Thermally conductive easily dismantled adhesive composition, thermally conductive easily dismantled adhesive sheet, bonded body, and bonded body dismantling method

Abstract

The present invention provides a thermally conductive easily dismantled adhesive composition capable of forming a thermally conductive easily dismantled adhesive layer that has superior thermal conductivity, that exhibits a superior adhesive force for firmly adhering an adherend, and that has superior dismantling properties. The present invention relates to: a thermally conductive easily dismantled adhesive composition containing an inorganic expanding agent and a resin, wherein a thermally conductive easily dismantled adhesive layer formed from the thermally conductive easily dismantled adhesive composition is destroyed by stimulation, has a thermal conductivity of 1.0 W / mK or greater, and has a shear adhesive force of 2.5 MPa or greater with respect to an aluminum plate; a thermally conductive easily dismantled adhesive sheet containing the thermally conductive easily dismantled adhesive layer; a bonded body that has superior dismantling properties; and a bonded body dismantling method.

Description

Thermally conductive, easily dismantled adhesive composition, thermally conductive, easily dismantled adhesive sheet, joined body, and method for dismantling joined body

[0001] The present invention relates to a thermally conductive, easily dismantled adhesive sheet, a thermally conductive, easily dismantled adhesive composition, a thermally conductive, easily dismantled adhesive sheet, a bonded body, and a method for dismantling a bonded body.

[0002] Adhesives are used to join components made of various materials, such as resin, rubber, metal, glass, ceramics, and paper, and adhesives are required to perform a variety of functions in addition to joining components. For example, to dissipate heat from heat sources such as ICs and transistors, they must be joined to radiators such as heat sinks, and thermally conductive adhesives are used for this purpose.

[0003] In recent years, research has been conducted into easily dismantlable adhesives that have sufficient adhesive strength for the intended use and the ability to reduce adhesive strength at any time to allow for easy peeling (dismantling). Demand for such easily dismantlable adhesives is growing for applications such as the separate recovery of bonding materials used to bond components made of different materials, the repair and replacement of components, and improving productivity through temporary bonding in manufacturing processes.

[0004] As dismantling means, for example, methods using stimuli such as heating, voltage application, light irradiation, and immersion in chemical solutions are being considered. Dismantling means using heat include, for example, thermal decomposition of resins and additives contained in adhesives, and expansion of additives, and as expansion agents, resin microcapsules containing liquid low-boiling point hydrocarbons and inorganic expansion agents such as expanded graphite are used.

[0005] For example, Patent Document 1 describes a thermally conductive, easily dismantled adhesive sheet having an adhesive layer containing an inorganic expanding agent and a resin, the adhesive layer having an adhesive strength of 1.0 N / 20 mm or more. Patent Document 2 describes an endoscope including an insertion portion in which one or more circuit boards on which electronic circuits are mounted are bonded together with a dismantlable adhesive.

[0006] International Publication No. 2023 / 176800 Japanese Patent Application Laid-Open No. 2013-59438

[0007] However, in conventional techniques, thermal conductivity has not been sufficiently considered, and no adhesive has been obtained that is excellent in thermal conductivity and also has good adhesion and dismantling properties.

[0008] The present invention has been made in view of the above-mentioned circumstances, and aims to provide a thermally conductive, easily dismantled adhesive composition that can form a thermally conductive, easily dismantled adhesive layer that has excellent adhesive strength and thermal conductivity and is also excellent in dismantling properties. The present invention also aims to provide a thermally conductive, easily dismantled adhesive sheet that includes the thermally conductive, easily dismantled adhesive layer, a bonded structure that is excellent in dismantling properties, and a method for dismantling a bonded structure.

[0009] The present inventors have conducted extensive research to solve the above problems, and as a result have found that by controlling the thermal conductivity and shear adhesive strength of a thermally conductive, easily dismantled adhesive layer formed from a thermally conductive, easily dismantled adhesive composition containing an inorganic expanding agent and a resin within specific ranges, a thermally conductive, easily dismantled adhesive composition can be obtained that is capable of forming a thermally conductive, easily dismantled adhesive layer that has excellent thermal conductivity, excellent adhesive strength for firmly bonding adherends, and excellent dismantling properties, and has thus completed the present invention.

[0010] The means for solving the above problems are as follows. [1] A thermally conductive, easily disintegrable adhesive composition comprising an inorganic expanding agent and a resin, wherein a thermally conductive, easily disintegrable adhesive layer formed by the thermally conductive, easily disintegrable adhesive composition breaks down when stimulated, has a thermal conductivity of 1.0 W / mK or more after curing, and has a shear adhesive strength to an aluminum plate of 2.5 MPa or more after curing. [2] The thermally conductive, easily disintegrable adhesive composition according to [1], wherein the inorganic expanding agent is at least one selected from expanded graphite, vermiculite, silicates, vermullandite, aluminum phosphate, tammasit, and hydrosaltite. [3] The thermally conductive, easily disintegrable adhesive composition according to [1], wherein the resin comprises an epoxy resin. [4] The thermally conductive, easily disintegrable adhesive composition according to [1], further comprising a non-expanding inorganic filler, wherein the total content of the inorganic expanding agent and the inorganic filler is 40 to 70 volume % of the thermally conductive, easily disintegrable adhesive composition. [5] The thermally conductive, easily dismantled adhesive composition according to [4], wherein the content of the non-expanding inorganic filler is 2.5 to 20 volume % in the thermally conductive, easily dismantled adhesive composition. [6] The thermally conductive, easily dismantled adhesive composition according to [4], wherein the non-expanding inorganic filler comprises 40 to 100 volume % of a polyhedral filler. [7] A thermally conductive, easily dismantled adhesive layer formed using the thermally conductive, easily dismantled adhesive composition according to any one of [1] to [6]. [8] A thermally conductive, easily dismantled adhesive sheet comprising a thermally conductive, easily dismantled adhesive layer formed using the thermally conductive, easily dismantled adhesive composition according to any one of [1] to [6]. [9] A bonded structure in which two or more adherends are bonded using the thermally conductive, easily dismantled adhesive layer according to [7].

[10] A method for dismantling the bonded structure according to [9], comprising a dismantling step of dismantling the bonded structure by applying a stimulus to the thermally conductive, easily dismantled adhesive layer in the bonded structure.

[0011] The present invention provides a thermally conductive, easily dismantled adhesive composition that exhibits excellent thermal conductivity, excellent adhesive strength for firmly bonding adherends, and is capable of forming a thermally conductive, easily dismantled adhesive layer that is excellent in dismantling properties. Furthermore, a bonded structure bonded with the thermally conductive, easily dismantled adhesive sheet of the present invention that includes the thermally conductive, easily dismantled adhesive layer has excellent dismantling properties, allowing it to be easily dismantled when desired.

[0012] Fig. 1 is a schematic cross-sectional view showing a thermally conductive, easily dismantled adhesive sheet according to an embodiment of the present invention. Fig. 2 is a schematic cross-sectional view showing a thermally conductive, easily dismantled adhesive sheet according to another embodiment of the present invention. Fig. 3 is a schematic cross-sectional view showing a bonded body bonded by a thermally conductive, easily dismantled adhesive layer according to an embodiment of the present invention. Fig. 4 is a schematic cross-sectional view for explaining the evaluation of shear adhesive strength in an example of the present invention. Fig. 5 is a schematic cross-sectional view for explaining the evaluation of dismantling ability in an example of the present invention. Fig. 6 is a diagram showing an SEM image of a cross-section of a thermally conductive, easily dismantled adhesive sheet in an example of the present invention. Fig. 7 is a diagram showing a micrograph of a cross-section of a thermally conductive, easily dismantled adhesive sheet in an example of the present invention.

[0013] The present invention will be described in detail below with reference to the accompanying drawings, but the present invention is not limited to the following embodiments and can be modified as desired without departing from the spirit of the present invention. Furthermore, the term "to" indicating a range of values ​​is used to mean that the values ​​before and after it are included as the lower and upper limits.

[0014] In this specification, "adhesion" means that two surfaces are temporarily joined together by external pressure (microscopic pressure) based on the cohesive force of the chemical structure of the composition, and can be peeled off if necessary.

[0015] "Adhesion" refers to the chemical reaction (curing) of a composition to produce a cured product, which can firmly bond two surfaces. In this specification, "main component" refers to a component contained in an amount of more than 50% by mass, unless otherwise specified. Furthermore, in this specification, percentages based on mass are synonymous with percentages based on weight.

[0016] [Thermal Conductive Easily Disintegrable Adhesive Composition] The thermally conductive, easily disintegrable adhesive composition according to an embodiment of the present invention is a thermally conductive, easily disintegrable adhesive composition comprising an inorganic expander and a resin, wherein a thermally conductive, easily disintegrable adhesive layer formed by the thermally conductive, easily disintegrable adhesive composition is destructible by a stimulus, has a thermal conductivity of 1.0 W / mK or more after curing, and has a shear adhesive strength to an aluminum plate of 2.5 MPa or more after curing.

[0017] That is, the thermally conductive, easily dismantled adhesive composition according to an embodiment of the present invention contains an inorganic expansion agent and a resin, can be formed into a sheet, can be broken by a stimulus, and can form a thermally conductive, easily dismantled adhesive layer having a thermal conductivity of 1.0 W / mK or more and a shear adhesive strength to an aluminum plate of 2.5 MPa or more.

[0018] (Inorganic Expanding Agent) The thermally conductive, easily dismantled adhesive composition according to an embodiment of the present invention contains an inorganic expanding agent. Because the inorganic expanding agent is contained, by applying a stimulus to the thermally conductive, easily dismantled adhesive layer formed by the thermally conductive, easily dismantled adhesive composition, the inorganic expanding agent in the thermally conductive, easily dismantled adhesive layer expands at a desired timing, destroying the thermally conductive, easily dismantled adhesive layer and reducing the adhesive strength, thereby enabling the bonded body to be dismantled.

[0019] The inorganic expanding agent used in the thermally conductive, easily dismantlable adhesive composition according to an embodiment of the present invention is an inorganic filler whose volume expansion rate upon stimulation is 10% or more, preferably 20% or more, more preferably 50% or more, and most preferably 1000% or more. Preferably, the inorganic filler whose volume expansion rate upon heating at 300°C is 10% or more, preferably 20% or more, more preferably 50% or more, and most preferably 1000% or more.

[0020] The type of stimulus is not particularly limited, and examples include heat, electricity, light, chemical reaction, etc., with heat being preferred. When the bonded body is disassembled by a thermal stimulus, heating is preferred. When heating, only the thermally conductive, easily dismantled adhesive layer may be heated, or the entire bonded body may be heated. The heating method is not particularly limited, but examples include heating by a heating oven or electromagnetic induction heating. The heating temperature is preferably 130°C or higher, more preferably 150°C or higher, and even more preferably 180°C or higher. Furthermore, from the viewpoint of disassembling without deforming or altering the adherend, the heating temperature is preferably 400°C or lower, more preferably 370°C or lower, and even more preferably 350°C or lower.

[0021] Examples of inorganic expanding agents include expanded graphite, vermiculite, silicates, vermullandite, aluminum phosphate, tammagite, hydrosaltite, etc., and among these, expanded graphite is preferred. The inorganic expanding agents can be used alone or in combination of two or more.

[0022] Expanded graphite is produced by treating natural graphite, pyrolytic graphite, kish graphite, etc. with sulfuric acid, sodium nitrate, potassium permanganate, bromine, halides, etc. to form an intercalation compound between the graphite layers. By heat treating this at high temperatures, gas is generated from the intercalation compound, which causes the spaces between the graphite layers to expand in the direction perpendicular to the carbon planes.

[0023] The thermally conductive, easily dismantled adhesive layer according to an embodiment of the present invention contains an inorganic expansion agent. Therefore, when heat is applied to a bonded body formed using the thermally conductive, easily dismantled adhesive layer, the inorganic expansion agent expands, easily destroying the thermally conductive, easily dismantled adhesive layer, and the bonded body can be dismantled without damaging the adherend.

[0024] When expanded graphite is used as the inorganic expanding agent, the particle size of the expanded graphite particles before expansion is preferably 1 to 400 μm, more preferably 10 to 200 μm. An average particle size of 1 μm or more provides excellent expansion, while an average particle size of 400 μm or less facilitates dispersion in the thermally conductive, easily dismantled adhesive sheet.

[0025] Furthermore, the thermally conductive, easily dismantled adhesive composition (thermally conductive, easily dismantled adhesive layer) may contain an expansion aid, if necessary.

[0026] The amount of inorganic expanding agent used varies depending on the type, but is preferably 2.5% by volume or more, more preferably 3.5% by volume or more, and even more preferably 5% by volume or more, relative to the resin components contained in the thermally conductive, easily disintegrable adhesive composition, from the viewpoint of facilitating cohesive failure and interfacial failure of the thermally conductive, easily disintegrable adhesive layer. Furthermore, from the viewpoint of dispersibility of the inorganic expanding agent, it is preferably 20% by volume or less, more preferably 18% by volume or less, and even more preferably 15% by volume or less. Furthermore, the content of the inorganic expanding agent in the thermally conductive, easily disintegrable adhesive composition is preferably 2.5 to 20% by volume, more preferably 3.5 to 18% by volume, and even more preferably 5 to 15% by volume.

[0027] (Non-expanding inorganic filler) The thermally conductive, easily disintegrable adhesive composition according to an embodiment of the present invention preferably further contains a non-expanding inorganic filler. The inventors have discovered through their research that by including a non-expanding inorganic filler in the thermally conductive, easily disintegrable adhesive composition in addition to an inorganic expanding agent, bubbles generated by solvent drying during the formation of the thermally conductive, easily disintegrable adhesive layer can be reduced. This is thought to be because the inclusion of a non-expanding inorganic filler in the thermally conductive, easily disintegrable adhesive layer makes it difficult for the inorganic expanding agent to become parallel to the length direction of the thermally conductive, easily disintegrable adhesive layer, making it easier for bubbles to escape.

[0028] In an embodiment of the present invention, the non-expanding inorganic filler is an inorganic filler whose volume expansion rate upon stimulation is less than 10%, preferably 8% or less, more preferably 5% or less. Preferably, the non-expanding inorganic filler is an inorganic filler whose volume expansion rate upon heating at 300°C is less than 10%, preferably 8% or less, more preferably 5% or less.

[0029] In an embodiment of the present invention, the non-expanding inorganic filler is preferably a thermally conductive filler. Examples of thermally conductive fillers include metal oxides such as aluminum oxide, magnesium oxide, beryllium oxide, zinc oxide, silicon oxide, and titanium oxide; metal hydroxides such as aluminum hydroxide; metal nitrides such as aluminum nitride, boron nitride, and silicon nitride; metals such as gold, silver, copper, aluminum, tungsten, titanium, nickel, and iron, and alloys of two or more of these metals; and carbon compounds such as graphite, carbon fiber, fullerenes, graphene, and carbon nanotubes. The thermally conductive filler preferably contains one or more of these, more preferably one or more of metal oxides, metal hydroxides, and metal nitrides, and even more preferably aluminum oxide (alumina).

[0030] The shape of the thermally conductive filler is not particularly limited, and examples thereof include spherical, amorphous, polyhedral, etc. From the viewpoint of obtaining high thermal conductivity, polyhedral shapes are preferred.

[0031] In the embodiment of the present invention, "spherical" refers to a solid having a sphericity of 0.8 or more. The sphericity is measured by taking a photograph with an SEM and calculating the area and perimeter of the observed particle using the formula: (sphericity) = {4π × (area) ÷ (perimeter)} ２}. The closer it is to 1, the closer it is to a perfect circle. A sphere may be a perfect sphere or an approximately spherical shape. In an embodiment of the present invention, a "polyhedron" refers to a solid having multiple flat surfaces. A polyhedron may have at least two flat surfaces, preferably four or more flat surfaces, and more preferably eight or more flat surfaces. There is no particular upper limit to the number of flat surfaces constituting a polyhedron, but a practical upper limit is, for example, about 20. The shape of the flat surfaces is not particularly limited, and examples thereof include polygons (triangles, quadrangles, pentagons, hexagons, etc.). A polyhedron may have curved surfaces in addition to flat surfaces. Examples of polyhedrons include flat, plate-like, columnar, prism-like, cylindrical, and regular polyhedrons. In an embodiment of the present invention, "irregular shape" refers to a shape that does not fall within the definitions of "sphere" and "polyhedron" above.

[0032] In an embodiment of the present invention, the thermally conductive filler preferably includes a polyhedral alumina filler. The thermally conductive filler may include both spherical and polyhedral alumina fillers, or all of the alumina fillers contained in the thermally conductive filler may be polyhedral. The shape of the thermally conductive filler can be confirmed by observation using a scanning electron microscope (SEM), and a filler can be determined to be "polyhedral" if two or more flat surfaces are visible. The use of polyhedral alumina filler (D) can improve thermal conductivity compared to the use of spherical alumina fillers, even with the same filling amount, due to an increased contact area between fillers, making it easier to achieve a thermal conductivity of 1.0 W / mK or more in the thermally conductive, easily dismantled adhesive layer.

[0033] In the thermally conductive, easily dismantled adhesive composition according to an embodiment of the present invention, the particle size of the non-expanding inorganic filler is not particularly limited, but a preferred particle size is an average particle size D50 of 0.1 μm to 100 μm. When expanded graphite is used as the inorganic expanding agent, the average particle size D50 is more preferably 0.1 to 30 μm, and even more preferably 1 to 10 μm. This particle size range optimizes the particle size balance with the expanded graphite, which is a flat, large filler, and slows the settling of the non-expanding inorganic filler over time, making it easier to form a thermally conductive, easily dismantled adhesive layer that has excellent thermal conductivity and is both adhesive and dismantlable.

[0034] In the thermally conductive, easily dismantled adhesive composition according to an embodiment of the present invention, the content of the non-expanding inorganic filler varies depending on the type of filler, but in order to exhibit excellent thermal conductivity relative to the resin component contained in the thermally conductive, easily dismantled adhesive composition, the content is preferably 30% by volume or more, more preferably 40% by volume or more, and even more preferably 50% by volume or more. Furthermore, from the viewpoint of preventing a decrease in adhesive strength, the content is preferably 65% ​​by volume or less, and more preferably 60% by volume or less.

[0035] Furthermore, the thermally conductive, easily disintegrable adhesive composition according to an embodiment of the present invention contains a non-expanding inorganic filler, and the total content of the inorganic expansion agent and the non-expanding inorganic filler in the thermally conductive, easily disintegrable adhesive composition is preferably 40% by volume or more, more preferably 50% by volume or more, and even more preferably 60% by volume or more. Furthermore, from the viewpoint of preventing a decrease in adhesive strength, it is preferably 70% by volume or less. Furthermore, the total content of the inorganic expansion agent and the non-expanding inorganic filler in the thermally conductive, easily disintegrable adhesive composition is preferably 40 to 70% by volume, more preferably 50 to 70% by volume, and even more preferably 60 to 70% by volume. Having the total content of the inorganic expansion agent and the non-expanding inorganic filler be 40% by volume or more has the advantage of achieving high thermal conductivity. Furthermore, if the total content of the inorganic expansion agent and the non-expanding inorganic filler is 70% by volume or less, it is possible to achieve both high thermal conductivity and high shear adhesive strength.

[0036] In the thermally conductive, easily dismantlable adhesive composition according to an embodiment of the present invention, the non-expanding inorganic filler preferably contains 40 to 100% by volume of a polyhedral filler, more preferably 70 to 100% by volume, and even more preferably 100% by volume.

[0037] In the thermally conductive, easily dismantled adhesive composition according to an embodiment of the present invention, by setting the content of polyhedral filler in the non-expanding inorganic filler to 40% by volume or more, the polyhedral fillers or the polyhedral fillers and the flat expanded graphite are more likely to come into surface contact with each other. The use of polyhedral fillers not only enables high thermal conductivity, but also improves the packing properties of expanded graphite, which allows for surface contact with the polyhedral fillers, thereby reducing the minimum amount of resin required for the resin to coat the filler. Therefore, the resin can contribute to adhesion to the interface, making it possible to achieve both the contradictory properties of low shear adhesive strength and high thermal conductivity.

[0038] The expansion starting temperature is preferably 130 to 400°C, more preferably 180 to 350°C, in view of the temperature at which the thermally conductive, easily dismantled adhesive layer is formed from the thermally conductive, easily dismantled adhesive composition, and in view of the relationship between heat resistance durability and dismantling ability when the bonded body is used.

[0039] (Resin) The resin contained in the thermally conductive, easily dismantled adhesive composition (thermally conductive, easily dismantled adhesive layer) according to an embodiment of the present invention is not particularly limited, and may be at least one type of resin, and preferably two or more types of resin.

[0040] The resin according to the embodiment of the present invention preferably includes a first resin having a reactive functional group. Furthermore, the resin according to the embodiment of the present invention preferably includes a second resin that does not have a crosslinked structure or a reactive functional group that reacts with components contained in the thermally conductive, easily disintegrable adhesive layer. Furthermore, the resin according to the embodiment of the present invention preferably includes a third resin having a crosslinked structure. The thermally conductive, easily disintegrable adhesive layer according to the embodiment of the present invention more preferably contains two or more resins with different functional groups, more preferably a first resin, a second resin, and a third resin. Here, "having a crosslinked structure" refers to a resin having crosslinkable groups as functional groups, at least a portion of which has a crosslinked structure, and may or may not contain uncrosslinked crosslinkable groups. Furthermore, "having a reactive functional group" refers to a resin having unreacted functional groups, and the reactive functional group is a functional group that can undergo at least one of polymerization and crosslinking reactions. The first resin may or may not include a crosslinked structure.

[0041] The resin contained in the thermally conductive, easily dismantled adhesive layer corresponds to the resin contained in the thermally conductive, easily dismantled adhesive composition that forms the thermally conductive, easily dismantled adhesive layer, and at least a portion of the functional groups, such as crosslinkable groups, contained in the resin contained in the thermally conductive, easily dismantled adhesive composition that forms the thermally conductive, easily dismantled adhesive layer may be crosslinked.

[0042] Furthermore, examples of functional groups possessed by the resin contained in the thermally conductive, easily dismantlable adhesive composition include functional groups that harden upon heating, etc. Specific examples of such functional groups include, but are not limited to, carboxyl groups, acid anhydride groups, hydroxyl groups, sulfonic acid groups, phosphate groups, amino groups, amide groups, epoxy groups, cyano groups, isocyanate groups, alkoxysilyl groups, ethylenically unsaturated groups (e.g., acryloyl groups, methacryloyl groups, vinyl groups, allyl groups, etc.), benzophenone structures, etc.

[0043] The first resin is preferably a resin containing a reactive functional group selected from a hydroxyl group, an epoxy group, an amide group, and the like.

[0044] The third resin is preferably a resin containing a crosslinked structure in which at least a portion of crosslinkable groups selected from carboxyl groups, hydroxyl groups, amino groups, and the like are crosslinked.

[0045] It is preferable that at least a portion of the functional groups of the third resin in the thermally conductive, easily dismantled adhesive composition be crosslinked, so that the third resin has a crosslinked structure, thereby forming a thermally conductive, easily dismantled adhesive layer.

[0046] Examples of resins according to the present invention include various polymers such as acrylic polymers, rubber polymers, polyester polymers, urethane polymers, epoxy polymers, polyether polymers, silicone polymers, polyamide polymers, fluorine polymers, and thermoplastic resins, as well as silicone compounds and polyol compounds such as polypropylene glycol.

[0047] (First Resin) The first resin according to an embodiment of the present invention is preferably a resin having a reactive functional group. Examples of reactive functional groups include hydroxyl groups, epoxy groups, and amide groups, with epoxy groups being preferred. Examples of the first resin according to an embodiment of the present invention include epoxy resins, phenolic resins, and acrylic resins. The first resin preferably contains an epoxy resin. This allows the thermally conductive, easily dismantled adhesive sheet to be easily and firmly bonded to the adherend. Furthermore, two or more adherends can be easily and firmly bonded via the thermally conductive, easily dismantled adhesive sheet.

[0048] Examples of epoxy resins include bisphenol-based epoxy resins such as bisphenol A-type epoxy resins, bisphenol F-type epoxy resins, bisphenol S-type epoxy resins, and hydrogenated bisphenol A-type epoxy resins; naphthalene-type epoxy resins; biphenyl-type epoxy resins; dicyclo-type epoxy resins; alicyclic-type epoxy resins; triglycidyl isocyanurate epoxy resins; hydantoin epoxy resins; glycidyl ether-type epoxy resins; and glycidylamino-type epoxy resins.

[0049] As the epoxy resin, preferably, bisphenol-based epoxy resins and glycidyl ether-based epoxy resins are used, and more preferably, bisphenol A-type epoxy resins and p-tert-butylphenyl glycidyl ether are used.

[0050] The epoxy resins can be used alone or in combination of two or more kinds.

[0051] The epoxy resin may be in any of a liquid, semi-solid, and solid form at room temperature, but preferably a semi-solid epoxy resin is used alone, or a liquid epoxy resin and a solid epoxy resin are used in combination. This makes it easier to form a tacky, layer-like thermally conductive, easily dismantled adhesive layer from the thermally conductive, easily dismantled adhesive composition.

[0052] Specifically, an epoxy resin that is liquid at room temperature is liquid at 25° C. The viscosity of the liquid epoxy resin at 25° C. is, for example, 30 Pa·s or more, or preferably 80 Pa·s or more, and for example, 500 Pa·s or less, or preferably 300 Pa·s or less.

[0053] Specifically, an epoxy resin that is solid at room temperature is solid at 25° C. The softening point of the solid epoxy resin is, for example, 50° C. or higher, or preferably 55° C. or higher.

[0054] The first resin may be a commercially available product. For example, commercially available epoxy resins include "jER828" (manufactured by Mitsubishi Chemical Corporation), "EX-146" (manufactured by Nagase ChemteX Corporation), and "EPICLON 850" (manufactured by DIC Corporation).

[0055] The blending ratio of the first resin is, for example, 0 parts by mass or more, preferably 5 parts by mass or more, more preferably 10 parts by mass or more, and even more preferably 15 parts by mass or more, per 100 parts by mass of all resin components in the thermally conductive, easily dismantled adhesive composition, and is, for example, 95 parts by mass or less, preferably 90 parts by mass or less, and more preferably 85 parts by mass or less.

[0056] (Second Resin) In the thermally conductive, easily dismantled adhesive composition according to an embodiment of the present invention, the second resin may be a resin of a different type from the first resin, and is preferably selected from resins that do not have a crosslinked structure or a reactive functional group that reacts with a component contained in the adhesive layer.

[0057] Examples of the second resin include natural rubber, butyl rubber, isoprene rubber, chloroprene rubber, thermoplastic acrylic resin, ethylene-vinyl acetate copolymer, ethylene-acrylic acid copolymer, ethylene-acrylic acid ester copolymer, polybutadiene resin, polycarbonate resin, thermoplastic polyimide resin, polyamide resin such as polyamide 6 and polyamide 6,6, phenoxy resin, vinyl butyral resin, acrylic resin, saturated polyester resin such as PET and PBT, polyamide-imide resin, fluororesin, etc. Preferably, the second resin is selected from the group consisting of phenoxy resin, thermoplastic acrylic resin, and polyvinyl butyral resin.

[0058] The second resin may be a commercially available product. For example, commercially available phenoxy resins include "jER1256," "jER1256B40," and "jER4250" (manufactured by Mitsubishi Chemical Corporation), "YP-50S," "YP-50," "YP-70," and "FX-316" (manufactured by Nippon Steel Chemical & Materials Co., Ltd.), thermoplastic acrylic resins include "Nanostrength M-22" and "Nanostrength M-22N" (manufactured by Arkema), and commercially available polyvinyl butyral resins include "Butvar B-79" and "Butvar B-72" (manufactured by Eastman Chemical Co., Ltd.).

[0059] The above resins may be used singly or in combination of two or more. As the thermoplastic resin, phenoxy resin and thermoplastic acrylic resin are preferred, and phenoxy resin is more preferred, from the viewpoint of improving the cohesive strength of the heat-conductive, easily dismantled adhesive layer due to their high heat resistance.

[0060] The blending ratio of the second resin is, for example, 0 parts by mass or more, preferably 1 part by mass or more, more preferably 5 parts by mass or more, and for example, 50 parts by mass or less, preferably 40 parts by mass or less, more preferably 30 parts by mass or less, per 100 parts by mass of all resin components in the thermally conductive, easily dismantled adhesive composition.

[0061] The blending ratio of the second resin, the first resin, and the second resin is, in parts by mass, preferably 0-100:0-100:0-50 (however, at least one of the second resin and the first resin is greater than 0), more preferably 1-90:1-90:1-40, and even more preferably 5-80:5-80:5-30.

[0062] (Third Resin) In the thermally conductive, easily dismantled adhesive layer according to the embodiment of the present invention, the resin preferably further comprises a third resin having a crosslinked structure. In the thermally conductive, easily dismantled adhesive layer according to the embodiment of the present invention, the third resin having a crosslinked structure improves the cohesive strength of the adhesive component, making it easier to achieve a shear adhesive strength of 2.5 MPa or more to the aluminum plate.

[0063] In this embodiment, the type of third resin is not particularly limited, and any known adhesives can be used. For example, the third resin may contain one or more polymers, such as acrylic polymers, rubber polymers, polyester polymers, urethane polymers, polyether polymers, silicone polymers, polyamide polymers, and fluorine-based polymers. From the viewpoints of adhesive performance and cost, it is preferable to use an acrylic polymer, rubber polymer, or urethane polymer as the third resin. Among these, it is more preferable to use an acrylic polymer as the third resin from the viewpoint of adjusting the adhesive strength of the thermally conductive, easily dismantled adhesive layer within a specific range. The following description will mainly focus on thermally conductive, easily dismantled adhesive layers containing an acrylic polymer as the third resin, but it is not intended to limit the thermally conductive, easily dismantled adhesive layer of this embodiment to one composed of an acrylic polymer.

[0064] An "acrylic polymer" refers to a polymer containing, as a monomer unit constituting the polymer, a monomer unit derived from a monomer having at least one (meth)acryloyl group per molecule. Hereinafter, a monomer having at least one (meth)acryloyl group per molecule is also referred to as an "acrylic monomer." Therefore, in this specification, an acrylic polymer is defined as a polymer containing a monomer unit derived from an acrylic monomer. A typical example of an acrylic polymer is an acrylic polymer in which the proportion of acrylic monomers in the total monomer components used in the synthesis of the acrylic polymer is greater than 50% by mass. Furthermore, "(meth)acryloyl" refers collectively to acryloyl and methacryloyl. Similarly, "(meth)acrylate" refers collectively to acrylate and methacrylate, and "(meth)acrylic" refers collectively to acrylic and methacrylic, respectively.

[0065] The (meth)acrylate is an alkyl methacrylate and / or alkyl acrylate, and specific examples thereof include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, isopropyl (meth)acrylate, butyl (meth)acrylate, isobutyl (meth)acrylate, s-butyl (meth)acrylate, t-butyl (meth)acrylate, n-butyl (meth)acrylate, pentyl (meth)acrylate, isopentyl (meth)acrylate, hexyl (meth)acrylate, heptyl (meth)acrylate, octyl (meth)acrylate, and 2-ethylhexyl (meth)acrylate. and alkyl (meth)acrylates having 1 to 20 carbon atoms, such as acrylate, isooctyl (meth)acrylate, nonyl (meth)acrylate, isononyl (meth)acrylate, decyl (meth)acrylate, isodecyl (meth)acrylate, undecyl (meth)acrylate, dodecyl (meth)acrylate, tridecyl (meth)acrylate, tetradecyl (meth)acrylate, pentadecyl (meth)acrylate, hexadecyl (meth)acrylate, heptadecyl (meth)acrylate, octadecyl (meth)acrylate, nonadecyl (meth)acrylate, and eicosyl (meth)acrylate.

[0066] As the (meth)acrylate, preferably, an alkyl (meth)acrylate having 2 to 14 carbon atoms is used, and more preferably, an alkyl (meth)acrylate having 4 to 9 carbon atoms is used.

[0067] The (meth)acrylates can be used alone or in combination of two or more kinds.

[0068] The mixing ratio of the (meth)acrylate relative to the monomer components is, for example, 70 mass % or more, preferably 80 mass % or more, and for example, 99 mass % or less, preferably 98 mass % or less.

[0069] The monomer component may further contain a copolymerizable monomer that is copolymerizable with the (meth)acrylate.

[0070] Examples of the copolymerizable monomer include carboxyl group-containing monomers or acid anhydrides thereof, such as (meth)acrylic acid, itaconic acid, maleic acid, crotonic acid, and maleic anhydride; hydroxyl group-containing (meth)acrylates, such as 2-hydroxyethyl (meth)acrylate and 3-hydroxypropyl (meth)acrylate; amide group-containing monomers, such as (meth)acrylamide, N,N-dimethyl (meth)acrylamide, N-methylol (meth)acrylamide, N-methoxymethyl (meth)acrylamide, and N-butoxymethyl (meth)acrylamide; vinyl esters, such as vinyl acetate; aromatic vinyl compounds, such as styrene and vinyl toluene; (meth)acrylonitrile; N-(meth)acryloylmorpholine; and N-vinyl-2-pyrrolidone.

[0071] As the copolymerizable monomer, preferably, a carboxyl group-containing monomer or a hydroxyl group-containing (meth)acrylate is used, and more preferably, (meth)acrylic acid or 2-hydroxyethyl (meth)acrylate is used.

[0072] These copolymerizable monomers can be used alone or in combination of two or more. Preferably, a carboxyl group-containing monomer and a hydroxyl group-containing (meth)acrylate are used in combination, and more preferably, (meth)acrylic acid and 2-hydroxyethyl (meth)acrylate are used in combination.

[0073] The mixing ratio of the copolymerizable monomer relative to 100 parts by mass of the (meth)acrylate is, for example, 0.1 parts by mass or more, preferably 0.3 parts by mass or more, and for example, 15 parts by mass or less, preferably 10 parts by mass or less.

[0074] To react the monomer components, for example, a (meth)acrylate and, if necessary, a copolymerizable monomer are blended to prepare a monomer component, which is then reacted by a known polymerization method such as solution polymerization, bulk polymerization, emulsion polymerization, or various radical polymerizations.

[0075] The polymerization method is preferably solution polymerization.

[0076] In solution polymerization, for example, a monomer solution is prepared by mixing a monomer component and a polymerization initiator in a solvent, and then the monomer solution is heated.

[0077] Examples of the solvent include organic solvents. Examples of the organic solvent include aromatic solvents such as toluene, benzene, and xylene; ether solvents such as ethyl acetate; ketone solvents such as acetone and methyl ethyl ketone; ester solvents such as ethyl acetate; and amide solvents such as N,N-dimethylformamide. The solvents can be used alone or in combination of two or more, preferably a combination of an aromatic solvent and an ether solvent. The blending ratio of the solvent is, per 100 parts by mass of the monomer component, for example, 10 parts by mass or more, preferably 50 parts by mass or more, and for example, 1,000 parts by mass or less, preferably 500 parts by mass or less.

[0078] Examples of the polymerization initiator include peroxide-based polymerization initiators and azo-based polymerization initiators.

[0079] Examples of the peroxide-based polymerization initiator include organic peroxides such as peroxycarbonate, ketone peroxide, peroxyketal, hydroperoxide, dialkyl peroxide, diacyl peroxide, and peroxyester.

[0080] Examples of the azo polymerization initiator include azo compounds such as 2,2'-azobisisobutyronitrile, 2,2'-azobis(2-methylbutyronitrile), 2,2'-azobis(2,4-dimethylvaleronitrile), and dimethyl 2,2'-azobisisobutyrate.

[0081] As the polymerization initiator, preferably, an azo-based polymerization initiator is used.

[0082] The mixing ratio of the polymerization initiator relative to 100 parts by mass of the monomer components is, for example, 0.01 parts by mass or more, preferably 0.05 parts by mass or more, and for example, 5 parts by mass or less, preferably 3 parts by mass or less.

[0083] The heating temperature is, for example, 50° C. or higher and 80° C. or lower, and the heating time is, for example, 1 hour or higher and 24 hours or lower.

[0084] This polymerizes the monomer components to obtain an acrylic polymer solution containing an acrylic polymer.

[0085] The third resin may be a commercially available product, and examples of commercially available acrylic polymers include "Nanostrength M-22," "Nanostrength M-22N," and "Nanostrength M-65N" (manufactured by Arkema Inc.).

[0086] The blending ratio of the third resin is, for example, 0 parts by mass or more, preferably 1 part by mass or more, more preferably 5 parts by mass or more, and for example, 100 parts by mass or less, preferably 90 parts by mass or less, more preferably 80 parts by mass or less, per 100 parts by mass of all resin components in the thermally conductive, easily dismantled adhesive composition.

[0087] (Crosslinking agent) When a second resin having a crosslinked structure is blended into the thermally conductive, easily dismantled adhesive composition, a crosslinking agent can be blended when preparing the thermally conductive, easily dismantled adhesive composition. This makes it possible to form a thermally conductive, easily dismantled adhesive layer. In addition, the adhesive strength of the thermally conductive, easily dismantled adhesive layer can be easily adjusted to a specific range.

[0088] Examples of the crosslinking agent include an isocyanate-based crosslinking agent, an aziridine-based crosslinking agent, an epoxy-based crosslinking agent, and a metal chelate-based crosslinking agent, and preferably an isocyanate-based crosslinking agent.

[0089] Examples of the isocyanate crosslinking agent include aromatic diisocyanates such as tolylene diisocyanate and xylene diisocyanate, alicyclic diisocyanates such as isophorone diisocyanate, aliphatic diisocyanates such as hexamethylene diisocyanate, and modified products of these isocyanates (specifically, an adduct of trimethylolpropane with tolylene diisocyanate, etc.).

[0090] The crosslinking agent is preferably a modified isocyanate. The mixing ratio of the crosslinking agent is, for example, 1 part by mass or more, preferably 3 parts by mass or more, and, for example, 20 parts by mass or less, preferably 15 parts by mass or less, relative to 100 parts by mass of the second resin. This allows the adhesive strength of the thermally conductive, easily dismantled adhesive layer to be adjusted.

[0091] (Curing Agent) The thermally conductive, easily dismantled adhesive composition may also contain a curing agent. This hardens the thermally conductive, easily dismantled adhesive layer, improving the adhesive strength with the adherend and making it easier to produce a thermally conductive, easily dismantled adhesive sheet with excellent adhesive strength.

[0092] The curing agent is a component that reacts with the resin contained in the thermally conductive, easily dismantled adhesive composition to harden the adhesive. The curing agent may be appropriately selected from curing agents that can harden the resin depending on the type and composition of the resin used.

[0093] Examples of the curing agent include an isocyanate-based crosslinking agent, an aziridine-based crosslinking agent, an epoxy-based crosslinking agent, a silane-based crosslinking agent, a metal chelate-based crosslinking agent, an amine-based curing agent, an amide-based curing agent, a phenol-based curing agent, and an acid anhydride.

[0094] For example, when the resin contains an epoxy resin, the curing agent is preferably an epoxy resin curing agent. The epoxy resin curing agent may be a heat-curing or photo-curing curing agent, and is preferably a heat-curing curing agent.

[0095] The epoxy resin curing agent may be, for example, a nitrogen-containing curing agent that contains nitrogen atoms and reacts with epoxy groups, such as tetramethylguanidine, imidazole or its derivatives, carboxylic acid hydrazides, tertiary amines, aromatic amines, aliphatic amines, dicyandiamide or its derivatives, etc.

[0096] Specific examples of epoxy resin curing agents include dicyandiamide, 3-methyl-1,2,3,6-tetrahydrophthalic anhydride, 4-methyl-1,2,3,6-tetrahydrophthalic anhydride, diethylenetriamine, and triethylenetetramine.

[0097] Commercially available products may be used as the epoxy resin curing agent. Commercially available dicyandiamide products among the epoxy resin curing agents include "EH3636AS" (manufactured by ADEKA Corporation), Dicyandiamide DD (manufactured by Nippon Carbide Industries Co., Ltd.), DICY7, and DICY15 (manufactured by Mitsubishi Chemical Corporation).

[0098] When dicyandiamide is used as the curing agent, the blending ratio is, for example, 1 part by mass or more, preferably 3 parts by mass or more, and, for example, 10 parts by mass or less, relative to 100 parts by mass of all resin components in the thermally conductive, easily dismantled adhesive composition. When the blending ratio of the curing agent is equal to or more than the above lower limit, the thermally conductive, easily dismantled adhesive layer has excellent adhesiveness.

[0099] In the thermally conductive, easily disintegrable adhesive composition according to an embodiment of the present invention, the inorganic non-expansion filler may be surface-treated with a silane coupling agent as a dispersant. The surface treatment here includes not only covalent bonding but also adsorption and hydrogen bonding.

[0100] Examples of the silane coupling agent include epoxy group-containing silane coupling agents such as 3-glycidoxypropyltrimethoxysilane (trade name: KBM-403, manufactured by Shin-Etsu Chemical Co., Ltd.), 3-glycidoxypropyltriethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, and 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane; amino group-containing silane coupling agents such as 3-aminopropyltrimethoxysilane, N-2-(aminoethyl)-3-aminopropylmethyldimethoxysilane, 3-triethoxysilyl-N-(1,3-dimethylbutylidene)propylamine, and N-phenyl-γ-aminopropyltrimethoxysilane; (meth)acrylic group-containing silane coupling agents such as 3-acryloxypropyltrimethoxysilane and 3-methacryloxypropyltriethoxysilane; and isocyanate group-containing silane coupling agents such as 3-isocyanatepropyltriethoxysilane. The silane coupling agent may be used alone or in combination with two or more other silane coupling agents. The silane coupling agent may be pre-mixed with the thermally conductive particles for pretreatment, or may be added when the resin component, inorganic expanding agent, and inorganic non-expanding filler are mixed (integral blend method).

[0101] When a silane coupling agent is used, the blending ratio of the silane coupling agent to the thermally conductive, easily dismantled adhesive composition is, for example, 0.1% by volume or more, preferably 0.2% by volume or more, and, for example, 1% by volume or less. If the blending ratio of the silane coupling agent is equal to or greater than the lower limit, the inorganic non-expansion filler and the resin component become more compatible with each other, which leads to a reduction in microvoids. If the blending ratio is equal to or less than the upper limit, long-term reliability is improved.

[0102] The thermally conductive, easily dismantlable adhesive composition according to an embodiment of the present invention may contain a curing accelerator, if necessary.

[0103] Examples of the curing accelerator that can be used include imidazole compounds, tertiary amine compounds, phosphine compounds, and urea compounds. As imidazole compounds, for example, various grades of the "Curezol" series are commercially available from Shikoku Chemical Industry Co., Ltd., and among these, for example, "Curezol 2MZA-PW" (manufactured by Shikoku Chemical Industry Co., Ltd.), "Curezol 2PHZ-PW" (manufactured by Shikoku Chemical Industry Co., Ltd.), and "Curezol 2MA-OK" (manufactured by Shikoku Chemical Industry Co., Ltd.) can be suitably used. Examples of urea compounds include Omicure U-52 (manufactured by CVC Thermoset Specialties), 3-(3,4-dichlorophenyl)-1,1-dimethylurea (DCMU) (manufactured by Hodogaya Chemical Co., Ltd.), and the like. The curing accelerator can be used alone, or two or more types can be used in combination.

[0104] The blending ratio of the curing accelerator can be appropriately selected depending on the type of curing agent and curing accelerator.

[0105] The thermally conductive, easily dismantled adhesive composition may contain appropriate additives depending on the application of the thermally conductive, easily dismantled adhesive sheet. Examples of such additives include tackifiers (e.g., rosin derivative resins, polyterpene resins, petroleum resins, oil-soluble phenolic resins, etc., which are solid, semi-solid, or liquid at room temperature), leveling agents, crosslinking aids, plasticizers, softeners, antistatic agents, UV absorbers, fillers, antioxidants, antioxidants, light stabilizers, colorants (pigments, dyes, etc.), and foaming agents. Conventional additives can be used in the usual way, and since they do not particularly characterize the present invention, detailed description of these additives is omitted.

[0106] The method for preparing the thermally conductive, easily dismantled adhesive composition is not particularly limited, and for example, a liquid composition containing each component and a solvent can be prepared and obtained using a planetary centrifugal mixer. The thermally conductive, easily dismantled adhesive layer can be formed into a sheet by applying the thermally conductive, easily dismantled adhesive composition to a substrate, drying it, and removing the solvent.

[0107] When a thermally conductive, easily dismantled adhesive layer is formed by applying a thermally conductive, easily dismantled adhesive composition, it can be carried out using a conventional coater such as a gravure roll coater, a reverse roll coater, a kiss roll coater, a dip roll coater, a bar coater, a knife coater, a spray coater, etc. In the thermally conductive, easily dismantled adhesive sheet having a support substrate described later, a method for providing a thermally conductive, easily dismantled adhesive layer on the support substrate may be a direct method in which a thermally conductive, easily dismantled adhesive composition is directly applied to the support substrate to form a thermally conductive, easily dismantled adhesive layer, or a transfer method in which a thermally conductive, easily dismantled adhesive layer formed on a release surface is transferred to the substrate.

[0108] Another method for preparing the thermally conductive, easily dismantled adhesive composition is to heat and knead the components using a kneader such as a twin-screw kneader, a kneader, etc. The thermally conductive, easily dismantled adhesive composition may be compressed and stretched by calendar molding, extrusion molding, press molding, or the like to form a thermally conductive, easily dismantled adhesive layer into a sheet shape.

[0109] (Thermal Conductivity) In an embodiment of the present invention, the thermally conductive, easily dismantled adhesive layer formed from the thermally conductive, easily dismantled adhesive composition has a thermal conductivity of 1.0 W / mK or more after curing.

[0110] In an embodiment of the present invention, by setting the thermal conductivity to 1.0 W / mK or more, excellent thermal conductivity is obtained. For example, when used to bond a heat source and a cooler, the heat dissipation effect from the heat source to the cooler is sufficiently achieved. The thermal conductivity of the thermally conductive, easily dismantled adhesive layer according to an embodiment of the present invention after curing is preferably 1.0 W / mK or more, and more preferably 2.0 W / mK or more. There is no particular upper limit to the thermal conductivity, but it may be 5 W / mK or less because increasing the amount of inorganic non-expansion filler too much reduces the shear adhesive strength.

[0111] The thermal conductivity is measured by the following method for a cured thermally conductive, easily dismantled adhesive layer formed by the following method using the thermally conductive, easily dismantled adhesive composition according to an embodiment of the present invention.

[0112] <Method for forming a thermally conductive, easily dismantled adhesive layer> The thermally conductive, easily dismantled adhesive composition is applied to a release sheet (polyethylene terephthalate film (Mitsubishi Chemical Corporation, Diafoil MRF # 50)) with a bar coater, and then heated (dried) in a heating oven at 100 ° C. for 10 minutes to remove the solvent and form a sheet having a thickness of 100 μm to form a thermally conductive, easily dismantled adhesive layer. Then, the thermally conductive, easily dismantled adhesive layer is contacted with another polyethylene terephthalate film (Mitsubishi Chemical Corporation, Diafoil MHE # 38) so that the thermally conductive, easily dismantled adhesive layer is sandwiched between two polyethylene terephthalate films. Then, lamination is performed using a roll press heated to 80 ° C., and the surface irregularities are smoothed to obtain a smooth, thermally conductive, easily dismantled adhesive sheet (thermally conductive, easily dismantled adhesive layer) with a release liner (polyethylene terephthalate film).

[0113] <Thermal conductivity measurement method> A thermally conductive, easily dismantled adhesive sheet was cut to a size of 20 mm x 20 mm, and 16 100 μm thermally conductive, easily dismantled adhesive layers were laminated to obtain a laminate for thermal conductivity measurement (hereinafter referred to as laminate 1). Both sides of laminate 1 were sandwiched between release sheets (polyethylene terephthalate film (Diafoil MRF #50 manufactured by Mitsubishi Chemical Corporation)), and a 1.7 mm SUS plate was inserted as a spacer. The laminate was pressed at 10 MPa for 20 minutes in a heat press heated to 150 ° C., cured, the release sheet was peeled off, and the thickness of the cured laminate 1 was measured. Shin-Etsu Chemical Co., Ltd.'s heat dissipation silicone oil compound G775 (thickness: 75 μm, thermal conductivity: 3.6 W / mK) was placed on both sides of the cured laminate 1, and the thermal conductivity of the obtained sample was measured using a thermal conductivity measuring device. At this time, the heater is fixed at 110°C and the chiller side is fixed at 20°C, and the measurement is carried out for 10 minutes, and the data when thermal equilibrium is reached is used. From the measured value of the thermal conductivity (W / mK) of the sample + silicone oil compound, the thermal resistance value (Kcm ２ The thermal resistance value (0.556 (Kcm / W) of the silicone oil compound on both sides of the cured product of the laminate 1 was calculated from the thermal resistance value of the sample using equation (2). ２ / W) is subtracted, and the thermal conductivity of the laminate 1 is calculated from the obtained thermal resistance value of the laminate 1 and the thickness of the laminate 1 according to formula (3).

[0114] Equation (1): Thermal resistance value of sample (Kcm ２ / W) = (thickness of laminate 1 (mm) + 0.15 (mm)) ÷ thermal conductivity of sample (W / mK) × 10 Formula (2): Thermal resistance value (Kcm) of laminate 1 ２ / W) = Thermal resistance value of sample (Kcm ２ / W) - 0.556 (Kcm ２ / W) Equation (3): Thermal conductivity of laminate 1 (W / mK) = Thickness of laminate 1 (mm) ÷ Thermal resistance value of laminate 1 (Kcm ２ / W) x 10

[0115] (Shear adhesive strength) In an embodiment of the present invention, the thermally conductive, easily dismantled adhesive layer formed from the thermally conductive, easily dismantled adhesive composition has a shear adhesive strength to an aluminum plate (A5052P) after curing of 2.5 MPa or more. The aluminum plate in the present invention is A5052P. The shear adhesive strength of the thermally conductive, easily dismantled adhesive layer according to an embodiment of the present invention to an aluminum plate (A5052P) after curing is preferably 2.5 MPa or more, more preferably 5 MPa or more.

[0116] The shear adhesive strength is the shear adhesive strength measured at 23 ° C. after curing on an aluminum plate (A5052P) in accordance with JIS K6850 for a thermally conductive, easily dismantled adhesive layer formed by the above method using the thermally conductive, easily dismantled adhesive composition according to an embodiment of the present invention. Specifically, the thermally conductive, easily dismantled adhesive sheet is cut to a size of 25 mm wide x 12.5 mm long to form a measurement sample 50. Then, as shown in FIG. 4, one polyethylene terephthalate film (Diafoil MHE #38 manufactured by Mitsubishi Chemical Corporation) is peeled off, and the tip of an aluminum plate 61 (A5052P) measuring 25 mm wide x 100 mm long x 2 mm thick is placed on one surface 50A of the exposed thermally conductive, easily dismantled adhesive layer. Next, the other polyethylene terephthalate film (Diafoil MRF #50 manufactured by Mitsubishi Chemical Corporation) is peeled off. Next, another aluminum plate 62 (A5052P) is attached to the other surface 50B of the thermally conductive, easily dismantled adhesive layer. Next, the two aluminum plates (A5052P) are fixed with clips and stored in a heating oven at 130°C for 60 minutes to harden the heat-conductive, easily dismantled adhesive layer and obtain a bonded structure. The clips are then removed, and the two aluminum plates (A5052P) are pulled in the shear direction (arrow direction in Figure 4) at a peel rate of 5 mm / min using a tension-compression testing machine (device name AGX-V2, manufactured by Shimadzu Corporation). The test force when one of the two aluminum plates (A5052P) peels off is measured and used as the shear adhesive strength. Shear adhesive strength (MPa) = test force (N) 312.5 / mm ２

[0117] [Thermal Conductive Disintegrable Adhesive Layer] The thermal conductive disintegrable adhesive layer according to an embodiment of the present invention is formed from a thermal conductive disintegrable adhesive composition according to an embodiment of the present invention, which contains an inorganic expanding agent and a resin. The thermal conductive disintegrable adhesive layer has a thermal conductivity of 1.0 W / mK or more and a shear adhesive strength to an aluminum plate of 2.5 MPa or more. The thermal conductivity and shear adhesive strength to an aluminum plate of the thermal conductive disintegrable adhesive layer were measured as described above, and the preferred ranges are also the same.

[0118] The thermally conductive, easily dismantled adhesive layer according to an embodiment of the present invention can be strongly bonded to an adherend by being cured after being applied to the adherend. Two or more adherends can be bonded via a thermally conductive, easily dismantled adhesive sheet (which may also be a thermally conductive, easily dismantled adhesive layer) to form a bonded structure. The thermally conductive, easily dismantled adhesive layer preferably hardens by at least one of a polymerization or crosslinking reaction of the resin contained in the thermally conductive, easily dismantled adhesive layer. In other words, the resin contained in the thermally conductive, easily dismantled adhesive layer preferably has a reactive functional group. Furthermore, the thermally conductive, easily dismantled adhesive layer according to an embodiment of the present invention can preferably be further hardened by at least one of a polymerization or crosslinking reaction after being applied to the adherend.

[0119] The thermally conductive, easily dismantled adhesive layer is preferably formed into a sheet shape from a thermally conductive, easily dismantled adhesive composition.

[0120] The thickness of the thermally conductive, easily dismantled adhesive layer is not particularly limited, and is, for example, 1 μm or more, preferably 10 μm or more, more preferably 50 μm or more, and is, for example, 3000 μm or less, preferably 1000 μm or less, more preferably 500 μm or less, and even more preferably 300 μm or less.

[0121] [Thermal Conductive Dismantling Adhesive Sheet] The thermal conductive dismantling adhesive sheet according to an embodiment of the present invention includes a thermal conductive dismantling adhesive layer formed from a thermal conductive dismantling adhesive composition according to an embodiment of the present invention. The thermal conductive dismantling adhesive layer according to an embodiment of the present invention has a thermal conductivity of 1.0 W / mK or more and a shear adhesive strength to an aluminum plate of 2.5 MPa or more.

[0122] 1 is a schematic cross-sectional view showing a thermally conductive, easily dismantled adhesive sheet according to an embodiment of the present invention. As shown in FIG. 1, the thermally conductive, easily dismantled adhesive sheet 100 according to this embodiment may be composed only of a thermally conductive, easily dismantled adhesive layer 11. While FIG. 1 shows a thermally conductive, easily dismantled adhesive layer having a single layer structure, the thermally conductive, easily dismantled adhesive layer may have a multi-layer structure of two or more layers.

[0123] The thermally conductive, easily dismantled adhesive sheet of this embodiment may include a support substrate as shown in Figure 2. The thermally conductive, easily dismantled adhesive sheet of this embodiment may also include a pressure-sensitive adhesive layer or adhesive layer other than the thermally conductive, easily dismantled adhesive layer 11. There are no particular restrictions on the pressure-sensitive adhesive layer or adhesive layer other than the thermally conductive, easily dismantled adhesive layer 11, and known pressure-sensitive adhesive layers can be used depending on the application of the thermally conductive, easily dismantled adhesive sheet, the material of the adherend, etc.

[0124] 3 is a schematic cross-sectional view showing a bonded structure bonded with a thermally conductive, easily dismantled adhesive sheet according to an embodiment of the present invention. The bonded structure bonded with a thermally conductive, easily dismantled adhesive sheet according to an embodiment of the present invention may be a bonded structure 200 in which a first member 14 and a second member 15 are bonded as adherends via a thermally conductive, easily dismantled adhesive layer 11, as shown in FIG.

[0125] The thermally conductive, easily dismantled adhesive sheet according to an embodiment of the present invention includes the above-described thermally conductive, easily dismantled adhesive layer. The thermally conductive, easily dismantled adhesive sheet according to this embodiment may be a sheet with a supporting substrate in the form of a sheet-like substrate (supporting substrate) having a thermally conductive, easily dismantled adhesive layer on one side (FIG. 2) or both sides thereof, or may be a substrate-less thermally conductive, easily dismantled adhesive sheet in the form of a thermally conductive, easily dismantled adhesive layer held by a release sheet. The concept of the thermally conductive, easily dismantled adhesive sheet referred to here may include those referred to as adhesive tape, adhesive labels, adhesive films, etc.

[0126] The thermally conductive, easily dismantled adhesive layer is typically formed continuously, but is not limited to such a form. For example, the thermally conductive, easily dismantled adhesive layer may be formed in a regular or random pattern such as a dotted or striped pattern. The thermally conductive, easily dismantled adhesive sheet of this embodiment may be in the form of a roll or a sheet. Alternatively, the thermally conductive, easily dismantled adhesive sheet may be processed into various shapes.

[0127] (Supporting substrate) As described above, the thermally conductive, easily dismantled adhesive sheet of this embodiment may also include a supporting substrate as shown in FIG. 2. That is, the thermally conductive, easily dismantled adhesive sheet of this embodiment may further include a supporting substrate, and may be provided with the above-mentioned thermally conductive, easily dismantled adhesive layer on at least one surface of the supporting substrate. This allows the thermally conductive, easily dismantled adhesive sheet to be processed with high precision by punching or the like. Such a thermally conductive, easily dismantled adhesive sheet is also preferred for applications in which it is processed into a specific shape or is used in a narrow width.

[0128] Furthermore, the thickness of the support substrate in this embodiment is preferably 100 μm or less, more preferably 80 μm or less, even more preferably 70 μm or less, even more preferably 50 μm or less, and particularly preferably 30 μm or less. In one aspect, the thickness of the support substrate may be 20 μm or less, 12 μm or less, 7 μm or less, or 3 μm or less. The lower limit of the thickness of the support substrate is not particularly limited. From the viewpoint of the handleability and processability of the thermally conductive, easily dismantled adhesive sheet, the thickness of the support substrate is usually 0.5 μm or more (for example, 1 μm or more). In one aspect, the thickness of the support substrate may be 3 μm or more. In another aspect, the thickness of the support substrate may be 8 μm or more, or may be 13 μm or more, or may be 16 μm or more.

[0129] The structure and material of the support substrate are not particularly limited, and are typically film-like substrates (also referred to as "substrate films"). Substrate films that contain a resin film as a base film are preferably used. The base film is typically a member that can independently maintain its shape (independent). The substrate film in this embodiment may be substantially composed of such a base film. Alternatively, the substrate film may include an auxiliary layer in addition to the base film. Examples of the auxiliary layer include a colored layer, a reflective layer, an undercoat layer, an antistatic layer, etc., provided on the surface of the base film. The substrate film may also be a porous film. The porous film is not particularly limited as long as it has multiple pores within the film (as long as pores are formed), and examples include foam films and nonwoven fabrics. The thermally conductive, easily dismantled adhesive sheet according to an embodiment of the present invention preferably has spaces within the thermally conductive, easily dismantled adhesive sheet in which the inorganic expanding agent expands. Therefore, if the base film is a porous film, the pores (spaces) of the porous film facilitate the expansion of the inorganic expanding agent when the agent expands, and the bonded body can be disassembled more easily.

[0130] The resin film is a film containing a resin material as a main component (for example, a component contained in the resin film at more than 50% by mass). Examples of resin films include polyolefin-based resin films such as polyethylene (PE), polypropylene (PP), and ethylene-propylene copolymer; polyester-based resin films such as polyethylene terephthalate (PET), polybutylene terephthalate (PBT), and polyethylene naphthalate (PEN); polyurethane-based resin films; vinyl chloride-based resin films; vinyl acetate-based resin films; polyimide-based resin films; polyamide-based resin films; fluororesin films; cellophane; and the like. The resin film may also be a rubber-based film such as a natural rubber film or a butyl rubber film. Among these, polyester films are preferred from the viewpoints of handleability and processability, and PET films are particularly preferred.

[0131] [Uses] The thermally conductive, easily dismantled adhesive sheet according to an embodiment of the present invention has high thermal conductivity and is suitable for fixing ICs and transistors, which are heat sources, to heat sinks, heat sinks, etc. In particular, when used in portable electronic devices, for the purpose of improving productivity through separate collection and repair / replacement of components, when used in data servers, it is necessary to remove the heat sink when replacing ICs and other components, and dismantling is therefore required.

[0132] The thermally conductive, easily dismantled adhesive sheet according to an embodiment of the present invention can be used to bond various adherends. The thermally conductive, easily dismantled adhesive layer can be easily destroyed by application of heat or other stimulus, allowing the bonded body to be dismantled without damaging the adherends. Therefore, the thermally conductive, easily dismantled adhesive sheet according to an embodiment of the present invention can be suitably used for bonding adherends made of different materials that need to be separated and recovered, or for temporarily fixing components.

[0133] [Laminate, bonded body, manufacturing method of bonded body, and disassembly method of bonded body] The thermally conductive, easily dismantled adhesive layer and the thermally conductive, easily dismantled adhesive sheet according to the embodiment of the present invention can be used in the manufacturing method of a laminate, a bonded body, and a bonded body. The laminate according to the embodiment of the present invention is a laminate (hereinafter referred to as laminate A) in which two or more adherends are attached using the thermally conductive, easily dismantled adhesive layer according to the embodiment of the present invention. The bonded body according to the embodiment of the present invention is a bonded body in which two or more adherends are joined using the thermally conductive, easily dismantled adhesive layer according to the embodiment of the present invention.

[0134] When two or more adherends are attached or joined using a thermally conductive, easily dismantled adhesive sheet according to an embodiment of the present invention, the thermally conductive, easily dismantled adhesive sheet is preferably a substrate-less sheet consisting only of a thermally conductive, easily dismantled adhesive layer, a sheet having the thermally conductive, easily dismantled adhesive layer on both sides of a supporting substrate, or a sheet having the thermally conductive, easily dismantled adhesive layer on one side of a supporting substrate and another pressure-sensitive adhesive layer or adhesive layer on the other side. That is, in the laminate A and the joined body according to an embodiment of the present invention, a supporting substrate, a pressure-sensitive adhesive layer other than the thermally conductive, easily dismantled adhesive layer, an adhesive layer, etc. other than the thermally conductive, easily dismantled adhesive layer may be present between the adherend and the thermally conductive, easily dismantled adhesive layer.

[0135] The manufacturing method of the bonded body according to the embodiment of the present invention includes a bonding step of bonding the two or more adherends by curing the thermally conductive, easily dismantled adhesive layer in the laminate A according to the embodiment of the present invention. The dismantling method of the bonded body according to the embodiment of the present invention is a method of dismantling the bonded body according to the embodiment of the present invention, and includes a dismantling step of dismantling the bonded body by applying a stimulus to the thermally conductive, easily dismantled adhesive layer in the bonded body.

[0136] The above-mentioned explanations can be directly applied to the thermally conductive, easily dismantled adhesive sheet and adherend in the laminate (laminate A), joined body, joined body manufacturing method, and joined body dismantling method according to the embodiment of the present invention.

[0137] In a bonding method using a thermally conductive, easily dismantled adhesive sheet configured in this manner, for example, a thermally conductive, easily dismantled adhesive layer (which may be a thermally conductive, easily dismantled adhesive sheet) is placed between a first member and a second member, which are adherends, and the first member and the second member are pressed together in a direction that brings them into close contact with each other, thereby bonding the two members together to obtain a laminate A. The thermally conductive, easily dismantled adhesive layer of the laminate A attached using the thermally conductive, easily dismantled adhesive layer is then cured to obtain a bonded body in which the first member and the second member are bonded via the thermally conductive, easily dismantled adhesive layer (which may be a thermally conductive, easily dismantled adhesive sheet). Furthermore, by applying a stimulus such as heat to the thermally conductive, easily dismantled adhesive layer, the inorganic expanding agent in the thermally conductive, easily dismantled adhesive layer expands, destroying the thermally conductive, easily dismantled adhesive layer in the bonded body, allowing the bonded body to be dismantled without damaging the adherends, and separating the first member from the second member.

[0138] When two or more components are joined or separated using a thermally conductive, easily dismantled adhesive layer in this way, it is preferable to satisfy the relationship X≦Y≦Z, where the temperature when forming the thermally conductive, easily dismantled adhesive layer using the thermally conductive, easily dismantled adhesive composition is X° C., the temperature when curing the thermally conductive, easily dismantled adhesive layer is Y° C., and the temperature when destroying the thermally conductive, easily dismantled adhesive layer and dismantling the bonded body is Z° C. This relationship is independent of whether or not heat is used to form, harden, or dismantle the thermally conductive, easily dismantled adhesive layer.

[0139] The materials for the first and second members constituting the adherend and laminate A are not particularly limited, but include, for example, metal materials such as copper, silver, gold, iron, tin, palladium, aluminum, nickel, titanium, chromium, zinc, etc., or alloys containing two or more of these, as well as various resin materials (typically plastic materials) such as polyimide resins, acrylic resins, polyethernitrile resins, polyethersulfone resins, polyester resins (polyethylene terephthalate resins, polyethylene naphthalate resins, etc.), polyvinyl chloride resins, polyphenylene sulfide resins, polyetheretherketone resins, polyamide resins (so-called aramid resins, etc.), polyarylate resins, polycarbonate resins, and liquid crystal polymers, etc., and inorganic materials such as alumina, zirconia, soda glass, quartz glass, and carbon. The adherend may have either a single-layer structure or a multilayer structure, and the surface (attachment surface) to which the thermally conductive, easily dismantled adhesive sheet is attached may be subjected to various surface treatments.

[0140] As described above, the present specification discloses the following: [1] A thermally conductive, easily disintegrable adhesive composition comprising an inorganic expanding agent and a resin, wherein a thermally conductive, easily disintegrable adhesive layer formed by the thermally conductive, easily disintegrable adhesive composition is destructible by a stimulus, has a thermal conductivity of 1.0 W / mK or more after curing, and has a shear adhesive strength to an aluminum plate of 2.5 MPa or more after curing. [2] The thermally conductive, easily disintegrable adhesive composition according to [1], wherein the inorganic expanding agent is at least one selected from expanded graphite, vermiculite, silicates, vermullandite, aluminum phosphate, tammasit, and hydrosaltite. [3] The thermally conductive, easily disintegrable adhesive composition according to [1] or [2], wherein the resin comprises an epoxy resin. [4] The thermally conductive, easily disintegrable adhesive composition according to any one of [1] to [3], further comprising a non-expanding inorganic filler, wherein the total content of the inorganic expanding agent and the inorganic filler in the thermally conductive, easily disintegrable adhesive composition is 40 to 70 volume %. [5] The thermally conductive, easily dismantled adhesive composition according to [4], wherein the content of the non-expanding inorganic filler is 2.5 to 20 volume % in the thermally conductive, easily dismantled adhesive composition. [6] The thermally conductive, easily dismantled adhesive composition according to [4], wherein the non-expanding inorganic filler comprises 40 to 100 volume % of a polyhedral filler. [7] A thermally conductive, easily dismantled adhesive layer formed using the thermally conductive, easily dismantled adhesive composition according to any one of [1] to [6]. [8] A thermally conductive, easily dismantled adhesive sheet comprising a thermally conductive, easily dismantled adhesive layer formed using the thermally conductive, easily dismantled adhesive composition according to any one of [1] to [6]. [9] A bonded structure in which two or more adherends are bonded using the thermally conductive, easily dismantled adhesive layer according to [7].

[10] A method for dismantling the bonded structure according to [9], comprising a dismantling step of dismantling the bonded structure by applying a stimulus to the thermally conductive, easily dismantled adhesive layer in the bonded structure.

[0141] The present invention will be specifically explained below with reference to examples, but the present invention is not limited to these examples in any way.

[0142] [Examples 1 to 13, Comparative Examples 1 to 9] Each component was blended in the blending amounts shown in Tables 1 to 3, dissolved in methyl ethyl ketone (MEK) as a solvent, and kneaded for 10 minutes at 23°C using a planetary centrifugal mixer to prepare a thermally conductive, easily dismantled adhesive composition.

[0143] The thermally conductive, easily dismantled adhesive composition was applied to a release-treated release sheet (polyethylene terephthalate film (Mitsubishi Chemical Corporation, Diafoil MRF #50)) using a bar coater, and then heated (dried) in a heating oven at 100 ° C. for 10 minutes to remove the solvent and form a sheet to a thickness of 100 μm to form a thermally conductive, easily dismantled adhesive layer. Then, the thermally conductive, easily dismantled adhesive layer was contacted with another polyethylene terephthalate film (Mitsubishi Chemical Corporation, Diafoil MHE #38) so that the thermally conductive, easily dismantled adhesive layer was sandwiched between two polyethylene terephthalate films. Then, lamination was performed using a roll press heated to 80 ° C. to smooth out any surface irregularities and obtain a smooth, thermally conductive, easily dismantled adhesive sheet (thermally conductive, easily dismantled adhesive layer) with a release liner (polyethylene terephthalate film).

[0144] <Measurement of Thermal Conductivity> A thermally conductive, easily dismantled adhesive sheet was cut to a size of 20 mm x 20 mm, and 16 100 μm thermally conductive, easily dismantled adhesive layers were laminated to obtain a laminate 1 for measuring thermal conductivity. Both sides of the laminate 1 were sandwiched between release sheets (polyethylene terephthalate film (Diafoil MRF #50 manufactured by Mitsubishi Chemical Corporation)), and with 1.7 mm spacers inserted, the laminate was pressed at 10 MPa for 20 minutes in a heat press heated to 150°C and cured. The release sheets on both sides of the cured product of the obtained laminate 1 were removed, and the thickness was measured using a digital upright gauge R1N-255 manufactured by Ozaki Manufacturing Co., Ltd. Heat-dissipating silicone oil compound G775 (3.6 W / mK) manufactured by Shin-Etsu Chemical Co., Ltd. was placed on both sides of the cured product of the laminate 1, and the thermal conductivity of the sample containing the silicone oil compound was measured using a thermal conductivity measuring device TCM1001 manufactured by Rhesca Corporation. At this time, the heater was fixed at 110°C and the chiller side was fixed at 20°C, and the measurement was carried out for 10 minutes, and the data when thermal equilibrium was reached was used.

[0145] In order to eliminate the influence of the thermal resistance of the silicone oil compound on both sides of the cured product of the laminate 1, the thermal resistance value (Kcm) of the sample + silicone oil compound was calculated from the thermal conductivity (W / mK) of the obtained sample + silicone oil compound. ２ The thermal resistance of the heat-conductive, easily dismantled adhesive sheet was calculated by converting the heat resistance to a thermal conductivity of the laminate 1 into a thermal resistance of 0.075 mm / W, and subtracting the thermal resistance of the silicone oil compound on both sides of the cured product of the laminate 1. The thermal resistance was then recalculated to the thermal conductivity of the laminate 1. The thickness of the oil compound was 0.075 mm, and since it was present on both sides (two layers), it was set to 0.15 mm. The thermal resistance was calculated to be 0.556 Kcm from the thickness and thermal conductivity. ２ / W was calculated.

[0146] Equation (1): Thermal resistance value of sample (Kcm ２ / W) = (thickness of laminate 1 (mm) + 0.15 (mm)) ÷ thermal conductivity of sample (W / mK) × 10 Formula (2): Thermal resistance value (Kcm) of laminate 1 ２ / W) = Thermal resistance value of sample (Kcm ２ / W) - 0.556 (Kcm ２ / W) Equation (3): Thermal conductivity of laminate 1 (W / mK) = Thickness of laminate 1 (mm) ÷ Thermal resistance value of laminate 1 (Kcm ２ / W) x 10

[0147] <Measurement of Shear Adhesion Strength> The shear adhesion strength of the cured thermally conductive, easily dismantled adhesive layer was measured in accordance with JIS K 6850. The thermally conductive, easily dismantled adhesive sheet was cut to a size of 25 mm wide x 12.5 mm long. Then, as shown in FIG. 4, one polyethylene terephthalate film (Diafoil MHE #38 manufactured by Mitsubishi Chemical Corporation) was peeled off, and the tip of an aluminum plate 61A5052P measuring 25 mm wide x 100 mm long x 2 mm thick was placed on one surface 50A of the exposed thermally conductive, easily dismantled adhesive layer. Next, the other polyethylene terephthalate film (Diafoil MRF #50 manufactured by Mitsubishi Chemical Corporation) was peeled off. Next, another aluminum plate A5052P62 was bonded to the other surface 50B of the thermally conductive, easily dismantled adhesive layer. The two aluminum plates A5052P were then secured with clips and stored in a heated oven at 130°C for 60 minutes to cure the thermally conductive, easily dismantled adhesive layer and obtain a bonded sample. The clips were then removed, and the two aluminum plates A5052P were pulled in the shear direction (arrow direction in Figure 4) at a peel rate of 5 mm / min using a tension and compression testing machine (device name "AGX-V2", manufactured by Shimadzu Corporation). The test force when one of the two aluminum plates A5052P peeled off was measured and taken as the shear adhesive strength. Shear adhesive strength (MPa) = test force (N) 312.5 / mm ２

[0148] <Evaluation of Dismantling Properties> Using the same method as for measuring shear adhesive strength, two aluminum plates A5052P were attached using the thermally conductive, easily dismantled adhesive sheets of the Examples and Comparative Examples, and the thermally conductive, easily dismantled adhesive layer was cured to obtain bonded assembly samples. Each assembly sample was then placed on a hot plate preheated to 300°C and heated. The time immediately after placing on the hot plate was set to 0 seconds, and each assembly sample was visually observed. When one aluminum plate A5052P spontaneously peeled off the other aluminum plate A5052P (for example, as shown in Figure 5), it was determined to have spontaneously dismantled. The time was recorded and listed in the table as the 300°C dismantling time (sec).

[0149] Examples and comparative examples are shown in Tables 1 to 3 below.

[0150]

[0151] Each component listed in Tables 1 to 3 is described below.

[0152] Liquid epoxy resin: jER828 (bisphenol A epoxy resin) manufactured by Mitsubishi Chemical Corporation. Phenoxy resin: jER1256B40 (phenoxy resin (solid content 40%, MEK solution)) manufactured by Mitsubishi Chemical Corporation. Monofunctional epoxy resin: EX-146 monofunctional epoxy resin ((p-tert-butylphenyl glycidyl ether)) manufactured by Nagase ChemteX Corporation. Acrylic block polymer: M-65N (solid content 25%, MEK solution) (Mn 108,000 Mw 280,000) manufactured by Arkema Inc.. Curing agent: DICY15 (dicyandiamide) manufactured by Mitsubishi Chemical Corporation. Curing accelerator: DCMU (3-(3,4-dichlorophenyl)-1,1-dimethylurea) manufactured by Hodogaya Chemical Co., Ltd. Silane coupling agent: Shin-Etsu Chemical Co., Ltd. KBM-403 (epoxy-based silane coupling agent (3-glycidoxypropyltrimethoxysilane)) Expanded graphite: NeoGraf Co., Ltd. GG210-200N (average particle size D50 = 90 μm) Polyhedral alumina: Resonaq Co., Ltd. AS-50 (average particle size D50 = 9 μm) Spherical alumina: Resonaq Co., Ltd. CB-P02S (average particle size D50 = 2 μm) Spherical alumina: Resonaq Co., Ltd. CB-P07 (average particle size D50 = 7 μm) Spherical alumina: Resonaq Co., Ltd. CB-A20S (average particle size D50 = 21 μm) Spherical aluminum nitride: Tokuyama Corporation HF-01Dc (average particle size D50 = 1.6 μm) Amorphous aluminum hydroxide: Nippon Light Metal Co., Ltd. B-103 (average particle size D50 = 7 μm)

[0153] Observation of the cross sections of the thermally conductive, easily dismantled adhesive sheets of Examples 1 to 3, 5 and Comparative Example 7 revealed that in Example 2, which contained a thermally conductive filler, the expanded graphite was not parallel to the surface of the thermally conductive, easily dismantled layer but was rather inclined, and the amount of air bubbles present in the thermally conductive, easily dismantled layer was small. SEM images of the cross sections of the thermally conductive, easily dismantled adhesive sheets of Example 2 and Comparative Example 7 and micrographs of the cross sections of the thermally conductive, easily dismantled adhesive sheets of Examples 1 to 3, 5 and Comparative Example 7 are shown in Figures 6 and 7.

[0154] The present invention provides a thermally conductive, easily dismantled adhesive composition that exhibits excellent thermal conductivity, excellent adhesive strength for firmly bonding adherends, and is capable of forming a thermally conductive, easily dismantled adhesive layer that is excellent in dismantling properties. Furthermore, a bonded structure bonded with the thermally conductive, easily dismantled adhesive sheet of the present invention that includes the thermally conductive, easily dismantled adhesive layer has excellent dismantling properties, allowing it to be easily dismantled when desired.

[0155] Although the present invention has been described in detail and with reference to specific embodiments, it will be apparent to those skilled in the art that various changes and modifications can be made without departing from the spirit and scope of the present invention. This application is based on a Japanese patent application (Patent Application No. 2024-109687) filed on July 8, 2024, the contents of which are incorporated herein by reference.

[0156] REFERENCE SIGNS LIST 100 Thermally conductive, easily dismantled adhesive sheet 11 Thermally conductive, easily dismantled adhesive layer 12 Supporting substrate 200 Bonded body 14 First member 15 Second member

Claims

1. A thermally conductive, easily dismantled adhesive composition comprising an inorganic expander and a resin, wherein the thermally conductive, easily dismantled adhesive layer formed by the thermally conductive, easily dismantled adhesive composition is destructible by stimulation, has a thermal conductivity of 1.0 W / mK or more after curing, and has a shear adhesive strength to an aluminum plate of 2.5 MPa or more after curing.

2. The thermally conductive, easily dismantled adhesive composition according to claim 1, wherein the inorganic expanding agent is at least one selected from the group consisting of expanded graphite, vermiculite, silicates, vermullandite, aluminum phosphate, tammasit, and hydrosaltite.

3. The thermally conductive, easily dismantled adhesive composition according to claim 1, wherein the resin comprises an epoxy resin.

4. The thermally conductive, easily dismantled adhesive composition according to claim 1, further comprising a non-expanding inorganic filler, the total content of said inorganic expansion agent and said inorganic filler being 40 to 70 volume % of said thermally conductive, easily dismantled adhesive composition.

5. The thermally conductive, easily dismantled adhesive composition according to claim 1, wherein the content of said inorganic expanding agent in said thermally conductive, easily dismantled adhesive composition is 2.5 to 20% by volume.

6. The thermally conductive, easily dismantlable adhesive composition according to claim 4, wherein the non-expanding inorganic filler contains 40 to 100% by volume of a polyhedral filler.

7. A thermally conductive, easily dismantled adhesive layer formed from the thermally conductive, easily dismantled adhesive composition according to any one of claims 1 to 6.

8. A thermally conductive, easily dismantled adhesive sheet comprising a thermally conductive, easily dismantled adhesive layer formed from the thermally conductive, easily dismantled adhesive composition according to any one of claims 1 to 6.

9. A bonded body in which two or more adherends are bonded using the heat-conductive, easily dismantled adhesive layer according to claim 7.

10. A method for dismantling a bonded body according to claim 9, comprising a dismantling step of dismantling the bonded body by applying a stimulus to the heat-conductive, easily dismantled adhesive layer in the bonded body.

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