CN116995342A - Packaging material - Google Patents

Abstract

The present invention relates to a packaging material, a packaging container, an outer packaging material for an electrical storage device, an electrical storage device, and a method for manufacturing a colored adhesive composition. An object of the present invention is to provide a packaging material excellent in moldability, colorability, and strength. The present invention is directed to the packaging material 1, which includes a metal foil layer 52 laminated inside a heat-resistant resin base material layer 51, and a thermoplastic resin sealant layer 53 laminated inside the metal foil layer 52. A colored adhesive layer 61 is provided between the metal foil layer 52 and the base material layer 51 . The colored adhesive layer 61 is composed of a colored adhesive cured film containing a colored pigment and an adhesive. The colored adhesive cured film has a Young's modulus of 450 MPa to 700 MPa based on the tensile test based on JIS K7161-1:2014. .

Description

Packaging Materials

Technical field

The present invention relates to packaging materials as outer packaging materials for batteries (power storage equipment) such as notebook computers, mobile phones, vehicle-mounted (mobile type) or stationary type secondary batteries (lithium ion secondary batteries), and food products. Method for manufacturing packaging materials, packaging containers, electrical storage devices and colored adhesive compositions for pharmaceuticals.

Background technique

Increasingly, coloring is required to unify the appearance and color of electrical equipment and other equipment to be assembled. In particular, devices are often colored black in order to give them a sense of weight and luxury. In this case, batteries are increasingly also colored black.

As a packaging material for such equipment, a laminate in which a resin base material layer is laminated on the outer surface side of a metal foil layer and a resin sealant layer is laminated on the inner surface side is usually used. When the battery is colored black, etc. , there are the following methods: a method of coloring the resin layer used in packaging materials; a method of setting a printing layer under the base material layer; a method of coloring the adhesive layer between the base material layer and the metal layer; When the base material layer is composed of multiple layers, a method of coloring the adhesive layer between the layers; etc.

For example, Patent Document 1 discloses an example of adding a pigment as an identification mark to the adhesive layer between the base material layer and the metal foil layer of a battery packaging material, and describes that the pigment addition amount is 10% by mass to 30% by mass. It can be recognized within the range of mass % and the formability is also good.

In addition, Patent Document 2 discloses an example in which the base material layer is made into multiple layers (two layers) and a pigment is added as an identification mark to the adhesive layer between the two base material resin layers. It is described that the amount of the pigment added is It can be recognized in the range of 5 mass% to 30 mass%, and the formability is also good.

However, when adding pigments such as carbon black to the adhesive layer between the base material layer and the metal foil layer, if the amount of carbon black added to the adhesive layer is increased to make the adhesive layer black, the adhesive force will decrease, resulting in molding problems. Interlayer peeling occurs between the base material layer and the adhesive layer, and the molding may not be able to be molded into a prescribed shape.

In addition, such interlayer delamination (partial delamination) between the base material layer and the adhesive layer occurs not only during molding, but also during sealing of black packaging materials after enclosing electrodes and electrolytes, or when packaging with black packaging materials. It may also occur when the battery is used in a slightly harsh environment such as high temperature and humidity.

It should be noted that the problem of delamination is not limited to black packaging materials using carbon black, but may also occur in packaging materials colored with other pigments.

Under such circumstances, Patent Document 3 discloses that the addition amount of color pigments such as carbon black is limited to a predetermined range, thereby suppressing the decrease in adhesive force due to the addition of pigments to the adhesive layer and obtaining good results. technology such as formability.

existing technical documents

patent documents

Patent Document 1: Japanese Patent Application Publication No. 2011-054563

Patent Document 2: Japanese Patent Application Publication No. 2015-072911

Patent Document 3: Japanese Patent Application Publication No. 2021-109706

Contents of the invention

The problem to be solved by the invention

As described above, when adding a pigment such as carbon black to the adhesive layer to color the packaging material, it is one of the important factors to limit the amount of the pigment added to a predetermined range.

However, if only the amount of pigment added to the adhesive layer is set to a specific range, the dispersion state of the pigment in the adhesive layer may become uneven, and the pigment particles may aggregate unevenly and become an adhesive. Defects in the layer, the adhesion force decreases, and the Young's modulus of the adhesive layer decreases. Therefore, when molding into a container (shell) shape by deep drawing or embossing, there is a problem that the external force during the molding process cannot be efficiently dispersed and predetermined moldability cannot be obtained.

Preferred embodiments of the present invention are made in view of the above and/or other problems in the related art. Preferred embodiments of the present invention significantly improve existing methods and/or apparatus.

The present invention has been made in view of the above-mentioned problems, and an object thereof is to provide a packaging material excellent in moldability and colorability, and a packaging container using the packaging material, an outer packaging material for an electrical storage device, an electrical storage device, and a colored adhesive Methods for manufacturing pharmaceutical compositions.

Other objects and advantages of the present invention can be clarified by the following preferred embodiments.

Methods used to solve problems

In order to solve the above-mentioned problems, the present invention includes the following means.

[1] A packaging material including a metal foil layer laminated inside a heat-resistant resin base material layer and a thermoplastic resin sealant layer laminated inside the metal foil layer, wherein the metal foil layer and A colored adhesive layer is provided between the aforementioned base material layers, which is characterized in that:

The aforementioned colored adhesive layer is composed of a colored adhesive cured film containing a colored pigment and an adhesive,

The Young's modulus of the aforementioned colored adhesive cured film in the tensile test based on JIS K7161-1:2014 is 450 MPa to 700 MPa.

[2] The packaging material according to the preceding item 1, wherein the colored adhesive cured film has an elongation at break of 21% to 60% in a tensile test based on JIS K7161-1:2014.

[3] The packaging material according to the preceding item 1 or 2, wherein the colored adhesive layer contains 2 mass % or more and less than 5 mass % of the colored pigment,

The colored adhesive layer is a cured film of the colored adhesive of 5 g/m ² to 10 g/m ² .

[4] The packaging material according to any one of claims 1 to 3, wherein the adhesive of the colored adhesive layer contains a polyester resin as a main ingredient and a polyfunctional isocyanate as a curing agent. Two-liquid curing polyester urethane resin derived from chemical compounds,

The number average molecular weight (Mn) of the polyester resin as the main ingredient is 8,000 to 25,000, the weight average molecular weight (Mw) is 15,000 to 50,000, and their ratio (Mw/Mn) is 1.3 to 2.5.

The polyfunctional isocyanate compound as a curing agent contains 50 mol% or more of aromatic isocyanate.

[5] The packaging material according to the preceding item 4, wherein in the two-liquid curable polyester urethane resin, the polyester resin as the main ingredient uses dicarboxylic acid and glycol as raw materials,

The dicarboxylic acid includes an aliphatic dicarboxylic acid and an aromatic dicarboxylic acid in which the number of methylene groups in the methylene chain is an even number, and the content rate of the aromatic dicarboxylic acid is 40 mol% relative to their total amount. ~80 mol%.

[6] The packaging material according to any one of claims 1 to 5, wherein the metal foil layer has a chemical conversion coating on at least one surface thereof.

[7] The packaging material according to any one of claims 1 to 6, wherein a matte coating is provided on an outer surface of the base layer.

[8] A packaging container, wherein the packaging material according to any one of claims 1 to 7 has a molded portion formed by deep drawing molding or embossing molding.

[9] An outer packaging material for electrical storage equipment, characterized in that it is composed of the packaging material described in any one of the preceding paragraphs 1 to 7 and/or the packaging container described in the preceding paragraph 8.

[10] Electric storage equipment, characterized by:

The main body of the electrical storage equipment; and

The outer packaging material according to claim 9,

The main body of the electrical storage device is externally packaged using the external packaging material.

[11] A method for producing a colored adhesive composition constituting a colored adhesive cured film in the packaging material according to any one of the preceding items 1 to 7. Manufacturing method,

Mix the aforementioned color pigment into a vehicle (vehicle), and prepare a liquid colorant (Japanese: liquid colorant) in advance,

Mix the aforementioned liquid colorant into the main agent and the curing agent constituting the aforementioned adhesive to prepare a pigment-containing main agent for the adhesive, and then,

The pigmented adhesive main agent and the curing agent are blended to prepare the colored adhesive composition.

Effect of the invention

According to the packaging material of invention [1], since the colored adhesive layer contains a pigment, good colorability can be obtained. In addition, since the Young's modulus of the colored adhesive layer containing the colored pigment is limited to a predetermined range, the effect from external pressure can be efficiently dispersed, and sufficient strength and excellent moldability can be obtained. This enables, for example, sharp and deep molding, and prevents problems such as local cracking and peeling of the colored adhesive layer during molding and sealing, or when used in harsh environments with high temperature and humidity.

According to the packaging material of the invention [2], since the elongation at break is limited to a predetermined range, good formability can be obtained when deep drawing and embossing are performed. In addition, peeling of the base material layer does not occur, the adhesiveness of the base material layer can be further improved, and the occurrence of delamination can be suppressed.

According to the packaging material of invention [3], since the colored adhesive layer is a predetermined amount of a colored adhesive cured film, and the concentration (content rate) of the colored pigment in the colored adhesive layer is limited to a predetermined range, Therefore, uniform coloration properties can be obtained as a whole. In addition, it can prevent the colored adhesive layer from being fragile due to the inclusion of colored pigments, lengthen the fracture path (distance) of the colored adhesive cured film, increase the elongation at break, and fully maintain the base layer and the metal. The adhesion between foil layers enables further good formability when deep drawing and embossing are performed. Moreover, even if it is placed in a high-temperature and high-humidity environment after molding, the base material layer will not peel off and the appearance will be damaged. As a result, even in evaluation tests that are affected by the inclusion of colored pigments, especially those that are the most stringent In the warm water immersion test of the environmental test, the base material layer does not peel off, which can further improve the adhesion of the base material layer.

According to the packaging material of invention [4], since the colored adhesive layer contains a specific two-component curable polyester urethane (polyesterpolyurethane) resin, appropriate strength, elongation, and excellent heat resistance can be obtained. Furthermore, since the polyester resin as the main component of the colored adhesive layer is adjusted to a predetermined molecular weight distribution, the adhesive coating adaptability is also excellent. In addition, since the polyamide film as the base material layer is adjusted to a predetermined molecular weight distribution, the film as the base material layer is less likely to be damaged and good puncture resistance can be obtained.

According to the packaging material of the invention [5], the two-component curable polyester urethane resin contained in the colored adhesive layer has a specific composition as the main component of the polyester resin, so the adhesiveness is improved It is even more excellent and can more reliably prevent peeling between the base material layer and the metal foil layer.

Since the chemical conversion coating is provided on the surface of the metal foil layer in invention [6], corrosion of the metal foil layer can be prevented and the corrosion resistance of the entire packaging material can be improved.

According to the packaging material of invention [7], since a matte coating is provided on the surface of the base material layer, the formability and durability can be further improved, and the presence of the matte coating makes the packaging The appearance quality of the material is improved, defects such as close adhesion of packaging materials can be prevented, and packaging products can be easily handled.

The packaging container according to invention [8] is a product using the packaging material of the above invention, and therefore can obtain the same effect as above.

The outer packaging material for electrical storage equipment according to the invention [9] uses the packaging material and packaging container of the above-mentioned invention, and therefore can obtain the same effects as above.

The electrical storage device according to the invention [10] uses the outer packaging material of the above invention, and therefore can obtain the same effect as above.

According to the manufacturing method of invention [11], since a colored adhesive composition in which a colored pigment is uniformly dispersed can be produced, a colored adhesive cured film having the above-mentioned unique physical properties can be reliably formed.

Description of the drawings

[Fig. 1] Fig. 1 is a side cross-sectional view showing an electric storage device as an embodiment of the present invention.

[Fig. 2] Fig. 2 is an exploded perspective view showing the electrical storage device according to the embodiment.

[Fig. 3] Fig. 3 is a schematic cross-sectional view schematically showing the outer packaging material for electrical storage equipment according to the embodiment.

[Fig. 4] Fig. 4 is a schematic diagram for explaining MD and TD of the resin film.

[Fig. 5] Fig. 5 is an S-S curve diagram of a cured film of a two-component curable polyester urethane resin adhesive.

[Fig. 6] Fig. 6 is a perspective view of a molded article showing a packaging material sample used in an embodiment of the present invention.

Explanation of reference signs

1: Outer packaging materials (packaging materials)

10: Main body of power storage equipment

2: Disc-shaped components (packaging materials, outer packaging materials, packaging containers)

21: Recessed part (formed part)

3: Cover components (packaging materials, outer packaging materials)

51: Base material layer

52: Metal foil layer

53:Sealant layer

61: First adhesive layer (colored adhesive layer, colored adhesive composition, colored adhesive cured film)

63: Chemical conversion coating

Detailed ways

FIG. 1 is a side cross-sectional view showing an electrical storage device as an embodiment of the present invention, and FIG. 2 is an exploded perspective view showing the electrical storage device according to the embodiment.

As shown in the two figures, the electric storage device of this embodiment includes a case 11 and an electric storage device main body 10 such as an electrochemical element housed inside the case 11 .

The casing 11 is composed of a disk-shaped member (packaging container) 2 formed of the outer packaging material 1 and having a rectangular shape in plan view, and a cover member 3 formed of the outer packaging material (packaging material) 1 and having a rectangular shape in plan view.

The disk-shaped member 2 is composed of a molded product obtained by molding the outer packaging material 1 using a method such as deep drawing molding. The entire middle region of the disc-shaped member 2 except for the outer peripheral edge is recessed downward to form a recessed portion 21 that is rectangular in plan view, and an outer protrusion is integrally formed on the outer periphery of the opening edge of the recessed portion 21 shaped flange portion 22.

In addition, the cover member 3 is composed of the outer packaging material 1 formed into a sheet shape. The outer peripheral edge portion of the cover member 3 is configured as a flange portion 32 corresponding to the flange portion 22 of the disk-shaped member 2 .

The outer packaging material 1 as the disk-shaped member 2 and the cover member 3 is composed of an outer packaging laminated material which is a laminated sheet or film having softness and flexibility.

In addition, the power storage device main body 10 is not particularly limited, and examples thereof include a battery main body, a capacitor main body, a capacitor main body, and the like. The electrical storage device main body 10 is formed in a shape corresponding to the recessed portion 21 of the disk-shaped member 2 .

Then, with the electrical storage device main body 10 accommodated in the recessed portion 21 , the cover member 3 is placed on the disc-shaped member 2 so as to cover the recessed portion 21 , and the flanges of the disc-shaped member 2 and the cover member 3 are connected. The parts 22 and 32 are thermally welded to each other, thereby forming the power storage device of this embodiment.

Although illustration is omitted, one end (inner end) of the tab lead is connected to the power storage device main body 10 , and the other end (outer end) is disposed in a state of being led out to the outside of the power storage device. , electrical input and output to the electrical storage device main body 10 can be performed via the tab.

FIG. 3 is a schematic cross-sectional view schematically showing the basic structure of the outer packaging laminate material constituting the outer packaging material 1 in this embodiment. As shown in this figure, the outer packaging material (laminated material) 1 used in this embodiment includes: a base material layer (heat-resistant resin layer) 51; one side (inner surface) of the base material layer 51 is interposed with a The metal foil layer (barrier layer) 52 is bonded to the first adhesive layer 61 of the colored adhesive layer or the outer adhesive layer; and one side (inner surface) of the metal foil layer 52 is bonded to the inner side through The sealant layer (thermal adhesive resin layer) 53 is bonded to the second adhesive layer 62 of the adhesive layer. It should be noted that the chemical conversion coatings 63 and 63 are formed on both sides of the metal foil layer 52 , and the matte coating 50 is laminated on the outer surface of the base layer 51 .

In this embodiment, examples of the base material layer 51 include polyamide films, polyester films, and the like, and stretched films thereof can be used. Among them, biaxially stretched polyamide films, biaxially stretched polybutylene terephthalate (PBT) films, and biaxially stretched polyethylene terephthalate films are preferably used from the viewpoint of formability and strength. ester (PET) film or biaxially stretched polyethylene naphthalate (PEN) film.

Examples of polyamide films include nylon 6 films, nylon 6,6 films, nylon MXD films, and the like.

The base material layer 51 may be formed of a single layer or multiple layers. When formed of multiple layers, a multilayer structure formed of a PET film/polyamide film can be exemplified.

In order to improve the bonding strength with the adhesive 61, it is preferable to provide wettability and easy adhesion to the lower surface of the stretch film used as the base material layer 51, that is, the bonding surface with the first adhesive layer 61. deal with.

Here, in view of the requirements for higher capacity and improved safety of electrical storage devices (batteries), higher moldability and puncture resistance are desired for the base material layer 51 of the outer packaging material for electrical storage devices. However, according to The present inventor's research has revealed that in order to improve the latter's performance (puncture resistance), a polyamide film is more suitable than a polyester film, and it is further preferred to use a film that satisfies the following physical properties (1) to (5). Polyamide film provides good formability and puncture resistance.

(1) For the base material layer 51, it is preferable to adjust the hot water shrinkage ratio of TD and MD to 2.0% to 5.0%, and more preferably to 2.5% to 4.5%.

Here, as shown in FIG. 4 , "MD" refers to the molding direction of the resin film F (the flow direction of the resin), and "TD" refers to the direction orthogonal to MD. In addition, the hot water shrinkage rate refers to the dimensional change rate in the shrinkage direction (tensile direction) before and after immersion when the film (object to be measured) is immersed in hot water at 100° C. for 5 minutes. For example, when the size in the shrinkage direction (MD or TD) before hot water immersion is set to "X" and the size in the shrinkage direction (MD or TD) after hot water immersion is set to "Y", the shrinkage direction (MD or TD) is The hot water shrinkage (%) of TD) is calculated from the relational expression {(X-Y)/X}×100. In addition, in this invention, as "hot water shrinkage rate" which shows the characteristic value of a polyamide film, it is preferable to adopt the average value of hot water shrinkage rate (average hot water shrinkage rate). In the present invention, the average hot water shrinkage rate refers to the hot water shrinkage rate at two points at both ends and the hot water shrinkage rate at one point at the center with respect to one direction of the sheet (film) to be measured. The average value of the hot water shrinkage at the point. Of course, in the present invention, depending on the size of the electrical storage device main body 10, as the "hot water shrinkage rate" indicating the characteristic value of the polyamide film, the hot water shrinkage rate measured at a specific position (the heat shrinkage rate at the reference position) may also be used. water absorption) rather than the average.

(2) The difference between the MD hot water shrinkage rate and the hot water shrinkage rate TD of the base material layer 51 is preferably adjusted to 1.5% or less, more preferably 1.2% or less. Specifically, when the average hot water shrinkage rate of MD is "MDz" and the hot water shrinkage rate of TD is "TDz", it is preferable that the relational expression ∣MDz-TDz|≤1.5% be established, and more preferably , it is appropriate to adjust it to ∣MDz-TDz∣≤1.2% or less.

(3) It is preferable to adjust the MD elastic modulus and the TD elastic modulus of the base material layer 51 to 1.5 GPa to 3 GPa, more preferably to 2.0 GPa to 2.5 GPa.

(4) It is preferable to adjust at least one of the TD breaking strength and the MD breaking strength of the base material layer 51 to 320 MPa or more, and more preferably to 400 MPa or less.

(5) The number average molecular weight of nylon as the polyamide film constituting the base material layer 51 is preferably adjusted to 15,000 to 30,000, more preferably 20,000 to 25,000.

Here, in this embodiment, when the hot water shrinkage ratio of TD and MD is 2.0% or more, it has moderate flexibility and can ensure good moldability as the base material layer 51 . In addition, since the content is 5.0% or less, excessive flexibility can be avoided as the base material layer 51 and desired strength can be maintained.

In addition, in this embodiment, when the difference in the hot water shrinkage rates of TD and MD is adjusted within the above-mentioned specific range, the force from the external pressure can be efficiently dispersed, and the base material layer 51 can reliably maintain the desired performance. Strength of.

In addition, when the elastic modulus of TD and MD is adjusted within the above-mentioned specific range, the base material layer 51 can more reliably maintain appropriate flexibility and strength.

In addition, when the breaking strength of TD and MD is adjusted within the above-mentioned specific range, the desired strength can be more reliably obtained as the base material layer 51 .

By using the polyamide film having the above-mentioned characteristics as the base material layer 51 as described above, the outer packaging material 1 with good moldability and sufficient puncture resistance can be obtained.

In addition, when the number average molecular weight of the nylon as the base material layer 51 is 15,000 or more, the base material layer 51 becomes less likely to be broken. In addition, when the molecular weight is 30,000 or less, the flexibility of the base material layer 51 can be maintained and the base material layer 51 becomes less likely to be broken.

In addition, in this embodiment, it is preferable to adjust the relative viscosity of the polyamide film as the base layer 51 to 2.9 to 3.1. That is, when the relative viscosity is adjusted to the above-mentioned specific range, the base material layer 51 can be provided with strength and flexibility more effectively, and the outer packaging material 1 can reliably obtain an outer shell with good moldability and high puncture resistance. Packaging Materials.

Here, in this embodiment, the puncture strength of the outer packaging material 1 is preferably in the range of 22N to 30N, more preferably 24N to 30N, and even more preferably 26N to 30N.

In addition, in this embodiment, the thickness of the base material layer 51 is preferably adjusted to 9 μm to 50 μm, and more preferably, the thickness is adjusted to 12 μm to 30 μm. Among them, when using a polyester film as the base material layer 51, the thickness is preferably adjusted to 9 μm to 50 μm, and when using a polyamide film, the thickness is preferably adjusted to 10 μm to 50 μm. By setting the thickness to be equal to or greater than the preferred lower limit, sufficient strength as a packaging material can be ensured, and by setting it to be equal to or less than the preferred upper limit, the stress during embossing molding and drawing molding can be reduced, and the thickness can be reduced. Improve formability.

Here, the distribution of hot water shrinkage in the polyamide film of this embodiment will be described. First, in a square polyamide film, the hot water shrinkage rates at three locations of the longitudinal direction (MD) and the center line are used as fixed-point hot water shrinkage rates at three points in the MD, and the two sides and the center line in the transverse direction (TD) are When the hot water shrinkage rates at these three points are used as the fixed-point hot water shrinkage rates of the three points of TD, it is preferable to use the fixed-point hot water absorption rates of the three points of the MD and the fixed-point hot water absorption rates of the three points of the TD. A total of six fixed-point heat shrinkage points are used. Among the water shrinkage rates, the difference between the maximum fixed-point hot water shrinkage rate and the minimum fixed-point hot water shrinkage rate has been adjusted to 2.5 or less.

It should be noted that the average value of the hot water shrinkage rates at three fixed points in MD is equivalent to the average hot water shrinkage rate in MD, and the average hot water shrinkage rate at three points in TD is equivalent to the average hot water shrinkage rate in TD. Rate.

Here, the three regions indicated by dotted lines in FIG. 4 are square regions with the same size in the polyamide film (base material layer 51 ), and the square regions satisfy the above-mentioned hot water shrinkage distribution conditions. , suppresses uneven flexibility in the entire area of the base material layer 51, so even if external stress is applied, it is dispersed throughout the base material layer 51, making it less likely to be damaged, and the strength can be reliably improved.

In this embodiment, the base material layer 51 is formed of a polyamide film. As mentioned above, other layers may be laminated on the base material layer 51 .

In addition, the base material layer 51 is preferably a resin whose melting point is 10° C. or more higher than all the resins constituting the sealant layer 53 , and more preferably, a resin whose melting point is 20° C. or more higher. That is, when this structure is adopted, when the sealant layer 53 is thermally welded, adverse effects on the base material layer 51 due to heat can be avoided.

The sealant layer (thermal weldable resin layer, thermoplastic resin layer) 53 has excellent chemical resistance even against highly corrosive electrolytes used in lithium ion secondary batteries and the like, and is responsible for packaging materials. 1. Provides heat sealability.

The sealant layer 53 is not particularly limited, but is preferably a layer based on a thermally fusible resin unstretched film. The thermally fusible resin unstretched film is preferably composed of an unstretched film selected from the group consisting of polyethylene, polypropylene, and olefin-based films from the viewpoint of chemical resistance and heat sealability. It is formed of at least one heat-bonding resin from the group consisting of copolymers, acid-modified products thereof, and ionomers.

The thickness of the sealant layer 53 is preferably set to 20 μm to 80 μm, and more preferably, the thickness is set to 25 μm to 50 μm. That is, by setting the thickness to 20 μm or more, the occurrence of pinholes can be sufficiently prevented, and by setting the thickness to 80 μm or less, the amount of resin used can be reduced, thereby achieving cost reduction.

It should be noted that the sealant layer 53 may be a single layer or multiple layers. In the case of a multi-layered film, a three-layered film in which random polypropylene films are laminated on both sides of a block polypropylene film can be exemplified.

In this embodiment, the metal foil layer 52 serves as a gas barrier to prevent the intrusion of oxygen and moisture.

The metal foil layer 52 is not particularly limited, and examples thereof include aluminum foil, copper foil, stainless steel foil, and the like. Generally, aluminum foil can be used. Among them, aluminum foil can be preferably used. In particular, when an Al-Fe-based alloy foil containing 0.7% by mass to 1.7% by mass of Fe is used, it has excellent strength and ductility and can obtain good formability.

The thickness of the metal foil layer 52 is preferably set to 20 μm to 100 μm, more preferably, 25 μm to 60 μm. That is, by setting the thickness to 20 μm or more, pinholes can be prevented from being generated during rolling during the production of metal foil, and by setting the thickness to 100 μm or less, stress during embossing molding and drawing molding can be reduced, thereby improving formability.

Although the resin base material layer 51 and the sealant layer 53 are laminated on the outer surface side and the inner surface side of the metal foil layer 52, although the amount is extremely small, light, oxygen, and liquid may come from the outside (the base material layer 51 side) After entering the resin layers 51 and 53 , the contents (battery electrolyte, food, pharmaceuticals, etc.) may penetrate into the resin layers 51 and 53 from the inside (the sealant layer 53 side). If these invaders reach the metal foil layer 52 , they will cause corrosion of the metal foil layer 52 . Therefore, in the present invention, the corrosion resistance of the metal foil layer 52 can be improved by forming the chemical conversion film 63 with high corrosion resistance on the surface of the metal foil layer 52 .

For example, in the case of chromate treatment, an aqueous solution of the mixture of any one of the following 1) to 3) is applied to the surface of the degreased metal foil and then dried.

1) A mixture of at least one of phosphoric acid, chromic acid, a metal salt of fluoride, and a non-metal salt of fluoride

2) Phosphoric acid, a mixture with any one of acrylic resin, chitosan derivative resin and phenol resin, and at least one of chromic acid and chromium (III) salt

3) Phosphoric acid, any of acrylic resins, chitosan derivative resins, phenol resins, at least one of chromic acid and chromium (III) salts, and metal salts and fluorides of fluoride A mixture of at least one of the non-metallic salts

The chromium adhesion amount of the chemical conversion coating 63 is preferably set to 0.1 mg/m ² to 50 mg/m ² , more preferably, 2 mg/m ² to 20 mg/m ² .

It should be noted that this includes any case where the chemical conversion coating 63 is applied to both surfaces of the metal foil layer 52 or a case where it is applied to one of the surfaces.

In this embodiment, the first adhesive layer (colored adhesive layer) 61 is responsible for bonding the metal foil layer 52 and the base material layer 61 and provides color (including achromatic color) to the outer surface side of the outer packaging material 1 The layer is composed of a cured film (colored adhesive cured film) of a colored adhesive composition containing a colored pigment and a specific adhesive (adhesive component).

The coloring pigment is not particularly limited, and azo pigments, phthalocyanine pigments, condensed polycyclic pigments, inorganic pigments, etc. can be suitably used. Examples of the black pigment include carbon black, and examples of the white pigment include TiO ₂ and SiO ₂ .

As the color pigment, it is preferable to use a color pigment with an average particle diameter of 0.05 μm to 5 μm, and particularly preferably, a color pigment with an average particle diameter of 0.1 μm to 2.5 μm.

When dispersing the pigment, it is preferable to use a pigment dispersing machine. When dispersing the pigment, a pigment dispersant such as a surfactant may also be used.

However, when a pigment with a small average particle diameter is added to an adhesive, if the pigment is added directly, secondary aggregated particles of the pigment may be generated, and the pigment cannot be uniformly dispersed in the adhesive.

Therefore, for example, a liquid toner composed of an ink (also referred to as "high-concentration ink") obtained by dissolving a pigment at a high concentration in components other than the pigment such as a color developing material to be described later is prepared in advance, and the liquid is By adding the coloring agent to the main agent for the adhesive and mixing it, secondary agglomeration of particles and precipitation of the pigment are less likely to occur, and a colored adhesive in which the pigment is uniformly dispersed in the adhesive at a predetermined content can be produced. Adhesive composition.

Ink as a liquid colorant is a product produced by mixing a colorant such as a pigment with a vehicle (a mixture of a resin and a solvent) as a color developing material to prepare an ink base, and adding an auxiliary agent (surface Activators, viscosity regulators, antistatic agents, antioxidants, pigment dispersants, leveling agents, anti-settling agents, defoaming agents, etc.), through the grinding and dispersing process using various grinders, the colorants are evenly dispersed .

As the resin for the vehicle, one or two of a copolymer of vinyl chloride and vinyl acetate, chlorinated rubber, chlorinated polypropylene, acrylic resin, polyamide resin, polyurethane resin, and nitrocellulose can be used in combination. More than one species. In the present invention, as the resin for the vehicle, it is preferable to use the same polyester resin as the main component for the adhesive. This can improve the compatibility (miscibility) with the main component of the adhesive.

As the solvent for the vehicle, one or more of toluene, methyl ethyl ketone, ethyl acetate, isopropyl alcohol, etc. can be used in combination. In the present invention, as the solvent for the vehicle, ethyl acetate, which can also be used as the solvent for the adhesive, is preferably used. If necessary, toluene and methyl ethyl ketone can also be used as the co-solvent.

As the pigment, as mentioned above, azo pigments, phthalocyanine pigments, condensed polycyclic pigments, inorganic pigments, etc. can be used. In particular, carbon black is recommended as the black pigment.

The mixing ratio of each component constituting the ink is preferably: resin for vehicle: 15% to 25% by mass, solvent for vehicle: 40% to 70% by mass, and colorant (pigment): 5% to 5% by mass. 50 mass%, additives: 1 mass% to 5 mass%.

In the present invention, carbon black (CB) is used as a colorant, and a black ink with a pigment concentration of 30 mass% to 40 mass% is prepared in advance (resin: solvent: CB: auxiliary = 15 mass% to 25 mass%: 40 mass% ~45 mass%: 30 mass% to 40 mass%: 3 mass% to 5 mass%) as a liquid toner.

In the manufacturing method of ink, the process (preparation process) of mixing a vehicle (polyester resin, solvent), a pigment (carbon black), and other additives is important. In the preparation process, in order to easily knead the resin component, it is preferable to use a solvent that becomes a component of the ink.

In particular, when producing an ink containing a pigment, during or after the preparation process, it is preferable to include kneading a mixture containing a resin, a solvent, a pigment, etc., and finely dispersing the particles of the pigment into desired particles. diameter process (dispersion process).

In this dispersion step, for example, a paint shaker, a ball mill, an attritor, a sand mill, a bead mill, a DYNO ball mill (DYNO-MILL), a roller mill ( Various dispersing machines such as roll mill, ultrasonic mill, and high-pressure impact disperser. In the dispersion process, one type of disperser may be used to perform the dispersion process once or several times, or two or more types of dispersers may be used in combination to perform the dispersion process several times.

When producing an ink containing a pigment, the above-mentioned dispersion step is important. By adding an ink in which a pigment is dispersed uniformly at a high concentration so that the pigment content becomes a predetermined amount, the adhesive base agent is suppressed. The pigments form secondary agglomerated particles with each other, allowing the pigments to be evenly dispersed in the main agent of the adhesive. After the pigment is added to the adhesive, the pigment will not settle even if it is left for several months, and has good pigment dispersion. Main agent for adhesive.

By reacting the main agent for the adhesive (polyester resin) with the pigment added and the isocyanate curing agent, a uniform colored adhesive composition without coating film defects caused by secondary agglomeration of pigment particles can be obtained , a colored adhesive cured film with a predetermined good Young's modulus, and good shielding, adhesiveness, water resistance and chemical resistance can be obtained.

The adhesive component of the first adhesive layer 61 is composed of an adhesive containing a two-pack curable polyester urethane resin based on a polyester resin as a main ingredient and a polyfunctional isocyanate compound as a curing agent. In the present invention, the molecular weight of the polyester resin as the main component of the two-liquid curable polyester urethane resin is specified, and the type of the polyfunctional isocyanate compound as the curing agent is specified, thereby improving the viscosity. It has excellent bonding strength and formability, and can suppress delamination during deep molding during the molding of the outer packaging material 1.

The above-mentioned polyester resin as the main ingredient is a copolymer using dicarboxylic acid and diol as raw materials. Preferred materials and compositions are as follows.

As the dicarboxylic acid, both aliphatic dicarboxylic acid and aromatic dicarboxylic acid are preferably used. In addition, the odd or even number of methylene groups in the methylene chain of an aliphatic dicarboxylic acid is a factor that affects the crystallinity of the resin. A dicarboxylic acid with an even number of methylene groups produces a hard resin with high crystallinity. Aliphatic dicarboxylic acids having an even number of methylene groups are preferably used. Examples of the aliphatic dicarboxylic acid having an even number of methylene groups include succinic acid (methylene number 2), adipic acid (methylene number 4), suberic acid (methylene number 6), and decane. Diacid (methylene number 8).

Examples of aromatic dicarboxylic acids include isophthalic acid, terephthalic acid, naphthalenedicarboxylic acid, and phthalic anhydride.

In addition, by setting the content rate of aromatic dicarboxylic acid in the range of 40 mol% to 80 mol% with respect to the total amount of aliphatic dicarboxylic acid and aromatic dicarboxylic acid, in other words, by adding the aliphatic dicarboxylic acid to The acid content is limited to the range of 20 mol% to 60 mol%, thereby producing a resin with high adhesive strength and good moldability, forming a shell with high side walls that can be molded into a molded product, and suppressing the metal foil layer 52 The outer packaging material (packaging material) 1 is peeled off from the base material layer 51 .

Here, when the aromatic dicarboxylic acid content is less than 40 mol%, the physical properties of the film decrease and aggregation and peeling become likely to occur. Therefore, interlaminar peeling may occur.

On the other hand, when the aromatic dicarboxylic acid content exceeds 80 mol%, the resin becomes hard and the adhesive performance tends to decrease. A particularly preferred aromatic dicarboxylic acid content is 50 mol% to 70 mol%.

Examples of the glycol in the polyester resin that is the main component of the adhesive component include ethylene glycol, propylene glycol, 1,3-butanediol, 1,4-butanediol, diethylene glycol, and dipropylene glycol. , neopentyl glycol, 1,5-pentanediol, 1,6-hexanediol, octanediol, 1,4-cyclohexanediol, 2-butyl-2-ethyl-1,3-propanediol .

Among the molecular weights of the polyester resin, it is preferable to set the number average molecular weight (Mn) to a range of 8,000 to 25,000 and the weight average molecular weight (Mw) to a range of 15,000 to 50,000, and their ratio (Mw/Mn ) is 1.3~2.5. When the number average molecular weight (Mn) is 8,000 or more and the weight average molecular weight (Mw) is 15,000 or more, suitable coating film strength and heat resistance can be obtained. By setting the number average molecular weight (Mn) to 25,000 or less and the weight average molecular weight (Mw) ) is 50,000 or less, so that it does not become too hard and can obtain appropriate elasticity of the coating film.

In addition, by setting their ratio (Mw/Mn) to 1.3 to 2.5, a suitable molecular weight distribution can be achieved, and a balance between adhesive coating adaptability (wide distribution) and performance (narrow distribution) can be maintained.

Among the above polyester resins, a particularly preferred number average molecular weight (Mn) is 10,000 to 23,000, a particularly preferred weight average molecular weight (Mw) is 20,000 to 40,000, and a particularly preferred (Mw/Mn) is 1.5 to 2.3.

In addition, the molecular weight of the polyester resin can be adjusted by chain extension with a polyfunctional isocyanate. That is, when the polyester component in the main ingredient is connected with NCO, a polymer with a hydroxyl group at the end is generated, and the molecular weight of the polyester resin can be adjusted by adjusting the equivalent ratio of the isocyanate group to the hydroxyl group of the polyester. In the present invention, it is preferable to use a substance connected so that their equivalent ratio (OH/NCO) becomes 1.01 to 10. Another method of adjusting the molecular weight includes changing the reaction conditions of the polycondensation reaction of dicarboxylic acid and diol (adjustment of the molar ratio of dicarboxylic acid and diol).

In addition, in this embodiment, epoxy resin and acrylic resin can be added as an additive to the main agent in the adhesive component.

Regarding the polyfunctional isocyanate compound of the above-mentioned curing agent that is an adhesive component, various aromatic, aliphatic, and alicyclic isocyanate compounds can be used. Specific examples include aliphatic hexamethylene diisocyanate (HDI), isophorone diisocyanate (IPDI), aromatic toluene diisocyanate (TDI), and diphenylmethane diisocyanate. One or more polyfunctional isocyanate modified products of diisocyanates such as (MDI).

As modification methods, in addition to adducts with polyfunctional active hydrogen compounds such as water, glycerol, and trimethylolpropane, examples include isocyanuration, carbodiimidation, and polymerization. One type or two or more types selected from these may be mixed and used, such as a polyfunctional isocyanate modified product of a multimerization reaction. However, in order to increase the adhesive strength after curing and obtain the effect of preventing peeling of the base layer 51, it is preferable to contain 50 mol% or more of the aromatic isocyanate compound. A more preferred content of the aromatic isocyanate compound is 70 mol% or more.

In the two-component curable polyester urethane resin as an adhesive component, the mixing ratio of the main agent and the curing agent is preferably such that the isocyanate functional group (-NCO) is used per mole of the polyol hydroxyl group (-OH). ) is blended in a ratio of 2 mol to 25 mol. When their molar ratio (-NCO)/(-OH) is less than 2, the number of isocyanate functional groups (-NCO) decreases, and a sufficient curing reaction does not proceed, resulting in insufficient coating film strength and heat resistance. sex. On the other hand, when (-NCO)/(-OH) exceeds 25 and the number of isocyanate functional groups (-NCO) increases, there is a possibility that the reaction with functional groups other than the polyol proceeds excessively, causing the coating film to become excessively hard and unable to Get the appropriate elongation. A particularly preferred molar ratio of polyol hydroxyl groups to isocyanate functional groups (-NCO)/(-OH) is 5 to 20.

For a colored adhesive composition composed of an adhesive (two-liquid curable polyester urethane resin) and a liquid colorant (resin, solvent, CB, auxiliary agent), it is preferable that the cured film after the reaction ( The colored adhesive cured layer) has the following physical properties.

For the above-mentioned cured film, in order to ensure good formability of the sealing packaging material and bonding strength between layers, the Young's modulus based on the tensile test (JIS K7161-1) is preferably 450 MPa to 700 MPa, and particularly preferably 450 MPa. ~650MPa.

In addition, the breaking strength in the tensile test based on JIS K7161-1 is preferably 20 MPa to 60 MPa, and particularly preferably the breaking strength is 30 MPa to 50 MPa. In addition, the elongation at break in the tensile test based on JIS K7161-1 is preferably 20% to 100%, particularly preferably 20% to 60%, and still more preferably 21% or more.

Furthermore, the tensile stress-strain curve (S-S curve) preferably does not show a decrease in strength before fracture. Figure 5 shows three patterns of S-S curves. Relative to the tensile stress, the strain of pattern A is small, and the strain of pattern B is large. However, the strain increases with the increase of tensile stress, and no decrease in strength before fracture is observed. On the other hand, regarding Pattern C, the tensile stress decreases as the amount of strain increases, showing a decrease in strength before fracture. In the present invention, it is preferable that the cured film of the two-component curable adhesive has no strength decrease in the S-S curve. It is further preferred that there is no inflection point where the intensity changes sharply in the S-S curve.

In addition, the colored adhesive cured film in the packaging material of the present invention contains a predetermined amount of a colored pigment, and the colored pigment functions as a reinforcing material, and its Young's modulus is higher than that of a cured adhesive film that does not contain the colored pigment. The Young's modulus of the film is higher, and by utilizing this high Young's modulus, the packaging material of the present invention can obtain good formability.

For the above-mentioned adhesive containing a two-liquid curable polyester urethane resin, the dicarboxylic acid and glycol that are the raw materials of the polyester resin are polycondensed, and if necessary, further chain extended with a polyfunctional isocyanate. Mix the solvent and various additives such as urethanization reaction catalyst, coupling agent to improve adhesion, epoxy resin, defoaming agent, leveling agent, ultraviolet absorber, and antioxidant to form a flowable form. A polyester resin solution is prepared by blending a polyfunctional isocyanate compound as a curing agent or further blending a solvent into a low-viscosity fluid.

Preferred conditions (1) and (2) for the components in the colored adhesive composition constituting the first adhesive layer 61 are as follows. In addition, the content rate described below is the ratio of solid content which does not contain a solvent.

(1) The preferred content rate of the color pigment is 2 mass % or more and less than 5 mass % with respect to the total amount of the color pigment and the polyester resin (the main ingredient of the two-liquid curable polyester urethane resin) . In addition, by making the content of the color pigment less than 5% by weight, base material layers such as ONY (biaxially stretched nylon) films can be sufficiently suppressed even in severe environments such as high-temperature and humid environments and warm water immersion environments. of layering.

(2) The coating amount of the colored adhesive composition as the first adhesive layer 61 is 5 g/m ² to 10 g/m ² .

Based on the above (1) and (2), the content of the colored pigment contained in the first adhesive layer 61 is in the range of 0.1 g/m ² or more and less than 0.5 g/m ² . However, this colored pigment has When the content is less than 0.25 g/m ² , the shielding effect and visual effect are insufficient, which may cause problems in terms of design, which is not ideal. In addition, when the content of the color pigment exceeds 0.45 g/m ² , the visual effect is not improved, but may become prone to peeling in the warm water immersion test described below. Therefore, the effective content range of the color pigment contained in the first adhesive layer 61 of the present invention is in the range of 0.25g/m ² to 0.45 g/m ² , and the more preferable content range of the color pigment is 0.25 g/m ² ~0.35g/ ^m2 range.

After the battery packaging material is formed, when a 45°C warm water immersion test is performed as the most stringent environmental test, when the content of the coloring pigment exceeds 0.45g/ ^m2 , the first adhesive layer 61 becomes hard and brittle, and becomes brittle and hard. The adhesive force of the metal foil layer 52 decreases, which causes the base material layer (heat-resistant resin layer) 51 to peel off in the warm water immersion test.

However, in the general environmental test after the ^battery packaging material is molded (high temperature and high humidity storage test at 70°C The (heat-resistant resin layer) 51 hardly peels off and can be used.

In addition, when the content of the color pigment is 0.5 g/m ² or more, the possibility of peeling of the base material layer 51 in the high-temperature and high-humidity storage test increases.

When the coating amount of the first adhesive layer (colored adhesive composition) 61 is less than 5 g/m ² , the content of the colored pigment becomes small, and as mentioned above, the effect of concealing the metal foil layer becomes smaller, and further, it is possible to see The metallic luster is lost and the heaviness is impaired.

In addition, when the coating amount of the first adhesive layer 61 exceeds 10 g/m ² , the processability is significantly deteriorated, resulting in an increase in cost. The preferred coating amount of the colored adhesive composition is 6 g/m ² to 10 g/m ² .

In addition, the method of laminating the metal foil layer 52 and the base material layer 51 is not limited, but a method called dry lamination is recommended. Specifically, the prepared colored adhesive composition is applied to the upper surface (outer surface) of the metal foil layer 52 or the lower surface (inner surface) of the base material layer 51 or both surfaces, and the solvent is evaporated. After forming the dry film, the metal foil layer 52 and the base material layer 51 are bonded together. Then, it is further cured according to the curing conditions of the two-liquid curable polyester urethane resin. Thereby, the metal foil layer 52 and the base material layer 51 are joined via the 1st adhesive layer 61. In addition, as a coating method of a colored adhesive composition, a gravure coating method, a reverse roll coating method, a lip roller coating method, etc. are mentioned.

The second adhesive layer (non-colored adhesive layer) 62 is not particularly limited, and examples thereof include polyurethane adhesives, acrylic adhesives, epoxy adhesives, and polyolefin adhesives. , elastic system adhesives, fluorine-based adhesives, acid-modified polypropylene adhesives, etc.

Among them, acrylic adhesives and polyolefin adhesives are preferably used. In this case, the electrolyte resistance and water vapor barrier properties of the outer packaging material 1 can be improved.

The method of laminating the metal foil layer 52 and the sealant layer 53 is not limited. Similar to the above-mentioned lamination of the metal foil layer 52 and the base material layer 51, an example of the method is to apply the adhesive constituting the second adhesive layer 62. The dry lamination method is to apply the agent and dry it before laminating.

The matte coating layer 50 is laminated on the outer surface of the base material layer 51 to provide good sliding properties to the surface of the outer packaging material 1 and to improve formability.

The matte coating layer 50 is formed from a resin composition in which inorganic fine particles are dispersed in a heat-resistant resin component. Among them, the matte coating layer 50 preferably has a structure including a resin composition containing 0.1% by mass to 1% by mass of inorganic fine particles with an average particle diameter of 1 μm to 10 μm in a two-liquid curable heat-resistant resin. Examples of the heat-resistant resin include acrylic resins, epoxy resins, polyester resins, urethane resins, polyolefin-based resins, fluorine-based resins, and the like. Particularly from the viewpoint of heat resistance, From the viewpoint of excellent chemical resistance, it is preferable to use fluorine-based resins based on tetrafluoroethylene or fluoroethylene vinyl ether. The inorganic fine particles are not particularly limited, and examples thereof include silica, alumina, calcium oxide, calcium carbonate, calcium sulfate, calcium silicate, and the like. Among them, silica is preferably used.

The matte coating layer 50 is formed by applying a matte coating composition containing the above-mentioned inorganic fine particles and a heat-resistant resin to the surface of the base material layer 51 and curing the composition.

The thickness of the matte coating layer 50 after curing is preferably in the range of 0.5 μm to 5 μm. If it is thinner than the above lower limit, the effect of improving sliding properties cannot be expected. If it is thicker than the upper limit, costs may increase, which is undesirable. A particularly preferred thickness is in the range of 1 μm to 3 μm.

The gloss value of the surface of the matte coating layer 50 is preferably set to 1% to 15% based on the 60° reflection angle measurement value based on JIS Z8741. The gloss value is measured at a reflection angle of 60° using, for example, a gloss meter "micro-TRI-gloss-s" manufactured by BYK Corporation.

The timing of the step of forming the matte coating layer 50 is not limited, but it is preferably performed after the step of bonding the base material layer 51 to the metal foil layer 52 via the first adhesive layer 61 . At present, it is implemented after laminating a non-stretched polypropylene (CPP) film on the base material layer 51 .

It should be noted that in the above embodiment, the case where the sealing packaging material of the present invention is used as an outer packaging material for electrical storage equipment such as batteries has been described as an example. However, the present invention is not limited to this. The packaging material can also be used as a packaging material for sealing and sealing food, medicine, and other contained items.

In addition, in the above embodiment, the case where the sheet-like outer packaging material (packaging material) 1 is used as the cover member 3 has been described, but the present invention is not limited to this. In the present invention, the cover member 3 may be molded. For example, a cover member may be formed from a molded product having a hat-shaped cross section in which the central portion is recessed (bulged) upward, and the cap-shaped cover member may cover the above-mentioned disk-shaped member from above. The parts are jointed and integrated. In addition, in the present invention, two unformed sheet-like outer packaging materials (packaging materials) 1 may be stacked so as to sandwich the main body of the electrical storage device, and the outer peripheral edges thereof may be thermally welded. Form a shell.

In addition, in the above-mentioned embodiment, in order to form the casing, the case where two pieces of outer packaging materials (outer packaging laminate materials) are used as an example has been described. However, the present invention is not limited to this. In the present invention, the outer packaging materials that form the casing are There is no limit on the number of packaging materials, it can be 1 or 3 or more.

In addition, of course, the packaging material of the present invention does not necessarily need to be provided with the matte coating layer 50, the chemical conversion coating layer 63, etc., which are preferred elements.

Example

Next, examples including the gist of the present invention and comparative examples for deriving the effects thereof will be described. It goes without saying that the present invention is not limited by the following examples.

In the following Examples 1 to 8 and Comparative Examples 1 to 5, an outer packaging material (packaging material) with a laminated structure shown in FIG. 3 was produced. As shown in Table 1, in Examples and Comparative Examples, only the structure of the first adhesive layer (coloring adhesive layer) is different, and the other structures are common.

[Table 1]

<Example 1>

As the metal foil layer, an aluminum foil made of JIS H4160 A8079 with a thickness of 35 μm was prepared. Furthermore, a chemical conversion treatment liquid containing polyacrylic acid, a trivalent chromium compound, water, and alcohol was applied to both sides of the aluminum foil and dried at 150° C. to form a chemical conversion coating. The chromium adhesion amount based on this chemical conversion coating is 10 mg/m ² .

As a base material layer, a biaxially stretched nylon film with a thickness of 15 μm was prepared. The bonding surface (lower surface) with the first adhesive layer in this film was subjected to corona treatment.

For the biaxially stretched nylon film as the base material layer, the TD hot water shrinkage rate is 3.8%, the MD hot water shrinkage rate is 2.3%, and the difference in hot water shrinkage rate between TD and MD (TD-MD) It is 1.5%, the TD elastic modulus is 1.5GPa, the MD elastic modulus is 2.0GPa, the TD breaking strength is 322MPa, the MD breaking strength is 281MPa, and the number average molecular weight of polyamide is 18,000.

The colored adhesive composition constituting the first adhesive layer is prepared by the following method using a two-liquid curable polyester urethane resin as an adhesive component and carbon black as a colored pigment.

First, a polyester resin (polyester polyol) as the main component of a two-liquid curable polyester urethane resin is produced. For this main ingredient, 30 mole parts of neopentyl glycol, 30 mole parts of ethylene glycol, and 40 mole parts of 1,6-hexanediol were melted at 80°C and stirred at 210°C to form an aliphatic dihydrogen. A polycondensation reaction was carried out for 20 hours using 30 mole parts of adipic acid (methylene number 4) as a carboxylic acid and 70 mole parts of isophthalic acid as an aromatic dicarboxylic acid, to obtain a polyester polyol. The polyester polyol had a number average molecular weight (Mn) of 12,000, a weight average molecular weight (Mw) of 20,500, and their ratio (Mw/Mn) was 1.7. Furthermore, 60 parts by mass of ethyl acetate was added to 40 parts by mass of this polyester polyol to prepare a fluid polyester polyol resin solution. In addition, the hydroxyl value is 2.2 mgKOH/g (solution value).

On the other hand, 20 parts by mass of the same polyester polyol as described above as the vehicle resin, 40 parts by mass of ethyl acetate as the vehicle solvent, and carbon black with an average particle diameter of 1.0 μm as the colorant were used. A total of 35 parts by mass and 5 parts by mass of a pigment dispersant and an anti-settling agent as other additives were mixed, and the mixture was kneaded with a disperser to prepare an ink containing a high concentration of carbon black (containing a carbon black concentration of 35% by mass). black ink).

Next, 100 parts by mass of the above-mentioned polyester polyol resin solution, 64.4 parts by mass of ethyl acetate, and the required amount of the above-mentioned ink containing high-concentration carbon black were mixed, and a pigment dispersing machine was used to mix the ink containing carbon black. The ink is dispersed to obtain a main agent for an adhesive to which a color pigment (carbon black) is added. Furthermore, an adduct (NCO% 13.0%) of toluene diisocyanate (TDI) (aromatic) and trimethylolpropane as an aromatic isocyanate compound was added to 100 parts by mass of the main agent containing the color pigment. 7.1 parts by mass of solid content (75%) as a curing agent, and further blended with 34.1 parts by mass of ethyl acetate, and stirred sufficiently to obtain a colored adhesive composition. In this colored adhesive composition, the molar ratio (-NCO)/(-OH) of the isocyanate functional group (-NCO) and the polyester polyol hydroxyl group (-OH) is 10. As shown in Table 1, the pigment content concentration in the colored adhesive composition was 2.5% by mass.

A cured film (colored adhesive cured film) based on the above colored adhesive composition was produced, and the physical properties were evaluated. Specifically, the colored adhesive composition is applied to a non-adhesive untreated PP film so that the thickness after drying becomes 10 μm, the solvent is dried, and then aged and cured at 60° C. Residual isocyanate is 5% or less. The cured film was peeled off from the untreated PP film and cut into a width of 15 mm, and the resulting product was used as a test piece.

A tensile test was conducted on the prepared test piece under the conditions of a mark distance of 50mm and a tensile speed of 100mm/min to measure the Young's modulus, breaking strength and elongation at break. The results showed that the Young's modulus was 460MPa and the breakage The strength is 32MPa and the elongation at break is 23%. In addition, the S-S curve in this tensile test was obtained. As a result, the pattern was pattern A shown in FIG. 5 .

On the other hand, as the second adhesive layer, a polyacrylic adhesive was prepared, and as the sealant layer, an unstretched polypropylene film with a thickness of 30 μm was prepared.

In addition, as a matte coating, 70 parts by mass of fluoroethylene vinyl ester as a heat-resistant resin, 10 parts by mass of barium sulfate as inorganic fine particles, 10 parts by mass of powdered silica, and polytetrafluoroethylene as a wax were used. 5 parts by mass of vinyl wax and 5 parts by mass of polyethylene resin beads as resin beads were mixed to prepare a composition for matte coating.

A predetermined amount of the above-mentioned colored adhesive composition is applied to one surface (outer surface) of the aluminum foil for the metal foil layer with chemical conversion coatings formed on both surfaces and dried to form a first adhesive layer (colored adhesive composition). adhesive cured film). Table 1 shows the coating amount, number average molecular weight Mn, weight average molecular weight Mw, Mw/Mn, and carbon black content (coating amount) of the colored adhesive composition. Then, the film for the base material layer was bonded to the first adhesive layer, the base material layer was laminated, and the film was aged in a 60° C. environment for 5 days.

Next, the above-mentioned polyacrylic acid adhesive as a second adhesive layer is applied to the other surface (lower surface) of the metal foil layer, and the above-mentioned polyacrylic acid adhesive as a sealant layer is bonded to the lower surface (inner surface). Acrylic film.

Furthermore, the above-mentioned matte coating composition was applied to the outer surface of the base material layer so that the thickness after drying would become 2 μm.

The laminated body bonded as above was left to age in a 40° C. environment for 5 days, thereby obtaining the packaging material (outer packaging material for electrical storage devices) of Example 1.

<Examples 2 to 7 and Comparative Examples 1 to 4>

As shown in Table 1, in the first adhesive layer, the pigment concentration (carbon black concentration), the coating amount of the colored adhesive composition, the pigment coating amount (content), the number average molecular weight Mn, and the weight average molecular weight were adjusted Except for Mw and Mw/Mn, the same operation was performed as in Example 1 to obtain packaging materials of Examples 2 to 7 and Comparative Examples 1 to 5.

＜Evaluation test＞

(1) Evaluation of concealment (shielding)

Each packaging material of Examples and Comparative Examples was visually observed from the base material layer side (outer surface side) to confirm the concealment of the metal foil layer. Furthermore, the case with shielding properties was evaluated as "0", and the case without shielding properties was evaluated as "×". The evaluation results obtained as described above are shown in Table 1.

(2) Evaluation of formability

Made by AMADA CO., LTD., a mold having a punch shape of 33 mm × 54 mm, punch corner R: 2 mm, punch shoulder R: 1.3 mm, and die shape die shoulder R: 1 mm was prepared. Stamping machine.

Then, each packaging material of the Example and the Comparative Example was sampled in a blank shape of 100 mm × 125 mm, and each sample was deep-drawn using the above-mentioned press machine to produce a molded product sample.

The presence or absence of pinholes and cracks at the corner portions of each molded article obtained by the deep drawing molding was confirmed, and the "maximum molding depth (mm)" at which pinholes and cracks did not occur was determined based on the following criteria. evaluate. It should be noted that during evaluation, the presence of cracks and pinholes was inspected using the light transmission method in a dark room. Among the evaluation criteria "◎", "○" and "×" described below, "◎" and "○" indicate passing, and "×" indicates failure. The results are shown in Table 1.

◎: Molding depth is more than 6mm, no cracks or pinholes

〇: The molding depth is more than 5mm and less than 6mm, and there are no cracks or pinholes.

×: The molding depth is less than 5mm, there are cracks and pinholes

(3) Evaluation related to peeling

Each packaging material of the Examples and Comparative Examples was sampled in a predetermined size, and each sample was deep-drawn in the same manner as above. As shown in Figure 6, a depressed portion (convex portion) having 33mm×54mm×4.5mm was produced. ) 21, and a molded shell (a disc-shaped member turned upside down) 2 of a molded product having a flat flange portion 22 on the outer periphery of the convex portion. Furthermore, the molded article 2 was concavely deformed in such a manner that the top wall (top surface) 25 of the convex portion was crushed, and then the following high temperature and high humidity test and warm water immersion test were performed to determine whether there was a base material layer after the test. The peeling was visually observed.

In the high-temperature and high-humidity test, the molded article 2 with the top surface 25 crushed was stored for 2 weeks in an atmosphere with a temperature of 70° C. and a humidity of 90%, and the presence or absence of peeling of the base material layer was confirmed. In addition, in the warm water immersion test, the crushed molded article 2 was immersed in warm water at 45° C. and stored for 2 weeks.

In both tests, 30 molded products 2 for each of the Examples and Comparative Examples were visually observed, and based on the number of molded products 2 in which the base material layer was peeled off from the metal foil layer, evaluation was performed based on the following criteria. In addition, among the following evaluation criteria "◎", "○", "△" and "×", "◎", "〇" and "△" mean passing, and "×" means failing. The results are shown in Table 1.

◎: Out of 30 pieces, 0 molded products were peeled off.

○: Out of 30 pieces, 1 or 2 molded products were peeled off

△: Among 30 pieces, 3 to 5 molded products were peeled off

×: Out of 30 pieces, 6 to 30 pieces of molded products were peeled off

＜Comprehensive evaluation＞

From the above evaluation results, it can be seen that the packaging materials (outer packaging materials) of the Examples related to the present invention were evaluated as excellent in terms of shielding properties, moldability, and peeling resistance. On the other hand, compared with the packaging materials of Examples, the packaging materials of Comparative Examples, which are beyond the scope of the present invention, were inferior in all evaluations.

Industrial availability

The packaging material of the present invention can be suitably used as an outer packaging material for batteries (power storage equipment) such as notebook computers, mobile phones, vehicle-mounted type (mobile type) or stationary type secondary batteries (lithium ion secondary batteries). .

This application claims priority from Japanese Patent Application No. 2022-71704, filed on April 25, 2022, and Japanese Patent Application No. 2023-40851, filed on March 15, 2023, the disclosure contents of which are directly forms part of this application.

It should be understood that the terms and expressions used here are used for explanation and are not used for restrictive interpretation, nor do they exclude any equivalents of the features shown and described here, and are also allowed to fall within the scope of protection claimed by the present invention. various deformations.

Claims (11)

1. A packaging material comprising a metal foil layer laminated on the inside of a heat-resistant resin base material layer, and a thermoplastic resin sealant layer laminated on the inside of the metal foil layer, wherein the metal foil layer and a colored adhesive layer between the base material layers, characterized in that: The colored adhesive layer is composed of a colored adhesive cured film containing a colored pigment and an adhesive, The Young's modulus of the colored adhesive cured film according to the tensile test based on JIS K7161-1:2014 is 450 MPa to 700 MPa. 2. The packaging material according to claim 1, wherein the colored adhesive cured film has an elongation at break of 21% to 60% in a tensile test based on JIS K7161-1:2014. 3. The packaging material according to claim 1 or 2, wherein the colored adhesive layer contains 2 mass% or more and less than 5 mass% of the colored pigment, The colored adhesive layer is the colored adhesive cured film of 5g/m ² to 10 g/m ² . 4. The packaging material according to claim 1 or 2, wherein the adhesive of the colored adhesive layer contains a polyester resin as a main agent and a polyfunctional isocyanate compound as a curing agent. Two-liquid curable polyester urethane resin, The number average molecular weight (Mn) of the polyester resin as the main ingredient is 8,000 to 25,000, the weight average molecular weight (Mw) is 15,000 to 50,000, and their ratio (Mw/Mn) is 1.3 to 2.5. The polyfunctional isocyanate compound as a curing agent contains 50 mol% or more of aromatic isocyanate. 5. The packaging material according to claim 4, wherein in the two-liquid curable polyester urethane resin, the polyester resin as the main agent uses dicarboxylic acid and glycol as raw materials, The dicarboxylic acid includes an aliphatic dicarboxylic acid and an aromatic dicarboxylic acid having an even number of methylene groups in the methylene chain, and the content rate of the aromatic dicarboxylic acid relative to their total amount is 40 moles. %～80 mol%. 6. The packaging material according to claim 1 or 2, wherein the metal foil layer has a chemical conversion coating on at least one surface thereof. 7. The packaging material according to claim 1 or 2, wherein a matte coating is provided on the outer surface of the base material layer. 8. Packaging container, characterized in that the packaging material according to claim 1 or 2 is formed with a molded portion based on deep drawing molding or embossing molding. 9. An outer packaging material for electrical storage equipment, characterized in that it is composed of the packaging material according to claim 1 or 2. 10. Electric storage equipment, characterized by: The main body of the electrical storage equipment; and The outer packaging material according to claim 8, The main body of the electrical storage device is externally packaged using the external packaging material. 11. A method for producing a colored adhesive composition constituting a colored adhesive cured film in the packaging material according to claim 1 or 2, characterized in that: Mix the coloring pigment into the vehicle and prepare liquid colorant in advance, Mix the liquid colorant into the main agent and the curing agent constituting the adhesive to prepare a pigment-containing main agent for the adhesive, and then, The pigmented adhesive main agent and the curing agent are blended to produce the colored adhesive composition.