Heat conducting member

Abstract

The present application provides a heat conducting member having both high thermal conductivity and low hardness. The heat conducting member is a laminate provided with a plurality of layers, the plurality of layers including a first layer and a second layer laminated at a position where they contact each other. The first layer is composed of a first thermal conductivity composition, the first thermal conductivity composition containing at least a first acrylic adhesive, a first thermal conductivity filler, and a dispersing agent. The dispersing agent contains at least one of a linear polyester having a weight average molecular weight of 1000 to 2500 and having a phosphoric acid at a terminal end, and a polyester-polyether copolymer having a weight average molecular weight of 1000 to 2500 and having a phosphoric acid at a terminal end.

Description

TECHNICAL FIELD

[0001] The present application relates to a heat transfer member. BACKGROUND

[0002] A heat transfer sheet is known to have a low-hardness layer and a reinforcing layer, the reinforcing layer being laminated on one or both surfaces of the low-hardness layer (see, for example, Patent Document 1). In the heat transfer sheet described in Patent Document 1, the low-hardness layer contains an acrylic polymer, silicon carbide, aluminum hydroxide, magnesium hydroxide, and a plasticizer.

[0003] PRIOR ART DOCUMENTS

[0004] PATENT DOCUMENTS

[0005] Patent Document 1: Japanese Patent No. 6710828

[0006] Generally, in the heat transfer sheet described above, the thermal conductivity of the heat transfer sheet can be increased by increasing the proportion of the thermally conductive filler in the low-hardness layer. However, if the proportion of the thermally conductive filler is increased, the low-hardness layer tends to become hard. Therefore, the softness of the heat transfer sheet decreases, and the heat transfer sheet is not easily deformed. For example, when the heat transfer sheet is sandwiched between an electronic component as a heat source and a heat sink, the heat transfer sheet is not easily deformed even if it is compressed. As a result, the contact pressure on the electronic component increases, and the electronic component is likely to be subjected to a load.

[0007] On the other hand, if the proportion of the plasticizer in the low-hardness layer is increased, the hardness of the low-hardness layer can be decreased. However, if the proportion of the plasticizer is increased, the adhesion of the low-hardness layer tends to increase. Therefore, when the heat transfer sheet is manufactured, it is difficult to apply, for example, cutting processing, and the productivity decreases. Also, when the heat transfer sheet is used, for example, the cutting positions are likely to adhere to each other, and it is difficult to peel the cutting positions, and the workability decreases. In addition, if the proportion of the plasticizer is increased, oil bleeding is also likely to occur. Therefore, there is a problem in that it is difficult to balance and improve the thermal conductivity and the hardness of the heat transfer sheet. SUMMARY

[0008] One aspect of the present application preferably provides a heat transfer member that has both high thermal conductivity and low hardness.

[0009] TECHNICAL MEANS FOR SOLVING THE PROBLEM

[0010] The heat transfer member of one aspect of the present invention is a laminate provided with a plurality of layers, the plurality of layers including a first layer and a second layer laminated at a position where they contact each other. The first layer is composed of a first heat transfer composition including at least a first acrylic-based adhesive, a first heat transfer filler, and a dispersant. The second layer is composed of a second heat transfer composition including at least a second acrylic-based adhesive and a second heat transfer filler. In the first heat transfer composition, 500 to 1,200 parts by mass of the first heat transfer filler and 0.2 to 5 parts by mass of the dispersant are blended with respect to 100 parts by mass of the first acrylic-based adhesive. In the second heat transfer composition, 200 to 400 parts by mass of the second heat transfer filler is blended with respect to 100 parts by mass of the second acrylic-based adhesive. The dispersant includes at least one of a linear polyester having a weight average molecular weight of 1,000 to 2,500 and having a phosphoric acid at a terminal end and a polyester-polyether copolymer having a weight average molecular weight of 1,000 to 2,500 and having a phosphoric acid at a terminal end.

[0011] The heat transfer member thus configured has both high heat transfer rate and low hardness, compared with conventional products. Also, the adhesion of the first layer can be suppressed, and the first layer can be prevented from emitting oil, compared with conventional products.

[0012] The first acrylic-based adhesive includes at least an acrylic polymer and a plasticizer, and 15 to 45 parts by mass of the plasticizer is blended with respect to 100 parts by mass of the acrylic polymer.

[0013] The first heat transfer filler includes at least silicon carbide having an average particle diameter of 60 to 100 μm, first spherical alumina having an average particle diameter of 70 to 100 μm, second spherical alumina having an average particle diameter of 1 to 30 μm, and first magnesium hydroxide having an average particle diameter of 0.5 to 2 μm. The second heat transfer filler includes, as essential components, aluminum hydroxide having an average particle diameter of 5 to 50 μm, and can include, as optional components, second magnesium hydroxide having an average particle diameter of 0.5 to 2 μm. In the first heat transfer filler, 20 to 40 parts by mass of the silicon carbide, 20 to 50 parts by mass of the first spherical alumina, 20 to 50 parts by mass of the second spherical alumina, and 1 to 10 parts by mass of the first magnesium hydroxide are blended with respect to 100 parts by mass of the first heat transfer filler. In the second heat transfer filler, 90 to 100 parts by mass of the aluminum hydroxide and 0 to 10 parts by mass of the second magnesium hydroxide are blended with respect to 100 parts by mass of the second heat transfer filler.

[0014] The first layer is configured to have an ASKER C hardness of 0.1 to 22 and a thermal conductivity of 2 to 15 W / m·K.

[0015] The plurality of layers includes a third layer, which is opposite to the second layer across the first layer, and is in contact with and deposited on the side of the first layer facing away from the second layer. The third layer is composed of a resin film with a thickness of 1 to 15 μm. Attached Figure Description

[0016] FIG. 1A A three-dimensional view is provided to roughly illustrate the heat-conducting components. FIG. 1B An explanatory diagram showing the usage status of a heat-conducting component.

[0017] Explanation of reference numerals in the attached figures

[0018] 1…heat conduction component, 11…first layer, 12…second layer, 13…third layer, 21…electronic circuit board, 22…electronic component, 23…metal plate. Detailed Implementation

[0019] Next, examples of embodiments of the aforementioned heat-conducting components will be given for illustration.

[0020] (1) Construction of heat-conducting components

[0021] like FIG. 1A As shown, the heat-conducting component 1 is a laminated body with multiple layers, including a first layer 11, a second layer 12, and a third layer 13. The first layer 11 and the second layer 12 are laminated at positions where they are in contact with each other. The third layer 13 is opposite to the second layer 12 across the first layer 11, and is in contact with and laminated with the first layer 11 on the side of the first layer 11 facing away from the second layer 12.

[0022] The first layer 11 is composed of a first thermally conductive component. The first thermally conductive component contains at least a first acrylic adhesive, a first thermally conductive filler, and a dispersant. The amount of the first thermally conductive filler, relative to 100 parts by mass of the first acrylic adhesive, is 500 to 1200 parts by mass, preferably 600 to 1000 parts by mass.

[0023] If the blending ratio of the first thermally conductive filler is 500 parts by mass or more, the first layer 11 can be a layer having excellent thermal conductivity compared to a case where the blending ratio of the first thermally conductive filler is less than 500 parts by mass. If the blending ratio of the first thermally conductive filler is 600 parts by mass or more, the first layer 11 can be a layer having more excellent thermal conductivity. On the other hand, if the blending ratio of the first thermally conductive filler is 1200 parts by mass or less, the hardness of the first layer 11 can be suppressed from being excessively high compared to a case where the blending ratio of the first thermally conductive filler is more than 1200 parts by mass. If the blending ratio of the first thermally conductive filler is 1000 parts by mass or less, the hardness of the first layer 11 can be more low.

[0024] In the present embodiment, the first acrylic adhesive contains at least an acrylic polymer and a plasticizer. The blending amount of the plasticizer is 15 to 45 parts by mass with respect to 100 parts by mass of the acrylic polymer. If the blending ratio of the plasticizer is 15 parts by mass or more, the first layer 11 can be low in hardness compared to a case where the blending ratio of the plasticizer is less than 15 parts by mass. If the blending ratio of the plasticizer is 45 parts by mass or less, the first layer 11 can be suppressed from having excessive tackiness, and can be suppressed from being oily.

[0025] The acrylic polymer can be formed by, for example, polymerizing or copolymerizing an acrylic resin containing a (meth)acrylate-containing monomer and a (meth)acrylate.

[0026] The (meth)acrylate can include, for example, ethyl (meth)acrylate, n-propyl (meth)acrylate, isopropyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, n-hexyl (meth)acrylate, n-pentyl (meth)acrylate, isopentyl (meth)acrylate, octyl (meth)acrylate, isooctyl (meth)acrylate, isotetradecyl (meth)acrylate, lauryl (meth)acrylate, nonyl (meth)acrylate, isononyl (meth)acrylate, isodecyl (meth)acrylate, tridecyl (meth)acrylate, stearyl (meth)acrylate, isostearyl (meth)acrylate, and the like. These can be used alone or two or more kinds thereof can be used in combination.

[0027] The acrylic polymer can be obtained by heating and curing the acrylic resin described above with the addition of additives such as a polyfunctional monomer, a polymerization initiator, and a plasticizer.

[0028] Examples of the polyfunctional monomer include those having two or more (meth)acryloyl groups in a molecule. Examples of the difunctional (meth)acrylate monomer having two (meth)acryloyl groups in a molecule include 1,3-butanediol di(meth)acrylate, 1,4-butanediol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, 1,9-nonanediol di(meth)acrylate, neopentyl glycol di(meth)acrylate, dicyclopentanyl acrylate, 2-ethyl-2-butyl-propanediol (meth)acrylate, neopentyl glycol-modified trimethylolpropane di(meth)acrylate, stearic acid-modified pentaerythritol diacrylate, polypropylene glycol di(meth)acrylate, 2,2-bis[4-(meth)acryloyloxydiethoxyphenyl]propane, 2,2-bis[4-(meth)acryloyloxypropoxyphenyl]propane, 2,2-bis[4-(meth)acryloyloxytetraethoxyphenyl]propane, and the like.

[0029] Examples of the tri-functional (meth)acrylate monomer include trimethylolpropane tri(meth)acrylate, tris[(meth)acryloyloxyethyl] isocyanurate, and the like. Examples of the (meth)acrylate monomer having a functionality of four or more include dimethylolpropane tetra(meth)acrylate, pentaerythritol tetra(meth)acrylate, pentaerythritol ethoxylate tetra(meth)acrylate, dipentaerythritol penta(meth)acrylate, dipentaerythritol hexa(meth)acrylate, and the like.

[0030] Among these polyfunctional monomers, 1,6-hexanediol di(meth)acrylate and the like are preferred.

[0031] The above polyfunctional monomer is preferably blended in an amount of 0.005 to 0.015 parts by mass relative to 20 to 25 parts by mass of the acrylic resin in the first layer 11.

[0032] Examples of the polymerization initiator include organic peroxides such as di-(4-tert-butylcyclohexyl) peroxydicarbonate, lauroyl peroxide, tertiary amyl peroxy-2-ethylhexanoate, benzoyl peroxide, tert-butyl peroxy-2-ethylhexanoate, and the like. Among these polymerization initiators, di-(4-tert-butylcyclohexyl) peroxydicarbonate is preferred.

[0033] The polymerization initiator is preferably blended in an amount of 0.1 to 0.3 parts by mass relative to 20 to 25 parts by mass of the acrylic resin.

[0034] As the plasticizer, a general-purpose plasticizer can be used, and a phthalic acid-based plasticizer, an adipic acid-based plasticizer, a phosphoric acid-based plasticizer, a trimellitic acid-based plasticizer, a polyester-based plasticizer, or the like can be suitably used. These plasticizers can be used alone or in combination of two or more. By adjusting the plasticizer, the first layer 11 can be made low in hardness, and the heat transfer member 1 can be made soft.

[0035] As an additive, an antioxidant can be added to the first layer 11. As the antioxidant, a phenol-based antioxidant having a radical capturing action can be used, for example. If this antioxidant is added, the polymerization reaction of the acrylic resin can be suppressed at the time of manufacturing the sheet, and thus the hardness of the sheet can be reduced.

[0036] The antioxidant is preferably added in an amount of 0.05 to 0.10 parts by mass with respect to 20 to 25 parts by mass of the acrylic resin. If the amount of the antioxidant is small, the polymerization reaction of the acrylic resin proceeds, and the hardness of the sheet increases. If the amount of the antioxidant is large, the hardening of the resin tends to be inhibited.

[0037] In the present embodiment, the first heat-conductive filler contains at least silicon carbide having an average particle diameter of 60 to 100 μm, first spherical alumina having an average particle diameter of 70 to 100 μm, second spherical alumina having an average particle diameter of 1 to 30 μm, and first magnesium hydroxide having an average particle diameter of 0.5 to 2 μm. The average particle diameter in the present application is an average particle diameter D50 obtained by a laser diffraction method or the like.

[0038] If the average particle diameter of the silicon carbide is 60 μm or more, the bonding strength between the first layer 11 and the second layer 12 can be improved as compared with the case where the average particle diameter of the silicon carbide is less than 60 μm. If the average particle diameter of the silicon carbide is 100 μm or less, the particles of the silicon carbide can be suppressed from being detached from the heat transfer member 1 at the time of manufacturing the heat transfer member 1 as compared with the case where the average particle diameter of the silicon carbide is more than 100 μm.

[0039] The first spherical alumina and the second spherical alumina are two kinds of spherical aluminas having different average particle diameters. If these two kinds of spherical aluminas are added, the spherical alumina having a small average particle diameter is filled between the particles of the silicon carbide and between the particles of the spherical alumina having a large average particle diameter. By this, the contact portions of the particles with each other can be increased between the particles constituting the heat-conductive filler, and the heat transfer performance of the first layer 11 can be improved.

[0040] If the average particle diameter of the first spherical alumina is 70 μm or more and the average particle diameter of the second spherical alumina is 30 μm or less, the particle diameter difference between the first spherical alumina and the second spherical alumina can be made sufficiently large. By this, the effect of blending the two kinds of spherical alumina having different average particle diameters becomes remarkable compared with the case where the particle diameter difference is small. If the average particle diameter of the first spherical alumina is 100 μm or less, the first spherical alumina can be inhibited from being detached from the heat transfer member 1 at the time of manufacturing the heat transfer member 1 compared with the case where the average particle diameter of the first spherical alumina exceeds 100 μm. If the average particle diameter of the second spherical alumina is 1 μm or more, the viscosity of the first heat conductive filler can be inhibited from becoming excessively high compared with the case where the average particle diameter of the second spherical alumina is less than 1 μm.

[0041] Both the first spherical alumina and the second spherical alumina are low-sodium alumina. The low-sodium alumina according to the present embodiment has a sodium component as an impurity inhibited to 0.1% by mass or less in terms of Na2O.

[0042] If the average particle diameter of the first magnesium hydroxide is 0.5 to 2 μm, the viscosity of the first heat conductive filler can be appropriately increased.

[0043] The dispersant contains at least one of a linear polyester having a weight average molecular weight of 1000 to 2500 and having a phosphoric acid at the terminal and a polyester-polyether copolymer having a weight average molecular weight of 1000 to 2500 and having a phosphoric acid at the terminal. By blending such a dispersant, the dispersibility of the first heat conductive filler in the first acrylic binder can be improved. Therefore, the thermal conductivity of the first layer 11 can be increased compared with the case where the same dispersant is not blended. The blending amount of the dispersant is 0.2 to 5 parts by mass, preferably 0.2 to 2.0 parts by mass, with respect to 100 parts by mass of the acrylic polymer.

[0044] The first layer 11 configured as described above has, in the case of the present embodiment, an ASKER C hardness of 0.1 to 22. By this, the hardness of the first layer 11 can be made sufficiently low. Also, the first layer 11 has, in the case of the present embodiment, a thermal conductivity of 2 to 15 W / m-K. By this, the thermal conductivity of the first layer 11 can be made sufficiently high.

[0045] The second layer 12 is configured of a second heat conductive composition containing at least a second acrylic binder and a second heat conductive filler. In this second heat conductive composition, 200 to 400 parts by mass, preferably 250 to 350 parts by mass, of the second heat conductive filler is blended with respect to 100 parts by mass of the second acrylic binder.

[0046] In this embodiment, the second acrylic adhesive contains at least an acrylic polymer. The acrylic polymer can be the same as that contained in the first acrylic adhesive. However, the second layer 12 is a layer with a higher hardness than the first layer 11. Therefore, for example, the amount of multifunctional monomers can be greater than that in the first layer 11; for example, it is preferable to incorporate 0.05 to 0.10 parts by weight of multifunctional monomers in the second layer 12.

[0047] In this embodiment, the second thermally conductive filler comprises, by weight ratio of 90 to 100 parts by weight of aluminum hydroxide as an essential component and 0 to 10 parts by weight of magnesium hydroxide as an optional component, comprising 100 parts by weight of the second thermally conductive filler. That is, 100 parts by weight of the second thermally conductive filler may consist of 100 parts by weight of the essential component aluminum hydroxide, or a subset of magnesium hydroxide, comprising less than 10 parts by weight of the essential component aluminum hydroxide, may be incorporated as an optional component, such that the total amount of aluminum hydroxide and magnesium hydroxide is 100 parts by weight.

[0048] The second layer 12 thus constructed is a layer with higher hardness than the first layer 11 and lower adhesion than the first layer 11. Therefore, if the second layer 12 covers one side of the first layer 11, adhesion on one side of the heat conduction member 1 can be suppressed compared to the heat conduction member without the second layer 12.

[0049] The third layer 13 is composed of a resin film with a thickness of 1 to 15 μm. Any resin can be used as long as it does not excessively impede the thermal conductivity of the heat-conducting component 1; however, an example is a polyester film such as PET film. PET is an abbreviation for polyethylene terephthalate.

[0050] The third layer 13 is a layer with higher hardness than the first layer 11 and lower adhesion than the first layer 11. Therefore, if the third layer 13 covers one side of the first layer 11, the adhesion of one side of the heat conduction member 1 can be suppressed compared to the heat conduction member without the third layer 13.

[0051] For example, the heat-conducting component 1 constructed as described above FIG. 1B As shown, an electronic component 22 is mounted between one side of an electronic circuit board 21 and a metal plate 23 that constitutes the housing of the electronic device. In this way, the heat generated by the electronic component 22 is conducted to the metal plate 23 via the heat conduction member 1, thereby promoting heat dissipation from the electronic component 22. FIG. 1B FIG. 1A FIG. 1B In the example, the second layer 12 is in contact with the metal plate 23 and the third layer 13 is in contact with the electronic component 22, but it is also possible to have the second layer 12 in contact with the electronic component 22 and the third layer 13 in contact with the metal plate 23.

[0052] The thickness of the first layer 11 is preferably 0.7 to 5.9 mm. The thickness of the second layer 12 is preferably 0.1 to 0.3 mm. By setting the thickness of the first layer 11 and the second layer 12 to be equal to or greater than the lower limit value described above, the thermal conduction member 1 can be prevented from breaking when an external force is applied to the thermal conduction member 1. Also, by setting the thickness of the first layer 11 and the second layer 12 to be equal to or less than the upper limit value described above, good thermal conduction performance can be exhibited.

[0053] (2) Example of manufacturing the thermal conduction member

[0054] Next, an example of manufacturing the thermal conduction member will be described.

[0055] (2.1) Example of manufacturing the first layer

[0056] [Example 1]

[0057] A first thermal conductive filler was prepared by mixing 29.14 parts by mass of silicon carbide having an average particle diameter of 60 to 100 μm, 34.30 parts by mass of first spherical alumina having an average particle diameter of 70 to 100 μm, 32.65 parts by mass of second spherical alumina having an average particle diameter of 1 to 30 μm, and 3.91 parts by mass of first magnesium hydroxide having an average particle diameter of 0.5 to 2 μm.

[0058] Next, for 100 parts by mass of the first acrylic-based adhesive, 671.58 parts by mass of the first thermal conductive filler described above and 0.62 parts by mass of a dispersant were prepared to prepare a first thermal conductive composition. As the first acrylic-based adhesive, a composition in which 22.52 parts by mass of a plasticizer was prepared for 100 parts by mass of the first acrylic-based adhesive was used.

[0059] The first thermal conductive composition described above was formed into a sheet shape to obtain a molded product corresponding to the first layer 11. The ASKER C hardness and the thermal conductivity were measured to obtain an ASKER C hardness of 3 and a thermal conductivity of 2.369 W / m-K.

[0060] [Example 2]

[0061] For 100 parts by mass of the first acrylic-based adhesive, 852.81 parts by mass of the first thermal conductive filler identical to that of the above-described Example 1 and 0.57 parts by mass of a dispersant were prepared to prepare a first thermal conductive composition. As the first acrylic-based adhesive, a composition in which 22.40 parts by mass of a plasticizer was prepared for 100 parts by mass of the first acrylic-based adhesive was used.

[0062] The first thermal conductive composition described above was formed into a sheet shape to obtain a molded product corresponding to the first layer 11. The ASKER C hardness and the thermal conductivity were measured to obtain an ASKER C hardness of 7 and a thermal conductivity of 3.372 W / m-K.

[0063] [Example 3]

[0064] For 100 parts by mass of the first acrylic adhesive, 948.58 parts by mass of the first thermally conductive filler and 0.63 parts by mass of the dispersant were prepared in the same manner as in Embodiment 1 to prepare a first thermally conductive composition. As the first acrylic adhesive, a composition in which 22.49 parts by mass of the plasticizer was prepared for 100 parts by mass of the first acrylic adhesive was used.

[0065] The first thermally conductive composition was formed into a sheet shape to obtain a molded product corresponding to the first layer 11. The ASKER C hardness and the thermal conductivity were measured to obtain an ASKER C hardness of 7 and a thermal conductivity of 3.899 W / m-K.

[0066] [Comparative Example 1]

[0067] For 100 parts by mass of the first acrylic adhesive, 1302.10 parts by mass of the first thermally conductive filler and 0.56 parts by mass of the dispersant were prepared in the same manner as in Embodiment 1 to prepare a first thermally conductive composition. As the first acrylic adhesive, a composition in which 22.51 parts by mass of the plasticizer was prepared for 100 parts by mass of the first acrylic adhesive was used.

[0068] The first thermally conductive composition was formed into a sheet shape to obtain a molded product corresponding to the first layer 11. The ASKER C hardness and the thermal conductivity were measured to obtain an ASKER C hardness of 29 and a thermal conductivity of 5.124 W / m-K. By preparing the first thermally conductive filler in a proportion of 1302.10 parts by mass, the ASKER C hardness was 29.

[0069] [Comparative Example 2]

[0070] For 100 parts by mass of the first acrylic adhesive, 853.29 parts by mass of the first thermally conductive filler were prepared in the same manner as in Embodiment 1 to prepare a first thermally conductive composition. As the first acrylic adhesive, a composition in which 22.40 parts by mass of the plasticizer was prepared for 100 parts by mass of the first acrylic adhesive was used.

[0071] The first thermally conductive composition was formed into a sheet shape to obtain a molded product corresponding to the first layer 11. The ASKER C hardness was measured to obtain an ASKER C hardness of 29. The amount of the first thermally conductive filler was close to that in Embodiment 2, but since the dispersant was not prepared, the ASKER C hardness was 29.

[0072] [Comparative Example 3]

[0073] For 100 parts by mass of the first acrylic adhesive, 853.29 parts by mass of the first thermally conductive filler identical to that of the above-described Embodiment 1 was prepared to prepare a first thermally conductive composition. As the first acrylic adhesive, a composition in which 38.94 parts by mass of a plasticizer was prepared for 100 parts by mass of the first acrylic adhesive was used.

[0074] The above-described first thermally conductive composition was formed into a sheet shape to obtain a molded product corresponding to the first layer 11. ASKER C hardness was measured to obtain ASKER C hardness of 24. The preparation amount of the first thermally conductive filler was close to that of Example 2, and the preparation amount of the plasticizer was increased compared to Comparative Example 2, but since the dispersant was not prepared, the ASKER C hardness was 24.

[0075] [Comparative Example 4]

[0076] For 100 parts by mass of the first acrylic adhesive, 853.29 parts by mass of the first thermally conductive filler identical to that of the above-described Embodiment 1 was prepared to prepare a first thermally conductive composition. As the first acrylic adhesive, a composition in which 38.94 parts by mass of a plasticizer was prepared for 100 parts by mass of the first acrylic adhesive was used.

[0077] The above-described first thermally conductive composition was formed into a sheet shape to obtain a molded product corresponding to the first layer 11. ASKER C hardness was measured to obtain ASKER C hardness of 24. The preparation amount of the first thermally conductive filler was close to that of Example 2, and the preparation amount of the plasticizer was increased compared to Comparative Example 2, but since the dispersant was not prepared, the ASKER C hardness was 24.

[0078] [Comparative Example 4]

[0079] For 100 parts by mass of the first acrylic adhesive, 853.29 parts by mass of the first thermally conductive filler identical to that of the above-described Embodiment 1 was prepared to prepare a first thermally conductive composition. As the first acrylic adhesive, a composition in which 38.94 parts by mass of a plasticizer was prepared for 100 parts by mass of the first acrylic adhesive was used.

[0080] The above-described first thermally conductive composition was formed into a sheet shape to obtain a molded product corresponding to the first layer 11. ASKER C hardness was measured to obtain ASKER C hardness of 24. The preparation amount of the first thermally conductive filler was close to that of Example 2, and the preparation amount of the plasticizer was increased compared to Comparative Example 2, but since the dispersant was not prepared, the ASKER C hardness was 24.

[0081] [Comparative Example 4]

[0082] For 100 parts by mass of the first acrylic adhesive, 852.72 parts by mass of the first thermally conductive filler described above and 0.57 parts by mass of the dispersant were compounded to prepare a first thermally conductive composition. The composition compounded with 38.94 parts by mass of the plasticizer for 100 parts by mass of the first acrylic adhesive was used as the first acrylic adhesive.

[0083] The first thermally conductive composition described above was formed into a sheet shape to obtain a molded product corresponding to the first layer 11. The ASKER C hardness and the thermal conductivity were measured to obtain an ASKER C hardness of 7 and a thermal conductivity of 3.354 W / m-K.

[0084] (2.2) Production Example of the Second Layer

[0085] [Example 6]

[0086] Aluminum hydroxide having an average particle diameter of 5 to 50 μm was used as the second thermally conductive filler, and for 100 parts by mass of the second acrylic adhesive, 281.10 parts by mass of the second thermally conductive filler described above was compounded to prepare a second thermally conductive composition. An acrylic polymer was used as the second acrylic adhesive.

[0087] The second thermally conductive composition described above was formed into a sheet shape to obtain a molded product corresponding to the second layer 12. The ASKER C hardness and the thermal conductivity were measured to obtain an ASKER C hardness of 45 and a thermal conductivity of 1.04 W / m-K.

[0088] [Example 7]

[0089] A second thermally conductive filler was prepared by mixing 263.67 parts by weight of aluminum hydroxide having an average particle diameter of 5 to 50 μm and 17.14 parts by weight of the second magnesium hydroxide having an average particle diameter of 0.5 to 2 μm. For 100 parts by mass of the second acrylic adhesive, 280.81 parts by mass of the second thermally conductive filler described above was compounded to prepare a second thermally conductive composition. An acrylic polymer was used as the second acrylic adhesive.

[0090] The second thermally conductive composition described above was applied to the first layer 11 to obtain a molded product corresponding to the second layer 12.

[0091] [Example 8]

[0092] Aluminum hydroxide having an average particle diameter of 5 to 50 μm was used as the second thermally conductive filler, and for 100 parts by mass of the second acrylic adhesive, 337.25 parts by mass of the second thermally conductive filler described above was compounded to prepare a second thermally conductive composition. An acrylic polymer was used as the second acrylic adhesive.

[0093] The second thermally conductive composition was applied to the first layer 11 to obtain a molded product corresponding to the second layer 12. The ASKER C hardness and the thermal conductivity were measured to obtain an ASKER C hardness of 64 and a thermal conductivity of 1.28 W / m-K.

[0094] [Comparative Example 5]

[0095] The second thermally conductive composition was prepared by blending 421.65 parts by mass of the second thermally conductive filler having an average particle diameter of 5 to 50 μm with respect to 100 parts by mass of the second acrylic adhesive. The acrylic polymer was used as the second acrylic adhesive.

[0096] The second thermally conductive composition was applied to the first layer 11 to obtain a molded product corresponding to the second layer 12. The ASKER C hardness and the thermal conductivity were measured to obtain an ASKER C hardness of 64 and a thermal conductivity of 1.28 W / m-K.

[0097] [Comparative Example 6]

[0098] The second thermally conductive composition was prepared by blending 137.19 parts by mass of the second thermally conductive filler having an average particle diameter of 5 to 50 μm with respect to 100 parts by mass of the second acrylic adhesive. The acrylic polymer was used as the second acrylic adhesive.

[0099] The second thermally conductive composition was applied to the first layer 11 to obtain a molded product corresponding to the second layer 12. The ASKER C hardness and the thermal conductivity were measured to obtain an ASKER C hardness of 64 and a thermal conductivity of 1.28 W / m-K.

[0100] (3) Other Embodiments

[0101] The above-described embodiments are merely illustrative of the present application, and the present application is not limited to the above-described embodiments. That is, the present application can be implemented in various forms without departing from the technical idea of the present application.

[0102] For example, in the above-described embodiments, specific examples of the constituent materials of the heat transfer member 1 of the present application were described, which were blended at specific blending ratios. However, the blending ratios of the constituent materials can be arbitrarily adjusted within the numerical ranges described in the present application.

[0103] Also, a plurality of functions realized by one of the components exemplified in the above-described embodiments can be realized by a plurality of components. One function realized by one of the components exemplified in the above-described embodiments can be realized by a plurality of components. A plurality of functions realized by a plurality of components exemplified in the above-described embodiments can be realized by one component. One function realized by a plurality of components exemplified in the above-described embodiments can be realized by one component. A part of the configuration exemplified in the above-described embodiments can be omitted. In the above-described embodiments, at least a part of the configuration exemplified in one of the embodiments can be added to or replaced with the configuration exemplified in the above-described embodiments other than the one of the embodiments.

[0104] (4) Supplement

[0105] Further, as is apparent from the above-described exemplary embodiments, the heat transfer member of the present application can additionally have the following listed configurations.

[0106] (A) The first acrylic-based adhesive can contain at least an acrylic polymer and a plasticizer. Also, in the first acrylic-based adhesive, 15 to 45 parts by mass of the plasticizer can be blended with respect to 100 parts by mass of the acrylic polymer in terms of mass ratio.

[0107] (B) The first thermally conductive filler can contain at least silicon carbide having an average particle diameter of 60 to 100 μm, first spherical alumina having an average particle diameter of 70 to 100 μm, second spherical alumina having an average particle diameter of 1 to 30 μm, and first magnesium hydroxide having an average particle diameter of 0.5 to 2 μm. The second thermally conductive filler can contain aluminum hydroxide having an average particle diameter of 5 to 50 μm as a necessary component, and can contain second magnesium hydroxide having an average particle diameter of 0.5 to 2 μm as an arbitrary component. In the first thermally conductive filler, 20 to 40 parts by mass of the silicon carbide, 20 to 50 parts by mass of the first spherical alumina, 20 to 50 parts by mass of the second spherical alumina, and 1 to 10 parts by mass of the first magnesium hydroxide can be blended in terms of mass ratio in 100 parts by mass of the first thermally conductive filler. In the second thermally conductive filler, 90 to 100 parts by mass of the aluminum hydroxide and 0 to 10 parts by mass of the second magnesium hydroxide can be blended in terms of mass ratio in 100 parts by mass of the second thermally conductive filler.

[0108] (C) The first layer can be configured so as to have ASKER C hardness of 0.1 to 22 and thermal conductivity of 2 to 15 W / m·K.

[0109] (D) The plurality of layers can include a third layer that is opposed to the second layer with the first layer interposed, and is in contact with the first layer on the side of the first layer facing away from the second layer and is laminated. The third layer can be configured of a resin film having a thickness of 1 to 15 μm.

Claims

1. A heat conducting member, characterized by, The heat conducting member is a laminate provided with a plurality of layers including a first layer and a second layer laminated at a position in contact with each other, The first layer is composed of a first heat conducting composition containing at least a first acrylic adhesive, a first heat conducting filler, and a dispersant. The second layer is composed of a second heat conducting composition containing at least a second acrylic adhesive and a second heat conducting filler. In the first heat conducting composition, 500 to 1200 parts by mass of the first heat conducting filler and 0.2 to 5 parts by mass of the dispersant are formulated with respect to 100 parts by mass of the first acrylic adhesive. In the second heat conducting composition, 200 to 400 parts by mass of the second heat conducting filler is formulated with respect to 100 parts by mass of the second acrylic adhesive. The dispersant contains a linear polyester having a weight average molecular weight of 1000 to 2500 and having a phosphoric acid at a terminal thereof, and the first heat conducting filler contains at least silicon carbide having an average particle diameter of 60 to 100 μm, first spherical alumina having an average particle diameter of 70 to 100 μm, second spherical alumina having an average particle diameter of 1 to 30 μm, and first magnesium hydroxide having an average particle diameter of 0.5 to 2 μm. In the first heat conducting filler, 20 to 40 parts by mass of the silicon carbide, 20 to 50 parts by mass of the first spherical alumina, 20 to 50 parts by mass of the second spherical alumina, and 1 to 10 parts by mass of the first magnesium hydroxide are formulated with respect to 100 parts by mass of the first heat conducting filler. In the second heat conducting filler, 90 to 100 parts by mass of aluminum hydroxide having an average particle diameter of 5 to 50 μm and 0 to 10 parts by mass of second magnesium hydroxide having an average particle diameter of 0.5 to 2 μm are formulated with respect to 100 parts by mass of the second heat conducting filler.

2. The heat conducting member according to claim 1, wherein The first acrylic adhesive contains at least an acrylic polymer and a plasticizer, and 15 to 45 parts by mass of the plasticizer is formulated with respect to 100 parts by mass of the acrylic polymer.

3. The heat conducting member according to claim 1, wherein The first layer is configured so as to have an ASKER C hardness of 0.1 to 22 and a thermal conductivity of 2 to 15 W / m·K.

4. The heat conducting member according to claim 1, wherein The plurality of layers include a third layer which is opposed to the second layer via the first layer and is laminated in contact with the first layer on a side of the first layer opposite to the second layer, and the third layer is composed of a resin film having a thickness of 1 to 15 μm.

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