JP2017025281A - Heat-conductive member, heat-conductive member laminated body and heat-conductive member molded body - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a heat-conductive member having anisotropy in heat-conductivity and also excellent in toughness.SOLUTION: Provided is a heat-conductive member, in which, in the plane view, provided that an optional direction is defined as an X direction, the direction orthogonal to the x direction is defined as a y direction, and the thickness direction of the heat-conductive member is defined as a z direction, the heat conductivity λx in the x direction, the heat conductivity λy in the y direction and the heat conductivity λz in the z direction satisfy min(λx,λy)/λz≥5, and also, at least in either direction of the x direction or the y direction, tensile fracture elongation measured in accordance with JISK 7161 is 10% or higher.SELECTED DRAWING: None

Description

  The present invention relates to a heat conductive member, and a heat conductive member laminate and a heat conductive member molded body using the heat conductive member.

  Conventionally, a metal plate having excellent thermal conductivity has been used for a housing of an electronic device such as a mobile phone or a personal computer. In recent years, as an alternative material for such a metal plate, a heat conductive sheet having excellent heat conductivity in both the surface direction and the thickness direction has attracted attention.

  For example, Patent Document 1 below discloses a heat conductive sheet including graphite, which is a graphene laminate, and a conductive material layer. According to Patent Document 1, a conductive material layer is intercalated between graphite graphenes, thereby improving thermal conductivity in the thickness direction as well as in the in-plane direction of graphene.

JP 2012-96937 A

  However, when a heat conductive sheet or a metal plate as in Patent Document 1 is used for a housing of an electronic device, the entire housing may become hot. For this reason, there are cases where the electronic device is difficult to carry or difficult to put on the knee or the like. Moreover, the heat conductive sheet of patent document 1 was brittle, and the moldability was not enough.

  An object of the present invention is to provide a heat conductive member having anisotropy in heat conductivity and excellent in toughness. Moreover, the other objective of this invention is to provide the heat conductive member laminated body and heat conductive member molded object which used the said heat conductive member.

  The heat conducting member according to the present invention is a heat conducting member, and in a plan view, an arbitrary direction is an x direction, a direction orthogonal to the x direction is a y direction, and a thickness direction of the heat conducting member is a z direction. The thermal conductivity λx in the x direction, the thermal conductivity λy in the y direction, and the thermal conductivity λz in the z direction satisfy min (λx, λy) / λz ≧ 5, and In at least one of the x direction and the y direction, the tensile elongation at break measured according to JIS K 7161 is 10% or more.

  In a specific aspect of the heat conducting member according to the present invention, the λx and the λy satisfy max (λx, λy) ≧ 2 W / (m · K).

  In another specific aspect of the heat conducting member according to the present invention, the λz satisfies λz ≦ 2W / (m · K).

  In another specific aspect of the heat conducting member according to the present invention, the bending stiffness measured in accordance with JIS K 7171 is at least 1 (N / mm) in at least one of the x direction and the y direction. It is. Here, the bending stiffness is a value obtained by dividing the magnitude of the inclination passing through the origin by the width of the sample in the load-displacement curve measured according to JIS K 7171.

  In still another specific aspect of the heat conducting member according to the present invention, the heat conducting member is made of a composite material including a synthetic resin and a carbon material having a graphene laminated structure.

  In still another specific aspect of the heat conducting member according to the present invention, the carbon material having the graphene laminated structure is graphite or exfoliated graphite.

  In still another specific aspect of the heat conducting member according to the present invention, the number of stacked graphene sheets of the carbon material having the graphene stacked structure is 1000 or more.

  In still another specific aspect of the heat conducting member according to the present invention, an average particle diameter of the carbon material having the graphene laminated structure is 0.1 μm or more and 100 μm or less.

  In still another specific aspect of the heat conducting member according to the present invention, the carbon material having the graphene laminated structure has a thickness of 300 nm or more.

  In still another specific aspect of the heat conducting member according to the present invention, the content of the carbon material having the graphene laminated structure is in the range of 50 parts by weight or more and 150 parts by weight or less with respect to 100 parts by weight of the synthetic resin. is there.

In still another specific aspect of the heat conducting member according to the present invention, the heat conducting sheet is provided. Preferably, the area of the sheet plane is 25 cm ² or more.

  The heat conductive member laminated body which concerns on this invention is equipped with the foamed resin layer and the heat conductive member comprised according to this invention laminated | stacked on the main surface of the at least one side of the said foamed resin layer.

  The heat conductive member molded body according to the present invention is a molded body of a heat conductive member or a heat conductive member laminated body configured according to the present invention.

  In still another specific aspect of the heat conducting member according to the present invention, the heat conducting member is used for a housing of an electronic device, an outdoor communication fixing device, or a smart meter.

  In still another specific aspect of the heat conducting member laminate according to the present invention, the heat conducting member laminate is used for a housing of an electronic device, an outdoor communication fixing device, or a smart meter.

  In still another specific aspect of the heat conductive member molded body according to the present invention, the heat conductive member molded body is used for a housing of an electronic device, an outdoor communication fixing device, or a smart meter.

  The heat conduction member according to the present invention has a heat conductivity λx in the x direction when an arbitrary direction is an x direction, a direction orthogonal to the x direction is a y direction, and a thickness direction is a z direction in plan view. The thermal conductivity λy in the y direction and the thermal conductivity λz in the z direction satisfy min (λx, λy) / λz ≧ 5, and in JIS K 7161 in at least one of the x direction and the y direction. The tensile elongation at break measured according to the criteria is 10% or more. Therefore, the heat conducting member according to the present invention has anisotropy in heat conductivity and is excellent in toughness.

It is typical sectional drawing which shows the heat conductive sheet laminated body as an example of the heat conductive member laminated body which concerns on this invention. (A) is a typical top view of the container-like upper and lower pair metal mold | die used for shaping | molding of the resin laminated board obtained by the Example and the comparative example, (b) is a model in alignment with the AA line. FIG.

  Details of the present invention will be described below.

(Heat conduction member)
In the heat conductive member according to the present invention, the heat conductivity λx in the x direction, the heat conductivity λy in the y direction, and the heat conductivity λz in the z direction satisfy min (λx, λy) / λz ≧ 5. Further, the tensile elongation at break in at least one of the x direction and the y direction is 10% or more.

  In the present specification, the x direction is an arbitrary direction in plan view. The y direction is a direction orthogonal to the x direction in plan view. The z direction is the thickness direction of the heat conducting member. Therefore, the z direction is a direction orthogonal to the x direction and the y direction.

  For example, when the heat conducting member is a heat conducting sheet, the x direction is an arbitrary direction on the sheet plane. The y direction is a direction orthogonal to the x direction on the sheet plane. The z direction is the thickness direction of the heat conductive sheet. Therefore, the z direction is a direction orthogonal to the x direction and the y direction.

  The thermal conductivity in each of the x direction, the y direction, and the z direction can be calculated using the following equation (1).

  Thermal conductivity (W / (m · K)) = thermal diffusivity × density × ratio (1)

  In Formula (1), the thermal diffusivity in each direction in the x direction, the y direction, and the z direction can be measured using, for example, a product name: Thermowave Analyzer, manufactured by Bethel.

  The min (λx, λy) means a value having a lower thermal conductivity among λx and λy. Therefore, min (λx, λy) / λz ≧ 5 means that the ratio of the lower thermal conductivity of λx and λy to λz is 5 or more.

  The tensile elongation at break is a value measured according to JIS K 7161.

  Since the heat conducting member of the present invention has min (λx, λy) / λz ≧ 5, the thermal conductivity in the plane direction is higher than the thermal conductivity in the thickness direction, and the thermal conductivity is made anisotropic. Have. Moreover, since the tensile elongation at break in at least one of the x direction and the y direction is 10% or more, the toughness is high and the moldability is excellent.

  From the viewpoint of giving further anisotropy due to thermal conductivity, min (λx, λy) / λz ≧ 10 is preferable, and min (λx, λy) / λz ≧ 20 is more preferable. Note that the upper limit of min (λx, λy) is preferably as high as possible, but is preferably about 3000 because of the properties of the material.

  In the present invention, it is preferable that the λx and the λy satisfy max (λx, λy) ≧ 2 W / (m · K). The max (λx, λy) means a value having a higher thermal conductivity among λx and λy. Therefore, max (λx, λy) ≧ 2W / (m · K) means that the thermal conductivity having the higher thermal conductivity of λx and λy is 2 W / (m · K) or more. Yes.

  When max (λx, λy) is in the above range, the thermal conductivity in the surface direction can be further enhanced.

  The λz is preferably λz ≦ 2W / (m · K). When λz is within the above range, the thermal conductivity in the thickness direction is lowered, and it becomes possible to have more anisotropy due to the thermal conductivity.

  The tensile elongation at break is preferably 10% or more as measured in both the x direction and the y direction. In that case, the toughness of the heat conducting member can be further enhanced, and the moldability can be further enhanced. However, in the present invention, only the value in one direction out of the x direction and the y direction out of the tensile elongation at break may be 10% or more.

  From the viewpoint of further enhancing the toughness of the heat conducting member and further improving the moldability, the tensile breaking elongation of the heat conducting member is preferably 15% or more, and more preferably 20% or more. From the viewpoint of securing rigidity, the upper limit value of the tensile breaking elongation of the heat conducting member is preferably about 40%.

The heat conduction member preferably has a bending rigidity in a range of 1 (N / mm) or more in at least one of the x direction and the y direction. The above bending stiffness is JIS
The value measured according to K7171. More specifically, the bending rigidity is a value obtained by dividing the magnitude of the inclination passing through the origin by the width of the sample in the load-displacement curve measured according to JIS K 7171.

The shape of the heat conducting member of the present invention is not particularly limited. The shape of the heat conductive member of the present invention may be a sheet shape, that is, a heat conductive sheet, or may be various shapes formed by injection molding. In the case of a heat conductive sheet, the area of the sheet plane is preferably 25 cm ² or more. In this case, it can be used more suitably as a housing for an electronic device, an outdoor communication fixing device or a smart meter. In addition, the area of the said sheet plane shall mean the area of the main surface of at least one side among the two main surfaces which are mutually opposing of a heat conductive sheet.

  The heat conducting member of the present invention is preferably composed of a composite material including a carbon material having a graphene laminated structure and a synthetic resin. In this case, a further anisotropy can be given due to thermal conductivity. Moreover, the toughness of the heat conducting member can be further enhanced, and the moldability can be further enhanced. In the present invention, the thermal conductivity and the tensile elongation at break in each direction can be appropriately adjusted by changing the type of carbon material having a graphene laminated structure, the blending ratio, and the like.

  The synthetic resin is not particularly limited, and various known synthetic resins can be used. Preferably, a thermoplastic resin is used as the synthetic resin. When a thermoplastic resin is used, the moldability of the heat conducting member can be further enhanced.

  The thermoplastic resin is not particularly limited. For example, polyethylenes such as high-density polyethylene, low-density polyethylene, and linear low-density polyethylene, polypropylenes such as homopolypropylene, block polypropylene, and random polypropylene, norbornene resin, and the like Cyclic polyolefins, polyvinyl acetates such as polyvinyl acetate and ethylene vinyl acetate, polyvinyl acetate derivatives such as polyvinyl alcohol and polyvinyl butyral, polyesters such as PET, polycarbonate and polylactic acid, polyethylene oxide, polyphenylene ether , Polyether resins such as polyetheretherketone, acrylic resins such as PMMA, sulfones such as polysulfone and polyethersulfone, fluorine such as PTFE and PVDF Resins, polyamide resins such as nylon, polyvinyl chloride, halogenated resins such as vinylidene chloride, polystyrene, polyacrylonitrile or a copolymer resin thereof such and the like. These may be used alone or in combination. Preferably, it is desirable to use a polyolefin that is inexpensive and easy to mold under heating.

  Although it does not specifically limit as a carbon material which has the said graphene laminated structure, Graphite, a carbon nanotube, exfoliated graphite, a graphene, etc. can be used. These may be used alone or in combination. The exfoliated graphite is obtained by exfoliating the original graphite and refers to a graphene sheet laminate that is thinner than the original graphite. The number of graphene sheets laminated in exfoliated graphite should be less than the original graphite.

  In the carbon material having the above graphene stacked structure, the number of graphene sheets stacked is preferably 1000 layers or more, more preferably 1500 layers or more, and further preferably 2000 layers or more.

  Note that the number of graphene sheets stacked in graphite can be obtained by measuring the thickness of graphite using a scanning electron microscope (SEM) and dividing by the thickness of the graphene sheet 0.33 nm / layer.

  The number of laminated graphene sheets of exfoliated graphite can be measured using a transmission electron microscope (TEM), and is an arithmetic average of the number of laminated exfoliated graphites. When the number of stacked layers is equal to or more than the above lower limit, the cost of the carbon material having a graphene structure can be suppressed. On the other hand, from the viewpoint of the rigidity reinforcing effect as a filler, the upper limit of the number of graphene sheets stacked is about 3500 layers.

  The average particle size of the carbon material having the graphene laminated structure is preferably 0.1 μm or more and 100 μm or less. The said average particle diameter means the largest outer dimension of a surface direction. The average particle diameter can be measured using, for example, a laser diffraction particle size distribution measuring apparatus. When the average particle diameter of the carbon material is within the above range, the tensile breaking elongation of the heat conducting member can be further increased.

  The thickness of the carbon material having the graphene stacked structure is preferably 300 nm or more, more preferably 500 nm or more, and further preferably 660 nm or more. When the thickness of the carbon material is not less than the above lower limit, the cost of the carbon material having a graphene structure can be suppressed. On the other hand, from the viewpoint of the rigidity reinforcing effect as the filler, the upper limit of the thickness of the carbon material is about 1200 nm.

  The content of the carbon material having the graphene laminated structure is preferably in the range of 50 to 150 parts by weight with respect to 100 parts by weight of the synthetic resin. When there is too little content of the said carbon material, the heat conductivity in the surface direction of a heat conductive member may not fully be improved. When there is too much content of the said carbon material, a heat conductive member will become weak and a moldability may worsen.

  The carbon material is preferably dispersed in the synthetic resin. When the said carbon material is disperse | distributed in a synthetic resin, the heat conductivity in the surface direction of a heat conductive member can be improved further.

  The method for dispersing the carbon material in the synthetic resin is not particularly limited, but the carbon material can be dispersed by kneading the synthetic resin and the carbon material.

  The kneading method is not particularly limited. For example, a kneading method under heating using a kneading device such as a twin screw kneader such as a plast mill, a single screw extruder, a twin screw extruder, a Banbury mixer, or a roll. Etc. Among these, the method of melt kneading using an extruder is preferable.

  In the composite material, various additives may be added as optional components. Additives include, for example, antioxidants such as phenols, phosphoruss, amines, and sulfurs; ultraviolet absorbers such as benzotriazoles and hydroxyphenyltriazines; metal hazard inhibitors; hexabromobiphenyl ether, decabromo Halogenated flame retardants such as diphenyl ether; flame retardants such as ammonium polyphosphate and trimethyl phosphate; various fillers; antistatic agents; stabilizers; These may be used alone or in combination.

  The manufacturing method of the heat conductive member of this invention is not specifically limited. For example, a composite material including a synthetic resin and a carbon material having a graphene laminated structure can be obtained by forming a sheet by pressing, extruding, calendering, or the like. Moreover, it is good also as a desired shape by injection molding. In that case, the thermal conductivity in each direction and the tensile elongation at break can be appropriately adjusted by changing the type of carbon material having a graphene laminated structure, the blending ratio, and the like.

  As described above, the heat conducting member according to the present invention has a low thermal conductivity in the thickness direction, and therefore, when used in a casing of an electronic device such as a mobile phone or a personal computer, the sheet surface side that touches the human body is hot. Hard to become. Moreover, since the thermal conductivity is excellent in the surface direction, heat can be sufficiently radiated in the surface direction. For this reason, it is difficult to cause a problem that the electronic device becomes hot and difficult to hold or difficult to put on the knee or the like. Therefore, the heat conducting member of the present invention can be used for a casing of an electronic device such as a mobile phone or a personal computer.

  Moreover, the heat conductive member comprised with the said composite material has improved rust resistance, a weather resistance, and rigidity. Therefore, when the heat conducting member is made of the above composite material, it can be suitably used for an outdoor communication fixing device or a smart meter housing.

  When used in a housing such as an outdoor communication fixing device or a smart meter, electromagnetic wave transmission may be required. Such electromagnetic wave permeability can be adjusted by the amount of carbon material having a graphene structure and the degree of peeling.

  The heat conductive member of the present invention has low heat conductivity in the thickness direction and has high rigidity, and therefore can be used as a heat insulating material. Building materials such as roofs, walls, ceilings, floors or doors; tables It can be used for furniture materials such as chairs or partitions; interior materials and exterior materials for ships, airplanes, railways, and automobiles.

  Moreover, the elasticity modulus of a heat conductive member can also be adjusted according to a use. The elastic modulus can be adjusted by changing the type of carbon material having a graphene structure and the blending ratio.

  Thus, in the heat conductive member of this invention, a physical property can be adjusted suitably according to the intended use.

(Heat conduction member laminate)
Hereinafter, the heat conductive member laminate of the present invention will be described with reference to the drawings. FIG. 1 is a schematic cross-sectional view showing a heat conductive sheet laminate as an example of a heat conductive member laminate according to the present invention. As shown in FIG. 1, the heat conductive sheet laminate 1 includes first and second heat conductive sheets 2 and 3 and a foamed resin layer 4.

  The foamed resin layer 4 includes a first main surface 4a and a second main surface 4b facing the first main surface 4a. On the first main surface 4 a of the foamed resin layer 4, the first heat conductive sheet 2 is provided. On the other hand, the second heat conductive sheet 3 is provided on the second main surface 4 b of the foamed resin layer 4. Therefore, the foamed resin layer 4 is provided so as to be sandwiched between the first and second heat conductive sheets 2 and 3. The heat conductive sheet laminate 1 is a heat conductive sheet laminate having a three-layer structure in which first and second heat conductive sheets 2 and 3 are provided on both surfaces of a foamed resin layer 4. In addition, in this invention, the number of lamination | stacking of each layer which comprises the heat conductive sheet laminated body 1 is not specifically limited.

  The 1st, 2nd heat conductive sheets 2 and 3 are the heat conductive members of this invention mentioned above, respectively, and have a sheet-like shape.

  The foamed resin layer 4 is made of a thermoplastic resin. The foamed resin layer 4 has a plurality of bubble cells inside. The expansion ratio of the foamed resin layer 4 is preferably 3 cc / g or more and 30 cc / g or less. By setting the expansion ratio of the foamed resin layer within the above range, the heat conductive sheet laminate can be further reduced in weight and the moldability can be further enhanced.

  Although it does not specifically limit as a material which comprises the said foamed resin layer, It is preferable that it is a thermoplastic resin. The thermoplastic resin is preferably a polyolefin. Examples of the polyolefin include polyethylene which is an ethylene homopolymer, ethylene-α-olefin copolymer, ethylene- (meth) acrylic acid copolymer, ethylene- (meth) acrylic acid ester copolymer, ethylene-vinyl acetate copolymer. Polyethylene resins such as polymers, polypropylene as propylene homopolymers, polypropylene resins such as propylene-α-olefin copolymers, butene homopolymers, homopolymers or copolymers of conjugated dienes such as butadiene and isoprene At least one selected from the group consisting of can be used. As the polyolefin, polyethylene or polypropylene is preferably used.

  Moreover, you may use various additives for the said foamed resin layer as an arbitrary component. Additives include, for example, antioxidants such as phenols, phosphoruss, amines, and sulfurs; ultraviolet absorbers such as benzotriazoles and hydroxyphenyltriazines; metal hazard inhibitors; hexabromobiphenyl ether, decabromo Halogenated flame retardants such as diphenyl ether; flame retardants such as ammonium polyphosphate and trimethyl phosphate; various fillers; antistatic agents; stabilizers; These may be used alone or in combination.

  The foamed resin layer can be formed by molding a commercially available foamed resin sheet. But you may produce by extruding foamable resin, and a manufacturing method is not specifically limited. Moreover, you may produce the said foamed resin layer by shape | molding two or more foamed resin sheets.

  It does not specifically limit about the manufacturing method of the said heat conductive sheet laminated body. For example, first, a laminate is produced by extruding and laminating a material constituting the heat conductive sheet on the surface of the foamed resin sheet. Subsequently, two sheets of the obtained laminated plate are laminated so that the foamed resin layer surfaces overlap each other, and heat-pressed to laminate the second thermal conductive sheet, the foamed resin layer, and the first thermal conductive sheet in this order. The heat conductive sheet laminated body made can be obtained.

  In the above embodiment, a three-layered laminate using a heat conductive sheet as the heat conductive member is used. However, the heat of the present invention laminated on at least one main surface of the foamed resin layer and the foamed resin layer. As long as the conductive member is provided, the number of stacked layers is not particularly limited.

(Heat conduction member molding)
The heat conductive member molded body of the present invention is obtained by molding the above-described heat conductive member or heat conductive member laminate of the present invention. That is, the heat conductive member molded body of the present invention is a molded body of the heat conductive member or the heat conductive member laminated body of the present invention described above.

  The heat conducting member or the heat conducting member laminate can be formed by, for example, pressing, extrusion, extrusion laminating, or the like.

  As described above, the heat conductive member of the present invention is used in the heat conductive member laminate and the heat conductive member molded body of the present invention. Therefore, the heat conductive member laminate and the heat conductive member molded body of the present invention can be suitably used for a housing such as an electronic device, an outdoor communication fixing device, or a smart meter.

  Moreover, since the heat conductive member laminate and the heat conductive member molded body of the present invention have low thermal conductivity in the thickness direction and have increased rigidity, they can be used as heat insulating materials such as roofs, walls, It can be used for building materials such as ceilings, floors or doors; furniture materials such as tables, chairs or partitions; interior materials and exterior materials such as ships, airplanes, railways and automobiles.

  Hereinafter, the effects of the present invention will be clarified by giving specific examples and comparative examples of the present invention. In addition, this invention is not limited to a following example.

Example 1
95 parts by weight of polypropylene (PP, product name “E-150GK” manufactured by Prime Polymer Co., Ltd.) and 5 parts by weight of styrene-ethylene-butadiene-styrene copolymer (SEBS, product name “H1062” manufactured by Asahi Kasei Chemicals) , 100 parts by weight of graphite A (product name “CNP7”, manufactured by Ito Graphite Co., Ltd., number of layers 1300, average particle size 7 μm, thickness 420 nm) is used with a lab plast mill (product number “R100” manufactured by Toyo Seiki Co., Ltd.). Then, a composite material was obtained by melt-kneading at 200 ° C. The obtained composite material was molded into a sheet by press working under conditions of a temperature of 200 ° C., a pressure of 20 MPa, and a time of 5 minutes to obtain a heat conductive sheet having a thickness of 1 mm as a heat conductive member.

(Example 2)
Except for using exfoliated graphite (manufactured by xGScience, trade name “xGnPM-5”, number of layers 180 layers, average particle size 5 μm, thickness 60 nm) instead of graphite A, the same as in Example 1, A heat conductive sheet having a thickness of 1 mm as a heat conductive member was obtained.

(Example 3)
In the composition of Example 1, a master batch was prepared using an extruder (manufactured by Ikegai Co., Ltd., model number “PCM30”). The produced master batch was molded at 200 ° C. with an injection molding machine (manufactured by Toshiba Machine Co., Ltd., model number “IS30EPN”) to obtain a 1 mm thick sheet-shaped heat conductive sheet as a heat conductive member.

Example 4
In the composition of Example 2, a master batch was prepared using an extruder (manufactured by Ikegai Co., Ltd., model number “PCM30”). The produced master batch was molded at 200 ° C. with an injection molding machine (manufactured by Toshiba Machine Co., Ltd., model number “IS30EPN”) to obtain a heat conduction sheet having a thickness of 1 mm as a heat conduction member.

(Comparative Example 1)
Instead of the polypropylene and the styrene-ethylene-butadiene-styrene copolymer (SEBS) of Example 1, polypropylene (PP, product name “E-150GK” manufactured by Prime Polymer Co., Ltd.) was used alone, and graphite A 1 mm in thickness in the same manner as in Example 1 except that graphite B (trade name “SG-BH8”, 15000 layers, average particle size 8 μm, thickness 5000 nm) manufactured by Ito Graphite Co., Ltd. was used instead of A heat conductive sheet was obtained.

(Comparative Example 2)
A commercially available graphite sheet (manufactured by Panasonic Corporation, trade name “EYGS121807”) having a thickness of 70 μm was used as the heat conductive sheet.

(Comparative Example 3)
A heat conductive sheet having a thickness of 1 mm was obtained by molding ABS (manufactured by Nippon A & L Co., Ltd., Clastic) at 200 ° C. with an injection molding machine.

(Evaluation)
The following evaluation was performed about the heat conductive sheet obtained in Examples 1-4 and Comparative Examples 1-3. The results are shown in Table 1 below.

Thermal conductivity;
About the heat conductive sheet of an Example and a comparative example, the heat conductivity ((lambda) x, (lambda) y, and (lambda) z) in ax direction, y direction, and z direction was calculated | required using the following formula | equation, respectively.

  The thermal conductivity in each direction can be calculated using the following formula (1).

  Thermal conductivity (W / (m · K)) = thermal diffusivity × density × ratio (1)

  In Formula (1), the thermal diffusivity of each direction was measured using the product name: Thermowave Analyzer, manufactured by Bethel.

  Using λx, λy, and λz obtained as described above, min (λx, λy) / λz, max (λx, λy), and λz were obtained.

Tensile elongation at break;
The tensile elongation at break was performed according to the tensile test of JIS K 7161 in the direction of max (λx, λy).

Bending stiffness;
In accordance with JIS K 7171, the measurement was performed in the direction of max (λx, λy) at a test speed of 50 mm / min and a span distance of 100 mm, and bending stiffness was calculated.

  The results are shown in Table 1 below.

(Example 5)
Two heat conductive sheets (first and second sheets) prepared in the same manner as in Example 1 are formed on both sides of a PP-based foam (trade name “Softlon SP” manufactured by Sekisui Chemical Co., Ltd.) constituting the foamed resin layer. A heat conductive sheet laminate having a thickness of 6 mm as a heat conductive member laminate was obtained by laminating and heat-pressing the heat conductive sheet.

(Example 6)
Two heat conductive sheets (first and second sheets) prepared in the same manner as in Example 2 are formed on both sides of a PP-based foam (trade name “Softlon SP” manufactured by Sekisui Chemical Co., Ltd.) constituting the foamed resin layer. A heat conductive sheet laminate having a thickness of 6 mm as a heat conductive member laminate was obtained by laminating and heat-pressing the heat conductive sheet.

(Comparative Example 4)
Two heat conductive sheets (first and second sheets) prepared in the same manner as in Comparative Example 1 are formed on both sides of a PP-based foam (trade name “Softlon SP” manufactured by Sekisui Chemical Co., Ltd.) constituting the foamed resin layer. A heat conductive sheet laminate having a thickness of 6 mm was obtained by laminating and heat-pressing the heat conductive sheet.

(Comparative Example 5)
Two heat conductive sheets of Comparative Example 2 (first and second heat conductive sheets) are formed on both sides of a PP foam (made by Sekisui Chemical Co., Ltd., trade name “Softlon SP”) constituting the foamed resin layer. Were laminated and hot pressed to obtain a heat conductive sheet laminate having a thickness of 6 mm.

(Evaluation)
The following evaluation was performed about the heat conductive sheet laminated body obtained in Examples 5 and 6 and Comparative Examples 4 and 5. The results are shown in Table 2 below.

Sheet top surface temperature;
A heater of 25 mm × 25 mm was attached to the center portion of a 170 mm × 170 mm sheet-shaped sample via grease, and the heater mounting portion was placed on the lower side and kept in a horizontal state. The voltage of the heater was adjusted to 105 ° C., the temperature on the surface opposite to the heater mounting surface was observed by thermography, and the temperature of the sheet upper surface after 15 minutes was measured as “sheet upper surface temperature”. The results are shown in Table 2 below. In Table 2, the evaluation symbols are as follows.

◎ ・ ・ ・ Sheet upper surface temperature is less than 40 ℃ ○ ・ ・ ・ Sheet upper surface temperature is 40 ℃ or more and less than 60 ℃ × ・ ・ ・ Sheet upper surface temperature is 60 ℃ or more

Moldability;
About the obtained heat conductive sheet laminated body, the test piece of length 320mm x width 320mm was cut out. Subsequently, this test piece was fixed to a single molding machine (manufactured by Sanko Kiko Co., Ltd., product number: SPF-00001) and heated until the surface temperature of the test piece reached 170 ° C. After heating, it was taken out from the single molding machine and press-molded using a pair of upper and lower container molds shown in FIGS. 2 (a) and (b). 2A is a schematic plan view showing a container-like upper and lower pair mold, and FIG. 2B is a schematic cross-sectional view taken along the line AA.

  Next, the appearance quality (moldability) of the test piece (molded product) after molding was evaluated. The results are shown in Table 2 below. In Table 2, the evaluation symbols are as follows.

  In addition, on the outer surface (convex surface) of the molded product, the area of the portion where wrinkles (length 2 mm or more), unevenness (height difference 0.1 mm or more), gloss unevenness, and tearing occurred was defined as a defective area.

◎ ・ ・ ・ Defect area is less than 10% of total area ○ ・ ・ ・ Defect area is 10% or more and less than 20% of total area × ・ ・ ・ Defect area is 20% or more of entire area

DESCRIPTION OF SYMBOLS 1 ... Heat conductive sheet laminated body 2 ... 1st heat conductive sheet 3 ... 2nd heat conductive sheet 4 ... Foamed resin layer 4a ... 1st main surface 4b ... 2nd main surface

Claims (17)

A heat conducting member,
In a plan view, when an arbitrary direction is an x direction, a direction orthogonal to the x direction is a y direction, and a thickness direction of the heat conducting member is a z direction,
The thermal conductivity λx in the x direction, the thermal conductivity λy in the y direction, and the thermal conductivity λz in the z direction satisfy min (λx, λy) / λz ≧ 5, and
The heat conductive member whose tensile fracture | rupture elongation measured based on JISK7161 is 10% or more in at least one direction among the said x direction and the said y direction.   The heat conducting member according to claim 1, wherein the λx and the λy satisfy max (λx, λy) ≧ 2 W / (m · K).   The heat conducting member according to claim 1, wherein the λz satisfies λz ≦ 2 W / (m · K).   The bending rigidity measured in accordance with JIS K 7171 in at least one of the x direction and the y direction is 1 (N / mm) or more. Heat conduction member.   The heat conductive member according to any one of claims 1 to 4, wherein the heat conductive member is made of a composite material including a synthetic resin and a carbon material having a graphene laminated structure.   The heat conductive member according to claim 5, wherein the carbon material having the graphene laminated structure is graphite or exfoliated graphite.   The heat conductive member according to claim 5 or 6, wherein the number of laminated graphene sheets of carbon material having the graphene laminated structure is 1000 or more.   The heat conductive member according to claim 5, wherein an average particle diameter of the carbon material having the graphene laminated structure is 0.1 μm or more and 100 μm or less.   The heat conductive member according to any one of claims 5 to 8, wherein a thickness of the carbon material having the graphene laminated structure is 300 nm or more.   The heat according to any one of claims 5 to 9, wherein the content of the carbon material having the graphene laminated structure is in a range of 50 parts by weight or more and 150 parts by weight or less with respect to 100 parts by weight of the synthetic resin. Conductive member.   The heat conductive member according to any one of claims 1 to 10, which is a heat conductive sheet. The heat conductive member according to claim 11, wherein the area of the sheet plane is 25 cm ² or more.   A heat conductive member laminate comprising: a foamed resin layer; and the heat conductive member according to any one of claims 1 to 12, which is laminated on at least one main surface of the foamed resin layer.   The heat conductive member molded object which is a molded object of the heat conductive member of any one of Claims 1-12, or the heat conductive member laminated body of Claim 13.   The heat conductive member according to any one of claims 1 to 12, which is used for a housing of an electronic device, an outdoor communication fixing device or a smart meter.   The heat conductive member laminated body of Claim 13 used for the housing | casing of an electronic device, the fixing device for outdoor communication, or a smart meter.   The heat conductive member molded body according to claim 14, which is used for a housing of an electronic device, an outdoor communication fixing device or a smart meter.

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