laminate

Abstract

This laminate includes a base material layer, a first adhesive layer, a metal foil layer, a second adhesive layer, and a sealant layer that are sequentially laminated. The second adhesive layer includes an acid-modified polyolefin-based adhesive. The elastic modulus obtained by force curve measurement of the second adhesive layer in a cross section of the laminate in an 80°C environment using a scanning probe microscope is 3 MPa-100 MPa inclusive.

Description

Laminate

[0001] The present disclosure relates to a laminate.

[0002] Known examples of storage battery devices include secondary batteries such as lithium-ion batteries, nickel-metal hydride batteries, and lead-acid batteries, as well as electrochemical capacitors such as electric double-layer capacitors. Due to the miniaturization of portable devices and limitations on installation space, there is a demand for further miniaturization of storage battery devices, and lithium-ion batteries with high energy density have attracted attention. Multilayer films (laminates) that are lightweight, have high heat dissipation properties, and can be produced at low cost have begun to be used as exterior materials for lithium-ion batteries.

[0003] Lithium-ion batteries using the above multilayer film as an exterior material are called laminated lithium-ion batteries. The exterior material covers the battery contents (positive electrode, separator, negative electrode, electrolyte, etc.), preventing moisture from penetrating into the battery contents. An example of a laminated lithium-ion battery is the laminate disclosed in Patent Document 1 below. The insulating layer contained in the laminate is formed from a resin composition containing a modified polyolefin resin modified with an unsaturated carboxylic acid or its acid anhydride and having a modification degree of 2.5 to 18.0 mass %, and a curing agent for curing the modified polyolefin resin. The hardness of the insulating layer, measured using a nanoindenter by pressing an indenter 5 μm into the insulating layer from a cross section in the stacking direction of the laminate, is in the range of 15 MPa to 240 MPa.

[0004] Patent No. 5821900

[0005] Research and development is currently being conducted on storage battery devices known as all-solid-state batteries as the next generation of lithium-ion batteries. All-solid-state batteries use a solid electrolyte instead of an organic electrolyte solution as the electrolyte. Lithium-ion batteries containing an organic electrolyte solution cannot be used at temperatures higher than the boiling point of the electrolyte solution (approximately 80°C). In contrast, all-solid-state batteries (i.e., lithium-ion batteries without an organic electrolyte solution) can be used at temperatures exceeding 100°C. Therefore, by operating an all-solid-state battery in a high-temperature environment (e.g., between 80°C and 150°C), the conductivity of lithium ions can be increased.

[0006] However, if the above-mentioned conventional multilayer film is simply used as the exterior material for an all-solid-state battery, interlayer adhesion in a high-temperature environment is not ensured. In other words, the conventionally used multilayer film is not suitable for the operating environment of an all-solid-state battery. Therefore, from the perspective of interlayer adhesion in a high-temperature environment, it is considered to use urethane adhesives or epoxy adhesives, which are generally considered to have high heat resistance, rather than polyolefin-based adhesives. However, the moisture barrier properties of urethane adhesives and epoxy adhesives are insufficient. Therefore, if an adhesive considered to have high heat resistance is simply used, there is a risk that moisture from the atmosphere will penetrate into the all-solid-state battery through the exterior material. In this case, sulfides in the all-solid-state battery may react with moisture, generating hydrogen sulfide.

[0007] An object of one aspect of the present disclosure is to provide a laminate that exhibits good moisture barrier properties and can be used in high-temperature environments.

[0008] A laminate according to one aspect of the present disclosure comprises a base material layer, a first adhesive layer, a metal foil layer, a second adhesive layer, and a sealant layer, which are laminated in this order, and the second adhesive layer contains an acid-modified polyolefin adhesive, and the elastic modulus obtained by force curve measurement of the second adhesive layer in a cross section of the laminate using a scanning probe microscope in an environment of 80°C is 3 MPa or more and 100 MPa or less.

[0009] In this laminate, the second adhesive layer contains an acid-modified polyolefin adhesive with good moisture barrier properties, and the modulus of elasticity obtained by force curve measurement of the second adhesive layer at a cross section of the laminate using a scanning probe microscope at 80°C is 3 MPa or more and 100 MPa or less. By using a second adhesive layer that satisfies the above modulus of elasticity in a high-temperature environment, the second adhesive layer can exhibit good adhesion in a high-temperature environment, even when it contains an acid-modified polyolefin adhesive. Therefore, it is possible to provide a laminate that exhibits good moisture barrier properties and can be used in a high-temperature environment.

[0010] When the second elastic modulus is obtained by measuring the force curve of the second adhesive layer at a cross section of the laminate using a scanning probe microscope in an environment of 25°C, the ratio of the elastic modulus divided by the second elastic modulus may be 0.5% or more and 10% or less. Furthermore, the ratio of the elastic modulus divided by the second elastic modulus may be 0.5% or more and 5% or less. In this case, even when an acid-modified polyolefin adhesive is contained, the second adhesive layer can exhibit better adhesiveness in a high-temperature environment.

[0011] A laminate according to another aspect of the present disclosure includes a base material layer, a first adhesive layer, a metal foil layer, a second adhesive layer, and a sealant layer, which are laminated in this order, and the second adhesive layer contains an acid-modified polyolefin-based adhesive. When a maximum adhesive force obtained by force curve measurement of the second adhesive layer at a cross section of the laminate using a scanning probe microscope at 25°C is defined as a first maximum adhesive force, and when a maximum adhesive force obtained by force curve measurement of the second adhesive layer at a cross section of the laminate at 80°C is defined as a second maximum adhesive force, the ratio of the second maximum adhesive force divided by the first maximum adhesive force is 70% or more and 300% or less.

[0012] In this laminate, the second adhesive layer contains an acid-modified polyolefin adhesive with good moisture barrier properties, and the ratio of the second maximum adhesive strength in the second adhesive layer divided by the first maximum adhesive strength is 70% or more and 300% or less. By using a second adhesive layer that satisfies this ratio, the second adhesive layer can exhibit good adhesion in high-temperature environments, even when it contains an acid-modified polyolefin adhesive. Therefore, it is possible to provide a laminate that exhibits good moisture barrier properties and can be used in high-temperature environments.

[0013] The ratio of the second maximum adhesive force divided by the first maximum adhesive force may be 73% or more and 273% or less. Also, the ratio of the second maximum adhesive force divided by the first maximum adhesive force may be 125% or more and 273% or less. In this case, even when an acid-modified polyolefin adhesive is contained, the second adhesive layer can exhibit better adhesiveness in a high-temperature environment.

[0014] The acid-modified polyolefin adhesive may be a reaction product of an acid-modified polyolefin and a polyfunctional isocyanate. The reaction product has a crosslinked structure formed by the reaction of a polar group contained in the acid-modified polyolefin with a polyfunctional isocyanate compound. This increases the glass transition temperature of the reaction product contained in the polyolefin adhesive, making it difficult for the molecular chains in the polymer compound to disentangle. This makes it difficult for the gaps between the molecules in the polymer compound to widen, further improving the moisture barrier properties of the second adhesive layer. In addition, the inclusion of the crosslinked structure improves the heat resistance of the second adhesive layer.

[0015] The polyfunctional isocyanate may include an isocyanurate-type polyfunctional isocyanate compound, in which case the moisture barrier property and heat resistance of the second adhesive layer are further improved.

[0016] The laminate may further include a corrosion prevention treatment layer located between the metal foil layer and the second adhesive layer and provided on the surface of the metal foil layer, the corrosion prevention treatment layer being in contact with the second adhesive layer, which effectively prevents peeling of the metal foil layer from the second adhesive layer in a high-temperature environment.

[0017] The sealant layer may be in contact with the second adhesive layer and may contain a polyolefin resin as the main component, which effectively prevents the sealant layer from peeling off from the second adhesive layer in a high-temperature environment.

[0018] The main component of the sealant layer may be a polyester resin, in which case the heat resistance of the sealant layer can be improved.

[0019] The laminate may be an exterior material for a storage battery device or an exterior material for an all-solid-state battery.

[0020] According to one aspect of the present disclosure, there is provided a laminate that exhibits good moisture barrier properties and can be used in high-temperature environments.

[0021] 1 is a schematic cross-sectional view of a stack according to an embodiment of the present invention, and FIG. 2 is a perspective view of a storage battery device according to an embodiment of the present invention.

[0022] Hereinafter, an embodiment of the present disclosure will be described in detail with reference to the drawings. In the drawings, the same or corresponding parts are designated by the same reference numerals, and duplicate explanations will be omitted. Furthermore, the dimensional ratios of the drawings are not limited to those shown in the drawings.

[0023] [Storage Battery Device Exterior Material] Fig. 1 is a schematic cross-sectional view of a laminate according to one embodiment. As shown in Fig. 1, the laminate 10 is a multilayer film used as an exterior material (exterior material for storage battery devices) for storage battery devices such as secondary batteries (e.g., lithium-ion batteries, nickel-metal hydride batteries, lead-acid batteries), and electrochemical capacitors (e.g., electric double-layer capacitors). The laminate 10 includes a base layer 11, a first adhesive layer 12, a metal foil layer 13 provided with corrosion-resistant treatment layers 14a and 14b, a second adhesive layer 15, and a sealant layer 16, which are stacked in this order. Here, the corrosion-resistant treatment layer 14a is located on the surface 13a of the metal foil layer 13 facing the first adhesive layer 12, and the corrosion-resistant treatment layer 14b is located on the surface 13b of the metal foil layer 13 facing the second adhesive layer 15. The thickness of the metal foil layer 13 is significantly greater than the thicknesses of the corrosion-resistant treatment layers 14a and 14b. In the laminate 10, the base layer 11 is the outermost layer, and the sealant layer 16 is the innermost layer. Each layer will be described below.

[0024] <Substrate Layer> The substrate layer 11 is a sheet-like member that functions as the outermost layer of the storage battery device when the laminate 10 is used as an exterior material. The substrate layer 11 provides heat resistance in the sealing process when manufacturing the storage battery device and plays a role in suppressing the occurrence of pinholes that may occur during molding, distribution, etc. In particular, in the case of an exterior material for a large-scale storage battery device, the substrate layer 11 may also be provided with scratch resistance, chemical resistance, insulating properties, etc.

[0025] The substrate layer 11 may have a peak melting temperature higher than the peak melting temperature of the sealant layer 16. In this case, deformation of the appearance of the laminate 10 due to melting of the substrate layer 11 during heat sealing of the laminate 10 can be suppressed. When the sealant layer 16 has a multilayer structure, the peak melting temperature of the sealant layer 16 means the peak melting temperature of the layer with the highest peak melting temperature. The peak melting temperature of the substrate layer 11 is, for example, 290°C or higher and 350°C or lower. The peak melting temperature means a value determined in accordance with the method described in JIS K7121-1987. The peak melting temperature T of the substrate layer 11 １１ and the melting peak temperature T of the sealant layer 16 １６ The temperature difference (T １１ -T １６ is, for example, 20° C. or more. When the temperature difference is 20° C. or more, deterioration of the appearance of the laminate 10 due to heat sealing can be effectively suppressed.

[0026] The base layer 11 is a layer formed of, for example, an insulating resin, such as polyester resin, polyamide resin, polyimide resin, polyamideimide resin, polyetherketone resin, polyphenylene sulfide resin, polyetherimide resin, polysulfone resin, fluororesin, phenol resin, melamine resin, urethane resin, allyl resin, silicone resin, epoxy resin, furan resin, or acetyl cellulose resin.

[0027] Among these resins, at least one of polyester resin and polyamide resin may be used as the resin for the base layer 11 from the viewpoint of moldability. Examples of polyester resins include polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate. Examples of polyamide resins include nylon 6, nylon 6,6, a copolymer of nylon 6 and nylon 6,6, nylon 9T, nylon 10, polymetaxylylene adipamide (MXD6), nylon 11, and nylon 12. The base layer 11 may contain additives depending on the desired performance.

[0028] The substrate layer 11 may be in the form of a stretched or unstretched film, or in the form of a coating film. The substrate layer 11 may be a single layer or a multilayer. When the substrate layer 11 is a multilayer, the layers included in the substrate layer 11 may be formed from different resins or from the same resin. When the substrate layer 11 is in the form of a film, the substrate layer 11 may be formed by coextrusion or may be laminated via an adhesive. When the substrate layer 11 is a coating film, the coating film is obtained, for example, by coating a coating film-forming composition multiple times. The substrate layer 11 may have a multilayer structure combining a film and a coating film.

[0029] When the above-mentioned resin is used in the form of a film, the base layer 11 may be a biaxially stretched film. In this case, the formability of the laminate 10 is improved. Examples of the stretching method for the biaxially stretched film include sequential biaxial stretching, tubular biaxial stretching, and simultaneous biaxial stretching. From the viewpoint of deep draw formability, the biaxially stretched film may be a film stretched by tubular biaxial stretching.

[0030] The thickness of the substrate layer 11 is 10 μm or more and 60 μm or less. The thickness of the substrate layer 11 may be 15 μm or more, 20 μm or more, 25 μm or more, 50 μm or less, 40 μm or less, or 35 μm or less. By having the thickness of the substrate layer 11 within the above range, the thermal conductivity of the substrate layer 11 can be set within a good range. The substrate layer 11 may contain, for example, various additives (e.g., flame retardants, slip agents, antiblocking agents, antioxidants, light stabilizers, tackifiers, etc.).

[0031] <First Adhesive Layer> The first adhesive layer 12 is a layer that bonds the metal foil layer 13, on which the corrosion prevention treatment layer 14a is provided, to the base layer 11. The first adhesive layer 12 has the adhesive strength necessary to firmly bond the base layer 11 and the metal foil layer 13. The first adhesive layer 12 also has conformability to prevent the metal foil layer 13 from being broken by the base layer 11. Conformability refers to the property of the first adhesive layer 12 remaining on the member without peeling off, even if the member is deformed due to expansion and contraction, etc.

[0032] Examples of adhesive components forming the first adhesive layer 12 include urethane-based compounds, urea-based compounds, epoxy-based compounds, and silicon-based compounds. These compounds may be used alone or in combination of two or more. Urethane-based compounds are obtained by reacting a polyol resin with a multifunctional isocyanate compound. Urea-based compounds are obtained by reacting an amine-based compound or amine derivative with a multifunctional isocyanate compound.

[0033] Examples of polyol resins include polyester polyols, polyether polyols, polycarbonate diols, and polyacrylic polyols. Examples of polyester polyols include polyester polyols obtained by reacting one or more dicarboxylic acids with a diol. Examples of polyether polyols include those produced by addition polymerization of ethylene oxide or propylene oxide with propylene glycol, glycerin, pentaerythritol, etc. Examples of polycarbonate polyols include polycarbonate polyols obtained by reacting a diol with a carbonate diester such as diphenyl carbonate. Examples of polyacrylic polyols include copolymers obtained by copolymerizing at least a hydroxyl group-containing acrylic monomer with (meth)acrylic acid. In this case, structural units derived from (meth)acrylic acid may be included as the main component. Examples of hydroxyl group-containing acrylic monomers include 2-hydroxyethyl (meth)acrylate and 2-hydroxypropyl (meth)acrylate.

[0034] The polyfunctional isocyanate compound contains multiple isocyanate groups and serves to crosslink the amine resin or polyol. The polyfunctional isocyanate compound may be used alone or in combination of two or more. Examples of the polyfunctional isocyanate compound include an aliphatic polyfunctional isocyanate compound, an alicyclic polyfunctional isocyanate compound, and a polyfunctional isocyanate compound having an aromatic ring.

[0035] Examples of aliphatic polyfunctional isocyanate compounds include hexamethylene diisocyanate (HDI) and xylylene diisocyanate (XDI). Examples of alicyclic polyfunctional isocyanate compounds include isophorone diisocyanate (IPDI). Examples of polyfunctional isocyanate compounds having an aromatic ring include tolylene diisocyanate (TDI) and diphenylmethane diisocyanate (MDI). Multimers (e.g., trimers) of these compounds can also be used as polyfunctional isocyanate compounds. Specifically, adducts, biurets, isocyanurates, and the like can be used.

[0036] From the viewpoint of improving pot life, the isocyanate group of the polyfunctional isocyanate compound may be bonded to a blocking agent. Examples of blocking agents include methyl ethyl ketoxime (MEKO). The temperature at which the blocking agent is detached from the isocyanate group of the polyfunctional isocyanate compound may be 50°C or higher. From the viewpoint of improving pot life, the temperature may be 60°C or higher. The temperature at which the blocking agent is detached from the isocyanate group of the polyfunctional isocyanate compound may be 140°C or lower. From the viewpoint of molding curl resistance of the laminate 10, the temperature may be 120°C or lower.

[0037] A catalyst for lowering the dissociation temperature of the blocking agent may be used to lower the dissociation temperature, such as tertiary amines such as triethylenediamine and N-methylmorpholine, and metal organic acid salts such as dibutyltin dilaurate.

[0038] An amine compound is a compound having an amino group in the molecule. ２ , -NHR, -NR ２ where R represents an alkyl group and / or an aryl group. The amine derivative is a compound derived from an amine compound and does not have an amino group in the molecule.

[0039] Amine compounds and amine derivatives may be latent curing agents or latent curing agents. Latent curing agents are curing agents that are activated by an external stimulus to generate reactive groups that can react with isocyanate groups. When amine compounds and amine derivatives are latent curing agents, the pot life tends to be improved. Examples of external stimuli include heat and moisture. Examples of latent curing agents include imidazole curing agents, imine curing agents, amine imide curing agents, dicyandiamide curing agents, aromatic polyamine curing agents, aliphatic polyamine curing agents, polyamidoamine curing agents, tertiary amine salt curing agents, and oxazolidine curing agents. Among these, examples of latent curing agents that are activated by heat include imidazole curing agents, dicyandiamide curing agents, polyamine curing agents, and amine imide curing agents. Examples of latent curing agents that are activated by moisture include imine curing agents and oxazolidine curing agents. From the viewpoint of improving the pot life, the latent curing agent may be one that is activated by moisture.

[0040] From the viewpoint of inhibiting corrosion of the metal foil layer 13 by hydrogen sulfide, the first adhesive layer 12 may contain a hydrogen sulfide treatment substance. The hydrogen sulfide treatment substance is a substance that chemically reacts with hydrogen sulfide (hydrogen sulfide reactive substance), such as zinc oxide or potassium permanganate. In these cases, the hydrogen sulfide treatment substance also functions as a thermally conductive filler, thereby improving the heat dissipation properties of the laminate 10. From the viewpoint of inhibiting corrosion of the metal foil layer 13 by hydrogen sulfide, the content of the hydrogen sulfide treatment substance in the first adhesive layer 12 is, for example, 1% by mass or more and 50% by mass or less with respect to the total amount of the first adhesive layer 12.

[0041] The thickness of the first adhesive layer 12 is not particularly limited, but is, for example, 1 μm or more and 10 μm or less, or 2 μm or more and 7 μm or less, from the viewpoint of obtaining the desired adhesive strength, thermal conductivity, conformability, processability, etc.

[0042] The first adhesive layer 12 can be obtained, for example, by applying a composition containing the above-described components. The application method can be a known method, such as gravure direct, gravure reverse (direct, kiss), and microgravure.

[0043] The composition may contain a solvent. Examples of the solvent include ethyl acetate, toluene, methyl ethyl ketone, methyl isobutyl ketone, and alcohols. The solvent may be used alone or in combination of two or more.

[0044] <Metal Foil Layer> The metal foil layer 13 is a layer having water vapor barrier properties that prevent moisture from penetrating into the interior of the storage battery device. The metal foil layer 13 may have extensibility for deep drawing. As the metal foil layer 13, various metal foils such as aluminum, stainless steel, copper, etc. can be used. These can be used alone or in combination of two or more. The metal foil layer 13 may be aluminum foil in terms of mass (specific gravity), moisture resistance, processability, and cost.

[0045] When the metal foil layer 13 is an aluminum foil, the metal foil layer 13 may be a soft aluminum foil that has been annealed, since this can provide the desired extensibility during molding. To further improve pinhole resistance and extensibility during molding, the metal foil layer 13 may be an aluminum foil containing iron. The iron content in the aluminum foil may be 0.1% by mass or more to 9.0% by mass or less, or 0.5% by mass or more to 2.0% by mass or less, based on 100% by mass of the aluminum foil (for example, aluminum foil made of 8021 material or 8079 material according to the JIS standard). By having an iron content of 0.1% by mass or more, a laminate 10 with better pinhole resistance and extensibility can be obtained. By having an iron content of 9.0% by mass or less, a laminate 10 with better flexibility can be obtained. Untreated aluminum foil may be used as the aluminum foil, but aluminum foil that has been degreased may also be used to provide corrosion resistance. When the aluminum foil is subjected to a degreasing treatment, the degreasing treatment may be performed on only one side of the aluminum foil, or on both sides. As the degreasing treatment, for example, a wet type degreasing treatment or a dry type degreasing treatment can be used, but from the viewpoint of simplifying the manufacturing process, a dry type degreasing treatment may also be performed.

[0046] An example of the dry-type degreasing treatment is a method in which the degreasing treatment is performed by extending the treatment time during the annealing treatment of the metal foil. Sufficient electrolyte resistance can be obtained even with the degreasing treatment performed simultaneously with the annealing treatment performed to soften the metal foil.

[0047] The dry-type degreasing treatment may be a treatment other than the annealing treatment, such as flame treatment or corona treatment. Furthermore, the dry-type degreasing treatment may be, for example, a degreasing treatment in which contaminants are oxidatively decomposed and removed by active oxygen generated when a metal foil is irradiated with ultraviolet light of a specific wavelength.

[0048] The wet-type degreasing treatment may be, for example, an acid degreasing treatment or an alkaline degreasing treatment. The acid used in the acid degreasing treatment may be, for example, an inorganic acid such as sulfuric acid, nitric acid, hydrochloric acid, or hydrofluoric acid. These acids may be used alone or in combination. The alkali used in the alkaline degreasing treatment may be, for example, sodium hydroxide, which has a high etching effect. The alkaline degreasing treatment may also be performed using a weak alkaline material or a material containing a surfactant or the like. The wet-type degreasing treatment described above may be performed by, for example, a dipping method or a spray method.

[0049] The thickness of the metal foil layer 13 is not particularly limited, but may be 9 μm or more and 200 μm or less, 15 μm or more and 100 μm or less, or 40 μm or more and 80 μm or less, from the viewpoints of barrier properties, pinhole resistance, processability, etc. When the thickness of the metal foil layer 13 is 9 μm or more, the metal foil layer 13 is less likely to break even when stress is applied during molding. When the thickness of the metal foil layer 13 is 200 μm or less, the increase in mass of the laminate 10 can be reduced. From the viewpoint of the thermal diffusivity of the laminate 10, the ratio of the thickness of the metal foil layer 13 to the thickness of the laminate 10 may be 15% or more, 20% or more, 23% or more, 26% or more, or 30% or more. Furthermore, from the viewpoint of the insulating properties of the laminate 10, the ratio of the thickness of the metal foil layer 13 to the thickness of the laminate 10 may be 50% or less, 45% or less, 43% or less, or 40% or less. In one embodiment, the ratio of the thickness of the metal foil layer 13 to the thickness of the laminate 10 may be 15% or more and 50% or less, 23% or more and 45% or less, or 26% or more and 45% or less.

[0050] <Corrosion prevention treatment layers> The corrosion prevention treatment layers 14a and 14b are layers provided to prevent corrosion of the metal foil layer 13. The corrosion prevention treatment layer 14a serves to increase the adhesion between the metal foil layer 13 and the first adhesive layer 12. Therefore, the corrosion prevention treatment layer 14a comes into contact with the first adhesive layer 12. The corrosion prevention treatment layer 14b serves to increase the adhesion between the metal foil layer 13 and the second adhesive layer 15. Therefore, the corrosion prevention treatment layer 14b comes into contact with the second adhesive layer 15. The corrosion prevention treatment layers 14a and 14b may be layers of the same configuration or layers of different configurations.

[0051] The corrosion prevention treatment layers 14a, 14b can be formed, for example, by carrying out a degreasing treatment, a hydrothermal treatment, an anodizing treatment, a chemical conversion treatment, a coating-type corrosion prevention treatment in which a coating agent having corrosion prevention properties is applied to the layer that serves as the base material of the corrosion prevention treatment layers 14a, 14b, or a corrosion prevention treatment that combines these treatments.

[0052] Among the above-mentioned treatments, degreasing, hydrothermal modification, and anodizing, particularly hydrothermal modification and anodizing, are treatments in which the surface of the metal foil (aluminum foil) is dissolved by a treatment agent to form a metal compound (aluminum compound (boehmite, alumite)) that has excellent corrosion resistance. For this reason, such treatments are sometimes included in the definition of chemical conversion treatment, since they obtain a structure in which a co-continuous structure is formed from the metal foil layer 13 to the corrosion prevention treatment layers 14a, 14b.

[0053] Examples of degreasing treatments include acid degreasing and alkaline degreasing. Acid degreasing methods include a method using inorganic acids such as sulfuric acid, nitric acid, hydrochloric acid, and hydrofluoric acid, either singly or in combination. For acid degreasing, an acid degreasing agent obtained by dissolving a fluorine-containing compound such as ammonium hydrogen difluoride in the inorganic acid can be used. This not only provides a degreasing effect for the metal foil layer 13, but also allows the formation of a fluoride of the passive metal, which is effective in terms of hydrofluoric acid resistance. Examples of alkaline degreasing methods include a method using sodium hydroxide or the like.

[0054] The hydrothermal modification treatment may be, for example, a boehmite treatment obtained by immersing the metal foil layer 13 in boiling water containing triethanolamine. The anodizing treatment may be, for example, an anodizing treatment. The chemical conversion treatment may be, for example, a chromate treatment, a zirconium treatment, a titanium treatment, a vanadium treatment, a molybdenum treatment, a calcium phosphate treatment, a strontium hydroxide treatment, a cerium treatment, a ruthenium treatment, or a combination of two or more of these. The degreasing treatment described above may be performed before these hydrothermal modification treatments, anodizing treatments, and chemical conversion treatments.

[0055] The chemical conversion treatment is not limited to a wet method, and may be, for example, a method in which a treatment agent used in the treatment is mixed with a resin component and applied. From the viewpoint of waste liquid treatment, an example of the corrosion prevention treatment is a paint-type chromate treatment.

[0056] Examples of coating agents used in coating-type corrosion prevention treatments include coating agents containing at least one selected from the group consisting of rare earth element oxide sols, anionic polymers, and cationic polymers. In this case, a coating agent containing a rare earth element oxide sol may be used.

[0057] The mass per unit area of ​​the corrosion prevention treatment layers 14a and 14b is 0.005 g / m ２ 0.200g / m or more ２ or less than 0.010 g / m ２ 0.100g / m or more ２ The mass per unit area may be 0.005 g / m or less. ２ If the mass per unit area is 0.200 g / m or more, the metal foil layer 13 can be provided with a good corrosion prevention function. ２ The corrosion prevention function saturates even if the thickness exceeds this value. Note that the above information is given in terms of mass per unit area, but if the specific gravity is known, it is possible to convert this into thickness.

[0058] From the viewpoint of corrosion prevention function and anchor function, the thickness of the corrosion prevention treatment layers 14a, 14b may be, for example, 10 nm or more and 5 μm or less, or 20 nm or more and 500 nm or less.

[0059] <Second Adhesive Layer> The second adhesive layer 15 is a layer that bonds the metal foil layer 13, on which the corrosion prevention treatment layer 14b is provided, to the sealant layer 16. The second adhesive layer 15 is in contact with the sealant layer 16. The second adhesive layer 15 contains at least an acid-modified polyolefin-based adhesive as an adhesive. In one example, the acid-modified polyolefin-based adhesive contains a reaction product (hereinafter also referred to as "reactant A") between an acid-modified polyolefin and a multifunctional isocyanate compound as a curing agent. In this case, the adhesive strength of the second adhesive layer 15 can be improved in addition to the formation of a crosslinked structure. The components for obtaining reactant A may be only an acid-modified polyolefin and a multifunctional isocyanate compound, or may contain other components in addition to the acid-modified polyolefin and the multifunctional isocyanate compound. Alternatively, the second adhesive layer 15 may contain other components in addition to reactant A. Examples of other components include carbodiimide compounds, epoxy resins, acrylic resins, silicone resins, silane coupling agents, silica fillers, aluminum oxide, zinc oxide, latent curing agents, and antioxidants.

[0060] The acid-modified polyolefin contains, for example, polar groups such as hydroxy groups, carboxylic groups, etc. From the viewpoint of reactivity, the hydroxyl value of the acid-modified polyolefin may be 5 KOH mg / g or more and 120 KOH mg / g or less, 10 KOH mg / g or more and 80 KOH mg / g or less, or 20 KOH mg / g or more and 60 KOH mg / g or less.

[0061] The acid-modified polyolefin may be a polyolefin graft-modified with an unsaturated carboxylic acid derivative derived from an unsaturated carboxylic acid, an unsaturated sulfonic acid, an acid anhydride of an unsaturated carboxylic acid, an ester of an unsaturated carboxylic acid, or the like. In this case, the degree of acid modification in the acid-modified polyolefin may be 2% by mass or less, 1.5% by mass or less, or 1% by mass or less. Examples of acid-modified polyolefins include maleic anhydride-modified polyolefins obtained by reacting maleic anhydride with a polyolefin. Examples of maleic anhydride-modified polyolefins include maleic anhydride-modified polypropylene and maleic anhydride-modified polyethylene.

[0062] Examples of polyfunctional isocyanate compounds include diisocyanates such as tolylene diisocyanate, xylylene diisocyanate or its hydrogenated derivatives, hexamethylene diisocyanate, 4,4'-diphenylmethane diisocyanate or its hydrogenated derivatives, and isophorone diisocyanate; or polyisocyanates such as adducts obtained by reacting these isocyanates with polyhydric alcohols such as trimethylolpropane, biuret derivatives obtained by reacting these isocyanates with water, or trimer isocyanurates (isocyanurate-type polyfunctional isocyanate compounds); or blocked polyisocyanates obtained by blocking these polyisocyanates with alcohols, lactams, oximes, or the like. The polyfunctional isocyanate compound may include an isocyanurate (isocyanurate-type polyfunctional isocyanate compound). In this case, the second adhesive layer 15 can have excellent adhesion and heat resistance.

[0063] From the viewpoint of reactivity, the amount of the polyfunctional isocyanate compound blended when reacting at least the acid-modified polyolefin with the polyfunctional isocyanate compound may be 0.5 parts by mass or more and 40 parts by mass or less, 3 parts by mass or more and 30 parts by mass or less, or 5 parts by mass or more and 20 parts by mass or less, relative to 100 parts by mass of the acid-modified polyolefin.

[0064] The amount of the acid-modified polyolefin may be 60% by mass or more, 70% by mass or more, 80% by mass or more, or 90% by mass or more based on the total amount of the components for obtaining the reaction product A.

[0065] The second adhesive layer 15 may contain a hydrogen sulfide treatment substance similar to the first adhesive layer. The type and content of the hydrogen sulfide treatment substance may be similar to those of the first adhesive layer.

[0066] The thickness of the second adhesive layer 15 is not particularly limited, but from the viewpoint of obtaining the desired adhesive strength, thermal conductivity, processability, etc., it is, for example, 0.2 μm or more and 30 μm or less, 1 μm or more and 20 μm or less, or 2 μm or more and 15 μm or less.

[0067] The second adhesive layer 15 is obtained in the same manner as the first adhesive layer 12 .

[0068] <Elastic Modulus of Second Adhesive Layer> In one example, the elastic modulus of the second adhesive layer 15 obtained in an 80°C environment (80°C elastic modulus) is, for example, 3 MPa or more and 100 MPa or less. In this case, the second adhesive layer 15 can exhibit good adhesion (sealing strength) even in a high-temperature environment (e.g., 80°C or more and 150°C or less). In one example, when the 80°C elastic modulus of the second adhesive layer 15 is within the above range, the second adhesive layer 15 exhibits a sealing strength of 10 N / cm or more at 150°C. The sealing strength of the second adhesive layer 15 at 150°C may be 30 N / cm or more, or may be 40 N / cm or more. The sealing strength of the second adhesive layer 15 corresponds to the peel strength between the sealant layer 16 and the metal foil layer 13 (corrosion prevention treatment layer 14b) via the second adhesive layer 15, and can be obtained, for example, by the method described in the following examples.

[0069] The 80°C elastic modulus of the second adhesive layer 15 may be 3 MPa or more and 40 MPa or less, 3 MPa or more and 25 MPa or less, 3 MPa or more and 15 MPa or less, 10 MPa or more and 100 MPa or less, 10 MPa or more and 40 MPa or less, or 10 MPa or more and 25 MPa or less. From the viewpoint of preventing peeling within the second adhesive layer 15, the 80°C elastic modulus of the second adhesive layer 15 may be 40 MPa or less, 25 MPa or less, or 15 MPa or less. From the viewpoint of preventing interfacial peeling between the second adhesive layer 15 and the sealant layer 16 and between the second adhesive layer 15 and the corrosion prevention treatment layer 14b, the 80°C elastic modulus of the second adhesive layer 15 may be 10 MPa or less and 30 MPa or more, or 5 MPa or less and 25 MPa or more.

[0070] The modulus of elasticity of the second adhesive layer 15 in a 25°C environment (25°C modulus of elasticity or second modulus of elasticity) is not particularly limited. For example, the ratio of the 80°C modulus of elasticity of the second adhesive layer 15 divided by the 25°C modulus of elasticity is 0.5% or more and 10% or less. In this case, the second adhesive layer 15 can exhibit good adhesiveness even in a high-temperature environment. Furthermore, by using this ratio, the high-heat adaptability of the second adhesive layer 15 can be easily determined. The ratio may be 0.5% or more and 8% or less, 0.5% or more and 5% or less, 0.5% or more and 3% or less, 0.8% or more and 10% or less, 4% or more and 10% or less, or 4% or more and 8% or less. From the viewpoint of preventing peeling within the second adhesive layer 15, the ratio may be 8% or less, 5% or less, or 3% or less. From the viewpoint of preventing interfacial peeling between the second adhesive layer 15 and the sealant layer 16, and preventing interfacial peeling between the second adhesive layer 15 and the corrosion prevention treatment layer 14b, the above ratio may be 4% or less and 8% or more, or 1% or less and 6% or more.

[0071] In one example, the 80°C elastic modulus of the second adhesive layer 15 and the 25°C elastic modulus of the second adhesive layer 15 are each obtained by measuring the elastic modulus of a cross section of the laminate 10. The elastic modulus of the cross section is obtained, for example, by measurement using a scanning probe microscope (SPM). In this case, each elastic modulus of the second adhesive layer 15 represents, for example, an elastic modulus calculated from a force curve measured using a scanning probe microscope (SPM). Each elastic modulus of the second adhesive layer 15 is obtained, for example, by the method described in the following examples.

[0072] The modulus of elasticity of the adhesive layer can be controlled, for example, by the structure, molecular weight, etc. of the components contained in the adhesive. In one example, the more acid-modified groups contained in the adhesive layer, the higher the modulus of elasticity of the adhesive layer in a high-temperature environment (i.e., the adhesive layer tends to become harder). Furthermore, when the components contained in the adhesive layer are the same, the higher the molecular weight of the component, the higher the modulus of elasticity of the adhesive layer in a high-temperature environment. The modulus of elasticity of the adhesive layer may be controllable by the type of curing agent, the amount of curing agent, the aging time, etc.

[0073] <Sealant Layer 16> The sealant layer 16 is a layer that provides heat-sealing properties to the laminate 10 and is disposed on the inner side during assembly of the storage battery device and is heat-sealed (thermally fused). The main component of the sealant layer 16 is, for example, an acrylic resin, a polyolefin resin, or a polyester resin. From the viewpoint of heat resistance, the main component of the sealant layer 16 may be a polyester resin. From the viewpoint of adhesion between the sealant layer 16 and the second adhesive layer 15, the main component of the sealant layer 16 may be a polyolefin resin. From the viewpoint of the adhesion and heat resistance, the main component of the sealant layer 16 may be a polyolefin resin. The sealant layer 16 may be a film made of an acrylic resin, a film made of a polyolefin resin, or a film made of a polyester resin.

[0074] Examples of acrylic resins include polymethyl methacrylate resin (PMMA), etc. These acrylic resins may be used alone or in combination of two or more.

[0075] Polyolefin-based resins include polyethylene-based resins, polypropylene-based resins, etc. Polypropylene-based resins are resins obtained from polymerized monomers containing propylene. Examples of polypropylene-based resins include homopolypropylene, block polypropylene, and random polypropylene. These may be used alone or in combination of two or more. From the viewpoint of heat resistance and flexibility of the sealant layer 16, the polypropylene-based resin may include at least one of homopolypropylene and block polypropylene.

[0076] Examples of polyester resins include polyethylene terephthalate (PET) and polybutylene terephthalate (PBT). These polyester resins may be used alone or in combination of two or more.

[0077] The sealant layer 16 may be a single-layer film or a multi-layer film, and may be selected depending on the required function. When the sealant layer 16 has a multi-layer structure, the layers may be laminated together by coextrusion or by dry lamination.

[0078] The sealant layer 16 may contain other additive components, such as slip agents, antiblocking agents, antioxidants, light stabilizers, crystal nucleating agents, and flame retardants, as needed. Furthermore, the sealant layer 16 may contain a thermally conductive filler as another additive component. From the viewpoint of the insulating performance of the laminate 10, the thermally conductive filler may exhibit insulating properties. Zinc oxide may be included as the thermally conductive filler. In this case, hydrogen sulfide generated within the storage battery device is retained within the sealant layer 16. This can suppress corrosion of the metal foil layer 13 due to hydrogen sulfide. The content of these additive components is, for example, 15% by mass or less, 13% by mass or less, or 10% by mass or less, when the total mass of the sealant layer 16 is 100% by mass.

[0079] The thickness of the sealant layer 16 is not particularly limited, but from the viewpoint of obtaining the desired adhesive strength, thermal conductivity, processability, etc., it is, for example, 30 μm or more and 200 μm or less, 50 μm or more and 180 μm or less, or 80 μm or more and 160 μm or less.

[0080] [Method for Manufacturing Laminate] Next, a method for manufacturing the laminate 10 will be described. Note that the method for manufacturing the laminate 10 is not limited to the following method.

[0081] An example of a method for manufacturing the laminate 10 is a method in which the following steps S11 to S13 are performed in this order: Step S11: A step of forming a corrosion prevention treatment layer 14a on the surface 13a of the metal foil layer 13, and a step of forming a corrosion prevention treatment layer 14b on the surface 13b of the metal foil layer 13. Step S12: A step of bonding the corrosion prevention treatment layer 14a and the substrate layer 11 via the first adhesive layer 12. Step S13: A step of bonding the corrosion prevention treatment layer 14b and the sealant layer 16 via the second adhesive layer 15.

[0082] <Step S11> In step S11, a corrosion prevention treatment layer 14a is formed on the surface 13a of the metal foil layer 13, and a corrosion prevention treatment layer 14b is formed on the surface 13b of the metal foil layer 13. The corrosion prevention treatment layers 14a and 14b may be formed separately or simultaneously. In one example, a corrosion prevention treatment agent (base material of the corrosion prevention treatment layer) is applied to the surfaces 13a and 13b of the metal foil layer 13, and then dried, cured, and baked in sequence to simultaneously form the corrosion prevention treatment layers 14a and 14b. Alternatively, a corrosion prevention treatment agent is applied to the surface 13a of the metal foil layer 13, and then dried, cured, and baked in sequence to form the corrosion prevention treatment layer 14a. Then, the corrosion prevention treatment layer 14b may be formed on the surface 13b of the metal foil layer 13 in a similar manner. The order in which the corrosion prevention treatment layers 14a and 14b are formed is not particularly limited. The corrosion prevention treatment agent used to form the corrosion prevention treatment layer 14 a may be different from or the same as the corrosion prevention treatment agent used to form the corrosion prevention treatment layer 14 b. The method for applying the corrosion prevention treatment agent is not particularly limited, and examples of methods that can be used include gravure coating, gravure reverse coating, roll coating, reverse roll coating, die coating, bar coating, kiss coating, comma coating, and small diameter gravure coating.

[0083] <Step S12> In step S12, the corrosion prevention treatment layer 14a and the base layer 11 are bonded together by a method such as dry lamination using an adhesive that forms the first adhesive layer 12. In step S12, a heat treatment may be performed to promote the adhesion of the first adhesive layer 12. From the viewpoint of the molding curl resistance of the base layer 11, the temperature during the heat treatment may be 140°C or lower, or 120°C or lower.

[0084] <Step S13> After step S12, a laminate is formed in which the substrate layer 11, the first adhesive layer 12, the corrosion prevention treatment layer 14a, the metal foil layer 13, and the corrosion prevention treatment layer 14b are laminated in this order. The corrosion prevention treatment layer 14b of this laminate and the sealant layer 16 are bonded together by a method such as dry lamination using an adhesive that forms the second adhesive layer 15. In step S13, a heat treatment may be performed to promote the adhesion of the second adhesive layer 15. From the viewpoint of the molding curl resistance of the substrate layer 11, the temperature during the heat treatment may be 140°C or lower, or 120°C or lower.

[0085] The laminate 10 is obtained through the steps S11 to S13 described above. The order of steps in the method for manufacturing the laminate 10 is not limited to a method in which the steps S11 to S13 are performed sequentially. For example, the order of the steps may be changed as appropriate, such as performing step S12 before performing step S11.

[0086] <Example of use of laminate> Fig. 2 is a perspective view showing a storage battery device according to one embodiment. As shown in Fig. 2, the storage battery device 50 includes an energy storage element 52, two metal terminals (current extraction terminals) 53 for extracting current from the energy storage element 52 to the outside, and an outer bag 54 for hermetically housing the energy storage element 52.

[0087] The outer bag 54 is formed using the laminate 10 to have a bag body 54a and a seal portion 54b provided on the bag body 54a, and is used as a container for accommodating the energy storage elements 52. That is, the laminate 10 is used as an outer packaging material for a storage battery device. In the laminate 10, the base material layer 11 is the outermost layer, and the sealant layer 16 is the innermost layer. For example, the outer bag 54 is formed by folding one laminate 10 in half and heat-sealing the peripheral portions so that the base material layer 11 is on the outer side of the storage battery device 50 and the sealant layer 16 is on the inner side of the storage battery device 50. Alternatively, the outer bag 54 is formed by stacking two laminates 10 and heat-sealing the peripheral portions.

[0088] The metal terminal 53 is sandwiched by an outer bag 54 with the sealant layer 16 on the inside. The metal terminal 53 may be sandwiched by the outer bag 54 via a tab sealant. The metal terminal 53 is a part of the current collector that is taken out to the outside of the laminate 10, and is made of a metal foil such as copper foil or aluminum foil.

[0089] The storage battery device 50 may be, for example, a lithium-ion battery, a nickel-metal hydride battery, a lead-acid battery, or an all-solid-state battery containing an organic electrolyte. When the storage battery device 50 is an all-solid-state battery, the laminate 10 is used as an outer bag 54, which is an outer casing material for the all-solid-state battery, and the energy storage element 52 contains a solid electrolyte. When the storage battery device 50 is an all-solid-state battery, the storage battery device 50 may be operated in a high-temperature environment from the viewpoint of battery performance. In this case, the adhesive used in the outer bag 54 (e.g., the first adhesive layer 12 and the second adhesive layer 15 of the laminate 10) tends to soften. It has been found that if the elastic modulus of the softened adhesive is too low in a high-temperature environment (particularly, 120°C or higher and 150°C or lower), the adhesive's adhesive strength significantly decreases, resulting in delamination within the adhesive. However, it has also been found that if the elastic modulus of the adhesive is too high even in a high-temperature environment, the adhesive does not adequately disperse stress, resulting in delamination at the surface of the adhesive layer.

[0090] In the laminate 10 according to the present embodiment, which was realized based on the above findings, the second adhesive layer 15 contains an acid-modified polyolefin adhesive having good moisture barrier properties, and the modulus of elasticity (80°C modulus) obtained by force curve measurement of the second adhesive layer 15 at a cross section of the laminate in an 80°C environment using a scanning probe microscope is 3 MPa or more and 100 MPa or less. By using a second adhesive layer 15 that satisfies the above modulus of elasticity in a high-temperature environment, the second adhesive layer 15 can exhibit good adhesiveness in a high-temperature environment, even when it contains an acid-modified polyolefin adhesive. Therefore, the occurrence of interlayer delamination of the laminate 10 due to the second adhesive layer 15 can be suppressed. Therefore, in one example, a laminate 10 that exhibits good moisture barrier properties and can be used in a high-temperature environment can be provided.

[0091] In one example, when the second elastic modulus is obtained by measuring the force curve of the second adhesive layer 15 at a cross section of the laminate 10 using a scanning probe microscope in a 25°C environment, the ratio of the 80°C elastic modulus divided by the second elastic modulus may be 0.5% or more and 10% or less. Furthermore, the ratio of the 80°C elastic modulus divided by the second elastic modulus may be 0.5% or more and 5% or less. In this case, even when an acid-modified polyolefin adhesive is included, the second adhesive layer 15 can exhibit better adhesiveness in a high-temperature environment.

[0092] In one example, the acid-modified polyolefin adhesive may be a reaction product of an acid-modified polyolefin and a polyfunctional isocyanate. The reaction product has a crosslinked structure formed by the reaction of a polar group contained in the acid-modified polyolefin with a polyfunctional isocyanate compound. This increases the glass transition temperature of the reaction product contained in the polyolefin adhesive, making it difficult for the molecular chains in the polymer compound to disentangle. This makes it difficult for the gaps between the molecules in the polymer compound to widen, thereby improving the moisture barrier properties of the second adhesive layer 15. In addition, the inclusion of the crosslinked structure improves the heat resistance of the second adhesive layer 15.

[0093] In one example, the polyfunctional isocyanate may include an isocyanurate-type polyfunctional isocyanate compound, which further improves the moisture barrier property and heat resistance of the second adhesive layer 15.

[0094] In one example, the laminate 10 includes a corrosion prevention treatment layer 14b located between the metal foil layer 13 and the second adhesive layer 15 and provided on the surface 13b of the metal foil layer 13, and the corrosion prevention treatment layer 14b may be in contact with the second adhesive layer 15. In this case, peeling of the metal foil layer 13 from the second adhesive layer 15 in a high-temperature environment is effectively prevented.

[0095] In one example, the sealant layer 16 is in contact with the second adhesive layer 15, and the main component of the sealant layer 16 may be a polyolefin resin. In this case, peeling of the sealant layer 16 from the second adhesive layer 15 in a high-temperature environment is effectively prevented.

[0096] In one example, the main component of the sealant layer 16 may be a polyester resin, which can improve the heat resistance of the sealant layer 16.

[0097] (Modifications) Next, a laminate according to a modification of the above embodiment will be described. In the description of the modification, descriptions that overlap with the above embodiment will be omitted, and only differences will be described. In other words, to the extent technically possible, the description of the above embodiment may be used appropriately in the modification.

[0098] The laminate according to the modified example has a layer structure similar to that of the laminate 10 according to the above embodiment. In addition, the maximum adhesive strength of the second adhesive layer included in the laminate according to the modified example satisfies the parameters described below. The elastic modulus of the second adhesive layer included in the laminate according to the modified example may or may not satisfy the parameters shown in the above embodiment. That is, in the modified example, the elastic modulus obtained by measuring the force curve of the second adhesive layer in a cross section of the laminate using a scanning probe microscope in an environment of 80°C may be less than 3 MPa or greater than 100 MPa.

[0099] <Maximum adhesive force of second adhesive layer> In this modification, the maximum adhesive force of the second adhesive layer obtained in a 25°C environment is defined as the first maximum adhesive force, and the maximum adhesive force of the second adhesive layer obtained in an 80°C environment is defined as the second maximum adhesive force. In this case, the ratio obtained by dividing the second maximum adhesive force by the first maximum adhesive force is, for example, 70% or more and 300% or less. In this case, the second adhesive layer can exhibit good adhesiveness (sealing strength) even in a high-temperature environment (for example, 80°C or more and 150°C or less). The maximum adhesive force is the force applied to the second adhesive layer when peeling it off. The higher the viscosity of the second adhesive layer, the greater the maximum adhesive force of the second adhesive layer tends to be.

[0100] In a modified example, by setting the ratio within the above range, the seal strength of the second adhesive layer at 150°C is 10 N / cm or more. The seal strength of the second adhesive layer at 150°C may be 30 N / cm or more, or 40 N / cm or more. The seal strength of the second adhesive layer in the modified example corresponds to the peel strength between the sealant layer and the metal foil layer (or the corrosion prevention treatment layer) via the second adhesive layer, and can be obtained, for example, by the method described in the following examples.

[0101] The first maximum adhesive force is not particularly limited, and is, for example, 5 nN or more and 15 nN or less. The second maximum adhesive force is, for example, 7 nN or more and 40 nN or less, 7 nN or more and 30 nN or less, 8 nN or more and 20 nN or less, or 8 nN or more and 15 nN or less. The ratio of the second maximum adhesive force divided by the first maximum adhesive force may be 73% or more and 273% or less, 100% or more and 273% or less, 100% or more and 250% or less, or 70% or more and 250% or less. From the viewpoint of preventing peeling inside the second adhesive layer in the modified example, the ratio may be 80% or more, 100% or more, or 120% or more. From the viewpoint of preventing interfacial peeling between the second adhesive layer and the sealant layer, and preventing interfacial peeling between the second adhesive layer and the corrosion prevention treatment layer, the above ratio may be 250% or less, 200% or less, or 150% or less.

[0102] In a modified example, the first maximum adhesive force of the second adhesive layer and the second maximum adhesive force of the second adhesive layer are each obtained using a scanning probe microscope (SPM) and a cross-section of the laminate. When the maximum adhesive forces are obtained at multiple locations on the cross-section in a 25°C environment, the average value of the maximum adhesive forces corresponds to the first maximum adhesive force. Similarly, when the maximum adhesive forces are obtained at multiple locations on the cross-section in an 80°C environment, the average value of the maximum adhesive forces corresponds to the first maximum adhesive force. In one example, each maximum adhesive force corresponds to the absolute value of the minimum load obtained when a cantilever of an SPM is pressed into the cross-section with a constant load and then the cantilever is pulled out. The absolute value is calculated, for example, using analysis software for the SPM. Each maximum adhesive force of the second adhesive layer is obtained, for example, by the method described in the following examples.

[0103] The maximum adhesive strength of the adhesive layer can be controlled, for example, by the structure, molecular weight, etc. of the components contained in the adhesive. In one example, the more acid-modified groups contained in the adhesive layer, the higher the maximum adhesive strength of the adhesive layer in a high-temperature environment tends to be. Furthermore, when the components contained in the adhesive layer are the same, the higher the molecular weight of the component, the higher the maximum adhesive strength of the adhesive layer in a high-temperature environment tends to be. The maximum adhesive strength of the adhesive layer may also be controllable by the type and amount of curing agent, aging time, etc.

[0104] As described in the above embodiment, when the storage battery device 50 is operated in a high-temperature environment, the adhesive used in the outer bag 54 tends to soften. It has been found that if the viscosity of the softened adhesive is too low in a high-temperature environment (particularly, 120°C or higher and 150°C or lower), the elastic modulus of the adhesive significantly decreases, resulting in delamination within the adhesive. However, it has also been found that if the viscosity of the adhesive is too high even in a high-temperature environment, the adhesive does not adequately disperse stress, resulting in delamination on the surface of the adhesive layer.

[0105] In a laminate according to a modified example realized based on the above findings, the second adhesive layer contains an acid-modified polyolefin adhesive having good moisture barrier properties, and the ratio of the second maximum adhesive strength in the second adhesive layer divided by the first maximum adhesive strength is 70% or more and 300% or less. By using a second adhesive layer satisfying this ratio, even when an acid-modified polyolefin adhesive is included, the second adhesive layer can exhibit good adhesion in high-temperature environments. Therefore, the occurrence of interlayer delamination of the laminate due to the second adhesive layer can be suppressed. Therefore, the laminate according to the modified example can exhibit the same effects as those of the above embodiment.

[0106] In a modified example, the ratio of the second maximum adhesive force divided by the first maximum adhesive force may be 73% or more and 273% or less. Also, the ratio of the second maximum adhesive force divided by the first maximum adhesive force may be 125% or more and 273% or less. In this case, even if an acid-modified polyolefin adhesive is contained, the second adhesive layer can exhibit better adhesiveness in a high-temperature environment.

[0107] Laminates according to one aspect of the present disclosure are, for example, as described in [1] to

[13] below, and have been described in detail based on the above-mentioned embodiments and modified examples. [1] A laminate including a base layer, a first adhesive layer, a metal foil layer, a second adhesive layer, and a sealant layer, which are laminated in this order, wherein the second adhesive layer contains an acid-modified polyolefin adhesive, and wherein the elastic modulus obtained by force curve measurement of the second adhesive layer at a cross section of the laminate using a scanning probe microscope at an environment of 80°C is 3 MPa or more and 100 MPa or less. [2] The laminate according to [1], wherein, when a second elastic modulus is obtained by force curve measurement of the second adhesive layer at a cross section of the laminate using a scanning probe microscope at an environment of 25°C, the ratio obtained by dividing the elastic modulus by the second elastic modulus is 0.5 or more and 10 or less. [3] The laminate according to [2], wherein the ratio obtained by dividing the elastic modulus by the second elastic modulus is 0.5 or more and 5 or less. [4] A laminate comprising a base material layer, a first adhesive layer, a metal foil layer, a second adhesive layer, and a sealant layer, which are laminated in this order, wherein the second adhesive layer contains an acid-modified polyolefin adhesive, and wherein, when a maximum adhesive force obtained by force curve measurement of the second adhesive layer at a cross section of the laminate using a scanning probe microscope at 25°C is defined as a first maximum adhesive force, and a maximum adhesive force obtained by force curve measurement of the second adhesive layer at the cross section of the laminate at 80°C is defined as a second maximum adhesive force, the ratio of the second maximum adhesive force divided by the first maximum adhesive force is 70% or more and 300% or less. [5] The laminate according to [4], wherein the ratio of the second maximum adhesive force divided by the first maximum adhesive force is 73% or more and 273% or less. [6] The laminate according to [5], wherein the ratio of the second maximum adhesive force divided by the first maximum adhesive force is 125% or more and 273% or less. [7] The laminate according to any one of [1] to [6], wherein the acid-modified polyolefin adhesive is a reaction product of an acid-modified polyolefin and a polyfunctional isocyanate. [8] The laminate according to [7], wherein the polyfunctional isocyanate includes an isocyanurate-type polyfunctional isocyanate compound.[9] The laminate according to any one of [1] to [8], further comprising a corrosion prevention treatment layer located between the metal foil layer and the second adhesive layer and provided on the surface of the metal foil layer, wherein the corrosion prevention treatment layer is in contact with the second adhesive layer.

[10] The laminate according to any one of [1] to [9], wherein the sealant layer is in contact with the second adhesive layer, and wherein the main component of the sealant layer is a polyolefin-based resin.

[11] The laminate according to any one of [1] to

[10] , wherein the main component of the sealant layer is a polyester-based resin.

[12] The laminate according to any one of [1] to

[11] , which is an exterior packaging material for a storage battery device.

[13] The laminate according to any one of [1] to

[12] , which is an exterior packaging material for an all-solid-state battery.

[0108] However, one aspect of the present disclosure is not limited to the above embodiment and the above [1] to

[13] . One aspect of the present disclosure can be further modified within the scope of the gist thereof. For example, in the above embodiment, the corrosion prevention treatment layer is provided on both sides of the metal foil layer, but this is not limited thereto. The corrosion prevention treatment layer may be provided on only one side of the metal foil layer, or no corrosion prevention treatment layer may be provided.

[0109] The present disclosure will be specifically described below based on examples, but the present disclosure is not limited to these examples.

[0110] <Base layer (thickness: 25 μm)> A polyethylene terephthalate film, one surface of which was corona-treated, was prepared.

[0111] <First adhesive> A urethane resin (manufactured by Mitsui Chemicals, Inc., product name "main agent: Takelac A-515 (solid content concentration 50% by mass), curing agent: Takenate D-140 (solid content concentration 74% by mass)") was prepared as the material for the first adhesive layer. These materials were mixed in a ratio of 100 parts by mass of main agent to 30 parts by mass of curing agent, and diluted with ethyl acetate to a solid content concentration of 30% by mass to prepare the first adhesive.

[0112] <Metal Foil Layer (Thickness: 35 μm)> Annealed and degreased soft aluminum foil (manufactured by Toyo Aluminum K.K., "8079 material") was prepared.

[0113] <First corrosion inhibitor treatment agent (CL-1) and second corrosion inhibitor treatment agent (CL-2)> (CL-1): A "sodium polyphosphate-stabilized cerium oxide sol" was used, adjusted to a solids concentration of 10% by mass using distilled water as the solvent. The sodium polyphosphate-stabilized cerium oxide sol was obtained by blending 10 parts by mass of sodium phosphate with 100 parts by mass of cerium oxide. (CL-2): A composition consisting of 90% by mass of "polyallylamine (manufactured by Nitto Boseki Co., Ltd.)" and 10% by mass of "polyglycerol polyglycidyl ether (manufactured by Nagase ChemteX Corporation)" was used, adjusted to a solids concentration of 5% by mass using distilled water as the solvent. First and second corrosion inhibitor treatment layers were provided on the metal foil layer by the following procedure. That is, (CL-1) was applied to both surfaces of the metal foil layer in a dry coating amount of 70 mg / m. ２ The resulting layer was coated by microgravure coating so that the coating amount was 20 mg / m, and then baked in a drying unit at 200°C. ２ By applying the coating by microgravure coating so that the coating was as follows, composite layers consisting of (CL-1) and (CL-2) were formed as the first and second corrosion prevention treatment layers. This composite layer exhibits corrosion prevention performance by combining the two types of (CL-1) and (CL-2).

[0114] <Second adhesive> The following (1) to (5) were prepared as main agents. In addition, a solution containing "Coronate HXR" manufactured by Tosoh Corporation was prepared as a polyfunctional isocyanate compound. Next, one of the main agents (1) to (5) was blended with the polyfunctional isocyanate compound so that the solids mass ratio of main agent to curing agent was 90:10, to prepare a second adhesive. Of the main agents (1) to (3), main agent (1) had the largest molecular weight, and main agent (3) had the smallest molecular weight. (1) Acid-modified polyolefin (Hardlen (registered trademark), PMA-KH-based grade 1, manufactured by Toyobo MC Co., Ltd.) (2) Acid-modified polyolefin (Hardlen (registered trademark), PMA-KH-based grade 2, manufactured by Toyobo MC Co., Ltd.) (3) Acid-modified polyolefin (Hardlen (registered trademark), PMA-KH, manufactured by Toyobo MC Co., Ltd.) (4) Acid-modified polyolefin (S-5248, manufactured by Nippon Paper Industries Co., Ltd.) (5) Acid-modified polyolefin (TD-15B, manufactured by Toyobo MC Co., Ltd.)

[0115] <Sealant Layer> As the sealant layer, an 80 μm thick unstretched polypropylene film ("Aromar Film UT100" manufactured by Okamoto Corporation) and a 50 μm thick PET film ("Lumirror (registered trademark) S10" manufactured by Toray Industries, Inc.) were prepared.

[0116] [Laminate Production] Example 1 A metal foil layer was attached to a substrate layer using a first adhesive by dry lamination, and aging was performed at 80°C for 120 hours. This resulted in the metal foil layer and substrate layer being integrated via a 4 μm-thick first adhesive layer. Subsequently, a second adhesive containing the main component (1) was applied to the exposed surface of the metal foil layer using a bar coater, and the second adhesive was then heated and dried at 100°C for 1 minute. This resulted in a 3 μm-thick second adhesive layer. Subsequently, a sealant layer (an 80 μm-thick unstretched polypropylene film) was attached to the metal foil layer via the second adhesive layer using a desktop laminator. The temperature at which the sealant layer and metal foil layer were bonded was 100°C. Subsequently, aging was performed at 40°C for 168 hours. This resulted in the production of a laminate including a substrate layer, a first adhesive layer, a metal foil layer, a second adhesive layer, and a sealant layer, which were laminated in this order.

[0117] Example 2 A laminate was produced in the same manner as in Example 1, except that a second adhesive containing the main component (2) was used.

[0118] Example 3 A laminate was produced in the same manner as in Example 1, except that a second adhesive containing the main component (3) was used.

[0119] Example 4 A laminate was produced in the same manner as in Example 1, except that a second adhesive containing the main agent (4) was used.

[0120] Example 5 A laminate was produced in the same manner as in Example 1, except that a PET film having a thickness of 50 μm was used as the sealant layer.

[0121] Comparative Example 1 A laminate was produced in the same manner as in Example 1, except that a second adhesive containing the main agent (5) was used.

[0122] <Measurement of properties of second adhesive layer> A portion of the laminate was cut out in each of Examples 1 to 5 and Comparative Example 1. Then, a cross-section sample in which the cross section of the second adhesive layer was exposed from the cut-out laminate was prepared by the following method.

[0123] <Cross-Section Sample Preparation> First, the front and back surfaces of the cut laminate were subjected to corona treatment. The laminate was then cut into 2 mm x 3 mm strips with a razor, and the cut film pieces were embedded in resin. A visible light-curing resin ("Aronix LCR D-800" manufactured by Toa Gosei Co., Ltd.) was used as the resin. The film pieces were embedded in the resin and then cured by light irradiation. After the resin cured, the embedded film pieces were fixed in an AFM sample holder insert (product name) manufactured by Leica Microsystems. The fixed film pieces were then trimmed and cross-sectioned with a glass knife at room temperature (25°C). The cross-section was then cut with a diamond knife until a mirror finish was obtained, with a cutting speed of 3 mm / s and a cutting film thickness of 500 nm. An ultramicrotome (EM UC7 manufactured by Leica Microsystems) was used as the cross-section cutting device. The cutting direction was horizontal to the interface of each layer included in the film piece. The cut sample (cross-section sample) was cut into a thin piece of 1 mm or less, and then the sample was fixed to an AFM sample disk with a two-component epoxy adhesive (High Quick A, manufactured by Cemedine Co., Ltd.). With the cross-section sample fixed to the AFM sample disk, the shape measurement and property measurement described below were performed.

[0124] <Elastic Modulus Measurement and Maximum Adhesion Force Measurement> Next, as characteristic measurements, the elastic modulus and maximum adhesion force of the second adhesive layer included in the cross-sectional sample were measured using a scanning probe microscope (SPM) by the following methods. Below, the elastic modulus of the second adhesive layer in a 25°C environment (25°C elastic modulus), the elastic modulus of the second adhesive layer in an 80°C environment (80°C elastic modulus), the maximum adhesion force of the second adhesive layer in a 25°C environment (25°C maximum adhesion force), and the maximum adhesion force of the second adhesive layer in an 80°C environment (80°C maximum adhesion force) were measured. The 25°C elastic modulus corresponds to the average value of the elastic modulus of the second adhesive layer when the cross-sectional sample was at 25°C. The 80°C elastic modulus corresponds to the average value of the elastic modulus of the second adhesive layer when the cross-sectional sample was at 80°C. The 25°C maximum adhesion force corresponds to the maximum adhesion force of the second adhesive layer when the cross-sectional sample was at 25°C. When the maximum adhesive strength is measured at multiple locations on the second adhesive layer from the cross-sectional sample in an environment of 25°C, the average value of the maximum adhesive strengths corresponds to the maximum adhesive strength at 25°C. The maximum adhesive strength at 80°C corresponds to the maximum adhesive strength of the second adhesive layer when the cross-sectional sample is at 80°C. When the maximum adhesive strength is measured at multiple locations on the second adhesive layer from the cross-sectional sample in an environment of 80°C, the average value of the maximum adhesive strengths corresponds to the maximum adhesive strength at 80°C.

[0125] To set the cross-sectional sample to 80°C, a temperature-controlled heater (Polyheater) manufactured by Oxford Instruments is attached to the SPM. When the cross-sectional sample is heated using the temperature-controlled heater, the stage on which the cross-sectional sample is placed is heated at 10°C / min. When the temperature of the stage reaches 80°C, the temperature is maintained for 10 minutes, and then the elastic modulus and maximum adhesive strength of the second adhesive layer are measured. This allows the 80°C elastic modulus and maximum adhesive strength of the second adhesive layer to be measured.

[0126] The cross section of the second adhesive layer in the cross-sectional sample was subjected to shape measurement, elastic modulus measurement, and maximum adhesive force measurement using an SPM (scanning probe microscope). The SPM used was a "JupiterXR (trade name)" manufactured by Oxford Instruments. The cantilever (measurement probe) used for the SPM was a "Biosphere B50-FM (trade name)" manufactured by Nanotools (tip radius: 50 nm, spring constant: 2.8 N / m). In measuring the shape of the cross-sectional sample and calculating the elastic modulus and maximum adhesive force of the second adhesive layer, the cantilever tip radius was determined by referring to the individual characteristic values ​​of the product, and the cantilever spring constant and optical lever sensitivity were determined using values ​​obtained using the GetReal method, which is a calibration function of the SPM. Calibration using the GetReal method always used values ​​at room temperature (25°C). Therefore, even if the cross-sectional sample was at 80°C, for example, the room temperature values ​​were used in the calibration.

[0127] First, the cross-sectional sample was scanned perpendicular to the layer interface using the SPM's AC mode (tapping mode) with a field of view of 1 μm × 1 μm and a scanning speed of 2 Hz. The center of the field of view was set to the center of the film thickness of the cross section of the second adhesive layer. Next, the SPM's contact mode was used to obtain force curves (load-displacement curves) when the cantilever was pressed into and pulled out of the second adhesive layer under conditions of a maximum load of 5 nN and a test speed of 500 nm / s. Force curves were obtained at 100 points (10 vertical x 10 horizontal) at 100 nm intervals within the field of view. Force curves with a displacement of 500 nm or more were obtained for both the cantilever press and the cantilever pull. For the cross-sectional sample, measurements were performed at three locations per sample level, resulting in a total of 300 force curves.

[0128] The obtained force curve was analyzed using an elastic contact model of the Johnson-Kendall-Roberts (JKR) theory to calculate the elastic modulus of the second adhesive layer. The elastic modulus was calculated using the JKR theory by fitting analysis using SPM's analysis software, with the sample's elastic modulus, displacement origin, and maximum adhesive force as fitting parameters. The analysis range for each point on the force curve was the range starting from the load and displacement when the load first reached "(maximum load - minimum load) x 0.65 + minimum load" during the load change during pull-out after reaching the maximum load, and ending with the load and displacement when the minimum load was reached.

[0129] The maximum adhesive force was defined as the absolute value of the minimum load obtained when the cantilever of the SPM was pressed into the cross section of the second adhesive layer with a constant load (5 nN) and then pulled out. The absolute value was calculated, for example, using the analysis software of the SPM.

[0130] Using the above procedure, the average value of the elastic modulus of 300 points of the force curve obtained for each sample level was calculated. The measurement results of the 25°C elastic modulus of the second adhesive layer, the measurement results of the 80°C elastic modulus of the second adhesive layer, and the ratio obtained by dividing the 80°C elastic modulus by the 25°C elastic modulus for Examples 1 to 5 and Comparative Example 1 are shown in Table 1 below.

[0131] Using the above procedure, the average value of the maximum adhesive force of 300 force curves obtained for each sample level was calculated. The measurement results of the maximum adhesive force of the second adhesive layer at 25°C, the measurement results of the maximum adhesive force of the second adhesive layer at 80°C, and the ratios obtained by dividing the maximum adhesive force at 80°C by the maximum adhesive force at 25°C for Examples 1 to 5 and Comparative Example 1 are shown in Table 2 below.

[0132] [Evaluation of Seal Strength] (Production of Packages) The laminates obtained in each Example and Comparative Example 1 were folded so that one part of the sealant layer overlapped the other, and then sealed using a heat sealer. Packages were thus formed. The sealing conditions in Examples 1 to 4 and Comparative Example 1 were 200°C, 0.6 MPa, and 5 seconds. The sealing conditions in Example 5 were 280°C, 0.6 MPa, and 5 seconds.

[0133] (Seal Strength in a 25°C Environment) A sealed laminate (package) cut to a width of 10 mm was left in a high-temperature environment of 25°C for 5 minutes. Thereafter, the seal strength in a 25°C environment (i.e., the peel strength of the fused portion between one part of the sealant layer and another part) was measured by a T-peel test using a tensile tester (manufactured by Shimadzu Corporation) at a tensile speed of 50 mm / min. The measurement results of the seal strength (25°C seal strength) of the above laminates in a 25°C environment for Examples 1 to 5 and Comparative Example 1 are shown in Table 1.

[0134] (Seal strength in a 150°C environment) The seal strength in a 150°C environment (150°C seal strength) was measured in the same manner as the seal strength in a 25°C environment, except that the temperature at which the laminate was left after sealing was 150°C and the temperature at which the T-peel test was performed was 150°C. The measurement results of the seal strength in a 150°C environment for Examples 1 to 5 and Comparative Example 1 are shown in Table 1 below.

[0135]

[0136]

[0137] 10...Laminate (exterior material for storage battery device), 11...Base material layer, 12...First adhesive layer, 13...Metal foil layer, 14a, 14b...Corrosion prevention treatment layer, 15...Second adhesive layer, 16...Sealant layer, 50...Storage battery device.

Claims

1. A laminate comprising a base layer, a first adhesive layer, a metal foil layer, a second adhesive layer, and a sealant layer, which are laminated in this order, wherein the second adhesive layer contains an acid-modified polyolefin adhesive, and wherein the modulus of elasticity obtained by force curve measurement of the second adhesive layer in a cross section of the laminate using a scanning probe microscope in an 80°C environment is 3 MPa or more and 100 MPa or less.

2. The laminate described in claim 1, wherein when a second elastic modulus is obtained by measuring a force curve of the second adhesive layer at the cross section of the laminate using a scanning probe microscope in an environment of 25°C, the ratio of the elastic modulus divided by the second elastic modulus is 0.5 or more and 10 or less.

3. The laminate according to claim 2, wherein the ratio of the elastic modulus divided by the second elastic modulus is 0.5 or more and 5 or less.

4. A laminate comprising a base material layer, a first adhesive layer, a metal foil layer, a second adhesive layer, and a sealant layer, which are laminated in this order, wherein the second adhesive layer contains an acid-modified polyolefin adhesive, and wherein, when the maximum adhesive force obtained by force curve measurement of the second adhesive layer at a cross section of the laminate using a scanning probe microscope at 25°C is defined as the first maximum adhesive force, and the maximum adhesive force obtained by force curve measurement of the second adhesive layer at the cross section of the laminate at 80°C is defined as the second maximum adhesive force, the ratio of the second maximum adhesive force divided by the first maximum adhesive force is 70% or more and 300% or less.

5. The laminate according to claim 4, wherein the ratio of the second maximum adhesive force divided by the first maximum adhesive force is 73% or more and 273% or less.

6. The laminate according to claim 5, wherein the ratio of the second maximum adhesive force divided by the first maximum adhesive force is 125% or more and 273% or less.

7. The laminate according to any one of claims 1 to 6, wherein the acid-modified polyolefin adhesive is a reaction product of an acid-modified polyolefin and a polyfunctional isocyanate.

8. The laminate according to claim 7, wherein the polyfunctional isocyanate includes an isocyanurate-type polyfunctional isocyanate compound.

9. A laminate according to any one of claims 1 to 6, further comprising a corrosion prevention treatment layer located between the metal foil layer and the second adhesive layer and provided on the surface of the metal foil layer, the corrosion prevention treatment layer being in contact with the second adhesive layer.

10. The laminate according to any one of claims 1 to 6, wherein the sealant layer is in contact with the second adhesive layer, and the main component of the sealant layer is a polyolefin resin.

11. The laminate according to any one of claims 1 to 6, wherein the main component of the sealant layer is a polyester-based resin.

12. The laminate according to any one of claims 1 to 6, which is an exterior material for a storage battery device.

13. The laminate according to any one of claims 1 to 6, which is an exterior material for an all-solid-state battery.

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