JP2013080916A - Sheet and manufacturing method of the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sheet which does not cause degradation of flexibility or impair insulation properties in exchange for improving heat radiation performance, and also to provide a manufacturing method of the sheet.SOLUTION: A sheet 1 is fabricated by laminating film sheets 8 which is obtained by forming a film made of a resin material containing heat-dissipating filler. Before being laminated, each of the film sheets 8 has dot-like patterns printed on its one face in a scattered manner. The dot-like patterns are printed by using paste ink containing the heat-dissipating filler. The plurality of film sheets 8 are laminated and vacuum-pressed so that the sheet 1 (a substrate 80), in its completed state, includes multiple stages of wafer parts 10 laminated in the inside, but since thin-film parts 8a of the resin material are interposed between layers of the wafer parts 10, heat radiation performance in the thickness direction can be improved without impairing flexibility or insulation properties.

Description

  The present invention relates to a sheet that promotes heat dissipation from a heating element, and a method for manufacturing the sheet.

  Conventionally, heat dissipation sheets are known in which heat dissipation is improved by filling a soft resin such as a silicone resin or an elastomer with a filler such as metal, metal oxide, or carbon fiber (see, for example, Patent Documents 1 and 2). .) Although the heat conductivity of the resin itself is low, the heat dissipation of the soft resin can be enhanced by mixing a filler with a high heat conductivity. The flexibility of the heat-dissipating sheet is necessary to ensure the adhesion to the package surface and heat sink of electronic devices, etc. it can.

  In addition, it is more efficient that the heat-dissipating sheet has a certain anisotropy than heat can be transmitted uniformly in all directions. For example, when the electronic device and the heat sink are interleaved as described above, the heat radiation performance in the thickness direction connecting the two is more important than the direction along the contact surface between the two.

  The anisotropy of the heat dissipation performance can be obtained by orienting the filler filled in the resin as desired. For the orientation of the filler, for example, a method in which a plurality of sheets in which the filler is oriented in the horizontal direction is laminated and cured, and then sliced in the lamination direction to obtain a vertical orientation film (Patent Documents 1 and 2) or Prior arts such as a method of obtaining vertical alignment by passing a rod-shaped magnetic filler through a magnetic field or an electric field (Patent Documents 3 and 4) are used.

Japanese Patent Laid-Open No. 2002-26202 Japanese Patent No. 3531785 JP 2009-266913 A JP 2008-218771 A

  In general, the thermal conductivity of a heat-dissipating sheet increases as more filler is added to the resin, but the hardness increases in proportion to the amount added, and the flexibility required to obtain adhesion to the heating element and heat sink. Is damaged. When flexibility is impaired, air easily enters between the heating element and the heat sink, and a heat insulating space is created there, thereby deteriorating heat dissipation performance. For this reason, too much pursuing improvement in the thermal diffusivity of the heat-dissipating sheet is a tipping over to add too much filler.

  In general, a filler having a high thermal conductivity is a conductive material such as metal or carbon. If a large amount of these fillers is blended, the insulating property is impaired no matter how much resin is used. In view of the fact that most of the use objects of the heat radiating sheet are electrically sensitive electronic components, it is not preferable that there is anxiety about insulation even if it is a little.

  Furthermore, regarding the anisotropy of heat dissipation performance (thermal conductivity), the filler itself needs to have anisotropy in the thermal conductivity in order to increase the thermal conductivity in the thickness direction by the orientation of the filler as in the prior art. And the types of such fillers are limited to some extent (eg, graphite, carbon fiber, boron nitride, etc.). In addition to adding fillers to the resin, it is necessary to perform special processing to orient them, which increases the manufacturing cost.

  Therefore, the present invention provides a sheet that can obtain desired anisotropy for heat conduction without reducing flexibility or impairing insulation in exchange for improving heat dissipation performance, and a method for manufacturing the same. is there.

In order to solve the above problems, the present invention employs the following solutions.
First, the present invention provides a sheet. The sheet has a sea-island structure in which a resin having a thickness is used as a sea component and a plurality of wafer portions containing a heat dissipating filler are used as island components. Wafer portions serving as island components are scattered in a direction perpendicular to the thickness direction within the resin, and a plurality of wafer portions are arranged side by side on the same line as viewed in the resin thickness direction at each position on the island. The individual wafer portions are spaced apart from each other within the resin.

  According to the sheet of the present invention, due to the plurality of wafer portions arranged on the same line at each position of the island, a plurality of passages of heat in the thickness direction are formed inside the resin. That is, at each position of the island, a plurality of wafer portions are stacked in multiple stages, and a heat dissipation material having a higher thermal conductivity than that of the resin is used for the wafer portions. As a result, the resin has a densely packed portion with high thermal conductivity in the thickness direction at each position of the island, so that the thermal conductivity in the thickness direction is improved at each position on the island, and these gather together. Thus, anisotropy of good heat dissipation performance can be brought about on the entire sheet.

  Each position of the island has a structure in which a thin film portion of the resin is interposed between the wafer portions as viewed in the thickness direction of the resin, and each wafer portion is independent in the thickness direction. In addition, since all the wafer portions are inside the resin, the wafer portions are not exposed on both surfaces facing each other in the thickness direction. Since the relationship between the wafer part and the resin is a sea-island structure with respect to the direction orthogonal to the thickness direction, the individual wafer parts are also independent in the direction orthogonal to the resin thickness direction. For this reason, the inside of the resin is insulated without being in contact with all three axes, so even if the heat dissipating filler has a certain conductivity, the insulation as a whole sheet is impaired. It will never be.

  The resin may contain a heat dissipating filler. By containing the heat dissipating filler, the resin can have thermal conductivity corresponding to the content (content ratio) of the heat dissipating filler. Moreover, about a wafer part, heat conductivity can be made high compared with the part of resin by making the content rate of a thermal radiation filler higher than resin.

The wafer portions may be regularly arranged at regular intervals when viewed in a direction orthogonal to the resin thickness direction.
In this case, the uneven heat dissipation performance due to the uneven density of the wafer portion can be prevented, and the heat dissipation performance of the entire sheet can be made uniform.

  Secondly, the present invention provides a sheet manufacturing method. The manufacturing method of a sheet | seat has the following processes.

[Film forming process]
In this step, a film sheet is formed by forming a resin material (one that does not contain a heat dissipating filler) or a resin material containing a heat dissipating filler. The film sheet formed here becomes a resin material of a base material forming a sheet shape.

[Printing process]
In this step, a dot-shaped pattern distributed on one surface of the film sheet is printed using a heat conductive ink containing a heat dissipating filler. Each dot-like pattern printed here becomes the wafer part (heat dissipation material).

[Molding process]
In this process, a plurality of film sheets with patterns obtained in the previous printing process are laminated in a state where each pattern overlaps in the thickness direction, and the film sheet obtained in the film forming process is laminated on the uppermost layer. Mold the sheet.

  According to the manufacturing method of the present invention, a sheet having high heat dissipation performance can be easily obtained by simple operations such as film sheet formation, pattern printing, and lamination. In particular, since a portion having high thermal conductivity can be formed by printing on a film sheet, there is no need to bother processing that is necessary for the orientation of the filler.

  Since the pattern part with high thermal conductivity is distributed and printed on one surface of the film sheet, the patterns can be reliably separated on each film sheet. Further, since the pattern portions are laminated in the thickness direction while being sandwiched between the film sheets of the resin material, the independence of the patterns in the thickness direction can be reliably maintained.

In the above printing step, a dot-like pattern regularly arranged at regular intervals can be printed on one surface of the film sheet.
Thereby, the unevenness of the heat dissipation performance due to the uneven distribution density of the dot pattern can be prevented, and the heat dissipation performance of the entire sheet can be made uniform.

  According to the sheet of the present invention, desired heat radiation performance can be exhibited while ensuring sufficient flexibility and insulation.

  Moreover, according to the manufacturing method of the present invention, a sheet excellent in flexibility, insulation and heat dissipation can be obtained without requiring complicated processing.

It is sectional drawing which showed the usage example of the sheet | seat. It is a longitudinal cross-sectional view which shows the structure of a sheet | seat in detail. It is the disassembled perspective view which showed the structure of the sheet | seat three-dimensionally. It is a top view which shows the film sheet of the state in which the dot-like pattern was printed on the whole surface. It is the elements on larger scale which show the form of the printed dot (wafer part). It is a continuous figure which shows the procedure included in a formation process. It is a table | surface which compares and shows the thermal diffusivity and volume resistivity of the sheet | seat of an Example, and the sheet | seat used as the comparative example. It is a table | surface which shows the volume resistivity of a general insulating material. It is a table | surface which shows the volume resistivity of the electrically-conductive material which contained the heat dissipation filler and gave electroconductivity.

  Hereinafter, embodiments of the present invention will be described. First, the structure of the sheet according to the embodiment will be described.

  FIG. 1 is a cross-sectional view showing a usage example of the sheet 1 in the present embodiment. In this usage example, the sheet 1 is used as a heat radiating member (heat radiating sheet). In addition, the solid line arrow shown in FIG. 1 has shown the heat transfer direction.

  The sheet 1 can be used for heat dissipation of the electronic component 4 or the like, for example. The electronic component 4 is mounted on a substrate 2 installed in an electronic device such as a PC (personal computer). Examples of the electronic component 4 include an IC chip and an LSI. The electronic component 4 has a structure in which an unillustrated integrated circuit is sealed with a package resin.

  The sheet 1 is installed on the upper surface (package upper surface) of the electronic component 4, and the heat sink 6 is installed on the upper surface. In this state, the sheet 1 is in close contact with the electronic component 4 and the heat sink 6 without any gaps. In addition, the electronic component 4 and the sheet | seat 1 may be adhere | attached with the adhesive agent, for example. Further, the heat sink 6 is strongly bonded to the electronic component 4 using, for example, a fastener (not shown). In FIG. 1, hatching is not shown in the cross section of the heat sink 6.

  Heat generated from the electronic component 4 serving as a heating element is transmitted to the heat sink 6 via the sheet 1. At this time, the lower surface of the sheet 1 that is in close contact with the electronic component 4 becomes an endothermic surface, and absorbs heat from the endothermic surface. In addition, the sheet 1 has a heat radiating surface on the top surface that is in close contact with the heat sink 6, and heat is released from the heat radiating surface to the heat sink 6. An air flow is formed around the heat sink 6 by, for example, a cooling fan (not shown), and heat reaching the heat sink 6 through the sheet 1 is taken away by the air flow.

[Sheet structure]
FIG. 2 is a longitudinal sectional view showing the structure of the sheet 1 in detail. 2 shows a part of the sheet 1 shown in FIG.

The sheet 1 is configured with a base material 80 (resin) having a sheet shape as a base, and the base material 80 has a structure in which, for example, film sheets 8 made of a plurality of resin materials are laminated. In this example, the film sheet 8 is stacked in five layers, but there is no particular limitation on the number of layers.
The resin material of the film sheet 8 is mixed with a heat-dissipating filler (not shown), so that the base material 80 has a certain degree of thermal conductivity.
The lower surface shown in FIG. 2 is a suction surface 80 a that is in close contact with the upper surface of the electronic component 4, and the upper surface is a heat dissipation surface 80 b that is in close contact with the lower surface of the heat sink 6.

[Wafer part]
A plurality of wafer portions 10 (all of which are not labeled in FIG. 2) are embedded in the substrate 80. Each wafer unit 10 is formed of a heat dissipation material having a higher content of heat dissipating filler than the resin material of the film sheet 8.

  The wafer portion 10 is laminated in multiple stages at intervals in the thickness direction of the base material 80, and a portion where the resin material of the film sheet 8 is partially thinned, that is, a thin film portion 8a is formed between the layers. ing. The thin film portion 8 a is formed between the wafer portions 10 inside the base material 80, and is also formed between the surface and the internal wafer portion 10 in the uppermost film sheet 8. In addition, the thin film part 8a is not formed in the film sheet 8 of the lowest layer.

  The wafer unit 10 is aligned along a virtual axis L drawn in the thickness direction of the substrate 80. That is, the wafer unit 10 is arranged in a plurality on the same line as viewed in the thickness direction of the base material 80 (resin). In FIG. 2, the axis line L is shown only at one place, but the row of the wafer portions 10 along the axis line L is formed by being scattered (distributed) in the direction along the heat absorbing surface 80 a of the base material 80. ing. The distribution of the wafer unit 10 will be further described later.

  On the axis L (thickness direction), the wafer portions 10 and the thin film portions 8a are alternately stacked inside the base material 80, so that the multi-stage wafer portions 10 are densely arranged in the thickness direction. It has become. As described above, the multi-stage wafer portions 10 are densely arranged, so that the heat radiation path 18 is formed along the axis L inside the base material 80 so as to be surrounded by the one-dot chain line in FIG. It is in.

  That is, the heat dissipation path 18 constitutes a path for heat extending in the thickness direction from the heat absorption surface 80a toward the heat dissipation surface 80b (a path through which heat is easily transmitted as a whole). In FIG. 2, only one heat radiation path 18 is shown with a dot-and-dash line and a sign, but the heat radiation paths 18 are distributed in the direction along the heat absorption surface 80 a of the substrate 80.

FIG. 3 is an exploded perspective view showing the structure of the sheet 1 in three dimensions. As described above, the base material 80 of the sheet 1 is formed by laminating a plurality of film sheets 8.
Each of the wafer portions 10 has a dot shape (regular hexagonal shape here), and the second to fifth film sheets 8 excluding the uppermost layer have a large number of wafer portions on one side. 10 are regularly scattered (distributed). For this reason, the sheet 1 has a sea-island structure in which the film sheet 8 (resin) is a sea component and a plurality of wafer portions 10 scattered therein are island components in terms of a direction orthogonal to the entire thickness direction. .

  Further, when the respective layers of the film sheet 8 are compared, the arrangement of the wafer portions 10 (aspects of the island positions) match each other. Thereby, in the state where the film sheets 8 are overlapped, the respective wafer portions 10 are correctly aligned on the axis L along the thickness direction of the base material 80 (resin) at each position of the island of the sea-island structure as described above. Will do. At this time, the individual wafer portions 10 are in a state of being separated (not in contact) with each other in the base material 80. Further, the regularly distributed wafer portions 10 can be suitably formed by printing a dot pattern on one surface of the film sheet 8 in advance, and details thereof will be described later together with the manufacturing method.

〔Production method〕
Next, a method for manufacturing the sheet 1 will be described. The sheet 1 of one embodiment can be manufactured through the following steps. The outline of each process is shown below.
[1] Film forming step: Film film 8 is formed.
[2] Printing process: A wafer pattern 10 is formed by printing a dot pattern on one surface of the film sheet 8.
[3] Molding step: A film sheet 8 with a pattern on which a dot-like pattern is printed is laminated, and a film sheet 8 on which no dot-like pattern is printed is laminated on the uppermost layer to mold the sheet 1.
Hereinafter, each process will be described in more detail.

[1] Film-forming process Although not particularly shown, in the film-forming process, first, a masterbatch is prepared with a resin (no heat-dissipating filler is kneaded), or the resin and heat-dissipating filler are kneaded to prepare a masterbatch. create.

  For the resin, for example, one or more materials selected from any one of the following groups can be used. When two or more resin materials are mixed, they are selected from the same group.

[Thermoplastic resin group]
For example, polyethylene, polypropylene, polystyrene, ABS resin, vinyl chloride resin, methyl methacrylate resin, nylon (registered trademark), fluorine resin, polycarbonate, polyester resin and the like.

[Thermosetting resin group]
For example, phenol resin, epoxy resin, melamine resin, urea resin, unsaturated polyester resin, alkyd resin, polyurethane, thermosetting polyimide and the like.

[Elastomer group]
For example, nitrile rubber, hydrogenated nitrile rubber, fluorine rubber, acrylic rubber, silicone rubber, urethane rubber, ethylene propylene rubber, chloroprene rubber, chlorosulfonated polyethylene, epichlorohydrin rubber, natural rubber, isoprene rubber, styrene butadiene rubber, butadiene rubber, many Sulfurized rubber, norbornene rubber and the like.

  In addition, it is not preferable to mix two or more resins selected from different groups in the same layer (film sheet 8). However, since the substrate 80 has a laminated structure, a different resin is appropriately used for each layer of the film sheet 8. It is possible to combine them. For example, one layer uses a thermoplastic resin and the other layer uses a thermosetting resin.

  The heat dissipating filler kneaded with the resin is made of, for example, alumina, aluminum nitride, boron nitride, magnesium oxide, magnesite, zinc oxide, carbon fiber, aluminum, silver, copper or the like. As the heat dissipating filler, a material obtained by processing these materials into a spherical shape, a needle shape, a scale shape or the like having a size of 1 to 100 μm, or a crushed material can be used.

  As a film forming method for the film sheet 8, for example, various methods such as a solution method, a calender method, and press molding can be used in addition to a melt extrusion method such as T-die film formation and inflation film formation.

[2] Printing process In the printing process, a dot-like pattern is printed on one surface of the film sheet 8 as described above.

[Ink used]
The ink used for printing is a paste ink in which a heat dissipating filler is contained in a resin (vehicle). The filler content of the paste ink is set higher than that of the film sheet 8. Thereby, compared with the resin material of the film sheet 8, the heat conductivity of the thermal radiation material which comprises the wafer part 10 can be made high.

  The filler content (rate) is preferably in the range of 50% to 95% by weight as the whole paste ink. This is because if it is less than 50% by weight, it is difficult to obtain the heat dissipation effect (heat dissipation performance) due to the inclusion of the heat dissipating filler, and if it exceeds 95% by weight, the flexibility of the completed sheet 1 is impaired. .

[Printing method]
As a printing method, methods such as screen printing, flexographic printing, and gravure printing can be used. The film thickness of the ink is, for example, in the range of 5 to 100 μm.

FIG. 4 is a plan view showing the film sheet 8 in a state where a dot-like pattern is printed on one side. The film sheet 8 shown in FIG. 4 is cut into an appropriate size.
Each wafer unit 10 viewed in the completed state of the sheet 1 is composed of dots printed on one surface of the film sheet 8. As described above, the dot pattern (pattern in which the wafer portions 10 are arranged) is a form in which hexagonal dots are regularly arranged two-dimensionally. Here, hexagonal dots are taken as an example, but other polygonal or round dots, star polygonal shapes, cross-shaped dots or the like may be printed. The dot arrangement may be a square arrangement in a matrix.

  FIG. 5 is a partially enlarged view showing the form of printed dots (wafer unit 10). The printed dots (wafer unit 10) are separated from other adjacent dots (wafer unit 10) on one surface of the film sheet 8, and the dot interval L is, for example, about 1 mm. Moreover, the diagonal length D of a regular hexagon is about 1-3 mm, for example.

  In this way, the printed individual dots are arranged such that they are not in contact with other dots on one surface of the film sheet 8 at any of the upper, lower, left and right positions. This is because if one dot is in contact with another dot, the flexibility of the sheet 1 may be lost in the completed state, and it may be conductive by contact with the dot (wafer portion 10). It is because there is sex.

[3] Molding Process FIG. 6 is a continuous diagram showing the steps included in the molding process. The procedure will be described below.
6A and 6B: In the forming step, a film sheet 8 with a pattern on which a dot pattern is printed (for example, four layers from the bottom) is laminated, and the dot pattern is printed on the uppermost layer. A sheet 1 is formed by laminating film sheets 8 that are not yet formed. This is for further ensuring insulation by suppressing exposure of the printed pattern (wafer portion 10) in the completed state of the sheet 1.

  In addition, when the film sheets 8 of each layer are stacked, the print pattern of the wafer unit 10 is overlapped in the thickness direction (on the imaginary axis L shown in FIG. 2). This is because the heat dissipation path 18 in the vertical direction (thickness direction) is formed inside the base material 80 in the completed state as described above to improve heat dissipation in the thickness direction.

  In FIG. 6, (C): The laminated body obtained by the above procedure is integrated by applying pressure in the thickness direction. As a method for integrating the laminate, it is preferable to use, for example, a vacuum press method, a thermal lamination method, or the like. Thereby, in the direction along one surface of the film sheet 8, the resin material is thermally flown to fill the gaps between the print patterns. Further, in the thickness direction, the resin material sandwiched between the upper and lower wafer portions 10 is thinned by heat flow and becomes a thin film portion 8a in a completed state.

  According to the manufacturing method described above, a dot-like pattern is printed on one surface of the film sheet 8, and the film sheet 8 with a pattern (the uppermost layer has no pattern) is simply laminated and embedded in the substrate 80. The wafer part 10 in a state can be easily formed. Further, by applying pressure while applying heat in the molding process, the film sheet 8 between the wafer layers 10 can be thinned by heat flow in the thickness direction, and the thin film portion 8a seen in the completed state can be easily formed. Thereby, the heat radiation path 18 can be easily formed inside the base material 80, and the desired heat radiation performance can be exhibited in the completed sheet 1.

  In the printing process, by using a printing pattern in which adjacent dots do not overlap in advance, the entire periphery of the wafer layer 10 can be covered with a resin material in a completed state. Thus, the insulating property of the sheet 1 can be ensured without the wafer layer 10 coming into contact with the external electronic component 4 or the heat sink 6.

  Further, in the printing process, by using regularly arranged printing patterns, dots (wafer layer 10) can be evenly distributed and arranged on one surface of the film sheet 8. And if the sheet | seat 1 is completed through a lamination process and a formation process, the heat radiation path 18 distributed regularly in the direction along the heat absorption surface 80a of the base material 80 can be formed easily.

  And in the completion state of the sheet | seat 1, since the thermal radiation path 18 is regularly distributed within the base material 80, thermal conductivity as the whole sheet | seat 1 does not deviate extremely, and it is from the thermal absorption surface 80a to the thermal radiation surface 80b. The heat can be transmitted evenly toward.

  Further, the sheet 1 does not have a structure in which the entire film sheet 8 contains a heat dissipating filler in a larger amount than usual. It is a structure with improved conductivity. Thereby, the usefulness of this embodiment is high at the point which implement | achieved desired heat dissipation performance, without impairing the softness | flexibility required as the sheet | seat 1. FIG.

  Further, the sheet 1 can be easily applied to an adhesive depending on the application, or can be colored by adding a pigment to the resin of the film sheet 8, and can be easily developed for various applications.

  Next, specific examples will be given and the usefulness of the sheet 1 will be verified by comparison with comparative examples.

[Example 1]
In Example 1, each material used for film formation of the film sheet 8, the substance name, and the weight ratio according to material are shown below. The film sheet 8 was formed by kneading the following materials with a Banbury mixer and forming a film having a thickness of 150 μm by a calendar method.

Base resin: 40 parts by weight of Sanfuku Industry Co., Ltd. (HRLC-1) Heat-dissipating filler: 30 parts by weight of synthetic magnesite (manufactured by Kamishima Chemical Co., Ltd .: MSL) Product: MSS) 30 parts by weight

[Print dot pattern]
A dot-like pattern was printed on one surface of the formed film sheet 8 using a screen printing apparatus. The ink used for printing is Toyo Ink Co., Ltd. silver paste ink (RAFS039). The printing conditions are shown below.
Drying temperature: 80 ° C
Drying time: 30 minutes About the dot-shaped pattern printed on the film sheet 8, the ink film thickness, pattern shape, and area ratio are shown below.
Ink film thickness: 30 μm
Dot shape: Regular hexagon with a diagonal length of 3 mm Dot interval: 1 mm, closest packing area ratio: 84.2%

[Sheet molding]
In Example 1, ten film sheets 8 formed were laminated and heated and pressed to form a single sheet 1. At this time, the film sheet 8 with a printing pattern was used from the second layer to the tenth layer of the film sheet 8 excluding the uppermost layer, and the unprinted film sheet 8 was used as the uppermost layer. The thickness of the sheet 1 (base material 80) after the heat press was 1 mm.

[Comparative Example 1]
A film sheet 8 was formed using the same material as in Example 1, and only the film sheet 8 was laminated without printing a dot-like pattern, followed by press molding to obtain a sheet 1 of Comparative Example 1. The thickness of the sheet 1 of the comparative example is 1.0 mm.

[Example 2]
In Example 2, each material used for the production of the film sheet 8, the substance name, and the weight ratio for each material are shown below.

Base resin: 72 parts by weight of acrylic thermoplastic elastomer (manufactured by Kuraray Co., Ltd .: Clarity LA2140e) Heat radiation filler: 108 parts by weight of synthetic magnesite (manufactured by Kamishima Chemical Industries, Ltd .: MSL)

[Production of film sheet]
The production procedure of the film sheet 8 of Example 2 was as follows. First, an acrylic thermoplastic elastomer was dissolved in toluene (120 parts by weight), and then synthetic magnesite was dispersed with a paint shaker to generate a coating solution. Next, the coating liquid was applied onto the peeled PET film using a baker applicator, and dried at 80 ° C. for 1 minute to produce a film sheet 8 having a thickness of 100 μm.

[Print dot pattern]
In Example 2, as in Example 1, a dot pattern was printed on one surface of the produced film sheet 8 using a screen printing apparatus. The ink material, printing conditions, ink film thickness, pattern shape, and area ratio are the same as in Example 1.

[Sheet molding]
In Example 2, with respect to the molding of the sheet, as in Example 1, nine film sheets on which silver paste ink was screen-printed were laminated, and one film not printed on the uppermost layer was laminated. And these 10 film sheets were hot-pressed and formed into one sheet 1 to obtain a sheet 1 (base material 80) having a thickness of 1 mm.

[Comparative Example 2]
A film sheet 8 was produced using the same material as in Example 2, and only the film sheet 8 was laminated without printing a dot-like pattern, followed by press molding to obtain a sheet of Comparative Example 2. The sheet thickness of Comparative Example 2 is 1.0 mm.

Example 3
In Example 3, each material used for film formation of the film sheet 8, its substance name, and the weight ratio according to material are shown below.

Base resin: hydrogenated styrene-based thermoplastic elastomer (Asahi Kasei Chemicals Co., Ltd .: Tuftec H1221) 60 parts by weight Heat-dissipating filler: synthetic magnesite (Kanjima Chemical Co., Ltd .: MSL) 90 parts by weight

[Production of film sheet]
In Example 3, regarding the production of a film sheet, first, a hydrogenated styrene-based thermoplastic elastomer was dissolved in toluene (150 parts by weight), and then synthetic magnesite (MSL) was dispersed with a paint shaker to obtain a coating solution. Generate. Next, the coating liquid was applied onto the peeled PET film using a baker applicator, and dried at 80 ° C. for 1 minute to produce a film sheet having a thickness of 100 μm.

[Print dot pattern]
In Example 3, as in Examples 1 and 2, a dot-like pattern was printed on one surface of the produced film sheet 8 using a screen printing apparatus. The ink material, printing conditions, ink film thickness, pattern shape, and area ratio are the same as in Examples 1 and 2.

[Sheet molding]
In Example 3, with respect to sheet formation, nine film sheets on which silver paste ink was screen-printed were laminated, and one film sheet not printed on the uppermost layer was laminated, as in Examples 1 and 2. And these 10 film sheets were hot-pressed and formed into one sheet 1 to obtain a sheet 1 (base material 80) having a thickness of 1 mm.

[Comparative Example 3]
A film sheet 8 was produced using the same material as in Example 3, and only the film sheet 8 was laminated without printing a dot-like pattern, followed by press molding to obtain a sheet 1 of Comparative Example 3. The thickness of the sheet 1 of Comparative Example 3 is 1.0 mm.

[Verification]
In Examples 1, 2, and 3, in order to verify the heat dissipation and insulation of the sheet 1, the thermal diffusivity and volume resistivity of the obtained sheet 1 were measured. Similarly, measurements were performed for Comparative Examples 1, 2, and 3, and comparisons were made with Examples 1, 2, and 3, respectively. In addition, in an Example and a comparative example, the heat dissipation of the sheet | seat 1 is verified by measuring a thermal diffusivity instead of the thermal conductivity demonstrated by one Embodiment.

[Measurement of thermal diffusivity]
Here, about the thermal diffusivity, it measured with the temperature wave thermal analysis method using the thermal diffusivity measuring apparatus (eye phase mobile 1u) made from an eye phase.

(Measurement of volume resistivity)
The volume resistivity was measured using a high resistivity meter (Hiresta UP MCP-HT450) manufactured by Mitsubishi Chemical Analytech Co., Ltd. The volume resistivity was measured at a standard temperature (23 ° C.).

〔Measurement result〕
FIG. 7 is a table showing the thermal diffusivity and volume resistivity of the sheets 1 of Examples 1, 2, and 3 and the sheets 1 of Comparative Examples 1, 2, and 3 in comparison.

As shown in the table in FIG. 7, the thermal diffusivity of the sheet 1 of Example 1 was 24.1 (× 10 ⁻⁷ m ² / s). On the other hand, the thermal diffusivity of the sheet 1 of Comparative Example 1 was 15.0 (× 10 ⁻⁷ m ² / s). About the volume resistivity of the sheet | seat 1 of Example 1 and Comparative Example 1, all were 10 < ¹³ > (omega | ohm) * m or more.

The thermal diffusivities of the sheet 1 of Example 2 and Comparative Example 2 were 4.8 (× 10 ⁻⁷ m ² / s) and 1.5 (× 10 ⁻⁷ m ² / s), respectively. Moreover, the thermal diffusivity of the sheet 1 of Example 3 and Comparative Example 3 was 6.7 (× 10 ⁻⁷ m ² / s) and 4.0 (× 10 ⁻⁷ m ² / s), respectively. . The volume resistivity of Examples 2 and 3 and Comparative Examples 2 and 3 was 10 ¹³ Ω · m or more, as in Examples 1 and Comparative Example 1.

[Selection of volume resistivity]
FIG. 8 is a table showing the volume resistivity of a general insulating material. Moreover, FIG. 9 is a table | surface which shows the volume resistivity of the electrically-conductive material which contained the heat dissipation filler and gave electroconductivity. FIG. 9 shows various volume resistivity values of Shin-Etsu Silicone (conductive silicone rubber) manufactured by Shin-Etsu Chemical Co., Ltd.

Each of the insulating materials shown in FIG. 8 has a volume resistivity of 10 ¹⁰ Ω · m or more. Further, the volume resistivity of each conductive material shown in FIG. 9 is 10 ¹ Ω · m or less.
From here, the inventors of the present invention, when verifying the insulating properties of the sheet 1 obtained in Example 1, have an appropriate volume resistivity (10 ¹⁰ Ω · m or more) for ensuring the insulating properties ( Threshold).

[Verification of heat dissipation]
The inventor of the present invention studied the following about the heat dissipation of the sheet 1.
[Evaluation results of Examples and Comparative Examples]
From the measured values shown in the table in FIG. 7, the thermal diffusivity of the sheet 1 of Example 1 is higher than the thermal diffusivity of the sheet of Comparative Example 1. Similarly, in the thermal diffusivity of the sheet 1 of Example 2 and Comparative Example 2, the thermal diffusivity of the sheet 1 of Example 2 is greater than that of the sheet 1 of Example 3 and Comparative Example 3. The sheet 1 of Example 3 has a higher thermal diffusivity.
From the above results, it is understood that the thermal diffusivity of the sheet 1 is improved by printing the dot pattern on the film sheet 8 (the heat dissipation path 18 is formed in the completed state).

  Note that the base resin (HRLC-1), which is the material of the sheet 1 obtained in Example 1 and Comparative Example 1, contains some heat-dissipating filler in advance, and therefore has a certain amount of heat-dissipation from the beginning. doing. That is, in the film sheet 8 of Example 1 and Comparative Example 1, the heat radiating fillers (MSL and MSS) are further included in the heat radiating base resin.

  On the other hand, the base resin (clarity LA2140e, Tuftec H1221) used in Examples 2 and 3 and Comparative Examples 2 and 3 does not contain a heat radiation filler in advance. That is, in the film sheets 8 of Examples 2 and 3 and Comparative Examples 2 and 3, a heat radiating filler (MSS) is included in the base resin that does not have heat radiating properties.

  That is, in Example 1, since not only the heat dissipating fillers (MSL and MSS) and the dot pattern, but also the heat dissipating filler previously contained in the base resin contributes to the improvement of heat dissipation, As a result, the sheet 1 has a much higher thermal diffusivity than the sheets 1 of Examples 2 and 3.

[Verification of insulation]
Next, the inventor of the present invention conducted the following investigation on the insulating properties of the sheet 1.
From the measured values shown in FIG. 7, the volume resistivity of the sheet 1 obtained in Examples 1, 2, and 3 is 10 ¹³ Ω · m or more, and is an optimal value (10 ¹⁰ Ω · m or more). I know that there is. From this result, it can be seen that the insulating properties of the sheets 1 obtained in Examples 1, 2, and 3 are sufficiently secured.

The present invention is not limited to the above-described embodiment, and various modifications can be made. For example, in the printing process in the manufacturing method of the sheet 1 according to an embodiment, a dot-like pattern is printed on the film sheet 8 using a gravure printing device, but the pattern is printed by a screen printing device, a flexographic printing device, or the like. May be.
In addition to the electronic component 4, the sheet 1 can be installed on various heating elements.

DESCRIPTION OF SYMBOLS 1 Sheet 8 Film sheet 8a Thin film part 10 Wafer part 18 Heat radiation path 80 Base material

Claims (6)

  A sea-island structure in which a resin having a thickness is used as a sea component, and a plurality of wafer portions containing heat dissipating fillers scattered in a direction perpendicular to the thickness direction in the resin is used as an island component, is formed at each position on the island. A sheet in which a plurality of the wafer parts are arranged side by side on the same line as viewed in the thickness direction of the resin, and the individual wafer parts are arranged apart from each other in the resin.   A sea-island structure having a resin having a thickness and containing a heat dissipating filler as a sea component, and a plurality of wafer portions containing heat dissipating fillers scattered in a direction perpendicular to the thickness direction in the resin as island components And a plurality of the wafer portions arranged on the same line as viewed in the thickness direction of the resin at each position of the island, and the individual wafer portions are arranged apart from each other in the resin. . In the sheet according to claim 1 or 2,
The wafer portion is
A sheet characterized in that the sheets are regularly arranged at regular intervals when viewed in a direction perpendicular to the thickness direction of the resin. A film forming step of forming a film sheet by forming a resin material;
Using a thermally conductive ink containing a heat dissipating filler, a printing step of printing a dot-like pattern distributed on one surface of the film sheet;
Forming a sheet by laminating a plurality of film sheets with a pattern obtained in the printing process so that each pattern overlaps in the thickness direction, and laminating the film sheet obtained in the film forming process on the uppermost layer The manufacturing method of the sheet | seat which has a process. A film forming step of forming a film sheet by forming a resin material containing a heat dissipating filler; and
Using a thermally conductive ink containing a heat dissipating filler, a printing step of printing a dot-like pattern distributed on one surface of the film sheet;
Forming a sheet by laminating a plurality of film sheets with a pattern obtained in the printing process so that each pattern overlaps in the thickness direction, and laminating the film sheet obtained in the film forming process on the uppermost layer The manufacturing method of the sheet | seat which has a process. In the manufacturing method of the sheet | seat of Claim 4 or 5,
In the printing process,
A method for producing a sheet, comprising: printing a dot pattern regularly arranged at a predetermined interval on one surface of the film sheet.

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