Laminated film, laminate, and method for producing the same

Abstract

To provide a laminated film having superior initial adhesion with an object, and also capable of retaining adhesion even in a hot and humid environment.SOLUTION: Provided is a laminated film comprising, on at least one surface of a base material, either a resin layer X or a resin layer Y, the laminated film meeting one of the following conditions: Condition 1: the resin layer X comprises a nadimide compound and a carbodiimide compound. Condition 2: the resin of the base material is at least one resin selected from aromatic polyamide, polyphenylene sulfide, liquid crystal polyester, polyether ether ketone, and polyetherimide, and the resin layer Y comprises a nadimide compound.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a laminate film, a laminate, and a method for producing the same. [Background technology]

[0002] Films, particularly biaxially oriented polyester films, are widely used as substrate films in many applications, such as magnetic recording materials and packaging materials, due to their excellent mechanical properties, electrical properties, dimensional stability, transparency, and chemical resistance. In particular, in recent years, demand has been increasing for applications such as insulating films, heat-resistant films, bonding substrates, protective films for semiconductor devices, heat-resistant tapes, circuit components, battery components, and automotive applications. These applications often involve coating processes or lamination of electrode materials or optical films to impart various functions. Therefore, it is common to provide polyester films with an easy-adhesion layer to improve adhesion. Meanwhile, such films are increasingly required to have adhesion properties in humid and heat-resistant environments (humid and heat-resistant adhesion) in terms of their composition and material structure. To meet these requirements, an invention has been disclosed that uses a polyester resin with a fluorene skeleton to improve humidity and heat-resistant adhesion, as an approach from the adhesion layer side (Patent Document 1). Furthermore, an optical easy-adhesion polyester film with excellent humidity and heat-resistant adhesion has been disclosed, using a specific water-soluble polyester (Patent Document 2).

[0003] Also, a laminated polyester film with excellent anti-reflection properties has been disclosed, which is produced by laminating a coating agent containing an alkenyl-substituted nadimide having excellent heat resistance onto a base polyester film and drying it (Patent Document 3). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2014-28522 [Patent Document 2] Japanese Patent Application Laid-Open No. 2006-215107 [Patent Document 3] Japanese Patent Application Laid-Open No. 2011-42177 Summary of the Invention [Problem to be solved by the invention]

[0005] In recent years, there has been a demand for high-temperature, heat-resistant adhesive properties that can maintain adhesion under even harsher conditions, such as a humid and hot atmosphere of 120°C.

[0006] However, the adhesive resins used in Patent Documents 1 and 2 are polyester resins, which deteriorate in an atmosphere with a temperature exceeding 120° C., which poses a problem in terms of long-term adhesion. Moreover, the adhesive resin used in Patent Document 3 does not have sufficient long-term adhesion at temperatures exceeding 120° C.

[0007] Meanwhile, in the course of research, the present inventors have found that providing a resin layer in which a nadimide compound is combined with a specific crosslinking agent, or combining a resin layer using a nadimide compound with a heat-resistant substrate, significantly improves long-term adhesion in a humid and hot environment, as described below.

[0008] Therefore, the present invention aims to eliminate the above-mentioned drawbacks and provide a laminated film that has good initial adhesion between the resin layer and the functional layer described below and can maintain long-term adhesion in a humid and hot atmosphere at 120°C. [Means for solving the problem]

[0009] The present invention has the following features: A laminate film having a resin layer X or a resin layer Y on at least one surface of a substrate, and satisfying either of the following conditions 1 or 2: Condition 1: The resin layer X contains a nadimide compound and a carbodiimide compound. Condition 2: The resin of the substrate is at least one resin selected from the group consisting of aromatic polyamide, polyphenylene sulfide, liquid crystal polyester, polyether ether ketone, and polyether imide, and the resin layer Y contains a nadimide compound.

[0010] The laminated film of the present invention can have the following embodiments and can also be produced by the following production method.

[0011] (1) A laminated film having a resin layer X or a resin layer Y on at least one surface of a substrate, which meets either of the following conditions 1 or 2: Condition 1: The resin layer X contains a nadimide compound and a carbodiimide compound. Condition 2: The resin of the substrate is at least one resin selected from the group consisting of aromatic polyamide, polyphenylene sulfide, liquid crystal polyester, polyether ether ketone, and polyether imide, and the resin layer Y contains a nadimide compound.

[0012] (2) The laminated film according to (1), wherein the surface free energy of the resin layer X or the resin layer Y is 35.0 mN / m or more and 55.0 mN / m or less.

[0013] (3) A laminate film according to (1) or (2), which has a resin layer X on at least one surface of a substrate and satisfies the following condition 1-2: Condition 1-2: The resin layer X contains a nadimide compound, a carbodiimide compound, and an oxazoline compound.

[0014] (4) A laminate film according to any one of (1) to (3), which has a resin layer X on at least one surface of a substrate and satisfies the following conditions 1-3: Condition 1-3: The resin layer X contains a nadimide compound and a carbodiimide compound, and the resin of the substrate is at least one resin selected from the group consisting of aromatic polyamide, polyphenylene sulfide, liquid crystal polyester, polyether ether ketone, and polyetherimide.

[0015] (5) A laminate having a functional layer on the surface of the laminate film according to any one of (1) to (4) on the side of the resin layer X or the resin layer Y.

[0016] (6) The laminate according to (5), wherein the functional layer is any one of a hard coat layer, an adhesive layer, an ink layer, and an adhesive layer.

[0017] (7) The laminated film according to any one of (1) to (6) above, which is used as an insulating film, a heat-resistant film, a bonding substrate, a protective film for semiconductor elements, a heat-resistant tape, a circuit member, or a battery member.

[0018] (8) The laminate film according to any one of (1) to (6), which is used for a film for an in-vehicle display or a film for an in-vehicle electronic component.

[0019] (9) A gasket having the laminated film according to (1) and an adhesive layer.

[0020] (10) A fuel cell having the gasket according to (9).

[0021] (11) A method for producing a laminated film having a resin layer X or a resin layer Y on at least one surface of a substrate, which satisfies either of the following conditions 1 or 2, and which includes a step of forming the resin layer X or the resin layer Y by thermally curing a coating composition at 180°C or higher: Condition 1: The resin layer X contains a nadimide compound and a carbodiimide compound. Condition 2: The resin of the substrate is at least one selected from the group consisting of aromatic polyamide, polyphenylene sulfide, liquid crystal polyester, polyether ether ketone, and polyetherimide, and the resin layer Y contains a nadimide compound.

[0022] (12) A method for producing a laminate, comprising the step of forming a functional layer on the surface of the laminate film obtained by the production method according to (11) on the side of the resin layer X or the resin layer Y.

[0023] (13) The method for producing a laminate according to (12), wherein the functional layer is any one of a hard coat layer, an adhesive layer, an ink layer, and an adhesive layer. [Effects of the Invention]

[0024] According to the present invention, it is possible to provide a laminated film that has good initial adhesion and long-term adhesion under heat and humidity conditions to various hard coating materials, pressure sensitive adhesives, ink layers, and adhesive layers. DETAILED DESCRIPTION OF THE INVENTION

[0025] The laminate film of the present invention is described in detail below. The laminate film of the present invention is a laminate film having a resin layer X or a resin layer Y on at least one side of a substrate, and satisfies either condition 1 or 2 below. Condition 1: The resin layer X contains a nadimide compound and a carbodiimide compound. Condition 2: The resin of the substrate is at least one resin selected from the group consisting of aromatic polyamide, polyphenylene sulfide, liquid crystal polyester, polyether ether ketone, and polyether imide, and the resin layer Y contains a nadimide compound.

[0026] The resin layer X and the resin layer Y will be described in detail below.

[0027] (Resin layer X) The resin layer X of the present invention must contain a nadimide compound as a binder resin. When the resin layer X contains such a nadimide compound, it will have excellent long-term adhesion at high temperatures.

[0028] The nadimide compound of the present invention is a compound having at least one nadimide group represented by the following formula (1).

[0029] [ka]

[0030] In the above formula (1), R 1 and R 2 represents a hydrogen atom, an alkyl group such as a methyl group, or an alkenyl group, and may be the same or different. The number n ranges from 1 to 2, and it is particularly preferable that the number n is 2. When the number n is 1, R 3 represents an alkyl group having 1 to 12 carbon atoms, an alkenyl group having 3 to 6 carbon atoms, a cycloalkyl group having 5 to 8 carbon atoms, a monovalent aromatic group having 6 to 12 carbon atoms, or a benzyl group.

[0031] When the number n is 2, the nadimide compound is represented by the following formula (2).

[0032] [ka]

[0033] Also, when n is 2, R 3 is preferably a phenyl group represented by the following formula (3).

[0034] [ka]

[0035] The nadimide compound used in the present invention is not limited to these. These nadimide compounds may be used alone or in combination. By including these nadimide compounds in the resin layer X, the resin layer X itself becomes excellent in heat resistance.

[0036] A specific example of a nadimide compound is the "Rezem" (registered trademark) IM series, an aqueous emulsion of bisallylnadimide, a thermosetting imide manufactured by Chukyo Yushi. The model number to be used can be selected based on the heat resistance of the base resin. For example, when using polyester resins, polyethylene (PE) resins, polypropylene (PP) resins, polystyrene resins, polyolefin resins such as cyclic olefin resins, vinyl resins such as polyvinyl chloride and polyvinylidene chloride, and polyamide resins, IM-N159 and IM-N160, which have a curing temperature of 160 to 180°C, are suitable. IM-3, which has a curing temperature of 250°C, is suitable for base resins such as aromatic polyamides, polyphenylene sulfide, liquid crystal polyesters, polyether ether ketones, and polyetherimides. Selecting a nadimide compound appropriate for the base resin prevents insufficient adhesion due to insufficient curing temperature, or thermal deformation of the base material even when the curing temperature is sufficient, making this a suitable choice.

[0037] Although resins other than nadimide compounds may be mixed as the binder resin, from the viewpoint of maintaining moisture- and heat-resistant adhesion and heat-resistant adhesion, it is preferable that 30% by mass or more of the binder resin in the resin layer X is a nadimide compound. Having a nadimide compound content of 30% by mass or more results in excellent moisture- and heat-resistant adhesion at 120°C. It is particularly preferably 50% by mass or more, more preferably 70% by mass or more. Examples of binder resins used other than nadimide compounds include acrylic resins, polyester resins, and urethane resins, with polyester resins being the most preferred. Furthermore, when polyester resins are used as aqueous coating liquids, it is preferable to copolymerize them with compounds containing sulfonate groups or carboxylate groups to facilitate water solubility or water dispersion of the polyester resin. The binder resin refers to a resin that accounts for 50% by mass or more of the resin layer X, and does not include crosslinking agents or particles.

[0038] The resin layer X of the present invention must contain a carbodiimide compound. The above requirement can be satisfied even when the carbodiimide compound reacts with a binder resin such as a nadiimide compound or other crosslinker compound to form a new chemical structure. The above requirement can also be satisfied even when the carbodiimide compound incorporated into the coating composition remains unreacted after the resin layer X has cured. A carbodiimide compound is a compound having at least one carbodiimide group or a tautomeric cyanamide group as a functional group in the molecule. Specific examples of such carbodiimide compounds include dicyclohexylmethanecarbodiimide, dicyclohexylcarbodiimide, tetramethylxylylenecarbodiimide, and urea-modified carbodiimide. These may be used alone or in combination. The inclusion of a carbodiimide compound improves adhesion between the resin layer X and the functional layer, and between the resin layer X and the substrate.

[0039] Specific polycarbodiimide compounds include "Carbodilite" (registered trademark) V-02, "Carbodilite" (registered trademark) V-02-L2, "Carbodilite" (registered trademark) SV-02, and "Carbodilite" (registered trademark) V-04 (all manufactured by Nisshinbo Industries, Inc.), which have little coloring and excellent adhesion.

[0040] The coexistence of a nadimide compound and a carbodiimide compound results in excellent heat- and moisture-resistant adhesion and heat-resistant adhesion. The preferred blending ratio of the nadimide compound and the carbodiimide compound is 10 to 50 parts by mass, and more preferably 15 to 30 parts by mass, of the carbodiimide per 100 parts by mass of the nadimide compound. By setting the blending ratio within the above range, good heat- and moisture-resistant adhesion and heat-resistant adhesion can be achieved. (Resin layer Y) The resin layer Y of the present invention must contain a nadimide compound as a binder resin. The nadimide compound can be the compounds described in the section on resin layer X. Furthermore, the substrate to which the resin layer Y is applied must be at least one resin selected from aromatic polyamide, polyphenylene sulfide, liquid crystal polyester, polyether ether ketone, and polyetherimide. The substrate shown here exhibits excellent adhesion even without the inclusion of a carbodiimide compound. The reason for this effect is believed to be that the substrate reacts with the nadimide compound to bond to it. In particular, the adhesion to polyphenylene sulfide and polyetherimide substrates is excellent. Polyphenylene sulfide is particularly preferred because it can be biaxially stretched and has excellent heat resistance and adhesion.

[0041] In the laminate film of the present invention, the surface free energy of the resin layer X or resin layer Y is preferably 35.0 mN / m or more and 55.0 mN / m or less. It is more preferably 40.0 mN / m or more and 55.0 mN / m or less, even more preferably 45.0 mN / m or more and 55.0 mN / m or less, and most preferably 45.0 mN / m or more and 50.0 mN / m or less. By setting the surface free energy within the range of 35.0 mN / m or more and 55.0 mN / m or less, a coating agent applied to the resin layer X or resin layer Y tends to instantly become wet, making it easier to develop good coating properties. Furthermore, after the drying process, the coating agent in contact with the resin layer X or resin layer Y adheres tightly to each other, making it easier to develop good adhesion.

[0042] The laminate film of the present invention, which has a resin layer X on at least one surface of a substrate, preferably satisfies the following condition 1-2. Condition 1-2: The resin layer X contains a nadimide compound, a carbodiimide compound, and an oxazoline compound. The above requirement can also be considered to be satisfied when a binder resin such as a nadimide compound or another crosslinker compound reacts with an oxazoline compound to form a new chemical structure. Furthermore, the above requirement can also be considered to be satisfied when an oxazoline compound incorporated into a coating composition remains unreacted after the resin layer X is cured. The oxazoline compound preferably has an oxazoline group as a functional group within the compound, and is an oxazoline group-containing copolymer obtained by copolymerizing at least one monomer containing an oxazoline group with at least one other monomer.

[0043] In the oxazoline compound, at least one other monomer used for the monomer containing an oxazoline group is a monomer copolymerizable with the monomer containing an oxazoline group, and examples thereof include acrylic acid esters or methacrylic acid esters such as methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, butyl acrylate, butyl methacrylate, 2-ethylhexyl acrylate, and 2-ethylhexyl methacrylate, unsaturated carboxylic acids such as acrylic acid, methacrylic acid, itaconic acid, and maleic acid, acrylonitrile, and methacrylonitrile. unsaturated nitriles such as those mentioned above, unsaturated amides such as acrylamide, methacrylamide, N-methylolacrylamide, and N-methylolmethacrylamide, vinyl esters such as vinyl acetate and vinyl propionate, vinyl ethers such as methyl vinyl ether and ethyl vinyl ether, olefins such as ethylene and propylene, halogen-containing α,β-unsaturated monomers such as vinyl chloride, vinylidene chloride, and vinyl fluoride, and α,β-unsaturated aromatic monomers such as styrene and α-methylstyrene, and the like can be used alone or in combination.

[0044] Specific oxazoline compounds are not particularly limited, but addition-polymerizable oxazoline group-containing monomers are preferred, such as 2-vinyl-2-oxazoline, 2-vinyl-4-methyl-2-oxazoline, 2-vinyl-5-methyl-2-oxazoline, 2-isopropenyl-2-oxazoline, 2-isopropenyl-4-methyl-2-oxazoline, and 2-isopropenyl-5-ethyl-2-oxazoline. These may be used alone or in combination.

[0045] The coexistence of a nadimide compound, a carbodiimide compound, and an oxazoline compound results in the most excellent heat- and humidity-resistant adhesion and heat-resistant adhesion. A preferred blending ratio of the nadimide compound, the carbodiimide compound, and the oxazoline compound is 10 to 50 parts by mass of the carbodiimide and 5 to 25 parts by mass of the oxazoline compound, more preferably 15 to 30 parts by mass of the carbodiimide and 7.5 to 12.5 parts by mass of the oxazoline compound, per 100 parts by mass of the nadimide compound. In this case, it is preferable that the ratio of the carbodiimide parts by mass is greater than the ratio of the oxazoline compound parts by mass.

[0046] In the laminate film of the present invention, the thickness of the resin layer X or the resin layer Y is preferably 30 nm or more and 800 nm or less. By making the thickness of the resin layer X or the resin layer Y 30 nm or more, it is possible to impart easy adhesion. Furthermore, if the thickness of the resin layer X or the resin layer Y is too thick, the film will curl, so by making the thickness of both resin layers X 800 nm or less, preferably 750 nm or less, more preferably 100 nm or less, and particularly preferably 80 nm or less, it is possible to improve curl resistance.

[0047] (Film substrate) The laminated film of the present invention uses, as its base resin, polyester-based resins such as polyethylene terephthalate (PET) and modified polyester; polyolefin resins such as polyethylene (PE) resin, polypropylene (PP) resin, polystyrene resin, and cyclic olefin-based resin; vinyl-based resins such as polyvinyl chloride and polyvinylidene chloride; and polyamide resins. These materials may be used alone or in combination of two or more. Polyester-based resins are particularly preferred due to their excellent film-forming properties, transparency, heat resistance, moist heat resistance, and chemical resistance. Polyester is a general term for polymers whose main bonding chain is an ester bond. Polyesters containing at least one component selected from ethylene terephthalate, propylene terephthalate, ethylene-2,6-naphthalate, butylene terephthalate, propylene-2,6-naphthalate, and ethylene-α,β-bis(2-chlorophenoxy)ethane-4,4'-dicarboxylate are preferred.

[0048] Here, the term "major component" refers to a component that accounts for more than 70 mol% and not more than 100 mol%, when the total component units constituting the resin are taken as 100 mol%. Furthermore, the term "laminated polyester film" refers to a sheet-like material having at least two layers and containing polyester as the main component. The term "main component" refers to a component that accounts for more than 50 mass% and not more than 100 mass% of the total components. The term "polyester substrate" refers to a sheet-like material that constitutes the laminated polyester film and that contains polyester as the main component. Furthermore, the polyester may contain not more than 30 mol% of a copolymer component in the total components as necessary. From the viewpoints of heat resistance and smoothness, it is preferable to use a polyethylene terephthalate film as the polyester substrate in the laminate film of the present invention.

[0049] Furthermore, although the base resins described above are fine in an atmosphere of 120°C or less, if they are exposed to an atmosphere of 150°C or higher for a long period of time, the resins may deteriorate thermally and become unsuitable for use in the final product. When using them in a high-temperature atmosphere of 150°C or higher, it is preferable that the following conditions 1-3 are met. Condition 1-3: The resin layer X contains a nadimide compound and a carbodiimide compound, and the resin of the substrate is at least one resin selected from the group consisting of aromatic polyamide, polyphenylene sulfide, liquid crystal polyester, polyether ether ketone, and polyetherimide. These resins are generally called super engineering plastic resins, and they maintain their film strength with little deterioration even in high-temperature environments of 150° C. or higher. The resin layer X of the present invention exhibits high adhesive strength to many of these super engineering plastic resins and also has high heat resistance.

[0050] The aromatic polyamide is composed of an aromatic dicarboxylic acid component and an aliphatic diamine component. The aromatic dicarboxylic acid component preferably contains 60 mol% or more, more preferably 70 mol% or more, and even more preferably 85 mol% or more of terephthalic acid. If the terephthalic acid content is less than 60 mol%, the heat resistance and low water absorbency of the resulting film will be reduced.

[0051] As the aromatic polyamide, commercially available products can be suitably used, such as "Genestar" (registered trademark) manufactured by Kuraray Co., Ltd., "Zecot" (registered trademark) manufactured by Unitika Ltd., "Reny" (registered trademark) manufactured by Mitsubishi Engineering Plastics Corporation, "Arlen" (registered trademark) manufactured by Mitsui Chemicals, Inc., and "Ultramid" (registered trademark) manufactured by BASF.

[0052] Polyphenylene sulfide (hereinafter also referred to as PPS) is a polymer containing 70 mol % or more, more preferably 90 mol % or more, of repeating units represented by structural formula (4). A content of less than 70 mol % of the repeating units is undesirable because it impairs heat resistance. Furthermore, PPS can be copolymerized with copolymerization units in a range of 0.01 mol % or more but less than 30 mol % of the repeating units. The repeating units having copolymerizable sulfide bonds are not limited, but aromatic sulfides represented by the following structural formula (5) are particularly preferred. One of these repeating units may be contained alone, or two or more may be contained in combination. The copolymerization form of the polymer may be either a random polymer or a block polymer.

[0053] [ka]

[0054] [ka]

[0055] Liquid crystal polyester resins are polyesters that form an anisotropic melt phase. Examples of such polyester resins include polyesters composed of structural units selected from oxycarbonyl units, dioxy units, dicarbonyl units, etc., so as to form an anisotropic melt phase.

[0056] Commercially available liquid crystal polyesters can be suitably used, such as "Sumikasuper LCP" (registered trademark) manufactured by Sumitomo Chemical Co., Ltd., "Laperus" (registered trademark) manufactured by Polyplastics Co., Ltd., and "Scivelas" (registered trademark) manufactured by Toray Industries, Inc.

[0057] Polyether ether ketone is a crystalline thermoplastic resin with a linear polymer structure in which benzene rings are bonded by two ether and ketone groups.

[0058] Commercially available polyether ether ketones can be suitably used, such as "Victrex Peak" (registered trademark) manufactured by Victrex, "Vestakeep" (registered trademark) manufactured by Daicel-Evonik, and "KetaSpire" (registered trademark) manufactured by Solvays Specialty Polymers.

[0059] Any known polyetherimide can be used without any particular limitation, and a specific example is "Ultem" (registered trademark) manufactured by SABIC Innovative Plastics Japan.

[0060] The film may contain various additives, such as antioxidants, heat stabilizers, weather stabilizers, ultraviolet absorbers, organic lubricants, pigments, dyes, organic or inorganic fine particles, fillers, antistatic agents, nucleating agents, etc., to the extent that they do not deteriorate the properties of the film.

[0061] The thickness of the film is not particularly limited and may be appropriately selected depending on the application and type, but is preferably 10 μm or more and 150 μm or less.

[0062] The laminate film of the present invention is preferably a laminate having a functional layer on the surface of the laminate film facing the resin layer X or resin layer Y. Examples of the functional layer include a retardation layer, a hard coat layer, an antiglare layer, an antireflection layer, an antifouling layer, an ultraviolet absorber layer, an electromagnetic wave blocking layer, a release layer, a printing layer, a gas barrier layer, an antistatic layer, and an adhesive layer. The functional layer may have multiple functions. In the most preferred embodiment of the present invention, the functional layer is a hard coat layer, and the film substrate preferably has scratch resistance against external scratches and indentation.

[0063] The thickness of the functional layer is 0.05 μm to 3 mm, and more preferably 0.2 μm to 1 mm. The presence or absence and thickness of the functional layer can be confirmed by observation with a transmission electron microscope. When observed with a transmission electron microscope at a magnification of 50,000 times or more, the film substrate exhibits fine variations in shade due to a lamellar structure associated with biaxial orientation in which crystalline and amorphous portions are intermixed, whereas such fine variations in shade are not observed in resin layer X or resin layer Y, and this can be determined.

[0064] The laminated film of the present invention is preferably used as an insulating film, heat-resistant film, bonding substrate, protective film for semiconductor devices, heat-resistant tape, circuit components, or battery components. The term "insulating film" refers to, for example, interlayer insulating materials used to protect high-performance semiconductors, printed circuit board packages, high-frequency antenna package molding materials, low-dielectric constant films, coil coating materials, and motor slot inner materials. The term "bonding substrate" refers to film-like adhesives used to bond semiconductor chips to substrates or to bond semiconductor chips to each other. The term "protective film for semiconductor devices" refers to conductive films that suppress electrostatic discharge, which can cause deterioration of semiconductor devices. Heat-resistant tapes are used, for example, for securing aluminum electrolytic capacitors, which require heat resistance, and for insulating electrodes in lithium-ion secondary batteries. Circuit boards are substrates for connecting electronic components to form electrical circuits, and are particularly useful in communication devices and automobiles, which require heat resistance. The term "battery components" refers to gaskets, separators, hydrogen hoses, gas filters, and other components used in fuel cells. These applications require greater heat resistance than ever before due to the high integration of components, and by applying the laminated film of the present invention, heat-resistant adhesion can be maintained for a long period of time.

[0065] The laminate film of the present invention is suitable for use as a film for an in-vehicle display or a film for an in-vehicle electronic component. Examples of films for in-vehicle displays include a center information display (CID), a meter craft panel (MCP), and a head-up display (HUD). Because there is little decrease in adhesion between the adhesive layer and the functional layer in a humid and hot atmosphere at 120°C, the laminate film of the present invention is suitable for applications requiring heat and transparency. Specifically, the laminate film of the present invention can be used in applications where a hard coat layer or a conductive layer such as indium tin oxide (hereinafter referred to as ITO) is provided on the laminate film (e.g., touch panel applications).

[0066] The laminated film of the present invention can be suitably used as a gasket (also called a subgasket) having an adhesive layer laminated on the laminated film. A gasket refers to a member punched into a frame or picture frame shape.

[0067] The gasket of the present invention has excellent heat resistance and can therefore be suitably used as a fuel cell component. The cell used in a fuel cell has a structure in which a catalyst layer, an electrode substrate, and a separator are sequentially laminated on both sides of an electrolyte membrane reinforced with the gasket of the present invention. Of these, a CCM in which a catalyst layer is laminated on both sides of an electrolyte membrane (i.e., a layer structure of catalyst layer / electrolyte membrane / catalyst layer) is called a catalyst-coated electrolyte membrane (CCM), and a CCM in which a catalyst layer and a gas diffusion substrate are sequentially laminated on both sides of an electrolyte membrane (i.e., a layer structure of gas diffusion substrate / catalyst layer / electrolyte membrane / catalyst layer / gas diffusion substrate) is called a membrane electrode assembly (MEA).

[0068] Common methods for manufacturing a CCM include a coating method in which a catalyst layer paste composition for forming a catalyst layer is applied to the surface of an electrolyte membrane and dried, and a method (transfer method) in which only the catalyst layer is prepared on a substrate and then this catalyst layer is transferred to laminate the catalyst layer on the electrolyte membrane. The edge of the electrolyte membrane in this CCM is placed on the periphery of the opening of the film of the present application to which a frame-shaped cutout sealing material has been applied, and the CCM and gasket are attached by heat pressing.

[0069] When fabricating an MEA by pressing, known methods (e.g., the chemical plating method described in Electrochemistry, 1985, 53, p. 269, or the hot press bonding method for gas diffusion electrodes described in Electrochemical Science and Technology, edited by the Electrochemical Society (J. Electrochem. Soc.), 1988, 135, 9, p. 2209) can be used. The temperature and pressure during pressing can be appropriately selected depending on the thickness and moisture content of the electrolyte membrane, the catalyst layer, and the electrode substrate. Specific pressing methods include roll pressing with a specified pressure and clearance, and plate pressing with a specified pressure. From the viewpoints of industrial productivity and suppression of thermal decomposition of polymer materials having ionic groups, pressing is preferably performed at a temperature in the range of 0 to 250°C.

[0070] In a fuel cell having the above-described configuration, the gasket of the present invention is preferably used by adhering it to the peripheral portion of the electrolyte membrane. The frame-shaped gasket has a central portion where the electrodes are stacked cut out in the shape of the electrodes, with the gasket present only on the peripheral portion. A preferred embodiment of the gasket is one in which two or more adhesive layers are superimposed. Specifically, one embodiment includes one in which the peripheral portion of the electrolyte membrane is sandwiched between the gaskets, with two gaskets used on each side of the electrolyte membrane. In particular, a configuration in which a resin layer Y is laminated on a polyphenylene sulfide substrate is preferred because it has excellent electrolyte resistance and adhesion even in a high-temperature atmosphere.

[0071] (Laminated film manufacturing method) The laminated film of the present invention will be described in more detail below using an example in which the base film is polyethylene terephthalate (hereinafter referred to as PET). First, PET pellets are thoroughly vacuum-dried to reduce the moisture content to 100 ppm or less and then fed into an extruder. The extruder melt-extrudes the material into a sheet at approximately 280°C, and the sheet is cooled and solidified on a cast drum with a surface temperature of 5 to 40°C to produce an unstretched (unoriented) PET film (Film A). This Film A is stretched 2.5 to 5.0 times in the longitudinal direction using a roll heated to 80 to 120°C to obtain a uniaxially oriented PET film (Film B). The edges of Film B are held with clips and introduced into a tenter, where it is heated to 80 to 130°C and then stretched 1.1 to 5.0 times in the transverse direction. The film is then introduced into a heat treatment zone at 150 to 250°C for 1 to 30 seconds to complete the crystal orientation. In this heating step (heat treatment step), a relaxation treatment of 3 to 15% may be carried out in the width direction or the length direction, if necessary. In this way, the polyester film constituting the laminated film of the present invention can be obtained.

[0072] The substrate film of the present invention is preferably biaxially oriented. A biaxially oriented film generally refers to a film obtained by stretching an unstretched sheet or film by about 2.5 to 5.0 times in both the longitudinal direction and the width direction perpendicular to the longitudinal direction, and then heat-treating the film to complete the crystal orientation, and which exhibits a biaxially oriented pattern in wide-angle X-ray diffraction. A biaxially oriented film is preferred because it improves the thermal stability, particularly dimensional stability and mechanical strength, and flatness of the laminated film.

[0073] (Method of forming resin layer X) The method for forming a resin layer X of the present invention preferably includes a step of forming a resin layer X containing a nadimide compound and a carbodiimide compound on at least one surface of a substrate by thermally curing a coating composition at 180°C or higher to form the resin layer X.

[0074] If the curing temperature is 180°C or higher, the nadimide compound will adhere firmly to the substrate. There is no particular upper limit on the temperature, but it is recommended that it be below the heat distortion temperature of the substrate used. If the film is significantly deformed by heat treatment, it will no longer be applicable to the above-mentioned product groups.

[0075] (Method of forming resin layer Y) The method for forming a resin layer Y of the present invention preferably includes a step of forming a resin layer Y containing a nadimide compound on at least one surface of a substrate selected from at least one of aromatic polyamide, polyphenylene sulfide, liquid crystal polyester, polyether ether ketone, and polyetherimide, and forming the resin layer X by thermally curing a coating composition at 180°C or higher.

[0076] In the present invention, the formation of the resin layer X or the resin layer Y can be carried out by either an in-line coating method in which a dispersion of the resin layer X or the resin layer Y is applied simultaneously with the formation of the base film, or an off-line coating method in which the base film is formed, then rewound, and the dispersion of the resin layer X or the resin layer Y is applied thereto. However, the in-line coating method is preferred because of its advantages in productivity and the ability to set a high curing temperature.

[0077] In the case of in-line coating, a dispersion of resin layer X or resin layer Y is applied onto a substrate film stretched in the longitudinal direction, and then the film is laterally gripped and stretched in the width direction with a tenter, and finally dried at a temperature range of 180°C or higher, or 250°C or lower in the case of a polyester film, to form resin layer X or resin layer Y, and then wound up.

[0078] The coating method for the film can be any known coating method, such as bar coating, reverse coating, gravure coating, die coating, blade coating, or the like.

[0079] The thickness of resin layer X or resin layer Y is proportional to the concentration of the coating composition and the coating thickness, and inversely proportional to the widthwise stretching ratio and the specific gravity of resin layer X or resin layer Y. Of these, the coating thickness is uniquely determined by the count used for bar coating, and the stretching ratio is uniquely determined by the film-forming conditions. Therefore, by preparing multiple concentrations of the coating composition in advance and measuring the thickness of resin layer X or resin layer Y using the method described above, a calibration curve can be created, and the concentration of the coating composition that matches the target thickness of resin layer X or resin layer Y can be determined.

[0080] The laminated film thus obtained has good adhesion when a functional layer is provided on the surface of the resin layer X or the resin layer Y, and can suppress deterioration of adhesion even when kept in a humid and hot atmosphere at 120°C for a long period of time.

[0081] The functional layer provided on the laminated film is preferably any one of a hard coat layer, an adhesive layer, an ink layer, and an adhesive layer.

[0082] The first hard coat layer is laminated on the laminate film, thereby providing the film substrate with scratch resistance against external abrasions and pressure.

[0083] In the present invention, examples of the resin forming the hard coat layer include radically polymerizable compounds such as oligomers, prepolymers, and monomers of polyester resins, acrylic resins, and urethane resins having an acryloyl group, as well as cationic polymerizable compounds such as oligomers, prepolymers, and monomers containing an epoxy ring, an oxetane ring, or a vinyl ether group. These resins are crosslinked by the application of energy such as heat, ultraviolet light, or an electron beam. In the present invention, resins that are crosslinked by heat are preferred, but resins that combine the properties of both may also be used.

[0084] Preferred resins for forming the hard coat layer are those that are resistant to curling and have good adhesion to the substrate, and examples thereof include low-shrinkage urethane acrylates and epoxy compounds. Specific examples of urethane acrylates include AT-600, UA-1011, UF-8001, UF-8003, etc. manufactured by Kyoeisha Chemical Co., Ltd., UV7550B, UV-7600B, etc. manufactured by Nippon Synthetic Chemical Industry Co., Ltd., U-2PPA, UA-NDP, etc. manufactured by Shin-Nakamura Chemical Co., Ltd., Ebecryl-270, Ebecryl-284, Ebecryl-264, Ebecryl-9260, etc. manufactured by Daicel-UCB Co., Ltd., and specific examples of epoxy compounds include EHPE3150, GT300, GT400, Celoxide 2021, etc. manufactured by Daicel Chemical Industries, Ltd., and EX-321, EX-411, EX-622, etc. manufactured by Nagase Chemtec Corporation. However, examples thereof are not limited thereto. Among urethane acrylates that can achieve higher hardness, urethane acrylate oligomers and monomers can be obtained by reacting a polyhydric alcohol, a polyisocyanate, and a hydroxyl group-containing acrylate. Specific examples include UA-306H, UA-306T, UA-3061, etc. manufactured by Kyoeisha Chemical Co., Ltd., UV-1700B, UV-6300B, UV-7600B, UV-7605B, UV-7640B, UV-7650B, etc. manufactured by Nippon Synthetic Chemical Industry Co., Ltd., U-4HA, U-6HA, UA-100H, U-6LPA, U-15HA, UA-32P, U-324A, etc. manufactured by Shin-Nakamura Chemical Co., Ltd., Ebecryl-1290, Ebecryl-1290K, Ebecryl-5129, etc. manufactured by Daicel-UCB Ltd., and UN-3220HA, UN-3220HB, UN-3220HC, UN-3220HS, etc. manufactured by Negami Chemical Industrial Co., Ltd. However, the present invention is not limited to these.

[0085] Furthermore, by laminating the second adhesive layer on the laminate film, the film substrate can be easily adhered to the target object. In the present invention, the resin forming the adhesive layer is preferably a silicone resin having an organopolysiloxane structure. Silicone resins can be used for heat-resistant adhesive layers that do not blister even when subjected to high-temperature treatment and maintain good peelability. In particular, organopolysiloxanes have at least one, preferably two or more, alkenyl groups bonded to silicon atoms per molecule. Typically, the main chain is basically composed of repeating diorganosiloxane units, but the molecular structure may contain a branched structure or may be cyclic. In particular, linear diorganopolysiloxanes are preferred from the perspective of physical properties such as the mechanical strength of the cured product. The alkenyl group preferably has 2 to 8 carbon atoms, and examples thereof include vinyl, allyl, propenyl, isopropenyl, butenyl, hexenyl, and cyclohexenyl groups. Among these, vinyl groups and lower alkenyl groups such as allyl groups are preferred, with vinyl groups being particularly preferred.

[0086] Furthermore, the third ink layer is the colorant layer of the thermal transfer recording material, a heat-melting colorant layer whose main components are colorants such as carbon black and organic pigments, wax, and polymers, and can be layered on top of the laminated film to add decorative properties.

[0087] The ink layer is composed of a polymer such as an acrylic resin, a cellulose resin, a urethane resin, a polyester resin, or an epoxy resin, or a reactive monomer such as a monomer having at least one ionizing radiation-curable functional group selected from vinyl, (meth)acryloyl, allyl, and epoxy groups, for example, a polyfunctional (meth)acrylate such as a urethane (meth)acrylate, polyester (meth)acrylate, epoxy (meth)acrylate, or polyether (meth)acrylate. From the standpoint of heat resistance, epoxy resins and cellulose ester resins are preferred. The ink layer is preferably formed by applying a urethane gravure printing ink by gravure printing. It is particularly preferred to apply the ink by gravure printing using a multicolor gravure printer. The ink may also contain colorants, inorganic fillers, organic fillers, antifoaming agents, leveling agents, antiblocking agents, waxes, pigment dispersants, antistatic agents, slip agents, plasticizers, tackifiers, etc. Any known material can be appropriately selected as long as it does not impair the properties of the ink.

[0088] Examples of pigments include inorganic pigments such as titanium dioxide, barium sulfate, calcium carbonate, silica, zinc oxide, zinc sulfide, mica, talc, and pearl; organic pigments such as phthalocyanine-based, insoluble azo-based, condensed azo-based, dioxazine-based, anthraquinone-based, quinacridone-based, perylene-based, perinone-based, thioindigo-based, and carbon black; and various other fluorescent pigments, metal powder pigments, and extender pigments. These pigments may be used alone or in combination of two or more. Dyes that are soluble or dispersible in solvents are preferred, and may be used alone or in combination of two or more. Among these, pigments are preferred from the viewpoint of durability.

[0089] Furthermore, a fourth adhesive layer can be laminated on the laminate film, forming a chemical bond between the film substrate and the target object, thereby achieving strong adhesion. In the present invention, the resin forming the adhesive layer is preferably a thermosetting resin that hardens by forming a three-dimensional network structure when heated or with a curing agent. Examples of suitable resins include alkyl monoglycidyl ether, phenyl glycidyl ether, alkylphenol monoglycidyl ether, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 1-(3-glycidoxypropyl)-1,1,3,3,3-pentamethyldisiloxane, alkyl monoglycidyl ester, and bisphenol A epoxy resins, such as AER-X8501 manufactured by Asahi Kasei, R-301 manufactured by Mitsui Chemicals, YL-980 manufactured by Japan Epoxy Resins, and N-730S manufactured by Dainippon Ink and Chemicals, Inc. Also suitable are unsaturated carboxylic acid or acrylic acid modified polyolefin resins, such as those available under the trade name Admer manufactured by Mitsui Chemicals, Inc. and Modic manufactured by Sanyo Chemical Industries, Ltd. [Example]

[0090] The laminate film of the present invention will be described in more detail below with reference to examples, but the laminate film of the present invention is not limited thereto. The methods for measuring each property and evaluating each effect in the present invention are as follows.

[0091] [Methods for measuring characteristics and evaluating effects] (1) Surface free energy of resin layer X or resin layer Y First, the laminated film was left in an atmosphere of room temperature (23°C) and relative humidity (RH) 65% for 24 hours. Then, under the same atmosphere, the contact angles of four liquids (pure water, ethylene glycol, formamide, and diiodomethane) on the resin layer X were measured at five points using a contact angle meter DM-501 (Kyowa Interface Science Co., Ltd.), and the average of these measurements was used as the contact angle for each liquid. Next, using the contact angles of the four liquids obtained, the solid's surface free energy (γ) was separated into three components: dispersion force (γSd), polar force (γSp), and hydrogen bonding force (γSh) using the geometric mean method based on the "extended Fowkes equation" proposed by Hata et al., and the surface free energy of the present invention, which is the dispersion force, polar force, hydrogen bonding force, and the sum of dispersion force and polar force, was calculated. The specific calculation method is described below. The meaning of each symbol is explained below. γSL: Surface free energy of the resin layer and the known solution listed in Table 1 γS: Surface free energy of the resin layer γL: Surface free energy of known solutions listed in Table 1 γSd: Dispersion force component of the surface free energy of the resin layer γSp: Polar component of the surface free energy of the resin layer γSh: Hydrogen bonding force component of the surface free energy of the resin layer γLd: Dispersion force component of the surface free energy of known solutions listed in Table 1 γLp: Polar component of the surface free energy of known solutions listed in Table 1 γLh: Hydrogen bonding force component of the surface free energy of known solutions listed in Table 1 Here, when γSL is the tension at the interface between the solid and the liquid, equation (1) holds. γSL=γS+γL-2(γSd·γLd) 1 / 2 -2(γSp γLp) 1 / 2 -2(γSh γLh) 1 / 2 ··· Formula (1).

[0092] Furthermore, the state when a droplet is in contact with a smooth solid surface at a contact angle (θ) is expressed by the following equation (Young's equation): γS = γSL + γL cosθ ··· Equation (2).

[0093] Combining these formulas (1) and (2), the following formula is obtained: (γSd γLd) 1 / 2 +(γSp γLp) 1 / 2 +(γSh γLh) 1 / 2 =γL(1+cosθ) / 2 ··· Equation (3).

[0094] In practice, the contact angles (θ) of four liquids, namely water, ethylene glycol, formamide, and diiodomethane, and the components of the surface tension of known liquids (γLd, γLp, γLh) listed in Table 1 were substituted into equation (3) to solve four simultaneous equations. As a result, the surface free energy of the solid (γ), the dispersion force component (γSd), the polar force component (γSp), and the hydrogen bonding force component (γSh) were calculated as the solutions to the simultaneous equations.

[0095] [Table 1]

[0096] (2) Thickness of Resin Layer X or Resin Layer Y The thickness of the resin layer X or resin layer Y on the substrate was measured by observing the cross section using a transmission electron microscope (TEM). The thickness of the resin layer was read from an image taken with the TEM at a magnification of 200,000 times. The thickness of the resin layer was measured at a total of 20 points, and the average value was taken as the thickness of the resin layer X.

[0097] (3) Initial adhesion of hard coat Arakawa Chemical Industries, Ltd.'s UV-curable resin Z7415 (solid content 20%) was applied to the surface of resin layer X or resin layer Y of the laminated film using the wire bar coating method to a thickness of approximately 1 μm, and after drying at 90°C for 1 minute, it was irradiated using an ultraviolet lamp with an irradiation intensity of 120 W / cm, at an irradiation distance (distance between the lamp and the surface coated with the water-based coating material) of 12 cm, with a conveyor speed of 2 m / min, and an integrated intensity of approximately 300 mJ / cm. 2The film was then cured by UV irradiation under the conditions of . Hereafter, this film is referred to as the hard-coated laminate film. According to JIS 5600-5-6 (established in 1999), 100 10 x 10 squares were cut at 1 mm intervals on the hard-coated surface of the hard-coated laminate film sample obtained above. Next, 18 mm of "Cellotape" (registered trademark) (manufactured by Nichiban Co., Ltd., product number: CT-18S) was firmly rubbed and pressed with a finger on the cut area so that the cuts were visible. The "Cellotape" (registered trademark) was then instantly peeled off at an angle of approximately 60° to the hard-coat layer. The number of squares where the hard-coat layer remained was then counted. The evaluation was performed five times, and the average (rounded up to the nearest whole number) was used to evaluate the initial adhesion of the hard coat according to the following criteria. S: No peeling at all (pass) A: 99-95 remaining squares (pass) B: 96-90 remaining squares (pass) C: 89 to 70 remaining squares (failed) D: Less than 70 remaining squares (failed) E: Measurement impossible because the substrate was torn during peeling (failed).

[0098] (4) Adhesion after high-temperature and moist heat treatment A hard-coated laminate film was obtained using the same method as in (3). Next, the four sides of the obtained hard-coated laminate film were fixed with a metal frame, and the sample was placed in a high-temperature, high-humidity chamber at 120°C and 95% RH for 500 hours, and the adhesion was measured and evaluated using the same method as in (3).

[0099] (5) Adhesion after heat-resistant treatment A hard-coated laminate film was obtained in the same manner as in (3). Next, the obtained hard-coated laminate film sample was placed in a hot air oven at 150°C for 500 hours, and the adhesion was measured and evaluated in the same manner as in (3).

[0100] (6) Thermal deformation Regarding the influence of the heat treatment in the step of forming the resin layer X or the resin layer Y described below, the degree of deformation of the obtained laminated film was evaluated according to the following criteria. A: No undulations or curls are observed on the film (passed) B: The film has a very slight ripple or curl (pass). C: The film is wavy or curled, but still usable (acceptable).

[0101] (7) Confirm the structure of the resin that forms the resin layer X or resin layer Y The method for confirming the structure of the resin that forms the resin layer X is pyrolysis gas chromatography mass spectrometry (GCMS). C-MS), Fourier transform infrared spectroscopy (FT-IR), proton nuclear magnetic resonance spectroscopy ( 1 H- Three types of NMR (NMR) are performed, and a comprehensive judgment can be made from all the results. Using pyrolysis GC-MS and FT-IR, the presence or absence and intensity of peaks derived from the structure of nadiimide compounds and carbodiimide compounds can be compared to evaluate the content. In addition, the structure of nadiimide compounds can be evaluated by: 1 The chemical shift position due to the position of hydrogen atoms and the proton absorption line area due to the number of hydrogen atoms were confirmed by H-NMR. The equipment and measurement conditions used for the measurement are shown below.

[0102] <Pyrolysis GC-MS> Pyrolysis furnace: PY-3030D (manufactured by Frontier Lab) Heating temperature: 600℃ GC-MS (Agilent) conditions Column: "UltraALLOY" (registered trademark)-5 5% diphenyl + 95% dimethylpolysiloxane Column temperature: 40°C (3 minutes) - 320°C (18 minutes) at a rate of 20°C / min Injection temperature: 300℃ <ft-ir> IR: Nicolet iS5 (Thermo Fisher Scientific) Sample preparation method: KBr Measurement mode: Transmittance Resolution: 8cm-1 Accumulation count: 64 times < 1 H-NMR NMR: ECA-400 (JOEL) Resonance wavelength: 399.78MHz Number of scans: 32 <Coating composition for resin layer X or resin layer Y> The following coating compositions were prepared: [Nadiimide Compound] A1: Chukyo Oil & Fats' bisallylnadiimide aqueous emulsion "Rezem" (registered trademark) IM-N160 (curing temperature 160°C) A2: Chukyo Oils and Fats' bisallylnadiimide aqueous emulsion "Rezem" (registered trademark) IM-3 (curing temperature 250°C) [Polyester resin] B1: GOO Chemical water-dispersible polyester "Pluscoat" (registered trademark) Z740 [Carbodiimide Compound] C1: Carbodiimide water-based crosslinking agent "Carbodilite" (registered trademark) V-04 manufactured by Nisshinbo Chemical [Oxazoline-containing polymer] D1: Oxazoline-containing polymer aqueous dispersion "Epocross" (registered trademark) WS-500 manufactured by Nippon Shokubai [Melamine compounds] E1: Methylated melamine water dispersion "Nicalac" (registered trademark) MW-12LF manufactured by Nippon Carbide [Surfactant] Fluorine-based surfactant "Plus Coat" (registered trademark) RY-2 manufactured by GOO Chemical Industry Co., Ltd. [Inorganic particles] F1: Silica particles "Snowtex" (registered trademark) MP-2040 manufactured by Nissan Chemical Industries, Ltd., having an average particle size of 170 nm.

[0103] Example 1 <Paint composition> First, the mass of dilution water required was calculated from the mass of each component added and the solids concentration shown in Table 1. The mass of surfactant was calculated to be 0.03 parts by mass relative to the total mass of the coating composition to be prepared, and this was added to the dilution water and mixed thoroughly. Next, 100 parts by mass of A1 as a binder resin was added to this mixture of dilution water and surfactant, followed by 10 parts by mass of C1. Furthermore, silica particles were added so that the amount was 0.1 part by mass relative to 100 parts by mass of the binder resin, and the mixture was mixed thoroughly to prepare the coating composition.

[0104] <Laminated film> PET pellets (intrinsic viscosity 0.64 dl / g) containing 2% by mass of silica particles with a primary particle size of 0.3 μm as a lubricant were thoroughly vacuum-dried, then fed into an extruder and melted at 280°C. The pellets were extruded into a sheet from a T-shaped die and wrapped around a mirror-finished casting drum at a surface temperature of 25°C using an electrostatic casting method, where they were cooled and solidified. The resulting unstretched film (Film A) was heated to 90°C and stretched 3.1 times in the longitudinal direction to produce a uniaxially stretched film (Film B). The uniaxially stretched film was then subjected to a corona discharge treatment in air, after which the above-mentioned coating composition was applied using a bar coater (wire bar #4). The coated uniaxially stretched film was then held at both widthwise ends with clips and introduced into a preheating zone. The ambient temperature in the preheating zone was set to 90-100°C, where the solvent in the coating composition was dried. The film was then continuously stretched 3.6 times in the width direction in a 100°C stretching zone and heat-treated for 20 seconds in a 230°C heat-treatment zone to form a resin layer X. It was then subjected to a 5% relaxation treatment in the width direction at the same temperature to obtain a laminated film in which the crystal orientation of the polyester film was completed. In the resulting laminated film, the PET film (polyester film) had a thickness of 38 μm, and the resin layer X had a thickness (film thickness) of 80 nm. The evaluation results are shown in Tables 2 and 3.

[0105] (Examples 2 to 11, Comparative Examples 1 to 3) A laminated film was obtained in the same manner as in Example 1, except that the formulation of the coating composition was as shown in Table 2. Other evaluation results are shown in Tables 2 and 3.

[0106] Comparative Example 4 A polyester film was obtained in the same manner as in Comparative Example 1, except that no coating was performed. Other evaluation results are shown in Tables 2 and 3.

[0107] (Examples 12 to 17) The substrate film was changed to the following commercially available film. Aromatic polyamide: Toray "Mictron" (registered trademark) #12GF10 PPS: Toray "Torelina" (registered trademark) #25-3030 LCP: Kuraray "Vecstar" (registered trademark) CTQ-25 PEEK: PEEK film manufactured by Toray Plastics Seiko PEI: SABIC Innovative Plastics Japan "Ultem" (registered trademark) Natural Ultem 1000 The surface of each film was subjected to surface treatment using a high-frequency power supply AGF-B10 manufactured by Kasuga Electric, with two round trips at an output of 1 kW. The coating composition was as shown in Table 2, and the coating composition was applied using a bar coater (wire bar #2). The coating composition was then dried in a hot air oven at 100°C for 30 seconds to remove the solvent from the coating composition. Subsequently, the four sides of the film were clamped and fixed with metal clips, and heat treatment was performed in a hot air oven at the curing temperature and degree shown in Table 2 to form a resin layer X. The thickness (film thickness) of the resin layer X was 80 nm. The evaluation results are shown in Tables 2 and 3.

[0108] (Examples 18 to 20) The coating composition had the composition shown in Table 2, and a resin layer Y was formed using the same base resin and manufacturing method as in Examples 13, 14, and 20. The thickness (film thickness) of the resin layer Y was 80 nm. The evaluation results are shown in Tables 2 and 3.

[0109] [Table 2]

[0110] [Table 3] [Industrial Applicability]

[0111] The present invention relates to an easily adhesive film that exhibits excellent adhesion even when stored for a long period of time in a high-temperature, humid, and hot atmosphere, and can be used as a film for an in-vehicle display or a film for an in-vehicle electronic component, etc. Furthermore, by using a super engineering plastic resin as the base resin, the film can be used as an insulating film, a heat-resistant film, a bonding base material, a protective film for a semiconductor element, etc.

Claims

1. A laminated film having a resin layer X or a resin layer Y on at least one surface of a substrate, which satisfies either of the following conditions 1 or 2: Condition 1: The resin layer X contains a nadimide compound and a carbodiimide compound. Condition 2: The resin of the substrate is at least one resin selected from the group consisting of aromatic polyamide, polyphenylene sulfide, liquid crystal polyester, polyether ether ketone, and polyether imide, and the resin layer Y contains a nadimide compound.

2. 2. The laminated film according to claim 1, wherein the surface free energy of the resin layer X or the resin layer Y is 35.0 mN / m or more and 55.0 mN / m or less.

3. 2. The laminate film according to claim 1, wherein the laminate film has a resin layer X on at least one surface of a substrate and satisfies the following conditions 1-2: Condition 1-2: The resin layer X contains a nadimide compound, a carbodiimide compound, and an oxazoline compound.

4. 2. The laminate film according to claim 1, wherein the laminate film has a resin layer X on at least one surface of a substrate and satisfies the following conditions 1 to 3: Condition 1-3: The resin layer X contains a nadimide compound and a carbodiimide compound. Furthermore, the resin of the substrate is at least one resin selected from the group consisting of aromatic polyamide, polyphenylene sulfide, liquid crystal polyester, polyether ether ketone, and polyether imide.

5. A laminate comprising the laminate film according to claim 1 , and a functional layer on the surface of said resin layer X or said resin layer Y.

6. The laminate according to claim 5, wherein the functional layer is any one of a hard coat layer, an adhesive layer, an ink layer, and an adhesive layer.

7. 2. The laminated film according to claim 1, which is used as an insulating film, a heat-resistant film, a bonding substrate, a protective film for semiconductor elements, a heat-resistant tape, a circuit member, or a battery member.

8. The laminated film according to claim 1, which is used as a film for an in-vehicle display or a film for an in-vehicle electronic part.

9. A gasket comprising the laminated film according to claim 1 and an adhesive layer.

10. A fuel cell comprising the gasket of claim 9.

11. A method for producing a laminated film having a resin layer X or a resin layer Y on at least one surface of a substrate, the method satisfying either of the following conditions 1 or 2, and comprising a step of forming the resin layer X or the resin layer Y by thermally curing a coating composition at 180°C or higher: Condition 1: The resin layer X contains a nadimide compound and a carbodiimide compound. Condition 2: The resin of the substrate is at least one selected from the group consisting of aromatic polyamide, polyphenylene sulfide, liquid crystal polyester, polyether ether ketone, and polyetherimide, and the resin layer Y contains a nadimide compound.

12. A method for producing a laminate, comprising the step of forming a functional layer on the surface of the laminate film obtained by the method according to claim 11 that faces the resin layer X or the resin layer Y.

13. The method for producing a laminate according to claim 12, wherein the functional layer is any one of a hard coat layer, an adhesive layer, an ink layer, and an adhesive layer.

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