Battery packaging material, battery, manufacturing method thereof, and polyester film

Abstract

Provided is a battery packaging material having a polyester film layer on the outermost surface, the surface of which has excellent printability. The laminate is made up of at least a substrate layer located on the outermost surface, a barrier layer, and a heat-sealable resin layer, in this order; the outermost surface of the base material layer is constituted by a polyester film layer, A battery packaging material that satisfies the following formula when infrared absorption spectra are obtained for the surface of the polyester film layer in 18 directions at 10° increments from 0° to 170° using the total reflection method of Fourier transform infrared spectroscopy. Y max / Y min <1.4

Description

[Technical Field]

[0001] The present invention relates to a battery packaging material, a battery, a method for producing the same, and a polyester film. [Background technology]

[0002] Various types of batteries have been developed, but packaging materials are essential components for all batteries to seal battery elements such as electrodes and electrolytes. Conventionally, metal packaging materials have been widely used for battery packaging.

[0003] Meanwhile, in recent years, with the increasing performance of electric vehicles, hybrid electric vehicles, personal computers, cameras, mobile phones, etc., batteries are being required to have a variety of shapes, as well as to be thinner and lighter. However, the metal battery packaging materials that have been widely used up until now have the drawbacks of being difficult to accommodate the diversification of shapes and also having limitations on how light they can be made.

[0004] Therefore, in recent years, a film-like laminate in which a substrate, a barrier layer, and a heat-sealable resin layer are laminated in this order has been proposed as a battery packaging material that can be easily processed into a variety of shapes and can be made thinner and lighter (see, for example, Patent Document 1). In such battery packaging materials, recesses are generally formed by cold forming, and battery elements such as electrodes and electrolyte are placed in the spaces formed by the recesses, and the heat-sealable resin layers are heat-sealed to each other to obtain a battery in which the battery elements are housed inside the battery packaging material.

[0005] In various packaging materials constructed using the above-described laminates, a method of printing on the packaging material (commonly referred to as reverse printing) has been widely adopted, in which ink is printed on the surface of a base layer to form a barcode, pattern, character, or the like, and an adhesive and a barrier layer are then laminated on the printed side of the base layer. However, if such a printed surface exists between the base layer and the barrier layer, the adhesion between the base layer and the barrier layer decreases, making delamination between the layers more likely to occur. In particular, because batteries to which battery packaging materials are applied require high safety, such reverse printing methods have been avoided for battery packaging materials. Therefore, when forming printing such as a barcode on a battery packaging material, a method of attaching a sticker with printing formed thereon to the surface of the base layer has generally been adopted. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Laid-Open No. 2008-287971 Summary of the Invention [Problem to be solved by the invention]

[0007] However, when a sticker with a print formed thereon is attached to the surface of the base layer, the thickness and weight of the battery packaging material increase. Therefore, in consideration of the recent trend toward thinner and lighter battery packaging materials, the present inventors have investigated a method of printing ink directly onto the surface of the base layer of the battery packaging material.

[0008] Known methods for printing ink directly onto the surface of the base layer of a battery packaging material include, for example, pad printing (also called tampo printing) and inkjet printing. Pad printing is a printing method as follows: First, ink is poured into recesses in a flat plate etched with the pattern to be printed. Next, a silicone pad is pressed against the recesses, transferring the ink to the silicone pad. Next, the ink transferred to the surface of the silicone pad is transferred to the printing target, forming a print on the printing target. This type of pad printing has the advantage that, because the ink is transferred to the printing target using an elastic silicone pad or the like, it is easy to print on the surface of the battery packaging material after molding, and printing can be performed on the battery after the battery element has been sealed in the battery packaging material. Inkjet printing also has similar advantages.

[0009] However, the inventors have conducted research and found that when ink is printed on the surface of a battery packaging material having a polyester film layer on the outermost surface, the ink spreads improperly on the surface of the polyester film layer, and the dots formed by the ink tend to have an irregular shape, making it difficult to form prints of the desired size and shape.

[0010] Under these circumstances, a main object of the present invention is to provide a battery packaging material having a polyester film layer on the outermost surface, the polyester film layer having excellent printability on the surface. [Means for solving the problem]

[0011] The present inventors have conducted extensive research to solve the above-mentioned problems, and as a result, have found that a battery packaging material that is composed of a laminate including at least a substrate layer, a barrier layer, and a heat-sealable resin layer located on the outermost surface, in this order, where the outermost surface of the substrate layer is composed of a polyester film layer, and that satisfies the following formula when infrared absorption spectra are obtained for the surface of the polyester film layer in 18 directions at 10-degree intervals from 0° to 170° using the total reflection method of Fourier transform infrared spectroscopy, suppresses inappropriate ink spreading on the surface of the polyester film layer and inhibits distorted dots from being printed, thereby exhibiting excellent printability. Y max / Y min <1.4 Y max In each of the 18 directions, the infrared absorption spectrum wave number is 1340 cm -1 Absorption peak intensity Y at 1340 , wave number 1410cm -1 Absorption peak intensity Y at 1410 It is the maximum value among the values ​​divided by . Y min In each of the 18 directions, the infrared absorption spectrum wave number is 1340 cm -1 Absorption peak intensity Y at 1340 , wave number 1410cm -1 Absorption peak intensity Y at 1410 It is the smallest value among the values ​​divided by Maximum Y max and minimum Y min In the calculation of Y for each of the 18 directions 1340 / Y 1410 From these, the maximum value Y max and minimum Y min Select .

[0012] The present invention was completed based on these findings and through further investigation.

[0013] That is, the present invention provides the following aspects. Item 1. The laminate is composed of at least a substrate layer located on the outermost surface, a barrier layer, and a heat-sealable resin layer in this order, the outermost surface of the base material layer is constituted by a polyester film layer, A battery packaging material that satisfies the following formula when infrared absorption spectra are obtained for the surface of the polyester film layer in 18 directions at 10° increments from 0° to 170° using the total reflection method of Fourier transform infrared spectroscopy. Y max / Y min <1.4 Y max In each of the 18 directions, the infrared absorption spectrum wave number is 1340 cm -1 Absorption peak intensity Y at 1340 , wave number 1410cm -1 Absorption peak intensity Y at 1410 It is the maximum value among the values ​​divided by . Y min In each of the 18 directions, the infrared absorption spectrum wave number is 1340 cm -1 Absorption peak intensity Y at 1340 , wave number 1410cm -1 Absorption peak intensity Y at 1410 It is the smallest value among the values ​​divided by Item 2. The battery packaging material according to Item 1, which is used in applications where printing is performed on the surface of the polyester film layer. Item 3. The battery packaging material according to Item 1 or 2, wherein the arithmetic mean roughness Ra of the surface of the polyester film layer measured in accordance with the method specified in JIS B 0601-2001 is 10 nm or more. Item 4. An adhesive layer is provided between the barrier layer and the heat-sealable resin layer, Item 4. The battery packaging material according to any one of Items 1 to 3, wherein the adhesive layer contains an acid-modified polyolefin. Item 5. The acid-modified polyolefin of the adhesive layer is maleic anhydride-modified polypropylene, Item 5. The battery packaging material according to Item 4, wherein the heat-sealable resin layer contains polypropylene. Item 6. The battery packaging material according to any one of Items 4 and 5, wherein the adhesive layer is a cured product of a resin composition containing at least one compound selected from the group consisting of a compound having an isocyanate group, a compound having an oxazoline group, and a compound having an epoxy group. Item 7. The battery packaging material according to any one of Items 4 to 6, wherein the adhesive layer is a cured product of a resin composition containing a curing agent having at least one selected from the group consisting of an oxygen atom, a heterocycle, a C═N bond, and a COC bond. Item 8. The battery packaging material according to any one of Items 4 to 7, wherein the adhesive layer contains at least one resin selected from the group consisting of urethane resins, ester resins, and epoxy resins. Item 9. The battery packaging material according to any one of Items 4 to 8, wherein the adhesive layer has a thickness of 50 μm or less. Item 10. The battery packaging material according to any one of Items 4 to 8, wherein the adhesive layer has a thickness of 10 μm or more and 50 μm or less. Item 11. The battery packaging material according to any one of Items 4 to 10, which is a co-extruded laminate of the adhesive layer and the heat-sealable resin layer. Item 12. The battery packaging material according to any one of Items 1 to 11, wherein the polyester film layer has a thickness of 10 μm or more and 50 μm or less. Item 13. The battery packaging material according to any one of Items 1 to 12, wherein the polyester film layer is composed of a stretched polyester film. Item 14. The battery packaging material according to any one of Items 1 to 13, wherein when infrared absorption spectra are obtained for the surface of the polyester film layer in 18 directions at 10° increments from 0° to 170° using the total reflection method of Fourier transform infrared spectroscopy, the following formula is satisfied: 1.1≦Y max / Y min <1.4 Item 15. An acid-resistant coating is provided on at least one surface of the barrier layer, When the acid-resistant coating was analyzed using time-of-flight secondary ion mass spectrometry, it was found that CePO 4+ , CePO 4- , CrPO 2+ , and CrPO4- Item 15. The battery packaging material according to any one of Items 1 to 14, wherein a peak derived from at least one selected from the group consisting of: Item 16. The battery packaging material according to any one of Items 1 to 15, wherein at least one surface of the barrier layer is provided with an acid-resistant coating film containing at least one compound selected from the group consisting of phosphorus compounds, chromium compounds, fluorides, and triazine thiol compounds. Item 17. The battery packaging material according to any one of Items 1 to 16, wherein at least one surface of the barrier layer is provided with an acid-resistant coating containing a cerium compound. Item 18. The battery packaging material according to any one of Items 1 to 17, wherein a lubricant is present in at least one of the interior and surface of the polyester film layer. Item 19. A battery, in which a battery element including at least a positive electrode, a negative electrode, and an electrolyte is housed in a package formed from the battery packaging material according to any one of Items 1 to 18. Item 20. The battery according to Item 19, wherein the polyester film layer has a printed portion on its surface. Item 21. A packaging step of housing a battery element including at least a positive electrode, a negative electrode, and an electrolyte in a package made of the battery packaging material according to any one of Items 1 to 18; a step of printing on the surface of the polyester film layer at least either before or after the storing step; A method for manufacturing a battery comprising: Item 22. A polyester film for use in the polyester film layer located on the outermost surface of a battery packaging material, A polyester film that satisfies the following formula when infrared absorption spectra are obtained for the surface of the polyester film in 18 directions at 10° intervals from 0° to 170° using the total reflection method of Fourier transform infrared spectroscopy. Y max / Y min <1.4 Y max In each of the 18 directions, the infrared absorption spectrum wave number is 1340 cm -1 Absorption peak intensity Y at 1340, wave number 1410cm -1 Absorption peak intensity Y at 1410 It is the maximum value among the values ​​divided by . Y min In each of the 18 directions, the infrared absorption spectrum wave number is 1340 cm -1 Absorption peak intensity Y at 1340 , wave number 1410cm -1 Absorption peak intensity Y at 1410 It is the smallest value among the values ​​divided by Item 23. Use of a polyester film that satisfies the following formula when infrared absorption spectra are obtained for the surface of the polyester film in 18 directions at 10° intervals from 0° to 170° using the total reflection method of Fourier transform infrared spectroscopy, as the outermost polyester film layer of a battery packaging material. Y max / Y min <1.4 Y max In each of the 18 directions, the infrared absorption spectrum wave number is 1340 cm -1 Absorption peak intensity Y at 1340 , wave number 1410cm -1 Absorption peak intensity Y at 1410 It is the maximum value among the values ​​divided by . Y min In each of the 18 directions, the infrared absorption spectrum wave number is 1340 cm -1 Absorption peak intensity Y at 1340 , wave number 1410cm -1 Absorption peak intensity Y at 1410 It is the smallest value among the values ​​divided by [Effects of the Invention]

[0014] According to the present invention, it is possible to provide a battery packaging material having a polyester film layer on the outermost surface, in which the surface of the polyester film layer has excellent printability. [Brief explanation of the drawings]

[0015] [Figure 1] 1 is a diagram showing an example of a cross-sectional structure of a battery packaging material of the present invention. [Figure 2] 1 is a diagram showing an example of a cross-sectional structure of a battery packaging material of the present invention. [Figure 3] 1 is a diagram showing an example of a cross-sectional structure of a battery packaging material of the present invention. [Figure 4] 1 is an image of a printed portion formed on the surface of a biaxially stretched polyethylene terephthalate film in Example 2, observed with a laser microscope. [Figure 5] 1 is an image of a printed portion formed on the surface of a biaxially stretched polyethylene terephthalate film in Comparative Example 7, observed with a laser microscope. DETAILED DESCRIPTION OF THE INVENTION

[0016] The battery packaging material of the present invention is composed of a laminate having at least a substrate layer located on the outermost surface, a barrier layer, and a heat-sealable resin layer in this order, the outermost surface of the substrate layer being composed of a polyester film layer, and is characterized in that when infrared absorption spectra are obtained for the surface of the polyester film layer in 18 directions at 10° increments from 0° to 170° using the total reflection method of Fourier transform infrared spectroscopy, the following formula is satisfied: The battery packaging material of the present invention will be described in detail below. Y max / Y min <1.4 In the above formula, Y max In each of the 18 directions, the infrared absorption spectrum wave number is 1340 cm -1 Absorption peak intensity Y at 1340 (CH2 vertical vibration) at a wave number of 1410 cm -1 Absorption peak intensity Y at 1410 It is the maximum value among the values ​​divided by (C=C stretching vibration). Y min In each of the 18 directions, the infrared absorption spectrum wave number is 1340 cm -1 Absorption peak intensity Y at 1340 , wave number 1410cm -1Absorption peak intensity Y at 1410 It is the smallest value among the values ​​divided by Maximum Y max and minimum Y min In the calculation of Y for each of the 18 directions 1340 / Y 1410 From these, the maximum value Y max and minimum Y min Select .

[0017] The battery packaging material of the present invention will be described in detail below. In this specification, numerical ranges indicated with "to" mean "greater than or equal to" or "less than or equal to." For example, the expression "2 to 15 mm" means 2 mm or more and 15 mm or less.

[0018] 1.Layer structure of battery packaging material As shown in Fig. 1, the battery packaging material of the present invention is composed of a laminate including, in this order, a substrate layer 1 located on the outermost surface, a barrier layer 3, and a heat-sealable resin layer 4. The outermost surface of the substrate layer 1 is composed of a polyester film layer. In the battery packaging material of the present invention, the polyester film layer is the outermost layer, and the heat-sealable resin layer 4 is the innermost layer. That is, when assembling a battery, the heat-sealable resin layers 4 located on the periphery of the battery element are heat-sealed to each other to seal the battery element, thereby sealing the battery element.

[0019] As described below, the base layer 1 may include other layers in addition to the polyester film layer. When the base layer 1 includes such other layers, the polyester film layer and the other layers may be bonded to each other by an adhesive layer. Furthermore, as shown in FIG. 2, the battery packaging material of the present invention may optionally include an adhesive layer 2 between the base layer 1 and the barrier layer 3 in order to enhance adhesion therebetween. Furthermore, an adhesive layer 5 may optionally be provided between the barrier layer 3 and the heat-sealable resin layer 4 in order to enhance adhesion therebetween.

[0020] The total thickness of the laminate constituting the battery packaging material of the present invention is not particularly limited, but from the viewpoint of improving formability while making the total thickness of the laminate as thin as possible, it is preferably about 180 μm or less, more preferably about 35 to 160 μm, and even more preferably about 45 to 150 μm.

[0021] The battery packaging material of the present invention is suitable for applications in which printing is performed on the surface of the outermost polyester film layer. Examples of ink printing include the aforementioned pad printing and inkjet printing, with inkjet printing being particularly suitable. Examples of solvents contained in the ink include methyl ethyl ketone, acetone, isopropyl alcohol, and ethanol. The solvents may be used alone or in combination of two or more.

[0022] 2. Layers that form the battery packaging material [Base material layer 1] In the battery packaging material of the present invention, the base layer 1 is the layer located on the outermost surface. The outermost surface of the base layer 1 is composed of a polyester film layer. In the present invention, even when a lubricant is present on the surface of the polyester film layer, the polyester film layer to which the lubricant is attached constitutes the outermost surface of the battery packaging material. Therefore, even in the case of a base layer 1 having a lubricant present on its surface, the base layer 1 is the layer located on the outermost surface of the battery packaging material.

[0023] In the battery packaging material of the present invention, the polyester film layer constituting the outermost surface is characterized in that when infrared absorption spectra are obtained for the surface of the polyester film layer in 18 directions at 10° increments from 0° to 170° using the total reflection method of Fourier transform infrared spectroscopy, the following formula is satisfied: Y max / Y min <1.4 Y max In each of the 18 directions, the infrared absorption spectrum wave number is 1340 cm -1 Absorption peak intensity Y at1340 , wave number 1410cm -1 Absorption peak intensity Y at 1410 It is the maximum value among the values ​​divided by . Also, Y min In each of the 18 directions, the infrared absorption spectrum wave number is 1340 cm -1 Absorption peak intensity Y at 1340 , wave number 1410cm -1 Absorption peak intensity Y at 1410 It is the smallest value among the values ​​divided by Maximum Y max and minimum Y min In the calculation of Y for each of the 18 directions 1340 / Y 1410 From these, the maximum value Y max and minimum Y min Select .

[0024] In the battery packaging material of the present invention, the outermost surface of the base layer is composed of a polyester film layer, and the polyester film layer has the above-mentioned specific surface orientation degree. Therefore, excellent printability is exhibited despite the outermost surface being composed of a polyester film. The mechanism behind this can be considered, for example, as follows. That is, in the battery packaging material of the present invention, the polyester film layer constituting the outermost surface has the above-mentioned specific surface orientation degree, and therefore the degree of orientation of polyester molecules within the polyester film layer is low. Therefore, it is thought that ink easily spreads in a uniform direction on the surface of the polyester film layer, thereby exhibiting excellent printability. In conventional battery packaging materials, when a polyester film layer is used as the base layer, polyester films with a high degree of polyester molecular orientation have been used, for example, by greatly stretching the polyester film, in order to improve formability. However, in the present invention, the polyester film layer constituting the outermost surface has the above-mentioned surface orientation degree, thereby exhibiting excellent printability. There are methods for improving printability by adding a lubricant to the surface of the base layer or by subjecting the base layer to a surface treatment, and these methods can be adopted in the present invention. However, in the present invention, since the polyester film layer has the above-mentioned specific degree of surface orientation, excellent printability is exhibited even though the outermost surface is composed of a polyester film.

[0025] Specific conditions for measuring the infrared absorption spectrum are as follows: The infrared absorption spectrum of the surface of the polyester film layer can be measured in a state where it is laminated on the battery packaging material.

[0026] (Infrared absorption spectrum measurement conditions) Spectrometer (single reflection ATR accessory included) Detector: MCT (Hg Cd Te) Wavenumber resolution: 8cm -1 Number of times accumulated: 128 IRE:Ge Incident angle: 30° Polarizer: Wire grid, S polarization Baseline: Wavenumber 1800-2000cm -1 Average intensity in the range Wave number 1340cm -1 Absorption peak intensity Y at 1340 : Wave number 1335~1342cm -1 The maximum peak intensity in the range minus the baseline value Wave number 1410cm -1 Absorption peak intensity Y at 1410 : Wave number 1400~1410cm -1 The maximum peak intensity in the range minus the baseline value

[0027] To acquire infrared absorption spectra in 18 directions, the sample with the exposed polyester film was placed horizontally on a sample holder and rotated by 10° with the Ge crystal placed on top of the sample. The angle of incidence is the angle between the perpendicular (normal) line and the incident light.

[0028] From the viewpoint of improving the printability of battery packaging materials, the surface orientation degree (Y max / Y min ), the upper limit is less than 1.4. The upper limit is preferably about 1.3 or less, and the lower limit is preferably about 1.0 or more, more preferably about 1.1 or more, and even more preferably about 1.2 or more. Preferred ranges include about 1.0 or more and less than 1.4, about 1.0 to 1.3, about 1.1 or more and less than 1.4, about 1.1 to 1.3, about 1.2 or more and less than 1.4, and about 1.2 to 1.3. The surface orientation degree (Y max / Y min ) is about 1.1 or more, the printability of the battery packaging material can be improved and the moldability can be suitably improved.

[0029] The degree of surface orientation as described above: Y max / Y minThe polyester film having the above formula (1) can be produced by, for example, appropriately adjusting the stretching method, stretching ratio, stretching speed, cooling temperature, heat setting temperature, etc. when producing the polyester film.

[0030] In addition, in the battery packaging material of the present invention, the arithmetic mean roughness Ra of the polyester film layer constituting the outermost surface is, from the viewpoint of improving the printability of the battery packaging material, preferably about 1000 nm or less, more preferably about 500 nm or less, and the lower limit is preferably about 10 nm or more, more preferably about 20 nm or more, with preferred ranges being about 10 to 1000 nm, and about 20 to 500 nm.

[0031] The arithmetic mean roughness Ra of the polyester film layer constituting the outermost surface is a value determined for the surface of the polyester film layer in accordance with the method specified in JIS B 0601-2001. A specific measurement method can be employed as described in the Examples. The arithmetic mean roughness Ra of the polyester film layer can be measured in a state where it is laminated on a battery packaging material.

[0032] The arithmetic mean roughness Ra of the surface of the polyester film layer can be adjusted by the height and density of the irregularities on the surface of the cooling roll used in producing the polyester film. The polyester film layer may also contain additives (such as flame retardants, antiblocking agents, antioxidants, light stabilizers, tackifiers, and antistatic agents) as particles, which can be used to adjust the arithmetic mean roughness Ra. The average particle size of the particles can be, for example, about 0.1 to 5 μm, and the particle content can be, for example, about 0.01 to 0.1% by mass.

[0033] Specific examples of polyesters constituting the polyester film layer include polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polybutylene naphthalate, polyethylene isophthalate, copolymer polyesters whose repeating units are mainly ethylene terephthalate, copolymer polyesters whose repeating units are mainly butylene terephthalate, etc. Specific examples of copolymer polyesters whose repeating units are mainly ethylene terephthalate include copolymer polyesters in which ethylene terephthalate is the main repeating unit and is polymerized with ethylene isophthalate (hereinafter abbreviated as polyethylene (terephthalate / isophthalate)), polyethylene (terephthalate / isophthalate), polyethylene (terephthalate / adipate), polyethylene (terephthalate / sodium sulfoisophthalate), polyethylene (terephthalate / sodium isophthalate), polyethylene (terephthalate / phenyl-dicarboxylate), polyethylene (terephthalate / decanedicarboxylate), etc. Specific examples of copolymer polyesters containing butylene terephthalate as the main repeating unit include copolymer polyesters in which butylene terephthalate is the main repeating unit and is polymerized with butylene isophthalate (hereinafter abbreviated as polybutylene(terephthalate / isophthalate)), polybutylene(terephthalate / adipate), polybutylene(terephthalate / sebacate), polybutylene(terephthalate / decanedicarboxylate), polybutylene naphthalate, etc. These polyesters may be used alone or in combination of two or more. Polyesters have the advantages of excellent heat resistance and electrolyte resistance, and are less likely to cause whitening or other problems when exposed to electrolyte, and are therefore preferably used as materials for forming the base layer 1.

[0034] The polyester film layer may be either a stretched polyester film or an unstretched polyester film, but from the viewpoint of suitably improving the formability of the battery packaging material, it is preferably composed of a stretched polyester film, more preferably a biaxially stretched polyester film, or even more preferably a biaxially stretched polyethylene terephthalate film. Examples of the stretching method include sequential biaxial stretching, inflation, and simultaneous biaxial stretching.

[0035] The thickness of the polyester film layer is not particularly limited, but from the viewpoint of reducing the thickness of the battery packaging material while improving formability, the upper limit is, for example, about 50 μm or less, preferably about 30 μm or less, and more preferably about 25 μm or less, and the lower limit is preferably about 1 μm or more, more preferably about 5 μm or more, and even more preferably about 10 μm or more, and preferred ranges include about 1 to 50 μm, about 1 to 30 μm, about 1 to 25 μm, about 5 to 50 μm, about 5 to 30 μm, about 5 to 25 μm, about 10 to 50 μm, about 10 to 30 μm, and about 10 to 25 μm.

[0036] The polyester film layer may be a single layer or a multi-layer (multi-layer structure). When the polyester film layer is a multi-layer, it is sufficient that at least the polyester film located on the outermost layer side (opposite to the barrier layer 3) satisfies the above-mentioned surface orientation degree, and the other polyester films have a surface orientation degree of Y max / Y min may be 1.4 or more.

[0037] Furthermore, in order to improve the formability of the battery packaging material, the base material layer 1 can also be formed by laminating (forming a multilayer structure) at least one of a resin film and a coating made of a material different from polyester on the barrier layer side of the polyester film layer in addition to the polyester film layer.

[0038] Examples of other resin films that can be used for the base layer 1 include resin films made of polyamide, polyolefin, epoxy resin, acrylic resin, fluororesin, polyurethane, silicone resin, phenolic resin, polyetherimide, polyimide, and mixtures or copolymers thereof. A specific example of a structure in which a polyester film and a resin film made of a different material are laminated is a multilayer structure in which a polyester film layer and a polyamide film layer are laminated.

[0039] Specific examples of polyamide films constituting the polyamide film layer include aliphatic polyamides such as nylon 6, nylon 66, nylon 610, nylon 12, nylon 46, and copolymers of nylon 6 and nylon 6,6; hexamethylenediamine-isophthalic acid-terephthalic acid copolymer polyamides such as nylon 6I, nylon 6T, nylon 6IT, and nylon 6I6T (I represents isophthalic acid, T represents terephthalic acid) containing structural units derived from terephthalic acid and / or isophthalic acid; aromatic polyamides such as polyamide MXD6 (polymetaxylylene adipamide); and alicyclic polyamides such as polyaminomethylcyclohexyl adipamide (PACM6). Further examples include polyamides copolymerized with a lactam component or an isocyanate component such as 4,4'-diphenylmethane diisocyanate, polyesteramide copolymers and polyetheresteramide copolymers, which are copolymers of copolymerized polyamides with polyesters or polyalkylene ether glycols, and polyamide films of these copolymers. These polyamide films may be used alone or in combination of two or more. Polyamide films have excellent stretchability and can prevent whitening due to resin cracking during molding, and are therefore suitable as resin films to be used in the base layer 1 together with polyester films.

[0040] Specific examples of when the base layer 1 has a multilayer structure of polyester film or when the other resin film is included include a laminate of polyester film and nylon film, and a laminate of multiple polyester films, and more preferred are a laminate of stretched polyester film and stretched nylon film, and a laminate of multiple stretched polyester films. For example, when the base layer 1 has a two-layer structure, a laminate of polyester film and polyamide film, or a laminate of polyester film and polyester film is preferred, and a laminate of polyethylene terephthalate and nylon, or a laminate of polyethylene terephthalate and polyethylene terephthalate is more preferred. Furthermore, polyester film is resistant to discoloration, for example, when an electrolyte solution adheres to its surface. In the battery packaging material of the present invention, the polyester film layer forms the outermost surface, thereby achieving a configuration with excellent electrolyte resistance.

[0041] When the base layer 1 has a multilayer structure, the thickness of the polyester film that is not the outermost layer or the resin film other than the polyester film preferably has a lower limit of about 3 μm or more, more preferably about 5 μm or more, and an upper limit of about 30 μm or less, preferably about 25 μm or less, with preferred ranges being about 3 to 30 μm, about 3 to 25 μm, about 5 to 30 μm, and about 5 to 25 μm.

[0042] When the base layer 1 has a multilayer structure, the polyester film and each resin film may be bonded via an adhesive, or may be directly laminated without an adhesive. When bonding without an adhesive, examples include a method of bonding in a hot-melt state, such as co-extrusion, sandwich lamination, or thermal lamination. When bonding via an adhesive, the adhesive used may be a two-component curing adhesive or a one-component curing adhesive. Furthermore, the adhesive mechanism is not particularly limited, and may be any of a chemical reaction type, a solvent volatilization type, a hot-melt type, a thermocompression type, an electron beam curing type, and an ultraviolet curing type. Specific examples of adhesives include those similar to those exemplified for the adhesive layer 2. The thickness of the adhesive may also be the same as that of the adhesive layer 2.

[0043] Furthermore, when the base layer 1 has a multilayer structure, the adhesive for bonding the polyester film and each resin film is preferably a resin composition containing a modified thermoplastic resin graft-modified with an unsaturated carboxylic acid derivative component. The modified thermoplastic resin is preferably a resin obtained by modifying a polyolefin, a styrene-based elastomer, a polyester-based elastomer, or the like with an unsaturated carboxylic acid derivative component. Such resins may be used alone or in combination of two or more. Examples of the unsaturated carboxylic acid derivative component include unsaturated carboxylic acids, acid anhydrides of unsaturated carboxylic acids, and esters of unsaturated carboxylic acids. The unsaturated carboxylic acid derivative component may be used alone or in combination of two or more.

[0044] Examples of polyolefins in modified thermoplastic resins include low-density polyethylene, medium-density polyethylene, and high-density polyethylene; ethylene-α-olefin copolymers; homo-, block-, or random polypropylene; propylene-α-olefin copolymers; copolymers of the above materials with polar molecules such as acrylic acid and methacrylic acid; and polymers such as cross-linked polyolefins. The polyolefins may be used alone or in combination of two or more.

[0045] The styrene-based elastomer in the modified thermoplastic resin includes a copolymer of styrene (hard segment) and butadiene, isoprene, or a hydrogenated product thereof (soft segment). The polyolefin-based resin may be a single type or a combination of two or more types.

[0046] The polyester elastomer in the modified thermoplastic resin may be a copolymer of crystalline polyester (hard segment) and polyalkylene ether glycol (soft segment). The polyolefin may be a single type or a combination of two or more types.

[0047] Examples of unsaturated carboxylic acids in the modified thermoplastic resin include acrylic acid, methacrylic acid, maleic acid, fumaric acid, itaconic acid, citraconic acid, tetrahydrophthalic acid, and bicyclo[2,2,1]hept-2-ene-5,6-dicarboxylic acid. Examples of unsaturated carboxylic acid anhydrides include maleic anhydride, itaconic anhydride, citraconic anhydride, tetrahydrophthalic anhydride, and bicyclo[2,2,1]hept-2-ene-5,6-dicarboxylic acid anhydride. Examples of unsaturated carboxylic acid esters include methyl acrylate, methyl methacrylate, ethyl methacrylate, butyl methacrylate, dimethyl maleate, monomethyl maleate, diethyl fumarate, dimethyl itaconate, diethyl citraconic acid, dimethyl tetrahydrophthalic anhydride, and dimethyl bicyclo[2,2,1]hept-2-ene-5,6-dicarboxylate.

[0048] The modified thermoplastic resin can be obtained by heating and reacting about 0.2 to 100 parts by mass of the unsaturated carboxylic acid derivative component with 100 parts by mass of a base thermoplastic resin in the presence of a radical initiator.

[0049] The reaction temperature is preferably about 50 to 250°C, more preferably about 60 to 200°C. The reaction time depends on the production method, but in the case of a melt grafting reaction using a twin-screw extruder, it is preferably about 2 to 30 minutes, which is within the residence time of the extruder, more preferably about 5 to 10 minutes. The modification reaction can be carried out under either normal pressure or pressurized conditions.

[0050] The radical initiator used in the modification reaction includes organic peroxides. Various organic peroxides can be selected depending on the temperature conditions and reaction time, and examples thereof include alkyl peroxides, aryl peroxides, acyl peroxides, ketone peroxides, peroxyketals, peroxycarbonates, peroxyesters, and hydroperoxides. In the case of the melt grafting reaction using the twin-screw extruder described above, alkyl peroxides, peroxyketals, and peroxyesters are preferred, and di-t-butyl peroxide, 2,5-dimethyl-2,5-di-t-butylperoxyhexyne-3, and dicumyl peroxide are more preferred.

[0051] When the base layer 1 has a multilayer structure, the thickness of the adhesive layer located between the polyester film or each resin film is preferably about 0.1 to 5 μm, more preferably about 0.5 to 3 μm. The adhesive layer may contain the same colorant as the adhesive layer 2 described below.

[0052] In the present invention, from the viewpoint of improving the formability of the battery packaging material, it is preferable that a lubricant be present in at least one of the interior and surface of the polyester film layer. That is, the lubricant may be contained in the polyester film layer, or the lubricant may be present on the surface of the battery packaging material. Furthermore, the lubricant present on the surface of the polyester film layer may be a lubricant exuded from the polyester film layer, or a lubricant applied to the surface of the polyester film layer.

[0053] The lubricant is not particularly limited, but preferred examples include amide-based lubricants and silicone-based lubricants. Specific examples of lubricants include saturated fatty acid amides, unsaturated fatty acid amides, substituted amides, methylolamides, saturated fatty acid bisamides, unsaturated fatty acid bisamides, fatty acid ester amides, and aromatic bisamides. Specific examples of saturated fatty acid amides 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 substituted amides include N-oleyl palmitic 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 methylolamides include methylol stearic acid amide. Specific examples of saturated fatty acid bisamides include methylene bisstearic acid amide, ethylene biscapric acid amide, ethylene bislauric acid amide, ethylene bisstearic acid amide, ethylene bishydroxystearic acid amide, ethylene bisbehenic acid amide, hexamethylene bisstearic acid amide, hexamethylene bisbehenic acid amide, hexamethylene hydroxystearic acid amide, N,N'-distearyl adipamide, and N,N'-distearyl sebacic acid amide. Specific examples of unsaturated fatty acid bisamides include ethylene bisoleic acid amide, ethylene biserucic acid amide, hexamethylene bisoleic acid amide, N,N'-dioleyl adipamide, and N,N'-dioleyl sebacic acid amide. Specific examples of fatty acid ester amides include stearamidoethyl stearate. Specific examples of aromatic bisamides include m-xylylene bisstearic acid amide, m-xylylene bishydroxystearic acid amide, N,N'-distearylisophthalic acid amide, etc. Preferred silicone-based lubricants are non-reactive modified silicone oils such as alkyl-modified silicone oils, higher fatty acid ester-modified silicone oils, and polyether-modified silicone oils.The lubricant may be used alone or in combination of two or more.

[0054] When a lubricant is present on the surface of the polyester film layer, the amount of the lubricant is not particularly limited, but from the viewpoint of exhibiting excellent printability, it is preferably about 3 mg / m 2 or more, more preferably 3 to 15 mg / m 2 approximately, more preferably 4 to 14 mg / m 2 Even when a lubricant is present on the surface of the polyester film layer, the infrared absorption spectrum can be measured on the surface of the polyester film layer on which the lubricant is present.

[0055] Furthermore, additives such as flame retardants, antiblocking agents, antioxidants, light stabilizers, tackifiers, and antistatic agents may be present in at least one of the interior and surface of the base material layer 1. Only one type of additive may be used, or two or more types may be mixed and used.

[0056] The thickness (total thickness) of the base layer 1 is not particularly limited, but from the viewpoint of reducing the thickness of the battery packaging material while improving formability, the upper limit is, for example, about 50 μm or less, preferably about 40 μm or less, and the lower limit is preferably about 3 μm or more, more preferably about 5 μm or more, and even more preferably about 10 μm or more. Preferred ranges for the thickness of the base layer 1 include about 3 to 50 μm, about 3 to 40 μm, about 5 to 50 μm, about 5 to 40 μm, about 10 to 50 μm, and about 10 to 40 μm.

[0057] [Adhesive layer 2] In the battery packaging material of the present invention, the adhesive layer 2 is a layer that is provided between the base material layer 1 and the barrier layer 3 as needed in order to firmly bond them together.

[0058] The adhesive layer 2 is formed from an adhesive capable of bonding the base material layer 1 and the barrier layer 3. The adhesive used to form the adhesive layer 2 may be a two-component curing adhesive or a one-component curing adhesive. Furthermore, the adhesion mechanism of the adhesive used to form the adhesive layer 2 is not particularly limited, and may be any of a chemical reaction type, a solvent volatilization type, a hot melt type, a hot pressure type, or the like.

[0059] Specific examples of adhesive components that can be used to form the adhesive layer 2 include polyesters such as polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polybutylene naphthalate, polyethylene isophthalate, and copolymer polyesters; polyether-based adhesives; polyurethane adhesives; epoxy resins; phenolic resins; polyamides such as nylon 6, nylon 66, and nylon 12, and copolymer polyamides; polyolefins such as polyolefins, carboxylic acid-modified polyolefins, and metal-modified polyolefins; polyvinyl acetate; cellulose-based adhesives; (meth)acrylic resins; polyimides; polycarbonates; amino resins such as urea resins and melamine resins; rubbers such as chloroprene rubber, nitrile rubber, and styrene-butadiene rubber; and silicone-based resins. These adhesive components may be used alone or in combination of two or more. Among these adhesive components, polyurethane adhesives are preferred.

[0060] The polyurethane adhesive is a polyurethane adhesive containing a base agent containing a polyol component (A) and a curing agent containing a polyisocyanate component (B), wherein the polyol component (A) contains a polyester polyol (A1), and the polyester polyol (A1) is a polyester polyol having a number average molecular weight of 5,000 to 50,000 and composed of a polybasic acid component and a polyhydric alcohol component, and the polybasic acid component contains 45 to 95 mol % of an aromatic polybasic acid component in 100 mol %, and the adhesive layer has a tensile stress of 100 kg / cm at 100% elongation. 2 More than 500kg / cm 2Further, there is also included a polyurethane adhesive for battery packaging materials, which contains a base agent and a polyisocyanate curing agent, wherein the base agent contains a polyol component (A) containing 5 to 50 wt % of a polyester polyol (A1) having a glass transition temperature of 40°C or higher and 95 to 50 wt % of a polyester polyol (A2) having a glass transition temperature of less than 40°C, and a silane coupling agent (B), and the equivalent ratio [NCO] / ([OH]+[COOH]) of the isocyanate groups contained in the curing agent to the total of the hydroxyl groups and carboxyl groups derived from the polyol component (A) is 1 to 30.

[0061] Further examples include adhesives containing one or more resins (A) selected from the group consisting of modified polypropylene and acrylic resins, or a resin containing either ((A) or (B)) a coupling agent (B) containing at least one of a silane coupling agent and a titanate-based coupling agent.

[0062] The adhesive layer 2 may also contain a colorant. When the adhesive layer 2 contains a colorant, the battery packaging material can be colored. Known colorants such as pigments and dyes can be used. Only one type of colorant may be used, or two or more types may be mixed together.

[0063] For example, specific examples of inorganic pigments include carbon black and titanium oxide. Specific examples of organic pigments include azo pigments, phthalocyanine pigments, and condensed polycyclic pigments. Examples of azo pigments include soluble pigments such as Watching Red and Carmine 6C; insoluble azo pigments such as monoazo yellow, disazo yellow, pyrazolone orange, pyrazolone red, and permanent red. Examples of phthalocyanine pigments include copper phthalocyanine pigments and metal-free phthalocyanine pigments such as blue and green pigments. Examples of condensed polycyclic pigments include dioxazine violet and quinacridone violet. Examples of pigments that can be used include pearl pigments and fluorescent pigments.

[0064] Among colorants, carbon black is preferred in order to give the battery packaging material a black appearance, for example.

[0065] The average particle size of the pigment is not particularly limited and may be, for example, about 0.05 to 5 μm, and preferably about 0.08 to 2 μm. The average particle size of the pigment is the median size measured with a laser diffraction / scattering particle size distribution measuring device.

[0066] The content of the pigment in the adhesive layer 2 is not particularly limited as long as it colors the battery packaging material, and may be, for example, about 5 to 60 mass %.

[0067] The thickness of the adhesive layer 2 is not particularly limited as long as it functions as an adhesive layer, but may be, for example, about 1 to 10 μm, and preferably about 2 to 5 μm.

[0068] [Colored layer] The colored layer is a layer (not shown) that is provided as needed between the base material layer 1 and the adhesive layer 2. By providing the colored layer, the battery packaging material can be colored.

[0069] The colored layer can be formed, for example, by applying an ink containing a colorant to the surface of the base layer 1 or the surface of the barrier layer 3. Known colorants such as pigments and dyes can be used as the colorant. Furthermore, only one type of colorant may be used, or two or more types may be mixed together.

[0070] Specific examples of the colorant contained in the colored layer include the same as those exemplified in the section [Adhesive layer 2].

[0071] [Barrier layer 3] In the battery packaging material, the barrier layer 3 is a layer that not only improves the strength of the battery packaging material but also has the function of preventing water vapor, oxygen, light, and the like from penetrating into the battery. The barrier layer 3 can be formed from a metal foil, a metal vapor-deposited film, an inorganic oxide vapor-deposited film, a carbon-containing inorganic oxide vapor-deposited film, a film provided with these vapor-deposited layers, or the like, and is preferably a layer formed from a metal. Specific examples of metals that constitute the barrier layer 3 include aluminum, stainless steel, and titanium steel, and aluminum or stainless steel is preferred. The barrier layer 3 is preferably formed from a metal foil, and more preferably from an aluminum alloy foil or stainless steel foil.

[0072] From the viewpoint of preventing wrinkles and pinholes from occurring in the barrier layer 3 during the production of the battery packaging material, it is more preferable that the barrier layer be formed from soft aluminum foil such as annealed aluminum (JIS H4160:1994 A8021H-O, JIS H4160:1994 A8079H-O, JIS H4000:2014 A8021P-O, JIS H4000:2014 A8079P-O).

[0073] Examples of the stainless steel foil include austenitic stainless steel foil, ferritic stainless steel foil, etc. The stainless steel foil is preferably made of austenitic stainless steel.

[0074] Specific examples of austenitic stainless steels that can be used to form the stainless steel foil include SUS304, SUS301, and SUS316L, with SUS304 being particularly preferred.

[0075] The thickness of the barrier layer 3 is not particularly limited as long as it functions as a barrier layer against water vapor, etc., but from the viewpoint of reducing the thickness of the battery packaging material, the upper limit is preferably about 85 μm or less, more preferably about 50 μm or less, and even more preferably about 45 μm or less, and the lower limit is preferably about 10 μm or more. The thickness range can be, for example, about 10 to 85 μm, preferably about 10 to 50 μm, and even more preferably about 10 to 45 μm. When the barrier layer 3 is composed of a stainless steel foil, the thickness of the stainless steel foil is preferably about 85 μm or less, more preferably about 50 μm or less, even more preferably about 40 μm or less, even more preferably about 30 μm or less, and particularly preferably about 25 μm or less. The lower limit is about 10 μm or more, and the preferred thickness ranges are about 10 to 85 μm, about 10 to 50 μm, more preferably about 10 to 40 μm, even more preferably about 10 to 30 μm, and even more preferably about 15 to 25 μm.

[0076] Furthermore, it is preferable that at least one surface, preferably both surfaces, of the barrier layer 3 be chemically treated to stabilize adhesion and prevent dissolution and corrosion. Here, chemical conversion treatment refers to a treatment for forming an acid-resistant coating on the surface of the barrier layer. When an acid-resistant coating is formed on the surface of the barrier layer 3 of the present invention, the barrier layer 3 includes the acid-resistant coating. Examples of chemical conversion treatments include chromate treatment using a chromic acid compound such as chromium nitrate, chromium fluoride, chromium sulfate, chromium acetate, chromium oxalate, chromium biphosphate, chromate acetylacetate, chromium chloride, or potassium chromium sulfate; phosphate chromate treatment using a phosphoric acid compound such as sodium phosphate, potassium phosphate, ammonium phosphate, or polyphosphoric acid; and chromate treatment using an aminated phenol polymer having repeating units represented by the following general formulas (1) to (4). The aminated phenol polymer may contain one type of repeating unit represented by the following general formulas (1) to (4) alone or in any combination of two or more types.

[0077] [ka]

[0078] [ka]

[0079] [ka]

[0080] [ka]

[0081] In the general formulas (1) to (4), X represents a hydrogen atom, a hydroxy group, an alkyl group, a hydroxyalkyl group, an allyl group, or a benzyl group. 1 and R 2 are the same or different and represent a hydroxy group, an alkyl group, or a hydroxyalkyl group. 1 and R 2 Examples of the alkyl group represented by X and R include linear or branched alkyl groups having 1 to 4 carbon atoms, such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, and tert-butyl. 1 and R 2 Examples of the hydroxyalkyl group represented by the formula (1) include a linear or branched alkyl group having 1 to 4 carbon atoms substituted with one hydroxy group, such as a hydroxymethyl group, a 1-hydroxyethyl group, a 2-hydroxyethyl group, a 1-hydroxypropyl group, a 2-hydroxypropyl group, a 3-hydroxypropyl group, a 1-hydroxybutyl group, a 2-hydroxybutyl group, a 3-hydroxybutyl group, and a 4-hydroxybutyl group. 1 and R 2The alkyl groups and hydroxyalkyl groups represented by the general formulae (1) to (4) may be the same or different. In the general formulae (1) to (4), X is preferably a hydrogen atom, a hydroxy group, or a hydroxyalkyl group. The number average molecular weight of the aminated phenol polymer having repeating units represented by the general formulae (1) to (4) is, for example, preferably 500 to 1,000,000, and more preferably 1,000 to 20,000.

[0082] Another example of a chemical conversion treatment method for imparting corrosion resistance to the barrier layer 3 is to coat the surface of the barrier layer 3 with a dispersion of fine particles of metal oxides such as aluminum oxide, titanium oxide, cerium oxide, and tin oxide, or barium sulfate, in phosphoric acid, followed by baking at 150°C or higher to form an acid-resistant coating on the surface of the barrier layer 3. A resin layer in which a cationic polymer is crosslinked with a crosslinking agent may be further formed on the acid-resistant coating. Examples of cationic polymers include polyethyleneimine, ionic polymer complexes composed of a polymer having polyethyleneimine and a carboxylic acid, primary amine-grafted acrylic resins in which a primary amine is graft-polymerized onto an acrylic main skeleton, polyallylamine or its derivatives, and aminophenol. These cationic polymers may be used alone or in combination of two or more. Examples of crosslinking agents include compounds 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 silane coupling agents. These crosslinking agents may be used alone or in combination of two or more.

[0083] As a specific method for providing an acid-resistant coating, for example, at least the inner surface of the aluminum foil (barrier layer) is first degreased using a well-known method such as alkaline immersion, electrolytic cleaning, acid pickling, electrolytic pickling, or acid activation, and then the degreased surface is coated with a treatment solution (aqueous solution) mainly composed of a metal phosphate such as chromium (Cr) phosphate, titanium (Ti) phosphate, zirconium (Zr) phosphate, or zinc (Zn) phosphate, or a mixture of these metal salts, or a treatment solution (aqueous solution) mainly composed of a non-metal phosphate and a mixture of these non-metal salts, or a treatment solution (aqueous solution) composed of a mixture of these with an aqueous synthetic resin such as an acrylic resin, a phenolic resin, or a polyurethane, by a well-known coating method such as roll coating, gravure printing, or immersion to form an acid-resistant coating. For example, when treated with a chromium (Cr) phosphate treatment solution, the acid-resistant coating is formed by coating chromium phosphate (CrPO4), aluminum phosphate (AlPO4), aluminum oxide (Al2O3), Al(OH), etc. x (aluminum hydroxide), AlF x When treated with a zinc phosphate (Zn) salt-based treatment solution, the resulting film is acid-resistant and consists of Zn2PO4·4H2O (hydrated zinc phosphate), AlPO4 (aluminum phosphate), Al2O3 (aluminum oxide), and Al(OH) x (aluminum hydroxide), AlF x It becomes an acid-resistant coating made of aluminum fluoride and other materials.

[0084] Another example of a specific method for providing an acid-resistant coating is to first degrease at least the inner layer surface of the aluminum foil using a known method such as alkali immersion, electrolytic cleaning, acid pickling, electrolytic acid cleaning, or acid activation, and then subject the degreased surface to a known anodizing treatment, thereby forming an acid-resistant coating.

[0085] Other examples of acid-resistant coatings include coatings of phosphorus compounds (e.g., phosphate-based) and chromium compounds (chromate-based). Phosphate-based coatings include zinc phosphate, iron phosphate, manganese phosphate, calcium phosphate, and chromium phosphate, while chromate-based coatings include chromium chromate.

[0086] Other examples of acid-resistant coatings include those made from phosphates, chromates, fluorides, and triazine thiol compounds. These coatings prevent delamination between the aluminum and the base layer during embossing, and prevent dissolution and corrosion of the aluminum surface, particularly of aluminum oxide present on the surface, due to hydrogen fluoride produced by the reaction of electrolytes with water. They also improve the adhesion (wettability) of the aluminum surface, preventing delamination between the base layer and aluminum during heat sealing and, in the case of embossed types, during press molding. Among the substances that form acid-resistant coatings, an aqueous solution composed of three components—phenolic resin, chromium fluoride (III) compound, and phosphoric acid—is effective when applied to the aluminum surface and then dried and baked.

[0087] The acid-resistant coating may include a layer having cerium oxide, phosphoric acid or a phosphate, an anionic polymer, and a crosslinking agent that crosslinks the anionic polymer, and the phosphoric acid or phosphate may be blended in an amount of 1 to 100 parts by mass per 100 parts by mass of the cerium oxide. Preferably, the acid-resistant coating has a multilayer structure that further includes a layer having a cationic polymer and a crosslinking agent that crosslinks the cationic polymer.

[0088] Furthermore, the anionic polymer is preferably poly(meth)acrylic acid or its salt, or a copolymer mainly composed of (meth)acrylic acid or its salt, and the crosslinking agent is preferably at least one selected from the group consisting of a compound having any one of a functional group of an isocyanate group, a glycidyl group, a carboxyl group, and an oxazoline group, and a silane coupling agent.

[0089] The phosphoric acid or phosphate is preferably a condensed phosphoric acid or a condensed phosphate.

[0090] The chemical conversion treatment may be performed using only one type of chemical conversion treatment, or two or more types of chemical conversion treatments in combination. Furthermore, these chemical conversion treatments may be performed using one type of compound alone, or two or more types of compounds in combination. Among the chemical conversion treatments, a chromate treatment or a chromate treatment combining a chromic acid compound, a phosphoric acid compound, and an aminated phenol polymer is preferred.

[0091] Specific examples of acid-resistant coatings include those containing at least one of phosphorus compounds (phosphates, etc.), chromium compounds (chromates), fluorides, and triazine thiol compounds. Acid-resistant coatings containing cerium compounds are also preferred. As the cerium compound, cerium oxide is preferred.

[0092] Specific examples of the acid-resistant coating include phosphate-based coatings, chromate-based coatings, fluoride-based coatings, and triazine thiol compound coatings. The acid-resistant coating may be one of these, or a combination of two or more. Furthermore, the acid-resistant coating may be formed after degreasing the chemically treated surface of the barrier layer, using a treatment liquid consisting of a mixture of a metal phosphate and an aqueous synthetic resin, or a treatment liquid consisting of a mixture of a non-metal phosphate and an aqueous synthetic resin.

[0093] The composition of the acid-resistant coating can be analyzed, for example, by using time-of-flight secondary ion mass spectrometry. By analyzing the composition of the acid-resistant coating using time-of-flight secondary ion mass spectrometry, for example, secondary ions consisting of Ce, P, and O (e.g., Ce2PO4 + , CePO4 - At least one of the following ions may be present: Cr, P, and O secondary ions (e.g., CrPO2 + , CrPO4 - Peaks derived from at least one of the above are detected.

[0094] The amount of the acid-resistant film formed on the surface of the barrier layer 3 in the chemical conversion treatment is not particularly limited. For example, in the case of the above-mentioned chromate treatment, the amount of the acid-resistant film formed on the surface of the barrier layer 3 is 2 It is desirable that the chromate compound is contained in an amount of about 0.5 to 50 mg, preferably about 1.0 to 40 mg, calculated as chromium, the phosphorus compound is contained in an amount of about 0.5 to 50 mg, preferably about 1.0 to 40 mg, calculated as phosphorus, and the aminated phenol polymer is contained in an amount of about 1.0 to 200 mg, preferably about 5.0 to 150 mg, calculated as phosphorus, per unit area.

[0095] The thickness of the acid-resistant coating is not particularly limited, but is preferably about 1 nm to 20 μm, more preferably about 1 to 100 nm, and even more preferably about 1 to 50 nm, from the viewpoint of the cohesive strength of the coating and the adhesive strength with the barrier layer and the heat-sealable resin layer. The thickness of the acid-resistant coating can be measured by observation with a transmission electron microscope, or by a combination of observation with a transmission electron microscope and energy dispersive X-ray spectroscopy or electron energy loss spectroscopy.

[0096] The chemical conversion treatment is carried out by applying a solution containing a compound used to form the acid-resistant coating to the surface of the barrier layer by bar coating, roll coating, gravure coating, immersion, or other methods, and then heating the barrier layer to a temperature of 70 to 200°C. Before the chemical conversion treatment is carried out on the barrier layer, the barrier layer may be subjected to a degreasing treatment using an alkali immersion method, electrolytic cleaning, acid cleaning, electrolytic acid cleaning, or other methods. By carrying out such a degreasing treatment, the chemical conversion treatment on the surface of the barrier layer can be carried out more efficiently.

[0097] [Thermal adhesive resin layer 4] In the battery packaging material of the present invention, the heat-sealable resin layer 4 corresponds to the innermost layer, and is a layer that seals the battery element by heat-sealing the heat-sealable resin layers together during battery assembly.

[0098] The resin component used in the heat-sealable resin layer 4 is not particularly limited as long as it is heat-sealable, and examples thereof include polyolefin, cyclic polyolefin, carboxylic acid-modified polyolefin, and carboxylic acid-modified cyclic polyolefin. That is, the resin constituting the heat-sealable resin layer 4 may or may not contain a polyolefin skeleton, but preferably contains a polyolefin skeleton. Whether the resin constituting the heat-sealable resin layer 4 contains a polyolefin skeleton can be determined by, for example, infrared spectroscopy, gas chromatography mass spectrometry, or the like, and the analysis method is not particularly limited. For example, when maleic anhydride-modified polyolefin is measured by infrared spectroscopy, it is found that the polyolefin skeleton is present at a wave number of 1760 cm. -1 Near and wave number 1780cm -1 A peak derived from maleic anhydride is detected around this point. However, if the degree of acid modification is low, the peak may be small and not be detected. In this case, analysis can be performed using nuclear magnetic resonance spectroscopy.

[0099] Specific examples of the polyolefin include polyethylenes such as low-density polyethylene, medium-density polyethylene, high-density polyethylene, and linear low-density polyethylene; polypropylenes such as homopolypropylene, block copolymers of polypropylene (e.g., block copolymers of propylene and ethylene), and random copolymers of polypropylene (e.g., random copolymers of propylene and ethylene); and ethylene-butene-propylene terpolymers. Among these polyolefins, polyethylene and polypropylene are preferred.

[0100] The cyclic polyolefin is a copolymer of an olefin and a cyclic monomer, and examples of the olefin constituting the cyclic polyolefin include ethylene, propylene, 4-methyl-1-pentene, butadiene, and isoprene. Examples of the cyclic monomer constituting the cyclic polyolefin include cyclic alkenes such as norbornene; specifically, cyclic dienes such as cyclopentadiene, dicyclopentadiene, cyclohexadiene, and norbornadiene. Among these polyolefins, preferred are cyclic alkenes, and more preferably norbornene. Styrene can also be used as a constituting monomer.

[0101] The carboxylic acid-modified polyolefin is a polymer obtained by modifying the polyolefin by 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.

[0102] The carboxylic acid-modified cyclic polyolefin is a polymer obtained by copolymerizing a cyclic polyolefin by replacing a portion of the monomers constituting the cyclic polyolefin with an α,β-unsaturated carboxylic acid or its anhydride, or by block or graft polymerizing a cyclic polyolefin with an α,β-unsaturated carboxylic acid or its anhydride. The carboxylic acid-modified cyclic polyolefin is the same as described above. The carboxylic acid used for the modification is the same as that used for the modification of the polyolefin.

[0103] Among these resin components, preferred are carboxylic acid-modified polyolefins, and more preferred are carboxylic acid-modified polypropylenes.

[0104] The thermally adhesive resin layer 4 may be formed of one type of resin component alone, or may be formed of a blend polymer of two or more types of resin components. Furthermore, the thermally adhesive resin layer 4 may be formed of only one layer, or may be formed of two or more layers of the same or different resin components.

[0105] The heat-sealable resin layer 4 may contain a lubricant. The lubricant present on the surface of the heat-sealable resin layer 4 may be a lubricant exuded from the resin constituting the heat-sealable resin layer 4, or a lubricant applied to the surface of the heat-sealable resin layer 4. When the heat-sealable resin layer 4 contains a lubricant, the formability of the battery packaging material can be improved. The lubricant is not particularly limited, and known lubricants can be used, such as those exemplified for the base material layer 1 above. The lubricant may be used alone, or two or more types may be used in combination. The amount of lubricant present on the surface of the heat-sealable resin layer 4 is not particularly limited, and from the viewpoint of improving the formability of the electronic packaging material, it is preferably 10 to 50 mg / m 2 about 15 to 40 mg / m 2 The degree of

[0106] The thickness of the heat-sealable resin layer 4 is not particularly limited as long as it functions as a heat-sealable resin layer, but may be, for example, about 100 μm or less, preferably about 85 μm or less, and more preferably about 15 to 85 μm. For example, when the thickness of the adhesive layer 5 described below is 10 μm or more, the thickness of the heat-sealable resin layer 4 is preferably about 85 μm or less, and more preferably about 15 to 65 μm. For example, when the thickness of the adhesive layer 5 described below is less than 10 μm or when the adhesive layer 5 is not provided, the thickness of the heat-sealable resin layer 4 is preferably about 20 μm or more, and more preferably about 35 to 85 μm.

[0107] [Adhesive layer 5] In the battery packaging material of the present invention, the adhesive layer 5 is a layer that is provided between the barrier layer 3 and the heat-sealable resin layer 4 as needed in order to firmly bond them together.

[0108] The adhesive layer 5 is formed of a resin capable of bonding the barrier layer 3 and the heat-sealable resin layer 4. The resin used to form the adhesive layer 5 can be the same as the adhesive exemplified for the adhesive layer 2 in terms of adhesion mechanism, type of adhesive component, etc. The resin used to form the adhesive layer 5 can also be a polyolefin such as the polyolefin, cyclic polyolefin, carboxylic acid-modified polyolefin, or carboxylic acid-modified cyclic polyolefin exemplified for the heat-sealable resin layer 4. From the viewpoint of excellent adhesion between the barrier layer 3 and the heat-sealable resin layer 4, carboxylic acid-modified polyolefin is preferred, and carboxylic acid-modified polypropylene is particularly preferred. That is, the resin constituting the adhesive layer 5 may or may not contain a polyolefin skeleton, but preferably contains a polyolefin skeleton. The presence of a polyolefin skeleton in the resin constituting the adhesive layer 5 can be determined by, for example, infrared spectroscopy, gas chromatography-mass spectrometry, or the like, and the analysis method is not particularly limited. For example, when maleic anhydride-modified polyolefin is measured by infrared spectroscopy, a peak at a wavenumber of 1760 cm is observed. -1 Near and wave number 1780cm -1 A peak derived from maleic anhydride is detected around this point. However, if the degree of acid modification is low, the peak may be small and not be detected. In this case, analysis can be performed using nuclear magnetic resonance spectroscopy.

[0109] From the viewpoint of improving adhesion between the barrier layer 3 (or acid-resistant coating) and the heat-sealable resin layer 4, the adhesive layer 5 preferably contains an acid-modified polyolefin. An acid-modified polyolefin is a polymer modified by block polymerization or graft polymerization of a polyolefin with an acid component such as a carboxylic acid. Examples of the acid component used for modification include carboxylic acids or anhydrides thereof, such as maleic acid, acrylic acid, itaconic acid, crotonic acid, maleic anhydride, and itaconic anhydride. Examples of the polyolefin to be modified include polyethylenes such as low-density polyethylene, medium-density polyethylene, high-density polyethylene, and linear low-density polyethylene; polypropylenes such as homopolypropylene, block copolymers of polypropylene (e.g., block copolymers of propylene and ethylene), and random copolymers of polypropylene (e.g., random copolymers of propylene and ethylene); and ethylene-butene-propylene terpolymers. Among these polyolefins, polyethylene and polypropylene are preferred.

[0110] In the adhesive layer 5, among the acid-modified polyolefins, maleic anhydride-modified polyolefins are particularly preferred, and maleic anhydride-modified polypropylene is even more preferred.

[0111] Furthermore, from the viewpoint of reducing the thickness of the battery packaging material while providing a battery packaging material with excellent shape stability after molding, the adhesive layer 5 is more preferably a cured product of a resin composition containing an acid-modified polyolefin and a curing agent. Preferred examples of the acid-modified polyolefin include those listed above.

[0112] The adhesive layer 5 is preferably a cured product of a resin composition containing an acid-modified polyolefin and at least one selected from the group consisting of a compound having an isocyanate group, a compound having an oxazoline group, and a compound having an epoxy group. It is particularly preferably a cured product of a resin composition containing an acid-modified polyolefin and at least one selected from the group consisting of a compound having an isocyanate group and a compound having an epoxy group. The adhesive layer 5 preferably contains at least one selected from the group consisting of a urethane resin, an ester resin, and an epoxy resin, and more preferably contains a urethane resin and an epoxy resin. An example of a preferred ester resin is an amide ester resin. Amide ester resins are generally produced by the reaction of a carboxyl group with an oxazoline group. The adhesive layer 5 is more preferably a cured product of a resin composition containing at least one of these resins and the acid-modified polyolefin. In addition, if unreacted compounds of curing agents such as compounds having an isocyanate group, compounds having an oxazoline group, and epoxy resins remain in the adhesive layer 5, the presence of the unreacted compounds can be confirmed by a method selected from, for example, infrared spectroscopy, Raman spectroscopy, time-of-flight secondary ion mass spectrometry (TOF-SIMS), etc.

[0113] Furthermore, from the viewpoint of further enhancing the adhesion between the barrier layer 3 (or acid-resistant coating), the heat-sealable resin layer 4, and the adhesive layer 5, the adhesive layer 5 is preferably a cured product of a resin composition containing a curing agent having at least one selected from the group consisting of an oxygen atom, a heterocycle, a C═N bond, and a C═C bond. Examples of curing agents having a heterocycle include curing agents having an oxazoline group and curing agents having an epoxy group. Examples of curing agents having a C═N bond include curing agents having an oxazoline group and curing agents having an isocyanate group. Examples of curing agents having a C═C bond include curing agents having an oxazoline group, curing agents having an epoxy group, and urethane resins. Whether the adhesive layer 5 is a cured product of a resin composition containing such a curing agent can be confirmed by, for example, gas chromatography mass spectrometry (GCMS), infrared spectroscopy (IR), time-of-flight secondary ion mass spectrometry (TOF-SIMS), X-ray photoelectron spectroscopy (XPS), or other methods.

[0114] The compound having an isocyanate group is not particularly limited, but from the viewpoint of effectively increasing the adhesion between the acid-resistant coating and the adhesive layer 5, a polyfunctional isocyanate compound is preferred. The polyfunctional isocyanate compound is not particularly limited as long as it is a compound having two or more isocyanate groups. Specific examples of polyfunctional isocyanate curing agents include pentane diisocyanate (PDI), isophorone diisocyanate (IPDI), hexamethylene diisocyanate (HDI), tolylene diisocyanate (TDI), diphenylmethane diisocyanate (MDI), polymers or nurates thereof, mixtures of these, and copolymers with other polymers.

[0115] The content of the compound having an isocyanate group in the adhesive layer 5 is preferably in the range of 0.1 to 50 mass % in the resin composition constituting the adhesive layer 5, and more preferably in the range of 0.5 to 40 mass %.

[0116] The compound having an oxazoline group is not particularly limited as long as it is a compound having an oxazoline skeleton. Specific examples of the compound having an oxazoline group include those having a polystyrene main chain and those having an acrylic main chain. Examples of commercially available products include the Epocross series manufactured by Nippon Shokubai Co., Ltd.

[0117] The proportion of the compound having an oxazoline group in the adhesive layer 5 is preferably in the range of 0.1 to 50 mass %, and more preferably in the range of 0.5 to 40 mass %, in the resin composition constituting the adhesive layer 5. This effectively improves the adhesion between the barrier layer 3 (or acid-resistant film) and the adhesive layer 5.

[0118] The epoxy resin is not particularly limited as long as it is a resin capable of forming a crosslinked structure by the epoxy groups present in the molecule, and known epoxy resins can be used. The weight-average molecular weight of the epoxy resin is preferably about 50 to 2,000, more preferably about 100 to 1,000, and even more preferably about 200 to 800. In the present invention, the weight-average molecular weight of the epoxy resin is a value measured by gel permeation chromatography (GPC) under conditions using polystyrene as a standard sample.

[0119] Specific examples of epoxy resins include glycidyl ether derivatives of trimethylolpropane, bisphenol A diglycidyl ether, modified bisphenol A diglycidyl ether, novolac glycidyl ether, glycerin polyglycidyl ether, polyglycerin polyglycidyl ether, etc. One type of epoxy resin may be used alone, or two or more types may be used in combination.

[0120] The proportion of the epoxy resin in the adhesive layer 5 is preferably in the range of 0.1 to 50 mass %, and more preferably in the range of 0.5 to 40 mass %, of the resin composition constituting the adhesive layer 5. This effectively improves the adhesion between the barrier layer 3 (or acid-resistant film) and the adhesive layer 5.

[0121] In the present invention, when the adhesive layer 5 is a cured product of a resin composition containing at least one selected from the group consisting of a compound having an isocyanate group, a compound having an oxazoline group, and an epoxy resin, and the acid-modified polyolefin, the acid-modified polyolefin functions as the main agent, and the compound having an isocyanate group, the compound having an oxazoline group, and the epoxy resin each function as a curing agent.

[0122] The carbodiimide curing agent is not particularly limited as long as it is a compound having at least one carbodiimide group (-N=C=N-). As the carbodiimide curing agent, a polycarbodiimide compound having at least two carbodiimide groups is preferred.

[0123] From the viewpoint of improving the adhesion between the barrier layer 3 and the thermally adhesive resin layer 4 by the adhesive layer 5, the curing agent may be composed of two or more types of compounds.

[0124] The content of the curing agent in the resin composition forming the adhesive layer 5 is preferably in the range of approximately 0.1 to 50 mass%, more preferably in the range of approximately 0.1 to 30 mass%, and even more preferably in the range of approximately 0.1 to 10 mass%.

[0125] Furthermore, the adhesive layer 5 can also be suitably formed using, for example, an adhesive. Examples of the adhesive include an adhesive formed from an adhesive composition containing a non-crystalline polyolefin resin (A) having a carboxyl group, a polyfunctional isocyanate compound (B), and a tertiary amine (C) having no functional group reactive with the polyfunctional isocyanate compound (B), wherein the amount of isocyanate groups in the polyfunctional isocyanate compound (B) is in the range of 0.3 to 10 moles per mole of carboxyl groups in total, and the amount of tertiary amine (C) is in the range of 1 to 10 moles per mole of carboxyl groups in total. Further, examples of the adhesive include an adhesive composition comprising a styrene-based thermoplastic elastomer (A), a tackifier (B), and a polyisocyanate (C), in which the styrene-based thermoplastic elastomer (A) and the tackifier (B) total 100% by weight, and the styrene-based thermoplastic elastomer (A) comprises 20 to 90% by weight and the tackifier (B) comprises 10 to 80% by weight, the styrene-based thermoplastic elastomer (A) has 0.003 to 0.04 mmol / g of active hydrogen derived from amino groups or hydroxyl groups, the active hydrogen derived from functional groups of the tackifier (B) is 0 to 15 moles per mole of the active hydrogen derived from the styrene-based thermoplastic elastomer (A), and the polyisocyanate (C) contains 3 to 150 moles of isocyanate groups per mole of the total of the active hydrogen derived from the styrene-based thermoplastic elastomer (A) and the active hydrogen derived from the tackifier (B).

[0126] The thickness of adhesive layer 5 is not particularly limited as long as it functions as an adhesive layer, but may be, for example, about 50 μm or less, about 40 μm or less, preferably about 30 μm or less, more preferably about 20 μm or less, and even more preferably about 5 μm or less. The lower limit may be about 0.1 μm or more, about 0.5 μm or more, or about 10 μm or more. The thickness range is preferably about 0.1 to 50 μm, about 0.1 to 40 μm, about 0.1 to 30 μm, about 0.1 to 20 μm, about 0.1 to 5 μm, about 0.5 to 50 μm, about 0.5 to 40 μm, about 0.5 to 30 μm, about 0.5 to 20 μm, about 0.5 to 5 μm, about 10 to 50 μm, about 10 to 40 μm, about 10 to 30 μm, or about 10 to 20 μm. More specifically, when an adhesive exemplified for the adhesive layer 2 is used, the thickness is preferably about 2 to 10 μm, more preferably about 2 to 5 μm. When a resin exemplified for the heat-fusible resin layer 4 is used, the thickness is preferably about 2 to 50 μm, more preferably about 10 to 40 μm. When a cured product of an acid-modified polyolefin and a curing agent is used, the thickness is preferably about 30 μm or less, more preferably about 0.1 to 20 μm, and even more preferably about 0.5 to 5 μm. When an adhesive layer is formed from the adhesive composition described above, the thickness after drying and curing is 1 to 30 g / m 2 When the adhesive layer 5 is a cured product of a resin composition containing an acid-modified polyolefin and a curing agent, the adhesive layer 5 can be formed by applying the resin composition and curing it by heating or the like.

[0127] As will be described later, in producing the laminate constituting the battery packaging material of the present invention, a method of laminating the adhesive layer 5 and the heat-sealable resin layer 4 in this order on the barrier layer 3 can be employed, in which the adhesive layer 5 and the heat-sealable resin layer 4 are co-extruded onto the barrier layer 3. That is, in the battery packaging material of the present invention, the adhesive layer and the heat-sealable resin layer can be a co-extruded laminate.

[0128] 3. Manufacturing method for battery packaging material The method for producing the battery packaging material of the present invention is not particularly limited as long as it can produce a laminate in which layers of a predetermined composition are laminated. For example, the method for producing the battery packaging material includes a step of obtaining a laminate by laminating at least a substrate layer, a barrier layer, and a heat-sealable resin layer located on the outermost surface in this order, in which the outermost surface of the substrate layer is constituted by a polyester film layer, and the polyester film is used for the total reflection method of Fourier transform infrared spectroscopy, and when infrared absorption spectra are obtained on the surface of the polyester film in 18 directions at 10° intervals from 0° to 180°, the infrared absorption spectrum of the polyester film is obtained by the total reflection method of Fourier transform infrared spectroscopy, and the infrared absorption spectrum of the polyester film is obtained by the total reflection method of -1 Absorption peak intensity Y at 1340 And 1410cm -1 Absorption peak intensity Y at 1410 Ratio to (Y 1340 / Y 1410 ) maximum value Y max and minimum Y min Ratio of surface orientation (Y max / Y min ) is less than 1.4.

[0129] An example of a method for producing the battery packaging material of the present invention is as follows. First, a laminate (hereinafter, sometimes referred to as "laminate A") is formed in which a base layer 1, an adhesive layer 2, and a barrier layer 3 are laminated in this order. Specifically, laminate A can be formed by a dry lamination method in which an adhesive used to form adhesive layer 2 is applied to base layer 1 or to barrier layer 3, the surface of which has been chemically treated as necessary, by a coating method such as gravure coating or roll coating, and dried, and then the barrier layer 3 or base layer 1 is laminated thereon, and the adhesive layer 2 is cured.

[0130] Next, the adhesive layer 5 and the heat-fusible resin layer 4 are laminated in this order on the barrier layer 3 of the laminate A. Examples of such methods include: (1) a method of laminating the adhesive layer 5 and the heat-sealable resin layer 4 on the barrier layer 3 of the laminate A by co-extrusion (co-extrusion lamination method); (2) a method of separately forming a laminate in which the adhesive layer 5 and the heat-sealable resin layer 4 are laminated, and laminating this on the barrier layer 3 of the laminate A by thermal lamination; (3) a method of laminating an adhesive for forming the adhesive layer 5 on the barrier layer 3 of the laminate A by extrusion or solution coating, drying at high temperature, and baking, etc., and laminating a heat-sealable resin layer 4 previously formed into a sheet-like film on this adhesive layer 5 by thermal lamination; and (4) a method of pouring a molten adhesive layer 5 between the barrier layer 3 of the laminate A and the heat-sealable resin layer 4 previously formed into a sheet-like film, and bonding the laminate A and the heat-sealable resin layer 4 together via the adhesive layer 5 (sandwich lamination method).

[0131] As described above, a laminate is formed comprising the base layer 1, the adhesive layer 2 (if necessary), the barrier layer 3 whose surface is chemically treated as necessary, the adhesive layer 5, and the heat-sealable resin layer 4. In order to strengthen the adhesiveness of the adhesive layer 2 or the adhesive layer 5, the laminate may be further subjected to a heat treatment using a hot roll contact method, hot air, near-infrared light, or far-infrared light. Conditions for such heat treatment include, for example, about 150 to 250°C for about 1 to 5 minutes.

[0132] In the battery packaging material of the present invention, each layer constituting the laminate may be subjected to a surface activation treatment such as corona treatment, blast treatment, oxidation treatment, or ozone treatment, as necessary, in order to improve or stabilize film-forming properties, lamination processing, suitability for secondary processing of final products (pouching, embossing), etc.

[0133] 4. Applications of battery packaging materials The battery packaging material of the present invention is used in a package for hermetically housing battery elements such as a positive electrode, a negative electrode, and an electrolyte. That is, a battery can be formed by housing a battery element including at least a positive electrode, a negative electrode, and an electrolyte in a package formed from the battery packaging material of the present invention. The battery packaging material of the present invention is suitably used in applications in which printing is performed on the surface of the outermost polyester film layer.

[0134] Specifically, a battery element including at least a positive electrode, a negative electrode, and an electrolyte is coated with the battery packaging material of the present invention so that a flange portion (a region where the heat-sealable resin layers contact each other) is formed around the periphery of the battery element, with the metal terminals connected to the positive electrode and negative electrode protruding outward, and the heat-sealable resin layers of the flange portion are heat-sealed to form a hermetic seal, thereby providing a battery using the battery packaging material. When a battery element is housed in a package formed from the battery packaging material of the present invention, the package is formed so that the heat-sealable resin portion of the battery packaging material of the present invention faces inward (the surface that contacts the battery element). The infrared absorption spectrum and the arithmetic mean roughness Ra of the surface of the polyester film layer can be measured by obtaining the battery packaging material from a battery and measuring the polyester film layer of the obtained battery packaging material. However, the infrared absorption spectrum and the arithmetic mean roughness Ra of the battery packaging material obtained from the battery are measured on the battery packaging material of a portion other than the peripheral flange (the portion where the heat-sealable resin layers are heat-sealed to each other) or the side portion of the battery (preferably the top or bottom surface of the battery).

[0135] In the present invention, a battery having a printed surface on a polyester film layer can be manufactured by a method including a step of housing a battery element including at least a positive electrode, a negative electrode, and an electrolyte in a package formed from the battery packaging material of the present invention, and a step of printing on the surface of the outermost polyester film layer at least either before or after the housing step. That is, the battery of the present invention can be a battery having a printed portion on its surface. The printed portion is a portion on the surface of the battery where a barcode, pattern, letter, symbol, or the like is printed.

[0136] In the battery packaging material of the present invention, when the printability of the polyethylene terephthalate film surface is evaluated under the following conditions, the radius of the dots forming the printed portion is preferably 130 μm or more, 135 μm or more, 140 μm or more, and 151 μm or less, or 149 μm or less. Preferred ranges for the radius include approximately 130 to 151 μm, 130 to 149 μm, 135 to 151 μm, 135 to 149 μm, 140 to 151 μm, and 140 to 149 μm. When the dot radius satisfies these values, the printability can be evaluated as excellent. Specifically, prints such as barcodes, patterns, letters, and symbols are formed by a collection of ink dots, and when the radius of the dots forming the printed portion satisfies the above-mentioned values, the dot radius is neither too small nor too large, allowing the desired printing to be performed appropriately.

[0137] Furthermore, in the battery packaging material of the present invention, when the printability of the polyethylene terephthalate film surface is evaluated under the following conditions, the circularity of the dots forming the printed portion is preferably 0.725 or more. The closer the circularity of the printed portion is to 1, the more excellent the printability can be evaluated. Specifically, when the circularity of the dots forming the printed portion satisfies the above-mentioned value, the dots will not be distorted and the desired printing can be performed appropriately.

[0138] <Evaluation of printability of polyethylene terephthalate film surface> Ink was applied to the polyethylene terephthalate film surface of each battery packaging material prepared above using an inkjet printer (Markem-Image 9040 (1.1M head)) at a temperature of 24°C and a relative humidity of 50%, and the film was allowed to dry for 10 seconds. The printability of the polyethylene terephthalate film surface was then evaluated based on the radius and circularity of the dots printed on the film surface. The printing conditions were ink viscosity: 3.4 cps, temperature: 34°C, pressure: 270 bar, nozzle size: 50 μm diameter, and resolution (dot density): 115 dpi. The method for measuring the radius and circularity of the printed dots is described below. The evaluation was performed on the battery packaging material. The radius and circularity of the printed dots were the average values ​​for a sample of 3. The evaluation was performed without wiping the surface of the polyethylene terephthalate film.

[0139] The distance between the print head of the inkjet printer and the surface of the polyethylene terephthalate film is 20 mm, and the ink used is 5157E standard ink.

[0140] The radius and circularity of the dots in the printed portion formed on the surface of the polyethylene terephthalate film are observed using a laser microscope (for example, laser microscope VK-9710 manufactured by KEYENCE) at a magnification of 10 times.

[0141] (Method for measuring the radius of printed dots) The shape of the dots in the printed area dropped onto the surface of each polyethylene terephthalate film is analyzed using image analysis software (e.g., KEYENCE analysis software VK Analyzer Ver. 2.4.0.0) on the image observed with the laser microscope, and the radius of the circle passing through the three points (= the radius of the dots in the printed area) is determined by three-point circle analysis.

[0142] (Evaluation of the circularity of printed dots) The circularity of the dots in the printed area formed by ink droplets on the surface of each polyethylene terephthalate film is measured using image analysis software (for example, Mitani Corporation's image analysis software WinROOF (Ver. 6.6.0)). The analysis is performed on the figure connecting the center points of the boundary pixels that make up the outline of the dot. On the WinRoof analysis screen, this value is displayed as circularity II. The circularity of the dots in the printed area is calculated using the following formula: Circularity of printed dots = 4π x (area of ​​dots) / (perimeter of dots) 2

[0143] The battery packaging material of the present invention may be used for either primary batteries or secondary batteries, but is preferably used for secondary batteries. The type of secondary battery to which the battery packaging material of the present invention is applied is not particularly limited, and examples include lithium ion batteries, lithium ion polymer batteries, lead acid batteries, nickel-metal hydride batteries, nickel-cadmium batteries, nickel-iron batteries, nickel-zinc batteries, silver oxide-zinc batteries, metal-air batteries, polyvalent cation batteries, condensers, and capacitors. Among these secondary batteries, lithium ion batteries and lithium ion polymer batteries are preferred applications of the battery packaging material of the present invention.

[0144] 5. Polyester film The polyester film of the present invention is a polyester film used for a polyester film layer located on the outermost surface of a battery packaging material. When infrared absorption spectra are obtained for the surface of the polyester film in 18 directions at 10° intervals from 0° to 170° using the total reflection method of Fourier transform infrared spectroscopy, the polyester film of the present invention has a Y max / Y min<1.4. The specific configuration (composition, thickness, etc.) of the polyester film of the present invention is the same as that of the polyester film layer constituting the outermost surface in "2. Each layer constituting the battery packaging material" above. Note that the measurement of the infrared absorption spectrum of the polyester film surface can be carried out on the polyester film alone, on the surface that will become the outermost surface of the battery packaging material. Furthermore, the measurement of the arithmetic mean roughness Ra of the polyester film can also be carried out on the polyester film alone, on the surface that will become the outermost surface of the battery packaging material. [Example]

[0145] The present invention will be described in detail below with reference to examples and comparative examples, but the present invention is not limited to these examples.

[0146] <Manufacturing of battery packaging materials> The battery packaging materials of Examples 1 to 3 and Comparative Examples 1 to 7 were produced by the following method.

[0147] Example 1 Biaxially stretched polyethylene terephthalate film (thickness 25 μm, surface orientation degree: Y in Table 1) was used as the base layer. max / Y min A barrier layer consisting of aluminum foil (JIS H4160:1994 A8021H-O, thickness 40 μm) with an acid-resistant coating formed on both sides was laminated by dry lamination onto a substrate (having a surface roughness of 1000 nm and an arithmetic mean roughness Ra). Specifically, a two-component curing urethane adhesive (a polyol compound and an aromatic isocyanate compound) was applied to one side of the aluminum foil, forming an adhesive layer (thickness 3 μm) on the aluminum foil with the acid-resistant coating formed on both sides. Next, the adhesive layer on the aluminum foil and a biaxially oriented polyethylene terephthalate film were laminated, and then an aging treatment was performed to produce a substrate layer / adhesive layer / barrier layer laminate. The chemical conversion treatment to form an acid-resistant coating on the aluminum foil used as the barrier layer was performed using a treatment solution consisting of a phenolic resin, a chromium fluoride compound, and phosphoric acid, with a coating amount of chromium of 10 mg / m2 The coating was applied to both sides of an aluminum foil by roll coating so that the dry weight was 100g, and then baked. The aluminum foil used as the barrier layer had an acid-resistant coating containing chromium oxide and phosphate.

[0148] Next, maleic anhydride-modified polypropylene (thickness: 25 μm) as an adhesive layer and random polypropylene (thickness: 55 μm) as a heat-sealable resin layer were co-extruded onto the barrier layer of the obtained laminate, thereby laminating an adhesive layer / heat-sealable resin layer on the barrier layer. Next, the obtained laminate was aged and heated to obtain a battery packaging material in which a base layer / adhesive layer / barrier layer with acid-resistant coatings on both sides / adhesive layer / heat-sealable resin layer were laminated in this order.

[0149] The analysis of the acid-resistant coating was carried out as follows. First, the barrier layer and the adhesive layer were peeled off. This was done physically, without using water, organic solvents, or aqueous solutions of acids or alkalis. After the barrier layer and the adhesive layer were peeled off, the adhesive layer remained on the surface of the barrier layer, so this was removed by etching with Ar-GCIB. The surface of the barrier layer obtained in this way was analyzed for the acid-resistant coating using time-of-flight secondary ion mass spectrometry. As a result, Ce2PO4 + , CePO4 - Secondary ions consisting of Ce, P, and O were detected. Details of the measurement equipment and conditions for time-of-flight secondary ion mass spectrometry are as follows:

[0150] Measurement equipment: ION-TOF time-of-flight secondary ion mass spectrometer TOF.SIMS5 Measurement conditions Primary ion: Bismuth cluster doubly charged ion (Bi3 ++ ) Primary ion accelerating voltage: 30 kV Mass range (m / z): 0~1500 Measurement range: 100μm×100μm Number of scans: 16 scans / cycle Number of pixels (per side): 256 pixels Etching ions: Ar gas cluster ion beam (Ar-GCIB) Etching ion accelerating voltage: 5.0 kV

[0151] Example 2 Biaxially stretched polyethylene terephthalate film (thickness 25 μm, surface orientation degree: Y max / Y min and arithmetic mean roughness Ra), a lubricant (erucic acid amide (coating amount 6 mg / m 2 ) and polyether-modified silicone oil (application amount 1 mg / m 2 )) was applied (total application amount was 7 mg / m 2 ) A battery packaging material was obtained in the same manner as in Example 1.

[0152] Example 3 As the base layer, a biaxially oriented polyethylene terephthalate film (thickness 12 μm, surface orientation degree: Y in Table 1) was used. max / Y minA laminated film was prepared by dry laminating a biaxially oriented nylon film (15 μm thick) and a biaxially oriented polyethylene terephthalate film (having a surface roughness of 100 μm and an arithmetic mean roughness Ra). In this laminated film, the biaxially oriented polyethylene terephthalate film and the biaxially oriented nylon film were bonded together with a urethane adhesive (3 μm thick after curing) using a polyol and an isocyanate curing agent. Next, a barrier layer composed of aluminum foil (JIS H4160:1994 A8021H-O, thickness 40 μm) that had been chemically treated on both sides to provide an acid-resistant coating was laminated on the biaxially oriented nylon film side by dry laminating. Specifically, a two-component polyurethane adhesive (polyol compound and aromatic isocyanate compound) was applied to one side of the aluminum foil with the acid-resistant coating, forming an adhesive layer (3 μm thick) on the aluminum foil. Next, the adhesive layer on the aluminum foil was laminated to the biaxially oriented nylon film side of the substrate layer, and then aging treatment was performed to produce a laminate of substrate layer (biaxially oriented polyethylene terephthalate film / adhesive / biaxially oriented nylon film) / adhesive layer / barrier layer with acid-resistant coatings on both sides. The aluminum foil used as the barrier layer had acid-resistant coatings containing chromium oxide and phosphate on both sides. Analysis of the acid-resistant coating on the barrier layer was performed using time-of-flight secondary ion mass spectrometry, as in Example 1. As a result, CrPO2 + , CrPO4 - Secondary ions consisting of Cr, P, and O were detected.

[0153] Next, maleic anhydride-modified polypropylene (40 μm thick) as an adhesive layer and random polypropylene (40 μm thick) as a heat-sealable resin layer were co-extruded onto the barrier layer of the obtained laminate, thereby laminating an adhesive layer / heat-sealable resin layer on the barrier layer. Next, the obtained laminate was aged and heated to obtain a battery packaging material in which a base layer / adhesive layer / barrier layer / adhesive layer / heat-sealable resin layer were laminated in this order.

[0154] (Comparative Example 1) The biaxially stretched polyethylene terephthalate film of the base layer has a surface orientation degree of Y as shown in Table 1. max / Y min A battery packaging material was obtained in the same manner as in Example 3, except that a surface having a roughness of 0.01 mm and an arithmetic mean roughness Ra was used.

[0155] (Comparative Example 2) A polyethylene terephthalate film and a nylon film were laminated by coextrusion to prepare a biaxially stretched laminated film. The biaxially stretched polyethylene terephthalate film (thickness 5 μm, surface orientation degree: Y in Table 1) of the laminated film constituting the base layer was max / Y min and arithmetic mean roughness Ra) and a biaxially oriented nylon film (thickness 20 μm), an adhesive layer (thickness 1 μm) made of polyester (polyester-based elastomer) is present. The laminated film is composed of a biaxially oriented polyethylene terephthalate film, adhesive, and biaxially oriented nylon film laminated in this order. Next, both surfaces of the biaxially oriented nylon film were subjected to a chemical conversion treatment, and a barrier layer made of aluminum foil (JIS H4160:1994 A8021H-O, thickness 40 μm) with an acid-resistant coating was laminated by dry lamination. Specifically, a two-component polyurethane adhesive (polyol compound and aromatic isocyanate compound) was applied to one side of the aluminum foil with the acid-resistant coating to form an adhesive layer (thickness 3 μm). Next, the adhesive layer on the barrier layer with the acid-resistant coating was laminated to the biaxially oriented nylon film side of the base layer, and then an aging treatment was performed to produce a laminate of base layer (biaxially oriented polyethylene terephthalate film / adhesive / biaxially oriented nylon film) / adhesive layer / barrier layer with acid-resistant coatings on both sides.

[0156] Next, an adhesive (2 μm thick after curing) consisting of a carboxyl-containing amorphous polyolefin resin and a polyfunctional isocyanate compound was applied and dried at 100°C. The barrier layer side of the resulting laminate was bonded to a non-oriented polypropylene film (CPP, 80 μm thick) by passing it between two rolls set at 60°C, thereby laminating an adhesive layer / heat-sealable resin layer on the barrier layer. Next, an aging treatment was performed to obtain a battery packaging material in which the substrate layer (biaxially oriented polyethylene terephthalate film / adhesive / biaxially oriented nylon film) / adhesive layer / barrier layer / adhesive layer / non-oriented polypropylene film was laminated in this order.

[0157] (Comparative Example 3) The biaxially stretched polyethylene terephthalate film of the base layer has a surface orientation degree of Y as shown in Table 1. max / Y min A battery packaging material was obtained in the same manner as in Example 3, except that a surface having a roughness of 0.01 mm and an arithmetic mean roughness Ra was used.

[0158] Comparative Example 4 The biaxially stretched polyethylene terephthalate film of the base layer has a surface orientation degree of Y as shown in Table 1. max / Y min A battery packaging material was obtained in the same manner as in Example 3, except that a surface having a roughness of 0.01 mm and an arithmetic mean roughness Ra was used.

[0159] (Comparative Example 5) The biaxially stretched polyethylene terephthalate film of the base layer has a surface orientation degree of Y as shown in Table 1. max / Y min A battery packaging material was obtained in the same manner as in Example 3, except that a surface having a roughness of 0.01 mm and an arithmetic mean roughness Ra was used.

[0160] (Comparative Example 6) Biaxially stretched polyethylene terephthalate film (thickness 25 μm, surface orientation degree: Y max / Y min and arithmetic mean roughness Ra) was coated with a lubricant (erucic acid amide) (coating amount 7 mg / m 2) A battery packaging material was obtained in the same manner as in Comparative Example 2.

[0161] (Comparative Example 7) Biaxially stretched polyethylene terephthalate film (thickness 25 μm, surface orientation degree: Y max / Y min and arithmetic mean roughness Ra), a lubricant (erucic acid amide) was applied (application amount 10 mg / m 2 ) A battery packaging material was obtained in the same manner as in Comparative Example 2.

[0162] <Measurement of surface orientation> For the biaxially stretched polyethylene terephthalate film surface (the surface opposite the barrier layer) of each battery packaging material prepared above, infrared absorption spectra were obtained in 18 directions at 10° intervals from 0° to 170° using Fourier transform infrared spectroscopy (FT-IR) attenuated total reflection (ATR). The wavenumber of the infrared absorption spectrum for each of the 18 directions was 1340 cm. -1 Absorption peak intensity Y at 1340 (CH2 vertical vibration) and wave number 1410 cm -1 Absorption peak intensity Y at 1410 (C=C stretching vibration) 1340 / Y 1410 Calculate the maximum value Y max and the minimum value Y min From the above, the surface orientation degree: Y max / Y min The specific conditions for measuring the infrared absorption spectrum are as follows. The results are shown in Table 1.

[0163] In Example 2 and Comparative Examples 6 and 7, the lubricant on the surface of the biaxially stretched polyethylene terephthalate film was wiped off with 2-butanone, and the degree of surface orientation was measured on the surface of the biaxially stretched polyethylene terephthalate film.

[0164] (Infrared absorption spectrum measurement conditions) Spectrometer: Nicolet iS10 FT-IR manufactured by Thermo Fisher Scientific Attachment: Single reflection ATR attachment (Seagull) Detector: MCT (Hg Cd Te) Wavenumber resolution: 8cm -1 Number of times accumulated: 128 IRE:Ge Incident angle: 30° Polarizer: Wire grid, S polarization Baseline: Wavenumber 1800-2000cm -1 Average intensity in the range Wave number 1340cm -1 Absorption peak intensity Y at 1340 : Wave number 1335~1342cm -1 The maximum peak intensity in the range minus the baseline value Wave number 1410cm -1 Absorption peak intensity Y at 1410 : Wave number 1400~1410cm -1 The maximum peak intensity in the range minus the baseline value

[0165] To obtain infrared absorption spectra in 18 directions, the sample with the exposed polyester film was placed horizontally on a sample holder and rotated by 10° with the Ge crystal placed on top of the sample. The angle of incidence is the angle between the perpendicular (normal) line and the incident light.

[0166] <Measurement of arithmetic mean roughness Ra of polyethylene terephthalate film surface> The arithmetic mean roughness Ra of the biaxially oriented polyethylene terephthalate film (polyester film layer) constituting the outermost surface of each battery packaging material obtained above was measured in accordance with the method specified in JIS B 0601-2001. The arithmetic mean roughness Ra was measured using a Zygo NewView 7300 white light interferometer with a measurement area of ​​0.22 mm square (50x objective lens, 1x zoom lens) and tilt correction (cylinder). The arithmetic mean roughness Ra was measured in the battery packaging material state. Note that the surface of the polyethylene terephthalate film was not wiped during the measurement. The results are shown in Table 1.

[0167] <Evaluation of printability of polyethylene terephthalate film surface> Ink was applied to the biaxially oriented polyethylene terephthalate film surface of each battery packaging material prepared above using an inkjet printer (Markem-Image 9040 (1.1M head)) at a temperature of 24°C and a relative humidity of 50%. The ink was then allowed to dry for 10 seconds. The printability of the biaxially oriented polyethylene terephthalate film surface was then evaluated based on the radius and circularity of the dots in the printed area. The printing conditions were ink viscosity: 3.4 cps, temperature: 34°C, pressure: 270 bar, nozzle size: 50 μm diameter, and resolution (dot density): 115 dpi. The method for measuring the radius and circularity of the printed dots is described below. The evaluation was performed on the battery packaging material. The radius and circularity of the printed dots were the average values ​​of three samples. Note that the surface of the polyethylene terephthalate film was not wiped during the evaluation. The results are shown in Table 1.

[0168] The distance between the print head of the inkjet printer and the surface of the biaxially stretched polyethylene terephthalate film was set to 20 mm, and 5157E standard ink was used.

[0169] The radius and circularity of the dots in the printed portions formed on the surface of the biaxially stretched polyethylene terephthalate film were observed using a laser microscope (Keyence Laser Microscope VK-9710) at a magnification of 10. For reference, images of the printed portions formed on the surface of the biaxially stretched polyethylene terephthalate film observed with the laser microscope for Example 2 and Comparative Example 7 are shown in Figure 4 (Example 2) and Figure 5 (Comparative Example 7), respectively.

[0170] (Method for measuring the radius of printed dots) The shape of the dots in the printed area dropped onto the surface of each biaxially stretched polyethylene terephthalate film was analyzed using the laser microscope image, and the radius of the circle passing through the three points (= the radius of the dots in the printed area) was determined using KEYENCE's VK Analyzer Ver. 2.4.0.0 analysis software. The results are shown in Table 1.

[0171] (Evaluation of the circularity of printed dots) The circularity of dots in the printed area formed by ink droplets on the surface of each biaxially stretched polyethylene terephthalate film was measured using image analysis software WinROOF (Version 6.6.0) manufactured by Mitani Shoji. The analysis was performed on a figure connecting the center points of the boundary pixels that make up the outline of the dot. On the analysis screen of WinRoof, this value is displayed as circularity II. The circularity of dots in the printed area is calculated using the following formula. The circularity of dots in the printed area was evaluated according to the following criteria. The results are shown in Table 1. For reference, the measured circularity of dots in the printed area for Example 2 (Figure 4) and Comparative Example 7 (Figure 5) are shown in Table 1. Circularity of printed dots = 4π x (area of ​​dots) / (perimeter of dots) 2 A: The circularity of the dots in the printed area is 0.725 or more, and the dots in the printed area have a beautiful circular shape on the surface of the biaxially oriented polyethylene terephthalate film. B: The circularity of the dots in the printed area is 0.700 or more and less than 0.725, and the dots in the printed area have an irregular circular shape on the surface of the biaxially stretched polyethylene terephthalate film.

[0172] [Table 1]

[0173] In the battery packaging materials of Examples 1 to 3, the polyester film layer constituting the outermost surface is a polymer having the formula: Y max / Y min <1.4), the radius of the dots in the printed area was small, and the circularity of the dots in the printed area was also evaluated to be excellent, demonstrating excellent printability. The results of Examples 1 to 3 show that excellent printability is exhibited regardless of whether a lubricant is present on the surface of the polyester layer. In contrast, the battery packaging materials of Comparative Examples 1 to 7 have a polyester film layer constituting the outermost surface that is a compound represented by the formula: Y max / Y min The relationship of <1.4 was not satisfied, and either the radius of the dots in the printed area was large or the circularity of the dots in the printed area was poor. For example, in Comparative Example 7, although the radius of the dots in the printed area was small, the circularity was low at 0.723, and the dots in the printed area had an irregular circular shape on the surface of the polyethylene terephthalate film layer, resulting in poor printability (see Figure 5). In Comparative Example 6, a lubricant was present on the surface of the polyester layer, and although the radius of the dots in the printed area was similar to that of Comparative Example 2, the radius of the dots in the printed area was larger than in Examples 1 to 3, resulting in poor printability. Furthermore, in Comparative Example 7, in which the amount of lubricant was increased compared to Comparative Example 6, the radius of the dots in the printed area was small as described above, but the dots in the printed area had an irregular circular shape, resulting in poor printability. [Explanation of symbols]

[0174] 1 Base material layer 2 Adhesive layer 3 Barrier layer 4 Heat-fusible resin layer 5 Adhesive layer

Claims

1. The laminate is composed of a substrate layer located on the outermost surface, a barrier layer, and a heat-sealable resin layer, in this order; the outermost surface of the base material layer is constituted by a polyester film layer, the polyester film layer is composed of a biaxially oriented polyethylene terephthalate film, A battery packaging material that satisfies the following formula when infrared absorption spectra are obtained for the surface of the polyester film layer in 18 directions at 10° increments from 0° to 170° using the total reflection method of Fourier transform infrared spectroscopy. Y max / Y min <1.4 Y max In each of the 18 directions, the infrared absorption spectrum wave number is 1340 cm -1 Absorption peak intensity Y 1340 , wave number 1410 cm -1 Absorption peak intensity Y 1410 It is the maximum value among the values ​​divided by . Y min In each of the 18 directions, the infrared absorption spectrum wave number is 1340 cm -1 Absorption peak intensity Y 1340 , wave number 1410 cm -1 Absorption peak intensity Y 1410 It is the smallest value among the values ​​divided by

2. The battery packaging material according to claim 1 , which is used in an application in which printing is performed on the surface of the polyester film layer.

3. 3. The battery packaging material according to claim 1, wherein the arithmetic mean roughness Ra of the surface of the polyester film layer measured in accordance with the method specified in JIS B 0601-2001 is 10 nm or more.

4. an adhesive layer is provided between the barrier layer and the heat-sealable resin layer, The battery packaging material according to any one of claims 1 to 3, wherein the adhesive layer contains an acid-modified polyolefin.

5. the acid-modified polyolefin of the adhesive layer is maleic anhydride-modified polypropylene, The battery packaging material according to claim 4 , wherein the heat-sealable resin layer contains polypropylene.

6. The thickness of the adhesive layer is 50 μm or less, The thickness of the adhesive layer is 20 μm or less, or The battery packaging material according to claim 4 or 5, wherein the adhesive layer has a thickness of more than 20 μm and not more than 50 μm.

7. The battery packaging material according to any one of claims 4 to 6, which is a co-extruded laminate of the adhesive layer and the heat-sealable resin layer.

8. an acid-resistant coating is provided on at least one surface of the barrier layer; When the acid-resistant coating was analyzed using time-of-flight secondary ion mass spectrometry, it was found that Ce 2 P.O. 4+ , CePO 4- , CrPO 2+ , and CrPO 4- The battery packaging material according to any one of claims 1 to 7, wherein a peak derived from at least one selected from the group consisting of:

9. 9. The battery packaging material according to claim 1, wherein at least one surface of the barrier layer is provided with an acid-resistant coating containing at least one compound selected from the group consisting of phosphorus compounds, chromium compounds, fluorides, and triazine thiol compounds.

10. The battery packaging material according to any one of claims 1 to 9, wherein at least one surface of the barrier layer is provided with an acid-resistant coating containing a cerium compound.

11. The battery packaging material according to any one of claims 1 to 10, wherein a lubricant is present in at least one of the interior and surface of the polyester film layer.

12. The thickness of the laminate is 180 μm or less, The thickness of the laminate is 160 μm or less, or The battery packaging material according to any one of claims 1 to 11, wherein the thickness of the laminate is more than 160 µm and not more than 180 µm.

13. The battery packaging material according to any one of claims 1 to 12, wherein two or more types of lubricants are present on at least one of the surface and the interior of the base material layer.

14. The battery packaging material according to any one of claims 1 to 13, wherein at least two selected from the group consisting of saturated fatty acid amides, unsaturated fatty acid amides, substituted amides, methylol amides, saturated fatty acid bisamides, unsaturated fatty acid bisamides, fatty acid ester amides, and aromatic bisamides are present on at least one of the surface and the interior of the base material layer.

15. The thickness of the polyester film layer is 50 μm or less, The thickness of the polyester film layer is less than 10 μm, Alternatively, the battery packaging material according to any one of claims 1 to 14, wherein the polyester film layer has a thickness of 10 µm or more and 50 µm or less.

16. The battery packaging material according to any one of claims 1 to 15, wherein the barrier layer contains at least one of an aluminum alloy foil and a stainless steel foil.

17. The thickness of the barrier layer is 85 μm or less, The thickness of the barrier layer is 45 μm or less, or The battery packaging material according to any one of claims 1 to 16, wherein the barrier layer has a thickness of more than 45 µm and not more than 85 µm.

18. The battery packaging material according to any one of claims 1 to 17, wherein the heat-sealable resin layer is made of a resin containing a polyolefin skeleton.

19. The battery packaging material according to any one of claims 1 to 18, wherein the heat-sealable resin layer contains at least one selected from the group consisting of polyolefins, cyclic polyolefins, acid-modified polyolefins, and acid-modified cyclic polyolefins.

20. The battery packaging material according to any one of claims 1 to 19, wherein the heat-sealable resin layer is formed from a blend polymer in which two or more types of resins are combined.

21. The battery packaging material according to any one of claims 1 to 20, wherein the heat-sealable resin layer is formed of two or more layers of the same or different resins.

22. The battery packaging material according to any one of claims 1 to 21, wherein two or more types of lubricants are present on at least one of the surface and the interior of the heat-sealable resin layer.

23. The battery packaging material according to any one of claims 1 to 22, wherein at least two selected from the group consisting of saturated fatty acid amides, unsaturated fatty acid amides, substituted amides, methylol amides, saturated fatty acid bisamides, unsaturated fatty acid bisamides, fatty acid ester amides, and aromatic bisamides are present on at least one of the surface and the interior of the heat-sealable resin layer.

24. The method includes a step of laminating at least a substrate layer located on the outermost surface, a barrier layer, and a heat-sealable resin layer in this order to obtain a laminate, the outermost surface of the base material layer is constituted by a polyester film layer, the polyester film layer is composed of a biaxially oriented polyethylene terephthalate film, A method for producing a battery packaging material, wherein when infrared absorption spectra are obtained for the surface of the polyester film layer in 18 directions at 10° increments from 0° to 170° using the total reflection method of Fourier transform infrared spectroscopy, the following formula is satisfied: Y max / Y min <1.4 Y max In each of the 18 directions, the infrared absorption spectrum wave number is 1340 cm -1 Absorption peak intensity Y 1340 , wave number 1410 cm -1 Absorption peak intensity Y 1410 It is the maximum value among the values ​​divided by . Y min In each of the 18 directions, the infrared absorption spectrum wave number is 1340 cm -1 Absorption peak intensity Y 1340 , wave number 1410 cm -1 Absorption peak intensity Y 1410 It is the smallest value among the values ​​divided by

25. an adhesive layer is provided between the barrier layer and the heat-sealable resin layer, 25. The method for producing a battery packaging material according to claim 24, wherein the adhesive layer and the heat-sealable resin layer are formed by a co-extrusion lamination method, a thermal lamination method, a sandwich lamination method, or a method of laminating an adhesive for forming the adhesive layer on the barrier layer, and laminating the heat-sealable resin layer, which has been formed in advance into a sheet shape, on the adhesive layer.

26. an adhesive layer is provided between the barrier layer and the heat-sealable resin layer, The method for producing a battery packaging material according to claim 24 or 25, wherein the heat-sealable resin layer is formed of two or more layers of the same or different resins.

27. A battery, comprising a battery element including at least a positive electrode, a negative electrode, and an electrolyte, housed in a package formed from the battery packaging material according to any one of claims 1 to 23.

28. The battery according to claim 27 , wherein the polyester film layer has a printed portion on its surface.

29. a housing step of housing a battery element including at least a positive electrode, a negative electrode, and an electrolyte in a package made of the battery packaging material according to any one of claims 1 to 23; a step of printing on the surface of the polyester film layer at least either before or after the storing step; A method for manufacturing a battery comprising:

30. A polyester film for use in a polyester film layer located on the outermost surface of a battery packaging material, the polyester film layer is composed of a biaxially oriented polyethylene terephthalate film, A polyester film, wherein when infrared absorption spectra are obtained for the surface of the polyester film in 18 directions at 10° increments from 0° to 170° using the total reflection method of Fourier transform infrared spectroscopy, the polyester film satisfies the following formula: Y max / Y min <1.4 Y max In each of the 18 directions, the infrared absorption spectrum wave number is 1340 cm -1 Absorption peak intensity Y 1340 , wave number 1410 cm -1 Absorption peak intensity Y 1410 It is the maximum value among the values ​​divided by . Y min In each of the 18 directions, the infrared absorption spectrum wave number is 1340 cm -1 Absorption peak intensity Y 1340 , wave number 1410 cm -1 Absorption peak intensity Y 1410 It is the smallest value among the values ​​divided by

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