Pressure sensitive adhesive tape, article, and method of dismantling article

Abstract

To provide a pressure sensitive adhesive tape that can be easily heated and peeled off in a short time, can prevent thermal damage to an adherend, and enables heating and peeling operation to be easily performed, an article in which at least two adherends are bonded via the pressure sensitive adhesive tape, and a method of dismantling the article.SOLUTION: A pressure sensitive adhesive tape including at least a pressure sensitive adhesive layer, a heat-generating element, and a melt-softening layer adjacent to the heat-generating element in this order is provided. The melt-softening layer contains a thermoplastic resin and an inorganic hollow filler.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to an adhesive tape that can be used in various fields such as the manufacture of electronic devices, an article having a structure bonded by the adhesive tape, and a method for dismantling the article. [Background technology]

[0002] Adhesive tapes are used as a joining means with excellent workability and high adhesive reliability for fixing parts in various industrial fields such as office automation equipment, IT products, home appliances, and automobiles, temporarily fixing parts, and labeling to display product information. In recent years, from the viewpoint of protecting the global environment, there has been an increasing demand for recycling and reusing used products in various industrial fields such as home appliances and automobiles. When recycling and reusing various products, it is necessary to peel off the adhesive tape used to fix parts or for labels, but since the adhesive tape is provided in various places in the product, there is a demand for reducing the work cost by a simple removal process.

[0003] In order to separate adherends from each other, for example, a hot melt adhesive composition that dissolves quickly in a short time by electromagnetic induction heating has been proposed (see, for example, Patent Document 1). As a method for separating adherends from each other, a method for dismantling a building has been proposed in which a metal base material is heated by an electromagnetic induction heating device, the adhesive between the base material and the interior material is heated and foamed to separate it, and the interior material is peeled off from the metal base material (see, for example, Patent Document 2). In addition, a double-sided adhesive tape having a thermally conductive layer that can be easily dismantled by contacting it with a heat source and directly heating the thermally conductive layer has been proposed (see, for example, Patent Document 3). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2002-188068 A [Patent Document 2] JP 2006-200279 A [Patent Document 3] JP 2016-108394 A Summary of the Invention [Problem to be solved by the invention]

[0005] However, in the conventional method of peeling and dismantling by heating, heat is applied from the outside, so if an attempt is made to generate the amount of heat required for peeling the adhesive tape from a heating element, the generated heat may cause thermal degradation or thermal damage to the adherend. On the other hand, if an attempt is made to suppress the thermal degradation or thermal damage of the adherend, the amount of heat generated may decrease, and the adhesive tape may not be heated sufficiently, making peeling difficult. Therefore, there is a demand for adhesive tapes that fix adherends such as rigid bodies together, and that have the function of allowing the adherend parts to be dismantled and reused, and in particular, there is a demand for adhesive tapes that have the function of being easily dismantled and peeled by heating.

[0006] An object of the present invention is to provide an adhesive tape which can be peeled off by heating in a short time, which can prevent thermal damage to an adherend, and which is easy to peel off by heating, an article having a structure bonded by the adhesive tape, and a method for dismantling the article. [Means for solving the problem]

[0007] The present invention relates to the following (1) to (18). (1) An adhesive tape comprising, at least in this order, an adhesive layer, a heating element, and a melt-softening layer adjacent to the heating element, the melt-softening layer containing a thermoplastic resin and an inorganic hollow filler. (2) The pressure-sensitive adhesive tape according to (1), wherein the thermoplastic resin constituting the melt-softening layer comprises a block copolymer or a hydrogenated product thereof, the block copolymer comprising a polymer block containing a structural unit derived from an aromatic vinyl compound and a polymer block containing a structural unit derived from a conjugated diene compound. (3) The pressure-sensitive adhesive tape according to (1) or (2), wherein the blending amount of the inorganic hollow filler in the melt-softening layer is in the range of 5 to 80 volume %. (4) The pressure-sensitive adhesive tape according to any one of (1) to (3), wherein the inorganic hollow filler has an average particle size in the range of 1 to 200 μm. (5) The pressure-sensitive adhesive tape according to any one of (1) to (4), wherein the inorganic hollow filler is at least one selected from the group consisting of a glass hollow filler and a silica hollow filler. (6) The pressure-sensitive adhesive tape according to any one of (1) to (5), wherein the melt-softenable layer has a thickness in the range of 10 to 200 μm. (7) The pressure-sensitive adhesive tape according to any one of (1) to (6), wherein the melt-softened layer has a thermal conductivity in the range of 0.03 to 0.20 W / m·K. (8) The pressure-sensitive adhesive tape according to any one of (1) to (7), wherein a temperature range in which a loss tangent (tan δ) of a component other than the inorganic hollow filler that contains the thermoplastic resin and that constitutes the melt-softening layer is 0.8 or more is 80° C. or higher. (9) The pressure-sensitive adhesive tape according to any one of (1) to (8), wherein the temperature at which the pressure-sensitive adhesive layer has a loss tangent (tan δ) of 0.8 or more is higher than the temperature at which a component constituting the melt-softening layer, other than the inorganic hollow filler and containing the thermoplastic resin, has a loss tangent (tan δ) of 0.8 or more. (10) The pressure-sensitive adhesive tape according to any one of (1) to (9), wherein the heating element has a volume resistivity of 30 μΩ·cm or more at 20° C. (11) The pressure-sensitive adhesive tape according to any one of (1) to (10), wherein the heating element has a pair of extending portions extending from outer peripheries of the pressure-sensitive adhesive layer and the melt-softening layer in a plan view. (12) The pressure-sensitive adhesive tape according to any one of (1) to (11), further comprising an adhesive layer on the surface of the melt-softening layer opposite to the surface adjacent to the heating element. (13) The pressure-sensitive adhesive tape according to any one of (1) to (12), wherein the melt-softening layer becomes peelable by heating. (14) The pressure-sensitive adhesive tape according to any one of (1) to (13), wherein the heating element is an electric conductor that generates heat when electricity is passed through it, and the pressure-sensitive adhesive tape is peeled off by the heat generated by the electric conductor.

[0008] (15) An article comprising at least two adherends and an adhesive tape according to any one of (1) to (14) between the two adherends, the two adherends being adhered to each other via the adhesive tape. (16) The article according to (15), wherein, in a plan view, the heating element constituting the pressure-sensitive adhesive tape has a pair of extending portions extending from an outer periphery of the adherend. (17) A method for dismantling an article according to (15) or (16), comprising the steps of: heating the heating element to melt and / or soften the melt-softening layer, thereby separating the two adherends. (18) The method for dismantling articles described in (17), wherein the heating of the heating element is resistance heating, the heating element is electrically connected to a power source, electricity is passed from the power source to the heating element, and the melt-softened layer is melted and / or softened by resistance heating to separate the two adherends. Effect of the Invention

[0009] According to the present invention, there is provided a pressure-sensitive adhesive tape which can be peeled off by heating in a short time, which can prevent thermal damage to an adherend, and which is easy to operate for peeling off by heating. Furthermore, according to the present invention, it is possible to provide an article in which at least two adherends are adhered via the adhesive tape, and a method for dismantling the article, which makes it possible to suppress thermal deterioration of adherends such as electronic components, enable reuse, and facilitate dismantling work. [Brief description of the drawings]

[0010] [Figure 1] 1 is a schematic cross-sectional view illustrating an example of a pressure-sensitive adhesive tape of the present invention. [Diagram 2] FIG. 2 is a schematic cross-sectional view showing another example of the pressure-sensitive adhesive tape of the present invention. [Diagram 3] FIG. 2 is a schematic plan view showing another example of the pressure-sensitive adhesive tape of the present invention. [Figure 4] 1A to 1C are schematic plan views showing examples of patterns of heating elements in the pressure-sensitive adhesive tape of the present invention. [Diagram 5] FIG. 2 is a schematic cross-sectional view showing another example of the pressure-sensitive adhesive tape of the present invention. [Figure 6]1 is a schematic plan view showing an example of an article of the present invention. [Figure 7] 1 is a schematic cross-sectional view showing an example of an article of the present invention. [Figure 8] 1A to 1C are diagrams illustrating a method for dismantling an article according to the present invention. [Figure 9] 1 is a schematic plan view of the pressure-sensitive adhesive tape of Example 1. FIG. [Figure 10] 1 is a schematic cross-sectional view of the pressure-sensitive adhesive tape of Example 1. [Figure 11] FIG. 2 is a schematic plan view showing an article of an example and an evaluation method. [Figure 12] FIG. 2 is a schematic front view showing an article of an example and an evaluation method. [Figure 13] FIG. 2 is a schematic side view showing an example article and an evaluation method. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Hereinafter, an embodiment of the present invention will be described in detail. In this specification, a numerical range indicated using "to" indicates a range including the numerical values ​​before and after "to" as the minimum and maximum values, respectively.

[0012] 1. Adhesive tape The present invention provides an adhesive tape comprising, at least in this order, an adhesive layer, a heating element, and a melt-softening layer adjacent to the heating element, the melt-softening layer containing a thermoplastic resin and an inorganic hollow filler. The adhesive tape of the present invention has a property that the melt-softened layer can be peeled off by heating, and can be used as an easily dismantled adhesive tape that can easily separate or dismantle the fixed adherends after a certain period of time has passed after application to the adherends and fixing the adherends together. Since the adhesive tape of the present invention has the above-mentioned configuration, it is not limited to the material of the adherends, maintains high adhesive strength when fixed between the adherends, and can be easily separated or dismantled by heating when separating or dismantling the adherends. Hereinafter, "separation or dismantling" will also be simply referred to as "dismantling".

[0013] The pressure-sensitive adhesive tape of the present invention has a heating element. The heating element is heated by directly passing an electric current through it or by heating means such as induction heating, infrared radiation, microwaves, or other external energy irradiation, thereby melting or softening the melt-softening layer adjacent to the heating element. In the present invention, since deterioration of the adherend caused by external energy irradiation can be suppressed and the article can be dismantled with the pressure-sensitive adhesive tape embedded in it, the heating element is preferably an electric conductor that generates heat when electric current is passed through it, and the pressure-sensitive adhesive tape of the present invention is preferably peeled off by the heat generated by the electric conductor. Here, the adhesive tape of the present invention has a melt-softening layer containing an inorganic hollow filler, which not only acts as a heat insulator to suppress the conduction of heat generated from a heating element to an adherend, but also acts to store heat in the melt-softening layer, thereby allowing the thermoplastic resin constituting the melt-softening layer to be efficiently melted or softened. Therefore, in the pressure-sensitive adhesive tape of the present invention, the adhesive strength decreases with heating due to the heat storage effect of the melt-softening layer, the residual adhesive strength after energization is small relative to the initial adhesive strength, and the rate of decrease in adhesive strength due to energization is large. Therefore, articles made using the pressure-sensitive adhesive tape of the present invention have excellent dismantling properties. In other words, because the adhesive tape of the present invention generates heat inside the tape, when an article having at least two adherends bonded via the adhesive tape of the present invention is dismantled, the article can be easily dismantled while reducing thermal damage to the adherends.

[0014] In addition, even in the case of an article to which electronic components that are built into a device and completely shielded from the outside and cannot access the adhesive tape are attached, the electronic components can be easily disassembled without preparing a large-scale device. In particular, when the adhesive tape is thermally disassembled using the driving current in the electronic components while the electronic components are built into the electronic device, thermal deterioration of the circuits in the electronic components can be prevented, and the electronic components can be thermally peeled off without the need for an external device, making the disassembly work easier.

[0015] The embodiment of the pressure-sensitive adhesive tape of the present invention "becomes peelable by heating" may be an embodiment in which the pressure-sensitive adhesive tape, particularly the melt-softened layer itself, melts or softens by heating, causing cohesive failure inside the melt-softened layer, and a part or all of the pressure-sensitive adhesive tape peels off from the adherend, or an embodiment in which the pressure-sensitive adhesive tape, particularly the melt-softened layer itself, melts or softens by heating, causing a decrease in its adhesive strength, causing peeling (interface failure) between the melt-softened layer and a layer adjacent to the melt-softened layer or the adherend, making a part or all of the pressure-sensitive adhesive tape peelable from the adherend. In addition, when the pressure-sensitive adhesive tape is peeled off by heating, the melt-softened layer may peel off from the adherend as a whole, or a part of the melt-softened layer may peel off from the adherend. In addition, the adhesive layer constituting the pressure-sensitive adhesive tape of the present invention is composed of a component that is less likely to melt or soften by heating than the component constituting the melt-softening layer, as described below. Furthermore, the melt-softening layer contains an inorganic hollow filler, so that the layer can store heat received from the heating element and retain heat. Therefore, the pressure-sensitive adhesive tape of the present invention can selectively melt or soften the melt-softening layer by heating the heating element, thereby making it peelable. The configuration of the pressure-sensitive adhesive tape of the present invention will be described below.

[0016] [Heater] The heating element can be appropriately selected from known heating elements depending on the heating means used. Examples of heating and heating means include resistance heating, electromagnetic induction heating, infrared heating, microwave heating, and thermal conduction. Among them, resistance heating is preferred from the viewpoint that the melt-softened layer can be sufficiently softened or melted even with a small amount of energy, and that the adhesive tape can be thermally dismantled using a driving current in an electronic component while being built into an electronic device, and that there is no need to heat the heating element using an external heat source via the adherend, and that excessive heating of the adherend can be prevented.

[0017] Here, "resistance heating" is a type of electrical heating method in which a current is passed through a resistive current-carrying body (heating body) and the current-carrying body is heated by the Joule heat generated. When a steady current is passed through a current-carrying body, the amount of Joule heat generated within a certain period of time is proportional to the square of the magnitude of the current and the resistance of the conductor (Joule's law). Current-carrying bodies have a resistance value (volume resistivity, etc.) that is specific to their material. "Electromagnetic induction heating" is a type of non-contact heating method for electrical heating, also known as high-frequency induction heating. When a resistive electric body (heating body) is placed in the magnetic field generated by passing a high-frequency current (alternating current) through a coiled conductor, a current flows through the electric body due to the principle of electromagnetic induction, and the electric body is heated by the Joule heat. "Infrared heating" and "microwave heating" are non-contact heating methods that utilize thermal energy radiated by electromagnetic waves in specific wavelength ranges, such as infrared rays and microwaves. The atomic bonds and molecules that make up a substance have thermal vibrations (molecular motion and crystal lattice vibrations) that correspond to the temperature of the substance itself, and when electromagnetic waves with a wavelength corresponding to this vibration frequency are absorbed, the molecular vibrations become more intense and heat is generated. "Heat conduction" is a heating method that utilizes the heat transfer phenomenon in which heat is transferred from a high temperature side to a low temperature side inside a solid. Heat can be transferred by directly contacting the heat source with a material that has excellent thermal conductivity.

[0018] When the heating means is resistance heating, the heating element is preferably a conductive material having resistance, for example, a metal, a nonmetal, or an organic / inorganic composite material. Examples of metals include nichrome (108 μΩ·cm), stainless steel such as SUS410 (62.2 μΩ·cm), SUS304 (72.0 μΩ·cm), and SUS430 (60.0 μΩ·cm), titanium (55.0 μΩ·cm), nickel silver (for example, 34.0 μΩ·cm for "Nickel Silver C7701" manufactured by Takeuchi Metal Foil and Powder Co., Ltd.), and metal fiber sheets (for example, "Stainless Fiber Sheet" manufactured by Tomoegawa Paper Co., Ltd.). The numbers in parentheses indicate the approximate volume resistivity of each material at 20°C. Among these, nichrome and stainless steel are preferred from the viewpoints that they are difficult to tear when made into a foil, are easy to handle as a tape, and can melt the melt-softened layer in a short period of time to greatly reduce the adhesive strength. Examples of nonmetals include carbon (3352 μΩ·cm, for example) such as carbon nanomaterials such as graphite, graphene, graphene oxide, carbon nanotubes, graphene platelets, and carbon nanofibers. Among these, carbon nanomaterials such as carbon nanotubes are preferred, because they are easily processed into a film, are unlikely to impair the physical properties required for a tape, such as conformability, are easily conductive even in small amounts, and can cause the melt-softened layer to melt in a short period of time due to resistance heating. Examples of organic-inorganic composite materials include metal-deposited films in which a metal such as aluminum or chromium is deposited on a polyester film, conductively plated woven or nonwoven fabrics, and conductively coated films.

[0019] When the heating means is resistance heating, the volume resistivity of the heating element at 20°C is preferably 30 μΩ·cm or more, more preferably 50 μΩ·cm or more, even more preferably 70 μΩ·cm or more, and particularly preferably 100 μΩ·cm or more. From the viewpoint of not increasing the voltage required when energizing the heating element too much, the volume resistivity of the heating element at 20°C is preferably 100,000 μΩ·cm or less, more preferably 20,000 μΩ·cm or less, even more preferably 10,000 μΩ·cm or less, and particularly preferably 5,000 μΩ·cm or less. Specifically, the volume resistivity of the heating element can be in the range of 30 to 100,000 μΩ·cm, 50 to 20,000 μΩ·cm, 70 to 10,000 μΩ·cm, or 100 to 5,000 μΩ·cm.

[0020] If the volume resistivity of the heating element is 30 μΩ·cm or more, when the heating element is connected to the wiring circuit in the electronic device and the driving current of the electronic device is passed through the heating element during dismantling of the article, only the adhesive tape can be heated, and high-temperature deterioration of the wiring circuit can be prevented. In addition, when a heating element with a volume resistivity in the above range is used, the melt-softening layer can be melted or softened in a short time, and the dismantling time can be shortened. Furthermore, when using a drive current in an electronic component, it is possible to prevent the electronic circuit and connections from being excessively heated due to current flow through a heating element, thereby preventing thermal deterioration of the electronic component.

[0021] The volume resistivity of the heating element can be measured at 20°C using a low resistivity meter (manufactured by Nitto Seiko Analytech Co., Ltd., product name "Loresta-AX MCT-T370") and a four-point probe (manufactured by Nitto Seiko Analytech Co., Ltd., product name "ASP Probe MCP-TP03P") in accordance with JIS K 7194. The measurement is performed at one point, and 4.532 is used as the correction coefficient for the resistivity.

[0022] When the heating means is electromagnetic induction heating, the heating element is preferably a current-carrying body having resistance, and examples of such materials include metals such as iron, aluminum, nickel, stainless steel, zinc, lead, and magnesium, as well as oxides and alloys of these metals. Among these, aluminum and iron are preferred.

[0023] When the heating means is infrared heating or microwave heating, the heating element is preferably a substance that has the property of absorbing a specific wavelength of infrared heating or microwave heating and generating thermal vibration (heat), and examples of such substances include organic substances and inorganic substances. Examples of organic substances include resins, rubbers, fibers, organic dyes, organic dyes, and organic pigments. Examples of inorganic substances include metallic inorganic substances, non-metallic inorganic substances, inorganic dyes, inorganic dyes, and inorganic pigments. Examples of metallic inorganic substances include non-ferrous metals such as aluminum, titanium, chromium, manganese, cobalt, nickel, magnesium, zinc, and copper; iron; and oxides of the aforementioned non-ferrous metals and iron. Examples of non-metallic inorganic substances include silicon, carbon, and silicon oxides (e.g., SiO2).

[0024] When the heating means is thermal conduction, the heating element is preferably a material with excellent thermal conductivity, such as metals and nonmetals. Examples of metals include aluminum, iron, copper, and oxides and nitrides of these metals. Examples of nonmetals include ceramics such as silicon carbide, graphite, etc.

[0025] When the heating means is resistance heating, the shape of the heating element is not particularly limited as long as the heating elements are in electrical contact with each other so as to generate resistance heating, and can be appropriately selected according to the purpose, for example, a planar shape, a mesh shape, a particulate shape, a fibrous shape, etc. Among them, a planar shape is preferred from the viewpoint that it can sufficiently adhere to the melt-softened layer in contact with the heating element before current is applied, and heat is generated on the surface when current is applied, so that the heating element itself is less likely to be destroyed or broken when electricity is applied. Examples of planar heating elements include metal foils made of the aforementioned metals; sheets of the aforementioned non-metals; resin films or sheets in which particles or fibers made of the aforementioned metals or non-metals are densely dispersed, such as metal-vapor-deposited films, woven or non-woven fabrics with conductive plating, or conductive-coated films; coatings of the aforementioned metals or non-metals; sheets in which non-woven fabrics are impregnated with the aforementioned metals or non-metals; and non-woven fabrics of the aforementioned metals or non-metals, such as metal fiber sheets. Among these, metal foil, nonmetallic sheet, metallic or nonmetallic coating film, metallic or nonmetallic nonwoven fabric are preferred, and metal foil is more preferred, since they can be heated over the entire surface and are less likely to break.

[0026] The planar heating element may be formed in a pattern, or may be in a strip or line shape (see also FIG. 4 described later). A strip or line heating element is advantageous in that it has high heat generation efficiency and is easy to peel off due to a small contact area with the adherend. In this case, the length of the heating element in the minor axis direction (strip width or line width) is preferably 0.5 to 20 mm, more preferably 1 to 10 mm, and even more preferably 2 to 5 mm.

[0027] When the planar heating element is patterned (has a pattern shape), the distance between the terminals (terminals for connecting to a power source) of the heating element can be increased, and the resistance can be increased. Therefore, the heating efficiency of the planar heating element is increased, and the adhesive tape of the present invention can be peeled off in a short time. When the planar heating element is patterned, the pattern width is not particularly limited and can be the same as the preferred range of the band width.

[0028] The planar heating element may be an embodiment in which the heating element is disposed on one or both sides of the substrate. In this case, the heating element is disposed so as to be in direct contact with one or both sides of the substrate. The heating element may be disposed so as to cover the entire area of ​​one or both sides of the substrate, and may be disposed in a line, strip or pattern. The substrate is not particularly limited as long as it can support the heating element, and from the viewpoints of the followability of the adhesive tape, thinning, heat resistance, etc., a film of a resin such as a polyester such as polyethylene terephthalate or polyethylene naphthalate, a polyolefin such as polypropylene, or a polyimide is preferable.

[0029] Examples of the mesh-shaped heating element include a planar heating element having a plurality of through holes, a mesh-shaped or lattice-shaped heating element, etc. These may be integrally molded heating elements.

[0030] In addition, the shape of the heating elements does not necessarily have to be integrally molded as long as the heating elements can be in electrical contact with each other. For example, the heating elements may be particles or fibers made of the metal or nonmetal, and particulate, mesh, or fibrous heating elements may be dispersed in the resin film as the base material, thereby forming electrical contact between the heating elements. When a particulate, mesh or fibrous heating element is dispersed in the resin film as the substrate, the content of the particulate or fibrous heating element in the resin film as the substrate is preferably 20 to 95 mass %, more preferably 40 to 90 mass %.

[0031] The average thickness of the planar heating element is usually 1 μm or more, preferably 2 μm or more, more preferably 3 μm or more, even more preferably 5 μm or more, and particularly preferably 10 μm or more. The average thickness of the planar heating element is preferably 200 μm or less, more preferably 150 μm or less, even more preferably 100 μm or less, and particularly preferably 50 μm or less. When the average thickness of the planar heating element is within the above-mentioned range, a sufficient amount of current and heat generation can be obtained, the heating element can be efficiently heated by resistance heating, and the adhesive tape has excellent conformability and application workability. The average thickness of the planar heating element is the average value of thicknesses measured at five or more arbitrarily selected locations. When the planar heating element is arranged on one or both sides of a substrate, the average thickness of the planar heating element refers to the thickness excluding the substrate, and when the heating elements are arranged on both sides of the substrate, the average thickness refers to the thickness of the heating element on each side.

[0032] When the heating means is electromagnetic induction heating or thermal conduction, the shape of the heating element can be appropriately selected, and may be, for example, a planar shape, a mesh shape, or a resin film or sheet in which particles or fibers of the heating element are densely dispersed. The planar heating element may be molded into a pattern, or may be strip-shaped or linear. When the heating element is strip-shaped or linear, the heating efficiency is high and the contact area with the adherend is small, so that peeling is easy. The length of the heating element in the minor axis direction (strip width or line width) is preferably 1 to 10 mm, more preferably 2 to 5 mm. The average thickness of the planar heating element is preferably 5 to 200 μm, more preferably 10 to 150 μm, and even more preferably 12 to 100 μm.

[0033] When the heating means is infrared heating or microwave heating, the heating element may be a resin film or sheet in which particles or fibers made of the heating element are densely dispersed. When the heating means is infrared heating, a pigment or the like may be used as the infrared absorbing material, and such a pigment may be dispersed in the resin film or sheet, or may be coated on the resin film or sheet by painting or the like.

[0034] The heating element may be manufactured as required, or a commercially available product may be used. Examples of commercially available products include planar heating elements such as nichrome foil, stainless steel foil, titanium foil, and nickel silver, such as "NCH1-H", "SUS304-H", "SUS430-H", "TR270C-H", and "Nickel Silver C7701" (all manufactured by Takeuchi Metal Foil and Powder Co., Ltd.); and "Stainless Steel Fiber Sheet" by Tomoegawa Paper Co., Ltd. Pattern-molded products of these may also be used.

[0035] [Adhesive layer] In the pressure-sensitive adhesive tape of the present invention, the components constituting the pressure-sensitive adhesive layer include, for example, acrylic adhesives, urethane adhesives, rubber adhesives such as synthetic rubber or natural rubber, silicone adhesives, and vinyl ether adhesives. Among them, pressure-sensitive adhesives that can be used as pressure-sensitive adhesives are preferred, and acrylic adhesives containing acrylic polymers are more preferred. Acrylic adhesives containing acrylic polymers are difficult to melt or soften by heating. Therefore, the heat generated from the heating element of the pressure-sensitive adhesive tape of the present invention can selectively melt or soften the melt-softening layer of the pressure-sensitive adhesive tape of the present invention, which will be described later. The pressure-sensitive adhesive is an adhesive that adheres by applying pressure for a short time at room temperature around 20°C, and has tackiness at room temperature.

[0036] Examples of acrylic polymers include homopolymers of (meth)acrylic acid ester monomers, and copolymers of (meth)acrylic acid ester monomers and other monomers. In this specification, "(meth)acrylic" is a general term for acrylic, methacrylic, and both. "(meth)acrylate" is a general term for acrylate, methacrylate, and both.

[0037] Examples of the (meth)acrylic acid ester monomer include (meth)acrylic acid alkyl esters having an alkyl chain having 1 to 14 carbon atoms, such as methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, butyl (meth)acrylate, hexyl (meth)acrylate, cyclohexyl (meth)acrylate, octyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, isononyl (meth)acrylate, isodecyl (meth)acrylate, and lauryl (meth)acrylate. The acrylic polymer may contain one kind of these monomers as a constituent unit, or may contain two or more kinds of them as a constituent unit.

[0038] The content of the (meth)acrylic acid ester monomer is preferably in the range of 70 to 99.9 mass % based on all the monomer components constituting the acrylic polymer, more preferably in the range of 80 to 99 mass %, and even more preferably in the range of 90 to 97 mass %.

[0039] In addition, a polar group-containing monomer may be included as another monomer for obtaining an acrylic polymer. Examples of the polar group-containing monomer include carboxylic acids having an ethylenically unsaturated group, such as (meth)acrylic acid, itaconic acid, itaconic anhydride, maleic acid, maleic anhydride, and crotonic acid; (meth)acrylates having a hydroxyl group, such as 2-hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, caprolactone-modified (meth)acrylate, polyoxyethylene (meth)acrylate, and polyoxypropylene (meth)acrylate; Examples of nitrogen-containing monomers having an ethylenically unsaturated group include (meth)acrylonitrile, N-vinyl-2-pyrrolidone, N-vinylcaprolactam, N-vinyllaurolactam, (meth)acryloylmorpholine, (meth)acrylamide, N,N-dimethyl(meth)acrylamide, N-methylol(meth)acrylamide, N-butoxymethyl(meth)acrylamide, N,N-dimethylaminomethyl(meth)acrylate, and 2-(perhydrophthalimide-N-yl)ethyl acrylate.

[0040] When used in combination with a crosslinking agent described below, a crosslinked structure can be formed between a hydroxyl group or a carboxyl group and the crosslinking agent, and the storage modulus of the adhesive layer can be adjusted. From this viewpoint, the polar group-containing monomer is preferably a (meth)acrylate having a hydroxyl group or a carboxylic acid having an ethylenically unsaturated group, and more preferably 2-hydroxyethyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, 6-hydroxyhexyl (meth)acrylate, or acrylic acid.

[0041] The content of the polar group-containing monomer in the acrylic polymer is preferably in the range of 0.1 to 20 mass %, more preferably in the range of 1 to 13 mass %, and still more preferably in the range of 1.5 to 8 mass %, based on the total monomer components constituting the acrylic polymer.

[0042] The weight average molecular weight of the acrylic polymer is preferably in the range of 400,000 to 1,400,000, more preferably in the range of 600,000 to 1,200,000, and even more preferably in the range of 650,000 to 1,100,000. Here, the weight average molecular weight is a weight average molecular weight measured by gel permeation chromatography (GPC) in terms of standard polystyrene. Specifically, the weight average molecular weight is determined under the following measurement conditions using a GPC measuring device "SC8020" manufactured by Tosoh Corporation. Sample concentration: 0.5% by mass (tetrahydrofuran solution) Sample injection volume: 100μL Eluent: Tetrahydrofuran (THF) ·Flow rate: 1.0mL / min Column temperature (measurement temperature): 40℃ Column: Tosoh Corporation's "TSKgel GMHHR-H" Detector: Differential Refraction

[0043] The adhesive layer may further contain a tackifier resin for the purpose of adjusting its adhesiveness. Examples of the tackifier resin include various tackifier resins such as rosin, polymerized rosin, polymerized rosin ester, rosin phenol, stabilized rosin ester, disproportionated rosin ester, hydrogenated rosin ester, terpene, terpene phenol, petroleum resin, C5 / C9 petroleum resin, and (meth)acrylate. Also usable are tackifier resins that are liquid at room temperature, such as process oil, polyester tackifier resin, and low molecular weight liquid rubber such as polybutene. When the adhesive layer contains a tackifier resin, the amount is preferably in the range of 1 to 150 parts by mass, more preferably 10 to 150 parts by mass, per 100 parts by mass of the base resin such as an acrylic polymer constituting the adhesive layer, from the viewpoint of improving the adhesiveness around room temperature (0 to 40°C) and exhibiting heat durability. Furthermore, when the adhesive layer contains a tackifier resin, the total content of the base resin and the tackifier resin in the adhesive forming the adhesive layer is preferably 50% by mass or more, more preferably 70% by mass or more, and even more preferably 90% by mass or more, based on the total solid content of the adhesive.

[0044] The adhesive layer may further contain a crosslinking agent for improving cohesive strength, such as known crosslinking agents including isocyanate, epoxy, aziridine, polyvalent metal salt, metal chelate, ketohydrazide, oxazoline, carbodiimide, silane, and glycidyl (alkoxy) epoxy silane.

[0045] The adhesive layer may further contain other additives, such as antioxidants, antiaging agents, colorants such as pigments and dyes, thickeners, leveling agents, film-forming assistants, infrared absorbers, ultraviolet absorbers, water repellents, etc., as necessary, within the scope that does not impair the effects of the present invention.

[0046] The adhesive layer may further include a thermoplastic resin, and from the viewpoint of selectively melting or softening the melt-softening layer by heat generated from the heating element in the adhesive tape of the present invention, the adhesive layer is preferably configured to be composed of a component that is difficult to melt or soften by heating, different from the thermoplastic resin contained in the melt-softening layer. More specifically, the adhesive layer is preferably configured to include a thermoplastic resin whose loss tangent (tan δ) is 0.8 or more at a temperature range of, for example, 40°C or more, higher than the temperature at which the tan δ of the thermoplastic resin-containing component other than the inorganic hollow filler constituting the melt-softening layer described below is 0.8 or more. In this specification, the "component that contains a thermoplastic resin and that constitutes the melt-softening layer, other than the inorganic hollow filler" will hereinafter be simply referred to as the "melt-softening resin composition." Details of the melt-softening resin composition will be described later.

[0047] The thickness of the adhesive layer is preferably in the range of 10 to 200 μm, more preferably in the range of 20 to 100 μm, from the viewpoint of adhesive strength with respect to the adherend and film uniformity during solution coating. The thickness of the adhesive layer is the average value obtained by measuring the thickness at any five points.

[0048] The melting point of the adhesive layer is preferably higher than the melting point of the melt-softening layer described later. Here, the "melting point of the adhesive layer" means the melting point of a composition (hereinafter simply referred to as "adhesive layer composition") composed of a tackifier resin, a crosslinking agent, other additives, and a thermoplastic resin different from the thermoplastic resin contained in the melt-softening layer, which are contained as necessary in an acrylic adhesive, a urethane adhesive, a rubber adhesive, a silicone adhesive, a vinyl ether adhesive, etc. that constitute the adhesive layer. The melting point of the adhesive layer (adhesive layer composition) is preferably, for example, 130°C or higher, and more preferably in the range of 130°C to 200°C. By adjusting the melting point of the adhesive layer to the above range and adjusting the melting point of the melt-softening layer to the range described later, the melting or softening of the melt-softening layer can be caused to occur prior to the melting or softening of the adhesive layer by the heat generated from the heating element. That is, when an article having a structure bonded by the adhesive tape of the present invention is thermally dismantled, the melting or softening of the melt-softening layer can be stably and preferentially caused to occur, and the article can be easily dismantled. The "melting point of the adhesive layer" is the temperature of the endothermic peak accompanying the melting of the adhesive layer (adhesive layer composition), measured by differential scanning calorimetry (DSC).

[0049] In a temperature range of 40° C. or higher, the temperature at which the adhesive layer (adhesive layer composition) has a tan δ of 0.8 or higher is preferably higher than the temperature at which the component (i.e., the melt-softening resin composition described below) containing a thermoplastic resin other than the inorganic hollow filler constituting the melt-softening layer has a tan δ of 0.8 or higher. In particular, the temperature at which the adhesive layer (adhesive layer composition) has a tan δ of 0.8 or higher is more preferably higher than the temperature at which the melt-softening resin composition has a tan δ of 1 or higher. Specifically, in the temperature range of 40°C or higher, the temperature when the tan δ of the adhesive layer (adhesive layer composition) is 0.8 is preferably higher than the temperature when the tan δ of the melt-softened resin composition is 0.8, more preferably higher than the temperature when tan δ is 1, and even more preferably higher than the temperature when tan δ is 1.2.

[0050] In one preferred embodiment of the adhesive layer (adhesive layer composition), the maximum value of tan δ in the temperature range of 80° C. to 160° C. is preferably less than 1, more preferably less than 0.8, and even more preferably 0.6 or less. From the viewpoint of allowing the adhesive layer to exhibit viscosity and elasticity, the tan δ of the adhesive layer (adhesive layer composition) in the temperature range of 80° C. to 160° C. is preferably 0.2 or more.

[0051] As one of the preferred embodiments of the adhesive layer, the temperature range in which the tan δ of the adhesive layer (adhesive layer composition) is 0.8 or more is preferably higher than 150° C., more preferably 170° C. or more. The upper limit of the above temperature range is not particularly limited, but can be, for example, 300° C., preferably 250° C. In the pressure-sensitive adhesive tape of the present invention, when the pressure-sensitive adhesive layer has such physical properties, when the pressure-sensitive adhesive layer and the melt-softening layer receive the same amount of heat from a heating element, melting and / or softening of the pressure-sensitive adhesive layer can be suppressed. That is, when an article having a structure bonded by the pressure-sensitive adhesive tape of the present invention is thermally dismantled, melting or softening of the melt-softening layer can be stably and preferentially caused while suppressing melting or softening of the pressure-sensitive adhesive layer, thereby enabling easy dismantling in a short time. From the viewpoint of being able to exhibit good adhesion to an adherend before and after dismantling, the adhesive layer (adhesive layer composition) has a tan δ at 23° C. of preferably 0.1 to 0.8, more preferably 0.2 to 0.6.

[0052] Tan δ of the adhesive layer (adhesive layer composition) is determined by dynamic viscoelasticity measurement at a frequency of 1 Hz. For example, a test piece of the adhesive layer composition with a dry thickness of about 2 mm is prepared, and the storage modulus G' and loss modulus (G") are measured using a viscoelasticity tester (ARES-G2, manufactured by TA Instruments Japan) under the conditions of a frequency of 1 Hz, a temperature range of -40°C to 200°C, and a heating rate of 2°C / min. Tan δ is calculated by the formula [tan δ=G" / G'].

[0053] The tan δ of the adhesive layer (adhesive layer composition) can be adjusted by the base polymer of the adhesive which is the main component, for example, the monomer species constituting the acrylic polymer described above, the combination and mixing ratio of each monomer, the amount of tackifier resin added as needed, the amount of crosslinking agent added as needed (gel fraction), etc.

[0054] [Melted and softened layer] The melt-softening layer constituting the pressure-sensitive adhesive tape of the present invention contains a thermoplastic resin and an inorganic hollow filler. <Inorganic hollow filler> Examples of inorganic hollow fillers include metal oxide ceramics such as alumina, silica, silica alumina, zirconia, and magnesia; non-oxide ceramics such as silicon carbide, boron carbide, nitrogen carbide, aluminum nitride, silicon nitride, and boron nitride; and hollow fillers made of inorganic substances such as glass, calcium carbonate, volcanic ash (shirasu), and fly ash. These may be used alone or in combination of two or more. In addition, the inorganic hollow filler may be subjected to a surface treatment such as hydrophobization with a silane coupling agent or a fluorine-based compound.

[0055] Among the above, from the viewpoint of providing an insulating effect that suppresses the conduction of heat generated from the heating element to the adherend while maintaining properties such as shear force and holding power in the melt-softening layer that constitutes the adhesive tape of the present invention, and from the viewpoint of being able to better exhibit the heat storage effect of the melt-softening layer, preferred is an inorganic hollow filler that is at least one type selected from the group consisting of glass hollow filler and silica hollow filler, and more preferred is a glass hollow filler. Inorganic hollow fillers made of glass are commercially available, such as the "Glass Bubbles" series (product name, manufactured by 3M Company); the "Q-CEL (registered trademark)" series, the "Sphericel (registered trademark)" series (all manufactured by Potters-Barotini Company); and "Glass Balloon" (product name, manufactured by Tomoe Engineering Co., Ltd.).

[0056] The particle size (average particle size) of the inorganic hollow filler is preferably equal to or smaller than the thickness of the melt-softened layer, from the viewpoint of making it easier to maintain the strength of the melt-softened layer in an adhesive state and easier to improve the heat storage function of the melt-softened layer, and is preferably in the range of 1 to 500 μm, more preferably in the range of 1 to 200 μm, more preferably in the range of 5 to 200 μm, more preferably in the range of 10 to 100 μm, and even more preferably in the range of 10 to 80 μm. The particle size of the inorganic hollow filler is the median diameter (D50) measured by a laser diffraction / scattering type particle size distribution measuring device.

[0057] The specific gravity (true density) of the inorganic hollow filler is usually 0.01 to 1.8 g / cm so that the inorganic hollow filler is easily dispersed in the melt-softened layer and the mass of the pressure-sensitive adhesive tape of the present invention is not excessively increased. 3 The range is preferably 0.02 to 1.5 g / cm 3 The range is more preferable.

[0058] The amount of inorganic hollow filler blended is usually preferably in the range of 5 to 80 volume % relative to the total volume of the melt-softening layer, and more preferably in the range of 10 to 65 volume %. Also, the amount of inorganic hollow filler blended is usually preferably in the range of 0.1 to 80 mass % relative to the total mass of the melt-softening layer, and more preferably in the range of 1.0 to 70 mass %. When the amount of inorganic hollow filler blended in the melt-softening layer is within the above range, it is advantageous from the viewpoint of enhancing the heat insulating effect of the melt-softening layer and being able to further exert its heat storage effect.

[0059] The inorganic hollow filler is preferably a filler that is unlikely to expand or foam when heated and does not substantially increase in volume when heated, and preferably has an expansion rate (volume ratio) of 1.5 times or less, and more preferably 1.2 times or less, when heated at 120°C to 160°C for 5 minutes.

[0060] <Thermoplastic resin> Examples of the thermoplastic resin include urethane-based resins, polycarbonates, vinyl chloride-based resins, acrylic-based resins, crystalline or non-crystalline polyester-based resins such as polyethylene terephthalate, polyamide-based resins, styrene-based resins, olefin-based resins, cellulose-based resins, silicone-based resins, fluorine-based resins, styrene-based thermoplastic elastomers, olefin-based thermoplastic elastomers, vinyl chloride-based thermoplastic elastomers, acrylic-based thermoplastic elastomers, urethane-based thermoplastic elastomers, ester-based thermoplastic elastomers, amide-based thermoplastic elastomers, etc. These may be used alone or in combination of two or more. From the viewpoint that the thermoplastic resin can be melted or softened by heat generated from the heating element of the pressure-sensitive adhesive tape of the present invention, and can melt or soften the melt-softened layer without containing any component that generates a peeling starting point at the adhesive interface or any component that causes a decrease in adhesive strength, such as a heat-foaming agent, thereby making the pressure-sensitive adhesive tape peelable, and also from the viewpoint that the thermoplastic resin preferably has a softening point and is advantageous in that the melt-softened layer rapidly becomes flexible at a temperature higher than the softening point and exhibits high deformability and fluidity, among the above-mentioned thermoplastic resins, urethane-based resins, acrylic-based resins, polyester-based resins, styrene-based thermoplastic elastomers, olefin-based thermoplastic elastomers, vinyl chloride-based thermoplastic elastomers, acrylic-based thermoplastic elastomers, urethane-based thermoplastic elastomers, ester-based thermoplastic elastomers, and amide-based thermoplastic elastomers are preferred, with styrene-based thermoplastic elastomers being more preferred.

[0061] The styrene-based thermoplastic elastomer is preferably a block copolymer consisting of a polymer block containing a structural unit derived from an aromatic vinyl compound and a polymer block containing a structural unit derived from a conjugated diene compound, or a hydrogenated product thereof. Specifically, polystyrene-polybutadiene diblock copolymer or its hydrogenated product, polystyrene-poly(ethylene-butylene) diblock copolymer (SEB), polystyrene-polybutadiene-polystyrene triblock copolymer (SBS) or its hydrogenated product, polystyrene-poly(ethylene-butylene)-polystyrene triblock copolymer (SEBS), polystyrene-polyisoprene diblock copolymer or its hydrogenated product, polystyrene-poly(ethylene-propylene) diblock copolymer (SEP), polystyrene-polyisoprene-polystyrene triblock copolymer (SBS ... Examples of suitable block copolymers include polystyrene-poly(ethylene-propylene)-polystyrene triblock copolymers (SEPS), polystyrene-polybutadiene-polystyrene-polybutadiene tetrablock copolymers (SBSB) and hydrogenated products thereof, polystyrene-polybutadiene-polystyrene-polybutadiene-polystyrene pentablock copolymers (SBSBS), styrene-based multiblock copolymers, and hydrogenated products of styrene-based random copolymers such as styrene-butadiene rubber (SBR) in which the ethylenic double bonds have been hydrogenated. Moreover, as the styrene-based thermoplastic elastomer, a commercially available product may be used.

[0062] The weight average molecular weight of the styrene-based thermoplastic elastomer is preferably in the range of 10,000 to 800,000, more preferably in the range of 30,000 to 500,000, and even more preferably in the range of 50,000 to 300,000. When the weight average molecular weight is in the above range, the storage modulus and loss tangent of the melt-softening layer can be easily adjusted to be within a desired range, and the melt-softening layer can be easily melted or softened by heating. The weight average molecular weight of the styrene-based thermoplastic elastomer can be determined in the same manner as the method for measuring the weight average molecular weight of the acrylic polymer described above.

[0063] The styrene-based thermoplastic elastomer may be used alone or in combination of two or more kinds. That is, the styrene-based thermoplastic elastomer may be one or more kinds of triblock copolymers, one or more kinds of diblock copolymers, or a mixture of triblock copolymers and diblock copolymers. Among these, from the viewpoints of the melt-softened layer exhibiting appropriate cohesive strength, having good adhesive strength around room temperature (0 to 40°C) before heating, and being easily melted or softened by heating, it is preferable that the styrene-based thermoplastic elastomer contains at least a diblock copolymer. The content of the diblock copolymer in the styrene-based thermoplastic elastomer is preferably in the range of 10 to 100% by mass, more preferably in the range of 10 to 90% by mass, and even more preferably in the range of 15 to 80% by mass, and particularly preferably in the range of 20 to 75% by mass, from the viewpoint of an excellent balance between adhesiveness at 20°C and meltability by heating.

[0064] The melt-softening layer melts or softens due to the heat generated by the heating element, and the adhesive strength during heating decreases compared to the adhesive strength at around room temperature (0 to 40° C.). The content of the thermoplastic resin in the melt-softening layer is preferably in the range of 30 to 95% by mass, more preferably in the range of 35 to 90% by mass, based on the total amount of the melt-softening layer. If the blending amount of the thermoplastic resin in the melt-softening layer is in the above-mentioned range, it is advantageous from the viewpoint of the coatability of the melt-softening layer and the control of the melt-softening temperature.

[0065] <Optional ingredients> The melt-softened layer may contain an organic hollow filler that does not expand or foam when heated, in addition to the inorganic hollow filler described above. The organic hollow filler has a hollow structure in which the shell is made of resin and the core is hollow. Examples of organic hollow fillers that do not expand or foam when heated include already expanded organic hollow fillers and already foamed organic hollow fillers. As with the inorganic hollow fillers described above, such organic hollow fillers can provide a heat storage effect for the melt-softened layer and a heat insulating effect for suppressing the conduction of heat generated from the heating element to the adherend. The organic hollow filler that does not expand or foam when heated refers to an organic hollow filler whose volume does not substantially increase when heated, and the expansion coefficient (volume ratio) when heated at 120°C to 160°C for 5 minutes is preferably 1.5 times or less, more preferably 1.2 times or less. Examples of the resin constituting the organic hollow filler include resins containing structural units derived from acrylonitrile, vinyl chloride, vinylidene chloride, styrene, vinyl acetate, ethylene, (meth)acrylic acid ester, etc. Examples include acrylonitrile-based polymers, vinylidene chloride-based polymers, acrylic polymers, styrene-based polymers, polyethylene-based polymers, etc.

[0066] The organic hollow filler that can be contained in the melt-softening layer is preferably a filler that does not expand or foam when heated, but may contain a small amount of organic hollow filler that expands or foams when heated (thermally expandable organic hollow filler or thermally foamable organic hollow filler) within a range that does not impede the effects of the present invention. The melt-softening layer may be substantially free of organic hollow filler that expands or foams when heated. Substantially free means, for example, that the amount of thermally expandable organic hollow filler or thermally foamable organic hollow filler is less than 10 parts by mass, preferably 5 parts by mass or less, more preferably 1 part by mass or less, even more preferably 0.5 parts by mass or less, and particularly preferably 0 parts by mass, relative to 100 parts by mass of the melt-softening resin composition.

[0067] The melt-softening layer may further contain a tackifier resin for the purpose of adjusting its adhesiveness. Details of the tackifier resin are the same as those described in the section on the adhesive layer. The melt-softening layer may further contain a crosslinking agent for the purpose of improving cohesive strength. Details of the crosslinking agent are the same as those described in the section on the adhesive layer. The melt-softening layer may further contain other additives, such as antioxidants, antiaging agents, colorants such as pigments and dyes, thickeners, leveling agents, film-forming assistants, infrared absorbers, ultraviolet absorbers, and water repellents, as necessary, within the scope of not impairing the effects of the present invention. When the melt-softening layer contains a tackifier resin, the amount is preferably in the range of 1 to 150 parts by mass, more preferably 10 to 150 parts by mass, relative to 100 parts by mass of the thermoplastic resin constituting the melt-softening layer, from the viewpoint of improving the adhesiveness around room temperature (0 to 40°C) and exhibiting heat durability. Furthermore, when the melt-softening layer contains a tackifier resin, the total content of the thermoplastic resin and tackifier resin constituting the melt-softening layer is preferably in the range of 20 to 99.9% by mass, more preferably 30 to 99.0% by mass, relative to the total total mass of all components constituting the melt-softening layer, i.e., the inorganic hollow filler, the thermoplastic resin, the tackifier resin, and optionally contained crosslinking agents and other additives.

[0068] <Physical properties of melt-softened layer> The melting point of the melt-softening layer is preferably lower than the melting point of the adhesive layer, specifically, preferably in the range of 80 to 200°C, more preferably in the range of 90 to 180°C, and even more preferably in the range of 100 to 160°C. Here, the "melting point of the melt-softening layer" means the melting point of a composition (i.e., a melt-softening resin composition) that is made up of components that include the thermoplastic resin other than the inorganic hollow filler that constitutes the melt-softening layer. In other words, the melt-softening resin composition is a composition that is made up of a thermoplastic resin that constitutes the melt-softening layer, excluding the inorganic hollow filler, and a tackifier resin, a crosslinking agent, other additives, and the like that are further contained as necessary. The "melting point of the melt-softening layer" means the melting point of such a melt-softening resin composition. When the melting point of the melt-softening layer is within the above range, the pressure-sensitive adhesive tape of the present invention can exhibit high adhesive strength before heating. Furthermore, when thermally dismantling an article having a structure bonded by the pressure-sensitive adhesive tape of the present invention, even if the amount of heat generated by the heating element is small, the melting or softening of the melt-softening layer can occur stably and preferentially, making it possible to easily dismantle the article in a short time. The "melting point of the melt-softened layer" is the temperature of the endothermic peak accompanying the melting of the melt-softened resin composition, as measured by differential scanning calorimetry (DSC).

[0069] The storage modulus G of the melt-softened resin composition at 23° C. 23 From the viewpoint of good adhesion between the adherends at room temperature (0 to 40°C), 3 Pa~1.0×10 9 Pa is preferred, 1.0×10 3 Pa~5.0×10 7 Pa is more preferable, 5.0×10 3 Pa~5.0×10 7 Pa is more preferable, and 5.0×10 3 Pa~5.0×10 6 More preferably, 5.0×10 Pa 3 Pa~1.0×10 6 Pa is particularly preferred. Storage modulus G of melt-softened resin composition at 120°C 120 From the viewpoint of easily separating the adherends by heating, 0 Pa~5.0×10 6 Pa is preferred, 1.0×10 3 Pa~1.0×10 6 Pa is more preferable, and 1.0×10 3 Pa~1.0×10 6 Pa is more preferable, and 5.0×10 3 Pa~5.0×10 5 The storage modulus G 120 When the temperature is within the above range, the melt-softening layer melts or softens in a short time upon heating, making it possible to peel off the layer.

[0070] The melt-softened resin composition preferably has a tan δ in a temperature range of 80° C. or higher (preferably a tan δ in a temperature range of 100° C. or higher) of 0.8 or higher, more preferably 1 or higher. As a preferred embodiment of the melt-softening layer, the temperature at which the melt-softening resin composition has a tan δ of 0.8 or more is lower than the temperature at which the adhesive layer (adhesive layer composition) has a tan δ of 0.8 or more. In detail, the temperature range at which the melt-softening resin composition has a tan δ of 0.8 or more is preferably 80°C or more, more preferably 80°C or more to 200°C or less, even more preferably 100°C or more to 160°C or less, and even more preferably 100°C or more to 130°C or less. More specifically, the temperature at which the tan δ of the melt-softened resin composition is 0.8 is preferably 80°C or higher, more preferably 80°C or higher and 200°C or lower, even more preferably 100°C or higher and 160°C or lower, and even more preferably 100°C or higher and 130°C or lower. Furthermore, the temperature at which the tan δ of the melt-softened resin composition is 1 is preferably 80° C. or higher, more preferably 80° C. or higher and 200° C. or lower, even more preferably 100° C. or higher and 180° C. or lower, and even more preferably 100° C. or higher and 130° C. or lower.

[0071] The difference between the temperature when the tan δ of the melt-softening resin composition is 0.8 (more preferably, the temperature when tan δ is 1) and the temperature when the tan δ of the adhesive layer (adhesive layer composition) is 0.8 (more preferably, the temperature when tan δ is 1) may be a temperature difference at which the melt-softening layer preferentially melts or softens when heated from the heating element, and is, for example, 10°C or more, preferably 25°C or more, even more preferably 30°C or more, and more preferably 50°C or more. In the pressure-sensitive adhesive tape of the present invention, when the melt-softening resin composition has such physical properties, when the pressure-sensitive adhesive layer and the melt-softening layer receive the same amount of heat from a heating element, the melt-softening layer is more likely to melt and / or soften preferentially. When the melt-softening layer reaches a desired dismantling temperature range described below due to the heat generated from the heating element, plastic deformation is more likely to occur due to melting or softening, and cohesive failure in the melt-softening layer can cause peeling within the melt-softening layer or at the interface between the melt-softening layer and an adjacent layer or adherend. That is, when an article having a structure bonded by the pressure-sensitive adhesive tape of the present invention is thermally dismantled, the melt-softening layer is stably and preferentially melted or softened, making it possible to easily dismantle the article in a short time. From the viewpoint of improving the adhesiveness before dismantling, the tan δ of the melt-softened resin composition at 23° C. is preferably 0.1 to 0.8, and more preferably 0.2 to 0.6.

[0072] The storage modulus G and tan δ of the components (melt-softened resin composition) containing thermoplastic resin other than the inorganic hollow filler that constitute the melt-softened layer are determined by dynamic viscoelasticity measurement. For example, a test piece of the melt-softened resin composition with a dry thickness of about 2 mm is prepared, and the storage modulus G' and loss modulus (G") are measured at each temperature using a viscoelasticity tester (ARES-G2, manufactured by TA Instruments Japan) under the conditions of a frequency of 1 Hz, a temperature range of -40°C to 200°C, and a heating rate of 2°C / min. Tan δ is calculated by the formula [tan δ=G" / G'].

[0073] Storage modulus G of melt-softened resin composition 23 , storage modulus G 120 The tan δ and melting point can be adjusted by the type and combination of thermoplastic resins, the amount of a tackifier resin added as required, the amount of a crosslinking agent added as required, and the like.

[0074] The thermal conductivity of the melt-softened layer is preferably in the range of 0.03 to 0.20 W / m K, more preferably in the range of 0.03 to 0.18 W / m K, and even more preferably in the range of 0.05 to 0.15 W / m K. When the thermal conductivity is within the above range, heat generated from the heating element is not transferred to the adherend but is easily stored in the melt-softened layer, and the melt-softened layer can be melted or softened in a short period of time, allowing for easy dismantling. The thermal conductivity of the melt-softened layer can be measured, for example, by a rapid thermal conductivity meter ("QTM-710" manufactured by Kyoto Electronics Manufacturing Co., Ltd.).

[0075] The thickness of the melt-softening layer can be 500 μm or less, preferably in the range of 10 to 200 μm, and more preferably in the range of 20 to 150 μm, from the viewpoints of coatability, adhesive strength to an adherend, and dismantling property. The thickness of the melt-softening layer is the average value obtained by measuring the thickness at any five points.

[0076] The pressure-sensitive adhesive tape of the present invention has at least one melt-softening layer adjacent to the heating element, but may have a melt-softening layer c1 adjacent to one side of the layered heating element and a melt-softening layer c2 adjacent to the other side of the heating element. The specific layer structure of the pressure-sensitive adhesive tape having two melt-softening layers will be described later.

[0077] [Layer structure of adhesive tape] 1 and 2, the first embodiment of the pressure-sensitive adhesive tape of the present invention may be a laminate embodiment in which the pressure-sensitive adhesive tape 10 has a planar heating element b, an adhesive layer a arranged on one side of the planar heating element b, and a melt-softening layer c arranged on the other side of the planar heating element b, and is laminated in the order of adhesive layer a / heating element b / melt-softening layer c. The heat generated by the heating element b melts or softens the melt-softening layer c adjacent to the heating element b, reducing the adhesive strength and making it possible to peel it off.

[0078] It is preferable that the planar heating element b has a pair of extension parts e that extend and are exposed from the outer periphery of the adhesive layer a and the melt-softened layer c in a plan view (see Figs. 3 and 4). The extension parts e may be provided at two or more independent locations, and the locations on the heating element are not particularly limited and can be appropriately selected depending on the purpose. The two extension parts e may be located on the same side of the outer periphery of the adhesive layer a and the melt-softened layer c (see Figs. 4(1) to (3)), or may be located on two different sides (see Figs. 3 and 4(4) to (6)).

[0079] The extensions e are preferably located on two opposing sides of the outer periphery of the adhesive layer a and the melt-softened layer c (see Figs. 4(4)-(6)), and are preferably located on approximately diagonal lines of the outer periphery of the adhesive layer a and the melt-softened layer c (see Figs. 4(2)-(7)). In addition, when the extensions e are located on the same side of the outer periphery of the adhesive layer a and the melt-softened layer c, it is preferable that the heating element b has a U-shape or a zigzag shape in plan view (see Figs. 4(1)-(4) and (8)), and may be located in close portions on the same side as long as the heating element b can uniformly heat the inner surfaces of the adhesive layer a and the melt-softened layer c (see Figs. 4(3) and (8)). This allows current to flow across the entire area of ​​the planar heating element b, further improving the heating efficiency.

[0080] The extensions e may be provided in three or more places (see FIG. 4(9)), and a desired pair (two places) may be selected appropriately to pass electricity through the heating element. The pair of extensions e of the heating element b functions as a pair of terminals for electrically connecting to a power source in the article dismantling method described later, and makes it possible to easily pass electricity through the heating element b.

[0081] The length of the extension is preferably 1 to 50 mm, more preferably 2 to 25 mm, from the viewpoint of facilitating contact with a power source or a heat generating source. Each extension may be bent in a direction different from the surface direction of the adhesive tape. For example, when the adherends are in a state of being stuck together, the extension may be folded in a direction perpendicular to the surface direction of the adhesive tape and stored, and when the adherends are to be released from the stuck together (at the time of dismantling), the extension may be folded again in the surface direction to bring the extension into contact with a power source or a heat generating source.

[0082] The pressure-sensitive adhesive tape of the present invention may also be, as a second embodiment, an embodiment in which the pressure-sensitive adhesive tape 20 is a laminate in which the pressure-sensitive adhesive layer a1 / heat generating element b / melt-softening layer c / adhesive layer a2 are laminated in this order, as shown in Fig. 5. Alternatively, the pressure-sensitive adhesive tape 20 may be a laminate in which the pressure-sensitive adhesive layer a1 / melt-softening layer c1 / heat generating element b / melt-softening layer c2 are laminated in this order, and in this case, the pressure-sensitive adhesive tape may further have an adhesive layer a2 on the side of the melt-softening layer c2 opposite to the heat generating element b side. That is, a second embodiment of the pressure-sensitive adhesive tape of the present invention includes a laminate having a heating element b, an adhesive layer a1 arranged on one side of the heating element b, a melt-softened layer c arranged on the other side of the heating element b, and an adhesive layer a2 on a side of the melt-softened layer c different from the side adjacent to the heating element b. Another example of the second embodiment includes a laminate having a heating element b, a melt-softened layer c1 and a melt-softened layer c2 arranged on both sides of the heating element b, an adhesive layer a1 arranged on a side of the melt-softened layer c1 different from the side adjacent to the heating element b, and an adhesive layer a2 arranged on a side of the melt-softened layer c2 different from the side adjacent to the heating element b. The heat generated by the heating element b melts or softens the melt-softening layer c1 or c2 adjacent to the heating element b, reducing the adhesive strength and making it possible to peel it off. The adhesive tape of the present invention according to the second embodiment, in which an adhesive layer is further provided on the surface (opposite surface) of the melt-softening layer different from the surface adjacent to the heating element, can increase the initial adhesive strength and increase the rate of decrease in adhesive strength due to heating. In plan view, the planar heating element b preferably has a pair of extension parts extending and exposed from the outer periphery of the adhesive layer a1, the adhesive layer a2, and the melt-softened layer c. Details of the extension parts are the same as those of the planar heating element b in the first embodiment.

[0083] The pressure-sensitive adhesive tape of the present invention may have a release layer (also called a release sheet or release liner). Examples of the release layer include lathing paper, kraft paper, clay-coated paper, paper laminated with a film such as polyethylene, paper coated with a resin such as polyvinyl alcohol or an acrylic acid ester copolymer, and synthetic resin films such as polyester or polypropylene coated with a fluororesin or silicone resin. The release layer may be present on one side or both sides of the pressure-sensitive adhesive tape of the present invention.

[0084] The adhesive tape of the present invention may have other layers, such as functional layers having functions such as insulating properties, heat insulation properties, or heat shielding properties, such as an insulating layer or a heat insulating layer (e.g., a foamed resin layer, a hollow-containing layer, a hollow particle-containing layer, etc.), in addition to the adhesive layer, heating element, and melt-softening layer, so long as the outermost layers (excluding the release layer) positioned opposite each other in the thickness direction have adhesive surfaces that can be bonded to an adherend.

[0085] In the pressure-sensitive adhesive tape of the present invention, the pressure-sensitive adhesive layer a and the melt-softening layer c in the above-mentioned first embodiment may be the adhesive surface with the adherend, and the pressure-sensitive adhesive layer a1 and the pressure-sensitive adhesive layer a2 in the above-mentioned second embodiment may be the adhesive surface with the adherend. In the second embodiment, the initial adhesive strength can be further increased.

[0086] The pressure-sensitive adhesive tape of the present invention may have the following exemplary configurations, but is not limited to these. In the following laminate configurations, " / " represents a laminate interface, and for example, in "Layer A / Layer B", Layer A and Layer B are adjacent to each other, i.e., in direct contact with each other. · Peeling layer / adhesive layer a / heating element b / melting and softening layer c Adhesive layer a / heating element b / melting and softening layer c / peeling layer ·Release layer / adhesive layer a / heating element b / melt-softening layer c / release layer Adhesive layer a / functional layer / heat generating element b / melting and softening layer c / peeling layer ·Release layer / adhesive layer a / functional layer / heating element b / melt-softening layer c / release layer · Peeling layer / adhesive layer a / heating element b / melting softening layer c / adhesive layer a Adhesive layer a / heating element b / melt-softening layer c / adhesive layer a / peeling layer · Peeling layer / adhesive layer a / heating element b / melting softening layer c / adhesive layer a / peeling layer · Peeling layer / adhesive layer a / heating element b / melting softening layer c / functional layer / adhesive layer a · Peeling layer / adhesive layer a / functional layer / heating element b / melting and softening layer c / adhesive layer a / peeling layer · Peeling layer / adhesive layer a / functional layer / heating element b / melting / softening layer c / functional layer / adhesive layer a / peeling layer · Peeling layer / adhesive layer a / melting softening layer c / heating element b / melting softening layer c / peeling layer

[0087] The thickness of the entire pressure-sensitive adhesive tape of the present invention is preferably in the range of 50 μm to 2000 μm, more preferably in the range of 50 μm to 1000 μm, and further preferably in the range of 50 μm to 800 μm. In this case, cushioning properties (flexibility) and the like can be imparted when bonding adherends together, and the handleability of the pressure-sensitive adhesive tape, such as mechanical strength and processability, can be further improved.

[0088] [Uses of adhesive tape] The pressure-sensitive adhesive tape of the present invention has both surfaces, excluding the release layer, that function as adhesive surfaces (adhesive surfaces), and therefore can be used suitably for bonding adherends to each other by laminating adherends to both surfaces of the pressure-sensitive adhesive tape. The pressure-sensitive adhesive tape of the present invention can be peeled off by heating, preferably by resistance heating, and therefore can be used suitably as a resistance heating (current heating) peeling tape in particular. The adhesive tape of the present invention can be suitably used, for example, for bonding between rigid adherends and for separating between adherends. The adhesive tape of the present invention can be easily peeled off by heating, and can be used in applications where peeling of the adhesive tape is required for separating between parts for the purpose of reuse or recycling. For example, it can be suitably used as an adhesive tape for fixing between parts of various products in industrial applications such as electronic devices, automobiles, building materials, OA, and home appliances, and can improve the work efficiency when separating between parts or peeling off labels.

[0089] [Adhesive tape manufacturing method] There is no particular limitation on the method for producing the adhesive tape of the present invention. For example, the adhesive tape of the first aspect of the present invention can be produced by applying a composition containing the components constituting the adhesive layer and a solvent on a release sheet and drying it to form an adhesive layer, applying a composition containing the components constituting the melt-softening layer and a solvent on another release sheet and drying it to form a melt-softening layer, and laminating them sequentially to each surface of a planar heating element. Here, the release sheet on the surface side of the melt-softening layer of the obtained adhesive tape is peeled off, and the adhesive layer formed in the form of a release sheet is further laminated to the exposed surface of the melt-softening layer, thereby producing the adhesive tape of the second aspect of the present invention. Alternatively, the adhesive layer formed in the form of a release sheet can be laminated to one side of a planar heating element, and then a composition containing the components constituting the melt-softening layer and a solvent can be applied to the other side of the planar heating element and dried to form a melt-softening layer, thereby producing the adhesive tape of the first aspect of the present invention described above.Also, the adhesive layer formed in the form of a release sheet can be further laminated to the surface of the melt-softening layer of the obtained adhesive tape, thereby producing the adhesive tape of the second aspect of the present invention described above. Furthermore, the composition containing the components constituting the adhesive layer and the composition containing the components constituting the melt-softening layer may be molded by extrusion molding, press molding, injection molding, or the like. The solvent is not particularly limited, and examples thereof include organic solvents such as toluene, xylene, ethyl acetate, butyl acetate, acetone, methyl ethyl ketone, hexane, etc.; water, or aqueous solvents mainly composed of water, etc. Although the solvent may remain in the adhesive layer and melt-softened layer of the obtained adhesive tape, it is usually preferable that no solvent is contained.

[0090] 2.Goods The present invention also provides an article comprising at least two adherends and the pressure-sensitive adhesive tape of the present invention between the two adherends, the two adherends being adhered to each other via the pressure-sensitive adhesive tape. The adherend may be rigid or flexible like a film, etc. The material and shape of the adherend are not particularly limited, and examples thereof include plate-shaped adherends made of resin, glass, or metal, housings, and covers, and parts having any of these on the adherend surface. The two adherends bonded via the adhesive tape may be the same or different. As a method for bonding the adherends, a method in which the adherends are attached to each of the adhesive surfaces of the adhesive tape of the present invention, respectively, and the two adherends are bonded together can be mentioned. The article is not particularly limited, but from the viewpoint of effectively utilizing the effects of the pressure-sensitive adhesive tape of the present invention, it is preferably, for example, an electronic device or a part built into an electronic device. In the article of the present invention, the heating element constituting the pressure-sensitive adhesive tape preferably has a pair of extending portions extending from the outer periphery of the adherend in plan view.

[0091] As shown, for example, in a schematic plan view in Fig. 6 and a schematic cross-sectional view in Fig. 7, the article 100 of the present invention is an article comprising two adherends 50 and an adhesive tape 10 including a laminate in which an adhesive layer a / planar heating element b / melt-softening layer c are laminated in this order between the two adherends 50, and the two adherends 50 are bonded together via the adhesive tape 10. In a plan view (Fig. 6), both ends in the major axis direction of the planar heating element b extend from the outer periphery of the adhesive layer a and the melt-softening layer c. Both ends of the extending adhesive tape 10 can be used as a pair of terminals for electrically connecting to a power source or ends for contacting a heat generating source in a method for dismantling an article described later when the heating means is either resistance heating or thermal conduction, and can easily heat the heating element b of the adhesive tape 10. In addition, as shown in Fig. 6, a smaller contact area between the adherend and the adhesive tape in plan view is advantageous in that the heating efficiency of the heating element is higher and dismantling is easier because dismantling is more likely to occur when heated. Furthermore, although not shown, the article of the present invention may be an article comprising two adherends and an adhesive tape as shown in FIG. 5 between the two adherends, the two adherends being adhered to each other via the adhesive tape.

[0092] In a plan view of the article, the adhesive tape may be attached to the entire area of ​​the adherend surface, which is the surface of the adherend on the adhesive tape side, or the adhesive tape may be attached to a part of the adherend surface. In particular, as shown in FIG. 6, it is preferable that the adhesive tape 10 is attached to a part of the adherend surface of the adherend 50. In this case, the plan view shape of the adhesive tape 10 in the article may be a belt-like or linear shape, or may be a pattern shape. If the contact area between the adherend and the adhesive tape is small, when the adhesive tape is peeled off from the adherend by resistance heating, a peeling starting point is easily generated between the adherend and the adhesive tape, which is advantageous in terms of easy peeling. Furthermore, when the article of the present invention is viewed in a plan view, and the adhesive tape is attached to the entire adhesion surface, which is the surface of the adherend facing the adhesive tape, the planar shape of the planar heating element in the adhesive tape may be the same shape as the planar shape of the adhesive tape, or may be band-shaped, linear or pattern-shaped.

[0093] 3. How to dismantle an item The present invention also relates to a method for dismantling the above-mentioned article of the present invention, which comprises melting or softening the melt-softening layer by heating with a heating element to separate the two adherends. The dismantling method of the present invention preferably includes a step (separation step) of melting or softening the melt-softening layer by heating with a heating element to separate at least two adherends, and may further include other steps as necessary. There are no particular limitations on the means and method for heating the heating element, and examples thereof include resistance heating, electromagnetic induction heating, infrared heating, microwave heating, heat conduction, etc. Of these, resistance heating is preferred.

[0094] When the heating of the heating element is resistance heating, the separation step is preferably a step of electrically connecting the heating element to a power source, passing electricity through the heating element from the power source, and melting or softening the melt-softened layer adjacent to the heating element by resistance heating to separate the two adherends. The power source may be an external power source or a driving power source for an article that is an electronic device or a part built into an electronic device. In addition, when the article is an electronic device or a part built into an electronic device and the power source is a driving power source for the electronic device, the separation step is preferably a step of electrically connecting the heating element to the driving power source and electric circuit of the electronic device, passing electricity from the driving power source to the heating element, and melting or softening the melt-softened layer by resistance heating to separate the two adherends. The method of electrical connection may be to electrically connect the heating element or a pair of extensions of the heating element extending from the outer periphery of the adhesive layer and the melt-softened layer to the power source using a known means such as an alligator clip. The electric circuit and the electrically connecting means are preferably formed of a conductive material having a volume resistivity different from that of the heating element material in the adhesive tape, and more preferably formed of a conductive material having a volume resistivity lower than that of the heating element. In this case, when the heating element and the electric circuit are electrically connected to pass electricity from the driving power source to the heating element, it is advantageous in that the heating element can be peeled off in a short time by efficiently applying a voltage to the heating element while preventing excessive heating of the electric circuit and the electrically connecting means.

[0095] The method of passing electricity can be appropriately selected depending on the size of the pressure-sensitive adhesive tape of the present invention or the type of heating element, and examples of the method include a method of applying a voltage of 0.1 to 200 V until the melt-softening layer melts or softens (for example, in the range of 0.5 seconds to 30 minutes). As shown in FIG. 8, a simple power source can be used. The heating element of the pressure-sensitive adhesive tape of the present invention is electrically connected to a power source, and a voltage is applied to the heating element to pass electricity, whereby the heating element and its surroundings are heated by resistance heating. This heating melts or softens the melt-softening layer, releasing the adhesive state and allowing it to be peeled off, and the bonded adherends can be disassembled.

[0096] The voltage applied to the heating element by energization is usually preferably in the range of 0.1 to 200 V, more preferably 0.5 to 150 V, and even more preferably 1.0 V to 100 V. In the pressure-sensitive adhesive tape of the present invention, even if a low voltage is applied, the melt-softened layer melts or softens in a short time, so that by applying a voltage in the above range in the separation step, the article can be disassembled in a short time without applying an excessive voltage, and damage to the article due to heat can be prevented. In particular, by applying a voltage that can be handled by articles such as small electronic devices and household electrical appliances, these articles can be easily disassembled.

[0097] The current applied to the heating element is not particularly limited, and is usually preferably in the range of 0.01 to 20 A, more preferably 0.03 to 15 A, even more preferably 0.05 to 10 A, and particularly preferably 0.1 to 5 A. Since the adhesive tape of the present invention melts or softens the melt-softening layer in a short time, if the current applied in the separation step is in the above range, the article can be disassembled in a short time by passing a current that flows in general-purpose electronic devices and home appliances, and damage to the article due to heat can be prevented. In particular, by applying a current that can be handled by small electronic devices and home appliances, these articles can be easily disassembled. The application time is not particularly limited, and is usually preferably 0.5 seconds to 30 minutes, more preferably 0.5 seconds to 120 seconds, and even more preferably 0.5 seconds to 30 seconds. When the application time is within the above range, the article is not damaged by heat and can be easily dismantled in a short time.

[0098] When the heating element is heated by electromagnetic induction heating, the separation step is preferably a step of melting or softening the melt-softened layer by electromagnetic induction heating using an electromagnetic induction heating means to separate the two adherends. There is no particular limitation on the electromagnetic induction heating means, and a known electromagnetic induction heating device can be appropriately selected.

[0099] When the heating element is either infrared heating or microwave heating, the separation step is preferably a step of melting or softening the melt-softened layer by either infrared heating using an infrared heating means or microwave heating using a microwave heating means to separate the two adherends. There are no particular limitations on the infrared heating means and microwave heating means, and publicly known infrared heating devices and microwave heating devices can be appropriately selected.

[0100] When the heating of the heating element is by thermal conduction, the separation step is preferably a step of contacting the heating element with a heat generating source, melting or softening the melt-softening layer by thermal conduction, and separating the two adherends. There is no particular limitation on the heat generating source, and a known heater can be appropriately selected. The method of heat conduction using the heat generating source can be appropriately selected depending on the size of the adhesive tape, the type of heating element, etc., and for example, a method of contacting the heating element and the heat generating source until the melt-softening layer melts or softens at a desired temperature can be mentioned.

[0101] The dismantling temperature of the article is preferably within the range of 80°C to 160°C, more preferably within the range of 90°C to 150°C, and even more preferably within the range of 100°C to 130°C. By setting the dismantling temperature within the above range, thermal damage to the article and adherend can be suppressed, and dismantling can be easily performed. In particular, when the pressure-sensitive adhesive tape is heated by resistance heating (current heating), by generating heat directly inside the tape, dismantling can be performed before the heat is transmitted to the article and adherend. The dismantling temperature of the article can be measured as the temperature of the heating element of the pressure-sensitive adhesive tape of the present invention (the temperature reached by the heating element during dismantling) using a temperature sensor using a thermocouple.

[0102] Although an embodiment of the adhesive tape, the article, and the method for dismantling an article of the present invention has been described above, the present invention is not limited to the configuration of the above-mentioned embodiment. For example, the adhesive tape of the present invention may have any other configuration in addition to the configuration of the above-mentioned embodiment, or may be replaced with any configuration that produces a similar effect. EXAMPLES

[0103] The present invention will be specifically described below with reference to examples. However, the present invention is not limited to the following examples. Materials used in the examples are shown below.

[0104] <Inorganic hollow filler> Hollow filler 1: "Glass Bubbles S38" (product name, manufactured by 3M, average particle size (median diameter) 40 μm, true density 0.38 g / cm 3 ) Hollow filler 2: "Glass Bubbles K15" (product name, manufactured by 3M, average particle size (median diameter) 60 μm, true density 0.15 g / cm 3 ) <Heater> Nichrome foil: "Nichrome NCH1-H" [Product name, manufactured by Takeuchi Metal Foil Powder Co., Ltd., thickness 10 μm. Volume resistivity 108 μΩ·cm (catalog value), 105 μΩ·cm (measured value)] <Release layer> Release liner: 75μm thick polyethylene terephthalate film with release treatment on one side

[0105] <Constituent materials of the melt-softening layer (melt-softening resin composition) excluding inorganic hollow filler> [Preparation Example 1] Styrene-isoprene block copolymer composition (mixture of styrene-isoprene diblock copolymer and styrene-isoprene triblock copolymer; styrene-derived structural unit 24% by mass, ratio of styrene-isoprene diblock copolymer to the total amount of the composition is 67% by mass) 100 parts by mass, Quinton G115 (C5 type / C9 type petroleum resin manufactured by Nippon Zeon Co., Ltd., softening point 115 ° C.) 40 parts by mass, Pencel D-160 (polymerized rosin ester resin manufactured by Arakawa Chemical Industries Co., Ltd., softening point 15 ° C. to 150 ° C.) 30 parts by mass, Nippon Oil Polybutene HV-50 (polybutene manufactured by JX Nippon Oil & Energy Corporation, pour point -12.5 ° C.) 5 parts by mass, and antioxidant (tetrakis [methylene-3- (3'5'-di-t-butyl-4-hydroxyphenyl) propionate] methane) 1 part by mass were mixed and dissolved in 100 parts by mass of toluene as a solvent to obtain a resin composition (P-1). The obtained resin composition (P-1) was applied to the release-treated surface of a release liner so that the thickness after drying would be approximately 2 mm to prepare a layer (P-1). Using a viscoelasticity tester (ARES-G2, manufactured by TA Instruments Japan), the storage modulus G' and loss modulus (G") were measured under conditions of a frequency of 1 Hz, a temperature range of -40°C to 200°C, and a heating rate of 2°C / min. The tan δ of the above resin composition (P-1) at a frequency of 1 Hz was calculated using the formula [tan δ=G" / G']. The melting point of the resin composition (P-1) is 140°C, and the storage modulus at 23°C G 23 is 2.5 x 10 5 Pa, and the storage modulus at 120 °C G 120 is 5.0 x 10 4 Pa, and the temperature when tan δ was 0.8 was 125° C. (the temperature range where tan δ was 0.8 or more was 125° C. or more).

[0106] <Materials constituting the adhesive layer> [Preparation Example 2] A reaction vessel equipped with a stirrer, reflux condenser, nitrogen inlet tube, and thermometer was charged with 79.9 parts by mass of n-butyl acrylate, 6 parts by mass of 2-ethylhexyl acrylate, 10 parts by mass of cyclohexyl acrylate, 4 parts by mass of acrylic acid, 0.1 parts by mass of 4-hydroxybutyl acrylate, and 200 parts by mass of ethyl acetate, and the mixture was obtained by bubbling nitrogen at 23°C for 1 hour under stirring. Next, 2 parts by mass of 2,2'-azobis(2-methylbutynitrile) solution (solid content 1.0% by mass) previously dissolved in ethyl acetate was added to the mixture, and the mixture was stirred at 72°C for 4 hours and then stirred at 75°C for 5 hours under stirring. Next, the mixture obtained was diluted with ethyl acetate and filtered through a 200-mesh wire net to obtain an acrylic copolymer (A-1) solution (solid content concentration 26%) having a weight average molecular weight of 1,060,000 and an average number of carbon atoms of the saturated hydrocarbon group of the alkyl acrylate monomer of 4.4. Composition (P-2) was obtained by blending 1.0 part by mass of an adduct of tolylene diisocyanate and trimethylolpropane as a crosslinking agent ("Burnoock D-40" manufactured by DIC Corporation, isocyanate-based crosslinking agent, solid content 40%, hereinafter referred to as "D-40") into 100 parts by mass of the obtained acrylic copolymer (A-1) solution. The obtained composition (P-2) was applied to the release-treated surface of a release liner so that the thickness after drying would be approximately 2 mm to prepare a layer (P-2). Using a viscoelasticity tester (ARES-G2, manufactured by TA Instruments Japan), the storage modulus G' and loss modulus (G") were measured under conditions of a frequency of 1 Hz, a temperature range of -40°C to 200°C, and a heating rate of 2°C / min. The tan δ of the above composition (P-2) at a frequency of 1 Hz was calculated by the formula [tan δ=G" / G']. The melting point of the composition (P-2) is 150°C or higher, and the storage modulus G at 23°C is 23 is 7.5 x 10 4 Pa, and the storage modulus at 120 °C G 120 is 5.5 x 10 4 Pa, and the temperature when tan δ was 0.8 was higher than 150°C (the temperature range where tan δ was 0.8 or higher was higher than 150°C). Moreover, the maximum value of tan δ in the temperature range from 100°C to 150°C was 0.4.

[0107] 1. Examples of adhesive tape and product manufacturing [Example 1] <Preparation of adhesive tape> The resin composition (P-1) was mixed with 30% by volume of hollow filler 1 to obtain adhesive (Y-1). The adhesive (Y-1) was applied to the release-treated surface of a release liner so that the thickness after drying would be 100 μm, and then dried at 90°C for 5 minutes to obtain a melt-softened layer c1 (thermal conductivity 0.18 W / m K). On the other hand, composition (P-2) was applied to the release-treated surface of another release liner so that the thickness after drying was 50 μm, and then dried at 90 °C for 3 minutes to prepare an adhesive layer (thermal conductivity 0.20 W / m K). The melt-softened layer c1 cut to an arbitrary width with a length of 50 mm and the nichrome foil with a length of 100 mm were laminated with a hand roller, and the nichrome foil was positioned so that both ends of the nichrome foil extended 25 mm in the length direction. Similarly, an adhesive layer cut to an arbitrary width with a length of 50 mm was laminated on the opposite side of the nichrome foil laminated with the melt-softened layer c1, and the adhesive layer was laminated with a roll with a linear pressure of 5 kg / cm from the upper surface of the release liner, and aged for 48 hours in an environment of 40 ° C. As a result, a laminate was produced in which both ends of the nichrome foil extended 25 mm from the outer periphery of the melt-softened layer c1 and the adhesive layer in the length direction of the nichrome foil, the total thickness excluding the release liner was 160 μm, and the layer structure excluding the release liner was laminated in the order of adhesive layer a1 / nichrome foil b / melt-softened layer c1. The obtained laminate was cut to a width of 2 mm, and an adhesive tape (T-1) was obtained in which the melt-softened layer c1 and the adhesive layer a1 were 2 mm wide x 50 mm long, the nichrome foil b was 2 mm long x 100 mm long, and the nichrome foil b had a pair of extensions extending from the outer periphery of the melt-softened layer c1 and the adhesive layer a1. A schematic plan view of the adhesive tape (T-1) is shown in Figure 9, and a schematic cross-sectional view is shown in Figure 10.

[0108] <Production of items> The release liner on the melt-softened layer c1 side of the adhesive tape of Example 1 (indicated by the symbol 10 in Figs. 11 to 13) was peeled off, and the tape was applied to an adherend 50a (glass, width 40 mm x length 50 mm x thickness 10 mm) so that the 50 mm length of the tape adhesive surface (effective portion) crossed the center of the adherend 50a along the width direction of the adherend 50a (see Figs. 11 to 13). Next, the release liner on the adhesive layer a1 side was peeled off, and the adhesive tape 10 was applied to an adherend 50b (glass, width 30 mm x length 100 mm x thickness 2.8 mm) in a shape that sandwiched the adhesive tape 10 (see Figs. 11 to 13), and the tape was applied under a pressure of 20 N / cm 2 The resulting patch was left to stand in an atmosphere of 23° C. and 50% RH for 24 hours or more to obtain the article of Example 1.

[0109] [Example 2] The resin composition (P-1) was mixed with 60 volume% of hollow filler 1 to obtain adhesive (Y-2). The adhesive (Y-2) was applied to the release-treated surface of a release liner so that the thickness after drying would be 100 μm, and then dried at 90°C for 5 minutes to obtain a melt-softened layer c2 (thermal conductivity 0.16 W / m K). Thereafter, the same procedures as in Example 1 were followed to produce an adhesive tape (T-2) and an article of Example 2.

[0110] [Example 3] The resin composition (P-1) was mixed with 30% by volume of hollow filler 2 to obtain adhesive (Y-3). The adhesive (Y-3) was applied to the release-treated surface of a release liner so that the thickness after drying would be 100 μm, and then dried at 90°C for 5 minutes to obtain a melt-softened layer c3 (thermal conductivity 0.16 W / m K). Thereafter, the same procedures as in Example 1 were followed to produce an adhesive tape (T-3) and an article of Example 3.

[0111] [Example 4] The resin composition (P-1) was mixed with 60 volume% of hollow filler 2 to obtain adhesive (Y-4). The adhesive (Y-4) was applied to the release-treated surface of a release liner so that the thickness after drying would be 100 μm, and then dried at 90°C for 5 minutes to obtain a melt-softened layer c4 (thermal conductivity 0.13 W / m K). Thereafter, the same procedures as in Example 1 were followed to produce an adhesive tape (T-4) and an article of Example 4.

[0112] [Comparative Example 1] The resin composition (P-1) was applied to the release-treated surface of a release liner so that the thickness after drying would be 100 μm, and then dried at 90 °C for 5 minutes to obtain a melt-softened layer c0 (thermal conductivity 0.20 W / m K). Thereafter, the same procedures as in Example 1 were followed to produce an adhesive tape (CT-1) and an article of Comparative Example 1.

[0113] [Example 5] <Preparation of adhesive tape> In the same manner as in Example 1, a melt-softening layer c1 and an adhesive layer were prepared. The melt-softened layer c1 cut to an arbitrary width with a length of 50 mm was laminated with a hand roller to a nichrome foil with a length of 100 mm, and the nichrome foil was positioned so that it extended 25 mm at each end in the length direction. Similarly, an adhesive layer cut to an arbitrary width with a length of 50 mm was laminated to the opposite side of the nichrome foil laminated with the melt-softened layer c1, and laminated from the upper surface of the release liner with a roll with a linear pressure of 5 kg / cm. Next, an adhesive layer cut to an arbitrary width with a length of 50 mm was attached to the surface of the melt-softened layer c1 from which the release liner was peeled off, and the top surface of the release liner was laminated with a roll with a linear pressure of 5 kg / cm, and aged for 48 hours in an environment of 40° C. As a result, a laminate was produced in which both ends of the nichrome foil extended 25 mm each from the outer periphery of the melt-softened layer and adhesive layer in the length direction of the nichrome foil, the total thickness excluding the release liner was 210 μm, and the layer configuration excluding the release liner was laminated in the order of adhesive layer a1 / nichrome foil b / melt-softened layer c1 / adhesive layer a2. The obtained laminate was cut to a width of 2 mm to obtain an adhesive tape (T-5) having a melt-softened layer and adhesive layer measuring 2 mm wide x 50 mm long, a nichrome foil measuring 2 mm x 100 mm long, and a pair of extension portions of the nichrome foil extending from the outer periphery of the melt-softened layer and adhesive layer.

[0114] <Production of items> For the adhesive tape of Example 5 (indicated by the symbol 10 in Figs. 11 to 13), the release liner on one adhesive layer a1 side was peeled off, and the tape was applied to an adherend 50a (glass, width 40 mm x length 50 mm x thickness 10 mm) so that the 50 mm length of the tape adhesive surface (effective portion) crossed the center of the adherend 50a along the width direction of the adherend 50a (see Figs. 11 to 13). Next, the release liner on the other adhesive layer a2 side was peeled off, and the adhesive tape 10 was applied to an adherend 50b (glass, width 30 mm x length 100 mm x thickness 2.8 mm) in a sandwiched shape (see Figs. 11 to 13), and the tape was applied with a pressure of 20 N / cm 2 The resulting patch was left to stand in an atmosphere of 23° C. and 50% RH for 24 hours or more to obtain an article of Example 5.

[0115] [Example 6] The resin composition (P-1) was mixed with 60% by volume of hollow filler 1 to obtain adhesive (Y-2). The adhesive (Y-2) was applied to the release-treated surface of a release liner so that the thickness after drying would be 100 μm, and then dried at 90°C for 5 minutes to obtain a melt-softened layer c2 (thermal conductivity 0.18 W / m K). An adhesive tape (T-6) and an article of Example 6 were produced in the same manner as in Example 5, except that the melt-softening layer c2 was used instead of the melt-softening layer c1 in Example 5.

[0116] [Example 7] The resin composition (P-1) was mixed with 30% by volume of hollow filler 2 to obtain adhesive (Y-3). The adhesive (Y-3) was applied to the release-treated surface of a release liner so that the thickness after drying would be 100 μm, and then dried at 90°C for 5 minutes to obtain a melt-softened layer c3 (thermal conductivity 0.16 W / m K). An adhesive tape (T-7) and an article of Example 7 were produced in the same manner as in Example 5, except that the melt-softening layer c3 was used instead of the melt-softening layer c1 in Example 5.

[0117] In the examples and comparative examples, the thermal conductivity of the melt-softening layer and the adhesive layer was measured using a rapid thermal conductivity meter ("QTM-710" manufactured by Kyoto Electronics Manufacturing Co., Ltd.).

[0118] 2. Evaluation For the articles obtained in each of the Examples and Comparative Examples, the push strength was measured as follows using the device shown in Figs. (1) Push strength before heating The articles obtained in each of the Examples and Comparative Examples were used as test pieces, and in an environment of 23°C, a glass plate was pressed at the pressing position in FIG. 11 with a probe 70 shown in FIGS. 12 and 13 in the direction of the arrow at a speed of 10 mm / min, to measure the strength at which the adhesive tape peeled off [push strength (G1)]. (2) Push strength after 10 seconds of heating The articles obtained in each of the Examples and Comparative Examples were used as test pieces, and the extension e of the nichrome foil (heating element) in the adhesive tape 10 of each test piece was clamped with an alligator clip 60, and a current of 0.5 A or 1.0 A was passed using a DC stabilized power supply (manufactured by Kikusui Electronics Co., Ltd., product name "PAS160-1"). 10 seconds after the start of current flow, the glass plate was pushed in the direction of the arrow with a probe 70 shown in Figures 12 and 13 at a speed of 10 mm / min while continuing to pass the current, and the strength at which the adhesive tape peeled off [push strength (G2)] was measured. The temperature of the heating element when heated and dismantled at 0.5 A was approximately 100°C, and the temperature of the heating element when heated and dismantled at 1.0 A was approximately 160°C. The temperature of the heating element when heated and dismantled was measured using a temperature sensor that used a thermocouple. (3) Residual adhesive strength and push strength reduction rate Using the push strength (G1) and the push strength (G2), the residual adhesive strength and the push strength reduction rate were calculated according to the following formula, and the dismantling property was evaluated according to the following criteria. Residual adhesive strength (%)=100×G2 / G1 Push strength reduction rate (%) = 100 x [1-(G2 / G1)] [Evaluation criteria for dismantling] ◎: Residual adhesion rate is less than 50% ○: Residual adhesion rate is 50% or more and less than 65% △: Residual adhesion rate is 65% or more The above results are summarized in Table 1.

[0119] [Table 1]

[0120] The pressure-sensitive adhesive tapes of the Examples have a smaller push strength after heating due to electrical current than the Comparative Examples. In particular, when the electrical current is 1 A, the residual adhesive strength after electrical current is smaller than the initial adhesive strength, and the reduction rate of the adhesive strength due to electrical current (reduction rate of push strength) is larger than that of the Comparative Examples. Moreover, the adhesive tapes of Examples 5 to 7, in which an adhesive layer is further provided on the side of the melt-softening layer opposite to the side adjacent to the heating element, have higher initial push strength than the adhesive tape of Comparative Example, and the rate of decrease in adhesive strength due to electrical current (rate of decrease in push strength) is greater than that of the adhesive tape of Comparative Example. In other words, the adhesive strength is weakened by heat from the heating element due to the heat storage effect of the melt-softening layer, and the articles made using the adhesive tape of each Example have excellent dismantling properties. [Industrial Applicability]

[0121] The pressure-sensitive adhesive tape of the present invention can be peeled off by heating in a short time, can prevent thermal damage to the adherend, and is easy to peel off by heating. Therefore, the pressure-sensitive adhesive tape of the present invention can be suitably used in applications where peeling of the pressure-sensitive adhesive tape is required when separating parts for the purpose of reuse or recycling, for example, as a pressure-sensitive adhesive tape for fixing parts of various products in industrial applications such as electronic devices, automobiles, building materials, OA, and home appliances, and improves the work efficiency when separating parts and peeling labels. [Explanation of symbols]

[0122] a, a1, a2: Adhesive layer b: Heating element c: Melted and softened layer e: Extension part (of heating element) 10, 20, 30: Adhesive tape 50, 50a, 50b: Adherent 100: Goods 60: Alligator clip 70: Probe P: Press position

Claims

1. An adhesive tape comprising: an adhesive layer; a heating element; and a melt-softening layer adjacent to the heating element, at least in this order; the melt-softening layer containing a thermoplastic resin and an inorganic hollow filler.

2. 2. The pressure-sensitive adhesive tape according to claim 1, wherein the thermoplastic resin constituting the melt-softening layer comprises a block copolymer or a hydrogenated product thereof, the block copolymer comprising a polymer block containing a structural unit derived from an aromatic vinyl compound and a polymer block containing a structural unit derived from a conjugated diene compound.

3. The pressure-sensitive adhesive tape according to claim 1, wherein a blending amount of the inorganic hollow filler in the melt-softening layer is in the range of 5 to 80 volume %.

4. The pressure-sensitive adhesive tape according to claim 1, wherein the inorganic hollow filler has an average particle size in the range of 1 to 200 μm.

5. The pressure-sensitive adhesive tape according to claim 1 , wherein the inorganic hollow filler is at least one selected from the group consisting of a glass hollow filler and a silica hollow filler.

6. The pressure-sensitive adhesive tape according to claim 1, wherein the melt-softening layer has a thickness in the range of 10 to 200 μm.

7. The pressure-sensitive adhesive tape according to claim 1, wherein the melt-softened layer has a thermal conductivity in the range of 0.03 to 0.20 W / m·K.

8. 2. The pressure-sensitive adhesive tape according to claim 1, wherein a temperature range in which a loss tangent (tan δ) of a component other than the inorganic hollow filler that contains the thermoplastic resin and that constitutes the melt-softening layer is 0.8 or more is 80° C. or higher.

9. 2. The pressure-sensitive adhesive tape according to claim 1, wherein the temperature at which the loss tangent (tan δ) of the pressure-sensitive adhesive layer becomes 0.8 or more is higher than the temperature at which the loss tangent (tan δ) of a component other than the inorganic hollow filler that contains the thermoplastic resin and that constitutes the melt-softening layer becomes 0.8 or more.

10. The pressure-sensitive adhesive tape according to claim 1 , wherein the heating element has a volume resistivity of 30 μΩ·cm or more at 20° C.

11. The pressure-sensitive adhesive tape according to claim 1 , wherein the heating element has a pair of extending portions extending from outer peripheries of the pressure-sensitive adhesive layer and the melt-softening layer in a plan view.

12. The adhesive tape according to claim 1 , further comprising an adhesive layer on the other side of the melt-softening layer opposite to the surface adjacent to the heating element.

13. The pressure-sensitive adhesive tape according to claim 1 , wherein the melt-softening layer becomes peelable by heating.

14. The pressure-sensitive adhesive tape according to claim 1 , wherein the heating element is an electric conductor that generates heat when an electric current is passed through the heating element, and the pressure-sensitive adhesive tape is peeled off by the heat generated by the electric conductor.

15. At least two adherends; The adhesive tape according to any one of claims 1 to 14 is provided between two adherends, An article in which the two adherends are bonded together via the adhesive tape.

16. The article according to claim 15 , wherein, in a plan view, the heating element constituting the pressure-sensitive adhesive tape has a pair of extension portions extending from an outer periphery of the adherend.

17. The method for dismantling an article according to claim 15, wherein the melt-softening layer is melted and / or softened by heating with the heating element to separate the two adherends.

18. 18. The method for dismantling articles according to claim 17, wherein the heating of the heating element is resistance heating, the heating element is electrically connected to a power source, and electricity is passed from the power source to the heating element, thereby melting and / or softening the melt-softened layer by resistance heating to separate the two adherends.

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