Laminate and manufacturing method thereof

Abstract

To provide a laminate which has a smooth interface between an insulating base material having a thermoplastic resin on an outermost surface layer and a metal layer formed on the insulating base material, and has excellent adhesion between the insulator and the metal layer, a method for manufacturing the same, and a printed wiring board manufactured using the laminate.SOLUTION: The inventors have found out a laminate having excellent adhesion by using a laminate in which a thermoplastic resin layer (B), a primer layer (C) and a metal layer (D) are laminated sequentially on an insulating base material (A).SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a laminate that can be used for printed wiring boards and flexible printed wiring boards, and a method for producing the same. [Background technology]

[0002] The miniaturization, increased speed, and increased frequency of electronic devices are driving demands for higher density, lower transmission loss, and other performance improvements in printed wiring boards. To meet these demands, insulating substrates used in printed wiring boards are becoming increasingly heat-resistant and low-dielectric. The basic structure of a printed wiring board is an insulating substrate with a circuit pattern conductor formed on its surface. A technology is required to properly bond the conductor to the insulating substrate. However, insulating substrates with high heat resistance and low dielectric constant often exhibit poor adhesion to the copper conductor. Therefore, a widely used method for manufacturing printed wiring board substrates with good adhesion is to use a high-heat-resistant, low-dielectric insulating substrate as a core layer, form a thermoplastic surface layer, and then laminate a roughened copper foil under heat and pressure. Meanwhile, low-dielectric materials are generally thermoplastic, and low-dielectric materials alone may not be suitable for use as printed wiring board substrates. Therefore, a known method involves forming a thermoplastic low-dielectric material on the surface of a non-thermoplastic core material, thereby achieving low dielectricity while maintaining substrate processability. In this case, the thermoplastic surface layer plays a role in reducing the dielectric constant of the substrate and ensuring adhesion by laminating the roughened copper foil. As such, insulating substrates having a thermoplastic surface layer have been attracting attention as substrates for high-performance printed wiring boards. However, in conventional methods of laminating roughened copper foil, unevenness originating from the copper foil is formed at the adhesive interface between the insulating substrate and the conductor, which poses challenges in increasing circuit density and suppressing signal transmission loss in the high-frequency band.

[0003] As a method for ensuring smoothness at the interface between the substrate and the conductor, a method has been proposed in which a thin metal film is formed on the surface of the insulating substrate by vapor deposition or sputtering, and then the thin metal film is used as a seed to thicken the film by plating (Patent Document 1). However, this method has problems such as the need to use a magnetic metal such as nickel at the insulator-conductor interface, which increases transmission loss, and the insulator-conductor interface not being able to provide sufficient adhesion.

[0004] Therefore, there has been a demand for a laminate that has a smooth interface between the insulating substrate and the conductor and has sufficient adhesion as a substrate for a high-performance printed wiring board. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2015-118044 Summary of the Invention [Problem to be solved by the invention]

[0006] The problem to be solved by the present invention is to provide a laminate in which the interface between an insulating substrate having a thermoplastic resin as the outermost layer and a metal layer formed thereon is smooth and the insulator-metal layer has excellent adhesion, a method for producing the same, and a printed wiring board produced using the laminate. [Means for solving the problem]

[0007] As a result of intensive research to solve the above-mentioned problems, the present inventors have found that the above-mentioned problems can be solved by a laminate in which a thermoplastic resin layer, a primer layer, and a metal layer are sequentially laminated on an insulating substrate, and have completed the present invention.

[0008] That is, the present invention provides: 1. A laminate comprising an insulating substrate (A) and a thermoplastic resin layer (B), a primer layer (C), and a metal layer (D) laminated in this order on the insulating substrate (A). 2. The laminate according to 1, wherein the metal layer (D) comprises a plating layer (d2) laminated on a plating base layer (d1). 3. The laminate according to 2, wherein the plating underlayer (d1) is selected from at least one of a porous metal layer, a continuous metal layer, or a mixed metal layer of a porous and continuous metal layer. 4. The laminate according to 3, wherein the porous film is a layer made of metal particles. 5. The laminate according to 4, wherein the metal particles constituting the porous film are coated with a polymer dispersant. 6. The laminate according to any one of 1 to 5, wherein the thermoplastic resin layer (B) and the primer layer (C) form a mixed layer (E). 7. The laminate according to any one of 1 to 6, wherein the thermoplastic resin layer (B) is a layer containing at least one resin selected from the group consisting of polyimide resin and fluorine-containing resin as a main component. 8. The laminate according to any one of 1 to 7, wherein the primer layer (C) is a layer containing a primer resin (c1) and inorganic particles (c2). 9. The laminate according to 8, wherein the primer resin (c1) is a resin having a reactive functional group [X], the polymer dispersant has a reactive functional group [Y], and the reactive functional group [X] and the reactive functional group [Y] can form a bond with each other by reaction. 10. The laminate according to 9, wherein the polymer dispersant having the reactive functional group [Y] is at least one selected from the group consisting of polyalkyleneimine and polyalkyleneimine having a polyoxyalkylene structure containing an oxyethylene unit. 11. The laminate according to 9, wherein the reactive functional group [X] is at least one selected from the group consisting of a keto group, an acetoacetyl group, an epoxy group, a carboxyl group, an N-alkylol group, an isocyanate group, a vinyl group, a (meth)acryloyl group, and an allyl group. 12. A printed wiring board produced using the laminate according to any one of 1 to 11. 13. Step (1) of forming the thermoplastic resin layer (B) on the insulating substrate (A); a step (2) of forming the primer layer (C) on the thermoplastic resin layer (B); Furthermore, a step (3) of forming the metal layer (D) on the primer layer (C); 12. The method for producing a laminate according to any one of 1 to 11, comprising: 14. A step (2) of forming the primer layer (C) on a substrate having the thermoplastic resin layer (B) on an insulating substrate (A), and further a step (3) of forming the metal layer (D) on the primer layer (C); 12. The method for producing a laminate according to any one of 1 to 11, comprising: 15. The step of forming the metal layer (D) on the primer layer (C) 15. The method for producing a laminate according to 13 or 14, characterized in that it comprises a step (3-1) of forming a plating underlayer (d1) and a step (3-2) of forming a plating layer (d2). 16. A method for producing a laminate according to 15, characterized in that after step (2) of forming the primer layer (C), a step of performing heat treatment at a temperature equal to or higher than the softening temperature of the thermoplastic resin layer (B) is included. 17. The method for producing a laminate according to claim 15, characterized in that after the step (3-1) of forming the plating base layer (d1), a step of performing heat treatment at a temperature equal to or higher than the softening temperature of the thermoplastic resin layer (B) is included. 18. The method for producing a laminate according to 15, further comprising the step of performing heat treatment at a temperature equal to or higher than the softening temperature of the thermoplastic resin layer (B) after the step (3-2) of forming the plating layer (d2). This provides: [Effects of the Invention]

[0009] The laminate of the present invention is a laminate in which a metal layer is laminated with a smooth interface on an insulating substrate having a thermoplastic resin as the outermost layer, and the laminate has excellent adhesion between the insulating substrate and the metal layer. rBy using an insulating substrate in which a thermoplastic layer is formed on a low-dielectric core layer having a low dielectric constant and a low dielectric loss tangent tanδ, or an insulating substrate having a low-dielectric thermoplastic resin as the outermost layer, it is possible to provide a laminate for forming a printed wiring board with low transmission loss in which dielectric loss and conductor loss are suppressed.

[0010] Furthermore, by patterning the metal layer, the laminate of the present invention can be suitably used as electronic components such as printed wiring boards, flexible printed wiring boards, conductive films for touch panels, metal meshes for touch panels, organic solar cells, organic EL elements, organic transistors, RFID such as contactless IC cards, electromagnetic wave shields, LED lighting substrates, digital signage, etc. In particular, laminates using low-dielectric materials are ideal for printed wiring board applications that suppress transmission loss in high-frequency bands that can be used in fifth-generation communication systems (5G) and next-generation communication systems (beyond 5G). DETAILED DESCRIPTION OF THE INVENTION

[0011] The laminate of the present invention comprises an insulating substrate (A) on which a thermoplastic resin layer (B), a primer layer (C), and a metal layer (D) are sequentially laminated.

[0012] The laminate of the present invention may be a laminate in which a thermoplastic resin layer (B) and the like are sequentially laminated on one side of the insulating substrate (A), or may be a laminate in which a thermoplastic resin layer (B) and the like are sequentially laminated on both sides of the insulating substrate (A).

[0013] In the laminate of the present invention, the insulating substrate (A) and the thermoplastic resin layer (B) laminated thereon may have a clear interface in terms of composition, or the two components may be mutually mixed in the interface region, and may not have a clear interface.

[0014] The insulating substrate (A) may be made of, for example, polyimide, transparent polyimide, polyamideimide, polyamide, polyethylene terephthalate, polyethylene naphthalate, polycarbonate, acrylonitrile-butadiene-styrene (ABS) resin, a polymer alloy of ABS and polycarbonate, an acrylic resin such as polymethyl (meth)acrylate, polytetrafluoroethylene, tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer, tetrafluoroethylene-hexafluoropropylene copolymer, tetrafluoroethylene-ethylene copolymer, vinylidene fluoride resin, trifluorochloroethylene resin, trifluorochloroethylene-ethylene copolymer, tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer, vinylidene fluoride resin ... Examples include insulating substrates made of ethylene fluoride-perfluorodioxol copolymer, vinyl fluoride resin, polyvinylidene fluoride, polyvinyl chloride, polyvinylidene chloride, polyvinyl alcohol, polycarbonate, polyethylene, polypropylene, polyurethane, liquid crystal polymer (LCP), polyether ether ketone (PEEK), polyphenylene sulfide (PPS), polyphenylene sulfone (PPSU), epoxy resin, cellulose nanofiber, silicon, ceramics, glass, etc., porous substrates made of these materials, and insulating substrates whose surfaces have been vapor-deposited with silicon carbide or diamond-like carbon.

[0015] Furthermore, when the laminate of the present invention is used for a printed wiring board or the like, it is preferable to use an insulating substrate made of polyimide, transparent polyimide, polytetrafluoroethylene, tetrafluoroethylene-ethylene copolymer, polyethylene terephthalate, polyethylene naphthalate, liquid crystal polymer (LCP), polyether ether ketone (PEEK), glass, cellulose nanofiber, or the like, with polyimide being particularly preferred.

[0016] Furthermore, when the laminate of the present invention is used for a flexible printed wiring board or the like, the insulating substrate is preferably a film-like or sheet-like insulating substrate having flexibility that allows bending.

[0017] When the insulating substrate is in the form of a film or sheet, the thickness thereof is generally preferably in the range of 1 to 5000 μm, more preferably in the range of 1 to 300 μm, and even more preferably in the range of 1 to 200 μm.

[0018] The thermoplastic resin layer (B) is not particularly limited, and examples thereof include polyolefin resins, vinyl resins, styrene-acrylic resins, diene resins, terpene resins, petroleum resins, cellulose resins, polyamide resins, polyurethane resins, polyester resins, polycarbonate resins, polyimide resins, liquid crystal polymers, fluororesins, etc. These resins can be used alone or in combination of two or more.

[0019] When the laminate of the present invention is used to form a printed wiring board for high-frequency signal transmission, the resin forming the thermoplastic resin layer (B) is preferably one having a dielectric constant of 3.5 or less and a dielectric loss tangent of 0.006 or less at 10 GHz as a laminate of the insulating substrate (A) and the thermoplastic resin layer (B). The dielectric constant is more preferably 3.0 or less, and particularly preferably 2.8 or less. The dielectric loss tangent is more preferably 0.004 or less, and particularly preferably 0.003 or less. In other words, the thermoplastic resin layer is preferably a thermoplastic polyimide layer or a thermoplastic fluororesin layer that can achieve the above-mentioned dielectric constant and dielectric loss tangent.

[0020] The thickness of the thermoplastic resin layer (B) is preferably in the range of 1 to 50 μm, more preferably in the range of 3 to 40 μm, and even more preferably in the range of 3 to 30 μm.

[0021] The thermoplastic polyimide layer is obtained by imidizing a thermoplastic polyamic acid, which is a precursor of the thermoplastic polyimide, and can be synthesized using a diamine and an acid dianhydride, which are raw materials commonly used in the synthesis of polyamic acid.

[0022] The diamine is not particularly limited, but aromatic diamines are preferred in terms of heat resistance, etc. Examples include 2,2′-bis[4-(4-aminophenoxy)phenyl]propane, 4,4′-diaminodiphenylpropane, 4,4′-diaminodiphenylmethane, 4,4′-diaminodiphenyl sulfide, 3,3′-diaminodiphenyl sulfone, 4,4′-diaminodiphenyl sulfone, 4,4′-oxydianiline, 3, Examples of the alkylaminobenzophenone include 3'-oxydianiline, 3,4'-oxydianiline, 4,4'-diaminodiphenyldiethylsilane, 4,4'-diaminodiphenylsilane, 4,4'-diaminodiphenylethylphosphine oxide, 4,4'-diaminodiphenyl N-methylamine, 4,4'-diaminodiphenyl N-phenylamine, 1,4-diaminobenzene (p-phenylenediamine), bis{4-(4-aminophenoxy)phenyl}sulfone, bis{4-(3-aminophenoxy)phenyl}sulfone, 4,4'-bis(4-aminophenoxy)biphenyl, 4,4'-bis(3-aminophenoxy)biphenyl, 1,3-bis(3-aminophenoxy)benzene, 1,3-bis(3-aminophenoxy)benzene, 3,3'-diaminobenzophenone, 4,4'-diaminobenzophenone, and 2,2-bis(4-aminophenoxyphenyl)propane. These resins can be used alone or in combination of two or more.

[0023] The acid dianhydride is not particularly limited, but aromatic acid dianhydrides are preferred in terms of heat resistance, etc. Examples thereof include pyromellitic dianhydride, 2,3,6,7-naphthalenetetracarboxylic dianhydride, 3,3',4,4'-biphenyltetracarboxylic dianhydride, 1,2,5,6-naphthalenetetracarboxylic dianhydride, 2,2',3,3'-biphenyltetracarboxylic dianhydride, 3,3',4,4'-benzophenonetetracarboxylic dianhydride, 2,2',3,3'-benzophenonetetracarboxylic dianhydride, 4,4'-oxyphthalic dianhydride, 3,4'-oxyphthalic dianhydride, 2,2-bis(3,4-dicarboxyphenyl)propanoic dianhydride, 3,4,9,10-perylenetetracarboxylic dianhydride, bis(3 ,4-dicarboxyphenyl)propanoic dianhydride, 1,1-bis(2,3-dicarboxyphenyl)ethane dianhydride, 1,1-bis(3,4-dicarboxyphenyl)ethane dianhydride, bis(2,3-dicarboxyphenyl)methane dianhydride, bis(3,4-dicarboxyphenyl)ethane dianhydride, oxydiphthalic dianhydride, bis(3,4-dicarboxyphenyl)sulfonic dianhydride, p-phenylene bis(trimellitic acid monoester anhydride), ethylene bis(trimellitic acid monoester anhydride), bisphenol A bis(trimellitic acid monoester anhydride), and the like.

[0024] The thermoplastic fluororesin layer is made up of 50% by mass or more, more preferably 90% by mass or more, and even more preferably 99% by mass or more of the components constituting the fluororesin layer. The fluororesin is a resin having a bond between a carbon atom (C) and a fluorine atom (F) in the molecular chain.

[0025] The fluorine-containing resin is not particularly limited, but examples thereof include tetrafluoroethylene-hexafluoropropylene copolymer (FEP: Fluorinated ethylenepropylene), tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA: Perfluoroalkane), polytetrafluoroethylene (PTFE: Polytetrafluoroethylene) or tetrafluoroethylene-perfluorodioxol copolymer (TFE / PDD: Tetrafluoroethylene-Perfluorodioxol copolymer), polyvinylidene fluoride, polychlorotrifluoroethylene, chlorotrifluoroethylene-ethylene copolymer, polyvinyl fluoride, tetrafluoroethylene-hexafluoropropylene-vinylidene fluoride terpolymer, fluoroelastomer, etc. Furthermore, mixtures containing two or more of these compounds and copolymers formed by combining two or more of the respective monomers constituting these fluorine-containing resins are also included.

[0026] When the laminate of the present invention is used for a printed wiring board, a flexible printed wiring board, or the like, it is preferable to use FEP, PFA, PTFE, or TFE / PDD as the fluorine-containing resin layer of the insulating substrate (A) having the fluorine-containing resin layer.

[0027] When the laminate of the present invention is used for a printed wiring board, a flexible printed wiring board, or the like, it is preferable to use FEP, PFA, PTFE, or TFE / PDD as the fluorine-containing resin layer of the insulating substrate (A) having the fluorine-containing resin layer.

[0028] The fluorine-containing resin may contain a polar group containing at least one of oxygen and nitrogen. Such a polar group is not particularly limited, but is preferably at least one selected from the group consisting of a carboxy (-COOH) group, a carboxylic anhydride (-CO-O-CO-) group, an alkoxycarbonyl (RCOO- (R is a monovalent hydrocarbon group)) group, a hydroxy (-OH) group, an epoxy group, and an isocyanate (-N=C=O) group.

[0029] In the present invention, a thermoplastic resin layer (B), a primer layer (C), and a metal layer (D) are sequentially laminated on an insulating substrate (A). The thermoplastic resin layer (B) may be formed on the insulating substrate (A) before use, or a substrate having a thermoplastic resin layer (B) formed on the insulating substrate (A) in advance may be used.

[0030] The method for forming the thermoplastic resin layer (B) on the insulating substrate (A) is not particularly limited, and examples thereof include a method in which a solution containing a thermoplastic resin precursor or a thermoplastic resin is applied to the insulating substrate (A) and then heat-treated; a method in which a pre-formed thermoplastic resin film is superimposed on the insulating substrate (A) and heat-pressed; and a method in which a thermoplastic resin composition is melted and extruded into a film and then laminated on the insulating substrate (A).

[0031] As a substrate on which a thermoplastic resin layer (B) is previously formed on an insulating substrate (B), for example, the PIXIO series manufactured by Kaneka Corporation or Upilex VT and NVT manufactured by Ube Industries, Ltd., which have a thermoplastic polyimide layer, can be suitably used.

[0032] As a method for forming the thermoplastic resin layer (B) on the insulating substrate (A), for example, a method for forming a polyimide resin thermoplastic layer (B) on the insulating substrate (A) can be formed with reference to, for example, JP 2019-14062 A. Furthermore, a fluorine-containing resin thermoplastic resin layer (B) can be formed with reference to, for example, JP 2019-166844 A.

[0033] Before forming the primer layer (C) described below, the thermoplastic resin layer (B) may be subjected to a surface treatment, if necessary, to a degree that does not impair surface smoothness. Specific examples include dry treatments such as corona treatment, plasma treatment, and ultraviolet treatment, and wet treatments using ozone water, aqueous solutions of acids and alkalis, or organic solvents. By performing an appropriate surface treatment, it is possible to remove dirt adhering to the surface that may inhibit the formation of the primer layer (C), and to introduce functional groups such as hydroxyl groups, carbonyl groups, and carboxyl groups into the surface of the thermoplastic resin layer (B), thereby further improving adhesion between the thermoplastic resin layer (B) and the primer layer (C).

[0034] The primer layer (C) is a layer containing a primer resin (c1), and a preferred embodiment thereof is a layer containing the primer resin (c1) and inorganic particles (c2).

[0035] Examples of materials constituting the primer resin (c1) include urethane resins, acrylic resins, core-shell composite resins with a urethane resin shell and an acrylic resin core, epoxy resins, imide resins, amide resins, melamine resins, phenolic resins, urea-formaldehyde resins, blocked isocyanate polyvinyl alcohol obtained by reacting polyisocyanate with a blocking agent such as phenol, and polyvinylpyrrolidone. Core-shell composite resins with a urethane resin shell and an acrylic resin core can be obtained, for example, by polymerizing acrylic monomers in the presence of a urethane resin. These resins can be used alone or in combination of two or more.

[0036] When the plating underlayer (d1) described below is formed of metal particles and a dispersant for the metal particles has a reactive functional group [Y], the resin constituting the primer resin (c1) is preferably a resin having a reactive functional group [X] that is reactive with the reactive functional group [Y]. Examples of the reactive functional group [X] include an amino group, an amide group, an alkylolamide group, a keto group, a carboxyl group, a carboxyl anhydride group, a carbonyl group, an acetoacetyl group, an epoxy group, an alicyclic epoxy group, an oxetane ring, a vinyl group, an allyl group, a (meth)acryloyl group, a (blocked) isocyanate group, and an (alkoxy)silyl group.

[0037] Among the resins that form the primer resin (c1), it is preferable to use one that contains an aminotriazine-modified novolak resin (c1-1).

[0038] The aminotriazine-modified novolak resin (c1-1) is a novolak resin in which an aminotriazine ring structure and a phenol structure are bonded via a methylene group. The aminotriazine-modified novolak resin (c1-1) can be obtained, for example, by co-condensing an aminotriazine compound such as melamine, benzoguanamine, or acetoguanamine with a phenol compound such as phenol, cresol, butylphenol, bisphenol A, phenylphenol, naphthol, or resorcinol and formaldehyde at near-neutral pH in the presence or absence of a weak alkaline catalyst such as an alkylamine, or by reacting an alkyl ether of an aminotriazine compound such as methyl-etherified melamine with the phenol compound.

[0039] The aminotriazine-modified novolak resin (c1-1) preferably has substantially no methylol groups. The aminotriazine-modified novolak resin (c1-1) may contain a molecule in which only the aminotriazine structure is methylene-bonded, a molecule in which only the phenol structure is methylene-bonded, or the like, which is generated as a by-product during the production of the aminotriazine-modified novolak resin (c1-1). Furthermore, the aminotriazine-modified novolak resin (c1-1) may contain a small amount of unreacted raw materials.

[0040] Examples of the phenol structure include a phenol residue, a cresol residue, a butylphenol residue, a bisphenol A residue, a phenylphenol residue, a naphthol residue, and a resorcinol residue. The term "residue" as used herein refers to a structure in which at least one hydrogen atom bonded to a carbon atom of an aromatic ring has been removed. For example, in the case of phenol, this refers to a hydroxyphenyl group.

[0041] Examples of the triazine structure include structures derived from aminotriazine compounds such as melamine, benzoguanamine, and acetoguanamine.

[0042] The phenol structure and the triazine structure can be used alone or in combination of two or more. Furthermore, since adhesion can be further improved, the phenol structure is preferably a phenol residue, and the triazine structure is preferably a structure derived from melamine.

[0043] The hydroxyl value of the aminotriazine-modified novolak resin (c1-1) is preferably in the range of 50 to 200 mgKOH / g, more preferably in the range of 80 to 180 mgKOH / g, and even more preferably in the range of 100 to 150 mgKOH / g, because this can further improve adhesion.

[0044] The aminotriazine-modified novolak resin (c1-1) can be used alone or in combination of two or more kinds.

[0045] When an aminotriazine-modified novolak resin (c1-1) is used as the compound having an aminotriazine ring, it is preferable to use an epoxy resin (c1-2) in combination.

[0046] Examples of the epoxy resin (c1-2) include bisphenol A epoxy resins, bisphenol F epoxy resins, biphenyl epoxy resins, cresol novolac epoxy resins, phenol novolac epoxy resins, bisphenol A novolac epoxy resins, alcohol ether epoxy resins, tetrabromobisphenol A epoxy resins, naphthalene epoxy resins, phosphorus-containing epoxy compounds having a structure derived from a 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide derivative, epoxy resins having a structure derived from a dicyclopentadiene derivative, and epoxidized products of fats and oils such as epoxidized soybean oil. These epoxy resins can be used alone or in combination of two or more.

[0047] Among the epoxy resins (c1-2), bisphenol A type epoxy resins, bisphenol F type epoxy resins, biphenyl type epoxy resins, cresol novolac type epoxy resins, phenol novolac type epoxy resins, and bisphenol A novolac type epoxy resins are preferred because they can further improve adhesion, and bisphenol A type epoxy resins are particularly preferred.

[0048] The epoxy equivalent of the epoxy resin (c1-2) is preferably in the range of 100 to 300 g / equivalent, more preferably in the range of 120 to 250 g / equivalent, and even more preferably in the range of 150 to 200 g / equivalent, since this can further improve adhesion.

[0049] When the primer layer (C) is a layer containing an aminotriazine-modified novolac resin (c1-1) and an epoxy resin (c1-2), the molar ratio [(x) / (y)] of the phenolic hydroxyl group (x) in the aminotriazine-modified novolac resin (c1-1) to the epoxy group (y) in the epoxy resin (c1-2) is preferably in the range of 0.1 to 5, more preferably in the range of 0.2 to 3, and even more preferably in the range of 0.3 to 2, in order to further improve adhesion.

[0050] A curing accelerator may be used in combination to accelerate the reaction between the aminotriazine-modified novolak resin (c1-1) and the epoxy resin (c1-2). Examples of the curing accelerator include amine compounds having a primary, secondary, or tertiary amino group. The amine compound may be any of aliphatic, alicyclic, and aromatic compounds. The curing accelerator may also include mercaptans, acid anhydrides, boron acid fluorides, boric acid esters, organic acid hydrazides, Lewis acids, organometallic compounds, onium salts, and cationic compounds.

[0051] Examples of the inorganic particles (c2) include silica, whiskers made of zinc oxide, calcium carbonate, aluminum silicate, talc, alumina, barium sulfate, magnesium hydroxide, aluminum hydroxide, aluminum sulfate, molybdenum sulfide, etc. The inorganic filler may be in various forms such as particulate, fibrous, needle-like, or flake-like.

[0052] Among the inorganic particles (c2), silica is preferably used. Silica can be produced by a natural method using natural raw materials or a synthetic method using chemical synthesis, but silica obtained by either method can be used. Silica particles dispersed in water or an organic solvent can also be used, and a slurry or colloidal solution in which silica particles are dispersed in advance can also be used.

[0053] In addition, for the purpose of imparting silica particles with dispersibility and affinity with solvents and resins to be compounded, it is more preferable to use silica particles that have been reacted with a silane coupling agent on their surface or that have been attached with a resin as a dispersant.The silane coupling agent is not particularly limited, but examples thereof include epoxy silane, amino silane, vinyl silane, methacryl silane, mercapto silane, etc.In addition, examples of resins that can be used as dispersants for silica particles include acrylic resin, epoxy resin, urethane resin, polyester resin, etc.

[0054] When used in electronics applications, the silica preferably contains few impurities, such as sodium ions, potassium ions, iron ions, aluminum ions, and chloride ions.

[0055] The silica is not particularly limited, but examples of commercially available products that can be used include the SFP series and UFP series (UFP-30, UFP-40, SFP-20M, SFP-30M, SFP-130MC, SFP-120MC, SFP-120MC, SFP-30MHE, UFP-30HH) manufactured by a synthetic method by Denka Co., Ltd., the FB series (FB-5D, FB-8S, FB-15D, FB-20D, FB-40R) manufactured by a natural method, and water-soluble silica manufactured by Nissan Chemical Co., Ltd. The Snowtex series (ST-XS, ST-OXS, ST-NXS, ST-CXS, ST-S, ST-OS, ST-NS, ST-30, ST-O, ST-N, ST-C, ST-AK, ST-50-T, ST-O-40, ST-CM, ST-30L, ST-OL, ST-AK-L, ST-YL, ST-OYL, ST-AK-YL, ST-ZL, MP-1040, MP-2040, MP-4540M, ST-UP, ST-OUP, ST-PS-S, ST-PS- SO, ST-PS-M, ST-PS-MO), and the organosilica sol series, which is a colloidal solution using an organic solvent as a dispersion medium (methanol silica sol, MA-ST-M, MA-ST-L, IPA-ST, IPA-ST-L, IPAST-ZL, IPA-ST-UP, EG-ST, NPC-ST-30, PGM-ST, DMAC-ST, MEK-ST-40, MEK-ST-L, MEK-ST-ZL, MEK-ST-UP, MIBK-ST-L, CHO-ST-M, EAC-ST, PMA-ST, T OL-ST, MEK-AC-2140Z, MEK-AC-4130Y, MEK-AC5140Z, PMG-AC2140Y, PGM-AC-4130Y, MIBK-AC-2140Z, MIBK-SD-L, MEK-EC-2130Y, EP-M2130Y; SO-C type (SO-C1, SO-C2, SO-C4, SO-C5, SO-C6) and SO-E type (SO-E1, SO-E2, SO-E3, SO-E4, SO-E5, SO-E6) manufactured by Admatechs Co., Ltd.

[0056] In order to further improve adhesion, the content of the inorganic particles (c2) in the primer layer (C) is preferably in the range of 1 to 300 parts by mass, more preferably in the range of 3 to 200 parts by mass, and even more preferably in the range of 3 to 150 parts by mass, relative to 100 parts by mass of the primer resin (c1).

[0057] The average particle size of the inorganic particles (c2) is preferably in the range of 0.001 to 0.5 μm, more preferably in the range of 0.01 to 0.3 μm, and even more preferably in the range of 0.01 to 0.1 μm, because this can further improve adhesion. The average particle size is a volume average value measured by diluting the inorganic particles (c2) with a good dispersion solvent and measuring it by dynamic light scattering.

[0058] A primer composition (c) is used to form the primer layer (C). The primer composition (c) contains the primer resin (c1) and inorganic particles (c2), and may further contain a crosslinking agent (c3) as needed. The crosslinking agent (c3) is preferably a polycarboxylic acid. Examples of the polycarboxylic acid include trimellitic anhydride, pyromellitic anhydride, maleic anhydride, and succinic acid. These crosslinking agents (c3) can be used alone or in combination of two or more. Among these crosslinking agents (c3), trimellitic anhydride is preferred because it can further improve adhesion.

[0059] Furthermore, the primer composition (c) used to form the primer layer (C) may contain, as necessary, other resins (c4) as components other than the above components (c1) to (c3). Examples of the other resins (c4) include urethane resins, acrylic resins, blocked isocyanate resins, melamine resins, and phenolic resins. These other resins (c4) can be used alone or in combination of two or more.

[0060] In addition, it is preferable to blend an organic solvent into the primer composition (c) so that the viscosity is suitable for easy application when the primer composition (c) is applied to the thermoplastic resin layer (B). Examples of the organic solvent include toluene, ethyl acetate, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, isopropyl alcohol, diacetone alcohol, ethylene glycol, and toluene. These solvents can be used alone or in combination of two or more.

[0061] The amount of the organic solvent used is preferably adjusted appropriately depending on the coating method used when coating the thermoplastic resin layer (B) described below and the desired film thickness of the primer layer (C).

[0062] Furthermore, known additives such as film-forming aids, leveling agents, thickeners, water repellents, antifoaming agents, and antioxidants may be added to the primer composition (c) as needed.

[0063] The primer layer (C) can be formed by applying the primer composition (c) to a part or the entire surface of the thermoplastic resin layer (B) and then removing the organic solvent contained in the primer composition (c).

[0064] Examples of methods for applying the primer composition (c) to the surface of the thermoplastic resin layer (B) include gravure printing, offset printing, flexography, pad printing, gravure offset printing, letterpress printing, letterpress reversal printing, screen printing, microcontact printing, reverse printing, air doctor coater printing, blade coater printing, air knife coater printing, squeeze coater printing, impregnation coater printing, transfer roll coater printing, kiss coater printing, cast coater printing, spray coater printing, inkjet printing, die coater printing, spin coater printing, bar coater printing, and dip coater printing.

[0065] After the primer composition (c) is applied to the surface of the thermoplastic resin layer (B), the organic solvent contained in the coating layer can be removed by, for example, drying using a dryer to volatilize the organic solvent. The drying temperature may be set within a range that can volatilize the organic solvent used and does not cause adverse effects such as thermal deformation on the thermoplastic resin layer (B).

[0066] The thickness of the primer layer (C) formed using the primer composition (c) may be appropriately selected depending on the application of the laminate of the present invention, but it is preferably in a range that further improves adhesion between the thermoplastic resin layer (B) and the metal layer (D) described below, and is also preferably thin in order to minimize the effect on the dielectric constant and dielectric loss tangent of the laminate. For these reasons, the thickness of the primer layer (C) is preferably in the range of 10 nm to 30 μm, more preferably in the range of 50 nm to 5 μm, and even more preferably in the range of 100 nm to 1 μm.

[0067] The thermoplastic resin layer (B) and the primer layer (C) may have a layer structure in which each layer is laminated in order, or may form a mixed layer (E) in which the components of each layer are distributed in a gradient manner without a clear boundary. Furthermore, in order to further improve adhesion to the metal layer, a mixed layer (E) in which functional groups of the thermoplastic resin layer (B) and functional groups of the primer layer (C) form covalent bonds or ionic bonds may be formed.

[0068] The mixed layer (E) can be formed by heat treatment at a temperature equal to or higher than the softening temperature of the thermoplastic resin layer (B). The heat treatment temperature is preferably within ±60°C of the melting point of the thermoplastic resin, more preferably within ±40°C of the melting point, and even more preferably within ±20°C of the melting point. The heat treatment at a temperature equal to or higher than the softening temperature of the thermoplastic resin (B), which is carried out to form the mixed layer (E), may be performed after the primer layer (C) is formed, after the plating underlayer (d1) described below is formed, or after the plating layer (d2) described below is formed.

[0069] The surface of the primer layer (C) or the mixed layer (E) may be surface-treated, if necessary, by dry treatment such as corona treatment, plasma treatment, or ultraviolet treatment, or wet treatment using ozone water, an aqueous solution of an acid or alkali, or an organic solvent, in order to further improve adhesion to the metal layer (D).

[0070] In the laminate of the present invention, the metal layer (D) may be a plating underlayer (d1) alone, or may be a layer formed of the plating underlayer (d1) and the plating layer (d2), and is formed on the primer layer (C). Examples of metals constituting the plating underlayer (d1) include transition metals or their compounds, with ionic transition metals being preferred. Examples of such ionic transition metals include copper, silver, gold, nickel, palladium, platinum, and cobalt. Among these, silver is preferred from the viewpoints of cost, electroless plating catalytic activity, and conductivity as a plating underlayer.

[0071] The plating underlayer (d1) is selected from any one of a porous metal layer, a continuous metal layer, and a mixed metal layer of a porous and continuous metal layer. The porous metal layer is, for example, a layer formed by applying and drying a fluid of metal particles, and the continuous metal layer is, for example, a layer formed by vapor deposition or sputtering of metal, or by reducing a metal complex film. Among these, a porous metal layer formed from metal particles is preferably used, as it is easy to manufacture at low cost.

[0072] Examples of metals constituting the plating layer (d2) include copper, gold, silver, nickel, chromium, cobalt, and tin. Among these, copper is preferred from the viewpoint of using the laminate of the present invention for the production of printed wiring boards at low cost and with low electrical resistance. The metal constituting the plating layer (d2) does not need to be a single metal, and multiple metal species may be laminated. For example, in the construction of a printed wiring board, a copper plating film may be subjected to plating called final surface treatment of nickel / gold or tin.

[0073] A preferred embodiment of the method for producing the laminate of the present invention is a method in which a primer layer (C) is first laminated on an insulating substrate (A) having a thermoplastic resin layer (B) laminated thereon, and then a fluid containing nano-sized metal particles (d) is applied and organic solvents and the like contained in the fluid are removed by drying to form the plating underlayer (d1), and then the plating layer (d2) is formed by electroplating, electroless plating, or both, and then the metal layer (D) is laminated.

[0074] Furthermore, a preferred embodiment of the method for producing the laminate of the present invention is a method in which a thermoplastic resin layer (B) and a primer layer (C) are sequentially laminated on an insulating substrate (A), and then a fluid containing nano-sized metal particles (d) is applied thereto, and organic solvents and the like contained in the fluid are removed by drying to form the plating underlayer (d1), and then the plating layer (d2) is formed by electroplating, electroless plating, or both, and then the metal layer (D) is laminated thereon.

[0075] The metal particles (d) used to form the plating underlayer (d1) are preferably particulate or fibrous. The metal particles (d) are nanosized. Specifically, when the metal particles (d) are particulate, a fine conductive pattern can be formed, further reducing the resistance. Therefore, the average particle diameter is preferably 1 nm to 200 nm, more preferably 10 nm to 100 nm, and even more preferably 10 nm to 50 nm. The "average particle diameter" is the volume average value measured by diluting the conductive material with a good dispersion solvent and using dynamic light scattering. A Nanotrac UPA-150 (manufactured by Microtrac) can be used for this measurement.

[0076] On the other hand, when the metal particles (d) are fibrous, a fine conductive pattern can be formed and the resistance can be further reduced, so the diameter of the fibers is preferably 5 nm to 100 nm, more preferably 5 nm to 50 nm, and the length of the fibers is preferably 0.1 μm to 100 μm, more preferably 0.1 μm to 30 μm.

[0077] The content of the metal particles (d) in the fluid is preferably 1% by mass or more and 90% by mass or less, more preferably 5% by mass or more and 60% by mass or less, and even more preferably 5% by mass or more and 20% by mass or less.

[0078] The components to be blended into the fluid include dispersants and solvents for dispersing the metal particles (d) in the solvent, and, if necessary, surfactants, leveling agents, viscosity modifiers, film-forming aids, antifoaming agents, preservatives, etc., as described below.

[0079] To disperse the metal particles (d) in a solvent, it is preferable to use a low-molecular-weight or high-molecular-weight dispersant. Examples of the dispersant include dodecanethiol, 1-octanethiol, triphenylphosphine, dodecylamine, polyethylene glycol, polyvinylpyrrolidone, polyethyleneimine, polyvinylpyrrolidone; fatty acids such as myristic acid, octanoic acid, and stearic acid; and polycyclic hydrocarbon compounds having a carboxyl group such as cholic acid, glycyrrhetinic acid, and apicic acid.

[0080] When a plating underlayer (d1) made of metal particles is formed on the primer layer (C), it is preferable to use a compound having a reactive functional group [Y] capable of forming a bond with the reactive functional group [X] possessed by the resin used in the primer resin (c1) described above, since this improves the adhesion between these two layers.

[0081] Examples of compounds having a reactive functional group [Y] include compounds having an amino group, an amide group, an alkylolamide group, a carboxyl group, a carboxyl anhydride group, a carbonyl group, an acetoacetyl group, an epoxy group, an alicyclic epoxy group, an oxetane ring, a vinyl group, an allyl group, a (meth)acryloyl group, a (blocked) isocyanate group, an (alkoxy)silyl group, and the like, and silsesquioxane compounds. In particular, the reactive functional group [Y] is preferably a basic nitrogen atom-containing group, since this can further improve the adhesion between the primer layer (C) and the plating underlayer (d1). Examples of the basic nitrogen atom-containing group include an imino group, a primary amino group, and a secondary amino group.

[0082] The basic nitrogen atom-containing group may be present in one or more molecules of the dispersant. By containing multiple basic nitrogen atoms in the dispersant, some of the basic nitrogen atom-containing groups contribute to the dispersion stability of the metal particles through their interaction with the metal particles, while the remaining basic nitrogen atom-containing groups contribute to improving adhesion to the insulating substrate (A). Furthermore, when a resin having a reactive functional group [X] is used as the primer resin (c1), the basic nitrogen atom-containing group in the dispersant can form a bond with this reactive functional group [X], which is preferable because it further improves adhesion of the metal layer (D) to the insulating substrate (A).

[0083] From the viewpoint of the stability and coatability of the metal particle dispersion, the dispersant is preferably a polymer dispersant, and preferred examples of this polymer dispersant include polyalkyleneimines such as polyethyleneimine and polypropyleneimine, and compounds in which polyoxyalkylene is added to the polyalkyleneimines.

[0084] The compound in which a polyoxyalkylene is added to the polyalkyleneimine may be a compound in which the polyethyleneimine and the polyoxyalkylene are bonded in a linear chain, or a compound in which the polyoxyalkylene is grafted onto a side chain of the main chain made of the polyethyleneimine.

[0085] Specific examples of the compound in which a polyoxyalkylene is added to the polyalkyleneimine include a block copolymer of polyethyleneimine and polyoxyethylene, a compound in which a polyoxyethylene structure is introduced by addition reaction of ethylene oxide with some of the imino groups present in the main chain of polyethyleneimine, and a compound in which an amino group of a polyalkyleneimine, a hydroxyl group of a polyoxyethylene glycol, and an epoxy group of an epoxy resin are reacted with each other.

[0086] Commercially available products of the polyalkyleneimine include "PAO2006W," "PAO306," "PAO318," and "PAO718" from the "Epomin (registered trademark) PAO series" manufactured by Nippon Shokubai Co., Ltd.

[0087] The number average molecular weight of the polyalkyleneimine is preferably in the range of 3,000 to 30,000.

[0088] As the polymer dispersant, urethane resin, acrylic resin, or a compound containing a phosphate group in the urethane resin or acrylic resin can also be suitably used.

[0089] The amount of the dispersant required to disperse the metal particles (d) is preferably 0.01 parts by mass or more and 50 parts by mass or less, and more preferably 0.01 parts by mass or more and 10 parts by mass or less, per 100 parts by mass of the metal particles (c).

[0090] Furthermore, when the dispersant is removed by firing to form a porous plating base layer (d1) for the purpose of further improving the adhesion between the plating base layer (d1) and the plating layer (d2) described later, the content of the dispersant is preferably in the range of 0.1 to 10 parts by mass, more preferably in the range of 0.1 to 5 parts by mass, per 100 parts by mass of the metal particles (d).

[0091] The solvent used for the fluid may be an aqueous medium or an organic solvent. Examples of the aqueous medium include distilled water, ion-exchanged water, pure water, ultrapure water, and mixed solvents of organic solvents miscible with water. Examples of the organic solvent include alcohol compounds, ether compounds, ester compounds, and ketone compounds.

[0092] Examples of the alcohol compound include methanol, ethanol, n-propanol, isopropyl alcohol, n-butanol, isobutyl alcohol, sec-butanol, tert-butanol, heptanol, hexanol, octanol, nonanol, decanol, undecanol, dodecanol, tridecanol, tetradecanol, pentadecanol, stearyl alcohol, allyl alcohol, cyclohexanol, terpineol, terpineol, dihydroterpineol, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monoethyl ether, diethylene glycol monomethyl ether, diethylene glycol monobutyl ether, tetraethylene glycol monobutyl ether, propylene glycol monomethyl ether, dipropylene glycol monomethyl ether, tripropylene glycol monomethyl ether, propylene glycol monopropyl ether, dipropylene glycol monopropyl ether, propylene glycol monobutyl ether, dipropylene glycol monobutyl ether, and tripropylene glycol monobutyl ether.

[0093] In addition to the metal particles (d) and the solvent, the fluid may contain a small amount of ethylene glycol, diethylene glycol, 1,3-butanediol, isoprene glycol, glycerin, etc., if necessary, to improve coating suitability.

[0094] As the surfactant, a common surfactant can be used, and examples thereof include di-2-ethylhexyl sulfosuccinate, dodecylbenzenesulfonate, alkyldiphenyletherdisulfonate, alkylnaphthalenesulfonate, and hexametaphosphate.

[0095] As the leveling agent, a general leveling agent can be used, and examples thereof include silicone-based compounds, acetylene diol-based compounds, and fluorine-based compounds.

[0096] As the viscosity modifier, a general thickener can be used, and examples thereof include acrylic polymers and synthetic rubber latexes that can be thickened by adjusting the pH to alkaline, urethane resins that can be thickened by molecular association, hydroxyethyl cellulose, carboxymethyl cellulose, methyl cellulose, polyvinyl alcohol, hydrated castor oil, amide wax, oxidized polyethylene, metal soaps, and dibenzylidene sorbitol.

[0097] As the film-forming aid, a general film-forming aid can be used, for example, anionic surfactants (such as dioctyl sulfosuccinate sodium salt), hydrophobic nonionic surfactants (such as sorbitan monooleate), polyether-modified siloxane, silicone oil, etc.

[0098] As the defoaming agent, a general defoaming agent can be used, and examples thereof include silicone-based defoaming agents, nonionic surfactants, polyethers, higher alcohols, and polymer-based surfactants.

[0099] As the preservative, a common preservative can be used, and examples thereof include isothiazolinone-based preservatives, triazine-based preservatives, imidazole-based preservatives, pyridine-based preservatives, azole-based preservatives, iodine-based preservatives, and pyrithione-based preservatives.

[0100] The viscosity of the fluid (measured at 25°C using a Brookfield viscometer) is preferably 0.1 mPa·s or more and 500,000 mPa·s or less, and more preferably 0.2 mPa·s or more and 10,000 mPa·s or less. When the fluid is to be coated (printed) by inkjet printing, letterpress reverse printing, or other methods described below, the viscosity is preferably 5 mPa·s or more and 20 mPa·s or less.

[0101] Examples of methods for coating or printing the fluid onto the primer layer (C) include gravure printing, offset printing, flexography, pad printing, gravure offset printing, letterpress printing, letterpress reversal printing, screen printing, microcontact printing, reverse printing, air doctor coater, blade coater, air knife coater, squeeze coater, impregnation coater, transfer roll coater, kiss coater, cast coater, spray coater, inkjet printing, die coater, spin coater, bar coater, and dip coater.

[0102] The mass per unit area of ​​the plating underlayer (d1) is 1 mg / m 2 More than 30,000mg / m 2 Less than 1 mg / m is preferred 2 More than 5,000mg / m 2 The following is preferred:

[0103] The metal layer (D) constituting the laminate of the present invention is a layer provided for the purpose of forming a highly reliable wiring pattern that can maintain good electrical conductivity for a long period of time without causing breakage or the like when the laminate is used in a printed wiring board or the like, for example.

[0104] The plating layer (d2) is a layer formed on the plating base layer (d1), and is preferably formed by a plating process. Examples of this plating process include wet plating methods such as electrolytic plating and electroless plating, which can easily form the plating layer (d2). Two or more of these plating methods may also be combined. For example, the plating layer (d2) may be formed by electroless plating followed by electrolytic plating.

[0105] The electroless plating method is, for example, a method in which an electroless plating solution is brought into contact with the metal constituting the plating underlayer (d1), thereby depositing a metal such as copper contained in the electroless plating solution and forming an electroless plating layer (film) consisting of a metal film.

[0106] The electroless plating solution may contain, for example, a metal such as copper, silver, gold, nickel, chromium, cobalt, or tin, a reducing agent, and a solvent such as an aqueous medium or an organic solvent.

[0107] Examples of the reducing agent include dimethylaminoborane, hypophosphorous acid, sodium hypophosphite, dimethylamineborane, hydrazine, formaldehyde, sodium borohydride, and phenol.

[0108] Furthermore, the electroless plating solution may contain, as necessary, a complexing agent such as an organic acid, such as a monocarboxylic acid such as acetic acid or formic acid; a dicarboxylic acid compound such as malonic acid, succinic acid, adipic acid, maleic acid, or fumaric acid; a hydroxycarboxylic acid compound such as malic acid, lactic acid, glycolic acid, gluconic acid, or citric acid; an amino acid compound such as glycine, alanine, iminodiacetic acid, arginine, aspartic acid, or glutamic acid; or an aminopolycarboxylic acid compound such as iminodiacetic acid, nitrilotriacetic acid, ethylenediaminediacetic acid, ethylenediaminetetraacetic acid, or diethylenetriaminepentaacetic acid, or a soluble salt (sodium salt, potassium salt, ammonium salt, or the like) of these organic acids, or an amine compound such as ethylenediamine, diethylenetriamine, or triethylenetetramine.

[0109] The electroless plating solution is preferably used at a temperature of 20°C or higher and 98°C or lower.

[0110] The electrolytic plating method is a method in which, for example, an electrolytic plating solution is brought into contact with the metal constituting the plating base layer (d1) or the surface of the electroless plating layer (film) formed by the electroless treatment, and electricity is passed through the solution to deposit metals such as copper contained in the electrolytic plating solution on the surface of the metal particles (d) constituting the plating base layer (d1) placed at a cathode or the electroless plating layer (film) formed by the electroless treatment, thereby forming an electrolytic plating layer (metal film).

[0111] Examples of the electrolytic plating solution include plating solutions for metals such as copper, nickel, gold, silver, and chromium.

[0112] The electrolytic plating solution is preferably used at a temperature of 20°C or higher and 98°C or lower.

[0113] The method for forming the plating layer (d2) may be appropriately selected depending on the conductivity of the plating base layer (d1). When the plating base layer (d1) is not conductive, the electroless plating may be performed, followed by electroplating to thicken the layer as needed. When the plating base layer (d1) has sufficient conductivity, it is preferable to directly perform electroplating from the viewpoint of productivity.

[0114] The thickness of the plating layer (d2) is preferably 1 μm or more and 50 μm or less. The thickness of the plating layer (d2) can be adjusted by controlling the treatment time, current density, amount of plating additives used, etc. in the plating treatment step when forming the plating layer (d2).

[0115] The laminate of the present invention, which has a thin metal layer (D) formed thereon, can be used as a substrate for producing printed wiring boards for semi-additive processes. When the laminate of the present invention is used as a laminate for semi-additive processes, the metal layer (D) may be used as a plating base layer (d1) alone, or may be used in the form of a thin plating layer (d2) formed on the plating base layer (d1). When the laminate of the present invention is used as a laminate for semi-additive processes, the thickness of the metal layer D is preferably in the range of 10 nm to 5 μm. From the viewpoint of conductivity as a plating seed, the thickness of the metal layer D is preferably 50 nm or more. From the viewpoint of efficient seed etching after the formation of the conductive layer, the thickness of the metal layer D is more preferably 3 μm or less.

[0116] When the laminate of the present invention is used as a substrate for a subtractive method, the thickness of the metal layer D is not particularly limited and may be appropriately selected depending on the purpose, but from the viewpoints of high-density pattern formation and circuit conductivity, a thickness of 4 μm to 10 μm is preferable. If the required circuit pattern is not fine-pitch, a thicker metal layer D may be formed as necessary.

[0117] The laminate of the present invention can be suitably used as a substrate for producing electronic components such as printed wiring boards, conductive films for touch panels, metal meshes for touch panels, organic solar cells, organic EL elements, organic transistors, RFIDs such as contactless IC cards, electromagnetic wave shields, LED lighting substrates, digital signage, etc. In particular, laminates using low-dielectric materials can be suitably used for producing printed wiring boards with reduced transmission loss in the high-frequency band. [Example]

[0118] The present invention will be described in detail below with reference to examples.

[0119] (Production Example 1: Production of Mixed Resin of Aminotriazine-Modified Novolac Resin and Epoxy Resin) A flask equipped with a thermometer, condenser, distillation column, and stirrer was charged with 750 parts by weight of phenol, 75 parts by weight of melamine, 346 parts by weight of 41.5% by weight formalin, and 1.5 parts by weight of triethylamine, and the mixture was heated to 100°C while taking care to avoid heat buildup. After reacting at 100°C for 2 hours under reflux, the mixture was heated to 180°C over 2 hours while removing water under normal pressure. Unreacted phenol was then removed under reduced pressure to obtain an aminotriazine-modified novolak resin. The hydroxyl group equivalent was 120 g / equivalent. Next, 35 parts by mass of aminotriazine-modified novolac resin and 65 parts by mass of epoxy resin ("EPICLON 850-S" manufactured by DIC Corporation; bisphenol A-type epoxy resin, epoxy group equivalent weight 188 g / equivalent) were mixed, and the mixture was diluted with methyl ethyl ketone to a nonvolatile content of 2% by mass and mixed uniformly to obtain a mixed resin solution of aminotriazine-modified novolac resin and epoxy resin.

[0120] (Preparation Example 1: Preparation of primer composition (1)) Methyl ethyl ketone was added to silica particles (Nissan Chemical Industries, Ltd., "Organosilica sol MIBK-ST-L"; average particle diameter 0.05 μm) to obtain a silica particle dispersion with a nonvolatile content of 2% by mass. Next, 100 parts by mass of the obtained silica particle dispersion was mixed with 100 parts by mass of the mixed resin solution of aminotriazine-modified novolac resin and epoxy resin with a nonvolatile content of 2% by mass obtained in Production Example 1 to obtain a primer composition (1).

[0121] [Preparation of fluid (1)] Cationic silver nanoparticles consisting of gray-green metallic luster flake-like masses, which are a composite of silver nanoparticles and an organic compound having a cationic group (amino group), were obtained according to Example 1 of Japanese Patent No. 4573138. This silver nanoparticle powder was then dispersed in a mixed solvent of 45 parts by mass of ethylene glycol and 55 parts by mass of ion-exchanged water to prepare a fluid (1) containing 5% by mass of cationic silver nanoparticles.

[0122] Example 1 The insulating substrate (A) was an Upilex® polyimide film (manufactured by Ube Industries, Ltd., 50 μm thick), and the thermoplastic resin layer (B) was a tetrafluoroethylene-perfluoroalkane (PFA) copolymer film, Fluon+® EA-2000 film (manufactured by AGC, 25 μm thick, softening point 280°C, melting point 300°C). The EA-2000 film and Upilex were laminated and pressed at 360°C and 10 MPa for 5 minutes to obtain a laminate consisting of the insulating substrate (A) and the thermoplastic resin layer (B). The primer composition (1) obtained in Preparation Example 1 was applied to the surface of the thermoplastic resin layer (B) using a small desktop coater (RK Print Coat Instruments, "K Printing Profer") to a thickness of 400 nm after drying. Next, the laminate was dried at 160°C for 3 minutes using a hot air dryer, thereby obtaining a laminate in which the thermoplastic resin layer (B) and the primer layer (C) were sequentially laminated on the insulating substrate (A).

[0123] The fluid (1) was then applied to the surface of the primer layer (C) of the laminate obtained above using a bar coater, and then dried at 140°C for 1 minute to form a silver layer (thickness 100 nm) corresponding to the plating underlayer (d1) on the surface of the primer layer (C).

[0124] The silver layer obtained above was set on the cathode side, and phosphorus-containing copper was set on the anode side, and an electrolytic plating solution containing copper sulfate was used at a current density of 2.5 A / dm 2 Electrolytic plating was performed for 30 minutes at 200°C, thereby forming a copper electroplated layer (d2) (film thickness: 15 μm) on the surface of the plating base layer (d1). The electrolytic plating solution used was 70 g / L of copper sulfate, 200 g / L of sulfuric acid, 50 mg / L of chloride ions, and 5 ml / L of an additive (Top Lucina SF, manufactured by Okuno Chemical Industries Co., Ltd.). The combination of the plating base layer (d1) and the copper electroplated layer (d2) formed thereon corresponds to the metal layer (D).

[0125] By the above method, a laminate (1) was obtained in which a thermoplastic resin layer (B), a primer layer (C), and a metal layer (D) were laminated in this order on an insulating substrate (A).

[0126] Example 2 A laminate (2) was obtained in the same manner as in Example 1, except that a plating underlayer (d1) was formed by the same method as in Example 1, and then heat treatment was performed at 300°C for 5 minutes. The laminate (2) had a layer in which a mixed layer (E) of a thermoplastic resin layer (B) and a primer layer (C) was formed, and a metal layer (D) were sequentially laminated on an insulating base material (A).

[0127] Example 3 A laminate (3) was obtained in which a layer in which a mixed layer (E) of a thermoplastic resin layer (B) and a primer layer (C) formed thereon, and a metal layer (D) were sequentially laminated on an insulating substrate (A) in the same manner as in Example 1, except that a plating layer (d2) was formed in the same manner as in Example 1 and then heat-treated at 300°C for 5 minutes.

[0128] Example 4 A laminate (4) was obtained in the same manner as in Example 1, except that a primer layer (C) was formed in the same manner as in Example 1 and then heat-treated at 300°C for 5 minutes, and then a layer in which a mixed layer (E) of a thermoplastic resin layer (B) and a primer layer (C) was formed, and a metal layer (D) were sequentially laminated on an insulating substrate (A).

[0129] Example 5 A laminate (5) was obtained in which a layer (E) formed by a mixture of a thermoplastic resin layer (B) and a primer layer (C) and a metal layer (D) were sequentially laminated on an insulating substrate (A) by the same method as in Example 2, except that a continuous metal film was formed by sputtering instead of the silver layer formed in Example 2. The continuous metal film was formed using a sputtering device. A 20 nm thick layer containing 80% nickel and 20% chromium and a 100 nm thick copper layer were sequentially formed on the surface of a laminate in which a thermoplastic resin layer (B) and a primer layer (C) were sequentially laminated on an insulating substrate (A) prepared in the same manner as in Example 2, using an RF sputtering device manufactured by Tokuda Seisakusho, to form a metal layer corresponding to the plating underlayer (d1).

[0130] Example 6 A laminate (6) was obtained in which a layer (E) formed by a mixture of a thermoplastic resin layer (B) and a primer layer (C) and a metal layer (D) was sequentially laminated on an insulating substrate (A) by the same method as in Example 2, except that instead of forming a silver layer as in Example 2, a metal complex layer was reduced to form a continuous metal film. The continuous metal film was formed using silver complex ink TEC-PR-010 (manufactured by InkTec). The silver complex ink was applied using a bar coater and dried at 140°C for 1 minute to form a metal layer (100 nm thick) corresponding to the plating underlayer (d1) on the surface of the primer layer (C).

[0131] Example 7 A laminate (7) was obtained in the same manner as in Example 1, except that a Kaneka PIXEO (registered trademark) film was used instead of the insulating substrate (A) and thermoplastic resin layer (B) used in Example 1. The Kaneka PIXEO film is a polyimide film having a thermoplastic polyimide resin with a glass transition temperature of 275°C on the outermost surface, the insulating substrate (A) is a thermosetting polyimide with a thickness of 34 μm, and the thermoplastic resin layer (B) is a thermoplastic polyimide with a thickness of 8 μm.

[0132] Example 8 A laminate (8) was obtained in the same manner as in Example 7, except that a plating underlayer (d1) was formed by the same method as in Example 7, and then heat treatment was performed at 300°C for 5 minutes. The laminate (8) had a layer in which a mixed layer (E) of a thermoplastic resin layer (B) and a primer layer (C) was formed, and a metal layer (D) were sequentially laminated on an insulating base material (A).

[0133] (Comparative Example 1) The surface of the thermoplastic resin layer of the laminate in which a thermoplastic resin layer (B) was sequentially laminated on the insulating substrate (A) used in Example 1 was aligned with the smooth shine surface of 12 μm rolled copper foil 3EC-M3S-HTE (Mitsui Metals) that had not been subjected to a roughening treatment, and vacuum pressed at a temperature of 360°C and a pressure of 3.7 MPa for 10 minutes to obtain a laminate (R1) in which a thermoplastic resin layer (B) and a metal layer (D) were sequentially laminated on the insulating substrate (A).

[0134] (Comparative Example 2) A laminate (R2) was obtained in which a thermoplastic resin layer (B) and a metal layer (D) were sequentially laminated on an insulating substrate (A) by the same method as in Comparative Example 1, except that a PIXEO (registered trademark) film manufactured by Kaneka was used instead of the insulating substrate (A) and thermoplastic resin layer (B) used in Comparative Example 1.

[0135] The laminates (1) to (8) and (R1) obtained in Examples 1 to 8 and Comparative Example 1 were subjected to the following measurements and evaluations.

[0136] [Peel strength measurement] The peel strength of each laminate obtained above was measured using an Autograph AGS-X 500N manufactured by Shimadzu Corporation. The lead width used for the measurement was 5 mm, and the peel angle was 90°. The peel strength measurement in this invention was performed based on the measured value when the metal plating layer was 15 μm thick.

[0137] [Adhesion evaluation] From the peel strength measured above, the adhesive strength was evaluated according to the following criteria. A: Peel strength is 750N / m or more. B: The peel strength value is 600 N / m or more and less than 750 N / m. C: Peel strength is 450 N / m or more and less than 600 N / m. D: Peel strength value is less than 450 N / m.

[0138] The evaluation results of Examples 1 to 8 and Comparative Examples 1 and 2 are shown in Table 1.

[0139] [Table 1]

[0140] It was confirmed that the laminates (1) to (8) obtained in Examples 1 to 8, which are the laminates of the present invention, have sufficiently high adhesion.

[0141] On the other hand, it was confirmed that the laminates (R1) and (R2) obtained in Comparative Examples 1 and 2 had insufficient adhesion.

Claims

1. A laminate comprising an insulating substrate (A), and a thermoplastic resin layer (B) mainly composed of at least one resin selected from the group consisting of a polyimide resin and a fluorine-containing resin, a mixed layer (E) of the thermoplastic resin layer (B) and a primer layer (C), the primer layer (C), and a metal layer (D) laminated in this order on the insulating substrate (A), the primer layer (C) contains silica particles, an aminotriazine-modified novolak resin, and an epoxy resin; The metal layer (D) is a metal layer in which a plating layer (d2) is laminated on a plating base layer (d1).

2. The laminate according to claim 1, characterized in that the plating underlayer (d1) is selected from at least one of a metal layer of a porous film, a metal layer of a continuous film, or a mixed metal layer of a porous film and a continuous film.

3. 3. The laminate according to claim 2, wherein the porous film is a layer made of metal particles.

4. 4. The laminate according to claim 3, wherein the metal particles constituting the porous film are coated with a polymer dispersant.

5. The laminate according to claim 4, wherein the aminotriazine-modified novolak resin and the epoxy resin contained in the primer layer (C) are resins having a reactive functional group [X], the polymer dispersant according to claim 4 has a reactive functional group [Y], and the reactive functional group [X] and the reactive functional group [Y] can form a bond with each other by reaction.

6. 6. The laminate according to claim 5, wherein the polymer dispersant having the reactive functional group [Y] is at least one selected from the group consisting of polyalkyleneimine and polyalkyleneimine having a polyoxyalkylene structure containing an oxyethylene unit.

7. The laminate according to claim 5, wherein the reactive functional group [X] is at least one selected from the group consisting of a keto group, an acetoacetyl group, an epoxy group, a carboxyl group, an N-alkylol group, an isocyanate group, a vinyl group, a (meth)acryloyl group, and an allyl group.

8. A printed wiring board produced using the laminate according to any one of claims 1 to 7.

9. A step (1) of forming a thermoplastic resin layer (B) on an insulating substrate (A); a step (2) of forming a primer layer (C) on the thermoplastic resin layer (B) and heat-treating the primer layer (C) at a temperature equal to or higher than the softening temperature of the thermoplastic resin layer (B) to form a mixed layer (E) of the thermoplastic resin layer (B) and the primer layer (C); Furthermore, a step (3) of forming a metal layer (D) including a step (3-1) of forming a plating underlayer (d1) on the primer layer (C) and a step (3-2) of forming a plating layer (d2); The method for producing a laminate according to any one of claims 1 to 7, comprising the steps of:

10. a step (2) of forming a primer layer (C) on a substrate having a thermoplastic resin layer (B) on an insulating substrate (A) and then heat-treating the substrate at a temperature equal to or higher than the softening temperature of the thermoplastic resin layer (B) to form a mixed layer (E) of the thermoplastic resin layer (B) and the primer layer (C); Furthermore, a step (3) of forming a metal layer (D) including a step (3-1) of forming a plating underlayer (d1) on the primer layer (C) and a step (3-2) of forming a plating layer (d2); The method for producing a laminate according to any one of claims 1 to 7, comprising the steps of:

11. A step (1) of forming a thermoplastic resin layer (B) on an insulating substrate (A), a step (2) of forming a primer layer (C) on the thermoplastic resin layer (B); Furthermore, after the step (3-1) of forming a plating underlayer (d1) on the primer layer (C), a step (3) of performing heat treatment at a temperature equal to or higher than the softening temperature of the thermoplastic resin layer (B) to form a mixed layer (E) of the thermoplastic resin layer (B) and the primer layer (C); Furthermore, a step (4) of forming a metal layer (D) including a step (3-2) of forming a plating layer (d2); The method for producing a laminate according to any one of claims 1 to 7, comprising the steps of:

12. A step (1) of forming a thermoplastic resin layer (B) on an insulating substrate (A), a step (2) of forming a primer layer (C) on the thermoplastic resin layer (B); Furthermore, a step (3-1) of forming a plating underlayer (d1) on the primer layer (C) and a step (3-2) of forming a plating layer (d2) are included in the step (3) of forming a metal layer (D); a step (4) of performing heat treatment at a temperature equal to or higher than the softening temperature of the thermoplastic resin layer (B) to form a mixed layer (E) of the thermoplastic resin layer (B) and the primer layer (C); The method for producing a laminate according to any one of claims 1 to 7, comprising the steps of:

13. An insulating substrate (A) having a thermoplastic resin layer (B) on the substrate, a step (2) of forming a primer layer (C) on the thermoplastic resin layer (B); Furthermore, after the step (3-1) of forming a plating underlayer (d1) on the primer layer (C), a step (3) of performing heat treatment at a temperature equal to or higher than the softening temperature of the thermoplastic resin layer (B) to form a mixed layer (E) of the thermoplastic resin layer (B) and the primer layer (C); Furthermore, a step (4) of forming a metal layer (D) including a step (3-2) of forming a plating layer (d2); The method for producing a laminate according to any one of claims 1 to 7, comprising the steps of:

14. An insulating substrate (A) having a thermoplastic resin layer (B) on the substrate, a step (2) of forming a primer layer (C) on the thermoplastic resin layer (B); Furthermore, a step (3-1) of forming a plating underlayer (d1) on the primer layer (C) and a step (3-2) of forming a plating layer (d2) are included in the step (3) of forming a metal layer (D); a step (4) of performing heat treatment at a temperature equal to or higher than the softening temperature of the thermoplastic resin layer (B) to form a mixed layer (E) of the thermoplastic resin layer (B) and the primer layer (C); The method for producing a laminate according to any one of claims 1 to 7, comprising the steps of:

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