JP2001199413A - Heat seal method for container, and container for battery manufactured by using the heat seal method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a heat seal method for a container to further improve the steam barrier property of the container using a laminate film containing an aluminum foil in an intermediate layer, and the container for a battery having the excellent steam barrier property using the heat seal method. SOLUTION: When heat-sealing an edge of the container formed of the laminate film in which a base layer, the aluminum foil layer, and a heat-bonding resin layer are laminated from the outside in this order with a predetermined width, the edge is beat-sealed to at least one of seal heads using the seal head having a step in which the height is changed in an intermediate portion in the seal width, and an outer portion is high and an inner portion is low so that the heat-bonding resin layer of the outer portion is thinner than that on the inner portion. The heat seal is preferably implemented so that the heat- bonding resin layer on the outer portion is thinner than that of the inner portion by 30-70%, and the seal width of the outer portion is wider than that of the inner portion.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for heat-sealing a container and a battery container manufactured by using the heat-sealing method, and more particularly, to a bag type or a flange formed by heat-sealing a laminated film. When a high degree of water vapor or other barrier properties are required in a container such as a tray that combines a shallow tray with a seal lid, water vapor permeation from the end face of the heat seal portion at the container edge, which is a weak point, is likely to be a weak point And a battery container having a high degree of water vapor and other barrier properties produced by using the heat sealing method.

[0002]

2. Description of the Related Art Conventionally, when a container of a bag type using a laminated film or a tray type in which a shallow tray with a flange and a sealing lid are combined is required to have a high level of steam and other barrier properties. ,Normally,
As a laminated film, for example, a configuration in which a base layer, an aluminum foil layer, a thermoadhesive resin layer, and the like are sequentially laminated from the outside, that is, a configuration in which a high barrier material such as an aluminum foil is laminated on an intermediate layer or the like. Using a film,
A method for improving the barrier property has been adopted.

[0003] However, when a container is formed using the laminated film having such a structure, water vapor and other barrier properties from the wall surface can be made almost perfect. At the end face of the portion, for example, at least a heat-adhesive resin layer was interposed between the aluminum foil layers on both sides, so that the inside and outside of the container could not be completely shut off by the aluminum foil layer.

[0004] Therefore, there is a slight problem that moisture infiltrates from between the aluminum foil layers on both sides of the end face of the heat seal portion. For example, the container is used for chemicals, polymer batteries, and especially lithium polymer batteries. In the case of containers that require a high degree of water vapor or other barrier properties over a long period of time, such as for use, this cannot be ignored.

[0005] As for the intrusion of moisture from the end face of the heat seal portion, a layer interposed between the aluminum foil layers on both sides, for example, an intermediate layer for protecting the inside of the aluminum foil, a heat-adhesive resin, or the like. Layers, and materials such as an adhesive layer for dry lamination for laminating them, that is, their water vapor permeability, and their thickness, as well as their length, which serves as a moisture entry path, that is, heat The width of the seal portion is related.

In order to minimize the intrusion of moisture from the end face of the heat seal portion, a layer other than the minimum necessary heat-adhesive resin layer, that is, the aluminum It is preferable to remove as much as possible the intermediate layer or adhesive layer that protects the inside of the foil, and it is also preferable to make the thickness of the heat-adhesive resin layer as thin as possible.
Further, it is preferable that the width of the heat seal portion is as large as possible.

However, among the above, the heat seal width is limited due to the shape of the container and the material cost, and there is a limit in increasing the heat seal width more than necessary. Therefore, from between the aluminum foil layers on both sides, the intermediate layer and the adhesive layer are removed as much as possible, and the thickness of the heat-adhesive resin layer is set to be thin to constitute a laminated film. At the time of heat sealing, the heat-adhesive resin layer of the heat-sealed portion is compressed, and its thickness is, for example, 70 to 30 times the original thickness.
% Heat seal was attempted.

[0008]

By adopting such a heat sealing method, the cross-sectional area between the aluminum foil layers on both sides of the end face of the heat seal portion can be reduced, and the edge of the container can be surely reduced. Thus, permeation of water vapor from the end face of the heat seal portion was reduced, and the water vapor and other barrier properties of the container could be improved. However, when such a heat sealing method is adopted, the barrier property of water vapor and the like of the container can be improved, but the thickness of the heat-adhesive resin layer in the heat seal portion at the edge of the container suddenly becomes thin. Therefore, at the boundary between the heat-sealed portion and the inside thereof, that is, at the portion along the inner line of the heat-sealed portion, the heat-adhesive resin layer is liable to cause a so-called edge cut phenomenon, and as a result, the heat-sealing strength is reduced. There was a problem to do.

The present invention has been made in order to solve such a problem, and an object of the present invention is to provide a barrier layer such as an aluminum foil layer in an intermediate layer, and at least a heat transfer layer in an innermost layer. A heat-sealing method for heat-sealing an edge portion of a container formed of a laminated film in which an adhesive resin layer is laminated, wherein the thickness of the heat-adhesive resin layer between the aluminum foil layers on both sides by heat sealing. To
It can be thinner than the original thickness, that is, it can reduce the permeation of water vapor into the container from the end face of the heat seal part, and also reduce the heat seal strength, which is the original function. In addition to providing a heat-sealing method for containers that can perform good heat-sealing, and by using the heat-sealing method, as a moisture-proof container for ordinary use, from the beginning, especially high-level steam and other barrier properties It is an object of the present invention to provide a battery container which can be suitably used for a container such as a lithium polymer battery which requires the above.

[0010]

The above objects can be achieved by the present invention described below. That is, the invention described in claim 1 forms a laminated film in which a base material layer, an aluminum foil layer, and a thermoadhesive resin layer are sequentially laminated at least from the outside so that the thermoadhesive resin layers face each other. A method for heat-sealing a container formed by arranging and heat-sealing the edges thereof, and when heat-sealing the edge of the container with a predetermined seal width, at least one of the seal heads on both sides. On the other hand, heat sealing is performed using a seal head provided with a step in which the height changes at an intermediate portion of the seal width, the outer portion is high, and the inner portion is low, and heat is applied to a predetermined width of an edge portion of the container. The heat sealing method for a container is characterized in that heat sealing is performed so that the thickness of the heat-adhesive resin layer at the outer portion of the seal portion is smaller than the thickness of the heat-adhesive resin layer at the inner portion.

[0011] By employing such a heat sealing method, the heat-adhesive resin layer is entirely compressed at the heat seal portion at the edge of the container and heat-sealed so as to be thinner than the original thickness. Even in such a case, the thickness of the heat-adhesive resin layer in the inner portion of the heat-sealed portion becomes thinner than that of the outer portion. However, it is possible to prevent a decrease in heat seal strength due to the cut edge, and to further reduce the distance between the aluminum foil layers on both sides at the outer portion of the heat seal portion, so that the edge of the container The water vapor permeation from the heat seal end face of the portion can be further reduced.

According to a second aspect of the present invention, in the heat seal portion having the predetermined width, the thickness of the outer portion of the heat-adhesive resin layer is 30 to 70 times larger than the thickness of the inner portion of the heat-adhesive resin layer. %
The method for heat-sealing a container according to claim 1, wherein the heat-sealing is performed so as to be thin.

The range in which the thickness of the heat-adhesive resin layer on the outer side is made smaller than the thickness of the heat-adhesive resin layer on the inner side is 30
About 70% is appropriate. When the above value is less than 30%, that is, when the thickness of the outer thermoadhesive resin layer exceeds 70% of the thickness of the inner thermoadhesive resin layer, a sufficient moisture-proofing effect is not obtained. It is not preferable because it cannot be obtained,
When the above value exceeds 70%, that is, the thickness of the heat-adhesive resin layer on the outer side is 3 times the thickness of the heat-adhesive resin layer on the inner side.
If it is less than 0%, the effect of improving the moisture resistance is sufficiently obtained, but the heat sealing strength may be reduced, which is not preferable.

Therefore, by adopting the heat sealing method as described above, the thickness of the heat-adhesive resin layers at the inner and outer portions of the heat-sealed portion having the predetermined width at the edge of the container is appropriately adjusted. Since the thickness can be gradually reduced while being adjusted, in addition to the operation and effect of the invention described in claim 1, the steam and other barrier properties of the container can be more effectively improved without lowering the heat seal strength. be able to.

According to a third aspect of the present invention, in the heat seal portion having the predetermined width, a seal width of an outer portion is formed to be wider than a seal width of an inner portion. 2. The method for heat sealing a container according to item 2.

In the heat-sealed portion having the predetermined width, an inner portion prevents an edge-cutting phenomenon that occurs when the heat-sealed portion is compressed and the heat-adhesive resin layer of the laminated film becomes thin, and the heat-sealing strength is reduced. In order to prevent this, the thickness of the heat-adhesive resin layer is provided to be thicker than that of the outer portion, and the outer portion is provided with a heat-adhesive resin layer so that the moisture-proof property can be effectively improved at this portion. Is made as thin as possible. Therefore, the width of the seal at the inner portion may be narrow as long as the edge breakage phenomenon can be prevented, and about 1.5 to 3 mm is sufficient. In this regard, the wider the seal width of the outer part, the better the moisture resistance can be improved.
Unless otherwise hindered, it is preferable to widen the width.

Therefore, by adopting the heat sealing method as described above, in addition to the functions and effects of the invention described in claim 1 or 2, water vapor and the like in the container can be more effectively reduced without lowering the heat sealing strength. Can be improved in barrier properties.

According to a fourth aspect of the present invention, a laminated film in which a base material layer, an aluminum foil layer, and a thermo-adhesive resin layer are laminated in this order from at least the outside is formed so that the thermo-adhesive resin layers face each other. And a container formed by heat-sealing the edges of the container, when the edge of the container is heat-sealed with a predetermined seal width, at least one of the seal heads on both sides. Then, heat sealing is performed using a seal head provided with a step in which the height changes at an intermediate portion of the seal width, the outer portion is high, and the inner portion is low, and the heat seal of a predetermined width at the edge portion of the container is performed. Out of the department
The battery container is characterized by being heat-sealed such that the thickness of the heat-adhesive resin layer on the outer portion is smaller than the thickness of the heat-adhesive resin layer on the inner portion.

By adopting such a configuration, even when the heat-adhesive resin layer is entirely compressed at the heat seal portion at the edge of the container and heat-sealed so as to be thinner than the original thickness. Of the heat seal width, the inner portion is thicker than the outer portion, so that the thickness of the heat adhesive resin layer does not suddenly decrease in the heat seal portion. Therefore, it is possible to prevent a decrease in heat seal strength due to the edge cut, and to further reduce the distance between the aluminum foil layers on both sides in the outer portion of the heat seal portion. Water vapor permeation from the end face of the heat seal portion is further reduced, so that a battery container which is excellent in heat seal strength and further excellent in steam and other barrier properties can be provided.

According to a fifth aspect of the present invention, in the heat-sealed portion having the predetermined width, the thickness of the outer thermoadhesive resin layer is 30 to 70% of the thickness of the inner thermoadhesive resin layer. The battery container according to claim 4, wherein the container is heat-sealed so as to be thin.

The range in which the thickness of the outer thermoadhesive resin layer is smaller than the thickness of the inner thermoadhesive resin layer is suitably about 30 to 70% as described above. When the above value is less than 30%, that is, when the thickness of the outer thermoadhesive resin layer exceeds 70% of the thickness of the inner thermoadhesive resin layer, a sufficient moisture-proofing effect is not obtained. It is not preferable because it cannot be obtained, and when the above value exceeds 70%, that is, when the thickness of the heat-adhesive resin layer on the outer side is less than 30% of the thickness of the heat-adhesive resin layer on the inner side. Although the effect of improving the moisture-proof property can be sufficiently obtained, there is a possibility that the heat sealing strength may be reduced, which is not preferable.

Therefore, by adopting the above-described configuration, the thickness of the heat-adhesive resin layer at the inner and outer portions of the heat-sealed portion having the predetermined width at the edge of the container is appropriately adjusted. In addition to the functions and effects of the invention described in the fourth aspect, the present invention provides a battery container that is more excellent in water vapor and other barrier properties without lowering the heat seal strength, since the thickness can be reduced stepwise. Can be.

According to a sixth aspect of the present invention, in the heat seal portion having the predetermined width, an outer portion has a wider seal width than an inner portion. 6. The battery container according to 4 or 5.

In the heat seal portion having the predetermined width, as described above, the inner portion prevents the edge cut phenomenon that occurs when the heat seal portion is compressed and the heat adhesive resin layer of the laminated film becomes thin. And, it is provided to prevent a decrease in heat seal strength, and is provided so that the thickness of the heat-adhesive resin layer is thicker than the outer portion, and the outer portion is effectively formed at this portion. In order to improve the moisture-proof property, the thickness of the heat-adhesive resin layer is provided as thin as possible. Therefore, the width of the seal at the inner portion may be narrow as long as the edge breakage phenomenon can be prevented, and usually about 1.5 to 3 mm is sufficient, and the wider the seal width at the outer portion, the better the moisture resistance. It is preferable to make it as wide as possible.

Therefore, by adopting the above configuration, in addition to the functions and effects of the invention described in claim 4 or 5, the battery is excellent in heat seal strength and further excellent in steam and other barrier properties. Container can be provided.

[0026]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of a container heat sealing method of the present invention and a battery container manufactured by using the heat sealing method will be described. First, the container heat sealing method of the present invention, as described above, at least from the outside, a substrate layer, an aluminum foil layer,
A laminated film in which a heat-adhesive resin layer is sequentially laminated,
A method for heat-sealing a container formed by arranging the heat-adhesive resin layers to face each other and heat-sealing the edges thereof, wherein the edge of the container is heated with a predetermined sealing width. When sealing, at least one of the seal heads on both sides, the height changes in the middle of the seal width,
Heat sealing is performed using a seal head provided with a step in which the outer portion is high and the inner portion is low, and the thickness of the heat-adhesive resin layer on the outer portion of the heat-sealed portion having a predetermined width at the edge portion of the container. Is heat-sealed such that the thickness is smaller than the thickness of the heat-adhesive resin layer on the inner side,
Further, of the heat-sealed portion having the predetermined width, heat-sealing such that the thickness of the heat-adhesive resin layer at the outer portion is 30 to 70% smaller than the thickness of the heat-adhesive resin layer at the inner portion; And forming the outer portion of the heat seal portion having the predetermined width to be wider than the inner portion of the heat seal portion.

The form of the container to which such a heat sealing method is applied is not particularly limited, and is, for example, a bag-type container such as a three-side seal type, a four-side seal type, a pillow pouch type, a gusset pouch type, and a standing pouch type. In addition, a tray-type container in which a shallow tray with a flange formed by press-molding a laminated film or the like and a seal lid may be combined. When the edge of such a container is heat-sealed by the heat-sealing method as described above, for example, a shim having a predetermined thickness is provided on both sides between the upper and lower seal heads of the heat-sealing device. By heat-sealing by mechanically controlling the clearance such as by inserting a heat-sealing resin layer on the inner and outer sides of the heat-sealed portion having the predetermined width, the thickness of the heat-adhesive resin layer can be more reliably reduced to a desired thickness. Can be adjusted.

Also, when a battery container is manufactured by using such a heat sealing method, the material of the container is as follows.
A laminated film having a configuration in which a base material layer, an aluminum foil layer, and a thermoadhesive resin layer are sequentially laminated at least from the outside can be used. The outermost substrate layer is not particularly limited, but is preferably a biaxially oriented polyethylene terephthalate film, a biaxially oriented polyethylene naphthalate film, a biaxially oriented polybutylene terephthalate film, or a biaxially oriented film having various strengths and durability. A single film such as a biaxially oriented polyester film such as a polybutylene naphthalate film or a biaxially oriented nylon film, or a laminated film obtained by laminating two or more of these films by a dry lamination method or the like can be used.

The aluminum foil layer of the intermediate layer is to be laminated in order to impart water vapor and other barrier properties to the container, and a soft aluminum foil is suitable. % By weight, more preferably 0.7-2.
Aluminum foil containing 0% by weight is preferable because it has better spreadability and can reduce the occurrence of pinholes and the like even when subjected to processing such as bending or press molding.

When the container is used as a battery container, especially a lithium polymer battery container, when moisture enters the container, it reacts with the electrolyte to generate hydrogen fluoride, and the aluminum foil layer is corroded. There's a problem. Therefore, it is preferable that the aluminum foil layer has an improved surface resistance to hydrogen fluoride. For this reason, it is preferable that at least the inner surface or both surfaces of the aluminum foil layer be subjected to a chromate treatment. In the chromate treatment, for example, an aqueous solution of a phenol resin, phosphoric acid, and chromium (III) compound is applied by a roll coating method or the like, and then the aluminum foil is heated to a temperature of 170 to 200 ° C. to form a film. It is to let. By performing such a chromate treatment on the surface of the aluminum foil layer, it is possible to improve the resistance to hydrogen fluoride, acid, and the like, and also to improve the adhesiveness of the surface. There is also obtained an advantage that the lamination strength when laminating the base material layers can be improved.

Various polyolefin-based resins can be used for the innermost heat-adhesive resin layer. When the container is a battery container, the heat-adhesiveness, moisture-proofness, and content resistance, that is, It is necessary to have resistance to an electrolytic solution containing an electrolyte, etc., and polypropylene or acid-modified polypropylene is suitable. These may be used alone or may be used by appropriately laminating them. When both are used by laminating, in addition to the two layers of a polypropylene layer and an acid-modified polypropylene layer, for example, an intermediate layer is made a polypropylene layer, and an acid-modified polypropylene layer is laminated on both sides thereof.
It may have a layer structure.

Since the acid-modified polypropylene is excellent in heat adhesion to metal in addition to self-adhesion to itself, the heat-adhesive resin layer is coated on the inside of the aluminum foil layer by a heat lamination method or an extrusion coating method. In the case of lamination, the adhesiveness is good. For example, when the electrode terminals are provided extending from the inside of the battery container to the outside, even if the surface (adhesion surface) of the electrode terminals is bare metal, At the edge of the container, it can be well heat bonded and sealed. Which of the thermo-adhesive resin layers to choose, the lamination method, the material of the adhesive surface of the electrode terminal,
For example, it is preferable to appropriately select and laminate a suitable material depending on whether the surface is coated or bare metal.

Examples of the acid-modified polypropylene include graft polymerization modified with unsaturated carboxylic acids such as acrylic acid, methacrylic acid, maleic acid, maleic anhydride, citraconic anhydride, itaconic acid, and itaconic anhydride, or anhydrides thereof. Polypropylene or a polypropylene blended with a polyolefin resin copolymerized with the acid component can be used. These may be used alone or as a blend of two or more.

In the method of laminating each layer as described above, regarding the lamination of the base material layer and the aluminum foil layer, both are supplied in the form of a film, that is, in the form of a long roll, so that the two-component curing type is used. Lamination can be performed without any problem by a known dry lamination method using a polyurethane adhesive or the like.
Further, regarding the lamination of the aluminum foil layer and the heat-adhesive resin layer, by forming the heat-adhesive resin layer into a film in advance, a dry lamination method using the adhesive,
Alternatively, without using an adhesive, it can be laminated by a method of laminating by heating and pressing called a thermal lamination method, or it can be laminated by extruding a thermo-adhesive resin to an inner surface of an aluminum foil layer by an extrusion coating method. .

In the case of laminating a heat-adhesive resin layer by the above-mentioned thermal lamination method or extrusion coating method, a pretreatment such as a known anchor coat or primer coat can be applied to the laminated surface of the aluminum foil layer, if necessary. . When applying a primer coat, when using a polypropylene or an acid-modified polypropylene for the heat-adhesive resin layer, it is preferable to use a primer coat using a resin of the same type.For example, a dispersion or solution of an acid-modified polypropylene is laminated with an aluminum foil layer. A suitable method is to coat the surface thinly, dry it, heat it to a high temperature of 170 to 200 ° C., fuse it, and form a film.

Of the three methods of laminating an aluminum foil layer and a heat-adhesive resin layer, the dry lamination method has a relatively high hygroscopicity of the adhesive and a thickness of about 2 to 3 μm. However, although the adhesive layer is thin, two adhesive layers are interposed between the aluminum foil layers on both sides in the heat seal portion at the edge of the container, which is not preferable in that the moisture resistance of the battery container is reduced. Therefore, in consideration of both the moisture-proof property and the lamination strength, the thermal lamination method was the best of the three methods.

Hereinafter, typical specific examples of the constitution of the laminated film used in the present invention will be shown. However, pretreatment such as chromate treatment of aluminum foil is omitted. (1) PET film layer / adhesive layer / aluminum foil layer /
Acid-modified PP primer layer / unstretched PP film layer (innermost layer) (2) PET film layer / adhesive layer / aluminum foil layer /
Acid-modified PP primer layer / unstretched acid-modified PP film layer (innermost layer) (3) PET film layer / adhesive layer / aluminum foil layer /
Acid-modified PP primer layer / coextruded film layer (PP
Layer / acid-modified PP layer) (innermost layer) (4) PET film layer / adhesive layer / aluminum foil layer /
Acid-modified PP primer layer / co-extruded film layer (acid-modified PP layer / PP layer / acid-modified PP layer) (innermost layer) (5) ON film layer / adhesive layer / aluminum foil layer / acid-modified PP primer layer / none Stretched PP film layer (innermost layer) (6) ON film layer / adhesive layer / aluminum foil layer / acid-modified PP primer layer / non-stretched acid-modified PP film layer (innermost layer) (7) ON film layer / adhesive layer / Aluminum foil layer / acid-modified PP primer layer / co-extruded film layer (PP layer / acid-modified PP layer) (innermost layer) (8) ON film layer / adhesive layer / aluminum foil layer / acid-modified PP primer layer / Extruded film layer (acid-modified PP layer / PP layer / acid-modified PP layer) (innermost layer) (9) PET film layer / adhesive layer / ON film layer / adhesive layer / aluminum foil layer / acid-modified PP primer layer /
Unstretched PP film layer (innermost layer) (10) PET film layer / adhesive layer / ON film layer / adhesive layer / aluminum foil layer / acid-modified PP primer layer /
Non-stretched acid-modified PP film layer (innermost layer) (11) PET film layer / adhesive layer / ON film layer / adhesive layer / aluminum foil layer / acid-modified PP primer layer /
Co-extruded film layer (PP layer / acid-modified PP layer) (innermost layer) (12) PET film layer / adhesive layer / ON film layer / adhesive layer / aluminum foil layer / acid-modified PP primer layer /
Examples of the configuration include a co-extruded film layer (acid-modified PP layer / PP layer / acid-modified PP layer) (innermost layer), but the present invention is not limited thereto, and various configurations can be adopted.

In the above, all the adhesive layers are adhesives for dry lamination, the PET film is a biaxially stretched polyethylene terephthalate film, and the ON film is
The axially stretched nylon film, PP indicates polypropylene, and the innermost coextruded film is a non-stretched film. And acid-modified P inside the aluminum foil layer
The lamination of the innermost layer to the P primer layer, that is, the lamination of various thermo-adhesive resin film layers is performed by a thermal lamination method.

[0039]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described more specifically with reference to the drawings. However, the present invention is not limited to these drawings. FIG. 1 is a view for explaining one embodiment of the method for heat sealing a container of the present invention, and is a partially enlarged cross-sectional view of a seal head of a heat sealing device and a heat seal portion of the container. The method of heat sealing a container shown in FIG. 1 is based on the upper seal head 1a mounted on the heat sealing device.
And the lower seal head 1b, the edge of the container to be heat-sealed is inserted between the upper and lower seal heads 1a.
, 1b are heat-pressed for a predetermined time to perform heat sealing. In this case, the tip (the upper end in the figure) of the lower seal head 1b is flat, but the tip (the lower end in the figure) of the upper seal head 1a is located at the middle part of the entire width w of the heat seal portion. change the height, the part of the seal width w ₂ of the outer part high height h _2, portions of the seal width w ₁ of the inner portion has a height h ₁ is provided with a step to be low.

In the above, the total width w of the heat seal portion is
Is usually about 5 to 10 mm, and the seal width w of the inner portion is
₁ is a sufficient 1.5 to 3 mm, it can be the remaining width seal width w ₂ of the outer part. The seal width w ₂ of the outer portion is preferably larger than the seal width w ₁ of the inner portion. The specific value of the step (h ₂ −h ₁ ) at the tip of the upper seal head 1 a is not constant because it varies depending on the thickness of the heat-adhesive resin layer of the laminated film, but is about 30 to 70 μm. Is suitable, whereby the thickness t ₂ of the heat-adhesive resin layer in the outer seal width w ₂ portion of the heat seal portion having the predetermined width w at the edge of the container is
The thickness t of the heat-adhesive resin layer of the seal width w ₁ of the portion of the inner portion
It can be 30-70% thinner than ₁ . Strictly speaking, t ₁ and t ₂ are distances between the aluminum foil layers on both sides. However, even when a primer coat or the like is used, the thickness is extremely thin. Equivalent to.

The container to be heat-sealed is formed of a laminated film 2 in which a substrate layer 3, an aluminum foil layer 4, and a heat-adhesive resin layer 5 are laminated in this order from at least the outside.
The laminated film 2 is arranged so that the heat-adhesive resin layers 5 are opposed to each other, and the edges of the laminated films 2 are arranged at the upper and lower seal heads 1a,
The container can be manufactured by a method of heat sealing by inserting between b. At the time of the above-mentioned heat sealing, although not shown in the figure, as described above, a predetermined thickness of shim is inserted into both sides between the upper and lower seal heads to adjust the compression amount to a predetermined value, whereby Thicknesses t ₁ and t of the heat-adhesive resin layers at the inner and outer portions of the heat seal portion having a width.
₂ can be more reliably adjusted to a desired thickness.

By heat-sealing the edge of the container by such a heat-sealing method, the heat of the predetermined width w of the edge of the container is adjusted according to the shape of the upper seal head 1a having a step at the tip. sealing portion, and the seal width w ₁ of the portion of the inner part, is compressed into a shape having a step between the seal width w ₂ of the portions of the outer portion, the thickness of the heat-adhesive resin layer of each portion, step The distance between the aluminum foil layers on both sides is reduced to t ₁ at the seal width w _{1 at} the inner portion, and further reduced to t ₁ at the seal width w _{2 at} the outer portion.
Reduced to ₂ . In this case, the thickness t ₂ of the heat-adhesive resin layer in a portion of the seal width w ₂ of the outer portion is thinner than 30% to 70% of the thickness of this portion of the pre-heat-sealed.

Accordingly, the distance between the aluminum foil layers on both sides of the outer portion of the heat seal portion at the edge of the container is greatly reduced, and the area between the aluminum foil layers on both sides of the end face of the heat seal portion is also significantly reduced. Therefore, the permeation of water vapor from this portion is further reduced, and the water vapor and other barrier properties of the container can be greatly improved. In addition, since the thickness of the heat-adhesive resin layer does not suddenly decrease in the inner line portion of the heat seal portion, it is possible to prevent a decrease in heat seal strength due to an edge cut phenomenon, and to provide a good heat seal strength. Can be maintained.

In FIG. 1, the upper and lower seal heads 1a,
1b, only one of the seal heads, that is, the upper seal head 1a is provided with a height difference (step), but the height of both seal heads is, for example, vertically symmetrical. A difference (step) can be provided. In this case, the difference in height (step) may be １ ／ of that in the case of only one side.

FIG. 2 is a schematic plan view showing the structure of an embodiment of a battery container manufactured by using the container heat sealing method of the present invention. The battery container 100 shown in FIG.
For example, from the outside, using a laminated film 2 in which a base material layer, an aluminum foil layer, and a thermoadhesive resin layer are sequentially laminated, and after being folded in two at the folded portion 6 such that the thermoadhesive resin layers face each other, In the figure, the right side portion and the bottom edge portion are heat-sealed by the heat-sealing method shown in FIG. 1 so that the outer heat-seal portion 7b of the predetermined-width heat-seal portion 7 has the inner heat-seal portion 7a. And the outer heat-seal portion 7b is more strongly compressed than the inner heat-seal portion 7a, and the thickness of the heat-adhesive resin layer is increased from the inside of the container to the inner heat-seal portion 7a and the outer heat-seal portion. Heat sealing so that the heat sealing portion 7b is gradually thinned in this order;
It is configured as a bag-like container with an open top.

The upper opening receives the battery material in a bag-like container and extends the positive and negative electrode terminals from the inside to the outside through the opening. In the same manner as in the side and bottom heat seal portions 7, the thickness of the heat adhesive resin layer in the outer heat seal portion is
Heat sealing is performed so as to be thinner than the thickness of the heat-adhesive resin layer in the inner heat seal portion. At this time, for example, the heat-sealed portion of the electrode terminal is coated with an acid-modified polypropylene, so that the heat-sealing of the electrode terminal and the acid-modified polypropylene, and between the acid-modified polypropylene and the heat-adhesive resin layer are performed. Good adhesion can be achieved.

By adopting such a configuration, the heat-adhesive resin layer is entirely compressed in the heat-sealed portion at the edge of the container and heat-sealed so as to be much thinner than the original thickness. Even in such a case, the thickness of the heat-adhesive resin layer in the inner part of the heat-sealing width is thicker than that of the outer part. Without decreasing the thickness, it is possible to prevent a decrease in heat seal strength due to the edge cut, and, in the outer portion of the heat seal portion, since the distance between the aluminum foil layers on both sides can be significantly reduced, Provided is a battery container in which the water vapor permeation from the heat seal portion end face at the edge of the container is further reduced, the heat seal strength is excellent, and the water vapor and other barrier properties are further excellent. Door can be.

FIG. 3 is a schematic plan view showing the structure of an example of a battery manufactured using the battery container of the present invention. FIG.
2 is a battery container 1 shown in FIG.
This thin battery 500 is, for example, a battery container 100 shown in FIG. 2 and a battery material is inserted through an opening at an upper portion thereof. After extending the positive and negative electrode terminals 9a and 9b from the inside to the outside through the opening, the opening is formed into the inner sealing portion 7a and the outer sealing portion similarly to the side and bottom heat sealing portions 7. 7b can be manufactured by heat sealing into a shape having a step. By adopting such a configuration, the battery 500 has a heat-sealed portion at an edge thereof having good heat-sealing strength, and at the same time, water vapor transmission from the end face of the heat-sealed portion is significantly reduced. It has excellent moisture resistance and long-term stability.

[0049]

As described above in detail, according to the present invention, a laminated film comprising a substrate layer, an aluminum foil layer, and a thermo-adhesive resin layer laminated in this order from at least the outer side is obtained. Arranged so that the layers face each other,
A method for heat-sealing a container formed by heat-sealing the edges thereof, which can provide good heat-sealing strength and reduce water vapor transmission from the end face of the heat-sealed portion at the edge of the container. A heat-sealing method for a container capable of providing good heat-sealing strength, and at the same time, having a high degree of water vapor and other barrier properties by producing a container using the heat-sealing method. In addition, there is an effect that a battery container that can be suitably used also as a container for a lithium polymer battery or the like can be easily provided.

[Brief description of the drawings]

FIG. 1 is a view for explaining one embodiment of a method for heat sealing a container of the present invention, and is a partially enlarged cross-sectional view of a seal head of a heat sealing device and a heat seal portion of the container.

FIG. 2 is a schematic plan view showing the configuration of an embodiment of a battery container manufactured by using the container heat sealing method of the present invention.

FIG. 3 is a schematic plan view showing a configuration of an example of a battery manufactured using the battery container of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1a, 1b Seal head 2 Laminated film 3 Base layer 4 Aluminum foil layer 5 Thermal adhesive resin layer 6 Folded part 7 Heat seal part 7a Inner part heat seal part 7b Outer part heat seal part 8 Opening heat seal part 9a, 9b heat-sealed portion of the seal width t ₁ inner portion of the seal width w ₂ outer portion of the total width w ₁ inner portion of the height w heat-sealed portion of the sealing head height h ₂ high portion of the seal head of the electrode terminal h ₁ less portion thickness 100 battery container 500 cell thickness of the heat-adhesive resin layer is t ₂ outer part heat-adhesive resin layer of the heat-sealed portion of the

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification code FI Theme coat ゛ (Reference) B29L 22:00 B29L 22:00 (72) Inventor Kazuki Yamada 1-1-1 Ichigaya Kagamachi, Shinjuku-ku, Tokyo No. Within Dai Nippon Printing Co., Ltd. (72) Inventor Rikiya Yamashita 1-1-1, Ichigaya Kagacho, Shinjuku-ku, Tokyo F-term within Dai Nippon Printing Co., Ltd. 3E064 BA17 BA22 BB03 BC18 FA01 3E094 AA12 BA20 CA06 DA06 GA03 HA08 4F211 AD03 AD04 AD08 AD20 AG03 AG07 AH54 AH81 TA04 TC18 TD11 TN43 TN58 TQ01 5H011 AA10 CC10 DD13 FF02 GG09 HH13 KK01 KK02

Claims (6)

[Claims] 1. A laminated film in which a base material layer, an aluminum foil layer and a thermoadhesive resin layer are laminated in this order from at least the outside, so that the thermoadhesive resin layers face each other, A method for heat-sealing a container formed by heat-sealing portions of the container, wherein when heat-sealing an edge portion of the container with a predetermined seal width, at least one of the seal heads on both sides has the seal width. Heat sealing using a seal head provided with a step where the height changes at the middle part of the container, the outer part is higher, and the inner part is lower, and the outer part of the heat sealing part having a predetermined width at the edge of the container is A method for heat-sealing a container, characterized in that heat-sealing is performed so that the thickness of the heat-adhesive resin layer at the portion is smaller than the thickness of the heat-adhesive resin layer at the inner portion. 2. The heat-sealing portion having a predetermined width, wherein the thickness of the heat-adhesive resin layer on the outer portion is 30 to 70% smaller than the thickness of the heat-adhesive resin layer on the inner portion. The method for heat-sealing a container according to claim 1, wherein 3. The container according to claim 1, wherein, of the heat-sealed portions having the predetermined width, the outer portion has a wider seal width than the inner portion. Sealing method. 4. A laminated film comprising a base material layer, an aluminum foil layer, and a thermo-adhesive resin layer laminated in this order from at least the outside, so that the thermo-adhesive resin layers face each other, A container formed by heat-sealing the portions, when the edge of the container is heat-sealed with a predetermined seal width, at least one of the seal heads on both sides,
The height is changed in the middle part of the seal width, the outside part is high, and the inside part is heat-sealed using a seal head provided with a step where the inside part is low. The battery container is heat-sealed such that the thickness of the heat-adhesive resin layer at the outer portion is smaller than the thickness of the heat-adhesive resin layer at the inner portion. 5. The heat-sealed portion having a predetermined width is heat-sealed such that the thickness of the outer thermo-adhesive resin layer is 30 to 70% smaller than the thickness of the inner thermo-adhesive resin layer. The container for a battery according to claim 4, wherein: 6. The battery according to claim 4, wherein a seal width of an outer portion of the heat seal portion having the predetermined width is formed to be wider than a seal width of an inner portion. Container.