JP6958567B2 - Battery packaging materials, their manufacturing methods, and batteries - Google Patents

Description

The present invention relates to a packaging material for a battery, a method for producing the same, and a battery.

Conventionally, various types of batteries have been developed, but in all batteries, a packaging material is an indispensable member for sealing a battery element such as an electrode or an electrolyte. Conventionally, metal packaging materials have been widely used for battery packaging.

On the other hand, in recent years, with the improvement of high performance of electric vehicles, hybrid electric vehicles, personal computers, cameras, mobile phones, etc., batteries are required to have various shapes, and are required to be thinner and lighter. However, the metal packaging material for batteries, which has been widely used in the past, has a drawback that it is difficult to keep up with the diversification of shapes and there is a limit to weight reduction.

Therefore, in recent years, as a packaging material for batteries that can be easily processed into various shapes and can be made thinner and lighter, it is in the form of a film in which a base material / aluminum alloy foil layer / heat-sealing resin layer is sequentially laminated. Laminates have been proposed.

In such a packaging material for batteries, recesses are generally formed by cold molding, and battery elements such as electrodes and electrolytic solutions are arranged in the space formed by the recesses, and heat-weldable resin layers are arranged with each other. By heat welding the battery, a battery in which the battery element is housed inside the packaging material for the battery can be obtained. However, such a film-shaped packaging material is thinner than a metal packaging material, and has a drawback that pinholes and cracks are likely to occur during molding. When pinholes or cracks occur in the battery packaging material, the electrolytic solution penetrates into the aluminum alloy foil layer to form metal precipitates, which may result in a short circuit. It is indispensable for the packaging material for a battery to have a property that pinholes are unlikely to occur during molding, that is, excellent moldability. Therefore, a polyamide film may be used as a base material in order to improve moldability. However, when a polyamide film is used as the base material, if the electrolytic solution adheres to the surface of the battery packaging material containing the battery element in the battery manufacturing process, the outer surface is invaded and whitened, resulting in a defective product. Therefore, a polyester film may be used as a base material in order to improve chemical resistance and electrolytic solution resistance. However, the polyester film has a problem that it is harder and inferior in moldability as compared with the polyamide film.

Therefore, conventionally, a packaging material for a battery, which uses a laminate of a polyester film and a polyamide film as a base material and has improved moldability while having chemical resistance and electrolytic solution resistance, is known (see Patent Document 1). ). In recent years, such packaging materials for batteries have been required to have further improved moldability. In a battery packaging material using a laminate of a polyester film and a polyamide film as a base material, even when tensile and compressive stress is applied to the battery packaging material during cold molding, the space between the polyester film and the polyamide film is applied. It is considered necessary that sufficient adhesion and adhesion between the base material and the barrier layer can be ensured, stress applied during molding can be relaxed, and breakage of the barrier layer can be suppressed during molding.

Japanese Unexamined Patent Publication No. 2014-197559

Under such circumstances, it is a main object of the present invention to provide a technique for improving the moldability of a battery packaging material having at least a polyester film layer and a polyamide film layer as a base material layer.

In order to solve the above problems, the present inventors have applied an adhesive layer between a base material layer and a barrier layer and a polyester film and a polyamide in a packaging material for a battery using a laminate of a polyester film and a polyamide film as a base material. As a result of diligent studies on improving moldability by focusing on the adhesive layer between the film and the film, it was found that it is possible to provide a packaging material for batteries that is significantly superior in moldability to conventional packaging materials for batteries. .. That is, in the present invention, in a packaging material for a battery composed of a laminate including at least a base material layer, an adhesive layer, a barrier layer, and a heat-sealing resin layer in this order, the base material layer is a polyester film layer. A first adhesive layer is provided between the adhesive layer and the polyamide film layer, and each of the adhesive layer and the first adhesive layer has a hardness measured by the nanoindentation method of 50 MPa or less, so that the polyester film is formed. Despite having a layer, it was found to be excellent in moldability. The present invention has been completed by further studies based on these findings.

That is, the present invention provides the inventions of the following aspects.
Item 1. It is composed of a laminate having at least a base material layer, an adhesive layer, a barrier layer, and a heat-sealing resin layer in this order.
In the base material layer, a first adhesive layer is provided between the polyester film layer and the polyamide film layer.
The adhesive layer and the first adhesive layer are battery packaging materials having a hardness of 50 MPa or less as measured by the nanoindentation method, respectively.
Item 2. Item 2. The packaging material for a battery according to Item 1, wherein the ratio of the thickness of the polyester film layer to the thickness of the polyamide film layer is in the range of 1: 1 to 1: 5.
Item 3. Item 2. The packaging material for a battery according to Item 1 or 2, wherein the thickness of the adhesive layer is 5 μm or less.
Item 4. Item 2. The packaging material for a battery according to any one of Items 1 to 3, wherein the thickness of the first adhesive layer is 3 μm or less.
Item 5. The adhesive layer is formed of a polyurethane-based adhesive, a polyacrylic-based adhesive, a modified polypropylene-based adhesive, an adhesive containing a silane-based coupling agent, or an adhesive containing a titanate-based coupling agent. The packaging material for a battery according to any one of 1 to 4.
Item 6. Item 2. The item 1 to 5, wherein the first adhesive layer is formed of a resin composition containing a modified thermoplastic resin graft-modified with an unsaturated carboxylic acid or an unsaturated carboxylic acid derivative component. Packaging material for batteries.
Item 7. Item 2. The packaging material for a battery according to any one of Items 1 to 6, wherein an acid-resistant film is provided on at least the surface of the barrier layer on the side of the heat-sealing resin layer.
Item 8. Item 2. The packaging material for a battery according to Item 7, wherein the acid-resistant film contains at least one element selected from the group consisting of phosphorus, chromium and cerium.
Item 9. Item 2. The packaging material for a battery according to Item 7, wherein the acid-resistant film contains at least one selected from the group consisting of phosphates, chromates, fluorides, and triazinethiol compounds.
Item 10. Item 2. The battery packaging material according to Item 7, wherein the acid-resistant film contains a cerium compound.
Item 11. Item 2. The packaging material for a battery according to Item 7, wherein a peak derived from at least one of ^{Ce +} and Cr ⁺ is detected when the acid-resistant film is analyzed by using a time-of-flight secondary ion mass spectrometry method.
Item 12. A battery in which a battery element including at least a positive electrode, a negative electrode, and an electrolyte is housed in a package formed of the battery packaging material according to any one of Items 1 to 11.
Item 13. A method for producing a packaging material for a battery, which comprises a step of laminating at least a base material layer, an adhesive layer, a barrier layer, and a heat-sealing resin layer in this order to obtain a laminate.
The base material layer includes a first adhesive layer between the polyester film layer and the polyamide film layer.
A method for producing a packaging material for a battery, wherein the adhesive layer and the first adhesive layer each have a hardness of 50 MPa or less as measured by a nanoindentation method.

According to the present invention, it is composed of a laminate having at least a base material layer, an adhesive layer, a barrier layer, and a heat-sealing resin layer in this order, and the base material layer includes a polyester film layer and a polyamide film layer. A first adhesive layer is provided between the adhesive layer and the first adhesive layer, and each of the adhesive layer and the first adhesive layer has a hardness measured by the nanoindentation method of 50 MPa or less, so that the battery has excellent moldability. Packaging materials can be provided.

It is a figure which shows an example of the cross-sectional structure of the packaging material for a battery of this invention. It is a figure which shows an example of the cross-sectional structure of the packaging material for a battery of this invention. It is a figure which shows an example of the cross-sectional structure of the packaging material for a battery of this invention.

The packaging material for a battery of the present invention is composed of a laminate having at least a base material layer, a barrier layer, an adhesive layer, and a heat-sealing resin layer in this order. A first adhesive layer is provided between the adhesive layer and the polyamide film layer, and each of the adhesive layer and the first adhesive layer is characterized in that the hardness measured by the nanoindentation method is 50 MPa or less. Hereinafter, the packaging material for a battery of the present invention will be described in detail.

In this specification, the numerical range indicated by "~" means "greater than or equal to" and "less than or equal to". For example, the notation of 2 to 15 mm means 2 mm or more and 15 mm or less.

1. 1. Laminated structure of battery packaging material In the battery packaging material 10 of the present invention, for example, as shown in FIG. 1, the base material layer 1, the adhesive layer 2, the barrier layer 3, and the heat-sealing resin layer 4 are arranged in this order. It is composed of a laminated body to be provided. In the battery packaging material of the present invention, the base material layer 1 is on the outermost layer side, and the heat-sealing resin layer 4 is on the innermost layer. That is, at the time of assembling the battery, the heat-sealing resin layers 4 located on the peripheral edge of the battery element are heat-sealed to each other to seal the battery element, thereby sealing the battery element.

In the base material layer 1, the first adhesive layer 13 is provided between the polyester film layer 11 and the polyamide film layer 12. From the viewpoint of enhancing the electrolytic solution resistance on the outer surface of the battery packaging material, the polyamide film layer 12, the first adhesive layer 13, and the polyester film layer 11 are laminated in this order from the barrier layer 3 side.

In the battery packaging material of the present invention, for example, as shown in FIG. 2, a second adhesive layer is required between the barrier layer 3 and the heat-sealing resin layer 4 for the purpose of enhancing their adhesiveness. 5 may be provided. Further, as shown in FIG. 3, a surface coating layer 6 or the like may be provided on the outside of the base material layer 1 (the side opposite to the heat-sealing resin layer 4), if necessary.

The thickness of the laminate constituting the packaging material for a battery of the present invention is not particularly limited, but is preferably about 160 μm or less from the viewpoint of exhibiting high insulation while making the thickness of the laminate as thin as possible. More preferably, it is about 35 to 155 μm, and further preferably about 45 to 120 μm. According to the present invention, excellent insulating properties can be exhibited even when the thickness of the laminate constituting the packaging material for a battery of the present invention is as thin as 160 μm or less, for example. Therefore, the battery packaging material of the present invention can contribute to the improvement of the energy density of the battery.

2. Each layer forming the packaging material for batteries [Base material layer 1]
In the battery packaging material of the present invention, the base material layer 1 is a layer located on the outermost layer side. In the base material layer 1, a first adhesive layer 13 is provided between the polyester film layer 11 and the polyamide film layer 12. That is, the base material layer 1 has at least a polyester film layer 11, a first adhesive layer 13, and a polyamide film layer 12 in this order.

Specific examples of the polyester constituting the polyester film layer 11 include a copolymerized polyester containing polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polybutylene naphthalate, polyethylene isophthalate, and ethylene terephthalate as repeating units. , Copolymerized polyester containing butylene terephthalate as a repeating unit as a main body, and the like. Further, as the copolymerized polyester having ethylene terephthalate as the main body of the repeating unit, specifically, a copolymer polyester having ethylene terephthalate as the main body of the repeating unit and polymerizing with ethylene isophthalate (hereinafter, polyethylene (terephthalate / isophthalate)). (Abbreviated after), polyethylene (terephthalate / isophthalate), polyethylene (terephthalate / adipate), polyethylene (terephthalate / sodium sulfoisophthalate), polyethylene (terephthalate / sodium isophthalate), polyethylene (terephthalate / phenyl-dicarboxylate) , Polyethylene (terephthalate / decandicarboxylate) and the like. Further, as the copolymerized polyester having butylene terephthalate as the main body of the repeating unit, specifically, a copolymer polyester which polymerizes with butylene isophthalate using butylene terephthalate as the main body of the repeating unit (hereinafter, polybutylene (terephthalate / isophthalate)). (Abbreviated after), polybutylene (terephthalate / adipate), polybutylene (terephthalate / sevacate), polybutylene (terephthalate / decandicarboxylate), polybutylene naphthalate and the like. These polyesters may be used alone or in combination of two or more. Polyester is excellent in electrolytic solution resistance and has an advantage that whitening and the like are unlikely to occur due to adhesion of the electrolytic solution, and is preferably used as a material for forming the base material layer 1.

The polyester film layer 11 is preferably composed of a biaxially stretched polyester film, particularly a biaxially stretched polyethylene terephthalate film.

The thickness of the polyester film layer 11 is not particularly limited, but is preferably about 20 μm or less, more preferably about 1 to 15 μm, and more preferably from the viewpoint of exhibiting excellent moldability while reducing the thickness of the battery packaging material. Is about 3 to 12 μm.

Further, as the polyamide constituting the polyamide film layer 12, specifically, an aliphatic system such as nylon 6, nylon 66, nylon 610, nylon 12, nylon 46, and a copolymer of nylon 6 and nylon 66 is used. Polyamide; hexamethylenediamine-isophthalic acid-terephthal such as nylon 6I, nylon 6T, nylon 6IT, nylon 6I6T (I stands for isophthalic acid, T stands for terephthalic acid) containing a structural unit derived from terephthalic acid and / or isophthalic acid. Acid-copolymerized polyamide, polyamide containing aromatics such as polyamide MXD6 (polymethoxylylen adipamide); alicyclic polyamide such as polyaminomethylcyclohexyl adipamide (PACM6); further lactam component and 4,4'-diphenylmethane -Polyamide obtained by copolymerizing an isocyanate component such as diisocyanate, a polyesteramide copolymer or a polyether esteramide copolymer which is a copolymer of a copolymerized polyamide and polyester or polyalkylene ether glycol; these copolymers, etc. Can be mentioned. These polyamides may be used alone or in combination of two or more. The stretched polyamide film has excellent stretchability, can prevent whitening due to resin cracking of the base material layer 1 during molding, and is suitably used as a material for forming the base material layer 1.

The polyamide film layer 12 is preferably composed of a biaxially stretched polyamide film, particularly a biaxially stretched nylon film.

The thickness of the polyamide film layer 12 is not particularly limited, but is preferably 30 μm or less, more preferably about 1 to 25 μm, and more preferably from the viewpoint of exhibiting excellent moldability while reducing the thickness of the battery packaging material. The size is about 10 to 25 μm.

From the viewpoint of further improving moldability, the ratio of the thickness of the polyester film layer 11 to the thickness of the polyamide film layer 12 (thickness of the polyester film layer 11: thickness of the polyamide film layer 12) in the base material layer 1 is 1. : It is preferably in the range of about 1 to 1: 5, and more preferably in the range of about 1: 1.2 to 1: 4.

In the base material layer 1, the polyester film layer 11 and the polyamide film layer 12 are laminated in order from the barrier layer 3 side, which will be described later, from the viewpoint of improving the electrolytic solution resistance of the battery packaging material. The first adhesive layer 13 and the polyester film layer 11 are laminated in this order.

The present invention is characterized in that the hardness of the first adhesive layer 13 measured by the nanoindentation method is 50 MPa or less. In the packaging material for batteries of the present invention, the adhesive layer 2 described later, wherein the hardness of the first adhesive layer 13 is 50 MPa or less and is located between the base material layer 1 and the barrier layer 3. However, since the hardness measured by the nanoindentation method is 50 MPa or less, excellent moldability can be exhibited. This mechanism can be considered, for example, as follows. That is, since the hardness of these adhesive layers is designed to be smaller than that of a normal adhesive, the base material layer 1 at the time of molding is formed even though the base material layer 1 has the polyester film layer 11. The adhesive layer 2 and the first adhesive layer 13 preferably suppress the sudden deformation of the barrier layer 3 due to the deformation of the barrier layer 3, and as a result, it is effective that cracks and pinholes are generated in the barrier layer 3. It is considered to be suppressed.

From the viewpoint of further improving the moldability of the packaging material for batteries, the hardness of the first adhesive layer 13 is preferably about 10 to 50 MPa, more preferably about 15 to 40 MPa.

In the present invention, the hardness of the adhesive layer 2 and the first adhesive layer 13 measured by the nanoindentation method is a value measured as follows, respectively. As an apparatus, a nanoindenter ((“TriboIndenter TI950” manufactured by HYSITRON)) is used. As an indenter of the nanoindenter, a Berkovich indenter (triangular pyramid) is used. Regarding the hardness of the adhesive layer 2, the hardness of the adhesive layer 2 is adjusted. In an environment of 50% relative humidity and 23 ° C., the indenter was placed on the surface of the adhesive layer 2 of the packaging material for batteries (the surface where the adhesive layer 2 is exposed and perpendicular to the stacking direction of each layer). Apply, push the indenter into the adhesive layer from the surface to a load of 40 μN over 10 seconds, hold for 5 seconds in that state, then unload over 10 seconds. Maximum load P _max (μN) and maximum depth. The indentation hardness (MPa) is calculated by P _max / A using the contact projection area A (μm ² ) at that time, and the load is 10 μN for the hardness of the first adhesive layer 13. Except for this, the measurement can be performed in the same manner as in the adhesive layer 2.

The adhesive used for forming the first adhesive layer 13 preferably includes a resin composition containing a modified thermoplastic resin graft-modified with an unsaturated carboxylic acid or an unsaturated carboxylic acid derivative component. The modified thermoplastic resin preferably includes a resin obtained by modifying a polyolefin-based resin, a styrene-based elastomer, a polyester-based elastomer, or the like with an unsaturated carboxylic acid derivative component. The resin may be used alone or in combination of two or more. Examples of the unsaturated carboxylic acid derivative component include acid anhydrides of unsaturated carboxylic acids and esters of unsaturated carboxylic acids. As the unsaturated carboxylic acid derivative component, one type may be used alone, or two or more types may be used in combination.

Examples of the polyolefin-based resin in the modified thermoplastic resin include low-density polyethylene, medium-density polyethylene, and high-density polyethylene; ethylene-α-olefin copolymer; homo, block or random polypropylene; propylene-α-olefin copolymer; Examples thereof include copolymers obtained by copolymerizing polar molecules such as acrylic acid and methacrylic acid; and polymers such as crosslinked polyolefin. The polyolefin-based resin may be used alone or in combination of two or more.

Examples of the styrene-based elastomer in the modified thermoplastic resin include copolymers of styrene (hard segment) and butadiene or isoprene or hydrogenated products thereof (soft segment). The polyolefin-based resin may be used alone or in combination of two or more.

Examples of the polyester-based elastomer in the modified thermoplastic resin include a copolymer of crystalline polyester (hard segment) and polyalkylene ether glycol (soft segment). The polyolefin-based resin may be used alone or in combination of two or more.

Examples of the unsaturated carboxylic acid in the modified thermoplastic resin include acrylic acid, methacrylic acid, maleic acid, fumaric acid, itaconic acid, citraconic acid, tetrahydrophthalic acid, and bicyclo [2,2,1] hept-2-ene. 5,6-dicarboxylic acid and the like can be mentioned. Examples of the acid anhydride of the unsaturated carboxylic acid include maleic anhydride, itaconic anhydride, citraconic anhydride, tetrahydrophthalic anhydride, and bicyclo [2,2,1] hept-2-ene-5,6-. Dicarboxylic acid anhydride and the like can be mentioned. Examples of the ester of the unsaturated carboxylic acid include methyl acrylate, methyl methacrylate, ethyl methacrylate, butyl methacrylate, dimethyl maleate, monomethyl maleate, diethyl fumarate, dimethyl itacone, diethyl citraconate, and tetrahydro. Examples thereof include esters of unsaturated carboxylic acids such as dimethyl phthalate anhydride and dimethyl bicyclo [2,2,1] hept-2-ene-5,6-dicarboxylic acid.

As the modified thermoplastic resin, about 0.2 to 100 parts by mass of the unsaturated carboxylic acid derivative component is heated and reacted in the presence of a radical initiator with respect to 100 parts by mass of the base thermoplastic resin. It can be obtained by.

The reaction temperature is preferably about 50 to 250 ° C, more preferably about 60 to 200 ° C. The reaction time depends on the production method, but in the case of a melt graft reaction using a twin-screw extruder, it is preferably about 2 to 30 minutes, which is within the residence time of the extruder, and more preferably about 5 to 10 minutes. Further, the denaturation reaction can be carried out under either normal pressure or pressurized conditions.

Examples of the radical initiator used in the modification reaction include organic peroxides. As the organic peroxide, various materials can be selected depending on the temperature condition and the reaction time. For example, alkyl peroxide, aryl peroxide, acyl peroxide, ketone peroxide, peroxyketal, peroxycarbonate, and peroxide can be selected. Examples thereof include oxyesters and hydroperoxides. In the case of the melt graft reaction by the above-mentioned twin-screw extruder, alkyl peroxide, peroxyketal, and peroxyester are preferable, and di-t-butyl peroxide, 2,5-dimethyl-2,5-di-t- It is more preferable to use butylperoxy-hexin-3 and dicumyl peroxide.

The hardness of the first adhesive layer 13 can be determined by adjusting not only the type of resin contained in the adhesive but also the molecular weight of the resin, the number of cross-linking points, the modification rate, the stretching rate, the stretching temperature, and the like. It can be adjusted to the value of.

The thickness of the first adhesive layer 13 is preferably about 0.1 to 5 μm, more preferably about 0.5 to 3 μm.

Further, from the viewpoint of further improving the moldability of the packaging material for batteries, the hardness measured by the nanoindentation method of the polyester film layer 11 is preferably about 300 to 400 MPa, more preferably about 300 to 350 MPa. .. Further, the hardness of the polyamide film layer 12 measured by the nanoindentation method is preferably about 200 to 400 MPa, more preferably about 200 to 350 MPa.

In the present invention, the hardness of the polyester film layer 11 and the polyamide film layer 12 measured by the nanoindentation method is the object of hardness measurement in the above-mentioned method of measuring the hardness of the first adhesive layer 13, respectively. Can be measured in the same manner as the first adhesive layer 13 except that the polyester film layer 11 or the polyamide film layer 12 is used and the pushing load is 100 μN.

In addition to the polyester film layer 11, the first adhesive layer 13, and the polyamide film layer 12, the base material layer 1 may further include other layers. The material forming the other layer is not particularly limited as long as it has an insulating property. Examples of the material forming the other layer include polyester, polyamide, epoxy resin, acrylic resin, fluororesin, polyurethane, silicon resin, phenol resin, polyetherimide, polyimide, and a mixture or copolymer thereof. Be done. When another layer is provided, the thickness of the other layer is preferably about 0.1 to 20 μm, more preferably about 0.5 to 10 μm.

In the present invention, from the viewpoint of improving the moldability of the packaging material for batteries, it is preferable that a lubricant is attached to the surface of the base material layer 1. The lubricant is not particularly limited, but preferably an amide-based lubricant exemplified in the heat-meltable resin layer described later.

When the lubricant is present on the surface of the base material layer 1, the abundance thereof is not particularly limited, but is preferably about 3 mg / m ² or more, more preferably 4 to 15 mg / in an environment of a temperature of 24 ° C. and a relative humidity of 60%. About m ² , more preferably about 5 to 14 mg / m ^2.

The thickness of the base material layer 1 is preferably about 4 μm or more, more preferably about 10 to 75 μm, from the viewpoint of making the battery packaging material excellent in insulating properties while reducing the total thickness of the battery packaging material. , More preferably about 10 to 50 μm.

[Adhesive layer 2]
In the packaging material for batteries of the present invention, the adhesive layer 2 is a layer provided between the base material layer 1 and the barrier layer 3 in order to firmly bond them.

The adhesive layer 2 is formed by an adhesive capable of adhering the base material layer 1 and the barrier layer 3.

The present invention is characterized in that the hardness of the adhesive layer 2 measured by the nanoindentation method is 50 MPa or less. As described above, in the packaging material for batteries of the present invention, the hardness of the first adhesive layer 13 and the adhesive layer 2 measured by the nanoindentation method is 50 MPa or less, so that excellent moldability is exhibited. It becomes possible to do. The method for measuring the hardness of the adhesive layer 2 is as described above.

From the viewpoint of further improving the moldability of the packaging material for batteries, the hardness of the adhesive layer 2 is preferably about 10 to 50 MPa, more preferably about 20 to 40 MPa.

The adhesive used for forming the adhesive layer 2 is not particularly limited as long as it has the above-mentioned hardness after the adhesive layer 2 is formed, and may be a two-component curable adhesive. Alternatively, it may be a one-component curable adhesive. Further, the adhesive mechanism used for forming the adhesive layer 2 is not particularly limited, and may be any of a chemical reaction type, a solvent volatilization type, a heat melting type, a thermal pressure type and the like.

Specific examples of the adhesive component that can be used to form the adhesive layer 2 include polyester resins such as polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polybutylene naphthalate, polyethylene isophthalate, and copolymerized polyester; polyether. Adhesives; Polyethylene adhesives; Epoxy resins; Phenolic resins; Polyethylene resins such as nylon 6, nylon 66, nylon 12, and copolymerized polyamides; Polyethylene resins such as polyolefins, carboxylic acid-modified polyolefins, and metal-modified polyolefins. , Polyvinyl acetate resin; Cellulosic adhesive; (Meta) acrylic resin; Polyethylene resin; Polycarbonate; Amino resin such as urea resin and melamine resin; Rubber such as chloroprene rubber, nitrile rubber, styrene-butadiene rubber; Silicone Examples include based resins. These adhesive components may be used alone or in combination of two or more. Among these adhesive components, a polyurethane-based adhesive is preferable.

The polyurethane-based adhesive is a polyurethane adhesive containing a main agent containing a polyol component (A) and a curing agent containing a polyisocyanate component (B), and the polyol component (A) is a polyester polyol (A1). ), And the polyester polyol (A1) is a polyester polyol having a number average molecular weight of about 5,000 to 50,000 composed of a polybasic acid component and a polyhydric alcohol component, and is aromatic in 100 mol% of the polybasic acid component. Examples thereof include a polybasic acid component containing about 45 to 95 mol%, and the tensile stress at 100% elongation of the adhesive layer is about 100 kg / cm ² or more and about 500 kg / cm ² or less. Further, a polyurethane adhesive for packaging materials for batteries containing a main agent and a polyisocyanate curing agent, wherein the main agent contains 5 to 50% by weight of a polyester polyol (A1) having a glass transition temperature of 40 ° C. or higher and a glass transition temperature. Contains a polyol component (A) containing 95 to 50% by weight of a polyester polyol (A2) having a temperature of less than 40 ° C. and a silane coupling agent (B), and is cured with respect to the total of hydroxyl groups and carboxyl groups derived from the polyol component (A). Examples thereof include those having an equivalent ratio [NCO] / ([OH] + [COOH]) of isocyanate groups contained in the agent of about 1 to 30.

Further, either one or more resins (A) selected from the group consisting of modified polypropylene and polyacrylic resins, or coupling agents (B) containing at least one of a silane coupling agent and a titanate coupling agent. An adhesive containing a resin containing one of them ((A) or (B)) can be mentioned. That is, a polyacrylic adhesive, a modified polypropylene adhesive, an adhesive containing a silane coupling agent, an adhesive containing a titanate coupling agent, and the like can also be preferably used.

The hardness of the adhesive layer 2 includes not only the type of resin contained in the adhesive, but also the molecular weight of the resin, the number of cross-linking points, the ratio of the main agent and the curing agent, the dilution ratio of the main agent and the curing agent, and the drying temperature. By adjusting the aging temperature, aging time, etc., it can be adjusted to the above values.

The thickness of the adhesive layer 2 is not particularly limited as long as it functions as an adhesive layer, and examples thereof include about 1 to 10 μm, preferably about 2 to 5 μm.

[Barrier layer 3]
In the battery packaging material, the barrier layer 3 is a layer that functions as a barrier layer for improving the strength of the battery packaging material and preventing water vapor, oxygen, light, and the like from entering the battery. Specific examples of the metal constituting the barrier layer 3 include aluminum, stainless steel, titanium, and the like, preferably aluminum. The barrier layer 3 can be formed of a metal foil, a metal vapor deposition film, an inorganic oxide vapor deposition film, a carbon-containing inorganic oxide vapor deposition film, a film provided with these vapor deposition films, or the like, and is preferably formed of a metal foil. , It is more preferable to form it with aluminum foil. From the viewpoint of preventing the formation of wrinkles and pinholes in the barrier layer 3 during the manufacture of battery packaging materials, for example, annealed aluminum (JIS H4160: 1994 A8021HO, JIS H4160: 1994 A8079H-O) , JIS H4000: 2014 A8021P-O, JIS H4000: 2014 A8079P-O) and the like, more preferably formed of a soft aluminum foil.

The thickness of the barrier layer 3 is not particularly limited as long as it functions as a barrier layer such as water vapor, but can be, for example, about 10 to 80 μm, preferably about 10 to 50 μm, and more preferably about 10 to 45 μm. ..

Further, the barrier layer 3 is preferably subjected to chemical conversion treatment on at least one surface, preferably both sides, in order to stabilize adhesion, prevent dissolution and corrosion, and the like. Here, the chemical conversion treatment refers to a treatment for forming an acid-resistant film on the surface of the barrier layer. As the chemical conversion treatment, for example, chromic acid chromate using a chromic acid compound such as chromium nitrate, chromium fluoride, chromium sulfate, chromium acetate, chromium oxalate, chromium bicarbonate, acetylacetate chromate, chromium chloride, potassium sulfate. Treatment: Phosphoric acid treatment using a phosphoric acid compound such as sodium phosphate, potassium phosphate, ammonium phosphate, polyphosphate; aminoated phenol weight having a repeating unit represented by the following general formulas (1) to (4). Chromate treatment using coalescence and the like can be mentioned. In the amination phenol polymer, the repeating units represented by the following general formulas (1) to (4) may be contained alone or in any combination of two or more. May be good.

In the general formulas (1) to (4), X represents a hydrogen atom, a hydroxyl group, an alkyl group, a hydroxyalkyl group, an allyl group or a benzyl group. In addition, R ¹ and R ² represent a hydroxyl group, an alkyl group, or a hydroxyalkyl group, respectively, which are the same or different. In the general formulas (1) to (4) ^{, examples of the alkyl group represented by X, R 1} and R ² include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group and an isobutyl group. Examples thereof include linear or branched alkyl groups having 1 to 4 carbon atoms such as tert-butyl groups. Examples of the hydroxyalkyl groups represented by X, R ¹ and R ² include a hydroxymethyl group, a 1-hydroxyethyl group, a 2-hydroxyethyl group, a 1-hydroxypropyl group, a 2-hydroxypropyl group and 3-. A linear or branched chain having 1 to 4 carbon atoms in which one hydroxyl group such as a hydroxypropyl group, a 1-hydroxybutyl group, a 2-hydroxybutyl group, a 3-hydroxybutyl group, or a 4-hydroxybutyl group is substituted. Alkyl groups can be mentioned. In the general formulas (1) to (4), the ^{alkyl group and the hydroxyalkyl group represented by X, R 1} and R ² may be the same or different, respectively. In the general formulas (1) to (4), X is preferably a hydrogen atom, a hydroxyl group or a hydroxyalkyl group. The number average molecular weight of the amination phenol polymer having the repeating unit represented by the general formulas (1) to (4) is preferably, for example, 5 to 1,000,000, and more preferably about 1,000 to 20,000. preferable.

Further, as a chemical conversion treatment method for imparting corrosion resistance to the barrier layer 3, a material obtained by dispersing metal oxides such as aluminum oxide, titanium oxide, cerium oxide and tin oxide and fine particles of barium sulfate is coated in phosphoric acid. A method of forming a corrosion-resistant treatment layer on the surface of the barrier layer 3 by performing a baking treatment at about 150 ° C. or higher can be mentioned. Further, a resin layer obtained by cross-linking a cationic polymer with a cross-linking agent may be further formed on the corrosion-resistant treatment layer. Here, examples of the cationic polymer include polyethyleneimine, an ionic polymer complex composed of polyethyleneimine and a polymer having a carboxylic acid, a primary amine graft acrylic resin obtained by graft-polymerizing a primary amine on an acrylic main skeleton, and polyallylamine. Alternatively, a derivative thereof, aminophenol and the like can be mentioned. As these cationic polymers, only one kind may be used, or two or more kinds may be used in combination. Examples of the cross-linking agent include a compound having at least one functional group selected from the group consisting of an isocyanate group, a glycidyl group, a carboxyl group, and an oxazoline group, a silane coupling agent, and the like. As these cross-linking agents, only one type may be used, or two or more types may be used in combination.

Further, as a method of specifically providing the acid-resistant film, for example, as an example, at least the inner layer side surface of the aluminum alloy foil is first subjected to an alkali dipping method, an electrolytic cleaning method, an acid cleaning method, or an electrolytic acid cleaning method. , The degreasing treatment is performed by a well-known treatment method such as an acid activation method, and then the degreased surface is subjected to a phosphate metal salt such as a chromium phosphate salt, a titanium phosphate salt, a zirconium phosphate salt, a zinc phosphate salt, and these. A treatment solution (aqueous solution) containing a mixture of metal salts as a main component, or a treatment solution (aqueous solution) containing a mixture of a non-metal phosphate and these non-metal salts as a main component, or an acrylic resin containing these. An acid-resistant film is obtained by applying a treatment liquid (aqueous solution) consisting of a mixture of a phenolic resin or an aqueous synthetic resin such as a urethane resin by a well-known coating method such as a roll coating method, a gravure printing method, or a dipping method. Can be formed. For example, when treated with a chromium phosphate salt-based treatment solution, an acid-resistant film composed of chromium phosphate, aluminum phosphate, aluminum oxide, aluminum hydroxide, aluminum fluoride, etc. is formed and treated with a zinc phosphate salt-based treatment solution. If so, the acid-resistant film is made of zinc phosphate hydrate, aluminum phosphate, aluminum oxide, aluminum hydroxide, aluminum fluoride, and the like.

Further, as another example of the specific method for providing the acid-resistant film, for example, at least the inner layer side surface of the aluminum foil is first subjected to an alkali dipping method, an electrolytic cleaning method, an acid cleaning method, an electrolytic acid cleaning method, and an acid activity. An acid-resistant film can be formed by performing a degreasing treatment by a well-known treatment method such as a chemical conversion method, and then performing a well-known anodizing treatment on the degreased surface.

Further, as another example of the acid resistant film, a phosphate-based or chromic acid-based film can be mentioned. Examples of the phosphate system include zinc phosphate, iron phosphate, manganese phosphate, calcium phosphate, chromium phosphate and the like, and examples of the chromic acid system include chromium chromate and the like.

Further, as another example of the acid-resistant film, by forming an acid-resistant film such as a phosphate, a chromate, a fluoride, or a triazinethiol compound, the aluminum and the base material layer at the time of embossing are formed. Prevention of delamination, hydrogen fluoride generated by the reaction of electrolyte and moisture prevents melting and corrosion of aluminum surface, especially aluminum oxide existing on the surface of aluminum from melting and corrosion, and adhesion of aluminum surface. It improves the property (wetability) and shows the effect of preventing the delamination of the base material layer and aluminum during heat sealing, and the effect of preventing the delamination of the base material layer and aluminum during press molding in the embossed type. Among the substances that form an acid-resistant film, an aqueous solution composed of three components of a phenol resin, a chromium (III) fluoride compound, and phosphoric acid is applied to the aluminum surface, and the drying and baking treatment is good.

Further, the acid-resistant film includes a layer having cerium oxide, phosphoric acid or phosphate, an anionic polymer, and a cross-linking agent for cross-linking the anionic polymer, and the phosphoric acid or phosphate is said to be said. 1 to 100 parts by mass may be blended with respect to 100 parts by mass of cerium oxide. The acid-resistant film preferably has a multilayer structure further including a cationic polymer and a layer having a cross-linking agent for cross-linking the cationic polymer.

Further, it is preferable that the anionic polymer is a poly (meth) acrylic acid or a salt thereof, or a copolymer containing (meth) acrylic acid or a salt as a main component. Further, it is preferable that the cross-linking agent is at least one selected from the group consisting of a compound having a functional group of any of an isocyanate group, a glycidyl group, a carboxyl group and an oxazoline group and a silane coupling agent.

Further, it is preferable that the phosphoric acid or phosphate is condensed phosphoric acid or condensed phosphate.

As the chemical conversion treatment, only one type of chemical conversion treatment may be performed, or two or more types of chemical conversion treatments may be combined. Further, these chemical conversion treatments may be carried out by using one kind of compound alone, or by using two or more kinds of compounds in combination. Among the chemical conversion treatments, chromate chromate treatment and chromate treatment in which a chromic acid compound, a phosphoric acid compound, and an amination phenol polymer are combined are preferable.

Specific examples of the acid-resistant film include those containing at least one of phosphate, chromate, fluoride, and triazinethiol compounds. An acid-resistant film containing a cerium compound is also preferable. As the cerium compound, cerium oxide is preferable.

Specific examples of the acid-resistant film include a phosphate-based film, a chromate-based film, a fluoride-based film, and a triazinethiol compound film. The acid-resistant film may be one of these types or a combination of a plurality of types. Further, the acid-resistant film is obtained from a treatment liquid consisting of a mixture of a metal phosphate and an aqueous synthetic resin after degreasing the chemical conversion-treated surface of the barrier layer, or a mixture of a non-metal phosphate and an aqueous synthetic resin. It may be formed by the treatment liquid.

The composition of the acid-resistant film can be analyzed by using, for example, a time-of-flight secondary ion mass spectrometry method. Analysis of the composition of the acid-resistant film using time-of-flight secondary ion mass spectrometry detects, for example, peaks derived from at least one of ^{Ce +} and Cr ^+. Further, phosphoric acid acid-resistant coating, in the case of using phosphate, for example, PO ₃ ^- peak attributable to is detected.

It is preferable that the surface of the aluminum alloy foil is provided with an acid resistant film containing at least one element selected from the group consisting of phosphorus, chromium and cerium. It should be noted that the acid-resistant film on the surface of the aluminum alloy foil of the packaging material for batteries contains at least one element selected from the group consisting of phosphorus, chromium and cerium by using X-ray photoelectron spectroscopy. You can check. Specifically, first, in the packaging material for a battery, the heat-sealing resin layer, the adhesive layer, and the like laminated on the aluminum alloy foil are physically peeled off. Next, the aluminum alloy foil is placed in an electric furnace at about 300 ° C. for about 30 minutes to remove organic components existing on the surface of the aluminum alloy foil. Then, the surface of the aluminum alloy foil is confirmed to contain these elements by using X-ray photoelectron spectroscopy.

The amount of the acid-resistant film formed on the surface of the barrier layer 3 in the chemical conversion treatment is not particularly limited, but for example, in the case of performing the above chromate treatment, the chromic acid compound is contained per ^{1 m 2 of the surface of the barrier layer 3.} Chromate equivalent is about 0.5 to 50 mg, preferably about 1.0 to 40 mg, phosphorus compound is about 0.5 to 50 mg, preferably about 1.0 to 40 mg, and amination phenol polymer is about 1 to 1. It is desirable that it is contained in a proportion of about 200 mg, preferably about 5.0 to 150 mg.

The thickness of the acid-resistant film is not particularly limited, but is preferably about 1 nm to 20 μm, more preferably about 1 to 100 nm, from the viewpoint of the cohesive force of the film and the adhesion to the barrier layer and the heat-sealing resin layer. , More preferably about 1 to 50 nm. The thickness of the acid-resistant film can be measured by observation with a transmission electron microscope or a combination of observation with a transmission electron microscope and energy dispersion type X-ray spectroscopy or electron beam energy loss spectroscopy.

In the chemical conversion treatment, a solution containing a compound used for forming an acid-resistant film is applied to the surface of the barrier layer by a bar coating method, a roll coating method, a gravure coating method, a dipping method, or the like, and then the temperature of the barrier layer is 70. This is done by heating to about ~ 200 ° C. Further, before the barrier layer is subjected to the chemical conversion treatment, the barrier layer may be subjected to a degreasing treatment by an alkali dipping method, an electrolytic cleaning method, an acid cleaning method, an electrolytic acid cleaning method or the like in advance. By performing the degreasing treatment in this way, it becomes possible to more efficiently perform the chemical conversion treatment on the surface of the barrier layer.

[Heat-sealing resin layer 4]
In the battery packaging material of the present invention, the heat-sealing resin layer 4 corresponds to the innermost layer, and is a layer in which the heat-sealing resin layers are heat-sealed to seal the battery element when the battery is assembled.

The resin component used in the heat-fusing resin layer 4 is not particularly limited as long as it can be heat-fused, and examples thereof include polyolefins, cyclic polyolefins, carboxylic acid-modified polyolefins, and carboxylic acid-modified cyclic polyolefins. Be done. That is, the heat-sealing resin layer 4 may contain a polyolefin skeleton, and preferably contains a polyolefin skeleton. The fact that the heat-sealing resin layer 4 contains a polyolefin skeleton can be analyzed by, for example, infrared spectroscopy, gas chromatography-mass spectrometry, or the like, and the analysis method is not particularly limited. For example, when measuring the infrared spectroscopy at a maleic anhydride-modified polyolefin, a peak derived from maleic acid is detected in the vicinity of the wave number of 1760 cm ^-1 and near the wave number 1780 cm ^-1. However, if the degree of acid denaturation is low, the peak may become small and may not be detected. In that case, it can be analyzed by nuclear magnetic resonance spectroscopy.

Specific examples of the polyolefin include polyethylene such as low-density polyethylene, medium-density polyethylene, high-density polyethylene, and linear low-density polyethylene; homopolypropylene, polypropylene block copolymer (for example, propylene and ethylene block copolymer), and polypropylene. Polypropylene such as a random copolymer of polyethylene (eg, a random copolymer of propylene and ethylene); a polyethylene-butene-propylene tarpolymer; etc. Among these polyolefins, polyethylene and polypropylene are preferable.

The cyclic polyolefin is a copolymer of an olefin and a cyclic monomer, and examples of the olefin that is a constituent monomer of the cyclic polyolefin include ethylene, propylene, 4-methyl-1-pentene, styrene, butadiene, and isoprene. Can be mentioned. Examples of the cyclic monomer which is a constituent monomer of the cyclic polyolefin include cyclic alkenes such as norbornene; specific examples thereof include cyclic diene such as cyclopentadiene, dicyclopentadiene, cyclohexadiene, and norbornadiene. Among these polyolefins, cyclic alkene is preferable, and norbornene is more preferable.

The carboxylic acid-modified polyolefin is a polymer modified by block-polymerizing or graft-polymerizing the polyolefin with a carboxylic acid. Examples of the carboxylic acid used for modification include maleic acid, acrylic acid, itaconic acid, crotonic acid, maleic anhydride, itaconic anhydride and the like.

The carboxylic acid-modified cyclic polyolefin means that a part of the monomer constituting the cyclic polyolefin is copolymerized in place of α, β-unsaturated carboxylic acid or an anhydride thereof, or α, β with respect to the cyclic polyolefin. -A polymer obtained by block polymerization or graft polymerization of unsaturated carboxylic acid or its anhydride. The same applies to the cyclic polyolefin modified with carboxylic acid. The carboxylic acid used for the modification is the same as that used for the modification of the polyolefin.

Among these resin components, carboxylic acid-modified polyolefin is preferable; and carboxylic acid-modified polypropylene is more preferable.

The heat-sealing resin layer 4 may be formed of one type of resin component alone, or may be formed of a blended polymer in which two or more types of resin components are combined. Further, the heat-sealing resin layer 4 may be formed of only one layer, or may be formed of two or more layers with the same or different resin components.

Further, the heat-sealing resin layer 4 may contain a lubricant or the like, if necessary. When the heat-sealing resin layer 4 contains a lubricant, the moldability of the battery packaging material can be improved. The lubricant is not particularly limited, and a known lubricant can be used. Examples thereof include those exemplified in the above-mentioned base material layer 1. The lubricant may be used alone or in combination of two or more. The amount of the lubricant present on the surface of the heat-sealing resin layer 4 is not particularly limited, and from the viewpoint of improving the moldability of the electronic packaging material, it is preferably 10 to 10 in an environment of a temperature of 24 ° C. and a relative humidity of 60%. 50 mg / m ² about, even more preferably include about 15~40mg / m ^2.

The thickness of the heat-sealing resin layer 4 is not particularly limited as long as it functions as a heat-sealing resin layer, but is, for example, about 100 μm or less, preferably about 85 μm or less, and more preferably 15 to 85 μm. Can be mentioned. For example, when the thickness of the second adhesive layer 5 described later is about 10 μm or more, the thickness of the heat-sealing resin layer 4 is preferably about 60 μm or less, more preferably about 15 to 45 μm. For example, when the thickness of the second adhesive layer 5 described later is less than 10 μm or when the second adhesive layer 5 is not provided, the thickness of the heat-sealing resin layer 4 is preferably about 20 μm or more. , More preferably about 35 to 85 μm.

[Second adhesive layer 5]
In the packaging material for batteries of the present invention, the second adhesive layer 5 is a layer provided as necessary between the barrier layer 3 and the heat-sealing resin layer 4 in order to firmly bond them.

The second adhesive layer 5 is formed of a resin capable of adhering the barrier layer 3 and the heat-sealing resin layer 4. As the resin used for forming the second adhesive layer 5, the same adhesive mechanism and the type of adhesive component as those exemplified in the adhesive layer 2 can be used. Further, as the resin used for forming the second adhesive layer 5, polyolefin-based resins such as the polyolefin, cyclic polyolefin, carboxylic acid-modified polyolefin, and carboxylic acid-modified cyclic polyolefin exemplified in the above-mentioned heat-sealing resin layer 4 are also used. Can be used. From the viewpoint of excellent adhesion between the barrier layer 3 and the heat-sealing resin layer 4, the polyolefin is preferably a carboxylic acid-modified polyolefin, and particularly preferably a carboxylic acid-modified polypropylene. That is, the second adhesive layer 5 may contain a polyolefin skeleton, and preferably contains a polyolefin skeleton. The fact that the second adhesive layer 5 contains a polyolefin skeleton can be analyzed by, for example, infrared spectroscopy, gas chromatography-mass spectrometry, or the like, and the analysis method is not particularly limited. For example, when measuring the infrared spectroscopy at a maleic anhydride-modified polyolefin, a peak derived from maleic acid is detected in the vicinity of the wave number of 1760 cm ^-1 and near the wave number 1780 cm ^-1. However, if the degree of acid denaturation is low, the peak may become small and may not be detected. In that case, it can be analyzed by nuclear magnetic resonance spectroscopy.

Further, from the viewpoint of making the battery packaging material excellent in shape stability after molding while reducing the thickness of the battery packaging material, the second adhesive layer 5 is a resin composition containing an acid-modified polyolefin and a curing agent. It may be a cured product of. As the acid-modified polyolefin, preferably, the same ones as the carboxylic acid-modified polyolefin and the carboxylic acid-modified cyclic polyolefin exemplified in the heat-sealing resin layer 4 can be exemplified.

The curing agent is not particularly limited as long as it cures the acid-modified polyolefin. Examples of the curing agent include an epoxy-based curing agent, a polyfunctional isocyanate-based curing agent, a carbodiimide-based curing agent, and an oxazoline-based curing agent.

The epoxy-based curing agent is not particularly limited as long as it is a compound having at least one epoxy group. Examples of the epoxy-based curing agent include epoxy resins such as bisphenol A diglycidyl ether, modified bisphenol A diglycidyl ether, novolak glycidyl ether, glycerin polyglycidyl ether, and polyglycerin polyglycidyl ether.

The polyfunctional isocyanate-based curing agent is not particularly limited as long as it is a compound having two or more isocyanate groups. Specific examples of the polyfunctional isocyanate-based curing agent include isophorone diisocyanate (IPDI), hexamethylene diisocyanate (HDI), tolylene diisocyanate (TDI), diphenylmethane diisocyanate (MDI), and those obtained by polymerizing or nurate these. Examples thereof include a mixture and a copolymer with another polymer.

The carbodiimide-based curing agent is not particularly limited as long as it is a compound having at least one carbodiimide group (-N = C = N-). As the carbodiimide-based curing agent, a polycarbodiimide compound having at least two or more carbodiimide groups is preferable.

The oxazoline-based curing agent is not particularly limited as long as it is a compound having an oxazoline skeleton. Specific examples of the oxazoline-based curing agent include the Epocross series manufactured by Nippon Shokubai Co., Ltd.

The curing agent may be composed of two or more kinds of compounds from the viewpoint of enhancing the adhesion between the barrier layer 3 by the second adhesive layer 5 and the heat-sealing resin layer 4.

The content of the curing agent in the resin composition forming the second adhesive layer 5 is preferably in the range of about 0.1 to 50% by mass, and more preferably in the range of about 0.1 to 30% by mass. It is preferably in the range of about 0.1 to 10% by mass, and more preferably in the range of about 0.1 to 10% by mass.

Further, the second adhesive layer 5 can be suitably formed by using an adhesive. Examples of the adhesive include a non-crystalline polyolefin resin (A) having a carboxyl group, a polyfunctional isocyanate compound (B), and a tertiary amine having no functional group that reacts with the polyfunctional isocyanate compound (B). C) is contained, and the polyfunctional isocyanate compound (B) is contained in a range in which the amount of isocyanate groups is 0.3 to 10 mol with respect to a total of 1 mol of carboxyl groups, with respect to a total of 1 mol of carboxyl groups. Examples thereof include those formed from an adhesive composition containing a tertiary amine (C) in a range of 1 to 10 mol. The adhesive contains a styrene-based thermoplastic elastomer (A), a tackifier (B), and a polyisocyanate (C), and contains a styrene-based thermoplastic elastomer (A) and a tackifier (adhesive). The styrene-based thermoplastic elastomer (A) is contained in an amount of 20 to 90% by weight and the pressure-sensitive adhesive (B) is contained in an amount of 10 to 80% by weight in a total of 100% by weight of the styrene-based thermoplastic elastomer (A). Has an active hydrogen derived from an amino group or a hydroxyl group of 0.003 to 0.04 mmol / g, and has the tackifier (B) with respect to 1 mol of the active hydrogen derived from the styrene-based thermoplastic elastomer (A). The active hydrogen derived from the functional group of) is 0 to 15 mol, and the polyisocyanate (C) is the active hydrogen derived from the styrene-based thermoplastic elastomer (A) and the active hydrogen derived from the tackifier (B). Examples thereof include those formed by an adhesive composition composed of those containing an isocyanate group in a range of 3 to 150 mol with respect to 1 mol in total.

The thickness of the second adhesive layer 5 is not particularly limited as long as it functions as an adhesive layer, but when the adhesive exemplified in the adhesive layer 2 is used, it is preferably about 2 to 10 μm, more preferably. The size is about 2 to 5 μm. Further, when the resin exemplified in the heat-sealing resin layer 4 is used, it is preferably about 2 to 50 μm, more preferably about 10 to 40 μm. Further, in the case of a cured product of the acid-modified polyolefin and the curing agent, it is preferably about 30 μm or less, more preferably about 0.1 to 20 μm, and further preferably about 0.5 to 5 μm. In the case of the adhesive layer formed by the above-mentioned adhesive composition, the thickness after drying and curing is about 1 to ^{30 g / m 2.} When the second adhesive layer 5 is a cured product of a resin composition containing an acid-modified polyolefin and a curing agent, the second adhesive layer 5 is formed by applying the resin composition and curing it by heating or the like. be able to.

[Surface coating layer 6]
In the packaging material for a battery of the present invention, for the purpose of improving designability, electrolytic solution resistance, scratch resistance, moldability, etc., if necessary, above the base material layer 1 (barrier layer of the base material layer 1). A surface coating layer 6 may be provided on the side opposite to 3), if necessary. The surface coating layer 6 is a layer located on the outermost layer when the battery is assembled.

The surface coating layer 6 can be formed of, for example, polyvinylidene chloride, polyester resin, urethane resin, acrylic resin, epoxy resin, or the like. Among these, the surface coating layer 6 is preferably formed of a two-component curable resin. Examples of the two-component curable resin forming the surface coating layer 6 include a two-component curable urethane resin, a two-component curable polyester resin, and a two-component curable epoxy resin. Further, an additive may be blended in the surface coating layer 6.

Examples of the additive include fine particles having a particle size of about 0.5 nm to 5 μm. The material of the additive is not particularly limited, and examples thereof include metals, metal oxides, inorganic substances, and organic substances. The shape of the additive is also not particularly limited, and examples thereof include a spherical shape, a fibrous shape, a plate shape, an amorphous shape, and a balloon shape. As additives, specifically, talc, silica, graphite, kaolin, montmoriloid, montmorillonite, synthetic mica, hydrotalcite, silica gel, zeolite, aluminum hydroxide, magnesium hydroxide, zinc oxide, magnesium oxide, aluminum oxide, Neodium oxide, antimony oxide, titanium oxide, cerium oxide, calcium sulfate, barium sulfate, calcium carbonate, calcium silicate, lithium carbonate, calcium benzoate, calcium oxalate, magnesium stearate, alumina, carbon black, carbon nanotubes, high Melting point nylon, crosslinked acrylic, crosslinked styrene, crosslinked polyethylene, benzoguanamine, gold, aluminum, copper, nickel and the like can be mentioned. These additives may be used alone or in combination of two or more. Among these additives, silica, barium sulfate, and titanium oxide are preferable from the viewpoint of dispersion stability and cost. Further, the additive may be subjected to various surface treatments such as an insulation treatment and a highly dispersible treatment on the surface.

The method for forming the surface coating layer 6 is not particularly limited, and examples thereof include a method of applying a two-component curable resin for forming the surface coating layer 6 on one surface of the base material layer 1. When the additive is blended, the additive may be added to the two-component curable resin, mixed, and then applied.

The thickness of the surface coating layer 6 is not particularly limited as long as it exhibits the above-mentioned functions as the surface coating layer 6, and examples thereof include about 0.5 to 10 μm, preferably about 1 to 5 μm.

3. 3. Method for Producing Battery Packaging Material The method for producing the battery packaging material of the present invention is not particularly limited as long as a laminate in which each layer having a predetermined composition is laminated can be obtained. That is, in the method for producing a packaging material for a battery of the present invention, at least a step of laminating a base material layer, an adhesive layer, a barrier layer, and a heat-sealing resin layer in this order to obtain a laminate. A method for producing a packaging material for a battery, wherein the base material layer includes a first adhesive layer between a polyester film layer and a polyamide film layer, and the adhesive layer and the first adhesive layer are Examples thereof include methods in which the hardness measured by the nanoindentation method is 50 MPa or less.

An example of the method for producing the packaging material for a battery of the present invention is as follows. First, a laminate in which the base material layer 1, the adhesive layer 2, and the barrier layer 3 are laminated in this order (hereinafter, may be referred to as “laminate A”) is formed. Specifically, the laminated body A is formed by applying an adhesive used for forming the adhesive layer 2 on the base material layer 1 or, if necessary, on the barrier layer 3 whose surface has been chemically converted, by a gravure coating method. It can be carried out by a dry laminating method in which the barrier layer 3 or the base material layer 1 is laminated and the adhesive layer 2 is cured after being coated and dried by a coating method such as a roll coating method.

Next, the second adhesive layer 5 and the heat-sealing resin layer 4 are laminated on the barrier layer 3 of the laminated body A in this order. For example, (1) a method of laminating the second adhesive layer 5 and the heat-sealing resin layer 4 on the barrier layer 3 of the laminated body A by co-extruding (co-extrusion laminating method), (2) separately. 2 A method of forming a laminated body in which an adhesive layer 5 and a heat-sealing resin layer 4 are laminated and laminating this on the barrier layer 3 of the laminated body A by a thermal laminating method. (3) Barrier layer 3 of the laminated body A An adhesive for forming the second adhesive layer 5 was coated on the adhesive by an extrusion method or a solution coating, dried at a high temperature, and then laminated by a baking method or the like, and a sheet-like film was formed on the second adhesive layer 5 in advance. A method of laminating the heat-sealing resin layer 4 by a thermal laminating method, (4) melting between the barrier layer 3 of the laminated body A and the heat-sealing resin layer 4 which has been formed into a sheet in advance. Examples thereof include a method of laminating the laminate A and the heat-sealing resin layer 4 via the second adhesive layer 5 while pouring the second adhesive layer 5 (sandwich laminating method).

When the surface coating layer 6 is provided, the surface coating layer 6 is laminated on the surface of the base material layer 1 opposite to the barrier layer 3. The surface coating layer 6 can be formed, for example, by applying the above resin forming the surface coating layer 6 to the surface of the base material layer 1. The order of the step of laminating the barrier layer 3 on the surface of the base material layer 1 and the step of laminating the surface coating layer 6 on the surface of the base material layer 1 is not particularly limited. For example, after forming the surface coating layer 6 on the surface of the base material layer 1, the barrier layer 3 may be formed on the surface of the base material layer 1 opposite to the surface coating layer 6.

As described above, the surface coating layer 6 provided as needed / the base material layer 1 / the adhesive layer 2 / the barrier layer 3 whose surface is chemically treated as needed / the second adhesive provided as needed. A laminate composed of layer 5 / heat-sealing resin layer 4 is formed, but in order to strengthen the adhesiveness of the adhesive layer 2 or the second adhesive layer 5, a hot roll contact type, a hot air type, etc. It may be subjected to heat treatment such as near infrared type or far infrared type. Examples of the conditions for such heat treatment include about 1 to 5 minutes at about 150 to 250 ° C.

In the packaging material for batteries of the present invention, each layer constituting the laminated body improves or stabilizes film forming property, laminating process, suitability for secondary processing (pouching, embossing) of the final product, etc., as necessary. Therefore, surface activation treatments such as corona treatment, blast treatment, oxidation treatment, and ozone treatment may be performed.

4. Applications of Battery Packaging Materials The battery packaging materials of the present invention are used in packaging for sealing and accommodating battery elements such as positive electrodes, negative electrodes, and electrolytes. That is, a battery element having at least a positive electrode, a negative electrode, and an electrolyte can be housed in a package formed of the battery packaging material of the present invention to form a battery.

Specifically, a battery element having at least a positive electrode, a negative electrode, and an electrolyte is used in the battery packaging material of the present invention, with metal terminals connected to each of the positive electrode and the negative electrode projecting outward. A battery is formed by covering the peripheral edge of an element so that a flange portion (a region where the heat-sealing resin layers come into contact with each other) can be formed, and heat-sealing and sealing the heat-sealing resin layers of the flange portion. Batteries using packaging materials for use are provided. When the battery element is housed in the package formed of the battery packaging material of the present invention, the heat-sealing resin portion of the battery packaging material of the present invention is on the inside (the surface in contact with the battery element). To form a package.

The packaging material for a battery of the present invention may be used for either a primary battery or a secondary battery, but is preferably a secondary battery. The type of secondary battery to which the packaging material for a battery of the present invention is applied is not particularly limited, and for example, a lithium ion battery, a lithium ion polymer battery, a lead storage battery, a nickel / hydrogen storage battery, a nickel / cadmium storage battery, a nickel / Examples thereof include iron storage batteries, nickel / zinc storage batteries, silver oxide / zinc storage batteries, metal air batteries, polyvalent cation batteries, capacitors, and capacitors. Among these secondary batteries, lithium ion batteries and lithium ion polymer batteries can be mentioned as suitable application targets of the battery packaging material of the present invention.

Hereinafter, the present invention will be described in detail with reference to Examples and Comparative Examples. However, the present invention is not limited to the examples.

<Manufacturing of packaging materials for batteries>
Example 1
As a base material layer, a polyethylene terephthalate film and a nylon film were laminated by coextrusion, and a biaxially stretched laminated film was prepared. In the laminated film, a modified thermoplastic resin graft-modified with an unsaturated carboxylic acid derivative component is contained between the (biaxially stretched) polyethylene terephthalate film (thickness 5 μm) and the (biaxially stretched) nylon film (thickness 20 μm). It is bonded by a first adhesive layer (thickness 1 μm) using the resin composition to be used. Next, a barrier layer made of an aluminum foil (JIS H4160: 1994 A8021HO, thickness 40 μm) having a chemical conversion treatment on both sides and having an acid resistant film is formed on the surface of the (biaxially stretched) nylon film side by a dry lamination method. Was laminated by. Specifically, a two-component polyurethane adhesive (polyol compound and aromatic isocyanate compound) is applied to one surface of an aluminum foil provided with an acid-resistant film, and an adhesive layer (thickness 3 μm) is applied on the barrier layer. Was formed. Next, the adhesive layer on the barrier layer provided with the acid-resistant film and the (biaxially stretched) nylon film side of the base material layer were laminated, and then an aging treatment was carried out at 40 ° C. for 24 hours (2). A laminate of a (axially stretched) polyethylene terephthalate film / first adhesive layer / (biaxially stretched) nylon film / adhesive layer / barrier layer was prepared. The hardness of the (biaxially stretched) polyethylene terephthalate film, the first adhesive layer, the (biaxially stretched) nylon film, and the adhesive layer is as shown in Table 2, respectively. The aluminum foil used as the barrier layer has an acid-resistant film containing cerium oxide and phosphate. The analysis of the acid-resistant film was performed as follows. First, the barrier layer and the second adhesive layer described later were peeled off. At this time, it was physically peeled off without using water, an organic solvent, an aqueous solution of an acid or an alkali, or the like. After peeling between the barrier layer and the second adhesive layer, the second adhesive layer remained on the surface of the barrier layer, so the remaining second adhesive layer was removed by etching with Ar-GCIB. The surface of the barrier layer thus obtained was analyzed for an acid-resistant film by using a time-of-flight secondary ion mass spectrometry method. As a result, the acid-resistant coating, Ce ⁺ or PO ₃ ^- 2 ion, such as have been detected. The details of the measuring device and the measuring conditions of the time-of-flight secondary ion mass spectrometry are as follows.

Measuring device: Time-of-flight secondary ion mass spectrometer TOF. SIMS5
Measurement conditions Primary ion: Double-charged ion of bismuth cluster (Bi ₃ ⁺⁺ )
Primary ion acceleration voltage: 30 kV
Mass range (m / z): 0 to 1500
Measurement range: 100 μm x 100 μm
Number of scans: 16 scan / cycle
Number of pixels (1 side): 256 pixel
Etching Ions: Ar Gas Cluster Ion Beam (Ar-GCIB)
Etching ion acceleration voltage: 5.0 kV

Next, a non-crystalline polyolefin resin having a carboxyl group and an adhesive containing a polyfunctional isocyanate compound were applied and dried at 100 ° C., and the barrier layer side of the obtained laminate and a non-stretched random polypropylene film ( The second adhesive layer / heat-sealing resin layer was laminated on the metal foil by passing between two rolls having a thickness of 80 μm) set at 60 ° C. and adhering them. Next, the obtained laminate was cured (aged) at 40 ° C. for 1 day and at 40 ° C. for 5 days to obtain a (biaxially stretched) polyethylene terephthalate film (5 μm) / first adhesive layer (1 μm) / (. Biaxially stretched) Nylon film (20 μm) / adhesive layer (3 μm) / barrier layer (40 μm) / second adhesive layer (2 μm) / unstretched random polypropylene film (80 μm) are laminated in this order as a packaging material for batteries. Obtained. Table 1 shows the layer structure of the battery packaging material.

Comparative Example 1
In the same manner as in Example 1, a laminated film in which a (biaxially stretched) polyethylene terephthalate film (thickness 5 μm) and a (biaxially stretched) nylon film (thickness 20 μm) were laminated by coextrusion was prepared as a base material layer. .. Next, a barrier layer made of an aluminum foil (JIS H4160: 1994 A8021HO, thickness 40 μm) having a chemical conversion treatment on both sides and having an acid resistant film is formed on the surface of the (biaxially stretched) nylon film side by a dry lamination method. Was laminated by. Specifically, a urethane-based adhesive was applied to one surface of an aluminum foil provided with an acid-resistant film to form an adhesive layer (thickness 3 μm) on the barrier layer. Next, the adhesive layer on the barrier layer and the (biaxially stretched) nylon film side of the base material layer are laminated, and then an aging treatment is carried out at 40 ° C. for 24 hours to obtain a (biaxially stretched) polyethylene terephthalate film. A laminate of / first adhesive layer / (biaxially stretched) nylon film / adhesive layer / barrier layer was prepared. The hardness of the (biaxially stretched) polyethylene terephthalate film, the first adhesive layer, the (biaxially stretched) nylon film, and the adhesive layer is as shown in Table 2, respectively. The aluminum foil used as the barrier layer has an acid-resistant film containing chromium oxide and phosphate. The analysis of the acid-resistant film on the barrier layer was carried out by using the time-of-flight secondary ion mass spectrometry method as in Example 1. As a result, the acid-resistant film, Cr ⁺ or PO ₃ ^- 2 ion, such as have been detected. Next, maleic anhydride-modified polypropylene (thickness 40 μm) as the second adhesive layer and random polypropylene (thickness 40 μm) as the heat-sealing resin layer are co-extruded onto the barrier layer of the obtained laminate. As a result, the second adhesive layer / heat-sealing resin layer was laminated on the barrier layer. Next, the obtained laminate was aged in a temperature environment of 80 ° C. for 24 hours, and finally heated at 190 ° C. for 2 minutes to obtain a (biaxially stretched) polyethylene terephthalate film (5 μm) / first adhesive layer (1 μm). ) / (Biaxially stretched) nylon film (20 μm) / adhesive layer (3 μm) / barrier layer (40 μm) / maleic anhydride-modified polypropylene (40 μm) / random polypropylene and (40 μm) laminated in this order for battery packaging Obtained the material. Table 1 shows the layer structure of the battery packaging material.

Example 2 and Comparative Example 2-3
As the base material layer, a laminated film in which a biaxially stretched polyethylene terephthalate film (thickness 12 μm) and a biaxially stretched nylon film (thickness 15 μm) were laminated by a dry laminating method was prepared. In the laminated film, the biaxially stretched polyethylene terephthalate film and the biaxially stretched nylon film are adhered with a urethane adhesive using a polyol and an isocyanate-based curing agent. Next, a barrier layer made of aluminum foil (JIS H4160: 1994 A8021HO, thickness 40 μm) having undergone chemical conversion treatment on both sides was laminated on the surface of the biaxially stretched nylon film side by a dry laminating method. Specifically, a two-component urethane adhesive (polyol compound and aromatic isocyanate compound) was applied to one surface of the aluminum foil to form an adhesive layer (thickness 3 μm) on the barrier layer. Next, the adhesive layer on the barrier layer and the biaxially stretched nylon film side of the base material layer were laminated, and then an aging treatment was carried out at 40 ° C. for 24 hours to obtain a biaxially stretched polyethylene terephthalate film / first adhesive. A laminated body of a layer / biaxially stretched nylon film / adhesive layer / barrier layer was prepared. The hardness of the biaxially stretched polyethylene terephthalate film, the first adhesive layer, the biaxially stretched nylon film, and the adhesive layer are as shown in Table 2, respectively. The aluminum foil used as the barrier layer has an acid-resistant film containing chromium oxide and phosphate. The analysis of the acid-resistant film on the barrier layer was carried out by using the time-of-flight secondary ion mass spectrometry method as in Example 1. As a result, the acid-resistant film, Cr ⁺ or PO ₃ ^- 2 ion, such as have been detected.

Next, maleic anhydride-modified polypropylene (thickness 40 μm) as the second adhesive layer and random polypropylene (thickness 40 μm) as the heat-sealing resin layer are co-extruded onto the barrier layer of the obtained laminate. As a result, the second adhesive layer / heat-sealing resin layer was laminated on the barrier layer. Next, the obtained laminate was aged in a temperature environment of 80 ° C. for 24 hours, and finally heated at 190 ° C. for 2 minutes to obtain a biaxially stretched polyethylene terephthalate film (12 μm) / first adhesive layer (3 μm) /. A packaging material for a battery was obtained in which biaxially stretched nylon film (15 μm) / adhesive layer (3 μm) / barrier layer (40 μm) / maleic anhydride-modified polypropylene (40 μm) / random polypropylene and (40 μm) were laminated in this order. .. Table 1 shows the layer structure of the battery packaging material.

Example 3
In Comparative Example 2 described above, after laminating the adhesive layer on the barrier layer and the biaxially stretched nylon film side of the base material layer, instead of the aging treatment of "40 ° C. for 24 hours", "12 at 40 ° C." Biaxially stretched polyethylene terephthalate film (12 μm) / first adhesive layer (3 μm) / biaxially stretched nylon film (15 μm) / adhesive layer in the same manner as in Comparative Example 2 except that the aging treatment of “time” was performed. A packaging material for a battery was obtained in which (3 μm) / barrier layer (40 μm) / maleic anhydride-modified polypropylene (40 μm) / random polypropylene and (40 μm) were laminated in this order. Table 1 shows the layer structure of the battery packaging material. The hardness of the biaxially stretched polyethylene terephthalate film, the first adhesive layer, the biaxially stretched nylon film, and the adhesive layer are as shown in Table 2, respectively.

Example 4
In Example 1, a stainless steel foil (SUS304, thickness 20 μm) having an acid-resistant film obtained by subjecting both sides to a chemical conversion treatment (the same chemical conversion treatment as in Example 1) was used as the barrier layer. In the same manner as in 1, (biaxially stretched) polypropylene terephthalate film (5 μm) / first adhesive layer (1 μm) / (biaxially stretched) nylon film (20 μm) / adhesive layer (3 μm) / barrier layer (20 μm) / A packaging material for a battery was obtained in which a second adhesive layer (2 μm) / unstretched random polypropylene film (80 μm) was laminated in this order. Table 1 shows the layer structure of the battery packaging material. The hardness of the (biaxially stretched) polyethylene terephthalate film, the first adhesive layer, the (biaxially stretched) nylon film, and the adhesive layer is as shown in Table 2, respectively.

Example 5
In Example 3, except that a stainless steel foil (SUS304, thickness 20 μm) having an acid-resistant film obtained by performing chemical conversion treatment on both sides (similar chemical conversion treatment as in Example 1) was used as the barrier layer. Biaxially stretched polypropylene terephthalate film (12 μm) / first adhesive layer (3 μm) / biaxially stretched nylon film (15 μm) / adhesive layer (3 μm) / barrier layer (20 μm) / maleic anhydride modification in the same manner as in 3. A packaging material for a battery was obtained in which polypropylene (40 μm) / random polypropylene and (40 μm) were laminated in this order. Table 1 shows the layer structure of the battery packaging material. The hardness of the biaxially stretched polyethylene terephthalate film, the first adhesive layer, the biaxially stretched nylon film, and the adhesive layer are as shown in Table 2, respectively.

Comparative Example 4
In Comparative Example 2, a stainless steel foil (SUS304, thickness 20 μm) having an acid-resistant film obtained by subjecting both sides to a chemical conversion treatment (the same chemical conversion treatment as in Example 1) was used as the barrier layer. Biaxially stretched polypropylene terephthalate film (12 μm) / first adhesive layer (3 μm) / biaxially stretched nylon film (15 μm) / adhesive layer (3 μm) / barrier layer (20 μm) / maleic anhydride modification in the same manner as in 2. A packaging material for a battery was obtained in which polypropylene (40 μm) / random polypropylene and (40 μm) were laminated in this order. Table 1 shows the layer structure of the battery packaging material. The hardness of the biaxially stretched polyethylene terephthalate film, the first adhesive layer, the biaxially stretched nylon film, and the adhesive layer are as shown in Table 2, respectively.

In Table 1, the numerical value in parentheses in the layer structure means the thickness (μm). Further, PET is a biaxially stretched polypropylene terephthalate film, Ny is a biaxially stretched nylon film, AD is a first adhesive layer formed by coextrusion, and DL is a first adhesive layer formed by a dry laminating method (Example 2). , 3, 5, Comparative Example 2-4), Adhesive layer (Examples 1-5, Comparative Example 1-4), or Second adhesive layer (Examples 1 and 4), ALM is aluminum foil, SUS is stainless steel Steel foil, CPP is a heat-sealing resin layer formed of unstretched polypropylene, PPa is a second adhesive layer formed of maleic anhydride-modified polypropylene (Examples 2, 3 and 5, Comparative Examples 1-4), PP means a heat-sealing resin layer formed of random polypropylene.

<Measurement of hardness of each layer>
As an apparatus, a nanoindenter ((“TriboIndenter TI950” manufactured by HYSITRON)) was used. As an indenter of the nanoindenter, a Berkovich indenter (triangular pyramid) was used. First, relative humidity was 50%, 23. In a ° C environment, the indenter is applied to the surface of the adhesive layer of the packaging material for batteries (the surface where the adhesive layer is exposed and perpendicular to the stacking direction of each layer), and the surface is applied for 10 seconds. The indenter was pushed into the adhesive layer from the top to a load of 40 μN, held in that state for 5 seconds, and then unloaded over 10 seconds. Maximum load P _max (μN) and contact projection area A (μm) at maximum depth. ^The indentation hardness (MPa) was calculated by P _max / A using 2). The hardness of the first adhesive layer was measured in the same manner as the adhesive layer except that the load was 10 μN. The hardness of the biaxially stretched polyethylene terephthalate film and the biaxially stretched nylon film were measured in the same manner in the same manner except that the load was 100 μN under the above measurement conditions. The average value of N = 5 was used. The hardness of each is shown in Table 2. The surface on which the indenter is pushed is cut in the thickness direction so as to pass through the center of the packaging material for batteries, and is adhered. This is a portion where the cross section of the agent layer or the like is exposed. Cutting was performed using a commercially available rotary microtome or the like.

<Evaluation of moldability>
Each of the battery packaging materials obtained above was cut into a rectangle having a length (MD) of 90 mm and a width (TD) of 150 mm to prepare a test sample. The MD of the packaging material for batteries corresponds to the rolling direction (RD) of the aluminum alloy foil, and the TD of the packaging material for batteries corresponds to the TD of the aluminum alloy foil. Comparison of this sample with a rectangular molding die having a length of 31.6 mm (MD) and a width of 54.5 mm (TD) (female mold, surface is JIS B 0659-1: 2002 Annex 1 (reference)). The maximum height roughness (nominal value of Rz) specified in Table 2 of the surface roughness standard piece for use is 3.2 μm. Corner R2.0 mm, ridge line R1.0 mm) and the corresponding molding die. (For male type and surface, JIS B 0659-1: 2002 Annex 1 (Reference) The maximum height roughness (nominal value of Rz) specified in Table 2 of the comparative surface roughness standard piece is 1.6 μm. There are 10 pieces each, using a corner R2.0 mm and a ridge line R1.0 mm), changing the molding depth in 0.5 mm increments from a molding depth of 0.5 mm at a pressing pressure (surface pressure) of 0.25 MPa. Cold molding (pull-in one-step molding) was performed on the sample. At this time, the test sample was placed on the female mold so that the heat-sealing resin layer side was located on the male mold side, and molding was performed. The clearance between the male type and the female type was set to 0.3 mm. The cold-formed sample was exposed to light with a penlight in a dark room, and it was confirmed whether or not pinholes or cracks were generated in the aluminum foil due to the transmission of light. The deepest molding depth where pinholes and cracks do not occur in all 10 samples on the aluminum foil is Amm, and the number of samples where pinholes and the like occur at the shallowest molding depth where pinholes and the like occur on the aluminum foil is B. The value calculated by the following formula was rounded to the second digit after the decimal point to obtain the limit molding depth of the packaging material for batteries. The results are shown in Table 2.
Limit molding depth = Amm + (0.5mm / 10 pieces) x (10 pieces-B pieces)

In Table 2, PET means a biaxially stretched polyethylene terephthalate film, and Ny means a biaxially stretched nylon film.

As is clear from the results shown in Table 2, it is composed of a laminate having a base material layer, an adhesive layer, a barrier layer, and a heat-sealing resin layer in this order, and the base material layer is a polyester film layer. Example 1-3 in which a first adhesive layer is provided between the polyamide film layer and the adhesive layer and the first adhesive layer have hardnesses of 50 MPa or less as measured by the nanoindentation method. The packaging material for batteries (using aluminum foil as the barrier layer) has a molding depth of 7.3 mm or more, and Examples 4 and 5 (using stainless steel foil as the barrier layer) have a molding depth of 3.2 mm. As described above, the moldability was excellent. On the other hand, although the laminated structure is common to that of Example 1-5, at least one of the hardnesses of the adhesive layer and the first adhesive layer measured by the nanoindentation method exceeds 50 MPa in Comparative Example 1. The battery packaging material of -4 was inferior in moldability as compared with Example 1-5. That is, when Example 1 using an aluminum foil as a barrier layer and Comparative Example 1 are compared, Example 1 is 0.5 mm superior in moldability to Comparative Example 1, and when Examples 2 and 3 are compared with Comparative Example 2. Examples 2 and 3 are 0.6 mm better in moldability than Comparative Example 3, and when comparing Examples 2 and 3 and Comparative Example 3, Examples 2 and 3 are 0.3 mm better in moldability than Comparative Example 3. Was there. Further, when Examples 4 and 5 using stainless steel foil as the barrier layer and Comparative Example 4 were compared, Examples 4 and 5 were superior to Comparative Example 4 in moldability by 0.4 to 0.8 mm.

1 Base material layer 11 Polyester film layer 12 Polyamide film layer 13 First adhesive layer 2 Adhesive layer 3 Barrier layer 4 Heat-sealing resin layer 5 Second adhesive layer 6 Surface coating layer 10 Battery packaging material

Claims (13)

It is composed of a laminate having at least a base material layer, an adhesive layer, a barrier layer, and a heat-sealing resin layer in this order.
In the base material layer, a first adhesive layer is provided between the polyester film layer and the polyamide film layer.
The adhesive layer and the first adhesive layer are battery packaging materials having a hardness of 50 MPa or less as measured by the nanoindentation method, respectively. The packaging material for a battery according to claim 1, wherein the ratio of the thickness of the polyester film layer to the thickness of the polyamide film layer is in the range of 1: 1 to 1: 5. The packaging material for a battery according to claim 1 or 2, wherein the thickness of the adhesive layer is 5 μm or less. The packaging material for a battery according to any one of claims 1 to 3, wherein the thickness of the first adhesive layer is 3 μm or less. The adhesive layer is formed of a polyurethane-based adhesive, a polyacrylic-based adhesive, a modified polypropylene-based adhesive, an adhesive containing a silane-based coupling agent, or an adhesive containing a titanate-based coupling agent. Item 4. The packaging material for a battery according to any one of Items 1 to 4. The first adhesive layer according to any one of claims 1 to 5, wherein the first adhesive layer is formed of a resin composition containing a modified thermoplastic resin graft-modified with an unsaturated carboxylic acid or an unsaturated carboxylic acid derivative component. Battery packaging material. The packaging material for a battery according to any one of claims 1 to 6, wherein an acid-resistant film is provided on at least the surface of the barrier layer on the side of the heat-sealing resin layer. The packaging material for a battery according to claim 7, wherein the acid-resistant film contains at least one element selected from the group consisting of phosphorus, chromium and cerium. The packaging material for a battery according to claim 7, wherein the acid-resistant film contains at least one selected from the group consisting of phosphates, chromates, fluorides, and triazinethiol compounds. The packaging material for a battery according to claim 7, wherein the acid-resistant film contains a cerium compound. The battery packaging material according to claim 7, wherein when the acid-resistant film is analyzed using a time-of-flight secondary ion mass spectrometry method, ^{a peak derived from at least one of Ce +} and Cr ^{+ is detected.} .. A battery in which a battery element including at least a positive electrode, a negative electrode, and an electrolyte is housed in a package formed of the battery packaging material according to any one of claims 1 to 11. A method for producing a packaging material for a battery, which comprises a step of laminating at least a base material layer, an adhesive layer, a barrier layer, and a heat-sealing resin layer in this order to obtain a laminate.
The base material layer includes a first adhesive layer between the polyester film layer and the polyamide film layer.
A method for producing a packaging material for a battery, wherein the adhesive layer and the first adhesive layer each have a hardness of 50 MPa or less as measured by a nanoindentation method.

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