Battery Packaging Materials

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 preferably used as a case for secondary batteries for in-vehicle, stationary, notebook computer, mobile phone, and camera applications, particularly small-sized portable lithium-ion secondary batteries.

Background Art

[0002] Power storage devices represented by lithium-ion secondary batteries can be processed into various shapes by using a laminate-type packaging material in which resin layers are laminated on both sides of a metal foil such as aluminum from cans or cases, and can be further made thinner and lighter.

[0003] A laminate-type battery packaging material is known in which a resin film for a heat-resistant resin layer that becomes the outer surface of the case is bonded to one surface of the metal foil with an adhesive, and a resin film for a sealant layer is bonded to the other surface with an adhesive, and various adhesives are used.

[0004] In conventional battery packaging materials, it was common to use a two-component curable urethane-based adhesive for bonding the metal foil and the resin film for the heat-resistant resin layer. However, since a heat aging process of 7 to 9 days is required for curing, there are problems such as poor productivity and high equipment costs due to the need for a large aging room. For this reason, instead of the two-component curable urethane-based adhesive, a battery packaging material that eliminates the heat aging process, significantly shortens the curing time, and does not require large equipment has been proposed by using an electron beam curable adhesive (see Patent Document 1).

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] The battery packaging material described in Patent Document 1 improves productivity because the adhesive hardens quickly by electron beam irradiation. However, when deep molding is performed during the manufacturing of the battery case, the aforementioned battery packaging material is prone to delamination (peeling) between the metal foil and the heat-resistant resin layer that forms the outer surface of the case. Furthermore, delamination is also prone to occur between the metal foil and the heat-resistant resin layer when heat sealing is performed to seal 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 technology, the present invention aims to improve the adhesive strength at high temperatures in battery packaging materials using electron beam curing adhesives that cure in a short time.

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

[0009] [1] A battery packaging material in which a heat-resistant resin layer is bonded to one side of a barrier layer via a first adhesive layer, and a sealant layer is bonded to the other side via a second adhesive layer. A battery packaging material characterized in that the first adhesive layer is composed of an adhesive composition containing polyester polyurethane acrylate (A) and (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 paragraph 1, wherein the adhesive composition comprises 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 less.

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

[0012] [4] The adhesive composition further comprises at least one of the following: 1% to 10% by mass of epoxy resin (C), 0.1% to 5% by mass of an alkoxysilyl group-containing radical polymerizable compound (D), 0.1% to 5% by mass of a phosphate group-containing (meth)acrylate (E), and 0.1% to 5% by mass of a photocationic polymerization initiator (F), as described in paragraph 1 or 2 above.

[0013] [5] The battery packaging material according to any one of paragraphs 1 to 4 above, wherein an underlayer is formed on at least the heat-resistant resin layer side of the barrier layer.

[0014] [6] A battery case characterized in that a battery element chamber for housing a battery element is formed by joining the battery packaging material described in any of paragraphs 1 to 5 above with the sealant layers facing inward and heat-sealing the edges.

[0015] [7] A secondary battery characterized in that a battery element is housed in a battery element chamber of the battery case described in paragraph 6 above. [Effects of the Invention]

[0016] The battery packaging material described in [1] above has a first adhesive layer that bonds the barrier layer and the heat-resistant resin layer, and is composed of an adhesive composition in which polyester polyurethane acrylate (A) and (meth)acrylate monomer (B) having an isobornyl group are blended in a predetermined ratio. Therefore, it can be cured in a short time by irradiation with active energy rays and has excellent adhesion and heat resistance. Accordingly, delamination between the barrier layer and the heat-resistant resin layer is prevented when heat sealing is performed to seal the battery case and 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 polyester polyurethane acrylates (A) with different glass transition temperatures, and the glass transition temperature of at least one polyester polyurethane acrylate is 40 °C or lower. Therefore, it is possible to achieve both the adhesiveness and heat resistance of the first adhesive layer.

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

[0019] According to the battery packaging material described in [5] above, the adhesion between the barrier layer and the heat-resistant resin layer is enhanced by the base layer, and the delamination prevention effect is improved.

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

[0021] Since the battery described in [7] above uses the battery case described in [6] above, 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. [Figure 2] FIG. 2 is a cross-sectional view showing another example of the battery packaging material of the present invention. [Figure 3] FIG. 3 is a cross-sectional view of a battery case made of the battery packaging material of FIG. 1.

Embodiments for Carrying Out the Invention

[0023] FIG. 1 shows an 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 the 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 Figure 3, the battery case 50 is manufactured by heat-sealing the edges of a molded container 51 and a lid plate 52 made of the battery packaging material 1, with their respective sealant layers 15 facing each other. The battery 60 is a battery with battery elements 55 sealed in a battery element chamber 54 of the battery case 50. In the manufactured battery case 50, the heat-resistant resin layer 13 becomes the outer layer, and the sealant layer 15 becomes the inner layer. In the present invention, when describing the position of each layer constituting the battery packaging material 1 in terms of direction, the direction of the heat-resistant resin layer 13 is referred to as the outer side, and the direction of the sealant layer 15 is referred to as the inner side.

[0026] This invention defines an adhesive composition that constitutes a first adhesive layer 12 between a barrier layer 11 and a heat-resistant resin layer 13 of a battery packaging material 1. [Main components of the first adhesive layer] The necessary conditions for the adhesive composition constituting the first adhesive layer 1 are that it contains polyester polyurethane acrylate (A) and (meth)acrylate monomer (B) having an isobornyl group in a mass ratio of (A) / (B) = 1 / 1 to 8 / 1. The adhesive composition hardens when irradiated with active energy and strongly adheres to the barrier layer 11 and the heat-resistant resin layer 13.

[0027] The polyester polyurethane acrylate (A) has a number of acryloyl functional groups in its molecule that is not particularly limited, but from the viewpoint of adhesion between substrates, it is preferably two or more, and more preferably two to four. If there are fewer than two acryloyl groups, the crosslinking density after curing is low, resulting in weak adhesion and heat resistance, and reduced practicality. If the number of (meth)acryloyl functional groups exceeds four, the crosslinking density is high, resulting in weak adhesion. The number average molecular weight is not particularly limited, but is preferably in the range of 4000 to 30000. If the number average molecular weight is less than 4000, the molecular weight between crosslinking points is low, resulting in impaired flexibility and weak adhesion. If the number average molecular weight exceeds 30000, the viscosity is high, and the coating suitability is reduced, making it impractical. Also, because the molecular weight between crosslinking points is high, it becomes too soft after curing, resulting in weak adhesion. The number average molecular weight in this invention was 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 curing adhesive composition by reducing the degree of freedom of atomic vibration and inhibiting molecular motion due to its ring structure, thereby improving the heat resistance of the first adhesive layer 12 and preventing 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 in a mass ratio of (A) / (B) = 1 / 1 to 8 / 1 to produce an adhesive composition with 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 adhesion weakens. 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 weakens. The preferred (A) / (B) ratio is 1 / 1 to 6 / 1.

[0030] The polyester polyurethane acrylate (A) does not need to be of a single type, but can be mixed with two or more different types. When using two or more types, it is preferable that at least one type is polyester polyurethane acrylate (A) with a glass transition temperature (Tg) of 40°C or lower. By using polyester polyurethane acrylate (A) with a low glass transition temperature (Tg), both adhesion and heat resistance can be achieved.

[0031] Furthermore, when using two or more types, all types may be polyester polyurethane acrylate (A) with a glass transition temperature (Tg) of 40°C or lower, or polyester polyurethane acrylate (A) with a glass transition temperature (Tg) of over 40°C may be used together with polyester polyurethane acrylate (A) with a glass transition temperature (Tg) of 40°C or lower.

[0032] In the following description, polyester polyurethane acrylate (A) with a glass transition temperature (Tg) of 40°C or less will be referred to as polyester polyurethane acrylate (A1), and polyester polyurethane acrylate (A) with a glass transition temperature (Tg) greater than 40°C will be referred to as polyester polyurethane acrylate (A2).

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

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

[0035] The polyester polyol (a-1) is, 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 and their acid anhydrides, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, tetrabromphthalic anhydride, tetrachlorophthalic anhydride, hetic anhydride, and hymicic anhydride, either alone or in mixtures, and for example, ethylene glycol, propylene glycol, diethylene glycol, dipropylene glycol, neopentyl glycol, triethylene glycol, tripropylene glycol, tetramethyl These polyhydric alcohol components, either individually or in mixtures, are obtained by dehydration condensation.

[0036] Other polyols besides polyester polyol (a-1) can also be used as the polyol component. Examples include low molecular weight polyols such as 1,6-hexanediol and trimethylolpropane, as well as polyether polyols, acrylic polyols, and polyurethane polyols, which can be used individually 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), and 2,2,4-trimethylhexa Examples include methylene diisocyanate and norbornene diisocyanate. Furthermore, polyfunctional polyisocyanate compounds include their biuret, nurate, and trimethylolpropane adduct forms. Examples of isocyanate compounds having a (meth)acryloyl group include 2-isocyanatoethyl (meth)acrylate, 2-(2-methacryloyloxyethyl oxy)ethyl isocyanate, and 1,1-(bisacryloyloxymethyl)ethyl isocyanate, which 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 Examples include (meth)acrylates, and compounds having two or more acryloyl groups include trimethylolpropanedi(meth)acrylate, trimethylolethanedi(meth)acrylate, pentaerythritoldi(meth)acrylate, pentaerythritoltri(meth)acrylate, dipentaerythritoldi(meth)acrylate, dipentaerythritoltri(meth)acrylate, dipentaerythritoltetra(meth)acrylate, dipentaerythritolpenta(meth)acrylate, and 2-hydroxy-3 acryloyloxypropyl(meth)acrylate, which can be used alone or in combination of two or more. Furthermore, considering the reaction rate during synthesis, compounds having a primary hydroxyl group are preferred, and among these, 2-hydroxyethyl(meth)acrylate is particularly preferred.

[0039] The synthesis of the polyester polyurethane acrylate (A) can be carried out in a solvent as needed. Examples of such solvents include hydrocarbons other than alcohols, acetate esters, and ketones, with ethyl acetate and methyl ethyl ketone being preferred from the viewpoint of coating workability. In addition, known reaction accelerators can be used in the synthesis of polyester polyurethane acrylate (A), and examples of reaction accelerators include metal catalysts such as dibutyltin diacetate, dibutyltin dilaurate, dioctyltin dilaurate, and dibutyltin dimalate, as well as 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 also contain polyisocyanate or an isocyanate compound (X) having radically polymerizable unsaturated bonds, which are not components of polyester polyurethane acrylate, as a component to enhance adhesion. By incorporating the isocyanate compound (X), the cohesive force is increased by the reaction between the isocyanate groups and the hydroxyl groups of the cured adhesive, or the moisture adhering to the barrier layer 11 and heat-resistant resin layer 13 to be bonded, resulting in excellent adhesion. However, if the isocyanate compound is incorporated in an amount exceeding 25% by mass, the curing time will be prolonged, or carbon dioxide gas may be generated when the isocyanate reacts with water such as humidity, causing bubbles to form in the adhesive layer. Therefore, it is preferable that the proportion of the isocyanate compound in the adhesive composition be 25% by mass or less. Note that the isocyanate compound (X) shown herein is not a component of polyester polyurethane acrylate (A).

[0041] The adhesive composition hardens when irradiated with active energy rays such as ultraviolet rays, X-rays, visible light, alpha rays, beta rays, gamma rays, and EB (electron beams) to form the first adhesive. layer A layer 12 is formed to bond 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, preventing delamination during heat sealing. [Auxiliary components in the first adhesive layer] In addition to the components mentioned above, the adhesive composition may optionally contain at least one of the auxiliary components listed below (C) to (F).

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

[0043] The aforementioned epoxy resin is a general term for resins having epoxy groups in their molecules and epoxy (meth)acrylates obtained by modifying resins having epoxy groups in their molecules and adding (meth)acryloyl groups to them. Specifically, examples include bisphenol A type epoxy resin, bisphenol F type epoxy resin, alicyclic epoxy resin, novolac type epoxy resin, and epoxy acrylate. 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 (Celoxide 2021P, Celoxide 2081, Epolid 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-Ornex Corporation (EBECRYL600, EBECRYL3603, EBECRYL3700). These can be used individually or in combination of two or more types.

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

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

[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 its molecule. Examples include vinyltrimethoxysilane, vinyltriethoxysilane, vinyltributoxysilane, allyltrimethoxysilane, 3-(meth)acryloxypropyltrimethoxysilane, 3-(meth)acryloxypropyltriethoxysilane, p-styryltrimethoxysilane, p-styryltrimethoxysilane, and organosiloxanes obtained by condensing these individually or in combination of two or more. These can be used individually or in combination of two or more.

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

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

[0049] The phosphate group-containing (meth)acrylate (E) can also be used alone or in combination with other phosphorus compounds that do not contain (meth)acryloyl groups, but the phosphate group-containing (meth)acrylate (E) that is involved in the crosslinking reaction is more preferable because it provides superior adhesion and durability. Examples of phosphate-containing (meth)acrylates (E) include 2-(meth)acryloyloxyethyl acid phosphate and bis(2-(meth)acryloyloxyethyl)-acid phosphate. Examples include those manufactured by Kyoeisha Chemical Co., Ltd. (Light Ester P-1M, Light Ester P-2M, Light Acrylate P-1A) and BASF (Laromer PA9083), which can be used alone or in combination of two or more.

[0050] The preferred content of phosphate group-containing (meth)acrylate (E) in the adhesive composition is 0.1% to 5% by mass. Exceeding 5% by mass may reduce adhesiveness and heat resistance.

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

[0052] The aforementioned photocationic polymerization initiator (F) is an onium salt such as an ionic aromatic sulfonium salt or aromatic iodonium salt, consisting of a cation and anion part. Examples include those manufactured by IGM Resins BV (Omnicat 250, Omnicat 270), ADEKA Corporation (ADEKA Optomer SP series), and Sunapro Co., Ltd. (CPI-100P, CPI-101A).

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

[0054] Furthermore, the adhesive composition may, as necessary, contain coloring pigments, extender pigments, dyes, tackifiers, dispersants, defoamers, wetting agents, antistatic agents, thickeners, antioxidants, UV absorbers, radical scavengers, etc., to the extent that it does not impair the performance.

[0055] The adhesive composition hardens instantaneously upon irradiation with active energy rays; however, a photoradical polymerization initiator may be added to improve the curability.

[0056] The aforementioned photoradical polymerization initiators include benzophenone, 2,2-dimethoxy-1,2-diphenylethane-1-one, 1-hydroxycyclohexylphenyl-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-methylpropionyl)-benzyl]-phenyl}-2-methylpropan-1-one, phenylglyoxylic acid methyl ester, and 2-methyl-1-[4-(methylthio)phenyl]-2-morpholinopropan- Examples include 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-diphenylphosphine oxide, 1,2-octanedione, ethanone, and 1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazole-3-yl]-,1-(O-acetyloxime), which can be used alone or in combination of two or more.

[0057] The adhesive composition can be diluted with solvents such as hydrocarbons, acetate esters, ketones, and alcohols to adjust its viscosity according to the coating method and 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 according to the coating method and the specifications of the coating machine, a reactive diluent having radical polymerization properties may be used within a range that does not impair the performance.

[0059] The reactive diluents 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, myristyl (meth)acrylate, and 1,3-butylene glycol diacrylate, 1,4-butanediol di(meth)acrylate. Examples include difunctional (meth)acrylates such as acrylate, ethyl 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, as well as polyfunctional (meth)acrylates such as trimethylolpropane tri(meth)acrylate, ethoxylated (3) trimethylolpropane tri(meth)acrylate, and propoxylated (3) glyceryl tri(meth)acrylate, which can be used alone or in combination of two or more. [Other layers] In the battery packaging material of the present invention, the layers other than the first adhesive layer 12 can be made of any known material as appropriate, and the bonding method is not particularly limited. The following describes suitable materials for the layers other than the first adhesive layer 12. (Heat-resistant resin layer) The heat-resistant resin layer 13 uses a heat-resistant resin film that does not melt at the heat-sealing temperature when heat-sealing the battery packaging material 1. The heat-resistant resin used has a melting point that is 10°C or more, preferably 20°C or more, 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 of these are preferably used. In particular, the heat-resistant resin layer 13 is preferably a biaxially oriented polyester film such as a biaxially oriented polyamide film, a biaxially oriented polybutylene terephthalate (PBT) film, a biaxially oriented polyethylene terephthalate (PET) film, or a biaxially oriented polyethylene naphthalate (PEN) film. The polyamide film is not particularly limited, but examples include 6-polyamide film, 6,6-polyamide, and MXD polyamide film. The heat-resistant resin layer 13 may be formed as a single layer, or it may be formed as a multilayer, for example, a polyester film / polyamide film (or a multilayer, such as a PET film / nylon film).

[0060] The thickness of the heat-resistant resin layer 13 is preferably 7 μm to 50 μm. This provides chemical resistance, such as protection from electrolytes, sufficient strength for use as a packaging material, and reduces stress during molding, such as stretch molding and deep drawing, thereby improving moldability. A more preferable thickness for the heat-resistant resin layer 13 is 9 μm to 30 μm.

[0061] Furthermore, 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 provides slipperiness to the surface of the battery packaging material to improve moldability, and also provides excellent chemical resistance, solvent resistance, and abrasion resistance. (Barrier layer) The barrier layer 11 plays a role in providing gas barrier properties to the battery packaging material 1, preventing the intrusion of oxygen and moisture. The barrier layer 11 is not particularly limited, but examples include metal foils such as 1000 series, 3000 series, and 8000 series aluminum foil, SUS foil (stainless steel foil), copper foil, nickel foil, titanium foil, and clad foil. The thickness of the barrier layer 11 is preferably 20 μm to 100 μm. A thickness of 20 μm or more prevents the occurrence of pinholes during rolling when manufacturing metal foil, while a thickness of 100 μm or less reduces stress during molding such as stretch molding and deep drawing, thereby improving moldability. A particularly preferred thickness of the barrier layer 11 is 25 μm to 85 μm.

[0062] Furthermore, it is preferable that the barrier layer 11 has a base layer formed on at least the side of the barrier layer 11 facing the heat-resistant resin layer 13. In the battery packaging material 2 shown in Figure 2, base layers 16a and 16b are formed on both sides of the barrier layer 11. The base 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, thereby increasing the adhesive strength and preventing delamination between the barrier layer 11 and the heat-resistant resin layer 13. The base 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 also protects the battery case 50 This prevents corrosion of the metal foil surface by the contents (battery electrolyte, etc.) inside the battery element chamber 54 (see Figure 3).

[0063] Examples of the aforementioned underlayers 16a and 16b include a chemical conversion coating. The chemical conversion coating can be formed by applying, for example, the following chemical conversion treatment to the barrier layer 11.

[0064] After degreasing the surface of the barrier layer 11, a chemical conversion treatment is performed by applying one of the aqueous solutions from 1) to 3) below and then drying it. 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 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 aforementioned underlayers 16a and 16b have a chromium deposition amount (per side) of 0.1 mg / m². 2 ~50mg / m 2 Preferably, 2 mg / m² 2 ~20mg / m 2 It is preferable. (Sealant layer) The sealant layer 15 provides excellent chemical resistance to highly corrosive electrolytes and other substances, and also plays a role in providing heat-sealability to the battery packaging material 1.

[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-based resin, and an unstretched film is preferred. Examples of the propylene-based resin include propylene polymer (homoPP), propylene-ethylene copolymer, 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-based film, a three-layer film of propylene random copolymer-propylene block copolymer-propylene random copolymer is recommended. The multi-layer film can be manufactured by co-extrusion or the like.

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

[0067] The sealant layer 15 may contain additives such as lubricants and antiblocking agents. The lubricants in the sealant layer 15 are not particularly limited, but examples include saturated fatty acid amides, unsaturated fatty acid amides, substituted amides, methylolamides, saturated fatty acid bisamides, unsaturated fatty acid bisamides, fatty acid ester amides, aromatic bisamides, and the like.

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

[0069] The substituted amide is not particularly limited, but examples include N-oleyl palmitamide, N-stearyl stearate amide, N-stearyl oleamide, N-oleyl stearate amide, and N-stearyl erucate amide. The methylolamide is not particularly limited, but examples include methylol stearate amide.

[0070] The saturated fatty acid bisamides mentioned above are not particularly limited, but examples include methylenebisstearate, ethylenebiscaprate, ethylenebislaurate, ethylenebisstearate, ethylenebishydroxystearate, ethylenebisbehenamide, hexamethylenebisstearate, hexamethylenebisbehenamide, hexamethylenehydroxystearate, N,N'-distearyladipamide, N,N'-distearylsebacinamide, and the like.

[0071] The aforementioned unsaturated fatty acid bisamides are not particularly limited, but examples include ethylenebisoleamide, ethylenebiserucamide, hexamethylenebisoleamide, and N,N'-dioleylsebacinamide.

[0072] The fatty acid ester amide is not particularly limited, but examples include stearamidoethyl stearate. The aromatic bisamide is not particularly limited, but examples include m-xylylenebisstearate, m-xylylenebishydroxystearate, and N,N'-cystearyl isophthalamide. The lubricant concentration is preferably 300 ppm to 5000 ppm, and more preferably 500 ppm to 3000 ppm. In addition, 0.1 μg / cm² to 1.0 μg / cm² is applied to the inner surface of the sealant layer. 2 The presence of a lubricant is preferable.

[0073] The antiblocking material is not particularly limited, but examples 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 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 the following is recommended: polyurethane resin, acrylic resin, epoxy resin, polyolefin resin, elastomer resin, fluororesin, and acid-modified polypropylene resin. Among these, an adhesive made of a polyurethane composite resin with acid-modified polyolefin as the main component is preferred. The preferred thickness of the second adhesive layer 14 is 2 μm to 5 μm in dry lamination methods, and 3 μm to 20 μm in sand lamination methods, thermal lamination methods, etc.

[0074] Furthermore, the same type of active energy curing adhesive composition as that used for the first adhesive layer 12 can also be used as the second adhesive layer 14. [Battery case and batteries] The battery 60 in Figure 3 is equipped with a battery case 50 made of the battery packaging material 1 of the present invention.

[0075] The battery case 50 consists of a molded container 51 and a lid plate 52, and is manufactured by facing the respective sealant layers 15 towards each other and heat-sealing the edges to form a battery element chamber 54 with the sealant layer 15 as the inner surface.

[0076] Furthermore, the battery 60 is manufactured by housing battery elements 55, which include 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, the barrier layer 11 and the heat-resistant resin layer 13 do not delaminate when the battery case 50 is heat-sealed or when the battery 60 is used in a high-temperature environment. [Examples]

[0078] [Manufacturing of battery packaging materials] Battery packaging materials 1 and 2, with the structures shown in Figures 1 and 2, were fabricated by changing the material of the first adhesive layer 12. (Materials for adhesive composition) Three compounds, α1, α2, and α3, were synthesized as polyester polyurethane acrylates (A1) with a glass transition temperature (Tg) of 40°C or lower. (α1) In a flask equipped with a nitrogen inlet tube, stirrer, rectification column, and condenser, neopentyl glycol (190g), 1,6-hexanediol (200g), ethylene glycol (50g), isophthalic acid (420g), adipic acid (20g), and sebacic acid (100g) were added. Dehydration condensation was carried out at an internal temperature of 180-200°C while stirring, and after confirming that the resin acid value reached 15 mgKOH / g, the dehydration reaction was further carried out at 200-240°C while nitrogen bubbling was performed. After confirming that the resin acid value was 2 mgKOH / g or less, the internal pressure was reduced to 15 Torr and the reaction continued, and after confirming that the resin acid value was 0.1 mgKOH / g or less, a polyester polyol with a number average molecular weight of 4100 and a hydroxyl value of 27.4 mgKOH / 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. The mixture was reacted under a nitrogen atmosphere at 80-85°C for 6 hours to obtain a urethane prepolymer having isocyanate groups at both ends. 30.8 g of 2-hydroxyethyl acrylate was added to the obtained urethane prepolymer, and the reaction was carried out at 80-85°C. After the reaction had progressed, the synthesis was terminated by confirming that the absorption of the isocyanate group had completely disappeared using infrared absorption spectroscopy. 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, stirrer, rectification column, and 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. Dehydration condensation was carried out at an internal temperature of 180-200°C while stirring, and after confirming that the resin acid value reached 15 mg KOH / g, the dehydration reaction was further carried out at 200-240°C while nitrogen bubbling was performed. After confirming that the resin acid value was 2 mg KOH / g or less, the internal pressure was reduced to 15 Torr and the reaction continued, and after confirming that the resin acid value was 0.1 mg KOH / g or less, 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. The mixture was reacted under a nitrogen atmosphere at 80-85°C for 6 hours to obtain a urethane prepolymer having isocyanate groups at both ends. 35.9 g of 2-hydroxyethyl acrylate was added to the obtained urethane prepolymer, and the reaction was carried out at 80-85°C. After the reaction had progressed, the synthesis was terminated by confirming that the absorption of the isocyanate group had completely disappeared using infrared absorption spectroscopy. 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, stirrer, rectification column, and 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. Dehydration condensation was carried out at an internal temperature of 180-200°C while stirring, and after confirming that the resin acid value reached 15 mg KOH / g, the dehydration reaction was further carried out at 200-240°C while nitrogen bubbling was performed. After confirming that the resin acid value was 2 mg KOH / g or less, the internal pressure was reduced to 15 Torr and the reaction continued, and after confirming that the resin acid value was 0.1 mg KOH / g or less, 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. The mixture was reacted under a nitrogen atmosphere at 80-85°C for 6 hours to obtain a urethane prepolymer having isocyanate groups at both ends. 32.5 g of 2-hydroxyethyl acrylate was added to the obtained urethane prepolymer, and the reaction was carried out at 80-85°C. After the reaction had progressed, the synthesis was terminated after confirming that the absorption of the isocyanate group had completely disappeared by infrared absorption spectroscopy. A polyester polyurethane acrylate with a number-average molecular weight of 11000 and a glass transition temperature (Tg) of -13°C was obtained.

[0082] Four compounds, α11, α12, α13, and α14, were synthesized as polyester polyurethane acrylates (A2) with a glass transition temperature exceeding 40°C. (α11) In a flask equipped with a nitrogen inlet tube, stirrer, rectification column, and 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. Dehydration condensation was carried out at an internal temperature of 180-200°C while stirring, and after confirming that the resin acid value reached 15 mg KOH / g, the dehydration reaction was further carried out at 200-240°C while nitrogen bubbling was performed. After confirming that the resin acid value was 2 mg KOH / g or less, the internal pressure was reduced to 15 Torr and the reaction continued, and after confirming that the resin acid value was 0.1 mg KOH / g or less, 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. The mixture was reacted under a nitrogen atmosphere at 80-85°C for 6 hours to obtain a urethane prepolymer having isocyanate groups at both ends. 20.0 g of 2-hydroxyethyl acrylate was added to the obtained urethane prepolymer, and the reaction was carried out at 80-85°C. After the reaction had progressed, the synthesis was terminated by confirming that the absorption of the isocyanate group had completely disappeared using infrared absorption spectroscopy. 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, stirrer, rectification column, and 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. Dehydration condensation was carried out at an internal temperature of 180-200°C while stirring, and after confirming that the resin acid value reached 15 mg KOH / g, the dehydration reaction was further carried out at 200-240°C while nitrogen bubbling was performed. After confirming that the resin acid value was 2 mg KOH / g or less, the internal pressure was reduced to 15 Torr and the reaction continued, and after confirming that the resin acid value was 0.1 mg KOH / g or less, 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. The mixture was reacted under a nitrogen atmosphere at 80-85°C for 6 hours to obtain a urethane prepolymer having isocyanate groups at both ends. 19.3 g of 2-hydroxyethyl acrylate was added to the obtained urethane prepolymer, and the reaction was carried out at 80-85°C. After the reaction had progressed, the synthesis was terminated after confirming that the absorption of the isocyanate group had completely disappeared by infrared absorption spectroscopy. 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, stirrer, rectification column, and 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. Dehydration condensation was carried out at an internal temperature of 180-200°C while stirring, and after confirming that the resin acid value reached 15 mg KOH / g, the dehydration reaction was further carried out at 200-240°C while nitrogen bubbling was performed. After confirming that the resin acid value was 2 mg KOH / g or less, the internal pressure was reduced to 15 Torr and the reaction continued, and after confirming that the resin acid value was 0.1 mg KOH / g or less, 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. The mixture was reacted under a nitrogen atmosphere at 80-85°C for 6 hours to obtain a urethane prepolymer having isocyanate groups at both ends. 18.7 g of 2-hydroxyethyl acrylate was added to the obtained urethane prepolymer, and the reaction was carried out at 80-85°C. After the reaction had progressed, the synthesis was terminated by confirming that the absorption of the isocyanate group had completely disappeared using infrared absorption spectroscopy. 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, stirrer, rectification column, and 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. Dehydration condensation was carried out at an internal temperature of 180-200°C while stirring, and after confirming that the resin acid value reached 15 mg KOH / g, the dehydration reaction was further carried out at 200-240°C while nitrogen bubbling was performed. After confirming that the resin acid value was 2 mg KOH / g or less, the internal pressure was reduced to 15 Torr and the reaction continued, and after confirming that the resin acid value was 0.1 mg KOH / g or less, 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. The mixture was reacted under a nitrogen atmosphere at 80-85°C for 6 hours to obtain a urethane prepolymer having isocyanate groups at both ends. 17.4 g of 2-hydroxyethyl acrylate was added to the obtained urethane prepolymer, and the reaction was carried out at 80-85°C. After the reaction had progressed, the synthesis was terminated by confirming that the absorption of the isocyanate group had completely disappeared using infrared absorption spectroscopy. 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., with a homopolymer glass transition temperature of 94°C) was used.

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

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

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

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

[0092] Omnicat 250 from GM Resins BV was used as the photocationic polymerization initiator (F).

[0093] Adhesive compositions for Examples 1-17 and Comparative Examples 1-4 were prepared by blending the materials described above. Table 1 shows the types of (A1) and (A2) used in each example, and the proportion of each component. (Examples 1 and 18) An adhesive composition was prepared by combining 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 2-4, 6-16, Comparative Examples 1, 2) Adhesive compositions were prepared by combining α1 or α2 polyester polyurethane acrylate (A1), any of α11 to α14 polyester polyurethane acrylate (A2), isobornyl acrylate (B), and auxiliary agents (C, D, E, F). In this example, an isocyanate compound (X) was not used. (Example 5) Adhesive compositions were prepared by combining α1 polyester polyurethane acrylate (A1), isobornyl acrylate (B), and auxiliary agents (C, D, E, F). In this example, polyester polyurethane acrylate (A2) and isocyanate compounds (X) were not used. (Example 17) An adhesive composition was prepared using 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) Adhesive compositions were prepared by blending α3 polyester polyurethane acrylate (A1), α12 polyester polyurethane acrylate (A2), ethylene glycol diacrylate as an acrylate monomer to replace isobornyl acrylate (B), and auxiliary agents (C, D, E, F). In this example, an isocyanate compound (X) was not used. The amount of ethylene glycol diacrylate blended is indicated in the column for isobornyl acrylate (B), and the mass ratio of (A1) to ethylene glycol diacrylate is indicated in the A1 / B column. [Manufacturing of battery packaging materials] Battery packaging materials 1 and 2, which have a laminated structure as shown in Figures 1 and 2, were prepared using the adhesive compositions of the above-described 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 with a thickness of 40 μm was used.

[0096] A biaxially oriented nylon 6 film with a thickness of 15 μm was used as the heat-resistant resin layer 13.

[0097] As the sealant layer 15, a 30 μm thick unoriented polypropylene film containing 3000 ppm of erucic acid amide was used.

[0098] The same adhesive composition as the first adhesive layer 12 was used for the second adhesive layer 14. (Examples 1-15, 17, Comparative Examples 1-4) A chemical conversion treatment solution consisting of polyacrylic acid (acrylic resin), chromium(III) salt compound, water, and alcohol was applied to both sides of the barrier layer 11, and then dried at 150°C to form a chemical conversion film. The amount of chromium deposited on this chemical conversion film was 5 mg / m² per side. 2 Therefore, this chemical conversion coating was used as the base layers 16a and 16b.

[0099] The adhesive compositions in each of the above examples were prepared by adjusting the viscosity of the adhesive composition using ethyl acetate to achieve a solid content of 25% by mass. The adhesive was then applied to one side of a barrier layer 11, which had underlayers 16a and 16b formed on both sides, using a bar coater at a dry application rate of 4.5 g / m². 2 The barrier layer 11 was coated to a thickness of 4 μm after curing, and the ethyl acetate was evaporated with a dryer to form the first adhesive layer 12, after which the heat-resistant resin layer 13 was bonded. Furthermore, a second adhesive layer 14 with a thickness of 2 μm was formed on the other side of the barrier layer 11 in the same manner as the formation of the first adhesive layer 12, and the sealant layer 15 was bonded. Next, this laminate was nipped on a hot plate at 60°C. After that, it was subjected to UV irradiation at 300 mJ / cm². 2 By irradiating both sides with ultraviolet light for 3 seconds, the battery packaging material 2 shown in Figure 2 was obtained. (Example 16) Except for not forming the underlayers 16a and 16b on the barrier layer 11, each layer was bonded together using the same method as in Example 1 to produce a battery packaging material 1 with the laminated structure shown in Figure 1. [Evaluation of battery packaging materials] The sealing resistance, hot water resistance, heat and humidity resistance, and high-temperature lamination strength of the prepared battery packaging materials 1 and 2 were tested and evaluated using the following methods. The results are shown in Table 1. (Seal resistance) A battery case 50, as shown in Figure 3, was fabricated using battery packaging materials 1 and 2, and a heat seal test was performed. 50 It consists of a molded container 51 and a flat lid plate 52. Note that the battery case in Figure 3 50 Although Figure 1 uses battery packaging material 1, the battery case using battery packaging material 2 has the same shape, so Figure 3 is used as a substitute for the battery case using battery packaging material 2.

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

[0101] The battery case was assembled by placing the sealant layer 15 side of the lid plate 52 on top of the molded container 51, and the overlapping flange 53 portion was sandwiched between heaters and heat-sealed by heating at 70°C for 6 seconds. This resulted in obtaining five heat-sealed battery cases 50.

[0102] The five battery cases 50 after heat sealing were visually inspected to check for delamination in the heat-sealed areas and for any lifting of the surface, and were evaluated based on the following criteria. ◎: No delamination was observed, and no lifting of the exterior was observed (Pass) ○: Slight delamination may occasionally occur, but in practice there is no delamination and no visible lifting of the surface (Pass) ×: Delamination was present, and there was also some lifting of the exterior (failed). (Hot water resistance) Five battery cases 50 prepared in the above-mentioned seal resistance test were immersed in 85°C hot water for 240 hours. After removal, they were visually inspected to check for delamination in the heat-sealed areas and for any lifting of the surface, and evaluated based on the following criteria. ◎: No delamination was observed, and no lifting of the exterior was observed (Pass) ○: Slight delamination may occasionally occur, but in practice there is no delamination and no visible lifting of the surface (Pass) ×: Delamination was present, and there was also some lifting of the exterior (failed). (Heat and moisture resistance) Sheet-shaped battery packaging materials 1 and 2 were deep-drawn using a deep-drawing tool manufactured by Amada Co., Ltd. to form a roughly rectangular parallelepiped shape (a roughly rectangular parallelepiped shape with one open side) measuring 55 mm in length, 35 mm in width, and 7 mm in depth, thereby producing molded containers 51. These molded containers 51 were stored in a constant temperature and humidity chamber at 85°C and 85% RH for 7 days.

[0103] The molded container 51 was checked at 24 hours and 120 hours after storage and evaluated based on the following criteria. ◎: No delamination after 120 hours ○: Delamination was not observed after 24 hours, but was observed after 120 hours. ×: Delamination occurred after 24 hours. (High-temperature lamination strength) A test specimen measuring 15 mm in width and 150 mm in length was cut from battery packaging materials 1 and 2, and the barrier layer 11 and the heat-resistant resin layer 13 were separated in a region extending 10 mm inward from one end of the length of the test specimen.

[0104] In accordance with JIS K6854-3 (1999), a Shimadzu Strograph (AGS-5kNX) was used, with one chuck forming a barrier. layer The laminate containing 11 was clamped and fixed, and the peeled heat-resistant resin layer 13 was clamped and fixed with the other chuck. After being held in a 120°C environment for 1 minute, the peel strength was measured when it was peeled in a T-shape at a tensile speed of 100 mm / min in the same 120°C environment, and the value at which this measurement stabilized was defined as the "high-temperature lamination strength (N / 15mm)". 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 ×: 1.5N / less than 15mm

[0105] [Table 1]

[0106] The results in Table 1 confirm that using the adhesive composition of the example can achieve high high-temperature strength and prevent delamination. [Industrial applicability]

[0107] The battery packaging material of the present invention can be suitably used as a case material for rechargeable batteries for vehicles, stationary devices, laptop computers, mobile phones, and cameras, and especially for small portable lithium-ion rechargeable 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. This battery packaging material has a heat-resistant resin layer bonded to one side of a barrier layer via a first adhesive layer, and a sealant layer bonded to the other side via a second adhesive layer. The first adhesive layer is composed of an adhesive composition containing polyester polyurethane acrylate (A) and (meth)acrylate monomer (B) having an isobornyl group in a mass ratio of (A) / (B) = 1 / 1 to 8 / 1. The adhesive composition comprises 0.1% to 5% by mass of an alkoxysilyl group-containing radical polymerizable compound (D), The aforementioned adhesive composition is further characterized by containing at least one of the following: epoxy resin (C), phosphate group-containing (meth)acrylate (E), and photocationic polymerization initiator (F).

2. A battery packaging material comprising a barrier layer to which a heat-resistant resin layer is bonded via a first adhesive layer, and a sealant layer to which a second adhesive layer is bonded to the other side of the barrier layer, The first adhesive layer is composed of an adhesive composition containing polyester polyurethane acrylate (A) and (meth)acrylate monomer (B) having an isobornyl group in a mass ratio of (A) / (B) = 1 / 1 to 8 / 1. The adhesive composition comprises 0.1% to 5% by mass of an alkoxysilyl group-containing radical polymerizable compound (D), The adhesive composition further comprises at least one of the following: 1% to 10% by mass of epoxy resin (C), 0.1% to 5% by mass of phosphate group-containing (meth)acrylate (E), and 0.1% to 5% by mass of a photocationic polymerization initiator (F).

3. The battery packaging material according to claim 1 or 2, wherein an underlayer is formed on at least the surface of the barrier layer facing the heat-resistant resin layer.

4. A battery case characterized in that the battery packaging material according to claim 1 or 2 is joined together with the sealant layers facing inward and the edges are heat-sealed to form a battery element chamber for housing battery elements.

5. A secondary battery characterized in that a battery element is housed in a battery element chamber of the battery case described in claim 4.

Images