Battery packaging material

Abstract

To improve adhesive strength at high temperatures of a battery packaging material using an active energy-curable adhesive.SOLUTION: In a battery packaging material 1, a heat-resistant resin layer 13 is bonded to one surface of a barrier layer 11 via a first adhesive layer 12, and a sealant layer 15 is bonded to the other surface via a second adhesive layer 14. The first adhesive layer 12 is composed of an adhesive composition containing a polyester polyurethane acrylate (A) and a (meth)acrylate monomer (B) having an isobornyl group at a mass ratio of (A) / (B)=1 / 1-8 / 1.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a battery packaging material and related technologies that are suitably used as a case for secondary batteries, for example, for in-vehicle, stationary, notebook computers, mobile phones, and cameras, in particular, for small portable lithium ion secondary batteries. [Background technology]

[0002] Energy storage devices, such as lithium-ion secondary batteries, can now be made into a variety of shapes, from cans and cases to laminate-type packaging materials in which a resin layer is bonded to both sides of metal foil such as aluminum, making it possible to make them thinner and lighter.

[0003] Laminate-type battery packaging materials are known in which a resin film for a heat-resistant resin layer that will become the outer surface of the case is bonded to one side of a metal foil with an adhesive, and a resin film for a sealant layer is bonded to the other side with an adhesive, and a variety of adhesives are used.

[0004] In conventional battery packaging materials, a two-component curing urethane adhesive was generally used to bond the metal foil and the resin film for the heat-resistant resin layer, but this required a heat aging process of 7 to 9 days for curing, which resulted in poor productivity and required large aging rooms, resulting in high equipment costs. For this reason, a battery packaging material has been proposed that uses an electron beam curing adhesive instead of a two-component curing urethane adhesive, eliminating the heat aging process and significantly shortening the curing time, and thus eliminating the need for large equipment (see Patent Document 1). [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent No. 5704298 Summary of the Invention [Problem to be solved by the invention]

[0006] The battery packaging material described in Patent Document 1 has improved productivity because the adhesive hardens in a short time by electron beam irradiation. However, the battery packaging material has a problem in that delamination (peeling) is likely to occur between the metal foil and the heat-resistant resin layer that forms the outer surface of the case when deep molding is performed when making a battery case. There is also a problem in that delamination is likely to occur between the metal foil and the heat-resistant resin layer when heat sealing the battery case or when the battery is used under harsh conditions such as high temperature and humidity. [Means for solving the problem]

[0007] In view of the above-mentioned background art, an object of the present invention is to improve the adhesive strength at high temperatures in a battery packaging material using an electron beam curable adhesive that cures in a short time.

[0008] That is, the present invention has the configurations described in the following [1] to [7].

[0009] [1] A battery packaging material in which a heat-resistant resin layer is bonded to one surface of a barrier layer via a first adhesive layer, and a sealant layer is bonded to the other surface of the barrier layer via a second adhesive layer, The battery packaging material, characterized in that the first adhesive layer is composed of an adhesive composition containing a polyester polyurethane acrylate (A) and a (meth)acrylate monomer (B) having an isobornyl group in a mass ratio of (A) / (B)=1 / 1 to 8 / 1.

[0010] [2] The battery packaging material according to the preceding paragraph 1, wherein the adhesive composition contains two or more polyester polyurethane acrylates (A) having different glass transition temperatures, and at least one of the polyester polyurethane acrylates (A) has a glass transition temperature of 40°C or lower.

[0011] [3] The battery packaging material according to item 1 or 2, wherein the adhesive composition further contains at least one of an epoxy resin (C), an alkoxysilyl group-containing radically polymerizable compound (D), a phosphate group-containing (meth)acrylate (E), and a photocationic polymerization initiator (F).

[0012] [4] The battery packaging material according to item 1 or 2, wherein the adhesive composition further contains at least one of 1 mass % to 10 mass % of an epoxy resin (C), 0.1 mass % to 5 mass % of an alkoxysilyl group-containing radically polymerizable compound (D), 0.1 mass % to 5 mass % of a phosphate group-containing (meth)acrylate (E), and 0.1 mass % to 5 mass % of a photocationic polymerization initiator (F).

[0013] [5] The packaging material for batteries according to any one of items 1 to 4 above, wherein an undercoat layer is formed on at least a surface of the barrier layer facing the heat-resistant resin layer.

[0014] [6] A battery case, characterized in that the battery packaging materials according to any one of items 1 to 5 above are joined together with their sealant layers facing inward, and the edges are heat-sealed to form a battery element chamber for accommodating a battery element.

[0015] [7] A secondary battery comprising a battery element housed in a battery element chamber of the battery case described in paragraph 6 above. Effect of the Invention

[0016] In the battery packaging material described in [1] above, the first adhesive layer for bonding the barrier layer and the heat-resistant resin layer is composed of an adhesive composition containing a polyester polyurethane acrylate (A) and a (meth)acrylate monomer (B) having an isobornyl group in a specified ratio, and therefore can be cured in a short time by irradiation with active energy rays and has excellent adhesion and heat resistance. Therefore, delamination between the barrier layer and the heat-resistant resin layer is prevented during heat sealing when sealing the battery case or when the battery is used in a high-temperature environment.

[0017] According to the battery packaging material described in [2] above, the adhesive composition contains two or more types of polyester polyurethane acrylate (A) having different glass transition temperatures, and at least one of the polyester polyurethane acrylates has a glass transition temperature of 40°C or lower, so that the first adhesive layer can have both good adhesion and heat resistance.

[0018] According to the battery packaging material described in the above items [3] and [4], the heat resistance and adhesiveness are further improved.

[0019] According to the battery packaging material described in [5] above, the undercoat layer enhances the adhesion between the barrier layer and the heat-resistant resin layer, improving the delamination prevention effect.

[0020] The battery case described in [6] above is made of the battery packaging material described in [1] above, and therefore delamination during heat sealing is prevented.

[0021] The battery described in [7] above uses the battery case described in [6] above, and therefore delamination during use in a high-temperature environment is prevented. [Brief description of the drawings]

[0022] [Figure 1] FIG. 1 is a cross-sectional view showing an example of the battery packaging material of the present invention. [Diagram 2] FIG. 2 is a cross-sectional view showing another example of the battery packaging material of the present invention. [Diagram 3] FIG. 3 is a cross-sectional view of a battery case made from the battery packaging material of FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0023] FIG. 1 shows one embodiment of the battery packaging material of the present invention.

[0024] The battery packaging material 1 has a heat-resistant resin layer 13 bonded to one surface of a barrier layer 11 via a first adhesive layer 12, and a sealant layer 15 bonded to the other surface via a second adhesive layer 14.

[0025] As shown in Fig. 3, a battery case 50 is produced by placing a molded container 51 and a cover plate 52 using the battery packaging material 1 with their sealant layers 15 facing each other and heat-sealing the edges. A battery 60 is produced by sealing a battery element 55 in a battery element chamber 54 of the battery case 50. In the produced battery case 50, the heat-resistant resin layer 13 is the outer layer and the sealant layer 15 is the inner layer. In the present invention, when describing the positions of the layers constituting the battery packaging material 1 in terms of directions, the direction of the heat-resistant resin layer 13 is referred to as the outer side and the sealant layer 15 is referred to as the inner side.

[0026] The present invention specifies an adhesive composition that constitutes the first adhesive layer 12 between the barrier layer 11 and the heat-resistant resin layer 13 of the battery packaging material 1 . [Main components of the first adhesive layer] The adhesive composition constituting the first adhesive layer 1 must contain polyester polyurethane acrylate (A) and a (meth)acrylate monomer (B) having an isobornyl group in a mass ratio of (A) / (B)=1 / 1 to 8 / 1. The adhesive composition is cured by irradiation with active energy to strongly bond the barrier layer 11 and the heat-resistant resin layer 13.

[0027] The number of functional groups of the acryloyl group in the molecule of the polyester polyurethane acrylate (A) is not particularly limited, but is preferably 2 or more, more preferably 2 to 4, from the viewpoint of adhesion between substrates. When the number of acryloyl groups is less than 2, the crosslink density after curing is low, so that the adhesiveness and heat resistance are weakened, and the practical use is reduced. When the number of functional groups of the (meth)acryloyl group is more than 4, the crosslink density is high, so that the adhesiveness is weakened. In addition, the number average molecular weight is not particularly limited, but is preferably in the range of 4000 to 30000. When the number average molecular weight is less than 4000, the flexibility is lost and the adhesiveness is weakened because the molecular weight between crosslinks is low. When the number average molecular weight exceeds 30000, the viscosity is high and the coating suitability is reduced, so that it is not practical. In addition, when the molecular weight between crosslinks is high, the material becomes too soft after curing, so that the adhesiveness is weakened. The number average molecular weight in the present invention is measured by gel permeation chromatography (GPC).

[0028] The (meth)acrylate monomer (B) having an isobornyl group has the effect of improving the heat resistance of the cured film of the active energy curable adhesive composition by reducing the degree of freedom of atomic vibration and inhibiting molecular motion due to its ring structure, and the improvement in heat resistance of the first adhesive layer 12 prevents delamination of the barrier layer 11 and the heat-resistant resin layer 13. Examples of the (meth)acrylate monomer (B) having an isobornyl group include isobornyl acrylate and isobornyl methacrylate.

[0029] The polyester polyurethane acrylate (A) and the (meth)acrylate monomer (B) having an isobornyl group are mixed at a mass ratio of (A) / (B)=1 / 1 to 8 / 1 to obtain an adhesive composition having excellent adhesion and heat resistance. If the amount of polyester polyurethane acrylate (A) is less than (A) / (B)=1 / 1, the flexibility of the cured film decreases and the adhesiveness becomes weak. If the amount of polyester polyurethane (meth)acrylate (A) is more than (A) / (B)=8 / 1, the cured film becomes too soft and the heat resistance becomes weak. The preferred ratio (A) / (B) is 1 / 1 to 6 / 1.

[0030] The polyester polyurethane acrylate (A) does not need to be one type, and two or more different types can be mixed and used. When two or more types are used, at least one of them is preferably a polyester polyurethane acrylate (A) having a glass transition temperature (Tg) of 40° C. or less, and by using a polyester polyurethane acrylate (A) having a low glass transition temperature (Tg), both adhesiveness and heat resistance can be achieved.

[0031] In addition, when two or more types are used, all of the types may be polyester polyurethane acrylates (A) having a glass transition temperature (Tg) of 40°C or less, or polyester polyurethane acrylates (A) having a glass transition temperature (Tg) of more than 40°C may be used together with polyester polyurethane acrylates (A) having a glass transition temperature (Tg) of 40°C or less.

[0032] In the following description, polyester polyurethane acrylate (A) having a glass transition temperature (Tg) of 40° C. or lower is referred to as polyester polyurethane acrylate (A1), and polyester polyurethane acrylate (A) having a glass transition temperature (Tg) of more than 40° C. is referred to as polyester polyurethane acrylate (A2).

[0033] When the polyester polyurethane acrylate (A1) and the polyester polyurethane acrylate (A2) are used in combination, the amount of the polyester polyurethane acrylate (A2) is preferably 75 parts by mass or less per 100 parts by mass of the polyester polyurethane acrylate (A1). If the amount of the polyester polyurethane acrylate (A2) exceeds 75 parts by mass, the flexibility of the cured first adhesive layer 12 may decrease, resulting in a decrease in the adhesion between the barrier layer 11 and the heat-resistant resin layer 13. The particularly preferred amount of the polyester polyurethane acrylate (A2) is 20 parts by mass to 60 parts by mass per 100 parts by mass of the polyester polyurethane acrylate (A1).

[0034] The polyester polyurethane acrylate (A) can be obtained by reacting a polyester polyol (a-1) of the polyol component with an isocyanate compound (a-2) and a hydroxy (meth) acrylate (a-3). The following starting materials and synthesis method are common regardless of the glass transition temperature (Tg).

[0035] The polyester polyol (a-1) may be, for example, a polybasic acid component such as isophthalic acid, terephthalic acid, naphthalenedicarboxylic acid, phthalic anhydride, succinic acid, adipic acid, azelaic acid, sebacic acid, maleic acid, fumaric acid, itaconic acid, or anhydrides thereof, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, tetrabromophthalic anhydride, tetrachlorophthalic anhydride, HET anhydride, or HIMIC anhydride, either alone or in combination with, for example, ethylene glycol, propylene glycol, diethylene glycol, dipropylene glycol, neopentyl glycol, triethylene glycol, tripropylene glycol, tetramethyl phthalic anhydride ... It can be obtained by dehydration condensation of polyhydric alcohol components such as ethylene glycol, polyethylene glycol, polypropylene glycol, polytetramethylene ether glycol, 1,3-butylene glycol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,9-nonanediol, 2-methyl-1,8-octanediol, hydrogenated bisphenol A, glycerin, trimethylolethane, trimethylolpropane, trishydroxymethylaminomethane, pentaerythritol, polyether polyol, polycarbonate polyol, acrylic polyol, and polyurethane polyol, either alone or in combination.

[0036] The polyol component may be used in combination with a polyol other than the polyester polyol (a-1). For example, low molecular weight polyols such as 1,6-hexanediol and trimethylolpropane, polyether polyols, acrylic polyols, and polyurethane polyols may be used alone or in combination of two or more.

[0037] Examples of the isocyanate compound (a-2) include 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 1,3-xylylene diisocyanate, 1,4-xylylene diisocyanate, 1,5-naphthalene diisocyanate, 1,3-phenylene diisocyanate, 1,4-phenylene diisocyanate, 3,3'-dimethylphenylene diisocyanate, 1,6-hexamethylene diisocyanate, isophorone diisocyanate, 4,4'-methylenebis(cyclohexyl isocyanate), 2,2,4-trimethylhexa Examples of polyfunctional polyisocyanate compounds include their biuret derivatives, nurate derivatives, and trimethylolpropane adducts. Examples of isocyanate compounds having a (meth)acryloyl group include 2-isocyanatoethyl (meth)acrylate, 2-(2-methacryloyloxyethyloxy)ethyl isocyanate, and 1,1-(bisacryloyloxymethyl)ethyl isocyanate. These can be used alone or in combination of two or more.

[0038] Examples of the hydroxy(meth)acrylate (a-3) include compounds having one (meth)acryloyl group, such as 2-hydroxyethyl(meth)acrylate, 2-hydroxypropyl(meth)acrylate, 2-hydroxybutyl(meth)acrylate, 4-hydroxybutyl(meth)acrylate, 2-hydroxy-3-phenoxypropyl(meth)acrylate, 1,5-pentanediol mono(meth)acrylate, 1,6-hexanediol mono(meth)acrylate, cyclohexanedimethanol mono(meth)acrylate, polyether-modified hydroxyethyl(meth)acrylate, and caprolactone-modified hydroxyethyl. (meth)acrylates, etc., and examples of compounds having two or more acryloyl groups include trimethylolpropane di(meth)acrylate, trimethylolethane di(meth)acrylate, pentaerythritol di(meth)acrylate, pentaerythritol tri(meth)acrylate, dipentaerythritol di(meth)acrylate, dipentaerythritol tri(meth)acrylate, dipentaerythritol tetra(meth)acrylate, dipentaerythritol penta(meth)acrylate, 2-hydroxy-3-acryloyloxypropyl(meth)acrylate, etc., which can be used alone or in combination of two or more. In addition, in consideration of the reaction rate during synthesis, compounds having a primary hydroxyl group are preferred, and among them, 2-hydroxyethyl(meth)acrylate is particularly preferred.

[0039] The synthesis of the polyester polyurethane acrylate (A) can be carried out in a solvent as necessary. Examples of these solvents include hydrocarbons other than alcohols, acetates, and ketones, and from the viewpoint of coating workability, ethyl acetate and methyl ethyl ketone are preferred. In addition, known reaction accelerators can be used in the synthesis of the polyester polyurethane acrylate (A), and examples of reaction accelerators include metal catalysts such as dibutyltin diacetate, dibutyltin dilaurate, dioctyltin dilaurate, and dibutyltin dimaleate, tertiary amines such as 1,8-diazabicyclo(5,4,0)undecene-7 and 1,5-diazabicyclo(4,3,0)-nonene-5, and reactive tertiary amines such as triethanolamine.

[0040] The adhesive composition may contain a polyisocyanate or an isocyanate compound (X) having a radical polymerizable unsaturated bond that is not a component of polyester polyurethane acrylate as a component for enhancing adhesion. By adding the isocyanate compound (X), the cohesive force is increased by the reaction between the hydroxyl group of the adhesive cured product and the moisture attached to the barrier layer 11 and heat-resistant resin layer 13 to be bonded and the isocyanate group, thereby obtaining excellent adhesion. However, if the isocyanate compound is added in an amount of more than 25% by mass, the curing time may be extended, or carbon dioxide gas may be generated by the reaction of isocyanate with water such as moisture, which may cause bubbles in the adhesive layer, so that the proportion of the isocyanate compound in the adhesive composition is preferably 25% by mass or less. Note that the isocyanate compound (X) shown here is not a component of polyester polyurethane acrylate (A).

[0041] The adhesive composition is cured by irradiation with active energy rays such as ultraviolet rays, X-rays, visible light, α-rays, β-rays, γ-rays, and EB (electron beam), to form a first adhesive 12, which bonds the barrier layer 11 and the heat-resistant resin layer 13. The first adhesive layer 12, which is a cured film of the adhesive composition, has high heat resistance, and the bonding strength between the barrier layer 11 and the heat-resistant resin layer 13 is high even at high temperatures, making it possible to prevent delamination during heat sealing. [Auxiliary components in the first adhesive layer] In addition to the components described above, the adhesive composition may optionally contain at least one of the auxiliary components (C) to (F) below.

[0042] The epoxy resin (C) is a component that contributes to improving the heat resistance of the first adhesive layer 12.

[0043] The epoxy resin is a general term for resins having an epoxy group in the molecule and epoxy (meth)acrylates obtained by modifying resins having an epoxy group in the molecule and adding a (meth)acryloyl group in the molecule.Specific examples include bisphenol A type epoxy resins, bisphenol F type epoxy resins, alicyclic epoxy resins, novolac type epoxy resins, and epoxy acrylates. For example, bisphenol A type epoxy resins include those manufactured by Mitsubishi Chemical Corporation (jER825, jER827, jER828, jER1001, jER1002, jER1003, jER1004, jER1032H60), bisphenol F type epoxy resins include those manufactured by Mitsubishi Chemical Corporation (jER4004P, jER4005P), alicyclic epoxy resins include those manufactured by Daicel Corporation (Celloxide 2021P, Celloxide 2081, Epolead GT401), novolac type epoxy resins include those manufactured by DIC Corporation (EPICLON N-660, EPICLON N-740), and epoxy acrylates include those manufactured by Daicel-Allnex Corporation (EBECRYL600, EBECRYL3603, EBECRYL3700). These can be used alone or in combination of two or more kinds.

[0044] The content of the epoxy resin (C) in the adhesive composition is preferably 0.1% by mass to 10% by mass. If the content of the epoxy resin (C) exceeds 10% by mass, the adhesive property may decrease.

[0045] The alkoxysilyl group-containing radically polymerizable compound (D) is a component that contributes to improving the barrier layer 11, that is, the adhesion to metal materials.

[0046] The alkoxysilyl group-containing radical polymerizable compound (D) is not particularly limited as long as it is a radical polymerizable compound having an alkoxysilyl group in the molecule. For example, vinyltrimethoxysilane, vinyltriethoxysilane, vinyltributoxysilane, allyltrimethoxysilane, 3-(meth)acryloxypropyltrimethoxysilane, 3-(meth)acryloxypropyltriethoxysilane, p-styryltrimethoxysilane, p-styryltrimethoxysilane, or organosiloxane obtained by condensing these alone or two or more kinds thereof, etc. can be mentioned, and these can be used alone or two or more kinds can be used in combination.

[0047] The content of the alkoxysilyl group-containing radically polymerizable compound (D) in the adhesive composition is preferably 0.1% by mass to 5% by mass. If it exceeds 5% by mass, there is a risk of the adhesiveness and heat resistance decreasing.

[0048] The phosphate group-containing (meth)acrylate (E) contributes to improving the barrier layer 11, that is, the adhesion to the metal material.

[0049] The phosphate group-containing (meth)acrylate (E) can be used alone or in combination with a phosphorus compound not containing a (meth)acryloyl group, but the phosphate group-containing (meth)acrylate (E) participating in a crosslinking reaction is more preferred because it provides superior adhesion and durability. Examples of the phosphate group-containing (meth)acrylate (E) include 2-(meth)acryloyloxyethyl acid phosphate and bis(2-(meth)acryloyloxyethyl)-acid phosphate, such as those manufactured by Kyoeisha Chemical Co., Ltd. (Light Ester P-1M, Light Ester P-2M, Light Acrylate P-1A) and those manufactured by BASF (Laromer PA9083). These may be used alone or in combination of two or more kinds.

[0050] The content of the phosphate group-containing (meth)acrylate (E) in the adhesive composition is preferably 0.1% by mass to 5% by mass. If it exceeds 5% by mass, the adhesive property and heat resistance may decrease.

[0051] The photocationic polymerization initiator (F) is used as a polymerization initiator for the epoxy resin (C) and the alkoxysilyl group-containing radically polymerizable compound (D).

[0052] The photocationic polymerization initiator (F) is an ionic onium salt such as an aromatic sulfonium salt or an aromatic iodonium salt consisting of a cationic moiety and an anionic moiety, and examples thereof include those manufactured by IGM Resins BV (Omnicat250, Omnicat270), ADEKA Corporation (ADEKA Optomer SP series), and San-Apro Ltd. (CPI-100P, CPI-101A).

[0053] The content of the photocationic polymerization initiator (F) in the adhesive composition is preferably 0.1% by mass to 5% by mass from the viewpoint of reactivity.

[0054] Furthermore, the adhesive composition may contain, as necessary, coloring pigments, extender pigments, dyes, tackifiers, dispersants, defoamers, wetting agents, antistatic agents, thickeners, antioxidants, ultraviolet absorbers, radical scavengers, and the like, provided that the performance of the adhesive composition is not impaired.

[0055] The adhesive composition is cured instantly when irradiated with active energy rays, and a photoradical polymerization initiator may be added to improve the curing properties.

[0056] The photoradical polymerization initiator may be benzophenone, 2,2-dimethoxy-1,2-diphenylethane-1-one, 1-hydroxy-cyclohexyl-phenyl-ketone, 2-hydroxy-2-methyl-1-phenyl-propan-1-one, 1-[4-(2-hydroxyethoxy)-phenyl]-2-hydroxy-2-methylpropan-1-one, 2-hydroxy-1-{4-[4-(2-hydroxy-2-methyl-propionyl)-benzyl]-phenyl}-2-methyl-propan-1-one, phenyl glyoxylic acid methyl ester, 2-methyl-1-[4-(methylthio)phenyl]-2-morpholinopropane- 1-one, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butan-1-one, 2-dimethylamino-2-(4-methyl-benzyl)-1-(4-morpholin-4-yl-phenyl)-butan-1-one, bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide, 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide, 1,2-octanedione, ethanone, 1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazol-3-yl]-, 1-(O-acetyloxime), etc., which can be used alone or in combination of two or more.

[0057] The adhesive composition can be diluted with a solvent such as a hydrocarbon, an acetate, a ketone, or an alcohol to adjust the viscosity according to the coating method or the specifications of the coating machine. From the viewpoint of coating workability, ethyl acetate or methyl ethyl ketone is preferred.

[0058] Furthermore, in order to adjust the viscosity of the adhesive composition in accordance with the coating method and the specifications of the coating machine, a reactive diluent having radical polymerizability can be used within a range that does not impair the performance.

[0059] Examples of the reactive diluent include monofunctional (meth)acrylates such as 4-t-butylcyclohexyl (meth)acrylate, 2-(2-ethoxyethoxy)ethyl (meth)acrylate, stearyl (meth)acrylate, diethylene glycol monobutyl ether (meth)acrylate, tetrahydrofurfuryl (meth)acrylate, lauryl (meth)acrylate, isooctyl (meth)acrylate, tridecyl (meth)acrylate, isobornyl (meth)acrylate, and myristyl (meth)acrylate; 1,3-butylene glycol diacrylate, 1,4-butanediol di(meth)acrylate, and the like. Examples of such acrylates include bifunctional (meth)acrylates such as ethylene glycol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, neopentyl glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, and tripropylene glycol di(meth)acrylate; and polyfunctional (meth)acrylates such as trimethylolpropane tri(meth)acrylate, ethoxylated (3) trimethylolpropane tri(meth)acrylate, and propoxylated (3) glyceryl tri(meth)acrylate. These may be used alone or in combination of two or more. [Other layers] In the battery packaging material of the present invention, well-known materials can be appropriately used for the layers other than the first adhesive layer 12, and there are no particular limitations on the lamination method. Preferred materials for the layers other than the first adhesive layer 12 are described below. (Heat-resistant resin layer) The heat-resistant resin layer 13 is made of a heat-resistant resin film that does not melt at the heat-sealing temperature when the battery packaging material 1 is heat-sealed. The heat-resistant resin is a heat-resistant resin having a melting point 10°C or higher, preferably 20°C or higher, than the melting point of the resin constituting the sealant layer 15. Examples of resins that satisfy this condition include polyamide films and polyester films, and stretched films thereof are preferably used. Among them, it is particularly preferable to use biaxially stretched polyester films such as biaxially stretched polyamide films, biaxially stretched polybutylene terephthalate (PBT) films, biaxially stretched polyethylene terephthalate (PET) films, or biaxially stretched polyethylene naphthalate (PEN) films as the heat-resistant resin layer 13. The polyamide film is not particularly limited, and examples thereof include 6 polyamide films, 6,6 polyamide, and MXD polyamide films. The heat-resistant resin layer 13 may be formed as a single layer, or may be formed as a multi-layer structure made of, for example, a polyester film / polyamide film (such as a multi-layer structure made of a PET film / nylon film).

[0060] The thickness of the heat-resistant resin layer 13 is preferably 7 μm to 50 μm, which ensures sufficient strength as a packaging material in addition to chemical resistance such as protection from electrolytes, and improves formability by reducing stress during molding such as stretch molding and drawing. The thickness of the heat-resistant resin layer 13 is more preferably 9 μm to 30 μm.

[0061] In addition, a protective layer containing a binder resin and solid fine particles may be laminated on the outside of the heat-resistant resin layer 13. The protective layer is a layer that imparts slipperiness to the surface of the battery packaging material to improve formability, and also imparts excellent chemical resistance, solvent resistance, and abrasion resistance. (Barrier layer) The barrier layer 11 plays a role of imparting gas barrier properties that prevent the intrusion of oxygen and moisture to the battery packaging material 1. The barrier layer 11 is not particularly limited, and examples thereof include metal foils such as 1000-series, 3000-series, and 8000-series aluminum foils, SUS foils (stainless steel foils), copper foils, nickel foils, titanium foils, and clad foils. The thickness of the barrier layer 11 is preferably 20 μm to 100 μm. By having a thickness of 20 μm or more, it is possible to prevent the occurrence of pinholes during rolling in the production of the metal foil, and by having a thickness of 100 μm or less, it is possible to reduce stress during molding such as stretch molding and drawing, thereby improving moldability. The particularly preferred thickness of the barrier layer 11 is 25 μm to 85 μm.

[0062] In addition, it is preferable that an undercoat layer is formed on at least the surface of the barrier layer 11 on the heat-resistant resin layer 13 side. In the battery packaging material 2 of Fig. 2, undercoat layers 16a, 16b are formed on both sides of the barrier layer 11. The undercoat layer 16b on the heat-resistant resin layer 13 side has the effect of increasing the adhesion between the barrier layer 11 and the first adhesive layer 12 and increasing the adhesive strength, and can prevent the occurrence of delamination between the barrier layer 11 and the heat-resistant resin layer 13. The undercoat layer 16b on the sealant layer 15 side increases the adhesion between the barrier layer 11 and the second adhesive layer 14, preventing delamination between the barrier layer 11 and the sealant layer 15, and can prevent corrosion of the metal foil surface due to the contents (such as the electrolyte of the battery) in the battery element chamber 54 of the battery case 60 (see Fig. 3).

[0063] An example of the underlayers 16a and 16b is a chemical conversion film. The chemical conversion film can be formed by subjecting the barrier layer 11 to a chemical conversion treatment such as that described below.

[0064] The surface of the barrier layer 11 that has been subjected to the degreasing treatment is coated with an aqueous solution of any one of the following 1) to 3), and then dried, thereby carrying out a chemical conversion treatment. 1) An aqueous solution of a mixture containing phosphoric acid, chromic acid, and at least one compound selected from the group consisting of metal salts of fluorides and nonmetal salts of fluorides. 2) An aqueous solution of a mixture containing phosphoric acid, at least one resin selected from the group consisting of acrylic resins, chitosan derivative resins, and phenolic resins, and at least one compound selected from the group consisting of chromic acid and chromium (III) salts. 3) An aqueous solution of a mixture containing phosphoric acid, at least one resin selected from the group consisting of acrylic resins, chitosan derivative resins, and phenolic resins, at least one compound selected from the group consisting of chromic acid and chromium (III) salts, and at least one compound selected from the group consisting of metal salts of fluorides and nonmetal salts of fluorides. The underlayers 16a and 16b have a chromium deposition amount (per side) of 0.1 mg / m 2 ~50mg / m 2 is preferred, and 2 mg / m 2 ~20mg / m 2 is preferred. (Sealant layer) The sealant layer 15 provides excellent chemical resistance against highly corrosive electrolytes and the like, and also provides the battery packaging material 1 with heat sealability.

[0065] The resin constituting the sealant layer 15 is preferably a single-layer or multi-layer film of a polyolefin resin such as a propylene resin, and preferably a non-oriented film. Examples of the propylene resin include propylene polymer (homo PP), propylene-ethylene copolymer, and propylene-butylene copolymer, and other propylene-α-olefin copolymers. The propylene-α-olefin copolymer may be either a random copolymer or a block copolymer. As a multi-layer propylene film, a three-layer film of a propylene random copolymer-propylene block copolymer-propylene random copolymer is recommended. The multi-layer film can be produced by co-extrusion or the like.

[0066] The thickness of the sealant layer 15 is preferably 20 μm to 100 μm, and more preferably 30 μm to 80 μm. The thickness ratio of each layer of the above-mentioned propylene random copolymer-propylene block copolymer-propylene random copolymer three-layer co-extruded film is preferably 1-3:4-8:1-3, where the total thickness is 10.

[0067] Additives such as a lubricant and an antiblocking material may be contained in the sealant layer 15. The lubricant in the sealant layer 15 is not particularly limited, but examples thereof include saturated fatty acid amides, unsaturated fatty acid amides, substituted amides, methylol amides, saturated fatty acid bisamides, unsaturated fatty acid bisamides, fatty acid ester amides, and aromatic bisamides.

[0068] The saturated fatty acid amide is not particularly limited, but examples thereof include lauric acid amide, palmitic acid amide, stearic acid amide, behenic acid amide, hydroxystearic acid amide, etc. The unsaturated fatty acid amide is not particularly limited, but examples thereof include oleic acid amide, erucic acid amide, etc.

[0069] The substituted amide is not particularly limited, but examples thereof include N-oleyl palmitic acid amide, N-stearyl stearic acid amide, N-stearyl oleic acid amide, N-oleyl stearic acid amide, N-stearyl erucic acid amide, etc. The methylol amide is not particularly limited, but examples thereof include methylol stearic acid amide, etc.

[0070] The saturated fatty acid bisamide is not particularly limited, but examples thereof include methylene bisstearic acid amide, ethylene biscapric acid amide, ethylene bislauric acid amide, ethylene bisstearic acid amide, ethylene bishydroxystearic acid amide, ethylene bisbehenic acid amide, hexamethylene bisstearic acid amide, hexamethylene bisbehenic acid amide, hexamethylene hydroxystearic acid amide, N,N'-distearyl adipic acid amide, and N,N'-distearyl sebacic acid amide.

[0071] The unsaturated fatty acid bisamide is not particularly limited, but examples thereof include ethylene bisoleamide, ethylene biserucamide, hexamethylene bisoleamide, and N,N'-dioleylsebacamide.

[0072] The fatty acid ester amide is not particularly limited, but examples thereof include stearamide ethyl stearate. The aromatic bisamide is not particularly limited, but examples thereof include m-xylylene bisstearic acid amide, m-xylylene bishydroxystearic acid amide, and N,N'-cystearyl isophthalic acid amide. The lubricant concentration is preferably 300 ppm to 5000 ppm, and more preferably 500 ppm to 3000 ppm. In addition, the inner surface of the sealant layer is 0.1 μg / cm2 to 1.0 μg / cm2. 2 It is preferred that a lubricant of at least one of these is present.

[0073] The antiblocking material is not particularly limited, but examples thereof include silica particles, acrylic resin particles, and aluminum silicate particles. The particle size of the antiblocking material is preferably in the range of 0.1 μm to 10 μm in average particle size, and more preferably in the range of 1 μm to 5 μm in average particle size. The content concentration of the antiblocking material is preferably set to 100 ppm to 5000 ppm. (Second adhesive layer) The second adhesive layer 14 is not particularly limited, but for example, an adhesive containing one or more of polyurethane resin, acrylic resin, epoxy resin, polyolefin resin, elastomer resin, fluorine resin, and acid-modified polypropylene resin is recommended. Among them, an adhesive made of polyurethane composite resin containing acid-modified polyolefin as a main component is preferable. The preferred thickness of the second adhesive layer 14 is 2 μm to 5 μm in the dry lamination method, and 3 μm to 20 μm in the sand lamination method, thermal lamination method, and the like.

[0074] Also, the second adhesive layer 14 may be made of the same type of active energy curing adhesive composition as the first adhesive layer 12 . [Battery case and battery] The battery 60 in FIG. 3 includes a battery case 50 made from the battery packaging material 1 of the present invention.

[0075] The battery case 50 is made of a molded container 51 and a cover plate 52, and is produced by placing the sealant layers 15 of the two containers face to face and heat sealing the edges to form a battery element chamber 54 with the sealant layer 15 as the inner surface.

[0076] The battery 60 is produced by housing a battery element 55 including a positive electrode, a negative electrode, a separator, and an electrolyte in the battery element chamber 54 of the battery case 50 .

[0077] Since the battery case 50 of the battery 60 is made of the battery packaging material 1, delamination does not occur between the barrier layer 11 and the heat-resistant resin layer 13 even when the battery case 50 is heat-sealed or when the battery 60 is used in a high-temperature environment. EXAMPLES

[0078] [Production of battery packaging material] Battery packaging materials 1 and 2 having the structures shown in FIGS. 1 and 2 were produced by changing the material of the first adhesive layer 12. (Materials for the adhesive composition) As polyester polyurethane acrylate (A1) having a glass transition temperature (Tg) of 40° C. or lower, the following three types of compounds α1, α2, and α3 were synthesized. (α1) In a flask equipped with a nitrogen inlet tube, a stirrer, a distillation column, and a condenser, neopentyl glycol (190 g), 1,6-hexanediol (200 g), ethylene glycol (50 g), isophthalic acid (420 g), adipic acid (20 g), and sebacic acid (100 g) were added, and dehydration condensation was performed at an internal temperature of 180 to 200 ° C. while stirring. After confirming that the resin acid value became 15 mg KOH / g, the dehydration reaction was further carried out at 200 to 240 ° C. while performing nitrogen bubbling. After that, it was confirmed that the resin acid value became 2 mg KOH / g or less, and the internal pressure was reduced to 15 Torr to continue the reaction. It was confirmed that the resin acid value became 0.1 mg KOH / g or less, and a polyester polyol with a number average molecular weight of 4100 and a hydroxyl value of 27.4 mg KOH / g was obtained.

[0079] The obtained polyester polyol was cooled to 20° C., and dibutyltin dilaurate (0.2 g) and tolylene diisocyanate (55.4 g) were added and reacted at 80 to 85° C. for 6 hours under a nitrogen stream to obtain a urethane prepolymer having isocyanate groups at both ends. 2-Hydroxyethyl acrylate (30.8 g) was added to the obtained urethane prepolymer, and the reaction was allowed to proceed at 80 to 85°C. The reaction was allowed to proceed, and the synthesis was terminated when it was confirmed by infrared absorption spectroscopy that the absorption of the isocyanate group had completely disappeared. A polyester polyurethane acrylate with a number average molecular weight of 15,000 and a glass transition temperature (Tg) of -10°C was obtained. (α2) In a flask equipped with a nitrogen inlet tube, a stirrer, a distillation column, and a condenser, neopentyl glycol (120 g), 1,6-hexanediol (234 g), ethylene glycol (47 g), isophthalic acid (400 g), adipic acid (179 g), and sebacic acid (20 g) were added, and dehydration condensation was performed at an internal temperature of 180 to 200 ° C. while stirring. After confirming that the resin acid value became 15 mg KOH / g, the dehydration reaction was further carried out at 200 to 240 ° C. while performing nitrogen bubbling. After that, it was confirmed that the resin acid value became 2 mg KOH / g or less, and the internal pressure was reduced to 15 Torr to continue the reaction. It was confirmed that the resin acid value became 0.1 mg KOH / g or less, and a polyester polyol with a number average molecular weight of 4400 and a hydroxyl value of 25.5 mg KOH / g was obtained.

[0080] The obtained polyester polyol was cooled to 20° C., and dibutyltin dilaurate (0.2 g) and tolylene diisocyanate (61.5 g) were added and reacted at 80 to 85° C. for 6 hours under a nitrogen stream to obtain a urethane prepolymer having isocyanate groups at both ends. 2-Hydroxyethyl acrylate (35.9 g) was added to the obtained urethane prepolymer, and the reaction was allowed to proceed at 80 to 85°C. The reaction was allowed to proceed, and the synthesis was terminated when it was confirmed by infrared absorption spectroscopy that the absorption of the isocyanate group had completely disappeared. A polyester polyurethane acrylate with a number average molecular weight of 8000 and a glass transition temperature (Tg) of -20°C was obtained. (α3) In a flask equipped with a nitrogen inlet tube, a stirrer, a distillation column, and a condenser, neopentyl glycol (160 g), 1,6-hexanediol (210 g), ethylene glycol (50 g), isophthalic acid (405 g), adipic acid (100 g), and sebacic acid (65 g) were added, and dehydration condensation was performed at an internal temperature of 180 to 200 ° C. while stirring. After confirming that the resin acid value became 15 mg KOH / g, the dehydration reaction was further carried out at 200 to 240 ° C. while performing nitrogen bubbling. After that, it was confirmed that the resin acid value became 2 mg KOH / g or less, and the internal pressure was reduced to 15 Torr to continue the reaction. It was confirmed that the resin acid value became 0.1 mg KOH / g or less, and a polyester polyol with a number average molecular weight of 4350 and a hydroxyl value of 26.3 mg KOH / g was obtained.

[0081] The obtained polyester polyol was cooled to 20° C., and dibutyltin dilaurate (0.2 g) and tolylene diisocyanate (56.1 g) were added and reacted at 80 to 85° C. for 6 hours under a nitrogen stream to obtain a urethane prepolymer having isocyanate groups at both ends. 2-Hydroxyethyl acrylate (32.5 g) was added to the obtained urethane prepolymer, and the reaction was allowed to proceed at 80 to 85°C. The reaction was allowed to proceed, and the synthesis was terminated when it was confirmed by infrared absorption spectroscopy that the absorption of the isocyanate group had completely disappeared. A polyester polyurethane acrylate with a number average molecular weight of 11,000 and a glass transition temperature (Tg) of -13°C was obtained.

[0082] As polyester polyurethane acrylate (A2) having a glass transition temperature of more than 40° C., the following four types of compounds α11, α12, α13, and α14 were synthesized. (α11) In a flask equipped with a nitrogen inlet tube, a stirrer, a distillation column, and a condenser, neopentyl glycol (130 g), 1,6-hexanediol (180 g), ethylene glycol (80 g), isophthalic acid (310 g), and terephthalic acid (300 g) were added, and dehydration condensation was performed at an internal temperature of 180 to 200 ° C. while stirring. After confirming that the resin acid value became 15 mg KOH / g, the dehydration reaction was further carried out at 200 to 240 ° C. while performing nitrogen bubbling. After confirming that the resin acid value became 2 mg KOH / g or less, the internal pressure was reduced to 15 Torr and the reaction was continued. It was confirmed that the resin acid value became 0.1 mg KOH / g or less, and a polyester polyol with a number average molecular weight of 5800 and a hydroxyl value of 19.3 mg KOH / g was obtained.

[0083] The obtained polyester polyol was cooled to 20° C., and dibutyltin dilaurate (0.2 g) and tolylene diisocyanate (38.5 g) were added and reacted at 80 to 85° C. for 6 hours under a nitrogen stream to obtain a urethane prepolymer having isocyanate groups at both ends. 2-Hydroxyethyl acrylate (20.0 g) was added to the obtained urethane prepolymer, and the reaction was allowed to proceed at 80 to 85°C. The reaction was allowed to proceed, and the synthesis was terminated when it was confirmed by infrared absorption spectroscopy that the absorption of the isocyanate group had completely disappeared. A polyester polyurethane acrylate with a number average molecular weight of 6000 and a glass transition temperature (Tg) of 50°C was obtained. (α12) In a flask equipped with a nitrogen inlet tube, a stirrer, a distillation column, and a condenser, neopentyl glycol (130 g), 1,6-hexanediol (177 g), ethylene glycol (82 g), isophthalic acid (310 g), and terephthalic acid (301 g) were added, and dehydration condensation was performed at an internal temperature of 180 to 200 ° C. while stirring. After confirming that the resin acid value became 15 mg KOH / g, the dehydration reaction was further carried out at 200 to 240 ° C. while performing nitrogen bubbling. After confirming that the resin acid value became 2 mg KOH / g or less, the internal pressure was reduced to 15 Torr and the reaction was continued. It was confirmed that the resin acid value became 0.1 mg KOH / g or less, and a polyester polyol with a number average molecular weight of 5820 and a hydroxyl value of 19.2 mg KOH / g was obtained.

[0084] The obtained polyester polyol was cooled to 20° C., and dibutyltin dilaurate (0.2 g) and tolylene diisocyanate (38.4 g) were added and reacted at 80 to 85° C. for 6 hours under a nitrogen stream to obtain a urethane prepolymer having isocyanate groups at both ends. 2-Hydroxyethyl acrylate (19.3 g) was added to the obtained urethane prepolymer, and the reaction was allowed to proceed at 80 to 85°C. The reaction was allowed to proceed, and the synthesis was terminated when it was confirmed by infrared absorption spectroscopy that the absorption of the isocyanate group had completely disappeared. A polyester polyurethane acrylate with a number average molecular weight of 6230 and a glass transition temperature (Tg) of 51°C was obtained. (α13) In a flask equipped with a nitrogen inlet tube, a stirrer, a distillation column, and a condenser, neopentyl glycol (130 g), 1,6-hexanediol (173 g), ethylene glycol (85 g), isophthalic acid (310 g), and terephthalic acid (302 g) were added, and dehydration condensation was performed at an internal temperature of 180 to 200 ° C. while stirring. After confirming that the resin acid value became 15 mg KOH / g, the dehydration reaction was further carried out at 200 to 240 ° C. while performing nitrogen bubbling. After confirming that the resin acid value became 2 mg KOH / g or less, the internal pressure was reduced to 15 Torr and the reaction was continued. It was confirmed that the resin acid value became 0.1 mg KOH / g or less, and a polyester polyol with a number average molecular weight of 5850 and a hydroxyl value of 19.1 mg KOH / g was obtained.

[0085] The obtained polyester polyol was cooled to 20° C., and dibutyltin dilaurate (0.2 g) and tolylene diisocyanate (38.2 g) were added and reacted at 80 to 85° C. for 6 hours under a nitrogen stream to obtain a urethane prepolymer having isocyanate groups at both ends. 2-Hydroxyethyl acrylate (18.7 g) was added to the obtained urethane prepolymer, and the reaction was allowed to proceed at 80 to 85°C. The reaction was allowed to proceed, and the synthesis was terminated when it was confirmed by infrared absorption spectroscopy that the absorption of the isocyanate group had completely disappeared. A polyester polyurethane acrylate with a number average molecular weight of 6460 and a glass transition temperature (Tg) of 52°C was obtained. (α14) In a flask equipped with a nitrogen inlet tube, a stirrer, a distillation column, and a condenser, neopentyl glycol (130 g), 1,6-hexanediol (168 g), ethylene glycol (89 g), isophthalic acid (310 g), and terephthalic acid (303 g) were added, and dehydration condensation was performed at an internal temperature of 180 to 200 ° C. while stirring. After confirming that the resin acid value became 15 mg KOH / g, the dehydration reaction was further carried out at 200 to 240 ° C. while performing nitrogen bubbling. After that, it was confirmed that the resin acid value became 2 mg KOH / g or less, and the internal pressure was reduced to 15 Torr to continue the reaction. It was confirmed that the resin acid value became 0.1 mg KOH / g or less, and a polyester polyol with a number average molecular weight of 5890 and a hydroxyl value of 19.0 mg KOH / g was obtained.

[0086] The obtained polyester polyol was cooled to 20° C., and dibutyltin dilaurate (0.2 g) and tolylene diisocyanate (37.9 g) were added and reacted at 80 to 85° C. for 6 hours under a nitrogen stream to obtain a urethane prepolymer having isocyanate groups at both ends. 2-Hydroxyethyl acrylate (17.4 g) was added to the obtained urethane prepolymer, and the reaction was allowed to proceed at 80 to 85°C. The reaction was allowed to proceed, and the synthesis was terminated when it was confirmed by infrared absorption spectroscopy that the absorption of the isocyanate group had completely disappeared. A polyester polyurethane acrylate with a number average molecular weight of 6920 and a glass transition temperature (Tg) of 54°C was obtained.

[0087] As the (meth)acrylate monomer (B) having an isobornyl group, isobornyl acrylate (Light Acrylate IB-XA manufactured by Kyoeisha Chemical Co., Ltd., glass transition temperature of homopolymer is 94° C.) was used.

[0088] As the isocyanate compound (X) which is not a component of the polyester polyurethane acrylates (A1) and (A2), Takenate D170N manufactured by Takeda Pharmaceutical Co., Ltd. was used.

[0089] As the epoxy resin (C), jER1032H60 manufactured by Mitsubishi Chemical Corporation was used.

[0090] As the alkoxysilyl group-containing radically polymerizable compound (D), X-40-9296 manufactured by Shin-Etsu Chemical Co., Ltd. was used.

[0091] As the phosphate group-containing (meth)acrylate (E), Light Ester P-2M (2-methacryloyloxyethyl acid phosphate) manufactured by Kyoeisha Chemical Co., Ltd. was used.

[0092] As the photocationic polymerization initiator (F), Omnicat 250 manufactured by GM Resins BV was used.

[0093] The above-mentioned materials were mixed to prepare adhesive compositions of Examples 1 to 17 and Comparative Examples 1 to 4. Table 1 shows the types of (A1) and (A2) used in each example and the proportions of each component. (Examples 1 and 18) An adhesive composition was prepared by mixing α1 polyester polyurethane acrylate (A1), isobornyl acrylate (B), isocyanate compound (X), and auxiliary agents (C, D, E, F). In this example, polyester polyurethane acrylate (A2) was not used. (Examples 2 to 4, 6 to 16, Comparative Examples 1 and 2) An adhesive composition was prepared by blending polyester polyurethane acrylate (A1) of α1 or α2, polyester polyurethane acrylate (A2) of any one of α11 to α14, isobornyl acrylate (B), and auxiliary agents (C, D, E, F). In this example, no isocyanate compound (X) was used. Example 5 An adhesive composition was prepared by blending α1 polyester polyurethane acrylate (A1), isobornyl acrylate (B), and auxiliary agents (C, D, E, F). In this example, polyester polyurethane acrylate (A2) and isocyanate compound (X) were not used. (Example 17) An adhesive composition was prepared from α1 polyester polyurethane acrylate (A1) and isobornyl acrylate (B). In this example, polyester polyurethane acrylate (A2), isocyanate compound (X) and auxiliary agents (C, D, E, F) were not used. Comparative Example 3 An adhesive composition was prepared by blending polyester polyurethane acrylate α3 (A1), polyester polyurethane acrylate α12 (A2), ethylene glycol diacrylate as an acrylate monomer replacing isobornyl acrylate (B), and auxiliary agents (C, D, E, F). In this example, no isocyanate compound (X) was used. The blending amount of ethylene glycol diacrylate is shown in the column for isobornyl acrylate (B), and the mass ratio of (A1) to ethylene glycol diacrylate is shown in the column for A1 / B. [Production of battery packaging material] Battery packaging materials 1 and 2 having the laminated structure shown in FIG. 1 and FIG. 2 were produced using the adhesive composition of each of the above-mentioned examples as the first adhesive layer 12.

[0094] The materials other than the first adhesive layer 12 are common and are as follows.

[0095] As the barrier layer 11, an aluminum foil made of A8079 and having a thickness of 40 μm was used.

[0096] As the heat-resistant resin layer 13, a biaxially oriented nylon 6 film having a thickness of 15 μm was used.

[0097] As the sealant layer 15, a 30 μm thick unstretched polypropylene film containing 3000 ppm of erucamide was used.

[0098] The second adhesive layer 14 was made of the same adhesive composition as the first adhesive layer 12 . (Examples 1 to 15, 17, Comparative Examples 1 to 4) A chemical conversion coating was formed by applying a chemical conversion solution consisting of polyacrylic acid (acrylic resin), a chromium (III) salt compound, water, and alcohol to both sides of the barrier layer 11 and then drying at 150° C. The chromium deposition amount of this chemical conversion coating was 5 mg / m per side. 2 These chemical conversion coatings were used as base layers 16a and 16b.

[0099] The adhesive composition of each of the above-mentioned examples was adjusted in viscosity to a solid content of 25 mass % using ethyl acetate, and applied with a bar coater in a dry coating amount of 4.5 g / m to one side of the barrier layer 11 having the undercoat layers 16a and 16b formed on both sides. 2 The barrier layer 11 was coated so that the thickness would be 4 μm (after curing), and the ethyl acetate was evaporated using a dryer to form a first adhesive layer 12, after which a heat-resistant resin layer 13 was laminated. Furthermore, a second adhesive layer 14 having a thickness of 2 μm was formed on the other surface of the barrier layer 11 in the same manner as in the formation of the first adhesive layer 12, and a sealant layer 15 was laminated. Next, this laminate was nipped on a hot plate at 60° C. Thereafter, a UV irradiator was used to irradiate the layer with 300 mJ / cm. 2 The battery packaging material 2 shown in FIG. 2 was obtained by irradiating both sides with ultraviolet light for 3×3 seconds. Example 16 The layers were bonded together in the same manner as in Example 1, except that the underlayers 16a and 16b were not formed on the barrier layer 11, to produce a battery packaging material 1 having a laminated structure as shown in FIG. [Evaluation of battery packaging materials] The produced battery packaging materials 1 and 2 were tested and evaluated for sealing resistance, hot water resistance, moist heat resistance, and high-temperature lamination strength by the following methods. The results are shown in Table 1. (Seal resistance) A battery case 50 shown in Fig. 3 was produced using battery packaging materials 1 and 2, and a heat seal test was conducted. The battery case 60 comprises a formed container 51 and a flat cover plate 52. Note that while the battery case 60 in Fig. 3 uses battery packaging material 1, the battery case using battery packaging material 2 has the same shape, and therefore Fig. 3 will be used instead for the battery case using battery packaging material 2.

[0100] The formed container 51 was prepared by deep drawing the sheet-like battery packaging materials 1 and 2 into an approximately rectangular parallelepiped shape (approximately rectangular parallelepiped shape with one side open) of 55 mm in length × 35 mm in width × 5 mm in depth using a deep drawing tool manufactured by Amada Co., Ltd., and then trimming the portion extending outward from the edge of the opening of the rectangular parallelepiped, leaving a flange 53 with a width of 20 mm. The outer surface of the formed container 51 was a heat-resistant resin layer 13, and the inner surface was a sealant layer 15. The cover plate 52 was prepared by cutting the battery packaging material 1 into a rectangle of the same dimensions as the outer dimensions of the flange 53 of the formed container 51. Five sets of the formed container 51 and cover plate 52 were prepared.

[0101] The battery case was assembled by overlapping the sealant layer 15 side of the cover plate 52 on the molding container 51, and the overlapped flange 53 portion was sandwiched between a heater and heated at 70° C. for 6 seconds to be heat-sealed. In this manner, five heat-sealed battery cases 50 were obtained.

[0102] The five battery cases 50 after the heat sealing were visually observed to check for the occurrence of delamination in the heat sealed portion and for the occurrence of lifting in appearance, and were evaluated according to the following criteria. ◎: No delamination was observed, and no floating in appearance was observed (passed) ◯: Slight delamination may occur occasionally, but there is essentially no delamination and no visible lifting (passed) ×: Delamination occurred and the appearance was also lifted (failed) (Hot water resistance) Five battery cases 50 produced in the above-mentioned seal resistance test were immersed in hot water at 85°C for 240 hours, then removed and visually inspected for the occurrence of delamination in the heat-sealed areas and for the presence or absence of lifting in appearance, and evaluated based on the following criteria. ◎: No delamination was observed, and no floating in appearance was observed (passed) ◯: Slight delamination may occur occasionally, but there is essentially no delamination and no visible lifting (passed) ×: Delamination occurred and the appearance was also lifted (failed) (Moisture and heat resistance) The sheet-like battery packaging materials 1 and 2 were deep-drawn into an approximately rectangular parallelepiped shape (approximately rectangular parallelepiped shape with one side open) of 55 mm in length × 35 mm in width × 7 mm in depth using a deep-drawing tool manufactured by Amada Co., Ltd., to produce a formed container 51. These formed containers 51 were stored in a thermo-hygrostat at a temperature of 85°C × 85% RH × 7 days.

[0103] After 24 hours and 120 hours of storage, the molded container 51 was checked and evaluated based on the following criteria. ◎: No delamination after 120 seconds 〇: No delamination occurred after 24 hours, but delamination occurred after 120 hours ×: Delamination occurred after 24 hours (High temperature lamination strength) A test piece measuring 15 mm wide and 150 mm long was cut out from the battery packaging materials 1 and 2, and peeling was performed between the barrier layer 11 and the heat-resistant resin layer 13 in a region extending 10 mm inward from one end of the test piece in the longitudinal direction.

[0104] Based on JIS K6854-3 (1999), Shimadzu Strograph (AGS Using a chuck (-5kNX), the laminate including the barrier 11 was clamped and fixed with one chuck, and the peeled heat-resistant resin layer 13 was clamped and fixed with the other chuck, and after holding for 1 minute in a temperature environment of 120°C, T-peel was performed at a tensile speed of 100 mm / min in the same 120°C environment, and the peel strength was measured, and the value at which this measured value stabilized was taken as the "laminate strength at high temperature (N / 15 mm)". The measurement results were evaluated based on the following criteria. (Judgment criteria) ◎: 2.0N / 15mm or more ○: 1.5N / 15mm or more, less than 2.0N / 15mm ×: Less than 1.5N / 15mm

[0105] [Table 1]

[0106] From the results in Table 1, it was possible to confirm that by using the adhesive compositions of the Examples, high high-temperature strength could be obtained and delamination could be prevented. [Industrial Applicability]

[0107] The battery packaging material of the present invention can be suitably used as a case material for secondary batteries for vehicle-mounted, stationary, notebook computers, mobile phones, and cameras, in particular small, portable lithium-ion secondary batteries. [Explanation of symbols]

[0108] 1...Battery packaging material 11...Barrier layer 12...First adhesive layer 13...Heat-resistant resin layer 14...Second adhesive layer 15…Sealant layer 16a, 16b...base layer 50…Battery case 60...battery

Claims

1. A battery packaging material in which a heat-resistant resin layer is bonded to one surface of a barrier layer via a first adhesive layer, and a sealant layer is bonded to the other surface via a second adhesive layer, wherein the first adhesive layer is composed of an adhesive composition containing a polyester polyurethane acrylate (A) and a (meth)acrylate monomer (B) having an isobornyl group in a mass ratio of (A) / (B)=1 / 1 to 8 / 1, and the adhesive composition contains 0.1% by mass to 5% by mass of an alkoxysilyl group-containing radically polymerizable compound (D). The battery packaging material is characterized by this.

2. The battery packaging material according to Claim 1, wherein the adhesive composition further contains at least one of an epoxy resin (C), a phosphate group-containing (meth)acrylate (E), and a photo cationic polymerization initiator (F).

3. The battery packaging material according to Claim 1, wherein the adhesive composition further contains at least one of 1% by mass to 10% by mass of an epoxy resin (C), 0.1% by mass to 5% by mass of an alkoxysilyl group-containing radically polymerizable compound (D), 0.1% by mass to 5% by mass of a phosphate group-containing (meth)acrylate (E), and 0.1% by mass to 5% by mass of a photo cationic polymerization initiator (F).

4. The battery packaging material according to Claim 1 or 2, wherein a base layer is formed on at least the surface of the barrier layer on the heat-resistant resin layer side.

5. A battery case, characterized in that the battery packaging material according to Claim 1 or 2 is joined with the sealant layers facing each other inward, and a battery element chamber for housing a battery element is formed by heat-sealing the edges.

6. A secondary battery, characterized in that a battery element is housed in the battery element chamber of the battery case according to Claim 5.

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