Laminate

Abstract

To provide a laminate having excellent adhesion between a base material composed of an insulating material and a metal layer formed by sputtering or electroless plating, and further excellent properties in terms of plating solution resistance and thermal resistance.SOLUTION: A laminate has, on a base material composed of an insulating material, a primer layer that includes an acid-modified polyolefin resin and a crosslinking agent, where the acid-modified polyolefin resin contains an ethylene component as a polyolefin component, and the crosslinking agent is at least one compound selected from epoxy compounds, isocyanate compounds, and polyhydrazide compounds.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a laminate. [Background technology]

[0002] Flexible printed circuit boards (FPCs) are one example of wiring boards used in electronic devices. In recent years, as electronic devices have become thinner and lighter, the base films used in these flexible boards are increasingly required to have durability, such as flexibility, and films made of various insulating materials have been proposed (Patent Document 1).

[0003] Flexible printed circuit boards are produced by using a metal-clad laminate such as a copper-clad laminate (CCL), which is made by laminating copper onto an insulating base film, forming copper wiring by, for example, etching the copper, and then laminating a coverlay film to protect the copper wiring. One method for producing a copper-clad laminate is to laminate copper to a resin film with an adhesive layer, followed by thermocompression bonding. The copper foil used here is typically 18 μm or 35 μm thick, but this is not sufficient to accommodate the fine circuit formation that is required due to the increasing density of various devices in recent years.

[0004] Therefore, attempts have been made to produce copper-clad laminates by applying sputtering or electroless plating to a resin film to form a conductor layer made of metal, and then performing additional copper electroplating as necessary (e.g., Patent Documents 2 and 3). However, these methods of laminating a metal layer directly onto a resin film have the problem that the adhesion between the resin film and the metal is insufficient, and the metal is prone to peeling from the resin film during the electroplating process or reflow soldering process. Furthermore, the heat resistance is also insufficient.

[0005] Also, a method has been proposed in which a resin layer containing an acid-modified polyolefin resin is formed on a substrate and then bonded to a metal foil or the like to form a laminate (Patent Documents 4 and 5). Patent Documents 4 and 5 do not evaluate laminates using an insulating film as a substrate. Furthermore, although they describe laminates made of a resin film and a metal foil, or a resin film and a vapor-deposited layer, using an acid-modified polyolefin resin, they do not evaluate the adhesion between the insulating film and the metal foil or the vapor-deposited layer. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Publication No. 2023-180373 [Patent Document 2] Japanese Patent Publication No. 2020-012156 [Patent Document 3] Japanese Patent Application Laid-Open No. 2014-212143 [Patent Document 4] Patent No. 7215091 [Patent Document 5] Patent No. 5427516 Summary of the Invention [Problem to be solved by the invention]

[0007] The present invention has been made to solve the above-mentioned problems, and has an object to provide a laminate that has excellent adhesion between a substrate made of an insulating material and a metal layer formed by sputtering or electroless plating, and that also has excellent plating solution resistance and heat resistance. [Means for solving the problem]

[0008] As a result of extensive research to solve the above problems, the present inventors have found that the above object can be achieved, and have arrived at the present invention. That is, the gist of the present invention is as follows. (1) A laminate having a base material made of an insulating material and a primer layer containing an acid-modified polyolefin resin and a crosslinking agent, wherein the acid-modified polyolefin resin contains an ethylene component as a polyolefin component; A laminate, wherein the crosslinking agent is one or more compounds selected from the group consisting of epoxy compounds, isocyanate compounds, and polyhydric hydrazide compounds. (2) A laminate of (1) in which a copper layer having a thickness of 0.1 μm is formed on the primer layer by sputtering or electroless plating, and when the following peel resistance test is performed, the laminate satisfies the following conditions: [Peeling resistance test] Cross-cut test conforming to JIS K5600-5-6. [conditions] The peeling state of the copper layer is either Class 0, Class 1, or Class 2. (3) The laminate of (1) or (2), wherein the primer layer contains organic and / or inorganic fine particles. (4) A laminate according to any one of (1) to (3), which has a metal layer on the primer layer. [Effects of the Invention]

[0009] The laminate of the present invention has a primer layer of a specific composition on a substrate made of an insulating material, and therefore has excellent adhesion between the substrate and the metal layer when a metal layer is formed on the primer layer by sputtering or electroless plating, and also has excellent plating solution resistance and heat resistance. DETAILED DESCRIPTION OF THE INVENTION

[0010] The present invention will be described in detail below. The laminate of the present invention has a primer layer on a substrate (hereinafter sometimes simply referred to as "substrate") made of an insulating material. The primer layer contains an acid-modified polyolefin resin and, as a crosslinking agent, one or more compounds selected from the group consisting of epoxy compounds, isocyanate compounds, and hydrazide compounds.

[0011] The acid-modified polyolefin resin contains an ethylene component as a polyolefin component. The acid-modified polyolefin resin preferably contains an unsaturated carboxylic acid component as the acid component, which improves the adhesion of the primer layer to the substrate or metal layer and the film-forming properties. The unsaturated carboxylic acid component is introduced from an unsaturated carboxylic acid or its anhydride. Specific examples of the unsaturated carboxylic acid component include acrylic acid, methacrylic acid, maleic acid, maleic anhydride, itaconic acid, itaconic anhydride, fumaric acid, crotonic acid, etc., as well as half esters and half amides of unsaturated dicarboxylic acids. Among these, acrylic acid, methacrylic acid, maleic acid, and maleic anhydride are preferred, with acrylic acid and maleic anhydride being particularly preferred.

[0012] The content of the acid-modified component in the acid-modified polyolefin resin is preferably 0.1 to 10 mass%, more preferably 0.2 to 8 mass%, and even more preferably 0.5 to 6 mass%. If the content of the acid-modified component is less than 0.1 mass%, the acid-modified polyolefin resin will have poor dispersibility in aqueous media and poor solubility in solvents, as will be described later, making it difficult to obtain a composition for forming a primer layer (primer composition), and may also result in insufficient adhesion to the substrate or metal layer.

[0013] The olefin component constituting the acid-modified polyolefin resin of the present invention must contain an ethylene component. By containing an ethylene component, a primer layer having good adhesion to the substrate or metal layer can be obtained, and the heat resistance and plating solution resistance are also excellent. The olefin component may contain an olefin other than an ethylene component, such as an alkene having 2 to 6 carbon atoms, such as propylene, isobutylene, 1-butene, 1-pentene, or 1-hexene. These may be copolymerized with the ethylene component in the same resin, or may be mixed and used as different resins.

[0014] The content of the ethylene component in the acid-modified polyolefin resin is preferably 80% by mass or more, and more preferably 90% by mass or more.

[0015] The acid-modified polyolefin resin may contain a (meth)acrylic acid ester component to improve adhesion to the substrate or metal layer. The content of the (meth)acrylic acid ester component in the acid-modified polyolefin resin is preferably 1 to 25 mass%, more preferably 2 to 22 mass%, even more preferably 3 to 20 mass%, and particularly preferably 5 to 18 mass%. If the content is less than 1 mass%, dispersion in an aqueous medium may be difficult or sufficient crosslinking may not occur, resulting in poor heat resistance. If the content exceeds 25 mass%, resistance to plating solutions may be insufficient.

[0016] Examples of the (meth)acrylic acid ester component include esters of (meth)acrylic acid with alcohols having 1 to 30 carbon atoms. Among these, esters of (meth)acrylic acid with alcohols having 1 to 20 carbon atoms are preferred from the viewpoint of availability. Specific examples of such compounds include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, butyl (meth)acrylate, hexyl (meth)acrylate, octyl (meth)acrylate, decyl (meth)acrylate, lauryl (meth)acrylate, dodecyl (meth)acrylate, and stearyl (meth)acrylate. Mixtures of these compounds may also be used. Among these, from the viewpoint of improving adhesion to the substrate and the metal layer, methyl (meth)acrylate, ethyl (meth)acrylate, butyl (meth)acrylate, hexyl acrylate, and octyl acrylate are more preferred, ethyl acrylate and butyl acrylate are more preferred, and ethyl acrylate is particularly preferred. Note that "(meth)acrylic acid" means "acrylic acid or methacrylic acid."

[0017] The acid-modified polyolefin resin may contain other components in addition to the above components. Examples of other components include alkenes and dienes having more than 6 carbon atoms, such as 1-octene and norbornenes, maleic acid esters, such as dimethyl maleate, diethyl maleate, and dibutyl maleate, (meth)acrylic acid amides, alkyl vinyl ethers, such as methyl vinyl ether and ethyl vinyl ether, vinyl esters, such as vinyl formate, vinyl acetate, vinyl propionate, vinyl pivalate, and vinyl versatate, as well as vinyl alcohols obtained by saponifying vinyl esters with a basic compound, 2-hydroxyethyl acrylate, glycidyl (meth)acrylate, (meth)acrylonitrile, styrene, substituted styrenes, carbon monoxide, and sulfur dioxide, and mixtures of these may also be used.

[0018] The acid-modified polyolefin resin may also contain an N-substituted amide structure in which the hydroxyl group of the carboxyl group is substituted with an N,N-dimethylamino group, an N,N-diethylamino group, or the like.

[0019] The melting point of the acid-modified polyolefin resin is preferably 50 to 150°C, more preferably 60 to 130°C, and even more preferably 70 to 110°C. If the melting point is below the above range, the cohesive strength may be weak, resulting in poor adhesiveness, and there is also a risk of blocking when the resin is laminated on a substrate and wound into a roll. If the melting point exceeds the above range, there is a risk of reduced adhesion to the substrate or metal layer.

[0020] Examples of acid-modified polyolefin resins include ethylene-(meth)acrylic acid copolymers, ethylene-(meth)acrylic acid-maleic anhydride copolymers, acid-modified polyethylene, acid-modified ethylene-propylene resins, acid-modified ethylene-butene resins, acid-modified ethylene-propylene-butene resins, acid-modified styrene-ethylene-butylene-styrene, and ethylene-(meth)acrylic acid ester-unsaturated carboxylic acid copolymers obtained by further acrylic-modifying these acid-modified resins with (meth)acrylic acid esters or the like. Among these, ethylene-(meth)acrylic acid-maleic anhydride copolymers are preferred. Furthermore, the acid-modified polyolefin resins may be chlorinated in an amount of 5 to 40% by mass.

[0021] Examples of acid-modified polyolefin resins that can be used include commercially available products such as the Bondine series and Rotader series manufactured by SK Corporation, the Bestplast series manufactured by Evonik Japan, the Primacol series manufactured by Dow Chemical Company, the Umex series manufactured by Sanyo Chemical Industry Co., Ltd., the Admar series manufactured by Mitsui Chemicals, and the Toyotack series manufactured by Toyobo Co., Ltd. Commercially available solutions or aqueous dispersions can also be used, including the Auroren series and Superclone series manufactured by Nippon Paper Chemicals Co., Ltd., the Zaixen series manufactured by Sumitomo Seika Chemicals Co., Ltd., the Unistall series and Chemipearl series manufactured by Mitsui Chemicals, the Hardlen series manufactured by Toyobo, and the Arrowbase series manufactured by Unitika Co., Ltd. In addition, solvent-dissolved products and solvent-dispersed products dissolved in aqueous solutions or toluene can also be used.

[0022] The primer layer contained in the laminate of the present invention must contain a crosslinking agent, and usable crosslinking agents include one or more selected from epoxy compounds, isocyanate compounds, and polyhydrazide compounds. This allows for the production of a laminate that is superior in adhesion and bonding between the primer layer and the metal layer (plated layer), adhesion and bonding between the substrate and the primer layer, and heat resistance, compared to when other crosslinking agents are used.

[0023] The epoxy compound used in the present invention has an epoxy group, and from the viewpoint of improving adhesiveness and heat resistance, it is preferable that it has two or more epoxy groups in the molecule, and more preferably that it has three or more epoxy groups. Examples of types of epoxy compounds include bisphenol A type epoxy compounds, bisphenol F type epoxy compounds, novolac type epoxy compounds, alicyclic epoxy compounds, dicyclopentadiene type epoxy compounds, biphenyl type epoxy compounds, naphthalene type epoxy compounds, ethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, 1,4-butanediol diglycidyl ether, 1,6-hexanediol diglycidyl ether, trimethylolpropane polyglycidyl ether, pentaerythritol tetraglycidyl ether, sorbitol polyglycidyl ether, glycerol polyglycidyl ether, polyglycerol polyglycidyl ether, etc., but sorbitol polyglycidyl ether and polyglycerol polyglycidyl ether are preferred because they provide high adhesiveness.

[0024] The epoxy equivalent (g / eq.) of the epoxy compound is 600 or less, preferably 400 or less, more preferably 300 or less, and even more preferably 200 or less. If it exceeds 600, adhesion between the substrate and the metal layer (plating) and sufficient heat resistance may not be obtained.

[0025] Examples of isocyanate compounds that can be used include diisocyanates, triisocyanates, and polyfunctional polyisocyanates derived from these. Examples include 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, xylylene diisocyanate, diphenylmethane diisocyanate, isophorone diisocyanate, 1,5-naphthalene diisocyanate, hexamethylene diisocyanate, bis(4-isocyanatocyclohexyl)methane, and hydrogenated diphenylmethane diisocyanate. Further examples include compounds derived from the diisocyanates, such as isocyanurates, adducts, biuret-type compounds, uretdione compounds, and allophanates of the diisocyanates, prepolymers having isocyanate residues (low polymers obtained from diisocyanates and polyols), triglycidyl isocyanurate, and complexes thereof. These may be used alone or in any combination of two or more.

[0026] A polyhydrazide compound is a compound having two or more hydrazide groups in one molecule. Examples of polyhydrazide compounds include oxalyl dihydrazide, succinic dihydrazide, adipic dihydrazide, sebacic dihydrazide, dodecanediohydrazide, isophthalic dihydrazide, salicylic dihydrazide, oxalic dihydrazide, cyclohexanetricarboxylic trihydrazide, butanetricarboxylic trihydrazide, etc. Among these, from the viewpoint of water solubility, it is preferable to use oxalyl dihydrazide, succinic dihydrazide, and adipic dihydrazide, and it is most preferable to use adipic dihydrazide.

[0027] The content of the crosslinking agent can be selected appropriately depending on the desired adhesiveness and heat resistance, but is preferably 0.1 part by mass or more but less than 20 parts by mass, more preferably 0.5 to 15 parts by mass, even more preferably 1.0 to 10 parts by mass, and particularly preferably 1.0 to 5.0 parts by mass, relative to 100 parts by mass of the acid-modified polyolefin resin. If the content of the crosslinking agent is less than 0.1 part by mass, the adhesion between the substrate and metal and heat resistance may be poor, while if it is 30 parts by mass or more, not only will the adhesion between the substrate and metal be poor, but blocking may occur when the substrate is wound into a roll.

[0028] The crosslinking agents used in the present invention are epoxy compounds, isocyanate compounds, and polyhydrazide compounds, but other crosslinking agents may also be blended together. The crosslinking agents that can be blended are not particularly limited, and examples include self-crosslinking agents, compounds having multiple functional groups reactive with carboxyl groups in the molecule, and metals having polyvalent coordination sites. Specifically, melamine compounds, urea compounds, carbodiimide compounds, oxazoline group-containing compounds, zirconium salt compounds, silane coupling agents, allyl compounds, and the like are preferred. Furthermore, multiple of these crosslinking agents may also be used simultaneously.

[0029] (additives) In the laminate of the present invention, the primer layer may contain various additives, such as antioxidants, heat stabilizers, weather stabilizers, UV absorbers, pigments, dyes, organic or inorganic fine particles, fillers, thickeners, leveling agents, antifoaming agents, wetting agents, antistatic agents, nucleating agents, etc., within the range that does not impair the effects of the present invention. It may also contain various additives, resins, and polymers that improve the dielectric properties, such as low-dielectric fillers (boron nitride, fused spherical silica, boron nitride), imide resins, modified LCP resins, fluororesins, CVD polymers, and siloxane polymers. In particular, from the viewpoint of improving the slipperiness of the film, preventing blocking, and preventing scratches due to contact with rolls and the like during processing, the primer layer preferably contains organic and / or inorganic fine particles.

[0030] Examples of resins that can be used to make organic fine particles include polyethylene, polypropylene, polystyrene, silicone resin, nylon, acrylic resin, polyacrylonitrile, benzoguanamine-formaldehyde resin, melamine-formaldehyde resin, styrene-divinylbenzene copolymer, and acrylic-divinylbenzene copolymer.

[0031] Examples of inorganic fine particles include fine particles of silica, colloidal silica, alumina, alumina sol, tin oxide, titanium oxide, zinc oxide, niobium oxide, neodymium oxide, lanthanum oxide, zirconium oxide, cerium oxide, and magnesium oxide.

[0032] Among these, colloidal silica and acrylic particles are preferred from the viewpoint of smoothness, anti-blocking properties and transparency of the film.

[0033] The average particle size of the organic and inorganic fine particles is preferably 0.001 to 10 μm, more preferably 0.01 to 5 μm, and even more preferably 0.05 to 2 μm. If the average particle size is less than 0.001 μm, aggregation of the fine particles may reduce the transparency of the laminate. If the average particle size exceeds 10 μm, not only is it difficult to achieve sufficient lubricity and blocking resistance, but the fine particles may also fall off the primer layer depending on the thickness of the primer layer.

[0034] The content of the organic and / or inorganic fine particles is preferably 0.1 to 10 parts by mass, more preferably 1 to 5 parts by mass, per 100 parts by mass of the acid-modified polyolefin resin constituting the primer layer. If the content is less than 0.1 part by mass, sufficient blocking resistance cannot be obtained, while if it exceeds 10 parts by mass, adhesion to the substrate or metal deteriorates.

[0035] The primer layer may contain a resin other than the acid-modified polyolefin resin, provided that the effects of the present invention are not impaired. Examples of such resins include polyurethane resin, acrylic resin, and polyester resin. Among these, urethane resin is preferred from the viewpoint of improving the heat resistance of the primer layer, its adhesion and bonding to the substrate, and its blocking resistance.

[0036] The thickness of the primer layer is preferably 0.01 to 10 μm, more preferably 0.3 to 8 μm, and even more preferably 0.5 to 5.0 μm. If the primer layer is too thin, not only will sufficient adhesion between the substrate and the metal layer not be obtained, but the fine particles contained in the primer layer may fall off. If the primer layer is too thick, adhesion to the metal layer (plating) may deteriorate, and blocking may occur when the primer layer is wound into a roll.

[0037] Examples of insulating materials that make up the substrate include polyphenylene sulfide resin (including modified), syndiotactic polystyrene resin, liquid crystal resin, polyimide resin, glass, polystyrene resin (including modified), polyester resin, polycarbonate resin, polyphenylene ether resin (including modified), cycloolefin resin (including modified), polyethylene resin, and polypropylene resin.

[0038] Liquid crystal resins are polymers that exhibit a liquid crystalline state (liquid crystallinity) in which the molecular chains are aligned in a nearly regular pattern when the resin is melted at high temperatures or dissolved in a solvent. For example, some resins such as wholly aromatic polyesters, aromatic polyazomethines, aromatic aliphatic polyesters, aromatic polyester carbonates, and wholly aromatic or non-wholly aromatic polyester amides are known to exhibit liquid crystallinity.

[0039] Polyesters known as liquid crystal resins include those obtained by linear polycondensation of parahydroxybenzoic acid and other components, such as polyesters obtained by polycondensation of ethylene terephthalate and parahydroxybenzoic acid, polyesters obtained by polycondensation of phenol, phthalic acid, and parahydroxybenzoic acid, and polyesters obtained by polycondensation of 2,6-hydroxynaphthoic acid and parahydroxybenzoic acid.

[0040] Liquid crystal resins are commercially available. Examples include the Vectra series (A950, E951SX) manufactured by Polyplastics Co., Ltd., the Sumika Super series (E5204L, E6807LHF) manufactured by Sumitomo Chemical Co., Ltd., and the Rodran series (LC5030G, LC5030MF) manufactured by Unitika Ltd. These resins may be mixed with a filler to improve elasticity or strength, or may be ester-amidated to improve the elastic modulus.

[0041] Examples of substrates made of polyimide resin include those in the form of a film, such as a polyimide film obtained by applying a polyamic acid (polyimide precursor) solution obtained by reacting diamines with tetracarboxylic acids to a substrate for preparing a polyimide film, drying the solution to form a precursor film, and then peeling the precursor film from the substrate or subjecting the precursor film to high-temperature heat treatment to cause a dehydration ring-closing reaction.

[0042] The diamine components that make up polyimide resins include p-phenylenediamine (PDA), 4,4'-diaminodiphenyl ether (ODA), 2,2-bis[4-(4-aminophenoxy)phenyl]propane (BAPP), m-phenylenediamine, 2,4-diaminotoluene, 4,4'-diaminobiphenyl, 4,4'-diamino-2,2'-bis(trifluoromethyl)biphenyl (PFMB), 2,2'-dimethyl-4,4'-diaminobiphenyl (DMDB), 3,3'-diaminodiphenylsulfone, 4,4'-diaminodiphenylsulfone, 4,4'-diaminodiphenylsulfide, 4,4'-diaminodiphenylmethane, and 3,4'-diaminodiphenyl ether. ether, 3,3'-diaminodiphenyl ether, 1,4-bis(4-aminophenoxy)benzene, 1,3-bis(4-aminophenoxy)benzene, 1,3-bis(3-aminophenoxy)benzene, 4,4'-bis(4-aminophenoxy)biphenyl, bis[4-(4-aminophenoxy)phenyl]sulfone, bis[4-(3-aminophenoxy)phenyl]sulfone, 2,2-bis[4-(4-aminophenoxy)phenyl]hexafluoropropane, 1,3-bis(aminomethyl)cyclohexane, 1,4-bis(aminomethyl)cyclohexane, bis(aminomethyl)norbornane, 3(4),8(9)-bis(aminomethyl)tricyclo[5.2.1.0 2,6 Examples of diamines include decane, 1,3-cyclohexanediamine, 1,4-cyclohexanediamine, isophoronediamine, 4,4'-methylenebis(cyclohexylamine), 4,4'-methylenebis(2-methylcyclohexylamine), 1,4-diaminobutane, 1,10-diaminodecane, 1,12-diaminododecane, 1,7-diaminoheptane, 1,6-diaminohexane, 1,5-diaminopentane, 1,8-diaminooctane, 1,3-diaminopropane, 1,11-diaminoundecane, 2-methyl-1,5-diaminopentane, and dimer diamine. These may be used alone or in combination of two or more.

[0043] Examples of tetracarboxylic acid components constituting polyimide resins include tetracarboxylic acid dianhydrides such as pyromellitic dianhydride (PMDA), 3,3',4,4'-biphenyltetracarboxylic dianhydride (BPDA), 2,3,3',4'-biphenyltetracarboxylic dianhydride, 3,3',4,4'-benzophenonetetracarboxylic dianhydride (BTDA), 4,4'-oxydiphthalic dianhydride (ODPA), 3,3',4,4'-diphenylsulfonetetracarboxylic dianhydride, 4,4'-(hexafluoroisopropylidene)diphthalic dianhydride (6FDA), and 2,2-bis[4-(3,4-dicarboxyphenoxy)phenyl]propane dianhydride (BPADA). These may be used alone or in combination of two or more.

[0044] Polyphenylene sulfide resin can be produced, for example, by polymerizing an alkali metal sulfide (alkali sulfide) and a dihalobenzene.

[0045] Examples of alkali metal sulfides include lithium sulfide, sodium sulfide, potassium sulfide, rubidium sulfide, and cesium sulfide, with sodium sulfide being preferred. These alkali metal sulfides can be used as hydrates, aqueous mixtures, or anhydrous forms. Alkali metal sulfides prepared in situ in the reaction system, as well as alkali metal sulfides prepared from alkali metal hydrates such as sulfide, lithium hydroxide, and sodium hydroxide and hydrogen sulfide, can also be used. The alkali metal sulfides may be used alone or in combination of two or more.

[0046] Examples of dihalobenzenes include p-dihalobenzenes such as p-dichlorobenzene and p-dibromobenzene, m-dihalobenzenes such as m-dichlorobenzene, and dihalobenzenes containing a substituent other than a halogen atom, such as 1-methoxy-2,5-dihalobenzene and 3,5-dichlorobenzoic acid. Among these, p-dihalobenzenes are preferred, and p-dichlorobenzene is particularly preferred. One type of dihalobenzene may be used alone, or two or more types may be used in combination.

[0047] Syndiotactic polystyrene resin refers to a styrene-based resin having a syndiotactic structure (hereinafter sometimes abbreviated as SPS). "Syndiotactic" means that the phenyl rings of adjacent styrene units are highly likely to be arranged alternately with respect to the plane formed by the main chain of the polymer block. Syndiotactic polystyrene resins, which are arranged alternately in the plane formed by the polymer block main chain, can be quantitatively identified by carbon isotope nuclear magnetic resonance (C-NMR).C-NMR can quantify the proportions of consecutive structural units, such as two consecutive monomer units as a dyad, three consecutive monomer units as a triad, and five consecutive monomer units as a pentad.

[0048] The styrene resin having a syndiotactic structure means polystyrene, poly(hydrocarbon-substituted styrene), poly(halogenated styrene), poly(halogenated alkylstyrene), poly(alkoxystyrene), poly(vinyl benzoate ester), hydrogenated polymers or mixtures thereof, or copolymers containing these as the main component, having a syndiotacticity of usually 75 mol % or more, preferably 85 mol % or more in racemic diad (r), or usually 30 mol % or more, preferably 50 mol % or more in racemic pentad (rrrr).

[0049] Cycloolefin resins are polymeric compounds whose main chains consist of carbon-carbon bonds and at least a portion of which contains a cyclic hydrocarbon structure. This cyclic hydrocarbon structure is introduced by using a compound (cycloolefin) containing at least one olefinic double bond in the cyclic hydrocarbon structure as a monomer, such as norbornene or tetracyclododecene.

[0050] Cycloolefin resins are classified into addition polymers of cycloolefins or hydrogenated products thereof, addition polymers of cycloolefins and α-olefins or hydrogenated products thereof, and ring-opening polymers of cycloolefins or hydrogenated products thereof, and any of these can be used as the cycloolefin resin. Furthermore, the cycloolefin resin may be either a cycloolefin homopolymer or a cycloolefin copolymer.

[0051] Specific examples of cycloolefin resins include cyclopentene, cyclohexene, cyclooctene; monocyclic cycloolefins such as cyclopentadiene and 1,3-cyclohexadiene; bicyclo[2.2.1]hept-2-ene (common name: norbornene), 5-methyl-bicyclo[2.2.1]hept-2-ene, 5,5-dimethyl-bicyclo[2.2.1]hept-2-ene, 5-ethyl-bicyclo[2.2.1]hept-2-ene, and 5-butyl-bicyclo[2.2.1]heptene. bicyclic cycloolefins such as 5-ethylidene-bicyclo[2.2.1]hept-2-ene, 5-hexyl-bicyclo[2.2.1]hept-2-ene, 5-octyl-bicyclo[2.2.1]hept-2-ene, 5-octadecyl-bicyclo[2.2.1]hept-2-ene, 5-methylidene-bicyclo[2.2.1]hept-2-ene, 5-vinyl-bicyclo[2.2.1]hept-2-ene, and 5-propenyl-bicyclo[2.2.1]hept-2-ene;

[0052] Three-ring cycloolefins such as tricyclo[4.3.0.12,5]deca-3,7-diene (trivial name: dicyclopentadiene); tetracycloolefins such as tetracyclo[4.4.0.12,5.17,10]dodec-3-ene (also simply called tetracyclododecene); Examples include polycyclic cycloolefins such as 8-cyclopentyl-tetracyclo[4.4.0.12,5.17,10]dodec-3-ene, tetracyclo[8.4.14,7.01,10.03,8]pentadeca-5,10,12,14-tetraene (also known as 1,4-methano-1,4,4a,5,10,10a-hexahydroanthracene); and tetramers of cyclopentadiene. These cycloolefin resins can be used either alone or in combination as a copolymer.

[0053] As the substrate made of an insulating material, for example, commercially available products can be suitably used. Examples of polyphenylene sulfide resin films include "TORELINA (registered trademark)" manufactured by Toray Industries, Inc. Examples of syndiotactic polystyrene resin films include "XAREK" manufactured by Idemitsu Unitech Co., Ltd. and "Oidys" manufactured by Kurabo Industries, Ltd. Examples of liquid crystal resin films include "Vextar (registered trademark)" manufactured by Kuraray Industries, Inc. Examples of polyimide resin films include "Kapton (registered trademark)" and "Upilex (registered trademark)" manufactured by Toray DuPont Co., Ltd. Examples of cycloolefin resin films include "ZEONOR (registered trademark)" manufactured by Zeon Corporation. Examples of glass substrates include "Low Dielectric Glass Cloth (NE Glass)" manufactured by Nittobo Co., Ltd., "IC Cloth" manufactured by Unitika Ltd., and "Ultra Fine Flat Glass (UFF (registered trademark))" manufactured by Nippon Sheet Glass Co., Ltd.

[0054] Taking into consideration the adhesion to the primer layer and the wettability of the surface, the substrate may be subjected to a pretreatment such as corona treatment, plasma treatment, ozone treatment, chemical treatment, or solvent treatment on the surface.

[0055] The thickness of the substrate is not particularly limited as long as it is within a range that allows the formation of a laminate, and is generally within the range of 1 to 300 μm.

[0056] <Method of manufacturing laminate> The method for producing the laminate of the present invention by providing a primer layer on a substrate is described below. Specifically, either a method (offline method) in which a liquid material (primer composition) for forming a primer layer is applied to the substrate, or a method (inline method) in which a primer composition is applied to the substrate before stretching, followed by stretching and heat treatment, can be used.

[0057] The primer composition is, for example, a composition in which the acid-modified polyolefin resin is dissolved or dispersed in an organic solvent or an aqueous medium, and can be obtained by the following methods, although there are no particular limitations on the method.

[0058] To obtain a primer composition, for example, an acid-modified polyolefin resin is dispersed in an aqueous medium containing water, a basic compound, and a hydrophilic organic solvent. The content of the hydrophilic organic solvent is preferably 1 to 50 mass %, more preferably 3 to 30 mass %, and even more preferably 5 to 25 mass %, of the primer composition to ensure uniform dispersion and to provide adequate wettability to the substrate.

[0059] Examples of hydrophilic organic solvents include alcohols such as methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol, sec-butanol, tert-butanol, n-amyl alcohol, isoamyl alcohol, sec-amyl alcohol, tert-amyl alcohol, 1-ethyl-1-propanol, 2-methyl-1-butanol, n-hexanol, and cyclohexanol; ketones such as methyl ethyl ketone, methyl isobutyl ketone, ethyl butyl ketone, and cyclohexanone; ethers such as tetrahydrofuran and dioxane; ethyl acetate, n-propyl acetate, isopropyl acetate, n-butyl acetate, isobutyl acetate, sec-butyl acetate, and 3-methoxy acetate. Examples of the solvent include esters such as butyl, methyl propionate, ethyl propionate, diethyl carbonate, and dimethyl carbonate; glycol derivatives such as ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monopropyl ether, ethylene glycol monobutyl ether, and ethylene glycol ethyl ether acetate; and further, 1-methoxy-2-propanol, 1-ethoxy-2-propanol, 3-methoxy-3-methyl-1-butanol, methoxybutanol, acetonitrile, dimethylformamide, dimethylacetamide, diacetone alcohol, ethyl acetoacetate, 1,2-dimethylglycerin, 1,3-dimethylglycerin, and trimethylglycerin.

[0060] Examples of basic compounds include ammonia, triethylamine, N,N-dimethylethanolamine, isopropylamine, aminoethanol, dimethylaminoethanol, diethylaminoethanol, ethylamine, diethylamine, isobutylamine, dipropylamine, 3-ethoxypropylamine, 3-diethylaminopropylamine, sec-butylamine, propylamine, n-butylamine, 2-methoxyethylamine, 3-methoxypropylamine, 2,2-dimethoxyethylamine, monoethanolamine, morpholine, N-methylmorpholine, N-ethylmorpholine, pyrrole, and pyridine.

[0061] Furthermore, as a method for dissolving or dispersing the acid-modified polyolefin resin in an organic solvent, it is preferable to use an organic solvent containing an aliphatic hydrocarbon, an alicyclic hydrocarbon, a paraffinic solvent, or an isoparaffinic solvent. Specific examples include aliphatic hydrocarbons such as hexane, heptane, octane, nonane, decane, undecane, and dodecane; alicyclic hydrocarbons such as cyclohexane, cyclohexene, methylcyclohexane, dimethylcyclohexane, and ethylcyclohexane; and isoparaffinic solvents such as isododecane and Shellsol TG. These solvents may be used alone or in combination. The organic solvent may contain the hydrophilic organic solvent described above.

[0062] In addition, as a method for producing the laminate of the present invention, a method can be adopted in which a primer layer is formed on a release film prepared in advance, this layer is bonded to a substrate, and then the release film is peeled off to transfer the primer layer to the substrate.

[0063] The primer composition can be applied to a substrate by any known method, such as gravure roll coating, reverse roll coating, wire bar coating, lip coating, air knife coating, curtain flow coating, spray coating, dip coating, or brush coating. These methods can be used to apply the primer composition uniformly to the surface of the substrate.

[0064] After applying the primer composition to a substrate, the medium can be removed by drying and heat treatment, and a laminate consisting of a dense coating film in which the primer layer is adhered closely to the substrate can be obtained. The laminate of the present invention has a primer layer on at least one side of a substrate, and the primer layer may be provided on both sides of the substrate. Furthermore, a layer other than the primer layer may be provided on the side of the substrate not having the primer layer. The dried thickness and drying conditions of the primer layer are not limited to these, and may be changed depending on the characteristics of the substrate, for example, the dried thickness may be 0.1 to 10 μm, and the drying conditions may be in the range of 50 to 200° C. / 5 to 300 seconds.

[0065] The substrate in the present invention may be a composite having a laminated structure of two or more layers. Examples of the composite include a composite in which no particles are contained in the inner layer but a very small amount of particles are contained in the surface layer, and a composite in which different or the same type of resin is used for the inner and surface layers.

[0066] Furthermore, in consideration of adhesion to the primer layer, the surface of the substrate may be subjected to a pretreatment such as corona treatment, plasma treatment, ozone treatment, chemical treatment, or solvent treatment.

[0067] The laminate of the present invention may have a metal layer on the primer layer of the laminate of the present invention. The metal constituting the metal layer is not particularly limited, and examples thereof include copper, nickel, aluminum, silver, tin, lead, chromium, gold, magnesium, nickel, iron, zinc, zirconium, titanium, silicon, etc. These metals may be used alone or as an alloy of two or more metals. Among these, from the viewpoints of conductivity and cost, it is preferable to use copper or an alloy containing copper.

[0068] The method for laminating a metal layer on the primer layer of the laminate of the present invention is not particularly limited, and examples thereof include a lamination method using a metal foil, a sputtering method, and an electroless plating method. From the viewpoint of ease of controlling the film thickness, the sputtering method or the electroless plating method is preferred.

[0069] When a metal layer is laminated on the primer layer of the laminate of the present invention by sputtering or electroless plating, the metal layer can be made even thicker by electroplating the metal layer. The metal laminated by sputtering or electroless plating and the metal applied by electroplating may be different metals.

[0070] The laminate of the present invention can be used, for example, as a bonding sheet, a resin-coated copper foil, a coverlay film, a printed wiring board, a copper-clad laminate, a flat cable, a circuit board for tape automated bonding, and the like. [Example]

[0071] The present invention will be specifically explained below with reference to examples, but the present invention is not limited to these examples. 1. Evaluation Method (1) Adhesion between the substrate and the primer layer (adhesion to the substrate) The primer composition described below was applied to the substrate described below to a thickness of 3 μm after drying, and then dried at 120° C. for 30 seconds. The adhesion was evaluated by the percentage of the primer layer remaining after peeling with cellophane tape using a cross-cut method according to the method described in JIS K 5600. In practice, a percentage of the primer layer remaining is preferably 85% or more.

[0072] (2) Adhesion strength between substrate and metal layer (adhesion to copper vapor deposition layer) A primer composition was applied to the substrate described below and heated for 15 seconds in a hot air dryer set at 120°C to form a primer layer, resulting in a laminate. The resulting laminate was then placed inside a sputtering deposition apparatus, the pressure inside the apparatus was reduced, argon gas was introduced, and sputtering was performed using copper as the target. The discharge power and sputtering time required for sputtering were appropriately adjusted to form a 0.1 μm-thick copper layer on the primer layer of the laminate. This copper layer was subjected to a cross-cut test in accordance with JIS K5600-5-6, and the state of peeling of the copper layer was visually evaluated using a scale of 0 to 5. In the present invention, it is preferable that the material falls into any one of categories 0, 1 and 2. Category 0: The edges of the cut are completely smooth and there is no peeling on any of the grids. Category 1: Small peeling of the coating at the intersection of the cuts. The affected area of ​​the cross-cuts does not significantly exceed 5%. Category 2: The coating is flaking along the edges of the cuts and / or at the intersections. The cross-cut area is clearly more than 5% affected but not more than 15%. Category 3: The coating has partially or completely peeled off significantly along the edges of the cuts and / or partially or completely peeled off in various areas of the mesh. The cross-cut area is clearly more than 15% affected but not more than 35%. Category 4: The coating is partially or completely torn off in large areas along the edges of the cuts and / or partially or completely torn off in several sections. Not more than 35% of the cross-cut area is affected. Category 5: Any degree of peeling that cannot be classified as Category 4.

[0073] (3) Resistance to plating solution In a 3,000 mL glass graduated cylinder, 150 g of copper(II) sulfate pentahydrate (special reagent grade, manufactured by Nacalai Tesque), 1,200 g of ion-exchanged water, 380 g of sulfuric acid (special reagent grade, manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.), 0.275 g of hydrochloric acid (special reagent grade, concentration 35-37%, manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.), 2 g of Lucent Copper A (manufactured by Meltex Corporation), 2 g of Lucent Copper S (manufactured by Meltex Corporation), and 8 g of Lucent Copper SC (manufactured by Meltex Corporation) were added in this order and stirred with a glass rod until the mixture was homogeneous. Subsequently, ion-exchanged water was poured into the same graduated cylinder and the volume was diluted to 2,000 mL. The mixture was further stirred with a glass rod and used as the plating solution for the experiment. The primer composition was poured into a Teflon (registered trademark) container and heated at 50°C for 48 hours and then at 150°C for 1 minute to obtain a coating film with a thickness of 0.5 mm. This coating film was separated from the Teflon (registered trademark) container and cut into five square test pieces with sides of 2 cm. The total weight of these five test pieces was measured and recorded. Five of the above test pieces were placed in a 100 mL polyethylene bottle, filled with plating solution, and sealed. The bottle was shaken at 60 cycles / min for three days in a shaker equipped with a water bath set at 50°C. All test pieces were then removed from the plating solution, thoroughly rinsed, and heated in a hot air dryer set at 60°C for 15 hours to completely remove the water. The test pieces were then immersed in Sanhayato etching solution (product number H-1000A) for 30 minutes. The test pieces were then removed, rinsed, and dried to completely remove the etching solution. The total weight of the five test pieces was then measured, and the weight change rate due to immersion in the plating solution was calculated using the following formula. From a practical standpoint, a score of △ or higher is preferable. Weight change rate (%) = 100 × (total weight before immersion in plating solution - total weight before immersion in plating solution) / total weight before immersion in plating solution ○: Absolute value of weight change rate is less than 4% △: Absolute value of weight change rate is 4% or more and less than 10% ×: Absolute value of weight change rate is 10% or more

[0074] (4) Adhesion strength between the substrate and the metal layer (adhesion to copper plating) The laminate prepared in (1) was electroplated with copper using the plating solution prepared in (3) to form a copper layer with a thickness of 1 to 5 μm. The laminate was then thoroughly rinsed with water, the water droplets were wiped off, and the laminate was air-dried at room temperature for 3 days. Adhesive tape manufactured by TESA (product number TESA7475) was attached to the edge of the copper layer of the laminate, and the adhesive strength of the substrate was measured in a thermostatic chamber at 23°C using a tensile tester (Shimadzu Corporation, Autograph AGS-100B) at a peel angle of 90° and a peel rate of 50 mm / min. For practical purposes, a peel strength of 6 N / cm or more is preferred, 8 N / cm or more is more preferred, and 10 N / cm or more is particularly preferred.

[0075] (5) Solder heat resistance (heat resistance) A 2.5cm x 2.5cm sample of the laminate with the copper layer prepared in (4) was dried at 120°C for 30 minutes and then immersed in a molten solder bath at 260°C for 1 minute to evaluate the solder heat resistance according to the following criteria. From a practical standpoint, a rating of Fair or better is preferable. 〇: No swelling △: Slight swelling ×: Large swelling

[0076] The following materials and substrates were used for the primer composition. Manufacturing Example 1 Preparation of aqueous dispersion of acid-modified polyolefin resin (E-1) Using a stirrer equipped with a heater-equipped sealable pressure-resistant 1 L glass container, 100 g of acid-modified polyolefin resin [ethylene-ethyl acrylate-maleic anhydride copolymer, ethylene 92% by mass, ethyl acrylate 6% by mass, maleic anhydride 2% by mass, melting point 105 ° C.], 80 g of isopropanol, 4.0 g of N,N-dimethylethanolamine, and 220 g of water were charged into the glass container and heated and stirred at 130 ° C. for 60 minutes. After cooling to room temperature with stirring, 150 g of water was added, and the water and isopropanol were distilled off under reduced pressure using an evaporator to obtain an aqueous dispersion of polyolefin resin particles (E-1).

[0077] Preparation of aqueous dispersion of acid-modified polyolefin resin (E-2) An acid-modified polyolefin resin [ethylene-ethyl acrylate-maleic anhydride copolymer, 80% by mass of ethylene, 18% by mass of ethyl acrylate, 2% by mass of maleic anhydride, melting point 83°C] was used. An aqueous dispersion (E-2) was obtained in the same manner as in the case of E-1.

[0078] Preparation of aqueous dispersion of acid-modified polyolefin resin (E-3) 280 g of a propylene-ethylene copolymer (propylene / ethylene=81.8 / 18.2 (mass ratio), weight average molecular weight 85,000) was heated and melted in a four-neck flask under a nitrogen atmosphere. Then, while maintaining the system temperature at 180°C, 35.0 g of maleic anhydride as an unsaturated carboxylic acid and 6.0 g of di-t-butyl peroxide as a radical generator were added over 2 hours with stirring, followed by a 1-hour reaction. After the reaction was completed, the resulting reaction product was poured into a large amount of acetone to precipitate a resin. This resin was further washed several times with acetone to remove unreacted maleic anhydride, and then dried under reduced pressure in a vacuum dryer to obtain an acid-modified polyolefin resin [mass ratio: propylene 75.4 / ethylene 16.8 / maleic anhydride 7.8, melting point 70°C]. Using the obtained resin, a milky white aqueous polyolefin resin dispersion (E-3) was obtained in the same manner as in the method described in Japanese Patent No. 3759160 (Japanese Patent Application No. 2005-506371).

[0079] Preparation of aqueous dispersion of acid-modified polyolefin resin (E-4) 280 g of a propylene-butene copolymer (propylene / butene=80 / 20 (mass ratio), weight average molecular weight 100,000) was heated and melted in a four-neck flask under a nitrogen atmosphere. Then, while maintaining the system temperature at 170°C, 25.0 g of maleic anhydride as an unsaturated carboxylic acid and 6.0 g of dicumyl peroxide as a radical generator were added over 1 hour, and the mixture was allowed to react for 1 hour. After the reaction was completed, the resulting reaction product was poured into a large amount of acetone to precipitate a resin. This resin was further washed several times with acetone to remove unreacted maleic anhydride, and then dried under reduced pressure in a vacuum dryer to obtain an acid-modified polyolefin resin [mass ratio: propylene 76.4 / ethylene 19.1 / maleic anhydride 4.5, melting point 70°C]. Using the obtained resin, an aqueous dispersion (E-4) was obtained in the same manner as in the case of E-1, except for the above.

[0080] Production of acid-modified polyolefin resin solution (E-5) A nitrogen-purged separable flask was charged with 25 g of styrene-ethylene-butylene-styrene resin (styrene content 15% by mass), 80 g of xylene (Wako Pure Chemical Industries, Ltd.), and 3 g of maleic anhydride (Wako Pure Chemical Industries, Ltd.). The mixture was then heated at 30 rpm for 30 minutes at a system temperature of 130°C to dissolve the resin. Next, 2.4 g of dicumyl peroxide dissolved in 10 g of xylene was added dropwise over 30 minutes with stirring, and the mixture was allowed to react at 130°C for 4 hours. After the reaction was completed, the resulting reaction mixture was poured into a large amount of acetone to precipitate the resin. This resin was further washed several times with acetone to remove unreacted maleic anhydride, and then dried under reduced pressure to obtain a SEBS resin with a maleic anhydride content of 2.6% by mass. The resulting resin was stirred in a solvent of 48% by mass of methylcyclohexane and 20% by mass of methyl ethyl ketone so that the solid content concentration of the resulting resin was 20% by mass, to obtain an acid-modified polyolefin solution (E-5).

[0081] Epoxy compounds C-1: Nagase ChemteX Corporation, Denacol EX-614, sorbitol polyglycidyl ether, multifunctional epoxy resin (having 3 or more epoxy groups), epoxy equivalent 167 C-2: Nagase ChemteX Corporation, Denacol EX-832, polyethylene glycol diglycidyl ether, bifunctional epoxy resin (having two epoxy groups), epoxy equivalent 284 C-3: Nagase ChemteX Corporation, Denacol EX-421, diglycerol polyglycidyl ether, multifunctional epoxy resin, epoxy equivalent 159 C-4: Nagase ChemteX Corporation, Denacol EX-861, polyethylene glycol diglycidyl ether, bifunctional epoxy resin, epoxy equivalent 551

[0082] Isocyanate compounds D-1: Mitsui Chemicals, Inc., Stabio D-370N, 1,5-pentamethylene diisocyanate

[0083] Oxazoline compounds W-1: Nippon Shokubai, Epocross, WS-700

[0084] Polyurethane aqueous dispersion U-1: Polyester polyurethane (Tg: approx. 70°C, Mw: 40300, acid value: 33 mg KOH / g)

[0085] PPS: Polyphenylene sulfide resin film (Toray Industries, Torelina #50-3000, thickness 50 μm) SPS: Syndiotactic polystyrene resin film (Kurabo Oidys, thickness 25 μm) LCP: Liquid crystal resin film (Kuraray Co., Ltd., Vecstar CTF, thickness 50 μm) PI: Polyimide resin film (Kapton, manufactured by Toray DuPont, thickness 50 μm) COP: Cycloolefin resin film (Zeon Corporation, Zeonorfilm ZF16, thickness 55 μm) Glass: Glass cloth (Unitika IC cloth #1017 E01ZSK, thickness 13 μm)

[0086] Example 1 The aqueous dispersion (E-1) of acid-modified polyolefin resin and the epoxy compound (C-1) were mixed so that the solid content mass ratio was 100 / 3, to obtain a primer composition. The obtained primer composition was applied to a substrate so that the thickness after drying would be 1 to 5 μm, and dried under conditions of 120° C.×15 to 30 seconds to form a primer layer, thereby obtaining a laminate. A laminate in which a metal layer was laminated on the primer layer of the laminate was obtained by the methods described in evaluation methods (2), (4) and (5).

[0087] Examples 2 to 28 A laminate was obtained by carrying out the same operations as in Example 1, except that a primer composition was prepared by mixing different types of acid-modified polyolefin resins and different types and contents of crosslinking agents as shown in Table 1, and then applying the primer composition to obtain a primer layer having a thickness as shown in Tables 1 to 2 to obtain a laminate. The evaluation results are summarized in Table 1.

[0088] [Table 1]

[0089] Comparative Examples 1 to 7 A laminate was obtained by the same procedure as in Example 1, except that the types and contents of the acid-modified polyolefin resin and crosslinking agent were changed so as to satisfy the conditions shown in Table 2.

[0090] Comparative Example 8 The substrate used in Example 1 without a primer layer was subjected to various evaluations.

[0091] [Table 2]

[0092] As shown in Examples 1 to 19, the laminate of the present invention was excellent in adhesion to the substrate, adhesion to the metal layer, peel strength of the plated layer, resistance to plating solution, and heat resistance.

[0093] On the other hand, as shown in the comparative examples, when a crosslinking agent outside the scope of the present invention was used, adhesion to the metal layer and heat resistance were poor (Comparative Example 1). Comparative Example 2, which used an acid-modified polyolefin resin outside the scope of the present invention, was inferior in adhesion to the metal layer, peel strength of the plating layer, heat resistance, and plating solution resistance. Comparative Example 7, which did not contain an acid-modified polyolefin resin, was inferior in adhesion to the metal layer, peel strength of the plating layer, and heat resistance. Furthermore, when the primer layer did not contain a crosslinking agent (Comparative Examples 3, 4, 5, and 6), the adhesion to the substrate, adhesion to the metal layer, heat resistance, and peel strength after plating lamination were poor. Furthermore, when no primer layer was provided, the adhesion between the substrate and the metal layer, the peel strength of the plating layer, and the heat resistance were poor (Comparative Example 8).

Claims

1. A laminate having a base material made of an insulating material and a primer layer containing an acid-modified polyolefin resin and a crosslinking agent, the acid-modified polyolefin resin contains an ethylene component as a polyolefin component, A laminate, wherein the crosslinking agent is at least one selected from the group consisting of an epoxy compound, an isocyanate compound, and a polyhydric hydrazide compound.

2. 2. The laminate according to claim 1, wherein a copper layer having a thickness of 0.1 μm is formed on the primer layer by sputtering or electroless plating, and when subjected to the following peel resistance test, the laminate satisfies the following conditions: [Peel resistance test] Cross-cut test conforming to JIS K5600-5-6. [conditions] The peeling state of the copper layer is either Class 0, Class 1 or Class 2.

3. The laminate according to claim 1 or 2, wherein the primer layer contains organic and / or inorganic fine particles.

4. The laminate according to claim 1 or 2, which has a metal layer on the primer layer.

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