Battery packaging material

Abstract

To impart contradictory characteristics to the surface of a battery packaging material, such as preventing a protective tape from being peeled off inadvertently and allowing it to be removed without leaving any adhesive on a tape.SOLUTION: A battery packaging material 1 includes a base material layer 13, a heat-fusible resin layer 15, a barrier layer 11 arranged between these two layers, and a base material protective layer 20 that is provided as the outermost layer on the outside of the base material layer 13, and the base material protective layer 20 includes a binder resin 21, and soft resin fine particles with a glass transition point Tg of less than 30°C, hard resin fine particles with a glass transition point Tg of 30°C or higher, and inorganic fine particles as solid fine particles 22. The total content of the solid fine particles 22 in the base material protective layer 20 is 30 mass% to 50 mass%.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a packaging material for electricity storage devices such as batteries and capacitors used in portable devices such as smartphones and tablets, and batteries and capacitors used for storing electricity in electric vehicles, wind power generation, solar power generation, and nighttime electricity. [Background technology]

[0002] During the battery manufacturing process, scratches on the surface of the packaging material, which is the case material, can impair the product's appearance. To prevent such poor appearance during the manufacturing process, a protective tape is applied to the packaging material and then removed after the manufacturing process is complete. While the protective tape must adhere well enough to prevent peeling during the manufacturing process, if it is too tightly adhered, the adhesive of the protective tape may remain on the packaging material after peeling. Furthermore, in packaging materials with a colored layer containing carbon black laminated on the surface, the colored layer may peel off along with the protective tape.

[0003] To address these problems with protective tapes, the adhesive strength of the protective tape has been used to address the issue of adhesive residue after peeling the protective tape (see Patent Document 1). Also, a technique for strengthening the colored layer has been proposed to address peeling of the colored layer (see Patent Document 2). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 2020-155364 [Patent Document 2] Japanese Patent Application Laid-Open No. 2006-206805 Summary of the Invention [Problem to be solved by the invention]

[0005] However, the technology of Patent Document 1 is not a measure to prevent adhesive residue on packaging materials, and the technology of Patent Document 2 does not solve the problem of adhesive residue on packaging materials whose outermost layer is not a colored layer containing carbon black. [Means for solving the problem]

[0006] In view of the above-mentioned background art, the present invention aims to impart the contradictory properties of preventing unintentional peeling of a protective tape on the surface of a battery packaging material and enabling the tape to be peeled off without leaving any adhesive residue, and to prevent the appearance from being poor due to residual adhesive residue from the tape.

[0007] That is, the present invention has the configurations described in the following [1] to

[11] . [1] A packaging material for a battery having a substrate layer, a heat-sealable resin layer, a barrier layer disposed between these two layers, and a substrate protective layer as an outermost layer outside the substrate layer, the substrate protective layer contains a binder resin and, as solid fine particles, soft resin fine particles having a glass transition temperature Tg of less than 30°C, hard resin fine particles having a glass transition temperature Tg of 30°C or higher, and inorganic fine particles; The battery packaging material is characterized in that the total content of solid fine particles in the substrate protective layer is 30% by mass to 50% by mass.

[0008] [2] The battery packaging material according to item 1, wherein the soft resin fine particles have an average particle size of 5 μm to 20 μm, the hard resin fine particles have an average particle size of 1 μm to 15 μm, and the inorganic fine particles have an average particle size of 1 μm to 10 μm.

[0009] [3] The battery packaging material according to the preceding item 1 or 2, wherein the content of soft resin particles in the base material protective layer is 1% by mass to 10% by mass, the content of hard resin particles is 1% by mass to 20% by mass, and the content of inorganic particles is 20% by mass to 40% by mass.

[0010] [4] The battery packaging material according to any one of items 1 to 3 above, wherein the soft resin particles are at least one selected from the group consisting of polyethylene wax, polypropylene wax, polyethylene resin beads, and urethane resin beads.

[0011] [5] The battery packaging material according to any one of items 1 to 4 above, wherein the hard resin particles are at least one selected from polytetrafluoroethylene wax, acrylic resin beads, polystyrene resin beads, and fluororesin beads.

[0012] [6] The battery packaging material according to any one of items 1 to 5, wherein the inorganic fine particles are at least one selected from the group consisting of silica, alumina, kaolin, calcium oxide, calcium carbonate, calcium sulfate, barium sulfate, and calcium silicate.

[0013] [7] The battery packaging material according to any one of items 1 to 6, wherein the binder resin of the substrate protective layer is at least one selected from acrylic resins, urethane resins, polyolefin resins, phenoxy resins, polyester resins, and tetrafluoroolefin resins.

[0014] [8] The packaging material for a battery according to any one of items 1 to 7 above, wherein the substrate protective layer and / or the substrate layer contains a colorant.

[0015] [9] The battery packaging material according to any one of items 1 to 7, wherein the barrier layer and the base material layer are laminated via an adhesive layer, and at least one layer of the base material protective layer, the base material layer, and the adhesive layer contains a colorant.

[0016]

[10] The packaging material for a battery according to any one of items 1 to 7 above, further comprising a colored layer between the base protective layer and the substrate layer and / or between the substrate layer and the barrier layer.

[0017]

[11] The battery packaging material according to any one of items 1 to 7, wherein the barrier layer and the substrate layer are laminated via an adhesive layer, and a colored layer is provided between at least one of the layers between the base protective layer and the substrate layer, between the substrate layer and the adhesive layer, and between the adhesive layer and the barrier layer. [Effects of the Invention]

[0018] In the battery packaging material described in [1] above, the substrate protective layer contains a binder resin and solid particles of soft resin particles, hard resin particles, and inorganic particles with different hardnesses. Therefore, the surface is formed of a portion where the binder resin is present and a portion where three types of solid particles with different hardnesses are present. The portions where the binder resin is present are more likely to come into contact with the adhesive of the protective tape, resulting in strong adhesive strength, while the portions where the solid particles are present are less likely to come into contact with the adhesive, resulting in weak adhesive strength. Furthermore, since there are three types of solid particles with different hardnesses, the adhesive strength varies depending on the solid particles. Furthermore, since the total content of the solid particles is specified to be 30% by mass to 50% by mass, the areas of the strong adhesive and the weak adhesive are balanced, allowing the protective tape to maintain its adhesive strength when needed while being easily peeled off after use, and is less likely to leave adhesive residue after peeling.

[0019] Furthermore, when the battery packaging material is heated and pressurized during the curing process of battery manufacturing, the soft and hard resin particles soften and flatten according to their glass transition temperatures (Tg), improving the adhesiveness of the protective tape and making it difficult to peel. On the other hand, the inorganic particles are very hard and barely deform, maintaining the easy-to-peel effect, preventing significant deformation of the soft and hard resin particles, and suppressing their embedding in the binder resin. By using three types of solid particles with different hardness, it is possible to suppress the increase in adhesive strength due to heating and pressurization and maintain easy peelability.

[0020] According to the battery packaging material described in [2] above, the average particle diameters of the three types of solid fine particles are specified, so the timing at which the adhesive peels off is less likely to cause cohesive failure of the adhesive, and adhesive residue is less likely to occur.

[0021] According to the battery packaging material described in [3] above, the content of three types of solid fine particles is specified, and a large amount of inorganic fine particles is blended, which has a significant effect of inhibiting contact between the adhesive of the protective tape and the binder resin when heated and pressurized, thereby suppressing the occurrence of adhesive residue.

[0022] According to the battery packaging material described in [4] above, the selected soft resin particles soften and become easily deformed at the temperature during heating and pressurization, so that an appropriate peel strength can be obtained with respect to the adhesive of the protective tape.

[0023] According to the battery packaging material described in [5] above, the selected hard resin particles are slightly deformed by the synergistic effect of the temperature and pressure during heating and pressurization, so that the contact area with the adhesive of the protective tape increases slightly, contributing to the peel strength.

[0024] According to the battery packaging material described in [6] above, the selected inorganic fine particles are resistant to deformation when heated and pressurized, and therefore an appropriate peel strength can be obtained with the adhesive of the protective tape.

[0025] According to the battery packaging material described in [7] above, the adhesive suitability of the selected binder resin and the adhesive of the protective tape is good, so that it is possible to create a difference in adhesive strength between the part where the binder resin is present and the part where the solid fine particles are present.

[0026] The battery packaging materials described in [8], [9],

[10] and

[11] above can be colored with a coloring agent to improve the visibility of the adhesive residue of the protective tape, making it easier to determine the adhesive residue. They can also be designed. [Brief explanation of the drawings]

[0027] [Figure 1] FIG. 1 is a cross-sectional view showing an example of the battery packaging material of the present invention. [Figure 2] FIG. 2 is a cross-sectional view showing the state of the battery packaging material to which the protective tape has been attached when it is heated and pressurized. [Figure 3] FIG. 3 is a cross-sectional view showing another example of the battery packaging material of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0028] FIG. 1 shows one embodiment of the battery packaging material of the present invention.

[0029] In the following description, layers with the same reference numerals represent the same or equivalent parts, and redundant description will be omitted.

[0030] In this specification, when describing the position of each layer constituting the battery packaging material in terms of direction, the direction toward the base material protective layer is referred to as the outside, and the direction toward the heat-sealable resin layer is referred to as the inside. [Embodiment of Battery Packaging Material] The battery packaging material 1 in Figure 1 has a substrate layer 13 bonded to one surface of a barrier layer 11 via a first adhesive layer 12, a heat-sealable resin layer 15 bonded to the other surface via a second adhesive layer 14, and a substrate protective layer 20 laminated on the substrate layer 13. (Use of protective tape in the battery manufacturing process) A battery case is produced by forming a battery packaging material 1 into a three-dimensional shape to form convex portions and arranging the heat-sealable resin layers 15 facing each other. The battery element and electrolyte are filled into the case, the periphery of the convex portions is heat-sealed, and the battery is then cured and degassed to complete the battery. During the process from forming the battery packaging material 1 to degassing, protective tape is applied to the top surfaces of the convex portions and non-heat-sealed portions to protect the battery packaging material 1. Curing and degassing are performed while the protective tape is applied. The curing is performed by heating the battery packaging material 1 to 50°C to 80°C and applying a pressure of 0.3 MPa to 0.7 MPa in the stacking direction for 1 hour to 24 hours. Figure 2 shows the battery packaging material 1 with protective tape 50 attached during heating and pressurization. The protective tape 50 is a sheet of base material 51 with adhesive 52 applied to one side.

[0031] After the curing and degassing process is completed, the protective tape 50 is removed from the battery and the battery is then shipped.

[0032] Therefore, the outer surface of the battery packaging material 1 must be firmly attached to the protective tape 50 without it accidentally peeling off, but when the protective tape 50 is no longer needed, it must be able to be peeled off cleanly without leaving any adhesive 52 behind and without damaging the surface to which it was attached, which are contradictory properties. (Base material protective layer) The substrate protective layer 20 is a layer that imparts good slipperiness to the surface of the battery packaging material, improving formability, and also imparts excellent chemical resistance, solvent resistance, and abrasion resistance.

[0033] The substrate protective layer 20 is a cured film of a resin composition containing a binder resin 21 and three types of solid fine particles 22 described below. Some of the solid fine particles 22 in the cured film are buried in the binder resin 21, but some protrude outward from the surface to form protrusions 30. Therefore, the surface of the substrate protective layer 20 has not only very fine irregularities caused by the binder resin 21, but also large irregularities caused by the protrusions 30.

[0034] Because the protrusions 30 protrude high on the surface of the substrate protective layer 20, the adhesive of the protective tape comes into contact with the peaks of the protrusions 30 but is less likely to come into contact with the surrounding sloped portions. On the other hand, the portions excluding the protrusions 30 are smoother than the protrusions 30, making it easier for the adhesive to come into contact. The portions with less adhesive contact have a lower amount of adhesive, resulting in weaker adhesive strength (adhesion), while the portions with more adhesive contact have a higher amount of adhesive, resulting in stronger adhesive strength. In this way, the surface of the substrate protective layer 20 has a fine mixture of portions with a high and low amount of adhesive contact, allowing the layer to be easily peeled off after use while maintaining adhesive strength when needed, and is less likely to leave adhesive residue after peeling.

[0035] The balance between the adhesive strength of the protective tape when needed and its easy removability after use is affected by the composition of the resin composition that constitutes the substrate protective layer 20 and the characteristics of the solid microparticles used, and by specifying these, an appropriate balance can be obtained.

[0036] The resin composition constituting the substrate protective layer 20 contains a binder resin 21 and three types of solid particles 22: soft resin particles, hard resin particles, and inorganic particles. In the present invention, the hardness of the resin particles is distinguished based on their glass transition temperature (Tg), with resin particles with a glass transition temperature (Tg) of less than 30°C being defined as soft resin particles and resin particles with a glass transition temperature (Tg) of 30°C or higher being defined as hard resin particles. The glass transition temperature (Tg) is the temperature at which the molecular chains of the resin particles begin to undergo micro-Brownian motion, and is indicated by the onset temperature (onset point) of heat absorption in differential scanning calorimetry (DSC) analysis. The glass transition temperature (Tg) can be measured according to JIS K7121-1987, "Method for measuring transition temperatures of plastics."

[0037] The three types of solid particles differ in hardness, with soft resin particles being the softest and inorganic particles being the hardest. These three types of solid particles also differ in hardness from the cured binder resin 21. Because protrusions 30 are formed on the surface of the substrate protective layer 20 by the solid particles 22, the surface of the substrate protective layer 20 contains portions with different hardness due to the resin binder 21 and the three types of solid particles 22. The ease with which the adhesive of the protective tape separates also depends on the hardness of the application surface. Areas where the binder resin is present are more likely to come into contact with the adhesive of the protective tape, resulting in stronger adhesive strength, while areas where the solid particles are present are less likely to come into contact with the adhesive, resulting in weaker adhesive strength. Furthermore, because there are three types of solid particles with different hardness, the strength of adhesive strength also varies depending on the solid particles. When the protective tape is peeled off from the substrate protective layer 20 having the above-described surface, the timing of the adhesive peeling differs in areas with different hardness, dispersing the force applied to the adhesive. This is thought to reduce the likelihood of cohesive failure of the adhesive and the generation of adhesive residue.

[0038] As shown in Figure 2, the battery packaging material 1 undergoes heat and pressure curing after heat sealing during the battery manufacturing process while the protective tape 50 is attached. When the battery packaging material 1 is heated and pressurized in the stacking direction, changes occur in each of the three types of solid particles according to their characteristics. The soft resin particles 22a, which have a glass transition temperature Tg of less than 30°C, soften and deform flat, increasing their contact area with the adhesive 52, improving adhesion to the protective tape 50 and making it less likely to peel. The hard resin particles 22b, which have a glass transition temperature Tg of 30°C or higher, also soften, but deform less than the soft resin particles 22a. Therefore, the increase in their contact area with the adhesive 52 is commensurate, and their effect in enhancing adhesion is less than that of the soft resin particles 22a. The inorganic particles 22c are very hard and barely deform. Therefore, their contact area with the adhesive 52 remains unchanged, maintaining the easy-peeling effect of the protruding particles (protrusions 30). Furthermore, the inorganic fine particles 22c prevent significant deformation of the soft resin fine particles 22a and the hard resin fine particles 22b, and also suppress embedding of the soft resin fine particles 22a and the hard resin fine particles 22b in the binder resin 21. When the battery packaging material 1 is heated and pressurized, the adhesive strength of the protective tape 50 increases, but by using three types of solid fine particles with different hardness, it is possible to suppress the increase in adhesive strength due to heating and pressurization and maintain easy peelability.

[0039] The total content of solid particles in the substrate protective layer 20 is 30% to 50% by mass. If the total content of solid particles is less than 30% by mass, the protrusions 30 on the surface of the substrate protective layer 20 will be low and few, resulting in increased adhesion of the protective tape, increased peel strength, and increased likelihood of adhesive residue. On the other hand, if the total content of solid particles exceeds 50% by mass, adhesive residue will be less likely to occur, but on the other hand, the adhesion of the protective tape will be reduced, making it more likely for unintended peeling to occur during handling. A particularly preferred total content is 35% to 45% by mass.

[0040] The preferred content of each type of fine particle in the substrate protective layer 20 is 1% to 10% by mass for soft resin fine particles, 1% to 20% by mass for hard resin fine particles, and 20% to 40% by mass for inorganic fine particles. Particularly preferred contents of each type of fine particle are 2% to 8% by mass for soft resin fine particles, 3% to 12% by mass for hard resin fine particles, and 25% to 35% by mass for inorganic fine particles. Furthermore, the content of the three types of solid fine particles is preferably greater than the total content of the soft resin fine particles and the hard resin fine particles. The incorporation of a large amount of inorganic fine particles effectively inhibits contact between the adhesive and the binder resin of the protective tape during heating and pressure application, thereby suppressing adhesive residue. The total content of the solid fine particles and the content of each solid fine particle are the ratios to the total of the binder resin and the solid fine particles, and do not include solvents used to adjust viscosity during coating.

[0041] The soft resin microparticles preferably have an average particle size of 5 μm to 20 μm, the hard resin microparticles preferably have an average particle size of 1 μm to 15 μm, and the inorganic microparticles preferably have an average particle size of 1 μm to 10 μm. Particularly preferred average particle sizes are 6 μm to 18 μm for the soft resin microparticles, 3 μm to 12 μm for the soft resin microparticles, and 1 μm to 3 μm for the inorganic microparticles. Since the contact area with the adhesive of the protective tape varies depending on the particle size of the solid microparticles, and the adhesive strength varies, by setting the average particle sizes of the three types of solid microparticles within the above ranges, the timing of peeling of the adhesive is less likely to cause cohesive failure of the adhesive, and adhesive residue is less likely to occur.

[0042] Furthermore, it is preferable that the average particle diameters of the three types of solid particles satisfy the relationship soft resin particles > hard resin particles > inorganic particles. As described above, when heated and pressurized for battery curing, the soft resin particles and hard resin particles are deformed flat, increasing the contact area with the adhesive of the protective tape and increasing adhesive strength, while the inorganic particles do not deform, which has the effect of suppressing deformation of the two types of resin particles. When the average particle diameters of the three types of solid particles satisfy the above relationship, a good balance between adhesive strength and easy peelability is achieved, and the occurrence of adhesive residue is suppressed.

[0043] The solid fine particles must contain at least one type selected from the categories of soft resin fine particles, hard resin fine particles, and inorganic fine particles, and may contain two or more types from one category. Examples of fine particles belonging to each category include the following:

[0044] Examples of the soft resin microparticles, i.e., resin microparticles with a glass transition temperature Tg of less than 30°C, include polyethylene wax, polypropylene wax, polyethylene resin beads, and urethane resin beads. These microparticles can obtain an appropriate peel strength with respect to the adhesive of the protective tape due to their glass transition temperatures Tg. Among the soft resin microparticles described above, polyethylene wax and polyethylene resin beads have low glass transition temperatures Tg and melting points, and the softening point of polyethylene is 85 to 120°C. Therefore, they soften and become easily deformed at temperatures around the temperature (50 to 80°C) used in the heating and pressurizing step during curing. Therefore, they are recommended because they can easily improve the peel strength with the adhesive of the protective tape.

[0045] Examples of the hard resin microparticles, i.e., resin microparticles with a glass transition temperature Tg of 30° C. or higher, include polytetrafluoroethylene wax, acrylic resin beads, polystyrene resin beads, and fluororesin beads. All of these microparticles have a glass transition temperature Tg of around 100° C. and are unlikely to soften at the temperatures (50° C. to 80° C.) used in the heating and pressurizing process for curing after application of the protective tape, but they deform slightly due to the synergistic effect of pressure, slightly increasing the contact area with the adhesive of the protective tape and contributing to peel strength.

[0046] Furthermore, among the above hard resin particles, polytetrafluoroethylene wax has the best chemical resistance, and when electrolyte resistance is required for the substrate protective layer, it is preferable to use this wax.

[0047] Examples of the inorganic fine particles include silica, alumina, kaolin, calcium oxide, calcium carbonate, calcium sulfate, barium sulfate, and calcium silicate.All of these inorganic fine particles are harder than the soft resin fine particles and hard resin fine particles mentioned above, and are less likely to deform during the heating and pressing process, and can obtain appropriate peel strength with the adhesive of the protective tape.In addition, among these inorganic fine particles, silica is recommended because it has a variety of grades with small average particle diameters, and it is easy to obtain fine particles with the desired average particle diameter, and it is easy to disperse in various binder resins.

[0048] The binder resin 21 is preferably at least one resin selected from acrylic resins, urethane resins, polyolefin resins, phenoxy resins, and polyester resins. These resins have good adhesive suitability with the pressure-sensitive adhesive of the protective tape, allowing for a difference in adhesive strength between the area where the binder resin is present and the area where the solid particles are present. Furthermore, these resins have high chemical resistance and solvent resistance, making it difficult for the solid particles to fall off due to resin degradation, etc. Among these, particularly preferred resins are urethane resins, polyester urethane resins, and urethane phenoxy resins.

[0049] The binder resin may be a base resin containing at least one of the above-mentioned resins and a curing agent for curing the base resin. The curing agent is not particularly limited and may be selected appropriately depending on the base resin. Examples of the curing agent include isocyanate compounds such as hexamethylene diisocyanate (HDI), isophorone diisocyanate (IPDI), tolylene diisocyanate (TDI), diphenylmethane diisocyanate (MDI), and xylylene diisocyanate (XDI), as well as modified versions of these isocyanate compounds.

[0050] The curing agent is preferably blended in an amount of 5 to 30 parts by mass relative to 100 parts by mass of the main resin. If the amount is less than 5 parts by mass, adhesion to the substrate layer 13 and solvent resistance may decrease. If the amount is more than 30 parts by mass, the substrate protective layer 20 may become hard and moldability may decrease.

[0051] Furthermore, in addition to the binder resin 21 and the solid fine particles 22, a lubricant and / or a surfactant may be added to the substrate protective layer 20. The lubricant and surfactant have the effect of reducing the adhesive strength of the adhesive of the protective tape, and by precipitating these on the surface of the substrate protective layer 20, the protective tape can be easily peeled off and adhesive residue is less likely to occur.

[0052] Examples of the lubricant include the following various amides.

[0053] Examples of saturated fatty acid amides include lauric acid amide, palmitic acid amide, stearic acid amide, behenic acid amide, and hydroxystearic acid amide.

[0054] Examples of unsaturated fatty acid amides include oleic acid amide and erucic acid amide.

[0055] Examples of the substituted amide include N-oleyl palmitic acid amide, N-stearyl stearic acid amide, N-stearyl oleic acid amide, N-oleyl stearic acid amide, and N-stearyl erucic acid amide.

[0056] The methylol amide may include methylol stearamide.

[0057] Examples of saturated fatty acid bisamides include methylene bisstearic acid amide, ethylene biscapric acid amide, ethylene bislauric acid amide, ethylene bisstearic acid amide, ethylene bishydroxystearic acid amide, ethylene bisbehenic acid amide, hexamethylene bisstearic acid amide, hexamethylene bisbehenic acid amide, hexamethylene hydroxystearic acid amide, N,N'-distearyl adipic acid amide, and N,N'-distearyl sebacic acid amide.

[0058] Examples of unsaturated fatty acid bisamides include ethylene bisoleic acid amide, ethylene biserucic acid amide, hexamethylene bisoleic acid amide, N,N'-dioleyl adipamide, and N,N'-dioleyl sebacic acid amide.

[0059] The fatty acid ester amide may include stearamidoethyl stearate.

[0060] Examples of aromatic bisamides include m-xylylene bisstearic acid amide, m-xylylene bishydroxystearic acid amide, and N,N'-cystearyl isophthalic acid amide.

[0061] Examples of the surfactant include anionic surfactants, cationic surfactants, and nonionic surfactants.

[0062] The thickness of the substrate protective layer 20 is preferably 1 μm to 12 μm, and particularly preferably 2 μm to 10 μm.

[0063] In the battery packaging material 1, the preferred materials for the layers other than the substrate protective layer 20 are as follows. (barrier layer) The barrier layer 11 serves to impart gas barrier properties to the battery packaging material 1, preventing the intrusion of oxygen and moisture. The barrier layer 11 is not particularly limited, and examples thereof include metal foils such as aluminum foil, SUS foil (stainless steel foil), copper foil, nickel foil, titanium foil, and clad foil. Among these, aluminum foil is particularly suitable for use as the barrier layer 11. In particular, when an Al-Fe alloy foil containing 0.7% to 1.7% by mass of Fe is used, it exhibits excellent strength and ductility, resulting in favorable formability. The thickness of the barrier layer 11 is preferably 20 μm to 100 μm. Having a thickness of 20 μm or more can prevent pinholes from occurring during rolling in the production of the metal foil, while having a thickness of 100 μm or less can reduce stress during forming processes such as stretch forming and drawing, thereby improving formability. A particularly preferred thickness of the barrier layer 11 is 30 μm to 80 μm.

[0064] Furthermore, it is preferable that the barrier layer 11 is subjected to a surface treatment such as chemical conversion treatment at least on the surface of the metal foil facing the heat-sealable resin layer 15. By performing such a chemical conversion treatment, corrosion of the metal foil surface due to the contents (such as the electrolyte of the battery) can be sufficiently prevented. (base material layer) The base layer 13 is made of a heat-resistant resin film that does not melt at the heat-sealing temperature when the battery packaging material 1 is heat-sealed. The heat-resistant resin has a melting point that is at least 10°C higher, preferably at least 20°C higher, than the melting point of the resin constituting the heat-sealable resin layer 15. Examples of resins that satisfy this condition include polyamide films such as nylon film and polyester films, and oriented films of these films are preferred. Among these, biaxially oriented polyamide films such as biaxially oriented nylon film, biaxially oriented polybutylene terephthalate (PBT) film, biaxially oriented polyethylene terephthalate (PET) film, or biaxially oriented polyethylene naphthalate (PEN) film are particularly preferred for the base layer 13. The nylon film is not particularly limited, but examples include nylon 6 film, nylon 6,6 film, and MXD nylon film. The base layer 13 may be formed as a single layer, or may be formed as a multi-layer structure made of, for example, a polyester film / polyamide film (such as a multi-layer structure made of a PET film / nylon film).

[0065] The thickness of the base material layer 13 is preferably 9 μm to 50 μm, which ensures sufficient strength as a packaging material and improves formability by reducing stress during molding such as stretch molding and drawing. The thickness of the base material layer 13 is more preferably 12 μm to 30 μm. (thermal adhesive resin layer) The heat-sealable resin layer 15 provides excellent chemical resistance to highly corrosive electrolytes and the like, and also serves to impart heat-sealing properties to the battery packaging material 1 .

[0066] The resin constituting the heat-sealable resin layer 15 is preferably a single-layer or multilayer film of a polyolefin-based resin such as a propylene-based resin, and preferably a non-stretched film. An example of the propylene-based resin is an ethylene-propylene copolymer containing ethylene and propylene as copolymerization components. The ethylene-propylene copolymer may be either a random copolymer or a block copolymer. A recommended multilayer ethylene-propylene copolymer film is a three-layer film of a random copolymer-block copolymer-random copolymer. The multilayer film can be produced by coextrusion or the like.

[0067] The thickness of the heat-sealable resin layer 15 is preferably 20 μm to 100 μm, and more preferably 30 μm to 80 μm. The thickness ratio of the layers in the three-layer film of random copolymer-block copolymer-random copolymer is preferably 1-3:4-8:1-3.

[0068] The heat-sealable resin layer 15 may contain a lubricant. The type of lubricant is similar to that added to the substrate protective layer 20 described above, with fatty acid amide being particularly preferred. The lubricant concentration in the heat-sealable resin layer 15 is preferably 500 ppm to 3000 ppm. Generally, in the manufacturing process of the battery packaging material 1, after all layers have been laminated, the material is wound up on a roll and aged. The lubricant in the heat-sealable resin layer 15 precipitates on the surface by aging and is transferred to the substrate protective layer 20, contributing to the prevention of adhesive residue from the protective tape. (First adhesive layer) The first adhesive layer 12 is not particularly limited, and examples thereof include an adhesive layer formed of a two-component curing adhesive. Examples of the two-component curing adhesive include a two-component curing adhesive composed of a first component (base) made of one or more polyols selected from the group consisting of polyurethane polyols, polyester polyols, polyether polyols, and polyester urethane polyols, and a second component (curing agent) made of an isocyanate. Among these, it is preferable to use a two-component curing adhesive composed of a first component made of one or more polyols selected from the group consisting of polyester polyols and polyester urethane polyols, and a second component (curing agent) made of an isocyanate. The preferred thickness of the first adhesive layer 12 is 2 μm to 5 μm. (Second adhesive layer) The second adhesive layer 14 is not particularly limited, but may be, for example, an adhesive containing one or more of polyurethane resin, acrylic resin, epoxy resin, polyolefin resin, elastomer resin, fluorine resin, or acid-modified polypropylene resin. Among these, an adhesive made of a polyurethane composite resin containing acid-modified polyolefin as a main component is preferred. The second adhesive layer 14 preferably has a thickness of 2 μm to 5 μm.

[0069] The first adhesive layer 12 and the second adhesive layer 14 are not essential layers, and the base material layer 13 may be directly bonded to the barrier layer 11, or the heat-fusible resin layer 15 may be directly bonded to the barrier layer 11. (coloring agent) By adding a colorant to the existing layer described above or by providing a new colored layer, the battery packaging material can be colored to a desired color while concealing the metallic color of the barrier layer, thereby imparting design features to the packaging material and making it easier to detect any remaining adhesive on the protective tape.

[0070] When coloring an existing layer, a colorant is added to at least one of the substrate protective layer, substrate layer, and first adhesive layer. In battery packaging materials that do not have a first adhesive layer, the colorant is added to the substrate protective layer and / or substrate layer. The colorant may be a pigment or a dye, and one type or two or more types of colorants may be used in combination. Specific examples of colorants include carbon black, calcium carbonate, titanium oxide, zinc oxide, iron oxide, aluminum powder, azo pigments, and phthalocyanine pigments. The colorant concentration in each layer is preferably in the range of 0.5% by mass or more and less than 5% by mass.

[0071] When a new colored layer is provided, it is provided between at least one of the layers between the substrate protective layer and the substrate layer, between the substrate layer and the first adhesive layer, and between the first adhesive layer and the barrier layer. In battery packaging materials that do not have a first adhesive layer, the colored layer is provided between the substrate protective layer and the substrate layer and / or between the substrate layer and the barrier layer. The thickness of the colored layer is preferably 1 μm to 10 μm. The colored layer is preferably composed of a colored resin composition in which the above-mentioned colorant is added to a base resin composed of a main agent such as a diamine or polyol and a curing agent. The colorant concentration in this colored resin composition is preferably in the range of 5% by mass to 50% by mass.

[0072] The battery packaging material 2 in FIG. 3 has a colored layer 16 provided between the base material layer 13 and the first adhesive layer 12. [Example]

[0073] As an example and a comparative example, a battery packaging material 2 having the structure shown in Fig. 3 was produced. The materials common to each example are as follows. (Common material) The barrier layer 11 was prepared by applying a chemical conversion treatment solution consisting of phosphoric acid, polyacrylic acid (acrylic resin), a chromium (III) salt compound, water, and alcohol to both sides of a 40 μm-thick aluminum foil made of A8021-O, followed by drying at 180° C. The chromium deposition amount of this chemical conversion film was 10 mg / m per side. 2 is.

[0074] As the base layer 13, a biaxially oriented nylon 6 film having a thickness of 15 μm was used.

[0075] A colored resin composition containing carbon black, diamine, polyester polyol, and a curing agent was applied to one side of the base layer 13 to form the colored layer 16, and the composition was left to stand for one day in a 40°C environment to allow a crosslinking reaction to proceed as the layer dried, thereby forming a 3 μm-thick black colored layer. That is, the colored layer 16 and the base layer 13 were integrated into a two-layer film, which was then laminated to another layer.

[0076] As the heat-fusible resin layer 15, a 30 μm thick unstretched polypropylene film containing 3000 ppm of erucic acid amide as a lubricant was used.

[0077] As the first adhesive layer 12, a two-component curing urethane adhesive was used.

[0078] As the second adhesive layer 14, a two-component curing type maleic acid modified propylene adhesive was used.

[0079] As a solvent to be added to the resin composition of the substrate protective layer 20, a mixture of 50 parts by mass of methyl ethyl ketone and 50 parts by mass of toluene was used. Example 1 A resin composition for forming the substrate protective layer 20 and a coating composition were prepared by the following methods.

[0080] The binder resin was prepared by blending 49 parts by mass of the base resin with 11 parts by mass of the curing agent, using polyester polyol resin as the base resin and an adduct of trimethylolpropane and hexamethylene diisocyanate (HDI) (referred to as "A" in Table 1) as the curing agent.

[0081] The solid particles used were polyethylene wax as soft resin particles, acrylic resin beads as hard resin particles, and silica and barium sulfate as inorganic particles. The average particle size of each solid particle and the glass transition temperatures Tg of the soft and hard resin particles are shown in Table 1.

[0082] A resin composition was prepared by blending four types of solid fine particles with the binder resin in the content ratios shown in Table 1, and then mixing 50 parts by mass of the resin composition with 100 parts by mass of a solvent to prepare a coating composition. The total content of the solid fine particles in the resin composition is as shown in Table 1.

[0083] A 3 μm thick first adhesive layer 12 was then formed on one surface of the barrier layer 11, and the surface of the colored layer 16 of the base material layer 13 (two-layer film) with the colored layer 16 was overlaid with the first adhesive layer 12 interposed therebetween, and dry laminated. Next, a 3 μm thick second adhesive layer 14 was formed on the other surface of the barrier layer 11, and the heat-sealable resin layer 15 was overlaid with the second adhesive layer 14 interposed therebetween, and dry laminated by sandwiching and pressing between a rubber nip roll and a laminating roll heated to 100° C. This resulted in a six-layer film in which, from outside to inside, the base material layer 13, colored layer 16, first adhesive layer 12, barrier layer 11, second adhesive layer 14, and heat-sealable resin layer 15 were laminated.

[0084] Next, a coating composition for the substrate protective layer 20 was applied to the surface of the substrate layer 13 of the six-layer laminate film, dried, wound up on a roll, and aged for 10 hours at 40° C. The thickness of the substrate protective layer 20 after aging was 2.5 μm, and a battery packaging material 2 with a seven-layer structure was thus obtained. Example 2 A resin composition for forming the substrate protective layer 20 and a coating composition were prepared by the following methods.

[0085] The same base resin and curing agent as in Example 1 were mixed in a ratio of 48 parts by mass of base resin to 10 parts by mass of curing agent to prepare a binder resin.

[0086] The solid particles used were polyethylene wax as soft resin particles, polystyrene resin beads as hard resin particles, and silica and barium sulfate as inorganic particles. The average particle size of each solid particle and the glass transition temperatures Tg of the soft and hard resin particles are shown in Table 1.

[0087] A resin composition was prepared by blending four types of solid fine particles with the binder resin in the content ratios shown in Table 1, and then mixing 50 parts by mass of the resin composition with 100 parts by mass of a solvent to prepare a coating composition. The total content of the solid fine particles in the resin composition is as shown in Table 1.

[0088] A battery packaging material 2 having a seven-layer structure was produced in the same manner as in Example 1, except for the resin composition and coating composition for the base protective layer 20. The thickness of the base protective layer 20 after aging was 2.5 μm. Example 3 A resin composition for forming the substrate protective layer 20 and a coating composition were prepared by the following methods.

[0089] The binder resin was prepared by blending acrylic polyol as the base resin and the same curing agent as in Example 1 in a ratio of 46 parts by mass of the base resin to 9 parts by mass of the curing agent.

[0090] The solid particles used were polyethylene resin beads as soft resin particles, polytetrafluoroethylene wax as hard resin particles, and alumina and barium sulfate as inorganic particles. The average particle size of each solid particle and the glass transition temperatures Tg of the soft and hard resin particles are shown in Table 1.

[0091] A resin composition was prepared by blending four types of solid fine particles with the binder resin in the content ratios shown in Table 1, and then mixing 50 parts by mass of the resin composition with 100 parts by mass of a solvent to prepare a coating composition. The total content of the solid fine particles in the resin composition is as shown in Table 1.

[0092] A battery packaging material 2 having a seven-layer structure was produced in the same manner as in Example 1, except for the resin composition and coating composition for the base protective layer 20. The thickness of the base protective layer 20 after aging was 2 μm. Example 4 A resin composition for forming the substrate protective layer 20 and a coating composition were prepared by the following methods.

[0093] The binder resin was a copolymer of tetrafluoroolefin and vinyl carboxylic acid ester as the base resin, and the same curing agent as in Example 1 was used, with 43 parts by mass of the base resin blended with 8 parts by mass of the curing agent.

[0094] The solid particles used were polyethylene resin beads as soft resin particles, polytetrafluoroethylene wax as hard resin particles, and silica and barium sulfate as inorganic particles. The average particle size of each solid particle and the glass transition temperatures Tg of the soft and hard resin particles are shown in Table 1.

[0095] A resin composition was prepared by blending four types of solid fine particles with the binder resin in the content ratios shown in Table 1, and then mixing 50 parts by mass of the resin composition with 100 parts by mass of a solvent to prepare a coating composition. The total content of the solid fine particles in the resin composition is as shown in Table 1.

[0096] A battery packaging material 2 having a seven-layer structure was produced in the same manner as in Example 1, except for the resin composition and coating composition for the base protective layer 20. The thickness of the base protective layer 20 after aging was 1.5 μm. Example 5 A resin composition for forming the substrate protective layer 20 and a coating composition were prepared by the following methods.

[0097] The same base resin and curing agent as in Example 1 were used, and a binder resin was prepared by blending 53 parts by mass of the base resin with 12 parts by mass of the curing agent.

[0098] The solid particles used were polyethylene wax as soft resin particles, polystyrene resin beads as hard resin particles, and alumina and calcium carbonate as inorganic particles. The average particle size of each solid particle and the glass transition temperatures Tg of the soft and hard resin particles are shown in Table 1.

[0099] A resin composition was prepared by blending four types of solid fine particles with the binder resin in the content ratios shown in Table 1, and then mixing 50 parts by mass of the resin composition with 100 parts by mass of a solvent to prepare a coating composition. The total content of the solid fine particles in the resin composition is as shown in Table 1.

[0100] A battery packaging material 2 having a seven-layer structure was produced in the same manner as in Example 1, except for the resin composition and coating composition for the base protective layer 20. The thickness of the base protective layer 20 after aging was 3 μm. Example 6 A resin composition for forming the substrate protective layer 20 and a coating composition were prepared by the following methods.

[0101] The binder resin was prepared by blending 46 parts by mass of the base resin with 10 parts by mass of the curing agent, using a polyurethane polyol resin as the base resin and a mixture of equal parts of an adduct of trimethylolpropane and hexamethylene diisocyanate (HDI) and an adduct of trimethylolpropane and toluene diisocyanate (TDI) (referred to as "B" in Table 1) as the curing agent.

[0102] Four types of solid particles were used: urethane resin beads as soft resin particles, acrylic resin beads as hard resin particles, and silica and barium carbonate as inorganic particles. The average particle size of each solid particle and the glass transition temperatures Tg of the soft and hard resin particles are shown in Table 1.

[0103] A resin composition was prepared by blending four types of solid fine particles with the binder resin in the content ratios shown in Table 1, and then mixing 50 parts by mass of the resin composition with 100 parts by mass of a solvent to prepare a coating composition. The total content of the solid fine particles in the resin composition is as shown in Table 1.

[0104] A battery packaging material 2 having a seven-layer structure was produced in the same manner as in Example 1, except for the resin composition and coating composition for the base protective layer 20. The thickness of the base protective layer 20 after aging was 2 μm. Example 7 A resin composition for forming the substrate protective layer 20 and a coating composition were prepared by the following methods.

[0105] The same binder resin as in Example 1 was used.

[0106] The solid fine particles used were the same soft and hard resin fine particles as in Example 1, and three types of silica were used as inorganic fine particles. The average particle size of each solid fine particle and the glass transition temperature Tg of the soft and hard resin fine particles are shown in Table 1.

[0107] A resin composition was prepared by blending three types of solid fine particles with the binder resin in the content ratios shown in Table 1, and then mixing 50 parts by mass of the resin composition with 100 parts by mass of a solvent to prepare a coating composition. The total content of the solid fine particles in the resin composition is as shown in Table 1.

[0108] A battery packaging material 2 having a seven-layer structure was produced in the same manner as in Example 1, except for the resin composition and coating composition for the base protective layer 20. The thickness of the base protective layer 20 after aging was 2.5 μm. (Comparative Example 1) A resin composition for forming the substrate protective layer 20 and a coating composition were prepared by the following methods.

[0109] The same base resin and curing agent as in Example 1 were used, and a binder resin was prepared by blending 60 parts by mass of the base resin with 12 parts by mass of the curing agent.

[0110] The solid particles used were polystyrene resin beads and acrylic resin beads as hard resin particles, and silica and barium sulfate as inorganic particles. Table 1 shows the average particle size of each solid particle and the glass transition temperatures Tg of the soft and hard resin particles.

[0111] A resin composition was prepared by blending four types of solid fine particles with the binder resin in the content ratios shown in Table 1, and then mixing 50 parts by mass of the resin composition with 100 parts by mass of a solvent to prepare a coating composition. The total content of the solid fine particles in the resin composition is as shown in Table 1.

[0112] A battery packaging material 2 having a seven-layer structure was produced in the same manner as in Example 1, except for the resin composition and coating composition for the base protective layer 20. The thickness of the base protective layer 20 after aging was 3 μm. (Comparative Example 2) A resin composition for forming the substrate protective layer 20 and a coating composition were prepared by the following methods.

[0113] The same base resin and curing agent as in Example 3 were used, and a binder resin was prepared by blending 37 parts by mass of the base resin with 8 parts by mass of the curing agent.

[0114] The solid particles used were acrylic resin beads and polytetrafluoroethylene wax as hard resin particles, and alumina and barium sulfate as inorganic particles. Table 1 shows the average particle size of each solid particle and the glass transition temperatures Tg of the soft and hard resin particles.

[0115] A resin composition was prepared by blending four types of solid fine particles with the binder resin in the content ratios shown in Table 1, and then mixing 50 parts by mass of the resin composition with 100 parts by mass of a solvent to prepare a coating composition. The total content of the solid fine particles in the resin composition is as shown in Table 1.

[0116] A battery packaging material 2 having a seven-layer structure was produced in the same manner as in Example 1, except for the resin composition and coating composition for the base protective layer 20. The thickness of the base protective layer 20 after aging was 2 μm. (Comparative Example 3) A resin composition for forming the substrate protective layer 20 and a coating composition were prepared by the following methods.

[0117] The same binder resin as in Example 1 was used.

[0118] The solid particles used were not soft resin particles, but acrylic resin beads as hard resin particles, and silica and barium sulfate as inorganic particles. The average particle size of each solid particle and the glass transition temperature Tg of the hard resin particles are shown in Table 1.

[0119] A resin composition was prepared by blending three types of solid fine particles with the binder resin in the content ratios shown in Table 1, and then mixing 50 parts by mass of the resin composition with 100 parts by mass of a solvent to prepare a coating composition. The total content of the solid fine particles in the resin composition is as shown in Table 1.

[0120] A battery packaging material 2 having a seven-layer structure was produced in the same manner as in Example 1, except for the resin composition and coating composition for the base protective layer 20. The thickness of the base protective layer 20 after aging was 2.5 μm. Comparative Example 4 A resin composition for forming the substrate protective layer 20 and a coating composition were prepared by the following methods.

[0121] The same binder resin as in Example 1 was used.

[0122] The solid particles used were polyethylene wax as soft resin particles, no hard resin particles, and three types of inorganic particles: silica and barium sulfate. The average particle size of each solid particle and the glass transition temperature Tg of the soft resin particles are shown in Table 1.

[0123] A resin composition was prepared by blending three types of solid fine particles with the binder resin in the content ratios shown in Table 1, and then mixing 50 parts by mass of the resin composition with 100 parts by mass of a solvent to prepare a coating composition. The total content of the solid fine particles in the resin composition is as shown in Table 1.

[0124] A battery packaging material 2 having a seven-layer structure was produced in the same manner as in Example 1, except for the resin composition and coating composition for the base protective layer 20. The thickness of the base protective layer 20 after aging was 2.5 μm. (Comparative Example 5) A resin composition for forming the substrate protective layer 20 and a coating composition were prepared by the following methods.

[0125] The same binder resin as in Example 1 was used.

[0126] The solid particles used were polyethylene wax as soft resin particles, acrylic resin beads as hard resin particles, and barium sulfate as inorganic particles. The average particle size of each solid particle and the glass transition temperature Tg of the soft resin particles are shown in Table 1.

[0127] A resin composition was prepared by blending three types of solid fine particles with the binder resin in the content ratios shown in Table 1, and then mixing 50 parts by mass of the resin composition with 100 parts by mass of a solvent to prepare a coating composition. The total content of the solid fine particles in the resin composition is as shown in Table 1.

[0128] A battery packaging material 2 having a seven-layer structure was produced in the same manner as in Example 1, except for the resin composition and coating composition for the base protective layer 20. The thickness of the base protective layer 20 after aging was 2.5 μm.

[0129] [Table 1]

[0130] In Table 1, the abbreviations for the main resin, soft resin particles, and hard resin particles are as follows: (Main resin) PEs: Polyester polyol resin, AC: Acrylic polyol resin TFE: Copolymer of tetrafluoroethylene and vinyl carboxylic acid ester PUR: Polyurethane polyol resin (Soft resin fine particles) PEW: Polyethylene wax, PEB: Polyethylene resin beads URB: urethane resin beads), PPW: polypropylene wax (hard resin particles) ACB: acrylic resin beads, PTFE: polytetrafluoroethylene wax PSB: Polystyrene resin beads The battery packaging material 2 of each example was measured and evaluated for the following items. The results are shown in Table 1. (Moldability) A number of test pieces measuring 100 mm x 125 mm were cut out from the produced battery packaging material 2, and these test pieces were subjected to deep drawing at various depths using a molding machine manufactured by Amada Co., Ltd. (product number: TP-25C-XZ) with a punch having a top surface dimension of 33 mm x 54 mm, a corner R of 2 mm, and a punch shoulder R of 1.3 mm, and a die having a die shoulder R of 1 mm.

[0131] The deep-drawn molded product was inspected for pinholes and cracks at the corners by a light transmission method in a dark room, and the depth at which no pinholes or cracks occurred was defined as the maximum forming depth (mm) of the battery packaging material 2. The maximum forming depth was evaluated based on the following criteria, with ◎ and ◯ being considered acceptable. ◎: Maximum forming depth is 5.5 mm or more ○: Maximum forming depth is less than 4.5mm to 5.5mm ×: Maximum forming depth is less than 4.5 mm (Tape adhesion) A test piece measuring 15 mm in width and 150 mm in length was cut out from the battery packaging material 2. A 5 mm in width, 80 mm in length, adhesive tape (tesa 70415) with an adhesive strength of 13 N / cm was attached to the substrate protective layer 20 of this test piece along the longitudinal direction of the test piece. A hand roll weighing 2 kgf was then run back and forth over this adhesive tape five times, and then the tape was left to stand at room temperature for 1 hour.

[0132] Next, using a Shimadzu Strograph (AGS-5kNX) tensile tester, one end of the test piece was clamped and fixed with one chuck, and the other end of the adhesive tape was gripped with the other chuck. Then, in accordance with JIS K6854-3 (1999), the peel strength was measured when peeled at an angle of 180° at a peel rate of 300 mm / min, and the value at which this measurement value stabilized was taken as the adhesion strength (unit: N / 5 mm) between the test piece and the adhesive tape.

[0133] The adhesive strength between the test piece and the adhesive tape was evaluated according to the following criteria, with ⊚ and ◯ being considered acceptable.

[0134] ◎: 7N / 5mm or more, very high adhesion 〇: 5N / 5mm or more and less than 7N / 5mm, high adhesion ×: Less than 5N / 5mm, poor adhesion (glue residue) A test piece measuring 50 mm in width and 100 mm in length was cut out from the battery packaging material 2. A 40 mm in width, 60 mm in length, adhesive tape (Nitto Denko V420) with an adhesive strength of 0.1 N / cm was attached to the substrate protective layer 20 of the test piece along the longitudinal direction of the test piece. A hand roll weighing 2 kgf was then run back and forth over the adhesive tape five times. The test piece with the adhesive tape attached was then heat-pressed at 80°C and 0.5 MPa.

[0135] After the series of treatments, the adhesive tape was quickly peeled off by hand from the test piece, and the peeled surface was observed and evaluated according to the following criteria, with ⊚, ◯, and △ being acceptable.

[0136] ◎: No change in surface condition compared to before application of sticker 〇: Small pieces of adhesive remained that could be removed by wiping lightly. △: It can be removed by wiping, but there are still larger pieces of adhesive remaining than 〇 ×: Adhesive remained firmly on the surface, but was not easily removed by wiping. From Table 1, it was confirmed that by specifying the solid fine particles in the substrate protective layer, the adhesiveness of the protective tape was improved and adhesive residue upon peeling could be suppressed. [Industrial Applicability]

[0137] The battery packaging material of the present invention can be suitably used as a packaging material for electricity storage devices such as batteries and capacitors used in portable devices such as smartphones and tablets, and batteries and capacitors used in electric vehicles, wind power generation, solar power generation, and nighttime electricity storage. [Explanation of symbols]

[0138] 1, 2...Battery packaging material 11...Barrier layer 12...First adhesive layer 13...Base material layer 14...Second adhesive layer 15…Thermofusible resin layer 16...Colored layer 20…Base material protective layer 21...Binder resin 22...Solid fine particles 22a…Soft resin fine particles 22b…Hard resin fine particles 22c...Inorganic fine particles 30...Protrusion

Claims

1. A packaging material for a battery, comprising a substrate layer, a heat-sealable resin layer, a barrier layer disposed between the two layers, and a substrate protective layer as an outermost layer outside the substrate layer, the substrate protective layer contains a binder resin and, as solid fine particles, soft resin fine particles having a glass transition temperature Tg of less than 30°C, hard resin fine particles having a glass transition temperature Tg of 30°C or higher, and inorganic fine particles; The battery packaging material is characterized in that the total content of solid fine particles in the substrate protective layer is 30% by mass to 50% by mass.

2. 2. The battery packaging material according to claim 1, wherein the soft resin fine particles have an average particle size of 5 μm to 20 μm, the hard resin fine particles have an average particle size of 1 μm to 15 μm, and the inorganic fine particles have an average particle size of 1 μm to 10 μm.

3. 3. The battery packaging material according to claim 1, wherein the content of soft resin particles in the substrate protective layer is 1% by mass to 10% by mass, the content of hard resin particles is 1% by mass to 20% by mass, and the content of inorganic particles is 20% by mass to 40% by mass.

4. 3. The battery packaging material according to claim 1, wherein the soft resin particles are at least one selected from the group consisting of polyethylene wax, polypropylene wax, polyethylene resin beads, and urethane resin beads.

5. 3. The battery packaging material according to claim 1, wherein the hard resin particles are at least one selected from the group consisting of polytetrafluoroethylene wax, acrylic resin beads, polystyrene resin beads, and fluororesin beads.

6. 3. The battery packaging material according to claim 1, wherein the inorganic fine particles are at least one selected from the group consisting of silica, alumina, kaolin, calcium oxide, calcium carbonate, calcium sulfate, barium sulfate, and calcium silicate.

7. 3. The battery packaging material according to claim 1, wherein the binder resin of the substrate protective layer is at least one selected from the group consisting of acrylic resins, urethane resins, polyolefin resins, phenoxy resins, polyester resins, and tetrafluoroolefin resins.

8. 3. The battery packaging material according to claim 1, wherein the substrate protective layer and / or the substrate layer contains a colorant.

9. 3. The battery packaging material according to claim 1, wherein the barrier layer and the substrate layer are laminated via an adhesive layer, and at least one layer of the substrate protective layer, the substrate layer, and the adhesive layer contains a colorant.

10. 3. The battery packaging material according to claim 1, further comprising a colored layer between the base protective layer and the substrate layer and / or between the substrate layer and the barrier layer.

11. 3. The battery packaging material according to claim 1, wherein the barrier layer and the substrate layer are laminated via an adhesive layer, and a colored layer is provided between at least one of the layers between the base protective layer and the substrate layer, between the substrate layer and the adhesive layer, and between the adhesive layer and the barrier layer.

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