JP2020013796A - Battery packaging material, battery, method for producing them, and polyester film - Google Patents

Abstract

To provide a battery packaging material having a polyester film layer on the outermost surface thereof and having excellent printability of a surface of the polyester film layer.SOLUTION: The battery packaging material is configured by a laminate having at least a base material layer 1 located in the uppermost surface, a barrier layer 3, and a heat-fusible resin layer 4 in this order. The outermost surface of the base material layer is composed of a polyester film layer. When infrared absorption spectra in 18 directions are acquired from 0° to 170° in steps of 10°with respect to a surface of the polyester film layer using a total reflection method of Fourier transform infrared spectroscopy, the following formula is satisfied. Y/Y<1.4.SELECTED DRAWING: Figure 1

Description

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

  Conventionally, various types of batteries have been developed, but in all batteries, a packaging material is an indispensable member for sealing battery elements such as electrodes and electrolytes. Conventionally, metal packaging materials have been frequently used as battery packaging.

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

  Therefore, in recent years, as a battery packaging material which can be easily processed into various shapes and can be made thinner and lighter, a film-like laminate in which a base material / barrier layer / heat-fusible resin layer is sequentially laminated. (For example, see Patent Document 1). In such a battery packaging material, generally, a concave portion is formed by cold molding, and a battery element such as an electrode or an electrolytic solution is disposed in a space formed by the concave portion. Is thermally fused to obtain a battery in which a battery element is accommodated inside a battery packaging material.

  In various packaging materials composed of the above laminates, ink is printed on the surface of the base material layer to form barcodes, patterns, characters, etc., and is adhered on the base material layer on the printed side. A method of printing on a packaging material by a method of laminating an agent and a barrier layer (generally called back printing) has been widely adopted. However, if such a printed surface exists between the base material layer and the barrier layer, the adhesion between the base material layer and the barrier layer is reduced, and delamination is likely to occur between the layers. In particular, since a battery to which a battery packaging material is applied requires high safety, such a method of printing by back printing is avoided in a battery packaging material. Therefore, conventionally, when a print such as a barcode is formed on a battery packaging material, a method in which a seal formed with the print is attached to the surface of the base material layer is generally adopted.

JP 2008-287971 A

  However, when the seal on which the print is formed is attached to the surface of the base material layer, the thickness and weight of the battery packaging material increase. Therefore, the present inventors have considered a method of printing by ink printing directly on the surface of the base material layer of the battery packaging material in view of the recent trend of further thinning and lightening of the battery packaging material. investigated.

  As a method of printing by printing ink directly on the surface of the base material layer of the battery packaging material, for example, pad printing (also called tampo printing) or inkjet printing is known. Pad printing is the following printing method. First, ink is poured into a concave portion of a flat plate on which a pattern to be printed is etched. Next, a silicon pad is pressed from above the concave portion to transfer the ink to the silicon pad. Next, the ink transferred to the surface of the silicon pad is transferred to a printing target to form a print on the printing target. In such pad printing, the ink is transferred to the printing object using an elastic silicon pad or the like, so that it is easy to print on the surface of the molded battery packaging material, and the battery element is formed of the battery packaging material. After sealing, there is an advantage that printing can be performed on the battery. In addition, similar advantages are obtained in ink jet printing.

  However, the inventors of the present invention have studied that, in a battery packaging material having a polyester film layer on the outermost surface, when printing ink on the surface of the polyester film layer, the ink spread on the surface of the polyester film layer is inappropriate. Or the dots of the printing portion formed by the ink are likely to have an irregular shape, and it is difficult to form a print of a desired size and shape.

  Under such circumstances, the present invention has as its main object to provide a battery packaging material having a polyester film layer on the outermost surface and having excellent printability on the surface of the polyester film layer. .

The present inventor has conducted intensive studies in order to solve the above problems. As a result, at least, a substrate layer located on the outermost surface, a barrier layer, and a heat-fusible resin layer are formed in this order from a laminate, and the outermost surface of the substrate layer is formed of a polyester film layer. Using the total reflection method of Fourier transform infrared spectroscopy, when the surface of the polyester film layer obtained infrared absorption spectrum in 18 directions from 0 ° to 170 ° in steps of 10 °, the following formula: The packaging material for batteries that satisfies is that the spread of the ink on the surface of the polyester film layer becomes inappropriate and the dots in the printed area are suppressed from becoming irregular, and excellent printability is exhibited. Was found.
Y _max / Y _min <1.4
Y _max is the maximum value among the values obtained by dividing the absorption peak intensity Y ₁₃₄₀ at the wave number of ₁₃₄₀ cm ⁻¹ of the infrared absorption spectrum by the absorption peak intensity Y ₁₄₁₀ at the wave number of ₁₄₁₀ cm ⁻¹ in each of the 18 directions. It is.
Y _min is the minimum value among the values obtained by dividing the absorption peak intensity Y ₁₃₄₀ at the wave number of ₁₃₄₀ cm ⁻¹ of the infrared absorption spectrum by the absorption peak intensity Y ₁₄₁₀ at the wave number of ₁₄₁₀ cm ⁻¹ in each of the 18 directions. It is.
In the calculation of the maximum value _Ymax and the minimum value _Ymin , _Y1340 / _Y1410 is obtained for each of the 18 directions, and the maximum value _Ymax and the minimum value _Ymin are selected from these.

  The present invention has been completed by further study based on these findings.

That is, the present invention provides the following aspects of the invention.
Item 1. At least, a base material layer located on the outermost surface, a barrier layer, and a heat-fusible resin layer, which is composed of a laminate including in this order,
The outermost surface of the base material layer is constituted by a polyester film layer,
When the surface of the polyester film layer is subjected to infrared absorption spectra in 18 directions from 0 ° to 170 ° in increments of 10 ° using the total reflection method of Fourier transform infrared spectroscopy, the following formula is satisfied. , Battery packaging materials.
Y _max / Y _min <1.4
Y _max is the maximum value among the values obtained by dividing the absorption peak intensity Y ₁₃₄₀ at the wave number of ₁₃₄₀ cm ⁻¹ of the infrared absorption spectrum by the absorption peak intensity Y ₁₄₁₀ at the wave number of ₁₄₁₀ cm ⁻¹ in each of the 18 directions. It is.
Y _min is the minimum value among the values obtained by dividing the absorption peak intensity Y ₁₃₄₀ at the wave number of ₁₃₄₀ cm ⁻¹ of the infrared absorption spectrum by the absorption peak intensity Y ₁₄₁₀ at the wave number of ₁₄₁₀ cm ⁻¹ in each of the 18 directions. It is.
Item 2. Item 2. The battery packaging material according to Item 1, which is used for an application in which printing is performed on a surface of the polyester film layer.
Item 3. Item 3. The battery packaging material according to item 1 or 2, wherein the arithmetic average roughness Ra measured on the surface of the polyester film layer is 10 nm or more in accordance with the method specified in JIS B0601-2001.
Item 4. An adhesive layer is provided between the barrier layer and the heat-fusible resin layer,
Item 4. The packaging material for a battery 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 a maleic anhydride-modified polypropylene,
Item 5. The packaging material for a battery according to Item 4, wherein the heat-fusible resin layer contains polypropylene.
Item 6. Item 4. The adhesive layer according to any one of Items 4 to 5, wherein the adhesive layer 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 a compound having an epoxy group. A packaging material for a battery according to any one of the above.
Item 7. Item 4. 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 C—O—C bond. 7. The packaging material for a battery according to any one of items 1 to 6.
Item 8. Item 8. The battery packaging material according to any one of Items 4 to 7, wherein the adhesive layer contains at least one selected from the group consisting of a urethane resin, an ester resin, and an epoxy resin.
Item 9. Item 10. The packaging material for a battery according to any one of Items 4 to 8, wherein the thickness of the adhesive layer is 50 µm or less.
Item 10. Item 10. The battery packaging material according to any one of Items 4 to 8, wherein the thickness of the adhesive layer is 10 μm or more and 50 μm or less.
Item 11. Item 10. The packaging material for a battery according to any one of Items 4 to 10, which is a co-extruded laminate of the adhesive layer and the heat-fusible resin layer.
Item 12. 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 m or more and 50 m or less.
Item 13. Item 13. The battery packaging material according to any one of Items 1 to 12, wherein the polyester film layer is formed of a stretched polyester film.
Item 14. When the surface of the polyester film layer is subjected to infrared absorption spectra in 18 directions from 0 ° to 170 ° in increments of 10 ° using the total reflection method of Fourier transform infrared spectroscopy, the following formula is satisfied. 14. The packaging material for a battery according to any one of items 1 to 13.
1.1 ≦ Y _max / Y _min <1.4
Item 15. At least one surface of the barrier layer has an acid-resistant film,
When the acid-resistant coating is analyzed by time-of-flight secondary ion mass spectrometry, at least one selected from the group consisting of Ce ₂ PO ⁴⁺ , CePO ^4- , CrPO ²⁺ , and CrPO ^4- Item 15. The battery packaging material according to any one of Items 1 to 14, wherein a peak derived from a species is detected.
Item 16. Item 1. Any one of Items 1 to 15, wherein at least one surface of the barrier layer is provided with an acid-resistant film containing at least one selected from the group consisting of a phosphorus compound, a chromium compound, a fluoride, and a triazine thiol compound. The packaging material for batteries according to 1.
Item 17. Item 17. The packaging material for a battery according to any one of Items 1 to 16, further comprising an acid-resistant film containing a cerium compound on at least one surface of the barrier layer.
Item 18. Item 18. The packaging material for a battery according to any one of Items 1 to 17, wherein a lubricant is present in at least one of the inside and the surface of the polyester film layer.
Item 19. A battery, wherein a battery element including at least a positive electrode, a negative electrode, and an electrolyte is housed in a package formed of the battery packaging material according to any one of Items 1 to 18.
Item 20. Item 20. The battery according to item 19, having a printed portion on a surface of the polyester film layer.
Item 21. An accommodation step of accommodating a battery element having 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,
At least one of before and after the housing step, a step of printing on the surface of the polyester film layer,
A method for producing a battery, comprising:
Item 22. A polyester film for use in a polyester film layer located on the outermost surface of the battery packaging material,
Using the total reflection method of Fourier transform infrared spectroscopy, when the surface of the polyester film obtained an infrared absorption spectrum in 18 directions from 0 ° to 170 ° in increments of 10 °, the following formula is satisfied: Polyester film.
Y _max / Y _min <1.4
Y _max is the maximum value among the values obtained by dividing the absorption peak intensity Y ₁₃₄₀ at the wave number of ₁₃₄₀ cm ⁻¹ of the infrared absorption spectrum by the absorption peak intensity Y ₁₄₁₀ at the wave number of ₁₄₁₀ cm ⁻¹ in each of the 18 directions. It is.
Y _min is the minimum value among the values obtained by dividing the absorption peak intensity Y ₁₃₄₀ at the wave number of ₁₃₄₀ cm ⁻¹ of the infrared absorption spectrum by the absorption peak intensity Y ₁₄₁₀ at the wave number of ₁₄₁₀ cm ⁻¹ in each of the 18 directions. It is.
Item 23. A polyester film that satisfies the following formula when the infrared reflection spectrum in 18 directions is obtained from 0 ° to 170 ° in steps of 10 ° using the total reflection method of Fourier transform infrared spectroscopy. As a polyester film layer located on the outermost surface of a battery packaging material.
Y _max / Y _min <1.4
Y _max is the maximum value among the values obtained by dividing the absorption peak intensity Y ₁₃₄₀ at the wave number of ₁₃₄₀ cm ⁻¹ of the infrared absorption spectrum by the absorption peak intensity Y ₁₄₁₀ at the wave number of ₁₄₁₀ cm ⁻¹ in each of the 18 directions. It is.
Y _min is the minimum value among the values obtained by dividing the absorption peak intensity Y ₁₃₄₀ at the wave number of ₁₃₄₀ cm ⁻¹ of the infrared absorption spectrum by the absorption peak intensity Y ₁₄₁₀ at the wave number of ₁₄₁₀ cm ⁻¹ in each of the 18 directions. It is.

  ADVANTAGE OF THE INVENTION According to this invention, in the battery packaging material provided with a polyester film layer on the outermost surface, the battery packaging material excellent in the printability of the surface of the said polyester film layer can be provided.

It is a figure showing an example of the section structure of the battery packaging material of the present invention. It is a figure showing an example of the section structure of the battery packaging material of the present invention. It is a figure showing an example of the section structure of the battery packaging material of the present invention. 6 is an image of a printed portion formed on the surface of a biaxially stretched polyethylene terephthalate film observed with a laser microscope in Example 2. 13 is an image of a printed portion formed on the surface of a biaxially stretched polyethylene terephthalate film observed with a laser microscope for Comparative Example 7.

Battery packaging material of the present invention, at least, a substrate layer located on the outermost surface, a barrier layer, and a laminate including a heat-fusible resin layer in this order, the outermost surface of the substrate layer, Consisting of a polyester film layer, using the total reflection method of Fourier transform infrared spectroscopy, the surface of the polyester film layer was obtained in 18 directions of infrared absorption spectrum from 0 ° to 170 ° in steps of 10 °. In this case, the following expression is satisfied. Hereinafter, the battery packaging material of the present invention will be described in detail.
Y _max / Y _min <1.4
In the above formula, Y _max, the at 18 each direction direction, respectively, the infrared absorption spectrum at a wavenumber of 1340 cm ^-1 absorption peak intensity Y ₁₃₄₀ in the (CH ₂ wagging vibrations), the absorption peak intensity at a wave number 1410 cm ^-1 This is the maximum value among the values divided by Y ₁₄₁₀ (C = C stretching vibration).
Y _min is the minimum value among the values obtained by dividing the absorption peak intensity Y ₁₃₄₀ at the wave number of ₁₃₄₀ cm ⁻¹ of the infrared absorption spectrum by the absorption peak intensity Y ₁₄₁₀ at the wave number of ₁₄₁₀ cm ⁻¹ in each of the 18 directions. It is.
In the calculation of the maximum value _Ymax and the minimum value _Ymin , _Y1340 / _Y1410 is obtained for each of the 18 directions, and the maximum value _Ymax and the minimum value _Ymin are selected from these.

  Hereinafter, the battery packaging material of the present invention will be described in detail. In the present specification, the numerical range indicated by “to” means “over” and “below”. For example, the notation of 2 to 15 mm means 2 mm or more and 15 mm or less.

1. Laminate Structure of Battery Packaging Material The battery packaging material of the present invention includes, for example, as shown in FIG. 1, a base layer 1, a barrier layer 3, and a heat-fusible resin layer 4 located on the outermost surface in this order. Consists of a laminate. The outermost surface of the base material layer 1 is constituted by a polyester film layer. In the battery packaging material of the present invention, the polyester film layer is on the outermost layer side, and the heat-fusible resin layer 4 is on the innermost layer. That is, when assembling the battery, the heat-fusible resin layers 4 located on the periphery of the battery element are heat-sealed to seal the battery element, thereby sealing the battery element.

  As described later, the base material layer 1 may include another layer in addition to the polyester film layer. When the base material layer 1 includes the other layer, the polyester film layer and the other layer may be bonded by an adhesive layer. In addition, for example, as shown in FIG. 2, the battery packaging material of the present invention may further include an adhesive layer 2 between a base layer 1 and a barrier layer 3 for the purpose of enhancing the adhesiveness between them. You may have. Further, an adhesive layer 5 may be provided between the barrier layer 3 and the heat-fusible resin layer 4 as needed for the purpose of enhancing the adhesiveness between them.

  The total thickness of the laminate constituting the battery packaging material of the present invention is not particularly limited, but is preferably about 180 μm or less from the viewpoint of improving the moldability while reducing the total thickness of the laminate as much as possible. More preferably, it is about 35 to 160 μm, and further preferably, about 45 to 150 μm.

  The battery packaging material of the present invention can be suitably used for applications in which printing is performed on the surface of the polyester film layer located on the outermost surface. As the printing with the ink, for example, the above-described pad printing, ink jet printing, and the like are preferable, and particularly, ink jet printing is preferable. As the solvent contained in the ink, preferably, methyl ethyl ketone, acetone, isopropyl alcohol, ethanol and the like are used. The solvent may be used alone or in combination of two or more.

2. Each layer forming the battery packaging material [base layer 1]
In the battery packaging material of the present invention, the base material layer 1 is a layer located on the outermost surface. The outermost surface of the base material layer 1 is constituted by 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 adheres constitutes the outermost surface of the battery packaging material. For this reason, also with respect to the base material layer 1 on which the lubricant is present on the surface, the base material layer 1 is a layer located on the outermost surface of the battery packaging material.

In the battery packaging material of the present invention, the polyester film layer constituting the outermost surface uses a total reflection method of Fourier transform infrared spectroscopy, and the surface of the polyester film layer is 10 ° from 0 ° to 170 °. When the infrared absorption spectrum in 18 directions is acquired at every step, the following expression is satisfied.
Y _max / Y _min <1.4
Y _max is the maximum value among the values obtained by dividing the absorption peak intensity Y ₁₃₄₀ at the wave number of ₁₃₄₀ cm ⁻¹ of the infrared absorption spectrum by the absorption peak intensity Y ₁₄₁₀ at the wave number of ₁₄₁₀ cm ⁻¹ in each of the 18 directions. It is.
Further, Y _min is a value obtained by dividing the absorption peak intensity Y ₁₃₄₀ at a wave number of ₁₃₄₀ cm ⁻¹ of the infrared absorption spectrum by the absorption peak intensity Y ₁₄₁₀ at a wave number of ₁₄₁₀ cm ⁻¹ in each of the 18 directions. This is the minimum value.
In the calculation of the maximum value _Ymax and the minimum value _Ymin , _Y1340 / _Y1410 is obtained for each of the 18 directions, and the maximum value _Ymax and the minimum value _Ymin are selected from these.

  In the battery packaging material of the present invention, the outermost surface of the base material layer is constituted by a polyester film layer, and the polyester film layer has the specific surface orientation degree, so that the outermost surface is Despite being constituted by a polyester film, excellent printability is exhibited. This mechanism can be considered, for example, as follows. That is, in the battery packaging material of the present invention, since the polyester film layer constituting the outermost surface has the specific surface orientation degree, it can be said that the orientation degree of polyester molecules in the polyester film layer is low. . Therefore, it is considered that the ink easily spreads in a uniform direction on the surface of the polyester film layer, and excellent printability is exhibited. In a conventional battery packaging material, when a polyester film layer is used as a base material layer, a material having a high degree of orientation of polyester molecules, such as greatly stretching a polyester film, has been used from the viewpoint of enhancing moldability. However, in the present invention, the polyester film layer constituting the outermost surface has the above-mentioned degree of surface orientation, so that excellent printability is exhibited. The presence of a lubricant on the surface of the base material layer, or by performing a surface treatment on the base material layer, there is a method for improving the printability, these methods can be adopted in the present invention, but in the present invention, Since the polyester film layer has the specific degree of surface orientation, excellent printability is exhibited even though the outermost surface is formed of the polyester film.

  Specific measurement conditions of the infrared absorption spectrum are as follows. The measurement of the infrared absorption spectrum on the surface of the polyester film layer can be performed in a state of being laminated on the battery packaging material.

(Measurement conditions of infrared absorption spectrum)
Spectroscope (includes a single reflection ATR accessory device)
Detector: MCT (Hg Cd Te)
Wave number resolution: 8 cm ^-1
Number of accumulation: 128 times IRE: Ge
Incident angle: 30 °
Polarizer: wire-grid, S-polarized light Baseline: absorption peak intensity at average wavenumber 1340 cm ^-1 of the intensity in the wave number range of 1800~2000cm ^-1 Y _1340: the maximum value of the peak intensity in the range of wave number 1335～1342Cm ^-1 based absorption peak intensity at a wave number 1410 cm ^-1 minus the value of the line Y _1410: minus the baseline values from the maximum value of the peak intensity in the range of wave number 1400～1410Cm ^-1

  The infrared absorption spectrum in 18 directions is obtained by placing the sample with the exposed polyester film horizontally on a sample holder and rotating the Ge crystal placed on the sample by 10 °. The incident angle is the angle between the perpendicular (normal) and the incident light.

From the viewpoint of improving the printing suitability of the battery packaging material, the upper limit of the degree of surface orientation ( _Ymax / _Ymin ) 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 still more preferably about 1.2 or more. About 1.0 to less than 1.4, about 1.0 to 1.3, about 1.1 to less than 1.4, about 1.1 to 1.3, about 1.2 to less than 1.4 , About 1.2 to 1.3. When the degree of surface orientation (Y _max / Y _min ) is about 1.1 or more, the formability can be suitably improved while improving the printing suitability of the battery packaging material.

The polyester film having the surface orientation degree as described above: Y _max / Y _min can be obtained by, for example, appropriately adjusting a stretching method, a stretching ratio, a stretching speed, a cooling temperature, a heat setting temperature, and the like in producing the polyester film. Can be manufactured.

  Further, in the battery packaging material of the present invention, the arithmetic average roughness Ra of the polyester film layer constituting the outermost surface is preferably from the viewpoint of improving the printability of the battery packaging material from the viewpoint of improving the printability. 1000 nm or less, more preferably about 500 nm or less, the lower limit is preferably about 10 nm or more, more preferably about 20 nm or more, and the preferable range is about 10 to 1000 nm or about 20 to 500 nm. .

  The arithmetic average roughness Ra of the polyester film layer constituting the outermost surface is a value obtained based on the method defined in JIS B 0601-2001 for the surface of the polyester film layer. As a specific measuring method, the method described in the examples can be adopted. The measurement of the arithmetic average roughness Ra of the polyester film layer can be performed in a state where the polyester film layer is laminated on the battery packaging material.

  The arithmetic average 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 when producing the polyester film. Further, the polyester film layer may contain additives described below (a flame retardant, an antiblocking agent, an antioxidant, a light stabilizer, a tackifier, an antistatic agent, etc.) as particles, and The arithmetic average roughness Ra may be adjusted. The average particle diameter of the particles is, for example, about 0.1 to 5 μm, and the content of the particles is, for example, about 0.01 to 0.1% by mass.

  As the polyester constituting the polyester film layer, specifically, polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polybutylene naphthalate, polyethylene isophthalate, copolymerized polyester having a main unit of ethylene terephthalate as a repeating unit, Copolymerized polyesters mainly containing butylene terephthalate as a repeating unit are exemplified. Examples of the copolymerized polyester mainly composed of ethylene terephthalate as a repeating unit include copolymer polyesters (hereinafter, referred to as polyethylene (terephthalate / isophthalate)) in which ethylene terephthalate is mainly composed of repeating units and polymerized with ethylene isophthalate. Polyethylene (terephthalate / isophthalate), polyethylene (terephthalate / adipate), polyethylene (terephthalate / sodium sulfoisophthalate), polyethylene (terephthalate / sodium isophthalate), polyethylene (terephthalate / phenyl-dicarboxylate) And polyethylene (terephthalate / decanedicarboxylate) and the like. Further, as the copolymer polyester containing butylene terephthalate as a main component of a repeating unit, specifically, a copolymer polyester (hereinafter referred to as polybutylene (terephthalate / isophthalate)) polymerizing butylene isophthalate with butylene terephthalate as a main component of a repeating unit , Polybutylene (terephthalate / adipate), polybutylene (terephthalate / sebacate), polybutylene (terephthalate / decanedicarboxylate), polybutylene naphthalate, and the like. These polyesters may be used alone or in a combination of two or more. Polyester has excellent heat resistance and electrolytic solution resistance, and has the advantage that whitening or the like is unlikely to occur due to adhesion of the electrolytic solution, and is suitably used as a material for forming the base material layer 1.

  The polyester film layer may be either a stretched polyester film or an unstretched polyester film, but from the viewpoint of suitably improving the moldability of the battery packaging material, preferably a stretched polyester film, more preferably a biaxially stretched polyester. It can be constituted by a film, more preferably a biaxially stretched polyethylene terephthalate film. In addition, as a stretching method, a sequential biaxial stretching method, an inflation method, a simultaneous biaxial stretching method, etc. are mentioned, for example.

  The thickness of the polyester film layer is not particularly limited, but from the viewpoint of improving the moldability while reducing the thickness of the battery packaging material, the upper limit is, for example, about 50 μm or less, preferably about 30 μm or less, more preferably About 25 μm or less, the lower limit is preferably about 1 μm or more, more preferably about 5 μm or more, and further about 10 μm or more, and the preferred range is about 1 to 50 μm, about 1 to 30 μm, About 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, about 10 to 25 μm.

The polyester film layer may be a single layer or a multilayer (multilayer structure). In addition, when the polyester film layer is a multilayer, at least the polyester film located on the outermost layer side (the side opposite to the barrier layer 3) satisfies the above-mentioned degree of surface orientation. The polyester film may have a degree of surface orientation: Y _max / Y _min of 1.4 or more.

  In addition to the polyester film layer, the base material layer 1 is formed on the barrier layer side of the polyester film layer in order to improve the moldability of the battery packaging material. It is also possible to laminate at least one of them (multilayer structure) to form the base material layer 1.

  Other resin films used for the base layer 1 include, for example, polyamide, polyolefin, epoxy resin, acrylic resin, fluororesin, polyurethane, silicon resin, phenol resin, polyetherimide, polyimide, and mixtures and copolymers thereof. And a resin film formed of a material or the like. A specific example of a configuration in which a polyester film and a resin film of a different material are laminated includes a multilayer structure in which a polyester film layer and a polyamide film layer are laminated.

  Specific examples of the polyamide film constituting the polyamide film layer include aliphatic polyamides such as nylon 6, nylon 66, nylon 610, nylon 12, nylon 46, and a copolymer of nylon 6 and nylon 6,6; Hexamethylenediamine-isophthalic acid-terephthalic acid copolymers such as nylon 6I, nylon 6T, nylon 6IT, and nylon 6I6T (I represents isophthalic acid and T represents terephthalic acid) containing structural units derived from an acid and / or isophthalic acid Polyamides, polyamides MXD6 (polyamides containing aromatics such as polymethaxylylene adipamide; alicyclic polyamides such as polyaminomethylcyclohexyl adipamide (PACM6); lactam components and 4,4'-diphenylmethane-diisocyanate Isocyanate A polyamide film obtained by copolymerizing a polyamide component, a polyesteramide copolymer or a polyetheresteramide copolymer, which is a copolymer of a copolymerized polyamide with a polyester or a polyalkylene ether glycol; These polyamide films may be used alone or in combination of two or more types.The polyamide film is excellent in stretchability and causes whitening due to resin cracking during molding. Generation can be prevented, and it is suitably used as a resin film used for the base material layer 1 together with the polyester film.

  When the base material layer 1 has a multilayer structure of a polyester film, and as a specific example of the case where the other resin film is provided, a laminate of a polyester film and a nylon film, a laminate of a plurality of polyester films is preferable. A laminate of a stretched polyester film and a stretched nylon film, and a laminate of a plurality of stretched polyester films are more preferred. For example, when the base material layer 1 has a two-layer structure, a structure in which a polyester film and a polyamide film are stacked, or a structure in which a polyester film and a polyester film are stacked is preferable, and a structure in which polyethylene terephthalate and nylon are stacked, or More preferably, polyethylene terephthalate and polyethylene terephthalate are laminated. Further, the polyester film is not easily discolored, for example, when the electrolytic solution adheres to the surface, and in the battery packaging material of the present invention, the polyester film layer constitutes the outermost surface, and thus has excellent electrolytic solution resistance. Configuration.

  When the base layer 1 has a multilayer structure, the lower limit of the thickness of the polyester film not located in the outermost layer or the resin film other than the polyester film is preferably about 3 μm or more, more preferably about 5 μm or more. The upper limit is preferably about 30 μm or less, preferably about 25 μm or less, and the preferred range is about 3 to 30 μm, about 3 to 25 μm, about 5 to 30 μm, or about 5 to 25 μm.

  When the base material layer 1 has a multilayer structure, the polyester film or each resin film may be bonded via an adhesive, or may be directly laminated without using an adhesive. When bonding is performed without using an adhesive, for example, a method of bonding in a hot melt state such as a co-extrusion method, a sandwich lamination method, or a thermal lamination method may be used. In the case of bonding via an adhesive, the adhesive used may be a two-part curable adhesive or a one-part curable adhesive. Furthermore, the bonding mechanism of the adhesive is not particularly limited, and may be any of a chemical reaction type, a solvent volatilization type, a heat melting type, a heat pressure type, an electron beam curing type, and an ultraviolet curing type. Specific examples of the adhesive include those similar to the adhesive exemplified for the adhesive layer 2. Further, the thickness of the adhesive can be the same as that of the adhesive layer 2.

  When the base material 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. Is mentioned. As the modified thermoplastic resin, 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 is used. The resin may be used alone, or two or more kinds may be used in combination. Examples of the unsaturated carboxylic acid derivative component include unsaturated carboxylic acids, acid anhydrides of unsaturated carboxylic acids, and esters of unsaturated carboxylic acids. As the unsaturated carboxylic acid derivative component, one type may be used alone, or two or more types may be used in combination.

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

  Examples of the styrene-based elastomer in the modified thermoplastic resin include styrene (hard segment) and a copolymer of butadiene or 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.

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

  As the unsaturated carboxylic acid in the modified thermoplastic resin, for example, acrylic acid, methacrylic acid, maleic acid, fumaric acid, itaconic acid, citraconic acid, tetrahydrophthalic acid, bicyclo [2,2,1] hept-2-ene- 5,6-dicarboxylic acid and the like. Examples of the acid anhydride of an unsaturated carboxylic acid include, for example, maleic anhydride, itaconic anhydride, citraconic anhydride, tetrahydrophthalic anhydride, bicyclo [2,2,1] hept-2-ene-5,6- And dicarboxylic anhydrides. Examples of unsaturated carboxylic acid esters include, for example, methyl acrylate, methyl methacrylate, ethyl methacrylate, butyl methacrylate, dimethyl maleate, monomethyl maleate, diethyl fumarate, dimethyl itaconate, dimethyl citrate, tetrahydrochloride Esters of unsaturated carboxylic acids such as dimethyl phthalate anhydride and dimethyl bicyclo [2,2,1] hept-2-ene-5,6-dicarboxylate.

  As the modified thermoplastic resin, about 0.2 to 100 parts by mass of the unsaturated carboxylic acid derivative component is reacted with 100 parts by mass of the base thermoplastic resin by heating in the presence of a radical initiator. Obtained by:

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

  Examples of the radical initiator used in the modification reaction include organic peroxides. Various materials can be selected as the organic peroxide depending on the temperature conditions and the reaction time, and examples thereof include alkyl peroxide, aryl peroxide, acyl peroxide, ketone peroxide, peroxyketal, peroxycarbonate, and peroxycarbonate. Oxyesters, hydroperoxides and the like can be mentioned. In the case of the melt grafting reaction using the twin screw extruder described above, alkyl peroxide, peroxyketal, and peroxyester are preferable, and di-t-butyl peroxide, 2,5-dimethyl-2,5-di-t- More preferably, butylperoxy-hexyne-3 and dicumyl peroxide are used.

  When the base material layer 1 has a multilayer structure, the thickness of the adhesive layer located between the polyester film and each resin film is preferably about 0.1 to 5 μm, more preferably about 0.5 to 3 μm. Can be Note that the adhesive layer may include the same coloring agent as the adhesive layer 2 described later.

  In the present invention, a lubricant is preferably present in at least one of the inside and the surface of the polyester film layer from the viewpoint of enhancing the moldability of the battery packaging material. That is, a lubricant may be contained in the polyester film layer, or a lubricant may be present on the surface of the battery packaging material. In addition, the lubricant present on the surface of the polyester film layer may be the one obtained by exuding the lubricant contained in the polyester film layer, or the lubricant applied to the surface of the polyester film layer.

  The lubricant is not particularly limited, but preferably includes an amide lubricant and a silicone lubricant. Specific examples of the lubricant include saturated fatty acid amide, unsaturated fatty acid amide, substituted amide, methylolamide, saturated fatty acid bisamide, unsaturated fatty acid bisamide, fatty acid ester amide, aromatic bisamide and the like. Specific examples of the saturated fatty acid amide include lauric amide, palmitic amide, stearic amide, behenic amide, and hydroxystearic amide. Specific examples of the unsaturated fatty acid amide include oleic acid amide and erucic acid amide. Specific examples of the substituted amide include N-oleyl palmitamide, N-stearyl stearamide, N-stearyl oleamide, N-oleyl stearamide, N-stearyl erucamide, and the like. Specific examples of methylolamide include methylol stearamide. Specific examples of the saturated fatty acid bisamide include methylene bisstearic acid amide, ethylenebiscapric acid amide, ethylenebislauric acid amide, ethylenebisstearic acid amide, ethylenebishydroxystearic acid amide, ethylenebisbehenic acid amide, hexamethylenebisstearin Acid amide, hexamethylenebisbehenamide, hexamethylenehydroxystearic acid amide, N, N'-distearyladipamide, N, N'-distearylsebacic amide and the like. Specific examples of unsaturated fatty acid bisamides include ethylene bisoleic acid amide, ethylene bis erucic acid amide, hexamethylene bis oleic acid amide, N, N'-dioleyl adipamide, N, N'-dioleyl sebacic amide And the like. Specific examples of the fatty acid ester amide include stearoamidoethyl stearate. Specific examples of the aromatic bisamide include m-xylylenebisstearic acid amide, m-xylylenebishydroxystearic acid amide, and N, N'-distearylisophthalic acid amide. As the silicone lubricant, non-reactive modified silicone oils such as alkyl-modified silicone oil, higher fatty acid ester-modified silicone oil, and polyether-modified silicone oil are preferable. One type of lubricant may be used alone, or two or more types may be used in combination.

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, is preferably about 3 mg / m ² or more, and more preferably 3 to 15 mg / m ^2. m ² , more preferably about 4 to 14 mg / m ² . In addition, even when a lubricant is present on the surface of the polyester film layer, the infrared absorption spectrum can be measured for the surface of the polyester film layer on which the lubricant is present.

  Further, additives such as a flame retardant, an anti-blocking agent, an antioxidant, a light stabilizer, a tackifier, and an antistatic agent may be present in at least one of the inside and the 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.

  The thickness (total thickness) of the base layer 1 is not particularly limited, but from the viewpoint of improving the moldability while reducing the thickness of the battery packaging material, the upper limit is, for example, about 50 μm or less, preferably about 40 μm or less. The lower limit is preferably about 3 μm or more, more preferably about 5 μm or more, and further about 10 μm or more. A preferable range of the thickness of the base material layer 1 is about 3 to 50 μm, About 40 μm, about 5 to 50 μm, about 5 to 40 μm, about 10 to 50 μm, about 10 to 40 μm.

[Adhesive layer 2]
In the battery packaging material of the present invention, the adhesive layer 2 is a layer provided between the base material layer 1 and the barrier layer 3 as necessary, in order to firmly adhere to each other.

  The adhesive layer 2 is formed of an adhesive capable of adhering the base layer 1 and the barrier layer 3. The adhesive used to form the adhesive layer 2 may be a two-part curable adhesive or a one-part curable adhesive. Further, the bonding mechanism of the adhesive used for forming the adhesive layer 2 is not particularly limited, and may be any of a chemical reaction type, a solvent volatilization type, a hot-melt type, and a hot-pressure type.

  Specific examples of the adhesive component that can be used for forming the adhesive layer 2 include polyesters such as polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polybutylene naphthalate, polyethylene isophthalate, and copolyester; Polyurethane adhesive; epoxy resin; phenolic resin; polyamides such as nylon 6, nylon 66, nylon 12, and copolymerized polyamide; polyolefins such as polyolefin, carboxylic acid-modified polyolefin, and metal-modified polyolefin; polyvinyl acetate; (Meth) acrylic resin; polyimide; polycarbonate; amino resin such as urea resin and melamine resin; rubber such as chloroprene rubber, nitrile rubber, styrene-butadiene rubber; Butter, and the like can be mentioned. One of these adhesive components may be used alone, or two or more thereof may be used in combination. Among these adhesive components, a polyurethane adhesive is preferable.

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

  Further, one or more resins (A) selected from the group consisting of a modified polypropylene and an acrylic resin, or one of a coupling agent (B) containing at least one of a silane coupling agent and a titanate coupling agent ( An adhesive containing a resin containing (A) or (B)) is also included.

  Further, the adhesive layer 2 may include a coloring agent. When the adhesive layer 2 contains a coloring agent, the packaging material for a battery can be colored. Known coloring agents such as pigments and dyes can be used. Further, only one type of colorant may be used, or two or more types may be mixed and used.

  For example, specific examples of inorganic pigments preferably include carbon black and titanium oxide. Specific examples of the organic pigments preferably include azo pigments, phthalocyanine pigments, and condensed polycyclic pigments. Examples of the 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; and phthalocyanine pigments include copper phthalocyanine pigments and non-soluble azo pigments. Blue pigments and green pigments are exemplified as metal phthalocyanine pigments, and dioxazine violet and quinacridone violet are exemplified as condensed polycyclic pigments. Further, as the pigment, a pearl pigment, a fluorescent pigment, or the like can be used.

  Among the colorants, for example, carbon black is preferable in order to make the appearance of the battery packaging material black.

  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 a median size measured by a laser diffraction / scattering type particle size distribution measuring device.

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

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

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

  The coloring layer can be formed, for example, by applying an ink containing a coloring agent to the surface of the base layer 1 or the surface of the barrier layer 3. Known coloring agents such as pigments and dyes can be used. Further, only one type of colorant may be used, or two or more types may be mixed and used.

  Specific examples of the coloring agent included in the coloring layer include the same coloring agents as those exemplified in the section of [Adhesive Layer 2].

[Barrier layer 3]
In the battery packaging material, the barrier layer 3 is a layer having a function of improving the strength of the battery packaging material and preventing the entry of water vapor, oxygen, light, and the like into the battery. The barrier layer 3 can be formed by 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, and the like. Preferably, there is. Specific examples of the metal forming the barrier layer 3 include aluminum, stainless steel, and titanium steel, and preferably aluminum or stainless steel. The barrier layer 3 is preferably formed of a metal foil, more preferably an aluminum alloy foil or a stainless steel foil.

  From the viewpoint of preventing generation of wrinkles and pinholes in the barrier layer 3 during the production of the battery packaging material, the barrier layer is made of, for example, annealed aluminum (JIS H4160: 1994 A8021H-O, JIS H4160). More preferably, it is formed of a soft aluminum foil such as 1994 A8079H-O, JIS H4000: 2014 A8021P-O, JIS H4000: 2014 A8079P-O).

  Examples of the stainless steel foil include an austenitic stainless steel foil and a ferrite stainless steel foil. The stainless steel foil is preferably made of austenitic stainless steel.

  Specific examples of the austenitic stainless steel constituting the stainless steel foil include SUS304, SUS301, SUS316L and the like, and among them, SUS304 is particularly preferable.

  The thickness of the barrier layer 3 is not particularly limited as long as it functions as a barrier layer for water vapor or the like, 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, more preferably 45 μm or less, as the lower limit, preferably about 10 μm or more, as the thickness range, for example, about 10 to 85 μm, preferably about 10 to 50 μm, more preferably It can be about 10 to 45 μm. When the barrier layer 3 is made 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, further more preferably about 40 μm or less, and still more preferably about 30 μm or less. Particularly preferably, the thickness is about 25 μm or less, the lower limit is about 10 μm or more, and the preferable thickness range is about 10 to 85 μm, about 10 to 50 μm, more preferably about 10 to 40 μm, and more preferably about 10 to 40 μm. About 10 to 30 μm, more preferably about 15 to 25 μm.

  Further, it is preferable that at least one surface, preferably both surfaces, of the barrier layer 3 is subjected to a chemical conversion treatment in order to stabilize adhesion, prevent dissolution or corrosion, and the like. Here, the chemical conversion treatment refers to a treatment for forming an acid-resistant film on the surface of the barrier layer. When an acid-resistant film is formed on the surface of the barrier layer 3 of the present invention, the barrier layer 3 includes an acid-resistant film. As the chemical conversion treatment, for example, chromate chromate using a chromate compound such as chromium nitrate, chromium fluoride, chromium sulfate, chromium acetate, chromium oxalate, chromium biphosphate, chromium acetylacetate, chromium chloride, potassium chromium sulfate, etc. Treatment; Phosphate chromate treatment using a phosphoric acid compound such as sodium phosphate, potassium phosphate, ammonium phosphate, polyphosphoric acid; Aminated phenol having a repeating unit represented by the following general formulas (1) to (4) Chromate treatment using a polymer may be mentioned. In the aminated phenol polymer, the repeating units represented by the following general formulas (1) to (4) may be contained alone or in any combination of two or more. Is also good.

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. R ¹ and R ² are the same or different and each represents a hydroxy group, an alkyl group, or a hydroxyalkyl group. In the general formulas (1) to (4), examples of the alkyl group represented by X, R ¹ and R ² include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, Examples thereof include a linear or branched alkyl group having 1 to 4 carbon atoms such as a tert-butyl group. Examples of the hydroxyalkyl group represented by X, R ¹ and R ² include, for example, a hydroxymethyl group, a 1-hydroxyethyl group, a 2-hydroxyethyl group, a 1-hydroxypropyl group, a 2-hydroxypropyl group, A linear or branched C1-C4 substituted one hydroxy group such as a hydroxypropyl group, a 1-hydroxybutyl group, a 2-hydroxybutyl group, a 3-hydroxybutyl group or a 4-hydroxybutyl group; And an alkyl group. In the general formulas (1) to (4), the alkyl group and the hydroxyalkyl group represented by X, R ¹ and R ² may be the same or different. In the general formulas (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 the repeating units represented by the general formulas (1) to (4) is, for example, preferably from 500 to 1,000,000, and more preferably from 1,000 to 20,000. .

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

As a specific method of providing an acid-resistant coating, for example, as one example, at least the inner layer side of an aluminum foil (barrier layer) is firstly treated with an alkali immersion method, an electrolytic cleaning method, an acid cleaning method, and an electrolytic cleaning method. A degreasing treatment is performed by a known treatment method such as an acid washing method and an acid activating method, and then a Cr (chromium) phosphate, a Ti (titanium) phosphate, a Zr (zirconium) phosphate, a phosphorus Treatment liquid (aqueous solution) mainly containing a metal phosphate such as acid Zn (zinc) salt and a mixture of these metal salts, or non-metal phosphate and a mixture of these non-metal salts as a main component Treatment solution (aqueous solution), or a treatment solution (aqueous solution) composed of a mixture of these with an aqueous synthetic resin such as an acrylic resin, a phenol resin, or a polyurethane, is roll-coated, gravure-printed, or dipped. By coating with a known coating method, it is possible to form the acid-resistant coating. For example, when treated with a Cr (chromium) phosphate-based treatment solution, CrPO ₄ (chromium phosphate), AlPO ₄ (aluminum phosphate), Al ₂ O ₃ (aluminum oxide), Al (OH) _x (water It becomes an acid-resistant film made of aluminum oxide), AlF _x (aluminum fluoride), etc., and when treated with a Zn (zinc) phosphate-based treatment solution, Zn ₂ PO ₄ .4H ₂ O (zinc phosphate hydrate) ), AlPO ₄ (aluminum phosphate), Al ₂ O ₃ (aluminum oxide), Al (OH) _x (aluminum hydroxide), AlF _x (aluminum fluoride) and the like.

  Further, as another example of a specific method of providing an acid-resistant film, for example, at least an inner layer side of an aluminum foil is first treated with an alkali immersion method, an electrolytic cleaning method, an acid cleaning method, an electrolytic acid cleaning method, and an acid-active method. An acid-resistant film can be formed by performing a degreasing treatment by a known treatment method such as a chemical treatment method, and then performing a known anodic oxidation treatment on the degreasing treatment surface.

  Further, as another example of the acid-resistant film, a film of a phosphorus compound (for example, phosphate) or a chromium compound (chromic acid) can be given. Examples of the phosphate type include zinc phosphate, iron phosphate, manganese phosphate, calcium phosphate, and chromium phosphate, and examples of the chromate type include chromium chromate.

  Further, as another example of the acid-resistant film, by forming an acid-resistant film of phosphate, chromate, fluoride, triazine thiol compound, etc., between the aluminum and the substrate layer at the time of embossing. Prevents delamination, dissolution and corrosion of aluminum surface by hydrogen fluoride generated by reaction between electrolyte and moisture, especially aluminum oxide present on aluminum surface is prevented from dissolving and corroding, and adhesion of aluminum surface It improves the wettability and prevents delamination between the base material layer and aluminum during heat sealing, and the embossing type exhibits the effect of preventing delamination between the base material layer and aluminum during press molding. Among the substances that form an acid-resistant film, an aqueous solution composed of a phenol resin, a chromium fluoride (3) compound, and phosphoric acid is applied to the aluminum surface, and drying and baking are favorable.

  Further, the acid-resistant film includes a layer having cerium oxide, phosphoric acid or phosphate, an anionic polymer, and a crosslinking agent for crosslinking the anionic polymer, wherein the phosphoric acid or phosphate is You may mix | blend 1-100 mass parts with respect to 100 mass parts of cerium oxides. It is preferable that the acid-resistant film has a multilayer structure further including a layer having a cationic polymer and a crosslinking agent for crosslinking the cationic polymer.

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

  Further, the phosphoric acid or phosphate is preferably condensed phosphoric acid or condensed phosphate.

  The chemical conversion treatment may be performed by only one type of chemical conversion process, or may be performed by combining two or more types of chemical conversion processes. Furthermore, these chemical conversion treatments may be performed using one kind of compound alone, or may be performed using two or more kinds of compounds in combination. Among the chemical conversion treatments, a chromate treatment, a chromate treatment using a combination of a chromate compound, a phosphoric acid compound, and an aminated phenol polymer are preferable.

  Specific examples of the acid-resistant film include those containing at least one of a phosphorus compound (such as a phosphate), a chromium compound (a chromate), a fluoride, and a triazinethiol compound. Further, an acid resistant film containing a cerium compound is also preferable. As the cerium compound, cerium oxide is preferable.

  Specific examples of the acid-resistant coating include a phosphate coating, a chromate coating, a fluoride coating, and a triazine thiol compound coating. As the acid-resistant film, one of these may be used, or a combination of a plurality of types may be used. Furthermore, as the acid-resistant coating, after the chemical conversion treatment surface of the barrier layer is degreased, a treatment solution consisting of a mixture of a metal phosphate and an aqueous synthetic resin, or a mixture of a non-metal phosphate and an aqueous synthetic resin is used. It may be formed of a processing liquid.

The analysis of the composition of the acid-resistant coating can be performed, for example, using a time-of-flight secondary ion mass spectrometry. Analysis of the composition of the acid-resistant coating using time-of-flight secondary ion mass spectrometry reveals that, for example, at least one kind of secondary ions composed of Ce, P, and O (for example, Ce ₂ PO ₄ ⁺ , CePO ₄ ^{−, and the} like) ) and, for example, secondary ion of Cr and P and O (e.g., CrPO ₂ ^+, CrPO ₄ ^- peak derived from at least one), such as is detected.

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 performing the above-mentioned chromate treatment, the chromic acid compound per 1 m ² of the surface of the barrier layer 3 About 0.5 to 50 mg, preferably about 1.0 to 40 mg in terms of chromium, about 0.5 to 50 mg, preferably about 1.0 to 40 mg of a phosphorus compound in terms of phosphorus, and 1. It is desirable that it be contained at a ratio of about 0 to 200 mg, preferably about 5.0 to 150 mg.

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

  In the chemical conversion treatment, after a solution containing a compound used for forming an acid-resistant film is applied to the surface of the barrier layer by a bar coating method, a roll coating method, a gravure coating method, an immersion method, or the like, the temperature of the barrier layer is reduced to 70%. It is performed by heating to ~ 200 ° C. Before the chemical conversion treatment is performed on the barrier layer, the barrier layer may be subjected to a degreasing treatment by an alkali immersion method, an electrolytic cleaning method, an acid cleaning method, an electrolytic acid cleaning method, or the like in advance. By performing the degreasing treatment in this manner, it is possible to more efficiently perform the chemical conversion treatment on the surface of the barrier layer.

[Heat-fusible resin layer 4]
In the battery packaging material of the present invention, the heat-fusible resin layer 4 corresponds to the innermost layer, and is a layer for sealing the battery element by heat-sealing the heat-fusible resin layers to each other at the time of assembling the battery.

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

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

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

  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 the modification include maleic acid, acrylic acid, itaconic acid, crotonic acid, maleic anhydride, and itaconic anhydride.

  The carboxylic acid-modified cyclic polyolefin is obtained by copolymerizing a part of the monomer constituting the cyclic polyolefin with α, β-unsaturated carboxylic acid or an anhydride thereof, or α, β with respect to the cyclic polyolefin. -A polymer obtained by block polymerization or graft polymerization of an 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.

  Among these resin components, preferred are carboxylic acid-modified polyolefins; more preferred are carboxylic acid-modified polypropylene.

  The heat-fusible resin layer 4 may be formed of one type of resin component alone, or may be formed of a blend polymer in which two or more types of resin components are combined. Further, the heat-fusible 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.

The heat-fusible resin layer 4 may contain a lubricant. In addition, the lubricant present on the surface of the heat-fusible resin layer 4 may be formed by exuding the lubricant contained in the resin constituting the heat-fusible resin layer 4, or may be formed by leaching the heat-fusible resin layer. The surface of No. 4 may be coated with a lubricant. When the heat-fusible resin layer 4 contains a lubricant, the moldability of the battery packaging material can be improved. The lubricant is not particularly limited, and a known lubricant can be used, and examples thereof include those exemplified for the above-described base material layer 1. A lubricant may be used alone or in combination of two or more. The amount of the lubricant present on the surface of the heat-fusible resin layer 4 is not particularly limited, and is preferably about 10 to 50 mg / m ² , and more preferably 15 to 50 mg / m ² , from the viewpoint of improving the moldability of the electronic packaging material. About 40 mg / m ² .

  The thickness of the heat-fusible resin layer 4 is not particularly limited as long as it functions as a heat-fusible resin layer, but is, for example, about 100 μm or less, preferably about 85 μm or less, and more preferably about 15 to 85 μm. Is mentioned. In addition, for example, when the thickness of the adhesive layer 5 described later is 10 μm or more, the thickness of the heat-fusible resin layer 4 is preferably about 85 μm or less, more preferably about 15 to 65 μm, for example. When the thickness of the later-described adhesive layer 5 is less than 10 μm or when the adhesive layer 5 is not provided, the thickness of the heat-fusible resin layer 4 is preferably about 20 μm or more, more preferably 35 to 85 μm. Degree.

[Adhesive layer 5]
In the battery packaging material of the present invention, the adhesive layer 5 is a layer provided as needed between the barrier layer 3 and the heat-fusible resin layer 4 in order to firmly adhere them to each other.

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

  From the viewpoint of improving the adhesion between the barrier layer 3 (or the acid-resistant film) and the heat-fusible resin layer 4, the adhesive layer 5 preferably contains an acid-modified polyolefin. The acid-modified polyolefin is a polymer obtained by modifying a polyolefin by block polymerization or graft polymerization with an acid component such as carboxylic acid. Examples of the acid component used for the modification include carboxylic acids such as maleic acid, acrylic acid, itaconic acid, crotonic acid, maleic anhydride, and itaconic anhydride, and anhydrides thereof. 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; homopolypropylene, block copolymers of polypropylene (for example, block copolymers of propylene and ethylene), and polypropylenes. Polypropylene such as a random copolymer (for example, a random copolymer of propylene and ethylene); and a terpolymer of ethylene-butene-propylene. Among these polyolefins, polyethylene and polypropylene are preferred.

  In the adhesive layer 5, among the acid-modified polyolefins, a maleic anhydride-modified polyolefin, and particularly a maleic anhydride-modified polypropylene, are preferable.

  Further, from the viewpoint of reducing the thickness of the battery packaging material and obtaining a battery packaging material having excellent shape stability after molding, the adhesive layer 5 is formed by curing a resin composition containing an acid-modified polyolefin and a curing agent. It is more preferable that it is a substance. Preferred examples of the acid-modified polyolefin include those described above.

  The adhesive layer 5 is 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. Preferably, the cured product is 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. Further, the adhesive layer 5 preferably includes at least one selected from the group consisting of a urethane resin, an ester resin, and an epoxy resin, and more preferably includes a urethane resin and an epoxy resin. As the ester resin, for example, an amide ester resin is preferable. The amide ester resin is generally formed by a reaction between a carboxyl group and 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 the case where an unreacted product of a compound having an isocyanate group, a compound having an oxazoline group, and a curing agent such as an epoxy resin remains in the adhesive layer 5, the presence of the unreacted product is determined by, for example, infrared spectroscopy. It can be confirmed by a method selected from Raman spectroscopy, time-of-flight secondary ion mass spectrometry (TOF-SIMS), and the like.

  Further, from the viewpoint of further improving the adhesion between the barrier layer 3 (or the acid-resistant coating), the heat-fusible resin layer 4 and the adhesive layer 5, the adhesive layer 5 includes an oxygen atom, a heterocyclic ring, a C = N bond, It is preferably a cured product of a resin composition containing a curing agent having at least one selected from the group consisting of C—O—C bonds. Examples of the curing agent having a heterocyclic ring include a curing agent having an oxazoline group and a curing agent having an epoxy group. Examples of the curing agent having a C ＝ N bond include a curing agent having an oxazoline group and a curing agent having an isocyanate group. Examples of the curing agent having a C—O—C bond include a curing agent having an oxazoline group, a curing agent having an epoxy group, and a urethane resin. The fact that the adhesive layer 5 is a cured product of the resin composition containing these curing agents may be determined, for example, by gas chromatography mass spectrometry (GCMS), infrared spectroscopy (IR), time-of-flight secondary ion mass spectrometry (TOF) SIMS) and X-ray photoelectron spectroscopy (XPS).

  The compound having an isocyanate group is not particularly limited, but from the viewpoint of effectively improving the adhesion between the acid-resistant film and the adhesive layer 5, a polyfunctional isocyanate compound is preferably used. The polyfunctional isocyanate compound is not particularly limited as long as it is a compound having two or more isocyanate groups. Specific examples of the polyfunctional isocyanate curing agent include pentane diisocyanate (PDI), isophorone diisocyanate (IPDI), hexamethylene diisocyanate (HDI), tolylene diisocyanate (TDI), and diphenylmethane diisocyanate (MDI). And mixtures thereof, copolymers with other polymers, and the like.

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

  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 Epocross series manufactured by Nippon Shokubai Co., Ltd.

  The proportion of the compound having an oxazoline group in the adhesive layer 5 is preferably in the range of 0.1 to 50% by mass, and more preferably in the range of 0.5 to 40% by mass in the resin composition constituting the adhesive layer 5. Is more preferable. Thereby, the adhesion between the barrier layer 3 (or the acid-resistant film) and the adhesive layer 5 can be effectively increased.

  The epoxy resin is not particularly limited as long as it is a resin capable of forming a crosslinked structure by an epoxy group present in the molecule, and a known epoxy resin 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 further 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 the condition using polystyrene as a standard sample.

  Specific examples of the epoxy resin include glycidyl ether derivatives of trimethylolpropane, bisphenol A diglycidyl ether, modified bisphenol A diglycidyl ether, novolak glycidyl ether, glycerin polyglycidyl ether, and polyglycerin polyglycidyl ether. One type of epoxy resin may be used alone, or two or more types may be used in combination.

  The proportion of the epoxy resin in the adhesive layer 5 is preferably in the range of 0.1 to 50% by mass, more preferably in the range of 0.5 to 40% by mass in the resin composition constituting the adhesive layer 5. Is more preferred. Thereby, the adhesion between the barrier layer 3 (or the acid-resistant film) and the adhesive layer 5 can be effectively increased.

  In the present invention, the adhesive layer 5 is 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. In the case of a product, the acid-modified polyolefin functions as a 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.

  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 or more carbodiimide groups is preferable.

  From the viewpoint of enhancing the adhesion between the barrier layer 3 and the heat-fusible resin layer 4 by the adhesive layer 5, the curing agent may be composed of two or more compounds.

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

  Furthermore, the adhesive layer 5 can be suitably formed using, for example, an adhesive. Examples of the adhesive include a non-crystalline polyolefin resin (A) having a carboxyl group, a polyfunctional isocyanate compound (B), and a tertiary amine having no functional group that reacts with the polyfunctional isocyanate compound (B) ( C), and contains the polyfunctional isocyanate compound (B) in a range in which the amount of the isocyanate group is 0.3 to 10 mol with respect to 1 mol of the carboxyl group, and 1 mol of the carboxyl group. And those formed from the adhesive composition containing the tertiary amine (C) in a range of 1 to 10 mol. The adhesive contains a styrene-based thermoplastic elastomer (A), a tackifier (B), and a polyisocyanate (C), and contains a styrene-based thermoplastic elastomer (A) and a tackifier (B). ), The styrene-based thermoplastic elastomer (A) is contained in an amount of 20 to 90% by weight, and the tackifier (B) is contained in an amount of 10 to 80% by weight. Having an active hydrogen derived from an amino group or a hydroxyl group of 0.003 to 0.04 mmol / g, and the tackifier (B) based on 1 mol of the active hydrogen derived from the styrene-based thermoplastic elastomer (A). The active hydrogen derived from the functional group is 0 to 15 mol, and the polyisocyanate (C) contains the active hydrogen derived from the styrene-based thermoplastic elastomer (A) and the active hydrogen derived from the tackifier (B). The total one mole of the sexual hydrogen, an isocyanate group also such as those formed by the adhesive composition consisting of those that are included within an amount of 3-150 mol.

The thickness of the adhesive layer 5 is not particularly limited as long as it functions as an adhesive layer, but is, 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 further more preferably about 5 μm or less. And the lower limit is about 0.1 μm or more, about 0.5 μm or more, about 10 μm or more, and the thickness is preferably about 0.1 to 50 μm or 0.1 to 40 μm. About 0.1-30 μm, about 0.1-20 μm, about 0.1-5 μm, about 0.5-50 μm, about 0.5-40 μm, about 0.5-30 μm, about 0.5-20 μm , About 0.5 to 5 μm, about 10 to 50 μm, about 10 to 40 μm, about 10 to 30 μm, and about 10 to 20 μm. More specifically, if the adhesive exemplified in the adhesive layer 2 is used, the thickness is preferably about 2 to 10 μm, more preferably about 2 to 5 μm. When the resin exemplified in the heat-fusible resin layer 4 is used, the thickness is preferably about 2 to 50 μm, more preferably about 10 to 40 μm. In the case of a cured product of an acid-modified polyolefin and a curing agent, the thickness is preferably about 30 μm or less, more preferably about 0.1 to 20 μm, and still more preferably about 0.5 to 5 μm. In the case of an adhesive layer formed from the above-mentioned adhesive composition, the thickness after drying and curing is about 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.

  As will be described later, in the production of a laminate constituting the battery packaging material of the present invention, as a method of laminating the adhesive layer 5 and the heat-fusible resin layer 4 on the barrier layer 3 in this order, a barrier layer A method in which the adhesive layer 5 and the heat-fusible resin layer 4 are laminated by co-extrusion on the adhesive layer 5 can be adopted. That is, in the battery packaging material of the present invention, the adhesive layer and the heat-fusible resin layer may be a co-extruded laminate.

3. Method for Producing Battery Packaging Material The method for producing the battery packaging material of the present invention is not particularly limited as long as a laminate in which each layer having a predetermined composition is laminated can be obtained. The method for producing the battery packaging material includes, for example, a step of obtaining a laminate by stacking at least the base layer, the barrier layer, and the heat-fusible resin layer located on the outermost surface in this order. And the outermost surface of the substrate layer is constituted by a polyester film layer, and, as a polyester film, using a total reflection method of Fourier transform infrared spectroscopy, on the surface of the polyester film, from 0 ° to 180 ° When infrared absorption spectra in 18 directions are acquired at intervals of 10 °, the ratio of the absorption peak intensity Y _{1340 at 1340} cm ⁻¹ of the infrared absorption spectrum to the absorption peak intensity Y _{1410 at 1410} cm ⁻¹ (Y ₁₃₄₀ / Y ₁₄₁₀ ) is a method in which the ratio of the maximum value Y _{max to the} minimum value Y _min (the degree of surface orientation: Y _max / Y _min ) is less than 1.4.

  An example of the method for producing the battery packaging material of the present invention is as follows. First, a laminate in which the base material layer 1, the adhesive layer 2, and the barrier layer 3 are sequentially laminated (hereinafter, sometimes referred to as “laminate A”) is formed. Specifically, the laminate A is formed by applying an adhesive used for forming the adhesive layer 2 on the base material layer 1 or on the barrier layer 3 whose surface is subjected to a chemical conversion treatment, if necessary, by a gravure coating method, After coating and drying by a coating method such as a roll coating method, the coating can be performed by a dry lamination method in which the barrier layer 3 or the base material layer 1 is laminated and the adhesive layer 2 is cured.

  Next, the adhesive layer 5 and the heat-fusible resin layer 4 are laminated on the barrier layer 3 of the laminate A in this order. For example, (1) a method in which the adhesive layer 5 and the heat-fusible resin layer 4 are laminated by co-extrusion on the barrier layer 3 of the laminate A (co-extrusion laminating method); A laminate formed by laminating the heat-fusible resin layer 4 and the heat-fusible resin layer 4 and laminating the laminate on the barrier layer 3 of the laminate A by a thermal laminating method; (3) bonding the laminate on the barrier layer 3 of the laminate A The adhesive for forming the layer 5 is laminated by an extrusion method or solution coating, dried at a high temperature, or baked, or the like, and the heat-fusible resin layer 4 previously formed into a sheet is formed on the adhesive layer 5. A method of laminating by a thermal lamination method, (4) bonding while laminating the melted adhesive layer 5 between the barrier layer 3 of the laminate A and the heat-fusible resin layer 4 formed in a sheet shape in advance. Laminate A and heat-fusible resin layer 4 are pasted through layer 5 The method (sandwich lamination method), and the like to match.

  As described above, a laminate including the base material layer 1 / the adhesive layer 2 provided as required / the barrier layer 3 whose surface is subjected to chemical conversion treatment as required / the adhesive layer 5 / the heat-fusible resin layer 4 Although a body is formed, in order to strengthen the adhesiveness of the adhesive layer 2 or the adhesive layer 5, it may be further subjected to a heat treatment such as a hot roll contact type, a hot air type, a near infrared type or a far infrared type. Good. Conditions for such a heat treatment include, for example, about 150 to 250 ° C. for about 1 to 5 minutes.

  In the battery packaging material of the present invention, each layer constituting the laminate improves or stabilizes the film forming property, lamination processing, and suitability for secondary processing of the final product (pouching, embossing) as required. For this purpose, a surface activation treatment such as a corona treatment, a blast treatment, an oxidation treatment, and an ozone treatment may be performed.

4. Use of Battery Packaging Material The battery packaging material of the present invention is used for a package for hermetically containing a battery element such as a positive electrode, a negative electrode, and an electrolyte. That is, a battery can be formed by housing a battery element having at least a positive electrode, a negative electrode, and an electrolyte in a package formed of the battery packaging material of the present invention. The battery packaging material of the present invention is suitably used for applications in which printing is performed on the surface of the polyester film layer located on the outermost surface.

  Specifically, at least a positive electrode, a negative electrode, and a battery element provided with an electrolyte, the battery packaging material of the present invention, in a state where the metal terminals connected to each of the positive electrode and the negative electrode protrude outward, A battery is formed by forming a flange (a region where the heat-fusible resin layers are in contact with each other) around the periphery of the element so as to be formed, and heat-sealing the heat-fusible resin layers of the flange to seal them. There is provided a battery using the packaging material. When the battery element is accommodated in the package formed of the battery packaging material of the present invention, the heat-fusible resin portion of the battery packaging material of the present invention is located inside (the surface in contact with the battery element). To form a package. In addition, the measurement of the infrared absorption spectrum and the arithmetic average roughness Ra on the surface of the polyester film layer is obtained by obtaining a battery packaging material from a battery and measuring the polyester film layer of the obtained battery packaging material. Can be. However, the measurement of the infrared absorption spectrum and the arithmetic average roughness Ra of the battery packaging material obtained from the battery was performed by measuring the peripheral flange of the battery (the portion where the heat-fusible resin layers were thermally fused to each other). ) Or a portion different from the side portion (preferably, the top or bottom surface of the battery) is measured.

  In the present invention, in a package formed by the battery packaging material of the present invention, at least a positive electrode, a negative electrode, and a housing step of housing a battery element having an electrolyte, and at least one of before and after the housing step , A step of performing printing on the surface of the polyester film layer located on the outermost surface can produce a battery having the surface of the polyester film layer printed thereon. That is, the battery of the present invention can be a battery having a printed portion on the surface. The printing portion is a portion on which a barcode, a pattern, characters, symbols, and the like formed on the surface of the battery are printed.

  In the battery packaging material of the present invention, when the evaluation of the printability of the polyethylene terephthalate film surface is performed under the following conditions, the radius of the dots forming the print portion is preferably 130 μm or more, 135 μm or more, or 140 μm or more. Further, the radius is preferably 151 μm or less and 149 μm or less, and the preferable range of the radius is about 130 to 151 μm, about 130 to 149 μm, about 135 to 151 μm, about 135 to 149 μm, about 140 to 151 μm, or about 140 to 149 μm Degree. When the radius of the dot satisfies such a value, it can be evaluated that the printability is excellent. Specifically, printing of barcodes, patterns, characters, symbols, etc. is formed by a group of ink dots, and if the radius of the dots forming the printing portion satisfies the above value, the radius of the dots is too small. The desired printing can be appropriately performed without being too large or too large.

  Further, in the battery packaging material of the present invention, when the suitability for printing on the surface of the polyethylene terephthalate film was evaluated under the following conditions, the circularity of the dots forming the printed portion may be 0.725 or more. preferable. It can be evaluated that the closer the circularity of the printed portion is to 1, the more excellent the printability is. Specifically, printing of barcodes, patterns, characters, symbols, and the like, if the circularity of the dots forming the printing portion satisfies the above value, the shape of the dots is not distorted, and the desired printing is appropriately performed. be able to.

<Evaluation of printability of polyethylene terephthalate film surface>
In an environment of a temperature of 24 ° C. and a relative humidity of 50%, the ink is applied to the surface of the polyethylene terephthalate film of each of the battery packaging materials prepared above using an ink jet printer (9040 (1.1M head, manufactured by Markem-Imaj KK)). And dried for 10 seconds. Next, the suitability for printing on the surface of the polyethylene terephthalate film is evaluated based on the radius and circularity of the dots of the printing portion formed on the surface of the polyethylene terephthalate film. The print setting conditions are as follows: ink viscosity: 3.4 cps, temperature: 34 ° C., pressure: 270 bar, nozzle size: diameter 50 μm, and resolution (dot density): 115 dpi. The method for measuring the radius and circularity of the dots in the printing section is as described below. The evaluation is performed in the state of the battery packaging material. In addition, the radius and circularity of the dots in the printing section are average values of N = 3. In performing the evaluation, operations such as wiping the surface of the polyethylene terephthalate film are not performed.

  The distance between the print head of the inkjet printer and the surface of the polyethylene terephthalate film was 20 mm, and 5157E standard ink was used as the ink.

  In addition, a laser microscope (for example, a laser microscope VK-9710 manufactured by KEYENCE) is used for observing the radius and circularity of the dots of the printed portion formed on the surface of the polyethylene terephthalate film, and the magnification is set to 10 times.

(How to measure the radius of the dots in the print area)
The shape of the dot of the printed portion dropped on the surface of each polyethylene terephthalate film was determined using an image analysis software (for example, KEYENCE analysis software VK Analyzer Ver2.4.0.0) for the image observed with the laser microscope. The radius of the circle passing through the three points (= the radius of the dots in the print portion) is determined by the analysis using the three-point circle.

(Evaluation of the circularity of the dots in the printing section)
The circularity of the dots of the printed portion formed by the ink dropped on the surface of each polyethylene terephthalate film is measured using image analysis software (for example, image analysis software WinROOF (Ver 6.6.0) manufactured by Mitani Corporation). . Note that the analysis is performed on a figure connecting the center points of the boundary pixels forming the contour of the dot. On the analysis screen of WinRoof, the value is displayed as circularity II. In addition, the circularity of the dots in the printing section is calculated by the following equation.
The circularity of the dots in the print section = 4π x (area of the dot) / (perimeter of the dot) ²

  The battery packaging material of the present invention may be used for any of a primary battery and a secondary battery, but is preferably a secondary battery. The type of the secondary battery to which the battery packaging material of the present invention is applied is not particularly limited, and examples thereof include a lithium ion battery, a lithium ion polymer battery, a lead storage battery, a nickel-hydrogen storage battery, a nickel-cadmium storage battery, and a nickel-cadmium storage battery. Examples include an iron storage battery, a nickel-zinc storage battery, a silver oxide-zinc storage battery, a metal-air battery, a polyvalent cation battery, a capacitor, and a capacitor. Among these secondary batteries, suitable applications of the battery packaging material of the present invention include lithium ion batteries and lithium ion polymer batteries.

5. Polyester Film The polyester film of the present invention is a polyester film used for the polyester film layer located on the outermost surface of the battery packaging material. Polyester film of the present invention, using the total reflection method of Fourier transform infrared spectroscopy, for the surface of the polyester film, when obtaining an infrared absorption spectrum in 18 directions from 0 ° to 170 ° in steps of 10 °, It is characterized by satisfying Y _max / Y _min <1.4. The specific structure (composition, thickness, etc.) of the polyester film of the present invention is the same as the polyester film of the polyester film layer constituting the outermost surface in the above-mentioned “2. Each layer forming the battery packaging material”. . In addition, the measurement of the infrared absorption spectrum on the surface of the polyester film can be performed on the outermost surface side of the battery packaging material with only the polyester film. The measurement of the arithmetic average roughness Ra of the polyester film can also be performed on the outermost surface of the battery packaging material in the state of the polyester film alone.

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

<Manufacture of battery packaging materials>
The battery packaging materials of Examples 1 to 3 and Comparative Examples 1 to 7 were produced by the following methods.

(Example 1)
Aluminum having an acid-resistant film formed on both sides on a biaxially stretched polyethylene terephthalate film (having a thickness of 25 μm, having a degree of surface orientation of _Ymax / _Ymin and an arithmetic average roughness Ra of Table 1) as a base material layer A barrier layer made of foil (JIS H4160: 1994 A8021H-O, thickness: 40 μm) was laminated by a dry lamination method. Specifically, a two-component curable urethane adhesive (a polyol compound and an aromatic isocyanate compound) is applied to one surface of an aluminum foil, and an adhesive layer (thickness: 3 μm) is formed on the aluminum foil having an acid-resistant film formed on both surfaces. ) Formed. Next, after laminating the adhesive layer on the aluminum foil and the biaxially stretched polyethylene terephthalate film, an aging treatment was performed to produce a laminate of the base material layer / adhesive layer / barrier layer. In addition, the chemical conversion treatment for forming the acid-resistant film of the aluminum foil used as the barrier layer is performed by applying a treatment solution comprising a phenol resin, a chromium fluoride compound, and phosphoric acid to a coating amount of chromium of 10 mg / m ² (dry mass). The coating was performed by applying the coating on both sides of an aluminum foil by a roll coating method and baking the coating. The aluminum foil used as the barrier layer has an acid-resistant film containing chromium oxide and phosphate.

  Next, maleic anhydride-modified polypropylene (thickness 25 μm) as an adhesive layer and random polypropylene (thickness 55 μm) as a heat-fusible resin layer were co-extruded on the barrier layer of the obtained laminate. By doing so, the adhesive layer / heat-fusible resin layer was laminated on the barrier layer. Next, by aging and heating the obtained laminate, the base layer / adhesive layer / barrier layer having an acid-resistant coating on both sides / adhesive layer / heat-fusible resin layer are laminated in this order. A battery packaging material was obtained.

The analysis of the acid-resistant film was performed as follows. First, the space between the barrier layer and the adhesive layer was peeled off. At this time, they were physically separated without using water, an organic solvent, an aqueous solution of an acid or an alkali, or the like. After the separation between the barrier layer and the adhesive layer, since the adhesive layer remained on the surface of the barrier layer, the remaining adhesive layer was removed by etching with Ar-GCIB. The surface of the barrier layer thus obtained was analyzed for an acid-resistant film using time-of-flight secondary ion mass spectrometry. As a result, the acid-resistant ^{_{coating, Ce 2 PO 4 +, CePO}} 4 - secondary ions consisting of Ce and P and O, such as have been detected. Details of the measuring device and measuring conditions of the time-of-flight secondary ion mass spectrometry are as follows.

Measurement device: Time-of-flight secondary ion mass spectrometer TOF. Manufactured by ION-TOF. SIMS5
Measurement conditions the primary ion: a double-charge ions of bismuth cluster (Bi ₃ ⁺⁺⁾
Primary ion accelerating voltage: 30 kV
Mass range (m / z): 0 to 1500
Measuring range: 100 μm × 100 μm
Number of scans: 16 scan / cycle
Number of pixels (one side): 256 pixels
Etching ion: Ar gas cluster ion beam (Ar-GCIB)
Etching ion acceleration voltage: 5.0 kV

(Example 2)
On the surface of a biaxially stretched polyethylene terephthalate film (thickness 25 μm, having a surface orientation degree of Table 1: Y _max / Y _min and arithmetic average roughness Ra), a lubricant (erucamide (coating amount: 6 mg / m ² )) A battery packaging material was obtained in the same manner as in Example 1, except that polyether-modified silicone oil (application amount was 1 mg / m ² ) was applied (application amount was 7 mg / m ^{2 in} total).

(Example 3)
As a substrate layer, a biaxially oriented polyethylene terephthalate film (thickness: 12 μm, having a surface orientation degree in Table 1 having Y _max / Y _min and arithmetic average roughness Ra) and a biaxially oriented nylon film (thickness: 15 μm) are dry-laminated. A laminated film laminated by the method was prepared. In the laminated film, the biaxially stretched polyethylene terephthalate film and the biaxially stretched nylon film are bonded with a urethane adhesive (thickness after curing is 3 μm) using a polyol and an isocyanate curing agent. Next, a chemical conversion treatment is applied to both sides of the biaxially stretched nylon film to form a barrier layer composed of an aluminum foil (JIS H4160: 1994 A8021H-O, thickness: 40 μm) having an acid-resistant film by dry lamination. Laminated. Specifically, a two-component polyurethane adhesive (a polyol compound and an aromatic isocyanate compound) is applied to one surface of an aluminum foil provided with an acid-resistant film, and an adhesive layer (thickness: 3 μm) is formed on the aluminum foil. Formed. Next, after laminating the adhesive layer on the aluminum foil and the biaxially stretched nylon film side of the base material layer, an aging treatment is carried out, whereby the base material layer (biaxially stretched polyethylene terephthalate film / adhesive / biaxial A laminate of (stretched nylon film) / adhesive layer / barrier layer having an acid-resistant film on both sides was prepared. The aluminum foil used as the barrier layer has an acid-resistant film containing chromium oxide and phosphate on both surfaces. The analysis of the acid-resistant film on the barrier layer was performed using time-of-flight secondary ion mass spectrometry, as in Example 1. As a result, the acid-resistant coating, CrPO ₂ ^+, CrPO ₄ ^- secondary ions of Cr and P and O, such as have been detected.

  Next, a maleic anhydride-modified polypropylene (thickness: 40 μm) as an adhesive layer and a random polypropylene (thickness: 40 μm) as a heat-fusible resin layer were co-extruded on the barrier layer of the obtained laminate. By doing so, the adhesive layer / heat-fusible resin layer was laminated on the barrier layer. Next, the obtained laminate was aged and heated to obtain a battery packaging material in which a base material layer / adhesive layer / barrier layer / adhesive layer / heat-fusible resin layer was laminated in this order. .

(Comparative Example 1)
A biaxially stretched polyethylene terephthalate film of the base material layer was prepared in the same manner as in Example 3 except that a film having a surface orientation degree shown in Table 1 of Y _max / Y _min and an arithmetic average roughness Ra was used. A battery packaging material was obtained.

(Comparative Example 2)
A polyethylene terephthalate film and a nylon film were laminated by co-extrusion to prepare a biaxially stretched laminated film. A biaxially oriented polyethylene terephthalate film (having a thickness of 5 μm, having a surface orientation degree of Y _max / Y _min and an arithmetic average roughness Ra of Table 1) and a biaxially oriented nylon film (thickness) of the laminated film constituting the base material layer 20 μm), there is an adhesive layer (1 μm thick) made of polyester (polyester elastomer). In the laminated film, biaxially oriented polyethylene terephthalate film / adhesive / biaxially oriented nylon film are laminated in this order. Next, on the surface on the biaxially stretched nylon film side, a chemical conversion treatment is applied to both surfaces, and a barrier layer composed of an aluminum foil (JIS H4160: 1994 A8021H-O, thickness 40 μm) provided with an acid-resistant film is dry-laminated. It was laminated by the method. Specifically, a two-component polyurethane adhesive (a polyol compound and an aromatic isocyanate compound) was applied to one surface of an aluminum foil provided with an acid-resistant film to form an adhesive layer (thickness: 3 μm). Next, after laminating the adhesive layer on the barrier layer provided with the acid-resistant film and the biaxially stretched nylon film side of the base material layer, an aging treatment is carried out, whereby the base material layer (biaxially stretched polyethylene terephthalate film) is formed. / Adhesive / biaxially stretched nylon film) / adhesive layer / laminated body with barrier layer provided with acid resistant coating on both sides.

  Next, a non-crystalline polyolefin resin having a carboxyl group and an adhesive (having a thickness of 2 μm after curing) made of a polyfunctional isocyanate compound are applied, and dried at 100 ° C. to obtain a barrier layer side of the obtained laminate. Then, an unstretched polypropylene film (CPP, thickness: 80 μm) was passed between two rolls set at 60 ° C. and adhered to laminate the adhesive layer / heat-fusible resin layer on the barrier layer. Next, by performing an aging treatment, the base material layer (biaxially oriented polyethylene terephthalate film / adhesive / biaxially oriented nylon film) / adhesive layer / barrier layer / adhesive layer / unstretched polypropylene film is laminated in this order. The obtained battery packaging material was obtained.

(Comparative Example 3)
A biaxially stretched polyethylene terephthalate film of the base material layer was prepared in the same manner as in Example 3 except that a film having a surface orientation degree shown in Table 1 of Y _max / Y _min and an arithmetic average roughness Ra was used. A battery packaging material was obtained.

(Comparative Example 4)
A biaxially stretched polyethylene terephthalate film of the base material layer was prepared in the same manner as in Example 3 except that a film having a surface orientation degree shown in Table 1 of Y _max / Y _min and an arithmetic average roughness Ra was used. A battery packaging material was obtained.

(Comparative Example 5)
A biaxially stretched polyethylene terephthalate film of the base material layer was prepared in the same manner as in Example 3 except that a film having a surface orientation degree shown in Table 1 of Y _max / Y _min and an arithmetic average roughness Ra was used. A battery packaging material was obtained.

(Comparative Example 6)
A lubricant (erucamide) was applied to the surface of a biaxially stretched polyethylene terephthalate film (thickness: 25 μm, having a surface orientation degree of Table 1: Y _max / Y _min and arithmetic average roughness Ra) (application amount: 7 mg). / M ² ), except that a packaging material for a battery was obtained in the same manner as in Comparative Example 2.

(Comparative Example 7)
A lubricant (erucamide) was applied to the surface of a biaxially stretched polyethylene terephthalate film (thickness: 25 μm, having a degree of surface orientation in Table 1: Y _max / Y _min and arithmetic average roughness Ra) (the amount of application was 10 mg). / M ² ), except that a packaging material for a battery was obtained in the same manner as in Comparative Example 2.

<Measurement of surface orientation>
For the biaxially stretched polyethylene terephthalate film surface (the surface opposite to the barrier layer) of each of the battery packaging materials prepared above, the total reflection method (ATR) of the Fourier transform infrared spectroscopy (FT-IR) was used. The infrared absorption spectrum in 18 directions was acquired from 0 ° to 170 ° in increments of 10 °, and the absorption peak intensity Y ₁₃₄₀ (CH ₂ pitch vibration) at a wave number of ₁₃₄₀ cm ⁻¹ of the infrared absorption spectrum in the 18 directions was obtained. Y ₁₃₄₀ / Y ₁₄₁₀ is calculated from the value of the absorption peak intensity Y ₁₄₁₀ (C = C stretching vibration) at a wave number of ₁₄₁₀ cm ⁻¹ , and the surface orientation degree is calculated from the maximum value Y _max and the minimum value Y _min among these values: _Ymax / _Ymin was calculated. Specific measurement conditions of the infrared absorption spectrum are as follows. Table 1 shows the results.

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

(Measurement conditions of infrared absorption spectrum)
Spectroscope: Nicolet iS10 FT-IR manufactured by Thermo Fisher Scientific
Attached device: Single reflection ATR attached device (Seagull)
Detector: MCT (Hg Cd Te)
Wave number resolution: 8 cm ^-1
Number of accumulation: 128 times IRE: Ge
Incident angle: 30 °
Polarizer: wire-grid, S-polarized light Baseline: absorption peak intensity at average wavenumber 1340 cm ^-1 of the intensity in the wave number range of 1800-2000cm ^-1 Y _1340: the maximum value of the peak intensity in the range of wave number 1335～1342Cm ^-1 absorption peak intensity Y ₁₄₁₀ in the value wavenumber 1410 cm ^-1 obtained by subtracting the baseline values: a value obtained by subtracting the baseline values from the maximum value of the peak intensity in the range of wave number 1400～1410Cm ^-1

  The infrared absorption spectra in 18 directions were obtained by placing the sample with the polyester film exposed horizontally on a sample holder and rotating the Ge crystal placed on the sample by 10 °. The incident angle is the angle between the perpendicular (normal) and the incident light.

<Measurement of arithmetic average roughness Ra of polyethylene terephthalate film surface>
According to the method specified in JIS B 0601-2001, the arithmetic mean roughness of the surface of the biaxially stretched polyethylene terephthalate film (polyester film layer) constituting the outermost surface of each of the battery packaging materials obtained above is described. Ra was measured. As a measuring device of the arithmetic average roughness Ra, a white interferometer NewView7300 manufactured by Zygo Co., Ltd. is used, and the measurement is performed under the conditions of a measurement area of 0.22 mm square (objective lens 50 times, zoom lens 1 time) and inclination correction (Cylinder). Was done. The arithmetic average roughness Ra was measured in a state of the battery packaging material. In the measurement, an operation such as wiping the surface of the polyethylene terephthalate film was not performed. Table 1 shows the results.

<Evaluation of printability of polyethylene terephthalate film surface>
In an environment of a temperature of 24 ° C. and a relative humidity of 50%, an ink jet printing machine (9040 (1.1M head manufactured by Markem Image Co., Ltd.)) was placed on the surface of the biaxially stretched polyethylene terephthalate film of each battery packaging material prepared above. The ink was dropped and dried for 10 seconds. Next, the printability of the surface of the biaxially stretched polyethylene terephthalate film was evaluated based on the radius and circularity of the dots formed on the surface of the biaxially stretched polyethylene terephthalate film. The printing conditions were as follows: ink viscosity: 3.4 cps, temperature: 34 ° C., pressure: 270 bar, nozzle size: diameter 50 μm, and resolution (dot density): 115 dpi. The method for measuring the radius and circularity of the dots in the printing section is as described below. The evaluation was performed in the state of the battery packaging material. Further, the radius and circularity of the dots in the printing section were average values of N = 3. In the evaluation, operations such as wiping the surface of the polyethylene terephthalate film were not performed. Table 1 shows the results.

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

  The observation of the radius and circularity of the dots of the printed portion formed on the surface of the biaxially stretched polyethylene terephthalate film was performed using a laser microscope (Laser microscope VK-9710 manufactured by KEYENCE) at a magnification of 10 times. For reference, in Example 2 and Comparative Example 7, images of the printed portion formed on the surface of the biaxially stretched polyethylene terephthalate film observed with a laser microscope are shown in FIGS. 4 (Example 2) and 5 (Comparative Example), respectively. It is shown in 7).

(Method of measuring the radius of the dots in the print section)
The dot shape of the printed portion dropped on the surface of each biaxially stretched polyethylene terephthalate film was determined by using a KEYENCE analysis software VK Analyzer Ver. , The radius of a circle passing through three points (= the radius of the dot in the print portion) was determined. Table 1 shows the results.

(Evaluation of the circularity of dots in the printing section)
The circularity of the dots in the printed portion formed by the ink dropped on the surface of each biaxially stretched polyethylene terephthalate film was measured using the image analysis software WinROOF (Ver 6.6.0) manufactured by Mitani Corporation. The analysis was performed on a figure connecting the center points of the boundary pixels constituting the contour of the dot. On the analysis screen of WinRoof, the value is displayed as circularity II. In addition, the circularity of the dots in the printing section is calculated by the following equation. The circularity of the dots in the printed area was evaluated according to the following criteria. Table 1 shows the results. For reference, Table 1 shows the measured values of the circularity of the dots in the printed portion for Example 2 (FIG. 4) and Comparative Example 7 (FIG. 5).
The circularity of the dots in the print section = 4π x (area of the dot) / (perimeter of the dot) ²
A: The circularity of the dots in the printed portion is 0.725 or more, and the dots in the printed portion have a beautiful circle on the surface of the biaxially stretched polyethylene terephthalate film.
B: The circularity of the dots in the printed portion is 0.700 or more and less than 0.725, and the dots in the printed portion have a distorted circle on the surface of the biaxially stretched polyethylene terephthalate film.

In the packaging materials for batteries of Examples 1 to 3, the polyester film layer constituting the outermost surface satisfies the relationship of the formula: Y _max / Y _min <1.4, and the radius of the dot in the printing portion is small. In addition, the evaluation of the circularity of the dots in the printed portion was excellent, and the printability was excellent. From the results of Examples 1 to 3, it can be seen that excellent printability is exhibited regardless of whether a lubricant is present on the surface of the polyester layer. On the other hand, in the packaging materials for batteries of Comparative Examples 1 to 7, the polyester film layer constituting the outermost surface did not satisfy the relationship of the formula: Y _max / Y _min <1.4, and the printing portion The dot radius was large or the evaluation of 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 printing portion was small, the circularity was as small as 0.723, and the dots in the printing portion had a distorted circle on the surface of the polyethylene terephthalate film layer. (See FIG. 5). In Comparative Example 6, the lubricant is present on the surface of the polyester layer, and the radius of the dots in the printed portion is substantially the same as that in Comparative Example 2, but the radius of the dots in the printed portion is larger than in Examples 1 to 3, Printability was poor. Further, in Comparative Example 7 in which the amount of the lubricant was increased as compared with Comparative Example 6, although the radius of the dots in the printing portion was small as described above, the dots in the printing portion had a distorted circular shape and were poor in printability. .

DESCRIPTION OF SYMBOLS 1 Base material layer 2 Adhesive layer 3 Barrier layer 4 Heat-fusible resin layer 5 Adhesive layer

Claims (1)

At least, a base material layer located on the outermost surface, a barrier layer, and a heat-fusible resin layer, which is composed of a laminate including in this order,
The outermost surface of the base material layer is constituted by a polyester film layer,
When the surface of the polyester film layer is subjected to infrared absorption spectra in 18 directions from 0 ° to 170 ° in increments of 10 ° using the total reflection method of Fourier transform infrared spectroscopy, the following formula is satisfied. , Battery packaging materials.
Y _max / Y _min <1.4
Y _max is the maximum value among the values obtained by dividing the absorption peak intensity Y ₁₃₄₀ at the wave number of ₁₃₄₀ cm ⁻¹ of the infrared absorption spectrum by the absorption peak intensity Y ₁₄₁₀ at the wave number of ₁₄₁₀ cm ⁻¹ in each of the 18 directions. It is.
Y _min is the minimum value among the values obtained by dividing the absorption peak intensity Y ₁₃₄₀ at the wave number of ₁₃₄₀ cm ⁻¹ of the infrared absorption spectrum by the absorption peak intensity Y ₁₄₁₀ at the wave number of ₁₄₁₀ cm ⁻¹ in each of the 18 directions. It is.