Original sheet

Abstract

To provide an original plate sheet capable of suppressing dropout of a resin composition that constitutes an insulation layer.SOLUTION: An original plate sheet according to the present invention is an original plate sheet used for cutting out at least one insulation heat radiation sheet, comprising a first sheet that is a laminated sheet having an insulation layer laminated on a substrate layer and a second sheet laminated on the insulation layer of the first sheet. The insulation layer is composed of a resin composition including resin and inorganic filler, at least a part of the first sheet extends outward from the second sheet, and the insulation layer has an exposed part that is exposed outside of the outer edge of the second sheet.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a master sheet, and more particularly to a master sheet used for cutting out an insulating and heat-dissipating sheet. [Background technology]

[0002] BACKGROUND ART Conventionally, in the electronics field, it is known to use insulating sheets to ensure insulation in semiconductor modules and the like (for example, Patent Document 1 below). A conventionally known insulating sheet is an insulating and heat-dissipating sheet in which an insulating layer having good thermal conductivity is formed from a resin composition containing a resin and an inorganic filler. As the insulating heat dissipation sheet, for example, one in which an insulating layer having excellent thermal conductivity and electrical insulation properties is sandwiched between two sheets of copper foil is known. The insulating heat dissipation sheet may be used by being removably interposed between a semiconductor module and a heat sink, or by peeling one or both copper foils from the insulating layer and adhering the insulating layer to the semiconductor module or heat sink. Therefore, the insulating layer may be made of a resin composition containing an epoxy resin with excellent adhesiveness and an inorganic filler with excellent thermal conductivity.

[0003] In cases where it is expected that the insulating heat dissipation sheet will be adhered to an adherend such as a semiconductor module or a heat sink, one or both of the copper foils in the insulating heat dissipation sheet may be replaced with a separator sheet such as release paper or release film. The insulating and heat-dissipating sheet as described above is produced by first preparing a master sheet larger than the insulating and heat-dissipating sheet in question, and then cutting the sheet out of the master sheet using a technique such as a punching press.

[0004] The base sheet is produced using a laminated sheet including a base layer made of, for example, copper foil and an insulating layer made of a resin composition. The original sheet is produced by laminating a first sheet, which is the laminated sheet, and a second sheet that is different from the first sheet. The second sheet may be the same laminate sheet or separator sheet as the first sheet. That is, the original sheet is produced by laminating two sheets including a laminated sheet. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2010-094887 Summary of the Invention [Problem to be solved by the invention]

[0006] Since an insulating and heat-dissipating sheet is required to have excellent thermal conductivity, the insulating layer usually contains a high amount of inorganic filler. When producing the base plate sheet, the base plate sheet may be compressed in the thickness direction to harden the resin composition that constitutes the insulating layer. In such cases, the resin composition that constitutes the insulating layer may protrude beyond the copper foil, separator sheet, etc. A resin composition with a high content of inorganic filler is usually more brittle than the resin alone. Therefore, the resin composition that protrudes from the edge portion of the base sheet is more likely to fall off from the base sheet than the resin composition that is supported by the base layer. The resin composition that falls off may become foreign matter and cause various problems.

[0007] Until now, no attention has been paid to the fact that the resin composition that constitutes the insulating layer is the cause of foreign matter in this manner, and no sufficient measures have been taken to prevent the resin composition that constitutes the insulating layer from falling off. Therefore, with the conventional base plate sheets, there is a problem in that it is difficult to prevent the resin composition that constitutes the insulating layer from falling off.

[0008] Therefore, in order to solve the above problems, an object of the present invention is to provide a base sheet that can prevent the resin composition that constitutes the insulating layer from falling off. [Means for solving the problem]

[0009] The base sheet according to the present invention is A base sheet used to cut out at least one insulating and heat-dissipating sheet, a first sheet which is a laminated sheet in which an insulating layer is laminated on a base material layer; a second sheet laminated on the insulating layer of the first sheet, the insulating layer is made of a resin composition containing a resin and an inorganic filler, At least a portion of the first sheet extends outward beyond the second sheet, and the insulating layer has an exposed portion that is exposed outside the outer periphery of the second sheet.

[0010] According to this configuration, at least a portion of the first sheet extends outward beyond the second sheet, and the insulating layer has an exposed portion that is exposed outside the outer edge of the second sheet. Therefore, when the original plate sheet is compressed in the thickness direction during production of the original plate sheet, the exposed portion can be moved toward a portion that does not overlap with the second sheet. This makes it possible to prevent the resin composition constituting the insulating layer from spilling out beyond the base material layer when producing the base sheet. As a result, the resin composition constituting the insulating layer of the base sheet can be prevented from falling off.

[0011] In the above original sheet, The first sheet and the second sheet are both rectangular in plan view, the first sheet and the second sheet are laminated such that one side of the first sheet and one side of the second sheet are parallel to each other at a distance from each other, and the side of the second sheet is positioned more inward than the side of the first sheet; It is preferable that the exposed portion is provided between the two sides.

[0012] According to this configuration, the exposed portion is provided between two parallel sides, so that when the original sheet is compressed in the thickness direction during production of the original sheet, it becomes easier to uniformly move the exposed portion toward the portion that does not overlap with the second sheet. This makes it possible to further prevent the resin composition constituting the insulating layer from spilling out beyond the base material layer when producing the base sheet. As a result, the resin composition constituting the insulating layer of the base sheet can be further prevented from falling off.

[0013] In the above original sheet, The second sheet is preferably a separator sheet provided so as to be releasable from the insulating layer.

[0014] According to this configuration, the second sheet is a separator sheet and does not have an insulating layer made of a resin composition like a laminate sheet. Therefore, when the base sheet is compressed in the thickness direction during production, deformation in the width direction caused by the resin composition can be suppressed. Therefore, when the original sheet is compressed in the thickness direction during production of the original sheet, the exposed portion can be easily moved along the side edge of the second sheet. This makes it possible to more sufficiently prevent the resin composition constituting the insulating layer from spilling out beyond the base material layer when producing the base sheet. As a result, the resin composition constituting the insulating layer of the base sheet can be more sufficiently prevented from falling off.

[0015] In the above original sheet, the second sheet is the same laminated sheet as the first sheet, the first sheet and the second sheet are stacked with a diagonal offset, It is preferable that the insulating layer of the second sheet also has an exposed portion that is exposed on the outside of the first sheet.

[0016] According to this configuration, when the original sheet is compressed in the thickness direction during production of the original sheet, it becomes easier to move the exposed portion more uniformly toward the portion that does not overlap with the second sheet. This makes it possible to further prevent the resin composition constituting the insulating layer from spilling out beyond the base material layer when producing the base sheet. As a result, the resin composition constituting the insulating layer of the base sheet can be further prevented from falling off.

[0017] In the above original sheet, It is preferable that the length by which the exposed portion of the second sheet extends outward beyond the first sheet is 10 mm at most.

[0018] According to this configuration, when the original sheet is compressed in the thickness direction during production of the original sheet, it becomes easier to move the exposed portion more sufficiently toward the portion that does not overlap with the second sheet. This makes it possible to further prevent the resin composition constituting the insulating layer from spilling out beyond the base material layer when producing the base sheet. As a result, the resin composition constituting the insulating layer of the base sheet can be further prevented from falling off.

[0019] In the above original sheet, It is preferable that the length by which the exposed portion of the first sheet extends outward beyond the second sheet is a maximum of 10 mm.

[0020] According to this configuration, when the original sheet is compressed in the thickness direction during production of the original sheet, the exposed portion can be more easily moved toward the portion that does not overlap with the second sheet. This makes it possible to further prevent the resin composition constituting the insulating layer from spilling out beyond the base material layer when producing the base sheet. As a result, the resin composition constituting the insulating layer of the base sheet can be further prevented from falling off. [Effects of the Invention]

[0021] According to the present invention, it is possible to provide a base plate sheet that can suppress the falling off of the resin composition that constitutes the insulating layer. [Brief explanation of the drawings]

[0022] [Figure 1] 1A is a perspective view showing the overall configuration of an original sheet according to a first embodiment of the present invention, and FIG. 1B is a side view of the original sheet according to the first embodiment of the present invention, seen from the y-axis direction. [Figure 2] 1A is a perspective view showing the overall configuration of a master sheet according to a second embodiment of the present invention, FIG. 1B is a side view of the master sheet according to the second embodiment of the present invention, as viewed from the y-axis direction, and FIG. 1C is a side view of the master sheet according to an embodiment of the present invention, as viewed from the x-axis direction. [Figure 3] FIG. 3 is a side view from the y-axis direction showing the original plate sheet according to the first embodiment compressed in the thickness direction. [Figure 4] 10A is a side view from the y-axis direction showing a state in which an original sheet according to a second embodiment is compressed in the thickness direction, and FIG. 10B is a side view from the x-axis direction showing a state in which an original sheet according to a second embodiment is compressed in the thickness direction. [Figure 5] FIG. 4 is a perspective view showing another overall configuration of the original sheet according to the first embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0023] The base sheet according to the present invention will be described below. The original sheet according to the present invention is used to cut out at least one insulating and heat-dissipating sheet. The base sheet according to the present invention comprises a first sheet which is a laminated sheet in which an insulating layer is laminated on a base layer, and a second sheet laminated on the insulating layer of the first sheet. In the base sheet according to the present invention, the insulating layer is made of a resin composition containing a resin and an inorganic filler. In the original sheet of the present invention, at least a portion of the first sheet extends outward beyond the second sheet, and the insulating layer has an exposed portion that is exposed outside the outer peripheral edge of the second sheet.

[0024] The original sheet may have dimensions in a plan view that allow one insulating and heat-dissipating sheet to be cut out. The original sheet may have dimensions in a plan view that allow a plurality of insulating and heat-dissipating sheets to be cut out. The dimensions of the original sheet in a plan view are set to an appropriate size depending on the purpose.

[0025] In the original sheet according to the present invention, it is preferable that both the first sheet and the second sheet are rectangular in plan view. Furthermore, in the original sheet of the present invention, it is preferable that the first sheet and the second sheet are laminated so that one side of the first sheet and one side of the second sheet are parallel to each other at a distance, and the side of the second sheet is positioned more inward than the side of the first sheet, and the exposed portion is provided between the two sides.

[0026] (First embodiment) Hereinafter, first, referring to Figures 1(a) and (b), we will explain an example of an original sheet according to the first embodiment of the present invention, in which the first sheet and the second sheet are both rectangular in plan view and the second sheet is a separator sheet. In FIG. 1(a), the original sheet 10 according to the first embodiment of the present invention will be described with the z-axis direction being the height direction, the y-axis direction being the width direction, and the x-axis direction being the length direction.

[0027] As shown in Figures 1(a) and (b), the original sheet 10 of the first embodiment comprises a first sheet 1, which is a laminated sheet in which an insulating layer 1b is laminated on a base material layer 1a, and a second sheet 2 laminated on the insulating layer 1b of the first sheet 1. As described above, in the original sheet 10 according to the first embodiment, the second sheet is a separator sheet.

[0028] In the original sheet 10 according to the first embodiment, the first sheet 1 and the second sheet 2 are configured in a rectangular shape with approximately the same dimensions in a plan view. As shown in FIG. 1(a), the first sheet 1 has a first side E1a and a second side E1b that are spaced apart in the x-axis direction and extend parallel to each other along the y-axis direction, and a third side E1c and a fourth side E1d that are spaced apart in the y-axis direction and extend parallel to each other along the x-axis direction. The first side E1a and the second side E1b, and the third side E1c and the fourth side E1d are joined at right angles to each other in a plan view, forming a rectangle of the first sheet 1 in a plan view. Like the first sheet 1, the second sheet 2 also has a first' side E2a and a second' side E2b arranged at a distance in the x-axis direction and extending parallel to each other along the y-axis direction, and a third' side E2c and a fourth' side E2d arranged at a distance in the y-axis direction and extending parallel to each other along the x-axis direction. The first' side E2a and the second' side E2b, and the third' side E2c and the fourth' side E2d are joined at right angles to each other in plan view, forming a rectangle of the second sheet 2 in plan view.

[0029] As shown in Figures 1(a) and (b), in the original sheet 10 of the first embodiment, the second sheet 2 is misaligned with the first sheet 1 in the longitudinal direction (x-axis direction), with the third' side E2c and the fourth' side E2d, which are arranged at a distance in the width direction (y-axis direction), overlapping the third side E1c and the fourth side E1d of the first sheet 1, which are arranged at a distance in the width direction (y-axis direction), respectively. That is, in the original sheet 10 of the first embodiment, on one side in the longitudinal direction, the first side E1a of the first sheet 1 and the first' side E2a of the second sheet 2 are parallel and spaced apart so that the first' side E2a is positioned more inward than the first side E1a, and an exposed portion Ex1 of the first sheet 1 is provided between the first side E1a and the first' side E2a. In the original sheet 10 according to the first embodiment, the exposed portion Ex1 is provided, so that part of the insulating layer 1b of the first sheet 1 is exposed on the surface. In addition, in the original sheet 10 of the first embodiment, an exposed portion Ex2 of the second sheet 2 is provided on the other side of the longitudinal direction between the second edge E1b of the first sheet 1 and the second' edge E2b of the second sheet 2, and by providing such an exposed portion Ex2, a portion of the surface of the separator sheet, which is the second sheet 2, on the side that is laminated with the first sheet 1 is exposed.

[0030] The length by which the exposed portion Ex1 of the first sheet 1 extends outward beyond the second sheet 2 is preferably 10 mm at most. The length may be 8 mm or less, 7 mm or less, or 6 mm or less. The length may be 2 mm or more, 3 mm or more, or 4 mm or more.

[0031] The base material layer 1a of the first sheet 1 is made of any of various known base material sheets. Examples of the substrate sheet that can be used include resin films such as polyester resin films, polyolefin resin films, and polyimide films; and metal foils such as copper foils, aluminum foils, and nickel foils. The metal foil may be a clad material having multiple metal layers. Examples of resins constituting the polyester resin film include polyethylene terephthalate, and examples of resins constituting the polyolefin resin film include polyethylene resin, polypropylene resin, and ethylene-vinyl acetate copolymer resin. Among these, it is preferable to use a resin film made of polyethylene terephthalate resin as the base sheet constituting the base layer 1a, from the viewpoint of good shape formability and low cost. The surface of the base sheet constituting the base layer 1a that is to be laminated on the insulating layer 1b may be subjected to a roughening treatment (matt treatment) or a release treatment. Alternatively, the substrate sheet may be in an untreated state. By subjecting the base sheet to a release treatment, the base layer 1a of the first sheet 1 can be easily peeled off from the insulating layer 1b. Furthermore, by subjecting the base sheet to a surface roughening treatment, the insulating layer 1b can be more sufficiently held by the base layer 1a in the first sheet 1.

[0032] The second sheet, or separator sheet, may also be made of the same resin film as described above.

[0033] From the viewpoint of achieving excellent thermal conductivity, it is preferable to use a metal foil for the base layer 1a, and among metal foils, it is more preferable to use a copper foil or an aluminum foil. The copper foil may be subjected to an oxidation treatment such as blackening, or may be subjected to a matte treatment (surface roughening treatment) such as blasting. The aluminum foil may be one that has been subjected to an anodizing treatment such as an anodizing treatment with phosphate or an anodizing treatment with sulfate, or may be one that has been subjected to a sealing treatment or the like.

[0034] The thickness of the base layer 1a is not particularly limited. The thickness of the base layer 1a can be set to, for example, 0.02 mm (20 μm) or more. The thickness of the base layer 1a may be 0.05 mm or more, 0.1 mm or more, 0.2 mm or more, 0.3 mm or more, or 0.4 mm or more. The thickness of the base material layer 1a may be 0.5 mm or more, or may be 0.8 mm or more. The thickness of the base layer 1a can be set to, for example, 10 mm or less. The thickness of the base material layer 1a may be 8 mm or less, 6 mm or less, or 4 mm or less. The thickness of the base material layer 1a may be 3 mm or less, or may be 2 mm or less. The thickness of the base layer 1a can be measured using a micrometer or the like. Specifically, the thickness can be determined by measuring the thickness at 10 randomly selected locations on the base layer 1a using a micrometer or the like and calculating the arithmetic average of these measured values.

[0035] As described above, in the original sheet 10 according to the first embodiment, the insulating layer 1b of the first sheet 1 is made of a resin composition containing a resin and an inorganic filler.

[0036] Examples of the resin include thermoplastic resins and thermosetting resins.

[0037] Examples of the thermoplastic resin include polyolefin resin, polyvinyl chloride resin, phenoxy resin, acrylic resin, polyamide resin, polyamideimide resin, polyimide resin, polyetheramideimide resin, polyetheramide resin, and polyetherimide resin. Examples of the polyolefin resin include polyethylene resin, polypropylene resin, and ethylene-vinyl acetate copolymer resin.

[0038] Examples of the thermosetting resin include epoxy resin and phenol resin. Examples of the epoxy resin include bisphenol A type epoxy resin, modified bisphenol A type epoxy resin, bisphenol F type epoxy resin, modified bisphenol F type epoxy resin, triphenylmethane type epoxy resin, cresol novolac type epoxy resin, biphenyl type epoxy resin, dicyclopentadiene type epoxy resin, and phenol novolac type epoxy resin. These various epoxy resins may be used alone or in combination of two or more. Examples of the phenol resin include dicyclopentadiene type phenol resin, novolak phenol resin, cresol novolak resin, phenol aralkyl resin, and triphenylmethane type phenol resin. Among these, triphenylmethane-type phenolic resins are advantageous in terms of heat resistance, and phenol aralkyl resins are preferably used because they exhibit good adhesion to the adherend when adhering the insulating and heat-dissipating sheet to the adherend.

[0039] When an epoxy resin is used as the thermosetting resin, the resin composition may contain a curing agent or a curing accelerator for the epoxy resin in order to adjust the thermosetting properties of the epoxy resin. Examples of the curing agent that can be used include amine-based curing agents such as diaminodiphenyl sulfone, dicyandiamide, diaminodiphenylmethane, and triethylenetetramine, and acid anhydride-based curing agents. Furthermore, as the curing agent, a novolac phenol type phenolic resin or the like can also be used. Examples of the curing accelerator that can be used include imidazoles and amines, etc. Examples of the amines include triphenyl phosphate (TPP) and boron trifluoride monoethylamine.

[0040] When a phenolic resin is used as the thermosetting resin, the resin composition may contain a curing agent for the phenolic resin from the viewpoint of adjusting the thermosetting property of the phenolic resin. Examples of the curing agent include hexamethylenetetramine, various epoxy compounds having two or more functional groups, isocyanates, trioxane, and cyclic formals.

[0041] The inorganic filler is not particularly limited as long as it has a higher thermal conductivity than the resin. Examples of the inorganic filler include inorganic nitride fillers, inorganic oxide fillers, diamond, talc, clay, and calcium carbonate. Examples of the inorganic nitride filler include boron nitride, aluminum nitride, and silicon nitride. Examples of the inorganic oxide filler include silicon oxide (silica), aluminum oxide (alumina), titanium oxide (titania), and zirconium oxide (zirconia). Among these, the inorganic filler is preferably at least one selected from the group consisting of boron nitride, aluminum oxide, and silicon oxide. The inorganic filler is preferably a mixture containing boron nitride and aluminum oxide, a mixture containing boron nitride and silicon oxide, or a mixture containing boron nitride, aluminum oxide, and silicon oxide. In the mixture, the content of boron nitride is preferably 50% by mass or more and 95% by mass or less.

[0042] When the insulating layer 1b contains boron nitride as the inorganic filler, the content of boron nitride in the insulating layer 1b is preferably 30% by volume or more, more preferably 40% by volume or more, and even more preferably 50% by volume or more. When the content of boron nitride is 30% by volume or more, the insulating layer 1b has excellent thermal conductivity. On the other hand, from the viewpoint of making the insulating layer 1b exhibit excellent adhesiveness, mechanical strength, and electrical insulation properties, the content of boron nitride is preferably 75% by volume or less. The content of boron nitride in the insulating layer 1b is the value at 20°C.

[0043] The resin composition for forming the insulating layer 1b may contain various additives. Examples of the additives include those commonly used as plastic compounding chemicals, such as dispersants, tackifiers, antioxidants, antioxidants, processing aids, stabilizers, antifoaming agents, flame retardants, thickeners, and pigments.

[0044] In the base sheet 10 according to the first embodiment, the insulating layer 1b preferably has a thermal conductivity of 5 W / m·K or more, more preferably 7 W / m·K or more, and even more preferably 10 W / m·K or more. As explained above, the content of the inorganic filler in the insulating layer 1b is limited in order to ensure that the insulating layer 1b exhibits excellent adhesiveness, mechanical strength, and electrical insulation properties. Therefore, the upper limit of the thermal conductivity of the insulating layer 1b is usually 30 W / m·K.

[0045] In the original sheet 10 according to the first embodiment, the insulating layer 1b has a volume resistivity of 1×10 12 It is preferable that the volume resistivity is 1×10 Ω·cm or more. 13 It is preferable that the resistivity is Ω·cm or more. Volume resistivity is 1×10 12 When the resistivity is Ω·cm or more, the insulating layer 1b can exhibit sufficient electrical insulating properties. Since the insulating layer 1b is highly filled with the inorganic filler, it is difficult to expect excessive electrical insulation from the insulating layer 1b. Therefore, the upper limit of the volume resistivity of the insulating layer 1b is usually 1×10 18 Ω·cm.

[0046] The thickness of the insulating layer 1b is not particularly limited. The thickness of the insulating layer 1b can be set to, for example, 30 μm or more. The thickness of the insulating layer 1b may be 50 μm or more, 100 μm or more, 150 μm or more, 200 μm or more, or 250 μm or more. The thickness of the insulating layer 1b can be set to, for example, 1000 μm or less. The thickness of the insulating layer 1b may be 750 μm or less, 600 μm or less, or 450 μm or less. The thickness of the insulating layer 1b can be measured in the same manner as the thickness of the base material layer 1a described above.

[0047] The second sheet 2 is provided so as to be releasable from the insulating layer 1b. In the original sheet 10 according to the first embodiment, the separator sheet serving as the second sheet 2 can be made of any of various known resin films. Examples of the resin film include polyester resin films, polyolefin resin films, and polyimide resin films. In order to improve the peelability from the insulating layer 1b, the resin film may be subjected to a release treatment on the surface thereof that will be laminated on the insulating layer 1b.

[0048] In the original sheet 10 according to the first embodiment, the thickness of the separator sheet serving as the second sheet 2 is not particularly limited. The thickness of the separator sheet can be, for example, 25 μm or more. The thickness of the separator sheet may be 50 μm or more, or may be 75 μm or more. The thickness of the separator sheet can be, for example, 500 μm or less. The thickness of the separator sheet may be 250 μm or less, or may be 200 μm or less. The thickness of the separator sheet can be measured in the same manner as the thickness of the substrate layer 1a described above.

[0049] Second Embodiment Next, referring to Figures 2(a) and (b), we will explain an example of an original sheet according to a second embodiment of the present invention, in which the first sheet and the second sheet are both rectangular in plan view and the second sheet is the same laminated sheet as the first sheet.

[0050] As shown in Figures 2(a) and (b), the original sheet 10' of the second embodiment, like the original sheet 10 of the first embodiment, comprises a first sheet 1 which is a laminated sheet in which an insulating layer 1b is laminated on a base layer 1a, and a second sheet 2 laminated on the insulating layer 1b of the first sheet 1. In the original sheet 10' of the second embodiment, the base material layer 1a, the base material layer 2a, the insulating layer 1b, and the insulating layer 2b are configured in the same manner as described in the original sheet 10 of the first embodiment, so their description will not be repeated.

[0051] As described above, in the original sheet 10' according to the second embodiment, the second sheet 2 is the same laminated sheet as the first sheet 1, and is a laminated sheet in which an insulating layer 2b is laminated on a base material layer 2a (see Figures 2(a) and (b)). As shown in Figures 2(a) and (b), in the original sheet 10' of the second embodiment, the second sheet 2 is laminated on the insulating layer 1b of the first sheet 1 with the insulating layer 2b abutting against the insulating layer 1b of the first sheet 1. That is, the original sheet 10' according to the second embodiment is formed by stacking two laminated sheets with the insulating layers (insulating layer 1b and insulating layer 2b) in contact with each other. Therefore, in the original sheet 10' according to the second embodiment, a laminate of insulating layers (a laminate of insulating layers 1b and 2b) is sandwiched between two base layers (base layer 1a and base layer 2a).

[0052] In the original sheet 10' according to the second embodiment, the first sheet 1 and the second sheet 2 are configured in a rectangular shape with approximately the same dimensions in a plan view. As shown in Figure 2(a), in the original sheet 10' according to the second embodiment, the first sheet 1 and the second sheet 2 are stacked with a misalignment in the diagonal direction Dd (the direction indicated by the arrow in the figure).

[0053] The original sheet 10' of the second embodiment is configured as described above, so that in addition to the insulating layer 1b of the first sheet 1, the insulating layer 2b of the second sheet 2 also has an exposed portion Ex2' exposed on the outside of the first sheet 1. Specifically, in the original sheet 10' of the second embodiment, as shown in Figure 2(b), on one side in the longitudinal direction (x-axis direction), an exposed portion Ex1 of the insulating layer 1b of the first sheet 1 is provided between the first side E1a of the first sheet 1 and the first' side E2a of the second sheet 2, and on the other side in the longitudinal direction (x-axis direction), an exposed portion Ex2' of the insulating layer 2b of the second sheet 2 is provided between the second side E1b of the first sheet 1 and the second' side E2b of the second sheet 2. Furthermore, in the original sheet 10' of the second embodiment, as shown in Figure 2(c), on one side in the width direction (y-axis direction), an exposed portion Ex1 of the insulating layer 1b of the first sheet 1 is provided between the fourth side E1d of the first sheet 1 and the fourth' side E2d of the second sheet 2, and on the other side in the width direction (y-axis direction), an exposed portion Ex2' of the insulating layer 2b of the second sheet is provided between the third side E1c of the first sheet 1 and the third' side E2c of the second sheet 2.

[0054] That is, in the original sheet 10' according to the second embodiment, the exposed portions Ex1 and Ex2' are L-shaped and are provided at positions that are plane-symmetrical with respect to the diagonal direction Dd.

[0055] As with the original sheet 10 of the first embodiment, in the original sheet 10' of the second embodiment, it is preferable that the length by which the exposed portion Ex1 of the first sheet 1 extends outward beyond the second sheet 2 is up to 10 mm. The length may be 8 mm or less, 7 mm or less, or 6 mm or less. The length may be 2 mm or more, 3 mm or more, or 4 mm or more.

[0056] In the original sheet 10' according to the second embodiment, the length by which the exposed portion Ex2' of the second sheet 2 extends outward beyond the first sheet 1 is preferably 10 mm or less at most. The length may be 8 mm or less, 7 mm or less, or 6 mm or less. The length may be 2 mm or more, 3 mm or more, or 4 mm or more.

[0057] The original sheet 10 according to the first embodiment can be manufactured, for example, as follows.

[0058] First, the above-mentioned resin composition is mixed with an organic solvent to prepare a coating composition. The organic solvent used is one that can dissolve the resin contained in the resin composition, and examples of such organic solvents include methyl ethyl ketone and toluene. The coating composition can be prepared by mixing the above-mentioned resin composition and an organic solvent using a stirring device. Examples of the stirring device include a ball mill, a planetary mixer, a homogenizer, and a three-roll mill.

[0059] Next, the coating composition is applied to one surface of the base layer 1a in a desired thickness. The coating composition can be applied using a coating device. Examples of the coating device include a gravure roll coater, a reverse roll coater, a kiss roll coater, a knife coater, a comma coater, and a direct coater. When coating is carried out using the coating device as described above, the substrate layer 1a is usually wound up in a roll and loaded into the coating device.

[0060] Next, the substrate layer 1a coated with the coating composition is introduced into a drying furnace to remove the organic solvent contained in the coating composition, thereby obtaining a laminated sheet (first sheet 1) in which an insulating layer 1b is laminated on the substrate layer 1a. The organic solvent can be removed by, for example, passing the substrate layer 1a coated with the coating composition through a general heating and drying oven for a predetermined period of time.

[0061] Next, a separator sheet serving as the second sheet 2 is laminated on the insulating layer 1b of the first sheet 1 so that a portion of the insulating layer 1b of the first sheet 1 is exposed on the surface. Specifically, as shown in Figure 1(a), the third' side E2c and fourth' side E2d of the second sheet 2, which are arranged at a distance in the width direction (y-axis direction), are overlapped with the third' side E1c and fourth' side E1d of the first sheet 1, which are arranged at a distance in the width direction (y-axis direction), respectively, and the separator sheet, which is the second sheet 2, is laminated on the insulating layer 1b of the first sheet 1 so that it is misaligned with the first sheet 1 in the length direction (x-axis direction). As a result, an original sheet 10 can be obtained in which an exposed portion Ex1 is provided between the first side E1a of the first sheet 1 and the first' side E2a of the second sheet. The second sheet 2, which is a separator sheet, can be laminated on the insulating layer 1b of the first sheet 1 using any of various known sheet laminating devices.

[0062] The original sheet 10' according to the second embodiment can be manufactured, for example, as follows.

[0063] First, a set of laminated sheets is obtained in which an insulating layer is laminated on a base layer in the same manner as described in the manufacturing of the original sheet 10 according to the first embodiment. Specifically, a first sheet 1 is obtained in which an insulating layer 1b is laminated on a base material layer 1a, and a second sheet 2 is obtained in which an insulating layer 2b is laminated on a base material layer 2a.

[0064] Next, as shown in FIG. 2(a), the second sheet 2 is laminated on the first sheet 1 with the positions shifted in the diagonal direction Dd (the direction indicated by the arrow in the figure). The second sheet 2 is laminated onto the first sheet 1 so that the insulating layer 2b of the second sheet 2 abuts on the insulating layer 1b of the first sheet 1. This allows for the production of a base sheet 10' in which the exposed portion Ex1 of the L-shaped insulating layer 1b of the first sheet 1 and the exposed portion Ex2' of the L-shaped insulating layer 2b of the second sheet 2 are arranged in a location that is plane-symmetrical with respect to the diagonal direction Dd. The insulating layer 2b of the second sheet 2 can be laminated on the insulating layer 1b of the first sheet 1 using any of various known sheet laminating devices.

[0065] The above-described original plate sheet 10 according to the first embodiment and the original plate sheet 10' according to the second embodiment of the present invention are used to obtain an insulating and heat-dissipating sheet. The insulating and heat-dissipating sheet is obtained by cutting the original plate sheet 10 and the original plate sheet 10' into a predetermined shape and size using a punching press or the like using a punch and a die. Here, in order to increase the thermal conductivity of the insulating heat dissipation sheet when it is made into an insulating heat dissipation sheet, the resin composition constituting the insulating layer 1b of the original sheet 10, as well as the resin composition constituting the insulating layer 1b of the original sheet 10' and the resin composition constituting the insulating layer 2b of the original sheet 10' are usually highly filled with inorganic filler. Therefore, since the resin composition as described above is very brittle and easily crumbles, if the original plate sheet 10 and the original plate sheet 10' are cut in this state using a punching press or the like, the insulating layer 1b of the original plate sheet 10 and the insulating layer 1b and insulating layer 2b of the original plate sheet 10' may crumble during cutting, making it impossible to perform good cutting. Therefore, before cutting the original plate sheet 10 and the original plate sheet 10' using a punching press or the like, the original plate sheet 10 and the original plate sheet 10' may be compressed in the thickness direction so that the resin composition constituting the insulating layer 1b of the original plate sheet 10, and the resin composition constituting the insulating layer 1b and the resin composition constituting the insulating layer 2b of the original plate sheet 10' have sufficient hardness.

[0066] Here, in the original sheet 10 according to the first embodiment, as shown in Figures 1(a) and 1(b), an exposed portion Ex1 is provided between the first side E1a of the first sheet 1 and the first' side E2a of the second sheet. That is, in the original sheet 10 according to the first embodiment, the insulating layer 1b of the first sheet 1 is provided so as to be exposed outside the edge in the x-axis direction (length direction) of the separator sheet, which is the second sheet 2. Therefore, when the original sheet 10 is compressed in the thickness direction as shown in FIG. 3, a portion of the insulating layer 1b exposed outside the edge in the x-axis direction of the separator sheet, which is the second sheet, can be shifted in the thickness direction. This prevents a portion of the insulating layer 1b from extending beyond the edge of the base layer 1a in the x-axis direction, thereby preventing the resin composition constituting the insulating layer 1b from falling off the base sheet 10.

[0067] Furthermore, in the original sheet 10' according to the second embodiment, as shown in Figures 2(a) to 2(c), the exposed portion Ex1 of the L-shaped insulating layer 1b of the first sheet 1 and the exposed portion Ex2' of the L-shaped insulating layer 2b of the second sheet 2 are arranged in positions that are plane-symmetrical with respect to the diagonal direction Dd. That is, in the original sheet 10' of the second embodiment, the insulating layer 1b of the first sheet 1 is arranged so as to be exposed outside one edge in the x-axis direction (length direction) and y-axis direction (width direction) of the laminated sheet that is the second sheet, and the insulating layer 2b of the second sheet 2 is arranged so as to be exposed outside the other edge in the x-axis direction (length direction) and y-axis direction (width direction) of the laminated sheet that is the first sheet 1. Therefore, as shown in Figures 4(a) and 4(b), when the original plate sheet 10' is compressed in the thickness direction, a portion of the insulating layer 1b exposed outside one edge in the x-axis direction (length direction) and y-axis direction (width direction) can be shifted in the thickness direction, and further, a portion of the insulating layer 2b exposed outside the other edge in the x-axis direction (length direction) and y-axis direction (width direction) can be shifted in the thickness direction. This not only prevents a portion of the insulating layer 1b from extending beyond one edge of the base layer 1a in the x-axis and y-axis directions, but also prevents a portion of the insulating layer 2b from extending beyond the other edge of the base layer 2a in the x-axis and y-axis directions, thereby preventing the resin composition constituting the insulating layer 1b and the resin composition constituting the insulating layer 2b from falling off the base sheet 10'. That is, it is possible to prevent the resin composition constituting the laminate of the insulating layer 1b and the insulating layer 2b from falling off from the base sheet 10'.

[0068] In addition, in the original sheet 10 of the first embodiment, the portion of the insulating layer 1b exposed outside the edge in the x-axis direction (length direction) of the separator sheet, which is the second sheet 2, is not used to form an insulating heat dissipation sheet, but is discarded after at least one insulating heat dissipation sheet is cut out from the original sheet 10. Furthermore, in the original sheet 10' according to the second embodiment, the portion of the insulating layer 1b exposed outside one edge in the x-axis direction (lengthwise) and y-axis direction (widthwise) of the laminated sheet, which is the second sheet, and the portion of the insulating layer 2b exposed outside the other edge in the x-axis direction (lengthwise) and y-axis direction (widthwise) of the laminated sheet, which is the first sheet 1, are not used to form an insulating heat dissipation sheet, and are discarded after at least one insulating heat dissipation sheet has been cut out from the original sheet 10'.

[0069] The original sheet according to the present invention is not limited to the above-described embodiment. Furthermore, the original sheet according to the present invention is not limited by the above-described effects. The original sheet according to the present invention can be modified in various ways without departing from the spirit of the present invention.

[0070] In the original sheet 10 of the first embodiment described above, the second sheet 2 is made of a separator sheet, and as shown in Figure 1(a), the second sheet 2 is misaligned with the first sheet 1 in the longitudinal direction (x-axis direction) with the third' side E2c and fourth' side E2d, which are arranged at a distance in the width direction (y-axis direction), overlapping the third side E1c and fourth side E1d of the first sheet 1, which are arranged at a distance in the width direction (y-axis direction), respectively.However, the manner of misalignment when the second sheet 2 is made of a separator sheet is not limited to this. For example, even when the second sheet 2 is composed of a separator sheet, as shown in Figure 2(a), the original sheet 10 may be stacked so that the first sheet 1 and the second sheet 2 are misaligned in the diagonal direction (the direction indicated by the arrow in Figure 2(a)). Alternatively, as shown in Figure 5, the second sheet 2 may be configured as a rectangle in plan view with smaller planar dimensions than the first sheet 1, and the first sheet 1 and the second sheet 2 may be misaligned so that the insulating layer 1b is exposed outside the four sides of the second sheet 2.

[0071] In the original sheet 10' of the second embodiment described above, the second sheet 2 is composed of the same laminated sheet as the first sheet 1, and as shown in Figure 2(a), an example has been described in which the first sheet 1 and the second sheet 2 are laminated so as to be misaligned in the diagonal direction (the direction indicated by the arrow in Figure 2(a)). However, the manner of misalignment when the second sheet 2 is composed of a laminated sheet is not limited to this. For example, even when the second sheet 2 is constructed as a laminated sheet, as shown in Figure 1, the second sheet 2 may be misaligned with the first sheet 1 in the longitudinal direction (x-axis direction) with the third' side E2c and fourth' side E2d, which are arranged at a distance in the width direction (y-axis direction), overlapping the third side E1c and fourth side E1d of the first sheet 1, which are arranged at a distance in the width direction (y-axis direction), respectively.

[0072] In short, in the original sheet 10 of the first embodiment, it is sufficient that the first sheet 1 and the second sheet 2 are laminated so that at least a portion of the insulating layer 1b of the first sheet 1 is exposed, and in the original sheet 10' of the second embodiment, it is sufficient that the first sheet 1 and the second sheet 2 are laminated so that at least a portion of the insulating layer 1b of the first sheet 1 and at least a portion of the insulating layer 2b of the second sheet 2 are exposed.

[0073] Furthermore, in the above first embodiment and second embodiment, examples have been described in which the first sheet 1 and the second sheet 2 are rectangular in plan view, but the shapes of the first sheet 1 and the second sheet 2 in plan view are not limited to rectangular. The shape of the first sheet 1 and the second sheet 2 in plan view may be a polygonal shape other than a rectangle (for example, a pentagonal, hexagonal, or octagonal shape), or may be a circular or elliptical shape. [Example]

[0074] Example 1 [1st Sheet] A varnish was prepared by dispersing boron nitride particles (median diameter: 24 μm), aluminum oxide particles (median diameter: 0.9 μm), and silicon oxide particles (primary particle diameter: 0.007 μm) in an organic solvent so that the total solid content was 55% by volume of the boron nitride particles (median diameter: 24 μm), aluminum oxide particles (median diameter: 0.9 μm), and silicon oxide particles (primary particle diameter: 0.007 μm). The volume ratio of boron nitride particles to the total of boron nitride particles, aluminum oxide particles, and silicon oxide particles (BN ratio) was 50%. The varnish was applied to a PET film (substrate layer; planar dimensions: 500 mm × 500 mm, thickness: 100 μm) that had been matte-treated by sandblasting, and then dried to form a dry coating of the thermosetting resin composition on the PET film. The varnish was applied to the matte-treated side of the PET film, and the thickness of the dried coating (insulating layer) was 100 μm. In this way, a first sheet according to Example 1 was obtained. [Second Sheet] As the second sheet according to Example 1, a PET film (planar dimensions: 500 mm×500 mm, thickness: 100 μm) that had been subjected to a matte treatment by sandblasting was prepared. [Base sheet] As shown in Figures 1(a) and (b), the first sheet and the second sheet were stacked to obtain a first laminate, and then the first laminate was compressed in the thickness direction to obtain the base sheet of Example 1. The first sheet and the second sheet were overlapped so that the insulating layer of the first sheet and the matte-treated surface of the second sheet were in contact with each other. The length by which the exposed portion of the first sheet (Ex1 in FIGS. 1(a) and 1(b)) extended outward beyond the second sheet was 5 mm. Furthermore, the first laminate was compressed in the thickness direction at a temperature of 120° C. and a pressure of 5 MPa for 20 minutes.

[0075] Example 2 The base sheet of Example 2 was obtained in the same manner as Example 1, except that the length by which the exposed portion of the first sheet (Ex1 in Figures 1(a) and (b)) extended outward from the second sheet was 10 mm.

[0076] (Comparative Example 1) The base sheet for Comparative Example 1 was obtained in the same manner as Example 1, except that the length by which the exposed portion of the first sheet (Ex1 in Figures 1(a) and (b)) extended outward from the second sheet was set to 0 mm, i.e., the first sheet and the second sheet were overlapped so that there was no exposed portion.

[0077] Example 3 [1st Sheet] In the same manner as in Example 1, a first' sheet was prepared. [Second Sheet] As the second' sheet according to Example 3, a sheet in which an insulating layer was formed on a PET film similar to the first sheet in Example 1 was prepared. [Base sheet] As shown in Figures 2(a) to (c), the first' sheet and the second' sheet were stacked to obtain a second laminate, and then the second laminate was compressed in the thickness direction to obtain the base sheet of Example 3. The first' sheet and the second' sheet were overlapped so that the insulating layer of the first' sheet and the insulating layer of the second' sheet were in contact with each other. In addition, the length by which the exposed portion of the first' sheet (Ex1 in Figures 2(a) to (c)) extends outward from the second' sheet, and the length by which the exposed portion of the second' sheet (Ex2' in Figures 2(a) to (c)) extends outward from the first' sheet were both 5 mm. Furthermore, the second laminate was compressed in the thickness direction under the same conditions as in Example 1.

[0078] Example 4 The base sheet of Example 4 was obtained in the same manner as Example 3, except that the length by which the exposed portion of the first' sheet (Ex1 in Figures 2(a) to (c)) extends outward from the second' sheet and the length by which the exposed portion of the second' sheet (Ex2' in Figures 2(a) to (c)) extends outward from the first' sheet were both 10 mm.

[0079] (Comparative Example 2) The original sheet for Comparative Example 2 was obtained in the same manner as in Example 3, except that the length by which the exposed portion of the first' sheet (Ex1 in Figures 2(a) to (c)) extends outward from the second' sheet and the length by which the exposed portion of the second' sheet (Ex2' in Figures 2(a) to (c)) extends outward from the first' sheet were both set to 0 mm, i.e., the first' sheet and the second' sheet were overlapped so that there were no exposed portions.

[0080] <Protrusion amount of insulating layer from the edge of the base sheet> For the original sheet according to each example, the amount of protrusion of the insulating layer from the edge of the original sheet was measured, and the results are shown in Table 1 below. The amount of protrusion of the insulating layer from the edge of the original sheet was measured at any five points using a vernier caliper and calculated as the arithmetic average of the measured values.

[0081] [Table 1]

[0082] From Table 1 above, it was confirmed that by providing exposed portion Ex1 shown in Figures 1(a) and (b) and exposed portions Ex1 and Ex2' shown in Figures 2(a) to (c), the amount of protrusion of the insulating layer in the obtained base sheet (base sheet of Examples 1 to 4) is reduced. From this, it is considered that the base sheets of Examples 1 to 4 can prevent the resin composition that constitutes the insulating layer from falling off. [Explanation of symbols]

[0083] 1 first sheet, 2 second sheet, 10 original sheet, 10' original sheet, 1a base material layer, 1b insulating layer, 2a base material layer, 2b insulating layer, E1a 1st side, E1b 2nd side, E1c 3rd side, E1d 4th side, E2a 1st' side, E2b 2nd' side, E2c 3rd' side, E2d 4th' side, Ex1 exposed part, Ex2 exposed part, Ex2' exposed part, Dd diagonal direction.

Claims

1. A base sheet used to cut out at least one insulating and heat-dissipating sheet, a first sheet which is a laminated sheet in which an insulating layer is laminated on a base material layer; a second sheet laminated on the insulating layer of the first sheet, the insulating layer is made of a resin composition containing a resin and an inorganic filler, At least a portion of the first sheet extends outward beyond the second sheet, and the insulating layer has an exposed portion that is exposed outside the outer periphery of the second sheet. Original plate sheet.

2. The first sheet and the second sheet are both rectangular in plan view, the first sheet and the second sheet are laminated such that one side of the first sheet and one side of the second sheet are parallel to each other at a distance from each other, and the side of the second sheet is positioned more inward than the side of the first sheet; The exposed portion is provided between the two sides. The base sheet according to claim 1 .

3. The second sheet is a separator sheet provided so as to be peelable from the insulating layer. The base sheet according to claim 1 or 2.

4. the second sheet is the same laminated sheet as the first sheet, the first sheet and the second sheet are stacked with a diagonal offset, The insulating layer of the second sheet also has an exposed portion that is exposed on the outside of the first sheet. The base sheet according to claim 2 .

5. The length by which the exposed portion of the second sheet extends outward beyond the first sheet is 10 mm at most. The base sheet according to claim 4.

6. The length by which the exposed portion of the first sheet extends outward beyond the second sheet is 10 mm at most.

6. The base sheet according to claim 1, 2, 4 or 5.

7. The length by which the exposed portion of the first sheet extends outward beyond the second sheet is 10 mm at most. The base sheet according to claim 3 .

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