer more evenly after voltage application, and can also suppress the phenomenon of excessive heat generation. In this specification, the "distance between two adjacent conductive linear bodies" refers to the distance between the centers of two adjacent conductive linear bodies in the direction in which the plurality of conductive linear bodies are arranged (for example, direction Y in FIG. 2), and specifically refers to the length "L" shown in FIG. 3(a). In addition, when the conductive linear bodies have a non-linear shape extending in one direction with a predetermined repeated pattern, the "distance between the center lines of adjacent non-linear conductive linear bodies" is the "distance between two adjacent conductive linear bodies." In addition, the "average distance between two adjacent conductive linear bodies" refers to the average value of the distance L measured between five pairs of adjacent conductive linear bodies selected arbitrarily when the adhesive structure is viewed in plan using a digital microscope.

[0032] The electrically peelable pressure-sensitive adhesive composition, which is a material for forming the pressure-sensitive adhesive layer constituting the pressure-sensitive adhesive structure of the pressure-sensitive adhesive sheet of one embodiment of the present invention, and the conductive linear body will be described below.

[0033] <Electrically Peelable Pressure-Sensitive Adhesive Composition> The pressure-sensitive adhesive layer constituting the pressure-sensitive adhesive structure of the pressure-sensitive adhesive sheet of one embodiment of the present invention is formed from an electrically peelable pressure-sensitive adhesive composition. The electrically peelable pressure-sensitive adhesive composition is not particularly limited as long as it can form a pressure-sensitive adhesive layer that has a certain adhesive strength before voltage application but whose adhesive strength can be reduced by voltage application.

[0034] Among these, from the viewpoint of forming a pressure-sensitive adhesive layer that has high adhesive strength before voltage application and whose adhesive strength can be easily reduced by voltage application, a pressure-sensitive adhesive composition comprising a base polymer (A) (hereinafter also referred to as "component (A)") and an ionic compound (B) (hereinafter also referred to as "component (B)") is preferred as the electrically peelable pressure-sensitive adhesive composition used in one embodiment of the present invention. In this specification, for example, "a pressure-sensitive adhesive composition comprising component (A) and component (B)" means that component (A) and component (B) are used as raw materials for the pressure-sensitive adhesive composition. Therefore, for example, when component (B) is an alkali metal salt, this also includes an embodiment in which the alkali metal salt is ionized into a cation and an anion in the pressure-sensitive adhesive composition.

[0035] The pressure-sensitive adhesive composition used in one embodiment of the present invention preferably further contains a crosslinking agent (C), and may contain or incorporate other additives in addition to the components (A) to (C).

[0036] In the pressure-sensitive adhesive composition used in one embodiment of the present invention, from the viewpoint of providing a pressure-sensitive adhesive composition that has high adhesiveness before voltage application and whose adhesiveness can be easily reduced by voltage application, the total amount of component (A) and component (B) blended is preferably 60 to 100 mass%, more preferably 70 to 100 mass%, even more preferably 80 to 100 mass%, still more preferably 90 to 100 mass%, and particularly preferably 95 to 100 mass%, relative to the total amount (100 mass%) of the active ingredients of the pressure-sensitive adhesive composition.

[0037] From the same viewpoint as above, the total blending amount of component (A), component (B) and component (C) is preferably 65 to 100 mass%, more preferably 75 to 100 mass%, even more preferably 85 to 100 mass%, still more preferably 95 to 100 mass%, and particularly preferably 98 to 100 mass%, relative to the total amount (100 mass%) of active ingredients in the pressure-sensitive adhesive composition. Hereinafter, each component contained in the pressure-sensitive adhesive composition used in one embodiment of the present invention will be described.

[0038] <Component (A): Base Polymer> The base polymer (A) used in one embodiment of the present invention may be any polymer having adhesive properties, such as acrylic polymers, urethane polymers, rubber polymers, olefin polymers, silicone polymers, and curable polymers having polymerizable functional groups in these polymers. These base polymers (A) may be used alone or in combination of two or more. Furthermore, the base polymer (A) used in one embodiment of the present invention may be an emulsion type polymer or a non-emulsion type polymer.

[0039] The mass average molecular weight of the base polymer (A) used in one embodiment of the present invention is preferably 10,000 to 2,000,000, more preferably 20,000 to 1,800,000, even more preferably 30,000 to 1,500,000, still more preferably 40,000 to 1,200,000, and particularly preferably 50,000 to 1,000,000, from the viewpoint of obtaining a pressure-sensitive adhesive composition having high adhesiveness before voltage application. In this specification, the mass average molecular weight is a value measured by gel permeation chromatography (GPC) in terms of polystyrene, and specifically, is a value measured based on the method described in the examples.

[0040] Among these, from the viewpoint of obtaining a pressure-sensitive adhesive composition that has high adhesiveness before voltage application and whose adhesiveness can be easily reduced by voltage application, it is preferable that the base polymer (A) used in one embodiment of the present invention contains an acrylic polymer (A1). From the above viewpoints, in the pressure-sensitive adhesive composition used in one embodiment of the present invention, the content of the acrylic polymer (A1) in component (A) is preferably 30 to 100 mass%, more preferably 50 to 100 mass%, more preferably 70 to 100 mass%, even more preferably 80 to 100 mass%, still more preferably 90 to 100 mass%, and particularly preferably 95 to 100 mass%, relative to the total amount (100 mass%) of component (A) contained in the pressure-sensitive adhesive composition.

[0041] The acrylic polymer (A1) used in one embodiment of the present invention includes a polymer having a structural unit (a1) derived from an alkyl(meth)acrylate (hereinafter also referred to as "monomer (a1')"). From the viewpoint of obtaining a pressure-sensitive adhesive composition that has high adhesiveness before voltage application and whose adhesiveness can be easily reduced by voltage application, the acrylic polymer (A1) is preferably a copolymer having, in addition to the structural unit (a1), a structural unit (a2) derived from a functional group-containing monomer (hereinafter also referred to as "monomer (a2')").

[0042] When the acrylic polymer (A1) is a copolymer, the form of the copolymerization is not particularly limited, and it may be any of a random copolymer, a block copolymer, and a graft copolymer. The acrylic polymer (A1) used in one embodiment of the present invention may be used alone or in combination of two or more kinds.

[0043] From the viewpoint of obtaining a pressure-sensitive adhesive composition having high adhesiveness before voltage application, the mass average molecular weight of the acrylic polymer (A1) is preferably 50,000 to 2,000,000, more preferably 100,000 to 1,500,000, even more preferably 200,000 to 1,200,000, still more preferably 300,000 to 1,000,000, and particularly preferably 400,000 to 900,000.

[0044] The acrylic polymer (A1) used in one embodiment of the present invention may be a copolymer having a structural unit (a3) ​​derived from a monomer other than the monomers (a1') and (a2') (hereinafter also referred to as "monomer (a3')").

[0045] In the acrylic polymer (A1) used in one embodiment of the present invention, the content of the structural units (a1) and (a2) may be 55% by mass or more, 60% by mass or more, 65% by mass or more, 70% by mass or more, 75% by mass or more, 80% by mass or more, 85% by mass or more, 90% by mass or more, or 95% by mass or more, relative to the total amount (100% by mass) of the structural units of the acrylic polymer (A1); or may be 100% by mass or less, 99% by mass or less, 95% by mass or less, 90% by mass or less, or 85% by mass or less. The monomers and structural units that constitute the acrylic polymer (A1) will be described below.

[0046] [Monomer (a1'), structural unit (a1)] The alkyl group of the monomer (a1') preferably has 1 to 30 carbon atoms, more preferably 1 to 20 carbon atoms, even more preferably 1 to 16 carbon atoms, still more preferably 1 to 12 carbon atoms, and particularly preferably 4 to 8 carbon atoms. The alkyl group contained in the monomer (a1') may be a linear alkyl group or a branched alkyl group.

[0047] Specific examples of the monomer (a1′) include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate (n-propyl (meth)acrylate, i-propyl (meth)acrylate), butyl (meth)acrylate (n-butyl (meth)acrylate, i-butyl (meth)acrylate, s-butyl (meth)acrylate, t-butyl (meth)acrylate), pentyl (meth)acrylate, hexyl (meth)acrylate, heptyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, octyl (meth)acrylate, nonyl (meth)acrylate, decyl (meth)acrylate, tridecyl (meth)acrylate, and stearyl (meth)acrylate. These monomers (a1') may be used alone or in combination of two or more. Among these, the monomer (a1') is preferably at least one selected from butyl (meth)acrylate, pentyl (meth)acrylate, hexyl (meth)acrylate, heptyl (meth)acrylate, and 2-ethylhexyl (meth)acrylate, more preferably butyl (meth)acrylate or 2-ethylhexyl (meth)acrylate, and even more preferably butyl (meth)acrylate.

[0048] In the acrylic polymer (A1) used in one embodiment of the present invention, the content of the structural unit (a1) relative to the total amount (100% by mass) of the structural units of the acrylic polymer (A1) is, from the viewpoint of obtaining a pressure-sensitive adhesive composition that improves the adhesiveness before voltage application, ensures the content of the structural unit (a2) described above, and can further improve the cohesive strength, preferably 30% by mass or more, more preferably 40% by mass or more, even more preferably 50% by mass or more, still more preferably 60% by mass or more, and particularly preferably 70% by mass or more; and is also preferably 99.99% by mass or less, more preferably 99.90% by mass or less, even more preferably 99.0% by mass or less, still more preferably 97.0% by mass or less, particularly preferably 95.0% by mass or less, and may even be 90.0% by mass or less, or 85% by mass or less.

[0049] [Monomer (a2'), structural unit (a2)] Examples of the monomer (a2') include hydroxy group-containing monomers, carboxy group-containing monomers, and epoxy group-containing monomers. These monomers (a2') may be used alone or in combination of two or more.

[0050] Examples of hydroxy-containing monomers include hydroxyalkyl (meth)acrylates such as 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 3-hydroxybutyl (meth)acrylate, and 4-hydroxybutyl (meth)acrylate; and unsaturated alcohols such as vinyl alcohol and allyl alcohol. The number of carbon atoms in the alkyl group of the hydroxyalkyl (meth)acrylates is preferably 1 to 10, more preferably 1 to 8, even more preferably 1 to 6, and still more preferably 2 to 4, and the alkyl group may be a linear alkyl group or a branched alkyl group.

[0051] Examples of carboxy group-containing monomers include ethylenically unsaturated monocarboxylic acids such as (meth)acrylic acid and crotonic acid; ethylenically unsaturated dicarboxylic acids such as fumaric acid, itaconic acid, maleic acid and citraconic acid; and 2-carboxylethyl (meth)acrylate.

[0052] Examples of epoxy-containing monomers include epoxy group-containing (meth)acrylic acid esters such as glycidyl (meth)acrylate, β-methylglycidyl (meth)acrylate, (3,4-epoxycyclohexyl)methyl (meth)acrylate, and 3-epoxycyclo-2-hydroxypropyl (meth)acrylate; glycidyl crotonate, and allyl glycidyl ether.

[0053] Among these, the acrylic polymer (A1) used in one embodiment of the present invention is preferably a copolymer having, as the structural unit (a2), a structural unit (a2-1) derived from a carboxy group-containing monomer.

[0054] From the above viewpoints, the content of the structural unit (a2-1) in the acrylic polymer (A1) used in one embodiment of the present invention is preferably 60 to 100 mass%, more preferably 70 to 100 mass%, even more preferably 80 to 100 mass%, still more preferably 90 to 100 mass%, and particularly preferably 95 to 100 mass%, relative to the total amount (100 mass%) of the structural units (a2) contained in the acrylic polymer (A1).

[0055] In the acrylic polymer (A1) used in one embodiment of the present invention, the content of the structural unit (a2) relative to the total amount (100% by mass) of the structural units of the acrylic polymer (A1) is, from the viewpoint of further improving cohesive strength while ensuring the content of the structural unit (a1) and producing a pressure-sensitive adhesive composition with better adhesiveness before voltage application, preferably 0.01% by mass or more, more preferably 0.10% by mass or more, even more preferably 1.0% by mass or more, still more preferably 3.0% by mass or more, particularly preferably 5.0% by mass or more, and may even be 10.0% by mass or more or 15% by mass or more, and is also preferably 60% by mass or less, more preferably 50% by mass or less, even more preferably 40% by mass or less, still more preferably 30% by mass or less, and particularly preferably 20% by mass or less.

[0056] [Monomer (a3'), structural unit (a3)] The monomer (a3') other than the monomers (a1') and (a2') is not particularly limited, and examples thereof include olefins such as ethylene, propylene, and isobutylene; halogenated olefins such as vinyl chloride and vinylidene chloride; diene monomers such as butadiene, isoprene, and chloroprene; styrene, α-methylstyrene, vinyltoluene, vinyl formate, vinyl acetate, acrylonitrile, (meth)acrylamide, (meth)acrylonitrile, (meth)acryloylmorpholine, and N-vinylpyrrolidone. These monomers (a3') may be used alone or in combination of two or more.

[0057] In the acrylic polymer (A1) used in one embodiment of the present invention, the content of the structural unit (a3) ​​may be 0% by mass or more, 1% by mass or more, 5% by mass or more, 10% by mass or more, or 15% by mass, relative to the total amount (100% by mass) of structural units in the acrylic polymer (A1), or may be 45% by mass or less, 40% by mass or less, 35% by mass or less, 30% by mass or less, 25% by mass or less, 20% by mass or less, 15% by mass or less, 10% by mass or less, or 5% by mass or less.

[0058] In the pressure-sensitive adhesive composition used in one embodiment of the present invention, from the viewpoint of providing a pressure-sensitive adhesive composition that has high adhesiveness before voltage application and whose adhesiveness can be easily reduced by voltage application, the amount (content) of component (A) is preferably 25 to 97 mass%, more preferably 30 to 95 mass%, even more preferably 40 to 93 mass%, still more preferably 50 to 90 mass%, and particularly preferably 60 to 87 mass%, relative to the total amount (100 mass%) of the active ingredients of the pressure-sensitive adhesive composition.

[0059] <Component (B): Ionic compound> Examples of the ionic compound (B) used in one embodiment of the present invention include one or more compounds selected from alkali metal salts (B1), organic quaternary ammonium salts (B2), and ionic liquids (B3).

[0060] Among these, the component (B) used in one embodiment of the present invention preferably contains at least one selected from the alkali metal salt (B1) and the ionic liquid (B3). Furthermore, the component (B) used in one embodiment of the present invention preferably uses an alkali metal salt (B1) or an ionic liquid (B3) as a main component. In this specification, the term "main component" refers to the component that is contained in the greatest amount among the components that make up component (B).

[0061] When the main component of component (B) is alkali metal salt (B1), the content of components (B) other than alkali metal salt (B1) may be less than 100 parts by mass, 0 to 90 parts by mass, 0 to 50 parts by mass, 0 to 30 parts by mass, 0 to 20 parts by mass, 0 to 10 parts by mass, 0 to 5 parts by mass, 0 to 1 part by mass, 0 to 0.1 parts by mass, 0 to 0.01 parts by mass, 0 to 0.001 parts by mass, or 0 to 0.0001 parts by mass, relative to 100 parts by mass of the total amount of alkali metal salt (B1).

[0062] When the main component of component (B) is ionic liquid (B3), the content of components (B) other than ionic liquid (B3) may be less than 100 parts by mass, 0 to 90 parts by mass, 0 to 50 parts by mass, 0 to 30 parts by mass, 0 to 20 parts by mass, 0 to 10 parts by mass, 0 to 5 parts by mass, 0 to 1 part by mass, 0 to 0.1 parts by mass, 0 to 0.01 parts by mass, 0 to 0.001 parts by mass, or 0 to 0.0001 parts by mass, relative to 100 parts by mass of the total amount of ionic liquid (B3).

[0063] In the pressure-sensitive adhesive composition used in the present invention, the blending ratio of component (B) relative to a total amount of 100 parts by mass of component (A) is preferably 3 parts by mass or more, more preferably 5 parts by mass or more, more preferably 10 parts by mass or more, even more preferably 13 parts by mass or more, even more preferably more than 15 parts by mass, still more preferably 16 parts by mass or more, and particularly preferably 18 parts by mass or more, from the viewpoint of obtaining a pressure-sensitive adhesive composition whose adhesiveness can be easily reduced by applying a voltage. Furthermore, from the viewpoint of obtaining a pressure-sensitive adhesive composition having high adhesiveness before voltage application, in the pressure-sensitive adhesive composition used in one embodiment of the present invention, the blending ratio of component (B) relative to 100 parts by mass of the total amount of component (A) is preferably 200 parts by mass or less, more preferably 180 parts by mass or less, even more preferably 160 parts by mass or less, even more preferably 150 parts by mass or less, still more preferably 130 parts by mass or less, particularly preferably 120 parts by mass or less, and may even be 100 parts by mass or less, 90 parts by mass or less, 80 parts by mass or less, 70 parts by mass or less, 60 parts by mass or less, 50 parts by mass or less, 45 parts by mass or less, 40 parts by mass or less, 35 parts by mass or less, or 30 parts by mass or less.

[0064] <Component (B1): Alkali metal salt> The alkali metal salt (B1) used in one embodiment of the present invention may be a compound that is solid at room temperature (25° C.) but dissociates into a cation (alkali metal ion) and an anion in a liquid. Specific examples of the alkali metal salt (B1) include MCl, MBr, MI, MAlCl, MAlCl, MBF, MPF, MSCN, MClO, MNO, CHCOOM, and CH. 19 COOM, CF3COOM, C3F7COOM, MCH3SO3, MCF3SO3, MC4F9SO3, MC2H5OSO3, MC6H 13 OSO3, MC8H 17 Examples of suitable fluorine-containing compounds include OSO3, M(CF3SO2)2N, M(C2F5SO2)2N, M(C3F7SO2)2N, M(C4F9SO2)2N, M(CF3SO2)3C, MAsF6, MSbF6, MNbF6, MTaF6, M(CN)2N, M(CF3SO2)(CF3CO)N, M(CH3)2PO4, M(C2H5)2PO4, MCH3(OC2H4)2OSO3, MC6H4(CH3)SO3, M(C2F5)3PF3, CH3CH(OH)COOM, and M(FSO2)2N (wherein M is an alkali metal atom). M is preferably Li, Na, or K, more preferably Na or K, and even more preferably Na. These alkali metal salts (B1) may be used alone or in combination of two or more.

[0065] Among these, the alkali metal salt (B1) used as component (B) in one embodiment of the present invention preferably contains an alkali metal salt (B11) represented by the following general formula (b-1). [ka]

[0066] In the above formula (b-1), R Fare each independently a fluorine atom or a fluorinated alkyl group. The number of carbon atoms in the fluorinated alkyl group is preferably 1 to 10, more preferably 1 to 8, even more preferably 1 to 4, still more preferably 1 to 3, and particularly preferably 1 to 2. In this specification, the term "fluorinated alkyl group" refers to a group in which at least one hydrogen atom in an alkyl group has been substituted with a fluorine atom, and may be either a straight chain or a branched chain. Among the fluorinated alkyl groups, perfluoroalkyl groups in which all hydrogen atoms of the alkyl group have been substituted with fluorine atoms are preferred. The preferred range of the number of carbon atoms in the perfluoroalkyl group is the same as the preferred range of the number of carbon atoms in the above-mentioned fluorinated alkyl group. In one aspect of the invention, R F is preferably a fluorine atom or a perfluoroalkyl group, more preferably a fluorine atom, —CF 3 , —C 2 F 5 , —C 3 F 7 , or —C 4 F 9 , and even more preferably a fluorine atom or —CF 3 .

[0067] M is an alkali metal atom (lithium atom (Li), sodium atom (Na), potassium atom (K), rubidium atom (Rb), cesium atom (Cs), or francium atom (Fr)), preferably Li, Na, or K, more preferably Na or K, and even more preferably Na.

[0068] <Component (B2): Organic quaternary ammonium salt> The organic quaternary ammonium salt (B2) used in one embodiment of the present invention may be a compound that is solid at room temperature (25° C.) and is represented by the following general formula (b-2). The organic quaternary ammonium salt (B2) may be used alone or in combination of two or more kinds. [ka]

[0069] In the above general formula (b-2), R 11 ~R 14are each independently an alkyl group having 1 to 4 carbon atoms. X is F, Cl, Br, I, ClO4, BF4, PF6, or [(R 15 )4N]2SO4(R 15 are each independently an alkyl group having 1 to 4 carbon atoms).

[0070] Specific examples of the organic quaternary ammonium salt (B2) include ammonium bromides or ammonium chlorides such as tetrabutyl, tetrapropyl, tetraethyl, tetramethyl, triethylbutyl, triethylpropyl, and triethylmethyl; ammonium tetrafluoroborates such as tetrabutyl, tetrapropyl, tetraethyl, tetramethyl, triethylbutyl, triethylpropyl, and triethylmethyl; ammonium hexafluorophosphates such as tetrabutyl, tetrapropyl, tetraethyl, tetramethyl, triethylbutyl, triethylpropyl, and triethylmethyl; ammonium perchlorates such as tetrabutyl, tetrapropyl, tetraethyl, tetramethyl, triethylbutyl, triethylpropyl, and triethylmethyl; and ammonium sulfates such as tetrabutyl, tetrapropyl, tetraethyl, tetramethyl, triethylbutyl, triethylpropyl, and triethylmethyl.

[0071] <Component (B3): Ionic liquid> The ionic liquid (B3) used in one embodiment of the present invention may be a molten salt that is liquid at room temperature (25° C.) and is a compound composed of an organic cation and an anion that is its counter ion. Examples of organic cations constituting the ionic liquid (B3) include cations represented by any of the following general formulas (b-3-i) to (b-3-viii): Among these, the organic cation constituting the ionic liquid (B3) is preferably the cation represented by the following general formula (b-3-ii): [ka]

[0072] In the above formulas (b-3-i) to (b-3-iv), Ra are each independently an alkyl group having 1 to 20 carbon atoms or an alkenyl group having 1 to 20 carbon atoms. In addition, in the above formulas (b-3-v) to (b-3-viii), R b are each independently a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, or -(C2H4O) n -R c (n is an integer of 1 to 20, R c is an alkyl group having 1 to 20 carbon atoms, or an amino group.

[0073] R a , R b and R c Examples of the alkyl group that can be selected include a methyl group, an ethyl group, a propyl group (n-propyl group, i-propyl group), a butyl group (n-butyl group, i-butyl group, s-butyl group, t-butyl group), a pentyl group (n-pentyl group, i-pentyl group, neopentyl group), a hexyl group, a heptyl group, an octyl group, a 2-ethylhexyl group, a nonyl group, a decyl group, an undecyl group, a dodecyl group, a tridecyl group, a tetradecyl group, a pentadecyl group, a hexadecyl group, a heptadecyl group, and an octadecyl group. The alkyl group may be a straight-chain alkyl group or a branched-chain alkyl group.

[0074] R a and R b Examples of the alkenyl group that can be selected as the above include an ethenyl group (vinyl group), propenyl group, butenyl group, pentenyl group, hexenyl group, heptenyl group, octenyl group, nonenyl group, decenyl group, dodecenyl group, tridecenyl group, tetradecenyl group, pentadecenyl group, hexadecenyl group, and octadecenyl group. The alkenyl group may be a straight-chain alkyl group or a branched-chain alkyl group.

[0075] At least one hydrogen atom bonded to a carbon atom of the cation represented by any one of the general formulae (b-3-i) to (b-3-ii) may be substituted with an alkyl group having 1 to 20 carbon atoms. Specific examples of such alkyl groups are as described above.

[0076] Examples of the cation represented by the general formula (b-3-i) and the cation in which at least one hydrogen atom of the cation has been substituted with the alkyl group include cations represented by any of the following formulae (b-3-i-1) to (b-3-i-11). [ka]

[0077] Examples of the cation represented by general formula (b-3-ii) and the cation in which at least one hydrogen atom of the cation has been substituted with the alkyl group include cations represented by any of the following formulae (b-3-ii-1) to (b-3-ii-26). Cations represented by any of the following formulae (b-3-ii-1) to (b-3-ii-15) are preferred, cations represented by any of the following formulae (b-3-ii-1) to (b-3-ii-3) and (b-3-ii-9) to (b-3-ii-10) are more preferred, cations represented by any of the following formulae (b-3-ii-1) to (b-3-ii-3) are even more preferred, and the cation represented by the following formula (b-3-ii-2) is even more preferred. [ka]

[0078] Examples of the cation represented by the general formula (b-3-iii) include cations represented by any of the following formulae (b-3-iii-1) to (b-3-iii-6). [ka]

[0079] Examples of the cation represented by the general formula (b-3-iv) include cations represented by any of the following formulae (b-3-iv-1) to (b-3-iv-6). [ka]

[0080] Examples of the cation represented by any one of the general formulae (b-3-v) to (b-3-viii) include cations represented by any one of the following formulae: [ka]

[0081] Examples of the anion constituting the ionic liquid (B3) include Cl - , Br - , I - , AlCl4 - , Al2Cl7 - , BF4 - , PF6 - , SCN - , ClO4 - , NO3 - , CH3COO - , CF3COO - , CH3SO3 - , CF3SO3 - , C4F9SO3 - , (CF3SO2)2N - , (C2F5SO2)2N - , (C3F7SO2)2N - , (C4F9SO2)2N - , (CF3SO2)3C - , AsF6 - , SbF6 - , NbF6 - , TaF6 - , (CN)2N - , C4F9SO3 - , (C2F5SO2)2N - , C3F7COO - , (CF3SO2)(CF3CO)N - , C9H 19 COO- , (CH3)2PO4 - , (C2H5)2PO4 - , CH3OSO3 - , C2H5OSO3 - , C4H9OSO3 - , C6H 13 OSO3 - , C8H 17 OSO3 - , CH3(OC2H4)2OSO3 - , C6H4(CH3)SO3 - , (C2F5)3PF3 - , CH3CH(OH)COO - , (FSO2)2N - , B(CN)4 - , C(CN)3 - , N(CN)2 - , p-toluenesulfonate anion, 2-(2-methoxyethyl)ethyl sulfate anion, and the like. Among these, the anion constituting the ionic liquid (B3) used in one embodiment of the present invention is (CF3SO2)2N - or (FSO2)2N - is preferred.

[0082] <Component (C): Crosslinking agent> The pressure-sensitive adhesive composition used in one embodiment of the present invention is preferably further blended with a crosslinking agent (C). By blending the crosslinking agent (C), it becomes easier to prepare a pressure-sensitive adhesive composition that has high adhesiveness before voltage application and whose adhesiveness can be easily reduced by voltage application. The crosslinking agent (C) may be used alone or in combination of two or more kinds.

[0083] Examples of the crosslinking agent (C) used in one embodiment of the present invention include isocyanate-based crosslinking agents, epoxy-based crosslinking agents, imine-based crosslinking agents, and metal chelate-based crosslinking agents.

[0084] Examples of the isocyanate crosslinking agent include tolylene diisocyanate compounds such as 2,4-tolylene diisocyanate and 2,6-tolylene diisocyanate; xylylene diisocyanate compounds such as 1,3-xylylene diisocyanate and 1,4-xylylene diisocyanate; diphenylmethane-4,4'-diisocyanate, diphenylmethane-2,4'-diisocyanate, 3-methyldiphenylmethane diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, dicyclohexylmethane-4,4'-diisocyanate, dicyclohexylmethane-2,4'-diisocyanate, and lysine isocyanate. It is also possible to use trimers of these organic polyisocyanate compounds, as well as isocyanate-terminated urethane prepolymers obtained by reacting these organic polyisocyanate compounds with polyol compounds.

[0085] Examples of epoxy crosslinking agents include bisphenol A type epoxy compounds, bisphenol F type epoxy compounds, 1,3-bis(N,N-diglycidylaminomethyl)toluene, and N,N,N',N'-tetraglycidyl-4,4-diaminodiphenylmethane.

[0086] Examples of imine crosslinking agents include N,N'-diphenylmethane-4,4'-bis(1-aziridinecarboxamide), trimethylolpropane-tri-β-aziridinylpropionate, tetramethylolmethane-tri-β-aziridinylpropionate, and N,N'-toluene-2,4-bis(1-aziridinecarboxamide)triethylenemelamine.

[0087] Examples of metal chelate crosslinking agents include coordination compounds of polyvalent metals, such as aluminum chelate compounds, such as trisethylacetoacetate aluminum, ethylacetoacetate aluminum diisopropylate, and trisacetylacetonate aluminum.

[0088] In the pressure-sensitive adhesive composition used in one embodiment of the present invention, from the viewpoint of facilitating the preparation of a pressure-sensitive adhesive composition that has high adhesiveness before voltage application and whose adhesiveness can be easily reduced by voltage application, the amount of component (C) blended is preferably 0.001 to 10.0 parts by mass, more preferably 0.005 to 7.0 parts by mass, even more preferably 0.010 to 5.0 parts by mass, still more preferably 0.015 to 2.0 parts by mass, and particularly preferably 0.020 to 1.0 part by mass, relative to 100 parts by mass of the total amount of component (A).

[0089] <Other additives> The pressure-sensitive adhesive composition used in one embodiment of the present invention may be blended with or contain additives other than the components (A) to (C). Such other additives are appropriately selected depending on the application of the pressure-sensitive adhesive sheet, and examples include tackifiers, compatibilizers, wetting agents, thickeners, defoamers, antioxidants, ultraviolet absorbers, softeners (plasticizers), fillers, rust inhibitors, pigments, dyes, etc. As these other additives, additives used in general pressure-sensitive adhesive compositions can be used. Each additive may be used alone or in combination of two or more kinds.

[0090] The amount of each of these other additives to be added is set appropriately depending on the type of additive, but is preferably 0.01 to 50 parts by mass, more preferably 0.05 to 40 parts by mass, and even more preferably 0.1 to 30 parts by mass, relative to 100 parts by mass of the total amount of component (A).

[0091] The pressure-sensitive adhesive composition used in one embodiment of the present invention may be further diluted with an organic solvent to form a solution, from the viewpoint of facilitating application to a substrate or the like described below and improving workability. Examples of the organic solvent include methyl ethyl ketone, acetone, ethyl acetate, tetrahydrofuran, dioxane, cyclohexane, n-hexane, toluene, xylene, n-propanol, and isopropanol. These organic solvents may be the same as those used in the synthesis of component (A), or one or more organic solvents other than those used in the synthesis of component (A) may be added.

[0092] <Conductive wire> The conductive linear body used in one embodiment of the present invention may be any linear body having conductivity, and examples thereof include a linear body containing a metal wire (hereinafter also referred to as a "metal wire linear body"), a linear body containing a carbon nanotube (hereinafter also referred to as a "carbon nanotube linear body"), and a linear body in which a thread is coated with a conductive material (hereinafter also referred to as a "conductive material coated linear body").

[0093] Since metal wire linear bodies have high electrical conductivity, high handleability, high thermal conductivity, and versatility, the use of metal wire linear bodies as conductive linear bodies can reduce the resistance value of the adhesive structure. In addition, the cross-sectional diameter of metal wire linear bodies can be easily adjusted to be small.

[0094] The metal wire linear body used as the conductive linear body in one embodiment of the present invention may be a linear body made of a single metal wire, or may be a linear body made of multiple twisted metal wires. Examples of metal wires that constitute the metal wire linear body include wires containing metals such as copper, aluminum, tin-doped indium oxide, tungsten, iron, molybdenum, nickel, titanium, silver, platinum, and gold; and wires containing alloys containing two or more of these metals (for example, steels such as stainless steel and carbon steel, brass, phosphor bronze, zirconium-copper alloy, beryllium copper, iron-nickel, nichrome, nickel-titanium, Kanthal, Hastelloy, and rhenium-tungsten). Among these, from the viewpoint of low volume resistivity, the metal wire is preferably a wire containing at least one selected from tungsten, molybdenum, and an alloy containing these.

[0095] The metal wire linear body used in one embodiment of the present invention may be a linear body in which the surface of the above-mentioned metal wire is further plated with tin, zinc, silver, nickel, chromium, a nickel-chromium alloy, solder, or the like.

[0096] Furthermore, from the viewpoint of making the metallic luster less noticeable and preventing corrosion of the metal wire, the metal wire linear body used in one embodiment of the present invention may be a linear body in which the surface of the above-mentioned metal wire is further coated with a carbon material. Examples of carbon materials that can be used to coat the metal wire include amorphous carbon (such as carbon black, activated carbon, hard carbon, soft carbon, mesoporous carbon, and carbon fiber), graphite, fullerene, graphene, and carbon nanotubes. These carbon materials may be used alone or in combination of two or more.

[0097] An example of a carbon nanotube linear body used as a conductive linear body in one embodiment of the present invention is a linear body (carbon nanowire) obtained by drawing carbon nanotubes into a sheet shape from the end of a carbon nanotube forest, bundling the drawn carbon nanotube sheet, and then twisting the bundle of carbon nanotubes. The carbon nanotube forest is a growth body in which a plurality of carbon nanotubes are grown on a substrate so as to be aligned perpendicular to the substrate, and is sometimes called an "array." In the manufacturing process of the linear body, if no twist is applied during the twisting process, the linear body of carbon nanotubes will be ribbon-shaped, whereas if twist is applied during the twisting process, the linear body of carbon nanotubes will be thread-shaped (wire-shaped).

[0098] The carbon nanotube linear body used in one embodiment of the present invention is preferably a thread-like carbon nanotube linear body from the viewpoint of uniformity of the diameter of the linear body, and is preferably a thread-like carbon nanotube linear body obtained by twisting a carbon nanotube sheet from the viewpoint of high purity.

[0099] Alternatively, linear carbon nanotubes can be obtained by spinning a dispersion of carbon nanotubes. Examples of methods for producing linear carbon nanotubes by spinning include those described in U.S. Patent Application Publication No. 2013 / 0251619 (JP 2012-126635 A).

[0100] The carbon nanotube linear body of the present invention may be a linear body in which a plurality of carbon nanotube linear bodies are woven together, or may be a linear body in which carbon nanotube linear bodies are composited with other conductive materials (hereinafter also referred to as a "composite linear body").

[0101] The composite linear body may take the following forms (1) to (3), for example. (1) A composite linear body in which a metal or metal alloy is supported on the surface of the carbon nanotube forest, sheet, or bundle, or the twisted linear body by vapor deposition, ion plating, sputtering, wet plating, etc., during the process of drawing carbon nanotubes from the end of a carbon nanotube forest into a sheet-like carbon nanotube sheet, bundling these, and then twisting the carbon nanotube bundles to form a carbon nanotube linear body. (2) A composite filamentary body obtained by twisting bundles of carbon nanotubes together with at least one selected from a filamentary body of a simple metal, a filamentary body of a metal alloy, and a composite filamentary body. (3) A composite linear body obtained by braiding at least one selected from a linear body of a simple metal, a linear body of a metal alloy, and a composite linear body with a carbon nanotube linear body or a composite linear body. In the composite linear body of the above embodiment (2), when the bundles of carbon nanotubes are twisted, a metal may be supported on the carbon nanotubes in the same manner as in the composite linear body of the above embodiment (1). The composite linear body of the above embodiment (3) is a composite linear body made by weaving at least two types of linear body, and may be a composite linear body made by weaving three or more types of linear body.

[0102] Examples of the metals and alloys constituting the linear bodies of simple metals and linear bodies of metal alloys used in the above embodiments (1) to (3) include simple metals such as gold, silver, copper, iron, aluminum, nickel, chromium, tin, and zinc, and alloys containing at least one of these simple metals (such as copper-nickel-phosphorus alloys and copper-iron-phosphorus-zinc alloys).

[0103] Examples of the thread that constitutes the conductive material-coated linear body used as the conductive linear body in one embodiment of the present invention include threads spun from resins such as nylon and polyester. Examples of conductive materials that can be used to coat the yarn include metals, conductive polymers, and carbon materials. Coating the yarn with a conductive material can be performed by plating, vapor deposition, or the like. A conductive material-coated linear body can improve the conductivity of the linear body while maintaining the flexibility of the yarn.

[0104] The cross-sectional shape of the conductive linear body used in one aspect of the present invention is not particularly limited, and examples thereof include a polygonal, flat, elliptical, and circular shape. However, from the viewpoint of ease of inclusion in the pressure-sensitive adhesive layer, an elliptical or circular shape is preferred.

[0105] The volume resistivity of the conductive linear body used in one aspect of the present invention is preferably 1.0×10 -9 ~1.0×10 1 Ω·m, more preferably 1.0×10 -8 ~1.0×10 0 Ω·m, more preferably 1.0×10 -7 ~1.0×10 -1 Ω m, and even more preferably 1.0×10 -6 ~1.0×10 -2 When the volume resistivity of the conductive linear body is in the above range, the sheet resistance of the adhesive structure tends to decrease. In this specification, the volume resistivity of the conductive linear body can be measured by the following steps (a) and (b). Step (a): Apply silver paste to both ends of the conductive linear object to be measured, measure the resistance of the 40 mm section between the ends, and calculate the resistance value of the conductive linear object. Step (b): The cross-sectional area of ​​the conductive linear object to be measured (unit: m 2 ) is multiplied by the resistance value obtained in step (a), and the obtained value is divided by the length between the end portions (0.04 m) to calculate the volume resistivity of the conductive linear body.

[0106] <Current collector> The pressure-sensitive adhesive sheet of one embodiment of the present invention preferably includes a current collector electrically connected to the plurality of conductive linear bodies. The current collector is provided to supply current to the plurality of conductive linear bodies. As shown in FIGS. 2(c) and 2(d), the current collector 41 is preferably disposed so as to be electrically connected to one end of each of the plurality of conductive linear bodies 22.

[0107] Examples of materials for forming the current collector include conductive paste (such as silver paste), metal foil, and metal wire. The thickness of the metal foil is preferably 0.1 to 50 μm, more preferably 1 to 40 μm, and even more preferably 2 to 30 μm, from the viewpoints of ease of work when connecting to multiple conductive linear bodies, ease of adjusting the thickness of the adhesive sheet to be thin, and reduction of the step in the current collector forming portion. From the viewpoint of workability when connecting to an external voltage application device, the current collector is preferably a metal wire. The current collector may be made of one metal wire, but preferably has two or more metal wires.

[0108] Examples of metals that can be used to form metal foils and metal wires include copper, aluminum, tin-doped indium oxide, tungsten, iron, molybdenum, nickel, titanium, silver, platinum, and gold, as well as alloys containing two or more metals (e.g., steels such as stainless steel and carbon steel, brass, phosphor bronze, zirconium-copper alloys, beryllium copper, iron-nickel, nichrome, nickel-titanium, Kanthal, Hastelloy, and rhenium-tungsten). Furthermore, the metal foil or metal wire may be one in which the surface of the above metal is further plated with tin, zinc, silver, nickel, chromium, a nickel-chromium alloy, solder, or the like. Among these, from the viewpoint of reducing the volume resistivity of the current collector, the metal constituting the metal foil and metal wire is preferably one or more metals selected from copper, silver, and alloys containing these.

[0109] The width of the current collector in the pressure-sensitive adhesive sheet according to one embodiment of the present invention is preferably 50 to 3000 μm, more preferably 75 to 2000 μm, and even more preferably 100 to 1500 μm. Furthermore, when a portion of the current collector 41 is encapsulated in the adhesive layer 21, as in the adhesive sheet 1c shown in Figure 2(c), it is preferable to adjust the width of the current collector so that it is not exposed on the surface of the adhesive layer 21 that is attached to the adherend. When the current collector is made up of multiple metal wires, the width of the current collector is the sum of the diameters of the individual metal wires. When the current collector is made up of multiple metal wires, the multiple metal wires may be in direct contact with each other or may be electrically connected via a conductive linear body. When the cross-sectional shape of the current collector is circular, the width of the current collector refers to the diameter (longer axis) of the circular cross-section.

[0110] <Base material> In a general electrically releasing pressure-sensitive adhesive sheet, in order to apply a voltage to the pressure-sensitive adhesive layer, it is essentially essential that the substrate is a conductive substrate and the adherend is a metal. For example, when the substrate is a resin film, since the resin film is an electrically insulating material, a voltage cannot be applied to the pressure-sensitive adhesive layer, and the adhesive strength cannot be reduced by applying a voltage. On the other hand, the pressure-sensitive adhesive sheet of one embodiment of the present invention has an adhesive structure including a pressure-sensitive adhesive layer and a plurality of conductive linear members, and a voltage can be applied to the pressure-sensitive adhesive layer via the conductive linear members. Therefore, the substrate of the pressure-sensitive adhesive sheet of one embodiment of the present invention does not need to be a conductive substrate, and a substrate made of an insulating material can also be used. In other words, the pressure-sensitive adhesive sheet of one embodiment of the present invention has a wider range of substrate materials to choose from, allowing a substrate more suitable for the application to be selected.

[0111] Examples of the substrate included in the pressure-sensitive adhesive sheet of one embodiment of the present invention include not only conductive substrates but also paper substrates, resin films, and the like. Examples of materials constituting the conductive substrate include metals such as aluminum, tin-doped indium oxide, copper, iron, silver, platinum, and gold, and alloys of these metals. Alternatively, the conductive substrate may be a metal-deposited body obtained by depositing the above metals on a resin film such as polyethylene terephthalate.

[0112] Examples of paper materials that constitute the paper substrate include thin paper, medium-quality paper, wood-free paper, impregnated paper, coated paper, art paper, parchment paper, and glassine paper.

[0113] Examples of resins that may be used to form the resin film include polyester resins such as polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate; polyolefin resins such as polyethylene and polypropylene; vinyl resins such as polyvinyl chloride, polyvinylidene chloride, polyvinyl alcohol, ethylene-vinyl acetate copolymer, and ethylene-vinyl alcohol copolymer; polystyrene; acrylonitrile-butadiene-styrene copolymer; cellulose triacetate; polycarbonate; urethane resins such as polyurethane and acrylic-modified polyurethane; polymethylpentene; polysulfone; polyether ether ketone; polyether sulfone; polyphenylene sulfide; polyimide resins such as polyetherimide and polyimide; polyamide resins; acrylic resins; and fluorine-based resins.

[0114] These resin films may be made of only one type of resin, or may be made of two or more types of resin. The resin film used in one embodiment of the present invention may contain, in addition to the above-mentioned resin, various additives such as an ultraviolet absorber, a light stabilizer, an antioxidant, an antistatic agent, a slip agent, an antiblocking agent, and a colorant.

[0115] The resin film may be unstretched or may be stretched uniaxially, such as longitudinally or transversely, or biaxially. The resin film may also be a resin film having a void-containing layer containing voids therein, and may be a resin film in which a void-free resin layer is further laminated on at least one surface side of the void-containing layer.

[0116] The substrate used in one embodiment of the present invention may be a single-layer substrate or a multi-layer substrate. Examples of multilayer substrates include laminated resin films formed by laminating two or more types of resin films, and laminate substrates formed by laminating a paper substrate with a thermoplastic resin such as polyethylene.

[0117] When the substrate used in one embodiment of the present invention is a resin film or a laminate substrate, the surface of the substrate may be subjected to a surface treatment such as an oxidation method or a roughening method, or a primer treatment. The oxidation method is not particularly limited, and examples thereof include corona discharge treatment, plasma treatment, chromic acid oxidation (wet), flame treatment, hot air treatment, ozone / ultraviolet irradiation treatment, and the like. The method for forming the irregularities is not particularly limited, and examples thereof include sandblasting and solvent treatment.

[0118] The thickness of the substrate used in one embodiment of the present invention is preferably 5 to 300 μm, more preferably 10 to 150 μm, and even more preferably 20 to 100 μm.

[0119] <Release sheet> The release sheet included in the pressure-sensitive adhesive sheet of the present invention can be obtained by applying a release agent to one or both sides of a substrate for the release sheet. Examples of substrates for release sheets include polyesters such as polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate; resin films such as polyethylene, polypropylene, polybutene, polybutadiene, polymethylpentene, polyvinyl chloride, vinyl chloride copolymers, polyurethane, ethylene-vinyl acetate copolymers, ionomer resins, ethylene (meth)acrylic acid copolymers, polystyrene, polycarbonate, fluororesins, low-density polyethylene, linear low-density polyethylene, and triacetyl cellulose; paper substrates such as fine paper, coated paper, and glassine paper; and laminated paper in which a thermoplastic resin such as polyethylene is laminated onto these paper substrates.

[0120] Examples of the release agent that can be used include silicone resins, olefin resins, long-chain alkyl resins, alkyd resins, fluorine resins, and rubber elastomers such as isoprene resins and butadiene resins.

[0121] The thickness of the release sheet is not particularly limited, but is preferably 5 to 300 μm, more preferably 10 to 200 μm. When a polyethylene terephthalate film is used as the release sheet substrate, the thickness is preferably 10 to 100 μm.

[0122] [Method for producing electrically releasable adhesive sheet] The method for producing the pressure-sensitive adhesive sheet of one embodiment of the present invention is not particularly limited, and examples thereof include the following method (1) or (2). Method (1): A manufacturing method in which an adhesive composition is applied to a substrate or a release sheet to form an adhesive layer, and then a conductive linear element is placed on the surface of the adhesive layer. Method (2): A method of manufacturing by placing a conductive linear body on a substrate or a release sheet, and then applying an adhesive composition thereon to form an adhesive layer.

[0123] In the methods (1) and (2), the pressure-sensitive adhesive composition can be applied to the substrate or release sheet by a known application method, such as spin coating, spray coating, bar coating, knife coating, roll coating, blade coating, die coating, or gravure coating. In addition, from the viewpoint of improving the coatability onto a substrate or a release sheet, the pressure-sensitive adhesive composition used in one embodiment of the present invention is preferably diluted with an organic solvent and used in the form of a solution.

[0124] When a crosslinking agent is blended into the adhesive composition used to form the adhesive layer, it is preferable to carry out a seasoning step in which the composition is held for a certain period of time (for example, about 1 to 14 days) to complete the crosslinking.

[0125] As a method for arranging the conductive linear bodies, a method may be mentioned in which the conductive linear bodies are placed on the surface of the pressure-sensitive adhesive layer formed as described above, and then a substrate or a release sheet is laminated on the conductive linear bodies by applying a certain pressure, so that the conductive linear bodies are enclosed within the pressure-sensitive adhesive layer. Alternatively, a method may be used in which a conductive linear body is placed on a substrate or a release sheet before the pressure-sensitive adhesive layer is formed, and a pressure-sensitive adhesive composition is applied thereon to form a pressure-sensitive adhesive layer, thereby encapsulating the conductive linear body within the pressure-sensitive adhesive layer.

[0126] Alternatively, the conductive linear bodies can be arranged through the following steps (I) to (IV). Step (I): A substrate or a release sheet having an adhesive layer formed thereon is wound around and fixed to the side of a drum member so that the adhesive surface of the adhesive layer faces outward. Step (II): While rotating the drum member, the conductive linear body is wound spirally onto the adhesive surface of the adhesive layer. Step (III): The bundle of spirally wound conductive linear bodies 22 is cut along the axial direction of the drum member.

[0127] By electrically connecting a current collector to the end of the conductive linear body arranged in this manner by a known method, it is possible to obtain a pressure-sensitive adhesive sheet with a current collector.

[0128] [Physical properties of adhesive sheet] The pressure-sensitive adhesive sheet of one embodiment of the present invention has high adhesive strength before voltage application, but the adhesive strength can be easily reduced by voltage application. In the pressure-sensitive adhesive sheet of one embodiment of the present invention, the adhesive strength before voltage application is preferably 7.5 N / 25 mm or more, more preferably 8.0 N / 25 mm or more, even more preferably 8.5 N / 25 mm or more, still more preferably 9.0 N / 25 mm or more, and particularly preferably 11.0 N / 25 mm or more.

[0129] Furthermore, when a pressure-sensitive adhesive sheet according to one embodiment of the present invention is attached to an adherend and a voltage of 10 V is applied for 60 seconds, the following formula (i) is obtained before and after the voltage application. Formula (i): [Adhesive strength reduction rate (%)] = 100 - [Adhesive strength of test sheet after voltage application] / [Adhesive strength of test sheet before voltage application] × 100 The adhesive strength reduction rate calculated from is preferably 30% or more, more preferably 35% or more, more preferably 40% or more, even more preferably 45% or more, still more preferably 50% or more, and particularly preferably 55% or more. In this specification, the method for measuring the adhesive strength of the adhesive sheet before and after voltage application is based on the method described in the Examples below.

[0130] [Method of using the electrically releasable adhesive sheet] The pressure-sensitive adhesive sheet of one embodiment of the present invention is preferably used by being attached to an adherend made of a conductive material. Examples of conductive materials constituting the adherend include metals such as aluminum, tin-doped indium oxide, copper, iron, silver, platinum, and gold, and alloys of these metals. These conductive materials may be used alone or in combination of two or more.

[0131] The present invention also provides a method of use described in [i] below. [i] A method for using an electrically peelable adhesive sheet, comprising applying an electrically peelable adhesive sheet according to one embodiment of the present invention to an adherend made of a conductive material, and then peeling the sheet from the adherend by applying a voltage to the plurality of conductive linear elements. In the method of use described in [i] above, after the electrically peelable adhesive sheet has been attached to an electrically conductive adherend, when it is desired to peel the adhesive sheet, the adhesive sheet can be peeled from the adherend by applying a voltage to the adhesive layer.

[0132] Fig. 4 is a schematic perspective view showing an example of a method of using the electrically peelable adhesive sheet of one embodiment of the present invention. In Fig. 4, an example of the method of use is shown using the adhesive sheet 1d shown in Fig. 2(d), but the same can be used with adhesive sheets having configurations other than adhesive sheet 1d. 4(a) shows a state in which the anode terminal 51 of the voltage application device 50 is connected to the current collector 41, and the cathode terminal 52 is connected to the conductive adherend 100. Note that the anode terminal may be connected to the conductive adherend 100, and the cathode terminal 52 may be connected to the current collector 41, inversely to FIG. By connecting as shown in FIG. 4(a), when a voltage is applied, a current can be passed in the thickness direction of the adhesive layer of the adhesive structure, which can reduce the adhesive strength.

[0133] When a voltage is applied in the state shown in Fig. 4(a), as shown in Fig. 4(b), the adhesive force between the adhesive surface of the adhesive structure 20 and the attached conductive adherend 100 decreases, and the adhesive sheet 1d can be easily peeled off from the conductive adherend 100. When peeling the adhesive sheet 1d from the conductive adherend 100, it is preferable to peel it off along one direction in which the conductive linear bodies extend. The voltage to be applied (applied voltage) is preferably 1 to 200 V, more preferably 3 to 140 V, and even more preferably 6 to 120 V, and the time for which a voltage in this range is applied (application time) is preferably 1 to 180 seconds, more preferably 5 to 120 seconds, and even more preferably 10 to 90 seconds. [Example]

[0134] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to the following examples. The physical properties were measured by the following methods.

[0135] [Mass average molecular weight (Mw)] Measurement was carried out using a gel permeation chromatograph (manufactured by Tosoh Corporation, product name "HLC-8020") under the conditions below, and the values ​​measured were converted into standard polystyrene equivalents. (Measurement conditions) Column: "TSK guard column HXL-L", "TSK gel G2500HXL", "TSK gel G2000HXL" and "TSK gel G1000HXL" connected in sequence (all manufactured by Tosoh Corporation) Column temperature: 40℃ Developing solvent: tetrahydrofuran ·Flow rate: 1.0mL / min

[0136] [Volume resistivity of conductive linear body] The measurements were carried out through the following steps (a) and (b). Step (a): Apply silver paste to both ends of the conductive linear object to be measured, measure the resistance of the 40 mm section between the ends, and calculate the resistance value of the conductive linear object. Step (b): The cross-sectional area of ​​the conductive linear object to be measured (unit: m 2 ) is multiplied by the resistance value obtained in step (a), and the obtained value is divided by the length between the end portions (0.04 m) to calculate the volume resistivity of the conductive linear body.

[0137] Manufacturing Example 1 Each component was added in the type and amount shown in Table 1, and diluted with ethyl acetate as a dilution solvent to prepare an electrically peelable pressure-sensitive adhesive composition a. Details of each component used in preparing composition a are as follows. <Base polymer> "Acrylic copolymer (1)": a copolymer having structural units derived from n-butyl acrylate (BA) and acrylic acid (AA) (structural unit ratio: BA / AA = 90 / 10 (mass ratio)), Mw = 470,000. <Ionic compounds> "NaFSI": sodium bis(fluorosulfonyl)imide (R in the general formula (b-1) F is an alkali metal salt where M is a fluorine atom and M is a sodium atom), and is solid at room temperature (25°C). <Crosslinking agent> "E-AX": Manufactured by Soken Chemical & Engineering Co., Ltd., product name "E-AX", epoxy crosslinking agent.

[0138] [Table 1]

[0139] Examples 1 and 2 (1) Formation of adhesive layer An electrically peelable pressure-sensitive adhesive composition a shown in Table 2 was applied to the release-treated surface of a release sheet (manufactured by Lintec Corporation, product name "SP-PET381031", thickness: 38 μm, polyethylene terephthalate (PET) film with a silicone release-treated surface) to form a coating film with a dry thickness of 50 μm. The coating film was then dried at 100°C for 2 minutes to form a pressure-sensitive adhesive layer on the release sheet. (2) Preparation of adhesive sheet The release sheet having the adhesive layer formed as described above was wrapped around and fixed to the side of a drum member having an outer peripheral surface made of rubber, without wrinkles, with the adhesive surface of the adhesive layer facing outwards. Then, the conductive linear body shown in Table 2 wound around a bobbin was attached to the surface of the adhesive layer of the release sheet located near the end of the drum member, and the conductive linear body was unwound and wound around the drum member. The drum member was gradually moved in a direction parallel to the drum axis until the conductive linear body was attached to the surface of the adhesive layer while drawing a spiral at intervals shown in Table 2 and winding around the drum member. The drum member was then removed from the release sheet, and an adhesive structure was formed on the release sheet. One end of the adhesive structure had multiple conductive linear bodies exposed that were not encapsulated in the adhesive layer. A gold-plated copper wire (diameter 150 μm, manufactured by Tokusai Corporation, product name "C1100-H AuP") serving as a current collector was attached so as to be electrically connected in a direction perpendicular to the extension direction of the conductive linear body. Next, a polyethylene terephthalate (PET) film (manufactured by Toyobo Co., Ltd., product name "Cosmoshine A4300", thickness 50 μm) was laminated onto the surface of the adhesive layer to which the conductive linear bodies were attached, and after seasoning for 168 hours in an environment of 23°C and 50% RH (relative humidity), an adhesive sheet having the same laminate structure as adhesive sheet 3 in Figure 1(c) and a current collector as shown in adhesive sheet 1d in Figure 2(d) was produced. Furthermore, when the release sheet of the pressure-sensitive adhesive sheet was removed and the adhesive surface on the side to be attached to the adherend was observed, no exposed conductive linear members were confirmed. Furthermore, a cross section of the pressure-sensitive adhesive sheet after the release sheet was removed, cut in the thickness direction Z in the direction Y perpendicular to the direction X in which the conductive linear members extend, showed that multiple conductive linear members were arranged on the boundary surface side with the substrate, as shown in Figure 3(a).

[0140] The adhesive strength of the prepared adhesive sheet was measured before and after application of electric power according to the following method, and the rate of decrease in adhesive strength was calculated. The results are shown in Table 2.

[0141] [Adhesive strength of test sheet before voltage application] The prepared PSA sheet was cut to a size of 25 mm x 75 mm so that the current collector was included, to prepare a test sheet with a current collector. The release sheet of the test sheet was removed in an environment of 23°C and 50% RH (relative humidity), and the exposed adhesive surface of the PSA layer was attached to a conductive adherend: an aluminum plate (manufactured by Paltec Co., Ltd., product name "A105OP," cut into a size of 75 mm x 70 mm x 1 mm). For attachment, a 2 kg roller was used, moving back and forth once to press the sheet against the adherend, and the sheet was left for 30 minutes in an environment of 23°C and 50% RH (relative humidity). The adhesive strength of the test sheet before voltage application was measured when the test sheet was peeled from the substrate using a tensile testing machine (manufactured by Orientec, product name "Tensilon") at a peel speed of 300 mm / min and a peel angle of 180° under conditions of 23°C and 50% RH (relative humidity). The value (unit: N / 25 mm) was used as the adhesive strength of the test sheet before voltage application.

[0142] [Adhesive strength of test sheet after voltage application] As described above, the test sheet was attached to an aluminum plate, which was a conductive adherend, and then, as shown in Fig. 4(a), the anode terminal 51 of a voltage application device 50 (manufactured by Takasago Machinery Works, Ltd., product name "KH-100H") was connected to the current collector 41, and the cathode terminal 52 was connected to the aluminum plate, which was a conductive adherend 100. In this state, a voltage of 10 V was applied for 60 seconds. After applying the voltage, the test sheet was left to stand for 60 seconds, and then, under conditions of 23°C and 50% RH (relative humidity), a tensile testing machine (manufactured by Orientec Co., Ltd., product name "Tensilon") was used to peel the test sheet from the conductive adherend at a peel rate of 300 mm / min and a peel angle of 180°, as shown in Figure 4(b). The measured value (unit: N / 25 mm) was used as the adhesive strength of the test sheet after applying the voltage.

[0143] [Calculation of adhesive strength reduction rate] Based on the adhesive strength values ​​of the test sheet measured as described above before and after voltage application, the adhesive strength reduction rate was calculated using the following formula. · [Adhesive strength reduction rate (%)] = 100 - [Adhesive strength of test sheet after voltage application] / [Adhesive strength of test sheet before voltage application] × 100 When the adhesive strength reduction rate is a negative value, it indicates that the adhesive strength has increased due to the application of voltage.

[0144] [Table 2]

[0145] Table 2 shows that the pressure-sensitive adhesive sheets produced in Examples 1 and 2 had high adhesiveness before voltage application, but the adhesive strength could be reduced by voltage application. [Explanation of symbols]

[0146] 1, 2, 3, 4, 1a, 1b, 1c, 1d, Electrically peelable adhesive sheet 10 Base material 20, 20' adhesive structure 21 adhesive layer 22 Conductive wire 30 Peel-off sheet 41 Current collector 50 Voltage application device 51 Anode terminal 52 cathode terminal 100 Conductive adherend

Claims

1. An electrically peelable adhesive sheet having an adhesive structure including an adhesive layer formed from an electrically peelable adhesive composition and a plurality of conductive linear members, wherein the plurality of conductive linear members are not exposed on the surface of the adhesive layer that is attached to an adherend.

2. The electrically peelable adhesive sheet according to claim 1 , wherein the adhesive structure has a structure in which the adhesive layer encloses at least a portion of the plurality of conductive linear bodies extending in one direction.

3. 3. The electrically peelable adhesive sheet according to claim 1, wherein in a cross section of the adhesive structure in the thickness direction, the average outer diameter (X2) of the cross section of the plurality of conductive linear bodies is smaller than the thickness (X1) of the adhesive layer.

4. 4. The electrically peelable adhesive sheet according to claim 1, wherein, in a cross section of the adhesive structure in the thickness direction, the ratio [(X2) / (X1)] of the average outer diameter (X2) of the cross section of the plurality of conductive linear bodies to the thickness (X1) of the adhesive layer is 0.01 to 0.

95.

5. The electrically peelable pressure-sensitive adhesive sheet according to any one of claims 1 to 4, wherein the pressure-sensitive adhesive layer has a thickness (X1) of 5 to 200 µm.

6. The electrically peelable adhesive sheet according to any one of claims 1 to 5, wherein the plurality of conductive linear members are arranged so as to be approximately parallel to one another when the adhesive structure is viewed in a plan view.

7. The volume resistivity of the conductive linear body is 1.0×10 －９ ~1.0 x 10 １ The electrically peelable pressure-sensitive adhesive sheet according to any one of claims 1 to 6, having a resistance of Ω·m.

8. The electrically peelable pressure-sensitive adhesive sheet according to any one of claims 1 to 7, having the adhesive structure on at least one surface side of a substrate.

9. The electrically peelable pressure-sensitive adhesive sheet according to any one of claims 1 to 8, further comprising a current collector electrically connected to the plurality of conductive linear members.

10. The electrically peelable pressure-sensitive adhesive sheet according to any one of claims 1 to 9, which is used by being attached to an adherend made of a conductive material.

11. A method for using an electrically peelable pressure-sensitive adhesive sheet, comprising: attaching the electrically peelable pressure-sensitive adhesive sheet according to any one of claims 1 to 10 to an adherend made of a conductive material, and then applying a voltage to the plurality of conductive linear bodies to peel the sheet from the adherend.

Images