Method for manufacturing single-sided metal-clad laminate

Abstract

The present application relates to a manufacturing method of a single-sided metal-clad laminate having a metal foil (151, 152) which is adhesively laminated to a thermoplastic resin layer (111, 121) on one side of an adhesive sheet having a core layer (110, 120) formed of a heat-resistant film and thermoplastic resin layers (111, 112, 121, 122) provided on both sides of the core layer. A laminate is formed by heat-laminating a first metal foil (151), a first adhesive sheet (101), a second adhesive sheet (102), and a second metal foil (152), and the laminate is peeled between the first adhesive sheet and the second adhesive sheet, thereby obtaining a first single-sided metal-clad laminate (121) having the first metal foil adhesively laminated on a first main surface of the first adhesive sheet and a second single-sided metal-clad laminate (122) having the second metal foil adhesively laminated on a first main surface of the second adhesive sheet.

Description

Technical Field

[0001] This invention relates to a method for manufacturing a single-sided metal-clad laminate. Background Technology

[0002] Flexible printed circuit boards (FPCs) with patterned metal wiring layers, such as copper, on heat-resistant resin films like polyimide films are used in various electronic devices. With the increasing performance and miniaturization of electronic devices, multilayer FPCs are being developed, which are formed by stacking multiple wiring layers with insulating layers in between.

[0003] In the manufacture of FPCs, double-sided metal-clad laminates are used, which are obtained by laminating metal foils such as copper on both sides of a heat-resistant resin film, and single-sided metal-clad laminates are obtained by laminating metal foils on one side of a heat-resistant resin film. In the manufacture of multilayer FPCs, single-sided metal-clad laminates are primarily used.

[0004] One known method for manufacturing metal-clad laminates involves using a multilayer film with thermoplastic resin layers functioning as adhesive layers on both sides of a heat-resistant resin film (core layer), and then hot-laminating a metal foil onto the thermoplastic resin layers of the multilayer film. A single-sided metal-clad laminate is obtained by laminating a metal foil onto only one side of the multilayer film, which has thermoplastic resin layers on both sides of the core layer. However, in the case of single-sided lamination of a metal foil onto a multilayer film with thermoplastic resin layers on both sides of the core layer, during hot lamination, defects such as fusion between the thermoplastic resin layer on the side without the metal foil and the hot roller may occur.

[0005] Patent Document 1 discloses a method for manufacturing a single-sided metal-coated laminate, in which a metal foil is laminated on one side of a multilayer film. In this method, hot lamination is performed with a metal foil on one side of the multilayer film and a release film on the other side. Patent Document 2 discloses a method in which a non-fusible or low-fusible surface layer is provided on a thermoplastic resin layer on one side of the multilayer film, and a metal foil is provided on a thermoplastic resin layer on the other side of the multilayer film, followed by hot lamination.

[0006] As described in Patent Documents 1 and 2, by performing hot lamination on a thermoplastic resin layer with a release film or surface layer disposed on the side of the unlaminated metal foil, the thermoplastic resin layer can be prevented from fusing with manufacturing equipment such as metal rollers.

[0007] Existing technical documents

[0008] Patent documents

[0009] Patent Document 1: Japanese Patent Application Publication No. 2007-109694

[0010] Patent Document 2: International Publication No. 2021 / 251214 Summary of the Invention

[0011] The problem the invention aims to solve

[0012] The purpose of this invention is to provide a multilayer film with thermoplastic resin layers on both sides of a heat-resistant resin film (core layer) to prevent the thermoplastic resin layers from fusing with manufacturing equipment such as metal rollers, and to provide single-sided metal-coated laminates with higher productivity.

[0013] Solution for solving the problem

[0014] The present invention relates to a method for manufacturing a single-sided metal-clad laminate, the single-sided metal-clad laminate comprising: an adhesive sheet having thermoplastic resin layers on both sides of a core layer formed of a heat-resistant film; and a metal foil tightly laminated to one side of the thermoplastic resin layer of the adhesive sheet.

[0015] A first metal foil, a first adhesive sheet, a second adhesive sheet, and a second metal foil are arranged such that the first main surface of the first metal foil faces the first main surface of the first adhesive sheet, the second main surface of the second adhesive sheet faces the second main surface of the first adhesive sheet, and the first main surface of the second metal foil faces the first main surface of the second adhesive sheet. A laminate containing the first metal foil, the first adhesive sheet, the second adhesive sheet, and the second metal foil is then formed (lamination process). The laminate is then peeled and separated between the first adhesive sheet and the second adhesive sheet (peeling process), thereby simultaneously obtaining a first single-sided metal-clad laminate with the first metal foil tightly laminated on the first main surface of the first adhesive sheet, and a second single-sided metal-clad laminate with the second metal foil tightly laminated on the first main surface of the second adhesive sheet.

[0016] Both the first and second adhesive sheets have thermoplastic resin layers on both sides of a core layer formed of a heat-resistant film. The core layer of the adhesive sheet may be a non-thermoplastic polyimide film. The thermoplastic resin layer of the adhesive sheet may contain thermoplastic polyimide resin. The tensile modulus of elasticity of the adhesive sheet at a temperature of 350°C may be 0.05–1.5 GPa.

[0017] In the lamination process, no other layers may be disposed on the second main surface of the first metal foil and the second main surface of the second metal foil, and heat lamination may be performed with the metal foil in contact with the heat-pressing mechanism. Alternatively, a surface protective film may be disposed on the second main surface of the first metal foil and / or the second main surface of the second metal foil, and heat lamination may be performed while the surface of the metal foil is protected by the surface protective film. When using a surface protective film, in the peeling process, peeling is performed not only between the first adhesive sheet and the second adhesive sheet, but also at the interface between the metal foil and the surface protective film.

[0018] In the lamination process, no other layer may be placed between the first adhesive sheet and the second adhesive sheet. Instead, the lamination is performed with the thermoplastic resin layer (second thermoplastic resin layer) on the second main surface of the first adhesive sheet in contact with the thermoplastic resin layer (second thermoplastic resin layer) on the second main surface of the second adhesive sheet. Alternatively, an intermediate protective film may be placed between the first adhesive sheet and the second adhesive sheet for lamination.

[0019] When no other layer is disposed between the first adhesive sheet and the second adhesive sheet, the peeling process involves peeling at the interface between the second thermoplastic resin layer of the first adhesive sheet and the second thermoplastic resin layer of the second adhesive sheet. When an intermediate protective layer is disposed between the first adhesive sheet and the second adhesive sheet, the peeling process involves peeling at the interface between the second thermoplastic resin layer of the first adhesive sheet and the intermediate protective film, and at the interface between the second thermoplastic resin layer of the second adhesive sheet and the intermediate protective film.

[0020] The effects of the invention

[0021] In the method of this invention, the thermoplastic resin layer of the adhesive sheet does not come into contact with the hot pressing mechanism such as the hot roller, thus preventing defects such as fusion between the thermoplastic resin layer and the hot pressing mechanism. Furthermore, two single-sided metal laminates can be obtained simultaneously through a single hot lamination, thereby significantly improving the productivity of single-sided metal-coated laminates. Attached Figure Description

[0022] Figure 1 This is a cross-sectional view of a single-sided metal-clad laminate according to one embodiment.

[0023] Figure 2 A cross-sectional view illustrating an example of the manufacturing process of a single-sided metal-clad laminate.

[0024] Figure 3 A cross-sectional view illustrating an example of the manufacturing process of a single-sided metal-clad laminate.

[0025] Figure 4 A cross-sectional view illustrating an example of the manufacturing process of a single-sided metal-clad laminate.

[0026] Figure 5 A cross-sectional view illustrating an example of the manufacturing process of a single-sided metal-clad laminate. Detailed Implementation

[0027] Figure 1This is a cross-sectional view showing the laminated structure of a single-sided metal-clad laminate. The single-sided metal-clad laminate 20 includes a metal foil 5 tightly laminated to one side of an adhesive sheet 1. The adhesive sheet 1 is a multilayer film having thermoplastic resin layers 11 and 12 functioning as adhesive layers on both sides of a core layer 10. In the single-sided metal-clad laminate 20, the metal foil 5 is laminated on the first thermoplastic resin layer 11 on one side of the adhesive sheet 1. No metal foil is provided on the second thermoplastic resin layer 12 on the other side of the adhesive sheet 1, leaving the thermoplastic resin layer 12 exposed.

[0028] Hereinafter, the side of the adhesive sheet with the metal foil disposed thereon will sometimes be referred to as the "first main surface", the side without the metal foil disposed thereon will sometimes be referred to as the "second main surface", the side of the adhesive sheet with the metal foil attached thereon will sometimes be referred to as the "first main surface", and the other main surface will sometimes be referred to as the "second main surface". In addition, the thermoplastic resin layer 11 disposed on the first main surface of the core layer 10 will sometimes be referred to as the "first thermoplastic resin layer", and the thermoplastic resin layer 12 disposed on the second main surface of the core layer 10 will sometimes be referred to as the "second thermoplastic resin layer".

[0029] Figure 2 A through C are schematic cross-sectional views illustrating the manufacturing process of a single-sided metal-clad laminate according to an embodiment of the present invention. In this invention, a laminate 502 is fabricated by hot lamination of two adhesive sheets 101, 102 and two metal foils 151, 152 overlapped together. Figure 2 A, Figure 2 B: Lamination process), and peeling is performed between the two adhesive sheets 101 and 102. Figure 2 (C: Peeling process). Thus, a first single-sided metal-clad laminate 121, with a first metal foil 151 bonded to the thermoplastic resin layer 111 of the first main surface of the first adhesive sheet 101, and a second single-sided metal-clad laminate 122, with a second metal foil 152 bonded to the thermoplastic resin layer 121 of the first main surface of the second adhesive sheet 102. That is, according to the method of the present invention, two single-sided metal-clad laminates can be obtained by a single heat lamination.

[0030] [Materials constituting single-sided metal-clad laminates]

[0031] As described above, the single-sided metal-coated laminate has a metal foil 5 on one side of the adhesive sheet 1.

[0032] <Adhesive Sheet>

[0033] The adhesive sheet 1 is a multilayer film with thermoplastic resin layers 11 and 12 on both sides of the core layer 10, which function as adhesive layers.

[0034] (Core layer)

[0035] For the core layer 10, it is required to withstand the heating temperatures during hot lamination in the FPC manufacturing process. Therefore, a high heat-resistant film is used as the core layer 10. As the resin material for the core layer 10, polyimide film, polyethylene naphthalate film, etc., are preferred, with non-thermoplastic resin materials that are not thermoplastic being more preferred. In the case of high heat resistance and excellent electrical properties, a non-thermoplastic polyimide film is preferred as the core layer 10. The core layer 10 preferably contains 80% by weight or more of non-thermoplastic polyimide, more preferably 90% by weight or more of non-thermoplastic polyimide.

[0036] "Non-thermoplastic polyimide" refers to polyimide that does not soften or exhibit adhesiveness even when heated. Specifically, polyimide that maintains its shape without wrinkling or elongating when a single-layer polyimide film is heated at 380°C for 2 minutes is included in "non-thermoplastic polyimide". Additionally, polyimide that does not substantially exhibit a glass transition temperature is also included in non-thermoplastic polyimide. The glass transition temperature is the temperature at which the storage modulus shows an inflection point, as measured by a dynamic viscoelasticity measuring device (DMA). Resin materials that "substantially do not have a glass transition temperature" refer to those that begin thermal decomposition before reaching the glass transition state.

[0037] Polyimides are typically obtained by polymerizing a diamine with a tetracarboxylic dianhydride to prepare a polyimide precursor (polyamic acid), followed by dehydration and ring-closure of the polyamic acid to achieve imidization. In the preparation of non-thermoplastic polyimides, a combination of aromatic diamines and aromatic tetracarboxylic dianhydrides is suitable as the monomer.

[0038] Examples of aromatic diamines include: 3,3'-diaminodiphenyl ether, 3,4'-diaminodiphenyl ether, 4,4'-diaminodiphenyl ether, 2,2-bis{4-(4-aminophenoxy)phenyl}propane, 2,2-bis{4-(4-aminophenoxy)phenyl}hexafluoropropane, bis{4-(3-aminophenoxy)phenyl}sulfone, bis{4-(4-aminophenoxy)phenyl}sulfone, 1,3-bis(3-aminophenoxy)benzene, 1,3-bis(4-aminophenoxy)benzene, 1,4-bis(4-aminophenoxy)benzene, 3,3'-diaminobenzophenone, 4,4'-diaminobenzophenone, 3,3'-dichlorobenzene... Aniline, 3,3'-dimethylbenzidine, 2,2'-dimethylbenzidine, 3,3'-dimethoxybenzidine, 2,2'-dimethoxybenzidine, 1,4-diaminobenzene (p-phenylenediamine), 1,3-diaminobenzene (m-phenylenediamine), 4,4'-diaminodiphenyl sulfone, 3,3'-diaminodiphenyl sulfone, 9,9-bis(4-aminophenyl)fluorene, 4,4'-(1,4-phenylenebis(1-methylethylene))bisaniline, 4,4'-(1,3-phenylenebis(1-methylethylene))bisaniline, 4,4'-diaminobenzoylaniline, 2,2'-dimethylbiphenyl-4,4'-diamine, etc. Two or more aromatic diamines may also be used.

[0039] Examples of aromatic tetracarboxylic dianhydrides include: 3,3',4,4'-benzophenone tetracarboxylic dianhydride, 2,2',3,3'-benzophenone tetracarboxylic dianhydride, 4,4'-oxophthalic dianhydride, 3,4'-oxophthalic dianhydride, ethylene bis(triphthalic acid monoester anhydride), bisphenol A bis(triphthalic acid monoester anhydride), pyromellitic dianhydride, 2,3,6,7-naphthalene tetracarboxylic dianhydride, 1,4,5,8-naphthalene tetracarboxylic dianhydride, 3,3',4,4'-diphenylsulfone tetracarboxylic dianhydride, 3,3 Aromatic tetracarboxylic anhydrides include ',4,4'-dimethyldiphenylsilanetetracarboxylic anhydride, 3,3',4,4'-tetraphenylsilanetetracarboxylic anhydride, 1,2,3,4-furantetracarboxylic anhydride, 4,4'-bis(3,4-dicarboxyphenoxy)diphenylpropane anhydride, 4,4'-hexafluoroisopropylidene phthalic anhydride, 3,3',4,4'-biphenyltetracarboxylic anhydride, 2,3,3',4'-biphenyltetracarboxylic anhydride, p-phenylenebis(triphthalic acid monoester anhydride), and p-phenylene diphthalic anhydride. Two or more aromatic tetracarboxylic anhydrides can also be used.

[0040] Polyamic acid is obtained by reacting a diamine with a tetracarboxylic dianhydride in substantially equimolar amounts. The order of addition, the combination of monomers, and their composition are not particularly limited. The organic solvent used for the polymerization of polyamic acid is not particularly limited, as long as it dissolves the diamine, tetracarboxylic dianhydride, and polyamic acid. Preferably, amide solvents such as N,N-dimethylformamide, N,N-diethylformamide, N,N-dimethylacetamide, and N-methyl-2-pyrrolidone are preferred. The polymerization temperature is preferably -10°C to 50°C. The reaction time is not particularly limited, typically ranging from several minutes to several hours. The solids concentration of the polyamic acid solution is typically 5% to 35% by weight, preferably 10% to 30% by weight.

[0041] Polyimide is obtained by imidizing (dehydrating and ring-closing) polyamic acid, which is a precursor of polyimide. A curing agent can be added to the polyamic acid solution during imidization. Examples of curing agents include dehydrating agents and imidization catalysts. Examples of dehydrating agents include: aliphatic anhydrides, aromatic anhydrides, N,N'-dialkylcarbodiimides, lower aliphatic halides, halogenated lower aliphatic anhydrides, arylsulfonic acid dihalides, thionyl halides, etc. Examples of imidization catalysts include: aliphatic tertiary amines, aromatic tertiary amines, heterocyclic tertiary amines, etc.

[0042] The core layer may also contain fillers in addition to non-thermoplastic polyimide resin. Examples of filler materials include: silica, titanium dioxide, alumina, silicon nitride, boron nitride, dicalcium phosphate, calcium phosphate, and mica.

[0043] (Thermoplastic resin layer)

[0044] Examples of materials for the double-sided thermoplastic resin layers 11 and 12 disposed on the core layer 10 include: polycarbonate resins, acrylonitrile-styrene copolymer resins, and thermoplastic polyimide resins. From the viewpoint of heat resistance and adhesion to the core layer, the thermoplastic resin layers 11 and 12 preferably contain thermoplastic polyimide resin, and more preferably contain 50% by weight or more of thermoplastic polyimide resin.

[0045] The thermoplastic resin layer 11 disposed on the first main surface of the core layer 10 and the thermoplastic resin layer 12 disposed on the second main surface of the core layer 10 may have the same composition or different compositions. From the viewpoint of suppressing warping of the adhesive sheet and the single-sided metal-coated laminate and simplifying the manufacturing process, it is preferable that the thermoplastic resin layers 11 and 12 disposed on both sides of the core layer have the same composition.

[0046] From the viewpoint of adhesion to the metal foil 5 and heat resistance, the thermoplastic resin layers 11 and 12 preferably have a glass transition temperature in the range of 150°C to 320°C. The glass transition temperature of the thermoplastic resin layers 11 and 12 may also be 200°C to 300°C. The glass transition temperature is the temperature at which the storage modulus inflection point is displayed, as measured by a dynamic viscoelasticity measuring device (DMA).

[0047] Similar to non-thermoplastic polyimides, thermoplastic polyimides are obtained through the dehydration and ring-closure of polyamic acid, which serves as a polyimide precursor. In the preparation of thermoplastic polyimides, combinations of aromatic diamines and aromatic tetracarboxylic dianhydrides are also suitable as monomers. Various properties of the polyimide can be adjusted by selecting the diamine and tetracarboxylic dianhydride.

[0048] Generally, if the proportion of a rigid aromatic diamine increases, the glass transition temperature tends to increase, accompanied by an increase in the elastic modulus at high temperatures and a decrease in adhesion and processability. Examples of components used in thermoplastic polyimide resins include benzophenone tetracarboxylic dianhydride, biphenyl tetracarboxylic dianhydride, oxydiphthalic dianhydride, and biphenyl sulfone tetracarboxylic dianhydride as tetracarboxylic dianhydride, and aromatic diamines having an aminophenoxy group as the diamine. In the diamine used to prepare thermoplastic polyimides, the proportion of a rigid aromatic diamine is preferably 40 mol% or less, more preferably 30 mol% or less, and even more preferably 20 mol% or less.

[0049] (Making of adhesive sheets)

[0050] There is no particular limitation on the method for manufacturing the adhesive sheet having thermoplastic resin layers 11 and 12 on both sides of the core layer 10. For example, methods such as forming thermoplastic resin layers sequentially or simultaneously on the two main surfaces of the core layer 10, and methods such as multi-layer co-extrusion of the material of the core layer 10 and the material of the thermoplastic resin layers 11 and 12 from a multi-layer mold are also applicable.

[0051] Polyimides obtained by imidizing polyamic acid, which is obtained by polymerizing aromatic diamines with aromatic tetracarboxylic dianhydrides, have low solubility in organic solvents after imidization. Therefore, when the core layer 10 and thermoplastic resin layers 11 and 12 are polyimides, it is preferable to form the polyamic acid solution (polyimide precursor) into a film before imidization.

[0052] When a multilayer polyimide film with thermoplastic polyimide layers 11 and 12 on both sides of a non-thermoplastic polyimide core layer 10 is produced by multilayer co-extrusion, it is preferable to: apply a polyamic acid solution, which serves as a precursor for the non-thermoplastic polyimide constituting the core layer 10, and a polyamic acid solution, which serves as a precursor for the thermoplastic polyimide constituting the thermoplastic resin layers 11 and 12, in a film form onto a support substrate by three-layer co-extrusion; remove the solvent by heating if necessary; and then perform imidization by heating. As described above, a curing agent may be added to the polyamic acid solution to promote imidization. In the case of three-layer co-extrusion, a curing agent may be added only to the polyimide precursor of the core layer 10, or a curing agent may be added to both the polyimide precursor of the core layer 10 and the polyimide precursor of the thermoplastic resin layers 11 and 12. The polyimide in the core layer 10 and thermoplastic resin layers 11 and 12 can be fully imidized, or may contain partially unimidized structures (open-ring polyamic acid).

[0053] There are no particular limitations on the thickness of the core layer 10 and the thickness of the thermoplastic resin layers 11 and 12. In order to prevent warping in the multilayer film state, it is preferable to adjust the thickness balance by considering the linear expansion coefficient of each layer.

[0054] The thickness of the core layer 10 is preferably 3 to 50 μm, more preferably 5 to 40 μm. The thickness of each of the thermoplastic resin layers 11 and 12 is preferably 0.5 to 15 μm, more preferably 1 to 10 μm. The thicknesses of the thermoplastic resin layers 11 and 12 disposed on both sides of the core layer 10 may be the same or different. From the viewpoint of suppressing warping, it is preferable that the difference between the thickness of the thermoplastic resin layer 11 and the thickness of the thermoplastic resin layer 12 is small. The ratio of the thickness of the thermoplastic resin layer 11 to the thickness of the thermoplastic resin layer 12 is preferably 0.7 to 1.3, more preferably 0.8 to 1.2, and even more preferably 0.9 to 1.1.

[0055] The thickness of each of the thermoplastic resin layers 11 and 12 is preferably 0.05 to 0.5 times the thickness of the core layer 10, or approximately 0.1 to 0.4 times the thickness of the core layer 10. The total thickness of the adhesive sheet 1 is preferably 5 to 50 μm. If the thickness is within this range, it can be suitable as a substrate for FPC.

[0056] Commercially available products can also be used as multilayer films with thermoplastic resin layers on both sides of the core layer. For example, the "Pixeo" series manufactured by Kaneka is an example of a multilayer polyimide film consisting of three layers with thermoplastic polyimide layers on both sides of a non-thermoplastic polyimide core layer.

[0057] The tensile modulus of elasticity of the adhesive sheet 1 at 350°C is preferably 0.05–1.5 GPa. If the elastic modulus of the adhesive sheet 1 at the temperature during hot lamination is too high, the adhesive sheet will be too hard and will not be able to adequately buffer the lamination pressure, which may lead to appearance defects such as wrinkles during lamination. On the other hand, if the elastic modulus of the adhesive sheet 1 at the temperature during hot lamination is too low, the adhesive sheet will be easily deformed by the lamination pressure, and may be prone to transfer of micro-damage to the surfaces of the hot roller, protective film, etc., or appearance defects caused by dents caused by attached foreign matter.

[0058] By ensuring that the tensile modulus of elasticity of the adhesive sheet 1 at 350°C is within the aforementioned range, appearance defects caused by wrinkles and deformation during hot lamination can be suppressed. The tensile modulus of elasticity of the adhesive sheet at 350°C is more preferably 0.08–1 GPa, and even more preferably 0.1–0.7 GPa, but may also be 0.12–0.6 GPa or 0.14–0.5 GPa.

[0059] Since the glass transition temperatures of the thermoplastic resin layers 11 and 12 of the adhesive sheet 1, which are multilayer films, are typically below 350°C, the tensile modulus of elasticity at 350°C is significantly affected by the characteristics of the core layer 10. When the core layer 10 is a non-thermoplastic polyimide film, there is a tendency for a higher proportion of monomers with rigid structures among the monomer components constituting the polyimide (tetracarboxylic dianhydride and diamine) to result in a greater tensile modulus of elasticity at 350°C.

[0060] A representative example of a tetracarboxylic dianhydride with a rigid structure is pyromellitic dianhydride (PMDA), and a representative example of a diamine with a rigid structure is p-phenylenediamine (PDA). There is a tendency for the tensile modulus of elasticity at 350°C to increase as the proportion of PMDA in the tetracarboxylic dianhydride component and the proportion of PDA in the diamine component of the polyimide increases.

[0061] <Metal Foil>

[0062] For the metal foil 5, copper or copper alloys, stainless steel or its alloys, nickel or nickel alloys (including alloy 42), aluminum or aluminum alloys, etc., are preferred as the metal material for high conductivity. For ease of lamination, metal foil is preferred as the metal foil 5; similar to conventional FPCs, rolled copper foil, electrolytic copper foil, etc., are preferred. A rust-preventive layer, a heat-resistant layer, an adhesive layer, etc., may also be provided on the surface of the metal foil. The thickness of the metal foil 5 is not particularly limited and can be selected according to the composition of the FPC and the required conductivity. The thickness of the metal foil 5 is, for example, 3 to 30 μm, preferably 5 to 20 μm. From the viewpoint of adhesion to the thermoplastic resin layer, the surface roughness (Rz) of the metal foil 5 is preferably 0.01 μm to 1 μm.

[0063] [Manufacturing method of single-sided metal-clad laminate]

[0064] like Figure 2 As shown in A to C, a laminate 502 is fabricated by hot lamination of two adhesive sheets 101 and 102 and two metal foils 151 and 152 (lamination process), and then peeling is performed between the two adhesive sheets (peeling process). Through these processes, two single-sided metal-coated laminates 121 and 122 are obtained.

[0065] <Layering Process>

[0066] First, the first metal foil 151, the first adhesive sheet 101, the second adhesive sheet 102, and the second metal foil 152 are arranged sequentially along a direction orthogonal to the sheet surface. Figure 2 (A) The first metal foil 151 is a metal foil bonded to the thermoplastic resin layer 111 on the first main surface of the first adhesive sheet 101, and the second metal foil 152 is a metal foil bonded to the thermoplastic resin layer 121 on the first main surface of the second adhesive sheet 102.

[0067] In this state, the first main surface of the first metal foil 151 faces the thermoplastic resin layer 111 of the first main surface of the first adhesive sheet 101, the first main surface of the first metal foil 152 faces the thermoplastic resin layer 121 of the first main surface of the second adhesive sheet 102, and the thermoplastic resin layer 122 of the second main surface of the second adhesive sheet 102 faces the thermoplastic resin layer 112 of the second main surface of the first adhesive sheet 101.

[0068] Furthermore, in this specification, "opposite" means that two surfaces are arranged facing each other, and other layers may exist between the two surfaces. For example, as described below, an intermediate protective film 71 (see reference) may be disposed between the first adhesive sheet 101 and the second adhesive sheet 102. Figure 3 A and Figure 5 (A) In this case, although an intermediate protective film 71 is disposed between the thermoplastic resin layer 112 of the second main surface of the first adhesive sheet 101 and the thermoplastic resin layer 122 of the second main surface of the second adhesive sheet 102, since the second main surface of the first adhesive sheet 101 and the second main surface of the second adhesive sheet 102 are arranged in a manner facing each other, the second main surface of the second adhesive sheet 102 is opposite to the second main surface of the first adhesive sheet 101.

[0069] With the first metal foil 151, the first adhesive sheet 101, the second adhesive sheet 102, and the second metal foil 152 sequentially arranged, a laminate 502 can be formed by thermal lamination of the first metal foil 151 and the second main surface of the second metal foil 152 through pressure application. Figure 2 (B).

[0070] Examples of hot lamination (hot pressing) include: batch hot pressing using single-plate pressing, continuous processing using a double-belt pressing (DBP) device, and hot pressing using hot rollers. From a productivity point of view, the following method is preferred: hot roller lamination using a hot roller lamination device equipped with hot rollers for heating and pressurizing the material, in a roller-to-roll manner. The hot roller lamination device has one pair (two) or more hot rollers, and hot lamination is performed by clamping the stacked object with two hot rollers and heating and pressing one side of it. For ease of heating and temperature adjustment, metal rollers are preferred.

[0071] From the perspectives of adhesion (peel strength) between the adhesive film and the metal foil in a single-sided metal-clad laminate, dimensional stability of the single-sided metal-clad laminate, and suppression of warpage, the heating temperature during hot lamination is preferably above the glass transition temperature (Tg) of the thermoplastic resin layer of the adhesive sheet. Hot lamination is performed by heating to above the glass transition temperature of the thermoplastic resin layers 111 and 121, bonding the thermoplastic resin layer 111 of the first adhesive sheet 101 to the first metal foil 151, and the thermoplastic resin layer 121 of the second adhesive sheet 102 to the first metal foil 152. The heating temperature is preferably (Tg+0)℃~(Tg+180)℃, more preferably (Tg+10)℃~(Tg+160)℃, and may also be (Tg+20)℃~(Tg+150)℃. The heating temperature can be 280~400℃, 300~380℃, or 320~370℃.

[0072] <Stripping Process>

[0073] Through the above-described lamination process, a laminate 502 is formed. In this laminate 502, a first single-sided metal-clad laminate 121, on which a first adhesive sheet 101 and a first metal foil 151 are laminated, and a second single-sided metal-clad laminate 122, on which a second adhesive sheet 102 and a second metal foil 152 are laminated, are tightly laminated together via a thermoplastic resin layer 112 on the second main surface of the first adhesive sheet 101 and a thermoplastic resin layer 122 on the second main surface of the second adhesive sheet 102. Figure 2 (B) By peeling and separating the laminate 502 between the first adhesive film 101 and the second adhesive film 102, two single-sided metal-coated laminates 121 and 122 are obtained.

[0074] exist Figure 2In the laminate shown in B, the adhesive sheet and the metal foil are firmly bonded at the interface between the thermoplastic resin layer 111 on the first main surface of the first adhesive sheet 101 and the first metal foil 151, and at the interface between the thermoplastic resin layer 121 on the first main surface of the second adhesive sheet 102 and the second metal foil 152. In contrast, the adhesive force at the interface between the thermoplastic resin layer 112 on the second main surface of the first adhesive sheet 101 and the thermoplastic resin layer 122 on the second main surface of the second adhesive sheet 102 is smaller, so it is easy to peel the laminate 502 between the first adhesive sheet and the second adhesive sheet.

[0075] In the above manufacturing method, in the laminate 502, the second main surfaces of two adhesive sheets 101 and 102 are arranged opposite each other. The thermoplastic resin layers 112 and 122 on the second main surfaces of the adhesive sheets do not come into contact with the hot pressing mechanism such as hot rollers, thus preventing defects such as fusion between the thermoplastic resin layers and the hot pressing mechanism. In addition, since the laminate 502 is formed by hot lamination in one step and then separated between the adhesive sheets 101 and 102, two single-sided metal laminates are obtained simultaneously, thus doubling the productivity of single-sided metal laminates.

[0076] <Process of laminating with hot rollers>

[0077] As described above, hot lamination is preferably performed using a hot roll lamination apparatus that performs hot pressing with hot rolls. In hot roll lamination, hot lamination is performed while continuously conveying the first metal foil 151, the first adhesive sheet 101, the second adhesive sheet 102, and the second metal foil 152 constituting the laminate 502, thus resulting in excellent productivity.

[0078] The hot roll laminating apparatus uses the following configuration: an outgoing mechanism is provided upstream of the hot roll, which serves as a hot pressing mechanism, to continuously feed the laminated materials from the winding bodies of each laminated material; and a winding mechanism is provided downstream of the hot roll to wind the laminated materials onto the winding body. A specific example of the outgoing and winding mechanisms is a roll winding machine.

[0079] The laminate 502 formed by hot roller lamination can be wound up by a winding mechanism while two single-sided metal-coated laminates are stacked, or it can be separated into two single-sided metal-coated laminates 121 and 122 by a peeling process after hot lamination.

[0080] [Examples of variations in layered morphology]

[0081] Figure 2In the embodiments shown in A to C, no other layers are disposed between the first adhesive sheet 101 and the second adhesive sheet 102. Through a lamination process, a laminate 502 is formed in which the thermoplastic resin layer 112 of the second main surface of the first adhesive sheet 101 and the thermoplastic resin layer 122 of the second main surface of the second adhesive sheet 102 are in contact. The laminate obtained through the lamination process may also have an intermediate protective film 71 disposed between the thermoplastic resin layer 112 of the second main surface of the first adhesive sheet 101 and the thermoplastic resin layer 122 of the second main surface of the second adhesive sheet 102.

[0082] For example, through such Figure 3 As shown in Figure A, thermal lamination is performed with an intermediate protective film 71 disposed between the first adhesive sheet 101 and the second adhesive sheet 102, thereby achieving the desired effect. Figure 3 As shown in B, a laminate 503 is obtained, in which the thermoplastic resin layer 112 of the second main surface of the first adhesive sheet 101 is in contact with one side (first main surface) of the intermediate protective film 71, and the thermoplastic resin layer 122 of the second main surface of the second adhesive sheet 102 is in contact with the other side (second main surface) of the intermediate protective film 71.

[0083] When an intermediate protective film 71 is disposed between the first adhesive sheet 101 and the second adhesive sheet 102, in the peeling process, the first adhesive sheet 101 and the second adhesive sheet 102 are peeled off by peeling off the interface between the thermoplastic resin layer 112 on the second main surface of the first adhesive sheet 101 and the intermediate protective film 71, and the interface between the thermoplastic resin layer 122 on the second main surface of the second adhesive sheet 102 and the intermediate protective film 71.

[0084] In this embodiment, the second thermoplastic resin layer 112 of the first adhesive sheet 101 and the second thermoplastic resin layer 122 of the second adhesive sheet 102 do not come into contact. Therefore, even when the adhesive force of the thermoplastic resin layer of the adhesive sheet is high, the thermoplastic resin layers 112 and 122 of the two adhesive sheets 101 and 102 will not stick together, and the peeling process can be carried out stably.

[0085] In the lamination process, a surface protective material may also be placed between a hot pressing mechanism such as a hot roller (not shown) and the metal foils 151 and 152. For example, by means of... Figure 4 As shown in Figure A, thermal lamination is performed with a first surface protective film 91 disposed on the second main surface of the first metal foil 151 and a second surface protective film 92 disposed on the second main surface of the second metal foil 152, thereby achieving the desired effect. Figure 4 As shown in B, a laminate 504 is obtained, wherein a first surface protective film 91 is laminated on the second main surface of the first metal foil 151, and a second surface protective film 92 is laminated on the second main surface of the second metal foil 152.

[0086] When surface protective films 91 and 92 are disposed on the second main surfaces of metal foils 151 and 152, in the peeling process, in addition to peeling the first adhesive sheet 151 and the second adhesive sheet 152, peeling is also performed at the interface between the first metal foil 151 and the first surface protective film 91 and at the interface between the second metal foil 152 and the second surface protective film 92, so that the surface protective film is peeled off from the surface of the single-sided metal-coated laminate.

[0087] In this embodiment, during hot lamination, a surface protective film 91, 92 is disposed between the hot pressing mechanism such as the hot roller and the metal foil 151, 152. The hot pressing mechanism does not directly contact the metal foil, thus reducing appearance defects such as damage to the metal foil during hot pressing.

[0088] Figure 4 Figures A through C show a method of configuring surface protective films 91 and 92 on both sides of the metal foils 151 and 152, but a surface protective film may also be configured on only one side of the metal foil. Figure 4 As shown in B, when the laminated body 504 after heat lamination has a symmetrical front and back side configuration, there is a tendency to suppress warping of the laminated body and the single-sided metal-coated laminate. Therefore, when a surface protective film is disposed on the metal foil, it is preferable to... Figure 4 As shown in A to C, surface protective films 91 and 92 are disposed on double-sided metal foils.

[0089] It is also possible to Figure 5 As shown in Figure A, thermal lamination is performed under the following conditions: an intermediate protective film 71 is disposed between the first adhesive sheet 101 and the second adhesive sheet 102, and a first surface protective film 91 is disposed on the second main surface of the first metal foil 151, and a second surface protective film 92 is disposed on the second main surface of the second metal foil 152. In this embodiment, as... Figure 4 As shown in B, the laminated body 505 after thermal lamination has a structure in which a first surface protective film 91, a first adhesive sheet 101, an intermediate protective film 71, a second adhesive sheet 102, and a second surface protective film 92 are stacked in sequence.

[0090] The laminate 505 is peeled and separated at the interfaces of the first surface protective film 91 and the first metal foil 151, the second surface protective film 92 and the second metal foil 152, the first adhesive sheet 101 and the intermediate protective film 71, and the second adhesive sheet 102 and the intermediate protective film 71, thereby achieving the desired result. Figure 5 As shown in C, two single-sided metal-clad laminates 101 and 102 were obtained.

[0091] <Protective Film>

[0092] The surface protective films 91 and 92 disposed on the surface of the metal foil and the intermediate protective film 71 disposed between the two adhesive sheets can have functions such as preventing the fusion of the thermoplastic resin layer between the hot pressing mechanism and the adhesive sheet, preventing excessive fusion of the thermoplastic resin layers with each other, and preventing wrinkles from occurring during hot lamination.

[0093] These protective films are not particularly limited, as long as they can withstand the heating temperature during hot lamination. Suitable materials include heat-resistant resin films such as non-thermoplastic polyimide films, and metal foils such as copper foil, aluminum foil, and SUS foil. From the viewpoints of heat resistance and reusability, non-thermoplastic polyimide films are particularly preferred. From the viewpoints of processability and preventing wrinkles during lamination, the thickness of the protective film is preferably 25–300 μm, more preferably 50–250 μm, and can also be 75–200 μm.

[0094] When using non-thermoplastic polyimide film as a protective film, various known films can be used, such as commercially available polyimide films such as Kaneka's "Apical" series, Ube Industries' "Upilex" series, and Toray DuPont's "Kapton" series.

[0095] Used in the application of hot roller lamination equipment Figures 3-5 In the case of the protective film process shown, the protective film is continuously fed out by the feeding mechanism and then heat-pressed together with the metal foil and adhesive sheet by a hot roller. After the peeling process, the protective film peeled from the single-sided metal-coated laminate is wound into a roll by the winding mechanism. The protective film can be reused. When reusing the protective film, it is preferable to wind it in a way that the positions of both ends of the protective film in the width direction are fixed. To align the positions of the two ends of the film in the width direction, an end position detection mechanism and a winding position correction mechanism can be provided on the path of the hot roller laminating device.

[0096] Flexible printed wiring board

[0097] The aforementioned single-sided metal-clad laminate 20 is suitable for manufacturing flexible printed wiring boards (FPCs). An FPC can be a multilayer printed wiring board with multiple wiring layers stacked with insulating layers spaced apart. In a multilayer printed wiring board, the adhesive sheet 1 serves as the insulating layer between the multiple wiring layers.

[0098] A wiring layer (first wiring layer) is formed by patterning the metal foil 5 of the single-sided metal-clad laminate 20. Multilayering is achieved by stacking this single-sided wiring substrate with a substrate containing other wiring layers (second wiring layers). For example, multilayering is achieved by bonding the side of the single-sided metal-clad laminate that does not have a wiring layer (second thermoplastic resin layer 12) having the first wiring layer obtained by patterning the metal foil 5 to the wiring layer (second wiring layer) of another substrate. The thermoplastic resin layer 12 of the adhesive sheet 1 can be bonded to the wiring layers of other substrates via adhesive sheets such as bonding sheets.

[0099] Example

[0100] The following embodiments illustrate the invention in more detail, but the invention is not limited to the following embodiments.

[0101] Fabrication of multilayer polyimide films

[0102] <Manufacturing Example 1>

[0103] (Preparation of polyamic acid solution for the core layer)

[0104] While maintaining the reaction system under a nitrogen atmosphere at 20°C, N,N-dimethylformamide (DMF) was stirred, and diamine and tetracarboxylic anhydride were added sequentially in the molar ratio shown in Table 1 and allowed to react to obtain a polyamic acid solution A with a viscosity of 3000 poise.

[0105] (Preparation of polyamic acid solution for thermoplastic resin layer)

[0106] While maintaining the reaction system under a nitrogen atmosphere at 20°C, DMF was stirred, and diamine and tetracarboxylic anhydride were added sequentially in the molar ratio shown in Table 1 and allowed to react to obtain a polyamic acid solution B with a viscosity of 1000 poise.

[0107] (Film forming and imidization)

[0108] Add 50 parts by weight of a curing agent solution containing acetic anhydride / isoquinoline / DMF in a weight ratio of 33 / 10 / 57 to 100 parts by weight of polyamic acid solution A, and stir and degas at a temperature below 0°C to prepare a core layer forming solution. For polyamic acid solution B, add DMF at a solid content concentration of 10% by weight and dilute, then stir and degas at a temperature below 0°C to prepare a thermoplastic resin layer forming solution.

[0109] Using a triple coating apparatus, three layers were coated on a metal strip: a thermoplastic resin layer forming solution (dry thickness 4 μm), a core layer forming solution (dry thickness 17 μm), and another thermoplastic resin layer forming solution (dry thickness 4 μm). After heating at 110°C for 180 seconds, the self-supporting gel film was peeled off from the metal strip. Subsequently, the film was heated at 300°C for 56 seconds and then at 380°C for 49 seconds to obtain a multilayer polyimide film 1 with a total thickness of 25 μm, having thermoplastic polyimide layers on both sides of a core layer containing non-thermoplastic polyimide.

[0110] <Manufacturing Example 2>

[0111] Under a nitrogen atmosphere and at 20°C, DMF was stirred while diamine and tetracarboxylic anhydride were added sequentially in the molar ratios shown in Table 1 and allowed to react to obtain a polyamic acid solution C with a viscosity of 2000 poise. Except that polyamic acid solution C was used instead of polyamic acid solution A as the core layer forming solution, a multilayer polyimide film 2 with a total thickness of 25 μm was obtained in the same manner as in Manufacturing Example 1.

[0112] <Manufacturing Example 3>

[0113] While maintaining the reaction system under a nitrogen atmosphere at 20°C, DMF was stirred, and diamine and tetracarboxylic anhydride were added sequentially in the molar ratio shown in Table 1 and allowed to react to obtain polyamic acid solution D with a viscosity of 1500 poise and polyamic acid solution E with a viscosity of 1000 poise.

[0114] Polyamic acid solution D was used instead of polyamic acid solution A as the core layer forming solution, and polyamic acid solution E was used instead of polyamic acid solution B as the thermoplastic resin layer forming solution. The composition of the curing agent solution added to the core layer forming solution was changed to acetic anhydride / isoquinoline / DMF = 42 / 21 / 37. Otherwise, a multilayer polyimide film 3 with a total thickness of 25 μm was obtained in the same manner as in Manufacturing Example 1.

[0115] <Evaluation of Multilayer Polyimide Films>

[0116] The tensile modulus of elasticity of the multilayer polyimide films obtained in Examples 1-3 was determined at 350°C using a tensile testing machine. Additionally, a single-layer polyimide film with a thickness of approximately 10 μm was prepared using polyamic acid solutions B and D, and dynamic viscoelasticity was measured. The temperature at which the storage modulus inflection point was displayed was set as the glass transition temperature of the thermoplastic polyimide.

[0117] Table 1 shows the composition of the core layer and thermoplastic resin layer in the multilayer polyimide films of Examples 1-3, as well as the glass transition temperature (Tg) of the thermoplastic resin layer and the tensile modulus of elasticity of the multilayer film at 350°C. In Table 1, diamine and tetracarboxylic dianhydride are referred to by the following abbreviations.

[0118] <Diamine>

[0119] PDA: p-phenylenediamine

[0120] TPE-R: 1,3-Bis(4-aminophenoxy)benzene

[0121] ODA: 4,4'-Diaminodiphenyl ether

[0122] BAPP: 2,2-bis[4-(4-aminophenoxy)phenyl]propane

[0123] m-TB: 4,4'-diamino-2,2'-dimethylbiphenyl

[0124] <Tetracarboxylic dianhydride>

[0125] PMDA: Pyromellitic dianhydride

[0126] BPDA: 3,3',4,4'-Biphenyltetracarboxylic acid dianhydride

[0127] BTDA: 3,3',4,4'-benzophenone tetracarboxylic dianhydride

[0128] ODPA: 4,4'-O-diphthalic anhydride

[0129] [Table 1]

[0130]

[0131] [Example 1]

[0132] A multilayer polyimide film 1 was used as the adhesive sheet, and a 12μm thick rolled copper foil ("GHY5-93F-HA-V2" manufactured by JX Metals) was used as the metal foil. Figure 2 As shown, the laminate consists of copper foil / adhesive sheet / adhesive sheet / copper foil. After hot lamination by a hot roller laminating device under the conditions of lamination temperature 360℃, lamination pressure 244N / cm, and lamination speed 1m / min, it is peeled between two adhesive sheets to obtain two single-sided copper-clad laminates.

[0133] [Example 2]

[0134] Using a multilayer polyimide film 1 as an adhesive sheet, such as Figure 4As shown, the laminate is composed of a protective film / copper foil / adhesive sheet / adhesive sheet / copper foil / protective film. After hot lamination under the same conditions as in Example 1 using a hot roller laminating device, two single-sided copper-clad laminates are obtained by peeling between the two adhesive sheets and between the copper foil and the protective film. A non-thermoplastic polyimide film (Kaneka's "Apical125NPI") is used as the surface protective film positioned on the outer side of the upper and lower rolled copper foils.

[0135] [Example 3]

[0136] A single-sided copper-clad laminate was obtained in the same manner as in Example 1, except that a multilayer polyimide film 2 was used as an adhesive sheet.

[0137] [Example 4]

[0138] Except for using a multilayer polyimide film 3 as an adhesive sheet, a single-sided copper-clad laminate was obtained in the same manner as in Example 1.

[0139] [Comparative Example 1]

[0140] Using a multilayer polyimide film 1 as an adhesive sheet, and with the copper foil / adhesive sheet stacked together, a hot lamination was attempted under the same conditions as in Example 1 using a hot roller lamination device. However, the adhesive sheet was attached to the hot roller, and a single-sided copper-clad laminate could not be obtained.

[0141] [Comparative Example 2]

[0142] Using a multilayer polyimide film 1 as an adhesive sheet, a copper foil / adhesive sheet / protective film stack is constructed. After hot lamination under the same conditions as in Example 1 using a hot roller laminating device, the copper foil and the protective film are peeled off to obtain a single-sided copper-clad laminate. As the protective film, a non-thermoplastic polyimide film (Kaneka's "Apical50AH") is used.

[0143] [Comparative Example 3]

[0144] A single-sided copper-clad laminate was obtained in the same manner as in Comparative Example 2, except that a multilayer polyimide film 2 was used as an adhesive sheet.

[0145] [Comparative Example 4]

[0146] A single-sided copper-clad laminate was obtained in the same manner as in Comparative Example 2, except that a multilayer polyimide film 3 was used as an adhesive sheet.

[0147] [Evaluate]

[0148] <Peel strength of copper foil>

[0149] A 1mm wide masking tape was applied to the surface of the copper foil on a single-sided copper-clad laminate. The copper foil was then etched using a ferric chloride aqueous solution to form a 1mm wide copper foil pattern. The peel strength of the copper foil pattern was measured using a tensile testing machine at a peel angle of 90° and a peel speed of 50mm / min.

[0150] <Warp>

[0151] A single-sided copper-clad laminate was cut into 5cm × 5cm squares and placed on a platform with the copper foil-bonded side facing up. The distances (buoyancy) between the square and the platform were measured at each of the four vertices, and the average value was taken as the warpage.

[0152] <Appearance>

[0153] Under fluorescent light, the copper foil side and the adhesive sheet side of the single-sided copper-clad laminate are visually observed. Case A is defined as the case where no wrinkles or stripes are observed on either side, and case B is defined as the case where wrinkles or stripes are observed on either side.

[0154] Table 2 shows the types of adhesive sheets (multilayer polyimide films) used in the examples and comparative examples, their tensile modulus of elasticity at 350°C, their lamination structure during hot lamination, and the evaluation results of single-sided copper-clad laminates.

[0155] [Table 2]

[0156]

[0157] In Comparative Example 1, where a multilayer polyimide film (adhesive sheet) is thermally laminated with a copper foil, the thermoplastic resin layer of the multilayer polyimide film is attached to the hot roller, making it impossible to obtain a single-sided copper-clad laminate. In contrast, in Example 1, where two adhesive sheets are thermally laminated with two copper foils, the thermoplastic resin layer of the multilayer polyimide film does not contact the hot roller, so thermal lamination can be performed without problems.

[0158] The copper-clad laminate of Example 1, obtained by peeling the thermally laminated body at the interface of the two adhesive sheets, exhibits similar high adhesion (peel strength) and low warpage to the copper-clad laminate of Comparative Example 2. The same tendency is also observed in the comparison between Example 3 and Comparative Example 3, and between Example 4 and Comparative Example 4.

[0159] In Example 1, where two adhesive sheets and two copper foils are thermally laminated, the thermoplastic resin layer of the multilayer polyimide film is not in contact with the hot roller, so thermal lamination can be performed without problems. Furthermore, the copper-clad laminate of Example 1, obtained by peeling the thermally laminated body at the interface of the two adhesive sheets, exhibits similar high adhesion (peel strength) and minimal warpage to the copper foil of Comparative Example 2.

[0160] Based on these results, it can be seen that by thermally laminating two adhesive sheets with two metal foils and then peeling them off at the interface of the adhesive layers, single-sided copper-clad laminates with properties equal to or better than those of the previous ones can be obtained with higher productivity.

[0161] No wrinkles or streaks were observed in the single-sided copper-clad laminates of Examples 3 and 4 using multilayer polyimide films 2 and 3. In contrast, the appearance of the single-sided copper-clad laminates of Examples 1 and 2 (and Comparative Example 2) using multilayer polyimide film 1 was worse. It is believed that multilayer polyimide films 2 and 3 have a lower elastic modulus at high temperatures compared to multilayer polyimide film 1, thus providing higher cushioning during hot lamination and suppressing the formation of wrinkles or streaks.

[0162] Explanation of reference numerals in the attached figures

[0163] 1. 101, 102 adhesive sheets (multilayer film)

[0164] 10, 110, 120 core layers

[0165] 11, 12, 111, 112, 121, 122 thermoplastic resin layers

[0166] 5, 151, 152 metal foil

[0167] 20, 121, 121 single-sided metal-clad laminate

[0168] 71 Intermediate Protective Film

[0169] 91, 92 Surface Protective Film

Claims

1. A method for manufacturing a single-sided metal-clad laminate, wherein, This single-sided metal-clad laminate has the following features: An adhesive sheet comprising a core layer formed of a heat-resistant film, a first thermoplastic resin layer disposed on a first main surface of the core layer, and a second thermoplastic resin layer disposed on a second main surface of the core layer; and a metal foil tightly laminated to the first thermoplastic resin layer of the adhesive sheet. The manufacturing method of this single-sided metal-clad laminate includes the following steps: In the lamination process, the first metal foil, the first adhesive sheet, the second adhesive sheet, and the second metal foil are arranged such that the first main surface of the first metal foil faces the first main surface of the first adhesive sheet, the second main surface of the second adhesive sheet faces the second main surface of the first adhesive sheet, and the first main surface of the second metal foil faces the first main surface of the second adhesive sheet, and the first main surface of the second metal foil faces the first main surface of the second adhesive sheet, and then thermally laminated to form a laminate containing the first metal foil, the first adhesive sheet, the second adhesive sheet, and the second metal foil; and The peeling process involves separating the laminate between the first adhesive sheet and the second adhesive sheet. Simultaneously, a first single-sided metal-clad laminate with a first metal foil tightly laminated on the first main surface of the first adhesive sheet and a second single-sided metal-clad laminate with a second metal foil tightly laminated on the first main surface of the second adhesive sheet are obtained. Wherein, the core layer of the first adhesive sheet and the core layer of the second adhesive sheet are non-thermoplastic polyimide films. The first and second thermoplastic resin layers of the first adhesive sheet, and the first and second thermoplastic resin layers of the second adhesive sheet, comprise thermoplastic polyimide resin. The tensile modulus of elasticity of the first adhesive sheet and the second adhesive sheet at a temperature of 350°C is 0.05 to 1.5 GPa.

2. The method for manufacturing a single-sided metal-clad laminate as described in claim 1, wherein, In the lamination process, no other layers are placed on the second main surface of the first metal foil and the second main surface of the second metal foil for thermal lamination.

3. The method for manufacturing a single-sided metal-clad laminate as described in claim 1, wherein, In the lamination process, thermal lamination is performed with a first surface protective film disposed on the second main surface of the first metal foil and a second surface protective film disposed on the second main surface of the second metal foil. In the peeling process, in addition to peeling the first adhesive sheet and the second adhesive sheet, peeling is also performed at the interface between the first metal foil and the first surface protective film, and at the interface between the second metal foil and the second surface protective film.

4. The method for manufacturing a single-sided metal-clad laminate as described in claim 3, wherein, The first surface protective film and the second surface protective film are non-thermoplastic polyimide films.

5. The method for manufacturing a single-sided metal-clad laminate as described in claim 3, wherein, The first surface protective film and the second surface protective film are metal foils.

6. The method for manufacturing a single-sided metal-clad laminate as described in any one of claims 3 to 5, wherein, The thickness of the first surface protective film and the second surface protective film is 25~300μm.

7. The method for manufacturing a single-sided metal-clad laminate as described in any one of claims 3 to 5, wherein, The thickness of the first surface protective film and the second surface protective film is 75~200μm.

8. The method for manufacturing a single-sided metal-clad laminate as described in any one of claims 1 to 5, wherein, In the lamination process, the first adhesive sheet's second thermoplastic resin layer is laminated to the second adhesive sheet's second thermoplastic resin layer. In the peeling process, peeling is performed at the interface between the second thermoplastic resin layer of the first adhesive sheet and the second thermoplastic resin layer of the second adhesive sheet, thereby peeling the first adhesive sheet and the second adhesive sheet apart.

9. The method for manufacturing a single-sided metal-clad laminate as described in any one of claims 1 to 5, wherein, In the lamination process, an intermediate protective film is disposed between the first adhesive sheet and the second adhesive sheet, and the layers are laminated such that the first main surface of the intermediate protective film is in contact with the second thermoplastic resin layer of the first adhesive sheet, and the second main surface of the intermediate protective film is in contact with the second thermoplastic resin layer of the second adhesive sheet. In the peeling process, the second thermoplastic resin layer of the first adhesive sheet and the intermediate protective film are peeled off at the interface between them, and the second thermoplastic resin layer of the second adhesive sheet and the intermediate protective film, thereby peeling the first adhesive sheet and the second adhesive sheet apart.

10. The method for manufacturing a single-sided metal-clad laminate as described in claim 9, wherein, The intermediate protective film is a non-thermoplastic polyimide film.

11. The method for manufacturing a single-sided metal-clad laminate as described in claim 9, wherein, The intermediate protective film is a metal foil.

12. The method for manufacturing a single-sided metal-clad laminate as described in claim 9, wherein, The thickness of the intermediate protective film is 25~300μm.

13. The method for manufacturing a single-sided metal-clad laminate as described in claim 9, wherein, The thickness of the intermediate protective film is 75~200μm.

14. The method for manufacturing a single-sided metal-clad laminate as described in claim 1, wherein, The non-thermoplastic polyimide film comprises non-thermoplastic polyimide resin and filler.

15. The method for manufacturing a single-sided metal-clad laminate as described in any one of claims 1 to 5, wherein, The thickness of the core layer of the first adhesive sheet and the core layer of the second adhesive sheet is 3~50μm.

16. The method for manufacturing a single-sided metal-clad laminate as described in any one of claims 1 to 5, wherein, The thickness of the core layer of the first adhesive sheet and the core layer of the second adhesive sheet is 5~40μm.

17. The method for manufacturing a single-sided metal-clad laminate as described in claim 1, wherein, The thermoplastic polyimide resin comprises one or more tetracarboxylic dianhydrides selected from the group consisting of benzophenone tetracarboxylic dianhydride, biphenyl tetracarboxylic dianhydride, oxydiphthalic dianhydride and biphenyl sulfone tetracarboxylic dianhydride, and contains an aromatic diamine having an aminophenoxy group as a diamine.

18. The method for manufacturing a single-sided metal-clad laminate as described in claim 17, wherein, In the thermoplastic polyimide resin, the proportion of p-phenylenediamine in the diamine is less than 40 mol%.

19. The method for manufacturing a single-sided metal-clad laminate as described in claim 17, wherein, In the thermoplastic polyimide resin, the proportion of p-phenylenediamine in the diamine is less than 20 mol%.

20. The method for manufacturing a single-sided metal-clad laminate as described in any one of claims 1 to 5, wherein, The glass transition temperatures of the first thermoplastic resin layer and the second thermoplastic resin layer of the first adhesive sheet, and the first thermoplastic resin layer and the second thermoplastic resin layer of the second adhesive sheet, are 150~320℃.

21. The method for manufacturing a single-sided metal-clad laminate as described in any one of claims 1 to 5, wherein, The glass transition temperatures of the first thermoplastic resin layer and the second thermoplastic resin layer of the first adhesive sheet, and the first thermoplastic resin layer and the second thermoplastic resin layer of the second adhesive sheet, are 200~300℃.

22. The method for manufacturing a single-sided metal-clad laminate as described in any one of claims 1 to 5, wherein, The thickness of the first thermoplastic resin layer and the second thermoplastic resin layer of the first adhesive sheet, and the thickness of the first thermoplastic resin layer and the second thermoplastic resin layer of the second adhesive sheet are 0.5~15μm.

23. The method for manufacturing a single-sided metal-clad laminate as described in any one of claims 1 to 5, wherein, The thickness of the first thermoplastic resin layer and the second thermoplastic resin layer of the first adhesive sheet, and the thickness of the first thermoplastic resin layer and the second thermoplastic resin layer of the second adhesive sheet are 1~10μm.

24. The method for manufacturing a single-sided metal-clad laminate as described in any one of claims 1 to 5, wherein, In each of the first adhesive sheet and the second adhesive sheet, the thickness of the first thermoplastic resin layer and the second thermoplastic resin layer is 0.05 to 0.5 times the thickness of the core layer.

25. The method for manufacturing a single-sided metal-clad laminate as described in any one of claims 1 to 5, wherein, In each of the first adhesive sheet and the second adhesive sheet, the thickness of the first thermoplastic resin layer and the second thermoplastic resin layer is 0.1 to 0.4 times the thickness of the core layer.

26. The method for manufacturing a single-sided metal-clad laminate as described in any one of claims 1 to 5, wherein, In each of the first adhesive sheet and the second adhesive sheet, the thickness of the first thermoplastic resin layer is 0.7 to 1.3 times the thickness of the second thermoplastic resin layer.

27. The method for manufacturing a single-sided metal-clad laminate as described in any one of claims 1 to 5, wherein, In each of the first adhesive sheet and the second adhesive sheet, the thickness of the first thermoplastic resin layer is 0.9 to 1.1 times the thickness of the second thermoplastic resin layer.

28. The method for manufacturing a single-sided metal-clad laminate as described in any one of claims 1 to 5, wherein, The tensile modulus of elasticity of the first adhesive sheet and the second adhesive sheet at a temperature of 350°C is 0.14 to 0.5 GPa.

29. The method for manufacturing a single-sided metal-clad laminate as described in any one of claims 1 to 5, wherein, The first metal foil and the second metal foil are copper foils.

30. The method for manufacturing a single-sided metal-clad laminate as described in any one of claims 1 to 5, wherein, The thickness of the first metal foil and the second metal foil is 3~30μm.

31. The method for manufacturing a single-sided metal-clad laminate as described in any one of claims 1 to 5, wherein, The thickness of the first metal foil and the second metal foil is 5~20μm.

32. The method for manufacturing a single-sided metal-clad laminate as described in any one of claims 1 to 5, wherein, The surface roughness Rz of the first main surface of the first metal foil and the second metal foil is 0.01 μm to 1 μm.

33. The method for manufacturing a single-sided metal-clad laminate as described in any one of claims 1 to 5, wherein, In the lamination process, hot lamination is performed in a roller-to-roll manner.

34. The method for manufacturing a single-sided metal-clad laminate as described in any one of claims 1 to 5, wherein, In the lamination process, the heating temperature during hot lamination is above the glass transition temperature of the first thermoplastic resin layer and the second thermoplastic resin layer of the first adhesive sheet, and the first thermoplastic resin layer and the second thermoplastic resin layer of the second adhesive sheet.

35. The method for manufacturing a single-sided metal-clad laminate as described in any one of claims 1 to 5, wherein, In the lamination process, the heating temperature during hot lamination is 280~400℃.

36. The method for manufacturing a single-sided metal-clad laminate as described in any one of claims 1 to 5, wherein, In the lamination process, the heating temperature during hot lamination is 320~370℃.

Images