Manufacturing method for adhesive sheet equipped with metal sheet and adhesive sheet equipped with metal sheet

Abstract

A manufacturing method for an adhesive sheet equipped with a metal sheet according to the present invention involves cutting a laminated sheet, which comprises a metal layer configured from a metal sheet and an adhesive layer configured from a thermosetting adhesive sheet, so as to manufacture an adhesive sheet equipped with a metal sheet and comprising the metal layer and the adhesive layer, wherein: in the laminated sheet, the metal sheet has a first surface and a second surface that is reverse of the first surface, and the thermosetting adhesive sheet has a first adhesive surface and a second adhesive surface that is reverse of the first adhesive surface; the first surface of the metal sheet and the second adhesive surface of the thermosetting adhesive sheet are bonded; the thermosetting adhesive sheet is configured from an epoxy resin composition containing an epoxy resin and an inorganic filler; and, in the adhesive sheet equipped with a metal sheet, at least part of the end surface of the metal layer is configured as a tapered surface and the angle formed by the tapered surface and the second surface is an obtuse angle.

Description

METHOD FOR MANUFACTURING A METAL SHEET-ATTACHED ADHESIVE SHEET, AND METAL SHEET-ATTACHED ADHESIVE SHEET CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority from Japanese Patent Application No. 2023-209529, the contents of which are incorporated herein by reference.

[0002] The present invention relates to a method for producing a metal sheet-attached adhesive sheet, and a metal sheet-attached adhesive sheet.

[0003] Conventionally, semiconductor modules in which semiconductor elements are molded in a molding resin have been widely used. Because such semiconductor modules generate heat when power is applied, various heat dissipation measures have been implemented to prevent the junction temperature in the semiconductor module from exceeding a predetermined value. One known heat dissipation measure for a heat-generating body that requires heat dissipation, such as a semiconductor module, is a method using a metal sheet-attached adhesive sheet. In this method, the heat-generating body is used as an adherend, and a metal sheet is attached to the adherend via an adhesive sheet, allowing heat to be dissipated through the metal sheet.

[0004] Thermosetting adhesive sheets containing epoxy resins are known as such adhesive sheets because they exhibit good adhesion to various adherends and have excellent heat resistance, while thermosetting adhesive sheets made from epoxy resin compositions containing epoxy resins and inorganic fillers are known as such adhesive sheets because they exhibit good thermal conductivity from a heating element to a metal sheet.

[0005] Such metal sheet-attached adhesive sheets are produced, for example, by cutting a laminated sheet having a metal layer made of a metal sheet and an adhesive layer made of a thermosetting adhesive sheet into individual pieces. Before being completely cured, an epoxy resin composition is usually in a brittle state. Therefore, metal sheet-attached adhesive sheets have the problem that the adhesive layer easily peels off from the metal sheet.

[0006] Peeling of the adhesive layer is likely to occur when a strong bending stress is applied to the metal sheet-attached adhesive sheet, etc. Patent Document 1 below discloses that in order to make it easier to remove each metal sheet-attached adhesive sheet from a stack of multiple metal sheet-attached adhesive sheets, part or all of the outer peripheral edge of the metal sheet is made to expand outward in a direction away from the thermosetting adhesive sheet.

[0007] Japanese Patent No. 6829998

[0008] When the outer peripheral edge of the metal sheet is flared outward away from the thermosetting adhesive sheet, the edge of the metal sheet becomes acute and is likely to scratch the mating material that comes into contact with the edge. Therefore, for example, workers handling the metal sheet-attached adhesive sheet are required to handle it carefully to avoid injuring their fingertips, etc. Therefore, an object of the present invention is to provide a metal sheet-attached adhesive sheet that is easy to handle. Another object of the present invention is to provide a method for manufacturing a metal sheet-attached adhesive sheet that is easy to handle.

[0009] In order to solve the above-mentioned problems, the present invention provides a method for producing a metal sheet-attached adhesive sheet comprising a metal layer composed of a metal sheet and an adhesive layer composed of a thermosetting adhesive sheet by cutting a laminated sheet comprising the metal layer and the adhesive layer, wherein in the laminated sheet: the metal sheet has a first surface and a second surface opposite to the first surface; the thermosetting adhesive sheet has a first adhesive surface and a second adhesive surface opposite to the first adhesive surface; the first surface of the metal sheet and the second adhesive surface of the thermosetting adhesive sheet are adhered to each other; the thermosetting adhesive sheet is made of an epoxy resin composition containing an epoxy resin and an inorganic filler; and in the metal sheet-attached adhesive sheet, at least a portion of the end surface of the metal layer is a tapered surface, and the angle formed between the tapered surface and the second surface is an obtuse angle.

[0010] In order to solve the above-mentioned problems, the present invention provides a metal sheet-attached adhesive sheet comprising a metal layer made of a metal sheet and an adhesive layer made of a thermosetting adhesive sheet, wherein the metal sheet has a first surface and a second surface opposite to the first surface, the thermosetting adhesive sheet has a first adhesive surface and a second adhesive surface opposite to the first adhesive surface, the first surface of the metal sheet and the second adhesive surface of the thermosetting adhesive sheet are adhered to each other, the thermosetting adhesive sheet is made of an epoxy resin composition containing an epoxy resin and an inorganic filler, and at least a portion of the end surface of the metal layer is a tapered surface, and the angle formed between the tapered surface and the second surface is an obtuse angle.

[0011] 1A is a perspective view showing a laminated sheet used as a raw material sheet for a metal sheet-attached adhesive sheet according to one embodiment of the present invention; FIG. 1B is a cross-sectional view showing a cross section of the laminated sheet (a cross-sectional view taken along the line bb in FIG. 1A); and FIG. 1C is a cross-sectional view showing a metal sheet-attached adhesive sheet according to one embodiment of the present invention.

[0012] An embodiment of the present invention will be described below.

[0013] (Raw Material Sheet) The metal sheet-attached adhesive sheet according to this embodiment is cut out from a laminate sheet having a metal layer made of a metal sheet and an adhesive layer made of a thermosetting adhesive sheet. That is, in this embodiment, the laminate sheet is used as a raw material sheet for the metal sheet-attached adhesive sheet. Figures 1a and 1b are a perspective view and a cross-sectional view showing the state of the laminate sheet (raw material sheet S) just before the metal sheet-attached adhesive sheet is cut into individual pieces. Figure 1c is a cross-sectional view showing the cross-sectional structure of the metal sheet-attached adhesive sheet 10 after it has been cut out from the raw material sheet S.

[0014] The raw material sheet S according to this embodiment has a first surface Sx and a second surface Sy, which is the surface opposite to the first surface Sx. The raw material sheet S according to this embodiment has a rectangular shape in plan view. All four corners of the rectangle are right angles. The raw material sheet S has a first direction (hereinafter also referred to as the longitudinal direction D1) parallel to two of the four sides defining the rectangle, and a second direction (hereinafter also referred to as the transverse direction D2) parallel to the remaining two sides. In the raw material sheet S according to this embodiment, the first direction and the second direction are orthogonal. The raw material sheet S further has a third direction (hereinafter also referred to as the thickness direction D3) perpendicular to each of the first direction and the second direction.

[0015] The raw material sheet S according to this embodiment is a laminated sheet including a metal layer 1 made of a metal sheet Sa and an adhesive layer 2 made of a thermosetting adhesive sheet Sb. The metal sheet Sa according to this embodiment has a first surface 1a and a second surface 1b opposite to the first surface 1a. The first surface 1a of the metal sheet Sa is located on the side of the first surface Sx of the raw material sheet S. The second surface 1b of the metal sheet Sa is located on the side of the second surface Sy of the raw material sheet S.

[0016] The thermosetting adhesive sheet Sb according to this embodiment is made of an epoxy resin composition containing an epoxy resin and an inorganic filler. The thermosetting adhesive sheet Sb according to this embodiment has a first adhesive surface 2a and a second adhesive surface 2b opposite the first adhesive surface 2a. The first adhesive surface 2a of the thermosetting adhesive sheet Sb is located on the first surface Sx side of the raw material sheet S. The second adhesive surface 2b of the thermosetting adhesive sheet Sb is located on the second surface Sy side of the raw material sheet S.

[0017] The raw material sheet S (laminate sheet) according to this embodiment has the first surface 1a of the metal sheet Sa and the second adhesive surface 2b of the thermosetting adhesive sheet Sb bonded together. The raw material sheet S according to this embodiment includes a protective sheet Sc detachably bonded to the second surface 1b of the metal sheet Sa. In the raw material sheet S according to this embodiment, the first adhesive surface 2a of the thermosetting adhesive sheet Sb is the adhesive surface used for bonding to an adherend. Therefore, the raw material sheet S according to this embodiment further includes a separator sheet Sd bonded to the first adhesive surface 2a of the thermosetting adhesive sheet Sb to protect the first adhesive surface 2a. That is, the raw material sheet S according to this embodiment has a four-layer structure.

[0018] In the raw material sheet S according to this embodiment, the metal sheet Sa and the protective sheet Sc are stacked with their outer peripheral edges aligned, and the thermosetting adhesive sheet Sb and the separator sheet Sd are stacked with their outer peripheral edges aligned. In the raw material sheet S according to this embodiment, the thermosetting adhesive sheet Sb is one size smaller than the metal sheet Sa. Therefore, in the raw material sheet S according to this embodiment, the first surface Sx is one size smaller than the second surface Sy. In the raw material sheet S according to this embodiment, the metal sheet Sa extends outward beyond the thermosetting adhesive sheet Sb. The raw material sheet S is not limited to this embodiment. In the raw material sheet S, the metal sheet Sa and the thermosetting adhesive sheet Sb may be the same size and stacked with their outer peripheral edges aligned.

[0019] The raw material sheet S is larger than the metal sheet-attached adhesive sheet 10. The raw material sheet S has a size that allows multiple metal sheet-attached adhesive sheets 10 to be cut out. In this embodiment, the metal sheet-attached adhesive sheet 10 has a rectangular shape. Like the raw material sheet S, the metal sheet-attached adhesive sheet 10 has four right-angled corners. In this embodiment, the metal sheet-attached adhesive sheet 10 is cut out from the raw material sheet S so that each side of the rectangle is parallel to each side of the raw material sheet S.

[0020] The raw material sheet S is large enough to allow multiple metal sheet-attached adhesive sheets 10 to be arranged side by side in either the longitudinal direction D1 or the transverse direction D2. The raw material sheet S of this embodiment is large enough to allow multiple metal sheet-attached adhesive sheets 10 to be arranged both vertically and horizontally. In other words, the raw material sheet S of this embodiment is at least four times (2 x 2) the size of the metal sheet-attached adhesive sheet 10.

[0021] In this embodiment, a V-groove is formed in the raw material sheet S, and the raw material sheet S is cut along the V-groove to individualize the metal sheet-attached adhesive sheet 10. The raw material sheet S has a product region S' that is used for the metal sheet-attached adhesive sheet 10, and a non-product region S" that is not used for producing the metal sheet-attached adhesive sheet 10. In this embodiment, the raw material sheet S has a product region S' that is one size smaller than the raw material sheet S. The raw material sheet S of this embodiment has a rectangular shape that is one size smaller than the thermosetting adhesive sheet Sb. The non-product region S" in this embodiment is arranged to surround the product region S'. In other words, the non-product region S" in this embodiment is in the shape of a rectangular frame that forms the outer periphery of the raw material sheet S.

[0022] The raw material sheet S of this embodiment is used to form a metal sheet-attached adhesive sheet 10 having a specific shape. The metal sheet-attached adhesive sheet 10 produced using the raw material sheet S has at least a portion of the end surface of the metal layer 1 formed as a tapered surface. The angle θ1 between the tapered surface and the second surface 1b is an obtuse angle.

[0023] In this embodiment, the product region S' is divided into a plurality of segments using a disc cutter, and the segments are used as the metal sheet-attached adhesive sheet 10. The disc cutter has a cutting edge that tapers radially outward when viewed in a direction perpendicular to the axis. That is, the disc cutter in this embodiment is designed to form a groove (V-groove) with a V-shaped cross section in the mating material when the cutting edge is brought into contact with the mating material while rotating.

[0024] The raw material sheet S in the state before the product area S' is divided into individual pieces has V-shaped grooves formed by a disc cutter on both the first surface Sx, which is the side on which the thermosetting adhesive sheet Sb is provided, and the second surface Sy, which is the opposite side of the first surface, in the metal sheet Sa and the thermosetting adhesive sheet Sb.

[0025] The raw material sheet S has first-surface V-grooves V1 provided on the first surface side and second-surface V-grooves V2 provided on the second surface side. The first-surface V-grooves V1 include a plurality of vertical grooves V11 extending in the longitudinal direction D1 and a plurality of horizontal grooves V12 extending in the horizontal direction. The second-surface V-grooves V2 are similar in that they have a plurality of vertical grooves and a plurality of horizontal grooves.

[0026] The plurality of longitudinal grooves V11 are arranged parallel to one another at a predetermined distance in the lateral direction D2, and the plurality of lateral grooves V12 are arranged parallel to one another at a predetermined distance in the longitudinal direction D1.

[0027] The first surface V groove V1 and the second surface V groove V2 are longitudinal grooves that are in the same position. The first surface V groove V1 and the second surface V groove V2 are lateral grooves that are in the same position.

[0028] The first-surface V-groove V1 and the second-surface V-groove V2 may be connected at the deepest part of the groove, or may be separated. When the first-surface V-groove V1 and the second-surface V-groove V2 are connected, the metal sheet-attached adhesive sheet 10 can be immediately harvested from the raw material sheet S. When the first-surface V-groove V1 and the second-surface V-groove V2 are separated, adjacent metal sheet-attached adhesive sheets are connected at the center in the thickness direction D3. This allows multiple metal sheet-attached adhesive sheets to be handled as if they were a single sheet. Note that when the metal sheet-attached adhesive sheets are connected to each other, the metal sheet-attached adhesive sheets can be separated into individual pieces by breaking the connected portion.

[0029] When adjacent metal sheet-attached adhesive sheets are joined together, they may be joined by metal layer 1 or adhesive layer 2. Joining them by metal layer 1 poses the problem of increased likelihood of burrs being generated upon breaking. However, joining them by adhesive layer 2 reduces the likelihood of such a problem occurring, making it easier to obtain a metal sheet-attached adhesive sheet 10 that is less likely to damage the mating material that contacts the edge surface. On the other hand, joining them by metal layer 1 makes it less likely that dust and other particles will be generated upon breaking. If the metal sheet-attached adhesive sheets are left joined by adhesive layer 2, and adhesive layer 2 is heated and softened somewhat upon breaking, dust generation can be prevented.

[0030] The raw material sheet S may be connected in one of the longitudinal grooves and the transverse grooves, while the metal sheet-attached adhesive sheet 10 may be separated in the other. In this case, the V-groove in one of the longitudinal grooves and the transverse grooves may be the second-side V-groove V2 only. That is, in one of the longitudinal grooves and the transverse grooves, the second-side V-groove V2 may reach close to the first adhesive surface 2a of the thermosetting adhesive sheet Sb, and the first-side V-groove V1 may be the other V-groove only. If the raw material sheet S has the separator sheet Sd, the second-side V-groove V2 in one of the longitudinal grooves and the transverse grooves may reach partway through the separator sheet Sd so as not to completely cut the separator sheet Sd. In this case, the separator sheet Sd is connected in either the longitudinal direction D1 or the transverse direction D2, preventing the metal sheet-attached adhesive sheet 10 from coming apart. Conversely, one of the vertical grooves and the horizontal grooves may be the first-surface-side V-groove V1 only. In this case, the first-surface-side V-groove V1 may extend to a position close to the second surface 1b of the metal sheet Sa, or may extend partway through the protective sheet Sc. In this case, the metal sheet-attached adhesive sheet 10 can also be prevented from coming apart.

[0031] In either of the above cases, a metal sheet-attached adhesive sheet 10 can be obtained having tapered surfaces on two opposing sides of the rectangle, with the angle θ1 formed with the second surface 1b being an obtuse angle. In this case, as shown in FIG. 1c, the tapered surface IS1, which connects to the edge of the second surface 1b at the corner 10c, is formed so as to diverge outward from the second surface 1b toward the first surface 1a, and the tapered surface IS1 is also formed so as to diverge outward from both ends of the second surface 1b. This makes it easy to scoop up the metal sheet-attached adhesive sheet 10 using a pair of members X equipped with claws that can abut the tapered surface IS1 from the sides. This makes it easy to pick up individual metal sheet-attached adhesive sheets 10 from multiple metal sheet-attached adhesive sheets 10 stacked in the thickness direction. In this embodiment, the tapered surface IS1 makes it easy to pick up individual metal sheet-attached adhesive sheets 10, and therefore, interfacial peeling between the metal layer 1 and the adhesive layer 2 is less likely to occur when handling the metal sheet-attached adhesive sheet 10.

[0032] The tapered surface IS1 makes it easy to remove the metal sheet-attached adhesive sheet 10 of this embodiment from a workbench, even when the second surface 1b of the metal sheet Sa is placed directly against the top surface of the workbench. The central portion of the metal sheet-attached adhesive sheet 10 in the thickness direction protrudes outward, making it easy to remove from the workbench not only when the metal sheet Sa is placed face down, but also when the metal sheet Sa is placed face up. As described above, the raw material sheet S of this embodiment can be advantageous for forming an easy-to-handle metal sheet-attached adhesive sheet 10.

[0033] The metal sheet Sa constituting the metal layer 1 in the raw material sheet S can be a sheet made of a metal such as copper, aluminum, iron, nickel, tin, magnesium, gold, or silver, or an alloy based on such a metal. The metal sheet Sa may also be a clad material having multiple metal layers.

[0034] The thickness of the metal sheet Sa is not particularly limited. The thickness of the metal sheet Sa may be, for example, 0.1 mm or more. The thickness of the metal sheet Sa may be 0.2 mm or more, 0.3 mm or more, or 0.4 mm or more. The thickness of the metal sheet Sa may be 0.5 mm or more, or 0.8 mm or more. The thickness of the metal sheet Sa may be, for example, 10 mm or less. The thickness of the metal sheet Sa may be 8 mm or less, 6 mm or less, or 4 mm or less. The thickness of the metal sheet Sa may be 3 mm or less, or 2 mm or less.

[0035] The metal sheet Sa may be subjected to a surface treatment such as plating, oxidation, matte finish, hairline finish, or rust prevention (antioxidation treatment) on either or both of the first surface 1a and the second surface 1b. The metal sheet Sa of this embodiment is preferably a copper plate or an aluminum plate, as they have excellent thermal conductivity. The copper plate may be subjected to an oxidation treatment such as blackening, or may be subjected to a matte finish (roughening treatment) such as blasting. The aluminum plate may be subjected to an anodizing treatment such as phosphate anodizing or sulfate anodizing, or may be subjected to a sealing treatment.

[0036] In this embodiment, since interfacial peeling between the metal layer 1 and the adhesive layer 2 is suppressed, the metal sheet Sa does not need to be subjected to any particular surface treatment. In this embodiment, an untreated rolled material such as copper or aluminum (rolled copper plate or rolled aluminum plate) that has not been subjected to any surface treatment can be used as the metal sheet Sa. Such a metal sheet Sa is preferable because it is inexpensive and available.

[0037] In this embodiment, the epoxy resin contained in the epoxy resin composition is not particularly limited. Examples of the epoxy resin contained in the epoxy resin composition include various known epoxy resins, such as triphenylmethane epoxy resins, cresol novolac epoxy resins, biphenyl epoxy resins, modified bisphenol A epoxy resins, bisphenol A epoxy resins, bisphenol F epoxy resins, modified bisphenol F epoxy resins, dicyclopentadiene epoxy resins, phenol novolac epoxy resins, and phenoxy resins. These epoxy resins may be used alone or in combination of two or more. Among these, triphenylmethane epoxy resins are preferred as the epoxy resin contained in the epoxy resin composition, and it is more preferred that 80% by mass or more of the epoxy resins contained in the thermosetting adhesive sheet be triphenylmethane epoxy resins.

[0038] The content of the epoxy resin relative to 100 parts by mass of the epoxy resin composition is preferably 5 parts by mass or more and 25 parts by mass or less, more preferably 10 parts by mass or more and 25 parts by mass or less, and even more preferably 15 parts by mass or more and 20 parts by mass or less.

[0039] The epoxy resin composition may contain a curing agent. Examples of the curing agent include phenol-based curing agents, amine-based curing agents, and acid anhydride-based curing agents. Examples of the phenol-based curing agents include phenol novolac resins, aralkyl phenol resins, dicyclopentadiene-modified phenol resins, naphthalene phenol resins, and bisphenol-based phenol resins. Examples of the amine-based curing agents include diaminodiphenyl sulfone, dicyandiamide, diaminodiphenylmethane, and triethylenetetramine. Among these, the phenol-based curing agents are preferred as the curing agent contained in the epoxy resin composition, and among the phenol-based curing agents, the aralkyl phenol resins are more preferred. Examples of the aralkoxy phenol resins include xylylene novolac phenols and bisphenol novolac phenols.

[0040] The content of the curing agent relative to 100 parts by mass of the epoxy resin composition is preferably 4 parts by mass or more and 25 parts by mass or less, more preferably 7 parts by mass or more and 20 parts by mass or less, and even more preferably 10 parts by mass or more and 15 parts by mass or less.

[0041] The epoxy resin composition may contain a curing accelerator. From the viewpoint of storage stability, it is preferable to use an imidazole-based curing accelerator, an amine-based curing accelerator, or the like as the curing accelerator. Examples of the amine-based curing accelerator include triphenyl phosphate (TPP) and boron trifluoride monoethylamine.

[0042] The content of the curing accelerator relative to 100 parts by mass of the epoxy resin composition is preferably 0.10 parts by mass or more and 0.40 parts by mass or less, more preferably 0.15 parts by mass or more and 0.35 parts by mass or less, and even more preferably 0.20 parts by mass or more and 0.30 parts by mass or less.

[0043] Examples of the inorganic filler contained in the epoxy resin composition include inorganic nitride fillers, inorganic oxide fillers, diamond, talc, clay, and calcium carbonate. Examples of the inorganic nitride fillers include boron nitride, aluminum nitride, and silicon nitride. Examples of the inorganic oxide fillers include silicon oxide (silica), aluminum oxide (alumina), titanium oxide (titania), and zirconium oxide (zirconia). Among these, the inorganic filler contained in the epoxy resin composition is preferably at least one selected from the group consisting of boron nitride, aluminum oxide, and silicon oxide. Furthermore, the epoxy resin composition more preferably contains, as the inorganic filler, a mixture containing boron nitride and aluminum oxide, or a mixture containing boron nitride and silicon oxide. The boron nitride content in the mixture is preferably 50% by mass or more and 95% by mass or less.

[0044] Because the inorganic filler has a higher thermal conductivity than epoxy resin, highly loading the thermosetting adhesive sheet Sb is advantageous in providing excellent thermal conductivity to the metal sheet-attached adhesive sheet 10. When the thermosetting adhesive sheet Sb contains boron nitride as the inorganic filler, the boron nitride content in the thermosetting adhesive sheet is preferably 30% by volume or more, more preferably 40% by volume or more, and even more preferably 50% by volume or more. By providing a boron nitride content of 30% by volume or more in the thermosetting adhesive sheet, the thermosetting adhesive sheet Sb has excellent thermal conductivity. On the other hand, from the viewpoint of providing the thermosetting adhesive sheet Sb with excellent adhesion, mechanical strength, and electrical insulation, the boron nitride content in the thermosetting adhesive sheet is preferably 65% ​​by volume or less. Note that the boron nitride content in the thermosetting adhesive sheet Sb refers to the value at 20°C.

[0045] The thermosetting adhesive sheet 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. The content of the inorganic filler in the thermosetting adhesive sheet is limited in order to ensure excellent adhesiveness and mechanical strength. Therefore, the thermal conductivity of the thermosetting adhesive sheet is typically 20 W / m K or less.

[0046] The thermosetting adhesive sheet is 1×10 １２ It is preferable that the thermosetting sheet has a volume resistivity of 1×10 Ω·cm or more. １３ It is preferable that the thermosetting adhesive sheet has a volume resistivity of Ω cm or more to exhibit sufficient electrical insulation. Note that, since the thermosetting adhesive sheet is highly filled with inorganic filler, it is difficult to expect the thermosetting adhesive sheet to have excessive electrical insulation. Therefore, the volume resistivity of the thermosetting adhesive sheet is usually 1×10 １８ It is Ω·cm or less.

[0047] The epoxy resin composition may contain various additives, such as dispersants, tackifiers, antioxidants, antioxidants, processing aids, stabilizers, antifoaming agents, flame retardants, thickeners, and pigments, which are commonly used as plastic compounding agents.

[0048] In the raw material sheet S of this embodiment, the thickness of the adhesive layer 2 formed by the thermosetting adhesive sheet Sb is not particularly limited. The thickness of the adhesive layer 2 can be, for example, 100 μm or more. The thickness of the adhesive layer 2 may be 150 μm or more, 200 μm or more, or 250 μm or more. The thickness of the adhesive layer 2 can be, for example, 1000 μm or less. The thickness of the adhesive layer 2 may be 750 μm or less, 600 μm or less, or 450 μm or less.

[0049] The protective sheet Sc can be, for example, an adhesive sheet with a base material such as polyvinyl chloride resin film, polyethylene resin film, or polyethylene terephthalate resin film. That is, the protective sheet Sc may be an adhesive sheet having a base layer and an adhesive layer. The protective sheet Sc preferably has flexibility so as to exhibit excellent conformability to the second surface 1b of the metal sheet Sa. The protective sheet Sc may remain adhered to the metal sheet Sa without being peeled off when forming a V-groove in the metal sheet Sa. In order to exhibit good grinding properties during this process, it is desirable for the protective sheet Sc to have appropriate rigidity. From this perspective, the protective sheet Sc is preferably an adhesive sheet with a base material such as polyethylene resin film.

[0050] The thickness of the polyethylene resin film is not particularly limited. The thickness of the polyethylene resin film may be, for example, 10 μm or more. The thickness of the polyethylene resin film may be 20 μm or more, or may be 30 μm or more. The thickness of the polyethylene resin film may be, for example, 200 μm or less. The thickness of the polyethylene resin film may be 150 μm or less, or may be 100 μm or less.

[0051] The separator sheet Sd may be an adhesive sheet having an adhesive layer, like the protective sheet Sc. The separator sheet Sd is preferably a simple resin sheet having no adhesive layer, in order to prevent excessive adhesion between the separator sheet Sd and the adhesive layer 2. The separator sheet Sd may be, for example, a polyvinyl chloride resin film, a polyethylene resin film, or a polyethylene terephthalate resin film. The separator sheet Sd may be, for example, kraft paper that has been subjected to a release treatment.

[0052] The separator sheet Sd is preferably a polyethylene terephthalate resin film having a matte finish applied to the surface in contact with the adhesive layer 2, in order to exhibit appropriate adhesion to the adhesive layer 2 and good easy peelability.

[0053] The thickness of the polyethylene terephthalate resin film is not particularly limited. The thickness of the polyethylene terephthalate resin film can be, for example, 25 μm or more. The thickness of the polyethylene terephthalate resin film may be 50 μm or more, or 75 μm or more. The thickness of the polyethylene terephthalate resin film can be, for example, 500 μm or less. The thickness of the polyethylene terephthalate resin film may be 250 μm or less, or 200 μm or less.

[0054] The thicknesses of the metal sheet Sa constituting the metal layer 1, the thermosetting adhesive sheet Sb constituting the adhesive layer 2, the substrate of the protective sheet Sc, and the separator sheet Sd can be measured using a micrometer or the like, and can be calculated as the arithmetic average value when the thicknesses are measured at 10 randomly selected locations.

[0055] The raw material sheet S may have a two-layer structure of a metal sheet Sa and a thermosetting adhesive sheet Sb. The raw material sheet S may have a three-layer structure or a four-layer structure. That is, the raw material sheet S may further include at least one of the protective sheet Sc and the separator sheet Sd in addition to the two-layer structure of the metal sheet Sa and the thermosetting adhesive sheet Sb.

[0056] (Metal Sheet-Attached Adhesive Sheet) The metal sheet-attached adhesive sheet 10 according to this embodiment has the same configuration and thickness of each part as the material sheet S, and therefore detailed description thereof will not be repeated here.

[0057] In the metal sheet-attached adhesive sheet 10 according to this embodiment, a part or all of the end faces defining the outer periphery of the metal layer 1 are formed into a first tapered surface I that expands outward from the second surface 1b toward the first surface 1a. Ｓ１In the metal sheet-attached adhesive sheet 10 according to this embodiment, the portion of the end surface close to the second surface 1b is a first tapered surface I. Ｓ１ It is as follows.

[0058] In the metal sheet-attached adhesive sheet 10 according to this embodiment, the metal sheet 10 is expanded outward from the first surface 1a to the second surface 1b, and the first tapered surface I Ｓ１ The second tapered surface I intersects with Ｓ２ In the metal sheet-attached adhesive sheet 10 according to this embodiment, the portion of the end face close to the first surface 1a is a second tapered surface I. Ｓ２ It is as follows.

[0059] In the metal sheet-attached adhesive sheet 10 according to this embodiment, the second surface 1b and the first tapered surface I Ｓ１ The angle θ1 between the first tapered surface I and the second tapered surface I is an obtuse angle. Ｓ１ The first tapered surface I is preferably provided on all four sides of the metal sheet-attached adhesive sheet 10, and is preferably provided on at least two opposing sides. Ｓ１ When the first tapered surface I is provided at a plurality of locations, Ｓ１ The angles formed by the first surface 1b and the second surface 1b may all be the same or different. The angle θ1 may be, for example, 95 degrees or greater. The angle θ1 may be 100 degrees or greater, or 105 degrees or greater. The angle θ1 may be 150 degrees or less. The angle θ1 may be 140 degrees or less, or 135 degrees or less.

[0060] In the metal sheet-attached adhesive sheet 10 according to this embodiment, the first surface 1a and the second tapered surface I Ｓ２ The angle θ2 between the second tapered surface I and the second tapered surface I is an obtuse angle. Ｓ２ The second tapered surface I is preferably provided on all four sides of the metal sheet-attached adhesive sheet 10, and is preferably provided on at least two opposing sides. Ｓ２ When the second tapered surface I is provided at a plurality of locations, Ｓ２and the first surface 1a may all form the same angle or different angles. The angle θ2 may be, for example, 95 degrees or greater. The angle θ2 may be 100 degrees or greater, or 105 degrees or greater. The angle θ2 may be 150 degrees or less. The angle θ2 may be 140 degrees or less, or 135 degrees or less.

[0061] In the metal sheet-attached adhesive sheet 10 according to this embodiment, a first tapered surface I is formed at the center in the thickness direction. Ｓ１ and second tapered surface I Ｓ２ In this embodiment, the interior angle α of this intersection is also an obtuse angle.

[0062] The interior angle α of the intersection is usually Ｓ１ The angle θ1 between the first surface 1a and the second tapered surface I is the supplementary angle (180-θ1). Ｓ２ and the complementary angle (180-θ2) of the angle θ2 between them is the sum (360-(θ1+θ2)). Therefore, in order to make the interior angle α of the intersection an obtuse angle, it is preferable to satisfy the following formula (1a), more preferably to satisfy the following formula (1b), and even more preferably to satisfy the following formula (1c): 190≦(θ1+θ2)<270 (1a) 190≦(θ1+θ2)≦265 (1b) 200≦(θ1+θ2)≦260 (1c)

[0063] These angles (θ1, θ2, α) can be measured by observing, with a microscope or the like, a cross section of the metal sheet-attached adhesive sheet 10 cut along a plane parallel to the thickness direction of the metal sheet-attached adhesive sheet 10 and perpendicular to the side on which the angles are to be observed. Ｓ１ , and second tapered surface I Ｓ２ If each of the above is not observed as a straight line but has some waviness, the respective angles can be determined by finding an approximate straight line using the least squares method. Each angle can also be the arithmetic mean value of measurements taken at multiple randomly selected cross sections (e.g., 10 locations).

[0064] (Method for manufacturing a metal sheet-attached adhesive sheet) In the method for manufacturing a metal sheet-attached adhesive sheet according to this embodiment, as described above, a laminated sheet including a metal layer 1 made of a metal sheet Sa and an adhesive layer 2 made of a thermosetting adhesive sheet Sb is used as the raw material sheet S. In the manufacturing method according to this embodiment, the raw material sheet S is cut to produce a metal sheet-attached adhesive sheet 10 including the metal layer 1 and the adhesive layer 2. In this embodiment, the thermosetting adhesive sheet Sb is made of an epoxy resin composition containing an epoxy resin and an inorganic filler, and has a first adhesive surface 2a and a second adhesive surface 2b opposite to the first adhesive surface 2a, and the metal sheet Sa has a first surface 1a and a second surface 1b opposite to the first surface 1a. In this embodiment, a raw material sheet S (laminated sheet) in which the first surface 1a of the metal sheet Sa and the second adhesive surface 2b of the thermosetting adhesive sheet Sb are bonded is used to produce a metal sheet-attached adhesive sheet 10 in which at least a portion of the end surface of the metal layer 1 is a tapered surface and the angle θ1 between the tapered surface and the second surface 1b is an obtuse angle.

[0065] In the manufacturing method of this embodiment, as described above, a disc cutter is used to cut the raw material sheet S. The disc cutter is usually disk-shaped and has a cutting edge on its outer periphery. The disc cutter has an axis that extends in a direction perpendicular to the plate surface and passes through the center of the disc cutter. The disc cutter is designed to make incisions in the mating material with the cutting edge by abutting the outer periphery against the mating material while rotating around the axis.

[0066] In this embodiment, the cutting means for the raw material sheet S is not limited to a disk cutter. A band saw, a laser cutter, or the like can also be used to cut the raw material sheet S. If necessary, a shearing cutter or the like may also be used to cut the raw material sheet S. In this embodiment, the raw material sheet S may be cut with a shearing cutter or the like to produce a metal sheet-attached adhesive sheet with an end face perpendicular to the second surface 1b, and then the end face may be cut obliquely to form a tapered surface.

[0067] The disc cutter has a cutting edge that tapers radially outward when viewed in a direction perpendicular to the axis. When a V-groove is formed in the raw material sheet S using such a disc cutter, it is possible to form a tapered surface on each of the inner wall surfaces rising from the deepest part of the groove. Therefore, when a shearing cutter or the like is used, cutting and forming the tapered surface are separated into two steps, whereas when a disc cutter is used, even the formation of the tapered surface is performed in one step. By cutting the raw material sheet S from the side of the metal layer 1 with the disc cutter and forming a V-groove in the raw material sheet S, the first tapered surface I is formed. Ｓ１ It can be said that the method for forming the

[0068] In terms of producing an adhesive sheet 10 with a metal sheet that is easy to handle, the shape of the adhesive sheet 10 with a metal sheet to be produced may be rectangular, and the tapered surfaces may be formed on at least two of the four sides of the rectangle, and the tapered surfaces may be formed on two opposing sides of the rectangle.

[0069] In the manufacturing method of this embodiment, a V-groove is formed with a disc cutter on both the first surface Sx of the raw material sheet S and the second surface Sy, which is the surface opposite to the first surface Sx. That is, in the manufacturing method of this embodiment, the first-surface-side V-groove V1 provided on the first surface Sx side and the second-surface-side V-groove V2 provided on the second surface Sy side are formed along a line segment that defines at least a portion of the outer periphery of the metal sheet-attached adhesive sheet 10, and the second-surface-side V-groove V2 forms the first tapered surface I. Ｓ１ The first tapered surface I is formed by the first surface V groove V1. Ｓ１ The second tapered surface I is an inverse tapered surface. Ｓ２ may be formed on the first surface Sx of the raw material sheet S, and the central portion in the thickness direction may protrude outward at the location corresponding to the line segment, thereby producing a metal sheet-attached adhesive sheet 10. In this case, an easy-to-handle metal sheet-attached adhesive sheet 10 can be efficiently produced.

[0070] When forming the V-groove along the line, the first-surface V-groove V1 may be formed after the second-surface V-groove V2. When forming the V-groove from the metal layer side, peeling of the adhesive layer 2 may occur near the V-groove. However, by forming the first-surface V-groove V1 from the adhesive layer side later, it becomes easier to remove the peeled portion. If peeling of the adhesive layer occurs during the formation of the second-surface V-groove V2, the peeling occurs mainly near the deepest part of the second-surface V-groove V2.

[0071] The area where peeling has occurred appears whiter than the surrounding area on the first adhesive surface 2a. Therefore, if peeling of the adhesive layer 2 occurs near the deepest portion of the second-side V-groove V2, it appears as a white line on the first adhesive surface 2a, and the extent of peeling can be determined by the width of the white line. Therefore, for example, if almost no peeling is observed, the raw material sheet S can be cut by inserting the disc cutter to a depth sufficient to reach the deepest portion of the second-side V-groove V2 when forming the first-side V-groove V1. If some peeling occurs during the formation of the second-side V-groove V2, the peeled area can be selectively removed by inserting the disc cutter to a depth sufficient to reach the deepest portion of the second-side V-groove V2 when forming the first-side V-groove V1.

[0072] The second-surface-side V-groove V2 may be provided so that its deepest portion is located in the metal layer 1 or in the adhesive layer 2. The second-surface-side V-groove V2 may be provided so that its deepest portion passes through the adhesive layer 2 and reaches the separator sheet Sd. Note that providing the first-surface-side V-groove V1 later is also effective in removing burrs that may occur on the edge of the first surface 1a of the metal layer 1.

[0073] The V-groove formed in the raw material sheet S using a disc cutter typically has a groove width that is perpendicular to the direction in which the V-groove extends, tapering from the surface of the raw material sheet S toward the deepest part of the groove. The degree to which the groove width tapers toward the deepest part is typically determined by the shape of the cutting edge of the disc cutter. Therefore, in this embodiment, multiple disc cutters with different cutting edge angles may be used to form V-grooves with different cross-sectional shapes.

[0074] The disc cutter in this embodiment may be a type similar to a tip saw or a type similar to a disc grinder. In this embodiment, a plurality of disc cutters including one or more tip saws and one or more disc grinders may be used to cut the raw material sheet S. When forming a plurality of V grooves parallel to each other in the raw material sheet S, one V groove may be formed one by one using a single disc cutter, or a plurality of V grooves may be formed at once using a plurality of disc cutters.

[0075] The metal sheet-attached adhesive sheet 10, which has been singulated by forming V-grooves on both sides of the raw material sheet S, has foreign matter adhering to its edge removed, and then the protective sheet Sc and separator sheet Sd are removed to expose the first adhesive surface 2a, which can be adhered to an adherend and used to dissipate heat from the adherend. Adhesion to the adherend can be achieved by heating the adhesive layer to a temperature equal to or higher than the curing temperature of the epoxy resin and pressing the first adhesive surface 2a against the adherend.

[0076] It should be noted that the method for manufacturing a metal sheet-attached adhesive sheet and the metal sheet-attached adhesive sheet according to the present invention are not limited to the above-described embodiments. Furthermore, the method for manufacturing a metal sheet-attached adhesive sheet and the metal sheet-attached adhesive sheet according to the present invention are not limited by the above-described effects. The method for manufacturing a metal sheet-attached adhesive sheet and the metal sheet-attached adhesive sheet according to the present invention can be modified in various ways without departing from the gist of the present invention.

[0077] The above embodiments include the following disclosures.

[0078] [1] A method for producing a metal sheet-attached adhesive sheet comprising: cutting a laminated sheet having a metal layer made of a metal sheet and an adhesive layer made of a thermosetting adhesive sheet; and producing a metal sheet-attached adhesive sheet comprising the metal layer and the adhesive layer, wherein in the laminated sheet: the metal sheet has a first surface and a second surface opposite to the first surface; the thermosetting adhesive sheet has a first adhesive surface and a second adhesive surface opposite to the first adhesive surface; the first surface of the metal sheet and the second adhesive surface of the thermosetting adhesive sheet are adhered to each other; the thermosetting adhesive sheet is made of an epoxy resin composition containing an epoxy resin and an inorganic filler; and the metal sheet-attached adhesive sheet has at least a portion of an end surface of the metal layer that is a tapered surface, and the tapered surface forms an obtuse angle with the second surface.

[0079] According to this configuration, at least a portion of the end face of the metal layer is tapered, and the angle between the tapered surface and the second surface is obtuse, which makes it less likely to damage the mating material that contacts the metal layer. This makes it possible to provide a method for manufacturing a metal sheet-attached adhesive sheet that is easy to handle.

[0080] [2] The method for manufacturing a metal sheet-attached adhesive sheet according to [1], wherein the metal sheet-attached adhesive sheet has a rectangular shape, and the tapered surfaces are formed on two opposing sides of the rectangle.

[0081] [3] The method for manufacturing a metal sheet-attached adhesive sheet according to [1] or [2], wherein the tapered surface is formed by cutting the laminated sheet from the metal layer side with a disc cutter to form a V-groove in the laminated sheet.

[0082] [4] A method for manufacturing a metal sheet-attached adhesive sheet according to [3], wherein a V-groove including a first-surface-side V-groove and a second-surface-side V-groove is formed using a disc cutter on each of a first surface of a laminate sheet and a second surface opposite to the first surface, along a line that defines at least a portion of the outer periphery of the metal sheet-attached adhesive sheet, the tapered surface being formed by the second-surface-side V-groove, and a tapered surface on the first surface of the laminate sheet being reverse-tapered to the tapered surface being formed by the first-surface-side V-groove, and the metal sheet-attached adhesive sheet has a central portion in the thickness direction that protrudes outward at a location corresponding to the line.

[0083] [5] The method for manufacturing a metal sheet-attached adhesive sheet according to claim [4], wherein, in forming the V-groove along the line, the V-groove on the first surface side is formed after the V-groove on the second surface side is formed.

[0084] [6] A metal sheet-attached adhesive sheet comprising a metal layer made of a metal sheet and an adhesive layer made of a thermosetting adhesive sheet, wherein the metal sheet has a first surface and a second surface opposite to the first surface, the thermosetting adhesive sheet has a first adhesive surface and a second adhesive surface opposite to the first adhesive surface, the first surface of the metal sheet and the second adhesive surface of the thermosetting adhesive sheet are adhered to each other, the thermosetting adhesive sheet is made of an epoxy resin composition containing an epoxy resin and an inorganic filler, and at least a portion of an end surface of the metal layer is a tapered surface, and the tapered surface forms an obtuse angle with the second surface.

[0085] According to this configuration, at least a portion of the end face of the metal layer is tapered, and the angle between the tapered surface and the second surface is obtuse, which makes it less likely to damage the mating material that contacts the metal layer, thereby providing an easy-to-handle metal sheet-attached adhesive sheet.

[0086] [7] The metal sheet-attached adhesive sheet according to [6], which has a rectangular shape and has the tapered surfaces on two opposing sides of the rectangle.

[0087] [8] The metal sheet-attached adhesive sheet according to [6] or [7], wherein the central portion in the thickness direction of the tapered surface is in a state of protruding outward.

[0088] 1 Metal layer, 1a First surface, 1b Second surface, 2 Adhesive layer, 2a First adhesive surface, 2b Second adhesive surface, 10 Metal sheet-attached adhesive sheet, I Ｓ１ First tapered surface, I Ｓ２ Second tapered surface S: raw material sheet (laminated sheet), Sa: metal sheet, Sb: thermosetting adhesive sheet, V1: V-groove on first surface, V2: V-groove on second surface

Claims

1. A method for producing a metal sheet-attached adhesive sheet comprising: cutting a laminated sheet comprising a metal layer formed of a metal sheet and an adhesive layer formed of a thermosetting adhesive sheet; wherein, in the laminated sheet, the metal sheet has a first surface and a second surface opposite the first surface; the thermosetting adhesive sheet has a first adhesive surface and a second adhesive surface opposite the first adhesive surface; the first surface of the metal sheet and the second adhesive surface of the thermosetting adhesive sheet are adhered to each other; the thermosetting adhesive sheet is made of an epoxy resin composition containing an epoxy resin and an inorganic filler; and, in the metal sheet-attached adhesive sheet, at least a portion of an end surface of the metal layer is a tapered surface, and an angle formed between the tapered surface and the second surface is an obtuse angle.

2. The method for manufacturing a metal sheet-attached adhesive sheet according to claim 1, wherein the shape of the metal sheet-attached adhesive sheet is a rectangle, and the tapered surfaces are formed on two sides of the rectangle that are positioned opposite each other.

3. A method for manufacturing a metal sheet-attached adhesive sheet according to claim 1 or 2, wherein the tapered surface is formed by cutting the laminated sheet from the metal layer side with a disc cutter to form a V-shaped groove in the laminated sheet.

4. A method for producing a metal sheet-attached adhesive sheet as set forth in claim 3, wherein a V-groove including a first-side V-groove and a second-side V-groove is formed using a disc cutter on each of a first side and a second side opposite to the first side of a laminate sheet, the V-groove being along a line that defines at least a portion of the outer periphery of the metal sheet-attached adhesive sheet, the tapered surface being formed by the second-side V-groove and the first-side V-groove forming a tapered surface on the first side of the laminate sheet that is reverse tapered to the tapered surface, and the metal sheet-attached adhesive sheet has a central portion in the thickness direction that protrudes outward at a location corresponding to the line.

5. The method for manufacturing a metal sheet-attached adhesive sheet according to claim 4, wherein, in forming the V groove along the line, the V groove on the second surface side is formed before the V groove on the first surface side is formed.

6. An adhesive sheet with a metal sheet, comprising a metal layer formed of a metal sheet and an adhesive layer formed of a thermosetting adhesive sheet, wherein the metal sheet has a first surface and a second surface opposite the first surface, the thermosetting adhesive sheet has a first adhesive surface and a second adhesive surface opposite the first adhesive surface, the first surface of the metal sheet and the second adhesive surface of the thermosetting adhesive sheet are adhered to each other, the thermosetting adhesive sheet is formed of an epoxy resin composition containing an epoxy resin and an inorganic filler, and at least a portion of an end surface of the metal layer is a tapered surface, and the tapered surface forms an obtuse angle with the second surface.

7. The metal sheet-attached adhesive sheet according to claim 6, which is rectangular in shape and has said tapered surfaces on two opposing sides of said rectangle.

8. The metal sheet-attached adhesive sheet according to claim 6 or 7, wherein the central portion in the thickness direction at the location where the tapered surface is formed protrudes outward.

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