Adhesive tape, article, and method for disassembling the article

Abstract

The present invention provides an adhesive tape which is able to be removed by heating in a short time, while being capable of excellently preventing thermal damage to an adherend.　The present invention provides an adhesive tape which comprises: an intermediate layer A that contains a heating element and an adhesive; an adhesive layer B1 which is arranged on one surface side of the intermediate layer A, while containing an adhesive; and an adhesive layer B2 which is arranged on the other surface side of the intermediate layer A, while containing an adhesive. At least one of the adhesive layer B1 and the adhesive layer B2 forms a thermal insulation layer C which additionally has thermal insulation properties, or alternatively, a thermal insulation layer C which has thermal insulation properties is additionally arranged between the intermediate layer A and the adhesive layer B1 and / or between the intermediate layer A and the adhesive layer B2; and this adhesive tape becomes removable by means of heating.

Description

Technical Field

[0001] The present invention relates to an adhesive tape, an article, and a method for disassembling the article.

Background Art

[0002] Adhesive tapes are used as joining means with excellent workability and high adhesion reliability in various industrial fields such as OA equipment, IT products, home appliances, and automobiles for parts fixing applications, temporary fixing applications of parts, label applications for displaying product information, and the like. In recent years, from the perspective of global environmental protection, in various industrial fields such as these home appliances and automobiles, the requirements for recycling and reusing used products have been increasing. When recycling and reusing various products, it is necessary to peel off the adhesive tapes used for fixing parts and labels. However, since the adhesive tapes are provided at various locations in the products, reduction of the work cost by a simple removal process is desired.

[0003] In order to separate adherends from each other, for example, a hot melt adhesive composition that is quickly melted 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 disassembling a building has been proposed in which a metal base material is heated by an electromagnetic induction heating device, the adhesive between this base material and the interior material is heated and foamed to be peeled off, and the interior material is peeled off from the metal base material (see, for example, Patent Document 2). Further, a double-sided adhesive tape having a thermally conductive layer that can be easily disassembled has been proposed by bringing it into contact with a heat generation source and directly heating the thermally conductive layer (see, for example, Patent Document 3).

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, in the conventional method of peeling and disassembling by heating, since heat is applied from the outside, if an attempt is made to generate the amount of heat required for peeling the adhesive tape from the heating element, heat deterioration or heat damage may occur to the adherend due to the generated heat. On the other hand, if an attempt is made to suppress heat deterioration or heat damage to the adherend, there is a problem that the amount of heat generation decreases and the adhesive tape is not sufficiently heated, making peeling difficult to occur.

[0006] Therefore, there is a demand for an adhesive tape that can fix adherends such as rigid bodies to each other and has a function of disassembling and reusing the parts as adherends. In particular, there is a need for an adhesive tape that has a function of being easily disassembled and peeled by heating.

[0007] An object of the present invention is to solve the above-mentioned conventional problems and achieve the following objects. That is, an object of the present invention is to provide an adhesive tape, an article, and a method for disassembling an article that enable heat peeling in a short time and can excellently prevent heat damage to the adherend.

Means for Solving the Problems

[0008] The present invention is based on the above-mentioned findings by the present inventors, and the means for solving the above-mentioned problems are as follows. That is, <1> An intermediate layer A containing a heating element and an adhesive, an adhesive layer B1 disposed on one surface side of the intermediate layer A and containing an adhesive, and an adhesive layer B2 disposed on the other surface side of the intermediate layer A and containing an adhesive, wherein at least one of the adhesive layer B1 and the adhesive layer B2 is a heat insulating layer C having further heat insulating properties, or at least one of the space between the intermediate layer A and the adhesive layer B1 and the space between the intermediate layer A and the adhesive layer B2 further has a heat insulating layer C having heat insulating properties, and it is characterized in that it can be peeled by heating. <2> The pressure-sensitive adhesive tape according to <1>, having a heat insulation layer C between both the intermediate layer A and the adhesive layer B1 and between the intermediate layer A and the adhesive layer B2, respectively. <3> The pressure-sensitive adhesive tape according to any one of <1> to <2>, wherein the heat insulation layer C is selected from the group consisting of a foam layer, a hollow-containing layer, and a hollow particle-containing layer. <4> The pressure-sensitive adhesive tape according to any one of <1> to <3>, wherein the thickness of the heat insulation layer C is 15 μm to 1,000 μm. <5> The pressure-sensitive adhesive tape according to any one of <1> to <4>, wherein the volume resistivity of the heating element is 30 μΩ·cm or more. <6> The pressure-sensitive adhesive tape according to <5>, wherein the heating element is selected from the group consisting of nichrome, stainless steel, titanium, brass, and carbon. <7> The pressure-sensitive adhesive tape according to any one of <1> to <6>, wherein the intermediate layer A is a laminate having a planar heating element and adhesive layers a1 and a2 on each surface of the planar heating element. <8> The pressure-sensitive adhesive tape according to <7>, wherein in a plan view, the planar heating element has a pair of extending portions extending from the outer peripheries of the adhesive layer a1 and the adhesive layer a2. <9> The pressure-sensitive adhesive tape according to any one of <7> to <8>, wherein at least one of the adhesive layer a1 and the adhesive layer a2 softens or melts by heating. <10> The pressure-sensitive adhesive tape according to any one of <1> to <6>, wherein the intermediate layer A consists of a single layer containing the heating element and the adhesive. <11> The pressure-sensitive adhesive tape according to any one of <1> to <10>, wherein the intermediate layer A softens or melts by heating. <12> The pressure-sensitive adhesive tape according to any one of <1> to <11>, wherein the temperature at which the loss tangent (tanδ) of the adhesive layer formed by the adhesive becomes 0.45 or more exists in a temperature range of 80°C or more and 200°C or less. <13> An article comprising at least two adherends and the adhesive tape according to any one of <1> to <12> between the two adherends, wherein the two adherends are adhered via the adhesive tape. <14> The article according to <13>, wherein in a plan view, the adhesive tape has a pair of extending portions extending from the outer periphery of the adherend. <15> A method for disassembling the article according to any one of <13> to <14>, characterized by separating the two adherends by softening or melting the intermediate layer A by heating the heating element. <16> The method for disassembling an article according to <15>, wherein the heating of the heating element is resistance heating, the intermediate layer A and the power source are electrically connected, the heating element is energized from the power source, and the adhesive layer A is softened or melted by resistance heating to separate the two adherends.

Advantages of the Invention

[0009] According to the present invention, the above-mentioned various problems in the prior art can be solved, the above-mentioned object can be achieved, heating and peeling can be performed in a short time, and an adhesive tape, an article, and a method for disassembling the article that can excellently prevent thermal damage to the adherend can be provided.

Brief Description of the Drawings

[0010]

Figure 1A

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Figure 1C

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Figure 9C

MODE FOR CARRYING OUT THE INVENTION

[0011] In this specification, "adhesion" is a kind of adhesion, which means adhesion by pressure, and is also referred to as "pressure-sensitive adhesion". Correspondingly, an "adhesive" is an adhesive that has both liquid and solid properties, has tackiness, and exerts an adhesive action by pressure, and is also referred to as a "pressure-sensitive adhesive".

[0012] 1. Adhesive Tape The adhesive tape of the present invention has at least an intermediate layer A, an adhesive layer B1, an adhesive layer B2, and a heat insulation layer C, and may further have other layers such as a release layer as required. The adhesive tape of the present invention is an adhesive tape that can be peeled off by heating.

[0013] The pressure-sensitive adhesive tape of the present invention can be used as an easily disassemblable pressure-sensitive adhesive tape that can easily disassemble the fixation between adherends after a certain period of time after being attached to an adherend or fixing between adherends. That is, it becomes peelable by heating the intermediate layer A, and the adhered adherends can be disassembled. Compared with the conventional method of peeling and disassembling by heating, the pressure-sensitive adhesive tape of the present invention has a heat insulation layer, so that the heat generated in the intermediate layer A is difficult to escape (preventing heat diffusion), and sufficient heat can be obtained for the intermediate layer A to be heat-peeled (in particular, the adhesive in the intermediate layer A melts or softens). Further, the pressure-sensitive adhesive tape of the present invention has a heat insulation layer, so that the heat generated in the intermediate layer A is difficult to be transmitted to the adherend side, and heat deterioration of the adherend can be suppressed. In particular, when a direct current is directly passed through a heating element by resistance heating to heat an adhesive or an arbitrary melting / softening layer near the heating element, even a small amount of energy can release the adhesion state at the intermediate layer A itself or at a desired position within the intermediate layer A, making the intermediate layer A peelable and the adhered adherends disassemblable. Furthermore, when the pressure-sensitive adhesive tape is thermally disassembled using the drive current in an electronic component while being built into an electronic device, heat deterioration of the circuit in the component can be prevented, and it becomes heat-peelable without an external device or the like, facilitating the disassembly work.

[0014] When it is said that the pressure-sensitive adhesive tape of the present invention "becomes peelable by heating", it may be a mode in which the pressure-sensitive adhesive tape becomes integral and peelable from the adherend by heating, or it may be a mode in which peeling occurs within the pressure-sensitive adhesive tape, particularly within the intermediate layer A or between the intermediate layer A and the layer adjacent to the intermediate layer A, so that a part of the pressure-sensitive adhesive tape becomes peelable from the adherend. Also, when the pressure-sensitive adhesive tape peels by heating, the intermediate layer A may peel from the adherend integrally, or a part of the intermediate layer A may peel from the adherend.

[0015] <Intermediate layer A> The intermediate layer A contains at least a heating element and an adhesive, and further contains other components as required. The intermediate layer A may be a single layer or may be composed of a plurality of layers. Further, both surfaces of the intermediate layer A may be layers having adhesiveness or may be layers not having adhesiveness. When both surfaces of the intermediate layer A have adhesiveness, it means that both surfaces of the intermediate layer A may have pressure-sensitive adhesiveness, both surfaces of the intermediate layer A may have thermo-adhesiveness, or one surface of the intermediate layer A may have pressure-sensitive adhesiveness and the other surface may have thermo-adhesiveness. Among them, it is preferable that both surfaces of the intermediate layer A have pressure-sensitive adhesiveness because it can be easily adhered to an adherend or other layers constituting the adhesive tape of the present invention at room temperature and can be firmly adhered until heated.

[0016] <<Heating element>> The heating element is not particularly limited, and a known heating element can be appropriately selected according to the heating means to be used. The heating and heating means are not particularly limited, and known heating means can be appropriately selected according to the purpose. Examples thereof include electromagnetic induction heating, infrared heating, microwave heating, heat conduction, resistance heating, and the like. Among these, resistance heating is preferable from the viewpoint that an adhesive (or any molten softening layer) can be sufficiently softened or melted even with a small amount of energy, for example, the adhesive tape can be thermally decomposed using the drive current in the electronic component in a state built in an electronic device, and it is not necessary to heat the heating element using an external heat source through the adherend, and overheating of the adherend can be prevented.

[0017] Here, "electromagnetic induction heating" is a non-contact heating method, which is a type of electric heating method and is also called high-frequency induction heating. When a current-carrying body (heating element) with resistance is placed in a magnetic field generated by passing a high-frequency current (alternating current) through a coiled conductor, a current flows through the current-carrying body due to the principle of electromagnetic induction, and the current-carrying body is heated by the Joule heat. "Resistance heating" is a type of electric heating method, in which a power source is connected to a current-carrying body (heating element) with resistance to pass a current, and the current-carrying body is heated by the Joule heat. When a current flows through the current-carrying body, the amount of Joule heat generated within a certain time is proportional to the square of the magnitude of the current and the resistance of the conductor (Joule's law). The current-carrying body has a resistance value (such as low volume efficiency) inherent to the substance.

[0018] "Infrared heating" and "microwave heating" are non-contact heating methods that utilize thermal energy by radiation using electromagnetic waves in a specific wavelength range such as infrared rays and microwaves. The bonds and molecules that make up a substance undergo thermal vibrations (molecular motion and crystal lattice vibrations) corresponding to the temperature of the substance itself. When the substance absorbs electromagnetic waves with a wavelength corresponding to this vibration frequency, the molecular vibrations become intense and heat is generated. "Heat conduction" is a heating method that utilizes the heat transfer phenomenon in which heat is transferred from the high-temperature side to the low-temperature side inside a solid, and the heat generation source can be directly brought into contact with a substance with excellent heat conductivity to transfer heat.

[0019] When the heating means is resistance heating, the heating element is preferably a current-carrying body having resistance. For example, metals, non-metals, etc. are preferably mentioned. Examples of the metal include nichrome (108 μΩ·cm); stainless steels such as SUS 410 (62.2 μΩ·cm), SUS304 (72.0 μΩ·cm), SUS430 (60.0 μΩ·cm); titanium (55.0 μΩ·cm); brass (for example, in the case of "Brass C7701" manufactured by Takeuchi Metal Foil Co., Ltd., 34.0 μΩ·cm), etc. The numerical values in parentheses indicate approximately the volume resistivity values of each substance at 20°C. Examples of the non-metal include carbon such as carbon nanomaterials such as graphite (graphite), graphene, graphene oxide, carbon nanotubes, graphene platelets, carbon nanofibers (for example, 3,352 μΩ·cm), etc. Among these, from the viewpoint of being difficult to tear when made into a metal foil, being easy to handle as a tape, and being able to melt or soften the adhesive layer in a short time to significantly reduce the adhesive force, nichrome, stainless steel, etc. are preferable. Also, in addition to showing a high volume resistivity, it is easy to make it into a thin film shape and it is difficult to impair physical properties such as the followability required for the tape, so carbon is preferable. Among them, because of its rod shape, it is easy to exhibit conductivity even in a small amount and it is possible to cause melting or softening of the adhesive layer A by resistance heating in a short time, so carbon nanomaterials such as carbon nanotubes are preferable.

[0020] When the heating means is resistance heating, the volume resistivity of the heating element is preferably 30 μΩ·cm or more, more preferably 50 μΩ·cm or more, still more preferably 70 μΩ·cm or more, and particularly preferably 100 μΩ·cm or more at room temperature (20 °C). Further, the upper limit value of the volume resistivity of the heating element is not particularly limited. However, if the volume resistivity is too high, a high voltage is required during energization. Therefore, it is preferably 100,000 μΩ·cm or less, more preferably 20,000 μΩ·cm or less, still 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 μΩ·cm to 100,000 μΩ·cm, 50 μΩ·cm to 20,000 μΩ·cm, 70 μΩ·cm to 10,000 μΩ·cm, or 100 μΩ·cm to 5,000 μΩ·cm. When the volume resistivity of the heating element is 30 μΩ·cm or more, when using resistance heating to connect to the wiring circuit in the electronic device and energize the drive current of the electronic device to the heating element during the disassembly of the article, only the adhesive tape can be heated, and high-temperature deterioration of the wiring circuit can be prevented. In this case, it is preferable that the volume resistivity of the heating element is higher than the volume resistivity of the wiring circuit in the electronic device.

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

[0022] When the heating means is electromagnetic induction heating, the heating element is preferably a current-carrying body having resistance. For example, iron, aluminum, nickel, stainless steel, zinc, lead, magnesium, and their metal oxides and alloys are preferably mentioned. Among these, aluminum and iron are more preferable.

[0023] When the heating means is either infrared heating or microwave heating, the heating element is preferably a substance having the property of absorbing a specific wavelength of infrared heating or microwave heating and generating heat vibration (heat generation), and examples thereof include organic substances and inorganic substances. Examples of the organic substances include resins, rubbers, fibers, organic dyes, organic pigments, and the like. The organic substance is preferably a component of the adhesive in the intermediate layer A. The inorganic substance may be any substance that generates heat upon receiving infrared heating or microwaves, and examples thereof include metal-based inorganic substances, non-metal-based inorganic substances, inorganic dyes, inorganic pigments, and the like. Examples of the metal-based inorganic substances include non-ferrous metals such as aluminum, titanium, chromium, manganese, cobalt, nickel, magnesium, zinc, copper, etc.; iron; oxides of at least any one of the non-ferrous metals and iron, and the like. Examples of the non-metal-based inorganic substances include silicon, carbon; oxides such as silica (e.g., SiO2), and the like.

[0024] When the heating means is heat conduction, the heating element is preferably a substance having excellent thermal conductivity, and examples thereof include metals and non-metals. Examples of the metals include aluminum, iron, copper, oxides and nitrides of these metals, and the like. Examples of the non-metals include ceramics such as silicon carbide, graphite, and the like.

[0025] When the heating means is resistive 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 resistive 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. may be mentioned. Among them, a planar shape is preferable because it can be sufficiently adhered to other layers in contact with the heating element before energization, and when energized, it generates heat on the surface, making it less likely for the heating element itself to be destroyed or the wire to break during energized disassembly. Examples of the planar heating element include a metal foil made of the above metal, a non-metal sheet, a resin sheet in which particles or fibers made of the above metal or non-metal are densely dispersed, a coating film made of the above metal or non-metal, a sheet impregnated with the above metal or non-metal in a non-woven fabric, a non-woven fabric made of the above metal or non-metal, and the like. Among these planar heating elements, a metal foil, a non-metal sheet, a coating film made of a metal or a non-metal, or a non-woven fabric made of a metal or a non-metal is more preferable, and a metal foil is even more preferable because it can heat the entire surface with a high volume resistance and is less likely to break the wire.

[0026] The planar heating element may cover the entire surface of the adhesive layer in a plan view of the adhesive tape, or may cover a part of the adhesive layer. Further, the planar heating element may be formed in a pattern shape, or may be in a strip shape or a linear shape. When the heating element is in a strip shape or a linear shape, it is advantageous in terms of high heating efficiency and easy peeling because the contact area with the adherend is small. In that case, the length in the short-axis direction (strip width or line width) of the heating element is preferably 0.5 mm to 20 mm, more preferably 1 mm to 10 mm, and even more preferably 2 mm to 5 mm.

[0027] Also, when the planar heating element is in a pattern shape (has a pattern shape), the distance between the terminals (terminals for connecting to the power source) of the heating element can be increased, and the resistance can be increased. For this reason, 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. The line width of the pattern when the planar heating element is in a pattern shape is not particularly limited, but can be the same as the preferable range of the strip width or the line width.

[0028] In the case of a planar heating element, the heating element may be disposed on one or both sides of the base material. When the heating element is disposed on one or both sides of the base material, the heating element may be disposed so as to cover the entire one or both sides of the base material, or may be disposed in a linear, strip-like or pattern-like manner. In the case where the planar heating element is disposed on one or both sides of the base material, the heating element is disposed so as to be in direct contact with one or both sides of the base material. The base material is not particularly limited as long as it can support the heating element, but a resin film is preferably used from the viewpoints of the followability of the adhesive tape and thinning of the film. Examples of the resin film include general-purpose films such as polyethylene terephthalate (PET) films, polyester resin films such as polyethylene naphthalate (PEN), imide resin films such as polyimide (PI) films, and polyolefin resin films such as polypropylene (PP) films. Further, it may be a resin film used for the melt-softening layer described later.

[0029] Examples of the mesh-shaped heating element include an integrally formed heating element such as a planar heating element having a plurality of through holes, a mesh-shaped or lattice-shaped heating element, and the like.

[0030] Also, even if the heating elements are not integrally formed, it is sufficient that the heating elements can be electrically contacted with each other. For example, they may be particles or fibers made of the metal or the non-metal. By dispersing particulate or fibrous heating elements in an adhesive, even if the heating elements are not integrally formed, it is sufficient that electrical contact between the heating elements can be formed. When particles or fibers made of a heating element are dispersed in an adhesive, the content of the particles or fibers is not particularly limited as long as electrical contact between the heating elements is formed, and can be appropriately selected according to the purpose. However, it is preferably 20% by mass to 95% by mass, and more preferably 40% by mass to 90% by mass, based on the total amount of the adhesive. When the intermediate layer A is a single layer formed by an adhesive and the heating element is included in the single layer, the content of the particles or fibers can be the content based on the total amount of the intermediate layer A. Also, when the intermediate layer A is a laminate and has an adhesive layer a in which particles or fibers of a heating element are dispersed in one of the layers constituting the laminate, the content of the particles or fibers can be the content based on the total amount of one adhesive layer a.

[0031] The average thickness of the planar heating element is not particularly limited and can be appropriately selected according to the purpose. However, it is preferably 1 μm to 200 μm, preferably 2 μm to 200 μm, preferably 3 μm to 150 μm, more preferably 5 μm to 150 μm, preferably 5 μm to 100 μm, more preferably 10 μm to 100 μm, and preferably 10 μm to 50 μm. The average thickness of the planar heating element is an average value obtained by measuring the thicknesses at five or more arbitrarily selected locations. The larger the average thickness of the planar heating element, the greater the current flowing and the amount of heat generated. However, the thickness is limited from the viewpoints of the followability of the adhesive tape and the workability of sticking. On the other hand, when the average thickness of the planar heating element is within the above-described range, a sufficient amount of current and heat can be obtained, the heating element can be efficiently heated by resistance heating, and excellent followability of the adhesive tape and workability of sticking can be obtained.

[0032] When the planar heating element is arranged on one or both sides of the base material, the average thickness of the planar heating element refers to the thickness excluding the resin film. When the heating element is formed on both sides of the resin film, it refers to the thickness of the heating element for each side.

[0033] As the heating element, those appropriately manufactured or commercially available products may be used. There is no particular limitation on the commercially available products, and they can be appropriately selected according to the purpose. For example, nichrome foils such as nichrome NCH1-H; stainless steel foils such as stainless steel SUS304-H and stainless steel SUS430-H; titanium foils such as titanium type 1 TR270C-H; brass such as brass C7701 (all of the above are manufactured by Takeuchi Metal Foil & Powder Industry Co., Ltd.) and other planar heating elements. Also, those obtained by pattern-molding these can be used.

[0034] When the heating means is either electromagnetic induction heating or heat conduction, the shape of the heating element is not particularly limited and can be appropriately selected according to the purpose. For example, it may be planar, mesh-shaped, or a dispersion of particles or fibers made of the heating element in an adhesive. When the heating means is electromagnetic induction heating and heat conduction, as the planar heating element, it may cover the entire surface of the adhesive layer or a part of the adhesive layer. Also, it may be formed in a pattern shape, or may be strip-shaped or linear. When the heating element is strip-shaped or linear, it is advantageous in terms of high heating efficiency and easy peeling due to the small contact area with the adherend. In that case, the length (strip width or line width) in the short axis direction of the heating element is preferably 1 mm to 10 mm, more preferably 2 mm to 5 mm. The average thickness of the planar heating element is not particularly limited and can be appropriately selected according to the purpose, but is preferably 5 μm to 200 μm, more preferably 10 μm to 150 μm, and even more preferably 12 μm to 100 μm.

[0035] When the heating means is either infrared heating or microwave heating, the heating element is preferably dispersed in the adhesive or in the melt-softening layer described below, and more preferably is a component of the adhesive in the intermediate layer A. When the heating means is infrared heating, pigments or the like can be used as the infrared absorption material, and they may be dispersed in the adhesive or in the resin, or may be thinly film-coated in the intermediate layer A which is a laminate.

[0036] <<Adhesive>> The adhesive is not particularly limited and can be appropriately selected according to the purpose, but it is preferably at least one of a pressure-sensitive adhesive and a hot-melt adhesive. By using a hot-melt adhesive or a pressure-sensitive adhesive containing a thermoplastic resin as the adhesive contained in the intermediate layer A, the resin can be melted or softened by heat. Therefore, for example, components such as a heating foaming agent that generate a starting point of peeling at the adhesive interface or components that cause a decrease in adhesive strength do not need to be mixed, which is advantageous in terms of being peelable. Further, the adhesive preferably has a softening point, and in this regard, it is advantageous in that it becomes rapidly flexible and exhibits high deformability and fluidity when the temperature becomes higher than the softening point.

[0037] When the resin of the adhesive melts or softens by heating, the adhesive strength during heating is lower than the adhesive strength at room temperature.

[0038] The storage elastic modulus G measured by the dynamic viscoelastic spectrum of the adhesive (the adhesive layer formed by the adhesive) at 1 Hz and 23 °C 23 is preferably from 1.0×10 3 Pa to 1.0×10 9 Pa from the viewpoint of favorably fixing the adherends in the normal state, more preferably from 1.0×10 3 Pa to 5.0×10 7 Pa, still more preferably from 5.0×10 3 Pa to 5.0×10 7 Pa, even more preferably from 5.0×10 3 Pa to 5.0×10 6 Pa, and most preferably from 5.0×10 3Pa~1.0×10 6 Pa is particularly preferred.

[0039] Among them, when the adhesive is a pressure-sensitive adhesive (adhesive), the storage elastic modulus G measured by the dynamic viscoelastic spectrum of the pressure-sensitive adhesive (pressure-sensitive adhesive layer) at 1 Hz and 23 °C 23 From the viewpoint of firmly fixing the adherends to each other in the normal state (non-heated state), the storage elastic modulus G described above 23 Among the ranges, 1.0×10 3 Pa~5.0×10 7 Pa is preferred, 5.0×10 3 Pa~5.0×10 6 Pa is more preferred, 5.0×10 3 Pa~1.0×10 6 Pa is even more preferred.

[0040] Also, when the adhesive is a hot-melt adhesive, the storage elastic modulus G measured by the dynamic viscoelastic spectrum of the hot-melt adhesive (hot-melt adhesive layer) at 1 Hz and 23 °C 23 From the viewpoint of firmly fixing the adherends to each other in the normal state (non-heated state), 1.0×10 3 Pa~1.0×10 9 Pa is preferred, 5.0×10 3 Pa~5.0×10 8 Pa is more preferred, 1.0×10 4 Pa~1.0×10 8 Pa is even more preferred.

[0041] The storage elastic modulus G of the adhesive (adhesive layer formed by the adhesive) measured by the dynamic viscoelastic spectrum at 1 Hz and 100 °C 100 From the viewpoint of easily separating the adherends from each other by heating, 1.0×10 0 Pa~5.0×10 6 Pa is preferred, 1.0×10 3 Pa~1.0×10 6 Pa is preferred, 1.0×10 3 Pa~1.0×10 6 Pa is more preferred, 5.0×103 Pa to 5.0×10 5 Pa is more preferable.

[0042] Among them, when the adhesive is a pressure-sensitive adhesive (adhesive), the storage elastic modulus G measured by the dynamic viscoelastic spectrum of the pressure-sensitive adhesive (pressure-sensitive adhesive layer) at 1 Hz and 100 °C 100 is, as the storage elastic modulus G described above 100 Among the ranges of, 1.0×10 2 Pa to 5.0×10 6 Pa is preferable, and 1.0×10 3 Pa to 1.0×10 6 Pa is more preferable, and 5.0×10 3 Pa to 5.0×10 5 Pa is even more preferable. By setting the storage elastic modulus G of the pressure-sensitive adhesive (pressure-sensitive adhesive layer) within the above range, the pressure-sensitive adhesive can be melted or softened in a short time by heating and can be peeled off. 100

[0043] When the adhesive is a pressure-sensitive adhesive, the storage elastic modulus G 23 , and the storage elastic modulus G 100 can be measured by the following method. Using a viscoelasticity tester (ARES-G2, manufactured by TA Instruments Japan), a test piece is sandwiched between parallel disks with a diameter of 8 mm, which is the measurement part of the tester, and the storage elastic modulus G' is measured 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, and the values at 23 °C and 100 °C are used. As the test piece, a pressure-sensitive adhesive layer (adhesive layer) formed by applying a pressure-sensitive adhesive so that the dry thickness becomes about 2 mm using an applicator, drying, and curing as necessary was used.

[0044] Also, when the adhesive is a hot-melt adhesive, the storage elastic modulus G 23 , and the storage elastic modulus G 100 ​The test piece was sandwiched between the tensile measurement jigs which are the measurement parts of the viscoelasticity tester, and the storage elastic modulus G’ was measured 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, and the values at 23°C and 100°C were used. As the test piece, a hot melt adhesive layer formed by applying and drying a hot melt adhesive so that the thickness becomes about 0.1 mm after drying using an applicator was used.

[0045] It is preferable that the temperature at which the loss tangent (tanδ) of the adhesive (the adhesive layer formed by the adhesive) is 0.45 or more exists in the temperature range of 80°C or more and 200°C or less. More preferably, the temperature at which the tanδ is 0.8 or more exists in the temperature range of 80°C or more and 200°C or less. Even more preferably, the temperature at which the tanδ is 1.0 or more exists in the temperature range of 80°C or more and 200°C or less.

[0046] Since the temperature at which the tanδ of the adhesive (the adhesive layer formed by the adhesive) becomes a predetermined value or more exists in the temperature range of 80°C or more and 200°C or less, when the adhesive reaches that temperature due to heat reception from the heating element, plastic deformation is likely to occur due to melting or softening, and it is advantageous in that peeling and disintegration are likely to occur in a shorter time due to cohesive failure within the layer formed by the adhesive. When the intermediate layer A has the adhesive layer a1 and the adhesive layer a2 as described later, it is preferable that at least one of the adhesive layer a1 and a2 has a temperature at which the loss tangent (tanδ) is 0.45 or more in the temperature range of 80°C or more and 200°C or less.

[0047] Incidentally, the loss tangent (tanδ) is obtained from the storage elastic modulus (G’) and the loss elastic modulus (G”) obtained by dynamic viscoelasticity measurement due to temperature dispersion, according to the formula tanδ = G” / G’. The dynamic viscoelasticity measurement is the same as the measurement method of the storage elastic modulus G 23 and the storage elastic modulus G 100 described above.

[0048] The storage elastic modulus G of the adhesive (adhesive layer) 23 The storage elastic modulus G 100, and the loss tangent (tanδ) can be adjusted by adjusting the types and combinations of the monomers constituting the resin (base polymer) that is the main component of the adhesive, the blending ratio of each monomer, the blending amount of the tackifier resin added as necessary, the addition amount of the crosslinking agent added as necessary (gel fraction of the adhesive), etc. The resin (base polymer) that is the main component of the adhesive may be used alone or in combination of two or more. The resin that is the main component of the adhesive will be described in the section of "- Resin -" below. Further, when the adhesive layer contains a heating element, the storage modulus G 23 of the storage modulus G 100 , and the loss tangent (tanδ) shall be the values of the adhesive (adhesive layer) excluding the heating element.

[0049] The adhesive preferably has a melting point of 70°C or higher and 150°C or lower, more preferably 75°C or higher and 130°C or lower, and even more preferably 80°C or higher and 110°C or lower. By setting the melting point of the adhesive within the above range, a high adhesive force can be exhibited before heating, and the adhesive can be easily melted or softened even with a small amount of heating. The melting point of the adhesive can be adjusted by selecting the type of the resin that is the main component of the adhesive, the content of the tackifier resin in the adhesive, the gel fraction, etc. The melting point of the adhesive can be the temperature of the endothermic peak accompanying melting measured using differential scanning calorimetry (DSC).

[0050] <<<Pressure - sensitive adhesive>>> The pressure - sensitive adhesive is an adhesive that adheres by applying pressure at room temperature for a short time. The pressure - sensitive adhesive is also called a tackifier. The pressure - sensitive adhesive has tackiness at room temperature. There is no particular limitation on the pressure - sensitive adhesive, and a known pressure - sensitive adhesive can be appropriately selected according to the purpose. For example, acrylic - type pressure - sensitive adhesives (acrylic - type tackifiers), urethane - type pressure - sensitive adhesives (urethane - type tackifiers), rubber - type pressure - sensitive adhesives such as synthetic rubber - type pressure - sensitive adhesives and natural rubber - type pressure - sensitive adhesives (rubber - type tackifiers), silicone - type pressure - sensitive adhesives (silicone - type tackifiers), etc. can be mentioned. etc. can be mentioned.

[0051] The pressure-sensitive adhesive may be in a form containing a thermoplastic resin, or may be in a form containing a resin that does not contain a thermoplastic resin and does not have thermoplasticity. When the pressure-sensitive adhesive is in a form containing a thermoplastic resin, the pressure-sensitive adhesive melts or softens by heating, the adhesive force of the pressure-sensitive adhesive decreases, and the intermediate layer A becomes peelable. When the pressure-sensitive adhesive is in a form containing a resin that does not contain a thermoplastic resin and does not have thermoplasticity, by using it in combination with at least one of the hot-melt adhesive and the melt-softening layer, the hot-melt adhesive or the melt-softening layer melts by heating, and the intermediate layer A becomes peelable.

[0052] The acrylic pressure-sensitive adhesive contains an acrylic resin, and further contains other components such as a tackifier resin, a crosslinking agent, and an antioxidant as required. The urethane pressure-sensitive adhesive contains a urethane resin, and further contains other components such as a tackifier resin, a crosslinking agent, and an antioxidant as required. The rubber pressure-sensitive adhesive contains a rubber material such as a styrene resin, and further contains other components such as a tackifier resin, a crosslinking agent, and an antioxidant as required. The silicone pressure-sensitive adhesive contains a silicone resin, and further contains other components such as a tackifier resin, a crosslinking agent, and an antioxidant as required.

[0053] <<<Hot-melt adhesive>>> The hot-melt adhesive is a thermoplastic adhesive that is solid at room temperature but liquefies by heating and melting, is applied to an adherend, and forms a bond by cooling and solidifying. The hot-melt adhesive can be dissolved in a solvent, applied, dried and solidified to form a film, and a bonding state can be formed by applying heat when bonding to an adherend. The hot-melt adhesive usually does not have tackiness at room temperature or has lower tackiness than a pressure-sensitive adhesive. The hot-melt adhesive contains a thermoplastic resin, and further contains other components such as a tackifier resin, a crosslinking agent, and an antioxidant as required.

[0054] Examples of the hot-melt adhesive include rubber-based hot-melt adhesives based on ethylene-vinyl acetate copolymer (EVA)-based hot-melt adhesives, polyolefin-based hot-melt adhesives, polyamide-based hot-melt adhesives, polyurethane-based hot-melt adhesives, acrylic-based hot-melt adhesives, polyester-based hot-melt adhesives, styrene-based thermoplastic elastomers, and the like.

[0055] - Resin - Examples of the resin (base polymer) that can be used as the main component of the pressure-sensitive adhesive and the hot-melt adhesive include urethane resins such as polyurethane (PU) and thermoplastic polyurethane (TPU); polycarbonate (PC); vinyl chloride resins such as polyvinyl chloride (PVC) and vinyl chloride-vinyl acetate copolymer resin; acrylic resins such as polyacrylic acid, polymethacrylic acid, methyl polyacrylate, polymethyl methacrylate (PMMA), ethyl polymethacrylate, and acrylic polymers obtained by polymerizing one or more (meth)acrylic monomers; polyester resins such as polyethylene terephthalate (PET), polybutylene terephthalate, polytrimethylene terephthalate, polyethylene naphthalate, and polybutylene naphthalate; polyamide resins such as Nylon (registered trademark); polystyrene resins such as polystyrene (PS), imide-modified polystyrene, acrylonitrile-butadiene-styrene (ABS) resin, imide-modified ABS resin, styrene-acrylonitrile copolymer (SAN) resin, and acrylonitrile-ethylene-propylene-diene-styrene (AES) resin; olefin resins such as polyethylene (PE) resin, polypropylene (PP) resin, and cycloolefin resin; cellulose resins such as nitrocellulose and cellulose acetate; silicone resin; thermoplastic resins such as fluorine-based resins, styrene thermoplastic elastomers, olefin thermoplastic elastomers, vinyl chloride thermoplastic elastomers, acrylic thermoplastic elastomers, urethane thermoplastic elastomers, ester thermoplastic elastomers, amide thermoplastic elastomers, and the like. These may be used alone or in combination of two or more.

[0056] Among these, thermoplastic resins are preferred, and thermoplastic elastomers such as acrylic resins, urethane resins, polyester resins, styrene thermoplastic elastomers, olefin thermoplastic elastomers, vinyl chloride thermoplastic elastomers, acrylic thermoplastic elastomers, ester thermoplastic elastomers, urethane thermoplastic elastomers, and amide thermoplastic elastomers are more preferred, and styrene thermoplastic elastomers are particularly preferred.

[0057] Examples of the styrene thermoplastic elastomer include styrene-based AB-type diblock copolymers such as styrene-ethylene-butylene copolymer (SEB); styrene-butadiene-styrene copolymer (SBS), hydrogenated product of SBS (styrene-ethylene-butylene-styrene copolymer (SEBS)), styrene-isoprene-styrene copolymer (SIS), hydrogenated product of SIS (styrene-ethylene-propylene-styrene copolymer (SEPS)), styrene-isobutylene-styrene copolymer (SIBS), etc. of styrene-based ABA-type triblock copolymers; styrene-butadiene-styrene-butadiene (SBSB), etc. of styrene-based ABAB-type tetrablock copolymers; styrene-butadiene-styrene-butadiene-styrene (SBSBS), etc. of styrene-based ABABA-type pentablock copolymers; styrene-based multiblock copolymers having more than these AB repeating units; hydrogenated products obtained by hydrogenating ethylenic double bonds of styrene-based random copolymers such as styrene-butadiene rubber (SBR); and the like. These may be used alone or in combination of two or more. As the styrene-based thermoplastic elastomer, commercially available products may be used.

[0058] The weight average molecular weight of the 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. By setting it within the above range, it is easy to adjust the storage elastic modulus and loss tangent of the adhesive (adhesive layer) within a desired range, and melting or softening of the adhesive by heating becomes easy. The method for measuring the weight average molecular weight can be the same as the method for measuring the weight average molecular weight of the acrylic polymer described later.

[0059] The thermoplastic elastomer may be one or more triblock copolymers, one or more diblock copolymers, or a mixture of triblock copolymers and diblock copolymers. Among them, since the adhesive exhibits appropriate cohesive force, has good adhesive force at normal temperature before heating, and can be easily melted or softened by heating, it is preferable that the thermoplastic elastomer contains at least a diblock copolymer. The content of the diblock copolymer in the thermoplastic elastomer is preferably in the range of 10% by mass to 100% by mass, more preferably in the range of 10% by mass to 90% by mass, even more preferably in the range of 15% by mass to 80% by mass, and even more preferably in the range of 20% by mass to 75% by mass because of the excellent balance between adhesiveness at normal temperature and meltability or softening property by heating.

[0060] Also, the thermoplastic resin that is the main component of the adhesive is preferably a polyester resin. It may be a crystalline polyester resin or an amorphous polyester resin.

[0061] Also, the thermoplastic resin that is the main component of the adhesive is preferably an acrylic resin. As the acrylic resin, an acrylic polymer (acrylic polymer) obtained by polymerizing a monomer component containing a (meth)acrylic acid ester monomer can be used. The acrylic polymer may be a homopolymer of a (meth)acrylic acid ester monomer or a copolymer of a (meth)acrylic acid ester monomer and other monomers. Among them, a copolymer is preferably used. Note that (meth)acrylic means acrylic or methacrylic. (meth)acrylate means acrylate or methacrylate.

[0062] Examples of the (meth)acrylic acid ester monomer constituting the acrylic polymer include (meth)acrylic acid esters having 1 to 14 carbon atoms such as methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, isopropyl (meth)acrylate, n-butyl (meth)acrylate, sec-butyl (meth)acrylate, t-butyl (meth)acrylate, isobutyl (meth)acrylate, n-hexyl (meth)acrylate, cyclohexyl (meth)acrylate, n-octyl (meth)acrylate, isooctyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, isononyl (meth)acrylate, isodecyl (meth)acrylate, lauryl (meth)acrylate, etc. Among them, it is preferable to contain a (meth)acrylic acid alkyl ester monomer having an alkyl chain with 1 to 9 carbon atoms, more preferably to contain a (meth)acrylic acid alkyl ester monomer having an alkyl chain with 2 to 9 carbon atoms, and even more preferably to contain a (meth)acrylic acid alkyl ester monomer having an alkyl chain with 4 to 9 carbon atoms because it is easier to adjust the storage elastic modulus and loss tangent of the adhesive (adhesive layer) to a desired range. It is even more preferable to contain an acrylic acid alkyl ester monomer having an alkyl chain with 4 to 9 carbon atoms. Examples of the acrylic acid alkyl ester monomer having an alkyl chain with 4 to 9 carbon atoms include n-butyl acrylate, isooctyl acrylate, 2-ethylhexyl acrylate, isononyl acrylate, etc. The acrylic polymer preferably contains one or more of these as constituent units from the group consisting of them.

[0063] The content of the (meth)acrylic acid ester monomer is preferably in the range of 70 to 99.9% by mass, more preferably in the range of 80 to 99% by mass, and even more preferably in the range of 90 to 97% by mass in the total amount of the monomer components constituting the acrylic polymer, because it is easier to adjust the storage elastic modulus and loss tangent of the adhesive (adhesive layer) to a desired range.

[0064] The acrylic polymer preferably contains, as a (meth)acrylic monomer, a (meth)acrylic monomer having a polar group as a constituent unit in addition to the above-described (meth)acrylic acid ester monomer. Examples of the polar group include a hydroxyl group, a carboxyl group, an amide group, and polar groups other than these groups.

[0065] Examples of the (meth)acrylic monomer having a hydroxyl group include 2-hydroxyethyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, 6-hydroxyhexyl (meth)acrylate, hydroxypropyl (meth)acrylate, caprolactone-modified (meth)acrylate, polyethylene glycol mono(meth)acrylate, polypropylene glycol mono(meth)acrylate, and the like. Among these, it is preferable to use 2-hydroxyethyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, or 6-hydroxyhexyl (meth)acrylate.

[0066] Examples of the (meth)acrylic monomer having a carboxyl group include acrylic acid, methacrylic acid, itaconic acid, maleic acid, crotonic acid, a dimer of acrylic acid or methacrylic acid, ethylene oxide-modified succinic acid acrylate, and the like. Among these, it is preferable to use acrylic acid.

[0067] Examples of the (meth)acrylic monomer having an amide group include N-vinyl-2-pyrrolidone, N-vinylcaprolactam, acryloylmorpholine, acrylamide, N,N-dimethylacrylamide, 2-(perhydrophthalimido-N-yl)ethyl acrylate, and the like. Among these, it is preferable to use N-vinyl-2-pyrrolidone, N-vinylcaprolactam, or acryloylmorpholine.

[0068] Examples of the vinyl monomer having other polar groups include vinyl acetate, acrylonitrile, maleic anhydride, itaconic anhydride, and the like.

[0069] Among the (meth)acrylic monomers having a polar group, it is preferable to contain at least one of a (meth)acrylic monomer having a hydroxyl group and a (meth)acrylic monomer having a carboxyl group. This is because when the crosslinking agent described later is used in combination, a crosslinked structure can be formed between the hydroxyl group or carboxyl group and the crosslinking agent, and it becomes possible to adjust the storage elastic modulus of the adhesive (adhesive layer).

[0070] The content of the (meth)acrylic monomer having a polar group is preferably in the range of 0.1% by mass to 20% by mass, more preferably in the range of 1% by mass to 13% by mass, and even more preferably in the range of 1.5% by mass to 8% by mass in the total amount of the monomer components constituting the acrylic polymer. This is because it becomes easier to adjust the storage elastic modulus and loss tangent of the adhesive (adhesive layer) to a desired range.

[0071] The acrylic polymer preferably has a weight average molecular weight of 400,000 to 1,400,000, more preferably 600,000 to 1,200,000, and even more preferably 650,000 to 1,100,000. This is because it becomes easier to adjust the storage elastic modulus and loss tangent of the adhesive (adhesive layer) to a desired range.

[0072] The weight average molecular weight can be measured by gel permeation chromatography (GPC). More specifically, it can be determined by measuring under the following GPC measurement conditions in terms of polystyrene conversion value using "SC8020" manufactured by Tosoh Corporation as the GPC measurement device. (GPC measurement conditions) · Sample concentration: 0.5% by mass (tetrahydrofuran solution) · Sample injection volume: 100 μL · Eluent: Tetrahydrofuran (THF) · Flow rate: 1.0 mL / min · Column temperature (measurement temperature): 40 °C · Column: "TSKgel GMHHR-H" manufactured by Tosoh Corporation · Detector: Differential refractometer

[0073] The content ratio of the resin, which is the main component of the adhesive, is preferably 50% by mass or more, more preferably 70% by mass or more, still more preferably 90% by mass or more, even more preferably 98% by mass or more, and most preferably 99% by mass or more in 100% by mass of the total solid content of the adhesive. When the adhesive contains the heating element described above, it means the content ratio in the total solid content of the adhesive excluding the content of the heating element.

[0074] When the adhesive contains, in addition to the resin as the main component, a tackifier resin described later, the total content ratio of the resin as the main component and the tackifier resin is preferably 50% by mass or more, more preferably 70% by mass or more, still more preferably 90% by mass or more, even more preferably 98% by mass or more, and most preferably 99% by mass or more in 100% by mass of the total solid content of the adhesive. When the adhesive contains the heating element described above, it means the content ratio in the total solid content of the adhesive excluding the content of the heating element.

[0075] -Other Components- Examples of other components that can be used in the pressure-sensitive adhesive and hot-melt adhesive include, for example, tackifier resins, crosslinking agents, antioxidants, thermally expandable fillers, solvents, infrared absorbers, ultraviolet absorbers, fillers; fibers made of glass or plastic; fillers such as balloons, beads, and metal powders; pigments, thickeners, and the like.

[0076] The pressure-sensitive adhesive and the hot-melt adhesive may be of a heat-foaming type that can be foamed and / or expanded by heating, but it is preferably of a non-heat-foaming type that does not foam and / or expand by heating. Even when it does not contain components (expansion-expressing components) such as thermally expandable fillers and foaming agents that foam and / or expand within the adhesive layer, it can be peeled off by melting or softening the resin contained in the adhesive. Further, since the adhesive layer constituting the intermediate layer is of a non-heat-foaming type, it is possible to suppress failures of articles and parts due to gas generated by foaming and damage to articles and parts due to pressure generated by expansion pressing against the adherend. Furthermore, when the adhesive layer is of a heat-foaming type, after long-term use of articles and parts, there may be cases where the foaming agent etc. denatures, deactivates, or is released to the outside and does not foam during disassembly. However, since the adhesive layer is of a non-heat-foaming type, it can be surely disassembled even after long-term use of articles and parts. That the adhesive does not contain components (expansion-expressing components) that foam and / or expand means that the content relative to 100 parts by mass of the base polymer of the adhesive is less than 1 part by mass.

[0077] --Adhesion-imparting resin-- In the above adhesive, an adhesion-imparting resin may be used to adjust the strong adhesiveness of the obtained adhesive layer. The adhesion-imparting resin is not particularly limited and can be appropriately selected according to the purpose. For example, rosin-based adhesion-imparting resins, polymerized rosin-based adhesion-imparting resins, polymerized rosin ester-based adhesion-imparting resins, rosin phenol-based adhesion-imparting resins, stabilized rosin ester-based adhesion-imparting resins, disproportionated rosin ester-based adhesion-imparting resins, hydrogenated rosin ester-based adhesion-imparting resins, terpene-based adhesion-imparting resins, terpene phenol-based adhesion-imparting resins, aliphatic (petroleum resin)-based adhesion-imparting resins, C5 / C9 petroleum-based adhesion-imparting resins, (meth)acrylate-based adhesion-imparting resins, etc. can be mentioned.

[0078] Also, as the adhesion-imparting resin, in addition to those described above, an adhesion-imparting resin that is liquid at room temperature can also be used. Examples of the liquid adhesion-imparting resin include process oil, polyester-based adhesion-imparting resins, and low-molecular-weight liquid rubbers such as polybutene.

[0079] Since the content of the tackifier resin in the adhesive can improve the adhesiveness of the adhesive at room temperature and exhibit heat durability, it is preferably used in the range of 1 to 150 parts by mass, more preferably in the range of 10 to 150 parts by mass, still more preferably in the range of 15 to 100 parts by mass, and even more preferably in the range of 50 to 100 parts by mass with respect to 100 parts by mass of the base polymer.

[0080] --Crosslinking agent-- In the adhesive, a crosslinking agent may be used for the purpose of improving the cohesion of the obtained adhesive layer. There is no particular limitation on the crosslinking agent, and it can be appropriately selected according to the purpose. For example, isocyanate-based crosslinking agents, epoxy-based crosslinking agents, aziridine-based crosslinking agents, polyvalent metal salt-based crosslinking agents, metal chelate-based crosslinking agents, keto-hydrazide-based crosslinking agents, oxazoline-based crosslinking agents, carbodiimide-based crosslinking agents, silane-based crosslinking agents, glycidyl(alkoxy)epoxysilane-based crosslinking agents, etc. can be mentioned.

[0081] The content of the crosslinking agent contained in the adhesive can be an amount such that the adhesive falls within the range of the gel fraction described later, and can be set as appropriate.

[0082] --Antioxidant-- There is no particular limitation on the antioxidant, and it can be appropriately selected according to the purpose. For example, phenolic antioxidants, amine-based antioxidants, carbodiimide-based antioxidants can be mentioned.

[0083] --Solvent-- There is no particular limitation on the solvent, and the solvent usually used in the adhesive composition can be appropriately selected according to the purpose. For example, organic solvents such as toluene, xylene, ethyl acetate, butyl acetate, acetone, methyl ethyl ketone, hexane; water or an aqueous solvent mainly composed of water, etc. can be mentioned. In the adhesive layer, it is assumed that the solvent is usually not contained, but residual solvent may be contained.

[0084] -Adhesive- When the adhesive contains the resin and the crosslinking agent which are the above-described main components, the gel fraction of the adhesive is preferably 0 mass% to 80 mass% because the adhesive can be sufficiently melted and / or softened even when the heating time is short. Among the above-described ranges, since the initial tackiness of the adhesive layer is good and a good holding force can be exhibited even in a high-temperature environment, the gel fraction is more preferably 10 mass% to 65 mass%, and even more preferably 15 mass% to 55 mass%. Particularly, when the adhesive is a pressure-sensitive adhesive, it is preferable that it is within the range of the gel fraction. On the other hand, among the above-described ranges, since the easy disassembly property by heating is good, the gel fraction is more preferably 0 mass% to 60 mass%, and even more preferably 0 mass% to 40 mass%. Especially, when the adhesive is a hot-melt adhesive, it is preferable that it is within the range of the gel fraction.

[0085] The gel fraction of the adhesive is obtained by forming a coating film of the adhesive, immersing the coating film in toluene, measuring the mass of the insoluble matter remaining after standing for 24 hours after drying, and expressing it as a percentage with respect to the original mass. The gel fraction of the adhesive can be adjusted by the amount of the crosslinking agent and the like.

[0086] [Layer configuration of intermediate layer A] Both surfaces of the intermediate layer A in the adhesive tape may be layers having adhesiveness or layers not having adhesiveness. Among them, it is preferable that both surfaces of the intermediate layer A are layers having pressure-sensitive adhesiveness and / or thermo-adhesiveness. This is because it can be easily laminated and adhered to other layers constituting the adhesive tape such as a heat insulating layer. Further, the intermediate layer A may be a single layer or may be composed of a plurality of layers.

[0087] In addition, when the intermediate layer A is a laminate, the adhesive layers a1 and a2 constituting the intermediate layer A may be collectively described as the adhesive layer a, and the melt-softening layers c1 and c2 may be collectively described as the melt-softening layer c. The adhesive layer a, the heating element b, and the melt-softening layer c will be described in detail later.

[0088] Hereinafter, the intermediate layer A in the adhesive tape will be described with reference to the drawings. The adhesive layers B1, B2, and the heat insulating layer C in the adhesive tape will be described separately.

[0089] [First Aspect] When the intermediate layer A is composed of a plurality of layers, the intermediate layer A in the adhesive tape 10 has, for example, as shown in FIGS. 1A and 1B, a planar heating element b, and adhesive layers a1 and a2 on each surface of the heating element, and is a laminate laminated in the order of adhesive layer a1 / heating element b / adhesive layer a2. That is, the intermediate layer A of the first aspect is a laminate having a heating element b, an adhesive layer a1 in contact with one surface of the heating element b, and an adhesive layer a2 in contact with the other surface of the heating element b. The adhesive layers a1 and a2 may have the same composition as each other or different compositions. At least one of the adhesive layers a1 and a2 may be softened or melted by heating, and both the adhesive layers a1 and a2 may be softened or melted by heating. At least one of the adhesive layers a1 and a2 in contact with the heating element b is melted or softened by heating to reduce the adhesive force, and the intermediate layer A becomes peelable.

[0090] Among them, it is preferable that the adhesive layers a1 and a2 have different compositions from each other. By forming the adhesive layers a1 and a2 with different adhesives, the tendency of the storage elastic modulus and the loss tangent (tan δ) can be changed, and even when both the adhesive layers a1 and a2 can be softened or melted by heating, it is possible to adjust the temperature and the peeling position at the time of disassembly due to the difference in the physical properties of the adhesive layers a1 and a2. This is advantageous.

[0091] Regarding the details of the adhesive for forming the adhesive layer a in the adhesive layer A of the first aspect, it can be the same as the details described in the above item of "<<Adhesive>>".

[0092] At least one of the adhesive layers a1 and a2 is preferably a pressure-sensitive adhesive layer formed of a pressure-sensitive adhesive, and it is more preferable that both the adhesive layers a1 and a2 are pressure-sensitive adhesive layers. Since the pressure-sensitive adhesive layer has tackiness at normal temperature, the adhesive layer a1 and / or the adhesive layer a2, which is a pressure-sensitive adhesive layer, can be easily bonded and adhered to other layers constituting an adhesive tape such as a heat insulating layer.

[0093] Further, at least one of the adhesive layers a1 and a2 may be a hot-melt adhesive layer formed of a hot-melt adhesive, and both the adhesive layers a1 and a2 may be hot-melt adhesive layers. Since the hot-melt adhesive exhibits adhesiveness when heated, the adhesive layer a1 and / or the adhesive layer a2, which is a hot-melt adhesive layer, can be easily bonded and adhered to other layers constituting an adhesive tape such as a heat insulating layer by heating.

[0094] Also, one of the adhesive layers a1 and a2 may be a pressure-sensitive adhesive layer and the other may be a hot-melt adhesive layer.

[0095] In the intermediate layer A of the first aspect, in plan view, it is preferable that the planar heating element b has a pair of extending portions e extending from the outer peripheries of the adhesive layer a1 and the adhesive layer a2 and exposed (see FIGS. 1C and D). There may be two or more extending portions e independently, and the position on the heating element is not particularly limited and can be appropriately selected according to the purpose. The two extending portions e may be located on the same side of the outer periphery of the adhesive layers a1 and a2 (see FIGS. 1D(1) to (3)), or may be located on two different sides respectively (see FIGS. 1C and 1D(4) to (6)).

[0096] The extending portions e are preferably located on two opposing sides of the outer periphery of the adhesive layers a1 and a2 respectively (see FIGS. 1D(4) to (6)), and are preferably located on substantially diagonal lines of the outer periphery of the adhesive layers a1 and a2 respectively (see FIGS. 1D(2) to (7)). Thereby, current can flow through the entire area of the planar heating element b, and the heat generation efficiency can be further improved. Also, when the extending portion e is located on the same side of the outer peripheries of the adhesive layers a1 and a2, it is preferable that the heating element b takes a U-shape, a zigzag shape, etc. in a plan view (see FIGS. 1D(1) to (4), (8)). If the heating element can uniformly heat the in-plane of the adhesive layers a1 and a2, it may be located at adjacent portions on the same side (see FIGS. 1D(3), (8)). Thereby, an electric current can flow through the entire area of the planar heating element b, and the heat generation efficiency can be further enhanced.

[0097] Also, the extending portion e may be provided at three or more positions (see FIG. 1D(9)), and an appropriate pair (two positions) may be selected and the heating element may be energized. The pair of extending portions e of the heating element b function as a pair of terminals for electrically connecting to a power source in the method for disassembling an article described later, and it becomes possible to easily energize the heating element b.

[0098] As the length of the extending portion, from the viewpoint of facilitating contact with a power source or a heat generation source, 1 mm to 50 mm is preferable, and 2 mm to 25 mm is more preferable. Each extending portion may be bent in a direction different from the surface direction of the adhesive tape. For example, when the adherends are in a bonded state, the extending portion is bent and stored in a direction perpendicular to the surface direction of the adhesive tape. When attempting to release the bonding between the adherends (during disassembly), the extending portion may be bent again in the surface direction so that the extending portion contacts a power source or a heat generation source.

[0099] When the intermediate layer A is a laminate composed of a plurality of layers, the average thickness of each of the adhesive layers a1 and a2 can be appropriately selected according to the purpose without particular limitation, but is preferably 5 μm to 200 μm, more preferably 10 μm to 150 μm, and even more preferably 20 μm to 100 μm. The average thickness of each of the adhesive layers a1 and a2 in the second aspect described later can also be defined in the same manner. When the intermediate layer A is a laminate composed of a plurality of layers, the total thickness of the intermediate layer A can be appropriately selected according to the purpose without particular limitation, but is preferably 15 μm to 500 μm, more preferably 30 μm to 400 μm, and even more preferably 50 μm to 300 μm. The total thickness of the intermediate layer A in the second aspect described later can also be defined in the same manner.

[0100] [Second Aspect] Also, as shown in FIG. 2, the intermediate layer A in the adhesive tape 20 may be an aspect in which it is a laminate laminated in the order of the adhesive layer a1 / the heating element b / the melt-softening layer c. Alternatively, the intermediate layer A is a laminate laminated in the order of the melt-softening layer c / the heating element b / the adhesive layer a2; a laminate laminated in the order of the adhesive layer a1 / the heating element b / the melt-softening layer c / the adhesive layer a2; a laminate laminated in the order of the adhesive layer a1 / the melt-softening layer c / the heating element b / the adhesive layer a2; or an aspect in which it is a laminate laminated in the order of the adhesive layer a1 / the melt-softening layer c1 / the heating element b / the melt-softening layer c2 / the adhesive layer a2.

[0101] That is, the intermediate layer A of the second aspect has a heating element, one or two or more adhesive layers a, and a melt-softening layer c. As an example of the intermediate layer A of the second aspect, a laminate having a heating element b, an adhesive layer a disposed on one surface of the heating element b, and a melt-softening layer c disposed on the other surface of the heating element b can be mentioned. Further, as another example of the intermediate layer A of the second aspect, a laminate having a heating element b, an adhesive layer a1 disposed on one surface of the heating element b, an adhesive layer a2 disposed on the other surface of the heating element b, and a melt-softening layer c disposed on at least one of between the heating element b and the adhesive layer a1 and between the heating element b and the adhesive layer a2 can be mentioned.

[0102] At least the molten softening layer c in the intermediate layer A is melted or softened by heating so that the intermediate layer A can be peeled off. In this case, each of the adhesive layer a1 and the adhesive layer a2 may contain an adhesive that is melted or softened by heating, or may not contain an adhesive that is melted or softened by heating. Also, the adhesive layer a1 and the adhesive layer a2 may have the same composition as each other, or may have different compositions. In plan view, it is preferable that the planar heating element b has a pair of extending portions extending from the outer peripheries of the adhesive layer a1, the adhesive layer a2, and the molten softening layer c and exposed. Details of the extending portions are the same as the details of the extending portions of the planar heating element b in the intermediate layer A of the first aspect described above.

[0103] <<Adhesive layer a>> In the intermediate layer A of the second aspect, it is preferable that the adhesive layer a is formed of a pressure-sensitive adhesive or a hot-melt adhesive. Details of the adhesive forming the adhesive layer a can be the same as the details described in the item of "<<Adhesive>>" described above.

[0104] In the intermediate layer A of the second aspect, since the molten softening layer is a layer that is melted or softened by heating, the adhesive layer a may be melted or softened by heat resistance, or may not be melted or softened, but it is preferable to be melted or softened.

[0105] In the intermediate layer A of the second aspect, it is preferable that at least one of the adhesive layers a1 and a2 is a pressure-sensitive adhesive layer formed of a pressure-sensitive adhesive, and it is more preferable that both the adhesive layers a1 and a2 are pressure-sensitive adhesive layers. Since the pressure-sensitive adhesive layer has tackiness at normal temperature, the adhesive layer a1 and / or the adhesive layer a2, which is a pressure-sensitive adhesive layer, can be easily bonded and adhered to other layers constituting an adhesive tape such as a heat insulating layer at normal temperature.

[0106] Further, at least one of the adhesive layers a1 and a2 may be a hot melt adhesive layer formed of a hot melt adhesive, and both the adhesive layers a1 and a2 may be hot melt adhesive layers. Since the hot melt adhesive exhibits adhesiveness when heated, the adhesive layer a1 and / or the adhesive layer a2, which is a hot melt adhesive layer, can be easily bonded to other layers constituting an adhesive tape such as a heat insulating layer by heating and firmly adhered.

[0107] Also, one of the adhesive layers a1 and a2 may be a pressure-sensitive adhesive layer, and the other may be a hot melt adhesive layer.

[0108] <<Melting and softening layer>> The melting and softening layer is a layer that melts or softens by heating. The melting and softening layer is not particularly limited as long as it can provide adhesion between the adhesive layer and the heating element and can ensure the desired adhesive strength between adherends in the article described below. A resin layer that melts or softens by heat can be appropriately selected according to the purpose. Examples include a thermoplastic resin film, a resin layer in which particles having a lower softening point than the matrix resin are dispersed in the matrix resin, and a resin layer in which particles having a softening point are dispersed in a matrix resin having no softening point. Examples of the thermoplastic resin used for the thermoplastic resin film include polyolefin resins such as low-density polyethylene (LDPE), medium-density polyethylene (MDPE), polypropylene (PP), and linear low-density polyethylene (LLDPE); ethylene copolymer resins such as ethylene-vinyl acetate copolymer (EVA), ethylene-acrylic acid copolymer (EAA), and ethylene-methacrylic acid copolymer (EMAA); polyester resins such as crystalline polyester and amorphous polyester; and urethane resins. Also, the thermoplastic resins and thermoplastic elastomers described in the adhesive can be used.

[0109] When it is difficult to adjust the temperature at which the thermoplastic film formed of a single resin constituting the thermoplastic film melts or softens, the thermoplastic film may contain additives such as a plasticizer and a tackifier resin.

[0110] The melting and softening layer preferably has a melting point of 70°C or higher and 150°C or lower, more preferably 75°C or higher and 130°C or lower, and even more preferably 80°C or higher and 110°C or lower. By setting the melting point of the melting and softening layer within the above range, it can be easily melted or softened even with a small amount of resistive heating by energization. The melting point of the melting and softening layer can be adjusted by selecting the type, composition, etc. of the resin (especially thermoplastic resin) that is the main component of the melting and softening layer. The melting point (melting temperature) of the melting and softening layer can be the temperature of the endothermic peak accompanying melting measured using differential scanning calorimetry (DSC).

[0111] The storage elastic modulus G measured by the dynamic viscoelastic spectrum of the melting and softening layer at 1 Hz and 23°C 23 is preferably 1.0×10 3 Pa to 1.0×10 9 Pa from the viewpoint of being well fixed to the adjacent layer in the normal state, more preferably 5.0×10 3 Pa to 5.0×10 8 Pa, and particularly preferably 1.0×10 4 Pa to 1.0×10 8 Pa. The storage elastic modulus G of the melting and softening layer 23 can be measured by the same method as the measurement method of the storage elastic modulus G of the adhesive (adhesive layer). 23

[0112] The temperature at which the storage elastic modulus of the melting and softening layer is less than 1.0×10 5 Pa preferably exists in the temperature range of 80°C to 200°C, more preferably the temperature at which the storage elastic modulus of the melting and softening layer is less than 1.0×10 4 Pa exists in the temperature range of 80°C to 200°C, and even more preferably the temperature at which the storage elastic modulus of the melting and softening layer is less than 1.0×10 3 Pa exists in the temperature range of 80°C to 200°C. The storage elastic modulus of the melting and softening layer is less than 1.0×10 5 ​The temperature below Pa exists in the temperature range of 80°C to 200°C. When the molten softening layer reaches this temperature due to heat reception from the heating element, it is advantageous in that it can be melted or softened to cause peeling within the layer of the molten softening layer or at the interface between these layers and the adjacent layers. The storage elastic modulus of the molten softening layer can be measured in the same manner as the measurement method of the storage elastic modulus of the adhesive layer described above.

[0113] When having the molten softening layer, there is no particular limitation on the average thickness of the molten softening layer, and it can be appropriately selected according to the purpose. However, 5 μm to 200 μm is preferable, 10 μm to 150 μm is more preferable, and 20 μm to 100 μm is even more preferable.

[0114] [Third Aspect] When the intermediate layer A is a single layer, the intermediate layer A in the adhesive tape 30 may be a single layer composed of the heating element b and the adhesive layer a3 containing an adhesive (see FIG. 3). The heating element b may be in a mesh shape, or may be in a form in which particles or fibers made of the heating element are dispersed, and can be appropriately selected according to the heating means used. The adhesive layer a3 preferably contains at least one of the pressure-sensitive adhesive containing the thermoplastic resin and the hot-melt adhesive as the adhesive. The adhesive layer a3 melts or softens by heating, resulting in a decrease in adhesive force, and the intermediate layer A becomes peelable.

[0115] In the intermediate layer A of the third aspect, the adhesive layer a3 is preferably formed by a pressure-sensitive adhesive or a hot-melt adhesive. Details of the adhesive forming the adhesive layer a3 can be the same as the details described in the item of "<<Adhesive>>" above. Also, in the intermediate layer A of the third aspect, details of the heating element b contained in the adhesive layer a3 can be the same as the details described in the item of "<<Heating Element>>" above.

[0116] In the intermediate layer A of the third aspect, it is preferable that both surfaces of the intermediate layer (the outermost surfaces facing each other in the thickness direction of the intermediate layer) have adhesiveness (pressure-sensitive adhesiveness and / or heat adhesiveness) respectively.

[0117] In the intermediate layer A of the third aspect, the adhesive for forming the adhesive layer a3 may be a pressure-sensitive adhesive. That is, the adhesive layer A may be a pressure-sensitive adhesive layer a3 containing a heating element. This is because both surfaces of the adhesive layer A can have tackiness at room temperature and can be bonded to other layers constituting the adhesive tape of the present invention, such as a heat insulation layer.

[0118] Also, in the adhesive layer A of the third aspect, the adhesive for forming the adhesive layer a3 may be a hot melt adhesive. That is, the intermediate layer A may be a hot melt adhesive layer a3 containing a heating element. Since the hot melt adhesive exhibits adhesiveness when heated, the adhesive layer A, which is a hot melt adhesive layer, can be easily bonded and adhered to other layers constituting the adhesive tape, such as a heat insulation layer, by heating.

[0119] The total thickness of the intermediate layer A when the intermediate layer A is a single layer is not particularly limited and can be appropriately selected according to the purpose. However, 15 μm to 500 μm is preferable, 30 μm to 400 μm is more preferable, and 50 μm to 300 μm is even more preferable.

[0120] <Adhesive layers B1 and B2> The adhesive layer B1 contains at least the adhesive B1 and, if necessary, further contains other components. The adhesive layer B1 is disposed on one surface side of the intermediate layer A. The adhesive layer B2 contains at least the adhesive B2 and, if necessary, further contains other components. The adhesive layer B2 is disposed on the other surface side of the intermediate layer A. At least one of the adhesive layer B1 and the adhesive layer B2 may be a heat insulation layer C having further heat insulation properties. The adhesives B1 and B2 are not particularly limited, and known adhesives or general-purpose adhesives can be appropriately selected according to the purpose. Examples include pressure-sensitive adhesives. As the pressure-sensitive adhesive, the pressure-sensitive adhesive described in the intermediate layer A can be appropriately selected. The adhesives B1 and B2 may have the same composition or different compositions from each other.

[0121] As the other components, the other components described in the intermediate layer A can be appropriately selected.

[0122] The average thickness of the adhesive layer B1 and the adhesive layer B2 is not particularly limited and can be appropriately selected according to the purpose. However, 5 μm to 200 μm is preferable, 10 μm to 150 μm is more preferable, and 15 μm to 100 μm is even more preferable.

[0123] <Heat insulation layer C> As the heat insulation layer C, there is no particular limitation as long as it is a layer having heat insulation properties, and it can be appropriately selected according to the purpose. For example, there are planar layers having voids (hollows) in the layer such as a foam layer, a hollow-containing layer, a hollow particle-containing layer, etc. Among these, a foam layer is preferable from the viewpoints of flexibility, adhesion followability, etc.

[0124] The heat insulation layer C preferably has a thermal conductivity of 0.15 W / m·K or less as measured according to ASTM-D5470. Among them, 0.1 W / m·K or less is preferable, 0.08 W / m·K or less is more preferable, and 0.06 W / m·K or less is even more preferable. When the thermal conductivity of the heat insulation layer C is within the above range, the heat conduction from the heating element to the adherend can be shielded, and the heat generated by the heating element can be efficiently used for the melting or softening of the intermediate layer A.

[0125] When the heat insulation layer C is a foam layer, the foam layer may be a closed-cell foam or an open-cell foam. As the foam layer, polyolefin foams made of polyethylene, polypropylene, ethylene-propylene copolymer polymers, ethylene-vinyl acetate copolymer polymers, etc., polyurethane foams, rubber foams made of acrylic rubbers and other elastomers, etc. can be used. Among them, polyolefin foams can be preferably used because of their excellent form retention at high temperatures.

[0126] When at least one of the adhesive layer B1 and the adhesive layer B2 is a heat insulation layer C having further heat insulation properties, examples of the heat insulation layer C include an adhesive layer containing voids, an adhesive layer containing hollow particles, etc. Alternatively, the heat insulation layer C is disposed in at least one of between the intermediate layer A and the adhesive layer B1 and between the intermediate layer A and the adhesive layer B2. It is preferable that the heat insulation layer C is disposed between both the intermediate layer A and the adhesive layer B1 and between the intermediate layer A and the adhesive layer B2.

[0127] Alternatively, it is preferable that the heat insulation layer C has a first region and a second region having a lower thermal conductivity than the first region. The first region is not particularly limited and can be appropriately selected according to the purpose, and examples include the adhesive, resin, etc. Examples of the resin include polyolefin resins such as polyethylene and polypropylene; polyester resins such as polyethylene terephthalate, polyethylene naphthalate, and polybutylene terephthalate; acrylic resins; styrene resins such as polystyrene; urethane resins such as polyurethane; polyvinyl chloride-based resins; olefin-based elastomers; acrylic-based elastomers; styrene-based elastomers; butyl-based elastomers; rubber-based resins such as natural rubber. The second region is not particularly limited and can be appropriately selected according to the purpose, and may be a gas such as air or an inert gas, may be hollow particles containing the gas, may be a liquid or solid having a low thermal conductivity, or may be a filler containing the liquid or solid. Among these, a gas and hollow particles containing the gas are preferable.

[0128] The average thickness of the heat insulation layer C is not particularly limited as long as the desired heat insulation performance can be exhibited, and it can be appropriately selected according to the purpose. However, 15 μm to 1,000 μm is preferable, 30 μm to 500 μm is more preferable, and 50 μm to 200 μm is even more preferable. Further, the porosity of the heat insulation layer C only needs to be able to exhibit the heat insulation performance due to the voids, and 5% to 90% is preferable, 10% to 80% is more preferable, and 20% to 70% is even more preferable. When the thickness and porosity of the heat insulation layer C are within the above ranges respectively, it is advantageous in that the heat insulation effect by the heat insulation layer C can be efficiently exhibited.

[0129] The porosity of the heat insulation layer C indicates the ratio of the voids composed of the gas contained in the heat insulation layer C and the porous cavities (voids) to the heat insulation layer C, and can be calculated by the following method. First, in accordance with JIS K6767, the heat insulation layer whose thickness has been measured in advance is cut into a rectangle of 4 cm × 5 cm and about 15 cm 3 is prepared for a minute, its mass is measured, and the density (X1) is obtained from the mass and volume. Next, the density (X2) is obtained from the density derived from the material of the component constituting the region other than the voids of the heat insulation layer and its blending ratio. When the heat insulation layer is composed of one type of component, the density derived from the material of the component becomes the density (X2). For example, when the heat insulation layer is formed only of an acrylic resin, the density of the acrylic resin becomes the density (X2). Further, when the heat insulation layer is composed of n types of components, the density (X2) can be calculated by the following formula. Density (X2) = (density derived from the material of component 1 × ratio of component 1 in the material of the heat insulation layer) + (density derived from the material of component 2 × ratio of component 2 in the material of the heat insulation layer) + ··· + (density derived from the material of component n × ratio of component n in the material of the heat insulation layer) Note that the total of the ratios of component 1 to component n is 100% by mass. From the obtained density (X1) and density (X2), the value calculated based on the following formula is taken as the porosity. Porosity (%) = {1 - (density X1 / density X2)} × 100

[0130] <Release layer> The adhesive tape may have other layers such as a release layer. The release layer is not particularly limited and can be appropriately selected according to the purpose. For example, glassine 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 acrylate copolymer, a synthetic resin film such as polyester or polypropylene coated with a fluororesin or silicone resin which is a release agent, etc. can be mentioned. The release layer may be provided on one side of the adhesive tape or on both sides.

[0131] [Uses of the Adhesive Tape] Since both sides of the adhesive tape of the present invention, excluding the release liner, function as adhesive surfaces (adhesive faces), an adherend can be bonded to each of the two sides of the adhesive tape, and it can be suitably used for joining adherends to each other. Since the adhesive tape of the present invention can be peeled off by resistance heating, it is used as a resistance heating (electrically heated) peelable tape.

[0132] The adhesive tape of the present invention is not particularly limited, but can be suitably used for adhering a rigid adherend to an adherend and separating adherends from each other. When separating parts during reuse or recycling, the adhesive tape of the present invention can be easily disassembled by heating. Therefore, it can be used for applications in situations where peeling of the adhesive tape is required. For example, it can be suitably used as an adhesive tape for fixing parts of various products in industrial applications such as the electronics, automotive, building materials, OA, and home appliance industries. The working efficiency is also good when separating a large number of parts or peeling a large number of labels during reuse or recycling.

[0133] [Layer Structure of the Adhesive Tape] The layer structure of the adhesive tape will be described with reference to the drawings. As shown in FIGS. 1A and 1B, the adhesive tape 10 has an intermediate layer A, an adhesive layer B1 disposed on one surface side of the intermediate layer A, and an adhesive layer B2 disposed on the other surface side of the intermediate layer A. Heat insulating layers C are provided between the intermediate layer A and the adhesive layer B1 and between the intermediate layer A and the adhesive layer B2, respectively, and it may be an embodiment in which a laminate is formed in the order of adhesive layer B1 / heat insulating layer C1 / intermediate layer A / heat insulating layer C2 / adhesive layer B2. Note that the adhesive tapes 20 and 30 shown in FIGS. 2 and 3 also show an embodiment in which a laminate is formed in the order of adhesive layer B1 / heat insulating layer C1 / intermediate layer A / heat insulating layer C2 / adhesive layer B2, the same as in FIG. 1 except that the layer structure of the intermediate layer A is different. The adhesive layer B1 and the adhesive layer B2 may have the same composition as each other or different compositions. The heat insulating layer C1 and the heat insulating layer C2 may have the same composition as each other or different compositions.

[0134] As shown in FIG. 4, the adhesive tape 40 has an intermediate layer A, an adhesive layer B1 disposed on one surface side of the intermediate layer A, and an adhesive layer B2 disposed on the other surface side of the intermediate layer A. A heat insulating layer C is provided on either one of the intermediate layer A and the adhesive layer B1 and between the intermediate layer A and the adhesive layer B2, and it may be an embodiment in which a laminate is formed in the order of adhesive layer B1 / heat insulating layer C1 / intermediate layer A / adhesive layer B2. Further, it may be an embodiment in which a laminate is formed in the order of adhesive layer B1 / intermediate layer A / heat insulating layer C2 / adhesive layer B2. As the intermediate layer A, any of the first to third embodiments described above can be appropriately selected.

[0135] As shown in FIG. 5, the adhesive tape 50 has an intermediate layer A, an adhesive layer B1 disposed on one surface side of the intermediate layer A, and an adhesive layer B2 disposed on the other surface side of the intermediate layer A, and at least one of the adhesive layer B1 and the adhesive layer B2 may be a heat insulating layer C having further heat insulating properties. The adhesive tape 50 is in a form of a laminate laminated in the order of adhesive layer B1 (= heat insulating layer C1) / intermediate layer A / adhesive layer B2 (= heat insulating layer C2). Further, the adhesive tape may be in a form of a laminate laminated in the order of adhesive layer B1 (= heat insulating layer C1) / intermediate layer A / adhesive layer B2, or may be in a form of a laminate laminated in the order of adhesive layer B1 / intermediate layer A / adhesive layer B2 (= heat insulating layer C2). As the intermediate layer A, any of the first to third embodiments described above can be appropriately selected.

[0136] [Method for manufacturing the adhesive tape] Examples of the method for manufacturing the adhesive tape include coating a composition containing the adhesive B1 on a release sheet and drying it, coating a composition containing the adhesive B2 on a release sheet and drying it, preparing a heat insulating layer C, and sequentially laminating it with each surface of the intermediate layer A. Examples of the method for manufacturing the intermediate layer A include, when the intermediate layer A has a planar heating element or an integrally formed mesh-like heating element, for example, coating a composition containing the adhesive a1 on a release sheet, separately coating a composition containing the adhesive a2 on a release sheet, and after passing through a drying step, sequentially laminating it with each surface of the heating element. When the intermediate layer A has a particulate or fibrous heating element, for example, a method of coating a composition containing a particulate or fibrous heating element and an adhesive on a release sheet and, after passing through a drying step, laminating a release sheet (or an adhesive layer B1, B2, heat insulating layer C, etc.) can be mentioned.

[0137] As the method for manufacturing the heat insulating layer C, a known method can be used according to the type of the heat insulating layer. For example, when the heat insulating layer C is a foam layer, a known method for manufacturing a foam, specifically, a mixture obtained by adding a foaming agent, a crosslinking agent, and, if necessary, additives such as a polyfunctional monomer and a filler to a resin for foam is molded into a predetermined shape, and then crosslinked by irradiating with radiation or heating at a temperature below the decomposition temperature of the foaming agent, and then heating to a temperature above the decomposition temperature of the foaming agent to cause foaming, whereby the foam layer can be manufactured. Note that the crosslinking and the foaming may be performed simultaneously. Also, a commercially available foam may be used as the heat insulating layer. When the heat insulating layer C is a hollow-containing layer, for example, a composition in which a thermal expansion filler or the like is dispersed in a resin is used to form it in a layer shape by a desired method such as extrusion or coating, and a hollow is formed in the layer by foaming the thermal expansion filler or the like, whereby the hollow-containing layer can be manufactured. When the heat insulating layer C is a hollow particle-containing layer, for example, a composition in which hollow particles are dispersed in a resin is formed in a layer shape by a desired method such as extrusion or coating to manufacture the hollow particle-containing layer.

[0138] 2. Article The article of the present invention is an article including at least two adherends and at least including the adhesive tape of the present invention between the two adherends, and the two adherends are adhered via the adhesive tape. As the method for adhering the adherends, there is a method of pasting the adherends on each surface having the adhesiveness of the adhesive tape to bond the two adherends together. The article is not particularly limited and can be appropriately selected according to the purpose, but electronic devices, components incorporated in electronic devices, etc. are preferable. In plan view, it is preferable that the adhesive tape has a pair of extending portions extending from the outer periphery of the adherend.

[0139] <Adhesive tape> Details of the adhesive tape in the article of the present invention are as described in the item of "1. Adhesive tape" already described.

[0140] <Adherend> The adherend may have rigidity or may have flexibility like a film or the like. The adherend is not particularly limited and can be appropriately selected according to the purpose. For example, a metal plate, a metal housing, a metal cover, a glass plate, a plastic plate, etc.; parts having any of these on the adherend surface, etc. may be mentioned. The two adherends adhered via the adhesive tape may be the same as each other or different from each other.

[0141] The article 100 of the present invention includes, for example, as shown in the schematic plan view of FIG. 6A and the schematic cross-sectional view of FIG. 6B, two adherends 90 and an adhesive tape 10 including a laminate in which an adhesive layer B1 / heat insulating layer C1 / intermediate layer A / heat insulating layer C2 / adhesive layer B2 are laminated in this order between the two adherends 90. It is an article in which two adherends 90 are adhered via an adhesive tape 10. In a plan view (FIG. 6A), both ends in the major axis direction of the intermediate layer A extend from the outer periphery of the adherend. Further, both ends in the major axis direction of the planar heating element b extend from the outer peripheries of the adhesive layer a1 and the adhesive layer a2. Both ends of the extended adhesive tape 10 can be used as a pair of terminals for electrically connecting to a power source or an end portion for contacting a heat generation source when the heating means is either resistance heating or heat conduction in the method for disassembling the article described later, and it becomes possible to easily heat the heating element b of the adhesive tape 10. Also, as shown in FIG. 6A, in a plan view, it is advantageous in that the smaller the contact area between the adherend and the adhesive tape, the higher the heat generation efficiency of the heating element and the easier it is to cause a disassembly trigger during heating, so that it is easy to disassemble.

[0142] Also, although not shown, the article of the present invention may be an article including two adherends 90 and any one of the adhesive tapes 10 to 50 shown in FIGS. 1 to 5 between the two adherends 90, and the two adherends 90 are adhered via the adhesive tape.

[0143] In a plan view of the article, the adhesive tape may be adhered over the entire adherend surface which is the surface of the adherend on the adhesive tape side, or the adhesive tape may be adhered to a part of the adherend surface. Among these, as illustrated in FIG. 6A, it is preferable that the adhesive tape 10 is adhered to a part of the adherend surface of the adherend 50. Since 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 starting point of peeling is likely to occur between the adherend and the adhesive tape, which is advantageous in terms of easy peeling.

[0144] As illustrated in FIG. 6A, when the adhesive tape 10 is adhered to a part of the adherend surface of the adherend 50 in a plan view of the article of the present invention, the plan view shape of the adhesive tape 10 in the article may be strip-shaped or linear, or may be a pattern shape.

[0145] Also, in a plan view of the article of the present invention, when the adhesive tape is adhered over the entire adherend surface which is the surface of the adherend on the adhesive tape side, the plan view shape of the planar heating element in the adhesive tape may be the same shape as the plan view shape of the adhesive tape, or may be strip-shaped, linear or pattern-shaped.

[0146] 3. Method for disassembling the article The method for disassembling the article of the present invention is a method for disassembling the article of the present invention or a method for disassembling an article in which two adherends are adhered via the adhesive tape of the present invention, and includes a separation step, and further includes other steps as necessary.

[0147] Details of the article in the disassembly method of the present invention and the adhesive tape used for the article are the same as the details described in the items of the above "2. Article" and the above "1. Adhesive tape".

[0148] <Separation step> The separation step is a step of separating the two adherends by softening or melting the intermediate layer A by heating the heating element.

[0149] The means and method for heating the heating element are not particularly limited and can be appropriately selected according to the purpose. For example, electromagnetic induction heating, infrared heating, microwave heating, heat conduction, resistance heating, etc. may be mentioned. Among these, resistance heating is preferred.

[0150] <<Resistance Heating>> When the heating of the heating element is resistance heating, as the separation step, it is preferable that the intermediate layer A and the power source are electrically connected, the heating element is energized from the power source, and the intermediate layer A is softened or melted by resistance heating to separate the two adherends.

[0151] The power source is not particularly limited and can be appropriately selected according to the purpose. It may be an external power source, or may be the drive power source of the article which is an electronic device or a component built in the electronic device. However, it is preferably the drive power source of the electronic device or a component built in the electronic device. Further, when the article is an electronic device or a component built in the electronic device, and the power source is the drive power source of the electronic device, the separation step is to electrically connect the intermediate layer A and the drive power source and the electric circuit of the electronic device, energize the heating element from the drive power source, and melt or soften the intermediate layer A by resistance heating to separate the two adherends. It is preferably a process.

[0152] As the method of electrically connecting, the intermediate layer A (preferably both ends of the heating element or the extended heating element) and the power source may be electrically connected using known means such as alligator clips. The electric circuit and the means for electrically connecting are preferably formed of a conductive material having a volume resistivity different from that of the material of the heating element in the adhesive tape. Among them, it is more preferably formed of a conductive material having a lower volume resistivity than the heating element. Since the means is formed of a conductive material having a lower volume resistivity than the heating element, when the heating element and the electric circuit are electrically connected and the heating element is energized from the drive power source, it is possible to prevent the electric circuit and the means for electrically connecting from being overheated, while efficiently applying a voltage to the intermediate layer A to enable peeling in a short time. This is advantageous in terms of

[0153] As the method of energization, it can be appropriately selected according to the size of the adhesive tape, the heating element used, etc. For example, a method of applying a voltage of 0.1 V to 200 V until the adhesive layer A melts or softens (for example, for 0.5 seconds to 30 minutes) can be mentioned. For example, as schematically shown in FIG. 7, a simple power source can be used. The intermediate layer A of the adhesive tape and the power source are electrically connected, and a voltage is applied to the heating element to energize it, so that the heating element and its periphery are heated by resistive heating. As a result, the adhesive or any melting / softening layer softens or melts, and the adhesion state is released at the intermediate layer A itself or at a desired position within the intermediate layer A, so that the intermediate layer A can be peeled off, and the adhered adherend can be disassembled.

[0154] The voltage applied to the heating element by energization is not particularly limited, but is preferably 0.1 V or more and 200 V or less, more preferably 0.5 V or more and 150 V or less, and still more preferably 1.0 V or more and 100 V or less. Since the adhesive layer A softens or melts in a short time even when the applied voltage is low, by setting the voltage applied in the separation process within the above range, the article can be disassembled in a short time without applying an excessive voltage, and damage to the article can be prevented. In particular, by applying a voltage that can be applied to small electronic devices and household appliances, these articles can be easily disassembled.

[0155] The current flowing through the heating element is not particularly limited, but is preferably 0.01 A or more and 20 A or less, preferably 0.03 A or more and 15 A or less, preferably 0.05 A or more and 10 A or less, and more preferably 0.1 A or more and 5 A or less. Since the adhesive layer A softens or melts in a short time in the adhesive tape of the present invention, by setting the current applied in the separation process within the above range, a current flowing through general-purpose electronic devices and household appliances can be applied to disassemble the article in a short time, and damage to the article can be prevented. In particular, by applying a current that can be applied to small electronic devices and household appliances, these articles can be easily disassembled.

[0156] The application time of the current is not particularly limited, but it is preferably 0.5 seconds or more and 30 minutes or less, more preferably 0.5 seconds or more and 120 seconds or less, and even more preferably 0.5 seconds or more and 30 seconds or less. By setting the application time within the above range and applying an appropriate voltage, it is possible to disassemble the article in a short time without damaging it.

[0157] <<Electromagnetic induction heating>> When the heating of the heating element is electromagnetic induction heating, the separation step is preferably a step of separating the two adherends by softening or melting the intermediate layer A by electromagnetic induction heating using electromagnetic induction heating means. There is no particular limitation on the electromagnetic induction heating means, and a known electromagnetic induction heating device can be appropriately selected according to the purpose.

[0158] <<Infrared heating and microwave heating>> When the heating of the heating element is either infrared heating or microwave heating, the separation step is preferably a step of separating the two adherends by softening or melting the intermediate layer A by either infrared heating using infrared heating means or microwave heating using microwave heating means. There is no particular limitation on the infrared heating means and the microwave heating means, and a known infrared heating device and a microwave heating device can be appropriately selected according to the purpose.

[0159] <<Heat conduction>> When the heating of the heating element is heat conduction, the separation step is preferably a step of separating the two adherends by bringing the intermediate layer A into contact with a heat source and softening or melting the adhesive layer A by heat conduction. There is no particular limitation on the heat source, and a known heater can be appropriately selected according to the purpose. As the method of heat conduction using the heat source, it can be appropriately selected according to the size of the adhesive tape, the heating element used, etc. For example, a method of bringing them into contact until the intermediate layer A melts or softens at a desired temperature can be mentioned.

Examples

[0160] Hereinafter, the present invention will be described more specifically based on examples, but the present invention is not limited to the following examples. Unless otherwise specified, "parts" refers to "parts by mass" and "%" refers to "% by mass". In addition, the configuration of the adhesive tape shown in the examples and reference examples is the configuration excluding the release liner, and the total thickness of the adhesive tape does not include the thickness of the release liner.

[0161] <Measurement method of physical properties> (Storage elastic modulus G 23 and storage elastic modulus G 100 ) The storage elastic modulus G 23 and storage elastic modulus G 100 of the adhesive layer a formed of the adhesive compositions (P-1) and (P-2) were measured by the following method. Using a viscoelasticity tester (ARES-G2, manufactured by TA Instruments Japan), a test piece was sandwiched between parallel disks with a diameter of 8 mm, which is the measurement part of the tester, and the storage elastic modulus G' was measured 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, and the values at 23°C and 100°C were used. As the test piece, an adhesive layer (adhesive layer) obtained by applying and drying the adhesive composition using an applicator so that the dry thickness was about 2 mm and curing it in an environment of 40°C for 48 hours was used.

[0162] (Measured value of volume resistivity of heating element) The measured values of the volume resistivity of the heating elements used in the examples and reference examples were measured at room temperature of 20°C in accordance with JIS K 7194 using a low resistivity meter (manufactured by Nitto Seiko Analytic Co., Ltd., trade name: "Loresta-AX MCT-T370") and a four-probe probe (manufactured by Nitto Seiko Analytic Co., Ltd., trade name: "ASP probe MCP-TP03P"). The number of measurement points was one-point measurement, and 4.532 was used as the resistivity correction coefficient.

[0163] <Preparation of adhesive composition (P-1)> Styrene-isoprene block copolymer composition a (a mixture of a styrene-isoprene diblock copolymer and a styrene-isoprene triblock copolymer, 24% by mass of the structural unit derived from styrene represented by the following chemical formula (1), and the proportion of the styrene-isoprene diblock copolymer in the total amount of the composition a is 67% by mass) 100 parts by mass, Quintone G115 (a C5 / C9 petroleum resin manufactured by Nippon Zeon Co., Ltd., softening point 115 °C) 40 parts by mass, Pencil D-160 (a polymerized rosin ester resin manufactured by Arakawa Chemical Industries, Ltd., softening point 15 °C to 150 °C) 30 parts by mass, Nisseki Polybutene HV-50 (a polybutene manufactured by JX Nippon Mining & Energy Corporation, pour point -12.5 °C) 5 parts by mass, and an antioxidant (tetrakis-[methylene-3-(3',5'-di-t-butyl-4-hydroxyphenyl)propionate]methane) 1 part by mass are mixed and dissolved in 100 parts by mass of toluene as a solvent to obtain an adhesive composition (P-1).

[0164]

Chemical formula

[0165] <Preparation of Adhesive Composition (P-2)> Into a reaction vessel equipped with a stirrer, a reflux condenser, a nitrogen inlet tube, and a thermometer, 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 part by mass of 4-hydroxybutyl acrylate, and 200 parts by mass of ethyl acetate were charged, and nitrogen bubbling was carried out at room temperature for 1 hour under stirring to obtain a mixture. Next, 2 parts by mass (solid content 1.0% by mass) of a 2,2'-azobis(2-methylbutyronitrile) solution previously dissolved in ethyl acetate was added to the mixture, and the mixture was held at 72°C for 4 hours and then at 75°C for 5 hours under stirring. Next, the obtained mixture was diluted with ethyl acetate and filtered through a 200-mesh wire mesh 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 4.4 in the saturated hydrocarbon group of the alkyl acrylate monomer. To 100 parts by mass of the acrylic copolymer (A-1) solution, 1.0 part by mass of an adduct of tolylene diisocyanate and trimethylolpropane (manufactured by DIC Corporation, "Varnock D-40", isocyanate-based crosslinking agent, solid content 40%, hereinafter referred to as "D-40") was blended as a crosslinking agent to obtain an adhesive composition (P-2).

[0166] (Example 1) <Production of Adhesive Tape> <<Production of Foam Layer>> As the heat insulation layer C, a polyethylene foam layer (thickness 100 μm, porosity 60%) was used.

[0167] <<Production of Intermediate Layer A>> The adhesive composition (P-1) was applied to the release-treated surface of a release liner (a polyethylene terephthalate film with a thickness of 75 μm and one side release-treated) so that the thickness after drying would be 50 μm, and dried at 90°C for 3 minutes to produce an adhesive layer a1.

[0168] Next, the adhesive composition (P-2) was applied to the release-treated surface of a release liner (a polyethylene terephthalate film with a thickness of 75 μm and one side release-treated) so that the thickness after drying would be 50 μm, and dried at 90°C for 3 minutes to produce an adhesive layer a2.

[0169] As the heating element, a nichrome foil with a thickness of 10 μm (manufactured by Takeuchi Metal Foil Co., Ltd., "Nichrome NCH1-H") was used. An adhesive layer a1 cut to a length of 50 mm and an arbitrary width was bonded to a nichrome foil with a length of 100 mm using a hand roller, and positioned so that the nichrome foil extended 25 mm at both ends in the length direction. Similarly, an adhesive layer a2 cut to a length of 50 mm and an arbitrary width was bonded to the opposite surface of the nichrome foil bonded to the adhesive layer a1, and laminated with a roll having a line pressure of 5 kg / cm from the upper surface of the release liner, so that both ends of the nichrome foil extended 25 mm each in the length direction from the outer periphery of the adhesive layer a1 and the adhesive layer a2, and a laminate with a total thickness of 110 μm was created, and then aged in an environment at 40°C for 48 hours. This was cut to a width of 2 mm, and an intermediate layer A was obtained in which the adhesive layer a1 and the adhesive layer a2 had a size of 2 mm × 50 mm in width, the nichrome foil had a size of 2 mm × 100 mm, and the nichrome foil had a pair of extended portions extending from the outer periphery of the adhesive layer a1 and the adhesive layer a2. The volume resistivity of the nichrome foil was 108 μΩ·cm according to the catalog value and 105 μΩ·cm according to the measured value. The intermediate layer A obtained in Example 1 was designated as the intermediate layer (A-1).

[0170] Regarding the viscoelastic parameters of the adhesive layer formed by the adhesive composition (P-1), the storage modulus G at 23°C 23 : 3.E+05, the loss tangent (tanδ) at 23°C: 0.33, the storage modulus G at 100°C 100 : 8.E+04, the loss tangent (tanδ) at 100°C: 0.48, the temperature at which the loss tangent (tanδ) becomes 0.45 or more: 94°C or higher. Regarding the viscoelastic parameters of the adhesive layer formed by the adhesive composition (P-2), the storage modulus G at 23°C 23 : 9.E+04, the loss tangent (tanδ) at 23°C: 0.69, the storage modulus G at 100°C 100 : 2.E+04, the loss tangent (tanδ) at 100°C: 0.33, the temperature at which the loss tangent (tanδ) becomes 0.45 or more: above 150°C.

[0171] <<Fabrication of the laminate of the adhesive layer B1 and the heat insulation layer C>> The adhesive composition (P-2) was applied to the release-treated surface of a release liner (a polyethylene terephthalate film with a thickness of 75 μm and one side release-treated) so that the thickness after drying would be 50 μm, and dried at 90°C for 3 minutes to obtain the adhesive layer B1. After laminating the adhesive layer B1 and the heat insulation layer C (a polyethylene foam layer), it was laminated with a roll having a line pressure of 5 kg / cm from the upper surface of the release liner. By aging this in an environment at 40°C for 48 hours, a laminate (T-2) with the adhesive layer B1 and the heat insulation layer C laminated with a total thickness of 150 μm was obtained. Two laminates (T-2) were fabricated.

[0172] Two laminates (T-2) cut to a length of 50 mm and an arbitrary width were sandwiched so that the foam layers were in contact with both sides of the intermediate layer (A-1), and bonded so that the ends of the adhesive layers a1 and a2 would coincide with the ends of T-2. It was laminated with a roll having a line pressure of 5 kg / cm from the upper surface of the release liner to obtain the adhesive tape of Example 1 with a total thickness of 410 μm.

[0173] The adhesive tape of Example 1 is a laminate in which the layer structure excluding the release liner is laminated in the order of adhesive layer B1 / heat insulation layer C / adhesive layer a1 / heating element b / adhesive layer a2 / heat insulation layer C / adhesive layer B1, and the adhesive layers a1 and a2, and the adhesive layer B1 are made of pressure-sensitive adhesives. Also, for the adhesive tape of Example 1, the size of the adhesive surface (effective part) is width 2 mm × length 50 mm, the size of the nichrome foil is width 2 mm × length 100 mm, and both ends of the nichrome foil extend from the outer periphery of the adhesive layer a1 (and the adhesive layer a2 on the back surface) and are arranged (see FIGS. 8A and B). The volume resistivity of the nichrome foil was 108 μΩ·cm as the catalog value and 105 μΩ·cm as the measured value.

[0174] <Fabrication of the article> Regarding the adhesive tape of Example 1 (indicated by reference numeral 10 in FIGS. 9A to 9C), the release liner closer to the adhesive layer a1 was peeled off, and the tape adhesive surface (effective portion) with a length of 50 mm was applied to the adherend 90a (glass, width 40 mm × length 50 mm × thickness 10 mm) so as to cross the center of the adherend 90a along the length direction of the adherend 90a (see FIGS. 9A to 9C). Next, the release liner on the adhesive layer a2 side was peeled off, and it was pasted in a shape (see FIGS. 9A to 9C) in which the adherend 90b (glass, width 30 mm × length 100 mm × thickness 2.8 mm) sandwiches the adhesive tape 10, and pressure-bonded at 20 N / cm 2 for 10 seconds, and the obtained adhered object was left to stand for 24 hours or more in an atmosphere of 23°C and 50% RH to obtain the article of Example 1.

[0175] (Reference Example 1) In Example 1, except that the laminate (T-2) was not pasted and only the intermediate layer (A-1) was used as the adhesive tape of Reference Example 1, in the same operation as Example 1, a laminate in which the layer configuration excluding the release liner was laminated in the order of adhesive layer a1 / heating element b / adhesive layer a2 was obtained, and an adhesive tape of Reference Example 1 with a total thickness of 110 μm was obtained. Further, in Example 1, except that the adhesive tape of Reference Example 1 was used instead of the adhesive tape of Example 1, in the same operation as Example 1, an article of Reference Example 1 arranged in the order of adherend (glass, width 40 mm × length 50 mm × thickness 10 mm) / adhesive layer a1 / heating element b / adhesive layer a2 / adherend (glass, width 30 mm × length 100 mm × thickness 2.8 mm) was obtained.

[0176] (Example 2) Except that instead of the nichrome foil, a 10-μm-thick stainless steel foil (manufactured by Takeuchi Metal Foil Co., Ltd., product name: "Stainless Steel SUS304-H") with a volume resistivity of 72.0 μΩ·cm as the catalog value and 79.9 μΩ·cm as the measured value was used to obtain the intermediate layer A, in the same operation as Example 1, an adhesive tape and an article of Example 2 with a total thickness of 410 μm were obtained. The intermediate layer A in Example 2 is designated as intermediate layer (A-2).

[0177] (Example 3) Instead of nichrome foil, an intermediate layer A was obtained using a 10-μm-thick stainless steel foil (manufactured by Takeuchi Metal Foil & Powder Industry Co., Ltd., product name: "Stainless Steel SUS430-H") with a volume resistivity of 60.0 μΩ·cm as per the catalog value and 62.0 μΩ·cm as the measured value. An adhesive tape and an article of Example 3 with a total thickness of 410 μm were obtained through the same operations as in Example 1, except for this change. The intermediate layer A in Example 3 is designated as intermediate layer (A-3).

[0178] (Example 4) Instead of nichrome foil, an intermediate layer A was obtained using a 10-μm-thick titanium foil (manufactured by Takeuchi Metal Foil & Powder Industry Co., Ltd., product name: "Titanium Type 1 TR270C-H") with a volume resistivity of 55.0 μΩ·cm as per the catalog value and 51.8 μΩ·cm as the measured value. An adhesive tape and an article of Example 4 with a total thickness of 410 μm were obtained through the same operations as in Example 1, except for this change. The intermediate layer A in Example 4 is designated as intermediate layer (A-4).

[0179] (Example 5) 7.5 g of an amphoteric surfactant (manufactured by Toho Chemical Industry Co., Ltd., product name: "Obazoline CAB-30") and 7.6 g of carbon nanotubes (manufactured by Nanocyl, product name: "NC7000") were mixed in 500 ml of water to form an aqueous solution. Then, the mixture was placed in a ball mill cylinder (volume = 900 ml, ball mill diameter = 130 mm, ball filling amount = 1600 g), gently made into a paste-like substance, and the ball mill cylinder was placed on a rotating stand and stirred for 2 hours. The entire amount of the obtained dispersion-like substance was taken out from the ball mill cylinder, 250 ml of a 15% aqueous solution of the amphoteric surfactant was added, and the mixture was filled into a bead mill (manufactured by WAB, product name: "Dynomill ECM-AP2", internal volume = 1900 ml, filled with 1800 g of zirconia beads with a diameter of 0.6 mm). After that, it was stirred for 60 minutes under the condition of a rotation speed of 300 revolutions per minute to prepare an aqueous dispersion of carbon nanotubes containing an amphoteric surfactant (concentration of carbon nanotubes = 0.99 w%).

[0180] On one side of a polyimide film with a thickness of 25 μm (manufactured by Toray DuPont Co., Ltd., trade name: "Kapton 100H"), the aqueous dispersion of the carbon nanotubes was coated using a bar coater so that the film thickness after drying was 3 μm. The coating film was dried at 100 °C for 10 minutes to form a carbon nanotube layer on one side of the polyimide film, and a carbon nanotube-coated film was obtained. The measured value of the volume resistivity of the carbon nanotube layer was 19270 μΩ·cm.

[0181] Instead of the nichrome foil in Example 1, an adhesive tape and an article of Example 5 with a total thickness of 428 μm were obtained by the same operation as in Example 1, except that the carbon nanotube-coated film was used. The carbon nanotube-coated film was bonded with the carbon nanotube layer adjacent to the adhesive layer a1. The intermediate layer A in Example 5 was designated as intermediate layer (A-5).

[0182] (Example 6) Instead of the nichrome foil, a metal nonwoven fabric (material: SUS316L, thickness 25 μm, density 1.6 g / cm 3 , fiber diameter 7 μm, measured volume resistivity 783 μΩ·cm) was used to obtain an adhesive tape and an article of Example 6 with a total thickness of 425 μm by the same operation as in Example 1, except that the intermediate layer A was obtained. The intermediate layer A in Example 6 was designated as intermediate layer (A-6).

[0183] (Example 7) (Production of Adhesive Tape) A crystalline polyester-based resin coating material (manufactured by Mitsubishi Chemical Corporation, trade name: "Nichigo Polyester MSP-640", melting point 100 °C, molecular weight 10000, tack-free) (P-3) was coated on the release-treated surface of a release liner (a polyethylene terephthalate film with a thickness of 75 μm and one side release-treated) so that the thickness after drying was 50 μm, and dried at 90 °C for 3 minutes to produce a molten softening layer c.

[0184] In the same manner as in Example 1, two adhesive layers with a thickness of 50 μm, which were formed by applying and drying the adhesive composition (P-2) on the release liner, were prepared. One was designated as adhesive layer a1 and the other as adhesive layer a2. Next, a melt-softening layer c cut to a length of 50 mm and an arbitrary width and a nichrome foil with a length of 100 mm were bonded together with a hand roller and positioned so that the nichrome foil extended 25 mm at both ends in the length direction, and then laminated with a roll at 120 °C under a linear pressure of 5 kg / cm. Next, an adhesive layer a1 cut to a length of 50 mm and an arbitrary width was bonded to the surface of the melt-softening layer c from which the release liner had been peeled off. Further, an adhesive layer a2 cut to a length of 50 mm and an arbitrary width was bonded to the opposite surface of the nichrome foil to which the melt-softening layer c and the adhesive layer a1 were bonded, and laminated with a roll at a linear pressure of 5 kg / cm from the upper surface of the release liner, so that both ends of the nichrome foil extended 25 mm each in the length direction of the nichrome foil from the outer peripheries of the melt-softening layer c and the adhesive layers a1 and a2. As a result, a laminate with a total thickness of 160 μm excluding the release liner and having a layer structure of adhesive layer a1 / melt-softening layer c / nichrome foil / adhesive layer a2 laminated in this order was created. After aging this laminate in an environment at 40 °C for 48 hours, it was cut to a width of 2 mm to obtain an intermediate layer (A-7). The intermediate layer (A-7) had a size where the melt-softening layer c and the adhesive layers a1 and a2 were 2 mm × 50 mm in width and length, and the nichrome foil was 2 mm × 100 mm in size, and had a configuration with a pair of extending portions where the nichrome foil extended from the outer peripheries of the melt-softening layer c and the adhesive layers a1 and a2.

[0185] Two laminates (T-2) prepared in Example 1 and cut to a length of 50 mm and an arbitrary width were prepared, and the intermediate layer (A-7) was sandwiched between the two laminates (T-2) so that the foam layers were in contact with both surfaces of the intermediate layer (A-7), and bonded together so that the ends of the melt-softening layer c and the adhesive layers a1 and a2 coincided with the ends of the two laminates (T-2), respectively. The two laminates (T-2) were laminated on the intermediate layer A (A-7) with a roll at a linear pressure of 5 kg / cm from the upper surface of the release liner, respectively, to obtain the adhesive tape of Example 7 with a total thickness of 460 μm.

[0186] The adhesive tape of Example 7 is a laminate in which the layer structure excluding the release liner is laminated in the order of adhesive layer B1 / heat insulation layer C / adhesive layer a1 / melting and softening layer c / heating element b / adhesive layer a2 / heat insulation layer C / adhesive layer B1. The melting and softening layer c is made of a hot melt adhesive, and the adhesive layers a1 and a2, and the adhesive layer B1 are made of pressure-sensitive adhesives. Further, for the adhesive tape of Example 7, the size of the adhesive surface (effective portion) is 2 mm in width × 50 mm in length, and the size of the nichrome foil is 2 mm in width × 100 mm in length. Both ends of the nichrome foil extend from the outer periphery of the melting and softening layer c and the adhesive layers a1 and a2 and are arranged. The volume resistivity of the nichrome foil was 108 μΩ·cm as the catalog value and 105 μΩ·cm as the measured value.

[0187] <Production of Articles> The release liner on the side closer to the melting and softening layer c of the adhesive tape (indicated by reference numeral 10 in FIGS. 9A to 9C) of Example 7 was peeled off, and the tape adhesive surface (effective portion) with a length of 50 mm was applied to the adherend 90a (glass, 40 mm in width × 50 mm in length × 10 mm in thickness) so as to cross the center of the adherend 90a along the length direction of the adherend 90a (see FIGS. 9A to 9C). Next, the release liner on the opposite side of the adhesive tape was peeled off, and it was pasted in a shape (see FIGS. 9A to 9C) in which the adherend 90b (glass, 30 mm in width × 100 mm in length × 2.8 mm in thickness) sandwiches the adhesive tape 10, and it was pressure-bonded at 20 N / cm 2 for 10 seconds. The obtained adhered article was left to stand in an atmosphere of 23°C and 50% RH for 24 hours or more to obtain the article of Example 7.

[0188] (Reference Examples 2 to 7) In Examples 2 to 7, adhesive tapes of Reference Examples 2 to 7 were obtained in the same manner as in Examples 2 to 7, except that the laminate (T-2) was not laminated on both surfaces of the intermediate layer A. The adhesive tapes of Reference Examples 2 to 7 have a structure excluding the release liner consisting only of the intermediate layers (A-2) to (A-7). The total thickness of the adhesive tapes of Reference Examples 2 to 4 was 110 μm, the total thickness of the adhesive tape of Reference Example 5 was 128 μm, the total thickness of the adhesive tape of Reference Example 6 was 125 μm, and the total thickness of the adhesive tape of Reference Example 7 was 160 μm.

[0189] In addition, except that the pressure-sensitive tapes of Reference Examples 2 to 7 were used instead of the pressure-sensitive tapes of Examples 2 to 7, articles of Reference Examples 2 to 7 were obtained by the same operations as those of Examples 2 to 7, respectively.

[0190] <Evaluation> <<Peeling time>> Using the articles of Examples 1 to 7 (excluding Example 5) and Reference Examples 1 to 7 (excluding Reference Example 5) as test pieces, after setting a load L of 500 g / cm 2 in the direction of the arrow shown in FIGS. 9B to 9C, in an environment at 23°C, the extended portion e of the metal foil (heating element) in the pressure-sensitive tape 10 of the test piece was clamped with an alligator clip 60, and a current was passed through the test piece using a dry battery and a resistor (manufactured by uxcell, product name: "Metal Clad Resistor") so that the heat generation amount per second was 37 J. The time (peeling time) until the intermediate layer A peeled off and the adherend 90a dropped and the article was disassembled was measured. In the evaluation of the articles of Example 5 and Reference Example 5, a direct current stabilized power supply (manufactured by Kikusui Electronics Industry Co., Ltd., product name: "PAS160-1") was used instead of the dry battery, and a current was passed through the test piece so that the heat generation amount per second was 5.4 J. The time (peeling time) until the intermediate layer A peeled off and the adherend 90a dropped and the article was disassembled was measured. The results are shown in Table 1. In Examples 1 to 5 and Reference Examples 1 to 5, peeling occurred within the adhesive layer a1 in the intermediate layer A. In Example 6 and Reference Example 6, peeling occurred at the interface between the adhesive layer a1 of the intermediate layer A and the metal nonwoven fabric. In Example 7 and Reference Example 7, peeling occurred within the molten softening layer c of the intermediate layer A.

[0191] <<Heat insulation property: Temperature of adherend>> In the measurement of the peeling time of Examples 1 to 7 (excluding Example 5) and Reference Examples 1 to 7 (excluding Reference Example 5), the temperature of the adherend was measured over time, and the maximum temperature reached by the adherend at the time of disassembly was measured. For the temperature measurement of the adherend, a thin-type temperature sensor (device name: ST-50 (K thermocouple), manufactured by Rika Kogyo Co., Ltd.) and a recorder (device name: midi LOGGER GL200A, manufactured by Graphtec Corporation) were used. The thin-type temperature sensor was set on the surface (opposite side to the tape) of the adherend (glass, width 30 mm × length 100 mm × thickness 2.8 mm). The metal foil at the end of the test piece tape adhesion surface was clamped with an alligator clip, and a current was passed through using a dry battery and a resistor (manufactured by uxcell, product name: "Metal Clad Resistor") so that the heat generation amount per second was 37 J, and the temperature of the adherend at the time of disassembly was measured. In the evaluation of the articles of Example 5 and Reference Example 5, a direct current stabilized power supply (product name: "PAS160-1", manufactured by Kikusui Electronics Industry Co., Ltd.) was used instead of the dry battery, and a current was passed through the test piece so that the heat generation amount per second was 5.4 J, and the temperature of the adherend at the time of disassembly was measured. The results are shown in Table 1.

[0192]

Table 1

Explanation of Symbols

[0193] A Intermediate layer a1, a2, a3 Adhesive layer b Heating element c Melted and softened layer e (Extension part of the heating element) B, B1, B2 Adhesive layer C, C1, C2 Heat insulation layer 10, 20, 30, 40, 50 Adhesive tape 90 Adherend 100 Article 60 Alligator clip L Load

Claims

1. An intermediate layer A containing a heating element and an adhesive, An adhesive layer B1 disposed on one side of the intermediate layer A and containing an adhesive, An adhesive layer B2 disposed on the other side of the intermediate layer A and containing an adhesive, and having, At least one of the adhesive layer B1 and the adhesive layer B2 is a heat insulating layer C having further heat insulating properties, or At least one of the space between the intermediate layer A and the adhesive layer B1 and the space between the intermediate layer A and the adhesive layer B2 further has a heat insulating layer C having heat insulating properties, The heat insulating layer C has a thermal conductivity of 0.15 W / m·K or less, The adhesive tape is characterized in that peeling occurs within the intermediate layer A or between the intermediate layer A and a layer adjacent to the intermediate layer A due to heating of the heating element, making it peelable.

2. An intermediate layer A containing a heating element and an adhesive, An adhesive layer B1 disposed on one side of the intermediate layer A and containing an adhesive, An adhesive layer B2 disposed on the other side of the intermediate layer A and containing an adhesive, and having, At least one of the adhesive layer B1 and the adhesive layer B2 is a heat insulating layer C having further heat insulating properties, or At least one of the space between the intermediate layer A and the adhesive layer B1 and the space between the intermediate layer A and the adhesive layer B2 further has a heat insulating layer C having heat insulating properties, The volume resistivity of the heating element is 30 μΩ·cm or more, The adhesive tape is characterized in that peeling occurs within the intermediate layer A or between the intermediate layer A and a layer adjacent to the intermediate layer A due to resistive heating of the heating element, making it peelable.

3. The adhesive tape according to any one of Claims 1 to 2, having the heat insulating layer C between both the intermediate layer A and the adhesive layer B1 and the intermediate layer A and the adhesive layer B2.

4. The adhesive tape according to any one of Claims 1 to 2, wherein the heat insulating layer C is selected from the group consisting of a foam layer, a hollow-containing layer, and a hollow particle-containing layer.

5. The adhesive tape according to any one of Claims 1 to 2, wherein the thickness of the heat insulating layer C is 15 μm - 1,000 μm.

6. The adhesive tape according to Claim 1, wherein the volume resistivity of the heating element is 30 μΩ·cm or more.

7. The adhesive tape according to Claim 6, wherein the heating element is selected from the group consisting of nichrome, stainless steel, titanium, brass, and carbon.

8. The pressure-sensitive adhesive tape according to any one of claims 1 to 2, wherein the intermediate layer A is a laminate having the planar heating element, and adhesive layers a1 and a2 on each surface of the planar heating element.

9. The pressure-sensitive adhesive tape according to claim 8, wherein in a plan view, the planar heating element has a pair of extending portions extending from the outer peripheries of the adhesive layer a1 and the adhesive layer a2.

10. The pressure-sensitive adhesive tape according to claim 7, wherein at least one of the adhesive layer a1 and the adhesive layer a2 softens or melts upon heating.

11. The pressure-sensitive adhesive tape according to any one of claims 1 to 2, wherein the intermediate layer A consists of a single layer including the heating element and the adhesive.

12. The pressure-sensitive adhesive tape according to any one of claims 1 to 2, wherein the intermediate layer A softens or melts upon heating.

13. The pressure-sensitive adhesive tape according to any one of claims 1 to 2, wherein the temperature at which the loss tangent (tanδ) of the adhesive layer formed by the adhesive becomes 0.45 or more exists in a temperature range of 80°C or more and 200°C or less.

14. At least two adherends, including the pressure-sensitive adhesive tape according to any one of claims 1 to 2 between the two adherends, An article, characterized in that the two adherends are adhered via the pressure-sensitive adhesive tape.

15. The article according to claim 14, wherein in a plan view, the pressure-sensitive adhesive tape has a pair of extending portions extending from the outer periphery of the adherend.

16. A method for disassembling the article according to claim 14, characterized in that the intermediate layer A is softened or melted by heating the heating element to separate the two adherends.

17. The heating of the heating element is resistance heating, The intermediate layer A is electrically connected to a power source, the power source is energized to the heating element, and the intermediate layer A is softened or melted by the resistance heating of the heating element to separate the two adherends. The method for disassembling the article according to claim 16.

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