TWI769211B - Adhesive composition, laminate, packaging material for electric storage device, container for electric storage device and electric storage device - Google Patents

Abstract

To provide an adhesive composition, a packaging material for an electric storage element, a container for an electric storage element, and an electric storage element which can maintain a high adhesive strength without causing appearance defects in the molded part. The adhesive composition contains a polyolefin resin component and a hardener, the polyolefin resin component contains a polyolefin resin, has a carboxyl group or an acid anhydride group, has a melting point of 55°C to 100°C, and a weight average molecular weight of 40,000 to 400,000; and a polymer, It has a carboxyl group or an acid anhydride group, and the weight average molecular weight is 200 to 13000; the content of the polymer relative to the polyolefin resin and the polymer and 100% by weight of the polymer is 0.2% by weight to 5.0% by weight. At least one of an oxy group, a carbodiimide group, and an aziridine group.

Description

Adhesive composition, laminate, packaging material for electrical storage element, container for electrical storage element, and electrical storage element

The present invention relates to an adhesive composition. Moreover, this invention relates to the laminated body which laminated|stacked the metal foil and the thermal fusion resin film using the said adhesive composition, and the packaging material for electrical storage elements. Furthermore, this invention relates to the container for electric storage elements which processed the said packaging material for electric storage elements so that the said thermal fusion resin film may become an inner surface, and the electric storage element using the said container for electric storage elements.

A secondary battery is a typical power storage element. Due to the rapid development of electronic devices such as mobile phones and portable personal computers, the demand for secondary batteries such as light-weight and small lithium-ion batteries is increasing. As the outer body of the secondary battery, metal cans have been used until now, but from the viewpoints of weight reduction and productivity, packaging materials in which plastic films, metal foils, etc. are laminated are becoming mainstream. As the simplest packaging material for electrical storage elements (hereinafter, also referred to as packaging material), an outer layer side resin film ( 11 ), an outer layer side adhesive layer ( 12 ), and a metal foil are included in this order from the outer layer side as shown in FIG. 1 . (13), a laminate of an inner layer side adhesive layer (14) and a thermal fusion resin film (15). As shown in FIG. 2 , the battery container is formed by molding the packaging material (deep-drawing molding, drawing molding, etc. ) is made. Then, an electrode, an electrolyte solution, etc. are enclosed in the concave surface side of the container for a battery, and a battery is manufactured by sealing. In addition, capacitors (capacitors) are also one of power storage elements, and among them, lithium-ion capacitors are expected to grow in the market in the future.

In the packaging material for electrical storage elements, the following performances are mainly required for the inner layer side adhesive layer for bonding the metal foil and the thermal fusion resin film together. (1) The bonding strength between the metal foil and the thermal fusion resin film is high. (2) The adhesive layer on the inner layer side has electrolyte solution resistance. That is, even when the electrolyte is sealed in the battery container, the adhesive strength between the metal foil and the thermal fusion resin film can be maintained. For example, the electrolyte solution of the lithium battery includes a lithium salt (electrolyte) such as lithium hexafluorophosphate and a solvent such as propylene carbonate (propylene carbonate), ethylene carbonate (ethylene carbonate), diethyl carbonate, and dimethyl carbonate. When the electrolyte solution put in the container for storage elements passes through the thermal fusion resin film and reaches the adhesive layer, the adhesive strength between the thermal fusion resin film and the metal foil is lowered. In addition, when moisture penetrates into the electrolyte solution from the outside of the battery container, a lithium salt such as lithium hexafluorophosphate reacts with water to generate hydrofluoric acid. The generated hydrofluoric acid becomes a factor for deteriorating the thermal fusion resin film and the adhesive layer, and when the metal foil passes through the thermal fusion resin film and the adhesive layer and reaches the metal foil, the metal foil corrodes. When metal corrosion occurs, the adhesive strength between the thermal fusion resin film and the metal foil is significantly reduced. Therefore, the inner layer side adhesive layer in which the thermal fusion resin film and the metal foil are bonded together is required not only to be resistant to the electrolyte itself, but also to be resistant to substances generated by ingress from the outside of the storage element acting on the electrolyte. tolerance.

In order to achieve the performance required as an adhesive on the inner layer side, Patent Document 1 (Japanese Patent Laid-Open No. 2003-123708 ) discloses an adhesive containing an acid-modified thermoplastic elastomer (A) and a coupling agent (B). combination. Also disclosed is a secondary battery using a laminate as a packaging material in which the adhesive composition is used for bonding an unstretched polypropylene film and an aluminum foil formed by laminating a nylon film, and comprising: Unstretched polypropylene film/adhesive layer/aluminum foil/nylon film. Furthermore, it is also disclosed that an adhesion imparting agent may be contained in the adhesive composition.

Patent Document 2 (WO2004/041954) discloses an adhesive composition comprising a carboxyl group-containing thermoplastic elastomer (A), a polyolefin polyol (B), an adhesion imparting agent (C) and a polyfunctional isocyanate (D) ). Furthermore, there is disclosed a laminate obtained by bonding an aluminum foil or a polyethylene terephthalate film to an unstretched polypropylene film using the adhesive. In addition, Patent Document 3 (Japanese Unexamined Patent Application Publication No. 2005-063685 ) discloses an adhesive containing a polyolefin polyol and a polyfunctional isocyanate hardener as essential components, and describes a packaging material for a battery case, which uses In this adhesive agent, an aluminum foil and a thermoplastic resin film are bonded together, and the thermoplastic resin film is used as an inner layer.

Patent Document 4 (WO2009/087776) discloses an adhesive composition having a polyolefin resin having a carboxyl group and a polyfunctional isocyanate having a melting energy of 5 mJ/mg to 15 mJ/mg. In addition, Patent Document 5 (Japanese Unexamined Patent Application Publication No. 2010-092703 ) discloses an adhesive comprising a polyolefin resin having a carboxyl group and a polyfunctional isocyanate compound, and describes the gist that it can be used as a An aluminum foil and a thermoplastic resin film are bonded together with the adhesive, and the thermoplastic resin film is used as a packaging material for a battery case of an inner layer.

[Problem to be Solved by the Invention] With the expansion of applications in vehicle-mounted or home power storage, etc., the power storage element is required to have a larger capacity, long-term durability, and safety. Especially in automotive applications, it is required to maintain excellent adhesion and durability even under conditions of exposure to an electrolyte solution. In particular, in the molded packaging material, the film or the adhesive is stretched during molding, and therefore higher-level durability such as no floating when immersed in an electrolyte solution is required.

The adhesives described in Patent Documents 1 to 3 exhibit sufficient adhesive strength, but there is a problem that the crosslinked structure of the adhesive deteriorates due to long-term immersion in an electrolytic solution, and sufficient adhesive strength cannot be maintained. In addition, compared with Patent Documents 1 to 3, the adhesives described in Patent Documents 4 and 5 improve the durability of the cross-linked structure, so that the long-term electrolyte solution resistance is improved, but it is still insufficient. In particular, when the packaging material is molded, there is a problem that appearance defects or floating of the molded portion occur due to immersion in the electrolyte solution for a long time.

The present invention has been made in view of the above-mentioned background, and an object of the present invention is to provide an adhesive which can form a laminate that can maintain a high level of adhesive strength without causing poor appearance in the molded part even if it is immersed in an electrolyte solution for a long time. combination. Moreover, the subject of this invention is to provide the packaging material for electrical storage elements, the container for electrical storage elements, and the electrical storage element which are more excellent in electrolyte solution resistance than before. [Technical means to solve the problem]

The inventors of the present invention, as a result of repeated studies, found that the problems of the present invention can be solved by the following embodiments, and completed the present invention. [1]: An adhesive composition comprising a polyolefin resin component and a curing agent (C), wherein the polyolefin resin component includes a polyolefin resin (A), having a carboxyl group or an acid anhydride group, and having a melting point of 55 ℃～100℃, the weight-average molecular weight is 40,000-400,000; and the polymer (B) has a carboxyl group or an acid anhydride group, and the weight-average molecular weight is 200-13,000; in the polyolefin resin (A) and the polymer (B) ) contains 0.2 to 5.0 wt % of the polymer (B) in a total of 100 wt %, and the curing agent (C) has an isocyanate group, an epoxy group, a carbodiimide group, and an aziridine group selected from the group consisting of At least one functional group in the group consisting of radicals.

[2]: The adhesive composition according to [1], wherein the acid value X (mmol/g) of the polymer (B) is 1.2 to 20. [3]: The adhesive composition according to [1] or [2], wherein the acid value P (mmol/g) of the polyolefin resin (A) is 0.02 to 1.2. [4]: The adhesive composition according to any one of [1] to [3], wherein the polyolefin resin (A) is i(g), the polymer is When (B) is set to j(g) and the functional group of the hardening agent is set to Z (mmol), Z/(P*i+X*j) is 0.3 to 10.

[5]: The adhesive composition according to any one of [1] to [4], wherein the polymer (B) is a homopolymer (b- 1), or an unsaturated carboxylic acid or its anhydride, and at least one polymer (b-2) selected from the group consisting of aromatic vinyl compounds, aliphatic α-olefin compounds, and conjugated diene compounds . [6]: The adhesive composition according to any one of [1] to [5], wherein the polyolefin resin (A) has a melting point of 65°C to 90°C and a weight average molecular weight of 100,000 to 300,000.

[7]: A laminate characterized by having an adhesive layer between a metal foil and a heat-sealing resin film layer, the adhesive layer being made of any one of [1] to [6] Then a dosage composition is formed. [8]: The laminate according to [7], wherein a surface-treated layer is provided between the metal foil and the adhesive layer, and the surface-treated layer is treated with a curing agent (C). The reactant is formed. [9]: The laminate according to [8], wherein the treatment agent contains at least one selected from the group consisting of a carboxyl group, a hydroxyl group, and an amino group.

[10]: A packaging material for an electric storage element, which requires an outer layer side resin film, an outer layer side adhesive layer, a metal foil, an inner layer side adhesive layer, and a thermal fusion resin film in this order from the outside, the electric storage element packaging material is characterized in that: the inner layer side adhesive layer is formed of the adhesive composition according to any one of [1] to [6].

[11]: A container for an electric storage element formed of the packaging material for an electric storage element according to [10], wherein the inner surface of the container for an electric storage element is formed by a thermally fused resin film. [12]: An electric storage element using the container for an electric storage element according to [11].

ADVANTAGE OF THE INVENTION According to this invention, even if it is immersed in an electrolyte solution for a long time, it does not generate|occur|produce an appearance defect in a molded part, and can provide the adhesive composition which can maintain the adhesive strength of a high level of a laminated body. In addition, the present invention can provide a packaging material for an electric storage element, a container for an electric storage element, and an electric storage element which are more excellent in the electrolyte solution resistance than before.

Hereinafter, embodiments of the present invention will be described in detail. In addition, the description of "arbitrary number A - arbitrary number B" in this specification is an index A and the range larger than number A, and number B and less than number B. As shown in FIG. 1 , the packaging material for an electric storage element of the present embodiment is composed of an outer layer side resin film ( 11 ), an outer layer side adhesive layer ( 12 ), a metal foil ( 13 ), an inner layer side adhesive layer ( 14 ) and The thermal fusion resin film (15) is laminated in sequence. The outer layer side adhesive layer ( 12 ) has a function of laminating (bonding) the outer layer side resin film ( 11 ) and the metal foil ( 13 ). The inner layer side adhesive layer ( 14 ) functions to laminate (bond) the metal foil ( 13 ) and the thermal fusion resin film ( 15 ).

The container for electrical storage elements of this embodiment is formed using the packaging material for electrical storage elements of this embodiment, and its form is not particularly limited. As a preferable example, the container for electric storage elements in the shape of a tray as shown in FIG. 2 is mentioned. In the example of FIG. 2 , a heat-sealing resin film ( 15 ) is arranged inside the tray, that is, on the concave surface side forming a space for accommodating electrodes, electrolyte solutions, etc., and an outer layer side resin film is arranged outside the tray, that is, on the convex surface side. (11). In addition to the tray shape, a cylindrical (cylindrical, square, elliptical, etc.) container for an electrical storage element is also preferable. These containers for electrical storage elements are usually obtained by molding a packaging material for electrical storage elements in a flat state. The inner side of the container for an electric storage element, that is, the surface in contact with the electrolyte solution or the like is a thermal fusion resin film ( 15 ). A flange portion of a thermally fused resin film (15), a flange portion of a thermally fused resin film (15) constituting a packaging material for other electrical storage elements, or a thermally fused resin film (15) of a container for other electrical storage elements The flange portions of the heat-sealing resin films ( 15 ) face each other, are in contact with each other, and are heated, so that the heat-sealing resin films ( 15 ) are welded to each other, and an electrolytic solution or an electric storage element member such as an electrode is encapsulated. In addition to the tray shape, the container for an electrical storage element according to the present embodiment also includes a bag-shaped container (pouch type).

In the container for electric storage element, the metal foil (13) is usually used as a boundary, and the side close to the electrolyte solution is referred to as the "inner layer" and the "inner layer", and the side away from the electrolyte solution is referred to as the "outer layer" and "outer layer". . Therefore, in the intended packaging material for electrical storage elements forming the container for electrical storage elements, the predetermined side close to the electrolyte solution is also referred to as "inner side" and "inner layer" with the metal foil ( 13 ) as a boundary, and is far from the electrolyte. The predetermined side of the solution is referred to as the "outside", "outer layer".

The adhesive composition of the present embodiment can be preferably used for forming the inner layer side adhesive layer ( 14 ). In a state where the adhesive composition of the present embodiment is sandwiched between the metal foil ( 13 ) and the heat-sealing resin film ( 15 ), the carboxyl group or acid anhydride group in the polyolefin resin (A) and the polymer (B) ) in the carboxyl group or acid anhydride group, and the functional group in the hardener (C) reactive with these carboxyl group or acid anhydride group react, whereby a fine and strong cross-linked structure can be formed. As a result, sufficient adhesive strength can be expressed, and the adhesive strength can be maintained at a high level even when immersed in a high-temperature electrolyte solution for a long period of time.

<Polyolefin resin component> The polyolefin resin component includes: a polyolefin resin (A) having a carboxyl group or an acid anhydride group, a melting point of 55°C to 100°C, and a weight average molecular weight of 40,000 to 400,000; and a polymer (B), It has a carboxyl group or an acid anhydride group, and the weight average molecular weight is 200-13,000. The content of the polymer (B) relative to 100% by weight of the polyolefin resin (A) and the polymer (B) is set to be 0.2% by weight to 5.0% by weight.

<Polyolefin resin (A)> The polyolefin resin (A) is preferably a polyolefin resin (A) in view of the solubility in the solvent used for the adhesive composition and the storage stability of the dissolved solution thereof (stable storage without precipitation) Has an amorphous part. On the other hand, in order to improve the electrolyte solution resistance of the adhesive layer in the laminate, it is preferable to also have a crystalline site, and the balance between the amorphous site and the crystalline site is important. The polyolefin resin (A) used in the present embodiment has a weight average molecular weight of 40,000 to 400,000, and a melting point of 55°C to 100°C.

The weight-average molecular weight of the polyolefin resin (A) is 40,000 to 400,000, so that the storage stability of the solution of the polyolefin resin (A) constituting the adhesive composition and the electrolyte solution resistance of the packaging material for electrical storage elements can be easily achieved. properties, heat sealing properties, and coating properties. More preferably, Mw of the polyolefin resin (A) is 100,000 to 400,000, and still more preferably 100,000 to 300,000. In other words, when the Mw of the polyolefin resin (A) is less than 40,000, the crosslinking of the polymer chains of the polyolefin resin (A) may be insufficient, so that the film strength of the adhesive layer may be lowered and the electrolyte solution resistance may be insufficient. Moreover, when Mw exceeds 400,000, the storage stability at 25 degreeC of a polyolefin resin (A) solution may fall, or the viscosity of an adhesive agent solution may become too high, and there exists a possibility that coatability may deteriorate.

The melting point of the polyolefin resin (A) is 55° C. to 100° C., whereby the adhesive strength (initial stage, after immersion in the electrolyte solution) and heat sealability of the battery packaging material can be satisfied in a well-balanced manner. In other words, when the melting point of the polyolefin resin (A) is lower than 55° C., there is a possibility that the adhesive strength or heat sealability after immersion in the electrolyte solution may decrease. When the melting point is higher than 100° C., there is a possibility that the adhesive strength (initial stage, after immersion in an electrolyte solution) may decrease. More preferably, the melting point of the polyolefin resin (A) is 60°C to 90°C, and still more preferably 65°C to 85°C.

In addition, the melting energy (ΔE) of the polyolefin resin (A) is preferably 15 (mJ/mg) to 50 (mJ/mg). Within this range, the adhesive strength and heat sealability after immersion in the electrolyte solution are excellent, and the storage stability of the polyolefin resin (A) solution is also excellent. More preferably, the melting energy (ΔE) of the polyolefin resin (A) is 20 (mJ/mg) to 50 (mJ/mg), and still more preferably 20 (mJ/mg) to 40 (mJ/mg).

The term "having storage stability" in this specification means that 10 g of resin is added to a mixed solvent of 40 g of toluene, 40 g of methylcyclohexane, and 10 g of methyl ethyl ketone, and the resin is heated and dissolved to obtain After the transparent solution, it was left to stand at 4°C for 1 day, and again at 25°C for 1 day. At this time, the fluidity was maintained without any change in appearance such as gelation or precipitation.

Here, the heat sealability will be described. The packaging material for electrical storage elements is also required to be excellent in heat sealability in addition to adhesive strength and electrolyte solution resistance. The heat-sealing resin film ( 15 ) (heat-seal layer) functions to encapsulate an electric storage element member such as an electrolytic solution or an electrode in the container for an electric storage element. Specifically, the heat-sealing resin film ( 15 ) constituting the container for electric storage elements and the heat-sealing resin film ( 15 ) of the same or other container for electric storage elements (packaging material for electric storage elements) are arranged to face each other, and they are heated to each other. By welding, the container for the electric storage element is hermetically sealed. From the viewpoint of securing the heat-sealing strength (peeling strength between the heat-sealing resin films ( 15 )), heat-sealing under high temperature and high pressure is preferable. However, if the adhesive layer (14) for bonding the heat-sealing resin film (15) to the metal foil (13) is melted or deformed due to heat and pressure during heat sealing, there is a possibility that the electrode terminal and the metal foil (13) ) is turned on. When turned on, it does not function as a power storage element. Therefore, it is required that the insulation between the electrode terminal and the metal foil (13) is not damaged by heat sealing, and that the adhesive layer (14) is not melted or deformed by heat and pressure during heat sealing. It is preferable to use a polyolefin resin (A) having a melting point or fusion energy (ΔE) within the above-mentioned range, since it is easy to suppress and prevent melting or deformation of the adhesive layer ( 14 ) during heat sealing.

The polyolefin resin (A) needs to have a carboxyl group or an acid anhydride group, and a strong cross-linked structure is formed by the reaction of the carboxyl group or the acid anhydride group with the curing agent (C) described later, whereby sufficient adhesive strength and electrolyte solution resistance can be exhibited. . From the viewpoint of being excellent in adhesiveness and solubility, the polyolefin resin (A) preferably has an acid value P (mmol/g) of 0.02 to 1.2. Within this range, adhesive strength and durability in an electrolytic solution are excellent due to the cross-linking reaction. In addition, crosslinking shrinkage of the coating film due to excessive crosslinking is less likely to occur, and adhesive strength and solubility in solvents are excellent.

As a method of introducing a carboxyl group or an acid anhydride group, for example, a method of graft-polymerizing an ethylenically unsaturated carboxyl group or an acid anhydride thereof to a polyolefin resin (A1) not having a carboxyl group or an acid anhydride group, or a method of combining an olefin monomer with ethylene A method of copolymerizing an unsaturated carboxylic acid or its anhydride, etc. In addition, a polyolefin having a carboxyl group can also be obtained by reacting an acid anhydride group of a polyolefin having an acid anhydride group with water, an alcohol, or the like. Among them, a modified polyolefin resin obtained by graft-polymerizing an ethylenically unsaturated carboxyl group or an acid anhydride thereof to a polyolefin resin (A1) not having a carboxyl group or an acid anhydride group is preferable. The polyolefin resin (A) may be used alone or in any combination of two or more.

The graft polymerization method of polyolefin is not particularly limited, and for example, the method disclosed in Japanese Patent Laid-Open No. 11-293216 can be used.

As a radical initiator that can be used in the graft polymerization of polyolefin, for example, benzyl peroxide, diisopropyl peroxydicarbonate, di-n-propyl peroxydicarbonate, dicumyl peroxide, Di-tert-butyl peroxide, tert-butyl peroxyneodecanoate, tert-butyl peroxy-2-ethylhexanoate, tert-butyl peroxytrimethyl acetate, 2,5-dimethyl-2,5 - Well-known organic peroxides, such as bis (tert-butyl peroxide) hexane, can select the most preferable organic peroxide according to reaction conditions. These may be used alone or in combination of two or more.

The polyolefin resin (A1) is not particularly limited, and examples thereof include homopolymerization of olefin monomers such as ethylene, propylene, 1-butene, butadiene, isoprene, 1-hexene, and 1-octene. polymers, copolymers of olefin monomers with each other or copolymers with other monomers, and polymers mainly composed of hydrocarbon skeletons, such as hydrides or halides of the obtained polymers. A copolymer of olefin monomers is preferable.

The copolymer of olefin monomers is preferably a copolymer of 1-butene and other olefin monomers. The other olefins are preferably ethylene and propylene, and examples of the copolymers of 1-butene and other olefin monomers include binary copolymers of ethylene and 1-butene, binary copolymers of propylene and 1-butene, ethylene A terpolymer with propylene and 1-butene, more preferably a binary copolymer of propylene and 1-butene. The copolymerization ratio is preferably propylene:1-butene=10:90 to 90:10 (mol ratio), and more preferably 40:60 to 80:20 (mol ratio). In the copolymer of propylene and 1-butene, the melting point may be lower than 55°C when propylene is less than 10 mol%, and the melting point may be higher than 100°C when propylene is more than 90 mol%.

The other monomers that can be copolymerized with the olefin monomer are not particularly limited, and examples thereof include aromatic vinyl compounds such as styrene, α-methylstyrene, and indene; methyl (meth)acrylate and (meth)acrylic acid. ethyl ester, butyl (meth)acrylate, hexyl (meth)acrylate, octyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, dodecyl (meth)acrylate, Alkyl (meth)acrylate compounds such as stearyl (meth)acrylate and behenyl (meth)acrylate; cyclohexyl (meth)acrylate, isobornyl (meth)acrylate, etc. have alicyclic structures (meth)acrylate compounds; (meth)acrylate compounds with aromatic rings such as benzyl (meth)acrylate; 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate , 4-hydroxybutyl (meth)acrylate and other hydroxyl-containing (meth)acrylate compounds; (meth)acrylate dimethylaminoethyl, (meth)acrylate diethylaminoethyl, (methyl) ) (meth)acrylate compounds with amino groups such as tert-butylaminoethyl acrylate; (meth)acrylamide, dimethyl (meth)acrylamide, dimethylaminopropyl (meth)propylene Acrylic amides such as amide, isopropyl (meth) acrylamide, diethyl (meth) acrylamide, hydroxyethyl (meth) acrylamide; (meth)acrylonitrile, acrylamide Morpholine, etc. In terms of graft polymerizability and compatibility with polyolefins, styrene, dodecyl (meth)acrylate, and stearyl (meth)acrylate are preferred. The ethylenically unsaturated carboxylic acid is not particularly limited, and examples thereof include acrylic acid, methacrylic acid, maleic acid, fumaric acid, crotonic acid, itaconic acid, and the like. Only one kind of these ethylenically unsaturated carboxylic acids or their acid anhydrides may be used, or two or more kinds thereof may be used in combination.

The polymerization method of the olefin monomer is not particularly limited. For example, a metal catalyst such as a Ziegler-Natta catalyst or a metallocene catalyst can be added by the method disclosed in Japanese Patent Publication No. 07-080948, or the like. The polymerization is carried out with a catalyst promoter such as (methyl)aluminoxane as needed.

In addition, the weight average molecular weight (Mw) of the polyolefin resin (A) was calculated|required as follows. Using the HLC-8220GPC system manufactured by Tosoh Co., Ltd. obtained by connecting two TSKgel superHZM-N columns, the column temperature was 40°C, the eluent was tetrahydrofuran, and the flow rate was 0.35 mL per minute. measurement below. The sample was prepared by dissolving 2 mg of polyolefin resin (A) in 5 mL of tetrahydrofuran. In addition, Mw was calculated by standard polystyrene conversion. When two or more types of polyolefin resins (A) are used in combination, it means the weight average molecular weight of the whole mixture.

In addition, the melting point and the melting energy (ΔE) can be determined by measuring by differential scanning calorimetry (Differential Scanning Calorimetry, DSC) in accordance with Japanese Industrial Standard (JIS) K7121. Specifically, it is calculated|required as follows. Use the polyolefin resin (A) with a diameter or each side of 0.5 mm or less as it is, and for polyolefin resin (A) exceeding 0.5 mm, cut the polyolefin resin (A) to 0.5 mm or less, and put it in a container Put about 10 mg of polyolefin resin (A). Heating at 10°C per minute to a temperature about 30°C above the melting point, and then cooling at 10°C per minute to a temperature about 50°C lower than Tg. When a clear Tg could not be observed, it was cooled to a temperature lower than the melting point by about 50°C. Then, when heating at 10°C per minute to a temperature approximately 30°C higher than the melting point, the melting point was determined from the peak top of the peak corresponding to melting displayed at that time. In addition, ΔE was obtained from the area of the portion where the peak corresponding to melting was separated from the base line and returned to the base line again. When two or more types of polyolefin resins (A) are used in combination, the melting point is calculated from the peak top of the peak on the high temperature side, and ΔE is calculated from the total of all the peak areas obtained by melting.

<Polymer (B)> The polymer (B) has a carboxyl group or an acid anhydride group, and has a weight average molecular weight of 200 to 13,000. The polymer (B) reacts with the hardener (C) to form a fine cross-linked structure, suppresses the swelling and penetration of the electrolyte solution, and contains only the polyolefin resin component and the hardener (C) that do not contain the polymer (B) Compared with the adhesive layer of , it can dramatically improve the resistance in electrolyte solution.

The polymer (B) can be obtained, for example, by polymerizing a monomer having an unsaturated carboxylic acid or an acid anhydride thereof, or by copolymerizing the monomer and another monomer.

The monomer having an unsaturated carboxylic acid or an anhydride thereof used in the present invention is not particularly limited, and examples having a carboxyl group include acrylic acid, methacrylic acid, maleic acid, fumaric acid, and crotonic acid. , itaconic acid, and unsaturated fatty acids such as oleic acid or linoleic acid. As an example which has an acid anhydride group, maleic anhydride, itaconic anhydride, etc. are mentioned. Only one of these may be used, or two or more of them may be used in combination.

Other monomers that can be copolymerized with unsaturated carboxylic acids or their acid anhydrides are not particularly limited, and examples include: aromatic vinyl compounds such as styrene, α-methylstyrene, and indene; butene and 1-hexene , Aliphatic α-olefin compounds such as 1-octene; Conjugated diene compounds such as butadiene, isoprene, isobutylene; Methyl (meth)acrylate, ethyl (meth)acrylate, (methyl) Butyl acrylate, hexyl (meth)acrylate, octyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, dodecyl (meth)acrylate, stearyl (meth)acrylate Alkyl (meth)acrylate compounds such as behenyl (meth)acrylate; (meth)acrylates having an alicyclic structure such as cyclohexyl (meth)acrylate and isobornyl (meth)acrylate Compounds; (meth)acrylate compounds having aromatic rings such as benzyl (meth)acrylate; 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 4 (meth)acrylate -Hydroxybutyl and other hydroxyl-containing (meth)acrylate compounds; dimethylaminoethyl (meth)acrylate, diethylaminoethyl (meth)acrylate, tert-butylaminoethyl (meth)acrylate (meth)acrylate compounds having amino groups such as esters; (meth)acrylamide, dimethyl (meth)acrylamide, dimethylaminopropyl (meth)acrylamide, isopropyl ( Meth)acrylamide, diethyl (meth)acrylamide, hydroxyethyl (meth)acrylamide and other acrylamides; (meth)acrylonitrile, acrylyl morpholine and the like. Only one of these monomers may be used, or two or more of them may be used in combination.

The polymer (B) is not particularly limited, and may be any of a random polymer, a block polymer, and a graft polymer, and at least a part of the acid anhydride groups in these polymers may be half-esterified or half-amide change. The half-esterified modified product can be obtained by reacting an acid anhydride with a known alcohol using a known half-esterification method. The hemiamidation-modified product can be obtained by reacting an acid anhydride with a known amine using a known hemiamidation reaction method.

In addition, the polymer (B) may be a dimer or trimer of an unsaturated fatty acid, and these are also called dimer acids. In addition, its unsaturated bond can also be hydrogenated. The hydrogenated modified product can be obtained by reacting the unsaturated group of the polymer (B) with hydrogen using a known hydrogenation method.

As a preferable example of a polymer (B), the homopolymer (b-1) of an unsaturated carboxylic acid or its acid anhydride is mentioned. In addition, the polymer (B) is also preferably unsaturated carboxylic acid or its anhydride, and at least one selected from the group consisting of aromatic vinyl compounds, aliphatic α-olefin compounds, and conjugated diene compounds. the polymer (b-2). By using the polymers (b-1) and (b-2), it is difficult to cause poor appearance of the molded part when immersed in the electrolyte solution for a long time. The aliphatic α-olefin compound is preferably an α-olefin having 6 to 30 carbon chains.

As the homopolymer (b-1) of unsaturated carboxylic acid or its anhydride, maleic acid polymer, polyacrylic acid, polymer of unsaturated fatty acid or dimer acid or its hydrogenated product, maleic anhydride polymerized compounds or their half-esters or half-amides, etc.

As the unsaturated carboxylic acid or its anhydride, and at least one polymer (b-2) selected from the group consisting of an aromatic vinyl compound, an aliphatic α-olefin compound, and a conjugated diene compound, there may be mentioned: Maleic anhydride/styrene copolymers, maleic anhydride/α-olefin copolymers, maleic anhydride/isobutylene copolymers, polybutadiene/maleic anhydride graft polymers, or hemiesters or hemiamines of these polymers Amines, etc.

As a radical initiator used when producing a polymer (B) by a radical reaction, a well-known azo type compound and an organic peroxide can be used. As an example of an azo type compound, 2,2'-azobis(isobutyronitrile), 2,2'-azobis-2,4-dimethylvaleronitrile, 2,2'- Azobis(4-methoxy-2,4-dimethylvaleronitrile), 1,1'-azobis-cyclohexane-1-carbonitrile, etc. Examples of the organic peroxide include benzyl peroxide, diisopropyl peroxydicarbonate, di-n-propyl peroxydicarbonate, dicumyl peroxide, di-tert-butyl peroxide, peroxydicarbonate Tert-butyl neodecanoate, tert-butyl 2-ethylhexanoate peroxy, tert-butyl peroxytrimethyl acetate, 2,5-dimethyl-2,5-di(tert-butyl peroxide) Hexane. These may be used alone or in combination of two or more. From the viewpoint of being excellent in reactivity, it is preferable to use an organic peroxide.

The polymer (B) has a weight average molecular weight of 200 to 13,000, has excellent compatibility with the polyolefin resin (A), and can obtain an adhesive excellent in the storage stability of the solution and the curability of the adhesive. More preferably, the polymer (B) having a carboxyl group or an acid anhydride group has a weight average molecular weight of 300 to 10,000. In other words, when the weight average molecular weight of the polymer (B) is less than 200, there is a possibility that the mechanical strength of the adhesive layer becomes low and the resistance to the electrolyte solution is insufficient. On the other hand, when the weight average molecular weight exceeds 13,000, the compatibility with the polyolefin resin (A) may deteriorate, the storage stability of the adhesive solution may deteriorate, or the adhesive film may become white and the adhesive force may deteriorate.

The polymer (B) preferably has an acid value X (mmol/g) of 1.2 to 20 from the viewpoint of obtaining an adhesive excellent in durability in an electrolytic solution. Within this range, durability in an electrolytic solution due to a crosslinking reaction is excellent. In addition, the compatibility with the polyolefin resin (A) is excellent, and then the strength is optimized.

The polymer (B) contains 0.2% by weight to 5% by weight with respect to 100% by weight of the sum of the polyolefin resin (A) and the polymer (B) having a carboxyl group or an acid anhydride group, and an excellent electrolyte solution can be obtained. Durability. More preferably, it is 0.5 to 4 weight%. In other words, when the content of the polymer (B) is less than 0.2 wt %, there is a possibility that the adhesive strength decreases during long-term immersion in the electrolytic solution, or the appearance of the molded part may be defective. In addition, when the content exceeds 5% by weight, the adhesive film may become too hard, and the adhesive force may be deteriorated, or the durability in the electrolyte solution may be deteriorated.

<Other polyolefin resins> In the present embodiment, in addition to the polyolefin resin (A) having a carboxyl group or an acid anhydride group, a polyolefin not having a carboxyl group or an acid anhydride group may be used in combination within a range that does not impair the effects of the invention. The resin is used as the polyolefin resin component. The content of other polyolefin resins is not particularly limited, but is preferably less than 70% by weight, more preferably less than 50% by weight, and still more preferably less than 30% by weight in 100% by weight of the polyolefin resin component.

<Curing agent (C)> Next, the curing agent (C) used in the present invention will be described. The curing agent (C) can exhibit sufficient adhesive strength by reacting with the carboxyl groups or acid anhydride groups of the polyolefin resin (A) and the polymer (B), and can suppress molding even when immersed in an electrolyte solution for a long time. The appearance of the part was poor, and the adhesive strength was maintained at a high level.

The curing agent (C) preferably has at least one functional group selected from the group consisting of an isocyanate group, an epoxy group, a carbodiimide group, and an aziridine group, and more preferably selected from an isocyanate group and an epoxy group. By reacting the functional group with the carboxyl group or acid anhydride group of the polyolefin resin (A) and the polymer (B), a crosslinked structure having high durability in an electrolytic solution can be obtained.

The hardener (C) having an isocyanate group is not limited, and well-known diisocyanates and compounds derived from these can be preferably used. For example, 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, xylylene diisocyanate, diphenylmethane diisocyanate, isophorone diisocyanate, 1,5-naphthalene diisocyanate, Diisocyanates such as methylene diisocyanate, bis(4-isocyanatocyclohexyl)methane, or hydrogenated diphenylmethane diisocyanate, and compounds derived from these diisocyanates. Examples of compounds derived from diisocyanates include isocyanurate compounds, adduct compounds, diurea acetal compounds, uretdione compounds, allophanate compounds, and isocyanate residue-containing compounds of the above-mentioned diisocyanates. prepolymers (oligomers obtained from diisocyanates and polyols), or composites of these. These may be used alone or in any combination of two or more. Among them, the curing agent (C) containing a structure selected from a biuret body, an isocyanurate body, and a urea diketone body is preferable from the viewpoint of excellent durability in an electrolyte solution.

As a commercial item of the hardener (C) having an isocyanate group, for example, Coronate HX, HL, L, and 2770 manufactured by Nippon Polyurethane Co., Ltd., and Polyurethane manufactured by Asahi Kasei Chemical Co., Ltd. Duranate 24A-100, TPA-100, P301-75E, TSE-100, MFA-75B, MHG80-B, Takenate D-110N, D-120N, D-127N, D-160N, D-170N, D-165N, D-178N, etc.

The hardener (C) having an epoxy group is not limited, and a well-known epoxy compound can be preferably used. For example, bisphenol A diglycidyl ether, modified bisphenol A diglycidyl ether, novolak glycidyl ether, glycerol polyglycidyl ether, polyglycerol polyglycidyl ether, N,N-bis(2,3 - Epoxypropyl)aniline, 2-methyl-N,N-bis(2,3-epoxypropyl)aniline, N,N-diglycidylaniline, N,N-diglycidyl -2-methylaniline, N,N,N',N'-tetrakis(2,3-epoxypropyl)-1,4-phenylenediamine, N,N,N',N'-tetrakis(2,3-epoxypropyl)-1,4-phenylenediamine Epoxy compounds having aromatic amino groups such as oxiran-2-ylmethyl)-4,4'-methylenedianiline, N,N-diglycidyl-4-(glycidyloxy)aniline , 2,4,6-tris(glycidyloxy)-1,3,5-triazine and other epoxy compounds having a triazine skeleton, etc. These may be used alone or in any combination of two or more.

As a commercial item of the hardener (C) which has an epoxy group, for example, the Mitsubishi Chemical Corporation make jER-828, jER-834, jER-1001, jER-1002, jER-1004, jER-604 are mentioned. , jER-630, Adeka resin EP-4100, EP-4340, EP-4901, EP-4950, EP-4000, EP-4005, EP- 3950S, EP-3980S, Denacol EX-611, EX614, EX-411, EX-211, R-45EPT manufactured by Nagase ChemteX Co., Ltd., manufactured by Nissan Chemical Co., Ltd. TEPIC-G, TEPIC-S, TEPIC-SP, TEPIC-SS, TEPIC-HP, TEPIC-L, TEPIC-PAS, TEPIC-VL, TETRAD-X, special Rad (TETRAD)-C et al.

The hardener (C) having a carbodiimide group is not limited, but a well-known carbodiimide compound can be preferably used. For example, the well-known diisocyanate and the polycondensate of a derivative|guide_body exemplified in the hardener which have an isocyanate group are mentioned. These may be used alone or in any combination of two or more.

As a commercial item of the hardener (C) which has a carbodiimide group, for example, Nisshinbo Chemical Co., Ltd. Carbodilite V-01, V-03, V-05, V- 07, V-09, etc.

The hardener (C) having an aziridine group is not limited, but a well-known aziridine compound can be preferably used. For example, N,N'-hexamethylene-1,6-bis(1-aziridinecarboxyamide), N,N'-diphenylmethane-4,4'-bis(1-nitrogen) Propylene carboxyamide), trimethylolpropane-tri-beta-aziridinyl propionate, N,N'-toluene-2,4-bis(1-aziridinecarboxyamide), triethylene melamine, trimethylolpropane-tris-beta-(2-methylaziridine) propionate, bisisophthaloyl-1,2-methylaziridine, tris(1-nitrogen) propidyl) phosphine oxide, tris(2-methyl-1-aziridinyl) phosphine oxide, and the like. These may be used alone or in any combination of two or more.

As a commercial item of the hardener (C) which has an aziridine group, for example, Chemitite PZ-33 manufactured by Nippon Catalyst Co., Ltd., and Kurauslinco manufactured by Mutual Pharmaceutical Co., Ltd. (CROSSLINKER) CL-427 et al.

Let the polyolefin resin (A) contained in the adhesive composition be i g (g), the polymer (B) having a carboxyl group or an acid anhydride group be j g (g), and the curing agent (C) When the functional group is set to Z mmol (mmol), Z/(P*i+X*j) (P: acid value of polyolefin resin (A), X: acid value of polymer (B) valence) in the range of 0.3 to 10 to contain the curing agent (C), more preferably in the range of 0.5 to 7. In addition, in this specification, "*" represents a multiplication symbol. If it is in the range of 0.3 to 10, the amount of the epoxy group with respect to the active hydrogen derived from the carboxyl group in the polyolefin resin (A) is suitable, so that the cohesion force, the adhesive strength, and the adhesion in the electrolyte solution are improved by the cross-linked structure. Excellent durability. In addition, unreacted hardener (C) is difficult to exist in excess, so durability in an electrolytic solution is also optimized.

The adhesive of this embodiment may further contain a silane coupling agent. Examples of the silane coupling agent include trialkoxysilanes having a vinyl group such as vinyltrimethoxysilane and vinyltriethoxysilane, 3-aminopropyltriethoxysilane, N-(2- Aminoethyl) 3-aminopropyltrimethoxysilane and other trialkoxysilanes having amino groups, 3-glycidoxypropyltrimethoxysilane, 2-(3,4-epoxycyclohexyl)ethyl Trimethoxysilane having a glycidyl group, such as glycidyl trimethoxysilane, 3-glycidoxypropyl triethoxysilane, and the like. The addition amount of the silane coupling agent is preferably 0.1% by mass to 5% by mass, and more preferably 0.5% by mass to 3% by mass, based on the solid content of the adhesive. Thereby, the bonding strength with the metal foil can be improved.

Moreover, the adhesive agent of this embodiment may further contain the oxo acid of phosphorus, or its derivative(s). Among phosphorus oxoacids or derivatives thereof, phosphorus oxoacids only need to have at least one free oxoacid, and examples thereof include phosphoric acids such as hypophosphorus acid, phosphorous acid, orthophosphoric acid, and hypophosphorous acid. Condensed phosphoric acid such as metaphosphoric acid, pyrophosphoric acid, tripolyphosphoric acid, polyphosphoric acid, superphosphoric acid, etc. Moreover, as a derivative of the oxoacid of phosphorus, the compound etc. which partially esterified the oxoacid of phosphorus with alcohols in the state which left at least one free oxoacid are mentioned. Examples of these alcohols include aliphatic alcohols such as methanol, ethanol, ethylene glycol, and glycerin, and aromatic alcohols such as phenol, xylenol, hydroquinone, catechol, and phloroglucinol. The oxoacid of phosphorus or its derivative(s) may be used in combination of 2 or more types. The addition amount of the phosphorus oxo acid or its derivative is preferably 0.01% by mass to 10% by mass, more preferably 0.05% by mass to 5% by mass, and particularly preferably 0.1% by mass to 1% based on the solid content of the adhesive. quality%. Thereby, the adhesive strength after immersion in the electrolyte solution can be improved.

The adhesive of the present invention may further contain epoxy phosphate resin. The epoxy phosphate resin is a resin formed by reacting the epoxy group of the epoxy resin with phosphoric acid, the epoxy group is ring-opened, and the epoxy resin part and the phosphoric acid part are bonded by a phosphate bond. Thereby, the adhesive strength after immersion in the electrolyte solution can be improved.

Preferred epoxy phosphate resins are compounds represented by the following general formula (1) and (2).

General formula (1) [Chemical 1]

General formula (2) [Chemical 2]

Examples of epoxy resins reacted with phosphoric acid include bisphenol A-type epoxy resins, bisphenol F-type epoxy resins, phenol novolak-type epoxy resins, bisphenol AD-type epoxy resins, and biphenyl-type epoxy resins. Resin, naphthalene-type epoxy resin, alicyclic epoxy resin, glycidyl ester-type epoxy resin, glycidylamine-type epoxy resin, heterocyclic epoxy resin, diarylidene epoxy resin, terephthalene Phenolic epoxy resins and modified products thereof, etc.

As epoxy phosphate resin, a commercial item can also be used. Specifically, URAD-DD79 (manufactured by DSM, Japan) is preferable. Furthermore, epoxy phosphate resin which has characteristic values equivalent to the said URAD (URAD)-DD79 is also preferable.

The adhesive of this embodiment may contain catechol or a derivative thereof. Specifically, catechol, tert-butylcatechol, epinephrine (adrenaline), noradrenaline (noradrenaline), dopamine (dopamine), nordihydroguaiaretic acid (nordihydroguaiaretic acid), etc. are mentioned. Thereby, the bonding strength with the metal foil can be improved.

The adhesive composition of this embodiment may contain an organic solvent. The organic solvent is not particularly limited, but it is preferable that the material used in the adhesive composition can be dissolved in a single solvent or a mixed solvent, the reactivity with the curing agent (C) is inactive, and the adhesive can be applied. It is removed by overheating volatilization in the drying step. Specific examples of these solvents include aromatic organic solvents such as toluene and xylene; aliphatic organic solvents such as n-hexane and n-heptane; alicyclic organic solvents such as cyclohexane and methylcyclohexane. Solvents; ketone solvents such as methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, etc.; ester solvents such as ethyl acetate and butyl acetate; ethanol, methanol, n-propanol, 2-propanol, butanol , alcohol solvents such as hexanol; diisopropyl ether, butyl cellosolve, tetrahydrofuran, dioxane, butyl carbitol and other ether solvents; diethylene glycol monomethyl ether, triethylene glycol monomethyl ether, propylene glycol Glycol ether solvents such as monomethyl ether; glycol ester solvents such as ethylene glycol monomethyl ether acetate, propylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate, etc. These solvents can be used alone , and two or more of them may be used in combination. Among these solvents, from the viewpoint of the storage stability of the solution of the polyolefin resin (A), the combined use of an aromatic-based organic solvent and a ketone-based solvent, the combined use of an aromatic-based organic solvent and an alcohol-based solvent, and the combined use of an alicyclic organic solvent and an alicyclic solvent are preferred. An organic solvent and a ketone-based solvent are used in combination, and an alicyclic organic solvent is used in combination with an alcohol-based solvent.

In the adhesive composition of this embodiment, well-known additives, such as an adhesion-imparting agent and a plasticizer, may be mix|blended as needed in the range which does not impair the effect of this invention. Examples of the tackifier that can be used in the present embodiment include polyterpene resins, rosin-based resins, aliphatic petroleum resins, alicyclic petroleum resins, copolymerized petroleum resins, styrene resins, and hydrogenated petroleum resins. Resins, etc., the adhesion imparting agent is used for the purpose of improving the adhesive strength. These adhesion-imparting agents may be used alone, or two or more of them may be arbitrarily used in combination. Moreover, as a plasticizer used in this embodiment, liquid rubber, process oil, etc., such as polyisoprene and polybutene, are mentioned.

The adhesive composition of this embodiment is suitable for lamination|stacking of a metal foil (13) and a thermal fusion resin film (15).

<Metal foil> As a metal of the metal foil (13), aluminum, copper, nickel, steel, stainless steel (SUS), etc. are mentioned. These metal foils may be metal foils to which various surface treatments were performed. Examples of the surface treatment include physical treatment such as sand blast treatment and grinding treatment, and surface treatment such as degreasing treatment by vapor deposition, etching treatment, and primer treatment for applying a coupling agent or paint. The treatment agent for forming the surface treatment layer preferably contains a functional group that reacts with the functional group in the hardener (C), and more preferably contains at least one selected from the group consisting of a carboxylic acid group, a hydroxyl group, and an amino group Functional groups are suitable. The amino group here refers to a primary amine, a secondary amine, and an imino group. By providing a surface treatment layer containing such a functional group on the surface of the metal foil (13), when the adhesive composition is thermally cured, the epoxy group in the adhesive layer reacts with the functional group in the surface treatment layer, As a result, a laminate having a high initial bonding strength and excellent electrolyte solution resistance can be obtained, which is preferable.

<Thermal fusion resin film> The thermal fusion resin film ( 15 ) is not particularly limited, but is preferably a polyolefin-based film, and preferably contains an acid-modified compound selected from the group consisting of polyethylene, polypropylene, olefin-based copolymers, and these compounds. An unstretched film of at least one thermoplastic resin from the group consisting of ionic polymers. The thickness of the thermal fusion resin film is not particularly limited, but is preferably 20 μm to 150 μm.

The laminated body formed using the adhesive composition of this embodiment can be obtained as follows, for example. The adhesive composition of the present embodiment is applied to one side of the metal foil (13) (or the heat-sealed resin film (15)), and the solvent is volatilized (dried) to form an uncured adhesive layer. After superimposing a thermal fusion resin film (or metal foil) on the surface of the uncured adhesive layer under pressure at 150°C, the adhesive layer is left to stand at 40°C to 80°C for about 1 to 10 days. After sufficient hardening (also referred to as aging), the metal foil and the thermal fusion resin film are bonded together to obtain a laminate. For the application of the adhesive composition, a normal coater such as a comma coater can be used. In addition, the thickness (amount) of the cured adhesive layer during drying and curing is preferably about 0.5 g/m ² to 10 g/m ² .

The packaging material for electrical storage elements of the present embodiment may be separated from the other side of the metal foil ( 13 ) (the side not in contact with the adhesive layer ( 14 ) on the inner layer side formed from the adhesive composition of the present embodiment). The outer layer side resin film (11) is formed on the outer layer side adhesive layer (12). The resin film (11) on the outer layer side can be preliminarily laminated on the metal foil (13) using an adhesive composition (which may be the same as or different from the adhesive composition of the present embodiment), or the adhesive composition of the present embodiment may be used. After obtaining the laminated body of the metal foil (13) and the thermal fusion resin film (15) by combining the composition, the outer layer side resin film (11) is laminated on the metal foil (13) with the outer layer side adhesive layer (12) interposed therebetween. As the resin film ( 11 ) on the outer layer side to be used, a stretched film such as polyester resin or polyamide resin (nylon) can be mentioned. The outer-layer-side resin film layer ( 11 ) is located on the outer side which is not in contact with the electrolyte solution when the container for an electric storage element is formed using the laminate as a packaging material for an electric storage element.

The storage device container of the present embodiment can be obtained by molding the outer resin film layer ( 11 ) to form a convex surface and the thermal fusion resin film ( 15 ) to form a concave surface using the above-described packaging material for an energy storage device. In addition, the term "concave surface" in this specification refers to a concave surface that can accommodate an electrolyte solution inside when a flat battery packaging material is molded into a tray shape as shown in FIG. 2 . The "convex surface" in this specification refers to the back surface (the surface on the opposite side, the surface on the back side) of the surface having the depression.

A power storage element such as a secondary battery includes a battery body, a plurality of terminals joined to the positive electrode and the negative electrode of the battery body, respectively, a battery container, and an electrolyte solution. The battery container is obtained by laminating a metal foil (13) and a heat-sealing resin film (15) via an adhesive layer (14) formed of the adhesive composition of the present invention, the heat-sealing The resin film is in contact with the electrolyte solution.

The electrolyte solution starts to permeate from the heat-sealing resin film ( 15 ) to the metal foil ( 13 ), but the adhesive layer ( 14 ) formed from the adhesive composition of the present invention is excellent in resistance to the electrolyte solution, so the heat-sealing resin film is The bonding strength to the metal foil is not lowered, and problems such as liquid leakage do not occur. [Example]

Hereinafter, the present invention will be described in more detail by way of examples, but the following examples do not limit the scope of the right of the present invention at all. In addition, each evaluation in an Example was based on the following method. In addition, in an Example, % represents mass %, and a part represents a mass part. <Quantitative determination of acid value> The weighed sample a (g) was dissolved in refluxing xylene, cooled to room temperature, and then titrated with 0.1 M ethanolic potassium hydroxide using phenolphthalein as an indicator. This is quantified. The time at which the color of the indicator remained for 10 seconds was taken as the end point of the titration. The acid value can be obtained from the following formula, assuming that the titration amount is b (mL). Acid value=0.1*b/a

<Weight average molecular weight> The HLC-8220GPC system manufactured by Tosoh Co., Ltd. obtained by connecting two columns of TSKgel superHZM-N was used. Tetrahydrofuran was used as the eluent, and the column temperature was set to 40°C. Measurements were performed at a flow rate of 0.35 mL per minute. The sample was prepared by dissolving 2 mg of polyolefin resin (A) in 5 mL of tetrahydrofuran. In addition, the weight average molecular weight was calculated by standard polystyrene conversion.

<Melting point and melting energy (ΔE)> The melting point and ΔE can be determined by DSC measurement in accordance with JIS K7121. The specific measurement method is as described above.

<Copolymerization composition ratio> The copolymerization composition ratio of polyolefin was calculated|required by the measurement of ¹³ C using the nuclear magnetic resonance (Nuclear Magnetic Resonance, NMR) (JNM-LA400) by JEOL Ltd. make. 20 mg of the sample was dissolved in 1 mL of deuterated chloroform for the determination. The methine group derived from propylene is contained at 25 ppm to 30 ppm, and the methine group derived from 1-butene is contained at 30 ppm to 35 ppm. The copolymerization composition ratio was calculated from the integral ratio of each peak.

<Preparation of polyolefin resin (A)> <Production example 1> As a polyolefin polymerization reaction, 250 mL of purified toluene was put into a glass autoclave with an inner volume of 500 mL replaced with nitrogen, and 0.5 mg in terms of Al atom was charged. of methylaluminoxane, dimethylsilyl-bis-(4,5,6,7,8-pentahydroazulene-2-yl)zirconium dichloride, which is 1.25 μg atoms in terms of Zr atoms, and the temperature rises to 20°C. Next, while supplying propylene at a constant rate of 100 L/hr, 1-butene monomer was continuously supplied at 20° C. to maintain a constant pressure of 1.32 MPa, and polymerization was started. After the polymerization was carried out at 20° C. for 8 hours, isopropanol was added to stop the polymerization. The obtained polymer solution was added to a large amount of methanol to precipitate a polymer. The precipitated polymer was filtered and dried to obtain a polyolefin copolymerized with propylene/1-butene=72/28 (molar ratio). As a monomer graft reaction with polyolefin, 380 g of the obtained polyolefin, 600 g of toluene, and 16 g of maleic anhydride as a graft monomer were charged into a glass-made reaction vessel with an inner volume of 2 L, and the mixture was heated under nitrogen. The solution temperature was set to 100°C by heating and dissolving under flow. After stirring for 1 hour, 4 g of tert-butyl peroxy(2-ethylhexanoate) was added, and the reaction was continued at the same temperature for 4 hours. The polymer solution thus obtained was added to a large amount of methanol while stirring to precipitate a polymer. The precipitated polymer was filtered, washed with methanol several times, and dried to obtain a polyolefin resin (A1). Regarding the obtained polyolefin resin (A1), it was confirmed by GPC measurement that components other than the polyolefin resin (A1) could be removed. The Mw, acid value P, melting point, and ΔE of the polyolefin resin (A1) were 186,000, 0.018 mmol/g, 76°C, and 30 mJ/mg, respectively.

<Production Example 2> During the polyolefin polymerization reaction, propylene was supplied at a flow rate of 20 L/hr, and methylaluminoxane was 0.4 mg in terms of Al atom and 1 μg atom in dichloride in terms of Zr atom was used. Dimethylsilyl-bis-(4,5,6,7,8-pentahydroazulene-2-yl)zirconium, in the grafting reaction with the polyolefin monomer, 388 g of polyolefin was used as the grafting Propylene/1-butane was obtained by the same method as in Production Example 1, except that 10 g of maleic anhydride as a monomer and 2 g of tert-butyl peroxy(2-ethylhexanoate) as a radical initiator were used. A polyolefin resin (A2) obtained by copolymerization of olefin=19/81 (mol ratio). The Mw, acid value P, melting point, and ΔE of the polyolefin resin (A2) were 290,000, 0.06 mmol/g, 58°C, and 27 mJ/mg, respectively.

<Production Example 3> During the polyolefin polymerization reaction, propylene was supplied at a flow rate of 150 L/hr, and during the graft reaction with the polyolefin monomer, 379 g of polyolefin and 15 g of maleic anhydride as the graft monomer were used. , 4 g of lauryl methacrylate, and 2 g of tert-butyl peroxy(2-ethylhexanoate) as a radical initiator, except that the same method as in Production Example 1 was used to obtain propylene/1-butane A polyolefin resin (A3) obtained by copolymerization of olefin = 86/14 (molar ratio). The Mw, acid value P, melting point, and ΔE of the polyolefin resin (A3) were 194000, 0.12 mmol/g, 92°C, and 28 mJ/mg, respectively.

<Production Example 4> During the polyolefin polymerization reaction, propylene was supplied at a flow rate of 85 L/hr, and during the graft reaction with the polyolefin monomer, 350 g of polyolefin and 40 g of maleic anhydride as the graft monomer were used. , 10 g of tert-butyl peroxide (2-ethylhexanoate) as a radical initiator, except that the same method as in Production Example 1 was used to obtain propylene/1-butene=67/33 (molar ratio) copolymerized polyolefin resin (A4). The Mw, acid value P, melting point, and ΔE of the polyolefin resin (A4) were 165,000, 0.3 mmol/g, 74°C, and 28 mJ/mg, respectively.

<Production Example 5> In the polyolefin polymerization reaction, 1.5 mg of methylaluminoxane in terms of Al atom and 3.5 μg of atomic dichloride dimethylsilyl-bis-( in terms of Zr atom were used. 4,5,6,7,8-Pentahydroazulene-2-yl)zirconium, in the graft reaction with the polyolefin monomer, 380 g of polyolefin, 18 g of maleic anhydride as the graft monomer, Except that 2 g of tert-butyl peroxy(2-ethylhexanoate) was used as a radical initiator, it was obtained by the same method as in Production Example 1 with propylene/1-butene=73/27 (mol ratio) ) copolymerized with polyolefin resin (A5). The Mw, acid value P, melting point, and ΔE of the polyolefin resin (A5) were 60,000, 0.12 mmol/g, 76°C, and 26 mJ/mg, respectively.

<Production Example 6> In the polyolefin polymerization reaction, 0.25 mg of methylaluminoxane in terms of Al atom and 0.5 μg of atomic dichloride dimethylsilyl-bis-( in terms of Zr atom were used. 4,5,6,7,8-Pentahydroazulene-2-yl)zirconium, in the graft reaction with the polyolefin monomer, 380 g of polyolefin, 18 g of maleic anhydride as the graft monomer, Except that 2 g of tert-butyl peroxy(2-ethylhexanoate) was used as a radical initiator, it was obtained by the same method as in Production Example 1 with propylene/1-butene=72/28 (mol ratio) ) copolymerized with polyolefin resin (A6). The Mw, acid value P, melting point, and ΔE of the polyolefin resin (A6) were 376,000, 0.11 mmol/g, 77°C, and 26 mJ/mg, respectively.

<Production Example 7> (for comparison) Kuraprene LIR-403 (maleated polyisoprene) manufactured by Kuraprene Co., Ltd. was used as the polyolefin resin (A7). The Mw and the acid value P of the polyolefin resin (A7) were 45,000 and 0.1 mmol/g, respectively, and had no melting point.

<Preparation of polymer (B)> <Production Example 8> SMA2625 (a half-esterified product of a styrene/maleic anhydride copolymer) manufactured by Cray Valley was used as the polymer (B1). The Mw and the acid value X of the polymer (B1) were 9000 and 3.9 mmol/g, respectively.

<Production Example 9> Daiyakaruna 30 (maleic anhydride/α-olefin copolymer having 20 to 28 carbon chains) manufactured by Mitsubishi Chemical Co., Ltd. was used as the polymer (B2). The Mw and the acid value X of the polymer (B2) were 9000 and 1.3 mmol/g, respectively.

<Production Example 10> Joncryl 68 (styrene/acrylic copolymer) manufactured by BASF was used as the polymer (B3). The Mw and the acid value X of the polymer (B3) were 10000 and 3.5 mmol/g, respectively.

<Production Example 11> Pripol 1009 (hydrogenated dimer acid of unsaturated fatty acid) manufactured by Croda was used as the polymer (B4). The Mw and the acid value X of the polymer (B4) were 900 and 2.4 mmol/g, respectively.

<Production Example 12> As the polymer (B5), isobam 600 (maleic anhydride/isobutylene copolymer) manufactured by Kuraray Co., Ltd. was used. The Mw and the acid value X of the polymer (B5) were 7000 and 14.1 mmol/g, respectively.

<Production Example 13> Ricon 130MA20 (maleic acid graft-modified polybutadiene) manufactured by Cray Valley was used as the polymer (B6). The Mw and the acid value X of the polymer (B6) were 6500 and 2.1 mmol/g, respectively.

<Production Example 14> As the polymer (B7), SMA3940 (a half-esterified product of a styrene/maleic anhydride copolymer) manufactured by Cray Valley Co., Ltd. was used. The Mw and the acid value X of the polymer (B7) were 11000 and 1.9 mmol/g, respectively.

<Production Example 15> A 1 L four-neck flask equipped with a stirrer, a thermometer, a reflux condenser, and a nitrogen gas introduction tube was charged with 160 g of methyl ethyl ketone and 38.9 g of maleic anhydride, and a water bath at 90° C. was used while introducing nitrogen gas. Heating and stirring are performed. While maintaining the reflux state, 1.1 g of t-butyl peroxytrimethylacetate was added, and the mixture was heated and stirred for 4 hours to react. After the solvent and unreacted maleic anhydride were distilled off from the solution obtained in the above manner using an evaporator, the solution was sufficiently dried to obtain a maleic acid polymer. The polymer obtained in the manner described above is referred to as polymer (B8). The Mw and acid value X of the polymer (B8) were 250 and 16.9 mmol/g, respectively.

<Production Example 16> A 1-L four-neck flask equipped with a stirrer, a thermometer, a reflux condenser, and a nitrogen gas introduction tube was charged with 150 g of methyl ethyl ketone, and heated and stirred using a 90° C. water bath while introducing nitrogen gas. While maintaining the reflux state, 15 g of methacrylic acid, 40 g of lauryl methacrylate, 45 g of methyl methacrylate, and t-butyl peroxytrimethylacetate were added dropwise using a dropping funnel over 2 hours. A solution in which 1.5 g of ester was uniformly mixed was reacted. After completion of the dropwise addition, heating and stirring were continued for 2 hours, and then 0.15 g of tert-butyl peroxytrimethylacetate was added, followed by further heating and stirring for 3 hours. The resin solution obtained in this manner was concentrated and dried using an evaporator, whereby a polymer (B9) was obtained. The Mw and the acid value X of the polymer (B9) were 9000 and 17.0 mmol/g, respectively.

<Preparation of main ingredient> In a glass container, a total of 20 g of polyolefin resin (A) and polymer (B) were dissolved in 80 g of a mixed solvent of methylcyclohexane/methyl ethyl ketone = 7/3 (weight ratio) to prepare a solid content A resin solution with a concentration of 20% was used as the main agent solution.

<Preparation of hardener> <Example 1 of preparation of hardener> Duranate TPA-100 (trimer of hexamethylene diisocyanate, isocyanate-based TPA-100 manufactured by Asahi Kasei Chemical Co., Ltd.) was placed in a glass container. The amount of functional groups was 5.2 mmol/g) 50 g and 50 g of ethyl acetate were dissolved to obtain a solution with a solid content concentration of 50%. Let it be the hardener (C1).

<Preparation example 2 of hardener> 50 g of jER-604 (tetraglycidyl diaminodiphenylmethane, functional group amount of epoxy group: 10.0 mmol/g) manufactured by Mitsubishi Chemical Co., Ltd. was placed in a glass container , and 50 g of ethyl acetate were dissolved to obtain a solution with a solid content concentration of 50%. Make it hardener (C2).

<Preparation Example 3 of Hardener> In a glass container, Carbodilite V-05 (1,3-bis(2-isocyanato-2-propyl)benzene manufactured by Nisshinbo Chemical Co., Ltd. The condensation reaction product, the functional group amount of carbodiimide group is 3.8 mmol/g, and the functional group amount of isocyanate group is 1.9 mmol/g) 50 g and dissolved to obtain a solid content concentration of 50%. solution. Make it hardener (C3).

<Preparation Example 4 of Hardening Agent> Chemitite PZ-33 (tris(1-aziridine propionic acid) 1,1,1-propanetriyl) manufactured by Nippon Catalyst Co., Ltd. was placed in a glass container The functional group amount of trimethylene group and aziridine group was 6.3 mmol/g) 50 g and 50 g of ethyl acetate were dissolved to obtain a solution having a solid content concentration of 50%. Make it hardener (C4).

<Production of metal foil><Production example 1 of treated aluminum> 3.8 parts of polycarboxylic acid resin (Acryset, EMN-260E, manufactured by Nippon Catalyst Co., Ltd.), 2 parts of orthophosphoric acid and 4 parts of chromium (III) fluoride was dissolved in 990 parts of distilled water, and further 0.2 parts of an oxazoline group-containing polymer (Epocros WS-700, manufactured by Nippon Catalyst Co., Ltd.) was dissolved , thereby preparing a treatment agent 1 with a solid content concentration of 1%. On one side of the degreased aluminum foil (40 μm), the treatment liquid 1 was applied in a dry coating amount of 50 mg/m ² , and dried at 150° C. to obtain a surface treatment layer with AL-1 of the carboxyl group of the polycarboxylic acid resin.

<Production Example 2 of Treated Aluminum> A treatment with a solid content concentration of 1% was prepared by dissolving 1 part of an aminated phenol polymer, 0.5 parts of chromium (III) fluoride, and 2 parts of phosphoric acid in 346.5 parts of distilled water. agent 2. On one side of the degreased aluminum foil (40 μm), the treatment liquid 2 was applied so that the dry coating amount would be 50 mg/m ² , and dried at 150° C. to obtain a surface-treated layer having a surface-treated layer derived from AL-2 of the hydroxyl groups of aminated phenolic polymers.

<Production Example 3 of Treated Aluminum> By mixing 9.1 parts of cerium oxide, 0.9 parts of sodium phosphate, and 90 parts of distilled water, a cerium oxide sol having a solid content concentration of 10% (treatment agent 3) was obtained. On one side of the degreased aluminum foil (40 μm), the treatment liquid 3 was applied so that the dry coating amount would be 80 mg/m ² , and dried at 200° C. to obtain a surface-treated layer having a surface-treated layer derived from AL-3 of the hydroxyl group of phosphoric acid.

<Preparation Example 4 of Treated Aluminum> By mixing 4.5 parts of polyethyleneimine, 0.5 parts of acrylic acid-isopropenyloxazoline copolymer, and 95 parts of distilled water, a treatment agent 4 having a solid content concentration of 5% was prepared. On the surface-treated layer of the treated aluminum AL-3, the treatment liquid 4 was further applied in a dry coating amount of 25 mg/m ² , and dried at 200° C., thereby obtaining a surface treatment layer with polyethylene-derived AL-4 of the amino group of amines.

<Example 1 to Example 23, Comparative Example 1 to Comparative Example 4> Various main ingredient solutions and curing agent solutions were prepared so as to obtain the value of Z/(P*i+Z*j) shown in Table 2. And it diluted with the mixed solvent of methylcyclohexane/methyl ethyl ketone=7/3 (weight ratio), it adjusted to 15% of solid content concentration, and produced the adhesive composition. However, in Example 23, since the solid content concentration was 15% and the viscosity was high, it was adjusted to 10% solid content to prepare an adhesive composition. The laminate of the metal foil and the unstretched polypropylene film described in Table 2 was produced according to the method described later, and the initial bonding strength, the bonding strength after immersion in the electrolyte solution, and the appearance of the molded part after immersion in the electrolyte solution were evaluated.

[Table 1]

[Table 2]

The symbols in Tables 1 and 2 are as follows. LMA: Lauryl methacrylate MMA: Methyl methacrylate MAA: Methacrylic acid

<Performance test> (Preparation of nylon/treated aluminum laminate film) To the untreated surface of treated aluminum, a urethane-based dry lamination adhesive (Toyo) was applied so that the dry coating amount was 4 g/m ² . "AD502/CAT10" manufactured by Toyo Morton Co., Ltd.), after drying at 100°C for 1 minute, a biaxially stretched nylon film having a thickness of 25 μm was attached. Then, the obtained laminate was hardened (aged) for 7 days at 60° C. to sufficiently harden the adhesive. The nylon/treated aluminum laminate film obtained in this manner is hereinafter referred to as "ONY/AL laminate film".

(Preparation of nylon/treated aluminum/unstretched polypropylene laminate film) The adhesives of the examples and comparative examples were applied to the aluminum-treated surface of the ONY/AL laminate film so that the dry coating amount would be 2 g/m ² . After drying at 100 °C for 1 minute, an unstretched polypropylene film (CPP) with a thickness of 30 μm was attached. Then, the obtained laminate was aged at 40° C. for 7 days to sufficiently harden the adhesive. The nylon/treated aluminum/CPP laminate film obtained in this manner is hereinafter referred to as "ONY/AL/CPP laminate film".

(Production of treated aluminum/unstretched polypropylene laminate film) Each adhesive was applied to the treated surface of treated aluminum so that the dry coating amount would be 2 g/m ² , dried at 100° C. for 1 minute, and then attached. CPP with a thickness of 30 μm. Then, the obtained laminate was aged at 40° C. for 7 days to sufficiently harden the adhesive. The treated aluminum/CPP laminate film obtained in this manner is hereinafter referred to as "AL/CPP laminate film".

[Initial bonding strength (before immersion in electrolyte solution)] The AL/CPP laminate film was left to stand for 6 hours in an environment of 25°C and 65% humidity, and then cut into a size of 200 mm × 15 mm, according to ASTM- According to the test method of D1876-61, a T-peel test is performed using a tensile tester at a load speed of 100 mm/min in an environment of 25°C and a humidity of 65%. The peel strength (N/15 mm width) between aluminum foil/CPP is expressed as the average value of 5 test pieces. The results were judged according to the following criteria. ◎: Excellent in practical use: 7 N or more ○: Practical range: 5 N or more and less than 7 N ×: Unpractical: less than 5 N

[Adhesive strength after immersion in electrolyte solution] The same test piece used in the initial adhesive strength test was added to an electrolyte solution [dissolving lithium hexafluorophosphate in ethylene carbonate/diethyl carbonate/dimethyl carbonate=1/ 1/1 (volume ratio), immersed in 1 mol/l lithium hexafluorophosphate solution] for 7 days. Then, the test piece was taken out, washed with running water for about 10 minutes, and after the water was sufficiently wiped off with a paper wiper, the adhesion strength of the test piece was measured in the same manner as the adhesion strength before the immersion test. The measurement results were judged according to the following criteria. ◎: Excellent in practical use: 7 N or more ○: Practical range: 5 N or more and less than 7 N ×: Unpractical: less than 5 N

[Whether there is a change in the appearance of the molded part after immersion in the electrolyte solution] The ONY/AL/CPP laminate film was formed into a billet shape of 110 mm × 180 mm, using a straight die (the long side of the punch shape was 60 mm and the short side was 60 mm). The side is 45 mm, the corner R = 1 mm to 2 mm, the punch shoulder R = 1 mm, the die shoulder R = 0.5 mm) is drawn so that the forming height is 5 mm, and one-stage forming is performed. Next, at 85°C, the formed laminated film was dissolved in an electrolyte solution [dissolving lithium hexafluorophosphate in ethylene carbonate/diethyl carbonate/dimethyl carbonate=1/1/1 (volume ratio) to make 1 mol/l of lithium hexafluorophosphate solution] in immersion for 7 days. Then, the formed laminate film was taken out, washed with running water for about 10 minutes, and after the water was sufficiently wiped off with a paper handkerchief, the presence or absence of a change in the appearance of the AL/CPP surface at the formed portion was visually evaluated. The results were judged according to the following criteria. ◎: Excellent in practical use: no floating and whitening ○: practical range: no floating, but whitening ×: not practical: floating

[table 3]

As shown in Table 3, in Comparative Example 1, since the polymer (B) having a carboxyl group or an acid anhydride group was not contained, the degree of crosslinking of the adhesive was insufficient, and the molded part floated during long-term electrolytic solution immersion.

In Comparative Example 2, the polymer (B) was contained more than 5% by weight with respect to the sum of 100% by weight of the polyolefin resin (A) and the polymer (B), so that the adhesive film became too hard and was immersed in the electrolyte solution. Defects in bonding strength and appearance of the formed part occur.

In Comparative Example 3, since the melting point of the polyolefin resin (A) was not in the range of 55° C. to 100° C., the cohesive force of the adhesive was insufficient, and sufficient initial bonding strength could not be obtained.

In Comparative Example 4, since the curing agent (C) was not contained, a crosslinked structure with the polyolefin resin (A) or the polymer (B) was not formed, the cohesive force of the adhesive was insufficient, and sufficient initial adhesive strength could not be obtained.

On the other hand, in Examples 1 to 23 shown in Table 3, as the polyolefin resin (A), the polyolefin resin (A) contained a preferable amount of weight average molecular weight of 40,000 to 400,000, melting point of 55°C to 100°C, and having Carboxyl group or acid anhydride group polyolefin resin containing, as a curing agent (C), a resin having at least one or more functional groups selected from the group consisting of isocyanate group, epoxy group, carbodiimide group and aziridine group in a preferred amount. The curing agent contains, as the polymer (B), a polymer having a carboxyl group or an acid anhydride group with a weight-average molecular weight of 200 to 130,000 in a preferred amount, so that the initial adhesive strength, the adhesive strength after immersion in an electrolyte solution, The appearance of the molded part after immersion in the electrolyte solution changed.

Among them, the adhesives of Examples 13 to 20 showed excellent performance in all tests. In the adhesives of Examples 13 to 20, the acid value P of the polyolefin resin (A) is in the preferable range of 0.02 to 1.2, so compared with Examples 1 to 3 which are outside the preferable range, the long-term electrolyte solution immersion The post-bonding strength and the appearance of the formed part were excellent. In addition, in the adhesives of Examples 13 to 20, the polyolefin resin (A) is a binary copolymer of propylene and 1-butene, and the copolymerization ratio is propylene:1-butene=40:60-80: Since it is the preferable range of 20, compared with Example 4 - Example 7 outside the preferable range, the initial stage adhesive strength is excellent. In addition, in the adhesive agents of Examples 13 to 20, it is preferable to use 0.5 wt % to 4 wt % with respect to 100 wt % of the sum of the polyolefin resin (A) and the polymer (B) having a carboxyl group or an acid anhydride group. Since the polymer (B) having a carboxyl group or an acid anhydride group was prepared in the range, the adhesive strength after immersion in the electrolyte solution and the appearance of the molded part were excellent compared with Example 8 outside the preferred range. In addition, in the adhesive agents of Examples 13 to 20, since Z/(P*i+X*j) is in the preferable range of 0.5 to 7, compared with Examples 9 to 11 which are outside the preferable range, the initial Both the adhesive strength and the adhesive strength after immersion in the electrolyte solution were excellent. In addition, in the adhesives of Examples 13 to 20, since a curing agent having an isocyanate group or an epoxy group was used as the curing agent, compared with Example 12 in which the curing agent having an aziridine group was used, impregnation with an electrolyte solution The post-bonding strength and the appearance of the formed part were excellent. In addition, in the adhesives of Examples 13 to 20, the polymer (B) having a carboxyl group or an acid anhydride group is a homopolymer (b-1) of an unsaturated carboxylic acid or its acid anhydride, or an unsaturated carboxylic acid or its The polymer (b-2) of an acid anhydride and at least one selected from the group consisting of an aromatic vinyl compound, an aliphatic α-olefin compound, and a conjugated diene compound, so it is not compatible with blending the monomer. Compared with Example 21 of the polymerized polymer (B), the adhesive strength after immersion in the electrolyte solution and the appearance of the molded part were excellent.

INDUSTRIAL APPLICABILITY The adhesive composition of the present invention can be preferably used for packaging materials (laminates) for forming containers of lithium ion batteries, electric double layer capacitors, and lithium ion capacitors and other containers. In addition to this, the adhesive composition of the present invention can be preferably used for forming a packaging material for a container of an electrical storage element, and also for forming a construction, chemical, medical, automotive, etc. that require high adhesive strength and chemical resistance. Laminates in various industrial fields.

11‧‧‧Outer layer side resin film 12‧‧‧Outer layer side adhesive layer 13‧‧‧Metal foil 14‧‧‧Inner layer side adhesive layer 15‧‧‧Hot fusion resin film

FIG. 1 is a schematic cross-sectional view of an embodiment of a packaging material for an electrical storage element according to an embodiment. 2 : is a schematic perspective view of one Embodiment (tray shape) of the container for electrical storage elements of embodiment.

11‧‧‧Resin film on outer side

12‧‧‧Adhesive layer on the outer side

13‧‧‧Metal foil

14‧‧‧Inner layer side adhesive layer

15‧‧‧Hot fusion resin film

Claims (12)

An adhesive composition comprising a polyolefin resin component and a hardener C, the polyolefin resin component comprising: a polyolefin resin A, having a carboxyl group or an acid anhydride group, a melting point of 55° C. to 100° C., and a weight average molecular weight of 40,000 to 40,000° C. 400,000; and polymer B, having a carboxyl group or an acid anhydride group, and having a weight-average molecular weight of 200 to 13,000; the content of polymer B relative to the sum of the polyolefin resin A and polymer B and 100 wt % is 0.2 wt % to 0.2 wt % 5.0% by weight, the hardener C has at least one functional group selected from the group consisting of an isocyanate group, an epoxy group, a carbodiimide group, and an aziridine group. The adhesive composition according to claim 1, wherein the acid value X of the polymer B is 1.2-20 mmol/g. The adhesive composition according to claim 1 or claim 2, wherein the acid value P of the polyolefin resin A is 0.02 to 1.2 mmol/g. The adhesive composition according to claim 1 or claim 2, wherein the polyolefin resin A is set to i grams, the polymer B is set to j grams, and the curing agent is set to When the functional group is Z mmol, Z/(P*i+X*j) is 0.3 to 10. The adhesive composition according to item 1 or item 2 of the claimed scope, wherein the polymer B is a homopolymer b-1 of an unsaturated carboxylic acid or its anhydride, or an unsaturated carboxylic acid or its anhydride, Polymer b-2 with at least one selected from the group consisting of an aromatic vinyl compound, an aliphatic α-olefin compound, and a conjugated diene compound. The adhesive composition according to claim 1 or claim 2, wherein the polyolefin resin A has a melting point of 65°C to 90°C and a weight average molecular weight of 100,000 to 300,000. A laminated body having an adhesive layer between a metal foil and a heat-sealing resin film layer, the adhesive layer being composed of the adhesive composition according to any one of the first to sixth claims in the scope of application form. The laminate according to claim 7, which has a surface-treated layer between the metal foil and the adhesive layer, wherein the surface-treated layer has a functional group that reacts with the curing agent C. Functional group treatment agent formation. The laminate according to claim 8, wherein the functional group in the treatment agent that reacts with the functional group of the curing agent C is at least one selected from the group consisting of a carboxyl group, a hydroxyl group, and an amino group. A packaging material for an electric storage element, which requires an outer-layer side resin film, an outer-layer-side adhesive layer, a metal foil, an inner-layer-side adhesive layer, and a thermal fusion resin film in this order from the outside, wherein the inner-layer-side adhesive layer is composed of, for example, a The adhesive composition described in any one of claims 1 to 6 of the patent application scope is formed. A container for an electric storage element, which is formed of the packaging material for an electric storage element as described in claim 10, wherein a thermal fusion resin film constitutes an inner surface. An electric storage element using the container for an electric storage element as described in claim 11.

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