Classifications

• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L79/00—Compositions of macromolecular compounds obtained by reactions forming in the main chain of the macromolecule a linkage containing nitrogen with or without oxygen or carbon only, not provided for in groups C08L61/00 - C08L77/00
  • C08L79/04—Polycondensates having nitrogen-containing heterocyclic rings in the main chain; Polyhydrazides; Polyamide acids or similar polyimide precursors
  • C08L79/08—Polyimides; Polyester-imides; Polyamide-imides; Polyamide acids or similar polyimide precursors
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B32—LAYERED PRODUCTS
  • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
  • B32B27/00—Layered products comprising a layer of synthetic resin
  • B32B27/28—Layered products comprising a layer of synthetic resin comprising synthetic resins not wholly covered by any one of the sub-groups B32B27/30 - B32B27/42
  • B32B27/281—Layered products comprising a layer of synthetic resin comprising synthetic resins not wholly covered by any one of the sub-groups B32B27/30 - B32B27/42 comprising polyimides
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B32—LAYERED PRODUCTS
  • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
  • B32B27/00—Layered products comprising a layer of synthetic resin
  • B32B27/34—Layered products comprising a layer of synthetic resin comprising polyamides
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
  • C08K3/00—Use of inorganic substances as compounding ingredients
  • C08K3/01—Use of inorganic substances as compounding ingredients characterized by their specific function
  • C08K3/013—Fillers, pigments or reinforcing additives
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L51/00—Compositions of graft polymers in which the grafted component is obtained by reactions only involving carbon-to-carbon unsaturated bonds; Compositions of derivatives of such polymers
  • C08L51/04—Compositions of graft polymers in which the grafted component is obtained by reactions only involving carbon-to-carbon unsaturated bonds; Compositions of derivatives of such polymers grafted on to rubbers
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L63/00—Compositions of epoxy resins; Compositions of derivatives of epoxy resins
• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
  • C09J11/00—Features of adhesives not provided for in group C09J9/00, e.g. additives
  • C09J11/02—Non-macromolecular additives
  • C09J11/04—Non-macromolecular additives inorganic
• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
  • C09J11/00—Features of adhesives not provided for in group C09J9/00, e.g. additives
  • C09J11/08—Macromolecular additives
• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
  • C09J163/00—Adhesives based on epoxy resins; Adhesives based on derivatives of epoxy resins
• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
  • C09J179/00—Adhesives based on macromolecular compounds obtained by reactions forming in the main chain of the macromolecule a linkage containing nitrogen, with or without oxygen, or carbon only, not provided for in groups C09J161/00 - C09J177/00
  • C09J179/04—Polycondensates having nitrogen-containing heterocyclic rings in the main chain; Polyhydrazides; Polyamide acids or similar polyimide precursors
  • C09J179/08—Polyimides; Polyester-imides; Polyamide-imides; Polyamide acids or similar polyimide precursors
• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
  • C09J7/00—Adhesives in the form of films or foils
  • C09J7/20—Adhesives in the form of films or foils characterised by their carriers
  • C09J7/22—Plastics; Metallised plastics
  • C09J7/25—Plastics; Metallised plastics based on macromolecular compounds obtained otherwise than by reactions involving only carbon-to-carbon unsaturated bonds
• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
  • C09J7/00—Adhesives in the form of films or foils
  • C09J7/30—Adhesives in the form of films or foils characterised by the adhesive composition
  • C09J7/35—Heat-activated
• • H—ELECTRICITY
  • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
  • H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
  • H05K3/00—Apparatus or processes for manufacturing printed circuits
  • H05K3/22—Secondary treatment of printed circuits
  • H05K3/28—Applying non-metallic protective coatings
  • H05K3/281—Applying non-metallic protective coatings by means of a preformed insulating foil

Definitions

• the present invention relates to a thermosetting resin composition, a coverlay film, and a flexible printed wiring board.
• Patent Document 1 discloses a flexible printed wiring board that includes a coverlay film with an adhesive layer, and a substrate on which wiring is formed and a coverlay film that covers the wiring, and is designed to be placed in a high-temperature environment for a long period of time. It also discloses an adhesive resin composition that can be used for the adhesive layer that constitutes the coverlay film. Specifically, it discloses an adhesive resin composition that includes a siloxane-containing polyimide resin and a bisphenol-type vinyl ester resin.
• the bisphenol vinyl ester resin contained in this adhesive resin composition is easily degraded and oxidized by heat. For this reason, if a coverlay film using this adhesive resin composition as an adhesive layer is placed in a high-temperature environment for a long period of time, the adhesive layer will deteriorate and the adhesive strength between the adhesive layer and the adherend will easily decrease.
• the present invention has been made in consideration of the above circumstances, and aims to provide a coverlay film that has excellent adhesion even when placed in a high-temperature environment for a long period of time, a flexible printed wiring board that includes this coverlay film, and a thermosetting resin composition that can be used in the adhesive layer of this coverlay film.
• the present invention is as follows. [1] A polyamide-imide resin having an acrylonitrile-butadiene rubber skeleton; an epoxy resin that is non-solid at 25°C; fine particle rubber dispersed in the non-solid epoxy resin; An inorganic filler; A curing agent, The content of the non-solid epoxy resin is 30 parts by mass or more and 70 parts by mass or less relative to 100 parts by mass of the polyamide-imide resin, The content of the fine particle rubber is 5 parts by mass or more and 20 parts by mass or less with respect to 100 parts by mass of the polyamide-imide resin, The thermosetting resin composition, wherein the inorganic filler is contained in an amount of 20 parts by mass or more and 40 parts by mass or less relative to 100 parts by mass of the polyamideimide resin.
• thermosetting resin composition described in [1] above in which the microparticle rubber is composed of a core layer and a shell layer covering the surface of the core layer.
• the present invention provides a coverlay film that has excellent adhesion even when placed in a high-temperature environment for a long period of time, a flexible printed wiring board that includes this coverlay film, and a thermosetting resin composition that can be used in the adhesive layer of this coverlay film.
• the embodiment is an example for explaining the present invention, and is not intended to limit the present invention to the following content.
• the present invention can be carried out with appropriate modifications within the scope of its gist.
• the parts by mass used in the present invention means the parts by mass of the resin excluding volatile components such as organic solvents contained in the resin, that is, the parts by mass of the non-volatile components.
• the semi-cured state (B stage) means a state in which the curing reaction of the thermosetting resin composition has progressed halfway.
• thermosetting resin composition includes a polyamide-imide resin having an acrylonitrile-butadiene rubber skeleton, an epoxy resin that is non-solid at 25° C., fine particle rubber dispersed in the non-solid epoxy resin, an inorganic filler, and a curing agent.
• thermosetting resin composition of the embodiment has excellent heat resistance and adhesiveness due to the inclusion of the above-mentioned components.
• This thermosetting resin composition is suitable as a resin composition that constitutes the adhesive layer of a coverlay film.
• thermosetting resin composition The components contained in the thermosetting resin composition are explained below.
• the polyamide-imide resin used in the embodiment is composed of (a) component: a polycarboxylic acid derivative having an acid anhydride group, (b) component: an isocyanate compound, and (c) component: an acrylonitrile butadiene rubber having carboxyl groups at both ends.
• a component a polycarboxylic acid derivative having an acid anhydride group
• component an isocyanate compound
• component an acrylonitrile butadiene rubber having carboxyl groups at both ends.
• NBR acrylonitrile butadiene rubber
• polycarboxylic acid derivatives having an acid anhydride group examples include trimellitic anhydride, pyromellitic dianhydride, ethylene glycol bisanhydrotrimellitate, 3,3',4,4'-benzophenonetetracarboxylic dianhydride, 3,3',4,4'-biphenyltetracarboxylic dianhydride, etc. These may be used alone or in combination of two or more.
• Component (b) examples of the isocyanate compound include diphenylmethane-4,4'-diisocyanate, tolylene-2,4-diisocyanate, m-xylylene diisocyanate, 2,2'-dimethylbiphenyl-4,4'-diisocyanate, 3,3'-dimethylbiphenyl-4,4'-diisocyanate, tolylene-2,4'-diisocyanate, etc. These may be used alone or in combination of two or more kinds.
• the acrylonitrile butadiene rubber having carboxyl groups at both ends imparts adhesiveness and flexibility to the thermosetting resin composition.
• the weight average molecular weight of the NBR having carboxyl groups at both ends is preferably 1000 or more and 4000 or less from the viewpoint of imparting adhesiveness and flexibility to the thermosetting resin composition.
• the polyamide-imide resin used in the embodiment is obtained by the isocyanate method.
• the components (a), (b), and (c) are added to a vessel so as to satisfy the following formula, and are condensed by heating to, for example, 100° C. or higher and 180° C. or lower.
• An organic solvent such as N,N-dimethylacetamide, N-methyl-2-pyrrolidone, or ⁇ -butyrolactone may be added during the condensation.
• number of isocyanate groups contained in component (b)/ ⁇ number of acid anhydride groups contained in component (a)+number of carboxyl groups contained in component (c) ⁇ 0.8 or more and 1.2 or less
• the polyamide-imide resin obtained by the above-mentioned method improves the film-forming properties of the thermosetting resin composition of the embodiment.
• the glass transition temperature of the obtained polyamideimide resin is 150°C or higher and 200°C or lower.
• This polyamideimide resin improves the heat resistance of the thermosetting resin composition of the embodiment.
• the glass transition temperature can be determined by measuring the dynamic viscoelasticity of the polyamideimide resin.
• Non-solid epoxy resin at 25°C The epoxy resin that is non-solid at 25° C. has fluidity at 25° C.
• the epoxy resin has two or more epoxy groups in one molecule.
• the epoxy equivalent of the epoxy resin is preferably 100 g/eq or more and 400 g/eq or less, more preferably 150 g/eq or more and 350 g/eq or less.
• the epoxy resin can increase the dispersibility of the fine particle rubber in the thermosetting resin composition, and can increase the adhesion between the substrate and the adhesive layer that constitutes the coverlay film.
• Epoxy resins that are non-solid at 25°C include, for example, bisphenol A type epoxy resins, bisphenol F type epoxy resins, bisphenol A novolac type epoxy resins, phenol novolac type epoxy resins, amine type epoxy resins, and alicyclic epoxy resins. From the viewpoint of heat resistance, bisphenol A type epoxy resins are preferred as non-solid epoxy resins at 25°C, and bisphenol A novolac type epoxy resins and phenol novolac type epoxy resins are more preferred. Two or more types of epoxy resins that are non-solid at 25°C may be used in combination.
• the content of non-solid epoxy resin at 25°C is 30 parts by mass or more and 70 parts by mass or less per 100 parts by mass of polyamideimide resin, from the viewpoint of improving the adhesion between the substrate and the adhesive layer that constitutes the coverlay film.
• the fine particle rubber may be any fine particle rubber that disperses in a non-solid epoxy resin at 25° C., and from the viewpoint of improving dispersibility, a fine particle rubber composed of a core layer and a shell layer covering the surface of the core layer is preferred.
• the core layer constituting the microparticle rubber is composed of a polymer having rubber-like elasticity.
• polymers having rubber-like elasticity include diene rubber, acrylic rubber, styrene rubber, and polysiloxane rubber.
• the core layer may be composed of two or more types of polymers.
• the shell layer covering the surface of the core layer is composed of a copolymer obtained by copolymerizing one or more components selected from (meth)acrylic acid ester monomers, aromatic vinyl monomers, vinyl cyanide monomers, unsaturated acid derivatives, (meth)acrylamide derivatives, and maleimide derivatives.
• the polymer constituting the core layer and the copolymer constituting the shell layer are bonded by graft polymerization.
• the shell layer covers a part or the whole of the surface of the core layer.
• the copolymer constituting the shell layer preferably has a functional group that reacts with a non-solid epoxy resin and a hardener at 25°C.
• the fine particle rubber having such a structure has an increased affinity with a non-solid epoxy resin at 25°C, improving dispersibility.
• Examples of functional groups that react with a non-solid epoxy resin and a hardener at 25°C include a hydroxyl group, a carboxyl group, and an epoxy group, and from the viewpoint of improving dispersibility, an epoxy group is preferable.
• the size of the fine rubber particles is preferably such that the average particle size is 0.05 ⁇ m or more and 1 ⁇ m or less in order to improve dispersibility.
• the content of the fine particle rubber is 5 parts by mass or more and 20 parts by mass or less per 100 parts by mass of polyamideimide resin, from the viewpoint of improving the adhesion between the substrate and the adhesive layer that constitutes the coverlay film.
• an epoxy resin that is non-solid at 25°C in which the fine particle rubber is dispersed is added to the thermosetting resin composition.
• examples of epoxy resins that are non-solid at 25°C in which the fine particle rubber is already dispersed include MX-136, MX-153, MX-154, MX-170, MX-217, MX-257, MX-416, MX-451, MX-551, MX-960, MX-965, etc., manufactured by Kaneka Corporation. Two or more types of epoxy resins that are non-solid at 25°C in which the fine particle rubber is already dispersed may be used in combination.
• the curing agent may be any agent capable of curing a non-solid epoxy resin at 25° C., and examples thereof include diaminodiphenylmethane (DDM), diaminodiphenylsulfone (DDS), diaminodiphenylether (DDE), hexamethylenediamine, dicyandiamide, and phenol novolac.
• DDM diaminodiphenylmethane
• DDS diaminodiphenylsulfone
• DDE diaminodiphenylether
• dicyandiamide is preferred from the viewpoint of ease of controlling the curing reaction
• diaminodiphenylsulfone is more preferred.
• Two or more types of curing agents may be used in combination.
• the equivalent weight of the curing agent is preferably 0.3 to 0.8 equivalents, more preferably 0.3 to 0.6 equivalents, relative to 1 equivalent of the epoxy group of the non-solid epoxy resin at 25°C.
• inorganic filler examples include aluminum hydroxide, magnesium hydroxide, and silica. From the viewpoint of improving heat resistance and exhibiting flame retardancy, the inorganic filler is preferably aluminum hydroxide, and more preferably magnesium hydroxide. Two or more kinds of inorganic fillers may be used.
• the content of the inorganic filler is 20 parts by mass or more and 40 parts by mass or less per 100 parts by mass of polyamideimide resin, from the viewpoint of increasing the adhesion between the substrate and the adhesive layer that constitutes the coverlay film.
• thermosetting resin composition can be obtained by adding the above-mentioned components, i.e., polyamide-imide resin, epoxy resin that is non-solid at 25°C, fine particle rubber dispersed in the non-solid epoxy resin, inorganic filler, and curing agent, in a container in predetermined amounts and mixing them.
• a thermosetting resin composition has excellent heat resistance and adhesive properties.
• the thermosetting resin composition may further contain other additives.
• the other additives include imidazole accelerators such as 2-methylimidazole, N-benzyl-2-methylimidazole, and 2-undecylimidazole, Lewis acid complexes such as boron trifluoride monoethylamine, polyamines, and hardening accelerators such as melamine resins, dispersants, softeners, antioxidants, pigments, dyes, and silane coupling agents. Two or more types of additives may also be used.
• the coverlay film of the embodiment is composed of, for example, a polyimide film and an adhesive layer laminated on one side thereof.
• the coverlay film of the embodiment is used to protect wiring formed on a substrate. From the viewpoint of reducing deterioration due to oxygen when the adhesive layer is placed in a high-temperature environment for a long period of time, it is preferable that the oxygen permeability of the polyimide film is low.
• the oxygen permeability of the polyimide film at 30° C. is preferably 35.0 ⁇ 10 ⁇ 6 m 3 /m 2 ⁇ atm ⁇ 24hr or less.
• the coverlay film has excellent adhesion even when placed in a high-temperature environment for a long period of time.
• the thickness of the polyimide film is sufficient to function as a coverlay film, and from the viewpoint of processability, it is, for example, 2 ⁇ m or more and 75 ⁇ m or less. Furthermore, from the viewpoint of reducing oxygen permeability, it is preferable that the thickness of the polyimide film is 12.5 ⁇ m or more.
• the thickness of the adhesive layer may be any thickness that is sufficient to protect the wiring formed on the substrate, and may be, for example, 5 ⁇ m to 50 ⁇ m after drying.
• the cured state of the adhesive layer before lamination onto the substrate i.e., the cured state of the thermosetting resin composition, is in a semi-cured state (B stage).
• the adhesive layer may be formed on both sides of the polyimide film. With a coverlay film having this configuration, adhesive layers are formed on both sides of the polyimide film, so that the wiring surface of one substrate and the wiring surface of another substrate can be protected by a single coverlay film, making it possible to form multi-layered substrates.
• thermosetting resin composition of the embodiment is prepared.
• the thermosetting resin composition is applied to one side of a polyimide film using a coating device.
• the film to which the thermosetting resin composition has been applied is heated until the thermosetting resin composition reaches a semi-cured state (B stage), and then cooled.
• a coverlay film is obtained in which an adhesive layer is laminated on one side of a polyimide film.
• the heating conditions are, for example, 100°C or higher and 250°C or lower, and 5 seconds or longer and 30 minutes or shorter, and can be adjusted depending on the thickness of the adhesive layer.
• An organic solvent may be added to the thermosetting resin composition to improve coating properties.
• the organic solvent to be added to the thermosetting resin composition may be any solvent capable of adjusting the viscosity of the thermosetting resin composition, and examples of such organic solvents include glycols such as ethylene glycol and propylene glycol; glycol monoalkyl ethers such as ethylene glycol monomethyl ether and ethylene glycol monoethyl ether; glycol dialkyl ethers such as ethylene glycol dimethyl ether and ethylene glycol diethyl ether; alkyl esters such as methyl acetate, ethyl acetate, propyl acetate, and methyl acetoacetate; ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone; aromatic hydrocarbons such as benzene, toluene, xylene, and ethylbenzene; aliphatic hydrocarbons such as hexane, cyclohexane, and oc
• the coating device may be any device capable of layering the thermosetting resin composition onto a film at a predetermined thickness.
• coating devices include die coaters, comma coaters, and gravure coaters.
• the flexible printed wiring board of the embodiment includes a substrate on which wiring is formed and a coverlay film having an adhesive layer, and the coverlay film is laminated on the substrate so that the wiring and the adhesive layer are in contact with each other.
• Examples of wiring formed on a substrate include wiring formed by etching the copper layer of a copper-plated laminate or a copper-clad laminate, and wiring printed with conductive ink.
• Materials constituting the wiring are conductive materials, such as copper, silver, and zinc.
• the thickness of the substrate constituting the flexible printed wiring board is, for example, 15 ⁇ m or more and 200 ⁇ m or less, from the viewpoint of making the flexible printed wiring board flexible.
• the copper-plated laminate has a copper layer composed of copper plating.
• the copper-clad laminate has a copper layer composed of copper foil.
• a method for manufacturing a flexible printed wiring board is described below. First, a substrate on which wiring is formed and a coverlay film with an adhesive layer are prepared. Next, the coverlay film is laminated so that the adhesive layer is in contact with the surface of the substrate on which wiring is formed, and then heated and pressurized. In this way, a flexible printed wiring board is obtained.
• the conditions for heating and pressing are, for example, 120°C to 250°C, 5 seconds to 120 minutes, and 1 MPa to 10 MPa, and can be adjusted depending on the laminate configuration.
• a coverlay film that includes a polyimide film and an adhesive layer made of a thermosetting resin composition, with the adhesive layer being laminated on at least one side of the polyimide film, but the following modified examples are also included as embodiments.
• the modified example further includes a gas barrier layer that suppresses oxygen transmission.
• the gas barrier layer is laminated on at least one surface of the polyimide film that constitutes the coverlay film.
• the polyimide film on which the gas barrier layer is laminated has an oxygen transmission rate at 30° C. of, for example, 5.0 ⁇ 10 ⁇ 6 m 3 /m 2 ⁇ atm ⁇ 24 hr or less.
• the adhesive layer may be laminated on the side of the polyimide film opposite to the side on which the gas barrier layer is laminated, or may be laminated on top of the gas barrier layer.
• the gas barrier layer may be any layer capable of suppressing oxygen permeation, and examples of the gas barrier layer include a gas barrier layer made of silicon dioxide (SiO 2 ), zinc oxide, etc.
• the thickness of the gas barrier layer is, for example, 10 nm or more and 100 nm or less.
• a polyimide film having a gas barrier layer laminated thereon reduces oxygen permeation. This reduces the contact between oxygen and the adhesive layer laminated on the film, reducing deterioration of the adhesive layer due to oxygen, i.e., deterioration of the thermosetting resin composition due to oxygen, and suppresses a decrease in the adhesive strength between the adhesive layer and the wiring.
• Polyamide-imide resin has an acrylonitrile butadiene rubber skeleton and has a glass transition temperature of 178° C. (HR-71DD, manufactured by Toyobo Co., Ltd.). The glass transition temperature was measured using RSA-G2 manufactured by TA-instruments Co., Ltd. The conditions were tensile mode, in air, 1 Hz, and temperature rise of 10° C./min.
• Epoxy resin EA having an epoxy equivalent of 231 g/eq, being a phenol novolac type, containing 25 parts by mass of fine particle rubber (polybutadiene rubber, average particle size 0.1 ⁇ m) per 100 parts by mass of epoxy resin EA (manufactured by Kaneka Corporation, MX-217);
• Epoxy resin EB having an epoxy equivalent of 270 g/eq, being a bisphenol A type, containing 33 parts by mass of fine particle rubber (polybutadiene rubber, average particle size 0.1 ⁇ m) per 100 parts by mass of epoxy resin EB (manufactured by Kaneka Corporation, MX-153);
• Epoxy resin EC having an epoxy equivalent of 270 g/eq, being a bisphenol A novolac type, containing 25 parts by mass of fine particle rubber (styrene butadiene rubber, average particle size 0.1 ⁇ m) per 100 parts by mass of epoxy resin EC (manufactured by Kaneka Corporation, MX-153
• Diaminodiphenylsulfone having an amine value of 62 g/eq (Konishi Chemical Industry Co., Ltd., 3,3'-DAS).
• Filler FA Magnesium hydroxide (Kyowa Chemical Industry Co., Ltd., KISUMA (registered trademark) 5P), (2) Filler FB: Aluminum hydroxide (manufactured by Nippon Light Metal Co., Ltd., BF013), (3) Filler FC: Silica (manufactured by Admatechs Co., Ltd., SC2010-MB).
• Example 1 (Preparation of Thermosetting Resin Composition) A container was charged with 100 parts by mass of polyamideimide resin, 52 parts by mass of epoxy resin EA, 8.4 parts by mass of curing agent, 30 parts by mass of filler FA, 100 parts by mass of methyl ethyl ketone as an organic solvent, and 260 parts by mass of toluene, and the mixture was stirred at room temperature to obtain a thermosetting resin composition.
• thermosetting resin composition was applied to one side of a 25 ⁇ m thick polyimide film (Kapton (registered trademark) 100EN, manufactured by Toray DuPont Co., Ltd.) with a bar coater so that the thickness after heating would be 30 ⁇ m, and the film was heated at 150° C. for 5 minutes. Thereafter, a release PET film (Lumirror (registered trademark) #38-S10, manufactured by Toray Co., Ltd.) was attached to the film surface on which the thermosetting resin composition was applied under conditions of 100° C., 1 MPa, and 10 seconds to obtain a coverlay film with a release PET film.
• the oxygen permeability at 30° C. of the polyimide film used in Example 1 was 31.0 ⁇ 10 ⁇ 6 m 3 /m 2 ⁇ atm ⁇ 24hr.
• the oxygen permeability at 30° C. was measured in accordance with ASTM D1434.
• coverlay film peel strength refers to pulling the coverlay in a 90° direction (perpendicular direction) to the surface of the measurement sample.
• adherend pull refers to pulling the adherend in a 90° direction (perpendicular direction) to the surface of the measurement sample. The same applies below.
• the evaluation criteria were as follows: Excellent: peel strength is 7.0 N/cm or more; Good: Peel strength is 3.4 N/cm or more and less than 7.0 N/cm; Poor: Peel strength is less than 3.4 N/cm.
• thermosetting resin compositions were prepared in the same manner as in Example 1, except that the type and content of each component was changed.
• the unit of content in the tables is parts by mass unless otherwise specified.
• Example 11 differs from Example 1 only in the polyimide film described below, and the other configurations are the same as those of Example 1.
• Example 2 the same 25 ⁇ m thick polyimide film (Kapton (registered trademark) 100EN, manufactured by DuPont Toray Co., Ltd.) as in Example 1 was used.
• Example 11 a film was used in which a 30 nm thick gas barrier layer made of SiO 2 was laminated on one side of a 25 ⁇ m thick polyimide film (Kapton (registered trademark) 100EN, manufactured by DuPont Toray Co., Ltd.).
• Example 11 The coverlay film was produced in the same manner as in Example 1.
• the oxygen permeability at 30° C. was measured in accordance with ASTM D1434, the same as in Example 1.
• the peel strength was measured in the same manner as in Example 1. The measurement results are shown in Tables 1 and 2.
• thermosetting resin composition constituting the adhesive layer had excellent adhesiveness because, relative to 100 parts by mass of polyamideimide resin, the content of non-solid epoxy resin at 25°C was 30 parts by mass to 70 parts by mass, the content of fine particle rubber was 5 parts by mass to 20 parts by mass, and the content of inorganic filler was 20 parts by mass to 40 parts by mass.
• Example 11 The sample of Example 11 was left in the high temperature atmosphere for an extended period of time, and the peel strength was then measured. Specifically, the peel strength was measured after leaving the sample in a 150°C atmosphere for 500 hours and storing it at 25°C and 50% relative humidity for 24 hours, and after leaving the sample in a 150°C atmosphere for 1000 hours and storing it at 25°C and 50% relative humidity for 24 hours. The results were as follows. (Example 11) (1) 150°C, 500 hours Coverlay film peel strength 10.5N/cm, Peel strength of adherend: 9.8 N/cm. (2) 150°C, 1000 hours Coverlay film peel strength 9.5N/cm, Peel strength of adherend: 8.5 N/cm.
• the reasons for the high peel strength include the fact that the coverlay film, which has a polyimide film laminated with a gas barrier layer, reduces oxygen transmission and reduces deterioration of the adhesive layer due to oxygen, and the fact that an inorganic filler is present in the thermosetting resin composition, which has high heat resistance.
• cohesive failure was confirmed in the sample of Example 11 at the interface between the adherend and the adhesive layer after the peel strength measurement, and at the interface between the polyimide film and the adhesive layer after the peel strength measurement.
• the coverlay films having an adhesive layer composed of the thermosetting resin compositions of Examples 1 to 11 had excellent adhesion in both the coverlay film and the adherend, even when placed in a high-temperature environment for a long period of time. Furthermore, Example 11 had excellent adhesion in both the coverlay film and the adherend, even when placed in a high-temperature environment for 500 hours and 1000 hours.
• Such a coverlay film is suitable as a coverlay film for use in in-vehicle electronic devices.
• Appendix 1 A polyamide-imide resin having an acrylonitrile-butadiene rubber skeleton; an epoxy resin that is non-solid at 25°C; fine particle rubber dispersed in the non-solid epoxy resin; An inorganic filler; A curing agent, the content of the non-solid epoxy resin is 30 parts by mass or more and 70 parts by mass or less relative to 100 parts by mass of the polyamide-imide resin, The content of the fine particle rubber is 5 parts by mass or more and 20 parts by mass or less with respect to 100 parts by mass of the polyamide-imide resin, The thermosetting resin composition, wherein the inorganic filler is contained in an amount of 20 parts by mass or more and 40 parts by mass or less relative to 100 parts by mass of the polyamideimide resin.
• thermosetting resin composition according to claim 1 wherein the fine particle rubber comprises a core layer and a shell layer covering the surface of the core layer.

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