WO2016125912A1

WO2016125912A1 - Packaging material for battery

Info

Publication number: WO2016125912A1
Application number: PCT/JP2016/053709
Authority: WO
Inventors: 篤史永井; 山下　力也; 天野　真; 堀　弥一郎
Original assignee: 大日本印刷株式会社
Priority date: 2015-02-06
Filing date: 2016-02-08
Publication date: 2016-08-11
Also published as: JP2016181503A; JP6750237B2

Abstract

　Provided is a packaging material for battery, made from a laminated film comprising at least a substrate layer, a metal layer and a thermofusible resin layer laminated in that order, wherein the glossiness on the surface on the substrate layer side of the laminated film is at least 150.

Description

Battery packaging materials

The present invention relates to a packaging material for a battery that can detect foreign substances existing inside with high accuracy.

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

For example, Patent Document 1 discloses a battery case including a biaxially stretched polyamide film layer as an outer layer, an unstretched thermoplastic resin film layer as an inner layer, and an aluminum foil layer disposed between the two film layers. A packaging material is disclosed.

JP 2008-287971 A

Battery packaging materials are generally manufactured as a strip-shaped laminated film in a production line, and are stored and transported as a wound body obtained by winding the film into a roll. And at the time of manufacture of a battery, the packaging material for batteries is unwound from a winding body, and it cuts and uses it so that it may become a predetermined shape according to the product specification of a battery.

The battery packaging material cut into a predetermined shape is generally shaped and used to enclose a battery element such as an electrolyte or an electrode. However, at the time of molding, pinholes may occur in the stretched portion of the battery packaging material, and the insulation of the battery packaging material may be reduced. When a battery is manufactured using such a battery packaging material that generates a pinhole, the pinhole is found only when the battery packaging material is formed in the battery manufacturing process. For this reason, when the packaging material for a battery is cut out from a wound body of the packaging material for a battery whose defects causing the pinhole are not managed and used for the production of the battery, the yield of the battery production may be reduced. is there.

The present invention has been made in view of such problems. That is, the main object of the present invention is to provide a battery packaging material that can detect foreign matter present inside with high accuracy.

The present inventor has intensively studied to solve the above problems. As a result, the following knowledge was obtained. That is, as described above, the battery packaging material is manufactured as a laminated film by laminating the layers constituting the battery packaging material. In such a manufacturing process, when laminating each layer of the laminated film, the foreign matter adhering to the device or the foreign matter scattered in the air falls on the layer in the laminating step, and the adjacent layer as it is. By being laminated, a foreign substance may be contained in the interface portion of the layer contained in the laminated film. In addition, foreign matters may adhere to the resin film, metal foil, and the like that are provided for lamination, which may be laminated as they are. Such foreign matter is, for example, dust or a metal piece. When a battery packaging material in which such foreign matter is present at the interface portion of the layer of the laminated film is molded, the portion where the foreign matter is present and other portions are formed. It has become clear that pinholes are likely to occur in areas where foreign matter exists due to differences in elongation.

And this inventor is the battery packaging material which consists of a laminated | multilayer film by which the base material layer, the metal layer, and the heat welding resin layer were laminated | stacked sequentially at least, The glossiness of the surface at the side of the base material layer of a laminated film By setting it to 150 or more, it is possible to detect the foreign matter existing in the inside (between the surface of the base material layer opposite to the metal layer (the outer surface of the base material layer) and the surface of the metal layer) with high accuracy. I found out that I can. The present invention has been completed by further studies based on these findings.

That is, this invention provides the invention of the aspect hung up below.
Item 1. At least a base film, a metal layer, and a heat-weldable resin layer are laminated films sequentially laminated,
A packaging material for a battery, wherein the glossiness of the surface of the laminated film on the substrate layer side is 150 or more.
Item 2. Item 2. The battery packaging material according to Item 1, wherein an adhesive layer is laminated between the base material layer and the metal layer.
Item 3. A decorative ink layer is laminated between the base material layer and the adhesive layer,
Item 3. The battery packaging material according to Item 2, wherein the decorative ink layer is formed of a resin composition including a metal thin film strip and a binder resin.
Item 4. Item 4. The battery packaging material according to

Item

2 or 3, wherein the adhesive layer comprises metal thin film strips.
Item 5. Item 5. The battery packaging material according to any one of Items 1 to 4, wherein the metal layer is formed of an aluminum foil or a stainless steel foil.
Item 6. Item 6. The battery packaging material according to any one of Items 1 to 5, wherein the base material layer has a thickness of 100 μm or less.
Item 7. Item 7. The battery packaging material according to any one of Items 2 to 6, wherein the adhesive layer has a thickness of 20 μm or less.
Item 8. Item 8. The battery packaging material according to any one of Items 1 to 7, wherein the glossiness of the surface of the laminated film on the substrate layer side is higher than the glossiness of the surface of the laminated film on the heat-weldable resin layer side. .
Item 9. The battery packaging material according to any one of claims 1 to 8, wherein a coating layer having a refractive index of 1.20 or more and 1.45 or less is laminated on the opposite side of the base material layer from the metal layer.
Item 10. The battery packaging material according to any one of claims 1 to 9, wherein a refractive index of the base material layer is 1.49 or more and 1.63 or less.
Item 11. The battery packaging material according to claim 2, wherein the adhesive layer has a refractive index of 1.60 or more and 1.72 or less.
Item 12. The battery packaging material according to any one of claims 1 to 11, wherein the laminate comprising all layers located outside the metal layer has a total light transmittance of 92% or more and a haze of 5.0% or less.
Item 13. Item 13. The battery packaging material according to any one of Items 1 to 12, wherein the battery packaging material is a wound body of the laminated film.
Item 14. Item 14. A battery in which a battery element including at least a positive electrode, a negative electrode, and an electrolyte is accommodated in the battery packaging material according to any one of Items 1 to 13.
Item 15. At least, a defect inspection method for battery packaging material comprising a laminated film in which a base material layer, a metal layer, and a heat-welding resin layer are laminated in this order,
The surface of the laminated film is imaged on the side opposite to the metal layer of the laminated film, with the laminated film having a glossiness of 150 or more on the surface of the laminated film as a defect inspection target. A step of recording position information of a foreign substance existing between the surface of the metal layer and the surface of the metal layer;
In accordance with the position information, a mark applying step for applying a mark to the laminated film so that the position of the foreign matter can be recognized;
A defect inspection method for battery packaging materials.

According to the present invention, in a battery packaging material comprising a laminated film in which at least a base material layer, a metal layer, and a heat-welding resin layer are sequentially laminated, the inside (surface on the opposite side of the base material layer from the metal layer) Thus, it is possible to provide a battery packaging material capable of detecting foreign matter existing between the metal layer and the surface of the metal layer with high accuracy.

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. 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 a laminated film in which at least a base material layer, a metal layer, and a heat-welding resin layer are sequentially laminated, and the glossiness of the surface of the laminated film on the base material layer side is 150 or more. It is characterized by being. Hereinafter, the battery packaging material of the present invention will be described in detail.

1. As shown in FIG. 1, the battery packaging material is composed of a laminated film in which at least a base material layer 1, a metal layer 3, and a heat-weldable resin layer 4 are sequentially laminated. In the battery packaging material of the present invention, the base material layer 1 is the outermost layer side, and the heat-welding resin layer 4 is the innermost layer. That is, when the battery is assembled, the heat-welding resin layers 4 located at the periphery of the battery element are thermally welded to seal the battery element, thereby sealing the battery element.

In addition, as shown in FIG. 1, the battery packaging material of the present invention is provided with an adhesive layer 2 between the base material layer 1 and the metal layer 3 as necessary for the purpose of enhancing the adhesion. It may be. In addition, as shown in FIG. 2, an adhesive layer 5 may be provided between the metal layer 3 and the heat-weldable resin layer 4 as necessary for the purpose of improving these adhesive properties. Moreover, as shown in FIG. 3 or FIG. 4, a decorative ink layer 6 may be further provided between the base material layer 1 and the metal layer 3 as necessary. By providing the decorative ink layer 6, the glossiness of the laminated film on the base material layer 1 side can be adjusted. When the adhesive layer 2 is further provided, the decorative ink layer 6 is preferably laminated between the base material layer 1 and the adhesive layer 2.

2. Glossiness of laminated film The present invention is characterized in that the glossiness of the surface of the laminated film constituting the battery packaging material on the substrate layer 1 side is 150 or more. Thus, in the battery packaging material of the present invention, since the glossiness on the base material layer side is higher than that of the conventional battery packaging material, for example, as described later, the laminated film is attached to the camera from the base material layer 1 side. It is possible to detect the foreign matter 7 existing between the base material layer 1 and the metal layer 3 with high accuracy by taking an image with the above. More specifically, in the battery packaging material of the present invention, since the glossiness of the surface of the base material layer 1 side is high, when the battery packaging material is observed from the base material layer 1 side, When the foreign matter 7 is present between the outer surface and the surface of the metal layer 3, the portion where the foreign matter 7 is present is observed darker than its surroundings. It becomes possible to detect with accuracy.

From the viewpoint of improving the detection accuracy of the foreign matter 7, the glossiness of the surface of the laminated film on the base material layer 1 side is preferably about 170 to 700, more preferably about 190 to 600. The measuring method of the glossiness of the surface of the laminated film on the base material layer 1 side is as follows.

(Measurement method of glossiness of laminated film)
According to JIS Z 8105, by using BYK-Gardner microtrigloss, the condition of an incident angle of light with respect to the surface of the laminated film on the base material layer 1 side is 60 °, and the observed Gu value is the glossiness.

The glossiness of the surface of the laminated film on the heat-weldable resin layer 4 side is not particularly limited, and examples thereof include about 80 to 120. The glossiness of the surface of the laminated film on the heat-welding resin layer 4 side can be measured in the same manner as the surface on the base material layer 1 side.

In the battery packaging material of the present invention, the glossiness of the surface of the laminated film on the base material layer 1 side is preferably higher than the glossiness of the surface of the laminated film on the heat-weldable resin layer 4 side. As will be described later, for example, when the metal foil for forming the metal layer 3 of the laminated film has a gloss with a high gloss on the surface on one side and a gloss with a low gloss on the surface on the other side, Is a method of laminating the metal layer 3 so that the surface with high glossiness faces the base material layer 1 side, whereby the glossiness of the surface on the base material layer 1 side of the laminated film is determined as the heat-welding resin layer of the laminated film. The glossiness of the surface on the 4 side can be made higher. Further, by laminating a decorative ink layer 6 described later and an adhesive layer 2 including a metal thin film strip between the base material layer 1 and the metal layer 3, the surface of the laminated film on the base material layer 1 side can also be obtained. The glossiness can be made higher than the glossiness of the surface of the laminated film on the heat-welding resin layer 4 side.

3. Composition of each layer forming base material for battery [base material layer 1]
In the battery packaging material, the base material layer 1 is a layer serving as a base material for the battery packaging material. About the raw material which forms the base material layer 1, it does not restrict | limit especially as long as it is provided with insulation. Examples of the material for forming the base material layer 1 include polyester, polyamide, epoxy, acrylic, fluororesin, polyurethane, silicon resin, phenol, polyetherimide, polyimide, and a mixture or copolymer thereof.

Specific examples of the polyester include polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polybutylene naphthalate, polyethylene isophthalate, polycarbonate, copolymerized polyester mainly composed of ethylene terephthalate, butylene terephthalate as a repeating unit. Examples thereof include a copolymer polyester mainly used. The copolymer polyester mainly composed of ethylene terephthalate is a copolymer polyester that polymerizes with ethylene isophthalate mainly composed of ethylene terephthalate (hereinafter, polyethylene (terephthalate / isophthalate)). Abbreviated), polyethylene (terephthalate / isophthalate), polyethylene (terephthalate / adipate), polyethylene (terephthalate / sodium sulfoisophthalate), polyethylene (terephthalate / sodium isophthalate), polyethylene (terephthalate / phenyl-dicarboxylate) And polyethylene (terephthalate / decanedicarboxylate). In addition, as a copolymer polyester mainly composed of butylene terephthalate as a repeating unit, specifically, a copolymer polyester that polymerizes with butylene isophthalate having butylene terephthalate as a repeating unit (hereinafter referred to as polybutylene (terephthalate / isophthalate)). For example), polybutylene (terephthalate / adipate), polybutylene (terephthalate / sebacate), polybutylene (terephthalate / decanedicarboxylate), polybutylene naphthalate and the like. These polyesters may be used individually by 1 type, and may be used in combination of 2 or more type. Polyester has the advantage of being excellent in electrolytic solution resistance and less likely to cause whitening due to the adhesion of the electrolytic solution, and is suitably used as a material for forming the base material layer 1.

Specific examples of polyamides include aliphatic polyamides such as nylon 6, nylon 66, nylon 610, nylon 12, nylon 46, and copolymers of nylon 6 and

nylon

6,6; terephthalic acid and / or Nylon 6I, Nylon 6T, Nylon 6IT, Nylon 6I6T (I represents isophthalic acid, T represents terephthalic acid) and the like containing a structural unit derived from isophthalic acid, polymethylene diamine-isophthalic acid-terephthalic acid copolymer polyamide Aromatic polyamides such as silylene adipamide (MXD6); alicyclic polyamides such as polyaminomethylcyclohexyl adipamide (PACM6); and lactam components and isocyanate components such as 4,4′-diphenylmethane diisocyanate. Polymerized polyamide, co Polyester amide copolymer and polyether ester amide copolymer is a copolymer of a focus polyamide and polyester and polyalkylene ether glycol; copolymers thereof, and the like. These polyamides may be used individually by 1 type, and may be used in combination of 2 or more type. The stretched polyamide film is excellent in 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 uniaxial or biaxially stretched resin film, or may be formed of an unstretched resin film. Among them, a uniaxially or biaxially stretched resin film, in particular, a biaxially stretched resin film has improved heat resistance by orientation crystallization, and thus is suitably used as the base material layer 1.

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

The base material layer 1 can be laminated with resin films of different materials in order to improve pinhole resistance and insulation when used as a battery package. Specific examples include a multilayer structure in which a polyester film and a nylon film are laminated, and a multilayer structure in which a biaxially stretched polyester and a biaxially stretched nylon are laminated. When making the base material layer 1 into a multilayer structure, each resin film may be adhere | attached through an adhesive agent, and may be laminated | stacked directly without an adhesive agent. In the case of bonding without using an adhesive, for example, a method of bonding in a hot melt state such as a co-extrusion method, a sand lamination method, or a thermal laminating method can be mentioned. Moreover, when making it adhere | attach through an adhesive agent, the adhesive agent to be used may be a two-component curable adhesive, or a one-component curable adhesive. Further, the bonding mechanism of the adhesive is not particularly limited, and may be any of a chemical reaction type, a solvent volatilization type, a heat melting type, a hot pressure type, an electron beam curing type such as UV and EB, and the like. As an adhesive component, polyester resin, polyether resin, polyurethane resin, epoxy resin, phenol resin resin, polyamide resin, polyolefin resin, polyvinyl acetate resin, cellulose resin, (meth) acrylic resin Resins, polyimide resins, amino resins, rubbers, and silicon resins can be used.

From the viewpoint of detecting foreign matter with higher accuracy, the refractive index of the base material layer is preferably 1.49 or more and 1.60 or less, more preferably 1.49 or more and 1.55 or less. The refractive index of the base material layer is a value measured for the resin constituting the base material layer using an Abbe refractometer, specifically, a value measured by the measurement method described in the examples. is there.

The thickness of the base material layer 1 is not particularly limited, but is preferably 100 μm or less, more preferably 70 μm or less, still more preferably about 2 μm to 50 μm, and particularly preferably 5 μm to 5 μm from the viewpoint of detecting foreign matter with higher accuracy. An example is about 30 μm.

[Coating layer]
If necessary, a coating layer (not shown) having a refractive index of 1.20 or more and 1.45 or less may be laminated on the side of the base material layer 1 opposite to the metal layer 3. The said coating layer is provided so that it may be located in the outermost surface of the packaging material for batteries. By providing the coating layer having such a refractive index on the outermost surface of the battery packaging material, the refractive index difference at the interface portion between the battery packaging material and air (interface between the coating layer and air) becomes small. In addition, the specular gloss of the surface of the battery packaging material can be increased. Due to these effects, it is possible to detect foreign matter with higher accuracy.

The refractive index of the coating layer is more preferably 1.20 or more and 1.38 or less. In addition, the refractive index of a coating layer is the value measured by the measuring method as described in an Example.

The resin for forming the coating layer is not particularly limited as long as the refractive index can be set to the above value, and examples thereof include porous films such as nanoporous silica and mesoporous silica, and amorphous fluororesins. The resin forming the coating layer may be used alone or in combination of two or more.

The thickness of the coating layer is determined by the wavelength and the refractive index because it is necessary to reverse the phases of the reflected light at the coating layer surface and the reflected light at the substrate interface. For example, in order to reduce the reflectance at a wavelength of 550 nm with high human visibility, it is desirable to control the thickness of the coating layer to a quarter wavelength, that is, around 100 nm.

[Decorative ink layer 6]
The decorative ink layer 6 is a layer provided as necessary for the purpose of adjusting the glossiness of the laminated film on the base material layer side. The decorative ink layer 6 preferably has a mirror-like metallic luster.

The decorative ink layer 6 is preferably laminated between the base material layer 1 and the metal layer 3 in that high glossiness can be imparted to the base material layer 1 side surface of the laminated film. In addition, when providing the contact bonding layer 2 mentioned later, it is preferable that the decoration ink layer 6 is laminated | stacked between the base material layer 1 and the contact bonding layer 2. FIG. When the decorative ink layer 6 is provided, the foreign matter 7 to be detected usually exists inside the decorative ink layer 6 and closer to the base material layer 1 than the decorative ink layer 6. The foreign matter 7 is also detected when the foreign matter 7 is present on the outermost surface of the battery packaging material.

The decorative ink layer 6 is not particularly limited as long as the decorative ink layer 6 includes a metal thin film strip and has a high luminance, but is preferably formed of a resin composition including the metal thin film strip and a binder resin. The decorative ink layer 6 is prepared by, for example, preparing a coating liquid in which metal thin film strips are dispersed in a binder resin, and printing or applying the coating liquid. On the other hand, a leafing effect oriented in a parallel direction occurs, and as a result, a layer having a high-brightness mirror-like metallic luster can be formed.

Examples of the metal material constituting the metal thin film strip include aluminum (Al), platinum (Pt), silver (Ag), tin (Sn), copper (Cu), iron (Fe), titanium (Ti), and chromium. Any of a group of metals made of (Cr), nickel (Ni), indium (In), molybdenum (Mo), tungsten (W), palladium (Pb), iridium (Ir), silicon (Si), and tantalum (Ta) Or an alloy using a group of these metals, or an oxide, nitride, sulfide, or carbide of these group of metals or an alloy thereof, preferably aluminum, silver , Tin, indium, and iridium, and more preferably aluminum.

As a method of making the metal material into a thin film, vapor deposition is given in the case of a metal material having a low melting point such as aluminum, and foil is given in the case of a malleable metal such as aluminum, gold, silver, copper, etc. In the case of a metal having high and poor malleability, sputtering and the like can be mentioned. Especially, the metal thin film strip obtained from the vapor deposition metal thin film is used preferably.

The thickness of the thin metal thin film is preferably an average thickness of 0.01 to 1 μm, more preferably an average thickness of 0.03 to 0.5 μm, from the viewpoint that a layer having a mirror-like metallic luster can be suitably formed. Is mentioned. The average thickness was an average value obtained as a result of measuring the thickness of 20 arbitrary thin metal thin strips from the cross-sectional SEM image of the coating film.

The size of the metal thin film strip in the plane direction is preferably an average major axis of 1 μm to 60 μm, more preferably an average major axis of 10 μm to 30 μm. If the size of the metal thin film strip in the surface direction is in the above range, the plate is not clogged when the ink for forming the decorative ink layer 6 is applied by the gravure printing method or the screen printing method. A high coating film can be formed. The average major axis was calculated by calculating the volume average from the particle size distribution measured by the laser diffraction method, and the 50% average particle diameter (median diameter) obtained as a result was used.

The ratio between the average major axis of the metal thin film strip and the average thickness, that is, the aspect ratio represented by the average major axis / average thickness is preferably 20 or more, and more preferably 50 or more.

The metal thin film strips are preferably surface-treated so as to increase dispersibility in the ink and prevent sedimentation. Examples of the surface treatment include a method in which a surface treatment agent is adsorbed on the surface of the metal thin film strip by a known method. Examples of the surface treatment agent include organic fatty acids such as stearic acid, oleic acid, and palmitic acid; isocyanates such as methylsilyl isocyanate; cellulose derivatives such as nitrocellulose, cellulose acetate propionate, cellulose acetate butyrate, and ethyl cellulose. Is mentioned.

Examples of the binder resin include resins usually used in conventional gravure ink, flexo ink, screen ink, paint, and the like. Specifically, examples of the binder resin include acrylic resin for paint, vinyl chloride resin, vinylidene chloride resin, vinyl chloride-vinyl acetate resin, ethylene-vinyl acetate resin, polyolefin resin, chlorinated olefin resin, ethylene- Polymeric resins such as acrylic resins; or polyurethane resins for paints, polyamide resins, urea resins, epoxy resins, polyester resins, petroleum resins, cellulose derivative resins and the like are preferably used. These resins may be used or used in combination with those obtained by chemically bonding polar groups such as carboxylic acid group, phosphoric acid group, sulfonic acid group, amino group and quaternary ammonium base.

The decorative ink layer 6 is formed by applying a coating liquid in which the above-described metal thin film strip and binder resin are dispersed in a solvent to one surface of the base material layer 1 and drying and curing as necessary. Is done. What is necessary is just to select a solvent suitably according to the kind etc. of binder resin to apply. Preparation, drying, and curing of the coating liquid may be performed by a known method.

The content of the metal thin film strip is preferably 5 to 60% by mass, more preferably 20 to 50%, based on the total solid content in the coating liquid, in that a layer having a mirror-like metallic luster can be formed. % By weight.

The thickness of the decorative ink layer 6 is not particularly limited, but is preferably 0.1 to 5 μm, more preferably 0.5 to 3 μm for the purpose of increasing the luminance on the base layer 1 side of the laminated film. It is done.

[Adhesive layer 2]
In the battery packaging material, the adhesive layer 2 is a layer provided as necessary for the purpose of increasing the adhesive strength between the base material layer 1 and the metal layer 3. In addition, as above-mentioned, when the packaging material for batteries is provided with the decoration ink layer 6, it is preferable to laminate | stack in order of the base material layer 1, the decoration ink layer 6, the contact bonding layer 2, and the metal layer 3. FIG.

The adhesive layer 2 is formed of an adhesive capable of adhering the base material layer 1 and the metal layer 3. The adhesive used for forming the adhesive layer 2 may be a two-component curable adhesive or a one-component curable adhesive. Furthermore, the adhesive 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 pressure type, and the like.

Specific examples of the resin component of the adhesive that can be used to form the adhesive layer 2 include polyesters such as polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polybutylene naphthalate, polyethylene isophthalate, polycarbonate, and copolyester. Resin; Polyether adhesive; Polyurethane adhesive; Epoxy resin; Phenol resin resin; Polyamide resin such as nylon 6, nylon 66, nylon 12, copolymer polyamide; polyolefin, acid-modified polyolefin, metal-modified polyolefin, etc. Polyolefin resin; polyvinyl acetate resin; cellulose adhesive; (meth) acrylic resin; polyimide resin; amino resin such as urea resin and melamine resin; chloroprene rubber, nitrile rubber, steel Silicone resin; - down rubber such as butadiene rubber fluorinated ethylene propylene copolymer, and the like. These adhesive components may be used individually by 1 type, and may be used in combination of 2 or more type. The combination mode of two or more kinds of adhesive components is not particularly limited. 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 thereof include a mixed resin of polyester and acid-modified polyolefin, and a mixed resin of polyester and metal-modified polyolefin. Among these, extensibility, durability under high-humidity conditions, anti-hypertensive action, thermal deterioration-preventing action during heat sealing, etc. 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 two-component curable adhesive; polyamide, polyester, or a blended resin of these with a modified polyolefin is preferable.

Also, 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 between the base material layer 1 and the metal layer 3, the adhesive component disposed on the base material layer 1 side is used as the base material layer 1. It is preferable to select a resin having excellent adhesion to the metal layer 3 and to select an adhesive component having excellent adhesion 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. And a resin containing a copolyester.

From the viewpoint of detecting foreign matter with higher accuracy, the refractive index of the adhesive layer is preferably 1.60 or more and 1.72 or less, more preferably 1.65 or more and 1.72 or less. In addition, the refractive index of an adhesive layer is the value measured by the measuring method as described in an Example.

The thickness of the adhesive layer 2 is not particularly limited, but is preferably 1 to 10 μm, more preferably 2 to 5 μm from the viewpoint of detecting foreign matter with higher accuracy.

Also, the adhesive layer 2 may include metal thin film strips. When the adhesive layer 2 includes the metal thin film strip, the glossiness of the substrate-side surface of the laminated film can be adjusted without providing a decorative ink layer.

The metal thin film strip included in the adhesive layer 2 is preferably the same material and shape as the metal thin film strip described in the section of the decorative ink layer 6.

When the adhesive layer 2 includes metal thin film strips, the content of the metal thin film strips is preferably 10 to 60% by mass, more preferably 20 to 50% by mass in the adhesive layer. When the adhesive layer 2 includes metal thin film strips, the thickness of the adhesive layer 2 is preferably 0.5 to 5 μm, more preferably 1 to 3 μm.

[Metal layer 3]
In the battery packaging material, the metal layer 3 is a layer that functions as a barrier layer for preventing water vapor, oxygen, light, and the like from entering the battery, in addition to improving the strength of the battery packaging material. Specific examples of the metal constituting the metal layer 3 include aluminum, stainless steel, and titanium, and preferably aluminum and stainless steel. The metal layer 3 can be formed by metal foil or metal vapor deposition, preferably by metal foil, and more preferably by aluminum foil or stainless steel foil. From the viewpoint of preventing the generation of wrinkles and pinholes in the metal layer 3 during the production of the battery packaging material, for example, a soft aluminum foil such as annealed aluminum (JIS A8021P-O, JIS A8079P-O) is used. More preferably, it is formed.

From the viewpoint of improving the detection accuracy of the foreign matter 7, the glossiness of the surface of the metal layer 3 on the base material layer 1 side is preferably 100 or more, preferably about 170 to 800, more preferably about 200 to 650. . As described above, when the decorative ink layer 6 is provided, the glossiness of the laminated film can be suitably increased even when the glossiness of the surface of the metal layer 3 on the base material layer 1 side is low. When the decorative ink layer 6 is not provided, the glossiness is preferably 150 or more. The glossiness of the surface of the metal layer 3 on the substrate layer 1 side can be measured in the same manner by applying the above-described method for measuring the glossiness of the laminated film to the surface of the metal layer 3.

The glossiness of the surface of the metal layer 3 on the heat-welding resin layer 4 side is not particularly limited, and may be about 10 to 300, for example. The glossiness of the surface of the laminated film on the heat-welding resin layer 4 side can be measured in the same manner as the surface on the base material layer 1 side.

In the battery packaging material of the present invention, the glossiness of the surface of the metal layer 3 on the base material layer 1 side is preferably higher than the glossiness of the surface of the metal layer 3 on the heat-weldable resin layer 4 side. For example, as the metal foil forming the metal layer 3 of the laminated film, the glossiness is high when the glossiness of the surface on one side is high and the glossiness of the surface on the other side is low. What is necessary is just to laminate | stack the metal layer 3 so that a high surface may face the base material layer 1 side.

The thickness of the metal layer 3 is not particularly limited, but can be, for example, about 10 μm to 200 μm, preferably about 20 μm to 100 μm.

The metal layer 3 is preferably subjected to chemical conversion treatment on at least one side, 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 metal layer. As the chemical conversion treatment, for example, chromate chromate using chromic acid compounds such as chromium nitrate, chromium fluoride, chromium sulfate, chromium acetate, chromium oxalate, chromium biphosphate, chromic acetyl acetate, chromium chloride, potassium sulfate chromium, etc. Treatment: Phosphoric acid chromate treatment using a phosphoric acid compound such as sodium phosphate, potassium phosphate, ammonium phosphate, polyphosphoric acid; aminated phenol having a repeating unit represented by the following general formulas (1) to (4) Examples include chromate treatment using a polymer. In the aminated phenol polymer, the repeating units represented by the following general formulas (1) to (4) may be contained singly or in any combination of two or more. Also 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. 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 a linear or branched alkyl group having 1 to 4 carbon atoms such as a 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, 3- C1-C4 straight or branched chain in which one hydroxy group such as hydroxypropyl group, 1-hydroxybutyl group, 2-hydroxybutyl group, 3-hydroxybutyl group, 4-hydroxybutyl group is substituted An alkyl group is mentioned. In the general formulas (1) to (4), the alkyl group and hydroxyalkyl group represented by X, R ¹ and R ² may be the same or different. 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 aminated phenol polymer having a repeating unit represented by the general formulas (1) to (4) is preferably, for example, 500 to 1,000,000, more preferably about 1,000 to 20,000. preferable.

In addition, as a chemical conversion treatment method for imparting corrosion resistance to the metal layer 3, a metal oxide such as aluminum oxide, titanium oxide, cerium oxide, tin oxide, or barium sulfate fine particles dispersed in phosphoric acid is coated. 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 further formed on the corrosion-resistant treatment layer. Here, examples of the cationic polymer include polyethyleneimine, an ionic polymer complex composed of a polymer having polyethyleneimine and a carboxylic acid, a primary amine graft acrylic resin obtained by graft polymerization of a primary amine on an acrylic main skeleton, and polyallylamine. Or the derivative, aminophenol, etc. are mentioned. As these cationic polymers, only one type may be used, or two or more types may be used in combination. Examples of the crosslinking 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, and a silane coupling agent. As these crosslinking agents, only one type may be used, or two or more types may be used in combination.

As the chemical conversion treatment, only one type of chemical conversion treatment may be performed, or two or more types of chemical conversion processing may be performed in combination. Furthermore, these chemical conversion treatments may be carried out using one kind of compound alone, or may be carried out using a combination of two or more kinds of compounds. Among the chemical conversion treatments, chromic acid chromate treatment, chromate treatment combining a chromic acid compound, a phosphoric acid compound, and an aminated phenol polymer are 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. For example, if the above chromate treatment is performed, a chromic acid compound is present per 1 m ² of the surface of the metal layer 3. About 0.5 mg to about 50 mg in terms of chromium, preferably about 1.0 mg to about 40 mg, phosphorus compound is about 0.5 mg to about 50 mg in terms of phosphorus, preferably about 1.0 mg to about 40 mg, and aminated phenol weight It is desirable that the combination is contained in a proportion of about 1 mg to about 200 mg, preferably about 5.0 mg to 150 mg.

In the chemical conversion treatment, a solution containing a compound used for forming an acid-resistant film is applied to the surface of the metal layer by a bar coating method, a roll coating method, a gravure coating method, an immersion method, or the like, and then the temperature of the metal layer is 70. It is carried out by heating so as to reach about 200 ° C to 200 ° C. Further, before the chemical conversion treatment is performed on the metal layer, the metal layer 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, it becomes possible to more efficiently perform the chemical conversion treatment on the surface of the metal layer.

In addition, when the surface of the base layer 1 side of the metal layer 3 is subjected to chemical conversion treatment, the glossiness of the surface subjected to the chemical conversion treatment is equal to the glossiness value of the surface of the base layer 1 side of the metal layer 3 described above. Become. The same applies to the heat-welding resin layer 4 side.

[Adhesive layer 5]
In the battery packaging material, an adhesive layer 5 is provided between the metal layer 3 and the heat-weldable resin layer 4 as necessary for the purpose of firmly bonding the metal layer 3 and the heat-weldable resin layer 4 or the like. May be further provided.

The adhesive layer 5 is formed of an adhesive component capable of bonding the metal layer 3 and a heat-welding resin layer 4 described later. The adhesive used for forming the adhesive layer 5 may be a two-component curable adhesive or a one-component curable adhesive. Moreover, it does not specifically limit about the adhesion | attachment mechanism of the adhesive agent component used for formation of the contact bonding layer 5, For example, a chemical reaction type | mold, a solvent volatilization type | mold, a hot-melt type, a hot-pressure type etc. are mentioned.

Specific examples of the adhesive component that can be used to form the adhesive layer 5 include polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polybutylene naphthalate, polyethylene isophthalate, polycarbonate, copolymer polyester, and other polyester resins; polyethers Polyurethane adhesives; epoxy resins; phenol resin resins; polyamide resins such as nylon 6, nylon 66, nylon 12, copolymer polyamides; polyolefins such as polyolefins, carboxylic acid modified polyolefins, metal modified polyolefins Resin, polyvinyl acetate resin; cellulose adhesive; (meth) acrylic resin; polyimide resin; urea resin, melamine resin and other amino resins; chloroprene rubber, nitrile rubber - styrene rubbers such as butadiene rubber; and silicone resins. These adhesive components may be used alone or in combination of two or more.

The thickness of the adhesive layer 5 is not particularly limited, but is preferably about 1 μm to 40 μm, for example, and more preferably about 2 μm to 30 μm.

[Heat welding resin layer 4]
In the battery packaging material, the heat-welding resin layer 4 is a layer constituting the innermost layer of the battery packaging material when the battery is assembled. When assembling the battery, the surfaces of the heat-welding resin layer 4 can be brought into contact with each other, and the contacted portion can be heat-welded to seal the battery element.

The heat-weldable resin layer 4 is preferably formed of a thermoplastic resin. Examples of the thermoplastic resin include polyolefin, cyclic polyolefin, carboxylic acid-modified polyolefin, carboxylic acid-modified cyclic polyolefin, and the like.

Specific examples of polyolefins include polyethylene such as low density polyethylene, medium density polyethylene, high density polyethylene, and linear low density polyethylene; homopolypropylene, polypropylene block copolymers (for example, block copolymers of propylene and ethylene), polypropylene Crystalline or amorphous polypropylene such as 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.

Cyclic polyolefin is a copolymer of olefin and cyclic monomer. Examples of the olefin include ethylene, propylene, 4-methyl-1-pentene, styrene, butadiene, and isoprene. Examples of the cyclic monomer include cyclic alkenes such as norbornene; cyclic dienes such as cyclopentadiene, dicyclopentadiene, cyclohexadiene, norbornadiene, and the like. Among these polyolefins, a cyclic alkene is preferable, and norbornene is more preferable.

Carboxylic acid-modified polyolefin is a polymer obtained by modifying polyolefin with 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 is a copolymer obtained by copolymerizing a part of the monomer constituting the cyclic polyolefin in place of the α, β-unsaturated carboxylic acid or its acid anhydride, or α, β with respect to the cyclic polyolefin. -A polymer obtained by block polymerization or graft polymerization of an unsaturated carboxylic acid or its acid anhydride. The cyclic polyolefin to be modified with carboxylic acid can be the same as the above cyclic polyolefin. The carboxylic acid used for modification can be the same as that used for modification of the acid-modified cycloolefin copolymer.

Among these thermoplastic resins, preferably crystalline or amorphous polyolefins, cyclic polyolefins, and blended polymers thereof; more preferably polyethylene, polypropylene, copolymers of ethylene and norbornene, and two of them The above blend polymer is mentioned.

The heat-weldable resin layer 4 may be formed from only one type of resin component, or may be formed from a blend polymer in which two or more types of resin components are combined. Furthermore, the heat-welding resin layer 4 may be formed of only one layer, or may be formed of a plurality of layers of two or more layers by the same or different resin components. When the heat-welding resin layer 4 is formed of a plurality of layers, the heat-welding resin layer 4 is preferably formed of polypropylene and a layer formed of carboxylic acid-modified polypropylene in order from the metal layer 3 side. One in which two layers are laminated is mentioned.

The thickness of the heat-welding resin layer 4 is not particularly limited, but may be, for example, about 2 μm to 200 μm, preferably about 5 μm to 150 μm, and more preferably 10 μm to 100 μm.

In the battery packaging material of the present invention, the total light transmittance of the laminate composed of all layers located outside the metal layer 3 (that is, the base material layer 1 side) is 92% or more, and the haze is 5.0% or less. It is preferable that Thereby, the detection precision of a foreign material can be improved further. The total light transmittance is preferably 93% or more and 95% or less. The haze is preferably 2.0% or more and 4.0% or less. The said total light transmittance and haze are the values measured by the method as described in an Example, respectively.

[Foreign matter 7]
In the battery packaging material of the present invention, even when the foreign matter 7 exists between the outer surface of the base material layer 1 and the surface of the metal layer 3, the foreign matter 7 can be detected with high accuracy. As described above, the battery packaging material is generally manufactured as a strip-shaped laminated film in a production line, and stored, transported, and the like as a wound body obtained by winding the film. In the manufacturing process of battery packaging materials, when laminating each layer of the laminated film, the foreign matter adhering to the device and the foreign matter scattered in the air fall on the layer in the laminating step and are directly adjacent to each other By laminating with a layer, a foreign substance may be contained in the interface part of the layer contained in a lamination film. Moreover, the foreign material may adhere also to the resin film, metal foil, etc. which comprise each layer of a laminated | multilayer film. When a battery packaging material in which such foreign matter is present at the interface portion of the laminated film layer is molded, there are pinholes in the foreign matter part due to differences in elongation between the foreign matter part and other parts. It tends to occur.

In particular, when the battery packaging material is a laminated film winding body, since the size of the laminated film is large, there is a high possibility that foreign matter 7 is present in the winding body.

The size of the foreign material 7 is not particularly limited, but the foreign material 7 having an area of 0.4 mm ² or more when viewed from the lamination direction of the laminated film is particularly likely to cause pinholes during molding. If foreign matter 7 of a large size is included, it is desirable to remove it as a defective product from the product. For example, the number of foreign substances 7 having an area of 0.4 mm ² or more is generally about 0 to 10 per 100 m of a laminated film having a width of 80 to 600 mm.

In the present invention, the foreign matter 7 can be present inside or at the interface portion of at least two layers included in the laminated film. Specifically, the foreign material 7 can be present at least in the base material layer 1 and at the interface portion between the base material layer 1 and the metal layer 3. It may also exist in the inside of the layer 2, the interface portion between the base material layer 1 and the adhesive layer 2, and the interface portion between the adhesive layer 2 and the metal layer 3. Moreover, when a laminated film has the decoration ink layer 6, the inside of the decoration ink layer 6, the interface part of the base material layer 1 and the decoration ink layer 6, the interface part of the decoration ink layer 6 and the adhesive layer 2, etc. Can also exist.

Among these, the foreign matter 7 may be included. In particular, when the foreign matter 7 exists in the interface portion between the base material layer 1 and the metal layer 3, the interface portion between the adhesive layer 2 and the metal layer 3, or the adhesive layer 2, the pin Holes are likely to occur. This is considered to be caused by a large difference in tensile strength between the base material layer 1 and the metal layer 3. Specifically, since the tensile strength of the base material layer 1 is usually larger than the tensile strength of the metal layer 3, the base material layer 1 and the metal layer 3 are laminated rather than the case where the metal layer 3 is formed alone. The tensile strength when molding the battery packaging material is increased. Therefore, in the interface portion between the base material layer 1 and the metal layer 3, the interface portion between the adhesive layer 2 and the metal layer 3, or the portion where the foreign material 7 exists due to the presence of the foreign material 7 in the adhesive layer 2. If the base material layer 1 and the metal layer 3 are not properly bonded, the foreign material 7 of the metal layer 3 is caused by a large force applied to the metal layer 3 when the battery packaging material is stretched by molding. It is considered that pinholes are likely to occur in existing portions.

In addition, if foreign matter 7 is present at the interface portion between the base material layer 1 and the metal layer 3 or the interface portion between the adhesive layer 2 and the metal layer 3, the metal layer 3 is damaged by the foreign matter 7 during the molding of the battery packaging material. Is likely to cause pinholes.

Although it does not specifically limit as the foreign material 7, Generally, they are dust, a metal piece, the oligomer of the resin which forms the base material layer 1, a carbide | carbonized_material, etc. For example, the thickness of the foreign material 7 having an area of 0.4 mm ² or more is usually 2 μm or more and 50 μm or less. In addition, the thickness of the foreign material 7 means the thickness of the foreign material 7 in the lamination direction of the laminated film.

The battery packaging material of the present invention may be a laminated film roll. When the battery packaging material is a wound body, the wound body is configured by winding the laminated film in a roll shape. The wound body may be wound so that the heat-welding resin layer 4 of the battery packaging material is inside, or wound so that the base material layer 1 is inside. There may be.

In the wound body, the length of the laminated film constituting the battery packaging material is not particularly limited, but is, for example, 200 m or more, preferably about 200 to 600 m. The width of the laminated film is, for example, about 0.01 to 1 m, preferably about 0.1 to 1 m. The thickness of the laminated film is, for example, 200 μm or less, preferably about 50 to 200 μm, more preferably about 65 to 130 μm. In the roll-shaped winding body, the diameter of the circular cross section in the direction perpendicular to the width direction of the laminated film is preferably 150 mm or more, more preferably 220 mm or more. In addition, the upper limit of the diameter of the circular section is usually about 350 mm.

4). 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 layers having a predetermined composition are laminated is obtained. For example, the following method is exemplified. .

First, a laminated body in which the base material layer 1, the adhesive layer 2, and the metal layer 3 are laminated in this order (hereinafter also referred to as “laminated body A”) is formed. Specifically, the laminate A is formed by extruding an adhesive used for forming the adhesive layer 2 on the base layer 1 or the metal layer 3 whose surface is subjected to chemical conversion treatment, if necessary. 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 method or a roll coating method.

Next, the heat-welding resin layer 4 is laminated on the metal layer 3 of the laminate A. When directly laminating the heat-weldable resin layer 4 on the metal layer 3, the resin component constituting the heat-weldable resin layer 4 is formed on the metal layer 3 of the laminate A by a gravure coating method, a roll coating method or the like. What is necessary is just to apply | coat by the method. When the adhesive layer 5 is provided between the metal layer 3 and the heat-weldable resin layer 4, for example, (1) the adhesive layer 5 and the heat-weldable resin layer 4 are formed on the metal layer 3 of the laminate A. A method of laminating by coextrusion (coextrusion lamination method), (2) Separately, a laminate in which the adhesive layer 5 and the heat-welding resin layer 4 are laminated is formed on the metal layer 3 of the laminate A. Laminating by thermal lamination method, (3) Laminating the adhesive for forming the adhesive layer 5 on the metal layer 3 of the laminate A by an extrusion method or a solution-coated high temperature drying or baking method, A method of laminating the heat-weldable resin layer 4 previously formed into a sheet on the adhesive layer 5 by a thermal lamination method; (4) the metal layer 3 of the laminate A and the heat-weldability formed into a sheet in advance. Bonded with the resin layer 4 While pouring 5, a method of bonding a laminate A and the heat-fusible resin layer 4 through the adhesive layer 5 (sand lamination method) and the like.

As described above, base material layer 1 / adhesive layer 2 provided as necessary / metal layer 3 whose surface is subjected to chemical conversion treatment as needed / adhesive layer 5 provided as needed / heat-weldable resin layer In order to strengthen the adhesiveness of the adhesive layer 2 provided as necessary and the adhesive layer 5 provided as necessary, a hot roll contact type and a hot air type are further formed. You may use for near- or far-infrared type heat processing. An example of such heat treatment conditions is 150 to 250 ° C. for 1 to 5 minutes.

Moreover, when manufacturing the packaging material for batteries which consists of a laminated | multilayer film with which the decorative ink layer 6 was laminated | stacked, the laminated body by which the base material layer 1, the decorative ink layer 6, the contact bonding layer 2, and the metal layer 3 were laminated | stacked in order first. (Hereinafter also referred to as “laminate B”). Specifically, the layered product B is formed by first coating and drying a coating liquid containing a metal thin film strip and a binder resin on the base material layer 1 to form the decorative ink layer 6. After the adhesive used for forming the adhesive layer 2 on the metal layer 3 is applied and dried by an application method such as an extrusion method, a gravure coating method, or a roll coating method, the decorative ink layer 6 on the base material layer 1 is applied. Then, the adhesive layer 2 on the metal layer 3 may be laminated and the adhesive layer 2 may be cured by a dry lamination method. Next, the heat-weldable resin layer 4 is preferably laminated on the metal layer 3 of the laminate B by the same method as the laminate A described above.

When providing a coating layer, a coating layer is laminated | stacked on the surface on the opposite side to the metal layer 3 of the base material layer 1. FIG. The coating layer can be formed, for example, by applying the above-described resin for forming the coating layer to the surface of the base material layer 1. The order of the step of laminating the metal layer 3 on the surface of the base material layer 1 and the step of laminating the coating layer on the surface of the base material layer 1 are not particularly limited. For example, after forming a coating layer on the surface of the base material layer 1, the metal layer 3 may be formed on the surface of the base material layer 1 opposite to the coating layer.

As described above, coating layer / base material layer 1 provided as necessary / decorative ink layer 6 provided as needed / adhesive layer 2 provided as needed / surface is subjected to chemical conversion treatment as necessary. A laminated film composed of metal layer 3 / adhesive layer 5 provided as necessary / heat-weldable resin layer 4 is formed. Adhesive layer 2 provided as needed and adhesive layer 5 provided as needed In order to strengthen the adhesiveness, heat treatment similar to that described above may be provided.

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

5). Defect inspection method for battery packaging material The defect inspection method for battery packaging material of the present invention (hereinafter sometimes simply referred to as “defect inspection method”) includes at least a base material layer 1, a metal layer 3, and thermal welding. A method for inspecting defects in a battery packaging material comprising a laminated film in which the conductive resin layer 4 is laminated in this order, wherein the laminated film having a glossiness of 150 or more on the substrate layer 1 side of the laminated film is inspected for defects. As an object, the surface of the laminated film (the surface on the base material layer 1 side) is imaged, and the surface of the laminated film on the base material layer 1 side of the surface of the metal layer 3 from the surface opposite to the metal layer 3 is measured It is characterized by comprising a step of recording the position information of the foreign matter 7 existing in between, and a mark applying step of applying a mark to the laminated film so that the position of the foreign matter 7 can be recognized according to the position information.

In the defect inspection method of the present invention, a laminated film having a glossiness of 150 or more on the surface of the laminated film on the substrate layer 1 side is used as a defect inspection target. For details of the laminated film used in the defect inspection apparatus, refer to “1. Laminated structure of battery packaging material”, “2. Glossiness of laminated film” and “3. Composition of each layer forming battery packaging material”. This is as described in the column. As described above, when the battery packaging material is cut out from the wound body of the battery packaging material for which the defect causing the pinhole is not managed and used for manufacturing the battery, the battery manufacturing yield decreases. There is. For this reason, it is preferable that the battery packaging material provided for the defect inspection method of the present invention is a wound body before cutting.

In the defect inspection method of the present invention, first, a recording process is performed in which the surface on the base material layer 1 side of the laminated film of battery packaging material is imaged using a camera or the like, and the position information of the foreign matter 7 is recorded. At this time, it is preferable to record information such as the size and height of the foreign matter 7. The recording process for recording the position information of the foreign matter 7 can be performed by using a known defect inspection apparatus used for defect inspection such as fish eye in the film. A commercial item can be used as such a defect inspection apparatus.

Next, in accordance with the position information obtained in the recording process, a mark applying process for applying a mark to the laminated film is performed so that the position of the foreign material 7 can be recognized. The position of the mark is not particularly limited as long as it is provided so that the position of the foreign object 7 can be recognized. For example, the mark may be provided on the foreign object 7 or may be provided in the vicinity of the foreign object 7. May be. Such a mark application process can also be performed by using a known defect inspection apparatus as described above. The type of the mark is not particularly limited as long as the position can be recognized. For example, an ink or the like used for a general film defect inspection apparatus can be used in the present invention.

As described above, the defect inspection method of the present invention makes it possible to manage the position, size, number, and the like of the foreign matter 7 of the laminated film having defects that cause pinholes. That is, for example, by applying the defect inspection method of the present invention to a battery packaging material, it becomes possible to manage so that the position of such foreign matter 7 in the laminated film can be recognized. It is possible to easily recognize the position of the generated defect. Therefore, for example, when the battery packaging material unwound from the winding body is cut out and used for sealing the battery element, the battery can be manufactured by avoiding a defective part that causes pinholes. The yield of battery manufacturing can be improved.

Further, by applying the defect inspection method of the present invention, the foreign matter 7 that can be recognized by the mark can be removed. Therefore, by cutting out the battery packaging material unwound from the winder and sealing the battery element, it is possible to suitably suppress the production of a battery having a defect that causes pinholes. In addition, the yield of battery manufacturing can be improved.

6). Application of Battery Packaging Material The battery packaging material of the present invention is used as a packaging material for sealing and housing battery elements such as a positive electrode, a negative electrode, and an electrolyte.

Specifically, a battery element including at least a positive electrode, a negative electrode, and an electrolyte is used in the battery packaging material of the present invention, with the metal terminal connected to each of the positive electrode and the negative electrode protruding outward. Covering the periphery of the element so that a flange portion (region where the heat-welding resin layers contact each other) can be formed, and heat-sealing and sealing the heat-welding resin layers of the flange portion, thereby packaging the battery. A battery using the material is provided. In addition, when accommodating a battery element using the battery packaging material of the present invention, the battery packaging material of the present invention is used such that the sealant portion is on the inner side (surface in contact with the battery element).

The battery packaging material 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 battery packaging material of the present invention is applied is not particularly limited. For example, a lithium ion battery, a lithium ion polymer battery, a lead battery, a nickel / hydrogen battery, a nickel / cadmium battery , Nickel / iron livestock batteries, nickel / zinc livestock batteries, silver oxide / zinc livestock batteries, metal-air batteries, polyvalent cation batteries, capacitors, capacitors and the like. Among these secondary batteries, lithium ion batteries and lithium ion polymer batteries are suitable applications for 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.
In addition, the measuring method of the refractive index of each layer and the measuring method of the total light transmittance and haze of the laminated body located outside a metal layer are as follows, respectively.

<Measurement of refractive index>
An Abbe refractometer (NATago NAR-1T SOLID and NAR-1T • LO) was used for the measurement of the refractive index. The refractive index of the base material layer, the adhesive layer (after curing), and the metal layer was measured individually. Moreover, since the coating layer was very thin, it measured after forming the coating layer on the surface of a glass plate.

<Measurement of total light transmittance and haze>
An ultraviolet-visible near-infrared spectrophotometer (V-670 manufactured by JASCO Corporation) was used for measuring the total light transmittance and haze. The total light transmittance and haze of the base material layer and the adhesive layer (after curing) were measured individually. Moreover, it measured after forming the said laminated body about the laminated body (a coating layer, a base material layer, an adhesive layer) located outside a metal layer. Since the thickness of the coating layer was extremely thin, measurement was performed after the coating layer was formed on the surface of the glass plate.

[Manufacture of battery packaging materials]
<Examples 1 to 11 and Comparative Examples 1 to 6>
A metal layer (thickness: 40 μm) subjected to chemical conversion treatment on both surfaces on the base material layer 1 (thickness: 25 μm, and in order of PET layer / nylon layer, 12 μm / 15 μm) made of the resin shown in Table 1 and Table 2. The metal layer 3 made of) was laminated by a dry lamination method. Specifically, a two-component curable urethane adhesive (a polyol compound and an aromatic isocyanate compound) is applied to one side of the metal layer having the glossiness shown in Tables 1 and 2, respectively. Adhesive layer 2 (thickness 4 μm) was formed. Subsequently, after bonding the adhesive layer 2 and the base material layer 1 on the metal layer 3, a laminate of the base material layer 1 / adhesive layer 2 / metal layer 3 is performed by performing an aging treatment at 40 ° C. for 24 hours. Was prepared. In addition, the chemical conversion treatment of the metal layer used as the metal layer 3 is performed by rolling a treatment liquid composed of a phenol resin, a chromium fluoride compound, and phosphoric acid so that the coating amount of chromium is 10 mg / m ² (dry weight). The coating was applied to both surfaces of the metal layer and baked for 20 seconds under the condition that the film temperature was 180 ° C. or higher.

Next, a resin component for forming the heat-welding resin layer 4 shown in Tables 1 and 2 is coextruded in a molten state (250 ° C.) on the metal layer 3 side of the laminate (metal layer side and battery element side). By doing so, the heat-welding resin layer 4 (thickness 22.5 μm on the metal layer side, thickness 22.5 μm on the battery element side) was laminated on the metal layer 3. Thus, a band-shaped battery packaging material comprising a laminated film in which the base material layer 1 / adhesive layer 2 / metal layer 3 / heat-weldable resin layer 4 were laminated in order was obtained.

For the battery packaging materials of Examples 6 to 8 and Comparative Example 5 in Table 2, coating liquids a to d for forming a decorative ink layer based on an acrylic resin are applied on the base layer 1. Then, a decorative ink layer 6 (thickness: 1.0 μm) was formed, and for the battery, similar to Example 1, except that the metal layer 3 was laminated on the formed decorative ink layer 6 by the dry lamination method. A packaging material was produced. As the decorative ink layer forming coating solution, the coating solution a was used in Examples 6 and 7, the coating solution b was used in Example 8, and the coating solution c was used in Comparative Example 5, respectively.

(Coating liquid a for decorative ink layer formation)
Aluminum vapor-deposited foil strips (average thickness 0.06 μm, average major axis 12.2 μm, aspect ratio 203) 30% by mass in the total solid content

(Coating liquid b for decorative ink layer formation)
Aluminum vapor-deposited foil strips (average thickness 0.06 μm, average major axis 12.2 μm, aspect ratio 203) Concentration in total solids 40% by mass

(Coating liquid c for decorative ink layer formation)
Aluminum evaporated foil strips (average thickness 0.06 μm, average major axis 12.2 μm, aspect ratio 203) 10% by mass in the total solid content

Moreover, about the battery packaging material in which the adhesive layer in Table 2 contains aluminum vapor-deposited foil strips, as an adhesive for forming the adhesive layer, the aluminum vapor-deposited foil with respect to the two-component curable urethane adhesive of Example 1 Strips (average thickness 0.06 μm, average major axis 12.2 μm, aspect ratio 203), respectively, a concentration in the total solid content of 30% by mass (Examples 9 and 10) and a concentration in the total solid content of 40% by mass (implementation) Example 11) A battery packaging material was produced in the same manner as in Example 1, except that the added solid adhesive was 10% by mass (Comparative Example 6).

<Measurement of gloss of laminated film and metal layer>
The glossiness of the laminated film surface of the battery packaging material obtained in each Example and Comparative Example, and the glossiness of the metal layer surface used for the production of the laminated film were measured as follows. According to JIS Z 8105, by using BYK-Gardner microtrigloss, the condition of a light incident angle of 60 ° with respect to the surface of the base film 1 side of the laminated film or metal layer was used, and the observed Gu value was defined as the glossiness. . The glossiness of the metal layer surface was measured after the chemical conversion treatment and before laminating other layers such as a base material layer, a heat-welding resin layer, and an adhesive layer. The glossiness of the surface of the laminated film and metal layer used in each of the examples and comparative examples is as shown in Tables 1 and 2, respectively. The glossiness on the base material layer side of the laminated film is affected by not only the glossiness of the metal layer but also the composition and thickness of the base material layer, the decorative ink layer, the adhesive layer, and the like.

<Evaluation of foreign object detection accuracy>
The base material layer side of the battery packaging materials obtained in Examples 1 to 11 and Comparative Examples 1 to 6 continuously produced on the same day was measured with a line scan camera XG-HL04M manufactured by Keyence Corporation at 40 MT / min. Foreign matter defects were measured while being conveyed. The foreign substance recognition was evaluated by comparing the number of defects recognized on the surface 100 m ² of the battery packaging material. ◎◎ when 60 or more defects are recognized, ◎ when 50 to 59 or more defects are recognized, ◎ when 49 to 20 are recognized, ○, 19 to 5 when recognized △ When 4 or less were recognized, it was determined as x. The results are shown in Tables 1 and 2. In Examples 6 and 7, although the glossiness is as high as 350, the reason why the foreign matter recognition performance evaluation is “◯” instead of “」 ”is that when the decorative ink layer is provided, the base material layer It is considered that only the foreign matter existing at the interface portion between the base material layer and the decorative ink layer is detected, and the foreign matter existing in the adhesive layer or the like is excluded from the detection target, and the total number of foreign matters to be detected is small.

In Tables 1 and 2, PET means polyethylene terephthalate, and PBT means polybutylene terephthalate. Acid-modified polypropylene and acid-modified polyethylene are each acid-modified with maleic anhydride.

<Examples 12 to 17>
On the base material layer 1 (thickness 25 μm) made of the resin shown in Table 3, an aluminum foil (metal layer 3) made of a metal layer (thickness 40 μm) subjected to chemical conversion treatment on both surfaces is laminated by a dry lamination method. I let you. Specifically, a two-component curable urethane adhesive (a polyol compound and an aromatic isocyanate compound) is applied to one surface of an aluminum foil having a refractive index shown in Table 3, and an adhesive layer 2 ( A thickness of 3 μm) was formed. Subsequently, after bonding the adhesive layer 2 and the base material layer 1 on the metal layer 3, a laminate of the base material layer 1 / adhesive layer 2 / metal layer 3 is performed by performing an aging treatment at 40 ° C. for 24 hours. Was prepared. In addition, the chemical conversion treatment of the metal layer is performed by a roll coating method using a treatment liquid composed of a phenol resin, a chromium fluoride compound, and phosphoric acid so that the coating amount of chromium is 10 mg / m ² (dry weight). The coating was performed on both surfaces and baked for 20 seconds under the condition that the film temperature was 180 ° C. or higher.

Next, the resin component forming the heat-welding resin layer 4 is coextruded in a molten state (250 ° C.) on the metal layer 3 side of the laminate (the metal layer side is an acid-modified polyolefin resin layer and the battery element side is a polypropylene layer). Thus, a heat-weldable resin layer 4 (thickness 22.5 μm on the metal layer side, thickness 22.5 μm on the battery element side) was laminated on the metal layer 3. Furthermore, in Examples 12 and 13, a trade name “Mesoplus” manufactured by Nippon Kasei Chemical Co., Ltd. was applied to the surface of the base layer by a microgravure method so as to have a thickness of 120 nm. Formed. Thus, in Examples 12 and 13, a belt-shaped battery packaging material comprising a laminated film in which a coating layer / base material layer 1 / adhesive layer 2 / metal layer 3 / heat-weldable resin layer 4 are laminated in order. Obtained. In Examples 14 to 17 and Comparative Example 3, a band-shaped battery packaging material comprising a laminated film in which a base layer 1 / adhesive layer 2 / metal layer 3 / heat-weldable resin layer 4 are laminated in order is obtained. It was. In the same manner as in Examples 1 to 11 and Comparative Examples 1 to 6, the glossiness of the laminated film and the metal layer was measured, and the foreign matter detection accuracy was evaluated. The results are shown in Table 3.

DESCRIPTION OF SYMBOLS 1 Base material layer 2 Adhesive layer 3 Metal layer 4 Hot-weldable resin layer 5 Adhesive layer 6 Decorative ink layer 7 Foreign material

Claims

At least a base film, a metal layer, and a heat-weldable resin layer are laminated films sequentially laminated,
A packaging material for a battery, wherein the glossiness of the surface of the laminated film on the substrate layer side is 150 or more.
The battery packaging material according to claim 1, wherein an adhesive layer is laminated between the base material layer and the metal layer.
A decorative ink layer is laminated between the base material layer and the adhesive layer,
The said decoration ink layer is a packaging material for batteries of Claim 2 currently formed with the resin composition containing a metal thin film strip and binder resin.
The battery packaging material according to claim 2 or 3, wherein the adhesive layer comprises a thin metal film strip.
The battery packaging material according to any one of claims 1 to 4, wherein the metal layer is formed of an aluminum foil or a stainless steel foil.
The battery packaging material according to any one of claims 1 to 5, wherein the base material layer has a thickness of 100 µm or less.
The battery packaging material according to any one of claims 2 to 6, wherein the adhesive layer has a thickness of 20 µm or less.
The battery packaging according to any one of claims 1 to 7, wherein the glossiness of the surface of the laminated film on the substrate layer side is higher than the glossiness of the surface of the laminated film on the heat-weldable resin layer side. material.
The battery packaging material according to any one of claims 1 to 8, wherein a coating layer having a refractive index of 1.20 or more and 1.45 or less is laminated on the opposite side of the base material layer from the metal layer.
The battery packaging material according to any one of claims 1 to 9, wherein a refractive index of the base material layer is 1.49 or more and 1.63 or less.
The battery packaging material according to any one of claims 2 to 10, wherein the adhesive layer has a refractive index of 1.60 or more and 1.72 or less.
The battery packaging material according to any one of claims 1 to 11, wherein the total light transmittance of the laminate composed of all layers located outside the metal layer is 92% or more and haze is 5.0% or less.
The battery packaging material according to any one of claims 1 to 12, wherein the battery packaging material is a wound body of the laminated film.
A battery in which a battery element including at least a positive electrode, a negative electrode, and an electrolyte is accommodated in the battery packaging material according to any one of claims 1 to 13.
At least, a defect inspection method for battery packaging material comprising a laminated film in which a base material layer, a metal layer, and a heat-welding resin layer are laminated in this order,
The surface of the laminated film is imaged on the side opposite to the metal layer of the laminated film, with the laminated film having a glossiness of 150 or more on the surface of the laminated film as a defect inspection target. A step of recording position information of a foreign substance existing between the surface of the metal layer and the surface of the metal layer;
In accordance with the position information, a mark applying step for applying a mark to the laminated film so that the position of the foreign matter can be recognized;
A defect inspection method for battery packaging materials.