JP6672600B2 - Battery packaging material - Google Patents

Description

  TECHNICAL FIELD The present invention relates to a battery packaging material having high piercing strength, excellent electrolytic solution resistance and excellent moldability.

  Conventionally, various types of batteries have been developed, but in all batteries, a packaging material is an indispensable member for sealing battery elements such as electrodes and electrolytes. Conventionally, metal packaging materials have been widely used for battery packaging, but in recent years, with the increasing performance of electric vehicles, hybrid electric vehicles, personal computers, cameras, mobile phones, etc., batteries are required to have various shapes. At the same time, there is a demand for a thinner and lighter weight. 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, a film-like laminate in which a base layer / metal layer / sealant layer is sequentially laminated has been proposed as a battery packaging material that can be easily processed into various shapes and that can be reduced in thickness and weight. (For example, see Patent Document 1). In such a battery packaging material, generally, a concave portion is formed by cold forming, and a battery element such as an electrode or an electrolytic solution is disposed in a space formed by the concave portion, and the sealant layers are thermally welded to each other. Thereby, a battery in which the battery element is accommodated inside the battery packaging material is obtained.

  From the viewpoint of, for example, excellent formability of the battery packaging material, in such a film-like laminate, an aluminum foil is widely used as a metal layer.

JP 2008-287971 A

  In recent years, in order to further increase the energy density of a battery and to further reduce the size of the battery, further reduction in the thickness of the battery packaging material has been required. On the other hand, when manufacturing a battery, transporting or using a product on which the battery is mounted, a large impact may be applied to the product. At this time, a large external force may be applied to the battery packaging material containing the battery element from inside or outside.

  As described above, along with the demand for thinner packaging materials for batteries, thinning of the metal layer is also being studied. Aluminum, however, has excellent moldability, but has low rigidity and is large from the inside or outside of the packaging material for batteries. When an external force is applied, a hole is formed in the aluminum, and the battery element may be exposed to the outside.

  Under such circumstances, it is conceivable to use a highly rigid metal such as stainless steel or titanium steel instead of aluminum. However, in general, stainless steel has high rigidity (piercing strength), but has low moldability, and thus has a problem that pinholes and cracks are easily generated in the stainless steel foil when molding a battery packaging material. I have. For this reason, at present, stainless steel foil is hardly used for thin battery packaging materials.

  The main object of the present invention is to provide a packaging material for a battery having high piercing strength, excellent electrolytic solution resistance and excellent moldability, even though stainless steel foil is laminated on the laminate. I do.

  The present inventors have conducted intensive studies in order to solve the above problems, at least, a battery packaging material comprising a laminate having a base layer, a stainless steel foil, and a sealant layer in this order, the stainless steel Since a chemical conversion treatment layer resistant to hydrogen fluoride is formed on at least the sealant layer side of the steel foil, a piercing strength is high, and a battery packaging material having excellent electrolytic solution resistance and excellent moldability is obtained. Was found.

  Further, the present inventors have proposed a battery packaging material using an austenitic stainless steel foil as a stainless steel foil, a battery packaging material provided with a specific chemical conversion treatment layer, and a battery packaging material having a black base material layer side. Materials and packaging materials for batteries in which the MFR of the sealant layer is set to an upper limit value exhibit excellent effects such as piercing strength, moldability, and electrolytic solution resistance, and heat generated easily by using stainless steel foil. It has been found that deterioration in airtightness due to misalignment of the heat seal surface after sealing and reduction in seal strength can be effectively suppressed.

The present invention has been completed by further study based on the above findings. That is, the present invention provides the following aspects of the invention.
Item 1. At least a base material layer, a stainless steel foil, and a battery packaging material comprising a laminate having a sealant layer in this order,
A packaging material for batteries, wherein a chemical conversion treatment layer resistant to hydrogen fluoride is formed on at least the sealant layer side of the stainless steel foil.
Item 2. Item 2. The battery packaging material according to Item 1, wherein the stainless steel foil is made of austenitic stainless steel.
Item 3. Item 3. The battery packaging material according to item 1 or 2, wherein the stainless steel is SUS304.
Item 4. Item 4. The packaging material for a battery according to any one of Items 1 to 3, wherein the chemical conversion treatment layer is formed by phosphoric acid chromate treatment using a resin.
Item 5. Item 5. The packaging material for a battery according to any one of Items 1 to 4, wherein the resin used for the phosphoric acid chromate treatment is a phenol resin.
Item 6. Item 6. The battery packaging material according to any one of Items 1 to 5, wherein at least one of the layers located on the base material layer side of the stainless steel foil is black.
Item 7. An adhesive layer is laminated between the base material layer and the stainless steel foil,
Item 7. The packaging material for a battery according to any one of Items 1 to 6, wherein the adhesive layer is colored black.
Item 8. Item 8. The battery packaging material according to any one of Items 1 to 7, wherein a melt flow rate (MFR) at 230 ° C of the sealant layer is 15 g / 10 minutes or less.
Item 9. Item 10. The battery packaging material according to any one of Items 1 to 8, further comprising an adhesive layer between the stainless steel foil and the sealant layer.
Item 10. Item 10. The packaging material for a battery according to any one of Items 1 to 9, wherein the stainless steel foil has a thickness of 40 µm or less.
Item 11. Item 10. The packaging material for a battery according to any one of Items 1 to 10, wherein the total thickness of the laminate is 110 µm or less.
Item 12. The total thickness of the laminate is T (μm), the thickness of the stainless steel foil is TS (μm), and the piercing strength of the laminate is F (N), which is measured by a measuring method in accordance with JIS Z 1707 1997. Item 12. The battery packaging material according to any one of Items 1 to 11, wherein F / T is 0.3 (N / μm) or more and F / TS is 0.7 (N / μm) or more.
Item 13. 13. A battery, wherein a battery element including at least a positive electrode, a negative electrode, and an electrolyte is accommodated in the battery packaging material according to any one of Items 1 to 12.

According to the present invention, at least a base material layer, a stainless steel foil, and a battery packaging material comprising a laminate having a sealant layer in this order, wherein at least the sealant layer side of the stainless steel foil has hydrogen fluoride The formation of the resistant chemical conversion layer can provide a packaging material for a battery having high piercing strength, and excellent in electrolyte resistance and moldability.
Further, a battery packaging material using an austenitic stainless steel foil as a stainless steel foil, a battery packaging material provided with a specific chemical conversion treatment layer, a battery packaging material having a black base material layer side, and a MFR of a sealant layer The battery packaging material with the upper limit of the above set exhibits excellent effects of piercing strength, moldability, and electrolyte resistance. Further, it is possible to effectively suppress deterioration in airtightness and reduction in sealing strength due to misalignment of the heat sealing surface after heat sealing, which is easily caused by using a stainless steel foil.

1 is a schematic sectional view of a battery packaging material of the present invention. 1 is a schematic sectional view of a battery packaging material of the present invention.

  The battery packaging material of the present invention is at least a base material layer, a stainless steel foil, and a battery packaging material comprising a laminate having a sealant layer in this order, at least on the sealant layer side of the stainless steel foil, A chemical conversion treatment layer resistant to hydrogen fluoride is formed. Hereinafter, the present invention is referred to as a first embodiment of the present invention.

  Furthermore, in the battery packaging material of the present invention, in addition to the configuration of the above-described first embodiment, a second embodiment in which a specific chemical conversion treatment layer is further provided on the surface of a stainless steel foil, There is a third embodiment in which the black color is black, and a fourth embodiment in which the upper limit of the MFR of the sealant layer is set to a specific value.

  Hereinafter, the first embodiment of the battery packaging material of the present invention will be described in detail, and the configuration added to the first embodiment will be described in the second to fourth embodiments.

(First embodiment)
1. Laminated Structure of Battery Packaging Material The battery packaging material of the present invention comprises a laminate having at least a base layer 1, a stainless steel foil 3, a chemical conversion treatment layer 3b, and a sealant layer 4 in this order. When the battery packaging material is used for a battery, the base material layer 1 becomes the outermost layer and the sealant layer 4 becomes the innermost layer (battery element side). At the time of assembling the battery, the sealant layers 4 located on the periphery of the battery element are brought into contact with each other and thermally welded to seal the battery element, thereby sealing the battery element. As shown in FIG. 1, the battery packaging material of the present invention may have an adhesive layer 2 between a base material layer 1 and a stainless steel foil 3. Further, as shown in FIG. 2, the battery packaging material of the present invention may have an adhesive layer 5 between the stainless steel foil 3 and the sealant layer 4.

  Further, the battery packaging material of the present invention may have a chemical conversion treatment layer 3 a on the surface of the stainless steel foil 3 on the side of the base material layer 1. 1 and 2, a chemical conversion treatment layer 3a is laminated on the surface of the stainless steel foil 3 on the base material layer 1 side, and a chemical conversion treatment layer 3b is formed on the surface of the stainless steel foil 3 on the sealant layer 4 side. It is laminated.

2. Composition of each layer forming battery packaging material [base layer 1]
In the battery packaging material of the present invention, the base material layer 1 is a layer that forms the outermost layer. The material for forming the base material layer 1 is not particularly limited as long as it has insulating properties. As a material for forming the base material layer 1, for example, polyester resin, polyamide resin, epoxy resin, acrylic resin, fluororesin, polyurethane resin, silicon resin, phenol resin, polyetherimide resin, polyimide resin, polyolefin resin, and the like Mixtures and copolymers are exemplified.

  As the polyester resin, specifically, polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polybutylene naphthalate, polyethylene isophthalate, polycarbonate, copolymerized polyester having a main unit of ethylene terephthalate and a repeating unit of butylene terephthalate And the like, which is mainly a copolymerized polyester. 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 is excellent in electrolytic solution resistance and has an advantage that whitening or the like hardly occurs upon adhesion of the electrolytic solution, and thus is preferably used as a material for forming the base material layer 1.

  Further, as the polyamide resin, specifically, aliphatic polyamides such as nylon 6, nylon 66, nylon 610, nylon 12, nylon 46, a copolymer of nylon 6 and nylon 6,6; terephthalic acid and / or And hexamethylenediamine-isophthalic acid-terephthalic acid copolymerized polyamide such as nylon 6I, nylon 6T, nylon 6IT, and nylon 6I6T (I represents isophthalic acid and T represents terephthalic acid) containing a structural unit derived from isophthalic acid; Polyamides containing aromatics such as taxylylene adipamide (MXD6); alicyclic polyamides such as polyaminomethylcyclohexyl adipamide (PACM6); and lactam components and isocyanate components such as 4,4'-diphenylmethane-diisocyanate. Copolymerized polyamide, Polyester amide copolymer and polyether ester amide copolymer is a copolymer of polymerized polyamide and polyester and polyalkylene ether glycol; copolymers thereof, and the like. These polyamides may be used alone or in a combination of two or more. The stretched polyamide film is excellent in stretchability, can prevent whitening due to resin cracking of the base layer 1 during molding, and is suitably used as a material for forming the base layer 1.

  The base material layer 1 may be formed of a uniaxially or biaxially stretched resin film, or may be formed of an unstretched resin film. Above all, a uniaxially or biaxially stretched resin film, particularly a biaxially stretched resin film, is preferably used as the base material layer 1 because heat resistance is improved by orientation crystallization. Further, the base material layer 1 may be formed by coating the above-mentioned material on the stainless steel foil 3.

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

  The base material layer 1 may be formed by laminating at least one of a resin film and a coating of a different material in order to improve the pinhole resistance and the insulation when the battery is packaged. Specific examples include a multilayer structure in which a polyester film and a nylon film are laminated, and a multilayer structure in which biaxially stretched polyester and biaxially stretched nylon are laminated. When the base material layer 1 has a multilayer structure, the resin films 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 sand lamination method, and 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. Further, the bonding mechanism of the adhesive is not particularly limited, and may be any of a chemical reaction type, a solvent volatilization type, a hot-melt type, a hot pressure type, and an electron beam curing type such as UV and EB. As a component of the adhesive, polyester resin, polyether resin, polyurethane resin, epoxy resin, phenol resin, polyamide resin, polyolefin resin, polyvinyl acetate resin, cellulose resin, (meth) acrylic resin Resin, polyimide resin, amino resin, rubber, silicon resin, and fluorine resin are exemplified.

  The base material layer 1 may be reduced in friction in order to improve moldability. When the friction of the base material layer 1 is reduced, the friction coefficient of the surface thereof is not particularly limited, but may be, for example, 1.0 or less. In order to reduce the friction of the base material layer 1, for example, a mat treatment, formation of a thin film layer of a slip agent, a combination thereof, and the like can be given. Alternatively, a resin layer may be formed and applied. These resins include polyester resins, polyether resins, polyurethane resins, epoxy resins, phenolic resins, polyamide resins, polyolefin resins, polyvinyl acetate resins, cellulose resins, and (meth) acrylic resins. Resin, polyimide resin, amino resin, rubber, silicon resin, and fluorine resin.

  The base layer 1 may be used with a crosslinking agent or a curing agent, if necessary. By using these, not only the friction of the base material layer 1 is reduced, but also a protective layer which has resistance to the electrolyte solution for 5 hours or more even at room temperature; A layer that allows easy determination of the necessity of maintenance of the manufacturing apparatus by having a layer to be applied; a layer that allows the heat-sealed portion to be visually identified when heat-sealed; The base material layer 1 can function as a layer or the like that eliminates a contact portion and facilitates maintenance.

  As the matting treatment, a matting agent is added to the base material layer 1 in advance to form irregularities on the surface, or a transfer method by heating or pressurizing with an embossing roll, or a mechanical method using a dry or wet blast method or a file. There is a method of roughening. Examples of the outermost layer matting agent include fine particles having a particle size of about 0.5 nm to 5 μm. The material of the matting agent is not particularly limited, and examples thereof include metals, metal oxides, inorganic substances, and organic substances. Also, the shape of the matting agent is not particularly limited, and examples thereof include a spherical shape, a fibrous shape, a plate shape, an irregular shape, and a balloon shape. As a matting agent, specifically, talc, silica, graphite, kaolin, montmorilloid, montmorillonite, synthetic mica, hydrotalcite, silica gel, zeolite, aluminum hydroxide, magnesium hydroxide, zinc oxide, magnesium oxide, oxide Aluminum, neodymium oxide, antimony oxide, titanium oxide, cerium oxide, calcium sulfate, barium sulfate, calcium carbonate, calcium silicate, lithium carbonate, calcium benzoate, calcium oxalate, magnesium stearate, alumina, carbon black, carbon nanotubes , High melting point nylon, crosslinked acryl, crosslinked styrene, crosslinked polyethylene, benzoguanamine, gold, aluminum, copper, nickel and the like. One of these matting agents may be used alone, or two or more thereof may be used in combination. Among these matting agents, preferred are silica, barium sulfate, and titanium oxide from the viewpoint of dispersion stability, cost, and the like. The matting agent may be subjected to various surface treatments such as an insulation treatment and a high dispersibility treatment on the surface noodles.

  The thin film layer of the slip agent can be formed by depositing the slip agent on the surface of the base material layer 1 by bleed-out to form a thin layer, or by laminating the slip agent on the base material layer 1. The slip agent is not particularly limited, for example, erucic acid amide, stearic acid amide, behenic acid amide, fatty acid amide such as ethylene bisoleic acid amide or ethylene bis stearic acid amide, metal soap, hydrophilic silicone, silicone grafted Acryl, silicone-grafted epoxy resin, silicone-grafted polyether, silicone-grafted polyester, block-type silicone acryl copolymer, polyglycerol-modified silicone, paraffin, and the like. One of these slip agents may be used alone, or two or more thereof may be used in combination.

  As described in detail in a third embodiment described below, the base layer 1 may have a black color from the viewpoint of effectively radiating heat from the stainless steel foil during heat sealing of the battery packaging material. . The method for making the base material layer 1 black is as described in a third embodiment described later.

  The thickness of the base material layer 1 is, for example, 3 to 75 μm, and preferably 5 to 50 μm.

[Adhesive layer 2]
In the battery packaging material of the present invention, the adhesive layer 2 is a layer provided as needed for the purpose of enhancing the adhesiveness between the base material layer 1 and the stainless steel foil 3. The base material layer 1 and the stainless steel foil 3 may be directly laminated.

  The adhesive layer 2 is formed of an adhesive resin capable of adhering the base material layer 1 and the stainless steel foil 3. The adhesive resin used to form the adhesive layer 2 may be a two-part curable adhesive resin or a one-part curable adhesive resin. Furthermore, the bonding mechanism of the bonding resin used for forming the bonding 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 resin component of the adhesive resin that can be used for forming the adhesive layer 2 include polyester resins such as polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polybutylene naphthalate, polyethylene isophthalate, polycarbonate, and copolyester. Resin; Polyether adhesive; Polyurethane adhesive; Epoxy resin; Phenolic resin; Polyamide resin such as nylon 6, nylon 66, nylon 12, copolymerized polyamide; Polyolefin, acid-modified polyolefin, metal-modified polyolefin, etc. Polyolefin resin; polyvinyl acetate resin; cellulose adhesive; (meth) acrylic resin; polyimide resin; amino resin such as urea resin and melamine resin; chloroprene rubber, nitrile rubber, and styrene Silicone resin; - down rubber such as butadiene rubber fluorinated ethylene propylene copolymer, and the like. One of these adhesive resin components may be used alone, or two or more thereof may be used in combination. The combination of two or more adhesive resin components is not particularly limited. For example, as the adhesive resin component, a mixed resin of polyamide and acid-modified polyolefin, a mixed resin of polyamide and metal-modified polyolefin, polyamide and polyester, A mixed resin of a polyester and an acid-modified polyolefin, a mixed resin of a polyester and a metal-modified polyolefin, and the like can be given. Among them, extensibility, durability under high humidity conditions, yellowing suppression effect, heat deterioration suppression effect at the time of heat sealing, and the like are excellent, and the lamination strength between the base material layer 1 and the stainless steel foil 3 is reduced. From the viewpoint of suppressing and effectively suppressing the occurrence of delamination, a polyurethane-based two-part curable adhesive resin; a polyamide, a polyester, or a blend resin of these and a modified polyolefin is preferably used.

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

  As will be described in detail in a third embodiment described later, it is desirable that heat at the time of heat sealing of the battery packaging material be effectively radiated from the stainless steel foil. Since the heat capacity of stainless steel is two to three times larger than that of aluminum, the cooling rate after heat sealing or heat treatment is low. The Young's modulus (spring constant) of stainless steel is two to three times larger than that of aluminum. Therefore, stainless steel is harder to cool than aluminum and has a large force to return to its original shape after the stress is removed. After heat-sealing the sealant layer, the resin in the sealed part is difficult to cool, and the position of the sealant layer in the sealed part tends to shift due to the force of the stainless steel foil to return to the shape before heat sealing. Is high. If the position of the sealing surface is shifted during cooling, the so-called “poly pool” shape generated at the time of sealing becomes uneven. For this reason, when the internal pressure increases due to generation of gas or temperature rise in a battery, leakage of gas or contents may occur from an uneven portion. In addition, since the sealant layer is hardened while displacing, stress tends to remain in the sealant layer. For this reason, the uniformity of the sealing strength is reduced, which may also cause leakage of gas and contents.

  From the above, when a stainless steel foil is used, it is important to cool as soon as possible after heat sealing. As a method of speeding up cooling, a method of contacting a cooling plate after heat sealing, a method of blowing air with an air cooling nozzle, or the like can be used. It is also effective to provide a layer that enhances the cooling effect outside the stainless steel foil of the battery packaging material. Among these, as a method of dissipating heat from the stainless steel foil effectively at the time of heat sealing of the battery packaging material, a relatively effective method is to blacken the outside of the battery packaging material stainless steel foil. Method. As another method, there is a method of forming a layer structure that enhances the cooling effect. For example, a method of adding fine particles such as silica, alumina, carbon, and the like, porous fine particles, fibers such as carbon fibers, and metal fillers such as aluminum, copper, and nickel to the outer layer of the stainless steel foil. No.

  As a preferable configuration for effectively radiating heat from the stainless steel foil 3 at the time of heat sealing of the battery packaging material, for example, the following embodiments may be mentioned.

(1) A mode in which a black print layer is provided on the outer surface of the base material layer 1 (the surface opposite to the stainless steel foil 3). In this embodiment, a black printing layer is provided on the outer surface of the base material layer 1 using an ink containing a black coloring material described later.
(2) An embodiment in which the base material layer 1 is colored black. In this embodiment, the base layer 1 is colored black by adding a black colorant described below to the resin constituting the base layer.
(3) A mode in which a black print layer is provided on the inner surface of the base material layer 1 (the surface of the stainless steel foil 3). In this embodiment, a black print layer is provided on the inner surface of the base material layer 1 using an ink containing a black coloring material described later.
(4) An embodiment in which the adhesive layer 2 is colored black. In this embodiment, the adhesive layer 2 is colored black by adding a black colorant described later to the resin constituting the adhesive layer 2.
(5) An embodiment in which a black colored layer is provided between the adhesive layer 2 and the stainless steel foil. In this embodiment, a black coloring layer is provided on the surface of the stainless steel foil 3 on the side of the adhesive layer 2 using a resin containing a black coloring material described later.

  Examples of black coloring materials include carbon black pigments such as carbon black, iron oxides (for example, magnetite type triiron tetroxide), composite oxides composed of copper and chromium, composites composed of copper, chromium, zinc, titanium Oxide-based black pigments such as oxides and black dyes. In order to further enhance the effect, a method of adding fine particles of silica, alumina, barium, or the like, porous fine particles, or a metal filler such as aluminum, copper, or nickel may be used. When the colored layer is formed on the outer surface, it is possible to reduce the friction as described above and to provide various functions.

  The thickness of the adhesive layer 2 is, for example, 0.5 to 50 μm, preferably 2 to 25 μm.

[Stainless steel foil 3]
In the battery packaging material of the present invention, the stainless steel foil 3 is a layer that functions as a barrier layer for preventing the invasion of water vapor, oxygen, light, and the like into the battery in addition to improving the strength of the battery packaging material. is there.

  In the present invention, the stainless steel foil 3 is preferably made of austenitic stainless steel. As a result, a battery packaging material having even higher piercing strength and excellent electrolyte solution resistance and moldability is obtained.

  Specific examples of the austenitic stainless steel constituting the stainless steel foil 3 include SUS304, SUS301, SUS316L and the like. Among these, for batteries having high piercing strength, excellent electrolyte resistance and excellent moldability. SUS304 is particularly preferred from the viewpoint of packaging materials.

  The thickness of the stainless steel foil 3 is not particularly limited. However, the thickness of the battery packaging material is further reduced, the piercing strength is high, and the battery packaging material is excellent in electrolyte resistance and moldability. Therefore, the thickness is preferably 40 μm or less, more preferably about 10 to 30 μm, and still more preferably about 15 to 25 μm.

  In addition, the stainless steel foil is particularly improved in spreadability and cold-rolled, thereby improving formability. Further, after cold rolling, heat treatment is performed and annealing is performed to improve the balance between the flow direction and the width direction, thereby improving the formability. In order to stabilize the effect of the chemical conversion treatment described below, it is important to include a surface cleaning step after the rolling treatment or after the heat treatment. Examples of the cleaning method include cleaning using an alkali or an acid, and further, alkaline electrolytic degreasing cleaning. Further, it is also possible to use ultrasonic treatment, plasma treatment and the like together. Preferably, alkali degreasing cleaning and alkali electrolytic degreasing are preferred. As a result, the wettability of the surface is improved, the chemical conversion treatment can be made uniform, and the content resistance is stabilized. As for the wettability, the contact angle with water is preferably 50 ° or less, more preferably 30 ° or less, and further preferably 15 ° or less.

[Chemical treatment tanks 3a and 3b]
In the battery packaging material of the present invention, a chemical conversion treatment layer resistant to hydrogen fluoride is formed on at least the sealant layer 4 side of the stainless steel foil 3. As a result, a wrapping material for a battery having high piercing strength, excellent electrolytic solution resistance and excellent moldability is obtained.

  In the present invention, if necessary, the surface of the stainless steel foil 3 on the side of the base material layer 1 may be used to stabilize the adhesion between the stainless steel foil and the adjacent layer and prevent melting or corrosion. May also have a chemical conversion treatment layer. In the present invention, it is more preferable that the chemical conversion treatment layers are laminated on both surfaces of the stainless steel foil. As described above, in FIGS. 1 and 2, the chemical conversion treatment layer 3a is laminated on the surface of the stainless steel foil 3 on the base material layer 1 side, and the chemical conversion treatment layer 3a is formed on the surface of the stainless steel foil 3 on the sealant layer 4 side. 3b are stacked.

  Here, the chemical conversion treatment layer is, specifically, a layer in which an acid-resistant film is formed on the surface of the stainless steel foil 3. Examples of the chemical conversion treatment for forming the chemical conversion treatment layer include chromium nitrate, chromium fluoride, chromium sulfate, chromium acetate, chromium oxalate, chromium biphosphate, chromium acetylacetate, chromium chloride, and potassium chromium sulfate. Chromic acid chromate treatment using an acid compound; phosphoric acid chromate treatment using a phosphoric acid compound such as sodium phosphate, potassium phosphate, ammonium phosphate, polyphosphoric acid; the above chromic acid compound, the above phosphoric acid compound, and Phosphoric acid chromate treatment combined with a phenolic resin is exemplified. Examples of the phenol resin include an aminated phenol polymer comprising a repeating unit represented by the following general formulas (1) to (4). 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 hydroxyl group, an alkyl group, a hydroxyalkyl group, an allyl group or a benzyl group. R ¹ and R ² are the same or different and each represents a hydroxyl group, an alkyl group, or a hydroxyalkyl group. In the general formulas (1) to (4), examples of the alkyl group represented by X, R ¹ and R ² include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, Examples thereof include a linear or branched alkyl group having 1 to 4 carbon atoms such as a tert-butyl group. Examples of the hydroxyalkyl group represented by X, R ¹ and R ² include, 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), X is preferably any one of a hydrogen atom, a hydroxyl group, and a droxyalkyl group. The number average molecular weight of the aminated phenol polymer composed of the repeating units represented by the general formulas (1) to (4) is, for example, about 500 to about 1,000,000, preferably about 1,000 to about 20,000.

  Further, as a chemical conversion treatment method for imparting corrosion resistance to the stainless steel foil 3, fine particles of metal oxides such as aluminum oxide (alumina treatment), titanium oxide, cerium oxide (cerium treatment), tin oxide, and barium sulfate are added in phosphoric acid. And a method of forming a corrosion-resistant layer on the surface of the stainless steel foil 3 by coating with a dispersion of triazine and thiol, and baking at 150 ° C. or higher. Also in these cases, the layer may be formed by being contained in a resin such as the above-mentioned phenol resin, epoxy resin, polyurethane resin, polyester resin, and fluororesin. Further, a resin layer obtained by crosslinking a cationic polymer with a crosslinking agent may be formed on the corrosion-resistant treatment layer. Here, as the cationic polymer, for example, polyethyleneimine, an ionic polymer complex comprising a polymer having polyethyleneimine and a carboxylic acid, a primary amine-grafted acrylic resin having a primary amine grafted on an acrylic main skeleton, polyallylamine or Derivatives thereof, aminophenol and the like. One of these cationic polymers may be used alone, or two or more thereof 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. One of these crosslinking agents may be used alone, or two or more thereof may be used in combination.

  One of these chemical conversion treatments may be performed alone, or two or more chemical conversion treatments may be performed in combination. Further, 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 these, the chemical conversion treatment layer is preferably formed by chromate chromate treatment or phosphoric acid chromate treatment. Further, as described in detail in a second embodiment described below, the phosphoric acid chromate treatment combining the above chromic acid compound, the above phosphoric acid compound, and a phenol resin (preferably the above aminated phenol polymer) is performed. It is particularly preferred that it is formed. The stainless steel foil has a passive film formed on the surface. Therefore, when a chemical conversion treatment is performed, it is necessary to form a mixed layer of chromium and metal after activating or removing a part of the passive film by acid treatment. In general hexavalent chromic acid treatment, it is necessary to increase the concentration of chromic acid, which imposes a heavy burden on the environment. In the phosphoric acid chromate treatment, it is possible to cope by increasing the concentration of phosphoric acid, and the environmental load can be reduced as compared with hexavalent chromic acid treatment. By the above combination, a phenol resin layer is formed on the surface of the stainless steel foil as a chemical conversion treatment layer. The formation of the resin layer increases the electric resistance of the surface. Therefore, when a battery is formed, the internal insulation is increased, and corrosion due to a short circuit or the attachment of a foreign substance, and leakage of contents due to corrosion are less likely to occur.

The amount of the acid-resistant film (chemical conversion treatment layer) formed on the surface of the stainless steel foil 3 in the chemical conversion treatment is not particularly limited. For example, a chromate treatment is performed by combining a chromate compound, a phosphoric acid compound, and an aminated phenol polymer. Is carried out, the chromate compound is about 0.5 to about 50 mg, preferably about 1.0 to about 40 mg, in terms of chromium, and the phosphorus compound is about 0, in terms of phosphorus, per m ² of the surface of the stainless steel foil 3. It is desirable that the aminated phenolic polymer be contained in a ratio of about 0.5 to about 50 mg, preferably about 1.0 to about 40 mg, and about 1 to about 200 mg, preferably about 5.0 to 150 mg.

  In the chemical conversion treatment, a solution containing a compound used for forming an acid-resistant film is applied to the surface of the stainless steel foil 3 by a bar coating method, a roll coating method, a gravure coating method, a dipping method, or the like. Is performed by heating so that the temperature is about 70 to 300 ° C. Before the stainless steel foil 3 is subjected to the chemical conversion treatment, the stainless steel foil 3 may be previously 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. By performing the degreasing treatment as described above, the passive layer on the surface of the stainless steel foil 3 can be activated or removed, and the chemical conversion treatment can be performed more efficiently.

[Sealant layer 4]
In the battery packaging material of the present invention, the sealant layer 4 corresponds to the innermost layer, and is a layer that seals the battery element by heat welding of the sealant layers 4 at the time of assembling the battery. The sealant layer 4 may be formed by a plurality of layers.

  When the sealant layer 4 does not have an adhesive layer 5 described later, the sealant layer 4 can be bonded to a chemical conversion treatment layer on the stainless steel foil 3, and the sealant layer 4 is formed of a resin that can be thermally welded to each other. In the case where the sealant layer 4 has an adhesive layer 5 described later, the sealant layer 4 can be bonded to the adhesive layer 5, and the sealant layer 4 is formed of a resin that can be thermally welded to each other. The resin forming the sealant layer 4 is not particularly limited as long as it has such characteristics, and examples thereof include an acid-modified polyolefin, a polyester resin, and a fluorine-based resin. In the case where an adhesive layer 5 described later is provided, in addition to these, the polyolefin resin and the resin forming the sealant layer 4 may be used alone or in combination of two or more.

  The acid-modified polyolefin used for forming the sealant layer 4 is a polymer modified by, for example, graft-polymerizing a polyolefin with an unsaturated carboxylic acid. Specific examples of the acid-modified 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). ), A crystalline or amorphous polypropylene such as a random copolymer of polypropylene (for example, a random copolymer of propylene and ethylene); and a terpolymer of ethylene-butene-propylene. Among these polyolefins, in terms of heat resistance, preferably, a polyolefin having at least propylene as a constituent monomer, more preferably, an ethylene-butene-propylene terpolymer and a propylene-ethylene random copolymer are used. Examples of the unsaturated carboxylic acid used for the modification include maleic acid, acrylic acid, itaconic acid, crotonic acid, maleic anhydride, itaconic anhydride and the like. Among these unsaturated carboxylic acids, preferred are maleic acid and maleic anhydride. These acid-modified polyolefins may be used alone or in a combination of two or more.

  Specific examples of the polyester resin used for forming the sealant layer 4 include a copolymer mainly composed of polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polybutylene naphthalate, polyethylene isophthalate, polycarbonate, and ethylene terephthalate. Examples include polyesters and copolymerized polyesters having butylene terephthalate as the main repeating unit. 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. One of these polyester resins may be used alone, or two or more thereof may be used in combination.

  Specific examples of the fluorine-based resin used for forming the sealant layer 4 include tetrafluoroethylene, trifluoroethylene, polyvinylidene fluoride, polyvinyl fluoride, ethylene tetrafluoroethylene, polychlorotrifluoroethylene, and ethylene chlorotrifluoroethylene. Copolymers, tetrafluoroethylene-hexafluoropropylene copolymers, fluorinated polyols and the like can be mentioned. These fluororesins may be used alone or in combination of two or more.

  In the case where the adhesive layer 5 is not provided, the sealant layer 4 may be formed only of an acid-modified polyolefin, a polyester resin, or a fluorine-based resin, and may include other resin components as required. When the sealant layer 4 contains a resin component other than the acid-modified polyolefin, polyester resin, or fluorine-based resin, the content of the acid-modified polyolefin, polyester resin, or fluorine-based resin in the sealant layer 4 is determined by the effect of the present invention. The amount is not particularly limited as long as it does not hinder the reaction.

  In the sealant layer 4, in addition to the acid-modified polyolefin, polyester resin, or fluorine-based resin, examples of resin components that can be included as needed include polyolefins.

  The polyolefin may have a non-cyclic or cyclic structure. Specific examples of the acyclic polyolefin 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 a crystalline or amorphous polypropylene such as a random copolymer of polypropylene (for example, a random copolymer of propylene and ethylene); and a terpolymer of ethylene-butene-propylene. Further, the cyclic polyolefin is a copolymer of an olefin and a cyclic monomer, and examples of the olefin which is a constituent monomer of the cyclic polyolefin include ethylene, propylene, 4-methyl-1-pentene, styrene, butadiene, and isoprene. And the like. 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, norbornadiene, and the like. These polyolefins may be used alone or in combination of two or more.

  Among these polyolefins, those having properties as an elastomer (that is, polyolefin-based elastomers), particularly propylene-based elastomers, are preferable from the viewpoint of improving the adhesive strength after heat sealing, preventing delamination after heat sealing, and the like. . Examples of the propylene-based elastomer include a polymer containing propylene and one or two or more α-olefins having 2 to 20 carbon atoms (excluding propylene) as constituent monomers. Specific examples of the α-olefins (excluding propylene) are ethylene, 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 1-octene, 1-decene, -Dodecene, 1-tetradecene, 1-hexadecene, 1-octadecene, 1-eicosene and the like. One of these ethylene-based elastomers may be used alone, or two or more thereof may be used in combination.

  When the sealant layer 4 contains a resin component other than the acid-modified polyolefin, polyester resin, or fluorine-based resin, the content of the resin component is appropriately set within a range that does not hinder the object of the present invention. For example, when a propylene-based elastomer is contained in the sealant layer 4, the content of the propylene-based elastomer in the sealant layer 4 is generally 5 to 70% by mass, preferably 10 to 60% by mass, and more preferably 20 to 50% by mass. %.

  When an adhesive layer 5 described below is provided between the stainless steel foil 3 and the sealant layer 4, as a resin forming the sealant layer 4, in addition to the acid-modified polyolefin, polyester resin, fluorine-based resin, and the like, a polyolefin And modified cyclic polyolefins. These resins may be used alone or in a combination of two or more.

  When the adhesive layer 5 is provided, the polyolefin forming the sealant layer 4 includes those exemplified above. The modified cyclic polyolefin is obtained by graft-polymerizing a cyclic polyolefin with an unsaturated carboxylic acid. The acid-modified cyclic polyolefin is a copolymer of an olefin and a cyclic monomer. Examples of such olefin include ethylene, propylene, 4-methyl-1-pentene, styrene, butadiene, isoprene and the like. Examples of the cyclic monomer include a cyclic alkene such as norbornene; specifically, a cyclic diene such as cyclopentadiene, dicyclopentadiene, cyclohexadiene, and norbornadiene. Examples of the unsaturated carboxylic acid used for the modification include maleic acid, acrylic acid, itaconic acid, crotonic acid, maleic anhydride, itaconic anhydride and the like. Among these unsaturated carboxylic acids, preferred are maleic acid and maleic anhydride. These modified cyclic polyolefins may be used alone or in a combination of two or more.

  When the adhesive layer 5 is provided, the sealant layer 4 may be formed only from an acid-modified polyolefin, a polyester resin, a fluorine-based resin, a polyolefin, or a modified cyclic polyolefin, and may contain other resin components as required. You may go out. When resin components other than these are contained in the sealant layer 4, the content of these resins in the sealant layer 4 is not particularly limited as long as the effects of the present invention are not impaired. 30 to 90% by mass, and more preferably 50 to 80% by mass. Examples of the resin component that can be contained as needed include those having the above-mentioned properties as an elastomer. Further, the content of the resin component that can be contained as necessary is appropriately set within a range not to impair the object of the present invention. For example, when a propylene-based elastomer is contained in the sealant layer 4, the content of the propylene-based elastomer in the sealant layer 4 is generally 5 to 70% by mass, preferably 10 to 60% by mass, and more preferably 20 to 50% by mass. %.

After the heat sealing of the battery packaging material of the present invention, the melting point T _m1 of the sealant layer 4 is preferably 90 to 245 ° C., and more preferably 100, from the viewpoint of effectively suppressing the displacement of the heat sealing surface. To 220 ° C. Further, from a similar viewpoint, the softening point T _s1 of the sealant layer 4 is preferably 70 to 180 ° C, more preferably 80 to 150 ° C. From the same viewpoint, the melt flow rate (MFR) at 230 ° C. of the sealant layer 4 is preferably about 1 to 25 g / 10 minutes, and more preferably 2 to 15 g / 10 minutes.

Here, the melting point T _m1 of the sealant layer 4, the melting point of the resin component constituting the sealant layer 4 JIS K6921-2: a value measured by compliant DSC method (ISO1873-2.2 95). When the sealant layer 4 is formed of a blend resin containing a plurality of resin components, its melting point T _m1 is obtained by calculating the melting point of each resin as described above, and calculating the weighted average of these by mass ratio. Can be calculated.

The softening point T _s1 of the sealant layer 4 is a value measured by a thermo-mechanical analyzer (TMA). When the sealant layer 4 is formed of a blend resin containing a plurality of resin components, its softening point T _s1 is obtained by calculating the softening point of each resin as described above, and calculating these by mass ratio. The weighted average can be calculated.

  The melt flow rate of the sealant layer 4 is a value measured by a melt flow rate measuring device according to JIS K7210.

  The thickness of the sealant layer 4 is, for example, 10 to 120 μm, preferably 10 to 80 μm, and more preferably 20 to 60 μm.

  The sealant layer 4 may be a single layer or a multilayer. In addition, the sealant layer 4 may include a slip agent or the like as needed. When the sealant layer 4 contains a slip agent, the moldability of the battery packaging material can be improved. Furthermore, in the present invention, since the sealant layer 4 contains a slip agent, not only the moldability of the battery packaging material but also the insulation properties can be improved. The detailed mechanism by which the sealant layer 4 contains a slip agent to enhance the insulating properties of the battery packaging material is not necessarily clear, but can be considered as follows, for example. That is, when the sealant layer 4 contains a slip agent, when an external force is applied to the sealant layer 4, it is considered that the molecular chains of the resin easily move in the sealant layer 4 and cracks are less likely to occur. In particular, when the sealant layer 4 is formed of a plurality of types of resins, cracks are likely to occur at the interface between these resins, but the slip agent is present at such an interface, so that at the interface, It is considered that the resin can be easily moved, so that cracks can be effectively suppressed when an external force is applied. It is considered that such a mechanism suppresses a decrease in insulation due to cracks in the sealant layer.

  The slip agent is not particularly limited, and a known slip agent can be used, and examples thereof include those exemplified for the above-described base material layer 1. One kind of slip agent may be used alone, or two or more kinds may be used in combination. The content of the slip agent in the sealant layer 4 is not particularly limited, and is preferably about 0.01 to 0.2% by mass, and more preferably 0 to 0.2% by mass, from the viewpoint of improving the moldability and insulating properties of the electronic packaging material. About 0.05 to 0.15% by mass.

[Adhesive layer 5]
In the battery packaging material of the present invention, as shown in FIG. 2, between the stainless steel foil 3 and the sealant layer 4 for the purpose of firmly bonding the stainless steel foil 3 and the sealant layer 4. An adhesive layer 5 may be further provided. The adhesive layer 5 may be formed by one layer, or may be formed by a plurality of layers.

  The bonding layer 5 is formed of a resin capable of bonding the stainless steel foil 3 and the sealant layer 4. The resin forming the adhesive layer 5 is not particularly limited as long as it is a resin capable of adhering the stainless steel foil 3 and the sealant layer 4, but preferably the above-mentioned acid-modified polyolefin, polyester resin, fluorine-based resin, polyether-based resin is used. Resin, polyurethane resin, epoxy resin, phenol resin, polyamide resin, polyolefin resin, polyvinyl acetate resin, cellulose resin, (meth) acrylic resin, polyimide resin, amino resin, rubber, silicon And the like. The resin for forming the adhesive layer 5 may be used alone or in combination of two or more.

  The adhesive layer 5 may be formed of at least one of these resins, and may include other resin components as necessary. When the adhesive layer 5 contains a resin component other than these, an acid-modified polyolefin, polyester resin, fluorine resin, polyether resin, polyurethane resin, epoxy resin, phenol resin resin, polyamide resin in the adhesive layer 5 About the content of resin, polyolefin resin, polyvinyl acetate resin, cellulose resin, (meth) acrylic resin, polyimide resin, amino resin, rubber, and silicon resin, as long as the effects of the present invention are not hindered Although not particularly limited, for example, 10 to 95% by mass, preferably 30 to 90% by mass, and more preferably 50 to 80% by mass.

  Preferably, the adhesive layer 5 further contains a curing agent. When the adhesive layer 5 contains a curing agent, the mechanical strength of the adhesive layer 5 is increased, and the insulating property of the battery packaging material can be effectively increased. One type of curing agent may be used alone, or two or more types may be used in combination.

  Curing agents include acid-modified polyolefins, polyester resins, fluorine resins, polyether resins, polyurethane resins, epoxy resins, phenolic resins, polyamide resins, polyolefin resins, polyvinyl acetate resins, and cellulose resins. There is no particular limitation as long as the resin cures a (meth) acrylic resin, a polyimide resin, an amino resin, a rubber, or a silicon resin. Examples of the curing agent include a polyfunctional isocyanate compound, a carbodiimide compound, an epoxy compound, and an oxazoline compound.

  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 compound include isophorone diisocyanate (IPDI), hexamethylene diisocyanate (HDI), tolylene diisocyanate (TDI), diphenylmethane diisocyanate (MDI), and those obtained by polymerizing or nullifying these, and mixtures thereof. Copolymers with other polymers and the like can be mentioned.

  The carbodiimide compound is not particularly limited as long as it has at least one carbodiimide group (-N = C = N-). As the carbodiimide compound, a polycarbodiimide compound having at least two carbodiimide groups is preferable. Specific examples of particularly preferred carbodiimide compounds include the following general formula (5):

[In the general formula (5), n is an integer of 2 or more. ]
A polycarbodiimide compound having a repeating unit represented by
The following general formula (6):

[In the general formula (6), n is an integer of 2 or more. ]
A polycarbodiimide compound having a repeating unit represented by
And the following general formula (7):

[In the general formula (7), n is an integer of 2 or more. ]
And a polycarbodiimide compound represented by the following formula: In the general formulas (4) to (7), n is usually an integer of 30 or less, and preferably an integer of 3 to 20.

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

  The oxazoline compound is not particularly limited as long as it has an oxazoline skeleton. Specific examples of the oxazoline compound include Epocross series manufactured by Nippon Shokubai Co., Ltd.

  From the viewpoint of increasing the mechanical strength of the adhesive layer 5, the curing agent may be composed of two or more compounds.

  In the adhesive layer 5, the content of the curing agent is determined by acid-modified polyolefin, polyester resin, fluorine resin, polyether resin, polyurethane resin, epoxy resin, phenol resin resin, polyamide resin, polyolefin resin, polyolefin resin. 0.1 to 50 parts by mass with respect to 100 parts by mass of vinyl acetate resin, cellulose resin, (meth) acrylic resin, polyimide resin, amino resin, rubber, or silicon resin. Is preferred, and more preferably in the range of 0.1 to 30 parts by mass. In the adhesive layer 5, the content of the curing agent is preferably in the range of 1 equivalent to 30 equivalents as a reactive group in the curing agent, relative to 1 equivalent of a carboxyl group in each resin such as an acid-modified polyolefin. More preferably, it is in the range of 1 equivalent to 20 equivalents. Thereby, the insulation property and durability of the battery packaging material can be further improved.

  When the adhesive layer 5 contains a curing agent, the adhesive layer 5 may be formed of a two-component curable adhesive resin or may be formed of a one-component curable adhesive resin. Further, the bonding mechanism of the adhesive is not particularly limited, and may be any of a chemical reaction type, a solvent volatilization type, a hot-melt type, a hot pressure type, and an electron beam curing type such as UV and EB.

The melting point T _m2 of the adhesive layer 5, preferably ninety to two hundred forty-five ° C., and more preferably include 100 to 230 ° C.. From the same viewpoint, the softening point T _s2 of the adhesive layer 5, preferably 70 to 180 ° C., more preferably include 80 to 150 ° C..

The method of calculating the melting point _Tm2 and the softening point _Ts2 of the adhesive layer 5 is the same as that of the sealant layer 4.

  The thickness of the adhesive layer 5 is not particularly limited, but is preferably 0.01 μm or more, and more preferably 0.05 to 20 μm. If the thickness of the adhesive layer 5 is less than 0.01 μm, it may be difficult to stably bond the stainless steel foil 3 and the sealant layer 4.

  In the battery packaging material of the present invention, the total thickness of the laminate including each of the above layers is not particularly limited, but the thickness of the battery packaging material is reduced, high piercing strength, excellent electrolytic solution resistance and From the viewpoint of suitably exhibiting moldability and the like, the thickness is preferably 110 µm or less, more preferably about 42 to 85 µm, and further preferably about 45 to 70 µm.

  In the battery packaging material of the present invention, the piercing strength of the laminate measured by a measuring method in accordance with JIS Z 1707 1997 is preferably 18 N or more, more preferably 20 N or more.

  Further, from the viewpoint of reducing the thickness of the battery packaging material and suitably exhibiting high piercing strength, excellent electrolytic solution resistance and moldability, the total thickness of the laminate is set to T (μm), and the stainless steel foil is used. When the piercing strength of the laminated body measured by a measuring method based on the thickness of TS (μm) and JIS Z 1707 1997 is F (N), F / T is 0.3 (N / μm). ) The F / TS is preferably 0.7 (N / μm) or more.

3. Production method of battery packaging material The production method of 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 is obtained, but, for example, the following method is exemplified. .

  First, a laminate (hereinafter, sometimes referred to as “laminate A”) in which the base material layer 1, the adhesive layer 2, and the stainless steel foil 3 are laminated in order as necessary is formed. Specifically, the laminate A having the adhesive layer 2 is formed by thermal laminating, sand laminating, and dry laminating the substrate layer 1, the adhesive layer 2, and the stainless steel foil 3 whose surface has been subjected to chemical conversion treatment. It is performed by laminating by a method, a melt extrusion method, a coextrusion method or a combination thereof. In the formation of the laminate A, the stability of the adhesion between the base material layer 1 and the stainless steel foil 3 by the adhesive layer 2 is improved by performing aging treatment, water treatment, heat treatment, electron beam treatment, ultraviolet treatment, and the like. Can increase. As a method of forming the laminate A by directly laminating the base material layer 1 on the stainless steel foil 3, the lamination is performed by a thermal lamination method, a solution coating method, a melt extrusion method, a co-extrusion method or a combination thereof. There is a method to make it. At this time, by performing aging treatment, water treatment, heat treatment, electron beam treatment, ultraviolet treatment, and the like, the stability of adhesion between the base material layer 1 and the stainless steel foil 3 can be increased.

  In the formation of the laminate A by the dry lamination method, for example, a resin constituting the adhesive layer 2 is dissolved or dispersed in water or an organic solvent, and the solution or dispersion is coated on the base material layer 1, Alternatively, the drying can be performed by drying the organic solvent to form the adhesive layer 2 on the base material layer 1 and then heating and pressing the stainless steel foil 3.

  The formation of the laminate A by the thermal laminating method is performed, for example, by preparing a multilayer film in which the base layer 1 and the adhesive layer 2 are laminated in advance, and bonding the base layer 1 and the stainless steel foil 3 to the adhesive layer 2 with a heating roll. And by thermocompression bonding. The laminate A is formed by a thermal lamination method by preparing a multilayer film in which a stainless steel foil 3 and an adhesive layer 2 are laminated in advance, and laminating the base material layer 1 on the heated stainless steel foil 3 and the adhesive layer 2. Alternatively, thermocompression bonding may be performed while holding the adhesive layer 2 between the base material layer 1 and the stainless steel foil 3.

  In the thermal lamination method, a multilayer film in which the base layer 1 and the adhesive layer 2 prepared in advance are laminated is formed by melt-extrusion or solution coating of the adhesive forming the adhesive layer 2 on the resin film forming the base layer 1. After laminating and drying by (liquid coating), it is formed by baking at a temperature equal to or higher than the melting point of the adhesive constituting the adhesive layer 2. By performing the baking, the bonding strength between the stainless steel foil 3 and the bonding layer 2 is improved. Similarly, for a multilayer film in which the stainless steel foil 3 and the adhesive layer 2 prepared in advance in the thermal laminating method are laminated, the adhesive constituting the adhesive layer 2 is melt-extruded on the metal foil constituting the stainless steel foil 3. Alternatively, it is formed by baking at a temperature equal to or higher than the melting point of the adhesive constituting the adhesive layer 2 after laminating and drying by solution coating.

  The laminate A is formed by the sand lamination method by, for example, melting and extruding the adhesive constituting the adhesive layer 2 onto the upper surface of the stainless steel foil 3 and attaching the resin film constituting the base layer 1 to the stainless steel foil. It can be done by matching. At this time, it is desirable that after the resin films are pasted and temporarily bonded, heating is performed again to perform the main bonding. In the sand lamination method, the adhesive layer 2 may be multilayered with different resin types. In this case, a multilayer film in which the base layer 1 and the adhesive layer 2 are laminated is prepared in advance, and the adhesive constituting the adhesive layer 2 is melt-extruded on the upper surface of the stainless steel foil 3 to form a multilayer resin film and a thermal laminating method. May be laminated. Thereby, the adhesive layer 2 constituting the multilayer film and the adhesive layer 2 laminated on the upper surface of the stainless steel foil 3 are adhered to form the two adhesive layers 2. When the adhesive layer 2 is multilayered with different resin types, a multilayer film in which the stainless steel foil 3 and the adhesive layer 2 are laminated is prepared in advance, and the adhesive constituting the adhesive layer 2 is provided on the base material layer 1. It may be melt-extruded and laminated with the adhesive layer 2 on the stainless steel foil 3. As a result, an adhesive layer 2 composed of two different adhesives is formed between the multilayer resin fill and the base material layer 1.

  Next, the sealant layer 4 is laminated on the stainless steel foil 3 of the laminate A. Lamination of the sealant layer 4 on the stainless steel foil 3 of the laminate A can be performed by a coextrusion method, a thermal lamination method, a sand lamination method, a coating method, a combination thereof, or the like. For example, when the adhesive layer 5 is not provided, the sealant layer 4 can be formed on the stainless steel foil 3 by a melt extrusion method, a thermal lamination method, a coating method, or the like. When the adhesive layer 5 is provided, the sealant layer 4 can be formed by a similar method after forming the adhesive layer 5 on the stainless steel foil 3 by a melt extrusion method, a thermal laminating method, a coating method, or the like. Further, a co-extrusion method in which the adhesive layer 5 and the sealant layer 4 are simultaneously melt-extruded on the stainless steel foil 3 may be performed. Further, it is also possible to perform a sand lamination method in which the adhesive layer 5 is melt-extruded onto the stainless steel foil 3 and the film-like sealant layer 4 is attached. When the sealant layer 4 is formed by two layers, for example, after extruding one layer of the adhesive layer 5 and the sealant layer 4 on the stainless steel foil 3, another one layer of the sealant layer 4 is subjected to thermal lamination. There is a method of attaching. In addition, a method of extruding one layer of the adhesive layer 5 and the sealant layer 4 on the stainless steel foil 3 and bonding another layer of the film-like sealant layer 4 to the stainless steel foil 3 may be used. When the number of the sealant layer 4 is three or more, the sealant layer 4 can be further formed by a melt extrusion method, a thermal laminating method, a coating method, or the like.

  As described above, a laminate composed of the base material layer 1 / adhesive layer 2 formed as needed / chemically treated stainless steel foil 3 / adhesive layer 5 formed as needed / sealant layer 4 It is formed. In order to strengthen the adhesiveness of the adhesive layer 2, it may be further subjected to heat treatment such as hot roll contact, hot air, near or far infrared ray irradiation, dielectric heating, and heat resistance heating. The conditions of such a heat treatment include, for example, 150 to 250 ° C. for 1 to 10 hours.

  Moreover, in the battery packaging material of the present invention, each layer constituting the laminate improves or stabilizes the film forming property, lamination processing, suitability for secondary processing of the final product (pouching, embossing), etc. as necessary. Surface treatment such as corona treatment, blast treatment, oxidation treatment, and ozone treatment.

When packaging a battery element using the battery packaging material of the present invention, the same or different two packaging materials for batteries may be used. Specific examples of the laminated structure of each battery packaging material in the case of packaging a battery element using two different battery packaging materials include the following, for example.
One battery packaging material: base material layer 1 (nylon layer) / adhesive layer 2 (two-component curable polyester resin layer) / stainless steel foil 3 / adhesive layer 5 (acid-modified polypropylene layer) / sealant layer 4 (polypropylene layer) )
The other battery packaging material: base material layer 1 (acrylic-urethane coat layer) / stainless steel foil 3 / adhesive layer 5 (fluororesin layer) / sealant layer 4 (polypropylene)

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

  Specifically, 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 using a battery packaging material is formed by forming a flange portion (a region where the sealant layers are in contact with each other) on the periphery of the element so as to form a cover, and heat-sealing the sealant layers 4 of the flange portion to form a seal. Is provided. When a battery element is accommodated using the battery packaging material of the present invention, it is used such that the sealant layer 4 of the battery packaging material of the present invention is on the inside (the surface in contact with the battery element).

  As described above, two battery packaging materials of the present invention are prepared, and the sealant layer 4 is heat-welded in a state where the sealant layers 4 are opposed to each other. May be accommodated. In addition, by preparing the battery packaging material of the present invention and the above-mentioned sheet-like laminate, and thermally sealing the sealant layer 4 in a state where the sealant layers 4 are opposed to each other, the electron The element may be accommodated.

  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 battery, a nickel hydrogen battery, and a nickel cadmium battery. And nickel / iron storage batteries, nickel / zinc storage batteries, silver oxide / zinc storage batteries, metal-air batteries, polyvalent cation batteries, capacitors, capacitors and the like. Among these secondary batteries, suitable applications of the battery packaging material of the present invention include lithium ion batteries and lithium ion polymer batteries.

(Second embodiment)
In the second embodiment of the present invention, in the first embodiment, the chemical conversion treatment layer formed on the surface of the stainless steel foil 3 is further formed by a phosphoric acid chromate treatment using a resin. It is characterized by: Hereinafter, the second embodiment will be described in detail. In the second embodiment, other configurations not described in detail below are the same as those in the first embodiment.

  In the second embodiment, a chemical conversion treatment layer formed by phosphoric acid chromate treatment using a resin is laminated on at least one surface of the stainless steel foil 3, so that the piercing strength and the electrolytic solution are prevented. Excellent in moldability and moldability. In particular, when the stainless steel foil 3 is formed of austenitic or SUS304, the stainless steel foil 3 has a high affinity with a chemical conversion treatment layer formed by phosphoric acid chromate treatment using a resin, and has excellent electrolytic solution resistance. Is obtained. Further, the formation of the resin layer increases the electric resistance. Therefore, when a battery is formed, the internal insulation is increased, and corrosion due to short-circuiting or adhesion of foreign matter, and leakage of contents due to corrosion are less likely to occur.

  In the second embodiment, the resin used for the phosphoric acid chromate treatment is not particularly limited, but is preferably a phenol resin. The phenol resin is preferably an aminated phenol polymer, and the details of the aminated phenol polymer are as described in the first embodiment.

  In the second embodiment, at least one surface of the stainless steel foil 3 is subjected to a phosphoric acid chromate treatment in which a chromic acid compound, a phosphoric acid compound, and a phenol resin (preferably, the above aminated phenol polymer) are combined. It is particularly preferable to have the formed chemical conversion treatment layer. In particular, by having a chemical conversion treatment layer formed by the phosphoric acid chromate treatment on the surface of the austenitic stainless steel, and also the stainless steel foil 3 formed of SUS304, high piercing strength, excellent moldability, Excellent electrolyte resistance is obtained. Further, the formation of the resin layer increases the electric resistance. Therefore, when a battery is formed, the internal insulation is increased, and corrosion due to a short circuit or the attachment of a foreign substance, and leakage of contents due to corrosion are less likely to occur.

  In the second embodiment, the thickness of the stainless steel foil 3 can be set to 40 μm or less, and more preferably 10 to 30 μm or less, because it has excellent piercing strength, electrolytic solution resistance, and moldability. When the stainless steel foil 3 is thick, the specific gravity of stainless steel is about three times that of aluminum, so that the weight of the battery packaging material increases, and the amount of power generation per unit weight is lower than that of a similar battery using aluminum. .

(Third embodiment)
A third embodiment of the present invention is characterized in that, in the first embodiment, at least one of the layers located on the base material layer 1 side of the stainless steel foil 3 is black. In the third embodiment, by providing such a configuration, the heat dissipation of the stainless steel foil 3 is improved, and the stainless steel foil 3 heated during heat sealing is maintained at a high temperature for a long period of time. Therefore, it is possible to effectively suppress the occurrence of displacement due to movement of the heat sealing surface after heat sealing.

  Since stainless steel has a larger heat capacity per unit volume than aluminum, the temperature is less likely to fluctuate. Further, stainless steel has a higher Young's modulus (spring constant) than aluminum, and after releasing the pressure at the time of heat sealing, it rebounds and tends to return to a normal state. For this reason, when a stainless steel foil is used, the stainless steel foil heated at the time of heat sealing is maintained at a high temperature for a long period of time, compared with the case where a conventionally used aluminum foil is used for the barrier layer. In addition, a force that tends to peel off in that state is likely to work. Therefore, when a stainless steel foil is used, there is a problem that the sealant layer 4 is hardly cooled after the heat sealing, a state of high fluidity may be maintained, and the heat sealing surface is moved to easily cause a positional shift. . If the position of the sealing surface is shifted during cooling, the so-called “poly pool” shape generated at the time of sealing becomes uneven. For this reason, when the internal pressure increases due to generation of gas or temperature rise in a battery, leakage of gas or contents may occur from an uneven portion. In addition, since the sealant layer is hardened while displacing, stress tends to remain in the sealant layer. For this reason, the uniformity of the sealing strength is reduced, which may also cause leakage of gas and contents.

  On the other hand, in the third embodiment, since at least one of the layers located on the base material layer 1 side of the stainless steel foil 3 is black, the heat dissipation is excellent, and the stainless steel foil is cooled. Easy to be. For this reason, it is difficult to maintain the high fluidity state of the sealant layer 4, and the positional deviation of the heat sealing surface after the heat sealing is effectively suppressed.

  In the third embodiment, at least one of the layers located on the base material layer 1 side of the stainless steel foil 3 only needs to be black.

  As a preferable configuration for effectively radiating heat from the stainless steel foil 3 at the time of heat sealing of the battery packaging material, for example, the following embodiments may be mentioned.

(1) A mode in which a black print layer is provided on the outer surface of the base material layer 1 (the surface opposite to the stainless steel foil 3). In this embodiment, a black printing layer is provided on the outer surface of the base material layer 1 using an ink containing a black coloring material described later.
(2) An embodiment in which the base material layer 1 is colored black. In this embodiment, the base layer 1 is colored black by adding a black colorant described below to the resin constituting the base layer.
(3) A mode in which a black print layer is provided on the inner surface of the base material layer 1 (the surface of the stainless steel foil 3). In this embodiment, a black print layer is provided on the inner surface of the base material layer 1 using an ink containing a black coloring material described later.
(4) An embodiment in which the adhesive layer 2 is colored black. In this embodiment, the adhesive layer 2 is colored black by adding a black colorant described later to the resin constituting the adhesive layer 2.
(5) An embodiment in which a black colored layer is provided between the adhesive layer 2 and the stainless steel foil. In this embodiment, a black coloring layer is provided on the surface of the stainless steel foil 3 on the side of the adhesive layer 2 using a resin containing a black coloring material described later.

  Among these, the above-described embodiments (3), (4), and (5) are particularly preferable from the viewpoint of suppressing generation of foreign matter.

  The method for blacking the layers such as the base layer 1, the adhesive layer 2, the printing layer, and the coloring layer is not particularly limited, and for example, a black coloring material or the like may be blended with the resin or ink constituting each layer. The black colorant is not particularly limited, but is preferably a carbon black pigment such as carbon black, iron oxide (for example, magnetite type triiron tetroxide), a composite oxide composed of copper and chromium, copper, and chromium. , Zinc-based composites, oxide-based black pigments such as titanium-based oxides, and black dyes. The particle size of the black pigment is not particularly limited, but is preferably about 1 nm to 20 μm. The particle diameter of the black pigment means a value measured by a laser diffraction scattering method. Further, in order to further enhance the effect, fine particles such as silica, alumina and barium, porous fine particles, and a metal filler such as aluminum, copper and nickel may be added. Further, when the print layer is formed on the outer surface as in the mode (1), it is possible to reduce the friction as described above and to provide various functions.

  The resins used in the embodiments (1), (3) and (5) include polyester resins, polyether resins, polyurethane resins, epoxy resins, phenol resin resins, polyamide resins, polyolefin resins, Examples include polyvinyl acetate resin, cellulose resin, (meth) acrylic resin, polyimide resin, amino resin, rubber, silicon resin, and fluorine resin. It is desirable to use a cross-linking agent and a curing agent together as necessary.

  The mixing ratio of the black coloring material in each layer is not particularly limited as long as the layer becomes black, and for example, about 5 to 50% by mass, more preferably about 8 to 20% by mass.

  By using the third embodiment and a fourth embodiment described later together, it is possible to more effectively suppress the occurrence of displacement due to movement of the heat sealing surface of the sealant layer 4 after heat sealing. Can be.

(Fourth embodiment)
The fourth embodiment of the present invention is characterized in that the melt flow rate (MFR) at 230 ° C. of the sealant layer 4 is 15 g / 10 minutes or less in the first embodiment. The fourth embodiment has such a configuration, so that the fluidity of the sealant layer 4 is low, and even when the stainless steel foil heated at the time of heat sealing is maintained at a high temperature for a long period of time. The displacement of the heat seal surface of the sealant layer 4 due to the movement thereof is effectively suppressed.

  The MFR of the sealant layer 4 at 230 ° C. is preferably about 1 to 15 g / 10 minutes, more preferably 2 to 15 g / 10 minutes.

  As a method of setting the MFR of the sealant layer 4 to the above value, the composition of the resin constituting the sealant layer 4 may be appropriately set. In particular, when polypropylene is used, the lower the MFR, the less the sealant moves in the heated state after heat sealing. In addition, the formation of a so-called “poly pool” during heat sealing is also stabilized. Therefore, the sealing performance in heat sealing is stabilized. When the MFR is high, the formation of the poly pool is small, and when the seal position shifts, the formation of the poly pool is small, so that the poly pool tends to be uneven. The generation of gas inside the battery may cause the bag to break from an uneven portion when the internal pressure increases due to a rise in temperature.

  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.

Production of Battery Packaging Material In the following Examples 1 to 17 and Comparative Examples 1 and 2, battery packaging materials were produced, respectively. The thickness, material, physical properties (melting point, MFR) and the like of each layer are as shown in Table 1. The details of the formation of the chemical conversion treatment layer performed in the following Examples and Comparative Examples are as follows.

(Phosphoric acid chromate treatment)
Applying a treatment solution comprising a phenolic resin, a chromium fluoride compound, and phosphoric acid to the surface of a stainless steel foil or an aluminum foil by a roll coating method so that the application amount of chromium is 10 mg / m ² (dry weight); This was performed by baking for 20 seconds under the condition that the film temperature was 180 ° C. or higher.

(Chromate treatment)
A treatment solution composed of chromic acid is applied to the surface of a stainless steel foil or an aluminum foil by a roll coating method so that the amount of chromium applied is 10 mg / m ² (dry weight), and the condition that the coating temperature is 180 ° C. or higher. For 20 seconds.

(Alumina treatment)
A treatment solution consisting of a phenolic resin, alumina and phosphoric acid is applied to the surface of a stainless steel foil or an aluminum foil by a roll coating method so that the applied amount is 1 μ (dry thickness), and the condition that the coating temperature is 200 ° C. or higher. For 20 seconds.

(Cerium treatment)
A treatment liquid mainly composed of cerium oxide, phosphoric acid, and an acrylic resin is applied to the surface of a stainless steel foil or an aluminum foil by a roll coating method so that the applied amount is 1 μ (dry thickness), and the coating temperature is 200 ° C. Baking was performed for 20 seconds under the conditions described above.

<Example 1>
Polyethylene terephthalate (PET) as a base material layer is coated with an adhesive consisting of a polyester resin as a main component and a TDI isocyanate as a curing agent, dried, and laminated with an austenitic stainless steel foil (SUS304) that has been subjected to phosphoric acid chromate treatment on both sides. Then, an aging treatment was performed at 80 ° C. for 3 days. Then, on the other side, an adhesive layer (acid-modified PP) in which acid-modified propylene, an ethylene copolymer and low-density polyethylene were blended, and a random polypropylene were laminated by a co-extrusion method. To further increase the adhesive strength, the substrate was heated at 180 ° C., which is higher than the softening point of the acid-modified PP, for 30 seconds.

<Example 2>
Polyethylene terephthalate (PET) as a base material layer is coated with an adhesive composed of a polyester resin as a main component and a TDI isocyanate as a curing agent, and after drying, chromate-treated a stainless steel foil (SUS304) having one surface subjected to chromate treatment. After being bonded to the uncoated surface, an aging treatment was performed at 60 ° C. for 5 days. Then, on the other side, an adhesive layer (acid-modified PP) in which acid-modified propylene, an ethylene copolymer and low-density polyethylene were blended, and a random polypropylene were laminated by a co-extrusion method. In order to further increase the adhesive strength, the substrate was heated at 180 ° C., which is higher than the softening point of the acid-modified PP, for 30 seconds.

<Example 3>
Polyethylene terephthalate (PET) as a base material layer was coated with an adhesive composed of a polyether resin as a main component and an MDI-based isocyanate as a curing agent, dried, and bonded to a stainless steel foil (SUS304) having both surfaces treated with alumina. Thereafter, aging treatment was performed at 40 ° C. for 7 days. Then, on the other side, an adhesive layer made of a fluororesin and an IPDI-based isocyanate is applied by solution coating, dried, and a sealant film made of a block PP / random PP is stuck to the block PP surface, and then at 50 ° C. The aging treatment was performed for 5 days.

<Example 4>
Polyethylene terephthalate (PET) as a base material layer is coated with an adhesive composed of a polyester-polyether resin as a main component and an HDI-based isocyanate as a curing agent, dried, and then pasted to a cerium-treated stainless steel foil (SUS316) on one side. After the combination, an aging treatment was performed at 40 ° C. for 7 days. Thereafter, a multilayer film composed of acid-modified polypropylene (acid-modified PP) and random polypropylene (random PP) was laminated by a thermal lamination method such that the acid-modified PP was on the stainless steel foil side.

<Example 5>
Stainless steel foil (SUS304) with polybutylene terephthalate (PBT) as a base material layer coated with an adhesive consisting of a polyester resin as a base material and an adduct isocyanate of TDI as a hardener, dried, and then subjected to phosphoric acid chromate treatment on both sides (SUS304) After that, an aging treatment was performed at 60 ° C. for 7 days. Thereafter, a multilayer film composed of acid-modified PP and random PP was laminated by a thermal lamination method so that the acid-modified PP was on the stainless steel foil side.

<Example 6>
Polyethylene naphthalate (PEN) as a base material layer is coated with an adhesive composed of a polyester resin as a base material and an adduct isocyanate of TDI as a curing agent, dried, and then subjected to phosphoric acid chromate-treated stainless steel foil (SUS304) After being bonded to the surface on which the chemical conversion treatment layer was not formed, aging treatment was performed at 60 ° C. for 7 days. Thereafter, the acid-modified PP and the block PP were laminated on the other side by a co-extrusion method.

<Example 7>
Nylon as a base material layer is coated with an adhesive composed of a polyester resin as a main agent and an adduct isocyanate of TDI as a curing agent, dried, and then bonded to a stainless steel foil (SUS304) having both surfaces subjected to phosphoric acid chromate treatment. Aging treatment at 60 ° C. for 7 days. Thereafter, an adhesive layer made of acid-modified PP and oxazoline was applied on the other side by solution coating, dried, and a sealant film made of random PP was stuck thereon, followed by aging treatment at 60 ° C. for 5 days.

<Example 8>
A PET / nylon co-extruded film as a base material layer is coated with an adhesive composed of a polyester resin as a main ingredient and an MDI-based isocyanate as a curing agent, dried, and then subjected to phosphoric acid chromate-treated stainless steel foil (SUS304). After bonding with the surface on which the chemical conversion treatment layer was not formed, aging treatment was performed at 60 ° C. for 7 days. Thereafter, an adhesive layer composed of an acid-modified PP, an epoxy resin, and an acid catalyst is applied on the other side by solution coating, dried, and a random / block / random sealant film is attached thereto, followed by aging at 80 ° C. for 5 days. Processing was performed.

<Example 9>
A base resin composed of polyester-polyurethane and acrylic and an MDI-based curing agent as a base material layer are laminated on a stainless steel foil (SUS304) on both sides by phosphoric acid chromate treatment by solution coating, dried, and then aged at 80 ° C. for 5 days. Thus, a laminate of the base material layer / chemical conversion treatment layer / stainless steel foil / chemical conversion treatment layer was formed. After that, an adhesive layer made of an acid-modified PP, an epoxy resin, and an acid catalyst is applied on the surface of the chemical conversion treatment layer by solution coating, dried, and a sealant film made of random PP / block PP / random PP is attached. An aging treatment was performed at 80 ° C. for 5 days.

<Example 10>
Polyethylene terephthalate (PET) as a base material layer is coated with 10% black carbon added to an adhesive consisting of a polyester resin as a base material and a TDI isocyanate as a curing agent. Foil (SUS304) was laminated and subjected to aging treatment at 80 ° C. for 3 days. Thereafter, on the other side, an adhesive layer (acid-modified PP) in which propylene, an ethylene copolymer, and a low-density polyethylene were blended by acid co-extrusion and random polypropylene (random PP) were laminated. To further increase the adhesive strength, the substrate was heated at 180 ° C., which is higher than the softening point of the acid-modified PP, for 30 seconds.

<Example 11>
A polycarbonate (PC) kneaded with 5% of carbon as a base material layer is coated with an adhesive composed of a polyester resin as a main component and a TDI isocyanate as a curing agent, dried, and then subjected to a double-sided phosphoric acid chromate-treated stainless steel foil ( SUS304) was laminated and subjected to an aging treatment at 80 ° C. for 3 days. Then, on the other side, an adhesive layer (acid-modified PP + filler) in which 5% of layered montmorillonite is added to acid-modified propylene-ethylene copolymer and low-density polyethylene is sandwiched by a random polypropylene film of a sealant layer. Then, the acid-modified PP + filler was extruded and laminated on the surface of the stainless steel foil.

<Example 12>
Polyethylene terephthalate (PET) as a base material layer is coated with a composition obtained by adding a polyester resin and an acrylic resin as main components, an MDI-based isocyanate as a curing agent, and black carbon (10%) to form a print layer. After drying, aging was performed at 40 ° C. for 3 days. Further, the printed layer was laminated with a stainless steel foil (SUS304) which had been subjected to phosphoric acid chromate treatment on both sides, and was subjected to an aging treatment at 80 ° C. for 3 days. Thereafter, the other surface of the stainless steel foil was laminated by thermal lamination such that the acid-modified PP surface of the multilayer film composed of the acid-modified PP and the random PP was on the stainless side. Further, an outer layer coating agent obtained by adding a curing agent of MDI isocyanate and 5% silica and 2,000 ppm of erucic acid amide to a main agent composed of a polyurethane resin and an acrylic resin is coated on the outer surface of the PET of the base material layer to form a 3 μm mat layer. Formed and aged at 45 ° C. for 5 days.

<Example 13>
Nylon as a base material layer is coated with a composition obtained by adding 10% of black carbon to an adhesive composed of a polyester resin as a main agent and a TDI-based isocyanate as a curing agent, and then dried, and then subjected to double-sided phosphoric acid chromate treatment. Steel foil (SUS304) was laminated and subjected to aging treatment at 80 ° C. for 3 days. Thereafter, an adhesive layer composed of an acid-modified PP, an epoxy resin, and an acid catalyst was applied on another surface of the stainless steel foil by solution coating, dried, and a sealant film composed of random PP / block PP / random PP was attached. Thereafter, an aging treatment was performed at 80 ° C. for 5 days. Further, an outer layer coating agent obtained by adding a hardening agent of HDI-based isocyanate and 5% of silica and 2,000 ppm of erucic acid amide to a main component made of a polyurethane resin is coated on the outer surface of the nylon to form a 3 μm mat layer. For 5 days.

<Example 14>
One layer of polyethylene terephthalate (PET) as a base material layer, an outer layer coating agent in which a curing agent of MDI isocyanate and 12% of black carbon, 3% of silica, and 1000 ppm of erucic acid amide are added in advance to a base material composed of polyurethane and an acrylic resin. To form an outer layer of 5 μm. Next, on the surface opposite to the outer layer of the base material, an adhesive comprising a polyester resin as a main component and a TDI-based isocyanate as a curing agent was coated, and after drying, a stainless steel foil (SUS301) subjected to a double-sided phosphoric acid chromate treatment. They were laminated and subjected to an aging treatment at 80 ° C. for 3 days. Then, on the other side, the adhesive layer (acid-modified PP) in which the acid-modified propylene-ethylene copolymer and low-density polyethylene are blended is sandwiched by a random polypropylene (random PP) film of the sealant layer so that the surface of the stainless steel foil is sandwiched. The acid-modified PP was extruded and laminated.

<Example 15>
As a base material layer, a stainless steel foil (SUS304) in which a solution containing a main resin composed of polyester-polyurethane and acrylic, an MDI-based curing agent, 20% of black carbon, 5% of silica and 2000 ppm of stearic acid amide was subjected to phosphoric acid chromate treatment on both surfaces was used. ) Was laminated by solution coating, dried and then aged at 80 ° C. for 5 days to form a laminate of a base material layer / chemical conversion layer / stainless steel foil / chemical conversion layer. Then, after applying an adhesive layer composed of an acid-modified PP, an epoxy resin, and an acid catalyst on the surface of the chemical conversion treatment layer by solution coating, drying, and bonding a sealant film composed of random PP / block PP / random PP, An aging treatment was performed at 80 ° C. for 5 days.

<Example 16>
A polyethylene steel terephthalate (PET) as a base material layer is coated with an adhesive composed of a polyester resin as a main component and a TDI-based isocyanate as a curing agent, and after drying, a double-sided phosphoric acid chromated stainless steel foil (SUS304) is laminated. The aging treatment was performed at 80 ° C. for 3 days. Then, on the other surface, a random polypropylene (random PP) and an adhesive layer (acid-modified PP) in which propylene, an ethylene copolymer, and a low-density polyethylene were blended by an acid extrusion method were laminated. To further increase the adhesive strength, the substrate was heated at 180 ° C., which is higher than the softening point of the acid-modified PP, for 30 seconds.

<Example 17>
Polyethylene terephthalate (PET) as a base material layer is coated with an adhesive composed of a polyester resin as a main component and a TDI isocyanate as a curing agent, dried, and then subjected to a double-sided phosphoric acid chromate-treated ferritic stainless steel foil (SUS YSU190). They were laminated and subjected to an aging treatment at 80 ° C. for 3 days. Then, on the other surface, a random polypropylene (random PP) and an adhesive layer (acid-modified PP) in which propylene, an ethylene copolymer, and a low-density polyethylene were blended by an acid extrusion method were laminated. In order to further increase the adhesive strength, the substrate was heated at 180 ° C., which is higher than the softening point of the acid-modified PP, for 30 seconds.

<Comparative Example 1>
A polyethylene terephthalate (PET) as a base material layer is coated with an adhesive composed of a polyester resin as a main component and a TDI-based isocyanate as a curing agent. For 3 days. Then, on the other surface, a random polypropylene (random PP) and an adhesive layer (acid-modified PP) in which propylene, an ethylene copolymer, and a low-density polyethylene were blended by an acid extrusion method were laminated. In order to further increase the adhesive strength, the substrate was heated at 180 ° C., which is higher than the softening point of the acid-modified PP, for 30 seconds.

<Comparative Example 2>
Polyethylene terephthalate (PET) as a base material layer is coated with an adhesive composed of a polyester resin as a main component and a TDI isocyanate as a curing agent, dried, and laminated with a stainless steel foil (SUS304) that has not been subjected to a chemical conversion treatment. The aging treatment was performed at 80 ° C. for 3 days. Thereafter, on the other side, an adhesive layer (acid-modified PP) in which propylene, an ethylene copolymer, and a low-density polyethylene were blended by acid co-extrusion and random polypropylene (random PP) were laminated. To further increase the adhesive strength, the substrate was heated at 180 ° C., which is higher than the softening point of the acid-modified PP, for 30 seconds.

(Stab test)
Each of the battery packaging materials obtained in the above Examples and Comparative Examples was cut to prepare strips of 120 mm x 80 mm, which were used as test samples. Using a piercing tester (MX2-500N manufactured by Imada), the piercing strength of each test sample was measured by a method based on JIS Z 1707 1997. Table 2 shows the results.

(Formability evaluation)
Each of the battery packaging materials obtained in the above Examples and Comparative Examples was cut to prepare strips of 120 mm x 80 mm, which were used as test samples. Using a molding die of 30 × 50 mm, cold molding was performed at a pressing pressure of 0.4 MPa and a molding depth of 0.1 mm unit. Each depth was molded at N = 30, and the presence or absence of pinholes and cracks in the metal layer in the molded battery packaging material was confirmed. The depth at which no pinholes and cracks occurred was defined as the molding limit value. Further, the molding limit was divided by the total thickness (μm), and the converted value of the molding limit with respect to the total thickness was compared. Table 2 shows the results.

(Evaluation of electrolyte resistance)
After cutting each of the battery packaging materials obtained in the above Examples and Comparative Examples into 80 mm x 150 mm, a forming die (female type) having a diameter of 35 mm x 50 mm and a forming die (male type) corresponding thereto. Then, cold forming was performed at 0.4 MPa to a depth of 1.0 mm, and a concave portion was formed at the center thereof. The concave portion was filled with 1 g of the above electrolyte solution (ethylene carbonate, diethyl carbonate, dimethyl carbonate (1: 1: 1) made into 1M LiPF ₆ ), and another sheet of the packaging material for a battery was sealed with the sealant layers. The recess was overlapped so as to face the periphery, and the periphery was heat-sealed. The conditions of the heat sealing were 190 ° C. and a surface pressure of 1.0 MPa for 3 seconds. This was stored at 85 ° C. for one day, opened, and visually checked for delamination between the barrier layer (stainless steel foil or aluminum foil) and the sealant layer. Table 2 shows the results.

(Insulation evaluation)
Each of the battery packaging materials obtained in the above Examples and Comparative Examples was cut, and strips having a width of 25 mm and a length of 60 were prepared and used as test samples. On the sealant surface side of the strip, an aluminum plate having a width of 40 μm and a thickness of 100 μm, in which a stainless steel wire having a diameter of 25 μm was disposed at the center, was disposed. At this time, the center of the strip was aligned with the center of the aluminum. Furthermore, the tip of the wire was clamped to the minus side, and the strip of stainless steel foil was clamped to the plus side, and set on a tester. The tester was prepared to emit a conduction (short circuit) signal when the applied voltage was 500 V and the resistance was 200 M ohms or less. The strip / wire / aluminum plate was heat-sealed at 190 ° C. and 1 MPa, and the time until a short-circuit signal was generated was measured. Table 2 shows the results.

(Observation of heat-sealed part after heat-sealing)
After cutting each of the battery packaging materials obtained in the above Examples and Comparative Examples into 80 mm x 150 mm, a forming die (female type) having a diameter of 35 mm x 50 mm and a forming die (male type) corresponding thereto. Then, cold forming was performed at 0.4 MPa to a depth of 1.0 mm, and a concave portion was formed at the center thereof. The concave portion was filled with 1 g of the above-mentioned electrolyte solution (ethylene carbonate, diethyl carbonate, dimethyl carbonate (1: 1: 1) made into 1M LiPF ₆ ), and another one for a battery package cut into a size of 80 mm × 150 mm. The material was overlapped from above the concave portion so that the sealant layers faced each other, and the peripheral edge was heat-sealed. The sheet sealing conditions were two types: (condition 1) 170 ° C., 0.5 MPa, 2.0 seconds, and (condition 2) 190 ° C., 1.0 MPa, 3.0 seconds. Thereafter, the electrolytic solution was removed, the heat-sealed portion was broken so as to be exposed, and the so-called "poly pool" portion of the heat-sealed portion was visually observed. Table 2 shows the results.

DESCRIPTION OF SYMBOLS 1 Base material layer 2 Adhesive layer 3 Stainless steel foil 3a, 3b Chemical conversion treatment layer 4 Sealant layer 5 Adhesive layer

Claims (9)

At least a base material layer, a stainless steel foil, an adhesive layer, and a battery packaging material comprising a laminate having a sealant layer in this order,
The total thickness of the laminate is 42 μm or more and 85 μm or less,
The thickness of the base material layer is not less than 5.5 μm and not more than 15 μm,
The thickness of the stainless steel foil is 15 μm or more and 40 μm or less,
At least on the sealant layer side of the stainless steel foil, a hydrogen fluoride-resistant chemical conversion treatment layer is formed,
The sealant layer is formed of polyolefin,
The total thickness of the laminate is T (μm), the thickness of the stainless steel foil is TS (μm), and the piercing strength of the laminate measured by a measuring method in accordance with JIS Z 1707 1997 is F (N). Wherein F is 19.2 N or more, F / T is 0.4 (N / μm) or more, and F / TS is 1.3 (N / μm) or more.   The packaging material for a battery according to claim 1, wherein the stainless steel foil is made of austenitic stainless steel.   The battery packaging material according to claim 1, wherein the stainless steel is SUS304.   The battery packaging material according to any one of claims 1 to 3, wherein the chemical conversion treatment layer is formed by a phosphoric acid chromate treatment using a resin.   The battery packaging material according to claim 4, wherein the resin used for the phosphoric acid chromate treatment is a phenol resin.   The battery packaging material according to any one of claims 1 to 5, wherein at least one of the layers located on the substrate layer side of the stainless steel foil is black. An adhesive layer is laminated between the base material layer and the stainless steel foil,
The battery packaging material according to any one of claims 1 to 6, wherein the adhesive layer is colored black.   The battery packaging material according to any one of claims 1 to 7, wherein the sealant layer has a melt flow rate (MFR) at 230 ° C of 15 g / 10 minutes or less. A battery, wherein a battery element including at least a positive electrode, a negative electrode, and an electrolyte is housed in the battery packaging material according to any one of claims 1 to 8 .