JP6710897B2 - Battery packaging material - Google Patents

Description

TECHNICAL FIELD The present invention relates to a battery packaging material having excellent printing characteristics of ink on the surface of a base material layer side.

Conventionally, various types of batteries have been developed, but in all batteries, a packaging material is an indispensable member for sealing battery elements such as electrodes and electrolytes. Conventionally, metal packaging materials have been widely used for battery packaging, but in recent years, as electric vehicles, hybrid electric vehicles, personal computers, cameras, mobile phones, etc. have become more sophisticated, batteries are required to have various shapes. At the same time, it is required to be thinner and lighter. However, the metal battery packaging materials that have been widely used in the past have the drawbacks that it is difficult to follow the diversification of shapes and there is a limit to weight reduction.

Therefore, as a battery packaging material that can be easily processed into various shapes and that can be made thinner and lighter, we propose a film-like laminate in which the base material layer/adhesive layer/metal layer/sealant layer are sequentially laminated. (For example, see Patent Document 1). Such a film-shaped battery packaging material is formed so that the battery element can be sealed by making the sealant layers face each other and heat-sealing the peripheral portions by heat sealing.

In various packaging materials formed by the above laminated body, ink is printed on the surface of the base material layer side to form barcodes, patterns, characters, etc., on the base material layer on the printed side. A method of printing on a packaging material (generally called reverse printing) by a method of laminating an adhesive and a metal foil is widely adopted. However, when such a printed surface is present between the base material layer and the metal layer, the adhesion between the base material layer and the metal layer is deteriorated, and delamination easily occurs between the layers. In particular, since the battery to which the battery packaging material is applied is required to have high safety, such a method of printing by back printing is shunned in the battery packaging material. Therefore, conventionally, when a print such as a bar code is formed on a battery packaging material, a method in which a seal having a print formed thereon is attached to the surface of the base material layer side is generally adopted.

However, if a seal with a print is attached to the surface of the base material layer side, the thickness and weight of the battery packaging material increase. Therefore, in view of the recent trend toward thinner and lighter packaging materials for batteries, a method of printing by directly printing ink on the surface of the packaging material for batteries on the side of the base material layer has been studied.

Pad printing (also referred to as tampo printing) is known as a method for printing by printing ink directly on the surface of the base material layer side of the battery packaging material. Pad printing is the following printing method. First, ink is poured into the concave portion of the flat plate in which the pattern to be printed is etched. Next, the silicon pad is pressed against the concave portion to transfer the ink to the silicon pad. Next, the ink transferred to the surface of the silicon pad is transferred to the print target to form a print on the print target. In such pad printing, since the ink is transferred to the print target using an elastic silicon pad, it is easy to print on the surface of the battery packaging material after molding, and the battery element can be used as a battery packaging material. It has the advantage that the battery can be printed after sealing.

By the way, in a packaging material for a battery, a space for accommodating the battery element is formed by molding with a mold when enclosing the battery element. At the time of this molding, the battery packaging material is stretched, which causes a problem that cracks and pinholes are easily generated in the metal layer in the flange portion of the mold. In order to solve such a problem, by coating a lubricant on the surface of the base material layer of the battery packaging material, or by transferring the lubricant bleeding out to the sealant layer surface to the base material layer surface in a roll state, A method for increasing the slipperiness of the base material layer is known. By adopting such a method, at the time of molding, the battery packaging material is easily drawn into the mold, and cracks and pinholes in the battery packaging material can be suppressed. In particular, in order to reduce the thickness and weight of the battery packaging material in recent years, it is desirable to add a lubricant to the surface of the battery packaging material on the side of the base material layer to enhance the slipperiness of the battery packaging material.

JP 2008-287971 A

However, as a result of the study by the present inventors, when a lubricant is present on the surface of the base material layer to enhance the moldability of the battery packaging material, the ink is repelled on the surface of the base material layer. , It became difficult to fix the ink, and it became clear that a dropout portion where the ink was not formed might occur. In particular, it has been clarified that the printability tends to be insufficient when printed by pad printing.
Under such circumstances, the main object of the present invention is to provide a battery packaging material having excellent ink printing characteristics on the surface of the base material layer. Another object of the present invention is to provide a method for producing the battery packaging material, and a battery using the battery packaging material.

The present inventors have diligently studied to solve the above problems. As a result, at least in the packaging material for a battery composed of a laminate in which a base material layer, a metal layer, and a sealant layer are sequentially laminated, the base material layer side surface (the surface opposite to the sealant layer) contacts. It was found that the printing characteristics of the ink on the surface of the base material layer side can be effectively enhanced by setting the angle to 80° or less. Furthermore, the present inventors have found that by performing corona treatment on the surface of the base material layer side, the contact angle of the surface of the base material layer side can be set to 80° or less. The present invention has been completed by further studies based on these findings.

That is, the present invention provides the inventions of the following modes.
Item 1. At least a base material layer, a metal layer, and a sealant layer consisting of a laminated body sequentially laminated,
A packaging material for a battery, wherein the contact angle of the surface of the base material layer side is 80° or less.
Item 2. Item 2. The battery packaging material according to Item 1, which is used by printing ink on at least a part of the surface of the base material layer side.
Item 3. Item 3. The battery packaging material according to Item 1 or 2, wherein ink is printed on at least a part of the surface of the base material layer side.
Item 4. Item 4. The battery packaging material according to any one of Items 1 to 3, wherein the surface of the base material layer side is corona-treated.
Item 5. Item 5. The battery packaging material according to any one of Items 1 to 4, wherein an adhesive layer is laminated between the base material layer and the metal layer.
Item 6. Item 6. The battery packaging material according to any one of Items 1 to 5, wherein an adhesive layer is laminated between the metal layer and the sealant layer.
Item 7. Item 7. The battery packaging material according to any one of Items 1 to 6, wherein the metal layer is formed of an aluminum foil.
Item 8. Item 8. The battery packaging material according to any one of Items 1 to 7, wherein a lubricant is present on the surface of the base material layer side.
Item 9. A battery, wherein a battery element including at least a positive electrode, a negative electrode, and an electrolyte is housed in the battery packaging material according to any one of Items 1 to 8.
Item 10. At least a laminating step of laminating a base material layer, a metal layer, and a sealant layer to obtain a laminated body,
A corona treatment step of subjecting the surface on the side of the base material layer to corona treatment so that the contact angle of the surface on the side of the base material layer is 80° or less;
A method for producing a packaging material for a battery, comprising:
Item 11. Item 11. The method for producing a battery packaging material according to Item 10, comprising a step of printing ink on at least a part of the surface of the base material layer side after the corona treatment step.

ADVANTAGE OF THE INVENTION According to this invention, the packaging material for batteries excellent in the printing characteristic of the ink in the surface of the base material layer side can be provided. Further, according to the present invention, it is possible to provide a battery using the battery packaging material and a method for manufacturing the battery packaging material.

It is a figure which shows an example of the cross-section of the packaging material for batteries of this invention. It is a figure which shows an example of the cross-section of the packaging material for batteries of this invention. It is a figure which shows an example of the cross-section of the packaging material for batteries of this invention.

The battery packaging material of the present invention comprises at least a laminated body in which a base material layer, a metal layer, and a sealant layer are sequentially laminated, and the contact angle of the surface on the base material layer side is 80° or less. Is characterized by. Hereinafter, the battery packaging material of the present invention, the method for producing the battery packaging material, and the battery using the battery packaging material will be described in detail.

1. Laminated Structure of Battery Packaging Material As shown in FIG. 1, the battery packaging material of the present invention comprises a laminate in which at least a base material layer 1, a metal layer 3, and a sealant layer 4 are sequentially laminated. In the battery packaging material of the present invention, the base material layer 1 becomes the outermost layer (when the coating layer 6 is provided, the coating layer 6 becomes the outermost layer), and the sealant layer 4 becomes the innermost layer. That is, at the time of assembling the battery, the sealant layers 4 located at the periphery of the battery element are heat-sealed to seal the battery element, thereby sealing the battery element.

In the battery packaging material of the present invention, as shown in FIG. 1, an adhesive layer 2 is provided between the base material layer 1 and the metal layer 3 as needed for the purpose of enhancing the adhesiveness between them. Good. Further, as shown in FIG. 2, an adhesive layer 5 may be provided between the metal layer 3 and the sealant layer 4, if necessary, for the purpose of enhancing the adhesiveness between them. Further, as shown in FIG. 3, a coating layer 6 may be provided on the surface of the base material layer 1 (the surface opposite to the metal layer 3 side).

2. Composition of each layer forming the battery packaging material [base material layer 1]
In the battery packaging material of the present invention, the base material layer 1 is the outermost layer. However, when the coating layer 6 is provided, the coating layer 6 is located at the outermost layer.

The material forming the base material layer 1 is not particularly limited as long as it has an insulating property. Examples of the material forming the base material layer 1 include polyester, polyamide, epoxy resin, acrylic resin, fluororesin, polyurethane, silicon resin, phenol resin, polyetherimide, polyimide, and a mixture or copolymer thereof. Can be mentioned.

As the polyester, specifically, polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polybutylene naphthalate, polyethylene isophthalate, polycarbonate, a copolymerized polyester mainly composed of ethylene terephthalate repeating units, butylene terephthalate repeating units Copolymerized polyester and the like which is the main component can be mentioned. Further, the copolymerized polyester containing ethylene terephthalate as a main repeating unit includes, specifically, a copolymer polyester obtained by polymerizing ethylene terephthalate with ethylene isophthalate as a main repeating unit (hereinafter, polyethylene (terephthalate/isophthalate)). Abbreviated), polyethylene (terephthalate/isophthalate), polyethylene (terephthalate/adipate), polyethylene (terephthalate/sodium sulfoisophthalate), polyethylene (terephthalate/sodium isophthalate), polyethylene (terephthalate/phenyl-dicarboxylate) , Polyethylene (terephthalate/decanedicarboxylate) and the like. The copolymerized polyester mainly containing butylene terephthalate as a repeating unit is specifically a copolymer polyester that is polymerized with butylene terephthalate as a main repeating unit (hereinafter referred to as polybutylene (terephthalate/isophthalate)). Abbreviated), polybutylene (terephthalate/adipate), polybutylene (terephthalate/sebacate), polybutylene (terephthalate/decanedicarboxylate), 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 the advantage that whitening or the like is less likely to occur due to adhesion of the electrolytic solution, and is preferably used as a material for forming the base material layer 1.

Specific examples of the polyamide include nylon 6, nylon 66, nylon 610, nylon 12, nylon 46, an aliphatic polyamide such as a copolymer of nylon 6 and nylon 6,6; terephthalic acid and/or Nylon 6I, Nylon 6T, Nylon 6IT, Nylon 6I6T (I is isophthalic acid, T is terephthalic acid) hexamethylenediamine-isophthalic acid-terephthalic acid copolyamide, polymethacryl, etc. containing structural units derived from isophthalic acid A polyamide containing an aromatic compound such as silylene adipamide (MXD6); an alicyclic polyamide such as polyaminomethylcyclohexyl adipamide (PACM6); and a lactam component and an isocyanate component such as 4,4′-diphenylmethane-diisocyanate. Examples include polymerized polyamides, polyesteramide copolymers and polyetheresteramide copolymers that are copolymers of copolymerized polyamides and polyesters and polyalkylene ether glycols; and copolymers thereof. 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 base material layer 1 may be formed of a uniaxially or biaxially stretched resin film, or may be formed of an unstretched resin film. Among them, a uniaxially or biaxially stretched resin film, especially a biaxially stretched resin film has improved heat resistance due to oriented crystallization, and thus is suitably used as the base material layer 1. Further, the base material layer 1 may be formed by coating the above-mentioned materials on the metal layer 3.

Among these, the resin film forming the base material layer 1 is preferably nylon or polyester, more preferably biaxially stretched nylon, or biaxially stretched polyester, particularly preferably biaxially stretched nylon.

The base material layer 1 may be formed by laminating at least one of a resin film and a coating made of different materials in order to improve the pinhole resistance and the insulating property of the battery package. Specific examples include a multilayer structure in which a polyester film and a nylon film are laminated, a multilayer structure in which biaxially stretched polyester and biaxially stretched nylon are laminated, and the like. When the base material layer 1 has a multi-layer structure, the resin films may be adhered via an adhesive or may be directly laminated without an adhesive. In the case of adhering without using an adhesive, for example, a method of adhering in a hot melt state such as a co-extrusion method, a sand laminating method, or a thermal laminating method can be mentioned. When the adhesive is used for the adhesion, the adhesive to be used may be a two-component curing type adhesive or a one-component curing type adhesive. Further, the adhesion mechanism of the adhesive is not particularly limited, and may be any of chemical reaction type, solvent volatilization type, heat melting type, heat pressure type, electron beam curing type such as UV and EB. Polyester resin, polyether resin, polyurethane resin, epoxy resin, phenol resin resin, polyamide resin, polyolefin resin, polyvinyl acetate resin, cellulose resin, (meth)acrylic resin as a component of the adhesive. Examples thereof include resins, polyimide resins, amino resins, rubber, and silicon resins.

In the present invention, a lubricant is preferably attached to the surface of the base material layer 1 side from the viewpoint of improving the moldability of the battery packaging material. The lubricant is not particularly limited, but preferably an amide lubricant is used. Specific examples of the amide-based lubricant include saturated fatty acid amides, unsaturated fatty acid amides, substituted amides, methylolamides, saturated fatty acid bisamides, unsaturated fatty acid bisamides, and the like. Specific examples of the saturated fatty acid amide include lauric acid amide, palmitic acid amide, stearic acid amide, behenic acid amide, and hydroxystearic acid amide. Specific examples of unsaturated fatty acid amides include oleic acid amide and erucic acid amide. Specific examples of the substituted amide include N-oleylpaltimic acid amide, N-stearyl stearic acid amide, N-stearyl oleic acid amide, N-oleyl stearic acid amide, and N-stearyl erucic acid amide. Specific examples of methylolamide include methylolstearic acid amide. Specific examples of the saturated fatty acid bisamide include methylenebisstearic acid amide, ethylenebiscapric acid amide, ethylenebislauric acid amide, ethylenebisstearic acid amide, ethylenebishydroxystearic acid amide, ethylenebisbehenic acid amide, and hexamethylenebisstearic acid amide. Examples thereof include acid amide, hexamethylene bisbehenic acid amide, hexamethylene hydroxystearic acid amide, N,N′-distearyl adipic acid amide, and N,N′-distearyl sebacic acid amide. Specific examples of the unsaturated fatty acid bisamide include ethylene bisoleic acid amide, ethylene bis erucic acid amide, hexamethylene bis oleic acid amide, N,N′-dioleyl adipate amide, N,N′-dioleyl sebacic acid amide. And so on. Specific examples of the fatty acid ester amide include stearoamide ethyl stearate. Further, specific examples of the aromatic bisamide include m-xylylenebisstearic acid amide, m-xylylenebishydroxystearic acid amide, N,N'-cystearylisophthalic acid amide and the like. The lubricant may be used alone or in combination of two or more.

The thickness of the base material layer 1 is, for example, about 10 to 50 μm, preferably about 15 to 30 μm.

The battery packaging material of the present invention is characterized in that the contact angle of the surface on the base material layer 1 side (the outermost surface of the battery packaging material) is 80° or less. That is, when the base material layer 1 constitutes the outermost surface, the contact angle of the surface of the base material layer 1 is 80° or less. Further, when the coating layer 6 described later is provided outside the base material layer 1, the contact angle of the surface of the coating layer 6 is 80° or less. In the present invention, when the contact angle of the surface of the base material layer 1 side of the battery packaging material is 80° or less, the ink is not easily repelled on the surface of the base material layer 1 side, and the printability is excellent. In particular, when ink is printed by pad printing on a battery packaging material in which a lubricant is present on the surface of the base material layer 1 side to improve moldability, the ink is repelled on the surface of the base material layer 1 side, and printing is performed. Although a defect may occur, in the case of the battery packaging material of the present invention, even in such a case, the contact angle of the surface on the base material layer 1 side is 80° or less, so the ink is not easily repelled and the pad It is particularly suitable as a battery packaging material in which a print or the like is formed on the surface of the base material layer by printing.

In the battery packaging material of the present invention, the contact angle of the surface of the base material layer 1 side is not particularly limited as long as it is 80° or less, but from the viewpoint of improving printability, it is preferably 79° or less, It is preferably about 72° or less.

In the present invention, the contact angle of the battery packaging material is a value measured using LSE-A210 manufactured by Nick Co., Ltd., and the specific method is as described in Examples.

In the battery packaging material of the present invention, the contact angle of the surface of the base material layer 1 side can be preferably set to 80° or less by subjecting the surface of the base material layer 1 side to corona treatment. The corona treatment can be performed by irradiating the surface of the base material layer 1 side with corona discharge using a commercially available corona surface treatment device. The condition of the corona treatment is not particularly limited as long as the contact angle of the surface on the base material layer 1 side is 80° or less. For example, the contact angle can be set to 80° or less by treating the surface of the base material layer 1 side with an irradiation output of 1 Kw or more and a speed of 10 MT/min.

In the battery packaging material of the present invention, the ink can be suitably printed on at least a part of the surface of the base material layer 1 side. That is, in the present invention, in the battery packaging material in which the ink is printed on the surface of the base material layer 1 side, the printed ink (cured product of ink, dried material, etc.) is exposed on the surface of the base material layer 1 side. ing. The printed ink can form, for example, a print such as a barcode, a pattern, or a character. The ink used for printing is not particularly limited, and known ones can be used. For example, a photo-curable ink that is cured by irradiation with ultraviolet rays or an inkjet ink used in an inkjet printer or the like can be used. Can be used.

[Adhesive layer 2]
In the battery packaging material of the present invention, the adhesive layer 2 is a layer that is provided as necessary to bond the base material layer 1 and the metal layer 3 together.

The adhesive layer 2 is formed of an adhesive that can bond the base material layer 1 and the metal layer 3 together. The adhesive used for forming the adhesive layer 2 may be a two-component curable adhesive or a one-component curable adhesive. Further, the adhesion mechanism of the adhesive 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 hot pressing type and the like.

Specific examples of the resin component of the adhesive that can be used for forming the adhesive layer 2 include polyester-based resins such as polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polybutylene naphthalate, polyethylene isophthalate, polycarbonate, and copolyester. Resin: Polyether-based adhesive; Polyurethane-based adhesive; Epoxy-based resin; Phenolic resin-based resin; Nylon 6, Nylon 66, Nylon 12, polyamide-based resin such as copolyamide; Polyolefin, acid-modified polyolefin, metal-modified polyolefin, etc. Polyolefin resin; polyvinyl acetate resin; cellulose adhesive; (meth)acrylic resin; polyimide resin; urea resin, amino resin such as melamine resin; chloroprene rubber, nitrile rubber, rubber such as styrene-butadiene rubber Silicone resin; fluorinated ethylene propylene copolymer and the like. These adhesive components may be used alone or in combination of two or more. The combination mode of two or more adhesive components is not particularly limited, but for example, as the adhesive component, a mixed resin of polyamide and acid-modified polyolefin, a mixed resin of polyamide and metal-modified polyolefin, polyamide and polyester, Examples include mixed resins of polyester and acid-modified polyolefin, mixed resins of polyester and metal-modified polyolefin, and the like. Among these, extensibility, durability under high humidity conditions, an effect of suppressing change, and an effect of suppressing heat deterioration at the time of heat sealing are excellent, and a decrease in lamination strength between the base material layer 1 and the metal layer 3 is suppressed. From the viewpoint of effectively suppressing the occurrence of delamination, a polyurethane-based two-component curable adhesive; polyamide, polyester, or a blend resin of these and a modified polyolefin is preferable.

Further, the adhesive layer 2 may be multilayered with different adhesive components. When the adhesive layer 2 is multilayered with different adhesive components, from the viewpoint of improving the lamination strength of the base layer 1 and the metal layer 3, the adhesive component disposed on the base layer 1 side is used as the base layer 1. It is preferable to select a resin having excellent adhesiveness to the metal layer 3 and an adhesive component having excellent adhesiveness to the metal layer 3 as the adhesive component disposed on the metal layer 3 side. When the adhesive layer 2 is multilayered with different adhesive components, specifically, the adhesive component disposed on the metal layer 3 side is preferably an acid-modified polyolefin, a metal-modified polyolefin, a polyester and an acid-modified polyolefin. Examples of the mixed resin, a resin containing a copolyester, and the like.

The thickness of the adhesive layer 2 is, for example, about 2 to 50 μm, preferably about 3 to 25 μm.

[Metal layer 3]
In the battery packaging material of the present invention, the metal layer 3 is a layer that not only improves the strength of the packaging material but also functions as a barrier layer for preventing water vapor, oxygen, light and the like from entering the inside of the battery. Specific examples of the metal that forms the metal layer 3 include metal foils such as aluminum, stainless steel, and titanium. Among these, aluminum is preferably used. In order to prevent wrinkles and pinholes during the production of the packaging material, soft aluminum, for example, annealed aluminum (JIS A8021P-O) or (JIS A8079P-O) is used as the metal layer 3 in the present invention. Is preferred.

The thickness of the metal layer 3 is, for example, about 10 to 200 μm, preferably about 20 to 100 μm.

Further, the metal layer 3 is preferably subjected to chemical conversion treatment on at least one surface, preferably at least the surface on the sealant layer 4 side, and more preferably both surfaces, for the purpose of stabilizing adhesion, preventing dissolution and corrosion. .. Here, the chemical conversion treatment is a treatment for forming an acid resistant film on the surface of the metal layer 3. The chemical conversion treatment is, for example, a chromate chromate treatment using a chromate compound such as chromium nitrate, chromium fluoride, chromium sulfate, chromium acetate, chromium oxalate, chromium biphosphate, acetyl acetate chromate, chromium chloride, and chromium chromium sulfate. A phosphoric acid chromate treatment using a phosphoric acid compound such as sodium phosphate, potassium phosphate, ammonium phosphate, and polyphosphoric acid; an aminated phenol polymer composed of repeating units represented by the following general formulas (1) to (4) Examples include chromate treatment using coalescence. In the aminated 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. Good.

In 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. R ¹ and R ² are the same or different and each represents a hydroxyl group, an alkyl group, or a hydroxyalkyl group. 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, an isobutyl group, Examples thereof include linear or branched alkyl groups having 1 to 4 carbon atoms such as tert-butyl group. Examples of the hydroxyalkyl group 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 a 3-hydroxypropyl group. Linear or branched chain having 1 to 4 carbon atoms in which one hydroxy group such as hydroxypropyl group, 1-hydroxybutyl group, 2-hydroxybutyl group, 3-hydroxybutyl group and 4-hydroxybutyl group is substituted. An alkyl group is mentioned. In the general formulas (1) to (4), X is preferably a hydrogen atom, a hydroxyl group, or a droxyalkyl group. The number average molecular weight of the aminated phenol polymer comprising the repeating units represented by the general formulas (1) to (4) is, for example, about 500 to about 1,000,000, preferably about 1000 to about 20,000.

As a chemical conversion treatment method for imparting corrosion resistance to the metal layer 3, phosphoric acid is coated with a dispersion of metal oxides such as aluminum oxide, titanium oxide, cerium oxide, and tin oxide and fine particles of barium sulfate, A method of forming a corrosion resistant treatment layer on the surface of the metal layer 3 by performing a baking treatment at 150° C. or higher can be mentioned. Further, a resin layer obtained by crosslinking a cationic polymer with a crosslinking agent may be formed on the anticorrosion treated layer. Here, as the cationic polymer, for example, polyethyleneimine, an ionic polymer complex composed of a polymer having polyethyleneimine and a carboxylic acid, a primary amine-grafted acrylic resin in which a primary amine is grafted to an acrylic main skeleton, polyallylamine or The derivative, aminophenol, etc. are mentioned. These cationic polymers may be used alone or in combination of two or more. 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. These cross-linking agents may be used alone or in combination of two or more.

For these chemical conversion treatments, one type of chemical conversion treatment may be performed alone, or two or more types of chemical conversion treatment may be performed in combination. Furthermore, these chemical conversion treatments may be performed using one type of compound alone, or may be performed using two or more types of compounds in combination. Among these, a chromate treatment is preferable, and a chromate treatment in which a chromate compound, a phosphoric acid compound, and an aminated phenol polymer are combined is more preferable.

The amount of the acid resistant film formed on the surface of the metal layer 3 in the chemical conversion treatment is not particularly limited, but for example, in the case of performing a chromate treatment by combining a chromic acid compound, a phosphoric acid compound, and an aminated phenol polymer. The chromic acid compound is about 0.5 to about 50 mg in terms of chromium, preferably about 1.0 to about 40 mg, and the phosphorus compound is about 0.5 to about 50 mg in terms of phosphorus per 1 m ² of the surface of the metal layer 3, preferably Of about 1.0 to about 40 mg, and the aminated phenolic polymer in an amount of about 1 to about 200 mg, preferably about 5.0 to 150 mg.

The chemical conversion treatment is performed by applying a solution containing a compound used for forming an acid resistant film to the surface of the metal layer 3 by a bar coating method, a roll coating method, a gravure coating method, a dipping method, or the like, and then applying the temperature of the metal layer 3. Is heated to about 70 to 200°C. Further, before subjecting the metal layer 3 to the chemical conversion treatment, the metal layer 3 may be previously 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. By performing the degreasing treatment in this way, the chemical conversion treatment of the surface of the metal layer 3 can be performed more efficiently.

[Sealant layer 4]
In the battery packaging material of the present invention, the sealant layer 4 corresponds to the innermost layer and is a layer that seals the battery element by heat-sealing the sealant layers during the assembly of the battery.

The resin component used in the sealant layer 4 is not particularly limited as long as it can be heat-welded, and examples thereof include polyolefin, cyclic polyolefin, carboxylic acid-modified polyolefin, and carboxylic acid-modified cyclic polyolefin.

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-ethylene block copolymer), polypropylene. Random copolymers (for example, random copolymers of propylene and ethylene); ethylene-butene-propylene terpolymers; and the like. 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, isoprene, and the like. Is mentioned. Examples of the cyclic monomer which is a constituent monomer of the cyclic polyolefin include cyclic alkenes such as norbornene; specifically, cyclic dienes such as cyclopentadiene, dicyclopentadiene, cyclohexadiene and norbornadiene. Among these polyolefins, cyclic alkenes are preferable, and norbornene is more preferable.

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

The carboxylic acid-modified cyclic polyolefin is obtained by copolymerizing a part of the monomers constituting the cyclic polyolefin by substituting α,β-unsaturated carboxylic acid or its anhydride, or by adding α,β to the cyclic polyolefin. -A polymer obtained by block-polymerizing or graft-polymerizing an unsaturated carboxylic acid or an anhydride thereof. The cyclic polyolefin modified with carboxylic acid is the same as described above. The carboxylic acid used for modification is the same as that used for modifying the acid-modified cycloolefin copolymer.

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

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

In the battery packaging material of the present invention, the sealant layer 4 may contain a lubricant. The type of lubricant is not particularly limited, and examples thereof include those exemplified in the item [Base material layer 1] above. When the sealant layer 4 contains a lubricant, the content thereof may be appropriately selected, but is preferably about 700 to 1200 ppm, more preferably about 800 to 1100 ppm. In the present invention, the content of the lubricant in the sealant layer 4 is the total amount of the lubricant present inside the sealant layer 4 and the lubricant present on the surface of the sealant layer 4.

The thickness of the sealant layer 4 can be appropriately selected, but it is about 10 to 100 μm, preferably about 15 to 50 μm.

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

The adhesive layer 5 is formed of an adhesive that can bond the metal layer 3 and the sealant layer 4 together. Regarding the adhesive used for forming the adhesive layer 5, the adhesive mechanism, the kind of the adhesive component, and the like are the same as in the case of the adhesive layer 2. The adhesive component used in the adhesive layer 5 is preferably a polyolefin resin, more preferably a carboxylic acid-modified polyolefin, and particularly preferably a carboxylic acid-modified polypropylene.

The thickness of the adhesive layer 5 is, for example, 2 to 50 μm, preferably 15 to 30 μm.

[Coating layer 6]
In the battery packaging material of the present invention, if necessary, on the base material layer 1 (metal layer of the base material layer 1) for the purpose of improving designability, electrolytic solution resistance, scratch resistance, moldability, and the like. A coating layer 6 may be provided on the side opposite to 3) as necessary. The coating layer 6 is the outermost layer when the battery is assembled.

The coating layer 6 can be formed of, for example, polyvinylidene chloride, polyester resin, urethane resin, acrylic resin, epoxy resin, or the like. Of these, the coating layer 6 is preferably formed of a two-component curable resin. Examples of the two-component curing type resin forming the coating layer 6 include a two-component curing type urethane resin, a two-component curing type polyester resin, and a two-component curing type epoxy resin. A matting agent may be added to the coating layer 6.

Examples of the matting agent include fine particles having a particle size of about 0.5 nm to 5 μm. The material of the matting agent is not particularly limited, and examples thereof include metals, metal oxides, inorganic substances, organic substances and the like. Also, the shape of the matting agent is not particularly limited, and examples thereof include a spherical shape, a fibrous shape, a plate shape, an amorphous shape, and a balloon shape. Specific examples of matting agents include talc, silica, graphite, kaolin, montmorillonite, montmorillonite, synthetic mica, hydrotalcite, silica gel, zeolite, aluminum hydroxide, magnesium hydroxide, zinc oxide, magnesium oxide, aluminum oxide. , Neodymium 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 matting agents may be used alone or in combination of two or more. Among these matting agents, preferred are silica silica, barium sulfate and titanium oxide from the viewpoint of dispersion stability and cost. Moreover, the surface of the matting agent may be subjected to various surface treatments such as insulation treatment and high dispersibility treatment.

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

The thickness of the coating layer 6 is not particularly limited as long as the above-mentioned function as the coating layer 6 is exerted, but is, for example, about 0.5 to 10 μm, preferably about 1 to 5 μm.

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 obtained by laminating each layer having a predetermined composition is obtained, but for example, the following method is exemplified. ..

First, a laminated body (hereinafter, also referred to as “laminated body A”) in which the base material layer 1, the adhesive layer 2, and the metal layer 3 are laminated in order is formed. To form the laminate A, specifically, the adhesive used for forming the adhesive layer 2 on the base material layer 1 or on the metal layer 3 whose surface has been subjected to chemical conversion treatment is applied by a gravure coating method or a roll method. It can be performed by a dry lamination method in which the metal layer 3 or the base material layer 1 is laminated and the adhesive layer 2 is cured after being applied and dried by a coating method such as a coating method.

Then, the sealant layer 4 is laminated on the metal layer 3 of the laminate A. When the sealant layer 4 is directly laminated on the metal layer 3, the resin component forming the sealant layer 4 may be applied on the metal layer 3 of the laminate A by a method such as a gravure coating method or a roll coating method. .. When the adhesive layer 5 is provided between the metal layer 3 and the sealant layer 4, for example, (1) the adhesive layer 5 and the sealant layer 4 are laminated on the metal layer 3 of the laminate A by coextrusion. Method (coextrusion lamination method), (2) separately forming a laminate in which the adhesive layer 5 and the sealant layer 4 are laminated, and laminating this on the metal layer 3 of the laminate A by the thermal lamination method, 3) The adhesive for forming the adhesive layer 5 is laminated on the metal layer 3 of the laminate A by an extrusion method, a solution coating method, a drying method at a high temperature, or a baking method, and the sheet shape is preliminarily formed on the adhesive layer 5. A method of laminating the sealant layer 4 formed into a film by the thermal lamination method, (4) a melted adhesive layer 5 between the metal layer 3 of the laminate A and the sealant layer 4 formed into a sheet in advance. A method (sand lamination method) of bonding the laminate A and the sealant layer 4 via the adhesive layer 5 while pouring them in may be mentioned. In addition, in order to strengthen the adhesiveness of the adhesive layer 2 and the adhesive layer 5 that is provided as necessary, you may provide to the heat processing of a hot-roll contact type, a hot air type, a near or far infrared type, etc. The conditions for such heat treatment include, for example, 150 to 250° C. and 1 to 5 minutes.

In the battery packaging material of the present invention, each layer constituting the laminate improves or stabilizes film-forming properties, lamination processing, final product secondary processing (pouching, embossing) suitability, etc., if necessary. Therefore, surface activation treatment such as corona treatment, blast treatment, oxidation treatment, and ozone treatment may be performed.

Further, in the method for producing a battery packaging material of the present invention, a corona treatment step is performed in which the surface of the base material layer 1 is subjected to corona treatment so that the contact angle of the surface on the base material layer 1 side is 80° or less. The corona treatment is as described above.

When printing the ink on the surface of the battery packaging material, the step of printing the ink on at least a part of the surface of the base material layer 1 is performed after the corona treatment step. The printing method is not particularly limited, but pad printing is preferable when printing is performed on the molded battery packaging material. In the battery packaging material obtained by the production method of the present invention, the contact angle of the surface of the base material layer 1 side is set to 80° or less, and therefore the ink is easily repelled in the base material layer having the lubricant on the surface. Ink printing can also be suitably performed by pad printing. Therefore, it is possible to preferably form, for example, a print such as a barcode, a pattern, or a character on at least a part of the surface of the base material layer 1. The ink used for printing is as described above.

4. Use of Battery Packaging Material The battery packaging material of the present invention is used as a packaging material for hermetically containing battery elements such as a positive electrode, a negative electrode and an electrolyte.

Specifically, a battery element having at least a positive electrode, a negative electrode, and an electrolyte, in the battery packaging material of the present invention, in a state where the metal terminals connected to each of the positive electrode and the negative electrode are projected outward, By covering the periphery of the element so that a flange portion (a region where the sealant layers contact each other) can be formed and sealing the sealant layers of the flange portion by heat sealing, a battery using a battery packaging material can be obtained. Provided. When a battery element is accommodated by using the battery packaging material of the present invention, the sealant portion of the battery packaging material of the present invention is used so that the sealant portion is on the inner side (the surface in contact with the battery element).

Since the battery packaging material of the present invention is used in the battery of the present invention, the ink is preferably printed on the surface of the battery after the battery packaging material is molded and the battery element is sealed. You can That is, since the contact angle of the surface of the battery of the present invention is set to 80° or less, the ink is preferably printed by the pad printing in which the ink is easily repelled in the base material layer on which the lubricant is present. Thus, it is possible to suitably form, for example, a barcode, a pattern, a character or the like on at least a part of the surface of the battery.

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

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

Examples 1-6 and Comparative Examples 1 and 2
<Manufacturing of packaging materials for batteries>
By laminating the adhesive layer 5 and the sealant layer 4 by a coextrusion method on a laminated body in which the base material layer 1/adhesive layer 2/metal layer 3 are laminated in order, the base material layer 1/adhesive layer 2/metal A packaging material for a battery was manufactured, which was composed of a laminate in which Layer 3/adhesive layer 5/sealant layer 4 were laminated in order. The specific manufacturing conditions of the battery packaging material are as follows.

In Examples 1-6 and Comparative Examples 1 and 2, the resin film (thickness 25 μm) and the metal layer 2 (40 μm) constituting the base material layer 1 were those shown in Table 1, respectively. Each of the resin films constituting the base material layer 1 contains 1200 ppm of erucic acid amide. In addition, the aluminum foil is a metal layer formed by a roll coating method so that the amount of chromium applied is 10 mg/m ² (dry weight) of the treatment liquid consisting of a phenol resin, a chromium fluoride compound (trivalent), and phosphoric acid. Was applied to both surfaces of the above and was baked for 20 seconds under the condition that the film temperature was 180° C. or higher to perform chemical conversion treatment.

First, a laminated body in which the base material layer 1/adhesive layer 2/metal layer 3 were laminated in order was produced. Specifically, on one surface (corona-treated surface) of the base material layer 1, an adhesive layer 2 composed of a two-component urethane adhesive composed of a polyester-based main agent and an isocyanate-based curing agent is formed to have a thickness of 3 μm. Was laminated with the metal layer 3 by a dry lamination method to prepare a laminate in which the base material layer 1/adhesive layer 2/metal layer 3 were laminated in this order.

Next, an acid-modified polypropylene resin constituting the adhesive layer 5 [an unsaturated carboxylic acid graft-modified random polypropylene graft-modified with an unsaturated carboxylic acid (acid-modified PP) and a polypropylene constituting the sealant layer 4 [random copolymer (PP) ] Was melted and co-extruded on the surface of the metal layer 3 of the laminate to laminate an adhesive layer 5 having a thickness of 23 μm and a sealant layer 4 having a thickness of 23 μm. As described above, a laminated body in which the base material layer 1/adhesive layer 2/metal layer 3/adhesive layer 5/sealant layer 4 were laminated in order was obtained. The obtained laminated body was once cooled, then heated to 180° C., and kept at that temperature for 1 minute to be heat-treated to obtain a battery packaging material.

In Examples 5 and 6, the coating layer 6 was provided on the surface of the base material layer 1 as follows.

(Matte coating)
In Example 5, an ink in which a resin (80% by mass) composed of polyester polyol and an isocyanate curing agent and silica particles (20% by mass) were mixed on the surface of the base material layer of the battery packaging material obtained above. Was printed by gravure coating to form a matte coating layer having a thickness of 3 μm.

(Black matte coating)
In Example 6, on the surface of the base material layer of the battery packaging material obtained above, a resin (70% by mass) consisting of polyester polyol and an isocyanate curing agent, carbon black (15% by mass), silica particles ( The ink mixed with 15% by mass) was printed by gravure coating to form a black matte coating layer having a thickness of 6 μm.

Further, the surface of the base material layer side of each of the obtained battery packaging materials was subjected to corona treatment under the following conditions to obtain each of the battery packaging materials of Example 1-6 and Comparative Examples 1 and 2. In Table 1, PET/nylon of the base material layer means that a PET layer (12 μm) and a nylon layer (15 μm) are laminated in order from the outermost surface side of the base material layer. Further, the matte coating/nylon means that the matte coating layer 6 is provided on the nylon constituting the base material layer 1, and the black matte coating is also the same.

[Corona treatment]
Using a corona surface treatment device (trade name CTW-0212) manufactured by Wedge Co., Ltd., at a set value of each output (Kw) shown in Table 1, at a constant speed of 10 MT/min, a base material layer of a battery packaging material. The surface on the 1st side was irradiated with corona discharge.

[Evaluation method of printing characteristics of ink]
Pad printing was performed on the surface of the packaging material for batteries of Examples 1-6 and Comparative Examples 1 and 2 on the side of the base material layer to evaluate the printing characteristics of the ink. As the pad printing machine, SPACE PAD 6GX manufactured by Mishima Co., Ltd. was used. As the ink, UV ink PJU-A black manufactured by Navitas Co., Ltd. was used. The ink printed on the surface of the base material layer side was cured by irradiation with UV for 30 seconds from a distance of 10 cm at an ultraviolet wavelength of 254 nm with a handy UV lamp SUV-4 manufactured by ASONE. The printed surface after curing was observed with an optical microscope, and the printing characteristics of the ink were evaluated according to the following criteria. The printing of the ink was performed in an environment of 24° C. and a relative humidity of 50%. The results are shown in Table 1.
○: Missing print is within 5% of the entire printed pattern ×: Missing print is more than 5% of the entire printed pattern

[Measurement of contact angle]
The contact angle of the surface of the base material layer side of each of the battery packaging materials of Examples 1-6 and Comparative Examples 1 and 2 was measured by using LSE-A210 manufactured by Nick Co., Ltd. and the base material after 5 seconds from the dropping of water. The contact angle of the water drop interface was measured. The results are shown in Table 1.

In Table 1, PET means polyethylene terephthalate and PBT means polybutylene terephthalate.

1 Base Material Layer 2 Adhesive Layer 3 Metal Layer 4 Sealant Layer 5 Adhesive Layer 6 Coating Layer

Claims (11)

At least a base material layer, a metal layer, and a sealant layer consisting of a laminated body sequentially laminated,
A packaging material for a battery, wherein the contact angle of the surface of the base material layer side 5 seconds after the dropping of water is 70° or more and 79° or less. The packaging material for batteries according to claim 1, which is used by printing ink on at least a part of the surface on the side of the base material layer. The battery packaging material according to claim 1 or 2, wherein ink is printed on at least a part of the surface of the base material layer side. The packaging material for a battery according to claim 1, wherein the surface of the base material layer side is corona-treated. The packaging material for batteries according to claim 1, wherein an adhesive layer is laminated between the base material layer and the metal layer. The packaging material for a battery according to claim 1, wherein an adhesive layer is laminated between the metal layer and the sealant layer. The packaging material for a battery according to claim 1, wherein the metal layer is formed of an aluminum foil. The packaging material for a battery according to claim 1, wherein a lubricant is present on the surface of the base material layer side. A battery, wherein a battery element including at least a positive electrode, a negative electrode, and an electrolyte is housed in the battery packaging material according to any one of claims 1 to 8. At least, a laminating step of laminating a base material layer, a metal layer, and a sealant layer to obtain a laminated body,
A corona treatment step of subjecting the surface of the base material layer side to corona treatment to make a contact angle of 70° or more and 79° or less 5 seconds after dropping water on the surface of the base material layer side;
A method of manufacturing a packaging material for a battery, comprising: The method for producing a battery packaging material according to claim 10, further comprising a step of printing ink on at least a part of the surface of the base material layer side after the corona treatment step.