JP2013089843A - Thermal conductive sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a thermal conductive sheet that is easy to handle even when the thermal conductive sheet has a small thickness.SOLUTION: First and second insulating sheets 12 and 13 are disposed on both surfaces of a graphite sheet 11, and first and second release sheets 15 and 16 are further disposed thereon. An adhesive force of the first insulating sheet 12 and the first release sheet 15 is stronger than an adhesive force of the second insulating sheet 13 and the second release sheet 16. The first release sheet 15 includes a slit line 17 that divides an area provided with a thermal conductive sheet 14 into a first region 18 and a second region 19. The area of the first region 18 is three times or more of the area of the second region 19. The outer periphery of the thermal conductive sheet 14 and the slit line 17 intersect each other through at least two points. The thermal conductive sheet 14 and the slit line 17 intersect at approximately right angles at one intersection point 20, and intersect at an acute angle at the other intersection point 21.

Description

  The present invention relates to a heat conductive sheet used for an electronic device having a heat generating component inside a mobile phone, a digital camera or the like.

  With recent downsizing and higher performance of electronic equipment, the amount of heat generated from heat-generating parts such as semiconductor parts and battery packs must be increased and countermeasures must be taken. Graphite sheets are used due to their high thermal conductivity. It is getting to be. Further, in connection with downsizing, there is a demand for a thinner thermal conductive sheet with respect to reduction in thickness. Usually, as shown in FIG. 4, such a heat conductive sheet is used in which a pressure-sensitive adhesive tape 2 is bonded to both surfaces of a graphite sheet 1, and a sheet in which a protective sheet 3 is bonded to both surfaces for handling. ing.

  As prior art document information related to the invention of this application, for example, Patent Document 1 is known.

JP 2010-149509 A

  When the thickness of the above conventional heat conductive sheet was thick, it was not a big problem, but when this became very thin, the heat conductive sheet would peel off or curl when peeling off the protective tape. It was easy to happen that it became impossible to use. On the other hand, an object of this invention is to provide the heat conductive sheet which is easy to handle even if the thickness of a heat conductive sheet becomes thin.

  In order to solve the above problems, the present invention provides a first insulating sheet that covers the graphite sheet on the first surface of the graphite sheet, and a second surface that covers the graphite sheet on the second surface opposite to the first surface. A heat conductive sheet provided with an insulating sheet, further comprising a first release sheet covering the first insulating sheet and a second release sheet covering the second insulating sheet, the first insulating sheet and the first The adhesive strength between the release sheet and the second insulating sheet is greater than the adhesive strength between the second insulating sheet and the second release sheet. The slit line is divided into two areas, the area of the first area is three times or more than the area of the second area, and the outer periphery of the heat conductive sheet and the slit line intersect at least at two points. , At one intersection Intersecting the corner, on the other hand the intersection is obtained so as to intersect at an acute angle.

  With the above configuration, even if the heat conductive sheet becomes thin, the release sheet can be peeled without damaging or deforming the heat conductive sheet, and the heat conductive sheet can be easily installed at a predetermined position. .

The perspective view of the heat conductive sheet in one embodiment of this invention The exploded view of the heat conductive sheet in one embodiment of the present invention Manufacturing method of heat conductive sheet in one embodiment of the present invention Sectional view of a conventional heat conductive sheet

  Hereinafter, the heat conductive sheet in one embodiment of the present invention is explained, referring to drawings.

  FIG. 1 is a perspective view of a heat conductive sheet in an embodiment of the present invention, and FIG. 2 is an exploded view thereof. 1 and 2, a pyrolytic graphite sheet 11 having a thickness of about 20 μm, a first insulating sheet 12 made of double-sided tape having a thickness of about 8 μm covering the first surface of the graphite sheet 11, and the graphite sheet 11 A heat conductive sheet 14 is constituted by a second insulating sheet 13 made of an insulating tape having a thickness of about 8 μm covering the second surface. Further, a first release sheet 15 that covers the first insulating sheet 12 side of the heat conductive sheet 14 is bonded to a second release sheet 16 that covers the first insulating sheet 13 side. .

  The first insulating sheet 12 is obtained by applying an acrylic adhesive on both sides of a PET (polyethylene terephthalate) sheet, and the second insulating sheet 13 is provided with an acrylic adhesive on one side of the PET sheet. The surface to which the adhesive material is applied is bonded to the graphite sheet 11. The first release sheet 15 is made of PET as a base material, and a silicone release material is applied to the surface to be bonded to the first insulating sheet 12. The second release sheet 16 is made of PET as a base material, and an acrylic adhesive material is applied to the surface to be bonded to the first insulating sheet 12. By doing in this way, the adhesive force per unit width between the 1st insulating sheet 12 and the 1st peeling sheet 15 is about 0.1 N / 25mm, and the 2nd insulating sheet 13 and the 2nd peeling sheet It is comprised so that the adhesive force per unit width between 16 may be set to about 0.05 N / 25mm. As described above, the adhesive force between the first insulating sheet 12 and the first release sheet 15 is made stronger than the adhesive force between the second insulating sheet 13 and the second release sheet 16. I have to.

  The first release sheet 15 is provided with a slit line 17, and the region of the heat conductive sheet 14 is divided by the slit line 17 when bonded to the heat conductive sheet 14. The larger area of the divided areas is the first area 18, the smaller area is the second area 19, and the area of the first area 18 is about four times the area of the second area 19. Further, the outer contour line of the heat conductive sheet 14 and the slit line 17 intersect at two points, one intersecting point 20 intersects at a substantially right angle, and the other intersecting point 21 intersects at about 25 °.

  The first release sheet 15 includes the entire second release sheet 16 and is formed to be larger than the second release sheet 16 on the first region 18 side.

  By configuring as described above, when the heat conductive sheet is installed at a predetermined position, first, the first release sheet 15 is connected from the heat conductive sheet 14 to the one intersection at the portion bonded in the first region 18. Peel off starting at 20. At this time, in the second region 19, the entire second release sheet 16 is held from the first release sheet 15, and the first release sheet on the first region 18 side which is larger than the second release sheet 16. Hold only 15 and peel. Since the starting point is one intersection 20 that intersects substantially at right angles, the adhesive force between the first insulating sheet 12 and the first release sheet 15 is reduced between the second insulating sheet 13 and the second release sheet 16. Even if it is stronger than the adhesive strength between them, it can be peeled off without any problem.

  Here, the term “substantially perpendicular” means that peeling is possible as in the present embodiment, specifically 90 ± 5 °.

  Next, the part bonded in the second region 19 is peeled off with the other intersection 21 as the starting point. Here, the second release sheet 16 is provided with a blank portion 22 protruding from the heat conductive sheet 14 on the first region 18 side, and the first region 18 side holds this blank portion 22 while Is peeled off at the intersection 21 of the starting point. At the other intersection point 21, the outer contour line of the heat conductive sheet 14 and the slit line 17 intersect at an acute angle, so that the adhesive force between the first insulating sheet 12 and the first release sheet 15 is the second Even if it is stronger than the adhesive force between the insulating sheet 13 and the second release sheet 16, it can be released without any problem.

  In this way, when the material bonded with the adhesive material is peeled off, the force for peeling is proportional to the width of the peeling, so when the width suddenly increases as it peels off, the force for peeling suddenly increases. Therefore, the sheet is easily damaged. Therefore, when the second region 19 is peeled off, the vicinity of the starting point of the peeling needs to intersect at a small angle, and the angle at which the outer contour line of the heat conductive sheet 14 and the slit line 17 intersect at the other intersection 21 is 45 °. Is preferably less than 30 °, more preferably 30 ° or less.

  In the above embodiment, the first insulating sheet is a double-sided tape and the second insulating tape is a single-sided adhesive tape, but both may be double-sided tape or both may be a single-sided adhesive tape. The effect of this invention can be acquired by providing a slit line in the peeling tape of the side with strong adhesive force.

  In the present embodiment, the pyrolytic graphite sheet is used as the graphite sheet. However, the present invention is not limited to this, and it may be an expanded graphite sheet.

  FIG. 3 is a diagram illustrating a method for producing a heat conductive sheet according to an embodiment of the present invention.

  First, as shown in FIG. 3A, a slit line 17 and a feed hole are formed on a sheet material in which a PET film for forming the first release sheet 15 is bonded to a support film (not shown) having slight adhesiveness. Form. The slit line 17 is formed by pressing using a punching die, and only the PET film for forming the first release sheet 15 is cut. The feed hole is pressed by using a punch die, and the support film is also penetrated. This feed hole is for moving the sheet material for progressive formation, and thus forms the first release sheet 15.

  Next, as shown in FIG. 3 (b), the release sheet adhesively fixed to the sheet material composed of the insulating sheet is peeled onto the first release sheet 15 to expose the adhesive processed surface. , Stick the adhesive processed surface together. Thereafter, the pressure is applied to fix the adhesive. Thereafter, the release sheet that is adhesively fixed to the other adhesive processing surface is peeled to expose the adhesive processing surface to form the first insulating sheet 12.

  Next, as shown in FIG. 3C, the graphite sheet 11 that has been punched into a predetermined shape in advance is placed on a predetermined position of the first insulating sheet 12.

  Next, as shown in FIG. 3 (d), the release sheet that is adhesively fixed to the sheet material composed of the insulating sheet is peeled off on the graphite sheet 11 to expose the adhesive processing surface, and the adhesive processing surface. The second insulating sheet 13 is formed by bonding, pressurizing, and adhering and fixing.

  Next, as shown in FIG. 3 (e), in order to remove in advance the first insulating sheet 12 and the second insulating sheet 13 located immediately below the portion that becomes the gripping tongue 23, a press is used to press. And cut.

  Next, as shown in FIG. 3 (f), a release sheet coated with an adhesive material on one side is applied to the one formed in FIG. 3 (d), and the surface coated with the adhesive material is applied to the heat conductive sheet. Combine, press and fix.

  Next, as shown in FIG. 3G, after pressing into a predetermined shape using a punching die, unnecessary portions are removed to form a second release sheet 16.

  Next, as shown in FIG.3 (h), it cut | disconnects to a predetermined shape and is separated into pieces, and a heat conductive sheet is completed.

  In this embodiment, lamination is performed in order. However, an insulating sheet previously bonded to both surfaces of a graphite sheet may be bonded to a release sheet.

  Alternatively, the heat conductive sheets may be attached to a predetermined position while being removed one by one from the state shown in FIG.

  Next, how to use the heat conductive sheet in one embodiment of the present invention will be described. The first region 18 of the first release sheet 15 that is adhesively fixed to the heat conductive sheet 14 is peeled off from one intersection 20 as a starting point with respect to a predetermined sticking surface for heat countermeasures of the heat-generating component. Next, the gripping tongue 23 of the first release sheet 15 is gripped, and the other intersection 21 is peeled off as a starting point. Thereby, the constituent articles of the heat conductive sheet 14 and the second release sheet 16 can be taken out. Here, although the adhesive force between the second release sheet 16 and the second insulating sheet 13 is low, the angle between the slit line 17 at the other intersection 21 and the outer periphery of the heat conductive sheet is an acute angle. Thus, it is possible to easily start peeling from the second region 19 of the first release sheet 15. Furthermore, since the area of the second region 19 is small, the necessary peeling force from the start of peeling to the complete peeling can be kept low, and even from a thin thermal conductive sheet, the second peeling sheet 16 It can be taken out without falling off or damaging or deforming the heat conductive sheet itself. Here, in order to obtain the above effect, it is desirable that the area of the first region 18 is three times or more the area of the second region 19.

  Then, the constituent articles of the heat conductive sheet 14 and the second release sheet 16 taken out are attached to a predetermined surface. When the second release sheet 16 is pasted, the surface accuracy is maintained so that bubbles and wrinkles are not generated in the heat conductive sheet 14. After pasting in this way, the adhesion is stabilized by pressing or the like, and the gripping tongue 23 of the second release sheet 16 is gripped and peeled off. This completes the pasting. When the thickness of the heat conductive sheet is reduced, handling thereof becomes difficult. However, by applying as described above in the configuration of the present invention, the total thickness of the heat conductive sheet 14 is less than 40 μm. Even if it can be pasted stably.

  The heat conductive sheet according to the present invention can provide a heat conductive sheet that is easy to handle even when the thickness is reduced, and is industrially useful.

DESCRIPTION OF SYMBOLS 11 Graphite sheet 12 1st insulating sheet 13 2nd insulating sheet 14 Thermal conductive sheet 15 1st peeling sheet 16 2nd peeling sheet 17 Slit line 18 1st area | region 19 2nd area | region 20 One intersection 21 Other Intersection 22 Margin 23 Grab tongue

Claims (3)

A heat conductive sheet in which a first insulating sheet covering the graphite sheet is provided on the first surface of the graphite sheet, and a second insulating sheet covering the graphite sheet is provided on the second surface opposite to the first surface. Further, a first release sheet that covers the first insulating sheet and a second release sheet that covers the second insulating sheet are provided, and adhesion between the first insulating sheet and the first release sheet is provided. The force is stronger than the adhesive force between the second insulating sheet and the second release sheet, and the first release sheet has a portion where the heat conductive sheet is provided as the first region and the second region. A slit line that is divided into two regions, the area of the first region being three times or more the area of the second region, and at least two points on the outer periphery of the thermal conductive sheet and the slit line. Cross at , They intersect at approximately a right angle at one of the intersections, the heat conductive sheet, characterized in that intersects at an acute angle in the other intersection. The heat conduction sheet according to claim 1, wherein the other intersection intersects at an angle of less than 45 °. The heat conductive sheet according to claim 1, wherein an area of the first release sheet is larger than an area of the second release sheet.

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