Heat dissipation member and heat dissipation device

Abstract

To provide a heat dissipation member and a heat dissipation device equipped with an adhesive layer having excellent thermal conductivity and pump-out resistance.SOLUTION: A heat dissipation member 1 comprises a heat dissipation body 11 and an adhesive layer 12 bonded to the heat dissipation body 11. The thermal conductivity λ of the adhesive layer 12 is between 0.5 W / m K and 10 W / m K. The probe tack value of the surface on the side that is not in contact with the heat dissipation body 11 in the adhesive layer 12 is between 2 mN / 5 mmΦ and 10 mN / 5 mmΦ. The holding power conforming to JIS Z0237:2009 when the adhesive layer 12 is attached to an SUS380 plate is 0 mm as the deviation amount measured under conditions of test temperature 40°C, attachment area 25 mm×25 mm, load 9.8 N, and holding time 40,000 seconds.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a heat dissipating member including a heat sink and an adhesive layer, and a heat dissipating device including the heat dissipating member and the heat generating member. [Background technology]

[0002] Conventionally, heat-dissipating materials having thermal conductivity have been used to dissipate generated heat in electronic devices such as thermoelectric conversion devices, photoelectric conversion devices, and semiconductor devices such as large-scale integrated circuits. For example, methods for efficiently dissipating heat generated from an electronic device to the outside have included providing a heat-dissipating sheet with excellent thermal conductivity or interposing heat-dissipating grease between the electronic device and a heat sink.

[0003] An example of such a heat-dissipating sheet is disclosed in Patent Document 1. The heat-dissipating sheet of Patent Document 1 is produced by applying a coating liquid of a heat-dissipating material containing an adhesive resin, an inorganic filler, a curing agent, and a solvent to a release sheet or a substrate, and then drying it.

[0004] An example of the above-described thermal grease is disclosed in Patent Document 2. The thermal grease in Patent Document 2 uses aluminum, boron nitride, graphite, magnesium oxide, alumina, and aluminum nitride as thermally conductive fillers. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2015-67713 [Patent Document 2] Japanese Patent Application Laid-Open No. 2016-162929 Summary of the Invention [Problem to be solved by the invention]

[0006] However, conventional heat-dissipating sheets do not always provide the desired thermal conductivity. For example, if a heat-dissipating sheet is heavily loaded with inorganic fillers in order to achieve high thermal conductivity, the surface roughness increases, making it difficult for tack to develop, reducing adhesion to the adherend and ultimately reducing thermal conductivity.

[0007] However, conventional thermal greases have the problem of repeatedly expanding and contracting due to the temperature rise and cooling that accompany the operation and shutdown of electronic devices, causing the grease to leak out, a phenomenon known as pump-out. Therefore, it is desirable for the thermal grease placed between the electronic device and the heat sink to be resistant to pump-out and thus less susceptible to leakage.

[0008] The present invention has been made in view of the above circumstances, and has an object to provide a heat dissipation member and a heat dissipation device that include an adhesive layer that has excellent thermal conductivity and pump-out resistance. [Means for solving the problem]

[0009] In order to achieve the above object, first, the present invention provides a heat dissipation component comprising a heat sink and a pressure-sensitive adhesive layer adhered to the heat sink, wherein the thermal conductivity λ of the pressure-sensitive adhesive layer is 0.5 W / m·k or more and 10 W / m·k or less, the probe tack value of the surface of the pressure-sensitive adhesive layer that does not contact the heat sink is 2 mN / 5 mmΦ or more and 10 mN / 5 mmΦ or less, and when the pressure-sensitive adhesive layer is attached to a SUS380 plate, the holding strength in accordance with JIS Z0237:2009 is 0 mm as measured under the following conditions: test temperature 40°C, attachment area 25 mm × 25 mm, load 9.8 N, and holding time 40,000 seconds (Invention 1).

[0010] In the above invention (Invention 1), the pressure-sensitive adhesive layer has the above physical properties, resulting in excellent thermal conductivity and pump-out resistance. In particular, the pressure-sensitive adhesive layer has the above thermal conductivity λ and probe tack value, and the pressure-sensitive adhesive layer has the above probe tack value and holding power, resulting in excellent pump-out resistance.

[0011] In the above invention (Invention 1), the probe tack value of the surface of the pressure-sensitive adhesive layer that comes into contact with the heat sink is preferably 2 mN / 5 mmΦ or more and 10 mN / 5 mmΦ or less (Invention 2).

[0012] In the above inventions (Inventions 1 and 2), the thickness of the pressure-sensitive adhesive layer is preferably 10 μm or more and 50 μm or less (Invention 3).

[0013] In the above inventions (Inventions 1 to 3), the pressure-sensitive adhesive layer preferably contains a pressure-sensitive adhesive resin and graphene having a two-dimensional structure (Invention 4).

[0014] In the above invention (invention 4), it is preferable that the adhesive resin is crosslinked with a crosslinking agent (invention 5).

[0015] In the above inventions (Inventions 4 and 5), it is preferable that the content of the graphene having a two-dimensional structure in the pressure-sensitive adhesive layer is 5 parts by mass or more and 100 parts by mass or less per 100 parts by mass of the pressure-sensitive adhesive resin (Invention 6).

[0016] In the above inventions (Inventions 1 to 6), it is preferable that the heat dissipator is a heat sink having a plurality of heat dissipation plates (Invention 7).

[0017] Secondly, the present invention provides a heat-dissipating device comprising a heat-generating component and the heat-dissipating component (Inventions 1 to 7), characterized in that the heat-dissipating component is adhered to the heat-generating component via the adhesive layer (Invention 8).

[0018] In the above invention (Invention 8), it is preferable that the heat-generating member is an electronic component body, and the heat-dissipating device is a heat-dissipating electronic component (Invention 9). [Effects of the Invention]

[0019] The pressure-sensitive adhesive layer of the heat dissipating member and heat dissipating device according to the present invention has excellent thermal conductivity and pump-out resistance. [Brief explanation of the drawings]

[0020] [Figure 1] 1 is a schematic cross-sectional view of a heat dissipation member according to an embodiment of the present invention. [Figure 2] 1 is a schematic cross-sectional view of a heat dissipation device according to one embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0021] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. [Heat dissipation member] 1, a heat dissipation member 1 according to one embodiment of the present invention includes a heat sink 11 and an adhesive layer 12 adhered to one flat surface (the bottom surface in FIG. 1) of the heat sink 11. In this embodiment, a release sheet 13 for protecting the adhesive layer 12 is laminated on the surface of the adhesive layer 12 that does not come into contact with the heat sink 11, but this is not necessarily required in the present invention.

[0022] The pressure-sensitive adhesive layer 12 in the heat dissipation member 1 according to this embodiment has the following physical properties. First, the thermal conductivity λ of the adhesive layer 12 is 0.5 W / m·k or more and 10 W / m·k or less. Second, the probe tack value of the surface of the adhesive layer 12 that does not contact the heat sink 11 is 2 mN / 5 mmΦ or more and 10 mN / 5 mmΦ or less. Third, the holding strength of the adhesive layer 12 when attached to a SUS380 plate according to JIS Z0237:2009 is 0 mm as the displacement measured under the conditions of a test temperature of 40°C, an attachment area of ​​25 mm × 25 mm, a load of 9.8 N, and a holding time of 40,000 seconds. Specific methods for measuring the thermal conductivity λ, probe tack value, and holding strength are as shown in the test examples described below.

[0023] The pressure-sensitive adhesive layer 12 has the above physical properties, resulting in excellent thermal conductivity and pump-out resistance. In particular, the pressure-sensitive adhesive layer 12 has the above thermal conductivity λ and probe tack value, resulting in excellent thermal conductivity, and the pressure-sensitive adhesive layer 12 has the above probe tack value and holding power, resulting in excellent pump-out resistance. Specifically, the pump-out resistance can suppress the adhesive from seeping out from the pressure-sensitive adhesive layer 12 even when the pressure-sensitive adhesive layer 12 is subjected to repeated heating and cooling cycles in a compressed state.

[0024] The thermal conductivity λ of the pressure-sensitive adhesive layer 12 is 0.5 W / m·k or more, preferably 0.6 W / m·k or more, particularly preferably 1.0 W / m·k or more, and even more preferably 1.5 W / m·k or more. This allows for good thermal conductivity and efficient heat transfer. Furthermore, the thermal conductivity λ of the pressure-sensitive adhesive layer 12 is 10 W / m·k or less, preferably 8 W / m·k or less, particularly preferably 5 W / m·k or less. This makes it easier to obtain the desired probe tack value and holding power, achieving an excellent balance between them and effectively improving pump-out resistance.

[0025] The probe tack value of the surface of the adhesive layer 12 that does not contact the heat sink 11 is 2 mN / 5 mmΦ or more, preferably 2.5 mN / 5 mmΦ or more, particularly preferably 3.0 mN / 5 mmΦ or more, and even more preferably 4.0 mN / 5 mmΦ or more. This allows for good adhesion to the adherend, and in particular good adhesion to the member to which the heat sink 1 is adhered (for example, the heat-generating member described below). As a result, adhesion to the adherend is improved, enabling more efficient heat transfer.

[0026] The probe tack value of the pressure-sensitive adhesive layer 12 is preferably 10 mN / 5 mmΦ or less, and particularly preferably 9 mN / 5 mmΦ or less, which makes it easier to obtain the desired thermal conductivity λ and coercive force, resulting in an excellent balance between the two and effectively improving pump-out resistance.

[0027] The probe tack value of the surface of the adhesive layer 12 that contacts the heat sink 11 is preferably 2 mN / 5 mmΦ or more, more preferably 2.5 mN / 5 mmΦ or more, particularly preferably 3 mN / 5 mmΦ or more, and even more preferably 4 mN / 5 mmΦ or more. This allows the adhesive layer 12 to exhibit good adhesiveness to the heat sink 11. As a result, heat can be transferred more efficiently from a heat-generating component or the like to the heat sink 11.

[0028] The probe tack value of the pressure-sensitive adhesive layer 12 is preferably 10 mN / 5 mmΦ or less, and particularly preferably 9 mN / 5 mmΦ or less, which makes it easier to obtain the desired thermal conductivity λ and coercive force, resulting in an excellent balance between them and effectively improving pump-out resistance.

[0029] The holding power of the pressure-sensitive adhesive layer 12 is 0 mm as a displacement measured under the conditions of a measurement test temperature of 40°C, an application area of ​​25 mm x 25 mm, a load of 9.8 N, and a holding time of 40,000 seconds. Such high holding power of the pressure-sensitive adhesive layer 12 results in excellent pump-out resistance, as described above. In particular, even when the pressure-sensitive adhesive layer 12 thermally expands and contracts in a compressed state, bleeding of the pressure-sensitive adhesive from the pressure-sensitive adhesive layer 12 is suppressed. The holding power of the pressure-sensitive adhesive layer 12 is preferably 0 mm as a displacement at a holding time of 45,000 seconds, more preferably 0 mm as a displacement at a holding time of 50,000 seconds, particularly preferably 0 mm as a displacement at a holding time of 60,000 seconds, and even more preferably 0 mm as a displacement at a holding time of 70,000 seconds.

[0030] The thickness of the pressure-sensitive adhesive layer 12 is preferably 10 μm or more, particularly preferably 15 μm or more, and even more preferably 20 μm or more. This makes it easier to obtain the above-mentioned probe tack value, holding power, and thermal conductivity λ. The thickness of the pressure-sensitive adhesive layer 12 is also preferably 50 μm or less, particularly preferably 45 μm or less, and even more preferably 40 μm or less. This makes it easier to obtain the above-mentioned holding power and thermal conductivity λ. In other words, when the thickness of the pressure-sensitive adhesive layer 12 is within the above range, the thermal conductivity and pump-out resistance are improved.

[0031] When the surface area of ​​the surface of heat sink 11 to which adhesive layer 12 is adhered (the bottom surface in FIG. 1 ) is S0 and the contact area between heat sink 11 and adhesive layer 12 is S, the ratio of S to S0 (S / S0) is preferably 1.0 or less, more preferably 0.99 or less, and particularly preferably 0.9 or less. This effectively prevents the adhesive from seeping out beyond heat sink 11 and contaminating the surrounding area, resulting in better pump-out resistance. Furthermore, the ratio of S to S0 (S / S0) is preferably 0.6 or more, more preferably 0.8 or more, and particularly preferably 0.9 or more. This allows for more efficient heat transfer via adhesive layer 12.

[0032] 1. Each component 1-1.Heat dissipator The heat sink 11 in this embodiment is a member that dissipates received heat. The heat sink 11 is preferably made of a material with high thermal conductivity, such as a metal such as aluminum, stainless steel, or copper, or graphite or carbon nanofiber. The form of the heat sink 11 is typically, but is not limited to, a heat sink.

[0033] The heat sink is preferably one having a plurality of heat sink plates, and particularly preferably one having a plurality of heat sink plates arranged parallel to one another on a base, or a plurality of heat sink plates arranged in parallel or in a column in a vertical and horizontal direction in a plan view. The surface of the heat sink that contacts the pressure-sensitive adhesive layer 12 is preferably flat.

[0034] 1-2. Adhesive layer The adhesive layer 12 in this embodiment (the adhesive constituting the adhesive layer 12) preferably contains an adhesive resin and graphene having a two-dimensional structure and / or a thermally conductive filler (excluding graphene having a two-dimensional structure), and more preferably contains an adhesive resin and graphene having a two-dimensional structure. This makes it easier to satisfy the above-mentioned physical properties, particularly the thermal conductivity λ and the probe tack value. Furthermore, the adhesive resin is preferably crosslinked with a crosslinking agent. This makes it easier to satisfy the above-mentioned holding power.

[0035] (1) Each ingredient (1-1) Adhesive resin The type of adhesive resin in this embodiment is not particularly limited, and may be, for example, any of acrylic, polyester, polyurethane, rubber, silicone, etc. Furthermore, the adhesive may be any of emulsion type, solvent type, or solventless type, and may be any of crosslinked type or non-crosslinked type. Furthermore, it may be either non-curable with active energy rays or curable with active energy rays. Among the above, acrylic adhesive resins are preferred, as they are more likely to satisfy the aforementioned probe tack value and holding power.

[0036] Preferred examples of acrylic adhesive resins include (meth)acrylic acid ester polymers obtained by polymerizing (meth)acrylic acid ester monomers. In this specification, (meth)acrylic acid refers to both acrylic acid and methacrylic acid. The same applies to other similar terms. Furthermore, the term "polymer" also includes the concept of "copolymer."

[0037] The (meth)acrylic acid ester polymer as the adhesive resin preferably contains a (meth)acrylic acid alkyl ester as a monomer unit constituting the polymer. This allows the resulting adhesive to exhibit good adhesiveness. The alkyl group may be linear, branched, or cyclic.

[0038] From the viewpoint of adhesiveness, the (meth)acrylic acid alkyl ester is preferably a (meth)acrylic acid alkyl ester in which the alkyl group has 1 to 20 carbon atoms. Examples of the (meth)acrylic acid alkyl ester in which the alkyl group has 1 to 20 carbon atoms include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, n-butyl (meth)acrylate, n-pentyl (meth)acrylate, n-hexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, isooctyl (meth)acrylate, n-decyl (meth)acrylate, n-dodecyl (meth)acrylate, myristyl (meth)acrylate, palmityl (meth)acrylate, and stearyl (meth)acrylate.

[0039] Among the above, from the viewpoint of easily achieving the aforementioned probe tack value and retention, (meth)acrylic acid esters having an alkyl group with 1 to 14 carbon atoms are preferred, (meth)acrylic acid esters having an alkyl group with 2 to 10 carbon atoms are more preferred, and (meth)acrylic acid esters having an alkyl group with 4 to 8 carbon atoms are particularly preferred. Specifically, for example, methyl acrylate, ethyl (meth)acrylate, n-butyl (meth)acrylate, or 2-ethylhexyl (meth)acrylate is preferred, and n-butyl acrylate or 2-ethylhexyl acrylate is particularly preferred. These may be used alone or in combination of two or more.

[0040] From the viewpoint of easily achieving the above-mentioned probe tack value and holding power, the (meth)acrylic acid ester polymer preferably contains 20% by mass or more, more preferably 30% by mass or more, particularly preferably 35% by mass or more, and even more preferably 40% by mass or more of (meth)acrylic acid alkyl ester as a monomer unit constituting the polymer. Furthermore, from the viewpoint of ensuring the content of other monomers (for example, reactive functional group-containing monomers described below), the (meth)acrylic acid alkyl ester is preferably contained in an amount of 99% by mass or less, more preferably 97% by mass or less, particularly preferably 95% by mass or less, and even more preferably 93% by mass or less.

[0041] The (meth)acrylic acid ester polymer as the adhesive resin preferably contains, as a monomer constituting the polymer, a reactive functional group-containing monomer having a reactive functional group in the molecule. This allows the reactive functional group derived from the reactive functional group-containing monomer to become a crosslinking point upon reaction with a crosslinking agent, which will be described later, to form a crosslinked structure. As a result, the aforementioned holding power is more easily achieved. Furthermore, the inclusion of the reactive functional group-containing monomer can improve the dispersibility of graphene having a two-dimensional structure due to its polarity, etc.

[0042] Preferred examples of the reactive functional group-containing monomer include a monomer having a hydroxyl group in the molecule (hydroxyl group-containing monomer), a monomer having a carboxyl group in the molecule (carboxyl group-containing monomer), and a monomer having an amino group in the molecule (amino group-containing monomer). Among these, a hydroxyl group-containing monomer or a carboxyl group-containing monomer is preferred. These reactive functional group-containing monomers may be used alone or in combination of two or more.

[0043] Examples of hydroxyl group-containing monomers include (meth)acrylic acid hydroxyalkyl esters such as 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 3-hydroxybutyl (meth)acrylate, and 4-hydroxybutyl (meth)acrylate. Among these, from the viewpoints of reactivity with a crosslinking agent and dispersibility of graphene having a two-dimensional structure, 2-hydroxyethyl (meth)acrylate is preferred, and 2-hydroxyethyl acrylate is particularly preferred. These may be used alone or in combination of two or more.

[0044] Examples of carboxyl group-containing monomers include ethylenically unsaturated carboxylic acids such as acrylic acid, methacrylic acid, crotonic acid, maleic acid, itaconic acid, and citraconic acid. Among them, acrylic acid is preferred from the viewpoints of reactivity with a crosslinking agent and dispersibility of graphene having a two-dimensional structure. These may be used alone or in combination of two or more.

[0045] The (meth)acrylic acid ester polymer preferably contains, as a monomer constituting the polymer, a reactive functional group-containing monomer in an amount of at least 0.1 mass%, more preferably at least 0.5 mass%, particularly preferably at least 1 mass%, and even more preferably at least 5 mass%. The (meth)acrylic acid ester polymer (A) preferably contains, as a monomer unit constituting the polymer, a reactive functional group-containing monomer in an amount of at most 60 mass%, more preferably at most 55 mass%, particularly preferably at most 50 mass%, and even more preferably at most 45 mass%.

[0046] When the reactive functional group-containing monomer is a hydroxyl group-containing monomer, the content is preferably 0.1 to 60% by mass, more preferably 1 to 50% by mass, particularly preferably 5 to 40% by mass, and even more preferably 10 to 30% by mass. When the reactive functional group-containing monomer is a carboxyl group-containing monomer, the content is preferably 0.1 to 60% by mass, more preferably 0.5 to 50% by mass, particularly preferably 1 to 40% by mass, and even more preferably 5 to 15% by mass. By keeping the amount of the reactive functional group-containing monomer within the above range, the aforementioned holding power is more easily achieved.

[0047] The (meth)acrylic acid ester polymer as the adhesive resin may further contain other monomers as the monomers constituting the polymer. Examples of such other monomers include (meth)acrylic acid alkoxyalkyl esters such as methoxyethyl (meth)acrylate and ethoxyethyl (meth)acrylate; non-crosslinkable acrylamides such as acrylamide and methacrylamide; non-crosslinkable (meth)acrylic acid esters having a tertiary amino group such as N,N-dimethylaminoethyl (meth)acrylate and N,N-dimethylaminopropyl (meth)acrylate; vinyl acetate; styrene, etc. These may be used alone or in combination of two or more.

[0048] The polymerization mode of the (meth)acrylic acid ester polymer may be a random polymer or a block polymer.

[0049] The weight-average molecular weight of the (meth)acrylic acid ester polymer is preferably 10,000 or more, more preferably 20,000 or more, particularly preferably 50,000 or more, and even more preferably 100,000 or more. The weight-average molecular weight is preferably 2,000,000 or less, more preferably 1,500,000 or less, particularly preferably 1,200,000 or less, and even more preferably 1,000,000 or less. Having a weight-average molecular weight within the above range makes it easier to achieve the aforementioned probe tack value and retention. The weight-average molecular weight in this specification is a value measured by gel permeation chromatography (GPC) in terms of standard polystyrene.

[0050] The pressure-sensitive adhesive in this embodiment may contain one or more of the above-mentioned (meth)acrylic acid ester polymers. Furthermore, the pressure-sensitive adhesive in this embodiment may contain another (meth)acrylic acid ester polymer in addition to the above-mentioned (meth)acrylic acid ester polymer.

[0051] The content of the adhesive resin in the adhesive is preferably 30% by mass or more, more preferably 35% by mass or more, particularly preferably 40% by mass or more, and even more preferably 50% by mass or more, based on the total amount of solids (i.e., when the total solids excluding the solvent are taken as 100% by mass). Furthermore, the content is preferably 90% by mass or less, more preferably 85% by mass or less, and particularly preferably 80% by mass or less. By keeping the adhesive resin content within the above ranges, the aforementioned thermal conductivity λ, probe tack value, and holding power are more likely to be satisfied.

[0052] (1-2) Graphene with a two-dimensional structure Graphene is a two-dimensional compound originally consisting of one layer of atoms, with a two-dimensional structure in which carbon atoms are regularly arranged in a hexagonal shape. In this specification, "graphene having a two-dimensional structure" may be multi-layered, and preferably has a thickness of 1 / 10 or less of the shortest length in a planar view. Note that, in this specification, graphene also includes graphene produced by thinly exfoliating (cleaving) graphite.

[0053] The two-dimensional graphene of this embodiment has a planar structure that extends two-dimensionally, which facilitates contact between graphene particles and facilitates the formation of a thermal conduction path for heat transfer within the adhesive. Furthermore, the two-dimensional graphene has a very high thermal conductivity of approximately 3000 W / m·K in the planar direction. Furthermore, graphene has a specific gravity of approximately 2.25, which is lower than conventional inorganic fillers such as metals, metal oxides, and nitride compounds, making it less susceptible to settling. Therefore, even if a relatively small amount of two-dimensional graphene is used, the adhesive layer 12 exhibits excellent thermal conductivity. In other words, in this embodiment, the use of two-dimensional graphene more easily satisfies the aforementioned thermal conductivity λ, probe tack value, and holding power.

[0054] As described above, graphene having a two-dimensional structure may be a single layer or a multi-layer. In the case of a multi-layer, the number of layers is usually about 2 to 1,000. The shape of the graphene having a two-dimensional structure in a plan view is not particularly limited.

[0055] The graphene having a two-dimensional structure of this embodiment is preferably graphene having a two-dimensional crystal structure because it has better thermal conductivity. Here, "graphene having a two-dimensional crystal structure" refers to graphene that has structural periodicity in two dimensions and has layers each having a thickness of a single atom, and that is composed of only the layer or that has two to several hundred layers stacked by van der Waals forces. Experimentally, in wide-angle X-ray diffraction (WAXD) measurements of such "graphene having a two-dimensional crystal structure," clear crystal peaks are obtained from the periodic structure. Furthermore, in the case of graphene having multiple layers, crystal peaks attributable to the periodic structure in the thickness direction of the stack are also obtained.

[0056] When an adhesive layer containing graphene having a two-dimensional crystal structure is measured by X-ray diffraction using a CuKα radiation source (wavelength 0.15418 nm), peaks are preferably detected at 2θ positions of 26.6° and 42.4°. The diffraction peaks at 2θ positions of 26.6° and 42.4° are interlayer and intraplane crystalline peaks of graphene, and the detection of peaks at such positions indicates that the graphene has a crystalline structure.

[0057] The method for producing graphene having a two-dimensional structure is not particularly limited, but examples thereof include a method of physically cleaving graphite, a method of cleaving once oxidized graphite to form a single layer (graphene oxide) and then reducing this to produce graphene oxide (reduced graphene oxide (RGO)), etc. Among these, graphene obtained by a method of physically cleaving graphite is preferred because it has a good two-dimensional crystal structure and therefore has better thermal conductivity.

[0058] The average particle size of the graphene having a two-dimensional structure is preferably 0.5 μm or more, more preferably 1.0 μm or more, particularly preferably 3.0 μm or more, and even more preferably 5.0 μm or more. This facilitates contact between the graphene particles and facilitates the formation of heat conduction paths, thereby utilizing the characteristics of the two-dimensional structure and increasing the thermal conductivity λ of the pressure-sensitive adhesive layer 12. Furthermore, the average particle size of the graphene having a two-dimensional structure is preferably 30 μm or less, particularly preferably 20 μm or less, and even more preferably 15 μm or less. This maintains the dispersed state in other materials such as solvents and adhesive resins, suppresses the failure of heat conduction paths due to segregation, and increases the thermal conductivity λ of the pressure-sensitive adhesive layer 12.

[0059] The thickness of the graphene having a two-dimensional structure is preferably 500 nm or less, more preferably 300 nm or less, particularly preferably 200 nm or less, and even more preferably 100 nm or less. This makes it easier to achieve the aforementioned probe tack value and holding power. On the other hand, the lower limit of the thickness of the graphene having a two-dimensional structure is not particularly limited, but is usually 0.7 nm or more. From the viewpoint of the thermal conductivity λ of the pressure-sensitive adhesive layer 12, it is preferably 5.0 nm or more, particularly preferably 10 nm or more, and even more preferably 15 nm or more.

[0060] The content of the graphene having a two-dimensional structure is preferably 5 parts by mass or more, more preferably 10 parts by mass or more, relative to 100 parts by mass of the adhesive resin. The content of the graphene having a two-dimensional structure is preferably 100 parts by mass or less, more preferably 50 parts by mass or less, relative to 100 parts by mass of the adhesive resin. By having the content of the graphene having a two-dimensional structure within the above range, the thermal conductivity λ, probe tack value, and holding power described above are more likely to be satisfied.

[0061] (1-3) Thermally conductive filler Examples of the thermally conductive filler include fillers made of alumina, silica, carbon black, graphite, aluminum nitride, boron nitride, magnesium carbonate, magnesium oxide, zinc oxide, etc. These thermally conductive fillers may be used alone or in combination.

[0062] When the pressure-sensitive adhesive in the present embodiment contains a thermally conductive filler (excluding graphene having a two-dimensional structure), the content thereof is preferably 5 to 800 parts by mass, more preferably 10 to 500 parts by mass, and particularly preferably 20 to 100 parts by mass, relative to 100 parts by mass of the (meth)acrylic acid ester polymer.

[0063] (1-4) Crosslinking agent The crosslinking agent crosslinks the (meth)acrylic acid ester polymer to form a good three-dimensional network crosslinked structure, which makes it easier to achieve the aforementioned holding power.

[0064] The crosslinking agent may be any agent that reacts with the reactive functional group (hydroxyl group or carboxy group) possessed by the (meth)acrylic acid ester polymer, and examples thereof include isocyanate-based crosslinking agents, epoxy-based crosslinking agents, amine-based crosslinking agents, melamine-based crosslinking agents, aziridine-based crosslinking agents, hydrazine-based crosslinking agents, aldehyde-based crosslinking agents, oxazoline-based crosslinking agents, metal alkoxide-based crosslinking agents, metal chelate-based crosslinking agents, metal salt-based crosslinking agents, ammonium salt-based crosslinking agents, etc. The crosslinking agents may be used alone or in combination of two or more.

[0065] The isocyanate-based crosslinking agent contains at least a polyisocyanate compound. Examples of polyisocyanate compounds include aromatic polyisocyanates such as tolylene diisocyanate, diphenylmethane diisocyanate, and xylylene diisocyanate; aliphatic polyisocyanates such as hexamethylene diisocyanate; alicyclic polyisocyanates such as isophorone diisocyanate and hydrogenated diphenylmethane diisocyanate; and biuret and isocyanurate forms thereof, as well as adducts thereof that are reaction products with low-molecular-weight active hydrogen-containing compounds such as ethylene glycol, propylene glycol, neopentyl glycol, trimethylolpropane, and castor oil. Among these, tolylene diisocyanate, hexamethylene diisocyanate, and modified forms thereof (e.g., trimethylolpropane modified forms) are preferred from the viewpoint of reactivity with reactive functional groups.

[0066] The content of the crosslinking agent in the pressure-sensitive adhesive is preferably 0.01 to 20 parts by mass, more preferably 0.1 to 15 parts by mass, and particularly preferably 1 to 10 parts by mass, per 100 parts by mass of the (meth)acrylic acid ester polymer, which makes it easier to achieve the aforementioned holding power.

[0067] (1-5) Various additives If desired, the adhesive of the present embodiment may contain additives such as an antistatic agent, a tackifier, an antioxidant, a softener, a filler, a rust inhibitor, and a flame retardant. Note that the solvent described below is not included in the additives constituting the adhesive.

[0068] (2) Preparation of adhesive coating solution The pressure-sensitive adhesive coating solution of this embodiment can be prepared by a conventional method, but when graphene having a two-dimensional structure is used, the method for preparing the pressure-sensitive adhesive coating solution of this embodiment preferably includes a first step of dispersing a mixture containing a part of the total amount of the pressure-sensitive adhesive resin to be blended, graphene having a two-dimensional structure, and a solvent to obtain a pre-mixture, and a second step of adding the remainder of the pressure-sensitive adhesive resin and the solvent to the pre-mixture and dispersing the mixture, thereby obtaining a pressure-sensitive adhesive coating solution in which graphene having a two-dimensional structure is uniformly dispersed.

[0069] When the pressure-sensitive adhesive of the present embodiment contains a crosslinking agent, the crosslinking agent is preferably added in the second step described above.

[0070] (2-1) First step In the first step of this embodiment, a mixture containing a portion of the total amount of adhesive resin to be blended, graphene having a two-dimensional structure, a solvent, and optional additives is prepared, and the mixture is subjected to a dispersion treatment. This results in the dispersion treatment being performed in a state of relatively high viscosity, which makes it possible to suppress aggregation of the graphene. As a result, the graphene can be uniformly dispersed in the mixture.

[0071] The upper limit of the amount of adhesive resin mixed in the first step is preferably 50 parts by mass or less, more preferably 30 parts by mass or less, and particularly preferably 25 parts by mass or less, relative to 100 parts by mass of graphene having a two-dimensional structure. This allows the dispersion treatment to be performed in a state of relatively high viscosity, making it easier to disperse the graphene having a two-dimensional structure more uniformly. The lower limit of the amount of adhesive resin mixed in the first step is preferably 0.5 parts by mass or more, more preferably 1 part by mass or more, particularly preferably 2 parts by mass or more, and even more preferably 3 parts by mass or more, relative to 100 parts by mass of graphene having a two-dimensional structure.

[0072] The dispersion treatment of the mixture may be carried out by a conventionally known method, and for example, known kneading machines and dispersing machines such as a homogenizer, a bead mill, a ball mill, a jet mill, a disperser, a mixer, a kneader, an ultrasonic disperser, etc. The dispersion treatment may be carried out by using a single machine or a combination of two or more machines.

[0073] Among the above, it is preferable to use a disperser, a mixer, a jet mill, or an ultrasonic disperser for the dispersion treatment, because it is possible to prevent excessive grinding of the graphene, which would result in a significant decrease in thermal conductivity, and to uniformly disperse the graphene in the mixture while suppressing aggregation of the graphene. When the dispersion treatment of the mixture is performed using a disperser, it is preferable to perform the dispersion treatment at a rotation speed of 500 to 5,000 rpm, with stirring for 10 minutes or more, and more preferably at a rotation speed of 1,000 to 4,000 rpm, with stirring for 20 minutes or more.

[0074] The solvent used in preparing the pressure-sensitive adhesive coating solution is not particularly limited, and examples thereof include aliphatic hydrocarbons such as hexane, heptane, and cyclohexane; aromatic hydrocarbons such as toluene and xylene; halogenated hydrocarbons such as methylene chloride and ethylene chloride; alcohols such as methanol, ethanol, propanol, butanol, and 1-methoxy-2-propanol; ketones such as acetone, methyl ethyl ketone, 2-pentanone, isophorone, and cyclohexanone; esters such as ethyl acetate and butyl acetate; cellosolve-based solvents such as ethyl cellosolve; N,N-dimethylformamide, trimethyl-2-pyrrolidone, and butyl carbitol, with methyl ethyl ketone being preferred.

[0075] The upper limit of the amount of solvent mixed in the first step is preferably 10,000 parts by mass or less, more preferably 5,000 parts by mass or less, and even more preferably 2,000 parts by mass or less, relative to 100 parts by mass of graphene having a two-dimensional structure. This allows the dispersion treatment to be performed in a state of relatively high viscosity, making it easier to disperse the graphene having a two-dimensional structure more uniformly. Furthermore, the lower limit of the amount of adhesive resin mixed in the first step is preferably 200 parts by mass or more, more preferably 500 parts by mass or more, more preferably 800 parts by mass or more, and even more preferably 1,000 parts by mass or more, relative to 100 parts by mass of graphene having a two-dimensional structure. This allows the dispersion treatment to be performed well.

[0076] (2-2) Second process In the second step of this embodiment, at least the remainder of the adhesive resin and preferably a crosslinking agent are added to the premix obtained in the first step, followed by a dispersion treatment. In this second step, it is also preferable to add a solvent. The type of solvent and the conditions for the dispersion treatment are the same as those in the first step.

[0077] The amount of solvent added in the second step is not particularly limited as long as the viscosity of the resulting pressure-sensitive adhesive coating solution is within a range that allows coating, and can be appropriately selected depending on the situation. Generally, the amount is preferably such that the solids concentration of the pressure-sensitive adhesive is 2 to 50 mass%, particularly preferably 5 to 40 mass%, and even more preferably 10 to 35 mass%.

[0078] Through the above steps, a pressure-sensitive adhesive coating liquid in which graphene having a two-dimensional structure is uniformly dispersed can be obtained. By applying the pressure-sensitive adhesive coating liquid, a pressure-sensitive adhesive layer 12 in which graphene having a two-dimensional structure is uniformly dispersed can be formed.

[0079] (3) Physical properties (Raman peak intensity ratio D / G) The pressure-sensitive adhesive layer 12 in this embodiment has a wave number of 1570 cm in the absorption spectrum obtained by Raman measurement. -1The peak value of the G band absorption intensity (I G ) for the wavenumber 1250 cm -1 The peak value of the D band absorption intensity (I D ) (hereinafter sometimes referred to as "Raman peak intensity ratio D / G") is preferably 0.5 or less, more preferably 0.4 or less, particularly preferably 0.3 or less, and even more preferably 0.2 or less. When the Raman peak intensity ratio D / G is within the above range, it is understood that the graphene having a two-dimensional structure contains a good crystalline structure. This makes it easier for the pressure-sensitive adhesive layer 12 to obtain a high thermal conductivity λ due to the graphene having a two-dimensional crystalline structure. The lower limit of the Raman peak intensity ratio D / G is not particularly limited, but is usually preferably 0.001 or more.

[0080] The specific method of Raman measurement in this specification is as shown in the test examples described later. -1 The G-band peak near the wavenumber 1570 cm -1 ±100cm from the center -1 The peak intensity (I G ) indicates the relative value of the absorption intensity at the peak top obtained by measurement. -1 The D band peak near the wavenumber of 1250 cm -1 ±100cm from the center -1 The peak intensity (I D ) indicates the relative value of the absorption intensity at the peak top obtained by measurement.

[0081] 1-3.Release sheet In this embodiment, release sheet 13 is laminated so that the release surface of release sheet 13 is in contact with the surface of pressure-sensitive adhesive layer 12 that is not in contact with heat sink 11. In this specification, the release surface of the release sheet refers to the surface of the release sheet that has releasability, and includes both a surface that has been subjected to a release treatment and a surface that exhibits releasability even without being subjected to a release treatment.

[0082] Examples of materials that can be used as the release sheet 13 include polyethylene films, polypropylene films, polybutene films, polybutadiene films, polymethylpentene films, polyvinyl chloride films, vinyl chloride copolymer films, polyethylene terephthalate films, polyethylene naphthalate films, polybutylene terephthalate films, polyurethane films, ethylene vinyl acetate films, ionomer resin films, ethylene-(meth)acrylic acid copolymer films, ethylene-(meth)acrylic acid ester copolymer films, polystyrene films, polycarbonate films, polyimide films, and fluororesin films. Crosslinked films of these materials can also be used. Furthermore, laminated films of these materials can also be used.

[0083] It is preferable that a release treatment is performed on the release surface (particularly the surface in contact with the pressure-sensitive adhesive layer 12) of the release sheet 13. Examples of release agents used for the release treatment include alkyd-based, silicone-based, fluorine-based, unsaturated polyester-based, polyolefin-based, and wax-based release agents.

[0084] There are no particular restrictions on the thickness of release sheet 13, but it is usually about 20 to 150 μm.

[0085] 2. Manufacturing method When producing the heat dissipation member 1 according to this embodiment, it is preferable to first produce a pressure-sensitive adhesive sheet including the pressure-sensitive adhesive layer 12 and the release sheet 13.

[0086] In one example of manufacturing an adhesive sheet, a coating solution of adhesive is applied to the release surface of release sheet 13 and dried (heated) to form a coating layer. At this time, the release surface of another release sheet may be superimposed on the coating layer. If a curing period is required, a curing period is allowed, but if no curing period is required, the coating layer becomes adhesive layer 12 as is. In this way, the adhesive sheet is obtained.

[0087] Examples of methods that can be used to apply the adhesive coating solution include bar coating, knife coating, roll coating, blade coating, die coating, and gravure coating.

[0088] The adhesive coating solution is dried (heated) to volatilize the solvent and form a coating layer. Drying conditions are preferably 90 to 150°C for 0.5 to 30 minutes, and particularly preferably 100 to 120°C for 1 to 10 minutes.

[0089] In adhesives containing a crosslinking agent, crosslinking can usually be achieved by heat treatment (or the drying treatment described above). After the heat treatment, it is preferable to allow a curing period of about 1 to 2 weeks at room temperature (e.g., 23°C, 50% RH) as necessary.

[0090] Once the adhesive sheet is obtained as described above, adhesive layer 12 on release sheet 13 is attached to heat sink 11. If a release sheet other than release sheet 13 is present, the release sheet is peeled off from adhesive layer 12 to expose adhesive layer 12, and then adhesive layer 12 is attached to heat sink 11.

[0091] [Heat dissipation device] As shown in Figure 2, a heat dissipation device 2 according to one embodiment of the present invention comprises a heat dissipation member 1 having a heat sink 11 and an adhesive layer 12, and a heat generating member 21 to which the heat sink 11 is attached via the adhesive layer 12.

[0092] The heat dissipation member 1 of this embodiment is the heat dissipation member 1 of the above-described embodiment from which the release sheet 13 has been removed. Because the adhesive layer 12 in this heat dissipation member 1 has high thermal conductivity and adhesive strength, the heat generated by the heat-generating member 21 is well conducted through the adhesive layer 12 to the heat dissipation body 11, and is efficiently dissipated from the heat dissipation body 11 to the outside.

[0093] The heat-generating member 21 in this embodiment is a member that generates heat while performing a predetermined function, but that requires that the temperature rise be suppressed, or a member that requires that the flow of heat generated by the member be controlled in a specific direction, etc. Examples of such heat-generating member 21 include semiconductor devices such as thermoelectric conversion devices, photoelectric conversion devices, and large-scale integrated circuits, electronic devices such as LED light-emitting elements, optical pickups, and power transistors, various electronic devices such as mobile terminals and wearable terminals, batteries, electric cells, motors, and engines.

[0094] To manufacture the heat dissipating device 2, the release sheet 13 is peeled off from the adhesive layer 12 of the heat dissipating member 1, and the exposed adhesive layer 12 is then attached to the heat-generating member .

[0095] The pressure-sensitive adhesive layer 12 in the heat-dissipating device 2 according to this embodiment has excellent pump-out resistance, and therefore can prevent the pressure-sensitive adhesive from seeping out from the pressure-sensitive adhesive layer 12 even when the heat-dissipating device 2 is subjected to repeated heating and cooling cycles. As a result, contamination of the heat-dissipating device 2 and its peripheral members can be prevented, and reliability can be improved.

[0096] The above-described embodiments have been described to facilitate understanding of the present invention, and are not intended to limit the present invention. Therefore, each element disclosed in the above embodiments is intended to include all design modifications and equivalents that fall within the technical scope of the present invention.

[0097] For example, the release sheet 13 may be omitted from the heat dissipation member 1. Furthermore, the shapes of the heat dissipation body 11 and the heat-generating member 21 are not limited to those shown in Figures 1 and 2, and may be various shapes. [Example]

[0098] The present invention will be explained in more detail below with reference to examples, but the scope of the present invention is not limited to these examples.

[0099] Example 1 Five parts by mass of an acrylic acid ester polymer as an adhesive resin (5 parts by mass out of a total of 100 parts by mass; solids concentration), 14 parts by mass (solids concentration) of graphene having a two-dimensional structure (manufactured by ADEKA Corporation, product name "CNS-1A1"), and 300 parts by mass of ethyl methyl ketone as a solvent were mixed, and the mixture was dispersed using a Disper (manufactured by Primix Corporation, product name "Robomix") at 3,000 rpm for 30 minutes to prepare a preliminary mixture (Step 1). Details of the acrylic acid ester polymer and the graphene having a two-dimensional structure are as follows: Acrylic acid ester polymer: A copolymer obtained by copolymerizing 91 parts by mass of n-butyl acrylate and 9 parts by mass of acrylic acid. Weight average molecular weight: 500,000. Graphene with a two-dimensional structure: ADEKA Corporation, product name "CNS-1A1", two-dimensional crystal structure, average particle size 12 μm, thickness 50 nm or less, Raman peak intensity ratio D / G = 0.1, when measured by X-ray diffraction using a CuKα radiation source (wavelength 0.15418 nm), peaks were detected at 2θ of 26.6° and 42.4°.

[0100] To the above premix, 95 parts by mass of the same acrylic ester polymer as above (95 parts by mass out of a total of 100 parts by mass; solids concentration), 6 parts by mass (solids concentration) of a tolylene diisocyanate crosslinker (manufactured by Toyo Ink Co., Ltd., product name "BHS-8515"), and 129 parts by mass of ethyl methyl ketone as a solvent were added, and the mixture was dispersed by stirring at 3000 rpm for 30 minutes using a Disper (manufactured by Primix Corporation, product name "Robomix") (step 2), to obtain a pressure-sensitive adhesive coating solution. The solids concentration of this pressure-sensitive adhesive coating solution was 25% by mass.

[0101] The resulting adhesive coating solution was applied with an applicator to the release-treated surface of a heavy-release release sheet (manufactured by Lintec Corporation, product name "SP-PET381031"), one side of which had been treated with a silicone-based release agent. The sheet was then heated at 100°C for 1 minute and dried to form a coating layer. The coating layer was then bonded to the release-treated surface of a light-release release sheet (manufactured by Lintec Corporation, product name "SP-PET381130"), one side of which had been treated with a silicone-based release agent. The sheet was then aged for 7 days at 23°C and 50% RH to form an adhesive layer. In this way, an adhesive sheet (light-release release sheet / adhesive layer / heavy-release release sheet) with an adhesive layer thickness of 30 μm was prepared.

[0102] On the other hand, we prepared the "N45-6B" heat sink manufactured by Alpha Corporation as a heat dissipator. This heat sink is made of aluminum and has multiple heat sink plates arranged in parallel and vertical rows on a square base in plan view. The size of the base's bottom surface is 45mm x 45mm.

[0103] The pressure-sensitive adhesive sheet was cut to a size of 45 mm x 45 mm, and the light release release sheet was then peeled off, leaving the exposed pressure-sensitive adhesive layer attached to the bottom surface of the heat sink base. In this way, a heat dissipation component consisting of a heat sink / pressure-sensitive adhesive layer / heavy release release sheet was produced.

[0104] Example 2 Pressure-sensitive adhesive sheets and heat dissipation members were produced in the same manner as in Example 1, except that the amounts of graphene having a two-dimensional structure and crosslinking agent were changed as shown in Table 1.

[0105] Example 3 An acrylic adhesive (manufactured by Soken Chemical & Engineering Co., Ltd., product name "SK Dyne 1502") was used as the acrylic acid ester polymer, and adhesive sheets and heat dissipation members were manufactured in the same manner as in Example 1, except that the amount of crosslinking agent was changed as shown in Table 1.

[0106] Example 4 As the acrylic acid ester polymer, a copolymer (weight average molecular weight: 350,000) obtained by copolymerizing 80 parts by mass of 2-ethylhexyl acrylate and 20 parts by mass of hydroxyethyl acrylate was prepared.

[0107] An adhesive sheet and a heat dissipation member were produced in the same manner as in Example 1, except that the above-mentioned acrylic acid ester polymer was used, the amount of graphene having a two-dimensional structure was changed as shown in Table 1, and 1 part by mass of a hexamethylene diisocyanate-based crosslinking agent (manufactured by Tosoh Corporation, product name "Coronate HL") was used as the crosslinking agent.

[0108] Comparative Example 1 Pressure sensitive adhesive sheets and heat dissipation members were produced in the same manner as in Example 4, except that the amount of crosslinking agent was changed as shown in Table 1 (no crosslinking agent was used).

[0109] Comparative Example 2 Pressure-sensitive adhesive sheets and heat dissipation members were produced in the same manner as in Example 1, except that the amount of graphene having a two-dimensional structure was changed as shown in Table 1 (graphene having a two-dimensional structure was not used).

[0110] Comparative Example 3 As the acrylic acid ester polymer, a copolymer (weight average molecular weight: 530,000) obtained by copolymerizing 59.4 parts by mass of n-butyl acrylate, 29.7 parts by mass of 2-ethylhexyl acrylate, 9.9 parts by mass of vinyl acetate, and 1 part by mass of acrylic acid was prepared.

[0111] Pressure-sensitive adhesive sheets and heat dissipation members were produced in the same manner as in Example 1, except that the above-mentioned acrylic acid ester polymer was used, the amount of graphene having a two-dimensional structure was changed as shown in Table 1, and 40 parts by mass of an aziridine-based crosslinking agent (manufactured by Toyo Ink Mfg. Co., Ltd., product name "Orivine BXX5134") was used as the crosslinking agent.

[0112] [Test Example 1] <Measurement of thermal conductivity> Square samples measuring 5 mm on each side were obtained from the adhesive layers of the adhesive sheets produced in the Examples and Comparative Examples. The thermal conductivity (W / m K) of the samples (adhesive layers) was measured in accordance with ISO 22007-3 at 23°C and 50% RH using a thermal diffusivity and thermal conductivity measuring device (manufactured by Ai-Phase Corporation, product name "ai-phase mobile"). The results are shown in Table 2.

[0113] [Test Example 2] <Measurement of probe tack value> The light release release sheet was peeled off from the pressure-sensitive adhesive sheets produced in the Examples and Comparative Examples, and the exposed pressure-sensitive adhesive layer was attached to a glass plate. The heavy release release sheet was then peeled off from the pressure-sensitive adhesive layer on the glass plate. The pressure-sensitive adhesive layer on the glass plate was measured for probe tack value (mN / 5mmΦ) using a probe with a diameter of 5mm (5mmΦ) and a probe tack tester (manufactured by Tester Sangyo Co., Ltd., product name "TE-6001 Probe Tack Tester") in accordance with JIS Z0237:2009 under the following measurement conditions. The results are shown in Table 2. Load: 200gf / cm 2 Contact time: 1 second Test speed: 1cm / sec

[0114] [Test Example 3] <Measurement of holding power> The pressure-sensitive adhesive sheets produced in the Examples and Comparative Examples were cut to a size of 25 mm x 100 mm, and the light-release release sheet was peeled off. The exposed pressure-sensitive adhesive layer was attached to a stainless steel plate (SUS380 plate) in an environment of 23°C and 50% RH so that the adhesive area was 25 mm x 25 mm, and a 2 kg roller was moved back and forth five times to press the exposed adhesive layer onto the plate, which was used as a test specimen.

[0115] Using the obtained test specimen, a test was conducted in accordance with the JIS Z0237 method for measuring holding strength, at 40°C under dry conditions, with a load of 9.8 N applied, and the amount of slippage up to 70,000 seconds was confirmed. If the amount of slippage after 70,000 seconds was 0 mm, i.e., if no slippage occurred up to 70,000 seconds, this is indicated as "70,000NC" in the table. If slippage occurred, the amount of slippage (mm) after 70,000 seconds is shown. If the test specimen fell off the stainless steel plate during the test, the time (s) from the start of the test to the falloff is shown. The results are shown in Table 2.

[0116] The result of Example 4 was 45,000 (s) (fell off after 45,000 seconds), but no displacement occurred until 40,000 seconds later.

[0117] [Test Example 4] <Measurement of thermal resistance> The pressure-sensitive adhesive sheets produced in the examples and comparative examples were cut to a size of 45 mm x 45 mm and used as test pieces. A brass block measuring 45 mm x 45 mm and 50 mm thick, a phenolic resin plate measuring 45 mm x 45 mm and 1 mm thick (manufactured by Risho Kogyo Co., Ltd., product name "PS1143S"), a copper plate measuring 45 mm x 45 mm and 1 mm thick, and the heat sink used in the examples were also prepared.

[0118] A structure was created by stacking, from bottom to top, a brass block, a test piece, a phenolic resin plate, a test piece, a copper plate, and a heat sink. The structure was placed on a hot plate heated to 50°C, allowing heat to flow from the brass block to the heat sink. At this time, the temperatures of the brass block and the copper plate were measured, and the thermal resistance (m 2 The thermal resistance (K / W) when the test specimen was installed was calculated.

[0119] A structure was also prepared by stacking a brass block, a phenolic resin plate, a copper plate, and a heat sink in this order from the bottom up. The structure was placed on a hot plate heated to 50°C, and the thermal resistance (m 2 The thermal resistance (K / W) (when the test specimen was not installed) was calculated.

[0120] Based on the above results, the rate of change in thermal resistance (%) was calculated using the following formula: The results are shown in Table 2. Thermal resistance change rate = (thermal resistance when test piece is installed / thermal resistance when test piece is not installed) x 100 From the viewpoint of thermal conductivity, this thermal resistance change rate (%) is preferably 90% or less, particularly preferably 85% or less, and even more preferably 75% or less. When the thermal resistance change rate (%) is in the above range, heat from the heat-generating component can be efficiently released.

[0121] [Test Example 5] <Evaluation of pump-out> The pressure-sensitive adhesive sheets produced in the Examples and Comparative Examples were cut into circles with a diameter of 5 cm. The pressure-sensitive adhesive layer of the pressure-sensitive adhesive sheet was sandwiched between two glass plates measuring 7 cm x 7 cm and 2 cm thick to produce a structure. A 200 g weight was placed on this structure, and this was used as a sample.

[0122] The above samples were subjected to a thermal shock test using a thermal shock device (manufactured by Espec Corporation, product name "TSE-11"). Specifically, 200 thermal cycles were performed, with one cycle consisting of "-40°C for 15 minutes → 120°C for 15 minutes". The area (mm ) of the adhesive layer on the sample before and after the test was 2 ) was measured, and the area change rate (%) was calculated using the following formula. Area change rate = (area after test / area before test) x 100 Based on the calculated area change rate (%), the pump-out resistance was evaluated according to the following criteria. The results are shown in Table 2. ○…Area change rate is less than 101% △: Area change rate is 101% or more and less than 105% ×: Area change rate is 105% or more

[0123] [Table 1]

[0124] [Table 2]

[0125] As can be seen from Table 2, the pressure-sensitive adhesive layers of the pressure-sensitive adhesive sheets produced in the examples were excellent in thermal conductivity and pump-out resistance. [Industrial Applicability]

[0126] The heat dissipation member according to the present invention can be suitably used, for example, to cool a heat-generating electronic device. [Explanation of symbols]

[0127] 1...Heat dissipation member 11...Heat sink 12...Adhesive layer 13...Release sheet 2…Heat dissipation device 21...heat generating member

Claims

1. A heat dissipation member comprising a heat dissipation body and an adhesive layer adhered to the heat dissipation body, The thermal conductivity λ of the pressure-sensitive adhesive layer is 0.5 W / m k or more and 10 W / m k or less, a probe tack value of the surface of the pressure-sensitive adhesive layer that does not contact the heat sink is 2 mN / 5 mmΦ or more and 10 mN / 5 mmΦ or less; When the pressure-sensitive adhesive layer is attached to a SUS380 plate, the holding strength according to JIS Z0237:2009 is 0 mm as the amount of displacement measured under the conditions of a test temperature of 40°C, an attachment area of ​​25 mm x 25 mm, a load of 9.8 N, and a holding time of 40,000 seconds. A heat dissipation member characterized by:

2. 2. The heat dissipation member according to claim 1, wherein the pressure-sensitive adhesive layer has a probe tack value of 2 mN / 5 mmΦ or more and 10 mN / 5 mmΦ or less on the surface that comes into contact with the heat dissipation body.

3. 2. The heat dissipation member according to claim 1, wherein the thickness of the adhesive layer is 10 [mu]m or more and 50 [mu]m or less.

4. The heat dissipation member according to claim 1 , wherein the adhesive layer contains an adhesive resin and graphene having a two-dimensional structure.

5. 5. The heat dissipation member according to claim 4, wherein the adhesive resin is crosslinked with a crosslinking agent.

6. 5. The heat dissipation member according to claim 4, wherein a content of the graphene having a two-dimensional structure in the pressure-sensitive adhesive layer is 5 parts by mass or more and 100 parts by mass or less with respect to 100 parts by mass of the pressure-sensitive adhesive resin.

7. 2. The heat dissipation member according to claim 1, wherein the heat dissipation body is a heat sink having a plurality of heat dissipation plates.

8. A heat-generating member; The heat dissipation member according to any one of claims 1 to 7. A heat dissipation device comprising: The heat dissipation member is adhered to the heat generating member via the adhesive layer. A heat dissipating device characterized by:

9. the heat-generating member is an electronic component body, The heat-dissipating device is a heat-dissipating electronic component. The heat dissipating device of claim 8.

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