JP6519209B2 - Storage material for power storage device - Google Patents

Description

  The present invention relates to an exterior material for a power storage device.

  As a power storage device, for example, secondary batteries such as lithium ion batteries, nickel hydrogen batteries, and lead storage batteries, and electrochemical capacitors such as electric double layer capacitors are known. Further miniaturization of the power storage device is required due to miniaturization of portable equipment or limitation of installation space, etc., and a lithium ion battery with high energy density is attracting attention. Conventionally, metal cans have been used as exterior materials used for lithium ion batteries, but multilayer films that are lightweight, have high heat dissipation, and can be manufactured at low cost (for example, base layer / metal foil layer / A configuration such as a sealant layer is to be used.

  In the lithium ion battery using the above multilayer film as the packaging material, in order to prevent the entry of moisture into the inside, a configuration is used in which the battery contents are covered with the packaging material including the aluminum foil layer as the metal foil layer. A lithium ion battery adopting such a configuration is called an aluminum laminate type lithium ion battery. In the battery contents of the lithium ion battery, lithium salt as electrolyte is added to the positive electrode, negative electrode and separator together with a penetrant aprotic solvent such as propylene carbonate, ethylene carbonate, dimethyl carbonate, diethyl carbonate, ethyl methyl carbonate etc. It includes an electrolyte layer made of a dissolved electrolyte or a polymer gel impregnated with the electrolyte.

  In the aluminum laminate type lithium ion battery, for example, a recess is formed by cold molding in a part of the outer package, the battery contents are accommodated in the recess, the remaining part of the outer package is folded, and the edge is heated An embossed type lithium ion battery sealed with a seal is known. It is required that the packaging material constituting such a lithium ion battery exhibits stable sealing performance by heat sealing, and that the reduction in the laminate strength between the aluminum foil layer and the sealant layer is unlikely to occur by the electrolyte solution of the battery contents. ing.

  Moreover, the energy density of a lithium ion battery can be made high, so that the recessed part formed by cold molding is made deep. However, as the recess is made deeper, fine cracks are more likely to be generated in the sealant layer due to distortion generated at the time of cold forming, and the whitening phenomenon of the sealant layer is more likely to occur particularly in the squeezed portions such as molded side portions and corner portions. Since the whitening phenomenon in cold forming brings about the insulation fall and promotes the deterioration of the battery performance, it is required to suppress the whitening due to the bending as well as the whitening phenomenon due to the crack.

  Therefore, for example, Patent Document 1 discloses a heat seal comprising a high melting point polypropylene layer having a melting point of 150 ° C. or more and a propylene-ethylene random copolymer layer as an exterior material exhibiting stable sealing performance, heat resistance, insulation properties and moldability. An exterior material provided with a layer (a sealant layer) has been proposed.

JP 2007-273398 A

  However, in the case of the conventional exterior material as described in Patent Document 1 above, although studies have been made on the improvement of the sealing property, the improvement of the insulation property, and the heat resistance of the sealing portion, the most severe in the manufacturing process of the storage device. No study has been made on the improvement of the degassing seal (seal performed with the electrolyte inserted). In the degashing seal, since heat sealing is performed while inserting the above-described electrolytic solution, the heat amount at the time of sealing is taken away by the electrolytic solution, and sealing failure easily occurs. On the other hand, while there is a demand for improvement in tact time of power storage device manufacture, stable sealability (degassing heat seal strength) in the degashing sealing process where the heat quantity of sealing is most required is required. . In addition, if the heat sealability at a low temperature is too high in order to improve the sealability in the degashing sealing process, thermal fusion (excessive seal portion) occurs outside the seal portion, causing the sealing resistance and the storage device to There is a problem that internal volume reduction occurs.

  The present invention has been made in view of the problems of the above-mentioned prior art, and suppresses the occurrence of an excessive seal portion and the occurrence of mold whitening, and at the same time, the seal characteristics involving the electrolyte including the degashing heat seal strength. An object of the present invention is to provide an exterior material for a power storage device that can be improved.

  In order to achieve the above object, the present invention relates to at least a substrate layer, a first adhesive layer, a metal foil layer provided with a corrosion prevention treatment layer on one or both surfaces, a second adhesive layer or an adhesive Conductive resin layer and an exterior material for a power storage device having a structure in which a sealant layer is laminated in this order, and the sealant layer comprises 60 to 95% by mass of (A) a propylene-ethylene random copolymer, (B) A packaging material for a storage battery, which is a layer formed of a resin composition containing 5 to 40% by mass of a polyolefin-based elastomer having a melting point of 150 ° C. or less containing butene-1 as a comonomer.

  According to such an exterior material for a storage battery, by providing the sealant layer having the above-described configuration, the seal characteristics involving the electrolyte including the degashing heat seal strength while suppressing the occurrence of the excessive seal portion and the occurrence of mold whitening. Can be improved. That is, although the (A) propylene-ethylene random copolymer (hereinafter also referred to as "component (A)") has low crystallinity and good heat sealability, (B) butene-1 as a comonomer is further used. By blending a polyolefin-based elastomer having a melting point of 150 ° C. or less (hereinafter, also referred to as “component (B)”), the sealing property at low heat amount can be appropriately enhanced, and sealing properties involving the electrolyte, particularly, Degassing heat seal strength can be improved. At this time, when the content of the component (B) is less than 5% by mass, the improvement of the degashing heat seal strength is particularly insufficient, and when it exceeds 40% by mass, the amount of the elastomer component is excessive. The heat resistance is lowered, and the heat sealability at a low temperature is too high, so that the excessive seal portion is increased, and the processability is also lowered at the time of processing. Therefore, by setting the content of the component (A) and the component (B) in the above range, the sealing characteristics involving the electrolytic solution including the degashing heat seal strength is improved while suppressing the occurrence of the excessive sealing portion. be able to. In addition, when component (B) contains butene-1 as a comonomer, good affinity with component (A) can be obtained, and cold as compared with the case where an elastomer containing no butene-1 is used. The occurrence of cracks during molding is suppressed and the whitening phenomenon is reduced.

  Further, the storage battery packaging material of the present invention can stabilize the degashing heat seal strength, thereby making it possible to suppress the influence of the heat quantity at the time of sealing, thereby shortening the tact time of the storage battery production. It becomes possible.

  In the above packaging material for a power storage device, the (B) compatible polyolefin-based elastomer in which the (B) polyolefin-based elastomer has compatibility with the (A) propylene-ethylene random copolymer, and the (A) It is preferable to include (B-2) incompatible polyolefin-based elastomer which is not compatible with the propylene-ethylene random copolymer.

  (B-1) The compatible polyolefin-based elastomer can impart further low-temperature sealability and resistance to mold whitening, and further improves seal characteristics involving an electrolytic solution such as degashing heat seal strength. It can be done. On the other hand, the (B-2) immiscible polyolefin-based elastomer can further improve the sealing characteristics involving the electrolytic solution such as the degumming heat seal strength by the effect of stress relaxation. By using the two compatible polyolefin elastomers of the compatible system and the incompatible system in combination, it is possible to improve the whitening resistance against molding and the seal characteristics related to the electrolyte in a well-balanced manner.

  Here, the (B-1) compatible polyolefin-based elastomer is a propylene-butene-1 random copolymer, and the (B-2) incompatible polyolefin-based elastomer is an ethylene-butene-1 random copolymer. It is preferable to be combined. Since the affinity between the component (A), the propylene-butene-1 random copolymer and the ethylene-butene-1 random copolymer is good, the above-described molding whitening resistance and the sealing characteristics involving the electrolyte are further enhanced. It can be improved in a well-balanced manner. In addition, for example, in the case of using an incompatible elastomer not containing butene-1 such as ethylene-propylene elastomer (in which polyethylene glycol (70 to 80% by mass is finely dispersed olefin rubber, etc.)), a sealant layer is used A clear sea-island structure is formed inside, and a crack (void-claze) is easily generated at the interface of the sea-island structure due to stress at the time of molding, and it tends to be accompanied by whitening. On the other hand, when an incompatible elastomer containing butene-1 such as ethylene-butene-1 random copolymer is used, the sea surface adhesion in the sea-island structure can be improved, and stress such as molding is applied. However, the occurrence of whitening is reduced.

  In the storage material for a storage battery, the metal foil layer and the sealant layer are laminated via the adhesive resin layer, and the adhesive resin layer contains modified polypropylene as an adhesive resin composition. preferable. When the modified polyolefin resin forming the adhesive resin contains the modified polypropylene, the (B) polyolefin elastomer having butene-1 as a comonomer can obtain affinity with the modified polypropylene forming the adhesive resin, and as a result, The occurrence of cracks between the adhesive resin layer and the sealant layer is further suppressed, and a higher effect of suppressing the decrease in seal strength and the occurrence of whitening can be obtained.

  In the storage material for an electric storage device, the metal foil layer and the sealant layer are laminated via the adhesive resin layer, and the adhesive resin layer is composed of an adhesive resin composition and an atactic structure. It may contain polypropylene or a propylene-α-olefin copolymer having an atactic structure. In this case, whitening due to molding can be alleviated.

  Here, the adhesive resin layer preferably further includes a propylene-α-olefin copolymer having an isotactic structure. In this case, flexibility for relieving stress can be imparted to the adhesive resin layer, so improvement in heat seal strength (particularly, electrolyte resistance) and deterioration seal strength can be achieved while suppressing a decrease in electrolytic solution laminate strength. Improvement is possible. Moreover, the whitening phenomenon and bending-proof insulation property can be further improved by combining with the polypropylene of the atactic structure mentioned above, or the propylene-alpha olefin copolymer of an atactic structure.

  In the storage material for a storage battery, the corrosion prevention treatment layer is provided at least on the sealant layer side of the metal foil layer, and the corrosion prevention treatment layer is selected from the group consisting of a cationic polymer and an anionic polymer. And the metal foil layer and the sealant layer are laminated via the second adhesive layer, and the second adhesive layer is the second adhesive layer. It may contain a compound having reactivity with the above-mentioned polymer contained in the above-mentioned corrosion prevention treatment layer in contact with. In this case, the adhesion between the corrosion prevention treatment layer and the second adhesive layer is improved by the firm bonding between the polymer in the corrosion prevention treatment layer and the compound in the second adhesive layer, and lamination is performed. Strength is improved.

  In the storage material for an electric storage device, when the corrosion prevention treatment layer contains the polymer and the second adhesive layer contains a compound having reactivity with the polymer, the second adhesive layer is acid-modified It may contain a polyolefin resin. In this case, the adhesion between the second adhesive layer and the corrosion prevention treatment layer is further enhanced, and the solvent resistance of the second adhesive layer is further enhanced.

  In the storage material for a storage battery, the corrosion prevention treatment layer contains a rare earth element oxide and 1 to 100 parts by mass of phosphoric acid or phosphate based on 100 parts by mass of the rare earth element oxide. It may be.

  According to the present invention, it is possible to provide an outer covering material for a storage battery capable of improving the sealing characteristics involving the electrolytic solution including the degashing heat sealing strength while suppressing the occurrence of the excessive sealing portion and the occurrence of molding whitening. be able to.

FIG. 1 is a schematic cross-sectional view of an exterior material for a power storage device according to an embodiment of the present invention. It is a schematic sectional drawing of the exterior material for electrical storage devices which concerns on other one Embodiment of this invention. It is a schematic diagram explaining the preparation methods of the evaluation sample in an Example. It is a schematic diagram explaining the preparation methods of the evaluation sample in an Example.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals, and overlapping descriptions will be omitted. Further, the dimensional ratio in the drawings is not limited to the illustrated ratio.

[Exterior material for power storage device]
FIG. 1 is a cross-sectional view schematically showing an embodiment of a packaging material for a power storage device of the present invention. As shown in FIG. 1, the exterior material (exterior material for a power storage device) 10 of the present embodiment includes a base material layer 11 and a first adhesive layer 12 formed on one surface of the base material layer 11. And the metal foil layer 13 formed on the surface of the first adhesive layer 12 opposite to the substrate layer 11, and the surface of the metal foil layer 13 opposite to the first adhesive layer 12 , An adhesive resin layer 15 formed on the surface of the anti-corrosion treatment layer 14 opposite to the metal foil layer 13, and an anti-corrosion treatment layer of the adhesive resin layer 15 14 is a laminate in which a sealant layer 16 formed on the surface opposite to 14 is sequentially laminated. In the sheath material 10, the base material layer 11 is the outermost layer, and the sealant layer 16 is the innermost layer. That is, the packaging material 10 is used with the base material layer 11 directed to the outside of the power storage device and the sealant layer 16 directed to the inside of the power storage device. Each layer will be described below.

<Base material layer 11>
The base material layer 11 is provided for the purpose of heat resistance imparting in the sealing step at the time of manufacturing the electric storage device, and for the purpose of countermeasure against pinholes which may occur in processing and distribution. It is preferable to use a resin layer having insulation properties. As such a resin layer, for example, a stretched or unstretched film such as a polyester film, a polyamide film, or a polypropylene film can be used as a multilayer film in which a single layer or two or more layers are laminated. More specifically, after coextrusion of polyethylene terephthalate film (PET) and nylon film (Ny) using an adhesive resin, it is possible to use a co-extruded multilayer stretched film subjected to a stretching process.

  6-40 micrometers is preferable and, as for the thickness of the base material layer 11, 10-25 micrometers is more preferable. When the thickness of the base material layer 11 is less than 6 μm, there is a tendency that the pinhole resistance and the insulation property of the packaging material 10 for a power storage device can be improved. On the other hand, when the thickness of the base material layer 11 is 40 μm or less, there is a tendency that the deep drawability of the power storage device packaging material 10 can be further improved.

<First adhesive layer 12>
The first adhesive layer 12 is a layer for bonding the base layer 11 and the metal foil layer 13. Specifically, as a material constituting the first adhesive layer 12, specifically, for example, a polyurethane obtained by reacting a main compound such as polyester polyol, polyether polyol, acrylic polyol, or carbonate polyol with a bifunctional or higher isocyanate compound. Resin etc. are mentioned.

  Polyester polyols are aliphatic such as succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, brassic acid; aromatic dibasics such as isophthalic acid, terephthalic acid and naphthalene dicarboxylic acid Aliphatic acid such as ethylene glycol, propylene glycol, butanediol, neopentyl glycol, methylpentanediol, hexanediol, heptanediol, octanediol, nonanediol, decanediol, dodecanediol, etc .; cyclohexanediol, hydrogenated It is obtained using an alicyclic system such as xylylene glycol; and one or more aromatic diols such as xylylene glycol.

  Moreover, as the polyester polyol, for example, 2,4- or 2,6-tolylene diisocyanate, xylylene diisocyanate, the hydroxyl groups at both ends of the polyester polyol obtained by using the dibasic acid and the diol described above, 4, 4'-diphenylmethane diisocyanate, methylene diisocyanate, isopropylene diisocyanate, lysine diisocyanate, 2,2,4- or 2,4, 4-trimethylhexamethylene diisocyanate, 1,6-hexamethylene diisocyanate, methylcyclohexane diisocyanate, isophorone diisocyanate, 4 A single isocyanate compound selected from 4,4'-dicyclohexylmethane diisocyanate, isopropylidene dicyclohexyl-4,4'-diisocyanate, etc. Or adducts formed of the above isocyanate compounds selected from at least one or more, biuret body, such as a polyester urethane polyol chain extension with isocyanurate products thereof.

  As the polyether polyol, it is possible to use an ether-based polyol such as polyethylene glycol or polypropylene glycol, or a polyether urethane polyol treated with the above-mentioned isocyanate compound as a chain extender.

  As an acrylic polyol, it is possible to use the acrylic resin polymerized using the acrylic type monomer mentioned above.

  The carbonate polyol can be obtained by reacting a carbonate compound with a diol. As a carbonate compound, dimethyl carbonate, diphenyl carbonate, ethylene carbonate and the like can be used. On the other hand, as diols, aliphatic diols such as ethylene glycol, propylene glycol, butanediol, neopentyl glycol, methylpentanediol, hexanediol, heptanediol, octanediol, nonanediol, decanediol, dodecanediol, etc .; cyclohexanediol, water Alicyclic diols such as additive xylylene reels; carbonate polyols using a mixture of one or more kinds of aromatic diols such as xylylene reels; and polycarbonate urethane polyols which have been chain-extended by the above-mentioned isocyanate compound.

  The various polyols mentioned above can be used individually or in combination of 2 or more types according to the function and performance which are calculated | required by the exterior material. Moreover, it is also possible to use as a polyurethane type adhesive agent by using the isocyanate type compound mentioned above as a hardening | curing agent for these main ingredients.

  Furthermore, for the purpose of promoting adhesion, a carbodiimide compound, an oxazoline compound, an epoxy compound, a phosphorus compound, a silane coupling agent, or the like may be added to the above-described polyurethane resin.

  As the carbodiimide compound, for example, 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-cyclohexyl carbodiimide, N, N'-di-p-toluyl carbodiimide etc. And the like.

  Examples of oxazoline compounds 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 Compounds, 2,2 '-(1,3-phenylene) -bis (2-oxazoline), 2,2'-(1,2-ethylene) -bis (2-oxazoline), 2,2 '-(1,1) Examples include dioxazoline compounds such as 4-butylene) -bis (2-oxazoline) and 2,2 '-(1,4-phenylene) -bis (2-oxazoline).

  As an epoxy compound, for example, 1,6-hexanediol, neopentyl glycol, diglycidyl ether of aliphatic diol such as polyalkylene glycol, sorbitol, sorbitan, polyglycerol, pentaerythritol, diglycerol, glycerol, trimethylol Polyglycidyl ethers of aliphatic polyols such as propane, polyglycidyl ethers of alicyclic polyols such as cyclohexanedimethanol, terephthalic acid, isophthalic acid, naphthalenedicarboxylic acid, trimellitic acid, adipic acid, sebacic acid, etc. aliphatic, aromatic Ester or polyglycidyl ester of polyvalent carboxylic acid of the above group, resorcinol, bis- (p-hydroxyphenyl) methane, 2,2-bis- (p-hydroxyphenyl) Diglycidyl ether or polyglycidyl ether of polyhydric phenol such as propane, tris- (p-hydroxyphenyl) methane, 1,1,2,2-tetrakis (p-hydroxyphenyl) ethane, N, N'-diglycidyl aniline N, N, N-diglycidyl toluidine, N, N, N ', N'-tetraglycidyl-bis- (p-aminophenyl) methane like N-glycidyl derivative of amine, trifglycidyl derivative of aminophor, Examples thereof include triglycidyl tris (2-hydroxyethyl) isocyanurate, triglycidyl isocyanurate, ortho-cresol epoxy, and phenol novolac epoxy.

  As a phosphorus compound, for example, tris (2,4-di-t-butylphenyl) phosphite, tetrakis (2,4-di-t-butylphenyl) 4,4′-biphenylene phosphonite, bis (2) 2,4-di-tert-butylphenyl) pentaerythritol-di-phosphite, bis (2,6-di-tert-butyl-4-methylphenyl) pentaerythritol-di-phosphite, 2,2-methylene bis (4 , 6-di-t-butylphenyl) octyl phosphite, 4,4'-butylidene-bis (3-methyl-6-t-butylphenyl-di-tridecyl) phosphite, 1,1,3-tris (2) -Methyl-4-ditridecylphosphite-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.

  As a silane coupling agent, for example, vinyltriethoxysilane, vinyltris (β-methoxyethoxy) silane, γ-methacryloxypropyltrimethoxysilane, vinyltriacetoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-glyco Cidoxypropyltriethoxysilane, β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, γ-chloropropylmethoxysilane, vinyltrichlorosilane, γ-mercaptopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, N It is possible to use various silane coupling agents such as -β (aminoethyl) -γ-aminopropyltrimethoxysilane.

  In addition, other various additives and stabilizers may be added to the above-described polyurethane resin according to the performance required for the adhesive.

  The thickness of the first adhesive layer 12 is not particularly limited, but it is preferably, for example, 1 to 10 μm, and 3 to 7 μm from the viewpoint of obtaining desired adhesive strength, followability, processability and the like. More preferable.

<Metal foil layer 13>
Metal foil layer 13 has a water vapor barrier property that prevents moisture from entering the inside of the power storage device. In addition, the metal foil layer 13 has spreadability for deep drawing. As the metal foil layer 13, various metal foils such as aluminum and stainless steel can be used, and in view of mass (specific gravity), moisture resistance, processability and cost, an aluminum foil is preferable.

  As the aluminum foil, a general soft aluminum foil can be used, but it is preferable to use an aluminum foil containing iron for the purpose of imparting further pinhole resistance and spreadability at the time of molding. 0.1-9.0 mass% is preferable in 100 mass% of aluminum foils, as for content of iron in aluminum foil, 0.5-2.0 mass% is more preferable. When the content of iron is 0.1% by mass or more, the exterior material 10 having more excellent pinhole resistance and spreadability can be obtained. When the content of iron is 9.0% by mass or less, the exterior material 10 having more excellent flexibility can be obtained.

  Further, as the aluminum foil, a soft aluminum foil (for example, an aluminum foil composed of an 8021 material and an 8079 material as defined in JIS standard) is more preferable from the viewpoint of being able to impart desired ductility in molding.

  The thickness of the metal foil layer 13 is not particularly limited, but is preferably 9 to 200 μm and more preferably 15 to 100 μm in consideration of barrier property, pinhole resistance, and processability. .

  When an aluminum foil is used for the metal foil layer 13, an untreated aluminum foil may be used as the aluminum foil, but it is preferable to use an aluminum foil which has been subjected to a degreasing treatment in terms of imparting resistance to an electrolytic solution. Degreasing treatment is roughly classified into wet type and dry type.

  Examples of the wet type include acid degreasing and alkaline degreasing. Examples of the acid used for acid degreasing include inorganic acids such as sulfuric acid, nitric acid, hydrochloric acid and hydrofluoric acid, and these inorganic acids may be used alone or in combination of two or more. . Further, from the viewpoint of improving the etching effect of the aluminum foil, various metal salts serving as a supply source of Fe ions, Ce ions, etc. may be blended as needed. Examples of the alkali used for alkaline degreasing include strong etching types such as sodium hydroxide. Moreover, you may use what mixed the weak alkali type | system | group and surfactant. These degreasing is performed by the immersion method or the spray method.

  As a dry type, the method of degreasing processing is mentioned at the process of annealing-processing aluminum. In addition to degreasing treatment, flame treatment, corona treatment or the like may be performed. Another example is a degreasing treatment in which contaminants are oxidized and decomposed / removed by active oxygen generated by irradiating ultraviolet light of a specific wavelength.

  When degreasing the aluminum foil, degreasing may be performed on only one side of the aluminum foil, or both sides may be degreased.

<Corrosion prevention treatment layer 14>
The corrosion prevention treatment layer 14 is a layer provided to prevent the corrosion of the metal foil layer 13 due to the electrolytic solution or the hydrofluoric acid generated by the reaction of the electrolytic solution and water. The corrosion prevention treatment layer 14 is formed, for example, by degreasing treatment, hydrothermal transformation treatment, anodizing treatment, chemical conversion treatment, or a combination of these treatments.

  As the degreasing treatment, acid degreasing or alkaline degreasing may be mentioned. Examples of acid degreasing include a method using an inorganic acid such as sulfuric acid, nitric acid, hydrochloric acid or hydrofluoric acid alone or a mixture thereof. In addition, when using an acid degreasing agent in which a fluorine-containing compound such as monosodium ammonium difluoride is dissolved in the above-mentioned inorganic acid as acid degreasing, particularly when aluminum foil is used for the metal foil layer 13, degreasing of aluminum Not only an effect can be obtained, but also a passive aluminum fluoride can be formed, which is effective in terms of hydrofluoric acid resistance. Examples of alkaline degreasing include methods using sodium hydroxide and the like.

  As a hydrothermal transformation process, the boehmite process which immerses an aluminum foil in the boiling water which added triethanolamine is mentioned, for example.

  Examples of the anodizing treatment include alumite treatment.

  Examples of the chemical conversion treatment include immersion type and coating type. Examples of the immersion type chemical conversion treatment include chromate treatment, zirconium treatment, titanium treatment, vanadium treatment, molybdenum treatment, calcium phosphate treatment, calcium hydroxide treatment, strontium hydroxide treatment, cerium treatment, ruthenium treatment, and various chemical treatment treatments composed of these mixed phases. Be On the other hand, as a coating type chemical conversion treatment, the method of coating the coating agent which has corrosion prevention performance on the metal foil layer 13 is mentioned.

  In the case of forming at least a part of the corrosion prevention treatment layer by any of the hot water transformation treatment, the anodizing treatment, and the chemical conversion treatment among the corrosion prevention treatments, it is preferable to perform the degreasing treatment described above in advance. In addition, when using the metal foil in which the degreasing process was carried out as the metal foil layer 13, in the formation of the corrosion prevention treatment layer 14, it is necessary to degrease again.

  The coating agent used for the coating type chemical conversion treatment preferably contains trivalent chromium. The coating agent may also include at least one polymer selected from the group consisting of cationic polymers and anionic polymers described later.

  Further, among the above treatments, especially in the hydrothermal transformation treatment and the anodizing treatment, the surface of the aluminum foil is dissolved with a treating agent to form an aluminum compound (boehmite, alumite) having excellent corrosion resistance. Therefore, the metal foil layer 13 using the aluminum foil to the corrosion prevention treatment layer 14 has a form in which a co-continuous structure is formed, so it is included in the definition of chemical conversion treatment, but is included in the definition of chemical conversion treatment as described later. It is also possible to form the corrosion protection treatment layer 14 only by a pure coating method. As this method, for example, a sol of a rare earth element-based oxide such as cerium oxide having an average particle diameter of 100 nm or less as a material having a corrosion prevention effect (inhibitor effect) of aluminum and suitable also from an environmental aspect. The method of using By using this method, even with a general coating method, it is possible to provide a metal foil such as an aluminum foil with a corrosion prevention effect.

  Examples of the sol of the rare earth element-based oxide include sols using various solvents such as aqueous, alcohol, hydrocarbon, ketone, ester and ether. Among them, aqueous sols are preferred.

  In order to stabilize the dispersion of the rare earth element oxide sol, usually, an inorganic acid such as nitric acid, hydrochloric acid or phosphoric acid or a salt thereof, or an organic acid such as acetic acid, malic acid, ascorbic acid or lactic acid is dispersed It is used as a stabilizer. Among these dispersion stabilizers, in particular phosphoric acid, in the packaging material 10, (1) dispersion stabilization of the sol, (2) improvement of adhesion to the metal foil layer 13 utilizing the aluminum chelating ability of phosphoric acid , (3) Addition of electrolyte resistance by capturing (passivation) aluminum ions eluted under the influence of hydrofluoric acid, and (4) corrosion prevention treated layer 14 by which dehydration condensation of phosphoric acid is likely to occur even at low temperatures The cohesion of the oxide layer is expected to be improved.

  Examples of the above phosphoric acid or salts thereof include orthophosphoric acid, pyrophosphoric acid, metaphosphoric acid, or alkali metal salts and ammonium salts thereof. Among them, in order to express the function in the packaging material 10, condensed phosphoric acid such as trimetaphosphoric acid, tetrametaphosphoric acid, hexametaphosphoric acid, ultrametaphosphoric acid or the like, or an alkali metal salt or ammonium salt thereof is preferable. Also, in view of the dry film forming property (drying ability, heat quantity) when forming the corrosion prevention treated layer 14 made of rare earth oxide by various coating methods using the above-mentioned sol of rare earth oxide, dehydration condensation at low temperature The sodium salt is more preferable from the viewpoint of excellent in properties. As a phosphate, a water-soluble salt is preferable.

  The compounding ratio of phosphoric acid (or a salt thereof) to the rare earth element oxide is preferably 1 to 100 parts by mass with respect to 100 parts by mass of the rare earth element oxide. When the compounding ratio is 1 part by mass or more with respect to 100 parts by mass of the rare earth element oxide, the rare earth element oxide sol becomes more stable, and the function of the packaging material 10 becomes better. The mixing ratio is more preferably 5 parts by mass or more with respect to 100 parts by mass of the rare earth element oxide. Moreover, if the said compounding ratio is 100 mass parts or less with respect to 100 mass parts of rare earth element oxides, the function of rare earth element oxide sol will increase, and it is excellent in the performance which prevents corrosion of electrolyte solution. As for the said compounding ratio, 50 mass parts or less are more preferable with respect to 100 mass parts of rare earth element oxides, and 20 mass parts or less are more preferable.

  Since the corrosion prevention treatment layer 14 formed of the rare earth oxide sol is an aggregate of inorganic particles, there is a possibility that the cohesion of the layer itself may be reduced even after the process of drying and curing. Therefore, in order to supplement the cohesion, it is preferable that the corrosion prevention treatment layer 14 in this case be complexed with the following anionic polymer or cationic polymer.

  As an anionic polymer, the polymer which has a carboxy group is mentioned, For example, the copolymer which copolymerized poly (meth) acrylic acid (or its salt) or poly (meth) acrylic acid as a main component is mentioned. As a copolymerization component of this copolymer, alkyl (meth) acrylate monomers (as an alkyl group, a methyl group, an ethyl group, an n-propyl group, an i-propyl group, an n-butyl group, an i-butyl group, t-Butyl group, 2-ethylhexyl group, cyclohexyl group etc.); (Meth) acrylamide, N-alkyl (meth) acrylamide, N, N-dialkyl (meth) acrylamide (as alkyl group, 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-dialkoxy (Meth) acrylamide, (as an alkoxy group, a methoxy group, an ethoxy group, a butoxy group, an isobutoxy group, etc.), -An amide group-containing monomer such as methylol (meth) acrylamide and N-phenyl (meth) acrylamide; a hydroxyl group-containing monomer such as 2-hydroxyethyl (meth) acrylate and 2-hydroxypropyl (meth) acrylate; glycidyl (meth) acrylate, Glycidyl group-containing monomers such as allyl glycidyl ether; Silane-containing monomers such as (meth) acryloxypropyltrimethoxysilane, (meth) acryloxypropyltriethoxysilane; isocyanate group-containing monomers such as (meth) acryloxypropyl isocyanate It can be mentioned.

  These anionic polymers play a role of improving the stability of the corrosion prevention treatment layer 14 (oxide layer) obtained by using the rare earth element oxide sol. This is achieved by the effect of protecting the hard and brittle oxide layer with an acrylic resin component, and by the effect of capturing ion contamination (especially sodium ion) derived from phosphate contained in the rare earth oxide sol (cation catcher). Be done. That is, when an alkali metal ion such as sodium or an alkaline earth metal ion is particularly included in the corrosion prevention treatment layer 14 obtained by using the rare earth element oxide sol, the corrosion prevention starting from the location containing this ion The treatment layer 14 tends to deteriorate. Therefore, the resistance of the corrosion prevention treatment layer 14 is improved by immobilizing sodium ions and the like contained in the rare earth oxide sol with an anionic polymer.

  The corrosion prevention treatment layer 14 in which an anionic polymer and a rare earth element oxide sol are combined has the same corrosion prevention performance as the corrosion prevention treatment layer 14 formed by subjecting an aluminum foil to a chromate treatment. The anionic polymer is preferably a cross-linked structure of a polyanionic polymer that is essentially water soluble. As a crosslinking agent used for formation of this structure, the compound which has an isocyanate group, glycidyl group, a carboxy group, and an oxazoline group is mentioned, for example.

  As the compound having an isocyanate group, for example, tolylene diisocyanate, xylylene diisocyanate or a hydrogenated product thereof, hexamethylene diisocyanate, 4,4 ′ diphenylmethane diisocyanate or a hydrogenated product thereof, diisocyanates such as isophorone diisocyanate, or these isocyanates Such as adducts reacted with polyhydric alcohols such as trimethylolpropane, buret bodies obtained by reacting with water, or polyisocyanates such as trimer isocyanurate; or polys thereof Examples include blocked polyisocyanates obtained by blocking isocyanates with alcohols, lactams, oximes and the like.

  As a compound having a glycidyl group, for example, ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, propylene glycol, dipropylene glycol, tripropylene glycol, polypropylene glycol, 1,4-butanediol, 1,6-hexanediol, Epoxy compounds obtained by reacting epichlorohydrin with glycols such as neopentyl glycol; Epoxy compounds obtained by reacting epichlorohydrin with polyhydric alcohols such as glycerin, polyglycerin, trimethylolpropane, pentaerythritol, and sorbitol; phthalic acid, terephthalic acid The epoxy compound etc. which made dicarboxylic acid, such as an acid, an oxalic acid, an adipic acid, and epichlorohydrin be made to act are mentioned.

  As a compound which has a carboxy group, various aliphatic or aromatic dicarboxylic acid etc. are mentioned, for example. In addition, alkali (earth) metal salts of poly (meth) acrylic acid and poly (meth) acrylic acid may be used.

  As a compound having an oxazoline group, for example, a low molecular weight compound having two or more oxazoline units, or a polymerizable monomer such as isopropenyl oxazoline, (meth) acrylic acid, (meth) acrylic acid alkyl ester What copolymerized acrylic monomers, such as hydroxyalkyl (meth) acrylate, is mentioned.

  Further, in the anionic polymer, as in the case of a silane coupling agent, an amine and a functional group may be selectively reacted to make a crosslinking point a siloxane bond. In this case, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropyltriethoxysilane, β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, γ-chloropropylmethoxysilane, vinyltrichlorosilane, γ -Mercaptopropyltrimethoxysilane, gamma-aminopropyltriethoxysilane, N-beta (aminoethyl) -gamma-aminopropyltrimethoxysilane, gamma-isocyanatopropyltriethoxysilane, etc. can be used. Among them, epoxysilanes, aminosilanes and isocyanatesilanes are preferable, particularly in consideration of the reactivity with the anionic polymer or the copolymer thereof.

  The ratio of these crosslinking agents to anionic polymer is preferably 1 to 50 parts by mass, and more preferably 10 to 20 parts by mass with respect to 100 parts by mass of the anionic polymer. When the proportion 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 sufficiently. When the proportion 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 above-mentioned crosslinking agent, and may be a method of forming an ionic crosslink using titanium or a zirconium compound.

  Examples of the cationic polymer include polymers having an amine, and polyethyleneimine, an ionic polymer complex composed of a polymer having polyethyleneimine and a carboxylic acid, and a primary amine graft acrylic resin having a primary amine grafted on an acrylic main skeleton, There may be mentioned cationic polymers such as polyallylamine or derivatives thereof and aminophenol.

  The cationic polymer is preferably used in combination with a crosslinking agent having a functional group capable of reacting with an amine / imine such as a carboxy group or a glycidyl group. As the crosslinking agent used in combination with the cationic polymer, a polymer having a carboxylic acid which forms an ionic polymer complex with polyethyleneimine can also be used, for example, a polycarboxylic acid (salt) such as polyacrylic acid or its ionic salt, or this And copolymers having a comonomer introduced therein, polysaccharides having a carboxy group such as carboxymethyl cellulose or its ion salt, and the like. Examples of the polyallylamine include homopolymers or copolymers of allylamine, allylamine amide sulfate, diallylamine, dimethylallylamine and the like. These amines may be free amines or stabilized with acetic acid or hydrochloric acid. Also, as a copolymer component, maleic acid, sulfur dioxide and the like may be used. Furthermore, a type which has been thermally crosslinked by partial methoxylation of a primary amine can also be used, and aminophenol can also be used. In particular, allylamine or its derivative is preferred.

  In the present embodiment, the cationic polymer is also described as one component constituting the corrosion prevention treatment layer 14. The reason is that as a result of intensive investigations using various compounds to impart electrolytic solution resistance and hydrofluoric acid resistance required for the storage material for an electric storage device, the cationic polymer itself also has electrolytic solution resistance and hydrofluoric acid resistance. It is because it turned out that it is a compound which can be given. It is presumed that this factor is because the aluminum foil is prevented from being damaged by supplementing the fluorine ion with a cationic group (anion catcher).

  Cationic polymers are more preferred materials in terms of improved adhesion. In addition, since the cationic polymer is also water-soluble as in the case of the above-mentioned anionic polymer, it is more preferable to form a crosslinked structure to impart water resistance. As the crosslinking agent in forming the crosslinking structure in the cationic polymer, the crosslinking agent described in the section of the anionic polymer can be used. When a rare earth oxide sol is used as the corrosion prevention treatment layer 14, a cationic polymer may be used instead of using the above-mentioned anionic polymer as the protective layer.

  The corrosion prevention treatment layer by chemical conversion treatment represented by chromate treatment is an aluminum foil using a chemical conversion treatment agent in which hydrofluoric acid, hydrochloric acid, nitric acid, sulfuric acid or a salt thereof is compounded to form a gradient structure with the aluminum foil. And a chromium or non-chromium compound to act to form a chemical conversion treatment layer on the aluminum foil. However, since the above chemical conversion treatment uses an acid as a chemical conversion treatment agent, it is accompanied by deterioration of the working environment and corrosion of the coating apparatus. On the other hand, unlike the chemical conversion treatment represented by chromate treatment, the above-described coating type corrosion prevention treatment layer 14 does not need to form a gradient structure with respect to the metal foil layer 13 using an aluminum foil. Therefore, the properties of the coating agent are not restricted by acidity, alkalinity, neutrality, etc., and a good working environment can be realized. In addition, the chromate treatment using a chromium compound is preferably a coating type corrosion prevention treatment layer 14 also from the point of view of alternatives for the environmental health.

  From the above contents, (1) only the rare earth oxide sol, (2) only the anionic polymer, (3) only the cationic polymer, (4) the rare earth oxide as an example of the combination of the coating type corrosion prevention treatment described above Sol + anionic polymer (laminated composite), (5) rare earth oxide sol + cationic polymer (laminated composite), (6) (rare earth oxide sol + anionic polymer: laminated composite) / cationic polymer (laminated composite) Multilayering), (7) (rare earth oxide sol + cationic polymer: lamination composite) / anionic polymer (multilayering), etc. may be mentioned. Among them, (1) and (4) to (7) are preferable, and (4) to (7) are particularly preferable. However, the present embodiment is not limited to the above combination. For example, as an example of the selection of the corrosion prevention treatment, the cationic polymer has good adhesion to the modified polyolefin resin mentioned in the description of the sealant adhesive layer (adhesive resin layer or second adhesive layer) described later. However, since the material is a very preferable material, in the case where the sealant adhesive layer is composed of a modified polyolefin resin, a cationic polymer is provided on the surface in contact with the sealant adhesive layer (for example, configurations (5) and (6)) Design) is possible.

  Moreover, the corrosion prevention treatment layer 14 is not limited to the layer mentioned above. For example, it may be formed using a treating agent in which a phosphoric acid and a chromium compound are mixed with a resin binder (aminophenol or the like), as in a coating type chromate which is a known technique. By using this treating agent, it is possible to obtain a layer having both of the corrosion preventing function and the adhesion. In addition, although it is necessary to consider the stability of the coating solution, both the corrosion prevention function and the adhesion are achieved using a coating agent obtained by previously liquefying the rare earth oxide sol and the polycationic polymer or polyanionic polymer. It can be a combined layer.

Mass per unit area of the corrosion prevention treatment layer 14 is a multilayer structure, be either single-layer structure, preferably ^{0.005~0.200g / m 2, 0.010~0.100g / m} 2 Gayori preferable. If the mass per unit area is 0.005 g / m ² or more, the metal foil layer 13 can be easily provided with a corrosion prevention function. Further, even if the mass per unit area exceeds 0.200 g / m ² , the corrosion prevention function does not change much. On the other hand, when the rare earth oxide sol is used, if the coating film is thick, curing by heat upon drying may be insufficient, which may be accompanied by a decrease in cohesive force. The thickness of the corrosion prevention treatment layer 14 can be converted from its specific gravity.

<Adhesive resin layer 15>
The adhesive resin layer 15 is roughly configured to include an adhesive resin composition as a main component and, if necessary, an additive component. The adhesive resin composition is not particularly limited, but preferably contains a modified polyolefin resin (a) component and a macrophase separated thermoplastic elastomer (b) component. Moreover, it is preferable that an additive component contains the polypropylene of an atactic structure, or the propylene-alpha olefin copolymer (c) of an atactic structure. Each component will be described below.

(Modified polyolefin resin (a))
Modified polyolefin resin (a) is a resin in which an unsaturated carboxylic acid derivative component derived from any of unsaturated carboxylic acid, acid anhydride of unsaturated carboxylic acid and ester of unsaturated carboxylic acid is graft modified to polyolefin resin Is preferred.

  Examples of the polyolefin resin include polyolefin resins such as low density polyethylene, medium density polyethylene, high density polyethylene, ethylene-α-olefin copolymer, homo, block or random polypropylene and propylene-α-olefin copolymer. .

  As a compound used when graft-modifying these polyolefin resin, the unsaturated carboxylic acid derivative component derived from either unsaturated carboxylic acid, an acid anhydride of unsaturated carboxylic acid, or ester of unsaturated carboxylic acid is mentioned. .

  Specifically, as unsaturated carboxylic acids, for example, acrylic acid, methacrylic acid, maleic acid, fumaric acid, itaconic acid, citraconic acid, tetrahydrophthalic acid, bicyclo [2,2,1] hept-2-ene-5, 6-dicarboxylic acid etc. are mentioned.

  As an acid anhydride of unsaturated carboxylic acid, for example, maleic anhydride, itaconic anhydride, citraconic anhydride, tetrahydrophthalic anhydride, bicyclo [2,2,1] hept-2-ene-5,6-dicarboxylic anhydride Acid anhydrides of unsaturated carboxylic acids such as

  Examples of esters of unsaturated carboxylic acids include methyl acrylate, methyl methacrylate, ethyl methacrylate, butyl methacrylate, dimethyl maleate, monomethyl maleate, diethyl fumarate, dimethyl itaconate, diethyl citraconate, tetrahydrophthalic anhydride Dimethyl, esters of unsaturated carboxylic acids such as bicyclo [2,2,1] hept-2-ene-5,6-dicarboxylic acid dimethyl, and the like can be mentioned.

  The modified polyolefin resin (a) is to graft polymerize (graft-modify) 0.2 to 100 parts by mass of the above-mentioned unsaturated carboxylic acid derivative component with respect to 100 parts by mass of the base polyolefin resin in the presence of a radical initiator. Can be manufactured by 50-250 degreeC is preferable and, as for the reaction temperature of graft | grafting modification, 60-200 degreeC is more preferable. The reaction time is appropriately set according to the production method, but in the case of melt graft polymerization by a twin screw extruder, for example, within the residence time of the extruder, specifically 2 to 30 minutes is preferable, 5 to 10 Minutes are more preferred. The graft modification can be carried out under either normal pressure or increased pressure.

  Examples of the radical initiator used for graft modification include organic peroxides such as alkyl peroxide, aryl peroxide, acyl peroxide, ketone peroxide, peroxy ketal, peroxy carbonate, peroxy ester, hydroperoxide and the like Be

  These organic peroxides can be suitably selected and used according to the conditions of the reaction temperature and reaction time mentioned above. For example, in the case of melt graft polymerization by a twin screw extruder, alkyl peroxides, peroxy ketals and peroxy esters are preferable, and specifically, di-t-butyl peroxide, 2,5-dimethyl-2,5-di Preferred is t-butylperoxy-hexyne-3, dicumyl peroxide and the like.

  As the modified polyolefin resin (a), a polyolefin resin modified with maleic anhydride is preferable. For example, "Admar" manufactured by Mitsui Chemicals, "Modic" manufactured by Mitsubishi Chemicals, etc. are suitable. Such modified polyolefin resin (a) component is excellent in the reactivity with various metals and polymers having various functional groups, and thus the adhesiveness can be imparted to the adhesive resin layer 15 by using the reactivity. And electrolytic solution resistance can be improved.

(Macro phase separation thermoplastic elastomer (b))
The macrophase-separated thermoplastic elastomer (b) forms a macrophase-separated structure in the range of a dispersed phase size of more than 200 nm and 50 μm or less relative to the modified polyolefin resin (a).

  When the adhesive resin composition contains the macrophase-separated thermoplastic elastomer (b) component, it is generated when laminating the modified polyolefin resin (a) component as the main component of the adhesive resin layer 15, etc. Residual stress can be released, and thermoelastic adhesion can be imparted to the adhesive resin layer 15. Therefore, the adhesion of the adhesive resin layer 15 is further improved, and the exterior material 10 having more excellent electrolytic solution resistance can be obtained.

  The macrophase-separated thermoplastic elastomer (b) is present like islands on the modified polyolefin resin (a), but when the dispersed phase size is 200 nm or less, it is difficult to impart viscoelastic improvement in adhesion. become. On the other hand, if the dispersed phase size exceeds 50 μm, the modified polyolefin resin (a) and the macrophase-separating thermoplastic elastomer (b) are essentially incompatible with each other, so that the lamination suitability (processability) is significantly reduced. The physical strength of the adhesive resin layer 15 tends to decrease. From the above, the dispersed phase size is preferably 500 nm to 10 μm.

  Such macrophase-separating thermoplastic elastomer (b) is selected, for example, from 1-butene, 1-pentene, 1-hexene, 1-octene, 4-methyl-1-pentene to ethylene and / or propylene. The polyolefin-type thermoplastic elastomer which copolymerized the alpha-olefin is mentioned.

  Moreover, as a macro phase-separating thermoplastic elastomer (b) component, a commercial item can be used. For example, "Tafmer" manufactured by Mitsui Chemicals, "Zelas" manufactured by Mitsubishi Chemicals, "Cataloy" manufactured by Montel Etc. are suitable.

  In the adhesive resin layer 15, the content of the macrophase-separated thermoplastic elastomer (b) component to the modified polyolefin resin (a) component in the adhesive resin composition is 100 parts by mass of the modified polyolefin resin (a) component The amount is preferably 1 to 40 parts by mass, and more preferably 5 to 30 parts by mass. Here, if the content of the macrophase-separated thermoplastic elastomer (b) component is less than 1 part by mass, improvement in the adhesion of the adhesive resin layer can not be expected. On the other hand, when the content of the macrophase-separated thermoplastic elastomer (b) component exceeds 40 parts by mass, the compatibility between the modified polyolefin resin (a) component and the macrophase-separated thermoplastic elastomer (b) component is inherently low. Processability is likely to be significantly reduced. Moreover, since the macrophase-separating thermoplastic elastomer (b) component is not a resin exhibiting adhesion, the adhesion of the adhesive resin layer 15 to other layers such as the sealant layer 16 and the corrosion prevention treatment layer 14 is likely to be reduced. .

(Atactic polypropylene or atactic propylene-α-olefin copolymer (c))
The adhesive resin layer 15 preferably contains, as an additive component, polypropylene having an atactic structure or a propylene-α-olefin copolymer having an atactic structure (hereinafter, simply referred to as “component (c)”). Here, the component (c) is a completely amorphous resin component.

  Hereinafter, the effect of adding the additive component (c) to the adhesive resin composition as the main component in the adhesive resin layer 15 will be described.

  The component (c) is compatible with the modified polyolefin resin (a) component in the adhesive resin composition when the adhesive resin layer 15 is in a molten state, but is discharged out of the crystal during crystallization accompanying cooling. , Phase separation. Thereby, a component (c) does not inhibit the crystallinity degree of the modified polyolefin resin (a) component in the adhesive resin composition which is a main component. Further, by adding the component (c) into the adhesive resin layer 15, the concentration of the modified polyolefin resin (a) component is diluted by the component (c) to suppress the crystal growth, so the adhesive component of the base resin It is possible to reduce the crystal size (spherulite size) of (that is, the modified polyolefin resin (a) component). Moreover, the component (c) discharged | emitted out of a crystal | crystallization disperse | distributes uniformly around the microsphere crystal of a modified polyolefin resin (a) component.

By the way, it is conventionally known that the "whitening phenomenon" occurs when the exterior material is cold-formed. Here, the mechanism of the whitening phenomenon will be described by taking the adhesive resin layer 15 in which the macrophase separated thermoplastic elastomer (b) is blended with the modified polyolefin resin (a) as an example.
(1) The modified polyolefin resin (a) in the adhesive resin layer 15 is crystallized by heat treatment at the time of thermal lamination.
(2) Since the modified polyolefin resin (a) and the macrophase-separated thermoplastic elastomer (b) are incompatible, strain occurs at the interface of the two due to the crystallization behavior of (1).
(3) When stress is applied at the time of molding, a crack is generated at the interface between the two, and void-clays are formed.
(4) Light is scattered by void-clays, and a whitening phenomenon occurs due to diffuse reflection of optical light.

  That is, in order to suppress the whitening phenomenon, "the crystallization of the modified polyolefin resin (a) does not proceed by the amount of heat at the time of thermal lamination (that is, the crystallization is made difficult)", and "the modified polyolefin resin (a)" It is known that “improvement of adhesion to the macrophase-separated thermoplastic elastomer (b)” is important.

  On the other hand, the crystal size (spherulite size) of the modified polyolefin resin (a) component is obtained by adding the component (c) as an additive component to the adhesive resin composition as the main component of the adhesive resin layer 15 Can be made small, so that flexible and strong film characteristics can be obtained. In addition, by uniformly dispersing the component (c) around the modified polyolefin resin (a), stress relaxation becomes possible uniformly, and the occurrence of void craze can be suppressed. It is considered possible to alleviate the "whitening phenomenon".

  As described above, by adding the component (c) as an additive component to the adhesive resin composition which is the main component of the adhesive resin layer 15, the transparency of the adhesive resin layer 15 is increased, and at the time of molding. It is possible to alleviate the whitening phenomenon associated with stress. Thereby, molding whitening is also improved, and it becomes possible to improve the insulation (bending resistance) associated with the bending stress of the packaging material 10. Moreover, since flexibility can be given while maintaining the crystallinity degree of the modified polyolefin resin component (a) in the adhesive resin layer 15, it is possible to suppress the reduction in the lamination strength at the electrolyte solution swelling of the exterior material 10 It becomes.

  The lower limit of the proportion of the component (c) in the adhesive resin layer 15 is preferably 2.5% by mass, and more preferably 5% by mass or more. On the other hand, the upper limit value is preferably 60% by mass. Here, if the proportion of the component (c) in the adhesive resin layer 15 is less than 2.5% by mass, the effect of adding the component (c) as described above tends not to be sufficiently obtained. is there. On the other hand, if it exceeds 60% by mass (that is, the ratio of the adhesive resin composition is less than 40% by mass), adhesion of the adhesive resin layer 15 to other layers such as the sealant layer 16 and the corrosion prevention treatment layer 14 There is a tendency for the sex to decrease.

(Propylene-α-olefin copolymer of isotactic structure (d))
The adhesive resin layer 15 further contains, as an additive component, a propylene-α-olefin copolymer having an isotactic structure (hereinafter simply referred to as “component (d)”) in addition to the component (c) described above. Is preferred.

  Here, in the adhesive resin component which is the main component of the adhesive resin layer 15, the component (d) acts as a compatible rubber component, particularly when the modified polyolefin resin (a) is a polypropylene-based adhesive resin, The crystallization of the modified polyolefin resin (a) is suppressed.

  That is, by adding the component (d) as an additive component to the adhesive resin component which is the main component of the adhesive resin layer 15, flexibility for relieving stress can be imparted, so that the electrolytic solution laminating strength It is possible to improve the heat seal strength (in particular, the electrolyte resistance) and to improve the degassing seal strength while suppressing the decrease in In addition, by combining the component (c) and the component (d) as an additive component, it is possible to further improve the whitening phenomenon and the bending insulation resistance.

  The ratio of the additive component (that is, the total amount of the component (c) and the component (d)) in the adhesive resin layer 15 is preferably 5 to 60% by mass. Here, when the ratio of the additive component in the adhesive resin layer 15 is less than 5% by mass (that is, the ratio of the adhesive resin composition exceeds 95% by mass), the additive as described above is added. There is a tendency that the effect by the addition can not be obtained sufficiently. On the other hand, if it exceeds 60% by mass (that is, the ratio of the adhesive resin composition is less than 40% by mass), adhesion of the adhesive resin layer 15 to other layers such as the sealant layer 16 and the corrosion prevention treatment layer 14 There is a tendency for the sex to decrease.

  In addition, as an analysis method of the component (c) which is an additive component in the adhesive resin layer 15, for example, it is possible to quantify by stereoregularity evaluation by nuclear magnetic resonance spectroscopy (NMR).

  On the other hand, as the analysis of the component (d), an absorber attributable to an α-olefin branch and a characteristic absorber of the modified polyolefin resin (a) using Fourier transform infrared spectroscopy (FT-IR) The compounding ratio can be confirmed by preparing a calibration curve with the absorber belonging to.

  The adhesive resin layer 15 is composed of an adhesive resin composition (i.e., the modified polyolefin resin (a) component and the macrophase-separating thermoplastic elastomer (b) component) and an additive component (i.e. the component (c) and the component (d) In addition to the above, if necessary, various additives such as flame retardants, slip agents, antiblocking agents, antioxidants, light stabilizers, tackifiers and the like may be contained.

  The thickness of the adhesive resin layer 15 is not particularly limited, but is preferably equal to or less than that of the sealant layer 16 from the viewpoint of stress relaxation and moisture / electrolyte permeation.

<Sealant layer 16>
The sealant layer 16 is a layer that provides the exterior material 10 with a sealing property by heat sealing. The sealant layer 16 comprises 60 to 95% by mass of (A) a propylene-ethylene random copolymer, and 5 to 40% by mass of a polyolefin-based elastomer having a melting point of 150 ° C. or less containing (B) butene-1 as a comonomer. It is a layer formed of the resin composition to be contained. Each component will be described below.

((A) Propylene-Ethylene Random Copolymer)
(A) Propylene-ethylene random copolymer is excellent in heat sealability at low temperature compared with propylene-ethylene block copolymer and propylene homopolymer, and improves the sealing property involving the electrolytic solution As a result, it is possible to suppress the occurrence of an over-sealed portion due to the influence of the (B) polyolefin-based elastomer.

  In the (A) propylene-ethylene random copolymer, the ethylene content is preferably 0.1 to 10% by mass, more preferably 1 to 7% by mass, and 2 to 5% by mass. More preferable. When the ethylene content is 0.1% by mass or more, the melting point lowering effect by copolymerizing ethylene is sufficiently obtained, and there is a tendency that the sealing characteristics involving the electrolytic solution can be further improved. When the ethylene content is 10% by mass or less, it is possible to suppress the melting point from being excessively lowered, and it is possible to more sufficiently suppress the occurrence of the excessive sealing portion. The ethylene content can be calculated from the mixing ratio of monomers at the time of polymerization.

  The melting point of the (A) propylene-ethylene random copolymer is preferably 120 to 145 ° C, and more preferably 125 to 140 ° C. When the melting point is 120 ° C. or more, the occurrence of the over-sealed portion tends to be sufficiently suppressed. When the melting point is 145 ° C. or less, the sealing characteristics involving the electrolyte tend to be further improved.

  The weight-average molecular weight of the (A) propylene-ethylene random copolymer is preferably adjusted so that the melting point falls within the above range, preferably 10,000 to 10,000,000, and more preferably It is 100,000 to 1,000,000.

  The (A) propylene-ethylene random copolymer may be acid-modified, and may be, for example, an acid-modified propylene-ethylene random copolymer in which maleic anhydride is graft-modified. By using the acid-modified propylene-ethylene random copolymer, the adhesion to the tab lead can be maintained even without the tab sealant.

  The (A) propylene-ethylene random copolymer can be used singly or in combination of two or more.

  In the resin composition for forming the sealant layer, the content of the component (A) is 60 to 95% by mass, preferably 60 to 90% by mass, based on the total solid content of the resin composition, More preferably, it is 85% by mass. When the content of the component (A) is 60% by mass or more, the sealing characteristics involving the electrolytic solution can be improved by the effect of using the component (A) itself. Further, by setting the content of the component (A) to 60% by mass or more, the component (B) can be prevented from being present in excess, so that the decrease in heat resistance of the sealant layer 16 can be suppressed, and the excessive sealing portion Can be suppressed. On the other hand, by setting the content of the component (A) to 95% by mass or less, the component (B) can be contained in an amount of 5% by mass or more. You can get enough.

((B) Polyolefin elastomer having a melting point of 150 ° C. or less containing butene-1 as a comonomer)
(B) A polyolefin-based elastomer having a melting point of 150 ° C. or less containing butene-1 as a co-monomer contributes to the improvement of seal characteristics involving an electrolytic solution including degashing heat seal strength, and contributes to the suppression of the occurrence of mold whitening. Do.

  The polyolefin elastomer (B) may or may not be compatible with the component (A), but the compatible (B-1) compatible system has compatibility. It is preferable to include both a polyolefin-based elastomer and a non-compatible (B-2) incompatible polyolefin-based elastomer. Here, compatibility with the component (A) (compatible system) means that the dispersed phase size is 1 nm or more and less than 500 nm in the propylene-ethylene random copolymer resin constituting the component (A). means. Not compatible (incompatible system) means dispersed in a propylene-ethylene random copolymer resin constituting the component (A) with a dispersed phase size of 500 nm or more and less than 20 μm.

  Examples of the (B-1) compatible polyolefin elastomer include a propylene-butene-1 random copolymer.

  Examples of the (B-2) incompatible polyolefin-based elastomer include ethylene-butene-1 random copolymer.

  The melting point of the polyolefin elastomer (B) is required to be 150 ° C. or less, but it is 60 to 120 ° C. from the viewpoint of suppression of excessive sealing portion, suppression of mold whitening and improvement of sealing characteristics involving the electrolyte. It is preferable that it is and it is more preferable that it is 65-90 degreeC. By setting the melting point to 150 ° C. or less, the sealing characteristics related to the electrolytic solution, in particular the degashing heat seal strength can be improved. Further, if the melting point is 60 ° C. or more, it is advantageous in terms of suppressing the occurrence of the excessive sealing portion.

  The polyolefin elastomer (B) can be used alone or in combination of two or more.

  In the resin composition for forming a sealant layer, the content of the component (B) is 5 to 40% by mass, preferably 10 to 40% by mass, based on the total solid content of the resin composition, and 15 to 15%. More preferably, it is 40% by mass. When the content of the component (B) is 5% by mass or more, the effect of improving the sealing characteristics related to the electrolytic solution, particularly the degassing heat seal strength, can be sufficiently obtained. On the other hand, by setting the content of the component (B) to 40% by mass or less, the decrease in heat resistance of the sealant layer 16 can be suppressed, and the generation of the excessive sealing portion can be suppressed.

  When the component (B) contains the (B-1) compatible polyolefin-based elastomer and the (B-2) incompatible polyolefin-based elastomer, the content ratio of the both ((B-1) compatible polyolefin-based elastomer / ( It is preferable that it is 0.5-3 in mass ratio, and, as for B-2) incompatible polyolefin-type elastomer, it is more preferable that it is 1-2. By setting the content ratio in the above-mentioned range, it is possible to improve in a well-balanced manner the molding whitening resistance and the sealing characteristics to which the electrolytic solution relates.

(Additional component)
The resin composition for forming a sealant layer may further contain other components other than the component (A) and the component (B) described above. As other components other than the component (A) and the component (B), for example, another resin such as LDEP (low density polyethylene) may be added to improve the drawability and processability. It is preferable that content of the other resin component to add is 10 mass% or less on the basis of solid content whole quantity of a resin composition. Moreover, as a component other than resin, a slip agent, an antiblocking agent, an antioxidant, a light stabilizer, a flame retardant etc. are mentioned, for example. It is preferable that content of components other than these resin is 5 mass% or less on the basis of solid content whole quantity of a resin composition.

  The thickness of the sealant layer 16 is not particularly limited, but specifically, for example, the range of 5 to 100 μm is preferable, and the range of 10 to 60 μm is more preferable.

  In the sealant layer 16, the presence of butene-1 can be confirmed by attribution by FT-IR (Fourier transform infrared spectrophotometer). In addition, the content of butene-1 is the transmittance or absorbance of characteristic absorption bands of the components (A) and (B) using a resin composition containing a known amount of an elastomer containing a known amount of butene-1. It is possible to confirm by preparing a calibration curve. In addition, the butene-1 content of each of the (B-1) compatible polyolefin elastomer and the (B-2) incompatible polyolefin elastomer is similarly imaged in the characteristic absorption band of FT-IR. It can be confirmed by conducting and mapping with the absorption band derived from butene-1 by microscopic FT-IR (transmission method). In addition, it is also possible to confirm the presence and content of butene-1 by dissolving the sealant layer 16 with a solvent and measuring by NMR other than FT-IR.

  As mentioned above, although the preferable embodiment of the exterior material for electrical storage devices of this invention was explained in full detail, this invention is not limited to this specific embodiment, It is described in the scope of the present invention described in the claim. Various changes and modifications are possible within the scope of the present invention.

  For example, although FIG. 1 shows the case where the corrosion prevention treatment layer 14 is formed on the surface on the adhesive resin layer 15 side of the metal foil layer 13, the corrosion prevention treatment layer 14 is a first layer of the metal foil layer 13. It may be formed on the surface on the adhesive layer 12 side, or may be formed on both sides of the metal foil layer 13. When the corrosion prevention treatment layer 14 is formed on both sides of the metal foil layer 13, the structure of the corrosion prevention treatment layer 14 formed on the first adhesive layer 12 side of the metal foil layer 13 and the metal foil layer 13 The structure of the corrosion prevention treatment layer 14 formed on the adhesive resin layer 15 side may be the same or different.

  Further, FIG. 1 shows the case where the metal foil layer 13 and the sealant layer 16 are laminated by using the adhesive resin layer 15, but as in the case of the power storage device packaging material 20 shown in FIG. The metal foil layer 13 and the sealant layer 16 may be laminated using the adhesive layer 17 of Hereinafter, the second adhesive layer 17 will be described.

<Second adhesive layer 17>
The second adhesive layer 17 is a layer for bonding the metal foil layer 13 on which the corrosion prevention treatment layer 14 is formed and the sealant layer 16. For the second adhesive layer 17, a general adhesive for bonding the metal foil layer and the sealant layer can be used.

  When the corrosion prevention treatment layer 14 has a layer containing at least one polymer selected from the group consisting of the above-described cationic polymer and anionic polymer, the second adhesive layer 17 is included in the corrosion prevention treatment layer 14 The layer preferably contains a compound having reactivity with the above-mentioned polymer (hereinafter, also referred to as “reactive compound”).

  For example, when the corrosion prevention treatment layer 14 contains a cationic polymer, the second adhesive layer 17 contains a compound having reactivity with the cationic polymer. When the corrosion prevention treatment layer 14 contains an anionic polymer, the second adhesive layer 17 contains a compound having reactivity with the anionic polymer. Also, when the corrosion prevention treatment layer 14 contains a cationic polymer and an anionic polymer, the second adhesive layer 17 contains a compound having reactivity with the cationic polymer and a compound having reactivity with the anionic polymer. . However, the second adhesive layer 17 does not necessarily have to contain the above two types of compounds, and may contain a compound having reactivity with both the cationic polymer and the anionic polymer. Here, "having reactivity" means forming a covalent bond with a cationic polymer or an anionic polymer. The second adhesive layer 17 may further contain an acid-modified polyolefin resin.

  Examples of the compound having reactivity with the cationic polymer include at least one compound selected from the group consisting of polyfunctional isocyanate compounds, glycidyl compounds, compounds having a carboxy group, and compounds having an oxazoline group.

  As these polyfunctional isocyanate compounds, glycidyl compounds, compounds having a carboxy group, and compounds having an oxazoline group, the polyfunctional isocyanate compounds, glycidyl compounds, carboxy groups exemplified above as a crosslinking agent for forming a cationic polymer into a crosslinked structure And compounds having an oxazoline group. Among these, polyfunctional isocyanate compounds are preferable in that they have high reactivity with the cationic polymer and easily form a crosslinked structure.

  Examples of the compound having reactivity with the anionic polymer include at least one compound selected from the group consisting of glycidyl compounds and compounds having an oxazoline group. As a glycidyl compound and the compound which has an oxazoline group, the glycidyl compound illustrated above as a crosslinking agent for making a cationic polymer into a crosslinked structure, the compound which has an oxazoline group, etc. are mentioned. Among these, glycidyl compounds are preferable in that they have high reactivity with anionic polymers.

  When the second adhesive layer 17 contains an acid-modified polyolefin resin, it is preferable that the reactive compound be also reactive with the acid group in the acid-modified polyolefin resin (that is, form a covalent bond with the acid group). This further enhances the adhesion to the corrosion prevention treatment layer 14. In addition, the acid-modified polyolefin resin has a crosslinked structure, and the solvent resistance of the packaging material 10 is further improved.

  The content of the reactive compound is preferably equivalent to 10 times the amount of the acid group in the acid-modified polyolefin resin. If the amount is equal to or more than the equivalent amount, the reactive compound sufficiently reacts with the acid group in the acid-modified polyolefin resin. On the other hand, if it exceeds 10 times the amount, the cross-linked structure with the acid-modified polyolefin resin becomes insufficient, and there is a concern that the physical properties such as the solvent resistance described above may be reduced.

  The acid-modified polyolefin resin is one in which an acidic group is introduced into a polyolefin resin. As an acidic group, a carboxy group, a sulfonic acid group, etc. are mentioned, A carboxy group is especially preferable. As an acid modified polyolefin resin, the thing similar to what was illustrated as modified polyolefin resin (a) used for the adhesive resin layer 15 can be used.

  The second adhesive layer 17 may contain various additives such as a flame retardant, a slip agent, an antiblocking agent, an antioxidant, a light stabilizer, and a tackifier.

  In addition, a silane coupling agent may be contained in the general adhesive used in order to adhere | attach a metal foil layer and a sealant layer. This is because the incorporation of a silane coupling agent promotes adhesion and enhances the adhesion strength. However, when an adhesive containing a silane coupling agent is used, depending on the type of functional group contained in the silane coupling agent, components other than the silane coupling agent contained in the adhesive layer and the silane coupling agent may A reaction may occur to adversely affect the original intended crosslinking reaction. Therefore, it is preferable that the adhesive used to bond the metal foil layer and the sealant layer does not contain a silane coupling agent.

  When the second adhesive layer 17 contains the above-described reactive compound, a covalent bond is formed with the polymer in the corrosion prevention layer 14, and the adhesion strength between the corrosion prevention layer 14 and the second adhesive layer 17 is obtained. Improve. Therefore, it is not necessary to mix a silane coupling agent in the second adhesive layer 17 for the purpose of promoting adhesion, and it is preferable that the second adhesive layer 17 does not contain a silane coupling agent.

  The thickness of the second adhesive layer 17 is preferably 3 to 50 μm, and more preferably 3 to 10 μm. If the thickness of the second adhesive layer 17 is equal to or more than the lower limit value, excellent adhesion can be easily obtained. If the thickness of the second adhesive layer 17 is equal to or less than the upper limit value, the amount of moisture transmitted from the side end face of the exterior material 10 is reduced.

  The configuration of the power storage device exterior material 20 other than the second adhesive layer 17 is the same as that of the power storage device exterior material 10. The thickness of the sealant layer 16 in the storage device covering material 20 is adjusted in accordance with the thickness of the second adhesive layer 17. The thickness of the sealant layer 16 in the storage battery packaging material 20 is not particularly limited, but is preferably in the range of 5 to 100 μm, and more preferably in the range of 10 to 80 μm.

  Moreover, although the case where the base material layer 11 and the metal foil layer 13 were adhere | attached through the 1st adhesive bond layer 12 was shown in FIG.1 and FIG.2, the 1st adhesive bond layer 12 was not interposed. Alternatively, the base layer 11 may be directly formed on the metal foil layer 13 by a coating method. In the present specification, the base material layer thus directly formed on the metal foil layer 13 by the coating method is referred to as a covering layer. In addition, the corrosion prevention treatment layer 14 may be formed on the surface on the coating layer side of the metal foil layer 13. The coating layer will be described below.

<Covering layer>
The covering layer imparts heat resistance in the sealing step when manufacturing the power storage device, and plays a role of suppressing the generation of pinholes that may occur during processing or circulation.

  The covering layer is formed of a resin, and is directly formed on one surface of the metal foil layer 13 without an adhesive or the like. Such a coating layer can be formed by applying or coating a resin material to be a coating layer on the metal foil layer 13.

  As a resin material which forms a coating layer, polyester, a fluorine resin, acrylic resin etc. can be used, Especially, urethane acrylate is preferable. This is because the coating film made of urethane acrylate has suitable spreadability. As a coating liquid containing these resin materials, a two-component curable coating liquid may be used.

  3 micrometers-30 micrometers are preferable, and, as for the thickness of a coating layer, 5 micrometers-20 micrometers are more preferable. The covering layer is formed directly on the metal foil layer 13, and therefore, by setting the thickness of the covering layer to 20 μm or less, the covering layer can be easily made thinner than the conventional covering material.

[Method of manufacturing exterior material]
Next, an example of a method of manufacturing the packaging material 10 shown in FIG. 1 will be described. In addition, the manufacturing method of the exterior material 10 is not limited to the following method.

  In the method of manufacturing the packaging material 10 of the present embodiment, a process of laminating the corrosion prevention treatment layer 14 on the metal foil layer 13, a process of bonding the base material layer 11 and the metal foil layer 13, an adhesive resin layer 15 and The sealant layer 16 is further laminated to produce a laminate, and, if necessary, the obtained laminate is heat-treated.

(Step of laminating the corrosion prevention treatment layer 14 on the metal foil layer 13)
This step is a step of forming the corrosion prevention treatment layer 14 on the metal foil layer 13. As the method, as described above, the metal foil layer 13 may be subjected to a degreasing treatment, a hydrothermal transformation treatment, an anodizing treatment, a chemical conversion treatment, or a method of applying a coating agent having a corrosion prevention performance, etc. Be

  Further, as shown in FIG. 1, when the corrosion prevention treatment layer 14 is a multilayer, for example, a coating liquid (coating agent) constituting the corrosion prevention treatment layer on the lower layer side (the metal foil layer 13 side) Coating and baking to form the first layer, and then applying the coating liquid (coating agent) constituting the corrosion prevention treated layer on the upper layer side to the first layer and baking it to form the second layer Good. The second layer can also be formed in the step of laminating the adhesive resin layer 15 and the sealant layer 16 described later.

  For degreasing treatment, spray method or immersion method, for hot water transformation treatment and anodizing treatment, for immersion method, and for chemical conversion treatment, appropriately select immersion method, spray method, coating method, etc. according to the type of chemical conversion treatment. You can do it.

  As a coating method of a coating agent having corrosion prevention performance, various methods such as gravure coating, reverse coating, roll coating, and bar coating can be used.

  As described above, various treatments may be performed on either or both sides of the metal foil, but in the case of single-sided treatment, the treated surface is preferably applied to the side on which the adhesive resin layer 15 is laminated. In addition, you may perform the said process also to the surface of the base material layer 11 according to a request | requirement.

Moreover, neither the coating amount of the coating agent for forming the first layer and the second layer is preferably ^{0.005~0.200g / m 2, 0.010~0.100g / m} 2 is more preferable.

  Moreover, when drying curing is required, it can carry out in 60-300 degreeC as base-material temperature according to the drying conditions of the corrosion prevention processing layer 14 to be used.

(Step of bonding the base material layer 11 and the metal foil layer 13)
This step is a step of bonding the metal foil layer 13 provided with the corrosion prevention treatment layer 14 and the base layer 11 via the first adhesive layer 12. As a method of bonding, both are bonded together by the material which comprises the 1st adhesive bond layer 12 mentioned above using methods, such as dry lamination, nonsolvent lamination, wet lamination. The first adhesive layer 12 is in the range of 1 to 10 g / ^{m 2} as a dry coating amount, more preferably provided in a range of 3 to 7 g / ^{m 2.}

(Lamination process of adhesive resin layer 15 and sealant layer 16)
This step is a step of forming the adhesive resin layer 15 and the sealant layer 16 on the corrosion prevention treated layer 14 formed in the previous step. As the method, there is a method of sand laminating the adhesive resin layer 15 together with the sealant layer 16 using an extrusion laminating machine. Furthermore, lamination can also be performed by a tandem lamination method in which the adhesive resin layer 15 and the sealant layer 16 are extruded, or a co-extrusion method.

  In this step, the respective layers are laminated in the order of base material layer 11 / first adhesive layer 12 / metal foil layer 13 / corrosion prevention treatment layer 14 / adhesive resin layer 15 / sealant layer 16 as shown in FIG. The resulting laminate is obtained.

  In addition, the adhesive resin layer 15 may be made to laminate the dry-blended material directly by the extrusion laminating machine so that it will become the material composition mentioned above, or a single screw extruder, a twin screw extruder, or the like in advance. The granulated adhesive resin layer 15 after melt blending using a melt-kneading apparatus such as a Brabender mixer may be laminated using an extrusion laminating machine.

  Further, when forming a multilayer corrosion prevention treatment layer 14, if the extrusion laminating machine is provided with a unit capable of applying the anchor coat layer, the second layer of the corrosion prevention treatment layer 14 is formed by the unit. It may be coated.

(Heat treatment process)
This step is a step of heat-treating the laminate. By heat treating the laminate, the adhesion between the metal foil layer 13 / corrosion prevention treatment layer 14 / adhesive resin layer 15 / sealant layer 16 is improved, and more excellent electrolytic solution resistance and hydrofluoric acid resistance are imparted. In addition, the effect of suppressing the progress of crystallization of the adhesive resin layer 15 and the sealant layer 16 and suppressing the occurrence of the whitening phenomenon at the time of molding can also be obtained. Therefore, in this step, it is preferable to improve the adhesion between the above-described layers and to perform heat treatment to such an extent that crystallization of the adhesive resin layer 15 and the sealant layer 16 is not promoted. The temperature of the heat treatment depends on the kind of the material constituting the adhesive resin layer 15 and the sealant layer 16 and the like, but as a guide, the highest attainable temperature of the laminate is from the melting point of the adhesive resin layer 15 or the sealant layer 16 It is preferable that the heat treatment be performed so as to be 20 to 100 ° C. higher, and it is more preferable that the heat treatment be performed so as to be 20 to 60 ° C. higher than the melting point of the adhesive resin layer 15 or the sealant layer 16. If the maximum temperature reached of the laminate is below this range, crystal nuclei remain and crystallization tends to be promoted. On the other hand, if the maximum temperature reached of the laminate exceeds this range, for example, thermal expansion of the metal foil or thermal contraction of the base material layer after bonding may occur, which may deteriorate the processability and properties. Therefore, although the heat treatment time depends on the treatment temperature, it is desirable to carry out in a short time (for example, less than 30 seconds).

  In addition, it is preferable to cool rapidly in order to suppress crystallization. The cooling rate is preferably about 50 to 100 ° C./second.

  Thus, the exterior material 10 of this embodiment as shown in FIG. 1 can be manufactured.

  Next, an example of a method of manufacturing the packaging material 20 shown in FIG. 2 will be described. In addition, the manufacturing method of the exterior material 20 is not limited to the following method.

  In the method of manufacturing the packaging material 20 of the present embodiment, a process of laminating the corrosion prevention treatment layer 14 on the metal foil layer 13, a process of bonding the base material layer 11 and the metal foil layer 13, and a second adhesive layer A sealant layer 16 is further laminated via 17 to produce a laminate, and, if necessary, the obtained laminate is subjected to an aging treatment. In addition, the process to bond the base material layer 11 and the metal foil layer 13 can be performed similarly to the manufacturing method of the exterior material 10 mentioned above.

(Lamination process of the second adhesive layer 17 and the sealant layer 16)
This step is a step of bonding the sealant layer 16 to the side of the metal foil layer 13 on the side of the corrosion prevention treatment layer 14 via the second adhesive layer 17. A wet process is mentioned as the method of bonding.

  In the case of a wet process, a solution or dispersion of the adhesive constituting the second adhesive layer 17 is applied on the corrosion prevention treated layer 14 and the predetermined temperature (when the adhesive contains an acid-modified polyolefin resin) The solvent is removed at a temperature above its melting point and baking is performed. Thereafter, the sealant layer 16 is laminated to manufacture the exterior material 20. As a coating method, the various coating methods illustrated above are mentioned.

(Aging treatment process)
This step is a step of aging (curing) the laminate. By aging the laminate, adhesion between the metal foil layer 13 / corrosion prevention treatment layer 14 / second adhesive layer 17 / sealant layer 16 can be promoted. Aging treatment can be performed in the range of room temperature to 100 ° C. The aging time is, for example, 1 to 10 days.

  Thus, the exterior material 20 of this embodiment as shown in FIG. 2 can be manufactured.

  The preferred embodiments of the packaging material for a storage battery device and the method of manufacturing the same according to the present invention have been described above in detail, but the present invention is not limited to such specific embodiments, and is described in the claims. Within the scope of the present invention, various modifications and changes are possible. In addition, when manufacturing the exterior material for electrical storage apparatuses provided with a coating layer instead of the base material layer 11 and the 1st adhesive bond layer 12, as above-mentioned, the resin material used as a coating layer is carried out on the metal foil layer 13. A coating layer can be formed by application or coating.

  The packaging material for a storage battery according to the present invention is suitably used as a packaging material for a storage battery, such as a secondary battery such as a lithium ion battery, a nickel hydrogen battery, and a lead storage battery, and an electrochemical capacitor such as an electric double layer capacitor. It can be used. Among them, the packaging material for a power storage device of the present invention is suitable as a packaging material for a lithium ion battery.

  Hereinafter, the present invention will be more specifically described based on examples, but the present invention is not limited to the following examples.

[Material used]
The materials used in Examples and Comparative Examples are shown below.
<Base layer (thickness 25 μm)>
A coextruded multilayer stretched film (manufactured by Gunze) of polyethylene terephthalate film (PET) and nylon film (Ny) was used.

<First adhesive layer (thickness 4 μm)>
A polyurethane-based adhesive (made by Toyo Ink Co., Ltd.) was used in which an adduct-based curing agent of tolylene diisocyanate was blended with a polyester polyol-based main agent.

<First corrosion prevention treatment layer (base layer side)>
(CL-1): "sodium polyphosphate stabilized cerium oxide sol" adjusted to a solid content concentration of 10% by mass was used using distilled water as a solvent. The sodium polyphosphate-stabilized cerium oxide sol was obtained by blending 10 parts by mass of Na salt of phosphoric acid with 100 parts by mass of cerium oxide.
(CL-2): 90% by mass of “polyacrylic acid ammonium salt (manufactured by Toagosei Co., Ltd.)” adjusted to a solid content concentration of 5% by mass using distilled water as a solvent, “acrylic-isopropenyl oxazoline copolymer ( A composition comprising 10% by mass of Nippon Catalyst Co., Ltd.) was used.

<Metal foil layer (thickness 40 μm)>
A soft aluminum foil ("8079 material" manufactured by Toyo Aluminum Co., Ltd.) that has been subjected to annealing degreasing treatment was used.

<Second corrosion prevention treatment layer (sealant layer side)>
(CL-1): "sodium polyphosphate stabilized cerium oxide sol" adjusted to a solid content concentration of 10% by mass was used using distilled water as a solvent. The sodium polyphosphate-stabilized cerium oxide sol was obtained by blending 10 parts by mass of Na salt of phosphoric acid with 100 parts by mass of cerium oxide.
(CL-3): 90% by mass of "polyallylamine (manufactured by Nittobo Co., Ltd.)" adjusted to a solid content concentration of 5% by mass using distilled water as a solvent and "polyglycerol polyglycidyl ether (manufactured by Nagase ChemteX Corp.)" A composition consisting of 10% by mass was used.

<Adhesive resin layer (thickness 15 μm)>
The mixture of the following materials was mixed and used so that it might be set to AR-1: AR-2: AR-3 3: 1: 1 by mass ratio.
(AR-1): A random polypropylene (PP) -based acid-modified polypropylene resin composition (manufactured by Mitsui Chemicals, Inc.) containing ethylene-propylene rubber was used as an incompatible rubber.
(AR-2): Polypropylene having an atactic structure or a propylene-α-olefin copolymer having atactic structure (manufactured by Sumitomo Chemical Co., Ltd., “Tuffselenium H”) was used.
(AR-3): A propylene-α-olefin copolymer having an isotactic structure (manufactured by Mitsui Chemicals, Inc., “Tafmer XM”) was used.

<Second adhesive layer (thickness 5 μm)>
An adhesive was used in which a polyisocyanate compound having an isocyanurate structure was blended at 10 parts by mass (solid content ratio) with respect to 100 parts by mass of a maleic anhydride-modified polyolefin resin dissolved in toluene.

<Sealant layer>
The resin composition (SL-1-SL-12) which mixed each component shown to following Table 1 by the compounding quantity (unit: mass part) shown to the same table was used. The details of each component are shown below.
(A) Component (random PP): Propylene-ethylene random copolymer having a melting point of 140 ° C. (Prime Polymer Co., Ltd., “Prime Polypro”).
Component (B-1) (Propylene-butene-1): Propylene-butene-1 random copolymer elastomer having a melting point of 85 ° C. having compatibility with the component (A) (manufactured by Mitsui Chemicals, "Tafmer XM" ).
Component (B-2) (Ethylene-butene-1): Ethylene-butene-1 random copolymer elastomer having a melting point of 75 ° C. not having compatibility with the component (A) (manufactured by Sumitomo Chemical Co., Ltd., “EXCELLEN ").
Hydrogenated styrenic rubber: A hydrogenated styrenic thermoplastic elastomer ("TAFTEC" manufactured by Asahi Kasei Corp.) having compatibility with the component (A).
Ethylene-propylene: An ethylene-propylene copolymer elastomer ("Tafmer A" manufactured by Mitsui Chemicals, Inc.) which is not compatible with the component (A).

Example 1
First, the first corrosion prevention treatment layer was provided on the metal foil layer in the following procedure. That is, (CL-1) was coated on one surface of the metal foil layer by microgravure coating so as to have a dry coating amount of 70 mg / m ^2, and was baked at 200 ° C. in a drying unit. Next, (CL-2) is applied on the obtained layer by microgravure coating so as to have a dry coating amount of 20 mg / m ^2, and it consists of (CL-1) and (CL-2). The composite layer was formed as a first anticorrosion treatment layer. This composite layer is a layer in which two types of (CL-1) and (CL-2) are combined to exhibit corrosion prevention performance.

Next, (CL-1) was coated on the other surface of the metal foil layer by microgravure coating so as to have a dry coating amount of 70 mg / m ^2, and was baked at 200 ° C. in a drying unit. Next, (CL-3) is applied on the obtained layer by microgravure coating so as to have a dry coating amount of 20 mg / m ² , thereby comprising (CL-1) and (CL-3) The composite layer was formed as a second corrosion prevention treatment layer. This composite layer is a layer in which two types of (CL-1) and (CL-3) are combined to exhibit corrosion prevention performance.

  Next, the first anti-corrosion treated layer side of the metal foil layer provided with the first and second anti-corrosion treated layers is coated with a polyurethane adhesive (first adhesive layer) by a dry lamination method. It stuck to the material layer. The adhesive resin layer (thickness 15 μm) and the sealant layer (thickness: 15 μm) are set by setting this in the unwinding part of the extrusion laminating machine and co-extruding on the second corrosion prevention treated layer under processing conditions of 290 ° C. and 100 m / min. 30 μm thick). In addition, the adhesive resin layer and the sealant layer produced the compound of various materials beforehand using the twin-screw extruder, and were used for the said extrusion lamination through the process of water cooling and pelletizing. The resin composition (SL-1) was used for formation of a sealant layer.

  The laminate obtained in this manner is heat-treated by thermal lamination so that the highest attainable temperature of the laminate is 190 ° C., and the sheath material of Example 1 (base layer / first adhesive A layer / layer of first anticorrosion treatment layer / metal foil layer / second anticorrosion treatment layer / adhesive resin layer / adhesive layer) was manufactured.

[Examples 2 to 7]
The same as Example 1, except that the resin composition used to form the sealant layer was changed to (SL-2) to (SL-7) (all 30 μm thick), the conditions of Examples 2 to 7 were obtained. The exterior material was manufactured.

[Example 8]
In the same manner as in Example 1, a laminate of base material layer / first adhesive layer / first anticorrosion treatment layer / metal foil layer / second anticorrosion treatment layer was produced. Next, an adhesive (second adhesive layer) is applied at a dry coating amount of 4 to 5 g / m ² on the second corrosion prevention treated layer by a dry lamination method, dried and formed. After the membrane, a sealant layer was applied. The sealant layer was formed into a film with a thickness of 45 μm using a resin composition (SL-1), and an unstretched cast film in which an adhesive bonding surface was subjected to a corona treatment was used. Thereafter, aging is carried out at 40 ° C. for 5 days, and the exterior material of Example 8 (base material layer / first adhesive layer / first corrosion prevention treatment layer / metal foil layer / second corrosion prevention treatment layer / A second adhesive layer / sealant layer laminate was produced.

Comparative Examples 1 to 5
Comparative Examples 1 to 5 were carried out in the same manner as Example 1, except that the resin composition used to form the sealant layer was changed to (SL-8) to (SL-12) (each 30 μm thick). The exterior material was manufactured.

<Evaluation>
The following evaluation test was done with respect to the exterior material obtained by the Example and the comparative example.

(Electrolyte solution laminate strength)
An electrolytic solution prepared by adding LiPF ₆ to 1 M in a mixed solution of ethylene carbonate / diethyl carbonate / dimethyl carbonate = 1/1/1 (mass ratio) is filled in a Teflon (registered trademark) container, and the outer packaging material is filled therein. The sample was cut into pieces of 15 mm × 100 mm and sealed, and stored at 85 ° C. for 24 hours. Then, it was co-washed, and laminate strength (T-type peel strength) between metal foil layer / adhesive resin layer or metal foil layer / second adhesive layer was measured using a testing machine (manufactured by INSTRON). The test was conducted at a peeling speed of 50 mm / min in an atmosphere of 23 ° C. and 50% RH according to JIS K6854. Based on the results, the following criteria were evaluated.
A: Lamination strength is more than 12 N / 15 mm B: Lamination strength is 10 N / 15 mm or more, 12 N / 15 mm or less C: Lamination strength is 6 N / 15 mm or more, less than 10 N / 15 mm D: Lamination strength is less than 6 N / 15 mm

(Electrolyte heat seal strength)
A sample obtained by cutting the package to 60 mm × 120 mm was folded into two, and one side was heat sealed at 190 ° C., 0.5 MPa, 3 sec with a seal bar of 10 mm width. After that, add LiPF ₆ to the mixed solution of ethylene carbonate / diethyl carbonate / dimethyl carbonate 1/1/1/1 (mass ratio) to 1 M in the remaining two sides also heat sealed and bag-like exterior material After storing the pouch in which 1 ml of the electrolyte solution was injected for 24 hours at 60 ° C., the heat sealed first side was cut to a width of 15 mm (see FIG. 3), and the seal strength (T-type peel strength) was tested using a tester (INSTRON). Measurement). The test was conducted at a peeling speed of 50 mm / min in an atmosphere of 23 ° C. and 50% RH according to JIS K6854. Based on the results, the following criteria were evaluated.
A: Seal strength is 100 N / 15 mm or more, burst width is more than 10 mm B: Seal strength is 100 N / 15 mm or more, burst width is 5 to 10 mm
C: Seal strength is 80 N / 15 mm or more, less than 100 N / 15 mm D: Seal strength is less than 80 N / 15 mm

(Seal appearance)
In the above evaluation of the electrolyte heat seal strength, in the seal portion (strength measurement portion in FIG. 3) after heat sealing at 190 ° C., 0.5 MPa, 3 seconds, excessive seal on the inner layer sealant side other than the portion in contact with the seal bar I confirmed that there was no part. Based on the results, the following criteria were evaluated. The over-sealed portion may possibly cause a thin seal or may reduce the internal volume of the cell body, which may affect the cell performance and insulation. Therefore, it is preferable that there is no over-sealed portion.
A: There was no oversealed part, and it was a uniform sealed part D: There was oversealed part

(Degassing heat seal strength)
The outer packaging material is cut into a size of 75 mm × 150 mm and folded in two into 37.5 mm × 150 mm (see FIG. 4A), and then the 150 mm side and the 37.5 mm side are heat sealed to form a bag. Thereafter, 5 ml of an electrolyte prepared by adding 1 M of LiPF ₆ to a mixed solution of ethylene carbonate / diethyl carbonate / dimethyl carbonate = 1/1/1 (mass ratio) was poured into the pouch, and heat sealed. After sealing and storing for 24 hours at 60 ° C., the pouch central portion was heat-sealed at 190 ° C., 0.3 MPa and 2 sec for 2 seconds (see FIG. 4 (b)). After 24 hours of storage at room temperature, the degashing seal is cut to a width of 15 mm to stabilize the seal (see Fig. 4 (c)), and the heat seal strength (T-shaped peel strength) is tested using a tester. It measured using (made by INSTRON). The test was conducted at a peeling speed of 50 mm / min in an atmosphere of 23 ° C. and 50% RH according to JIS K6854. Based on the results, the following criteria were evaluated.
A: Seal strength 80 N / 15 mm or more B: Seal strength 60 N / 15 mm or more, less than 80 N / 15 mm C: Seal strength 40 N / 15 mm or more, less than 60 N / 15 mm D: Seal strength less than 40 N / 15 mm

(Molding whitening)
A normal sample of the exterior material and a sample stored for 1 week at 60 ° C. are cut into 120 mm × 200 mm, and set in a cold forming mold so that the sealant layer is in contact with the convex part of the forming machine. A 5 mm deep drawing was performed in sec. Thereafter, whitening of the side on the side of the film holding portion where the stretching was most severe was observed. As the mold, one having a molding area of 80 mm × 70 mm (square cylinder type) and a punch corner radius (RCP) of 1.0 mm was used. Based on the results, the following criteria were evaluated. If the evaluation is C or more, it can be said that there is no problem in practical use.
A: Both normal samples and samples stored at 60 ° C. for 1 week without whitening B: Normal samples without whitening, samples stored at 60 ° C. for 1 week stored light whitening C: Normal samples with light whitening, 60 ° C. stored for 1 week Whitening with sample D: Whitening with normal sample

(Total quality)
The results of the above evaluations are shown in Table 2. In Table 2 below, it can be said that the overall quality is excellent when the evaluation results do not have D evaluation.

  As is clear from the results shown in Table 2, the sheathing materials of Examples 1 to 8 in which (SL-1) to (SL-7) were used as the resin composition for forming the sealant layer had molded whitening and seal appearance It was confirmed that the laminate strength and the seal strength (the electrolyte laminate strength, the electrolyte heat seal strength and the degassing heat seal strength) to which the electrolyte participates are improved while being good. On the other hand, it was confirmed that the exterior materials of Comparative Examples 1, 4 and 5 are excellent in molded whitening and seal appearance but inferior in laminate strength and seal strength in which the electrolytic solution is involved. Moreover, it was confirmed that the exterior materials of Comparative Examples 2 and 3 are inferior in molded whitening or seal appearance although the laminate strength and seal strength involving the electrolytic solution are good.

  DESCRIPTION OF SYMBOLS 10, 20 ... Outer package material for electrical storage apparatuses, 11 ... Base material layer, 12 ... 1st adhesive bond layer, 13 ... Metal foil layer, 14 ... Corrosion prevention processing layer, 15 ... Adhesive resin layer, 16 ... Sealant layer, 17 Second adhesive layer.

Claims (9)

At least a base material layer, a first adhesive layer, a metal foil layer provided with a corrosion prevention treatment layer on one or both surfaces, a second adhesive layer or adhesive resin layer, and a sealant layer in this order An exterior material for a power storage device having a stacked structure,
The sealant layer comprises 60 to 95% by mass of (A) a propylene-ethylene random copolymer, and 5 to 40% by mass of a polyolefin-based elastomer having a melting point of 150 ° C. or less having (B) butene-1 as a comonomer. An exterior material for a power storage device, which is a layer formed of a resin composition containing the same.   (B) A compatible polyolefin-based elastomer in which the (B) polyolefin-based elastomer is compatible with the (A) propylene-ethylene random copolymer, and the (A) propylene-ethylene random copolymer The packaging material for a storage battery according to claim 1, comprising (B-2) an incompatible polyolefin-based elastomer which is not compatible with the above.   The (B-1) compatible polyolefin-based elastomer is a propylene-butene-1 random copolymer, and the (B-2) non-compatible polyolefin-based elastomer is an ethylene-butene-1 random copolymer An exterior material for a power storage device according to claim 2. The metal foil layer and the sealant layer are laminated via the adhesive resin layer,
The packaging material for a storage battery device according to any one of claims 1 to 3, wherein the adhesive resin layer contains modified polypropylene as the adhesive resin composition. The metal foil layer and the sealant layer are laminated via the adhesive resin layer,
The exterior for a storage battery device according to any one of claims 1 to 4, wherein the adhesive resin layer contains an adhesive resin composition and a polypropylene having an atactic structure or a propylene-α-olefin copolymer having an atactic structure. Material.   The packaging material for a storage battery device according to claim 5, wherein the adhesive resin layer further contains a propylene-α-olefin copolymer having an isotactic structure. The corrosion prevention treatment layer is provided at least on the sealant layer side of the metal foil layer, and the corrosion prevention treatment layer includes at least one polymer selected from the group consisting of a cationic polymer and an anionic polymer,
The metal foil layer and the sealant layer are laminated via the second adhesive layer,
The said 2nd adhesive bond layer contains the compound which has the reactivity with the said polymer contained in the said corrosion prevention treatment layer which contact | connects the said 2nd adhesive bond layer as described in any one of Claims 1-3. Storage material for power storage device.   The exterior material for a storage battery device according to claim 7, wherein the second adhesive layer contains an acid-modified polyolefin resin.   The said corrosion prevention treatment layer is a rare earth element oxide, 1-100 mass parts phosphoric acid or phosphate with respect to 100 mass parts of this rare earth element oxide, Any one of Claims 1-8 An exterior material for a power storage device according to claim 1.

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