JP6183032B2 - Exterior materials for lithium-ion batteries - Google Patents

Description

  The present invention relates to a packaging material for a lithium ion battery.

As a secondary battery for consumer use used in portable terminal devices such as personal computers and mobile phones, and video cameras, lithium-ion batteries that are ultra-thin and miniaturized while being high energy have been actively developed.
As an outer packaging material of a lithium ion battery, a laminated film having a multilayer structure is used from the advantage that it is lightweight and the battery shape can be freely selected instead of a conventional metal can. Moreover, the exterior material using such a laminate film is not only flexible in the shape of the battery, but also lightweight, high heat dissipation, and low cost. Application to electric vehicle batteries is also being attempted.
The laminate film is constructed by laminating a sealant layer (heat-fusible film) on one surface of an aluminum foil layer via an adhesive layer and a base material layer (plastic film) on the other surface via an adhesive layer. (Base layer / adhesive layer / aluminum foil layer / adhesive layer / sealant layer) is generally used, and another intermediate layer is optionally provided between these layers. For adhesion between the base material layer and the aluminum foil layer, an adhesive for dry lamination such as polyurethane adhesive is usually used (for example, Patent Documents 1 to 4).

A lithium ion battery using a laminate film type exterior material is, for example, a positive electrode material, a negative electrode material, and a separator as a battery body part in a molded product obtained by deep drawing the above-described laminate film by cold molding (deep drawing molding). At the same time, an electrolyte layer made of an electrolytic solution or a polymer gel impregnated with the electrolytic solution is accommodated and heat sealed by heat sealing. As the electrolytic solution, an electrolytic solution in which a lithium salt is dissolved in an aprotic solvent (propylene carbonate, ethylene carbonate, dimethyl carbonate, diethyl carbonate, ethyl methyl carbonate, or the like) is used.
The electrolytic solution is highly permeable to the sealant layer. Therefore, in a lithium ion battery, the electrolyte solution that has penetrated into the sealant layer may reduce the laminate strength between the aluminum foil layer and the sealant layer, and the electrolyte solution may eventually leak out. In addition, lithium salts such as LiPF ₆ and LiBF ₄ that are electrolytes may generate hydrofluoric acid by a hydrolysis reaction. Hydrofluoric acid causes corrosion of the metal surface and a decrease in laminate strength between the layers of the laminate film. Therefore, the exterior material is required to have a corrosion prevention performance against an electrolytic solution and hydrofluoric acid.
In order to provide corrosion prevention performance against electrolytic solution and hydrofluoric acid in response to such demands, the aluminum foil surface may be subjected to corrosion prevention treatment such as degreasing treatment, hydrothermal transformation treatment, anodizing treatment, and chemical conversion treatment. Has been done.

On the other hand, the exterior material is required to have excellent moldability. In other words, since the energy density is determined depending on how the cells and electrolytes can be accommodated in the lithium ion battery, in order to increase the capacity, the molding depth is further increased when the exterior material is molded into the battery shape. We need to be deep.
Molding of the exterior material is generally performed by cold molding (deep drawing) using a mold, but if the molding depth is too deep at this time, cracks and pinholes will occur in the stretched part by molding, and as a battery Is unreliable. Therefore, it is important how the molding depth can be increased without impairing reliability. In particular, in large-scale applications such as electric vehicles, there is a demand for higher energy density from the viewpoint of battery performance for taking out a large current, but excellent reliability and long-term storage stability are also required.

As an exterior material with improved moldability in cold forming, the base material layer has specific tensile strength and elongation in four directions of 0 °, 45 °, 90 °, and 135 ° with respect to the stretching direction. An exterior material using a stretched polyamide film or a stretched polyester film with little directionality (Patent Document 1), an exterior material using a heat-resistant resin film having an impact strength of 30000 J / m or more as a base material layer (Patent Document 2), An exterior material (Patent Document 3) using a biaxially stretched polyamide film having a density of 1142 to 1146 kg / cm ³ as the base material layer, and a heat-resistant resin stretched film having a shrinkage rate of 2 to 20% was used as the base material layer. An exterior material (Patent Document 4) has been proposed.

Japanese Patent No. 3567230 Japanese Patent No. 4431822 Japanese Patent No. 4422171 JP 2006-331897 A

However, the exterior material described in Patent Document 1 has a great restriction on the manufacturing process for obtaining a stretched film having a predetermined direction of mechanical properties. For example, the production of the stretched film is limited to the inflation method, and a stretched film produced by another method, for example, a cast method cannot be applied. The film used in Comparative Example 1 of Patent Document 1 has a good balance with the strength in the above four directions (168, 135, 151, 141: unit N / mm ² ), but stretched physical properties (112, 66 , 89, 67: unit%) and a minimum / maximum ratio of 59% (the directionality of the mechanical properties is large). Such mechanical properties are characteristic of films produced by the casting method.
The value of impact strength of 30000 J / m or more described in Patent Document 2 is extremely wide. For example, the impact strength of commercially available stretched polyamide resin film is generally 30000 J / m or more, and excellent moldability is obtained. It may not be possible.
The density described in Patent Document 3 is only a specific gravity value of a general polyamide film, and an excellent moldability may not be obtained.
Since the exterior material described in Patent Document 4 has a large thermal shrinkage rate of the base material, there is a risk that defects such as curling may occur in a baking process or the like in battery manufacture.
Therefore, there is a demand for new means that can improve the moldability of the exterior material.

  This invention is made | formed in view of the said situation, Comprising: It aims at providing the exterior material for lithium ion batteries which has the outstanding moldability.

The present invention has the following aspects.
[1] At least a metal foil layer, an inner adhesive layer, and a sealant layer are laminated in this order on one surface side of the base material layer, and a corrosion prevention treatment layer is formed on the adhesive layer side surface of the metal foil layer. A lithium-ion battery exterior material provided with
The base material layer is composed of a biaxially stretched film obtained by coextrusion of the following thermoplastic resin (a) and the following thermoplastic resin (b),
A packaging material for a lithium ion battery, wherein the layer of the thermoplastic resin (b) is disposed closest to the metal foil layer in the base material layer, and the layer and the metal foil layer are in contact with each other.
Thermoplastic resin (a): aromatic polyester resin or polyamide resin.
Thermoplastic resin (b): Modified thermoplastic graft-modified with at least one unsaturated carboxylic acid derivative selected from the group consisting of unsaturated carboxylic acids, unsaturated carboxylic acid anhydrides, and unsaturated carboxylic acid esters resin.
[2] At least a metal foil layer, an inner adhesive layer, and a sealant layer are laminated in this order on one surface side of the base material layer, and an adhesion improving treatment layer is provided on the base material side surface of the metal foil layer. And a lithium ion battery exterior material in which a corrosion prevention treatment layer is provided on the surface of the metal foil layer on the adhesive layer side,
The base material layer is composed of a biaxially stretched film obtained by coextrusion of the following thermoplastic resin (a) and the following thermoplastic resin (b),
The outer layer material for a lithium ion battery, wherein the thermoplastic resin (b) layer is disposed closest to the metal foil layer in the base material layer, and the layer and the adhesion improving treatment layer are in contact with each other. .
Thermoplastic resin (a): aromatic polyester resin or polyamide resin.
Thermoplastic resin (b): Modified thermoplastic graft-modified with at least one unsaturated carboxylic acid derivative selected from the group consisting of unsaturated carboxylic acids, unsaturated carboxylic acid anhydrides, and unsaturated carboxylic acid esters resin.
[3] In the base material layer, the thickness of the thermoplastic resin (a) is 1 μm or more and 50 μm or less, and the thickness of the thermoplastic resin layer (b) is 0.1 μm or more and 5 μm or less. The packaging material for a lithium ion battery according to [1] or [2].
[4] The exterior material for a lithium ion battery according to [2] , wherein the base material layer and the metal foil layer or the adhesion improving treatment layer are adhered by heat treatment.

  ADVANTAGE OF THE INVENTION According to this invention, the exterior material for lithium ion batteries which has the outstanding moldability can be provided.

It is a schematic sectional drawing which shows an example of the exterior material for lithium ion batteries of this invention. It is a schematic sectional drawing which shows the other example of the exterior material for lithium ion batteries of this invention. It is a perspective view which shows an example of a lithium ion battery. It is a perspective view which shows an example of the manufacturing process of a lithium ion battery.

≪Lithium-ion battery exterior material≫
Hereinafter, a lithium ion battery exterior material (hereinafter, simply referred to as “exterior material”) of the present invention will be described in detail with reference to the accompanying drawings.

<First embodiment>
FIG. 1 is a schematic cross-sectional view of an exterior material 1 according to the first embodiment of the present invention.
The exterior material 1 is formed by laminating a metal foil layer 15, an inner adhesive layer 17, and a sealant layer 18 in this order on one surface of the base material layer 10, and the inner adhesive layer 17 of the metal foil layer 15. A corrosion prevention treatment layer 16 is provided on the side surface.
The packaging material 1 is used with the base material layer 10 as the outermost layer and the sealant layer 18 as the innermost layer.

[Base material layer]
The base material layer 10 is composed of a biaxially stretched film (hereinafter also referred to as a film (A)) obtained by coextrusion of the following thermoplastic resin (a) and the following thermoplastic resin (b). And a thermoplastic resin (a) layer (hereinafter referred to as a thermoplastic resin (a) layer) 10a and a thermoplastic resin (b) layer (hereinafter referred to as a thermoplastic resin (b) layer) 10b. In the base material layer 10, the thermoplastic resin (b) layer 10 b is disposed closer to the metal foil layer 15 than the thermoplastic resin (a) layer 10 a and is in contact with the metal foil layer 15.
Thermoplastic resin (a): aromatic polyester resin or polyamide resin.
Thermoplastic resin (b): Modified thermoplastic graft-modified with at least one unsaturated carboxylic acid derivative selected from the group consisting of unsaturated carboxylic acids, unsaturated carboxylic acid anhydrides, and unsaturated carboxylic acid esters resin.

  Of the thermoplastic resin (a), the aromatic polyester resin imparts rigidity and chemical resistance to the film (A), and the polyamide resin imparts toughness to the film (A). The thermoplastic resin (b) imparts stress propagation to the film (A) and adhesion to the metal foil layer 15. By using a film formed by coextrusion of these thermoplastic resins to form a biaxially stretched film as the base material layer, the exterior material 1 has excellent moldability. For example, compared with the case where a film of thermoplastic resin (a) and a metal foil are laminated by dry lamination, a molding depth that can be molded without causing cracks or pinholes in the stretched portion during cold molding is increased. Can be deep.

(Thermoplastic resin (a) layer)
The thermoplastic resin (a) layer 10a is formed from a thermoplastic resin (a).
As the thermoplastic resin layer (a), an aromatic polyester resin or a polyamide resin is used.

The aromatic polyester resin is a polyester resin having an aromatic ring in the structure.
Examples of the aromatic polyester resin include a polyester resin obtained by polymerization (polycondensation) of an aromatic dibasic acid and a diol.
Examples of the aromatic dibasic acid include isophthalic acid, terephthalic acid, naphthalenedicarboxylic acid and the like, and any one of them may be used alone or two or more of them may be used in combination.
Examples of the diol include aliphatic diols such as ethylene glycol, propylene glycol, butanediol, neopentyl glycol, methylpentanediol, hexanediol, heptanediol, octanediol, nonanediol, decanediol, and dodecanediol; cyclohexanediol, hydrogenated An alicyclic diol such as xylylene glycol; an aromatic diol such as xylylene glycol; and the like may be used. Any one of them may be used alone or two or more may be used in combination.
The aromatic polyester resin may be obtained by polymerizing an aliphatic dibasic acid together with an aromatic dibasic acid and a diol. Examples of the aliphatic dibasic acid include succinic acid, glutaric acid, adipic acid, pimelic acid, speric acid, azelaic acid, sebacic acid, brassylic acid, and the like. You may use together.
Specific examples of the aromatic polyester resin include polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polyethylene naphthalate (PEN), and the like. These may be used alone or in combination of two or more.
As the aromatic polyester resin, polyethylene terephthalate is preferable in terms of excellent rigidity.

Examples of the polyamide resin include poly ε-capramide (nylon 6), polyhexamethylene adipamide (nylon 66), polyhexamethylene sepacamide (nylon 610), polyaminoundecamide (nylon 11), and polylauryl amide. (Nylon 12), polymetaxylylene adipamide (MXD6), and copolymers thereof. These may be used alone or in combination of two or more.
As the polyamide resin, nylon 6 and nylon 66 are preferable in terms of excellent toughness.

Components other than the thermoplastic resin (a) may be blended with the thermoplastic resin (a) as long as the effects of the present invention are not impaired.
For example, at least one resin selected from the group consisting of an ethylene copolymer resin obtained by copolymerizing maleic anhydride as a soft component with the thermoplastic resin (a) and an aliphatic polyester resin (hereinafter also referred to as a soft resin). .) May be blended. By blending a soft resin with the thermoplastic resin (a), more excellent moldability can be obtained.

Examples of the ethylene copolymer resin obtained by copolymerizing maleic anhydride include ethylene-α and β-unsaturated carboxylic acid alkyl ester-maleic anhydride copolymers.
Examples of the α and β unsaturated carboxylic acid alkyl esters include those obtained by esterifying an α and β unsaturated carboxylic acid with an alcohol having an alkyl group having 1 to 4 carbon atoms.
Examples of α and β unsaturated carboxylic acids include monocarboxylic acids or dicarboxylic acids having 3 to 8 carbon atoms, or metal salts or acid anhydrides thereof. Specifically, acrylic acid, methacrylic acid, maleic acid, fumaric acid, itaconic acid, maleic anhydride and the like can be mentioned, and a commercial product includes Lexpearl manufactured by Nippon Polyethylene.
Examples of the aliphatic polyester resin include polycaprolactone, and examples of commercially available products include Plaxel manufactured by Daicel Chemical Industries.

Various rubber components such as various polyester elastomers, olefin elastomers, and polyamide elastomers may be blended with the thermoplastic resin (a) for the purpose of obtaining other modification effects.
If necessary, various additives such as a lubricant, an antistatic agent, an antiblocking agent, and inorganic fine particles may be added to the thermoplastic resin (a).

  The thickness of the thermoplastic resin (a) layer 10a is preferably 1 μm to 50 μm, and more preferably 10 μm to 30 μm. When the thickness of the thermoplastic resin (a) layer 10a is within the above range, the moldability of the exterior material 1 is good. If it is thinner than 1 μm, there is a high risk of cracking during molding. If it is thicker than 50 μm, the function expression in terms of moldability will be saturated.

(Thermoplastic resin (b) layer)
The thermoplastic resin (b) layer 10b is formed from a thermoplastic resin (b).
The thermoplastic resin layer (b) was graft-modified with at least one unsaturated carboxylic acid derivative selected from the group consisting of unsaturated carboxylic acids, acid anhydrides of unsaturated carboxylic acids, and esters of unsaturated carboxylic acids. A modified thermoplastic resin is used.
Since the base material layer 10 has the thermoplastic resin (b) layer, the base material layer 10 and the metal foil layer 15 can be directly heated without using a conventionally used two-component curable polyurethane adhesive. It can be adhered by lamination. Moreover, since the thermoplastic resin (b) is a hard material having higher rigidity than the two-component curable polyurethane adhesive, it is possible to propagate stress during molding efficiently. Therefore, the moldability of the exterior material 1 is improved.

Examples of the unsaturated carboxylic acid include acrylic acid, methacrylic acid, maleic acid, fumaric acid, itaconic acid, tetrahydrophthalic acid, bicyclo [2,2,1] hept-2-ene-5,6 dicarboxylic acid, and the like. Can be mentioned.
Examples of the unsaturated carboxylic acid anhydride include dicarboxylic acid anhydrides such as maleic acid among the above unsaturated carboxylic acids.
As ester of unsaturated carboxylic acid, what esterified said unsaturated carboxylic acid with alcohol is mentioned.

As the thermoplastic resin layer (b), a resin obtained by modifying a polyolefin-based resin, a styrene-based elastomer, or a polyester-based elastomer with the unsaturated carboxylic acid derivative is preferable because of having excellent stress propagation properties and adhesiveness.
Hereinafter, a polyolefin resin graft-modified with an unsaturated carboxylic acid derivative is grafted with an acid-modified polyolefin resin, and a styrene elastomer graft-modified with an unsaturated carboxylic acid derivative is graft-modified with an acid-modified styrene elastomer resin and an unsaturated carboxylic acid derivative. The polyester elastomer resin is referred to as an acid-modified polyester elastomer resin.

Examples of the polyolefin resin in the acid-modified polyolefin resin include low density polyethylene, medium density polyethylene, high density polyethylene, copolymer of ethylene and α-olefin other than ethylene, homo, block, or random polypropylene, other than propylene and propylene. Examples of the copolymer with α-olefin include those obtained by copolymerizing polar molecules such as acrylic acid and methacrylic acid, and crosslinked polyolefin. A polyolefin resin may be used individually by 1 type, and may use 2 or more types together.
Examples of the styrenic elastomer in the acid-modified styrenic elastomer include copolymerization of styrene (hard segment) and butadiene, isoprene, or a hydrogenated product thereof (soft segment).
Examples of the polyester elastomer in the acid-modified polyester elastomer include a copolymer of crystalline polyester (hard segment) and polyalkylene ether glycol (soft segment).

For example, the thermoplastic resin layer (b) reacts by heating 0.2 to 100 parts by mass of the unsaturated carboxylic acid derivative component in the presence of a radical initiator with respect to 100 parts by mass of the thermoplastic resin as a base. Is obtained.
50-200 degreeC or more is preferable and, as for reaction temperature, 60-200 degreeC is more preferable. Although the reaction time depends on the production method, in the case of a melt graft reaction by a twin screw extruder, 2 to 30 minutes, which is within the residence time of the extruder, is preferable, and 5 to 10 minutes is more preferable. In addition, the denaturation reaction can be carried out under normal pressure or pressurized conditions.
Examples of the radical initiator used in the modification reaction include organic oxides. The organic oxide can be selected depending on temperature conditions and reaction time. For example, alkyl peroxide, aryl peroxide, acyl peroxide, ketone peroxide, peroxyketal, peroxycarbonate, and peroxyester are preferable. Di-t-butyl peroxide, 5-2, dimethyl-2,5-di-t-butylperoxy-hexyne-3, dicumyl peroxide are more preferred.

You may use a commercially available thing as a thermoplastic resin layer (b).
Typical examples of the acid-modified polyolefin resin include polyolefin resins modified with maleic anhydride, such as Admer manufactured by Mitsui Chemicals, Modic manufactured by Mitsubishi Chemical, and Adtex manufactured by Nippon Polyethylene.
Examples of the acid-modified styrenic elastomer include AK Elastomer's Tuftec and Kraton Polymer's Kraton.
Examples of the acid-modified polyester elastomer include Primalloy manufactured by Mitsubishi Chemical Corporation.

Components other than the thermoplastic resin (b) may be blended with the thermoplastic resin (b) as long as the effects of the present invention are not impaired.
For example, various additives such as a lubricant, an antistatic agent, an antiblocking agent, and inorganic fine particles may be added to the thermoplastic resin (b) 10b as necessary.

The thickness of the thermoplastic resin (b) layer 10b is preferably 0.1 μm or more, more preferably 0.5 μm or more from the viewpoint that the adhesion between the thermoplastic resin (a) layer 10a and the metal foil layer 15 is increased. More preferred. In addition, the thickness of the thermoplastic resin (b) layer 10b is preferably 5 μm or less, more preferably 3 μm or less, from the viewpoint of improving stress propagation and moldability.
Therefore, the thickness of the thermoplastic resin (b) layer 10b is preferably 0.1 μm or more and 5 μm or less, and particularly preferably 0.5 μm or more and 3 μm or less.

(Method for producing film (A))
The film (A) can be produced by forming a film by coextrusion of the thermoplastic resin (a) and the thermoplastic resin (b) and subjecting the obtained film to a biaxial stretching treatment.
The co-extrusion method and the biaxial stretching method are not particularly limited, and known methods can be employed. For example, co-extrusion can be performed using a melt extruder equipped with a T die, an infiltration die, and the like.
For example, the following method is mentioned as an example of the method of manufacturing a film (A) using T die.
Each of the thermoplastic resins (a) and (b) is melted and formed into a film by co-extrusion with an extruder equipped with a T die, and the formed molten resin is air knife cast method, electrostatic application cast method, etc. Is cooled on a rotating cooling drum by a known casting method. Then, after preheating the obtained unstretched film using a roller-type longitudinal stretching machine composed of a group of heating rollers having different peripheral speeds, the unstretched film is heated to the glass transition point or higher of the thermoplastic resin (a). Longitudinal stretching is performed between the stretching roll and a cooling roll for cooling the film. Further, the film after longitudinal stretching is guided to a tender and preheated at 50 to 70 ° C, and then stretched at 60 to 110 ° C. If necessary, the ratio between the longitudinal draw ratio and the transverse draw ratio is controlled, and heat treatment and relaxation treatment are performed at 210 to 220 ° C. in the tender.
The biaxial stretching is not limited to the sequential biaxial stretching described above, and may be simultaneous biaxial stretching. The draw ratio and heat setting temperature of the film (A) can be appropriately selected.

[Metal foil layer]
As metal foil which comprises the metal foil layer 15, various metal foils, such as aluminum and stainless steel, can be used, and aluminum foil is preferable from the surface of moisture resistance, ductility, throat workability, and cost.
As the aluminum foil, a general soft aluminum foil can be used, and an aluminum foil containing iron is preferable from the viewpoint of excellent pinhole resistance and extensibility during molding.
0.1-9.0 mass% is preferable and, as for content of iron in aluminum foil (100 mass%), 0.5-2.0 mass% is more preferable. When the iron content is 0.1% by mass or more, pinhole resistance and spreadability are improved. If the iron content is 9.0% by mass or less, flexibility is improved.

As the metal foil, an aluminum foil that has been subjected to a degreasing treatment is preferable from the viewpoint of resistance to electrolytic solution.
The degreasing treatment is roughly classified into a wet type and a dry type.
Examples of the wet type degreasing treatment include acid degreasing and alkali degreasing.
Examples of the acid used for acid degreasing include inorganic acids such as sulfuric acid, nitric acid, hydrochloric acid, and hydrofluoric acid. These inorganic acids may be used individually by 1 type, and may use 2 or more types together. Moreover, you may mix | blend various metal salts used as supply sources, such as Fe ion and Ce ion, with these inorganic acids as needed from the point which the etching effect of aluminum foil improves.
As an alkali used for alkali degreasing, sodium hydroxide etc. are mentioned as a thing with a high etching effect, for example. Moreover, what mix | blended weak alkali type and surfactant is mentioned. These degreasing and etching processes are performed by an immersion method or a spray method.
Examples of the dry-type degreasing treatment include a method performed in a step of annealing aluminum. In addition to the degreasing treatment, frame treatment, corona treatment, and the like can be given. Furthermore, a degreasing treatment in which pollutants are oxidatively decomposed / removed by active oxygen generated by irradiation with ultraviolet rays having a specific wavelength is also included.
The degreasing treatment may be performed only on one side of the aluminum foil layer or on both sides.

  The thickness of the metal foil layer 15 is preferably 9 to 200 μm and more preferably 15 to 100 μm from the viewpoint of barrier properties against water vapor and the like, pinhole resistance, and workability.

[Corrosion prevention treatment layer]
The corrosion prevention treatment layer 16 serves to suppress the corrosion of the metal foil layer 15 due to hydrofluoric acid generated by the reaction between the electrolytic solution and moisture, and to improve the interaction with the metal foil layer 15 to be described later. It plays the role which improves the adhesive force with 17.
The corrosion prevention treatment layer 16 is formed by performing a corrosion prevention treatment on the metal foil constituting the metal foil layer 15.
Examples of the corrosion prevention treatment include degreasing treatment, hydrothermal alteration treatment, anodizing treatment, chemical conversion treatment, coating type corrosion prevention treatment for applying a coating agent having corrosion prevention performance, or a combination of two or more of these treatments. Is mentioned.
Among the above-described treatments, in particular, the hydrothermal modification treatment and the anodizing treatment dissolve the surface of the metal foil (aluminum foil) with the treating agent and further form a metal compound having excellent corrosion resistance. To the corrosion prevention treatment layer 16, it is included in the definition of the chemical conversion treatment. In the present invention, the corrosion prevention treatment layer 16 can be formed only by a pure coating treatment not included in the definition of the chemical conversion treatment, such as a method using a coating agent containing a rare earth element oxide sol described later. .

Degreasing treatment includes acid degreasing and alkali degreasing. Examples of the acid degreasing include a method using the above-described inorganic acid such as sulfuric acid, nitric acid, hydrochloric acid, and hydrofluoric acid alone or a mixture thereof. In addition, as acid degreasing, by using an acid degreasing agent in which a fluorine-containing compound such as monosodium ammonium difluoride is dissolved with the inorganic acid, not only the degreasing effect of the metal foil, but also a passive metal fluoride is obtained. It is possible to form. Such a layer is effective in terms of resistance to hydrofluoric acid. Examples of the alkaline degreasing include a method using sodium hydroxide and the like.
Examples of the hydrothermal modification treatment include boehmite treatment in which a metal foil is immersed in boiling water to which triethanolamine is added.
Examples of the anodizing treatment include alumite treatment.
Examples of the chemical conversion treatment include various chemical conversion treatments including chromate treatment, zirconium treatment, titanium treatment, vanadium treatment, molybdenum treatment, calcium phosphate treatment, strontium hydroxide treatment, cerium treatment, ruthenium treatment, or a combination thereof.
These hydrothermal modification treatment, anodizing treatment, and chemical conversion treatment are preferably performed after the above-described degreasing treatment is performed on the metal foil in advance. These chemical conversion treatments are not limited to the wet type, and may be a coating type in which these treatment agents are mixed with a resin component.

The coating agent used in the coating type corrosion prevention treatment for coating the coating agent having the corrosion prevention performance contains at least one selected from the group consisting of rare earth oxide sols, anionic polymers, and cationic polymers. Things. In particular, a method using a coating agent containing a rare earth element oxide sol is preferable.
The method using a coating agent containing a rare earth element oxide sol is a pure coating type corrosion prevention treatment, and this method can impart a corrosion prevention effect to a metal foil even with a general coating method. Is possible. In addition, the layer formed using the rare earth element oxide sol has a corrosion prevention effect (inhibitor effect) of the metal foil, and is also a suitable material from the environmental viewpoint.

The rare earth element oxide sol is obtained by dispersing rare earth element oxide fine particles (for example, particles having an average particle diameter of 100 nm or less) in a liquid dispersion medium.
Examples of rare earth element oxides include cerium oxide, yttrium oxide, neodymium oxide, and lanthanum oxide. Of these, cerium oxide is preferred.
As the liquid dispersion medium of the rare earth element oxide sol, for example, various solvents such as water-based, alcohol-based, hydrocarbon-based, ketone-based, ester-based, and ether-based solvents can be used. Among these, an aqueous system is preferable.

The rare earth element oxide sol preferably contains a dispersion stabilizer in order to stabilize the dispersion of the rare earth element oxide particles.
Examples of the dispersion stabilizer include inorganic acids such as nitric acid, hydrochloric acid and phosphoric acid, organic acids such as acetic acid, malic acid, ascorbic acid and lactic acid, and salts thereof.
Among these dispersion stabilizers, phosphoric acid and its salts are not only “sol dispersion stabilization” but also “adhesion improvement with metal foil layer” due to chelating ability, and metal ions eluted under the influence of hydrofluoric acid. It is preferable because effects such as “providing electrolyte resistance” by trapping (passivation formation) and “increasing the cohesive strength of the rare earth element oxide layer” by easily causing dehydration condensation of phosphoric acid even at low temperatures can be expected.
Examples of phosphoric acid or a salt thereof used as a dispersion stabilizer include orthophosphoric acid, pyrophosphoric acid, metaphosphoric acid, and alkali metal salts and ammonium salts thereof. Of these, condensed phosphoric acid such as trimetaphosphoric acid, tetrametaphosphoric acid, hexametaphosphoric acid, and ultrametaphosphoric acid, or alkali metal salts and ammonium salts thereof are preferable for the functional expression in the exterior material. In addition, considering the dry film-forming properties (drying capacity, heat amount) when forming a layer composed of rare earth oxides by various coating methods using rare earth element oxide sol, from the point of excellent reactivity at low temperatures, Sodium salt is more preferred. As the phosphate, a water-soluble salt is preferable.
The amount of phosphoric acid (or a salt thereof) in the rare earth element oxide sol is preferably 1 part by mass or more and more preferably 5 parts by mass or more with respect to 100 parts by mass of the rare earth element oxide. When the content is 1 part by mass or more, the sol is stabilized well and it is easy to fulfill the function as an exterior material.
The blending amount of phosphoric acid (or a salt thereof) with respect to 100 parts by mass of the rare earth element oxide may be in a range not accompanied by a decrease in the function of the rare earth element oxide sol, and is 100 parts by mass with respect to 100 parts by mass of the rare earth element oxide. Or less, more preferably 50 parts by mass or less, and still more preferably 20 parts by mass or less.

Since the corrosion prevention treatment layer formed by the rare earth oxide sol described above is an aggregate of inorganic particles, the cohesive force of the layer itself may be low even after a dry curing step. Therefore, in order to supplement the cohesive strength of the corrosion prevention treatment layer in this case, it is preferable that the composite is composed of the following anionic polymer.
Examples of the anionic polymer include polymers having a carboxy group. For example, a copolymer obtained by copolymerizing a monomer mixture containing poly (meth) acrylic acid (or a salt thereof) and (meth) acrylic acid as a main component. Can be mentioned.
Examples of the copolymer component of the copolymer include alkyl (meth) acrylate monomers (alkyl groups include methyl, ethyl, n-propyl, i-propyl, n-butyl, and i-butyl groups. , T-butyl group, 2-ethylhexyl group, cyclohexyl group, etc.); (meth) acrylamide, N-alkyl (meth) acrylamide, N, N-dialkyl (meth) acrylamide (alkyl groups include methyl group, ethyl group) , N-propyl group, i-propyl group, n-butyl group, i-butyl group, t-butyl group, 2-ethylhexyl group, cyclohexyl group, etc.), N-alkoxy (meth) acrylamide, N, N-di Alkoxy (meth) acrylamide (as the alkoxy group, methoxy group, ethoxy group, butoxy group, isobutoxy group, etc.), N Amide group-containing monomers such as methylol (meth) acrylamide and N-phenyl (meth) acrylamide; hydroxyl group-containing monomers such as 2-hydroxyethyl (meth) acrylate and 2-hydroxypropyl (meth) acrylate; glycidyl (meth) acrylate and allyl Glycidyl group-containing monomers such as glycidyl ether; Silane-containing monomers such as (meth) acryloxypropyltrimethoxysilane and (meth) acryloxypropyltriethoxylane; Isocyanate group-containing monomers such as (meth) acryloxypropyl isocyanate It is done.

  As described above, the anionic polymer plays a role of improving the stability of the corrosion prevention treatment layer (rare earth element oxide layer) obtained using the rare earth element oxide sol. The effect is that the hard and brittle rare earth element oxide layer is protected with an anionic polymer, and phosphate-derived cations (particularly sodium ions) optionally contained in the rare earth oxide sol are captured (cation catcher). There are effects. In other words, when an alkali metal ion such as sodium or an alkaline earth metal ion is contained in the corrosion prevention treatment layer obtained using the rare earth element oxide sol, the corrosion prevention treatment starts from the place containing the ion. The layer tends to deteriorate. Therefore, the resistance of the corrosion prevention treatment layer is improved by fixing sodium ions and the like contained in the rare earth oxide sol by the anionic polymer.

The corrosion prevention treatment layer combined with the anionic polymer and the rare earth element oxide sol has the same corrosion prevention performance as the corrosion prevention treatment layer formed by the chromate treatment. Such an effect is further improved by crosslinking an anionic polymer which is essentially water-soluble as described above.
Examples of the crosslinking agent used for the crosslinking of the anionic polymer include compounds having an isocyanate group, a glycidyl group, a carboxy group, and an oxazoline group.

Examples of the compound having an isocyanate group include tolylene diisocyanate, xylylene diisocyanate or hydrogenated products thereof, diisocyanates such as hexamethylene diisocyanate, 4,4′diphenylmethane diisocyanate or hydrogenated products thereof, isophorone diisocyanate; or these isocyanates. Polyisocyanates such as adducts obtained by reacting polyhydric alcohols with polyhydric alcohols such as trimethylolpropane, burette obtained by reacting with water, or isocyanurates which are trimers; or these polyisocyanates Examples include blocked polyisocyanates obtained by blocking isocyanates with alcohols, lactams, oximes and the like.
Examples of the compound having a glycidyl group include ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, propylene glycol, dipropylene glycol, tripropylene glycol, polypropylene glycol, 1,4-butanediol, 1,6-hexanediol, Epoxy compounds in which epichlorohydrin is allowed to react with glycols such as neopentyl glycol; polyhydric alcohols such as glycerin, polyglycerin, trimethylolpropane, pentaerythritol, sorbitol, and epoxy compounds in which epichlorohydrin is allowed to react; terephthalic acid phthalate And epoxy compounds obtained by reacting dicarboxylic acids such as oxalic acid and adipic acid with epichlorohydrin.
Examples of the compound having a carboxy group include various aliphatic or aromatic dicarboxylic acids. Further, poly (meth) acrylic acid or alkali (earth) metal salt of poly (meth) acrylic acid may be used.
As the compound having an oxazoline group, for example, a low molecular compound having two or more oxazoline units, or a polymerizable monomer such as isopropenyl oxazoline, (meth) acrylic acid, (meth) acrylic acid alkyl ester And those obtained by copolymerizing acrylic monomers such as hydroxyalkyl (meth) acrylate.

  Further, the anionic polymer may be selectively reacted with an amine and a functional group to form a siloxane bond at the crosslinking point, like a silane coupling agent. In this case, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropyltriethoxysilane, β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, γ-chloropropylmethoxysilane, vinyltrichlorosilane, γ -Mercaptopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, N-β (aminoethyl) -γ-aminopropyltrimethoxysilane, γ-isocyanatopropyltriethoxysilane and the like can be used. Of these, epoxy silane, amino silane, and isocyanate silane are preferable in consideration of reactivity with an anionic polymer or a copolymer thereof.

1-50 mass parts is preferable with respect to 100 mass parts of anionic polymers, and, as for the ratio of these crosslinking agents with respect to anionic polymer, 10-20 mass parts is more preferable. When the ratio of the crosslinking agent is 1 part by mass or more with respect to 100 parts by mass of the anionic polymer, a crosslinked structure is easily formed. When the ratio of the crosslinking agent is 50 parts by mass or less with respect to 100 parts by mass of the anionic polymer, the pot life of the coating liquid is improved.
The method of crosslinking the anionic polymer is not limited to the crosslinking agent, and may be a method of forming ionic crosslinking using a titanium or zirconium compound.

When the corrosion prevention treatment layer is formed by the above-described coating type corrosion prevention treatment, an inclined structure is formed between the metal foil layer 15 and the corrosion prevention treatment layer 16 unlike the chemical conversion treatment represented by the chromate treatment. There is no need.
In the chemical conversion treatment typified by the chromate treatment, as described above, in order to form the inclined structure, the metal foil is treated with a chemical conversion treatment agent containing, in particular, hydrofluoric acid, hydrochloric acid, nitric acid, sulfuric acid or a salt thereof. Next, chromium and non-chromium compounds are allowed to act. However, since the chemical conversion treatment uses an acid as the chemical conversion treatment agent, it involves deterioration of the working environment and corrosion of the coating apparatus. For example, the chromate treatment using hexavalent chromium is known as a method for imparting corrosion resistance to an electrolytic solution and hydrofluoric acid to an aluminum foil, but hexavalent chromium as in the Rhos regulations and REACH regulations in Europe. Are now treated as environmentally hazardous substances. Therefore, chromate treatment using trivalent chromium has been carried out. However, since hexavalent chromium is used as a starting material for obtaining trivalent chromium, there will be a move to abolish chromium in the future. there is a possibility. Therefore, when considering application to an electric vehicle in consideration of the influence on the environment in particular, it is preferable to provide corrosion prevention performance against an electrolytic solution and hydrofluoric acid by a treatment that does not use a chromium compound at all.
Since the anticorrosion treatment layer formed by the above-mentioned coating type anticorrosion treatment does not need to form an inclined structure with respect to the metal foil, the properties of the coating agent are limited to acidic, alkaline, neutrality, etc. I do not receive it. Moreover, sufficient corrosion prevention performance can be imparted without using any chromium compound. Therefore, a favorable working environment can be realized, and it is effective as an alternative in consideration of the environmental hygiene of the chromium compound used for the chromate treatment.

The corrosion prevention treatment layer 16 has a laminated structure in which a layer containing a cationic polymer is laminated on a layer formed from the above-mentioned rare earth oxide sol or a composite of a rare earth oxide sol and an anionic polymer. Also good.
Examples of the cationic polymer include polyethyleneimine, an ionic polymer complex composed of a polymer having polyethyleneimine and a carboxylic acid, a primary amine-grafted acrylic resin obtained by grafting a primary amine on an acrylic main skeleton, polyallylamine or a derivative thereof, amino Phenol etc. are mentioned.
The layer containing a cationic polymer is preferably a layer formed from a cationic polymer and a crosslinking agent. Examples of the crosslinking agent used in combination with the cationic polymer include those having a functional group capable of reacting with an amine / imine such as a carboxyl group or a glycidyl group. As the crosslinking agent used in combination with the cationic polymer, a polymer having a carboxylic acid that forms an ionic polymer complex with polyethyleneimine can also be used. For example, a polycarboxylic acid (salt) such as polyacrylic acid or an ionic salt thereof, or the like And a copolymer having a carboxy group such as carboxymethylcellulose or an ionic salt thereof.
Examples of polyallylamine include homopolymers or copolymers of allylamine, allylamine amide sulfate, diallylamine, dimethylallylamine, and the like. These amines may be free amines or may be stabilized with acetic acid or hydrochloric acid. Moreover, you may use a maleic acid, sulfur dioxide, etc. as a copolymer component. Furthermore, the type which gave the thermal crosslinking property by partially methoxylating a primary amine can also be used, and aminophenol can also be used. In particular, allylamine or a derivative thereof is preferable.
In addition, although this cationic polymer is also described as one component constituting the corrosion prevention treatment layer, the reason for this is that various compounds are used to impart the electrolyte resistance and hydrofluoric acid resistance required for the exterior material. This is because, as a result of various investigations using the above, it has been found that the cationic polymer itself is a compound that can impart electrolyte solution resistance and hydrofluoric acid resistance. This factor is presumed to be because the metal foil is suppressed from being damaged by supplementing fluorine ions with a cationic group (anion catcher). The cationic polymer is also very preferable from the viewpoint of improving the adhesion between the corrosion prevention treatment layer 16 and the inner adhesive layer 17.
Since the cationic polymer is water-soluble like the anionic polymer described above, the water resistance can be improved by forming a crosslinked structure using the crosslinking agent. As described above, since a crosslinked structure can be formed even when a cationic polymer is used, when a rare earth oxide sol is used for forming the corrosion prevention treatment layer 16, instead of an anionic polymer as a protective layer thereof. Cationic polymers may be used.

As a corrosion prevention treatment layer formed by coating type corrosion prevention treatment,
(1) a layer formed only of a rare earth element oxide sol;
(2) a layer formed only of an anionic polymer,
(3) a layer formed only of a cationic polymer;
(4) Layer formed of rare earth oxide sol and anionic polymer (laminated composite),
(5) Layer (laminated composite) formed of rare earth oxide sol and cationic polymer
(6) A layer formed of a cationic polymer on a layer (laminated composite) formed of a rare earth element oxide sol and an anionic polymer,
(7) A layer formed of an anionic polymer on a layer (laminated composite) formed of a rare earth element oxide sol and a cationic polymer,
Etc.
However, the corrosion prevention treatment layer 16 is not limited to these layers.
The cationic polymer has good adhesiveness with the modified polyolefin resin mentioned in the explanation of the inner adhesive layer 17 described later. For this reason, when the inner adhesive layer 17 is formed of a modified polyolefin-based resin, a mode in which a layer formed of a cationic polymer is provided on the side in contact with the inner adhesive layer 17 (for example, the configuration (5) or the configuration (6)). preferable.

  The corrosion prevention treatment layer 16 is formed by using a treatment agent in which phosphoric acid and a chromium compound are blended in a resin binder (aminophenol or the like), such as a coating type chromate which is a known technique. In order to improve adhesion to the above-described degreasing treatment, hydrothermal modification treatment, anodizing treatment, chemical conversion treatment, or chemical conversion treatment combining these treatments, a cationic property may be used. It may be a layer subjected to a complex treatment using a polymer or an anionic polymer, or may be a layer obtained by laminating a layer made of a cationic polymer or an anionic polymer on the layer formed by the chemical conversion treatment. . Moreover, the layer formed with the coating agent obtained by making the rare earth element oxide sol and the cationic polymer or the anionic polymer into one liquid in advance may be used.

Mass per unit area of the corrosion prevention treatment layer 16 is preferably ^{0.005~0.200g / m 2, 0.010~0.100g / m} 2 is more preferable. If the mass per unit area is 0.005 g / m ² or more, a sufficient corrosion prevention function can be obtained. Even if the mass per unit area exceeds 0.200 g / m ² , the corrosion prevention function is saturated and does not change much. Further, when the rare earth oxide sol is used, since the thickness of the corrosion prevention treatment layer 16 is not more than the upper limit value, curing due to heat at the time of drying is likely to be sufficient, and the cohesive force is not easily lowered.
In addition, although the thickness of the said corrosion prevention process layer is shown by the mass per unit area, it can convert into thickness from the specific gravity.
The thickness of the corrosion prevention treatment layer is preferably 0.1 to 0.2 μm in view of the corrosion prevention function and the function as an anchor.

[Inner adhesive layer]
The inner adhesive layer 17 is a layer that bonds the metal foil layer 15 provided with the corrosion prevention treatment layer 16 and the sealant layer 18.
The adhesive components constituting the inner adhesive layer 17 are roughly classified into two types, that is, an adhesive component having a thermal laminate configuration and an adhesive component having a dry laminate configuration.

As an adhesive component having a heat laminate configuration, an acid-modified polyolefin resin is preferable. Examples of the acid-modified polyolefin-based resin include the same ones as mentioned for the thermoplastic resin (b).
The acid-modified polyolefin resin used for the inner adhesive layer 17 is preferably a maleic anhydride-modified polyolefin resin graft-modified with maleic anhydride. The acid-modified polyolefin resin imparts adhesiveness by utilizing the reactivity of the grafted unsaturated carboxylic acid derivative component with various metals or polymers containing various functional groups.
Various thermoplastic elastomers may be dispersed in the acid-modified polyolefin resin according to desired characteristics. Thereby, the residual stress generated when laminating the acid-modified polyolefin resin is released, and the viscoelastic adhesiveness is improved.
As thermoplastic elastomers, Mitsui Chemicals Toughmer, Sumitomo Chemical Tough Selenium, Mitsubishi Chemical Zelas, Montell Catalloy, Mitsui Chemicals Notio, and styrene elastomers, especially hydrogenated styrene elastomers (AK Elastomers) (Tuftec manufactured by Kuraray Co., Ltd., Septon / Hypler manufactured by Kuraray Co., Ltd., Dynalon manufactured by JSR Co., Espolex manufactured by Sumitomo Chemical Co., Ltd., and Kraton G manufactured by Kraton Polymer Co., Ltd.)

Various additives such as a flame retardant, a slip agent, an antiblocking agent, an antioxidant, a light stabilizer, and a tackifier may be blended in the adhesive component.
The inner adhesive layer having a heat laminate structure can be formed, for example, by extruding the adhesive component with an extrusion device.
In the case of a thermal laminate configuration, the thickness of the inner adhesive layer 17 is preferably 1 to 40 μm, and more preferably 5 to 20 μm.

  As an adhesive component having a dry laminate structure, for example, a two-component curable type in which an isocyanate compound having two or more functional groups is allowed to act as a curing agent on a main component such as polyester polyol, polyether polyol, acrylic polyol, carbonate polyol, and polyolefin polyol. A polyurethane adhesive is mentioned.

Examples of polyester polyols include polyols obtained by reacting one or more dibasic acids with one or more diols.
Examples of the dibasic acid include aliphatic dibasic acids such as succinic acid, glutaric acid, adipic acid, pimelic acid, speric acid, azelaic acid, sebacic acid, and brassic acid, isophthalic acid, terephthalic acid, naphthalenedicarboxylic acid, etc. An aromatic dibasic acid etc. are mentioned.
Diols include aliphatic diols such as ethylene glycol, propylene glycol, butanediol, neopentyl glycol, methylpentanediol, hexanediol, heptanediol, octanediol, nonanediol, decanediol, dodecanediol; cyclohexanediol, hydrogenated Decyclic diols such as xylylene glycol; aromatic diols such as xylylene glycol.
In addition, a hydroxyl group at both ends of the polyester polyol may be an isocyanate compound alone, or a polyester urethane polyol chain-extended using an adduct, a burette, or an isocyanurate composed of at least one isocyanate compound. . Examples of the isocyanate compound include 2,4- or 2,6-tolylene diisocyanate, xylylene diisocyanate, 4,4′-diphenylmethane diisocyanate, methylene diisocyanate, isopropylene diisocyanate, lysine diisocyanate, 2,2,4- or 2, Examples include 4,4-trimethylhexamethylene diisocyanate, isophorone diisocyanate, 4,4′-dicyclohexylmethane diisocyanate, and isopropylidene dicyclohexyl-4,4′-diisocyanate.

  Examples of the polyether polyol include ether-based polyols such as polyethylene glycol and propylene glycol, and polyether urethane polyols on which the above-described isocyanate compounds are allowed to act as chain extenders.

  As an acrylic polyol, the copolymer which has poly (meth) acrylic acid as a main component is mentioned, for example. Examples of the monomer used in the copolymer include hydroxyl group-containing monomers such as 2-hydroxyethyl (meth) acrylate and 2-hydroxypropyl (meth) acrylate; alkyl (meth) acrylate monomers (the alkyl group includes a methyl group) , Ethyl group, n-propyl group, i-propyl group, n-butyl group, i-butyl group, t-butyl group, 2-ethylhexyl group, cyclohexyl group, etc.); (meth) acrylamide, N-alkyl (meta ) Acrylamide, N, N-dialkyl (meth) acrylamide (alkyl groups include methyl, ethyl, n-propyl, i-propyl, n-butyl, i-butyl, t-butyl, 2 -Ethylhexyl group, cyclohexyl group, etc.), N-alkoxy (meth) acrylamide, N, N-dia Amoxy group-containing monomers such as koxy (meth) acrylamide (alkoxy groups such as methoxy group, ethoxy group, butoxy group, isobutoxy group, etc.), N-methylol (meth) acrylamide, N-phenyl (meth) acrylamide; 2 Hydroxyl group-containing monomers such as hydroxyethyl (meth) acrylate and 2-hydroxypropyl (meth) acrylate; glycidyl group-containing monomers such as glycidyl (meth) acrylate and allyl glycidyl ether; (meth) acryloxypropyltrimethoxysilane, (meta ) Silane-containing monomers such as acryloxypropyltriethoxylane; and isocyanate group-containing monomers such as (meth) acryloxypropyl isocyanate.

  Examples of the carbonate polyol include a polyol obtained by reacting a carbonate compound and a diol. Examples of the carbonate compound include dimethyl carbonate, diphenyl carbonate, and ethylene carbonate. Examples of the diol include the diols exemplified in the polyester polyol. Moreover, you may use the polycarbonate urethane polyol chain-extended with the said isocyanate compound.

  Examples of the polyolefin polyol include a polyol obtained by copolymerizing an olefin and a hydroxyl group-containing monomer such as 2-hydroxyethyl (meth) acrylate and 2-hydroxypropyl (meth) acrylate to deform the polyolefin skeleton, or polybutadiene diol or Examples of such hydrogenated products.

These various polyols can be used individually by 1 type or in mixture of 2 or more types according to the function and performance calculated | required.
As an isocyanate compound of a hardening | curing agent, the isocyanate compound quoted as a chain extender is mentioned, for example.
The polyurethane adhesive is subjected to aging for 4 days or more, for example, at 40 ° C. after coating, whereby the reaction of the hydroxyl group of the main agent and the isocyanate group of the curing agent proceeds to enable strong adhesion. 1-10 are preferable and, as for the molar ratio (NCO / OH) of the isocyanate group which the hardening | curing agent has with respect to the hydroxyl group which a main ingredient has, 2-5 are more preferable.

The polyurethane adhesive may contain a carbodiimide compound, an oxazoline compound, an epoxy compound, a phosphorus compound, a silane coupling agent, and the like for adhesion promotion.
In addition to the above components, various additives and stabilizers may be blended in the polyurethane-based adhesive depending on the required performance.

  Examples of the carbodiimide compound include N, N′-di-o-toluylcarbodiimide, N, N′-diphenylcarbodiimide, N, N′-di-2,6-dimethylphenylcarbodiimide, N, N′-bis (2 , 6-diisopropylphenyl) carbodiimide, N, N′-dioctyldecylcarbodiimide, N-triyl-N′-cyclohexylcarbodiimide, N, N′-di-2,2-di-t-butylphenylcarbodiimide, N-triyl- N'-phenylcarbodiimide, N, N'-di-p-nitrophenylcarbodiimide, N, N'-di-p-aminophenylcarbodiimide, N, N'-di-p-hydroxyphenylcarbodiimide, N, N'- Di-cyclohexylcarbodiimide, N, N′-di-p-toluylcarbodiimide, etc. It is below.

  Examples of the oxazoline compound include monooxazolines such as 2-oxazoline, 2-methyl-2-oxazoline, 2-phenyl-2-oxazoline, 2,5-dimethyl-2-oxazoline, and 2,4-diphenyl-2-oxazoline. Compound, 2,2 ′-(1,3-phenylene) -bis (2-oxazoline), 2,2 ′-(1,2-ethylene) -bis (2-oxazoline), 2,2 ′-(1, And dioxazoline compounds such as 4-butylene) -bis (2-oxazoline) and 2,2 ′-(1,4-phenylene) -bis (2-oxazoline).

  Examples of the epoxy compound include diglycidyl ethers of aliphatic diols such as 1,6-hexanediol, neopentyl glycol, and polyalkylene glycol; sorbitol, sorbitan, polyglycerol, pentaerythritol, diglycerol, glycerol, trimethylolpropane Polyglycidyl ethers of aliphatic polyols such as: Polyglycidyl ethers of alicyclic polyols such as cyclohexanedimethanol; Aliphatics and aromatics such as terephthalic acid, isophthalic acid, naphthalenedicarboxylic acid, trimellitic acid, adipic acid, and sebacic acid Diglycidyl esters or polyglycidyl esters of polycarboxylic acids of the following: resorcinol, bis- (p-hydroxyphenyl) methane, 2,2-bis- (p-hydroxyphenyl) propane Diglycidyl ether or polyglycidyl ether of polyphenols such as tris- (p-hydroxyphenyl) methane, 1,1,2,2-tetrakis (p-hydroxyphenyl) ethane; N, N′-diglycidylaniline, N N-glycidyl derivatives of amines such as N, N, N-diglycidyltoluidine, N, N, N ′, N′-tetraglycidyl-bis- (p-aminophenyl) methane; triglycidyl derivatives of aminofail; Examples thereof include tris (2-hydroxyethyl) isocyanurate, triglycidyl isocyanurate, orthocresol type epoxy, phenol novolac type epoxy and the like.

  Examples of phosphorus compounds include tris (2,4-di-t-butylphenyl) phosphite, tetrakis (2,4-di-t-butylphenyl) 4,4′-biphenylenephosphonite, bis (2 , 4-Di-t-butylphenyl) pentaerythritol-di-phosphite, bis (2,6-di-t-butyl-4-methylphenyl) pentaerythritol-di-phosphite, 2,2-methylenebis (4 , 6-Di-t-butylphenyl) octyl phosphite, 4,4′-butylidene-bis (3-methyl-6-tert-butylphenyl-di-tridecyl) phosphite, 1,1,3-tris (2 -Methyl-4-ditridecyl phosphite-5-t-butyl-phenyl) butane, tris (mixed mono and di-nonylphenyl) phosphite, tri (Nonylphenyl) phosphite, 4,4'-isopropylidene-bis (phenyl - dialkyl phosphite), and the like.

  Examples of the silane coupling agent include vinyltriethoxysilane, vinyltris (β-methoxyethoxy) silane, γ-methacryloxypropyltrimethoxysilane, vinyltriacetoxysilane, γ-glycidoxypropyltrimethoxysilane, and γ-glycine. Sidoxypropyltriethoxysilane, β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, γ-chloropropylmethoxysilane, vinyltrichlorosilane, γ-mercaptopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, N -Β (aminoethyl) -γ-aminopropyltrimethoxysilane and the like.

However, the polyurethane adhesive may be swollen by an electrolyte solution or hydrolyzed by hydrofluoric acid, so that a composition design such as using a main component of a skeleton that is not easily hydrolyzed and improving a crosslinking density may be performed. preferable.
Examples of the method for improving the crosslinking density include a method using dimer fatty acid, dimer fatty acid ester, dimer fatty acid hydrogenated product, or a reduced glycol thereof. The bulky hydrophobic unit of dimer fatty acid improves the crosslink density of the adhesive.
Dimer fatty acids are those obtained by dimerizing various unsaturated fatty acids, and examples of their structures include acyclic, monocyclic, polycyclic, and aromatic ring types.
The unsaturated fatty acid that is the starting material of the dimer fatty acid is not particularly limited, and examples thereof include monounsaturated fatty acids, diunsaturated fatty acids, triunsaturated fatty acids, tetraunsaturated fatty acids, pentaunsaturated fatty acids, and hexaunsaturated fatty acids. It is done. Examples of monounsaturated fatty acids include crotonic acid, myristoleic acid, palmitoleic acid, oleic acid, elaidic acid, vaccenic acid, gadoleic acid, eicosenoic acid, erucic acid, nervonic acid and the like. Examples of diunsaturated fatty acids include linoleic acid, eicosadienoic acid, and docosadienoic acid. Examples of the triunsaturated fatty acid include linolenic acid, vinolenic acid, eleostearic acid, mead acid, dihomo-γ-linolenic acid, and eicosatrienoic acid. Examples of tetraunsaturated fatty acids include stearidonic acid, arachidonic acid, eicosatetraenoic acid, and adrenic acid. Examples of the pentaunsaturated fatty acid include boseopentaenoic acid, eicosaventaenoic acid, ozbond acid, sardine acid, and tetracosaventaenoic acid. Examples of the hexaunsaturated fatty acid include docosahexaenoic acid and nisic acid. The combination of fatty acids when dimerizing fatty acids may be any combination.
Moreover, you may introduce | transduce the dibasic acid mentioned by description of the said polyester polyol by using the said dimer fatty acid as an essential component.

In addition, as a curing agent, for the purpose of improving electrolytic solution resistance (especially solubility and swelling property with respect to an electrolytic solution), a polyisocyanate alone or a mixture selected from crude tolylene diisocyanate and crude (or polymeric) diphenylmethane diisocyanate, Alternatively, it is effective to use these adduct bodies. The use of the curing agent leads to improvement in solubility and swelling property due to improvement in the crosslink density of the adhesive coating film, and since the urethane group concentration is improved, improvement in substrate adhesion is also expected.
As the above-mentioned polyester polyol chain extender, it is also preferable to use at least one polyisocyanate of the group consisting of the above-mentioned crude tolylene diisocyanate, crude (or polymeric) diphenylmethane diisocyanate, or an adduct thereof.

  Furthermore, not only the polyurethane adhesives described above, but also adhesive resins such as maleic anhydride-modified polyolefins and maleic anhydride-modified styrene copolymer elastomers described in the thermal laminate configuration can be used in various organic solvents. For the material obtained by dissolving or dispersing, the above-mentioned compound containing the isocyanate compound, carbodiimide compound, oxazoline compound, epoxy compound, phosphorus compound, silane coupling agent, etc. is used as an adhesive for dry lamination. Also good.

  As a ratio of the main agent and the curing agent in the adhesive component of the dry laminate configuration, 1 to 100 parts by mass of the curing agent is preferable with respect to 100 parts of the main agent, and more preferably 5 to 50 parts by mass. If the ratio of the said hardening | curing agent is more than a lower limit, it will be excellent in adhesiveness and electrolyte solution tolerance. If the ratio of the said hardening | curing agent is below an upper limit, it will be easy to suppress that an unreacted hardening | curing agent remains and it will have a bad influence on adhesiveness and hardness.

Various additives such as a flame retardant, a slip agent, an antiblocking agent, an antioxidant, a light stabilizer, and a tackifier may be blended in the adhesive.
The inner adhesive layer having a dry laminate structure can be formed by a general dry laminate method.
In the case of a dry laminate configuration, the thickness of the inner adhesive layer 17 is preferably 1 to 10 μm, and more preferably 2 to 5 μm.

[Sealant layer]
The sealant layer 18 is a layer that imparts sealing properties by heat sealing in the exterior material 1.
Examples of the sealant layer 18 include a film made of a polyolefin resin, an ethylene-vinyl acetate copolymer, an ethylene- (meth) acrylic acid copolymer, an esterified product thereof, or an ionic compound.
Examples of the polyolefin resin include low-density polyethylene, medium-density polyethylene, high-density polyethylene, ethylene-α olefin copolymer, polyolefin resin such as homo, block, or random polypropylene, propylene-α olefin copolymer, ethylene -Vinyl acetate copolymer, ethylene- (meth) acrylic acid copolymer, esterified product thereof or ionic cross-linked product thereof. These polyolefin resin may be used individually by 1 type, and may use 2 or more types together.

The film constituting the sealant layer 18 may be a film formed of one or more kinds of resins, or may be a film formed of two or more kinds of resins. Moreover, a single layer film may be sufficient and a multilayer film may be sufficient, and what is necessary is just to select according to the function required. For example, in terms of imparting moisture resistance, a multilayer film in which a resin such as an ethylene-cyclic olefin copolymer or polymethylpentene is interposed may be used. The ethylene-vinyl acetate copolymer portion may be a completely saponified product, or a multilayer film having a gas barrier resin such as a polyvinyl acetate copolymer portion or a completely saponified product interposed.
The sealant layer 18 may contain various additives such as a flame retardant, slip agent, anti-blocking agent, antioxidant, light stabilizer, and tackifier.
10-100 micrometers is preferable and, as for the thickness of the sealant layer 18, 20-80 micrometers is more preferable.

[Method for Manufacturing Exterior Material 1]
The exterior material 1 can be manufactured by the manufacturing method which has the following process (X1)-(X3), for example. However, the manufacturing method of the exterior material 1 is not limited to the following method.
(X1) A step of forming the corrosion prevention treatment layer 16 on one surface of the metal foil layer 15.
(X2) A step of bonding the other surface of the metal foil layer 15 (the side on which the corrosion prevention treatment layer 16 is not formed) and the surface of the base material layer 10 on the thermoplastic resin (b) layer 10b side by heat treatment.
(X3) A step of bonding the sealant layer 18 to the corrosion prevention treatment layer 16 via the inner adhesive layer 17.

(Process (X1))
The corrosion prevention treatment layer 16 is formed by performing a corrosion prevention treatment on the metal foil constituting the metal foil layer 15. Before the corrosion prevention treatment, the metal foil may be degreased.
The details of the degreasing treatment are as described above. Examples of the degreasing treatment include annealing, spraying, and dipping.
Examples of the corrosion prevention treatment include a degreasing treatment, a hydrothermal alteration treatment, an anodizing treatment, a chemical conversion treatment, a coating type corrosion prevention treatment in which a coating agent having corrosion prevention performance is applied, or a combination of two or more of these treatments. Can be mentioned. Details of these processes are as described above.
Examples of the hydrothermal transformation treatment and anodizing treatment include an immersion method. As a chemical conversion treatment method, an immersion method, a spray method, a coating method, or the like can be selected according to the type of chemical conversion treatment. As a coating method of the coating agent, various methods such as a gravure coater, a gravure reverse coater, a roll coater, a reverse roll coater, a die coater, a bar coater, a kiss coater, and a comma coater can be employed. When dry curing is required, the base material temperature can be set in the range of 60 to 300 ° C. according to the type of the corrosion prevention treatment layer.

(Process (X2))
Bonding of the metal foil layer 15 and the base material layer 10 can be performed by heat treatment such as thermal lamination or thermocompression bonding. For example, a method similar to the bonding of the sealant layer 18 by an inner layer adhesive layer having a thermal laminate configuration described later is used. Can be implemented.

(Process (X3))
In the step (X3), the corrosion prevention treatment of the laminate (the laminate in which the base material layer 10, the metal foil layer 15, and the corrosion prevention treatment layer 16 are laminated in this order) obtained through the steps (X1) and (X2). A sealant layer 18 is bonded to the layer 16 side via an inner adhesive layer 17.

In the case of a dry laminate configuration, the inner adhesive layer 17 is provided by applying the above-described adhesive component (polyurethane adhesive or the like) by a technique such as dry lamination, non-solvent lamination, or wet lamination. At this time, in order to promote adhesion, an aging (curing) treatment may be performed within a range of room temperature to 100 ° C. At this time, in order to promote adhesion, an aging (curing) treatment may be performed within a range of room temperature to 100 ° C.
Inner adhesive layer 17 may be in the range of 1 to 10 g / ^{m 2} as a dry coating amount of the adhesive component, and more preferably it is preferably provided in the range of 3 to 5 g / ^{m 2.} Sufficient laminate strength can be obtained when it is 1 g / m ² or more. If it is more than 10 g / m ^{2, the} moisture permeation performance required as a lithium battery exterior material may be reduced.

In the case of a thermal laminate configuration, the inner adhesive layer and the sealant layer may be bonded to the laminate by sandwich lamination or coextrusion lamination.
In this case, it is preferable to perform heat treatment from the viewpoint of improving the adhesion between the metal foil layer 15 and the sealant layer 18 and imparting excellent electrolytic solution resistance and hydrofluoric acid resistance. The heat treatment temperature in this case is preferably in the range from room temperature to a temperature 40 ° C. higher than the melting point of the sealant layer, as the maximum temperature reached by the laminate. The heat treatment time depends on the heat treatment temperature, and is preferably longer as the heat treatment temperature is lower.
As a heat treatment method, from the viewpoint of productivity and handling, a method of passing through a drying furnace or a baking furnace, a method of thermal lamination (thermocompression bonding), or a method of using a Yankee drum (mounted on a thermal drum) is preferable.
The step (X2) described above can also be performed by this method. However, in the case of the step (X2), the upper limit of the maximum attainable temperature is preferably a temperature that does not exceed the melting point of the thermoplastic resin (a) constituting the base material layer 10.

The packaging material 1 is obtained by the steps (X1) to (X3) described above.
In addition, the manufacturing method of the exterior material 1 is not limited to the method of implementing the said process (X1)-(X3) sequentially. For example, the step (X1) may be performed after performing the step (X2).
In order to further improve the moldability, a lubricant layer may be provided on at least one of the base material layer 10 side and the sealant layer 18 side of the obtained exterior material 1 to reduce the static friction coefficient. Examples of the lubricant include silicone, polymer wax, and aliphatic amide (such as erucic acid amide). Further, the lubricant may be preliminarily blended in a film for forming the base material layer 10 or the sealant layer 18 and precipitated by a bleed-out phenomenon.

<Second embodiment>
FIG. 2 is a schematic cross-sectional view of the packaging material 2 according to the second embodiment of the present invention. In the embodiments described below, the same reference numerals are given to the components corresponding to the first embodiment, and detailed description thereof will be omitted.
The exterior material 2 is formed by laminating a metal foil layer 15, an inner adhesive layer 17, and a sealant layer 18 in this order on one surface of the base material layer 10, and the base material 10 side of the metal foil layer 15. An adhesion improving treatment layer 19 is provided on this surface, and a corrosion prevention treatment layer 16 is provided on the surface on the inner adhesive layer 17 side.
The base material layer 10 has a thermoplastic resin (a) layer 10a and a thermoplastic resin (b) layer 10b. The thermoplastic resin (b) layer 10 b is disposed closer to the metal foil layer 15 than the thermoplastic resin (a) layer 10 a and is in contact with the corrosion prevention treatment layer 16.
The exterior material 2 of the present embodiment is provided with an adhesion improving treatment layer 19 provided on the surface of the metal foil layer 15 on the substrate 10 side, and the adhesion improving treatment layer 19 is in contact with the thermoplastic resin (b) layer 10b. This is the same as the exterior material 1 of the first embodiment.

[Adhesion improving treatment layer 19]
The adhesion improving treatment layer 19 plays a role of improving the adhesion between the thermoplastic resin (b) layer 10 b of the base material layer 10 and the metal foil layer 15. By providing the adhesion improving treatment layer 19, the adhesion between the base material layer 10 and the metal foil layer 15 is further increased, and the moldability is further improved. For example, it is possible to perform cold forming at a deeper drawing depth without causing pinholes and breakage.

  Examples of the adhesion improving treatment layer 19 include a corrosion prevention treatment layer similar to the above-described corrosion prevention treatment layer 16. Various corrosion prevention treatments (degreasing treatment, hydrothermal alteration treatment, anodizing treatment, chemical conversion treatment, coating type corrosion prevention treatment applying a coating agent having corrosion prevention performance, etc.) used for forming the corrosion prevention treatment layer 16 are Moreover, it has the effect of improving adhesiveness with the thermoplastic resin (b) layer 10b which comprises the base material layer 10. FIG.

[Method for Manufacturing Exterior Material 2]
The exterior material 2 can be manufactured by the manufacturing method which has the following process (X1 ')-(X3'), for example. However, the manufacturing method of the exterior material 2 is not limited to the following method.
(X1 ′) A step of forming the corrosion prevention treatment layer 16 on one surface of the metal foil layer 15 and forming the adhesion improving treatment layer 19 on the other surface.
(X2 ′) A step of bonding the adhesion improving treatment layer 19 formed on the metal foil layer 15 and the surface of the base material layer 10 on the thermoplastic resin (b) layer 10 b side by heat treatment.
(X3 ′) A step of bonding the sealant layer 18 to the corrosion prevention treatment layer 16 via the inner adhesive layer 17.

The step (X1 ′) can be performed in the same manner as the step (X1) except that the adhesion improving treatment layer 19 is further formed. The adhesion improving treatment layer 19 can be formed in the same manner as the corrosion prevention treatment layer 16.
Step (X2 ′) and step (X3 ′) can be carried out in the same manner as in steps (X2) and (X3), respectively.

The exterior material 2 is obtained by the steps (X1 ′) to (X3 ′) described above.
In addition, the manufacturing method of the exterior material 1 is not limited to the method of implementing the said process (X1 ')-(X3') sequentially. For example, after forming only the adhesion improving treatment layer 19 in the step (X1 ′), the step (X2 ′) may be performed, and then the corrosion prevention treatment layer 16 may be formed.
Further, for the purpose of further improving the moldability, a lubricant layer may be provided on at least one of the base material layer 10 side and the sealant layer 18 side of the obtained exterior material 2 to reduce the static friction coefficient. Examples of the lubricant include silicone, polymer wax, and aliphatic amide (such as erucic acid amide). Further, the lubricant may be preliminarily blended in a film for forming the base material layer 10 or the sealant layer 18 and precipitated by a bleed-out phenomenon.

As mentioned above, although the exterior material of this invention was demonstrated by showing 1st-2nd embodiment, the exterior material of this invention is not limited to these embodiment. Each configuration in the above embodiment, a combination thereof, and the like are examples, and the addition, omission, replacement, and other modifications of the configuration can be made without departing from the spirit of the present invention.
For example, the structure of the base material layer is not limited to a two-layer structure in which one thermoplastic resin (a) layer 10a and one thermoplastic resin (b) layer 10b are laminated. As long as the thermoplastic resin (b) layer is disposed on the most metal foil layer side, a multilayer structure of three or more layers may be used. Examples of such a multilayer structure include, for example, a four-layer structure of thermoplastic resin (a) layer / thermoplastic resin (b) layer / thermoplastic resin (a) layer / thermoplastic resin (b) layer. When a plurality of thermoplastic resin (a) layers or thermoplastic resin (b) layers are included, the thermoplastic resin (a) or thermoplastic resin constituting the plurality of thermoplastic resin (a) layers or thermoplastic resin (b) layers (B) may be the same or different.

The packaging material of the present invention has excellent moldability by using a biaxially stretched film obtained by co-extrusion of a specific thermoplastic resin (a) and a thermoplastic resin (b) as a base material layer. .
For example, according to the present invention, a drawing depth that can be cold-formed without the occurrence of cracks or pinholes, a configuration in which a base layer and a metal foil layer such as an aluminum foil are conventionally laminated by a dry lamination method It is possible to make it deeper than.

The exterior material of this invention is used for manufacture of a lithium ion battery.
In FIG. 3, an example of the lithium ion battery manufactured using the exterior material of this invention is shown. However, the lithium ion battery manufactured using the exterior material of the present invention is not limited to this.
The lithium ion battery 100 of this example includes a sealed container body 110 formed by the exterior material 1 and a battery member 112 accommodated in the container body 110 so that a part of the tab 114 is exposed to the outside. Have.
The description of the exterior material 1 is as described above.

The container body 110 is formed by folding the rectangular exterior material 1 in two with the sealant layer 18 inside, and includes a first container part 110a, a second container part 110b, and a folded part 110c.
The first container portion 110a is provided with a recess 116 protruding from the sealant layer 18 side to the base material layer 10 side by deep drawing.
The tip edge portion 118 where the sealant layers 18 located on the opposite sides of the folded portion 110c in the first container portion 110a and the second container portion 110b are in contact with each other is heat-sealed with a part of the tab 114 sandwiched therebetween. Yes. In addition, each side edge portion (first side edge portion 120, second side edge portion 122) on both sides of the recess 116 is also heat-sealed.
The container body 110 is sealed by heat-sealing the front edge portion 118 and both side edge portions 120 and 122 in this way. Further, the container body 110 is sealed in a state where the electrolytic solution is housed together with the battery member 112 in the recess 116.

The battery member 112 includes a battery member main body portion 124 having a positive electrode, a separator, and a negative electrode, and tabs 114 and 114 connected to the positive electrode and the negative electrode of the battery member main body portion 124, respectively.
The battery member main body 124 is not particularly limited as long as it is normally used for a lithium ion battery, and examples thereof include a laminate in which a positive electrode, a separator, a negative electrode, and a separator are laminated in this order. As the positive electrode, the negative electrode, and the separator, those usually used for lithium ion batteries can be used without particular limitation.
The tabs 114, 114 have leads 126, 126 joined to the positive electrode and the negative electrode, respectively, and tab sealants 128, 128 wound around the leads 126, 126 and welded to the sealant layer 18 of the tip edge portion 118. The tabs 114 and 114 are installed such that the base end side of the lead 126 is joined to the positive electrode and the negative electrode, respectively, and the tip end side is exposed to the outside of the container body 110.
Examples of the material of the lead 126 include aluminum, nickel, nickel-plated copper, and the like.
The material of the tab sealant 128 may be any material that can be welded to the sealant layer 18 of the exterior material 1, and examples thereof include the same material as the material of the sealant layer 18.

The lithium ion battery 100 can be manufactured using a known method.
Below, an example of the manufacturing method of the lithium ion battery 100 is demonstrated based on FIG. In addition, the manufacturing method of the lithium ion battery 100 is not limited to the following method.
As a manufacturing method of the lithium ion battery 100, the method which has the following process (Y1)-(Y4) is mentioned, for example.
(Y1) The process of forming the recessed part 116 by cold forming in the part used as the 1st container part 110a in the rectangular-shaped exterior material 1. FIG.
(Y2) The battery member main body 124 is disposed in the concave portion 116 of the first container portion 110a, the portion that becomes the second container portion 110b of the exterior material 1 is folded, and the tip edge portion 118 on the opposite side to the folded portion 110c is tabbed. Heat sealing so that a part of 114 is exposed to the outside.
(Y3) A step of heat-sealing the first side edge portion 120.
(Y4) A step of heat-sealing the second side edge portion 122 in a vacuum state after injecting the electrolyte into the recess 116 from the opening on the second side edge portion 122 side.

In the step (Y1), the recess 116 is deep-drawn with a mold so as to have a desired drawing depth in consideration of the rebound amount, for example, from the sealant layer 18 side of the exterior material 1 to the base material layer 10 side. Can be formed.
As the mold, those usually used for deep drawing can be used, and examples thereof include a mold composed of a female mold and a male mold having a gap equal to or larger than the total thickness of the exterior material 1. At the time of deep drawing, for example, by using a lubricant or the like to reduce the friction coefficient of the surface of the exterior material 1, the friction between the mold and the exterior material 1 is reduced, and the mold is pressed from the film presser to the molded part. The exterior material 1 becomes easy to flow. Thereby, the deeper recessed part 116 can be formed, without producing a crack and a pinhole.

In the step (Y2), the battery member main body portion 124 is accommodated in the recess 116 formed in the step (Y1), the portion that becomes the second container portion 110b of the exterior material 1 is folded back, and the leading edge on the opposite side of the folded portion 110c The portion 118 is heat-sealed so that a portion of the portion 118 is exposed outside the tab 114. At this time, the tab sealant 128 of the tab 114 is welded to both the sealant layer 18 on the first container part 110 a side and the sealant layer 18 on the second container part 110 b side in the exterior material 1.
Heat sealing can be controlled by adjusting three conditions: the temperature of the heat seal bar, the surface pressure during sealing, and the sealing time. The temperature of the heat seal bar is a temperature equal to or higher than the melting point of the sealant layer 18 of the exterior material 1, preferably 160 to 210 ° C., and more preferably 170 to 200 ° C. The surface pressure at the time of sealing may be a condition that does not form a molten resin reservoir called a polysphere on the side end surface of the tip edge portion 118, and is preferably 0.01 to 2 MPa, more preferably 0.1 to 1 MPa. . The sealing time varies depending on the temperature of the heat seal bar and the surface pressure during sealing, but is preferably 0.5 to 20 seconds, and more preferably 1 to 10 seconds.
The heat sealing in the steps (Y3) and (Y4) can be performed in the same manner.

The lithium ion battery 100 is obtained by the steps (Y1) to (Y4) described above.
In addition, the manufacturing method of the lithium ion battery 100 is not limited to the method of implementing the said process (Y1)-(Y4) sequentially. For example, the step (Y1) may be performed after the step (Y2) is performed.

EXAMPLES Hereinafter, although an Example demonstrates this invention in detail, this invention is not limited by the following description.
<Materials used>
The materials (materials used for forming each layer) used in this example are shown below.

[Base material layer]
Film A-1: A biaxially stretched film in which the thermoplastic resin (a) layer and the thermoplastic resin (b) layer shown in Table 1 are laminated.
Film A-2: A biaxially stretched film in which the thermoplastic resin (a) layer and the thermoplastic resin (b) layer shown in Table 1 are laminated.
The abbreviations in Table 1 have the following meanings.
PET: Polyethylene terephthalate.
b-1: Polyester elastomer graft-modified with maleic anhydride.
Ny-6: Nylon 6.

Films A-1 to A-2 were produced by the following procedure.
The thermoplastic resin (a) and the thermoplastic resin (b) are formed into a film by co-extrusion, and the formed molten resin is quenched at 20 ° C. on a rotating cooling drum by the T-die method. A pressed film was obtained. Then, using a roller-type longitudinal stretching machine composed of heating roller groups having different peripheral speeds, a stretching roll for heating the obtained co-pressed film to a temperature higher than the glass transition point of the thermoplastic resin (a), and film cooling The film was stretched longitudinally between the cooling rolls. Furthermore, the film after longitudinal stretching was guided to a tender and laterally stretched at a temperature equal to or higher than the glass transition point of the thermoplastic resin (a) to obtain a biaxially stretched film (film A-1 or A-2).

Film A′-1: Biaxially stretched PET film.
Film A′-2: Biaxially stretched nylon (Ny) film.
In addition, film A'-1 and A'-2 were used as a comparison object, and were laminated | stacked with metal foil through the outer side adhesion layer (5 micrometers).

[Outside adhesive layer]
Adhesive B-1: polyurethane adhesive.

[Metal foil layer]
Metal foil C-1: Soft aluminum foil 8079 material.

[Corrosion prevention treatment layer, adhesion improvement treatment layer]
Treatment agent D-1: Treatment agent prepared by blending 10 parts by mass of Na salt of phosphoric acid with 100 parts by mass of cerium oxide and adjusting the solid content concentration to 10% by mass using distilled water as a solvent.
Treatment agent D-2: A composition prepared by adjusting a mixture of 90% by mass of a polyacrylic acid polymer and 10% by mass of an oxazoline compound to a solid content concentration of 5% by mass using distilled water as a solvent.
Treatment agent D-3: A composition prepared by adjusting a mixture of 90% by mass of a polyallylamine polymer and 10% by mass of a glycidyl compound to a solid content concentration of 5% by mass using distilled water as a solvent.

[Inner adhesive layer]
Adhesive component E-1: An acid-modified polyolefin resin in which an elastomer made of an ethylene-α-olefin copolymer is blended with a modified PP obtained by graft-modifying maleic anhydride on random polypropylene.
Adhesive component E-2: An adhesive composition in which 10% by mass of a polyisocyanate compound is blended with 100 parts by mass of maleic anhydride-modified polyolefin resin dissolved in toluene.
In forming the inner adhesive layer 17, the adhesive E-2 was applied at a dry application amount of 4 to 5 g / m ² .

[Sealant layer]
Film F-1: 2-layer, 3-layer multilayer film (thickness: 60 μm) made of random propylene / block propylene / random propylene.

<Examples 1-6>
[Production of exterior materials]
On one surface of the metal foil C-1 to be a metal foil layer, the treatment agent D-1 is applied and dried, and then the treatment agent D-3 is applied and dried to form an adhesion improving treatment layer. A metal foil having an adhesion improving treatment layer on one side (hereinafter referred to as “metal foil C-2”) was obtained.
Separately, the treatment agent D-1 is applied to one surface of the metal foil C-1 and dried, and then the treatment agent D-2 is applied and dried to form an adhesion improving treatment layer, which is adhered to one surface. A metal foil having an improved treatment layer (hereinafter referred to as “metal foil C-3”) was obtained.
In the formation of the adhesion improving treatment layer, the treatment agent was applied by microgravure coating. The coating amount was 10 to 200 mg / m ² as the final dry coating amount (total dry coating amount of all treatment agents). Drying (baking treatment) after coating was performed at 150 to 250 ° C. according to the type of each of the processing agents D-1 to D-3 in the drying unit.

The treatment agent D-1 is applied to one surface of the metal foil C-1, C-2 or C-3 (the surface where the adhesion improving treatment layer is not provided for C-2 and C-3). Then, the treatment agent D-3 was applied and dried to form a corrosion prevention treatment layer.
In the formation of the corrosion prevention treatment layer, the treatment agent was applied by microgravure coating. The coating amount was 70 to 100 mg / m ² as the final dry coating amount. Drying (baking treatment) after coating was performed at 150 to 250 ° C. in the drying unit depending on the types of the treating agents D-1 and D-3.

Next, the surface of the metal foil C-1, C-2, or C-3 on the side opposite to the side on which the corrosion prevention treatment layer is formed, and the film A-1 or A-2 on the thermoplastic resin (b) side. The surface was brought into close contact by coextrusion. Thereby, the laminated body of the layer structure of a base material (/ adhesion improvement processing layer) / metal foil layer / corrosion prevention processing layer was obtained.
Next, the adhesive component E-1 is extruded to a thickness of 20 μm at 260 to 300 ° C. by an extrusion laminator on the corrosion prevention treatment layer side of the obtained laminate, and the film F-1 is bonded by sandwich lamination. It was. Thereafter, thermocompression bonding was performed at 160 ° C., 4 kg / cm ² , and 2 m / min. As a result, an exterior material having a layer structure of base material (/ adhesion improving treatment layer) / metal foil layer / corrosion prevention treatment layer / inner adhesion layer / sealant layer was obtained.
About the obtained exterior material, the moldability was evaluated in the following procedures. The results are shown in Table 2.

[Evaluation of moldability]
The obtained exterior material was cut into a blank shape of 150 mm × 190 mm, and a concave portion was formed by cold forming at the center. A punch having a shape of 100 mm × 150 mm, a punch corner R (RCP) of 1.5 mm, a punch shoulder R (RP) of 0.75 mm, and a die shoulder R (RD) of 0.75 mm was used. The mold closing pressure (air cylinder) was 0.5 to 0.8 MPa, and the stroke speed was 5 mm / second. R represents the radius of curvature.
In the formation of the concave portion, the drawing depth was increased from 4 mm to 1 mm, and cold forming with the same drawing depth was performed 10 times to prepare a sample for evaluation. Each sample was checked for pinholes and fractures, and the moldability was evaluated according to the following evaluation criteria.
○: Cold forming with a drawing depth of 8 mm or more is possible without causing pinholes or breakage.
Δ: Cold forming with a drawing depth of 5 mm or more and less than 8 mm is possible without causing pinholes or breakage.
X: Cold forming exceeding a drawing depth of 5 mm cannot be performed without causing pinholes or breakage.
Further, the drawing depth (maximum drawing depth) of the sample having the deepest drawing depth among the samples in which no pinhole or breakage occurred was obtained.
However, in Examples 1 to 6 and Examples 7 to 12 and Comparative Examples 1 to 12 below, the evaluation results of the moldability of 10 samples were the same.

<Examples 7 to 12>
The steps until obtaining a laminate having a layer structure of substrate (/ adhesion improving treatment layer) / metal foil layer / corrosion prevention treatment layer were performed in the same manner as in Examples 1-6.
Next, the adhesive component E-2 was applied by a gravure reverse coat at a dry coating amount of 4 to 5 g / m ² on the corrosion prevention treatment layer side of the laminate, and the film F-1 was bonded by a dry laminating method. . Thereafter, aging was performed at 60 ° C. for 6 days. As a result, an exterior material having a layer structure of base material (/ adhesion improving treatment layer) / metal foil layer / corrosion prevention treatment layer / inner adhesion layer / sealant layer was obtained.
About the obtained exterior material, the moldability was evaluated similarly to Examples 1-6. The results are shown in Table 2.

<Comparative Examples 1-6>
A treatment agent D-1 is applied to one surface of the metal foil C-1, C-2 or C-3 (the surface where the adhesion improving treatment layer is not provided for C-2 and C-3). Then, the treatment agent D-2 was applied and dried to form a corrosion prevention treatment layer.
In the formation of the corrosion prevention treatment layer, the treatment agent was applied by microgravure coating. The coating amount was 70 to 100 mg / m ² as the final dry coating amount. Drying (baking treatment) after coating was performed at 150 to 250 ° C. according to the type of each of the processing agents D-1 and D-2 in the drying unit.

Next, on the opposite side of the metal foil C-1, C-2 or C-3 from the side on which the anticorrosion treatment layer was formed, the adhesive B-1 was applied in a dry coating amount of 4 to 5 g / g by gravure reverse coating. It applied in m ^2, and bonded to the film B-1 or B-2 by a dry lamination method. Thereafter, aging was performed at 60 ° C. for 6 days. Thereby, the laminated body of the layer structure of a base material / outer side adhesion layer (/ adhesion improvement processing layer) / metal foil layer / corrosion prevention processing layer was obtained.
Next, the film F-1 was bonded to the corrosion prevention treatment layer side of the obtained laminate by sandwich lamination in the same manner as in Examples 1-6. As a result, an exterior material having a layer configuration of base material / outer adhesive layer (/ adhesion improving treatment layer) / metal foil layer / corrosion prevention treatment layer / inner adhesion layer / sealant layer was obtained.
About the obtained exterior material, the moldability was evaluated similarly to Examples 1-6. The results are shown in Table 2.

<Comparative Examples 7-12>
The steps until obtaining a laminate having a layer structure of base material / outer adhesive layer (/ adhesion improving treatment layer) / metal foil layer / corrosion prevention treatment layer were carried out in the same manner as in Comparative Examples 1-6.
Next, the film F-1 was bonded to the corrosion prevention treatment layer side of the laminate by the dry lamination method in the same manner as in Examples 1-6. Thereafter, aging was performed at 60 ° C. for 6 days. As a result, an exterior material having a layer configuration of base material / outer adhesive layer (/ adhesion improving treatment layer) / metal foil layer / corrosion prevention treatment layer / inner adhesion layer / sealant layer was obtained.
About the obtained exterior material, the moldability was evaluated similarly to Examples 1-6. The results are shown in Table 2.

When Example 1 and Comparative Example 1 are compared, the biaxially stretched film formed by coextrusion of the thermoplastic resin (a) and the thermoplastic resin (b) and the metal foil are directly or directly provided with an adhesion improving treatment layer. Thus, the exterior material of Example 1 laminated by heat treatment was compared with the exterior material of Comparative Example 1 having the same configuration except that a film corresponding to the thermoplastic resin (a) layer and a metal foil were laminated by a dry lamination method. Formability (drawing depth that can be cold-formed without causing pinholes or breakage) has been improved. Similar results were confirmed when Examples 2 to 12 were compared with corresponding Comparative Examples 2 to 12, respectively.
Among Examples 1 to 12, Examples 1, 4, 7, and 10 in which the adhesion improving treatment layer was not provided, and Examples 2-3, 5 to 6, 8 to 9, 11 in which the adhesion improving treatment layer was provided. From the comparison with No. 12, it was confirmed that by providing the adhesion improving treatment layer, the moldability was improved more than without the adhesion improving treatment layer.

  The outer packaging material for a lithium ion battery of the present invention can be suitably used for applications requiring long-term reliability and safety because it can be cold-formed at a deep drawing depth without generating cracks or pinholes. In particular, it is effective for an application that needs to extract a large current, such as an electric vehicle.

DESCRIPTION OF SYMBOLS 1 Exterior material for lithium ion batteries 2 Exterior material for lithium ion batteries 10 Base material layer 10a Thermoplastic resin (a) layer 10b Thermoplastic resin (b) layer 15 Metal foil layer 16 Corrosion prevention treatment layer 17 Inner adhesive layer 18 Sealant layer 19 Adhesion improving treatment layer 100 Lithium ion battery 110 Container body 112 Battery member 114 Tab 116 Recess 118 Front edge portion 120 First side edge portion 122 Second side edge portion

Claims (4)

At least a metal foil layer, an inner adhesive layer, and a sealant layer are laminated in this order on one surface side of the base material layer, and a corrosion prevention treatment layer is provided on the adhesive layer side surface of the metal foil layer. A lithium-ion battery exterior material,
The base material layer is composed of a biaxially stretched film obtained by coextrusion of the following thermoplastic resin (a) and the following thermoplastic resin (b),
A packaging material for a lithium ion battery, wherein the layer of the thermoplastic resin (b) is disposed closest to the metal foil layer in the base material layer, and the layer and the metal foil layer are in contact with each other.
Thermoplastic resin (a): aromatic polyester resin or polyamide resin.
Thermoplastic resin (b): Modified thermoplastic graft-modified with at least one unsaturated carboxylic acid derivative selected from the group consisting of unsaturated carboxylic acids, unsaturated carboxylic acid anhydrides, and unsaturated carboxylic acid esters resin. At least a metal foil layer, an inner adhesive layer, and a sealant layer are laminated in this order on one surface side of the base material layer, and an adhesion improving treatment layer is provided on the base material side surface of the metal foil layer. , A lithium ion battery exterior material provided with a corrosion prevention treatment layer on the surface of the metal foil layer on the adhesive layer side,
The base material layer is composed of a biaxially stretched film obtained by coextrusion of the following thermoplastic resin (a) and the following thermoplastic resin (b),
The outer layer material for a lithium ion battery, wherein the thermoplastic resin (b) layer is disposed closest to the metal foil layer in the base material layer, and the layer and the adhesion improving treatment layer are in contact with each other. .
Thermoplastic resin (a): aromatic polyester resin or polyamide resin.
Thermoplastic resin (b): Modified thermoplastic graft-modified with at least one unsaturated carboxylic acid derivative selected from the group consisting of unsaturated carboxylic acids, unsaturated carboxylic acid anhydrides, and unsaturated carboxylic acid esters resin.   In the said base material layer, the thickness of the layer of the said thermoplastic resin (a) is 1 micrometer or more and 50 micrometers or less, The thickness of the layer of the said thermoplastic resin layer (b) is 0.1 micrometer or more and 5 micrometers or less. Or an outer packaging material for a lithium ion battery according to 2; The exterior material for a lithium ion battery according to claim 2 , wherein the base material layer and the metal foil layer or the adhesion improving treatment layer are adhered by heat treatment.

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