TWI695870B - Adhesive composition, laminate, electricity storage device packaging material, electricity storage device container, and electricity storage device - Google Patents

Abstract

The present invention provides an adhesive composition that can form a laminate that can be maintained at a high level even when immersed in an electrolyte solution at 85°C for more than two weeks when aged at 40°C for about 3 days . Provided are a laminate, a packaging material for an electrical storage device, a container for an electrical storage device, and an electrical storage device, which are superior in resistance to electrolyte solutions compared to the past. The adhesive composition of the present invention is used to laminate a metal foil layer and a heat seal layer via an adhesive layer, and the adhesive composition is characterized by containing: a polyolefin resin (A) having a carboxyl group or an acid anhydride group, and The epoxy compound (B) obtained by the reaction of the unsaturated fatty acid polymer (B1) and the compound (B2) having two or more epoxy groups.

Description

Adhesive composition, laminate, packaging material for power storage device, container for power storage device, and power storage device

The present invention relates to an adhesive composition. In addition, the present invention relates to a laminate and a packaging material for an electrical storage device formed by laminating a metal foil layer and a heat seal layer using the adhesive composition. Furthermore, the present invention relates to an electric storage device container formed by processing the packaging material for an electric storage device so that the heat seal layer becomes an inner surface, and an electric storage device using the container for an electric storage device.

The secondary battery is a representative power storage device. Due to the rapid growth of electronic devices such as mobile phones and portable personal computers, the need for secondary batteries such as lightweight and small lithium-ion batteries continues to increase. As an external body of a secondary battery, metal cans have been used in the past, and from the viewpoint of weight reduction and productivity, packaging materials in which plastic films or metal foils are laminated have gradually become mainstream.

As the simplest packaging material, a laminate including a resin film layer (11), a metal foil layer (12), an adhesive layer (13), and a heat seal layer (14) in this order from the outer layer side as shown in FIG. 1 can be cited. As shown in FIG. 2, the container for the power storage device is a resin film layer (11) The container is formed by forming a convex surface and a heat-sealing layer (14) forming a concave surface by forming (deep drawing forming, stretch expand forming, etc.) the packaging material. Then, an electrode, an electrolyte solution, and the like are sealed on the concave surface side of the container for a power storage device, and then a battery is manufactured.

In addition, capacitors are also a type of power storage devices, and lithium-ion capacitors are expected to grow in the future market.

Patent Document 1 discloses a compound or polymerization in which an compound having an epoxy group and at least two isocyanate groups in its molecule are blended in an aqueous solution mainly composed of an aqueous latex and/or a water-soluble polymer aqueous solution. Adhesive composition. In addition, Patent Document 2 discloses a polyolefin resin containing (A) having at least one functional group selected from the group consisting of acid anhydride groups, carboxyl groups, and carboxylic acid metal salts in a specific ratio, and (B) having two An adhesive resin composition of an epoxidized vegetable oil having more than one epoxy group and a molecular weight of 3000 or less.

Patent Document 3 discloses a battery exterior body having an adhesive layer containing an acid-modified polypropylene resin and a crosslinking agent in a specific ratio, the acid-modified polypropylene resin containing 70% by mass or more of a propylene component and The acid component contains 0.1% by mass to 10% by mass, and the crosslinking agent includes at least one of an oxazoline compound and an epoxy compound.

Patent Document 4 discloses an epoxy resin-based compound (B) containing an acid-modified polyolefin resin (A) and two or more epoxy groups in one molecule and 10 or more hydroxyl groups in one molecule. Adhesive resin composition.

Patent Document 5 discloses a polyene containing hydroxyl and/or acid groups A laminating adhesive composition for a hydrocarbon resin (A), a phosphoric acid-modified compound (B), and an epoxy resin (C) having an epoxy equivalent of 160 to 1000 (refer to claim 4 and claim 9). Furthermore, the application to the laminate for secondary batteries is disclosed.

[Prior Art Literature]

[Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open No. 55-005937

[Patent Document 2] Japanese Patent No. 3184725

[Patent Document 3] Japanese Patent Laid-Open No. 2012-216364

[Patent Document 4] Japanese Patent Laid-Open No. 2013-91702

[Patent Literature 5] International Publication No. 2014/050686

Among packaging materials for power storage devices, the following properties are mainly required for the adhesive layer for bonding the metal foil layer and the heat seal layer.

(1) The bonding strength between the metal foil layer and the heat seal layer is large.

(2) The adhesive layer described above has electrolyte solution resistance. That is, even if the electrolyte solution is sealed in the battery container, the adhesion strength between the metal foil and the heat seal layer can be maintained.

For example, the electrolyte solution of a lithium battery includes a lithium salt (electrolyte) like lithium hexafluoride phosphate, and solvents such as propyl carbonate, ethyl carbonate, diethyl carbonate, and dimethyl carbonate.

If an electrolyte solution is added to a container for an electricity storage device, the electrolyte solution passes through the heat seal layer and reaches the adhesive layer, thereby causing the adhesive strength of the heat seal layer and the metal foil decline. In addition, when water is immersed in the electrolyte solution from outside the battery container, a lithium salt such as lithium hexafluoride phosphate reacts with water to generate hydrofluoric acid. The generated fluoric acid passes through the heat seal layer and the adhesive layer to reach the metal foil, thereby corroding the metal foil, and the corrosion significantly reduces the bonding strength between the heat seal layer and the metal foil.

Therefore, the adhesive layer for bonding the heat-sealing layer and the metal foil layer is required to have resistance to substances generated by an immersion from outside the power storage device acting on the electrolyte solution in addition to resistance to the electrolyte solution itself.

In addition, in recent years, with the expansion of applications such as in-vehicle and home power storage, power storage devices have been increasingly required to have large capacity and long-term durability. Therefore, particularly in automotive applications, more excellent resistance to electrolyte solutions is required.

Patent Document 1 describes the following purpose: the adhesive composition is used to join Liuan wood sawn timber and asbestos cement board by cold compression bonding, and it also has a certain degree of adhesion after repeated boiling. However, Patent Document 1 does not disclose or suggest battery packaging materials. The moisture resistance of the adhesive strength as described above is completely different from the electrolyte solution resistance.

Patent Document 2 describes the gist: after standing for 48 hours in a thermostatic bath at a temperature of 60° C. and a relative humidity of 90%, the adhesive resin composition is melt-extruded on a polyester film or a polyamide film. The adhesive strength between the resin composition layer and each film can also be maintained to a certain degree. However, Patent Document 2 does not disclose or suggest battery packaging materials. The moisture resistance of the adhesive strength as described above is completely different from the electrolyte solution resistance.

Patent Document 3 discloses a battery exterior material as described above. However, its resistance to electrolytes The solution property is only about 24 hours at 85°C or 100°C.

Patent Literature 4 does not disclose or suggest battery packaging materials. Furthermore, although the initial adhesive strength is described, there is no mention of the durability of the adhesive strength. Of course, there is no suggestion about resistance to electrolyte solutions.

Patent Document 5 discloses the application to the laminate for secondary batteries as mentioned above, and mentions "electrolyte resistance". However, this "electrolyte resistance" is only a level immersed in a simple solvent (ethyl carbonate, propyl carbonate) that does not contain an electrolyte like a lithium salt at 40°C for 30 days. That is, the "electrolyte resistance" in Reference 4 is simply solvent resistance. The resistance to electrolyte solutions containing electrolytes is completely different from the simple solvent resistance.

The present invention is made in view of the above background, and the object is to provide an adhesive composition that can form a laminate that is in an electrolyte solution at 85° C. at 40° C. and an aging time of about 3 days. After immersing for two weeks, the adhesive strength can also be maintained at a high level. In addition, an object of the present invention is to provide a packaging material for an electrical storage device, a container for an electrical storage device, and an electrical storage device that are superior in resistance to electrolyte solutions compared to the prior art.

The inventors found that the epoxy compound (B) obtained by the reaction of the unsaturated fatty acid polymer (B1) and the compound (B2) having two or more epoxy groups is excellent in compatibility with polyolefin, and The hardening reaction is accelerated, thereby completing the present invention.

That is, the present invention relates to an adhesive composition for laminating a metal foil layer and a heat seal layer via an adhesive layer, and the adhesive composition is characterized by containing There are: a polyolefin resin (A) having a carboxyl group or an acid anhydride group, and an epoxy compound obtained by the reaction of a polymer (B1) of unsaturated fatty acid and a compound (B2) having two or more epoxy groups ( B).

The epoxy compound (B) is preferably an epoxy compound obtained by further hydrogenating the reaction product of the unsaturated fatty acid polymer (B1) and the compound (B2) having two or more epoxy groups.

The unsaturated fatty acid polymer (B1) is preferably a compound obtained by dimerizing unsaturated fatty acids having 12 to 24 carbon atoms (dimerizing acid) and trimerizing. At least one of the compounds (trimer acid).

The compound (B2) having two or more epoxy groups is preferably at least one selected from bisphenol A-type epoxy compounds and bisphenol F-type epoxy compounds.

The epoxy equivalent of the epoxy compound (B) is preferably 200 to 7000.

The mass average molecular weight of the polyolefin resin (A) is preferably 50,000 to 500,000.

The polyolefin resin (A) is preferably obtained by further acid-modifying the copolymer obtained from 1-butene and other olefins.

Regarding the adhesive composition of the present invention, when the content of the carboxyl group per gram of the polyolefin resin (A) is X millimoles and the content of the acid anhydride group is Y millimoles, X+2Y is preferred It is 0.05~0.6.

Regarding the adhesive composition of the present invention, the content of the polyolefin resin (A) is P grams and the epoxy group in the epoxy compound (B) is Z millimoles At this time, Z/[(X+2Y)P] is preferably 0.3 to 10.

In addition, the present invention relates to a laminate formed by laminating a metal foil layer and a heat seal layer via an adhesive layer formed from the adhesive composition.

Furthermore, the present invention relates to a packaging material for an electrical storage device in which a resin film layer, a metal foil layer, an adhesive layer, and a heat seal layer are sequentially required from the outer layer, and the packaging material for an electrical storage device is characterized in that the adhesive layer It is formed from the adhesive composition described above.

In addition, the present invention relates to a container for an electric storage device formed of the packaging material for an electric storage device, and a heat seal layer constitutes an inner surface of the container for an electric storage device.

Furthermore, the present invention relates to a power storage device formed by using the container for a power storage device.

The adhesive composition of the present invention can form a laminate that can be maintained at a high level even when immersed in an electrolyte solution at 85°C for two weeks when aged at 40°C for about 3 days.

11: resin film

12: Metal foil layer

13: Adhesive layer

14: heat seal layer

FIG. 1 is a schematic cross-sectional view of an aspect of a packaging material for an electricity storage device of the present invention.

2 is a schematic perspective view of an aspect (tray shape) of a container for a power storage device of the present invention.

The embodiments of the present invention will be described in detail below. In addition, in this specification, the description of "any number A to an arbitrary number B" refers to the range where the index A and the number A are larger, and the number B and the number B are smaller.

As shown in FIG. 1, the packaging material for an electricity storage device of the present invention is formed by laminating at least a resin film layer (11), a metal foil layer (12), an adhesive layer (13), and a heat seal layer (14). The adhesive layer (13) is responsible for bonding the metal foil layer (12) and the heat seal layer (14).

The container for an electricity storage device of the present invention is formed using the packaging material for an electricity storage device of the present invention, and its form is not particularly limited. As a preferable example, a tray-like aspect as shown in FIG. 2 may be mentioned. In this example, a heat-sealing layer (14) is arranged inside the tray, that is, the concave surface forming a space for accommodating electrodes, electrolyte solutions, etc., and a resin film layer on the outer layer side is arranged outside the tray, that is, on the convex surface side ( 11). In addition to the tray shape, a cylindrical shape (cylindrical, rectangular, elliptical, etc.) can be exemplified. These containers for power storage devices are usually obtained by molding and processing a packaging material for power storage devices in a flat state. The inside of the container for an electrical storage device, that is, the surface in contact with the electrolyte solution or the like is a heat seal layer (14). The heat seal layer (14) of the flange portion is opposed to the heat seal layer (14) constituting the packaging material for another power storage device or the heat seal layer (14) of the flange portion of the container for another power storage device. The heat seal layer (14) is welded to each other by contacting and heating, and the storage solution member such as an electrolyte solution and an electrode is sealed.

In addition to the tray shape, the container for a power storage device of the present invention also has a bag-shaped container (pouch type).

The adhesive layer composition of the present invention can be preferably used for an adhesive layer (13) Formation.

The adhesive composition of the present invention contains a polyolefin resin (A) having a carboxyl group or an acid anhydride group, and an epoxy compound (B) modified by a polymer of unsaturated fatty acid. In some cases, the polyolefin resin (A) having a carboxyl group or acid anhydride group is also simply referred to as a polyolefin resin (A), and a polymer (B1) of an unsaturated fatty acid and a compound (B2) having two or more epoxy groups ), the epoxy compound (B) obtained by the reaction is simply referred to as the epoxy compound (B).

In a state where the adhesive composition of the present invention, which is the dried layer before curing, is sandwiched between the metal foil layer (12) and the heat seal layer (14), the polyolefin resin (A) The carboxyl group or acid anhydride group reacts with the epoxy group of the epoxy compound (B). As a result, a strong cross-linked structure can be formed, and sufficient adhesive strength can be exhibited. Even if immersed in a higher temperature electrolyte solution for a long time, the adhesive strength can be maintained at a high level.

<Polyolefin resin with carboxyl group or acid anhydride group (A)>

The polyolefin resin (A) preferably has an amorphous portion. The reason is that the solvent used in the adhesive composition is excellent in solubility, and the solution after the dissolution does not precipitate and is excellent in storage stability that can be stably stored. On the other hand, in order to improve the electrolyte solution resistance of the adhesive layer in the laminate, it is also preferable to have a crystal part. That is, the balance between the amorphous portion and the crystalline portion becomes important. The polyolefin resin (A) used in the present invention preferably has a mass average molecular weight of 50,000 to 500,000, a melting point of 60°C to 110°C, and a melting energy (ΔE) of 15 to 50 (mJ/mg).

With a polyolefin resin (A) mass average molecular weight (Mw) of 50,000 ~500,000, it is easy to make the storage stability of the solution of the polyolefin resin (A) constituting the adhesive composition and the electrolyte solution resistance, heat sealability, and coating properties of the packaging material for electric storage devices coexist. More preferably, the Mw of the polyolefin resin (A) is 100,000 to 400,000.

In other words, if the Mw of the polyolefin resin (A) is less than 50,000, the polymer chain of the polyolefin resin (A) is insufficiently entangled, and thus the film strength of the adhesive layer may decrease and the electrolyte solution resistance may be insufficient. In addition, if the Mw is more than 500,000, the storage stability of the polyolefin resin (A) solution at 25°C may decrease or the viscosity of the adhesive solution may be too high to deteriorate the coating properties.

The melting point of polyolefin resin (A) is 60°C to 110°C, and the melting energy (△E) is 15 to 50 (mJ/mg), which can satisfactorily satisfy the adhesive strength of packaging materials for power storage devices (initial , After the electrolyte solution is immersed) or heat-sealable.

In other words, if the melting point of the polyolefin resin (A) is less than 60°C, there is a possibility that the adhesive strength after impregnation with the electrolyte solution or the heat sealability may decrease. If the melting point is greater than 110°C, the adhesive strength (initial, after the electrolyte solution is immersed) may decrease. More preferably, the melting point of the polyolefin resin (A) is 60°C to 90°C.

In addition, if the melting energy (ΔE) of the polyolefin resin (A) is less than 15 mJ/mg, there may be a decrease in the adhesive strength or heat sealability after the electrolyte solution is immersed, and if it exceeds 50 mJ/mg, the crystallinity may change. High, and the storage stability of the polyolefin resin (A) solution may decrease. More preferably, the melting energy (△E) of the polyolefin resin (A) is 20 mJ/mg to 50 mJ/mg, and further preferably 20 mJ/mg to 40 mJ/mg.

Here, the heat sealability will be described.

For packaging materials for power storage devices, in addition to the In addition to the two properties described at the beginning of the item (then the strength is large and the electrolyte solution resistance is excellent), the heat sealability is also required to be excellent.

The heat seal layer (14) constituting the packaging material for the electricity storage device performs the function of sealing the electricity storage device member such as the electrolyte solution or the electrode into the container for the electricity storage device by heat welding the heat seal layer (14) to each other. It can be considered that from the viewpoint of ensuring a large adhesive strength (peel strength of the heat seal layers (14)), it is preferably high temperature. Heat seal under high pressure.

However, if the adhesive layer (13) bonding the heat seal layer (14) and the metal foil layer (12) is melted or deformed due to heat and pressure during heat sealing, there are electrode terminals and the metal foil layer (12) The risk of continuity. If conduction occurs, it cannot function as a power storage device. Therefore, in order that the insulation between the electrode terminal and the metal foil layer (12) is not damaged by heat sealing, the adhesive layer (13) is required not to melt or deform due to heat and pressure during heat sealing.

By using a polyolefin resin (A) with a melting point and melting energy (△E) within the above range, it can be effectively suppressed. Prevents melting or deformation of the adhesive layer (13) during heat sealing.

Furthermore, in the present invention, "preservation stability" refers to adding resin: 10g to toluene: 90g, heating and dissolving the resin to obtain a transparent solution, then cooling to 25°C, and standing at the same temperature One week without precipitation.

The polyolefin resin (A) in the present invention only needs to have a carboxyl group or an acid anhydride group, and for example, an ethylenically unsaturated carboxyl group or its acid anhydride and a polyolefin resin (A-1) having no carboxyl group or acid anhydride group are bonded Modified polyolefin resin obtained by branch polymerization, or copolymer of olefin monomer and ethylenically unsaturated carboxylic acid or its anhydride, etc. In addition, By reacting the acid anhydride group of the polyolefin having an acid anhydride group with water or alcohol, a polyolefin having a carboxyl group can also be obtained. A modified polyolefin resin obtained by graft-polymerizing an ethylenically unsaturated carboxyl group or its anhydride with a polyolefin resin (A-1) having no carboxyl group or acid anhydride group is preferred. The polyolefin resin (A) may be used alone or in combination of two or more.

The amount of carboxyl groups or acid anhydride groups in the polyolefin resin (A) will be described later.

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

The polyolefin resin (A) is not particularly limited, and for example, refers to the average of olefin monomers such as ethylene, propylene, 1-butene, butadiene, isoprene, 1-hexene, and 1-octene. Polymers, copolymers of olefin monomers or copolymers with other monomers, and polymers such as hydrides or halides of the resulting polymers that have a hydrocarbon skeleton as the main component. The polyolefin resin (A) is preferably a copolymer of olefin monomers.

The copolymer of olefin monomers is preferably a copolymer of 1-butene and other olefin monomers. As other olefins, ethylene and propylene are preferred, and copolymers of 1-butene and other olefin monomers include binary copolymers of ethylene and 1-butene, and binary copolymerization of propylene and 1-butene. The terpolymer of ethylene, propylene and 1-butene is more preferably a binary copolymer of propylene and 1-butene. The copolymerization is more preferably propylene in the molar ratio: 1-butene=10:90~80:20, more preferably 40:60~80:20. In the copolymer of propylene and 1-butene, when the propylene is less than 10 mol%, the melting point is lower than 60°C, and when it is more than 80 mol%, the melting point is higher than 110°C.

The other monomer copolymerizable with the olefin monomer is not particularly limited, examples Examples include aromatic vinyl compounds such as styrene, α-methylstyrene, and indene; methyl (meth)acrylate, ethyl (meth)acrylate, butyl (meth)acrylate, (meth) Hexyl acrylate, octyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, dodecyl (meth)acrylate, stearyl (meth)acrylate, dimethacrylate (meth)acrylate (Meth)acrylic acid alkyl ester compounds such as dodecyl ester; (meth)acrylic acid cyclohexyl ester, (meth)acrylic acid isobornyl ester and other (meth)acrylate compounds having an alicyclic structure; (methyl ) (Meth)acrylate compounds with aromatic rings such as benzyl acrylate; 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, etc. Hydroxy-containing (meth)acrylate compounds; dimethylaminoethyl (meth)acrylate, diethylaminoethyl (meth)acrylate, tert-butylaminoethyl (meth)acrylate (Meth)acrylate compounds with amine groups; (meth)acrylamide, dimethyl (meth)acrylamide, dimethylaminopropyl (meth)acrylamide, isopropyl (Meth) acrylamide, diethyl (meth) acrylamide, hydroxyethyl (meth) acrylamide and other acrylamides; (meth) acrylonitrile, acryl morpholine and the like.

In terms of graft polymerizability and compatibility with polyolefin, 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, and itaconic acid. The These ethylenically unsaturated carboxylic acids or their anhydrides may use only one kind, or may use two or more kinds together.

The polymerization method of the olefin monomer is not particularly limited. For example, a metal catalyst such as Ziegler-Natta catalyst or metallocene catalyst can be added as disclosed in Japanese Patent Publication No. 07-080948. Perform polymerization. In addition, a catalyst promoter such as (meth)aluminoxane may be added as necessary to perform polymerization.

In addition, the Mw of the polyolefin resin (A) is determined as follows.

The HLC-8220 GPC system manufactured by Tosoh Corporation with two TSKgel superHZM-N columns connected was measured at a column temperature of 40° C., an eluent of tetrahydrofuran, and 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, Mw is calculated by standard polystyrene conversion.

When two or more polyolefin resins (A) are used in combination, it means the mass average molecular weight of the entire mixture.

The melting point and melting energy (ΔE) can be determined by differential scanning calorimetry (DSC) in accordance with JIS K7121. Specifically, it is obtained as follows.

The polyolefin resin (A) having a diameter of about 10 mg or each side is used directly when it is 0.5 mm or less, and when it exceeds 0.5 mm, it is cut to 0.5 mm or less and placed in a container.

The melting point is a provisional melting point predicted from the olefin composition (hereinafter referred to as the provisional melting point) or the measurement conditions are changed to obtain the provisional melting point. Then, it is heated at 10°C per minute to a temperature about 30°C higher than the tentative melting point, and then cooled at 10°C per minute to The temperature at which the glass transition temperature (Tg) is about 50°C lower. When a clear Tg cannot be observed, it is cooled to a temperature lower than the provisional melting point by about 50°C. Thereafter, the peak top corresponding to the melting peak exhibited when heated at 10°C per minute to a temperature about 30°C higher than the provisional melting point is set as the melting point. In addition, ΔE is obtained from the area of the portion corresponding to the melting peak from the baseline to the baseline.

When two or more polyolefin resins (A) are used in combination, the melting point is obtained from the peak top of the high-temperature side peak, and ΔE is calculated from the total of all peak areas obtained by melting.

As the polyolefin resin (A), commercially available products can also be used. For example, Sumifitt CK1D (trade name, manufactured by Sumitomo Chemical Co., Ltd.), Unistole P-401, P-802, P-902 (trade name), Umex 1001 , 1010, 2000 (trade name, manufactured by Sanyo Chemical Co., Ltd.), Auroren 350S, 351S, 359S, S-5247S, S-5248S, S-5297S, S-5349S, S-5350S, etc.

In the present invention, in addition to the polyolefin resin (A) having a carboxyl group or acid anhydride group, a polyolefin resin having no carboxyl group or acid anhydride group may be used in combination within a range that does not impair the effects of the invention.

Examples of the polyolefin resin having no carboxyl group or acid anhydride group used in the present invention include Tafthren T3712, T3722, T3522 (propylene elastomer) manufactured by Sumitomo Chemical Co., Ltd., Sumitomo Noblen (polypropylene), manufactured by Mitsui Chemical Co., Ltd. Tafmer DF&A, Tafmer H, Tafmer XM, Tafmer BL, Tafmer M (α-olefin copolymer), Kuraprene LIR-30 (isoprene polymer), LIR-200 (hydrogenated isomeric) manufactured by Kuraray (Pentadiene polymer), LBR-300 (Butadiene polymer), Septon 2002, 2004 (above is hydrogenated styrene-isoprene-styrene copolymer), 2104, 4033, HG252 (above is hydrogenated styrene-made) manufactured by Kuraray (Isoprene/butadiene-styrene copolymer), Asaprene T-432, T-437 manufactured by Asahi Kasei Chemicals, Clayton D1155 manufactured by Clayton Polymer Japan (the above is styrene-butadiene) Diene-styrene copolymer), Tuftec P1500, P2000, MP10 (partially hydrogenated styrene-butadiene-styrene copolymer), H1052, H1043 (above hydrogenated styrene-butadiene- Styrene copolymer), Superchron C (chloride of propylene polymer) manufactured by Japan Paper Chemical Co., Rexpearl EMA (ethylene-methyl acrylate copolymer), Rexpearl EEA (ethylene-ethyl acrylate copolymer) manufactured by Japan Polyethylene Corporation Thing), Mitsui. Evaflex (ethylene-vinyl acetate copolymer) manufactured by Mitsui-DuPont Polychemicals, Bondfast (ethylene-glycidyl methacrylate copolymer) manufactured by Sumitomo Chemical, etc. These can be used alone or in combination of two or more.

Next, the epoxy compound (B) obtained by the reaction of the unsaturated fatty acid polymer (B1) and the compound (B2) having two or more epoxy groups used in the present invention will be described.

The strong cross-linked structure obtained by reacting the epoxy group in the epoxy compound (B) with the carboxyl group or acid anhydride group in the polyolefin resin (A) can exhibit sufficient adhesive strength even after long-term immersion In an electrolyte solution at a higher temperature, the adhesion strength can also be maintained at a high level.

The epoxy compound (B) used in the present invention is not limited to the following As mentioned above, the resin obtained by esterification reaction of the carboxyl group in the polymer (B1) of an unsaturated fatty acid, and the epoxy group in the compound (B2) which has two or more epoxy groups, or its hydrogenation can be mentioned. Thing.

By using an epoxy compound (B) modified with an unsaturated fatty acid polymer (B1), the compatibility with the polyolefin resin (A) can be significantly improved, and the carboxyl group in the polyolefin resin (A) or Acid anhydride group reaction, thereby improving productivity.

Examples of the unsaturated fatty acid polymer (B1) include, for example, dimers, trimers, or oligomers of unsaturated fatty acids, and dimers (dimer acids) and trimers are preferred. (Trimer acid), or a mixture of the two.

Examples of unsaturated fatty acids include oleic acid, elaidic acid, vaccenic acid, ricinoleic acid, codoleic acid, eicosenoic acid, erucic acid, and tetracosenoic acid. Fatty acids based on linoleic acid, linoleic acid, eicosadienoic acid, docosadienoic acid and other fatty acids with two unsaturated groups; eicostrienoic acid, paulownic acid, digo-γ -Fatty acids with three unsaturated groups, such as linoleic acid, pine oil oleic acid, mead acid, and linolenic acid; stearidonic acid and arachidonic acid , Eicosatetraenoic acid, fatty acid with four unsaturated groups, such as eicososatetraenoic acid.

Examples of commercially available products of these polymerized fatty acids include "Pripol 1004", "Pripol 1006", "Pripol 1009", "Pripol 1013", "Pripol 1015", and "Pripol 1015" manufactured by Croda Japan. Pripol 1017", "Pripol 1022", "Pripol 1025", "Pripol 1040", or "Empol 1008", "Empol 1012", "Empol 1016", "Empol 1026", "Empol 1028", "Empol 1043", manufactured by BASF Japan "Empol 1061", "Empol 1062", etc.

Among them, unsaturated fatty acids having 12 to 24 carbon atoms with good compatibility with polyolefin resin (A) and industrially easily available are preferred.

The compound (B2) having two or more epoxy groups may be a compound having two or more epoxy groups in one molecule, and examples of commercially available products include the brand name "Epikote" manufactured by Mitsubishi Chemical Corporation. "828", "Epikote 834", "Epikote 1001", "Epikote 1004", brand names "Epiclon 840", "Epiclon 850", "Epiclon 1050", "Epiclon 2055" manufactured by Dainippon Ink Chemical Industry Co., Ltd., New Day Bisphenol A-type epoxy compounds such as the brand name "Epotohto 128" manufactured by Tetsumi Gold Chemical Co., Ltd.; "Epiclon 830S" manufactured by Dainippon Ink Chemical Industry Co., Ltd., and "Epikote 807" manufactured by Mitsubishi Chemical Corporation, and Nisshin Bisphenol F-type epoxy compounds such as "Epotohto YDF-170", "Epotohto YDF-175", and "Epotohto YDF-2004" manufactured by Tetsumi Chemical Co., Ltd.; and "EBPS-200" manufactured by Nippon Kayaku Co., Ltd. , The trade name "EPX-30" manufactured by Asahi Kasei Chemical Co., Ltd., the trade name "Epiclon EXA1514" manufactured by Dainippon Ink Chemical Industry Co., Ltd., and the bisphenol S type epoxy compound; the trade name "BPFG" manufactured by Osaka Gas Co., Ltd. Phenol stilbene-type epoxy compound, trade names "YL-6056", "YL-6021" manufactured by Mitsubishi Chemical Corporation, "YX-4000", "YX-4000H" and other bixylenol-type or biphenyl-type epoxy compounds, or mixtures of these; Nippon Steel & Sumitomo Chemical Co., Ltd. trade names "Epotohto ST-2004", "ST -2007", "ST-3000" and other hydrogenated bisphenol A-type epoxy compounds; the trade names "Epikote 152" and "Epikote 154" manufactured by Mitsubishi Chemical Corporation, and the trade name "DEN" manufactured by Dow Chemical Corporation "431", "DEN438", trade names "Epiclon N-690", "Epiclon N-695", "Epiclon N-730", "Epiclon N-770", "Epiclon N-770", "Epiclon N-" "865", the brand names "Epotohto YDCN-701" and "Epotohto YDCN-704" manufactured by Nippon Steel & Sumitomo Chemical Co., Ltd., and the product names "EPPN-201", "EOCN-1025" and "EOCN-" Novolac epoxy compounds such as "1020", "EOCN-104S", "RE-306"; the trade name "Epikote YL-903" manufactured by Mitsubishi Chemical Corporation, and the trade name "Epiclon 152" manufactured by Dainippon Ink Chemical Industry Co., Ltd. , "Epiclon 165", Nippon Steel & Sumitomo Chemical Co., Ltd. trade names "Epotohto YDB-400", "Epotohto YDB-500" and other brominated bisphenol A type epoxy compounds; Nippon Steel Chemical Co., Ltd. trade name " ESN-190”, “ESN-360”, epoxy compounds with naphthalene skeleton such as “HP-4032”, “EXA-4700”, and “EXA-4750” manufactured by Dainippon Ink Chemical Industry Co., Ltd.; Dainippon Ink Epoxy compounds with dicyclopentadiene skeleton, such as "HP-7200" and "HP-7200H" manufactured by Chemical Industry Corporation; "YL-933" manufactured by Mitsubishi Chemical Corporation, manufactured by Nippon Kayaku The trade names "EPPN-501", "EPPN-502" and other trihydroxyphenylmethane-type epoxy compounds; Nissan Chemical Co., Ltd. trade name "TEPIC", Mitsubishi Gas Chemical Co., Ltd. "TGI" and other heterocyclic rings Oxygen compounds; trade names "jER 604" and "jER 630" manufactured by Mitsubishi Chemical Corporation, trade names "Epotohto YH-434" manufactured by Nippon Steel & Sumitomo Chemical Corporation, and trade names "Araldite MY720" manufactured by Asahi Kasei Corporation Glycerylamine type epoxy compound; Daicel Chemical Industry Co., Ltd. trade name "Celloxide 2011", Asahi Kasei Industries Co., Ltd. trade name "Araldite CY175", "Araldite CY179", Shin Japan Chemical Co., Ltd. trade name " Alicyclic epoxy compounds such as HBE-100” are not limited to these epoxy compounds. These epoxy compounds may be used alone or in combination of two or more.

Among them, in terms of adhesion, a bisphenol A epoxy compound or a bisphenol F epoxy compound is preferred.

For the reason of excellent pot life, adhesive strength, and chemical resistance, it is obtained by the reaction of a polymer (B1) of an unsaturated fatty acid and a compound (B2) having two or more epoxy groups used in the present invention The epoxy equivalent of the epoxy compound (B) is preferably 200 to 7000. The epoxy equivalent is preferably 200 or more in terms of the length of the pot life of the adhesive composition and the improvement in initial adhesion due to the moderate crosslink density of the adhesive layer. In addition, when the epoxy equivalent is 7000 or less, the crosslink density of the adhesive layer can be increased, the initial adhesive strength can be increased, and the chemical resistance can also be improved. Furthermore, the epoxy equivalent is the number of grams (g/eq) of resin containing 1 gram equivalent of epoxy groups, Calculated by titration method based on JIS K7236.

The esterification reaction of the epoxy compound (B) obtained by the reaction of the unsaturated fatty acid polymer (B1) used in the present invention and the compound (B2) having two or more epoxy groups can be obtained by It proceeds by a well-known reaction. That is, the production method is not particularly limited, and for example, it is synthesized by the reaction of a carboxyl group and an epoxy group using a catalyst. In the presence of a catalyst, the two are brought into contact at a temperature of 50°C to 200°C, preferably 120°C to 180°C for 30 minutes to 20 hours, whereby it can be easily carried out, usually the acid value of the reaction product becomes The time point at which 5 mgKOH/g, preferably 1 mgKOH/g or less became the end point of the reaction.

The catalyst can use halides such as zinc chloride and lithium chloride; N,N-dimethylaniline, pyridine, triethylamine, hexamethylenediamine, diazabicycloundecene and other tertiary amines and Its basic acid or bromate; quaternary ammonium salts such as tetramethylammonium chloride, trimethyldodecylbenzylammonium chloride; sulfonic acids such as p-toluenesulfonic acid, etc.

The epoxy compound (B) obtained by the reaction of the unsaturated fatty acid polymer (B1) and the compound (B2) having two or more epoxy groups can also be obtained as a commercially available product. For example, "Epikote 871", "Epikote 872", "Epikote 872-X-75" manufactured by Mitsubishi Chemical Corporation, "YD-172", "YD-172X75" manufactured by Nippon Steel & Sumitomo Chemical Corporation, etc. may be cited.

Regarding the polyolefin resin (A) used in the present invention, from the viewpoint of excellent adhesiveness and solubility, the content of the carboxyl group per gram of the polyolefin resin (A) is defined as X millimoles or acid anhydride groups. When the content is set to Y millimoles, X+2Y is preferably 0.05 ~0.6.

If X+2Y is less than 0.05, there are few acid groups that become cross-linking points, and cross-linking is insufficient, and sufficient adhesive strength and electrolyte solution resistance may not be obtained. If it is greater than 0.6, the cross-linking shrinkage of the coating film is large, and therefore the adhesive strength may be insufficient or the solubility in the solvent may be reduced.

When the polyolefin resin (A) contained in the adhesive composition is P grams and the epoxy group derived from the epoxy compound (B) is Z millimoles, Z/[(X+2Y )P] The epoxy compound (B) is included in the range of 0.3 to 10, more preferably the epoxy compound (B) is included in the range of 0.5 to 7.

In order to improve the adhesive strength and electrolyte solution resistance, it is preferable that Z/[(X+2Y)P] is 0.3 or more, in order to improve the cohesive force by forming a sufficient cross-linked structure. In terms of resistance to electrolyte solutions, it is preferable that Z/[(X+2Y)P] is 10 or less so that unreacted epoxy compound (B) does not remain.

In order to improve the adhesive strength with the metal foil, the adhesive of the present invention may further contain a silane coupling agent. Examples of the silane coupling agent include trialkoxysilanes having a vinyl group such as vinyltrimethoxysilane, vinyltriethoxysilane, 3-aminopropyltriethoxysilane, and N-(2 -Aminoethyl) 3-aminopropyltrimethoxysilane and other trialkoxysilanes having an amine group, 3-glycidoxypropyltrimethoxysilane, 2-(3,4-ethoxy Cyclohexyl) ethyl trimethoxy silane, 3-glycidoxy propyl triethoxy silane, and the like, and trialkoxy silane having a glycidyl group. The addition amount of the silane coupling agent is based on the solid content of the adhesive, preferably 0.1% by mass to 5% by mass, and more preferably 0.5% by mass to 3% by mass.

In order to improve the adhesive strength with the metal foil, the adhesive of the present invention may contain catechol or a derivative thereof. Specific examples include catechol, tert-butylcatechol, epinephrine, norepinephrine, dopamine, nordihydroguaiaretic acid, and the like.

The adhesive composition of the present invention may contain an organic solvent. As long as the material used in this adhesive composition can be dissolved alone or as a mixed solvent, and reacted with a polymer (B1) of an unsaturated fatty acid and a compound (B2) having two or more epoxy groups The reactivity of the obtained epoxy compound (B) is inert, and can be volatilized and removed by heating in the drying step when the adhesive is applied, and is not particularly limited. Specific examples of these solvents include, for example, aromatic organic solvents such as toluene and xylene; aliphatic organic solvents such as n-hexane and n-heptane; and alicyclic aliphatic solvents such as cyclohexane and methylcyclohexane Organic solvents; ketone solvents such as methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone; ester solvents such as ethyl acetate and butyl acetate; ethanol, methanol, n-propanol, 2-propanol, butyl Alcohol solvents such as alcohol and hexanol; ether solvents such as diisopropyl ether, butyl cellosolve, tetrahydrofuran, dioxane, butyl carbitol; diethylene glycol monomethyl ether, triethylene glycol monomethyl ether , Glycol ether solvents such as propylene glycol monomethyl ether; glycol ester solvents such as ethylene glycol monomethyl ether acetate, propylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate, etc. It can be used alone or in combination. on.

Among these, from the viewpoint of the storage stability of the solution of the polyolefin resin (A), the combined use of an aromatic organic solvent and a ketone solvent, the combined use of an aromatic organic solvent and an alcohol solvent, and a fat are preferred The combined use of a cyclic organic solvent and a ketone solvent, and the combined use of an alicyclic organic solvent and an alcohol solvent.

In the adhesive composition of the present invention, well-known additives such as a tackifier and a plasticizer may be blended as necessary within a range that does not impair the effects of the invention.

Examples of the thickener that can be used in the present invention include polyterpene resins, rosin-based resins, aliphatic petroleum resins, alicyclic petroleum resins, copolymerized petroleum resins, styrene resins, and hydrogenated petroleum resins. Used for the purpose of improving adhesion strength. These can be used alone or in combination of two or more.

In addition, examples of the plasticizer used in the present invention include liquid rubber such as polyisoprene and polybutene, process oil, and the like.

The adhesive composition of the present invention can be preferably used for lamination of a metal foil layer (12) and a heat seal layer (14).

Examples of the metal of the metal foil layer (12) include aluminum, copper, and nickel. These metal foils may be metal foils subjected to various surface treatments. Examples of surface treatments include physical treatments such as sandblasting and polishing treatments, degreasing treatments by vapor deposition, etching treatments, and primer treatments by applying coupling agents or coating agents. The treatment agent for forming the surface treatment layer preferably contains a functional group that reacts with an epoxy group, and more preferably contains at least one functional group selected from the group consisting of carboxylic acid, hydroxyl group, and amine group. The amine group mentioned here means a primary amine, a secondary amine, and an imine group. By including The surface treatment layer of such a functional group is provided on the surface of the metal foil layer (12), and when the adhesive composition is thermally hardened, the epoxy group in the adhesive layer reacts with the functional group in the surface treatment layer, Thereby, a laminate having high initial adhesion strength and excellent electrolyte solution resistance can be obtained.

The heat-sealing layer (14) is not particularly limited, and it is preferably a polyolefin-based film, preferably containing a group selected from the group consisting of polyethylene, polypropylene, olefin-based copolymers, acid-modified products and ionomers of these An unstretched film of at least one thermoplastic resin in the group. The thickness of the heat seal layer is not particularly limited, but is preferably 20 μm to 150 μm.

The laminate formed by using the adhesive composition of the present invention can be obtained as follows, for example.

Apply the adhesive composition of the present invention to one side of the metal foil layer (12) (or heat seal layer (14)), and evaporate (dry) the solvent to form an unhardened adhesive layer at 60°C~150 At ℃, the heat seal layer (14) (or metal foil layer (12)) is superimposed on the surface of the uncured adhesive layer under pressure, and then allowed to stand at 40 ℃ ~ 80 ℃ for 3 days ~ 10 The adhesive layer is sufficiently hardened (also called aging) in about days, and the metal foil and the heat seal layer are bonded together, whereby a laminate can be obtained.

For applying the adhesive composition, a general coater such as a notched wheel coater can be used. In addition, the thickness (amount) of the hardened adhesive layer during drying and hardening is preferably about 0.5 g/m ² to 10 g/m ² .

The packaging material for an electricity storage device of the present invention may be provided with a resin on the other surface of the metal foil layer (12) (the surface not in contact with the adhesive layer (13) formed of the adhesive composition of the present invention) via the outer layer side adhesive layer膜层(11).

For the resin film layer (11), an adhesive composition (which may be the same as or different from the adhesive composition of the present invention) may be used in advance and laminated on the metal foil layer (12), or the adhesive composition of the present invention may be used. After obtaining the laminate of the metal foil layer (12) and the heat seal layer (14), the resin film layer (11) is laminated on the metal foil layer (12) via the outer layer side adhesive layer.

Examples of the resin film layer (11) used include stretched films such as polyester resin and polyamide resin (nylon). When the laminate is used as a packaging material for an electrical storage device to form a container for an electrical storage device, the resin The membrane layer (11) is located outside without contact with the electrolyte solution.

The container for an electricity storage device of the present invention can be obtained by using the packaging material for an electricity storage device described above, and forming the convex surface by the resin film layer (11) on the outer layer side and the concave surface by the heat seal layer (14).

In addition, the "concave surface" mentioned in the present invention means that when the flat packaging material for the power storage device is formed into a tray shape as shown in FIG. The surface at the location, the "convex surface" in the present invention refers to the back surface (the surface on the opposite side, the back surface) of the surface having the recess.

A power storage device 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, a battery container, and an electrolyte solution. The battery container is obtained by laminating a metal foil layer (12) and a heat-sealing layer (14) through an adhesive layer (13) formed of the adhesive composition of the present invention , The heat seal layer is in contact with the electrolyte solution.

The electrolyte solution begins to penetrate from the heat seal layer (14) to the metal foil layer (12), Since the adhesive layer (13) formed of the adhesive composition of the present invention is excellent in resistance to an electrolyte solution, the adhesive strength between the heat seal layer and the metal foil does not decrease, and problems such as liquid leakage do not occur.

[Example]

The present invention will be described in more detail in the following examples, but the following examples do not limit the scope of the present invention. In addition, each evaluation in an Example is based on the following method. In addition, in an Example,% represents a mass %, and a part represents a mass part.

<quantification of carboxyl groups>

The weighed sample a was dissolved in refluxing xylene and cooled to room temperature, and then quantified by titration with 0.1M ethanolic potassium hydroxide using phenolphthalein as an indicator. The time point at which the color development of the indicator remained for 10 seconds was taken as the end point of the titration. If the titration amount is set to b ml, X can be obtained according to the following formula.

X=0.1*b/a

<Quantification of acid anhydride group>

The weighed sample c was dissolved in refluxing xylene and cooled to room temperature, and then octylamine d millimoles or more equivalent to the anhydride group of the sample was added. Using 0.1 M ethanolic perchloric acid, the remaining octylamine was titrated for quantification. When the titration amount is set to e milliliters, Y can be obtained according to the following formula.

Y=(0.1*e-d)/c

<mass average molecular weight>

The HLC-8220 GPC system manufactured by Tosoh Co., Ltd. connected to two TSKgel superHZM-N columns was measured under the conditions that the eluent was tetrahydrofuran, the column temperature was 40° C., and the flow rate was 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 mass average molecular weight is calculated in terms of standard polystyrene.

<melting point, melting energy (△E)>

It was obtained by the same method as described above.

<Copolymerization composition ratio>

The copolymerization composition ratio of polyolefin was determined by measurement of ¹³ C using Nuclear Magnetic Resonance (NMR) (JNM-LA400) manufactured by JEOL Ltd.

20 mg of the sample was dissolved in 1 mL of deuterated chloroform for measurement. The methylene group derived from ethylene has a peak at 40 ppm-50 ppm, the methine group derived from propylene has a peak at 25 ppm-30 ppm, and the methine group derived from 1-butene has a peak at 30 ppm-35 ppm. The copolymerization composition ratio was obtained from the integral ratio of each peak.

<Synthesis Example 1>

Into a 500-mL glass autoclave replaced with nitrogen, 250 mL of purified toluene, 0.5 mg of methyl aluminoxane in terms of Al atoms, and dimethylsilyl group of 1.25 μg in terms of Zr atoms were placed. -Double-(4,5,6,7,8-pentahydroazulene -2-yl) zirconium dichloride, and heated to 40 ℃. Then, ethylene and propylene were supplied at fixed speeds of 50 L/hr and 40 L/hr, respectively, and 1-butene monomer was continuously supplied so as to maintain a fixed pressure of 1.32 MPa at 40° C. to start polymerization. After the polymerization was carried out at 40°C for 8 hours, isopropyl alcohol was added to stop the polymerization. The resulting polymer solution was added to a large amount of methanol to precipitate the polymer. By filtering and drying the precipitated polymer, a polyolefin copolymerized with ethylene/propylene/1-butene=46/33/15 (mole ratio) was obtained.

20 g of the obtained polyolefin and 20 g of cellosolve acetate were charged, and heated and dissolved in a nitrogen stream to make the solution temperature 110°C. It was obtained by dissolving 4 g of maleic anhydride, 2 g of lauryl methacrylate, and 0.6 g of benzoyl peroxide in 239.4 g of cellosolve acetate over 2 hours. After the dropwise addition, the reaction was continued at this temperature for 1 hour. The resulting polymer solution was added to a large amount of methanol to precipitate the polymer. By filtering and drying the precipitated polymer, a polyolefin resin (Al) having an acid anhydride group is obtained.

The Mw, melting point, and ΔE of the polyolefin resin (Al) are 4700, 103°C, and 45 mJ/mg, respectively.

<Synthesis Example 2 to Synthesis Example 4, Synthesis Example 6 to Synthesis Example 12>

A polyolefin resin having an acid anhydride group (A2) was obtained in the same manner as in Synthesis Example 1, except that the flow rate ratio of the mixed gas at the time of olefin polymerization shown in Table 1 and the polymerization temperature, and the amount of monomer added at the time of graft polymerization were obtained. ~ Polyolefin resin (A4), Polyolefin resin (A6) ~ Polyolefin resin (A8).

<Synthesis Example 5>

A polyolefin resin having an acid anhydride group was obtained in the same manner as in Synthesis Example 1 except for the flow rate ratio of the mixed gas shown in Table 1 and the amount of monomer added during graft polymerization. The obtained polyolefin resin was stored in an environment of 85° C. and 85% RH for 3 days, thereby obtaining a polyolefin resin (A5) having a carboxyl group.

<Synthesis Example 9>

In a four-necked flask, 280 g of propylene-ethylene copolymer (propylene/ethylene=82 mass%/18 mass%, mass average molecular weight 85000) was heated and melted under a nitrogen atmosphere, and then the temperature in the system was maintained at 180°C while While stirring, 35.0 g of maleic anhydride as an acid component and 6.0 g of di-tributyl peroxide as a radical generator were added over 2 hours, and then reacted for 1 hour. After the reaction was completed, the obtained reactant was poured into a large amount of acetone to precipitate the resin. Furthermore, the resin was washed several times with acetone to remove unreacted maleic anhydride, and then dried under reduced pressure in a reduced-pressure dryer to obtain an acid-modified polypropylene resin (mass average molecular weight of 40,000).

Using a stirrer equipped with a heat-resistant, pressure-resistant 1 liter volume glass container with a heater, 60.0 g of the acid-modified polypropylene resin, 60.0 g of tetrahydrofuran, and 6.9 g of N,N-dimethylethanolamine ( The carboxyl group of the acid component in the acid-modified polypropylene resin was 1.0 times equivalent) and 173.1 g of distilled water was charged into a glass container, and the stirring blade was rotated at 300 rpm for stirring. As a result, it was not seen at the bottom of the container The precipitation of the resin particulate matter was confirmed to be in a suspended state. Then maintain this state, and turn on the heater power supply for heating after 10 minutes. And keep the temperature in the system at 140 ℃, and then stir for 60 minutes, then cut off the power of the heater and naturally cool to 60 Up to ℃. After cooling, the temperature was maintained at 60° C., the solvent was removed under stirring and reduced pressure, water was added as necessary, and the medium was replaced with water, thereby obtaining an aqueous dispersion of polyolefin resin (A9).

In Table 1, the symbols are as follows.

LMA: lauryl methacrylate

St: Styrene

<Synthesis Example 10>

46g of Pripol 1013 (dimer acid of C18 unsaturated fatty acid, acid value of 196mgKOH/g) manufactured by Croda Japan Co., Ltd., jER 1001 (manufactured by Mitsubishi Chemical Corporation, bisphenol A type epoxy compound, epoxy resin) Equivalent: 475) 154 parts, 4 parts of triphenylphosphine, 160 parts of toluene and 40 parts of isopropanol were heated and dissolved in a nitrogen flask under a nitrogen atmosphere, and the temperature in the system was maintained at 100°C while stirring. anti- The epoxy compound (B-1) having a solid content of 50% and an epoxy equivalent of 1236 should be obtained by cooling until the acid value becomes 1.0 mgKOH/g or less.

<Synthesis Example 11>

14g of Pripol 1010 (dimer acid of C18 unsaturated fatty acid, acid value of 195mgKOH/g) manufactured by Croda Japan Co., Ltd., jER 1007 (manufactured by Mitsubishi Chemical Corporation, bisphenol A type epoxy compound) , Epoxy equivalent is 1975g/eq) 186 parts, 4 parts of triphenylphosphine, 160 parts of toluene and 40 parts of isopropanol in a four-necked flask, heated and dissolved in a nitrogen atmosphere, while maintaining the temperature in the system while stirring It is 100℃. The reaction is performed until the acid value becomes 1.0 mgKOH/g or less, and cooling is performed to obtain an epoxy compound (B-2) having a solid content of 50% and an epoxy equivalent of 4238.

<Synthesis Example 12>

7g of Pripol 1010 (dimer acid of C18 unsaturated fatty acid, acid value of 195mgKOH/g) manufactured by Croda Japan Co., Ltd., and jER 1010 (manufactured by Mitsubishi Chemical Corporation, bisphenol A type epoxy compound) , Epoxy equivalent is 4000g/eq) 193 parts, 4 parts of triphenylphosphine, 160 parts of toluene and 40 parts of isopropanol in a four-necked flask, heated and dissolved in a nitrogen atmosphere, the temperature in the system is maintained while stirring It is 100℃. The reaction was conducted until the acid value became 1.0 mgKOH/g or less, and cooling was performed to obtain an epoxy compound (B-3) having a solid content of 50% and an epoxy equivalent of 8288.

<Synthesis Example 13>

Made Pripol 1004 (C22 not made by Croda Japan) Hydride of dimer acid of saturated fatty acid, acid value is 162mgKOH/g) 109g, jER 630 (manufactured by Mitsubishi Chemical Corporation, glycidylamine epoxy compound, epoxy equivalent is 96g/eq) 91 parts, triphenylphosphine 4 parts, 160 parts of toluene, and 40 parts of isopropyl alcohol were heated and dissolved in a four-necked flask under a nitrogen atmosphere, and the temperature in the system was maintained at 100°C while stirring. The reaction is performed until the acid value becomes 1.0 mgKOH/g or less, and cooling is performed to obtain an epoxy compound (B-4) having a solid content of 50% and an epoxy equivalent of 317.

<Synthesis Example 14>

22g of Pripol 1040 (C18 unsaturated fatty acid trimer acid, acid value 189mgKOH/g) manufactured by Croda Japan Co., Ltd., jER 4005P (manufactured by Mitsubishi Chemical Corporation, bisphenol F type epoxy compound, epoxy (Equivalent to 1175g/eq) 178 parts, 4 parts of triphenylphosphine, 160 parts of toluene and 40 parts of isopropanol in a four-necked flask, heated and dissolved in a nitrogen atmosphere, while maintaining the temperature in the system at 100°C while stirring . The reaction is conducted until the acid value becomes 1.0 mgKOH/g or less, and cooling is performed to obtain an epoxy compound (B-5) having a solid content of 50% and an epoxy equivalent of 3822.

<Synthesis Example 15>

87g of lauric acid (acid value of 200mgKOH/g), 113 parts of TETRAD-C (epoxy equivalent of 91g/eq) manufactured by Mitsubishi Gas Chemical Company, 4 parts of triphenylphosphine, 160 parts of toluene and 40 parts of isopropyl alcohol In a four-necked flask, after heating and dissolving in a nitrogen atmosphere, the temperature in the system was kept at 100°C while stirring. The reaction was conducted until the acid value became 1.0 mgKOH/g or less, and cooling was performed to obtain an epoxy compound (B-6) having a solid content of 50% and an epoxy equivalent of 645.

<Synthesis of additives>

545.5 parts of jER 1001 (manufactured by Mitsubishi Chemical Corporation, bisphenol A epoxy compound, epoxy equivalent weight: 475) and diethylene glycol dimethyl are charged into a reaction vessel equipped with a stirrer, thermometer, reflux cooler and nitrogen introduction tube 259.0 parts of ether was heated to 80°C while being dissolved by heating. After dissolution, 59.7 parts of acrylic acid was charged at 80°C, followed by 0.6 parts of dibutylhydroxytoluene and 2.4 parts of triphenylphosphine, and the temperature was raised to 110°C while stirring for 1 hour. Hold at 110°C for 3 hours, continue the reaction, and reduce the temperature to 80°C when the acid value becomes 1.0 mgKOH/g or less. It takes 1 hour to continuously drop 12.1 parts containing 85% phosphoric acid and 70.2 parts of diethylene glycol dimethyl ether mixture. After the dropwise addition, the reaction was continued at 80°C for 4 hours, and then 50.5 parts of diethylene glycol dimethyl ether was charged, thereby obtaining a phosphoric acid-modified epoxy compound (C having a nonvolatile content of 64.0% and an acid value of 9.0 -1) solution.

<Example 1>

15 parts of polyolefin resin (Al) were heated and dissolved in 117.9 parts of toluene/methyl ethyl ketone (hereinafter referred to as MEK) = 7/3 (weight ratio). After cooling, 5.8 parts of jER 871 (manufactured by Mitsubishi Chemical Co., Ltd., a dimer acid modified epoxy compound having an epoxy equivalent weight of 430) was added and stirred to obtain an adhesive solution having a solid content of 15%.

The adhesive solution was coated on a 40 μm aluminum foil by a bar coater and dried at 100° C. for 1 minute to obtain an adhesive layer with a coating amount of about 2 g/m ² after drying. Then, an unstretched polypropylene film (hereinafter referred to as CPP) with a thickness of 40 μm was superposed on the adhesive layer and passed between two rollers set at 80° C. to obtain a laminate. Thereafter, the obtained laminate was hardened (aged) at 40°C for 3 days or 5 days. In this manner, the obtained aluminum foil/CPP laminated film is referred to as "Al/CPP laminated film" hereinafter.

The initial adhesion strength, solvent resistance, and electrolyte solution resistance were evaluated according to the method described below. The results are shown in Table 2.

<Example 2 to Example 22>, <Comparative Example 1 to Comparative Example 6>

With the compositions shown in Table 2 and Table 3, an adhesive solution and an Al/CPP laminated film were obtained in the same manner as in Example 1, and evaluated in the same manner.

The symbols in Table 2 and Table 3 are as follows.

P-401: "Unistole P-401", manufactured by Mitsui Chemicals, acid-modified polyolefin resin, solid content acid value is 55mgKOH/g, heating residue is 8%

P-902: "Unistole P-902", manufactured by Mitsui Chemicals, acid-modified polyolefin resin, solid component acid value is 55mgKOH/g, heating residue is 22%

jER 871: Dimer acid modified epoxy compound manufactured by Mitsubishi Chemical Corporation (epoxy equivalent of 430g/eq)

YD 172: Dinitrate-modified epoxy compound manufactured by Nippon Steel & Sumitomo Chemical Co., Ltd. (epoxy equivalent of 650g/eq)

jER 630: manufactured by Mitsubishi Chemical Corporation, N,N-bis(2,3-epoxypropyl)-4-(2,3-epoxypropoxy)aniline (epoxy equivalent of 96g/eq)

TETRAD-C: manufactured by Mitsubishi Gas Chemical Company, 1,3-bis(N,N-diglycidylaminomethyl)cyclohexane (epoxy equivalent of 91g/eq)

B-7: Adeka Resin EM-0517 (manufactured by Adeka Corporation, bisphenol A type glycidyl ether type epoxy resin) was diluted with water to a solid concentration of 10%

B-8: Dilution of Basonat HW-100 (a non-block type multifunctional isocyanate compound manufactured by BASF, isocyanate content of about 17%) with water to a solid concentration of 10%

860: "EPICLON 860", a bisphenol A epoxy resin with an epoxy equivalent of 245g/eq manufactured by DIC

TPP: Triphenylphosphine

Mixed solvent 1: toluene/methyl ethyl ketone = 7/3 (mass ratio)

Mixed solvent 2: toluene/isopropanol = 8/2 (mass ratio)

Mixed solvent 3: methylcyclohexane/isopropanol = 8/2 (mass ratio)

[compatibility]

The adhesive solution was coated on a 100 μm PET film by a bar coater, and dried at 100° C. for 1 minute to obtain an adhesive layer with a coating amount of about 2 g/m ² after drying. Regarding this laminated film, the haze was measured in accordance with JIS K7136, and the compatibility was judged by the following criteria.

A: Less than 3

B: Above 3~Under 5

C: 5 or more

[Initial adhesive strength]

After the Al/CPP laminated film was allowed to stand at 25°C and 65% humidity for 6 hours, it was cut to a size of 200 mm × 15 mm, according to the American Society for Testing Material (ASTM)-D1876-61 The test method used a tensile tester to perform a T-peel test at a peeling speed of 100 mm/min in an environment of 25°C and 65% humidity. The peel strength (N) of 15 mm width between aluminum foil/CPP is represented by the average value of 5 test pieces. The judgment is based on the following criteria.

A: 10N or more

B: Above 5N~Under 10N

C: Less than 5N

[Solvent resistance, electrolyte solution resistance (following change in strength)]

The same test piece used in the initial adhesion strength test was immersed in the organic solvent and electrolyte solution described below for two weeks. After that, the test piece was taken out and washed with running water for about 10 minutes. After the water was sufficiently wiped off with the wiping paper, the adhesive strength of the test piece was measured in the same manner as the measurement of the adhesive strength before the immersion test. The judgment is based on the following criteria.

A: The change rate is less than ±10% relative to the initial bonding strength

B: The change rate is less than ±30% relative to the initial bonding strength

C: The rate of change relative to the initial bonding strength is ±30% or more

[Organic solvent]: Ethyl carbonate at 40°C.

[Electrolyte solution]: It is obtained by dissolving lithium hexafluoride phosphate into ethyl carbonate/diethyl carbonate/dimethyl carbonate=1/1/1 (volume ratio) so as to become 1.5 mol/L Solution. The temperature is set at 85°C.

As shown in Example 1 to Example 19 of Table 2, even if the aging period is short, the adhesive strength (initial, after the organic solvent and the electrolyte solution are impregnated) is good.

The adhesive of Comparative Example 1 and Comparative Example 5 is an epoxy compound that does not contain a modified portion of polymerized fatty acid, and has a poor compatibility with polyolefin compared to the epoxy compound (B) of the present invention, so it is aged for a short period of time It is difficult to show the adhesion strength under the following conditions. After being immersed in an organic solvent or electrolyte solution, the adhesion strength decreases significantly.

Regarding the adhesive of Comparative Example 2, in addition to the bisphenol A-type epoxy resin, an isocyanate compound with low solvent resistance is used as the hardener, so it is better than Comparative Example 1. In other words, the solvent resistance is further reduced.

Since the adhesives of Comparative Example 3 and Comparative Example 4 use phosphoric acid-modified epoxy compounds, the solvent resistance is improved compared to Comparative Example 5, but the adhesive strength cannot be sufficiently exhibited under short-term aging.

In the adhesives of Comparative Examples 4 and 6, even if triphenylphosphine which is an acid anhydride or a carboxyl group and a reaction catalyst with an epoxy group or an epoxy compound having an amine group is used, it cannot be sufficiently expressed under short-term aging. Then intensity.

In addition, two laminates (rectangular) of each example were used, and the three sides were heat-sealed so that the CPP became the inner surface to prepare a packet (bag). The two aluminum sheets as analog electrode terminals are not in contact with each other, and are sandwiched between the two open-end laminates for heat sealing. In this case, it is convenient for high temperature (150℃~200℃) and high pressure (0.5kg/cm ² ~3.0kg/cm ² ) under heat sealing, there was no melting or significant deformation of the adhesive layer.

However, in Comparative Example 2 in which an isocyanate compound was used in combination with a hardener, it was at a high temperature. When heat sealing is performed under high pressure, the adhesive melts and overflows from the end. As a result, the simulated electrode terminal is in contact with aluminum, and there is a case where insulation cannot be ensured.

[Industry availability]

The adhesive composition of the present invention can be preferably used as a packaging material (laminate) for forming a container for an electric storage device such as a lithium ion battery, an electric double layer capacitor, a lithium ion capacitor, or the like.

In addition to this, the adhesive composition of the present invention can be preferably used in addition to a packaging material for forming a container for an electrical storage device, such as construction, chemical, medical, automotive, etc., which requires high adhesive strength and chemical resistance Laminates in various industrial fields.

11‧‧‧Resin film

12‧‧‧Metal foil layer

13‧‧‧ Adhesive layer

14‧‧‧Heat seal layer

Claims (11)

An adhesive composition for laminating a metal foil layer and a heat seal layer through an adhesive layer, and the adhesive composition is characterized by containing: a polyolefin resin (A) having a carboxyl group or an acid anhydride group, by The epoxy compound (B) obtained by reacting the unsaturated fatty acid polymer (B1) with the compound (B2) having two or more epoxy groups; the polyolefin resin (A) is obtained by converting 1-butan The copolymer obtained from olefin and other olefin is further acid-modified and obtained when the content of the carboxyl group per gram of the polyolefin resin (A) is X millimoles and the content of the acid anhydride group is Y millimoles , X+2Y is 0.05~0.82. The adhesive composition as described in item 1 of the patent application scope, wherein the epoxy compound (B) is a reaction product of a polymer (B1) of an unsaturated fatty acid and a compound (B2) having two or more epoxy groups Epoxy compound obtained by further hydrogenation. The adhesive composition as described in item 1 or 2 of the patent application, wherein the unsaturated fatty acid polymer (B1) is a compound obtained by dimerizing unsaturated fatty acids having 12 to 24 carbon atoms and At least one of the compounds obtained by trimerization. The adhesive composition according to item 1 or item 2 of the patent application scope, wherein the compound (B2) having two or more epoxy groups is selected from a bisphenol A type epoxy compound and a bisphenol F type epoxy compound At least one of them. The adhesive composition as described in item 1 or item 2 of the scope of patent application, The epoxy equivalent of the epoxy compound (B) is 200-7000. The adhesive composition as described in item 1 or 2 of the patent application range, wherein the polyolefin resin (A) has a mass average molecular weight of 50,000 to 500,000. The adhesive composition as described in item 1 of the patent application range, in which the content of the polyolefin resin (A) is Pg and the epoxy group in the epoxy resin (B) is Z At millimolar, Z/[(X+2Y)P] is 0.3~10. A layered body is formed by laminating a metal foil layer and a heat-sealing layer through an adhesive layer formed from the adhesive composition as described in any one of claims 1 to 7 of the patent application. A packaging material for an electrical storage device requires a resin film layer, a metal foil layer, an adhesive layer, and a heat seal layer in order from the outer layer, and the packaging material for an electrical storage device is characterized in that the adhesive layer is made from a patent The adhesive composition according to any one of items 1 to 7 is formed. A container for an electricity storage device is formed of the packaging material for an electricity storage device as described in item 9 of the patent application range, and a heat seal layer constitutes an inner surface of the container for an electricity storage device. An electricity storage device is formed by using the container for an electricity storage device as described in item 10 of the patent application scope.

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