Two-part adhesives, laminates, molded products, packaging materials

Abstract

To provide a packaging material which has excellent moldability and is free from deterioration of adhesive strength and poor appearance even after thermal fusion of the sealant layer.SOLUTION: A two-liquid type adhesive comprises: a polyol composition (A) and a polyisocyanate composition (B), where the polyol composition (A) comprises a polyester polyol (A1) which is a reaction product of a polyvalent carboxylic acid and a polyhydric alcohol and in which 30 mole% or more of the polyfunctional carboxylic acid is an aromatic polyfunctional carboxylic acid. The polyisocyanate composition (B) comprises: a urethane prepolymer (B1) which is a reaction product of a polyol (b1-1) including a polyether polyol and a polyisocyanate (b1-2); and a trimethylolpropane adduct (B2) of toluene diisocyanate, where a ratio of the trimethylolpropane adduct (B2) of toluene diisocyanate in the solid content of the polyisocyanate composition (B) is 10 mass% to 85 mass%.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a two-component adhesive, a laminate, a molded body, and a packaging material obtained by using the two-component adhesive.

Background Art

[0002] Packaging materials used for packaging various stored items such as foods, daily necessities, and electronic components need to protect the contents from impacts received during distribution and deterioration caused by oxygen and moisture. Therefore, functions such as strength, crack resistance, and gas barrier properties are required. When the contents are subjected to heat sterilization, retort resistance, heat resistance, etc. are necessary, and transparency may also be required so that the contents can be confirmed. However, it is difficult to satisfy the necessary functions with a single type of material. For example, an unstretched polyolefin film used for sealing by heat sealing is excellent in heat processing properties but insufficient in oxygen barrier properties. On the contrary, a nylon film is excellent in gas barrier properties but inferior in heat sealing properties.

[0003] For these reasons, laminates obtained by laminating different polymer materials or a polymer material and a metal substrate are widely used as packaging materials. In addition, a laminate formed by molding a laminate to form one or more storage portions may be used as a packaging material (Patent Documents 1-3). A laminate in which one or more storage portions are formed seals the storage portions by being joined to a laminate in which storage portions having the same shape are formed or a laminate in which no storage portion is formed (not molded). Heat fusion (heat sealing) is used as the joining method.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Patent Document 3

[0005] The present invention aims to provide a packaging material suitable for such applications, namely, a packaging material that has excellent moldability, maintains the same adhesive strength between layers even after heat fusion of sealant layers to seal the contents, and is free from appearance defects such as lifting between layers. Furthermore, the invention aims to provide a two-component adhesive with excellent moldability and heat resistance, suitable for the manufacture of such packaging materials, as well as laminates and molded products using the same. [Means for solving the problem]

[0006] The present invention relates to a two-component curing adhesive comprising a polyol composition (A) and a polyisocyanate composition (B), wherein the polyol composition (A) comprises a polyester polyol (A1) which is a reaction product of a polycarboxylic acid and a polyhydric alcohol, and in which 30 mol% or more of the polycarboxylic acid is an aromatic polycarboxylic acid, and the polyisocyanate composition (B) comprises a urethane prepolymer (B1) which is a reaction product of a polyol (b1-1) containing a polyether polyol and a polyisocyanate (b1-2), and a trimethylolpropane adduct (B2) of toluene diisocyanate, wherein the proportion of the trimethylolpropane adduct (B2) of toluene diisocyanate in the solid content of the polyisocyanate composition (B) is 10% by mass or more and 85% by mass or less.

[0007] The present invention also relates to a laminate obtained by bonding multiple substrates together using the above-mentioned two-component curing adhesive.

[0008] The present invention also relates to a battery packaging material in which at least an outer base material layer 1, an adhesive layer 2, a metal layer 3, and a sealant layer 4 are sequentially laminated, wherein the adhesive layer 2 is a cured product of the above-mentioned two-component curing adhesive.

[0009] The present invention also relates to a battery container formed from the battery packaging material described above.

[0010] The present invention also relates to a battery using the battery container described above. [Effects of the Invention]

[0011] By using the adhesive of the present invention, it is possible to provide a packaging material that has excellent moldability, maintains the same level of adhesive strength between layers even after heat fusion of sealant layers to seal the contents, and is free from appearance defects such as lifting between layers. [Brief explanation of the drawing]

[0012] [Figure 1] This is an example of a specific embodiment of the present invention, in which an outer base material layer 1, an adhesive layer 2, a metal layer 3, and a sealant layer 4 are sequentially laminated. [Figure 2] This is an example of a specific embodiment of the present invention, in which an outer base material layer 1, an adhesive layer 2, a metal layer 3, an adhesive layer 5, and a sealant layer 4 are sequentially laminated. [Modes for carrying out the invention]

[0013] <Adhesive> The adhesive of the present invention is a two-component curing type adhesive comprising a polyol composition (A) and a polyisocyanate composition (B). The adhesive of the present invention will be described in detail below.

[0014] (Polyol composition (A)) (Polyester polyol (A1)) The polyol composition (A) used in the adhesive of the present invention includes a polyester polyol (A1) which has a polybasic acid or a derivative thereof and a polyhydric alcohol as essential raw materials. Polybasic acids or their derivatives used as raw materials for polyester polyol (A1) include aliphatic polybasic acids such as malonic acid, ethyl malonic acid, dimethyl malonic acid, succinic acid, 2,2-dimethyl succinic acid, succinic anhydride, alkenyl succinic anhydride, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, fumaric acid, maleic acid, maleic anhydride, and itaconic acid;

[0015] Alkyl esterified products of aliphatic polybasic acids such as dimethyl malonate, diethyl malonate, dimethyl succinate, dimethyl glutarate, dimethyl adipate, diethyl pimelate, diethyl sebacate, dimethyl fumarate, diethyl fumarate, dimethyl maleate, diethyl maleate, etc.;

[0016] Alicyclic polybasic acids such as 1,1-cyclopentanedicarboxylic acid, 1,2-cyclopentanedicarboxylic acid, 1,3-cyclopentanedicarboxylic acid, 1,2-cyclohexanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, tetrahydrophthalic anhydride, 4-methylhexahydrophthalic anhydride, hexahydrophthalic anhydride, cyclohexane-1,2,4-tricarboxylic acid-1,2-anhydride, hymic anhydride, het anhydride, etc.;

[0017] Aromatic polybasic acids such as orthophthalic acid, terephthalic acid, isophthalic acid, phthalic anhydride, 1,4-naphthalenedicarboxylic acid, 2,5-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, 2,3-naphthalenedicarboxylic anhydride, naphthalic acid, trimellitic acid, trimellitic anhydride, pyromellitic acid, pyromellitic anhydride, biphenyldicarboxylic acid, 1,2-bis(phenoxy)ethane-p,p'-dicarboxylic acid, benzophenonetetracarboxylic acid, benzophenonetetracarboxylic dianhydride, 5-sodium sulfoisophthalic acid, tetrachlorophthalic anhydride, tetrabromophthalic anhydride, etc.;

[0018] Methyl esterified products of aromatic polybasic acids such as dimethyl terephthalic acid, dimethyl 2,6-naphthalenedicarboxylate, etc.; and the like can be mentioned, and one or more of them can be used in combination.

[0019] As the polyhydric alcohol, a diol or a polyol having three or more functional groups may be used. Examples of the diol include aliphatic diols such as ethylene glycol, diethylene glycol, propylene glycol, 1,3-propanediol, 1,2,2-trimethyl-1,3-propanediol, 2,2-dimethyl-3-isopropyl-1,3-propanediol, 1,4-butanediol, 1,3-butanediol, 3-methyl-1,3-butanediol, 1,5-pentanediol, 1-methyl-1,5-pentanediol, 2-methyl-1,5-pentanediol, 3-methyl 1,5-pentanediol, 2,4-diethyl-1,5-pentanediol, neopentyl glycol, 1,6-hexanediol, 1,7-heptanediol, 2-methyl-1,7-heptanediol, 3-methyl 1,7-heptanediol, 4-methyl-1,7-heptanediol, 1,9-nonanediol, 1,11-undecanediol, 1,13-tridecanediol, 1,15-pentadecanediol, 1,17-heptadecanediol, 1,19-nonadecanediol, 1,4-bis(hydroxymethyl)cyclohexane, 2,2,4-trimethyl-1,3-pentanediol;

[0020] ether glycols such as polyoxyethylene glycol and polyoxypropylene glycol;

[0021] modified polyether diols obtained by ring-opening polymerization of the aliphatic diol and various compounds containing a cyclic ether bond such as ethylene oxide, propylene oxide, tetrahydrofuran, ethyl glycidyl ether, propyl glycidyl ether, butyl glycidyl ether, phenyl glycidyl ether, allyl glycidyl ether;

[0022] lactone-based polyester polyols obtained by polycondensation reaction of the aliphatic diol and various lactones such as lactanoid and ε-caprolactone;

[0023] bisphenols such as bisphenol A and bisphenol F;

[0024] Examples include alkylene oxide adducts of bisphenols obtained by adding ethylene oxide, propylene oxide, etc., to bisphenols such as bisphenol A and bisphenol F.

[0025] Polyols with three or more functions include aliphatic polyols such as trimethylolethane, trimethylolpropane, glycerin, hexanetriol, and pentaerythritol;

[0026] Modified polyether polyols obtained by ring-opening polymerization of the aliphatic polyol with various cyclic ether linkage-containing compounds such as ethylene oxide, propylene oxide, tetrahydrofuran, ethyl glycidyl ether, propyl glycidyl ether, butyl glycidyl ether, phenyl glycidyl ether, and allyl glycidyl ether;

[0027] Examples include lactone-based polyester polyols obtained by polycondensation reactions of the aliphatic polyol with various lactones such as ε-caprolactone.

[0028] In this invention, it is preferable to include a branched alkylenediol as the polyhydric alcohol, as this improves the appearance of the laminate.

[0029] Branched alkylenediols are specifically alkylenediols having a tertiary or quaternary carbon atom in their molecular structure. Examples include 1,2,2-trimethyl-1,3-propanediol, 2,2-dimethyl-3-isopropyl-1,3-propanediol, 3-methyl-1,3-butanediol, 3-methyl-1,5-pentanediol, neopentyl glycol, 1,4-bis(hydroxymethyl)cyclohexane, and 2,2,4-trimethyl-1,3-pentanediol. These can be used individually or in combination of two or more. Among these, neopentyl glycol is particularly preferred from the viewpoint of obtaining a polyester polyol (A1) with excellent moisture and heat resistance.

[0030] In the present invention, polyester polyol (A1) may be a polyester polyurethane polyol, which is obtained by using a polybasic acid or a derivative thereof, a polyhydric alcohol, and a polyisocyanate as essential raw materials. In this case, examples of polyisocyanates used include diisocyanate compounds and polyisocyanate compounds with three or more functions. These polyisocyanates may be used individually or in combination of two or more types.

[0031] Diisocyanate compounds include, for example, aliphatic diisocyanates such as butane-1,4-diisocyanate, hexamethylene diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, 2,4,4-trimethylhexamethylene diisocyanate, xylylene diisocyanate, m-tetramethylxylylene diisocyanate, and lysine diisocyanate;

[0032] Alicyclic diisocyanates such as cyclohexane-1,4-diisocyanate, isophorone diisocyanate, dicyclohexylmethane-4,4'-diisocyanate, 1,3-bis(isocyanate-methyl)cyclohexane, methylcyclohexane diisocyanate, isopropylidene dicyclohexyl-4,4'-diisocyanate, norbornane diisocyanate;

[0033] Examples of aromatic diisocyanates include 1,5-naphthylene diisocyanate, 2,2'-diphenylmethane diisocyanate, 2,4'-diphenylmethane diisocyanate, 4,4'-diphenylmethane diisocyanate, 4,4'-diphenyldimethylmethane diisocyanate, 4,4'-dibenzyle diisocyanate, dialkyldiphenylmethane diisocyanate, tetraalkyldiphenylmethane diisocyanate, 1,3-phenylenediisocyanate, 1,4-phenylenediisocyanate, and tolylene diisocyanate.

[0034] Alternatively, allophanate, biuret, or carbodiimide-modified forms of these diisocyanate compounds can also be used.

[0035] Examples of polyisocyanate compounds with three or more functionalities include adduct-type polyisocyanate compounds having a urethane bond site within the molecule, and nurate-type polyisocyanate compounds having an isocyanurate ring structure within the molecule.

[0036] Adduct-type polyisocyanate compounds having urethane bonding sites within the molecule can be obtained, for example, by reacting a diisocyanate compound with a polyhydric alcohol. Examples of diisocyanate compounds used in this reaction include the various diisocyanate compounds exemplified above, which may be used individually or in combination of two or more. Examples of polyol compounds used in this reaction include the various polyol compounds exemplified as raw materials for polyester polyol (A1), and polyester polyols obtained by reacting a polyhydric alcohol with a polybasic acid, which may be used individually or in combination of two or more.

[0037] Nurate-type polyisocyanate compounds having an isocyanurate ring structure within the molecule can be obtained, for example, by reacting a diisocyanate compound with a monoalcohol and / or diol. Examples of diisocyanate compounds used in this reaction include the various diisocyanate compounds exemplified above, which may be used individually or in combination of two or more. Examples of monoalcohols used in this reaction include hexanol, 2-ethylhexanol, octanol, n-decanol, n-undecanol, n-dodecanol, n-tridecanol, n-tetradecanol, n-pentadecanol, n-heptadecanol, n-octadecanol, n-nonadecanol, eicosanol, 5-ethyl-2-nonanol, trimethylnonyl alcohol, 2-hexyldecanol, 3,9-diethyl-6-tridecanol, 2-isoheptylisoundecanol, 2-octyldodecanol, 2-decyltetradecanol, etc. Examples of diols include aliphatic diols exemplified as raw materials for polyester polyol (A1). These monoalcohols and diols may be used individually or in combination of two or more types.

[0038] Polyester polyol (A1) is a reaction product of a polybasic acid or its derivative and a polyhydric alcohol, and it is preferable that the proportion of the polybasic acid or its derivative having an aromatic ring is 30 mol% or more. This makes it possible to produce an adhesive with excellent storage stability. Furthermore, since moldability and heat resistance are improved, it is more preferable that the proportion of the polybasic acid or its derivative having an aromatic ring is 50 mol% or more, more preferably 70 mol% or more, and more preferably 96 mol% or more. It is also possible that all of the polybasic acid or its derivative is a polybasic acid having an aromatic ring.

[0039] Alternatively, the polyester polyol (A1) may be a reaction product of a polybasic acid or its derivative, a polyhydric alcohol, and a polyisocyanate, and it is preferable that the proportion of the polybasic acid or its derivative having an aromatic ring is 30 mol% or more. This makes it possible to make an adhesive with excellent storage stability. Furthermore, since moldability and heat resistance are improved, it is more preferable that the proportion of the polybasic acid or its derivative having an aromatic ring is 50 mol% or more, more preferably 70 mol% or more, and more preferably 96 mol% or more. All of the polybasic acid or its derivative may be polybasic acids having aromatic rings.

[0040] The hydroxyl value of polyester polyol (A1) is preferably in the range of 1 to 40 mgKOH / g, more preferably 3 mgKOH / g or more, and 30 mgKOH / g or less, as this provides superior adhesive strength.

[0041] The number-average molecular weight (Mn) of polyester polyol (A1) is preferably in the range of 2,000 to 100,000, and more preferably in the range of 2,000 to 50,000, because this provides superior adhesive strength when used in adhesive applications. If the number-average molecular weight is less than 2,000, the crosslinking density in the cured coating film may become too high, resulting in poor appearance and moldability of the laminate. On the other hand, the weight-average molecular weight (Mw) is preferably in the range of 5,000 to 300,000, and more preferably in the range of 10,000 to 200,000.

[0042] In this invention, the weight-average molecular weight (Mw) and number-average molecular weight (Mn) are values ​​measured by gel permeation chromatography (GPC) under the following conditions.

[0043] Measuring device: HLC-8320GPC, manufactured by Tosoh Corporation. Columns; manufactured by Tosoh Corporation: TSKgel 4000HXL, TSKgel 3000HXL, TSKgel 2000HXL, TSKgel 1000HXL Detector; RI (Differential Refractometer) Data processing; Tosoh Corporation Multi-Station GPC-8020 model II Measurement conditions: Column temperature 40°C Solvent: tetrahydrofuran Flow rate 0.35ml / min Standard; monodisperse polystyrene Sample: 100 μl of a tetrahydrofuran solution containing 0.2% by mass (based on resin solids content) filtered through a microfilter.

[0044] The solid content acid value of polyester polyol (A1) is not particularly limited, but is preferably 10.0 mgKOH / g or less. A value of 5.0 mgKOH / g or less is preferable due to superior resistance to humidity and heat. There is also no particular limit to the lower limit of the solid content acid value, but as an example, it is 0.5 mgKOH / g or more. It may also be 0 mgKOH / g.

[0045] The glass transition temperature of the polyester polyol (A1) is not particularly limited, but it is preferably -30°C or higher, and more preferably -20°C or higher, in order to suppress adhesive overflow during dry lamination when manufacturing the laminate. There is no particular upper limit, but it is preferably 110°C or lower, taking into account storage stability and productivity.

[0046] The polyester polyol (A1) used in the present invention may contain two or more polyester polyols with different glass transition temperatures. In this case, it is preferable to include a polyester polyol (A1-1) with a glass transition temperature of -30°C to 20°C and a polyester polyol (A1-2) with a glass transition temperature of 50°C to 110°C. This improves heat resistance and moisture resistance.

[0047] When polyester polyol (A1) contains polyester polyol (A1-1) and polyester polyol (A1-2), it is preferable that the blending ratio is such that the amount of polyester polyol (A1-1) relative to the total amount of polyester polyol (A1-1) and (A1-2) is 50% by mass or more and 99% by mass or less.

[0048] In the present invention, the glass transition temperature refers to the value measured as follows. Using a differential scanning calorimetry system (DSC-7000, manufactured by SII Nanotechnology Co., Ltd., hereinafter referred to as DSC), 5 mg of the sample is heated from room temperature to 200°C at a rate of 10°C / min under a nitrogen stream of 30 mL / min, and then cooled to -80°C at a rate of 10°C / min. The sample is then heated again to 150°C at a rate of 10°C / min, and the DSC curve is measured. The glass transition point is defined as the intersection of a straight line extending from the low-temperature baseline of the measurement results observed in the second heating step to the high-temperature side, and a tangent line drawn at the point where the slope of the curve of the step-like portion of the glass transition is maximum. The temperature at this point is defined as the glass transition temperature. In addition, the temperature is raised to 200°C in the first heating step, but this is sufficient as long as it is a temperature at which the polyester polyol (A1) is sufficiently melted, and should be adjusted as appropriate if 200°C is insufficient. Similarly, the cooling temperature should be adjusted as appropriate if -80°C is insufficient (for example, if the glass transition temperature is lower).

[0049] The polyester polyol (A1) used in the present invention may also preferably include polyester polyol (A1-3) synthesized using a polyhydric alcohol in which the number of carbon atoms in the methylene chain between two hydroxyl groups is 5 to 19 and odd. The methylene chain may be linear or branched with side chains. If the methylene chain includes side chains, the number of carbon atoms in the side chains is not included in the number of carbon atoms in the methylene chain. This makes it possible to obtain a material with excellent adhesion, moldability, and heat resistance.

[0050] When polyester polyol (A1) contains polyester polyol (A1-3), the amount of polyester polyol (A1-3) is preferably 1% by mass or more and 50% by mass or less of polyester polyol (A1).

[0051] In the synthesis of polyester polyol (A1), the reaction between a polybasic acid or its derivative and a polyhydric alcohol, or the reaction between a polybasic acid or its derivative, a polyhydric alcohol, and a polyisocyanate, can be carried out by known methods.

[0052] For example, the reaction between a polybasic acid or its derivative and the polyhydric alcohol can be carried out by polycondensation. Alternatively, the reaction between a polybasic acid or its derivative, the polyhydric alcohol and the polyisocyanate can be carried out by reacting the polyester polyol obtained by reacting the polybasic acid or its derivative with the polyhydric alcohol in the manner described above with the polyisocyanate, in the presence of a known and conventional urethane catalyst as needed, to obtain polyester polyol (A1).

[0053] The esterification reaction between a polybasic acid or its derivative and a polyhydric alcohol involves charging the polybasic acid or its derivative, the polyhydric alcohol, and a polymerization catalyst into a reaction vessel equipped with a stirrer and rectification equipment, and heating the mixture to approximately 130°C at atmospheric pressure while stirring. Subsequently, the reaction temperature is maintained in the range of 130-260°C, and the water produced is removed by distillation while increasing the temperature at a rate of 5-10°C per hour. After esterification for 4-12 hours, the excess polyhydric alcohol is removed by gradually increasing the pressure from atmospheric pressure to a range of 1-300 torr, thereby accelerating the reaction and producing polyester polyol (A1).

[0054] For polymerization catalysts used in esterification reactions, a polymerization catalyst consisting of at least one metal selected from the group consisting of groups 2, 4, 12, 13, 14, and 15 of the periodic table, or a compound of such a metal, is preferred. Examples of polymerization catalysts consisting of such metals or metal compounds include metals such as Ti, Sn, Zn, Al, Zr, Mg, Hf, and Ge, and compounds of these metals, more specifically titanium tetraisopropoxide, titanium tetrabutoxide, titanium oxyacetylacetonate, tin octanoate, 2-ethylhexanotin, zinc acetylacetonate, zirconium tetrachloride, zirconium tetrachloride tetrahydrofuran complex, hafnium tetrachloride, hafnium tetrachloride tetrahydrofuran complex, germanium oxide, and tetraethoxygermanium.

[0055] Commercially available polymerization catalysts that can be used in esterification reactions include the Orgatics TA series, TC series, ZA series, ZC series, and AL series from Matsumoto Fine Chemical Co., Ltd., as well as organotin catalysts, inorganic metal catalysts, and inorganic tin compounds from Nitto Chemical Co., Ltd.

[0056] The amount of these polymerization catalysts used is not particularly limited as long as the esterification reaction can be controlled and a polyester polyol (A1) of good quality can be obtained. As an example, it is 10 to 1,000 ppm relative to the total amount of the polybasic acid or its derivative and the polyhydric alcohol, preferably 20 to 800 ppm. It is even more preferable to use 30 to 500 ppm to suppress discoloration of the polyester polyol (A1).

[0057] Furthermore, polyester polyurethane polyols can be obtained by extending the chains of the polyester polyol obtained by the method described above with a polyisocyanate. Specifically, the manufacturing method involves placing the polyester polyol, polyisocyanate, a chain extension catalyst, and a suitable solvent for the polyester polyol and polyisocyanate (as needed) into a reaction vessel and stirring at a reaction temperature of 60-90°C. The reaction is carried out until substantially no isocyanate groups derived from the polyisocyanate used remain to obtain the polyester polyurethane polyol used in this invention.

[0058] As the chain elongation catalyst, any known and commonly used catalyst for urethane formation can be used. Specifically, examples include organotin compounds, tin organic carboxylates, lead carboxylates, bismuth carboxylates, titanium compounds, zirconium compounds, etc., which can be used alone or in combination. The amount of the chain elongation catalyst used should be sufficient to adequately promote the reaction between the polyester polyol and the polyisocyanate. Specifically, it is preferable to use 5.0% by mass or less relative to the total amount of polyester polyol and polyisocyanate. To suppress hydrolysis and discoloration of the resin by the catalyst, it is more preferable to use 1.0% by mass or less. Furthermore, these chain elongation catalysts may be used considering their action as curing catalysts for the polyol composition (A) and polyisocyanate composition (B) described later.

[0059] One way to confirm the remaining amount of isocyanate groups is by infrared absorption spectroscopy, which measures the absorption spectrum originating from the isocyanate groups at 2260 cm⁻¹. -1This includes checking for the presence or absence of absorption peaks in the vicinity, and quantifying the isocyanate group by titration.

[0060] Suitable solvents for the production of polyester polyurethane polyols include acetone, methyl acetate, ethyl acetate, butyl acetate, dimethyl carbonate, methyl ethyl ketone, methyl isobutyl ketone, propylene glycol monomethyl ether acetate, toluene, and xylene. These may be used individually or in combination of two or more.

[0061] (Polyol (A2)) The polyol composition (A) may contain polyols (A2) other than polyester polyol (A1) as long as the effects of the present invention are not impaired. Examples of polyols (A2) include polycarbonate polyols and polyether polyols.

[0062] The number-average molecular weight (Mn) of the polycarbonate polyol is preferably in the range of 300 to 2,000, as this results in an adhesive with high adhesion to various substrates and excellent resistance to humidity and heat. Its hydroxyl value is preferably in the range of 30 to 250 mgKOH / g, and more preferably in the range of 40 to 200 mgKOH / g. Furthermore, the polycarbonate polyol is preferably a polycarbonate diol. As this results in an adhesive with high adhesion to various substrates and excellent resistance to humidity and heat, the blending ratio of the total amount of polyester polyol (A1) to the polycarbonate polyol is preferably such that the total mass of polyester polyol (A1) is 30% by mass or more, and more preferably 60% by mass or more, relative to the total mass of both.

[0063] The number-average molecular weight (Mn) of the polyether polyol is preferably in the range of 300 to 2,000, as this results in an adhesive with high adhesion to various substrates and excellent resistance to humidity and heat. Its hydroxyl value is preferably in the range of 40 to 250 mgKOH / g, and more preferably in the range of 50 to 200 mgKOH / g. Furthermore, the polyether polyol compound is preferably a polyetherdiol. The ratio of the total amount of polyester polyol (A1) to the polyether polyol is preferably such that the total mass of polyester polyol (A1) is 30% by mass or more, and more preferably 60% by mass or more, relative to the total mass of both, as this results in an adhesive with high adhesion to various substrates and excellent resistance to humidity and heat.

[0064] (Other resins (A3)) The polyol composition (A) may contain a resin (A3) other than polyester polyol (A1) and polyol (A2). When using resin (A3), it is preferable to use it in an amount of 50% by mass or less, and more preferably 30% by mass or less, relative to the total mass of solids in the polyol composition (A). Specific examples of resin (A3) include epoxy resins. Examples of epoxy resins include bisphenol-type epoxy resins such as bisphenol A-type epoxy resin and bisphenol F-type epoxy resin; biphenyl-type epoxy resins such as biphenyl-type epoxy resin and tetramethylbiphenyl-type epoxy resin; and dicyclopentadiene-phenol addition reaction type epoxy resins. These may be used individually or in combination of two or more types. Among these, bisphenol-type epoxy resin is preferred because it provides high adhesion to various substrates and excellent resistance to humidity and heat.

[0065] The number-average molecular weight (Mn) of the epoxy resin is preferably in the range of 300 to 2,000, as this results in an adhesive with high adhesion to various substrates and excellent resistance to humidity and heat. Furthermore, the epoxy equivalent is preferably in the range of 150 to 1,000 g / equivalent.

[0066] When using epoxy resin, the ratio of the total amount of polyester polyol (A1) to the epoxy resin is such that the total mass of polyester polyol (A1) is in the range of 30 to 99.5% by mass, and more preferably in the range of 60 to 99% by mass, relative to the total mass of both materials, in order to produce an adhesive with high adhesion to various substrates and excellent resistance to moisture and heat.

[0067] (Adhesion agent) The polyol composition (A) may contain a tackifier. Examples of tackifiers include rosin-based or rosin ester-based tackifiers, terpene-based or terpene phenol-based tackifiers, saturated hydrocarbon resins, coumarone-based tackifiers, coumarone-indene-based tackifiers, styrene-based tackifiers, xylene-based tackifiers, phenol-based tackifiers, petroleum-based tackifiers, and ketone-based tackifiers. Ketone-based tackifiers and rosin-based or rosin ester-based tackifiers are preferred, and ketone-based tackifiers are more preferred. These may be used individually or in combination of two or more types. When a tackifier is used, the total mass of polyester polyol (A1) is preferably 80 to 99.99% by mass, and more preferably 85 to 99.9% by mass, relative to the total mass of polyester polyol (A1) and the tackifier.

[0068] Examples of rosin-based or rosin ester-based products include polymerized rosin, disproportionated rosin, hydrogenated rosin, maleated rosin, fumarated rosin, and their glycerin esters, pentaerythritol esters, methyl esters, ethyl esters, butyl esters, ethylene glycol esters, diethylene glycol esters, and triethylene glycol esters.

[0069] Examples of terpene or terpenephenol compounds include low-polymerization terpenes, α-pinene polymers, β-pinene polymers, terpenephenol compounds, aromatically modified terpenes, and hydrogenated terpenes.

[0070] Examples of petroleum resins include petroleum resins obtained by polymerizing petroleum fractions with 5 carbon atoms from pentene, pentadiene, isoprene, etc., petroleum resins obtained by polymerizing petroleum fractions with 9 carbon atoms from indene, methylindene, vinyltoluene, styrene, α-methylstyrene, β-methylstyrene, etc., C5-C9 copolymer petroleum resins obtained from the above various monomers and petroleum resins obtained by hydrogenating these, petroleum resins obtained from cyclopentadiene, dicyclopentadiene; and hydrides of these petroleum resins; and modified petroleum resins obtained by modifying these petroleum resins with maleic anhydride, maleic acid, fumaric acid, (meth)acrylic acid, phenol, etc.

[0071] As phenolic resin systems, condensates of phenols and formaldehyde can be used. Examples of phenols include phenol, m-cresol, 3,5-xylenol, p-alkylphenol, and resorcinol. Examples include resols obtained by addition reactions of these phenols with formaldehyde using an alkaline catalyst, and novolacs obtained by condensation reactions using an acid catalyst. Rosinphenol resins obtained by adding phenol to rosin using an acid catalyst and then thermal polymerization can also be given as examples.

[0072] While well-known and commonly used ketone resins can be cited, formaldehyde resins, cyclohexanone-formaldehyde resins, and ketonealdehyde condensation resins can be suitably used.

[0073] While tackifiers with various softening points can be obtained, from the viewpoint of compatibility when mixed with other resins constituting the polyol composition (A), color tone, and thermal stability, ketone resin-based tackifiers with a softening point of 70 to 160°C, preferably 80 to 100°C, or rosin-based resins and their hydrogenated derivatives with a softening point of 80 to 160°C, preferably 90 to 110°C, are preferred, and ketone resin-based tackifiers with a softening point of 70 to 160°C, preferably 80 to 100°C, are more preferred. Furthermore, ketone resin-based tackifiers and hydrogenated rosin-based tackifiers with an acid value of 2 to 20 mg KOH / g and a hydroxyl value of 10 mg KOH / g or less are preferred, and ketone resin-based tackifiers with an acid value of 2 to 20 mg KOH / g and a hydroxyl value of 10 mg KOH / g or less are more preferred.

[0074] (Polyisocyanate composition (B)) (Urethane prepolymer (B1)) The polyisocyanate composition (B) used in the present invention comprises a urethane prepolymer (B1) and a trimethylolpropane adduct of toluene diisocyanate (B2). Urethane prepolymers are reaction products of polyol (b1-1) and polyisocyanate (b1-2), and polyol (b1-1) includes a polyether polyol as an essential component.

[0075] Polyether polyols used in the synthesis of urethane prepolymer (B1) include ethylene glycol, diethylene glycol, propylene glycol, 1,3-propanediol, 1,2,2-trimethyl-1,3-propanediol, 2,2-dimethyl-3-isopropyl-1,3-propanediol, 1,4-butanediol, 1,3-butanediol, 3-methyl-1,3-butanediol, 1,5-pentanediol, 1-methyl-1,5-pentanediol, 2-methyl-1,5-pentanediol, 3-methyl-1,5-pentanediol, 2,4-diethyl-1,5-pentanediol, neopentyl glycol, 1,6-hexanediol, 1,7-heptanediol, 2-methyl-1,7-heptanediol, 3-methyl-1,7-heptanediol, 4-methyl-1,7-heptanediol, Examples of polyether polyols obtained by ring-opening polymerization of aliphatic polyols such as 1,9-nonanediol, 1,11-undecanediol, 1,13-tridecanediol, 1,15-pentadecanediol, 1,17-heptadecanediol, 1,19-nonadecanediol, 1,4-bis(hydroxymethyl)cyclohesane, 2,2,4-trimethyl-1,3-pentanediol, trimethylolethane, trimethylolpropane, glycerin, hexanetriol, and pentaerythritol with various cyclic ether linkage-containing compounds such as ethylene oxide, propylene oxide, tetrahydrofuran, ethyl glycidyl ether, propyl glycidyl ether, butyl glycidyl ether, phenyl glycidyl ether, and allyl glycidyl ether are given, and can be used individually or in combination of two or more.

[0076] The polyether polyol used in the synthesis of the urethane prepolymer (B1) preferably has a number average molecular weight of 400 to 3000, and more preferably has a number average molecular weight of 400 to 2000.

[0077] Polyol (b1-1) may contain polyols other than polyether polyols. As polyols other than polyether polyols, those similar to those exemplified as polyhydric alcohols used as raw materials for polyester polyol (A1) can be used. When polyol (b1-1) contains polyols other than polyether polyols, the polyether polyol content in polyol (b1-1) is preferably 80% by mass or more, and more preferably 90% by mass or more.

[0078] As for the polyisocyanate (b1-2), the same as those exemplified as raw materials when the polyester polyol (A1) is a polyester polyurethane polyol can be used. The polyisocyanate (b1-2) preferably contains an aromatic polyisocyanate, and more preferably contains at least one selected from 2,2'-diphenylmethane diisocyanate, 2,4'-diphenylmethane diisocyanate, 4,4'-diphenylmethane diisocyanate, and tolylene diisocyanate, and more preferably contains at least one selected from 2,2'-diphenylmethane diisocyanate, 2,4'-diphenylmethane diisocyanate, and 4,4'-diphenylmethane diisocyanate.

[0079] When the polyisocyanate (b1-2) contains an aromatic polyisocyanate, the amount can be adjusted as appropriate, but as an example, it is preferably 50% by mass or more and 95% by mass or less, and more preferably 60% by mass or more and 90% by mass or less.

[0080] Furthermore, the polyisocyanate (b1-2) may also preferably include a nurate-type polyisocyanate compound of diisocyanate. The diisocyanate used in this case is preferably at least one selected from aliphatic diisocyanates or alicyclic diisocyanates, and more preferably an aliphatic diisocyanate.

[0081] When polyisocyanate (b1-2) contains a nurate-type polyisocyanate compound, the amount can be adjusted as appropriate, but as an example, it is preferably 5% by mass or more and 50% by mass or less, and more preferably 10% by mass or more and 40% by mass or less.

[0082] The urethane prepolymer (B1) is obtained by reacting a polyol (b1-1) and a polyisocyanate (b1-2) under conditions in which the isocyanate groups contained in the polyisocyanate (b1-2) are in excess of the hydroxyl groups contained in the polyol (b1-1). When the number of moles of hydroxyl groups contained in the polyol (b1-1) is [OH] and the number of moles of isocyanate groups contained in the polyisocyanate (b1-2) is [NCO], it is preferable to react under conditions where [NCO] / [OH] is 1.5 to 20.

[0083] (Trimethylolpropane adduct of toluene diisocyanate (B2)) The polyisocyanate composition (B) used in the present invention contains a trimethylolpropane adduct (B2) of toluene diisocyanate (hereinafter also simply referred to as adduct (B2)) as an essential component. Furthermore, the proportion of adduct (B2) in the solid content of the polyisocyanate composition (B) is 10% by mass or more and 85% by mass or less. This makes it possible to produce an adhesive with excellent properties such as moldability and heat resistance.

[0084] When obtaining an adhesive with excellent adhesive strength at room temperature and at high temperatures, it is preferable that the proportion of adduct material (B2) in the solid content of the polyisocyanate composition (B) be 10% by mass or more and less than 50% by mass. When obtaining an adhesive with an excellent balance of adhesive strength at room temperature and high temperatures, as well as moldability and heat resistance, it is preferable that the proportion of adduct material (B2) in the solid content of the polyisocyanate composition (B) be 50% by mass or more and 85% by mass or less.

[0085] (Polyisocyanate compound (B3)) The polyisocyanate composition (B) used in the present invention may contain a polyisocyanate compound (B3) other than the urethane prepolymer (B1) and the adduct (B2). Such a polyisocyanate (B3) can be the same as those exemplified as raw materials when the polyester polyol (A1) is a polyester polyurethane polyol. Examples of polyisocyanate compounds (B3) include adducts, nurates, biuretes, carbodiimides, and oligomers of aromatic diisocyanates.

[0086] When the polyisocyanate composition (B) contains a polyisocyanate compound (B3), it is preferable that the content of the polyisocyanate compound (B3) in relation to the solid content of the polyisocyanate composition (B) is 10% by mass or less.

[0087] The polyisocyanate composition (B) is preferably adjusted so that its NCO% is between 2% and 30%. This allows for the creation of an adhesive with an excellent balance of various properties, such as adhesion, heat resistance, and moldability.

[0088] (Organic solvents) The adhesive of the present invention may be in either a solvent-type or solvent-free form, but it is more preferable to use it in a solvent-type form. In this invention, a "solvent-type" adhesive refers to a form used in a method where the adhesive is applied to a substrate, heated in an oven or the like to volatilize the organic solvent in the coating, and then bonded to another substrate—a method known as dry lamination. Either one or both of the polyol composition (A) and the polyisocyanate composition (B) contain a highly soluble organic solvent capable of dissolving the polyol composition (A) or polyisocyanate composition (B) used in this invention. The organic solvent used as a reaction medium during the production of the components of the polyol composition (A) or polyisocyanate composition (B) may also be used as a diluent during painting. Examples of highly soluble organic solvents include esters such as methyl acetate, ethyl acetate, butyl acetate, dimethyl carbonate, and cellosolve acetate; ketones such as acetone, methyl ethyl ketone, isobutyl ketone, and cyclohexanone; ethers such as tetrahydrofuran and dioxane; aromatic hydrocarbons such as toluene and xylene; halogenated hydrocarbons such as methylene chloride and ethylene chloride; dimethyl sulfoxide and dimethyl sulfamide.

[0089] In this specification, "solvent-free" adhesives refer to adhesives used in the so-called non-solvent laminating method, in which the polyol composition (A) and polyisocyanate composition (B) substantially do not contain highly soluble organic solvents as described above, particularly ethyl acetate or methyl ethyl ketone, and the adhesive is applied to a substrate and then bonded to another substrate without the step of heating in an oven or the like to volatilize the solvent. If trace amounts of organic solvent remain in the polyol composition (A) or polyisocyanate composition (B) due to the organic solvent used as a reaction medium during the production of the components of the polyol composition (A) or polyisocyanate composition (B) or their raw materials, it is understood that the adhesive is substantially solvent-free. Furthermore, if the polyol composition (A) contains a low molecular weight alcohol, the low molecular weight alcohol reacts with the polyisocyanate composition (B) to become part of the coating film, so it is not necessary to volatilize it after application. Therefore, such forms are also treated as solvent-free adhesives.

[0090] (Adhesives and other components) The adhesive of the present invention may contain components other than those listed above. These components may be added beforehand to either the polyol composition (A) or the polyisocyanate composition (B), or to both, or they may be added when mixing the polyol composition (A) and the polyisocyanate composition (B).

[0091] The adhesive of the present invention may contain, for example, known phosphoric acids or their derivatives. This further improves the initial adhesion of the adhesive and eliminates problems such as tunneling.

[0092] Phosphates or their derivatives used here include, for example, phosphates such as hypophosphorous acid, phosphorous acid, orthophosphoric acid, and subphosphoric acid; condensed phosphates such as metaphosphoric acid, pyrophosphoric acid, tripolyphosphoric acid, polyphosphoric acid, and ultraphosphoric acid; for example, monomethyl orthophosphoric acid, monoethyl orthophosphoric acid, monopropyl orthophosphoric acid, monobutyl orthophosphoric acid, mono-2-ethylhexyl orthophosphoric acid, monophenyl orthophosphoric acid, monomethyl phosphate, monoethyl phosphate, monopropyl phosphate, monobutyl phosphate, mono-2-ethylhexyl phosphate, and monophosphoric acid. Examples include mono- and diesterified compounds of nophenyl, di-2-ethylhexyl orthophosphate, dimethyl diphenyl orthophosphate, diethyl phosphate, dipropyl phosphate, dibutyl phosphate, di-2-ethylhexyl phosphate, and diphenyl phosphate; mono- and diesterified compounds of condensed phosphoric acid and alcohols; for example, those obtained by adding epoxy compounds such as ethylene oxide and propylene oxide to the aforementioned phosphoric acids; and epoxy phosphate esters obtained by adding the aforementioned phosphoric acids to aliphatic or aromatic diglycidyl ethers.

[0093] The above-mentioned phosphoric acids or their derivatives may be used individually or in combination of two or more types. The method of inclusion is simply mixing them in.

[0094] Furthermore, an adhesion promoter may be used in the adhesive of the present invention. Examples of adhesion promoters include silane coupling agents, titanate-based coupling agents, aluminum-based coupling agents, epoxy resins, and the like.

[0095] Examples of silane coupling agents include aminosilanes such as γ-aminopropyltriethoxysilane, γ-aminopropyltrimethoxysilane, N-β(aminoethyl)-γ-aminopropyltrimethoxysilane, N-β(aminoethyl)-γ-aminopropyltrimethyldimethoxysilane, and N-phenyl-γ-aminopropyltrimethoxysilane; epoxysilanes such as β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, and γ-glycidoxypropyltriethoxysilane; vinylsilanes such as vinyltris(β-methoxyethoxy)silane, vinyltriethoxysilane, vinyltrimethoxysilane, and γ-methacryloxypropyltrimethoxysilane; and hexamethyldisilazane and γ-mercaptopropyltrimethoxysilane.

[0096] Examples of titanate-based coupling agents include tetraisopropoxytitanium, tetra-n-butoxytitanium, butyl titanate dimer, tetrastearyl titanate, titanium acetylacetonate, titanium lactate, tetraoctylene glycol titanate, titanium lactate, and tetrastearoxititanium.

[0097] Examples of aluminum-based coupling agents include acetalkoxyaluminum diisopropylate.

[0098] It is preferable to use a silane coupling agent as the adhesion promoter. Furthermore, the content (solids) of the adhesion promoter is preferably 0.1 parts by mass or more, more preferably 0.3 parts by mass or more, more preferably 0.5 parts by mass or more, and even more preferably 0.7 parts by mass or more, per 100 parts by mass of the solids of the polyol composition (A). Furthermore, the content (solids) of the adhesion promoter is preferably 10 parts by mass or less, more preferably 8 parts by mass or less, and even more preferably 5 parts by mass or less, per 100 parts by mass of the solids of the polyol composition (A).

[0099] The adhesive of the present invention may further contain various additives such as ultraviolet absorbers, antioxidants, silicone-based additives, fluorine-based additives, rheology control agents, defoaming agents, antistatic agents, and antifogging agents.

[0100] (composition ratio) In the adhesive of the present invention, the mixing ratio of the polyol composition (A) and the polyisocyanate composition (B) is preferably such that the ratio [NCO] / [OH], which is the total number of moles [OH] of hydroxyl groups contained in the polyol composition (A) to the number of moles [NCO] of isocyanate groups contained in the polyisocyanate composition (B), is in the range of 1.5 to 15. This results in a two-component adhesive with excellent moldability, heat resistance, and other properties. It is more preferable that [NCO] / [OH] is between 5 and 10, and even more preferable that it is between 5 and 8.

[0101] The adhesive of the present invention is not particularly limited in its applications, but because it has excellent adhesive strength, processability, heat resistance, etc., it can be suitably used, for example, in battery packaging materials.

[0102] <Laminate> The laminate of the present invention is obtained by bonding multiple substrates together using the adhesive of the present invention by dry lamination or non-solvent lamination. Examples of substrates include paper, olefin resins, acrylonitrile-butadiene-styrene copolymers (ABS resins), polyvinyl chloride resins, fluororesins, poly(meth)acrylic resins, carbonate resins, polyamide resins, polyimide resins, polyphenylene ether resins, polyphenylene sulfide resins, synthetic resin films obtained from polyester resins, copper foil, metal foils such as aluminum foil, and the like.

[0103] The film thickness of the substrate is not particularly limited and can be selected from, for example, 10 to 400 μm. To improve the adhesion between the substrate and the adhesive, surface treatment may be performed on the surface of the substrate to which the adhesive is applied. Examples of such surface treatments include corona treatment, plasma treatment, ozone treatment, flame treatment, and radiation treatment.

[0104] <Battery packaging material> As shown in Figure 1, the battery packaging material consists of a laminate in which at least an outer base layer 1, an adhesive layer 2, a metal layer 3, and a sealant layer 4 are sequentially laminated. In the battery packaging material of the present invention, the outer base layer 1 is the outermost layer, and the sealant layer 4 is the innermost layer. That is, during battery assembly, the sealant layers 4 located around the periphery of the battery element are heat-fused together to seal the battery element, thereby sealing the battery element. The adhesive of the present invention is used in the adhesive layer 2. Furthermore, as shown in Figure 2, the battery packaging material of the present invention may optionally have an adhesive layer 5 between the metal layer 3 and the sealant layer 4 for the purpose of improving their adhesion.

[0105] (Outer layer side base material layer 1) In the battery packaging material of the present invention, the outer layer base material layer 1 is the outermost layer. The material forming the outer layer base material layer 1 is not particularly limited as long as it has insulating properties, and examples include polyester resin, polyamide resin, epoxy resin, acrylic resin, fluororesin, polyurethane resin, silicon resin, phenolic resin, and resin films such as mixtures and copolymers thereof. Among these, polyester resin and polyamide resin are preferred, and biaxially oriented polyester resin and biaxially oriented polyamide resin are more preferred. Specific examples of polyester resin include polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polybutylene naphthalate, copolymer polyester, and polycarbonate. Specific examples of polyamide resin include nylon 6, nylon 6,6, copolymers of nylon 6 and nylon 6,6, nylon 6,10, and polymetaxylylene adipamide (MXD6).

[0106] The outer layer substrate layer 1 may be formed from a single resin film, but to improve pinhole resistance and insulation, it may be formed from a multilayer of two or more resin films, for example, a polyethylene terephthalate film and a polyamide film. When the outer layer substrate layer 1 is formed from a multilayer resin film, the resin films can be laminated together via an adhesive component such as an adhesive or adhesive resin, and the type and amount of adhesive component used are the same as in the case of adhesive layer 2 or adhesive layer 5 described later. The method for laminating two or more resin films is not particularly limited and known methods can be used, such as dry lamination and sand lamination, with dry lamination being preferred. When laminating by dry lamination, it is preferable to use an adhesive as the adhesive layer. In this case, the thickness of the adhesive layer is, for example, about 0.5 to 10 μm.

[0107] The thickness of the outer base material layer 1 is not particularly limited as long as the battery packaging material satisfies the above physical properties, but for example, it is about 10 to 50 μm, preferably about 15 to 35 μm. When using polyester film, the thickness is preferably 9 μm to 50 μm, and when using polyamide film, the thickness is preferably 10 μm to 50 μm. This ensures sufficient strength as a packaging material, reduces stress during stretch molding and deep drawing, and improves moldability.

[0108] (metal layer 3) In battery packaging materials, the metal layer 3 is a layer that not only improves the strength of the battery packaging material but also functions as a barrier layer to prevent water vapor, oxygen, light, etc. from entering the inside of the battery. Specifically, examples of metals that make up the metal layer 3 include aluminum, stainless steel, and titanium, with aluminum being preferred. The metal layer 3 can be formed by metal foil or metal vapor deposition, and it is preferable to form it by metal foil, and even more preferable to form it by aluminum foil. Furthermore, it is preferable that at least one surface, preferably both surfaces, of the metal layer 3 be chemically treated to stabilize adhesion and prevent dissolution and corrosion. Here, chemical treatment refers to a treatment that forms an acid-resistant film on the surface of the metal layer.

[0109] The thickness of the metal layer 3 is not particularly limited as long as the battery packaging material satisfies the above physical properties, but for example, it can be about 10 to 50 μm, preferably about 25 to 45 μm.

[0110] (Sealant layer 4) In the battery packaging material of the present invention, the sealant layer 4 is the innermost layer and is a layer that seals the battery elements by heat-sealing the sealant layers together during battery assembly.

[0111] The resin component used in the sealant layer 4 is not particularly limited as long as it is heat-sealable, but examples include polyolefins, cyclic polyolefins, carboxylic acid-modified polyolefins, and carboxylic acid-modified cyclic polyolefins.

[0112] The aforementioned polyolefins include, specifically, polyethylene such as low-density polyethylene, medium-density polyethylene, high-density polyethylene, and linear low-density polyethylene; polypropylene such as homopolypropylene, block copolymers of polypropylene (e.g., block copolymer of propylene and ethylene), and random copolymers of polypropylene (e.g., random copolymer of propylene and ethylene); and ethylene-butene-propylene terpolymers; and the like. Among these polyolefins, polyethylene and polypropylene are preferred.

[0113] The cyclic polyolefin is a copolymer of an olefin and a cyclic monomer. Examples of olefins that are constituent monomers of the cyclic polyolefin include ethylene, propylene, 4-methyl-1-pentene, styrene, butadiene, isoprene, and the like. Examples of cyclic monomers that are constituent monomers of the cyclic polyolefin include cyclic alkenes such as norbornene; specifically, examples of cyclic dienes such as cyclopentadiene, dicyclopentadiene, cyclohexadiene, and norbornadiene. Among these polyolefins, cyclic alkenes are preferred, and norbornene is more preferred.

[0114] The carboxylic acid-modified polyolefin is a polymer obtained by modifying the polyolefin by block polymerization or graft polymerization with a carboxylic acid. Examples of carboxylic acids used for modification include maleic acid, acrylic acid, itaconic acid, crotonic acid, maleic anhydride, and itaconic anhydride.

[0115] The carboxylic acid-modified cyclic polyolefin is a polymer obtained by copolymerizing a portion of the monomers constituting the cyclic polyolefin with an α,β-unsaturated carboxylic acid or its anhydride, or by block polymerization or graft polymerization of an α,β-unsaturated carboxylic acid or its anhydride to the cyclic polyolefin. The cyclic polyolefin to be modified with carboxylic acid is the same as described above. Furthermore, the carboxylic acid used for modification is the same as that used for modifying the acid-modified cycloolefin copolymer.

[0116] The sealant layer 4 may be formed by a single resin component, or by a blended polymer combining two or more resin components. Furthermore, the sealant layer 4 may be formed as a single layer, or it may be formed as two or more layers made of the same or different resin components.

[0117] Furthermore, the thickness of the sealant layer 4 is not particularly limited as long as the battery packaging material satisfies the above physical properties, but for example, it is about 10 to 100 μm, preferably about 20 to 90 μm.

[0118] (adhesive layer 5) In the battery packaging material of the present invention, the adhesive layer 5 is a layer provided between the metal layer 3 and the sealant layer 4 as needed in order to firmly bond them together.

[0119] The adhesive layer 5 is formed by an adhesive capable of bonding the metal layer 3 and the sealant layer 4. Examples of adhesives that can be used for the adhesive layer 5 include an adhesive combining a polyolefin resin and a polyfunctional isocyanate, an adhesive combining a polyol and a polyfunctional isocyanate, a modified polyolefin resin, and an adhesive containing a heterocyclic compound and a curing agent. Alternatively, the adhesive layer 5 can be formed by melt-extruding an adhesive such as acid-modified polypropylene onto the metal layer using a T-die extruder, and the sealant layer 4 can be placed on top of the adhesive layer 5 to bond the metal layer 3 and the sealant layer 4 together. If both adhesive layer 2 and adhesive layer 5 require aging, they can be aged together. The aging temperature should be between room temperature and 90°C, which will complete curing and develop moldability in 2 days to 2 weeks.

[0120] The thickness of the adhesive layer 5 is not particularly limited as long as the battery packaging material satisfies the above physical properties, but for example, it is about 0.5 to 50 μm, preferably about 2 to 30 μm.

[0121] (Coating layer 6) In the battery packaging material of the present invention, a coating layer 6 may be provided on the outer base layer 1 (on the opposite side of the outer base layer 1 from the metal layer 3) as needed, for the purpose of improving design, electrolyte resistance, abrasion resistance, and moldability. The coating layer 6 is the outermost layer when the battery is assembled.

[0122] The coating layer 6 can be formed from, for example, polyvinylidene chloride, polyester resin, urethane resin, acrylic resin, epoxy resin, etc., and is preferably formed from a two-component curing resin. Examples of two-component curing resins for forming the coating layer 6 include two-component curing urethane resin, two-component curing polyester resin, and two-component curing epoxy resin. A matting agent may also be incorporated into the coating layer 6.

[0123] Examples of matting agents include fine particles with a particle size of approximately 0.5 nm to 5 μm. The material of the matting agent is not particularly limited, but examples include metals, metal oxides, inorganic substances, and organic substances. The shape of the matting agent is also not particularly limited, but examples include spherical, fibrous, plate-like, amorphous, and balloon-like shapes. Specific examples of matting agents include talc, silica, graphite, kaolin, montmorilloid, montmorillonite, synthetic mica, hydrotalcite, silica gel, zeolite, aluminum hydroxide, magnesium hydroxide, zinc oxide, magnesium oxide, aluminum oxide, neodymium oxide, antimony oxide, titanium dioxide, cerium oxide, calcium sulfate, barium sulfate, calcium carbonate, calcium silicate, lithium carbonate, calcium benzoate, calcium oxalate, magnesium stearate, carbon black, carbon nanotubes, high-melting-point nylon, cross-linked acrylic, cross-linked styrene, cross-linked polyethylene, benzoguanamine, gold, aluminum, copper, and nickel. These matting agents may be used individually or in combination of two or more. Among these matting agents, silica, barium sulfate, and titanium dioxide are preferred from the viewpoint of dispersion stability and cost. In addition, the matting agent may be subjected to various surface treatments such as insulating treatment and high dispersibility treatment.

[0124] The method for forming the coating layer 6 is not particularly limited, but one example is to apply a two-component curable resin for forming the coating layer 6 onto one surface of the outer layer substrate layer 1. If a matting agent is to be incorporated, the matting agent can be added to the two-component curable resin, mixed, and then applied.

[0125] (Method of manufacturing battery packaging material) The method for manufacturing the battery packaging material of the present invention is not particularly limited as long as a laminate is obtained by stacking layers of a predetermined composition, but the following methods are examples.

[0126] First, a laminate (hereinafter sometimes referred to as "laminated body A") is formed by sequentially stacking an outer base material layer 1, an adhesive layer 2, and a metal layer 3. Specifically, laminate A can be formed by a dry lamination method in which the adhesive of the present invention is applied and dried on the outer base material layer 1 or, if necessary, on the metal layer 3 whose surface has been chemically treated, using a coating method such as extrusion, gravure coating, or roll coating, and then the metal layer 3 or the outer base material layer 1 is laminated and the adhesive layer 2 is cured.

[0127] Next, a sealant layer 4 is laminated onto the metal layer 3 of laminate A. When directly laminating the sealant layer 4 onto the metal layer 3, the resin components constituting the sealant layer 4 can be applied to the metal layer 3 of laminate A by methods such as gravure coating or roll coating. Furthermore, when an adhesive layer 5 is provided between the metal layer 3 and the sealant layer 4, examples of methods include laminating the adhesive layer 5 and the sealant layer 4 on the metal layer 3 of the laminate A by co-extrusion (co-extrusion lamination method), separately forming a laminate of the adhesive layer 5 and the sealant layer 4 and laminating this on the metal layer 3 of the laminate A by thermal lamination, laminating an adhesive for forming the adhesive layer 5 on the metal layer 3 of the laminate A by extrusion, solution coating, high-temperature drying and baking, etc., and then laminating a pre-formed sheet-like sealant layer 4 on this adhesive layer 5 by thermal lamination, or pouring molten adhesive layer 5 between the metal layer 3 of the laminate A and the pre-formed sheet-like sealant layer 4, thereby bonding the laminate A and the sealant layer 4 via the adhesive layer 5 (sand lamination method).

[0128] When a coating layer 6 is provided, the coating layer 6 is laminated on the surface of the outer base layer 1 opposite to the metal layer 3. The coating layer 6 is formed, for example, by applying the resin used to form the coating layer 6 to the surface of the outer base layer 1. The order of the steps of laminating the metal layer 3 on the surface of the outer base layer 1 and laminating the coating layer 6 on the surface of the outer base layer 1 is not particularly limited. For example, the coating layer 6 may be formed on the surface of the outer base layer 1, and then the metal layer 3 may be formed on the surface of the outer base layer 1 opposite to the coating layer 6.

[0129] As described above, a laminate is formed consisting of a coating layer 6 (provided as needed), an outer substrate layer 1, an adhesive layer 2, a metal layer 3 (with a chemically treated surface as needed), an adhesive layer 5 (provided as needed), and a sealant layer 4. In order to strengthen the adhesion between the adhesive layer 2 and the adhesive layer 5 (provided as needed), the laminate may be subjected to further heat treatment such as a hot roll contact method, a hot air method, or a near or far infrared method. Examples of such heat treatment conditions include 150 to 250°C for 1 to 5 minutes.

[0130] In the battery packaging material of the present invention, each layer constituting the laminate may be subjected to surface activation treatments such as corona treatment, blast treatment, oxidation treatment, or ozone treatment as necessary in order to improve or stabilize film-forming properties, lamination processing, and suitability for secondary processing of the final product (pouching, embossing).

[0131] <Battery container> The battery container of the present invention can be obtained by using the aforementioned battery packaging material and molding it such that the outer base material layer 1 forms a convex surface and the sealant layer 4 forms a concave surface. The following methods can be used to shape the recessed area. • Heated pressure air molding method: A method in which battery packaging material is sandwiched between a lower mold having holes for supplying high-temperature, high-pressure air and an upper mold having a pocket-shaped recess, and the recess is formed by supplying air while heating and softening the material. • Preheater flat plate compressed air molding method: A method in which battery packaging material is heated and softened, then sandwiched between a lower mold having holes for supplying high-pressure air and an upper mold having pocket-shaped recesses, and the recesses are formed by supplying air. • Drum-type vacuum forming method: A method in which battery packaging material is partially heated and softened in a heated drum, and then the recesses of a drum having pocket-shaped recesses are vacuumed to form the recesses. • Pin molding method: A method in which the bottom material sheet is heated and softened, and then pressed into place using a mold with pocket-shaped indentations and recesses. • Preheater plug-assisted compressed air molding method: A method in which battery packaging material is heated and softened, then sandwiched between a lower mold having holes for supplying high-pressure air and an upper mold having a pocket-shaped recess, and the recess is formed by supplying air, and a convex-shaped plug is raised and lowered during molding to assist the molding process.

[0132] In particular, the preheater plug-assisted compressed air molding method, which is a heated vacuum molding method, is preferred because it allows for a uniform thickness of the bottom material after molding.

[0133] (Uses of battery packaging materials) The battery packaging material of the present invention is used as a battery container for sealing and housing battery elements such as a positive electrode, a negative electrode, and an electrolyte.

[0134] Specifically, a battery is provided using the battery packaging material of the present invention, which covers a battery element comprising at least a positive electrode, a negative electrode, and an electrolyte, with the metal terminals connected to the positive and negative electrodes respectively protruding outward, such that a flange portion (an area where sealant layers come into contact) is formed around the periphery of the battery element, and then heat-seals the sealant layers of the flange portion to seal it. When housing a battery element using the battery packaging material of the present invention, the sealant portion of the battery packaging material of the present invention is used so that it faces inward (the surface in contact with the battery element).

[0135] The battery packaging material of the present invention may be used for either primary or secondary batteries, but is preferably used for secondary batteries. The type of secondary battery to which the battery packaging material of the present invention is applied is not particularly limited, and examples include lithium-ion batteries, lithium-ion polymer batteries, solid-state batteries, lead-acid batteries, nickel-metal hydride batteries, nickel-cadmium batteries, nickel-iron batteries, nickel-zinc batteries, silver oxide-zinc batteries, metal-air batteries, polyvalent cation batteries, capacitors, and the like. Among these secondary batteries, lithium-ion batteries, lithium-ion polymer batteries, and solid-state batteries are particularly suitable applications for the battery packaging material of the present invention. [Examples]

[0136] The present invention will be described in more detail below with reference to specific synthesis examples and embodiments, but the present invention is not limited to these embodiments. In the following examples, "parts" and "%" represent "parts by mass" and "mass%", respectively, unless otherwise specified.

[0137] <Polyol composition (A)> (Synthesis Example 1) Synthesis of polyester polyol (A1-1) A polyester polyol was synthesized according to a standard method using 790.8 parts isophthalic acid, 339.4 parts terephthalic acid, 20.0 parts trimellitic anhydride, 738.0 parts 1,6-hexanediol, and 107.4 parts neopentyl glycol in a 2-liter four-necked glass flask equipped with a stirring blade, temperature sensor, nitrogen gas inlet tube, and rectification column. The obtained polyester polyol was diluted with ethyl acetate to a resin solid content of 58% to obtain polyester polyol (A1-1) with a number average molecular weight (Mn) of 7,900, a weight average molecular weight (Mw) of 25,700, a resin hydroxyl value (based on solid content) of 22.2 mg KOH / g, a resin acid value (based on solid content) of 0.82 mg KOH / g, and a glass transition temperature (Tg) of 7.3°C.

[0138] (Synthesis Example 2) Synthesis of polyester polyol (A1-2) A polyester polyol was prepared by using 697.2 parts terephthalic acid, 72.9 parts ethylene glycol, and 229.9 parts 1,2-propylene glycol in a 2-liter four-necked glass flask equipped with a stirring blade, temperature sensor, nitrogen gas inlet tube, and rectification column, according to a standard method. The obtained polyester polyol was diluted with methyl ethyl ketone to a resin solid content of 30% to obtain polyester polyol (A1-2) with a number average molecular weight (Mn) of 8,400, a weight average molecular weight (Mw) of 61,300, a resin hydroxyl value (based on solid content) of 5.0 mg KOH / g, a resin acid value (based on solid content) of 4.0 mg KOH / g, and a glass transition temperature of 84°C.

[0139] (Synthesis Example 3) Synthesis of polyester polyols (A1-3) A polyester polyol was synthesized according to a standard method using 300.3 parts isophthalic acid, 300.3 parts terephthalic acid, 37.7 parts neopentyl glycol, 101.0 parts ethylene glycol, and 260.7 parts 1,9-nonanediol in a 2-liter four-necked glass flask equipped with a stirring blade, temperature sensor, nitrogen gas inlet tube, and rectification column. The obtained polyester polyol was diluted with methyl ethyl ketone to a resin solid content of 60% to obtain polyester polyol (A1-3) with a number average molecular weight (Mn) of 3,000, a weight average molecular weight (Mw) of 16,000, a resin hydroxyl value (based on solid content) of 19.2 mg KOH / g, a resin acid value (based on solid content) of 0.55 mg KOH / g, and a glass transition temperature (Tg) of 10.7°C.

[0140] The physical properties of the polyester polyol were measured as follows. (Molecular weight measurement method) Measuring device: HLC-8320GPC, manufactured by Tosoh Corporation. Columns; manufactured by Tosoh Corporation: TSKgel 4000HXL, TSKgel 3000HXL, TSKgel 2000HXL, TSKgel 1000HXL Detector; RI (Differential Refractometer) Data processing; Tosoh Corporation Multi-Station GPC-8020 model II Measurement conditions: Column temperature 40°C Solvent: tetrahydrofuran Flow rate 0.35ml / min Standard; monodisperse polystyrene Sample: 100 μl of a tetrahydrofuran solution containing 0.2% by mass (based on resin solids content) filtered through a microfilter.

[0141] (Acid value measurement method) 5.0 g of the sample was accurately weighed, dissolved in 30 mL of neutral solvent, and titrated with a 0.1 mol / L potassium hydroxide solution (methanol-based). Phenolphthalein was used as an indicator. The measurement results were converted to the amount of potassium hydroxide required to neutralize 1 g of the sample, and the unit was mgKOH / g.

[0142] (Hydroxyl value measurement method) 4.0 g of the sample (based on solid content) was accurately weighed, and 25 mL of an acetylating agent consisting of anhydrous acetic acid / pyridine (volume ratio 1 / 19) was added. The mixture was sealed and heated at 100°C for 1 hour. After acetylation, 10 mL of deionized water and 100 mL of tetrahydrofuran were added, and the mixture was titrated with a 0.5 mol / L potassium hydroxide solution (alcoholic). Phenolphthalein was used as an indicator. The measurement results were converted to the amount of potassium hydroxide required to neutralize the acetic acid produced when 1 g of the sample was acetylated, and the unit was mgKOH / g.

[0143] (Method for measuring glass transition temperature) A 5 mg sample was heated using DSC from room temperature to 200°C at a rate of 10°C / min under a nitrogen flow of 30 mL / min, then cooled to -80°C at a rate of 10°C / min, and then heated again to 150°C at a rate of 10°C / min. The DSC curve was then measured. In the measurement results observed during the second heating process, the glass transition point was defined as the intersection of a straight line extending the low-temperature baseline towards the high-temperature side and a tangent line drawn at the point where the slope of the curve representing the step-like portion of the glass transition is maximum. The temperature at this point was defined as the glass transition temperature.

[0144] <Polyisocyanate composition (B)> (Synthesis Example 4) Synthesis of urethane prepolymer (B1-1) In a flask equipped with a stirrer, thermometer, and nitrogen gas inlet tube, 40.2 parts of 4,4-diphenylmethane diisocyanate (hereinafter abbreviated as "4,4'-MDI") and 10.0 parts of hexamethylene diisocyanate nurate (hereinafter abbreviated as "HDI nurate") were charged into the reaction vessel and stirred under nitrogen gas, and heated to 60°C. To this flask, 37.8 parts of bifunctional polypropylene glycol with a number average molecular weight of 1000 (hereinafter abbreviated as "PPG1000") and 2.0 parts of 2,2,4-trimethyl-1,3-pentanediol (hereinafter abbreviated as "TMPD") were added dropwise in several batches, and the mixture was stirred at 80°C for 5 to 6 hours to carry out the urethane reaction, thereby obtaining urethane prepolymer (B1-1).

[0145] (Synthesis Example 5)~(Synthesis Example 7) Synthesis of urethane prepolymers (B1-2)~(B1-4) Urethane prepolymers (B1-2) to (B1-4) were obtained in the same manner as urethane prepolymer (B1-1), except that the polyol (b1-1) and polyisocyanate (b1-2) used and their amounts were changed as shown in Table 1. In the table, PPG400 is polypropylene glycol with a number average molecular weight of 400, PPG700 is polypropylene with a number average molecular weight of several hundred, and PTMG650 is polytetramethylene ether glycol with a number average molecular weight of 650.

[0146] (Synthesis Example 8) Synthesis of urethane prepolymer (BH1) A 2-liter four-necked glass flask equipped with a stirring blade, temperature sensor, nitrogen gas inlet tube, and rectification column was charged with 12.2 parts ethylene glycol, 27.4 parts neopentyl glycol, 51.5 parts adipic acid, and 8.9 parts isophthalic acid. The mixture was gradually heated under atmospheric pressure and a nitrogen stream, and the temperature was raised to 220°C while dehydration was carried out. The reaction was continued at 220°C. After confirming that the top temperature of the rectification column was below 80°C, the rectification column was removed and the mixture was switched to a glass condenser. A line was connected from the nitrogen gas inlet tube to a vacuum pump, and the condensation reaction was carried out under reduced pressure of 50 Torr until the desired acid value was reached, thereby obtaining a polyester polyol intermediate for urethane prepolymer (BH). The number-average molecular weight (Mn) of the intermediate polyester polyol was 1,500, the weight-average molecular weight (Mw) was 5,000, the hydroxyl value was 70 mgKOH / g, and the acid value was 1.0 mgKOH / g.

[0147] In a 2-liter four-necked glass flask equipped with a stirrer, thermometer, and nitrogen gas inlet tube, 52.6 parts of a mixture of 2,2'-diphenylmethane diisocyanate, 2,4'-diphenylmethane diisocyanate, and 4,4'-diphenylmethane diisocyanate in a mass ratio of 54:45:1 were charged and heated to 60°C while stirring under a nitrogen gas stream. 47.7 parts of the intermediate polyester polyol synthesized above were added dropwise in several portions, and the mixture was further heated and maintained at an internal temperature of 80°C for 4 hours to carry out the urethane formation reaction, yielding a urethane prepolymer (BH1) with an NCO group content of 15.0% and isocyanate groups at both ends.

[0148] [Table 1]

[0149] <Preparation of adhesive> (Example 1) Polyester polyols (A1-1), (A1-2), and (A1-3) were mixed to obtain the solid content shown in Table 2, and ethyl acetate was added to prepare polyol composition (A) with a solid content concentration of 45%. Similarly, urethane prepolymer (B1-1), TDI-TMP adduct (B2), and polyisocyanate compound (B3-1) were mixed to obtain the solid content shown in Table 2, and ethyl acetate was added to obtain polyisocyanate composition (B) with a non-volatile content of 45%. These were mixed and thoroughly stirred to prepare the adhesive of Example 1.

[0150] (Examples 2) to (Examples 7) Adhesives for Examples 2 to 7 were manufactured in the same manner as in Example 1, except that the materials and formulations used for preparing the adhesive were adjusted to the values ​​shown in Table 2. (Comparative Example 1), (Comparative Example 2) The adhesives of Comparative Example 1 and Comparative Example 2 were manufactured in the same manner as in Example 1, except that the materials and formulations used for preparing the adhesive were adjusted to the values ​​shown in Table 3.

[0151] Details of the compounds in Tables 2 and 3 that are not described above are as follows. (TDI-TMP Adduct Body (B2)) Adduct of toluene diisocyanate and trimethylolpropane (Polyisocyanate compound (B3-1)) Carbodiimide modified form of diphenylmethane diisocyanate (Polyisocyanate compound (B3-2)) MDI50 (a mixture of 2,2'-diphenylmethane diisocyanate, 2,4'-diphenylmethane diisocyanate, and 4,4'-diphenylmethane diisocyanate in a mass ratio of 54:45:1)

[0152] <Manufacturing of battery packaging materials: Composition shown in Figure 2> (Example 1) As the metal layer 3, a 40 μm thick aluminum foil mat surface was coated with the adhesive from Example 1 as the adhesive layer 2 at a rate of 3 g / m² using a dry laminator. After the solvent evaporated, a 25 μm thick stretched polyamide film was laminated as the outer layer substrate layer 1. Next, the adhesive for the bonding layer 5 was applied to the glossy aluminum foil surface of the metal layer 3 of the obtained laminated film using a dry laminator at an application rate of 3 g / m². After the solvent evaporated, an unstretched polypropylene film with a thickness of 40 μm was laminated as the sealant layer 4. Then, curing (aging) was performed at 60°C for 5 days to cure the adhesive and obtain a laminated product.

[0153] (Examples 2) to (Examples 7) In the same manner as in Example 1, the adhesives of Examples 2 to 7 were used as the adhesive layer 2 to obtain the battery packaging materials of Examples 2 to 7.

[0154] (Comparative Example 1), (Comparative Example 2) In the same manner as in Example 1, the adhesives of Comparative Examples 1 and 2 were used as the adhesive layer 2 to obtain the battery packaging materials of Comparative Examples 1 and 2.

[0155] The evaluation of battery packaging materials was carried out as follows. <Adhesive strength> Using Shimadzu Corporation's "Autograph AGS-J," the adhesive strength of the interface between the outer substrate layer 1 and the metal layer 3 of the battery packaging material in the examples or comparative examples was evaluated under the conditions of a peeling speed of 50 mm / min, a peeling width of 15 mm, and a peeling pattern of 180°. A higher numerical value indicates a more suitable adhesive.

[0156] <Hot Strength> Using the "Tensile Testing Machine Constant Temperature Chamber TLF-R2-S" manufactured by Orientec Co., Ltd. and the "RTG-1210" manufactured by A&D Co., Ltd., the adhesive strength of the interface between the outer substrate layer 1 and the metal layer 3 of the battery packaging material in the examples or comparative examples was evaluated under the conditions of a 120°C atmosphere, a peeling speed of 50 mm / min, a peeling width of 15 mm, and a peeling mode of free peeling. A higher numerical value indicates a more suitable adhesive.

[0157] <Moldability> Using Yamaoka Seisakusho Co., Ltd.'s "1-ton Tabletop Servo Press (SBN-1000)," the battery packaging material for the example or comparative example was cut to a size of 60 x 60 mm to serve as a blank (workpiece, material). With the aluminum foil mat surface facing the convex side of the blank, it was molded with a molding height of 4.0 mm using a straight die with a free molding height. The punch shape of the die used was a 30 mm square with a corner radius of 2 mm and a punch shoulder radius of 1 mm. The die hole shape of the die used was a 34 mm square with a die hole corner radius of 2 mm and a die hole shoulder radius of 1 mm. The clearance between the punch and the die hole was 0.3 mm on each side. The presence or absence of aluminum foil breakage and lifting between each layer was checked at 20 locations near the boundary between the flange and the side wall, and the following evaluation was performed in three stages. ○: Less than 10% of the areas showed fracture or lifting. △: Breakage or lifting was observed in 10% to less than 20% of the area. ×: More than 20% of the area showed signs of fracture or lifting.

[0158] <Heat seal resistance> Using Yamaoka Seisakusho Co., Ltd.'s "1-ton Tabletop Servo Press (SBN-1000)", the laminate of the example or comparative example was cut to a size of 60 x 60 mm, and stretch molding was performed with a molding height of 4.0 mm using a straight mold with a molding height of free, with the aluminum foil mat surface facing outwards. A heat sealing bar was applied to the flange portion of the obtained 30 mm square tray at 180°C for 6 seconds, in contact with the side wall. The presence or absence of lifting between the stretched polyamide film and the aluminum foil was checked at 12 locations near the boundary between the flange portion and the side wall portion, and evaluated in the following three stages. ○: Less than 20% of the areas showed signs of fracture or lifting. △: Breakage or lifting was observed in 20% to less than 50% of the area. ×: More than 50% of the areas showed signs of fracture or lifting.

[0159] <Boiling resistance> Using Yamaoka Seisakusho Co., Ltd.'s "1-ton Tabletop Servo Press (SBN-1000)", the laminate of the example or comparative example was cut to a size of 60 x 60 mm, and with the aluminum foil mat surface facing outwards, it was stretch-molded at a molding height of 4.0 mm using a straight die with a free molding height. The resulting 30 mm square tray was placed in a constant temperature and humidity chamber at 60°C while submerged in water and left to stand for one week. After removing the tray from the constant temperature and humidity chamber, the presence or absence of floating between the stretched polyamide film and the aluminum foil at eight locations near the boundary between the flange and the side wall was checked and evaluated in the following three stages. ○: Less than 20% of the areas showed signs of fracture or lifting. △: Breakage or lifting was observed in 20% to less than 50% of the area. ×: More than 50% of the areas showed signs of fracture or lifting. [Table 2]

[0160] [Table 3]

[0161] These results clearly demonstrate that by using the adhesive of the present invention, it is possible to obtain a battery packaging material that has excellent moldability and heat resistance, and that does not experience a decrease in interlayer adhesive strength even after heat fusion of sealant layers to encapsulate battery elements, and even after long-term durability testing under high temperature and high humidity conditions, thereby suppressing appearance defects such as lifting between layers. [Explanation of Symbols]

[0162] 1: Outer layer side base material layer 2: Adhesive layer 3: Metal layer 4: Sealant layer 5: Adhesive layer

Claims

1. The present invention comprises a polyol composition (A) and a polyisocyanate composition (B), The polyol composition (A) is a reaction product of a polyhydric carboxylic acid and a polyhydric alcohol, and comprises a polyester polyol (A1) in which 30 mol% or more of the polyhydric carboxylic acid is an aromatic polyhydric carboxylic acid. The polyisocyanate composition (B) comprises a urethane prepolymer (B1) which is a reaction product of a polyol (b1-1) containing a polyether polyol and a polyisocyanate (b1-2), and a trimethylolpropane adduct (B2) of toluene diisocyanate. The proportion of the toluene diisocyanate trimethylolpropane adduct (B2) in the solid content of the polyisocyanate composition (B) is 10% by mass or more and 85% by mass or less. A two-component curing adhesive wherein the polyisocyanate (b1-2) contains a nurate-type polyisocyanate compound, and the content of the nurate-type polyisocyanate compound in the polyisocyanate (b1-2) is 5% by mass or more and 50% by mass or less.

2. The two-component curing adhesive according to claim 1, wherein the polyisocyanate (b1-2) comprises an aromatic polyisocyanate, and the content of the aromatic polyisocyanate in the polyisocyanate (b1-2) is 50% by mass or more and 95% by mass or less.

3. The two-component curing adhesive according to claim 1, wherein the molar ratio of isocyanate groups contained in the polyisocyanate composition (B) to active hydrogen groups contained in the polyol composition (A) is 1.5 or more and 15 or less.

4. The polyester polyol (A1) comprises polyester polyol (A1-1) and polyester polyol (A1-2). The glass transition temperature of the polyester polyol (A1-1) is -30°C or higher and 20°C or lower. The two-component curing adhesive according to claim 1, wherein the glass transition temperature of the polyester polyol (A1-2) is 50°C or higher and 110°C or lower.

5. A laminate comprising a first substrate, a second substrate, and an adhesive layer for bonding the first substrate and the second substrate, wherein the adhesive layer is a cured coating film of a two-component curing adhesive as described in any one of claims 1 to 4.

6. A laminate for battery casing material, comprising a first substrate, a second substrate, and an adhesive layer for bonding the first substrate and the second substrate, wherein the adhesive layer is a cured coating film of a two-component curing adhesive as described in any one of claims 1 to 4.

7. A battery packaging material obtained by molding the laminate described in claim 6.

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