JP2022020772A - Exterior material for power storage device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an exterior material for a power storage device that is excellent in moldability, capable of securing good printability on a surface, and being excellent in solvent resistance.

SOLUTION: An exterior material for a power storage device includes: a base layer made of heat-resistant resin; a sealant layer as an inner layer; and a metallic foil layer disposed between the base layer and the sealant layer. A protection layer is laminated on a surface of a base layer opposite to a metallic foil layer side. The protection layer is configured to include, at least on respective both ends independently, 40 mass% or more of polyester polyol of 5000-50000 of a number average molecular weight having a hydroxyl group or a carboxyl group and polyester resin formed of polyfunctional isocyanate curing agent containing at least an aliphatic polyfunctional isocyanate compound.

SELECTED DRAWING: Figure 1

COPYRIGHT: (C)2022,JPO&INPIT

Description

The present invention is for storage devices such as batteries and capacitors used in portable devices such as smartphones and tablets, hybrid vehicles, electric vehicles, wind power generation, solar power generation, and nighttime electricity storage. The present invention relates to an exterior material and a power storage device exteriorized by the exterior material.

In addition, in the claims of the present application and the present specification, the term "polyester polyol" is used.
1) Polyester having hydroxyl groups at both ends in the length direction of the main chain 2) Polyester having carboxyl groups at both ends in the length direction of the main chain 3) Hydroxyl groups at one end in the length direction of the main chain It is used in the sense of including polyester having a carboxyl group at the other end.

In recent years, as mobile electric devices such as smartphones and tablet terminals have become thinner and lighter, storage devices such as lithium ion secondary batteries, lithium polymer secondary batteries, lithium ion capacitors, and electric double-layer capacitors mounted on these devices have become thinner and lighter. As the exterior material, a laminate consisting of a heat-resistant resin layer (base material layer) / adhesive layer / metal foil layer / adhesive layer / thermoplastic resin layer (inner sealant layer) is used instead of the conventional metal can. (See Patent Document 1). In addition, power supplies for electric vehicles, large power supplies for power storage, capacitors, and the like are increasingly being exteriorized with the laminate (exterior material) having the above configuration. By overhanging or deep drawing the laminated body, it is formed into a three-dimensional shape such as a substantially rectangular parallelepiped shape. By molding into such a three-dimensional shape, it is possible to secure an accommodation space for accommodating the main body of the power storage device.

Further, in order to protect the exterior material and improve the moldability (slipperiness), a structure in which a matte varnish layer (protective layer) is provided on the outside of the base material layer has also been proposed. The matte varnish layer includes, for example, cellulose-based, polyamide-based, salt-and-vinegar-based, modified polyolefin-based, rubber-based, acrylic-based, urethane-based olefin-based, or alkyd-based synthetic resin, and silica-based, kaolin-based, or other inorganic. It is described that a matte varnish to which an appropriate amount of a material-based matting agent is added is used (see Patent Document 2).

Japanese Patent Application Laid-Open No. 2003-288865 Japanese Unexamined Patent Publication No. 2011-54563

By the way, for example, in the exterior material for a battery, the electrolytic solution (solvent-containing) may adhere to the surface (outer surface) of the exterior material when the electrolytic solution is injected into the inside of the main body in the battery manufacturing process. If the solvent resistance of the outer surface of the exterior material is not good, the appearance of the exterior material is poor. For example, when the protective layer is formed of urethane resin, the moldability of the exterior material is good, but the solvent resistance of the outer surface of the exterior material is inferior (sufficient solvent resistance cannot be obtained).

Further, when the protective layer is formed of a fluororesin, the solvent resistance of the exterior material is good, but the adhesion of characters and barcodes to be printed on the surface (outer surface) of the exterior material is insufficient. There is a problem that bleeding is likely to occur in printing and the like, and the printability is poor in this way.

The present invention has been made in view of such a technical background, and is used for an exterior material for a power storage device and a power storage device, which are excellent in moldability, can secure good printability on the surface, and are also excellent in solvent resistance. It is an object of the present invention to provide an outer case and a power storage device.

In order to achieve the above object, the present invention provides the following means.

[1] In an exterior material for a power storage device including a base material layer made of a heat-resistant resin, a sealant layer as an inner layer, and a metal foil layer arranged between the base material layer and the sealant layer.
A protective layer is laminated on the surface of the base material layer opposite to the metal foil layer side.
The protective layer is formed of a polyfunctional isocyanate curing agent containing at least an aliphatic polyfunctional isocyanate compound and a polyester polyol having a hydroxyl group or a carboxyl group and having a number average molecular weight of 5,000 to 50,000 independently at least at both ends. An exterior material for a power storage device, which comprises 40% by mass or more of a polyester resin.

[2] The equivalent ratio [NCO] / [OH + COOH], which is the ratio of the number of moles of the isocyanate group of the polyfunctional isocyanate curing agent to the total number of moles of the hydroxyl group and the number of moles of the carboxyl group, is 0.5 to 5. The exterior material for a power storage device according to the preceding item 1.

[3] The aliphatic polyfunctional isocyanate compound is at least one fat selected from the group consisting of an adduct of trimethylolpropane and an aliphatic diisocyanate compound and an adduct of pentaerythritol and an aliphatic diisocyanate compound. The exterior material for a power storage device according to the above item 1 or 2, which is a group polyfunctional isocyanate compound.

[4] The polyester resin constituting the protective layer is a polyester resin formed of the polyester polyol, the polyfunctional isocyanate curing agent, and a trihydric or higher polyhydric alcohol, according to any one of the above items 1 to 3. The exterior material for the storage device described.

[5] The exterior material for a power storage device according to any one of the above items 1 to 4, wherein the protective layer contains solid fine particles having an average particle size of 1 μm to 10 μm.

[6] The exterior material for a power storage device according to any one of items 1 to 5 above, wherein the protective layer contains a lubricant.

[7] The exterior material for a power storage device according to any one of items 1 to 6 above, wherein a colored layer is arranged between the base material layer and the metal foil layer.

[8] The exterior material for a power storage device according to item 7, wherein the base material layer and the colored layer are laminated and integrated via an easy-adhesive layer.

[9] An exterior case for a power storage device made of a molded body of the exterior material for the power storage device according to any one of the above items 1 to 8.

[10] The main body of the power storage device and
It is provided with an exterior member for a power storage device according to any one of the above items 1 to 8 and / or an exterior member composed of an exterior case for a power storage device according to the above item 9.
A power storage device characterized in that the power storage device main body is covered with the exterior member.

In the invention of [1], the number of protective layers formed by a polyester polyol having a hydroxyl group or a carboxyl group independently at least at both ends and a polyfunctional isocyanate curing agent containing at least an aliphatic polyfunctional isocyanate compound. Since it contains 40% by mass or more of a polyester resin having an average molecular weight of 5,000 to 50,000, it has excellent moldability, can be printed in good condition on the surface of the exterior material (the surface of the protective layer), and is the surface of the protective layer. Is also excellent in solvent resistance.

In the invention of [2], since the equivalent ratio [NCO] / [OH + COOH] is in the range of 0.5 to 5, the surface of the exterior material (the surface of the protective layer) can be printed in a good condition, and the surface of the protective layer can be printed. The solvent resistance of the above can be further improved.

In the invention of [3], since the aliphatic polyfunctional isocyanate compound is the specific aliphatic polyfunctional isocyanate compound, it can be printed in a good state on the surface of the exterior material (the surface of the protective layer) and is protected. The solvent resistance of the surface of the layer can be further improved.

In the invention of [4], since the polyester resin constituting the protective layer is a resin formed of a polyester polyol, a polyfunctional isocyanate curing agent, and a polyhydric alcohol having a trivalent or higher valence, the crosslink density of the resin is high. , The solvent resistance of the surface of the exterior material (the surface of the protective layer) can be further improved.

In the invention of [5], since the protective layer contains solid fine particles having an average particle size of 1 μm to 10 μm, the moldability of the exterior material can be further improved.

In the invention of [6], since the protective layer contains a lubricant, the slipperiness of the surface of the exterior material (the surface of the protective layer) can be improved, and the moldability can be improved.

In the invention of [7], since the colored layer is arranged between the base material layer (heat-resistant resin layer) and the metal foil layer, the color of the colored layer is visible through the base material layer (heat-resistant resin layer). Therefore, the design of the exterior material can be improved. Further, since the colored layer is arranged on the inner side with respect to the base material layer, the colored layer is not scratched or the color is not peeled off, and durability can be ensured.

In the invention of [8], since the base material layer and the colored layer are laminated and integrated via the easy-adhesive layer, the colored layer is sufficiently prevented from peeling off from the base material layer when the exterior material is molded. can.

According to the invention of [9], it is possible to provide an outer case for a power storage device which can ensure good printability on the surface, has excellent solvent resistance, and is molded in a good state.

The invention of [10] provides an exterior material for a power storage device, which can secure good printability on the surface and is also excellent in solvent resistance, and is molded in a good state, and / or a power storage device covered with an outer case. ..

It is sectional drawing which shows one Embodiment of the exterior material for a power storage device which concerns on this invention. It is sectional drawing which shows one Embodiment of the power storage device which concerns on this invention. FIG. 2 is a perspective view showing an exterior material (planar shape) constituting the power storage device, a power storage device main body, and an exterior case (molded body molded into a three-dimensional shape) in a separated state before heat sealing.

An embodiment of the exterior material 1 for a power storage device according to the present invention is shown in FIG. The exterior material 1 for a power storage device of this embodiment is suitably used as a packaging material for a lithium ion secondary battery case, but is not particularly limited to such an application.

In the exterior material 1 for a power storage device, a base material layer (heat resistant resin layer) 2 is laminated and integrated on one surface (upper surface) of the metal foil layer 4 via a first adhesive layer (outer adhesive layer) 5. At the same time, the sealant layer (inner layer) 3 is laminated and integrated on the other surface (lower surface) of the metal foil layer 4 via the second adhesive layer (inner adhesive layer) 6. The protective layer 7 is laminated and integrated on the surface opposite to the metal foil layer 4 side (see FIG. 1).

In the present embodiment, the easy-adhesive layer 8 is laminated on the lower surface of the base material layer (heat-resistant resin layer) 2, the colored layer 9 is laminated on the lower surface of the easy-adhesive layer 8, and the colored layer 9 and the metal leaf are laminated. The layer 4 is adhesively integrated with the layer 4 via the first adhesive layer 5 (see FIG. 1). That is, the colored layer 9 is arranged between the metal foil layer 4 and the base material layer (heat-resistant resin layer) 2. Further, in the present embodiment, the easy-adhesive layer 8 is laminated on the lower surface of the base material layer (heat-resistant resin layer) 2 by the gravure coating method, and the colored layer 9 is laminated on the lower surface of the easy-adhesive layer 8 by printing. ing.

[Protective layer]
In the present invention, the protective layer 7 is a polyester polyol having a hydroxyl group or a carboxyl group and having a number average molecular weight of 5000 to 50,000 independently at least at both ends in the length direction of the main chain, and at least an aliphatic polyfunctional. It is configured to contain 40% by mass or more of a polyester resin formed by a polyfunctional isocyanate curing agent containing an isocyanate compound. Since such a configuration is adopted, the exterior material 1 of the present invention has excellent moldability, can be printed in good condition on the surface of the exterior material (the surface of the protective layer 7), and the surface of the protective layer 7 is resistant to printing. It is also excellent in solvent properties.

As the polyester polyol, for example, a polyester polyol having a hydroxyl group or a carboxyl group independently at least at both ends, which is obtained by mixing a polyhydric alcohol and a polybasic carboxylic acid and performing a polycondensation reaction, is used. However, it is preferable in that the solvent resistance can be further improved. That is, the polyester polyol is preferably a condensed polymer of a polyhydric alcohol and a polybasic carboxylic acid. For example, by blending a polyhydric alcohol and a dicarboxylic acid and performing a polycondensation reaction at 210 ° C. for 20 hours, the above-mentioned "polyester polyol having a hydroxyl group or a carboxyl group independently at least at both ends" can be produced. The polyhydric alcohol is not particularly limited, but for example, ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, 1,6-hexanediol, neopentyl glycol, 1,4-butylene glycol, and trimethylol. Examples thereof include propane, glycerin, 1,9-nanondiol, 3-methyl-1,5-pentanediol and the like. The polybasic carboxylic acid is not particularly limited, and examples thereof include dicarboxylic acids such as aliphatic dicarboxylic acids and aromatic dicarboxylic acids. The aliphatic dicarboxylic acid is not particularly limited, and examples thereof include adipic acid, succinic acid, azelaic acid, suberic acid, sebacic acid, glutaric acid, maleic anhydride, and itaconic anhydride. The aromatic dicarboxylic acid is not particularly limited, but is, for example, isophthalic acid, terephthalic acid, naphthalenedicarboxylic acid, phthalic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, phthalic anhydride, trimellitic acid, and pyromerit. Acids and the like can be mentioned.

As the polyester polyol, a polyester polyol having a number average molecular weight (Mn) of 5,000 to 50,000 is used. If the number average molecular weight is less than 5000, the solvent resistance is inferior, and there arises a problem that the surface of the protective layer becomes cloudy when the solvent adheres to the outer surface of the exterior material. On the other hand, when the number average molecular weight exceeds 50,000, the viscosity becomes high and the viscosity of the coating liquid becomes high, which causes a problem that coating is difficult or coating property is lowered. Among them, the number average molecular weight of the polyester polyol is preferably 8000 to 40,000, and particularly preferably in the range of 10,000 to 30,000. It should be noted that the coatability (coatability) can be sufficiently improved in the range of the number average molecular weight of the polyester polyol in the range of 5000 to 45000.

The number average molecular weight of the polyester polyol is a polystyrene-equivalent value obtained by gel permeation chromatography (GPC). Specifically, for example, KF805L, KF803L, and KF802 (all manufactured by Showa Denko KK) were used as columns, the column temperature was 40 ° C., and tetrahydrofuran (THF) was used as an eluent, and the flow rate was 0.2 mL / min. Detector: Differential refractometer (RI) meter, sample concentration 0.02% by mass, number average molecular weight measured using polystyrene with known molecular weight as a standard sample.

The aliphatic polyfunctional isocyanate compound (hardener) is not particularly limited, but for example, hexamethylene diisocyanate (HMDI), tetramethylene diisocyanate, 1,2-propylene diisocyanate, isophorone diisocyanate (IPDI) and the like. Can be mentioned. As described above, the aliphatic polyfunctional isocyanate compound includes both an acyclic compound and a cyclic (alicyclic) compound. Further, a modified product of an aliphatic polyfunctional isocyanate compound may be used. The modified product of the aliphatic polyfunctional isocyanate compound is not particularly limited, but is, for example, modified with an aliphatic polyfunctional isocyanate compound obtained by an increase reaction such as isocyanurate-forming, polypeptide-forming, and carbodiimidation. The body can be exemplified, specifically, for example, dimer, trimmer, biuret, allophanate of an aliphatic polyfunctional isocyanate compound, carbon dioxide gas and 2,4, obtained from an aliphatic polyfunctional isocyanate compound monomer. Examples thereof include polyisocyanates having a 6-oxadiazine trione ring.

Among them, the aliphatic polyfunctional isocyanate compound is at least selected from the group consisting of an adduct compound of trimethylolpropane and an aliphatic polyfunctional isocyanate compound and an adduct compound of pentaerythritol and an aliphatic polyfunctional isocyanate compound. It is preferable to use one kind of aliphatic polyfunctional isocyanate compound, and further, it is selected from the group consisting of an adduct of trimethylolpropane and an aliphatic diisocyanate compound and an adduct of pentaerythritol and an aliphatic diisocyanate compound. It is particularly preferable to use at least one aliphatic polyfunctional isocyanate compound.

As the curing agent, an aromatic polyfunctional isocyanate compound may be used in combination with the aliphatic polyfunctional isocyanate compound as long as the effect of the present invention is not impaired. The aromatic polyfunctional isocyanate compound is not particularly limited, and examples thereof include tolylene diisocyanate (TDI), diphenylmethane diisocyanate (MDI), and methylene diphenyl diisocyanate.

The content of the aliphatic polyfunctional isocyanate compound in the polyfunctional isocyanate curing agent is preferably set to 30% by mass to 100% by mass, and more preferably 50% by mass to 100% by mass. It is preferable, and it is particularly preferable to set it to 70% by mass to 100% by mass.

The polyester resin constituting the protective layer 7 contains "the polyester polyol", "the polyfunctional isocyanate curing agent containing the aliphatic polyfunctional isocyanate compound", and "a functional group capable of reacting with an isocyanate group" in one molecule. It may be a polyester resin formed by "an aliphatic compound having a plurality of compounds in the above". The aliphatic compound also includes a compound in which atoms such as oxygen, nitrogen, sulfur and chlorine are bonded. The aliphatic compound does not include the polyester polyol and the polyfunctional isocyanate compound. As the aliphatic compound, it is preferable to use a compound having a molecular weight smaller than the number average molecular weight of the polyester polyol. In this case, the curing reaction proceeds rapidly, which has the advantage of improving productivity and an exterior material. Even if the manufacturing procedure of laminating a metal foil and a sealant film (sealant layer) is adopted after forming the protective layer first, the protective layer adheres to the roll of the processing machine and peels off (the surface of the roll). Can be sufficiently prevented from contaminating. Above all, the molecular weight of the above-mentioned "aliphatic compound having a plurality of functional groups capable of reacting with an isocyanate group in one molecule" is more preferably 60 to 9500, and particularly preferably in the range of 100 to 1000.

The functional group capable of reacting with the isocyanate group with respect to the aliphatic compound is not particularly limited, and examples thereof include a hydroxyl group, an amino group, and a carboxyl group. The "aliphatic compound having a plurality of functional groups capable of reacting with an isocyanate group in one molecule" is not particularly limited, but is not particularly limited, and is, for example, a polyhydric alcohol, an aliphatic diamine, or a dicarboxylic acid. Examples include acid. The polyhydric alcohol is an alcohol having two or more alcoholic hydroxyl groups in one molecule. The polyhydric alcohol is not particularly limited, and is, for example, trimethylolethane, trimethylolpropane (TMP), trimethylolbutane, pentaerythritol, 1,2,6-hexanetriol, methylpentanediol, and dimethyl. Examples thereof include butanediol, ethylene glycol, glycerin, carbitol, sorbitol and the like. Above all, it is preferable to use a trihydric or higher polyhydric alcohol.

The content of the aliphatic compound in the polyester resin is preferably 1% by mass to 30% by mass. Among them, 1% by mass to 15% by mass is more preferable, and 3% by mass to 10% by mass is particularly preferable.

The content of the polyester resin in the protective layer 7 is preferably set to 40% by mass to 99.9% by mass. Above all, the content of the polyester resin in the protective layer 7 is more preferably set to 50% by mass to 95% by mass, and particularly preferably set to 60% by mass to 90% by mass.

The protective layer 7 is preferably configured to further contain solid fine particles. By containing the solid fine particles, good slipperiness is imparted to the surface (outer surface of the protective layer 7) of the exterior material 1 for the power storage device, and the moldability of the exterior material 1 for the power storage device can be further improved. The gloss value of the surface (outer surface) of the protective layer 7 is preferably set to 30% or less, and more preferably 1% to 15%, from the viewpoint of improving slipperiness. The gloss value is a value obtained by measuring at a reflection angle of 60 ° with a gloss measuring device "micro-TRI-gloss-s" manufactured by BYK. The solid fine particles are not particularly limited, but are, for example, silica fine particles, alumina fine particles, kaolin fine particles, calcium oxide fine particles, calcium carbonate fine particles, calcium sulfate fine particles, barium sulfate fine particles, calcium silicate fine particles, and silicone resin beads. , Acrylic resin beads, fluororesin beads and the like. Among these, silica fine particles, barium sulfate fine particles, and acrylic resin beads are preferably used. As the solid fine particles, it is preferable to use solid fine particles having an average particle size of 1 μm to 10 μm.

The content of the solid fine particles in the protective layer 7 is preferably set to 0.1% by mass to 60% by mass. When it is 0.1% by mass or more, the slipperiness at the time of molding can be improved, and when it is 60% by mass or less, the suitability for coating process at the time of forming the protective layer can be improved, and the shape retention of the protective layer can be improved. Sufficient sex can be secured. Above all, the content of the solid fine particles in the protective layer 7 is more preferably set to 5% by mass to 45% by mass, and particularly preferably set to 10% by mass to 30% by mass.

The protective layer 7 is preferably configured to contain a lubricant. By containing a lubricant, good slipperiness is imparted, and the moldability of the exterior material 1 for a power storage device can be further improved. The lubricant is not particularly limited, and examples thereof include fatty acid amide, silicone, and wax (polyethylene wax, fluorine-containing polyethylene wax, etc.).

The protective layer 7 may contain an additive. The additive is not particularly limited, and examples thereof include a reaction accelerator and the like. This reaction accelerator is for efficiently proceeding the reaction between the polyester polyol and the polyfunctional isocyanate compound. The reaction accelerator is not particularly limited, and examples thereof include dibutyltin diacetate, dibutyltin dilaurate, dibutyltin dimarate, and tertiary amines (tributylamine, triethanolamine, etc.).

The thickness of the protective layer 7 (thickness after drying) is preferably set to 1 μm to 10 μm. In order to set the thickness of the protective layer 7 in such a thin range, it is preferable that the protective layer 7 is formed of a coating film (a coating film formed by coating).

[Base material layer (heat resistant resin layer)]
The base material layer (heat-resistant resin layer) 2 is a member that mainly plays a role of ensuring good moldability as an exterior material, that is, plays a role of preventing breakage due to necking of a metal foil during molding. be. As the heat-resistant resin constituting the base material layer 2, a heat-resistant resin that does not melt at the heat-sealing temperature when the exterior material 1 is heat-sealed is used. As the heat-resistant resin, it is preferable to use a heat-resistant resin having a melting point of 10 ° C. or higher higher than the melting point of the thermoplastic resin constituting the sealant layer 3, and heat-resistant resin having a melting point of 20 ° C. or higher higher than the melting point of the thermoplastic resin. It is particularly preferable to use a resin.

The base material layer (heat-resistant resin layer) 2 is preferably composed of a heat-resistant resin stretched film having a hot water shrinkage rate of 2% to 20%. When the hot water shrinkage rate is 2% or more, it is possible to sufficiently prevent the colored layer 9 from peeling from the heat-resistant resin layer 2 when used in a slightly harsh environment such as high temperature and humidity. Further, since the hot water shrinkage rate is 20% or less, the colored layer 9 of the exterior material 1 is sufficiently prevented from peeling from the heat-resistant resin layer 2 when molding such as deep drawing molding or overhang molding is performed. can. Above all, as the heat-resistant resin stretched film, it is preferable to use a heat-resistant resin stretched film having a hot water shrinkage rate of 2.5 to 10%. Further, it is more preferable to use a heat-resistant resin stretched film having a hot water shrinkage rate of 3.0% to 6.0%, and further, a heat-resistant resin stretch having a hot water shrinkage rate of 3.5% to 5.0%. It is particularly preferable to use a film.

The "hot water shrinkage rate" is a dimension in the stretching direction of the test piece before and after immersion when the test piece (10 cm × 10 cm) of the heat-resistant resin stretched film 2 is immersed in hot water at 95 ° C. for 30 minutes. It is the rate of change and can be calculated by the following equation.

Hot water shrinkage rate (%) = {(XY) / X} × 100
X: Dimensions in the stretching direction before the dipping treatment Y: Dimensions in the stretching direction after the dipping treatment.

The hot water shrinkage rate when the biaxially stretched film is adopted is the average value of the dimensional change rates in the two stretching directions.

The hot water shrinkage rate of the heat-resistant resin stretched film can be controlled, for example, by adjusting the heat fixing temperature during the stretching process.

The heat-resistant resin stretched film 2 is not particularly limited, and examples thereof include a stretched polyamide film such as a stretched nylon film and a stretched polyester film. Among them, the heat-resistant resin stretched film 2 includes a biaxially stretched polyamide film such as a biaxially stretched nylon film, a biaxially stretched polybutylene terephthalate (PBT) film, a biaxially stretched polyethylene terephthalate (PET) film, or a biaxially stretched polyethylene. It is particularly preferable to use a naphthalate (PEN) film. Further, as the heat-resistant resin stretched film 2, it is preferable to use a heat-resistant resin biaxially stretched film stretched by the simultaneous biaxial stretching method. Further, a heat-resistant resin biaxially stretched film in which the ratio (MD / TD) of the "hot water shrinkage rate in the M direction" to the "hot water shrinkage rate in the T direction" is in the range of 0.9 to 1.1 is used. Is preferable. When the configuration in which the ratio (MD / TD) is in the range of 0.9 to 1.1 is adopted, the exterior material 1 having particularly good moldability can be obtained. The "M direction" means the "machine flow direction", and the "T direction" means the "direction orthogonal to the M direction". The nylon is not particularly limited, and examples thereof include 6 nylon, 6, 6 nylon, and MXD nylon. The heat-resistant resin stretched film layer 2 may be formed of a single layer (single stretched film), or may be a plurality of layers (stretched PET film / stretched) made of, for example, a stretched polyester film / stretched polyamide film. It may be formed of a multi-layer made of a nylon film or the like).

Among them, as the heat-resistant resin stretched film layer 2, a biaxially stretched polyamide film having a shrinkage rate of 2 to 20%, a biaxially stretched polyethylene terephthalate (PEN) film having a shrinkage rate of 2 to 20%, or a shrinkage rate of 2 to 2 to It is preferable to use a 20% biaxially stretched polyethylene terephthalate (PET) film. In this case, the effect of preventing the colored layer 9 from peeling from the heat-resistant resin layer 2 can be further enhanced during molding, sealing, use in a slightly harsh environment such as high temperature and humidity. ..

The thickness of the base material layer (heat-resistant resin layer) 2 is preferably 12 μm to 50 μm. When a polyester film is used, the thickness is preferably 12 μm to 50 μm, and when a nylon film is used, the thickness is preferably 15 μm to 50 μm. By setting it to the above-mentioned suitable lower limit value or more, sufficient strength as an exterior material can be secured, and by setting it to the above-mentioned suitable upper limit value or less, the stress at the time of overhang molding or drawing molding can be reduced and the formability is further improved. be able to.

[Easy adhesive layer]
The easy-adhesion layer 8 may be laminated on the inner surface (the surface on the metal foil layer 4 side) of the base material layer (heat-resistant resin layer) 2. By coating the surface of the heat-resistant resin layer 2, which originally has poor adhesiveness, with a polar resin or the like having excellent adhesiveness and adhesiveness, and laminating the easy-adhesive layer 8, the adhesion and adhesiveness with the colored layer 9 can be further improved. Can be improved. It is preferable that the inner surface of the heat-resistant resin layer 2 (the surface on which the easy-adhesive layer 8 is laminated) is subjected to corona treatment or the like in advance before laminating the easy-adhesive layer 8 to improve the wettability.

The method for forming the easy-adhesion layer 8 is not particularly limited, but for example, an epoxy resin, a urethane resin, an acrylic acid ester resin, a methacrylic acid ester resin, or a polyester resin is formed on the surface of the base material layer (heat resistant resin layer) 2. The easy-adhesive layer 8 can be formed by applying an aqueous emulsion (aqueous emulsion) of one or more kinds of resins selected from the group consisting of polyethyleneimine resins and drying them. The coating method is not particularly limited, and examples thereof include a spray coating method, a gravure roll coating method, a reverse roll coating method, and a lip coating method.

The easy-adhesive layer 8 contains one or more resins selected from the group consisting of epoxy resin, urethane resin, acrylic acid ester resin, methacrylic acid ester resin, polyester resin and polyethyleneimine resin. Is preferable. By adopting such a configuration, the adhesive strength between the heat-resistant resin layer 2 and the colored layer 9 can be further improved, and when the exterior material is formed by deep drawing, overhanging, etc., When the exterior material 9 is sealed for sealing, the colored layer 9 can be sufficiently prevented from peeling from the heat-resistant resin layer 2, and the exterior material 1 is used in a slightly harsh environment such as high temperature and humidity. Even so, it is possible to sufficiently prevent the colored layer 9 from peeling from the heat-resistant resin layer 2.

Above all, it is particularly preferable that the easy-adhesion layer 8 has a structure containing a urethane resin and an epoxy resin, or a structure containing a (meth) acrylic acid ester resin and an epoxy resin. In this case, the adhesive strength between the heat-resistant resin layer 2 and the colored layer 9 can be further improved.

When the former configuration is adopted, the mass ratio of the urethane resin / epoxy resin in the easy-adhesion layer 8 is preferably in the range of 98/2 to 40/60, and in this case, the heat-resistant resin layer 2 and the heat-resistant resin layer 2. The adhesive strength with the colored layer 9 can be further improved. If the content ratio of the urethane resin is larger than the content mass ratio of the urethane resin / epoxy resin (98/2), the degree of cross-linking is insufficient and it becomes difficult to obtain sufficient solvent resistance and adhesive strength, which is not preferable. .. On the other hand, if the urethane resin content ratio is smaller than the urethane resin / epoxy resin content mass ratio (40/60), it takes too much time to complete the crosslinking, which is not preferable. Above all, the content mass ratio of the urethane resin / epoxy resin in the easy-adhesion layer 8 is more preferably in the range of 90/10 to 50/50.

Further, in the case of adopting the latter configuration, the content mass ratio of the (meth) acrylic acid ester resin / epoxy resin in the easy-adhesion layer 8 is preferably in the range of 98/2 to 40/60, and in this case. Can further improve the adhesive strength between the heat-resistant resin layer 2 and the colored layer 9. If the content ratio of the (meth) acrylic acid ester resin is larger than the content mass ratio (98/2) of the (meth) acrylic acid ester resin / epoxy resin, the degree of cross-linking is insufficient, and the solvent resistance and adhesive strength are improved. It is not preferable because it is difficult to obtain enough. On the other hand, if the content ratio of the (meth) acrylic acid ester resin is smaller than the content mass ratio (40/60) of the (meth) acrylic acid ester resin / epoxy resin, it takes too much time to complete the crosslinking. Not preferable. Above all, the content mass ratio of the (meth) acrylic acid ester resin / epoxy resin in the easy-adhesion layer 8 is more preferably in the range of 90/10 to 50/50.

A surfactant such as glycols or an ethylene oxide adduct of glycol may be added to the resin aqueous emulsion (resin-aqueous emulsion) for forming the easy-adhesion layer 8. In this case, the resin aqueous emulsion is added. Since a sufficient defoaming effect can be obtained in the emulsion, the easy-adhesive layer 8 having excellent surface smoothness can be formed. The surfactant is preferably contained in the resin aqueous emulsion in an amount of 0.01% by mass to 2.0% by mass.

Further, it is preferable that the resin aqueous emulsion (resin-water emulsion) for forming the easy-adhesion layer 8 contains inorganic fine particles such as silica and colloidal silica, and in this case, a blocking prevention effect is obtained. Can be done. It is preferable to add 0.1 part by mass to 10 parts by mass of the inorganic fine particles with respect to 100 parts by mass of the resin content.

The amount of the easy-adhesion layer 8 formed (the amount of solid content after drying) is preferably in the range of 0.01 g / m ² to 0.5 g / m ² . When it is 0.01 g / m ² or more, the heat-resistant resin stretched film layer 2 and the colored ink layer 9 can be sufficiently adhered, and when it is 0.5 g / m ² or less, the cost can be reduced and it is economical. Is.

The content of the resin in the easy-adhesion layer (after drying) 8 is preferably 88% by mass to 99.9% by mass.

[Colored layer]
A configuration in which the colored layer 9 is arranged between the base material layer 2 and the metal foil layer 4 may be adopted. By adopting such a configuration, it is possible to impart a color (including an achromatic color) or a design to the outer surface side of the exterior material 1.

The colored layer 9 is not particularly limited, and examples thereof include a black ink layer, a white ink layer, a gray ink layer, a red ink layer, a blue ink layer, a green ink layer, and a yellow ink layer.

The black ink layer 9 will be described. The black ink layer 10 is usually formed of a composition containing carbon black.

Above all, the black ink layer 9 is preferably configured to contain carbon black, diamine, polyol and a curing agent, but is not particularly limited to such a configuration.

In the black ink layer (ink layer after drying) 9, the content of carbon black is 15% by mass to 60% by mass, and the total content of the diamine, the polyol and the curing agent is 40% by mass to 85% by mass. Is preferable. Above all, the content of carbon black is particularly preferably 20% by mass to 50% by mass.

If the content of carbon black is less than 15% by mass, the metallic luster due to the metal foil layer 4 remains, the profound feeling is impaired, and partial color unevenness is likely to occur during molding, which is not preferable. On the other hand, when the content of carbon black exceeds 60% by mass, the black ink layer 9 becomes hard and brittle, so that the adhesive force to the metal foil layer 4 decreases, and the metal foil layer 4 and the black ink layer 9 are formed during molding. It is not preferable because it may cause peeling between the two.

The black ink layer 9 preferably contains 2 parts by mass to 20 parts by mass of the curing agent per 100 parts by mass of the total amount of the carbon black, the diamine and the polyol. If the amount of the curing agent is less than 2 parts by mass, peeling is likely to occur between the metal foil layer 4 and the black ink layer 9 during molding, and if the amount of the curing agent exceeds 20 parts by mass, the exterior material 1 in the wound state is unwound ( Blocking occurs during unwinding), and problems such as transfer and adhesion to the outer surface of the heat-resistant resin layer 2 and the sealant layer (thermoplastic resin layer) 3 are likely to occur, which is not preferable.

As the carbon black, it is preferable to use one having an average particle diameter of 0.2 μm to 5 μm.

The diamine is not particularly limited, and examples thereof include ethylenediamine, dimerdiamine, 2-hydroxyethylethylenediamine, 2-hydroxyethylpropylenediamine, dicyclohexylmethanediamine, and 2-hydroxyethylpropylenediamine. Among them, as the diamine, it is preferable to use one or more diamines selected from the group consisting of ethylenediamine, dimerdiamine, 2-hydroxyethylethylenediamine, 2-hydroxyethylpropylenediamine and dicyclohexylmethanediamine.

The diamine has a faster reaction rate with a curing agent (isocyanate or the like) than a polyol, and can be cured in a short time. That is, the diamine reacts with the curing agent together with the polyol to promote cross-linking curing of the ink composition.

The polyol is not particularly limited, but it is preferable to use one or more of the polyols selected from the group consisting of polyurethane-based polyols, polyester-based polyols and polyether-based polyols.

The number average molecular weight of the polyol is preferably in the range of 1000 to 8000. When it is 1000 or more, the adhesive strength after curing can be increased, and when it is 8000 or less, the reaction rate with the curing agent can be increased.

The curing agent is not particularly limited, and examples thereof include isocyanate compounds. As the isocyanate compound, for example, various aromatic, aliphatic, and alicyclic isocyanate compounds can be used. Specific examples thereof include toluene diisocyanate (TDI), diphenylmethane diisocyanate, hexamethylene diisocyanate (HDI), isophorone diisocyanate and the like.

The colored ink layer (excluding the black ink layer) 9 will be described. The colored ink layer (excluding the black ink layer) 9 contains a two-component curable polyester urethane resin binder containing a polyester resin as a main agent and a polyfunctional isocyanate compound as a curing agent, and a colored pigment containing an inorganic pigment. It is preferably composed of a cured film of the colored ink composition.

As the coloring pigment, a configuration containing at least an inorganic pigment is adopted. Examples of the coloring pigment include azo pigments, phthalocyanine pigments, condensed polycyclic pigments, and the like, in addition to the inorganic pigments. The inorganic pigment is not particularly limited, and examples thereof include carbon black, calcium carbonate, titanium oxide, zinc oxide, iron oxide, and aluminum powder. As the inorganic pigment, those having an average particle size of 0.1 μm to 5 μm are preferable, and those having an average particle size of 0.5 μm to 2.5 μm are particularly preferable. When dispersing the colored pigment, it is preferable to disperse the colored pigment using a pigment disperser. When dispersing the colored pigment, a pigment dispersant such as a surfactant can also be used.

It is preferable that 50% by mass or more of the coloring pigment is composed of the inorganic pigment. In this case, it is possible to form the colored ink layer 9 having a specific color tone, which can sufficiently obtain the hiding power for hiding the metal foil layer 4 and sufficiently impart a profound feeling and a high-class feeling. Above all, it is more preferable that 60% by mass or more of the coloring pigment is composed of the inorganic pigment.

The thickness (after drying) of the colored layer 9 is preferably 1 μm to 4 μm. When the thickness is 1 μm or more, the color tone of the colored layer 9 does not remain transparent, and the color and gloss of the metal foil layer 4 can be sufficiently concealed. Further, when the thickness is 4 μm or less, it is possible to sufficiently prevent the colored layer 9 from being partially cracked during molding.

The colored layer 9 is not particularly limited, but for example,
1) Ink composition containing carbon black, diamine, polyol, curing agent and organic solvent or 2) Two-component curable polyester urethane resin binder with polyester resin as main agent and polyfunctional isocyanate compound as curing agent, and inorganic It can be formed by printing (applying) a colored pigment containing a pigment and a colored ink composition containing the pigment on the surface of the easy-adhesion layer 8 on the lower surface of the heat-resistant resin layer 2 by a gravure printing method or the like. The organic solvent is not particularly limited, and examples thereof include toluene and the like.

The method for forming the colored layer 9 is not particularly limited, and examples thereof include a gravure printing method, a reverse roll coating method, and a lip roll coating method.

[Sealant layer (inner layer)]
The sealant layer (inner layer) 3 is formed of a thermoplastic resin layer. The sealant layer (inner layer) 3 is provided with excellent chemical resistance against a highly corrosive electrolytic solution used in a lithium ion secondary battery or the like, and also imparts heat sealability to the exterior material 1. It plays a role.

The thermoplastic resin layer 3 is not particularly limited, but is preferably a thermoplastic resin unstretched film layer. The thermoplastic resin unstretched film layer 3 is not particularly limited, but is at least one thermoplastic selected from the group consisting of polyethylene, polypropylene, olefin-based copolymers, acid-modified products thereof, and ionomers. It is preferably composed of an unstretched film made of a resin.

Among them, the thermoplastic resin layer 3 is a random copolymer containing propylene as a copolymerization component and other copolymerization components other than propylene on both sides of an intermediate layer containing an elastomer-modified olefin resin. A three-layer structure in which the layers are laminated is more preferable in that sufficient insulation can be ensured during heat sealing.

The elastomer-modified olefin resin (polypropylene block copolymer) constituting the intermediate layer is preferably made of an elastomer-modified homopolypropylene and / or an elastomer-modified random copolymer. The elastomer-modified random copolymer is an elastomer-modified random copolymer containing "propylene" and "other copolymerization components other than propylene" as copolymerization components, and is the above-mentioned "other copolymerization other than propylene". The "component" is not particularly limited, and examples thereof include olefin components such as ethylene, 1-butene, 1-hexene, 1-pentene, 4-methyl-1-pentene, and butadiene and the like. The elastomer is not particularly limited, but it is preferable to use an olefin-based thermoplastic elastomer. The olefin-based thermoplastic elastomer is not particularly limited, and examples thereof include EPR (ethylene propylene rubber), propylene-butene elastomer, propylene-butene-ethylene elastomer, and EPDM (ethylene-propylene-diene rubber). Above all, it is preferable to use EPR (ethylene propylene rubber). Regarding the elastomer-modified olefin-based resin, as an embodiment of "elastomer-modified", an elastomer may be graft-polymerized, or the elastomer may be added to an olefin-based resin (homopolypropylene and / and the random copolymer). It may be one, or it may be another modification mode.

The random copolymer (layer) is a random copolymer containing "propylene" and "other copolymerization components other than propylene" as copolymerization components. The "other copolymerization component other than propylene" is not particularly limited with respect to the random copolymer, and for example, ethylene, 1-butene, 1-hexene, 1-pentene, and 4methyl-1 are not particularly limited. -In addition to olefin components such as penten, butadiene and the like can be mentioned.

The thickness of the thermoplastic resin layer 3 is preferably set to 20 μm to 80 μm. By setting it to 20 μm or more, the occurrence of pinholes can be sufficiently prevented, and by setting it to 80 μm or less, the amount of resin used can be reduced and the cost can be reduced. Above all, it is particularly preferable that the thickness of the thermoplastic resin layer 3 is set to 30 μm to 50 μm. The thermoplastic resin layer 3 may be a single layer or a plurality of layers.

[Metal leaf layer]
The metal foil layer 4 plays a role of imparting a gas barrier property to prevent the intrusion of oxygen and moisture into the exterior material 1. The metal foil layer 4 is not particularly limited, and examples thereof include aluminum foil, copper foil, nickel foil, stainless steel foil, and the like, and aluminum foil is generally used. As the aluminum foil, A8079HO and A8021HO specified in JIS H4160-2006 are preferable. The thickness of the metal foil layer 4 is preferably 20 μm to 100 μm. When it is 20 μm or more, it is possible to prevent the occurrence of pinholes during rolling when manufacturing a metal foil, and when it is 100 μm or less, it is possible to reduce the stress during overhang molding and draw forming and improve the formability. can.

It is preferable that at least the inner surface 4a (the surface on the inner adhesive layer 6 side) of the metal foil layer 4 is subjected to chemical conversion treatment. By performing such a chemical conversion treatment, it is possible to sufficiently prevent corrosion of the surface of the metal foil due to the contents (electrolyte of the battery, food, pharmaceuticals, etc.). For example, the metal foil is subjected to chemical conversion treatment by performing the following treatment. That is, for example, on the surface of the metal leaf that has been degreased,
1) Aqueous solution consisting of a mixture of a metal salt of phosphoric acid, chromium acid and fluoride 2) An aqueous solution consisting of a mixture of a metal salt of phosphoric acid, chromium acid, a metal fluoride and a non-metal salt of fluoride 3) Acrylic resin and / and phenol A chemical conversion treatment is carried out by applying any of an aqueous solution consisting of a mixture of a system resin, phosphoric acid, chromium acid and a fluoride metal salt, and then drying.

[Outer adhesive layer (first adhesive layer)]
The outer adhesive layer 5 is not particularly limited, and examples thereof include an adhesive layer formed of a two-component curable adhesive. The two-component curable adhesive is not particularly limited, and examples thereof include a two-component curable urethane-based adhesive and a two-component curable polyester urethane-based adhesive. The two-component curable urethane-based adhesive is not particularly limited, and examples thereof include a two-component curable urethane-based adhesive containing a polyol component and an isocyanate component. This two-component curable urethane-based adhesive is particularly preferably used when adhering by the dry laminating method. The polyol component is not particularly limited, and examples thereof include polyester polyols and polyether polyols. The isocyanate component is not particularly limited, and examples thereof include diisocyanates such as TDI (toluene diisocyanate), HMDI (hexamethylene diisocyanate), and MDI (methylenebis (4,1-phenylene) diisocyanate). .. The thickness of the outer adhesive layer 5 is preferably set to 2 μm to 5 μm, and particularly preferably 3 μm to 4 μm. An inorganic or organic anti-blocking agent or an amide-based slip agent may be added to the outer adhesive layer 5.

In the outer adhesive layer 5, for example, an adhesive such as the two-component curable adhesive can be easily adhered to the "upper surface of the metal foil layer 4" and / or to the lower surface of the heat-resistant resin layer 2. It is formed by being applied to the lower surface of the colored layer 9 laminated via the layer 8 by a method such as a gravure coating method. The method for forming the outer adhesive layer 5 is merely an example thereof, and is not particularly limited to such a forming method.

[Inner adhesive layer (second adhesive layer)]
The inner adhesive layer 6 adheres the metal foil layer 4 and the sealant layer 3. The inner adhesive layer 5 has at least the metal foil layer 4 and the sealant in order to prevent deterioration of the laminate strength over time due to the influence of an electrolytic solution or the like. It is preferable to use an adhesive resin having good adhesiveness to both the layer 3 and the layer 3. The specific type of the resin is not particularly limited, but for example, dicarboxylic acids such as maleic acid, fumaric acid, itaconic acid, and mesaconic acid, maleic anhydride, fumaric acid anhydride, itaconic acid anhydride, and mesacon anhydride. Examples thereof include a resin obtained by graft-adding modification or copolymerizing a carboxyl group-containing monomer such as a dicarboxylic acid anhydride such as an acid, acrylic acid, methacrylic acid, crotonic acid, and itaconic acid to polypropylene. Among these, it is preferable to use a resin graft-added and modified with maleic anhydride, acrylic acid or methacrylic acid, and a maleic anhydride-modified polyolefin resin is particularly preferable. The method for producing such a resin is not particularly limited, but for example, polypropylene is a solution method in which polypropylene is dissolved in an organic solvent and this is reacted with an acid (maleic anhydride or the like) in the presence of a radical generator. Can be exemplified by a melting method in which the above is heated and melted, and this is reacted with an acid (maleic anhydride or the like) in the presence of a radical generator.

Further, the inner adhesive layer 6 contains a polyolefin resin having a carboxyl group in the chemical structure and a polyfunctional isocyanate compound from the viewpoint of increasing the service life of the exterior material by sufficiently ensuring the electrolytic solution resistance. It is particularly preferable that the adhesive composition is composed of the above. In the inner adhesive layer 6, for example, an adhesive liquid containing a polyolefin resin having a carboxyl group, a polyfunctional isocyanate compound, and an organic solvent is applied to the metal foil layer 4 and / and the sealant layer 3. It can be formed by drying it.

The polyolefin resin having a carboxyl group (hereinafter, may be referred to as “carboxyl group-containing polyolefin resin”) is not particularly limited, but for example, an ethylenically unsaturated carboxylic acid or an acid anhydride thereof is added to the polyolefin. Examples thereof include a modified polyolefin resin obtained by graft-polymerizing the above, a copolymer resin of an olefin monomer and an ethylenically unsaturated carboxylic acid, and the like. The polyolefin is not particularly limited, and examples thereof include homopolymers of olefin monomers such as ethylene, propylene, and butene, and copolymers of these olefin monomers. The ethylenically unsaturated carboxylic acid is not particularly limited, and examples thereof include acrylic acid, methacrylic acid, maleic acid, fumaric acid, crotonic acid, and itaconic acid. Only one kind of these ethylenically unsaturated carboxylic acids may be used, or two or more kinds thereof may be used in combination. Further, as the carboxyl group-containing polyolefin resin, one that is soluble in an organic solvent is preferably used.

Among them, as the carboxyl group-containing polyolefin resin, a modified polyolefin resin obtained by graft-polymerizing an ethylenically unsaturated carboxylic acid or an acid anhydride thereof with a homopolymer of propylene or a copolymer of propylene and ethylene is used. preferable. The carboxyl group-containing polyolefin resin may have a single composition or may be a mixture of two or more kinds having different melting points.

The polyfunctional isocyanate compound reacts with the carboxyl group-containing polyolefin resin and acts as a curing agent for curing the adhesive composition. The polyfunctional isocyanate compound is not particularly limited, but is, for example, tolylene diisocyanate, diphenylmethane diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, or isocyanurate-modified products, buretto-modified products, or the above-mentioned diisocyanates. Examples thereof include a modified product obtained by adduct-modifying the compound with a polyhydric alcohol such as trimethylol propane. The polyfunctional isocyanate compound may be used alone or in combination of two or more. Further, as the polyfunctional isocyanate compound, a polyfunctional isocyanate compound that dissolves in an organic solvent is preferably used.

The organic solvent is not particularly limited as long as it can dissolve or disperse the carboxyl group-containing polyolefin resin. Among these, an organic solvent capable of dissolving the carboxyl group-containing polyolefin resin is preferably used. Further, as the organic solvent, an organic solvent that can be easily removed by volatilizing the organic solvent from the adhesive liquid by heating or the like is preferably used. The organic solvent that can dissolve the carboxyl group-containing polyolefin resin and can be easily volatilized and removed by heating or the like is not particularly limited, but is not particularly limited, and is, for example, an aromatic organic solvent such as toluene or xylene. Examples thereof include a solvent, an aliphatic organic solvent such as n-hexane, an alicyclic organic solvent such as cyclohexane and methylcyclohexane (MCH), and a ketone organic solvent such as methylethylketone (MEK). Only one kind of these organic solvents may be used, or two or more kinds thereof may be used in combination.

In the adhesive liquid or the adhesive resin composition, the equivalent ratio [NCO] / [OH] of the isocyanate group of the polyfunctional isocyanate compound to the hydroxyl group constituting the carboxyl group of the carboxyl group-containing polyolefin resin is 0.5 to 10. It is preferably set to 0.0. If it is set in such a range, it is possible to obtain an adhesive composition having excellent initial adhesive performance, and the adhesive strength between the metal foil layer 4 and the sealant layer 3 by the electrolytic solution of the battery with time. The target deterioration can be sufficiently suppressed for a longer period of time, and the electrolytic solution resistance performance can be further improved. The equivalent ratio [NCO] / [OH] is more preferably set to 1.0 to 9.0, and particularly preferably 1.0 to 6.0.

If necessary, the adhesive liquid or the adhesive composition may contain additives such as a reaction accelerator, a tackifier, and a plasticizer.

The thickness of the inner adhesive layer 6 is preferably set to 1 μm to 10 μm. When it is 1 μm or more, sufficient adhesive strength can be obtained, and when it is 10 μm or less, the water vapor barrier property can be improved.

In the above embodiment, the structure in which the easy-adhesive layer 8, the colored layer 9, the first adhesive layer 5, and the second adhesive layer 6 are provided is adopted, but all of these layers are indispensable configurations. It is also possible to adopt a configuration in which these are not provided instead of the layers.

By molding the exterior material 1 for a power storage device of the present invention (deep drawing molding, overhang molding, etc.), the exterior case 10 for a power storage device can be obtained (see FIG. 3). The exterior material 1 of the present invention can be used as it is without being subjected to molding (see FIG. 3).

FIG. 2 shows an embodiment of the power storage device 30 configured by using the exterior material 1 of the present invention. The power storage device 30 is a lithium ion secondary battery. In the present embodiment, as shown in FIGS. 2 and 3, the exterior member 15 is composed of the exterior case 10 obtained by molding the exterior material 1 and the flat exterior material 1 that has not been subjected to molding. ing. The storage device main body (electrochemical element, etc.) 31 having a substantially rectangular parallelepiped shape is housed in the storage recess of the exterior case 10 obtained by molding the exterior material 1 of the present invention. The exterior material 1 of the present invention is arranged on the inner layer 3 side (lower side) without being molded, and the peripheral portion of the inner layer 3 of the planar exterior material 1 and the exterior. The power storage device 30 of the present invention is configured by sealing and sealing the inner layer 3 of the flange portion (sealing peripheral portion) 29 of the case 10 by heat sealing (see FIGS. 2 and 3). ). The inner surface of the accommodating recess of the exterior case 10 is an inner layer (sealant layer) 3, and the outer surface of the accommodating recess is a protective layer 7 (see FIG. 3).

In FIG. 2, 39 is a heat-sealed portion in which the peripheral edge portion of the exterior material 1 and the flange portion (sealing peripheral edge portion) 29 of the exterior case 10 are joined (fused). In the power storage device 30, the tip of the tab lead connected to the power storage device main body 31 is led out to the outside of the exterior member 15, but the illustration is omitted.

The power storage device main body 31 is not particularly limited, and examples thereof include a battery main body, a capacitor main body, and a capacitor main body.

The width of the heat seal portion 39 is preferably set to 0.5 mm or more. By setting the thickness to 0.5 mm or more, sealing can be reliably performed. Above all, the width of the heat seal portion 39 is preferably set to 3 mm to 15 mm.

In the above embodiment, the exterior member 15 is composed of an exterior case 10 obtained by molding the exterior material 1 and a flat exterior material 1 (see FIGS. 2 and 3), but in particular, the exterior member 15. The combination is not limited to the above, and the exterior member 15 may be composed of a pair of exterior materials 1 or a pair of exterior cases 10.

Next, specific examples of the present invention will be described, but the present invention is not particularly limited to those of these examples.

<Example 1>
A main agent was obtained by blending 50 parts by mass of carbon black having an average particle diameter of 0.8 μm, 5 parts by mass of ethylenediamine, and 45 parts by mass of a polyester-based polyol (number average molecular weight: 2500). An ink composition was obtained by blending 3 parts by mass of tolylene diisocyanate (TDI), which is a curing agent, with 100 parts by mass of the main agent, and further adding 50 parts by mass of toluene and stirring well.

In addition, 70 parts by mass of "Takelac W-6010" manufactured by Mitsui Chemicals Co., Ltd. as a water-based urethane resin, 30 parts by mass of "Denacol EX-521" manufactured by Nagase Chemtech Co., Ltd. as a water-based epoxy resin, and Nissan Chemical Industry Co., Ltd. as a blocking inhibitor. 5 parts by mass of colloidal silica "Snowtex ST-C" (average particle size 10 nm to 20 nm) manufactured by M. An adhesive composition for use was obtained.

Next, a biaxially stretched nylon (6 nylon) film (heat resistant resin stretched film layer, MD / TD =) obtained by stretching by the simultaneous biaxial stretching method and having a thickness of 15 μm and a hot water shrinkage rate of 4.0%. 0.95) The adhesive composition for forming an easy-adhesion layer is applied to one surface of 2 by a gravure roll coating method, dried, and then allowed to stand in an environment of 40 ° C. for 1 day to proceed with a curing reaction. Then, the easy-adhesive layer 8 having a forming amount of 0.1 g / m ² was formed.

Next, the ink composition was printed (applied) on the surface of the easy-adhesion layer 8 of the biaxially stretched nylon film 2 by a gravure printing method, and then left to stand in an environment of 40 ° C. for 1 day to dry the ink. The cross-linking reaction was allowed to proceed to form a colored layer (black ink layer) 9 having a thickness of 3 μm to obtain a first laminated body.

Further, 55 parts by mass of polyester (number average molecular weight: 5300) having hydroxyl groups at both ends in the length direction of the main chain on the biaxially stretched nylon film 2 of the first laminated body (on the unlaminated surface). 13 parts by mass of adduct body (referred to as "adduct body A" in the table) of trimethylolpropane and hexamethylene diisocyanate, 2 parts by mass of powdered silica having an average particle size of 2 μm, and 20 parts by mass of barium sulfate having an average particle size of 2 μm. After applying a protective layer forming composition consisting of 5 parts by mass of acrylic resin beads having an average particle size of 7 μm, 5 parts by mass of polyethylene wax and 100 parts by mass of a solvent (50 parts by mass of methyl ethyl ketone: 50 parts by mass of toluene), 60 ° C. The reaction was allowed to proceed by allowing it to stand in an environment for 3 days to form a protective layer 7 having a thickness of 2 μm, and a second laminated body was obtained. The equivalent ratio [NCO] / [OH + COOH] in the protective layer forming composition was 2.9.

On the other hand, a chemical conversion treatment solution composed of polyacrylic acid, phosphoric acid, a trivalent chromium compound, water, and alcohol was applied to both sides of an aluminum foil 4 having a thickness of 35 μm, and dried at 180 ° C., and the amount of chromium adhered was 5 mg. It was set to / m ² .

Next, the second laminate was bonded to one surface of the chemical-treated aluminum foil 4 via a polyester-based polyurethane adhesive 5 on the colored layer (black ink layer) 9 side, and then the aluminum foil 4 was formed. An unstretched polypropylene film (thermoplastic resin layer) 3 having a thickness of 30 μm was attached to the other surface via a maleic anhydride-modified polypropylene adhesive 6, and then left to stand in an environment of 40 ° C. for 5 days. The exterior material 1 for a power storage device shown in 1 was obtained.

<Example 2>
In the protective layer forming composition, "55 parts by mass of polyester (number average molecular weight: 5300) having hydroxyl groups at both ends in the length direction of the main chain, 13 parts by mass of an adduct body of trimethylolpropane and hexamethylene diisocyanate. Is changed to "63 parts by mass of polyester (number average molecular weight: 9800) having hydroxyl groups at both ends in the length direction of the main chain, 5 parts by mass of an adduct of trimethylolpropane and hexamethylene diisocyanate", and the equivalent ratio. The exterior material 1 for a power storage device shown in FIG. 1 was obtained in the same manner as in Example 1 except that the composition for forming a protective layer having [NCO] / [OH + COOH] of 1.8 was used.

<Example 3>
FIG. 1 is the same as in Example 2 except that the composition for forming a protective layer of Example 2 is further contained with erucic acid amide at a concentration of 5000 ppm as the composition for forming a protective layer. The exterior material 1 for a power storage device shown in 1 above was obtained.

<Example 4>
In the composition for forming a protective layer, "55 parts by mass of polyester (number average molecular weight: 5300) having hydroxyl groups at both ends in the length direction of the main chain, 13 parts by mass of an adduct of trimethylolpropane and hexamethylene diisocyanate". Was changed to "65 parts by mass of polyester (number average molecular weight: 14500) having hydroxyl groups at both ends in the length direction of the main chain, 3 parts by mass of an adduct of trimethylolpropane and hexamethylene diisocyanate", and the equivalent ratio [ The exterior material 1 for a power storage device shown in FIG. 1 was obtained in the same manner as in Example 1 except that the composition for forming a protective layer having NCO] / [OH + COOH] of 1.6 was used.

<Example 5>
In the composition for forming a protective layer, "3 parts by mass of an adduct body of trimethylolpropane and hexamethylene diisocyanate" is replaced with "1.5 parts by mass of an adduct body of trimethylolpropane and hexamethylene diisocyanate, and trimethylolpropane and tolylene diisocyanate." The exterior material 1 for a power storage device shown in FIG. 1 was obtained in the same manner as in Example 4 except that the adduct body with (TDI) was changed to 1.5 parts by mass.

<Example 6>
In the composition for forming a protective layer, "55 parts by mass of polyester (number average molecular weight: 5300) having hydroxyl groups at both ends in the length direction of the main chain, 13 parts by mass of an adduct of trimethylolpropane and hexamethylene diisocyanate". Was changed to "65 parts by mass of polyester (number average molecular weight: 14500) having hydroxyl groups at both ends in the length direction of the main chain, 3 parts by mass of an adduct of pentaerythritol and hexamethylene diisocyanate", and the equivalent ratio [NCO ] / [OH + COOH] obtained the exterior material 1 for a power storage device shown in FIG. 1 in the same manner as in Example 1 except that the composition for forming a protective layer having 1.7 was used.

<Example 7>
Instead of polyester having hydroxyl groups at both ends in the length direction of the main chain (number average molecular weight: 14500), polyester having hydroxyl groups at both ends in the length direction of the main chain (number average molecular weight: 19600) is used. The exterior material 1 for the power storage device shown in FIG. 1 was obtained in the same manner as in Example 4.

<Example 8>
Instead of polyester having hydroxyl groups at both ends in the length direction of the main chain (number average molecular weight: 14500), polyester having hydroxyl groups at both ends in the length direction of the main chain (number average molecular weight: 28500) is used. The exterior material 1 for the power storage device shown in FIG. 1 was obtained in the same manner as in Example 4.

<Example 9>
Instead of polyester having hydroxyl groups at both ends in the length direction of the main chain (number average molecular weight: 5300), polyester having hydroxyl groups at both ends in the length direction of the main chain (number average molecular weight: 49000) is used. The exterior material 1 for the power storage device shown in FIG. 1 was obtained in the same manner as in Example 1.

<Example 10>
Instead of polyester having hydroxyl groups at both ends in the length direction of the main chain (number average molecular weight: 9800), polyester having carboxyl groups at both ends in the length direction of the main chain (number average molecular weight: 9800) is used. The exterior material 1 for the power storage device shown in FIG. 1 was obtained in the same manner as in Example 3 except that it was used.

<Example 11>
As a composition for forming a protective layer, 57 parts by mass of polyester (number average molecular weight: 9800) having hydroxyl groups at both ends in the length direction of the main chain, 10 parts by mass of an adduct of trimethylolpropane and hexamethylene diisocyanate, and a bird. 1 part by mass of trimethylolpropane (polyhydric alcohol), 2 parts by mass of powdered silica having an average particle size of 2 μm, 20 parts by mass of barium sulfate having an average particle size of 2 μm, 5 parts by mass of acrylic resin beads having an average particle size of 7 μm, and 5 parts by mass of wax. The exterior material 1 for a power storage device shown in FIG. 1 was obtained in the same manner as in Example 2 except that the composition for forming a protective layer composed of parts was used.

<Example 12>
As a composition for forming a protective layer, 57 parts by mass of polyester (number average molecular weight: 9800) having hydroxyl groups at both ends in the length direction of the main chain, 10 parts by mass of an adduct of trimethylolpropane and hexamethylene diisocyanate, and penta. 1 part by mass of erythritol (polyhydric alcohol), 2 parts by mass of powdered silica with an average particle size of 2 μm, 20 parts by mass of barium sulfate with an average particle size of 2 μm, 5 parts by mass of acrylic resin beads with an average particle size of 7 μm, and 5 parts by mass of wax. The exterior material 1 for a power storage device shown in FIG. 1 was obtained in the same manner as in Example 2 except that the composition for forming a protective layer made of the above was used.

<Example 13>
As a composition for forming a protective layer, 57 parts by mass of polyester (number average molecular weight: 9800) having hydroxyl groups at both ends in the length direction of the main chain, 10 parts by mass of an adduct of trimethylolpropane and hexamethylene diisocyanate, and glycerin. From 1 part by mass of (polyhydric alcohol), 2 parts by mass of powdered silica having an average particle size of 2 μm, 20 parts by mass of barium sulfate having an average particle size of 2 μm, 5 parts by mass of acrylic resin beads having an average particle size of 7 μm, and 5 parts by mass of wax. The exterior material 1 for a power storage device shown in FIG. 1 was obtained in the same manner as in Example 2 except that the composition for forming a protective layer was used.

<Example 14>
In the composition for forming a protective layer, "55 parts by mass of polyester (number average molecular weight: 5300) having hydroxyl groups at both ends in the length direction of the main chain, 13 parts by mass of an adduct of trimethylolpropane and hexamethylene diisocyanate". "Has four hydroxyl groups including the hydroxyl groups at both ends in the length direction of the main chain (having hydroxyl groups at both ends in the length direction of the main chain, and two hydroxyl groups in the middle of the chain of the main chain. Protective layer with an equivalent ratio of [NCO] / [OH + COOH] of 0.8 The exterior material 1 for the power storage device shown in FIG. 1 was obtained in the same manner as in Example 1 except that the composition for forming was used.

<Example 15>
In the composition for forming a protective layer, "55 parts by mass of polyester (number average molecular weight: 5300) having hydroxyl groups at both ends in the length direction of the main chain, 13 parts by mass of an adduct of trimethylolpropane and hexamethylene diisocyanate". "Has four hydroxyl groups including the hydroxyl groups at both ends in the length direction of the main chain (having hydroxyl groups at both ends in the length direction of the main chain, and two hydroxyl groups in the middle of the chain of the main chain. Protective layer with an equivalent ratio of [NCO] / [OH + COOH] of 0.9 The exterior material 1 for the power storage device shown in FIG. 1 was obtained in the same manner as in Example 1 except that the composition for forming was used.

<Comparative Example 1>
As a composition for forming a protective layer, 65 parts by mass of a fluorine-containing polyol (number average molecular weight: 15,000), 3 parts by mass of an adduct of trimethylolpropane and hexamethylene diisocyanate, 2 parts by mass of powdered silica having an average particle size of 2 μm, average. The figure is the same as in Example 1 except that a protective layer forming composition consisting of 20 parts by mass of barium sulfate having a particle size of 2 μm, 5 parts by mass of acrylic resin beads having an average particle size of 7 μm, and 5 parts by mass of wax was used. The exterior material 1 for a power storage device shown in 1 was obtained.

<Comparative Example 2>
As a composition for forming a protective layer, 53 parts by mass of a polyurethane polyol (number average molecular weight: 5400), 15 parts by mass of an adduct of trimethylolpropane and hexamethylene diisocyanate, 2 parts by mass of powdered silica having an average particle size of 2 μm, and average grains. FIG. 1 is the same as in Example 1 except that a protective layer forming composition consisting of 20 parts by mass of barium sulfate having a diameter of 2 μm, 5 parts by mass of acrylic resin beads having an average particle size of 7 μm, and 5 parts by mass of wax was used. The exterior material 1 for a power storage device shown in 1 above was obtained.

<Comparative Example 3>
As a composition for forming a protective layer, 53 parts by mass of an acrylic polyol (number average molecular weight: 3400), 15 parts by mass of an adduct of trimethylolpropane and hexamethylene diisocyanate, 2 parts by mass of powdered silica having an average particle size of 2 μm, average. The figure is the same as in Example 1 except that a protective layer forming composition consisting of 20 parts by mass of barium sulfate having a particle size of 2 μm, 5 parts by mass of acrylic resin beads having an average particle size of 7 μm, and 5 parts by mass of wax was used. The exterior material 1 for a power storage device shown in 1 was obtained.

<Comparative Example 4>
In the composition for forming a protective layer, "55 parts by mass of polyester (number average molecular weight: 5300) having hydroxyl groups at both ends in the length direction of the main chain, 13 parts by mass of an adduct of trimethylolpropane and hexamethylene diisocyanate". Was changed to "53 parts by mass of polyester (number average molecular weight: 3900) having hydroxyl groups at both ends in the length direction of the main chain, 15 parts by mass of an adduct of pentaerythritol and hexamethylene diisocyanate", and the equivalent ratio [NCO ] / [OH + COOH] was obtained in the same manner as in Example 1 except that the composition for forming a protective layer of 2.6 was used, and the exterior material 1 for a power storage device shown in FIG. 1 was obtained.

<Comparative Example 5>
In the composition for forming a protective layer, except that "13 parts by mass of an adduct body of trimethylolpropane and hexamethylene diisocyanate" was changed to "13 parts by mass of an adduct body of trimethylolpropane and tolylene diisocyanate (TDI)". In the same manner as in Example 1, the exterior material 1 for a power storage device shown in FIG. 1 was obtained.

In the table, the adduct body of trimethylolpropane and hexamethylene diisocyanate (HMDI) is referred to as "adduct body A", and the adduct body of pentaerythritol and hexamethylene diisocyanate (HMDI) is referred to as "adduct body B". Indicated, the adduct body of trimethylolpropane and tolylene diisocyanate (TDI) was described as "adduct body C".

The exterior materials for each power storage device obtained as described above were evaluated based on the following evaluation methods. The results are shown in Tables 1 to 3.

<Formability evaluation method>
Using an overhang molding machine manufactured by Amada Co., Ltd. (product number: TP-25C-X2), the exterior material for power storage devices is overhanged into a rectangular parallelepiped shape with a length of 55 mm, a width of 35 mm, and a depth of 8 mm, and the following criteria are used. The moldability was evaluated based on this.
(criterion)
"◎" ... There were no pinholes and no cracks occurred.
"○" ... There are no pinholes or cracks, but slight cloudiness is observed in the protective layer.
"△" ... Pinholes were slightly generated in a small part, but practically none.
"X" ... Pinholes and cracks occurred in the corners.

<Printability evaluation method>
A barcode (dot size: diameter 0.25 mm) was printed with white ink on the surface (outer surface) of the protective layer of each exterior material using an inkjet printer. Next, the printability was evaluated based on the following criteria from the viewpoint of whether or not the printed barcode can be read by the barcode reader without any problem and whether or not the printed barcode has bleeding.
(criterion)
"◎" ... Can be read with a barcode reader without any problem. There was no bleeding.
"○" ... Can be read with a barcode reader without any problem. There is a slight bleeding, but there is no problem.
"△" ... Blurring is observed to some extent, but it can be read with a barcode reader without any problem.
"×" ... I couldn't read it with a barcode reader. The degree of bleeding was large.

<Solvent resistance evaluation method (ethanol)>
Each exterior material is cut into a size of 10 cm in length × 10 cm in width to obtain a test piece, and after 1 mL (1 cc) of ethanol is dropped on the surface (outer surface) of the protective layer of the test piece, the diameter is 1 cm and the mass is 1 kg. A sliding member with cotton wrapped around the surface of the weight rubbed the droplet-attached portion of the test piece 10 times back and forth. The appearance of the surface (outer surface) of the protective layer of the test piece after being reciprocated 10 times was visually inspected, and the solvent resistance (ethanol) was evaluated based on the following criteria.
(criterion)
"◎" ... There was no change in appearance even after 10 round trips.
"○" ... There was no change in appearance from the 1st to 7th round trips, but the appearance changed after 8 round trips.
"Δ" ... There was no change in the appearance from the 1st to the 4th round trip, but the appearance changed after 5 round trips.
"X" ... The appearance changed after one round trip (poor solvent resistance).

<Solvent resistance evaluation method (methyl ethyl ketone)>
The solvent resistance (methyl ethyl ketone) was evaluated in the same manner as in the above solvent resistance evaluation method (ethanol) except that 1 mL of methyl ethyl ketone (MEK) was used instead of 1 mL of ethanol. The judgment criteria are the same as the above judgment criteria in the solvent resistance evaluation method (ethanol).

As is clear from the table, the exterior materials for power storage devices of Examples 1 to 15 of the present invention were excellent in moldability, good printability, and excellent solvent resistance.

On the other hand, in Comparative Examples 1 to 5 which deviate from the specified range of the present invention, there are the following problems. That is, the exterior material of Comparative Example 1 had poor printability. Further, in the exterior materials of Comparative Examples 2 to 5, the solvent resistance to MEK was remarkably poor.

The exterior material for a power storage device according to the present invention and the exterior case for a power storage device according to the present invention are, for example, as specific examples.
-Used as an exterior material and exterior case for various power storage devices such as lithium secondary batteries (lithium ion batteries, lithium polymer batteries, etc.), lithium ion capacitors, electric double-layer capacitors, and all-solid-state batteries. Further, examples of the power storage device according to the present invention include various power storage devices exemplified above.

1 ... Exterior material for power storage device 2 ... Base material layer 3 ... Sealant layer (inner layer)
4 ... Metal leaf layer 5 ... First adhesive layer (outer adhesive layer)
6 ... Second adhesive layer (inner adhesive layer)
7 ... Protective layer 8 ... Easy adhesive layer 9 ... Colored layer 10 ... Exterior case (molded body) for power storage device
15 ... Exterior member 30 ... Power storage device 31 ... Power storage device main body

Claims (1)

In the exterior material for a power storage device, which includes a base material layer made of a heat-resistant resin, a sealant layer as an inner layer, and a metal foil layer arranged between the base material layer and the sealant layer.
A protective layer is laminated on the surface of the base material layer opposite to the metal foil layer side.
The protective layer is formed of a polyfunctional isocyanate curing agent containing at least an aliphatic polyfunctional isocyanate compound and a polyester polyol having a hydroxyl group or a carboxyl group and having a number average molecular weight of 5,000 to 50,000 independently at least at both ends. An exterior material for a power storage device, which comprises 40% by mass or more of a polyester resin.

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