CN107310232B

CN107310232B - Laminate for battery exterior packaging, method for producing battery exterior packaging, and battery

Info

Publication number: CN107310232B
Application number: CN201611046622.3A
Authority: CN
Inventors: 武井邦浩; 丸山悠以子; 饭塚宏和
Original assignee: Fujimori Kogyo Co Ltd
Current assignee: Fujimori Kogyo Co Ltd
Priority date: 2016-04-26
Filing date: 2016-11-23
Publication date: 2020-09-18
Anticipated expiration: 2036-11-23
Also published as: KR101868804B1; JP2017199514A; JP6721400B2; KR20170122086A; TWI712201B; TW201739084A; CN107310232A

Abstract

The present invention provides a laminate for battery exterior packaging, which has excellent various characteristics and has good operation efficiency and yield when the laminate for battery exterior packaging is used for preparing a battery exterior packaging. The laminate for battery exterior packaging is characterized in that the sealant layer (11) is composed of block polypropylene, random polypropylene and olefin elastomer, the content ratios of the block polypropylene, random polypropylene and olefin elastomer in mass ratio are respectively A, B, C, and when the melting points of the block polypropylene, random polypropylene and olefin elastomer are respectively mpA, mpB and mpC, the sealant layer satisfies the relationships of the following expressions (1) to (4): a > B (1); a > C (2); a + B + C ═ 100 (3); mpA > mpB ≧ mpC (4).

Description

Laminate for battery exterior packaging, method for producing battery exterior packaging, and battery

Technical Field

The present invention relates to a laminate for battery exterior packaging that is excellent as an exterior packaging for a secondary battery, a capacitor, or the like, a battery exterior packaging obtained using the laminate, a method for producing the battery exterior packaging, and a battery provided with the battery exterior packaging.

Background

The present invention relates to a power storage device, and more particularly, to a power storage device that stores electric energy, and that stores electric energy.

For the purpose of downsizing and weight reduction, a laminate for battery exterior packaging in which a metal foil and a resin layer are laminated can be used as an exterior packaging body used for these batteries. Such a battery exterior laminate is formed into a disk shape having a concave portion by stretch molding or the like, and is used as an exterior container body. Further, the battery exterior packaging laminate is molded to obtain an exterior packaging lid portion in the same manner as the exterior packaging container body. After the battery body is housed in the concave portion of the outer package container body, the outer package lid portion is overlapped so as to cover the housed battery body, and the edge portion between the container body and the outer package lid portion is bonded to obtain a battery in which the battery body is housed in the outer package.

As described above, the adhesion of the peripheral edge portion between the outer packaging container main body and the outer packaging lid portion is widely performed by simple hot melt bonding (heat sealing). Therefore, a heat-sealable sealant layer is usually provided on the outermost layer (innermost layer) of the battery exterior laminate.

For example, patent document 1 discloses a battery packaging material comprising a laminate composed of at least a base material layer, an adhesive layer 1, a separator layer, an adhesive layer 2, and a sealant layer, wherein a specific adhesive resin composition is used. In patent document 1, a homopolypropylene layer is used as an outermost layer of a sealant layer (an innermost layer of the entire packaging material), and a battery packaging material that can be thermally connected at a normal heat-sealing temperature is obtained.

Documents of the prior art

Patent document

Patent document 1: japanese patent laid-open publication No. 2015-109287

Disclosure of Invention

Technical problem to be solved by the invention

In recent years, in expanding the application fields of batteries such as secondary batteries, excellent characteristics such as heat resistance and cold resistance are also required for battery outer packaging bodies. In addition, along with the recent expansion of demand for batteries, an increase in the production amount of batteries is required, and a battery exterior body capable of improving the production efficiency and yield in the production of batteries is required.

However, as described in patent document 1, in the laminate for a battery exterior packaging body having a sealant layer composed of a homopolypropylene layer as an outermost layer, the heat resistance and the cold resistance are insufficient, and there is room for improvement in the production efficiency and the yield in the production of a battery using the laminate for a battery exterior packaging body.

The present invention has been made in view of the above-described circumstances, and an object thereof is to provide a laminate for battery exterior packaging having excellent various characteristics, which can improve the work efficiency and yield in the production of a battery exterior packaging body using the laminate for battery exterior packaging.

Means for solving the problems

The present inventors have made extensive studies to achieve the above object, and as a result, they have found that: by using block polypropylene, random polypropylene and olefin elastomer having melting points that sufficiently satisfy a specific relationship at a specific ratio, the heat resistance and cold resistance of the laminate for battery exterior packaging itself can be improved; and a method for producing a battery exterior package using the laminate for battery exterior packaging, wherein the thermal fusion bonding can be performed at a relatively low temperature.

That is, the present invention adopts the following configuration.

A laminate for battery exterior packaging according to a first aspect of the present invention is a laminate for battery exterior packaging having at least a sealant layer, a first adhesive layer, a separator layer made of a metal foil, and a base material layer in this order, wherein the sealant layer is made of a block polypropylene, an random polypropylene, and an olefin elastomer, the content ratios of the block polypropylene, the random polypropylene, and the olefin elastomer in terms of mass ratio are A, B, C in this order, and the sealant layer satisfies the relationships of the following expressions (1) to (4) when the melting points of the block polypropylene, the random polypropylene, and the olefin elastomer are mpA, mpB, and mpC in this order:

A＞B (1)

A＞C (2)

A+B+C＝100 (3)

mpA＞mpB≧mpC (4)。

in the sealant layer, the content of the block polypropylene is preferably 35 to 80 mass%, the content of the random polypropylene is preferably 10 to 45 mass%, and the content of the olefin elastomer is preferably 10 to 40 mass%.

Preferably, a second sealant layer is further provided between the sealant layer and the first adhesive layer.

The first adhesive layer preferably contains maleic acid-modified polypropylene and a compound having an epoxy group or an oxazoline group.

The compound having an epoxy group is preferably a Phenol novolak type (phenonol novolak) epoxy resin or an epoxy group-containing polyolefin resin.

The compound having an oxazoline group is preferably an oxazoline group-containing styrene resin.

A battery exterior package according to a second aspect of the present invention is the battery exterior package according to the first aspect, which has an internal space for housing the battery, and the side of the sealant layer of the battery exterior package laminate is the side of the internal space.

A third aspect of the present invention is a method for producing a battery exterior body, including: a molding process comprising: pressing the first member made of the laminate for battery exterior packaging of the first aspect from the sealant layer side of the laminate for battery exterior packaging, thereby forming a container body having a concave portion; an assembly process comprising: combining the sealant layer of the container body and the sealant layer of the second member using the laminate for battery exterior packaging as a constituent material so as to overlap each other; a bonding process comprising: heat-fusing the overlapped sealant layers to join one sealant layer to the other, the heat-fusing having a temperature lower than the mpA and higher than the mpB.

A fourth aspect of the present invention is a method for producing a battery exterior body, including: a molding process comprising: a molding step of pressing a part of the member made of the laminate for battery exterior packaging of the first aspect from the sealant layer side of the laminate for battery exterior packaging to form a concave portion; an assembly process comprising: folding the member toward the sealant layer side in a region where the concave portion is not formed, and overlapping the sealant layer in a periphery of the concave portion in a first region on the concave portion side with respect to the formed folding line and the sealant layer in a second region on an opposite side of the concave portion with respect to the folding line; and a bonding step including: hot melt joining the superposed sealant layers to join one sealant layer to the other.

A battery according to a fifth aspect of the present invention is characterized by having the battery exterior body according to the second aspect.

Effects of the invention

According to the present invention, it is possible to provide a laminate for battery exterior packaging having excellent various characteristics such as heat resistance and cold resistance, which can improve the production efficiency and yield in the production of a battery exterior packaging body or a battery using the laminate for battery exterior packaging.

Drawings

Fig. 1 is a schematic cross-sectional view showing a first embodiment of a battery exterior laminate according to the present invention.

Fig. 2 is a perspective view showing an example of a secondary battery manufactured using the laminate for exterior packaging of a battery of the present invention.

Fig. 3 is a perspective view showing a process for producing a secondary battery using the laminate for external packaging of a battery of the present invention.

Fig. 4 is a perspective view showing a process of producing a secondary battery using the laminate for external packaging of a battery of the present invention.

Description of the reference numerals

11: sealant layer, 11': second sealant layer, 12: first adhesive layer, 13: first corrosion prevention layer, 14: isolation layer, 15: second corrosion prevention layer, 16: second adhesive layer, 17 base material layer, 20: battery exterior package, 27: lithium ion battery, 28: electrode lead, 29: peripheral edge portion, 30: container body, 31, 51: recess, 32: flange portion, 33: cover portion, 34: peripheral edge portion, 40, 60: secondary battery

Detailed Description

The present invention will be described below with reference to preferred embodiments.

[ laminate for packaging Battery ]

The battery exterior packaging laminate according to the first aspect of the present invention (hereinafter, may be simply referred to as "laminate") is a battery exterior packaging laminate having at least a sealant layer, a first adhesive layer, a separator layer made of a metal foil, and a base material layer in this order.

Fig. 1 is a schematic cross-sectional view showing the structure of a battery exterior laminate 10 according to an embodiment of the present invention.

The laminate 10 of the present embodiment includes a sealant layer 11, a second sealant layer 11', a first adhesive layer 12, a first corrosion prevention layer 13, a separator layer (metal foil) 14, a second corrosion prevention layer 15, a second adhesive layer 16, and a base material layer 17 in this order.

That is, the laminate 10 of the present embodiment is configured by an eight-layer structure having the first corrosion prevention layer 13 and the second corrosion prevention layer 15 formed on both surfaces of the separator layer 14, the sealant layer 11 and the second sealant layer 11' laminated on the first corrosion prevention layer 13 via the first adhesive layer 12, and the base material layer 17 laminated on the second corrosion prevention layer 15 via the second adhesive layer 16.

Each layer is described in detail below.

< sealant layer 11 >

The sealant layer 11 is a layer formed of block polypropylene, random polypropylene, and olefin elastomer.

In the present invention, "block polypropylene" (hereinafter, sometimes referred to as "block PP") means: mixtures consisting of polypropylene (homopolymer), ethylene-propylene copolymers (Impact Copolymer). Such a mixture is obtained by preparing polypropylene (propylene homopolymer) using a raw material monomer and then polymerizing ethylene and propylene in the presence of the homopolymer, and is usually a mixture in which an ethylene-propylene rubber is dispersed in polypropylene.

Further, "random polypropylene" (hereinafter sometimes referred to as "random PP") means: random copolymers of propylene-ethylene.

The polypropylene/ethylene-propylene copolymer ratio, the propylene/ethylene ratio, the polymerization degree, and the like in the block polypropylene and the random polypropylene are not particularly limited, and may be appropriately determined so as to satisfy the block PP and the random polypropylene of the following formulae (1) to (4).

In the present invention, the olefin-based elastomer is not particularly limited as long as it is an olefin-based polymer having properties as an elastomer.

Examples of the olefin polymer include homopolymers such as polyethylene, polypropylene, poly-1-butene and polyisobutylene; copolymers such as propylene-ethylene copolymers, ethylene-1-butene copolymers, ethylene-1-hexene copolymers, ethylene-1-octene copolymers, propylene-ethylene-1-butene copolymers, propylene-1-butene copolymers, styrene-butadiene copolymers, and styrene-ethylene copolymers.

In the present invention, the block PP, the random PP, and the olefin elastomer constituting the sealant layer 11 satisfy the relationships of the following expressions (1) to (4).

A＞B (1)

A＞C (2)

A+B+C＝100 (3)

mpA＞mpB≧mpC (4)

A is the content (mass ratio) of the block polypropylene, B is the content (mass ratio) of the random polypropylene, and C is the content (mass ratio) of the olefin elastomer. mpA is the melting point of the block polypropylene, mpB is the melting point of the random polypropylene, and mpC is the melting point of the olefinic elastomer.

As shown in the above formula (3), the resin component of the sealant layer 11 is composed of only three components of block PP, random PP, and olefin elastomer. The number of types of polymers constituting the sealant layer 11 is not limited as long as the polymers are classified into any one of the three components, and may be three or more. For example, as the olefin-based elastomer, two or more kinds of olefin-based elastomers having different compositions or physical properties may be used in combination.

As shown in formula (4), among the block PP, random PP, and olefin elastomer constituting the sealant layer 11, the block PP has the highest melting point. And the random PP has the same melting point as the olefinic elastomer, or a higher melting point than the olefinic elastomer.

By including polymers having at least two or more different melting points in the sealant layer 11 as described above, and by appropriately setting the temperature applied at the time of hot-melt bonding of the sealant layer 11, it is possible to melt a part of the polymers in the sealant layer 11 at the time of hot-melt bonding and to bring a part of the polymers into an unmelted state.

Further, as shown in the above formulas (1) and (2), among the three components constituting the sealant layer 11, the sealant layer 11 contains the block PP at most. Since the block PP, which is the highest melting point component among the three components, is contained at the maximum, the main component of the sealant layer 11 is not melted even at a higher temperature. By using the unmelted block PP as the support and performing the hot-melt joining using the other two molten components, the hot-melt joining can be performed while maintaining the mechanical strength of the sealant layer 11, and the mechanical strength of the battery exterior body finally obtained can also be improved.

Further, by containing a large amount of block PP in the sealant layer 11, the heat resistance of the sealant layer 11 and the battery exterior laminate 10 can be improved.

As mentioned above, the sealant layer 11 contains the most block PP. On the other hand, the relative content ratio (mass ratio) between the random PP and the olefin-based elastomer is not particularly limited. B > C, C > B, and B ═ C may be used, but B ≧ C is preferred, and B > C is more preferred.

The content ratio of the block PP (A in the formulae (1) to (3)) is preferably 35 to 80% by mass, more preferably 35 to 60% by mass, still more preferably 35 to 50% by mass, and particularly preferably 35 to 45% by mass.

The content ratio of the random PP (B in the formulae (1) to (3)) is preferably 10 to 45% by mass, more preferably 20 to 45% by mass, still more preferably 25 to 40% by mass, and particularly preferably 30 to 40% by mass.

The content ratio of the olefin-based elastomer (C in the formulae (1) to (3)) is preferably 10 to 40% by mass, more preferably 20 to 35% by mass, and particularly preferably 20 to 30% by mass.

The melting point (mpA) of the block PP is preferably 160 ℃ or higher. The melting point (mpB) of the random PP is preferably 120 ℃ or higher and less than 160 ℃. The melting point (mpC) of the olefinic elastomer is preferably 40 ℃ or more and less than 160 ℃, more preferably 120 ℃ or more and less than 160 ℃.

The thickness of the sealant layer 11 may be, for example, 1 to 200 μm, preferably 5 to 100 μm, and more preferably 5 to 40 μm.

In the present invention, the sealant layer contains all three of block PP, random PP, and olefin elastomer. Conventionally, the sealant layer of a large number of battery outer packaging laminates has been produced by using only one of these resins. However, in the sealant layer composed of only one of these resins, there are disadvantages in addition to advantages due to the characteristics of each resin, and further improvement of the characteristics is required.

For example, when a sealant layer made of only block PP is used, block PP has high heat resistance, and therefore, the advantage of improving the heat resistance of the sealant layer and the entire battery exterior laminate is obtained. Further, the use of the block PP having a high resin strength also has an advantage that a laminate for battery exterior packaging having excellent mechanical strength can be obtained. On the other hand, when the sealant layer made of the block PP is used, since it is necessary to set the heat sealing (hot melt bonding) amount in the case of manufacturing the battery exterior body using the battery exterior laminate, there is a possibility that defects in the heat sealing are likely to occur and the yield is lowered in addition to the low production efficiency.

In addition, when a sealant layer composed of only random PP is used, the production efficiency and yield at the time of heat sealing are sufficient, but there is a possibility that the heat resistance of the sealant layer and the battery exterior laminate itself is lowered.

Further, when a sealant layer composed only of an olefin elastomer is used, since the olefin elastomer is generally low in melting point, heat sealing can be performed at low temperature, and the production efficiency and yield at the time of heat sealing become extremely high. On the other hand, the olefin-based elastomer has a low melting point, and therefore, the heat resistance of the entire sealant layer and the battery exterior laminate may be reduced.

As described above, when used in a laminate for battery exterior packaging, the sealant layers using the respective resins alone have properties that need to be improved. In contrast, in the battery exterior laminate of the present invention, by using not only three resins having a specific relationship between melting points but also the three resins at specific ratios, the advantages of the respective resins as described above can be produced and the disadvantages can be complemented with each other. The laminate for battery exterior packaging of the present invention using such a sealant layer can improve heat resistance and cold resistance, and can be heat-sealed at a relatively low temperature when the battery exterior packaging is produced, so that the production efficiency and yield in the production of the battery exterior packaging can be improved.

< second sealant layer 11' >

The battery exterior laminate 10 of the present embodiment has a second sealant layer 11'. In the present invention, the second sealant layer 11' has an arbitrary structure.

The second sealant layer 11' is provided on the outer layer side (separator side) of the sealant layer 11 as the innermost layer, and has a function of fusing the sealant layers together with the sealant layer 11 at the time of thermal fusion bonding. By providing the second sealant layer 11' in addition to the sealant layer 11, the heat seal strength at the time of the hot melt joining can be further improved.

The second sealant layer 11' is not particularly limited as long as it has a composition different from that of the sealant layer 11, but is preferably a layer made of polyolefin. Examples of the layer made of polyolefin include polyethylene, polypropylene, poly-1-butene, polyisobutylene, a random copolymer of propylene and ethylene or α -olefin, block polypropylene, and an olefin elastomer.

Among them, the second sealant layer 11' is preferably a layer composed of at least one selected from the group consisting of homopolypropylene (propylene homopolymer), a propylene-ethylene random copolymer (random PP), block propylene, and an olefin elastomer, from the viewpoint of improving adhesiveness to the sealant layer 11 and the first adhesive layer 12. Among these, a layer composed of a block polypropylene and/or an olefin-based elastomer is more preferable, and a layer composed of a block polypropylene and an olefin-based elastomer is particularly preferable.

The second sealant layer 11' may have a single-layer structure or a multi-layer structure.

The melting point of the material used for the second sealant layer 11' is not particularly limited as long as it has heat resistance necessary for the battery exterior laminate 10.

The thickness of the second sealant layer 11' may be, for example, 1 to 200 μm, preferably 5 to 100 μm, and more preferably 5 to 40 μm.

When the second sealant layer 11 'is provided, the total thickness of the sealant layer 11 and the second sealant layer 11' may be, for example, 0.5 to 50 μm, preferably 2 to 30 μm, and more preferably 5 to 20 μm.

< first adhesive layer 12 >

The first adhesive layer 12 is provided for bonding the sealant layer 11 provided with the second sealant layer 11' as needed, and the separator layer 14 having the first corrosion prevention layer 13 formed on the surface thereof.

The material of the adhesive forming the first adhesive layer 12 is not particularly limited as long as the above-described layer can be satisfactorily adhered, but for example, a layer composed of an adhesive containing the acid-modified polyolefin resin (a) and the crosslinkable compound (B) is preferable from the viewpoint of satisfying adhesiveness and storage modulus.

Hereinafter, the acid-modified polyolefin resin (a) may be referred to as "component (a)" and the crosslinkable compound (B) may be referred to as "component (B)".

(acid-modified polyolefin resin (A))

In the present invention, the acid-modified polyolefin resin (a) ((a) component) means: the polyolefin-based resin modified with an unsaturated carboxylic acid or a derivative thereof has an acidic functional group such as a carboxyl group or a carboxylic acid anhydride group.

(A) The component (B) is obtained by modifying a polyolefin resin with an unsaturated carboxylic acid or a derivative thereof, or by copolymerizing an acidic functional group-containing monomer with an olefin. Among them, the polyolefin-based resin is preferably acid-modified as the component (A).

As an acid modification method, graft modification of a polyolefin resin and an acidic functional group-containing monomer by melt-kneading in the presence of a radical polymerization initiator such as an organic peroxide or an aliphatic azo compound is exemplified.

Examples of the polyolefin resin include polyethylene, polypropylene, poly-1-butene, polyisobutylene, a copolymer of propylene and ethylene, and a copolymer of propylene and an olefin monomer.

Examples of the olefin monomer to be copolymerized include 1-butene, isobutene, and 1-hexene.

The copolymer may be a block copolymer, and may also be a random copolymer.

Among them, as the polyolefin-based resin, polypropylene-based resins polymerized from propylene such as homopolypropylene (propylene homopolymer), a copolymer of propylene and ethylene, and a copolymer of propylene and butene as a raw material are preferable; particularly preferred is a propylene-1-butene copolymer, i.e., a polyolefin resin having a methyl group and an ethyl group in a side chain. By containing 1-butene, the molecular movement of the resin when heated can be promoted, and the chance of contact between the crosslinking points of the component (a) and the crosslinking points of the component (B) described later can be increased, and as a result, the adhesiveness to an adherend can be further improved.

The acid functional group-containing monomer is a compound having an ethylenic double bond, a carboxyl group or a carboxylic anhydride group in the same molecule, and examples thereof include various unsaturated monocarboxylic acids, dicarboxylic acids or anhydrides of dicarboxylic acids.

Examples of the acid functional group-containing monomer having a carboxyl group (carboxyl group-containing monomer) include α, β -unsaturated carboxylic acid monomers such as acrylic acid, methacrylic acid, maleic acid, nadic acid, fumaric acid, itaconic acid, citraconic acid, crotonic acid, isocrotonic acid, tetrahydrophthalic acid, and endo-bicyclo [2.2.1] -5-heptene-2, 3-dicarboxylic acid (norbornene diacid)).

Examples of the acid functional group-containing monomer having a carboxylic anhydride group (carboxylic anhydride group-containing monomer) include unsaturated dicarboxylic anhydride monomers such as maleic anhydride, nadic anhydride, itaconic anhydride, citraconic anhydride, and nadic anhydride.

In the component (A), these acid functional group-containing monomers may be used singly or in combination of two or more.

Among them, as the acidic functional group-containing monomer, a monomer containing an acidic functional group which favorably reacts with a crosslinkable functional group in the component (B) described later is preferable; more preferred are acid functional group-containing monomers having an acid anhydride group, from the viewpoint of high reactivity with a crosslinkable functional group; further preferred are carboxylic anhydride group-containing monomers; maleic anhydride is particularly preferred.

In order to prevent a decrease in adhesive strength due to the unreacted acidic functional group-containing monomer when a part of the acidic functional group-containing monomer used for the acid modification is unreacted, it is preferable to use a monomer obtained by previously removing the unreacted acidic functional group-containing monomer as the component (a).

In the component (a), the component derived from the polyolefin resin or the olefin is preferably 50 parts by mass or more with respect to 100 parts by mass of the total amount of the component (a).

The melting point of the component (A) is not particularly limited.

When the first adhesive layer 12 is a dry lamination adhesive layer, the melting point of the component (a) is preferably 50 to 100 ℃, more preferably 60 to 98 ℃, even more preferably 70 to 98 ℃, and even more preferably 75 to 95 ℃.

When the melting point of the component (a) is not less than the lower limit, the heat resistance of the first adhesive layer 12 can be improved, and as a result, the heat resistance and durability after the sealant layer 11 and the separator layer 14 having the first corrosion prevention layer 13 are bonded via the first adhesive layer 12 can be improved.

On the other hand, when the melting point of the component (a) is not more than the above upper limit, and the component (a) is dissolved in an organic solvent to obtain a solvent-type adhesive for dry lamination, the component (a) is easily dissolved in the organic solvent, so that a more uniform adhesive can be obtained, the component (a) and the component (B) are favorably reacted, and the adhesiveness and the durability are improved. By using the component (a) having a melting point of not more than the above upper limit, the temperature at the time of dry lamination via the first adhesive layer 12 or the curing temperature after lamination can be made relatively low. As a result, wrinkles due to heat are less likely to occur in the sealant layer 11 bonded using the first adhesive layer 12, and the heat resistance requirement of the sealant layer 11 is relaxed as well as the yield in production is improved, so that the range of selection of the material for the sealant layer 11 can be expanded. Further, as a result of being able to perform the lamination process at a relatively low temperature, the time for the lamination process can be shortened, and the energy required for the lamination process can also be reduced, so that the production efficiency can be improved and the energy consumption can be reduced.

On the other hand, the adhesive used for forming the first adhesive layer 12 does not contain an organic solvent, and when the component (a) and the component (B) described later are melt-kneaded to form the adhesive, the melting point of the component (a) is preferably 100 to 180 ℃. The first adhesive layer 12 made of such an adhesive is suitably used as an adhesive layer for thermal lamination.

By using the component (a) having a melting point within the above range, the component (a) and the component (B) described later can be melt-kneaded at a temperature sufficiently higher than the melting point of the component (a) even when a conventional method and a conventional apparatus are used. When the component (a) is reacted with the component (B) described later by melt kneading, the melting point of the component (B) is preferably lower than that of the component (a), and the degree of freedom in selecting the component (B) can be increased by using the component (a) having the melting point in the above range.

As described above, the melting point of component (a) is preferably higher than the melting point of component (B) described later, more preferably the melting point of component (a) is higher than the melting point of component (B) by 10 ℃ or more, still more preferably 20 ℃ or more, and particularly preferably 30 ℃ or more. When the melting point of the component (a) is sufficiently higher than that of the component (B), the component (B) is melted first and impregnated into the component (a) in a state of maintaining the resin shape during melt kneading, and the component (a) and the component (B) are allowed to react uniformly, whereby good durability can be obtained.

(A) The molecular weight of the component (B) is not particularly limited, and is not particularly limited as long as the desired melting point can be sufficiently obtained, but a resin having a molecular weight of 10000 to 800000 is usually used, preferably a resin having a molecular weight of 50000 to 650000 is used, more preferably a resin having a molecular weight of 80000 to 550000 is used, and further preferably a resin having a molecular weight of 100000 to 450000 is used.

Among them, maleic anhydride-modified polypropylene is preferable as the component (A) from the viewpoint of adhesiveness, durability, and the like.

(crosslinkable Compound (B))

(B) The component (b) is not particularly limited as long as it is a compound capable of imparting crosslinkability to the first adhesive layer, and a compound having a crosslinkable functional group is preferable. As the compound having a crosslinkable functional group, a compound having an epoxy group or an oxazoline group is preferable, and specifically, as a preferable compound, an epoxy group-containing polyolefin resin (b 1); a compound (b2) containing a plurality of epoxy groups, which does not correspond to the compound (b 1); an oxazoline group-containing styrene-based resin (b 3). The details are described below.

Epoxy-containing polyolefin-based resin (b1)

In the present invention, the epoxy group-containing polyolefin resin (b1) (hereinafter sometimes referred to as "component (b 1)") has a main chain obtained by copolymerizing monomers including an olefin compound and an epoxy group-containing vinyl monomer, and a side chain bonded to the main chain, and has a melting point of 80 to 120 ℃.

Main chain

(b1) The main chain of component (b) is obtained by copolymerizing an olefin compound, an epoxy group-containing vinyl monomer, and optionally other monomers used as needed.

Examples of the olefin compound include olefin monomers such as ethylene, propylene, 1-butene, isobutylene, 1-hexene, and α -olefin.

Examples of the epoxy group-containing vinyl monomer include glycidyl esters such as Glycidyl Methacrylate (GMA) and glycidyl acrylate, glycidyl ethers such as allyl glycidyl ether, epoxy olefins such as epoxybutene, and the like.

The olefin compound and the epoxy group-containing vinyl monomer may be used singly or in combination of two or more.

(b1) The main chain of the component (A) may contain one or more other monomers in addition to the olefin compound and the epoxy group-containing vinyl monomer. The other monomer is not particularly limited as long as it is copolymerizable with the olefin compound and the epoxy group-containing vinyl monomer, and examples thereof include a (meth) acrylate monomer, a (meth) acrylate ester monomer, a (meth) acrylamide monomer, and a styrene monomer.

In the copolymer to be the main chain of the component (b1), the proportion of each monomer (compound) is not particularly limited, but a copolymer obtained by copolymerizing 10 to 30 mass%, more preferably 10 to 20 mass% of an epoxy group-containing vinyl monomer with respect to the total monomers constituting the main chain of the component (b1) is preferable. By using the epoxy group-containing vinyl monomer in the above range, the adhesiveness to the adherend can be suitably improved.

Among them, as the main chain of the component (b1), a copolymer obtained by copolymerizing an olefin compound and an epoxy group-containing vinyl monomer is preferable, and a copolymer of ethylene and glycidyl methacrylate is particularly preferable.

Side chain

(b1) The component (C) has a side chain bonded to the main chain, whereby the properties of the olefin copolymer, such as strength, adhesiveness and synthesis, can be improved. The side chain is not particularly limited, and examples thereof include styrene resins (styrene-containing polymers) such as polystyrene and styrene-acrylonitrile copolymers; and (meth) acrylic resins obtained by polymerizing at least one of alkyl (meth) acrylate monomers such as methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, and pentyl (meth) acrylate.

Among them, the side chain of the component (b1) is preferably a styrene-containing polymer, and examples thereof include polystyrene and a styrene-acrylonitrile copolymer. Among them, polystyrene is particularly preferable.

(b1) When the component (B) is a polymer containing polystyrene as a side chain, the fluidity in a molten state is improved. Therefore, it is considered that the epoxy group has appropriate fluidity at the time of heat bonding, and the epoxy group is likely to come into contact with an adherend, thereby improving the bonding strength and durability.

The component (b1) having the main chain and the side chain as described above can be obtained by graft polymerization using, for example, a main chain copolymer obtained by a conventional method, a monomer constituting the side chain, and a radical polymerization initiator such as an organic peroxide or an aliphatic azo compound.

(b1) The melting point of the components is 80-120 ℃, and preferably 90-110 ℃. The component (b1) having such a melting point can be obtained by appropriately selecting the types of monomers constituting the main chain and the side chain.

By using the component (b1) having a melting point within the above range, even when a conventional method or a conventional apparatus is used, the component (a) and the component (b1) can be melt-kneaded at a temperature sufficiently higher than the melting point of the component (b1), and an adhesive or an adhesive layer having excellent durability can be obtained. When the component (a) and the component (b1) are reacted by melt kneading, the melting point of the component (b1) is preferably lower than that of the component (a), and the degree of freedom in selecting the component (a) can be increased by using the component (b1) having the above melting point range.

As the component (b1), commercially available products such as MODIPER A1100, A4100 and A4400 (both trade names) manufactured by Nikkiso K.K. can be used.

Compound having plural epoxy groups (b2)

The compound (b2) containing a plurality of epoxy groups (hereinafter sometimes referred to as "(b 2) component") is a compound that does not correspond to the (b 1). (b2) The component (C) may be a low molecular compound or a high molecular compound. The component (b2) is preferably a polymer compound (resin) in view of good miscibility and compatibility with the component (a). On the other hand, when the adhesive is a solvent-based adhesive for dry lamination, the component (b2) is preferably a low molecular compound from the viewpoint of good solubility in an organic solvent.

(b2) The structure of component (a) is not particularly limited as long as it has a plurality of epoxy groups, and examples thereof include phenoxy resins synthesized from bisphenols and epichlorohydrin; a novolac type epoxy resin; bisphenol type epoxy resins, and the like. Among them, a novolac type epoxy resin is preferably used because it has a high epoxy content per molecule and can form a dense crosslinked structure particularly together with the component (a).

In the present invention, the phenolic epoxy resin means: a compound having a basic structure of a phenol resin obtained by acid condensation of phenol and formaldehyde and having an epoxy group introduced into a part of the structure. The amount of epoxy groups introduced per molecule in the novolac epoxy resin is not particularly limited, but is generally a polyfunctional epoxy resin because many epoxy groups are introduced into phenolic hydroxyl groups present in a large amount in the novolac resin by reacting an epoxy-based raw material such as epichlorohydrin with the novolac resin.

Among them, as the novolac type epoxy resin, a bisphenol a novolac type epoxy resin having a novolac structure as a basic skeleton and a bisphenol a structure is preferable. The bisphenol a structure in the epoxy resin may be a structure derived from bisphenol a, and the hydroxyl groups at both ends of bisphenol a may be replaced with groups such as epoxy-containing groups.

As an example of the bisphenol a novolac type epoxy resin, a resin represented by the following general formula (1) can be cited.

[ chemical formula 1]

In the general formula (1), R¹～R⁶Each independently represents a hydrogen atom or a methyl group, n is an integer of 0 to 10, R^XIs a group having an epoxy group.

In the general formula (1), R¹～R⁶Each independently is a hydrogen atom or a methyl group. When n is an integer of 2 or more, R³，R⁴May be the same or different.

In the resin represented by the general formula (1), at least one of the following conditions (i) to (iii) is preferably satisfied.

(i)R¹And R²Both of which are methyl groups, (ii) R³And R⁴Both of these are methyl, (iii) R⁵And R⁶Both of which are methyl groups

For example, by satisfying the above (i), in the general formula (1), R is bonded¹And R²And two hydroxyphenyl groups bonded to the carbon atom of (a) constitute a structure derived from bisphenol A.

In the formula (1), R^XIs a group having an epoxy group. Examples of the group having an epoxy group include an epoxy group and a combination of an epoxy group and an alkylene group, and among them, a glycidyl group is preferable.

The epoxy equivalent of the bisphenol A novolac epoxy resin is preferably 100 to 300, and more preferably 200 to 300. The epoxy equivalent (g/eq) is the molecular weight of the epoxy resin per epoxy group, and a smaller value means a larger number of epoxy groups in the resin. By using an epoxy resin having a small epoxy equivalent, the adhesion of the epoxy resin to an adherend is good and the epoxy resin and the acid-modified polyolefin resin are sufficiently crosslinked even when the amount of the added epoxy resin is small.

As such a novolac-type epoxy resin, jER154, jER157S70, jER-157S 65; commercially available products such as EPICLON N-730A, EPICLON N-740, EPICLON-770 and EPICLON-775 (trade names thereof) manufactured by DIC corporation.

By using the epoxy resin as described above, both the acidic functional group of the component (a) and the epoxy group of the component (b2) function as adhesive functional groups to an adherend (particularly, functional groups such as carboxyl groups of the first corrosion-resistant layer 13), and therefore it is considered that excellent adhesion can be achieved to the separator layer 14 having the first corrosion-resistant layer 13 on the surface thereof with respect to the sealant layer 11.

Further, it is found that a part of the acidic functional group of the component (a) and a part of the epoxy group of the component (b2) react with each other to form a crosslinked structure of the component (a) and the component (b2) in the first adhesive layer 12, and as a result, the strength of the first adhesive layer 12 is enhanced by the crosslinked structure, and excellent adhesiveness and good durability are obtained.

Oxazoline group-containing styrene-based resin (b3)

By using, as the component (B), an oxazoline group-containing styrene-based resin (B3) (hereinafter, sometimes referred to as a "(B3) component") which reacts with an acidic functional group (for example, a carboxyl group, a carboxylic acid group, or the like) of the component (a) to form a crosslinked structure. For example, when the acidic functional group of the component (A) is a carboxyl group, the following crosslinking reaction occurs to form an amide ester bond. As a result, it was found that the strength of the resin was increased by the crosslinked structure, and excellent adhesion and durability were obtained.

[ chemical formula 2]

Among them, the component (b3) is preferably a resin obtained by copolymerizing a styrene monomer and an oxazoline group-containing monomer.

As the styrene-based monomer, styrene and its derivatives can be used. Specific examples thereof include alkylstyrenes such as styrene, α -methylstyrene, dimethylstyrene, trimethylstyrene, ethylstyrene, diethylstyrene, triethylstyrene, propylstyrene, butylstyrene, hexylstyrene, heptylstyrene, and octylstyrene; halogenated styrenes such as chlorobenzene, fluorostyrene, bromostyrene, dibromostyrene, iodostyrene, and the like. Among them, styrene is preferable.

The oxazoline group-containing monomer is not particularly limited in its skeleton as long as it is an oxazoline group-containing monomer copolymerizable with the styrene-based monomer, and a monomer having an oxazoline group and a vinyl group can be suitably used.

Examples of oxazoline group-containing vinyl monomers include 2-vinyl-2-oxazoline, 5-methyl-2-vinyl-2-oxazoline, 4-dimethyl-2-vinyl-2-oxazoline, 2-isopropenyl-2-oxazoline, 4-dimethyl-2-isopropenyl-2-oxazoline, 4-acryloyl-hydroxymethyl-2, 4-dimethyl-2-oxazoline, 4-methacryloyl-hydroxymethyl-2-phenyl-4-methyl-2-oxazoline, and mixtures thereof, 2- (4-vinylphenyl) -4, 4-dimethyl-2-oxazoline, 4-ethyl-4-hydroxymethyl-2-isopropenyl-2-oxazoline, 4-ethyl-4-ethoxycarbonylmethyl-2-isopropenyl-2-oxazoline, and the like. Among them, 2-isopropenyl-2-oxazoline is preferable.

The styrene monomer and the oxazoline group-containing monomer may be used singly or in combination of two or more.

The component (b3) may contain one or more other monomers in addition to the styrene-based monomer and the oxazoline group-containing monomer. The other monomer is not particularly limited as long as it is copolymerizable with these monomers, and examples thereof include (meth) acrylate monomers, (meth) acrylamide monomers, and the like.

In the component (b3), the proportion of each monomer is not particularly limited, but a resin obtained by copolymerizing 5 to 50 mass%, more preferably 10 to 30 mass% of an oxazoline group-containing monomer with respect to the total monomers constituting the component (b3) is preferable. By using the oxazoline group-containing monomer in the above range, the component (a) and the component (b3) can be sufficiently crosslinked, and good durability can be obtained.

(b3) The number average molecular weight of the component (A) is preferably 3 to 25 ten thousand, more preferably 5 to 20 ten thousand, still more preferably 6 to 10 ten thousand, and most preferably 6 to 8 ten thousand. By using the component (b3) having a number average molecular weight within the above range, the compatibility between the component (A) and the component (b3) can be improved, and the component (A) and the component (b3) can be sufficiently crosslinked.

As such a component (b3), a commercially available product such as EPOCROSRPS-1005 (trade name) manufactured by Japan catalyst company can be used.

By using the component (B) as described above, both the acidic functional group of the component (a) and the crosslinkable functional group of the component (B) function as adhesive functional groups to an adherend (particularly, functional groups such as carboxyl groups of the first corrosion prevention layer 13), and thus excellent adhesion can be achieved to the sealant layer 11 or the first sealant layer 11' and the separator layer 14 having the first corrosion prevention layer 13 on the surface.

Further, a part of the acidic functional group of the component (a) reacts with a part of the crosslinkable functional group of the component (B) to form a crosslinked structure of the component (a) and the component (B) in the first adhesive layer 12, and as a result, the strength of the first adhesive layer 12 is increased by the crosslinked structure, and excellent adhesiveness and good durability are obtained.

The first adhesive layer 12 preferably contains 1 to 20 parts by mass of the component (B) per 100 parts by mass of the component (A); the component (B) is preferably contained in an amount of 5 to 10 parts by mass based on 100 parts by mass of the component (A); the component (B) is preferably contained in an amount of 5 to 7 parts by mass based on 100 parts by mass of the component (A).

(optional Components)

The adhesive used in the present invention may or may not further contain an organic solvent.

The solvent-based adhesive for dry lamination can be formed by forming a liquid adhesive by containing an organic solvent. The first adhesive layer 12 can be formed by applying such a liquid adhesive to a layer as a lower layer (for example, the surface of the separator layer 14 on which the first corrosion-resistant layer 13 is provided) and drying the applied liquid adhesive. By selective coating instead of extrusion molding, the adhesive layer can be formed in a thinner layer, and the adhesive layer can be made thinner and the laminate using the adhesive layer can be made thinner as a whole.

On the other hand, when the organic solvent is not contained, an adhesive layer suitable for thermal lamination or the like can be formed by melt-kneading the component (a) and the component (B) and then performing extrusion molding or the like.

When the organic solvent is contained, the organic solvent used is not particularly limited as long as the above-mentioned component (a), component (B), and other optional components used as necessary (described in detail later) can be appropriately dissolved to form a uniform solution, and any of known solvents can be used as the solvent of the solution type adhesive. The liquid adhesive is usually used by applying it to an adherend (for example, the surface of the separator 14 on which the first anticorrosive layer 13 is provided) and then evaporating the organic solvent by heating or the like. Therefore, from the viewpoint of easy volatilization, an organic solvent having a boiling point of 150 ℃ or lower is preferable.

Specific examples of the organic solvent include aromatic solvents such as toluene, xylene, anisole, ethylbenzyl ether, cresyl methyl ether, diphenyl ether, dibenzyl ether, phenetole, butylphenyl ether, ethylbenzene, diethylbenzene, pentylbenzene, isopropylbenzene, cymene, mesitylene, etc.; aliphatic solvents such as n-hexane; ketone solvents such as methyl ethyl ketone, acetone, cyclohexanone, methyl n-pentanone, methyl iso-pentanone, and 2-heptanone; ester solvents such as methyl lactate, ethyl lactate, methyl acetate, ethyl acetate, butyl acetate, methyl pyruvate, ethyl pyruvate, methyl methoxypropionate, and ethyl ethoxypropionate; alcohol solvents such as methanol, ethanol, and isopropanol; polyhydric alcohol solvents such as ethylene glycol, diethylene glycol, propylene glycol, and dipropylene glycol.

The organic solvent may be used alone or in combination of two or more kinds, and may be used in the form of a mixed solvent. When a mixed solvent is used, it is preferable to use an organic solvent in which the component (a) is well dissolved and an organic solvent in which the component (B) is well dissolved in combination. The combination is preferably a combination of toluene in which the component (A) is favorably dissolved and methyl ethyl ketone in which the component (B) is favorably dissolved. When a mixed solvent is used, the components (A) and (B) may be dissolved after two or more organic solvents are mixed in advance; after the respective components of the component (a) and the component (B) are dissolved in respective good solvents, a plurality of organic solvents in which the respective components are dissolved may be mixed.

When a plurality of organic solvents are used in combination, the ratio of the respective organic solvents is not particularly limited, and when toluene and methyl ethyl ketone are used in combination, for example, the mixing ratio thereof is preferably toluene: methyl ethyl ketone is 60-95: 5-40 (mass ratio), and more preferably toluene: the methyl ethyl ketone accounts for 70-90: 10-30 (mass ratio).

The adhesive used in the present invention may further contain other components in addition to the above-mentioned component (a), component (B) and organic solvent. As other components, additives having mixing properties or resins having additive properties are exemplified, and more specifically, catalysts, crosslinking agents, plasticizers, stabilizers, colorants, and the like can be used.

The solid content of the adhesive used in the present invention preferably contains more than 50 parts by mass and 99.5 parts by mass or less of component (a) and 0.5 parts by mass or more and less than 50 parts by mass of component (B). That is, the binder used in the present invention contains the component (a) as a main component in excess of half of the mass ratio of the solid components of the binder. More preferably, the amount of the component (B) is 0.5 to 30 parts by mass relative to 70 to 99.5 parts by mass of the component (A); further preferably, the component (B) is 1 to 20 parts by mass relative to 80 to 99 parts by mass of the component (A); particularly, it is preferable that the amount of the component (B) is 2 to 10 parts by mass relative to 90 to 98 parts by mass of the component (A).

In addition, even when the adhesive used in the present invention contains solid components other than the components (a) and (B) as optional components, the component (a) is always the main component. Therefore, even when any component is contained, the amount of the component (a) exceeds 50 parts by mass in the entire solid content of the adhesive. For example, the adhesive contains 70 to 99.5 parts by mass of the component (A), 0.5 to 29.5 parts by mass of the component (B) and 0.5 to 29.5 parts by mass of other components in the total solid content.

When the adhesive used in the present invention contains an organic solvent, the amount of the organic solvent used is not particularly limited as long as the component (a), (B), or any other component can be dissolved well, and the solid content concentration is usually preferably 3 to 30% by mass, more preferably 5 to 25% by mass, and still more preferably 7 to 20% by mass.

The thickness of the first adhesive layer 12 may be, for example, 0.1 to 50 μm, preferably 0.5 to 10 μm, and more preferably 0.7 to 5 μm. By setting the thickness within this range, the sealant layer 11 provided with the second sealant layer 11' as needed and the separator layer 14 provided with the first corrosion prevention layer 13 can be bonded with high adhesion force, thereby preventing interlayer peeling.

< first anti-corrosion layer 13 >

In this embodiment, the first corrosion prevention layer 13 is a layer for preventing corrosion of the separator 14 due to rust or the like.

The first corrosion prevention layer 13 preferably contains a halogenated metal compound, and a halogenated metal compound described later may be directly plated on the surface of the barrier layer 14. By providing such a first corrosion prevention layer 13, a good rust prevention effect can be imparted to the metal foil.

The first corrosion prevention layer 13 preferably further contains a water-soluble resin, a chelating agent, or a crosslinkable compound in addition to the halogenated metal compound. Therefore, the first corrosion prevention layer 13 preferably contains a halogenated metal compound, a water-soluble resin, and a chelating agent or a crosslinkable compound; the first anti-corrosion layer 13 is preferably formed by applying an aqueous solution containing a halogenated compound, a water-soluble resin, a chelating agent, or a crosslinkable compound to the layer as the lower layer, and then drying and curing the applied aqueous solution. Hereinafter, the material forming the first corrosion prevention layer 13 may be referred to as "corrosion prevention treatment agent".

(halogenated Metal Compound)

The halogenated metal compound has an effect of improving chemical resistance such as electrolyte resistance. That is, the surface of the separator 14 can be passivated to improve the corrosion resistance to the electrolyte. When the first corrosion prevention layer 13 contains a water-soluble resin described later, the metal halide compound also has a function of crosslinking the water-soluble resin.

The metal halide compound is preferably water-soluble in view of miscibility with a water-soluble resin described later and dispersion in a water-soluble medium and coating.

Examples of the metal halide compound include a chromium halide, an iron halide, a zirconium halide, a titanium halide, a hafnium halide, a titanium hydrohalide, and salts thereof. Examples of the halogen atom include chlorine, bromine and fluorine, and chlorine or fluorine is preferable. Further, fluorine is particularly preferable. By containing fluorine in the halogenated metal compound, hydrofluoric acid (HF) can be generated from the corrosion preventing treatment agent depending on the conditions.

Further, the metal halide compound may have atoms other than halogen atoms and metals.

Among them, as the halogenated metal compound, a chloride or fluoride of iron, chromium, manganese or zirconium is preferable.

(Water-soluble resin)

As the water-soluble resin, at least one selected from the group consisting of a polyvinyl alcohol resin or a derivative thereof, and a polyvinyl ether resin is preferably used.

The polyvinyl alcohol resin or its derivative is preferably a polyvinyl alcohol resin or a modified polyvinyl alcohol resin.

The polyvinyl alcohol resin can be prepared, for example, by saponifying a polymer of a vinyl ester monomer or a copolymer thereof.

Examples of the polymer or copolymer of the vinyl ester monomer include homopolymers or copolymers of a fatty acid vinyl ester such as vinyl formate, vinyl acetate or vinyl butyrate, or a vinyl ester monomer such as an aromatic vinyl ester such as vinyl benzoate, and copolymers of the vinyl ester monomer and other monomers copolymerizable therewith.

The saponification degree of the polyvinyl alcohol resin or the modified polyvinyl alcohol resin is preferably 90 mol% or more, more preferably 90 to 99.9 mol%, and still more preferably 95 to 99 mol%.

By providing the (modified) polyvinyl alcohol resin with both a hydrophobic group derived from a side chain of polyvinyl ester (for example, in the case of vinyl acetate, the hydrophobic group is an acetyl group) and a hydrophilic hydroxyl group obtained by saponification, the reaction with the surface of the metal foil can be performed more favorably than with a resin having a degree of saponification of 100 mol%, that is, having only a hydrophilic hydroxyl group.

As the water-soluble resin, either one of a polyvinyl alcohol resin or a derivative thereof and a polyvinyl ether resin may be used alone, or both of them may be used simultaneously.

(chelating agent)

Chelating agents are materials that can coordinate to metal ions and form metal ion complexes.

Since the chelating agent binds the metal compound (e.g., chromium oxide) derived from the halogenated metal compound to the water-soluble resin to increase the compressive strength of the first corrosion-prevention layer 13, the first corrosion-prevention layer 13 is not embrittled and does not crack or peel when the thickness of the first corrosion-prevention layer 13 exceeds 0.2 μm and is 1.0 μm or less, for example. Therefore, the adhesive strength and adhesion between the separator 14 and the first adhesive layer 12, and the adhesive strength and adhesion between the separator 14 and the layer on the upper layer side thereof can be improved.

The chelating agent has a function of making the water-soluble resin resistant to hydration by chemically reacting with the water-soluble resin or the halogenated metal compound.

Examples of the chelating agent include aminocarboxylic acid chelating agents, phosphonic acid chelating agents, hydroxycarboxylic acids, and (poly) phosphoric acid chelating agents.

(crosslinkable Compound)

The crosslinkable compound is: a compound which can react with the water-soluble resin and form a crosslinked structure. By using such a crosslinkable compound, the water-soluble resin and the crosslinkable compound can form a dense crosslinked structure in the first corrosion prevention layer 13, and the passivation property and the corrosion resistance of the surface of the barrier layer 14 can be further improved.

In the corrosion-preventing treatment agent, either one of the chelating agent and the crosslinkable compound may be used, or both of them may be used. Among these, it is preferable to use either one of the chelating agent and the crosslinkable compound in combination with the above-mentioned halogenated metal compound and water-soluble resin.

The corrosion-preventive treatment agent can be prepared by dissolving a water-soluble resin, a halogenated metal compound, and a chelating agent and/or a crosslinkable compound in a solvent containing water. Water is preferred as the solvent.

The solid content concentration in the corrosion prevention treatment agent may be appropriately determined in consideration of coatability of the first corrosion prevention layer 13, and the like, but may be usually 0.1 to 10% by mass.

The thickness of the first corrosion prevention layer 13 is preferably 0.05 μm or more, and more preferably more than 0.1 μm. By setting the thickness of the first corrosion prevention layer 13 to 0.05 μm or more, the adhesion strength between the separator layer 14 and the first adhesive layer 12 and the adhesion strength between the separator layer 14 and the sealant layer 11 can be improved while providing sufficient corrosion resistance to the battery exterior laminate 10.

The thickness of the first corrosion prevention layer 13 is preferably 1.0 μm or less, and more preferably 0.5 μm or less. By setting the thickness of the first corrosion prevention layer 13 to 1.0 μm or less, the adhesion strength between the separator layer 14 and the first adhesive layer 12 is improved, and the material cost can be reduced.

< isolation layer 14 >

In the laminate 10 for battery exterior packaging, the separator 14 plays an important role in reducing leakage of the contents sealed by the laminate (for example, leakage of the battery). Further, by using a metal having high mechanical strength, when a concave portion for housing a battery is formed by stretch molding using the laminate 10 for battery exterior packaging, the occurrence of pinholes can be reduced, and as a result, leakage of the contents sealed with the laminate (for example, leakage of the battery) can be reduced.

The separator 14 is not particularly limited as long as it is a separator obtained by thinly stretching a metal or an alloy, and examples thereof include metal foils such as aluminum, copper, lead, zinc, iron, nickel, titanium, and chromium; and alloy foils such as stainless steel. The stainless steel foil is not particularly limited as long as it is made of stainless steel such as austenite, ferrite, or martensite. As austenite group, SUS304, 316, 301, etc.; examples of the ferrite include SUS 430; examples of the martensite include SUS 410.

Among them, aluminum foil or stainless steel foil is preferable from the viewpoint of workability, ease of handling, price, strength (puncture strength, tensile strength, etc.), corrosion resistance, etc., and stainless steel foil is particularly preferable from the viewpoint of puncture strength.

The thickness of the isolation layer 14 is preferably 100 μm or less, preferably 5 to 40 μm, more preferably 10 to 30 μm, and particularly preferably 10 to 20 μm. By setting the thickness of the separator 14 to be equal to or greater than the lower limit value, the battery exterior laminate 10 can be provided with sufficient mechanical strength, and when used in a battery such as a secondary battery, the durability of the battery can be improved. Further, by setting the thickness of the separator 14 to be equal to or less than the above upper limit, the battery exterior laminate 10 can be made sufficiently thin, and sufficient stretch processability can be provided.

< second anti-corrosion layer 15 >

The second corrosion prevention layer 15 has the same configuration as the first corrosion prevention layer 13. In this embodiment, the second corrosion prevention layer 15 is provided, but in the present invention, the second corrosion prevention layer 15 has an arbitrary structure.

< second adhesive layer 16 >

The second adhesive layer 16 may have the same structure as the first adhesive layer 12, or may be a layer made of an adhesive such as a normal polyurethane adhesive or epoxy adhesive. The thickness of the second adhesive layer 16 may be, for example, 0.5 to 10 μm. By setting the thickness within this range, the base material layer 17 and the separator layer 14 can be bonded with high adhesion, thereby preventing delamination. In this embodiment, the second adhesive layer 16 is provided, but in the present invention, the second adhesive layer 16 has an arbitrary configuration.

< substrate layer 17 >

The base layer 17 is not particularly limited as long as it has sufficient mechanical strength, and for example, polyester resins such as polyethylene terephthalate (PET), polyethylene naphthalate (PEN), and polybutylene terephthalate (PBT); polyamide resins such as nylon (Ny); polyolefin resins such as extended polypropylene (OPP); and synthetic resin films made of polyether ether ketone (PEEK), polyphenylene sulfide (PPS), and the like. Among them, a PET film is preferable.

The thickness of the base material layer 17 may be, for example, 1 to 50 μm, preferably 1 to 30 μm, and more preferably 3 to 11 μm.

The substrate layer 17 may have a single-layer structure or a multilayer structure. As an example of the substrate layer 17 having a multilayer structure, a two-layer film in which a polyethylene terephthalate (PET) resin film is laminated on a biaxially stretched polyamide resin film (ONy) can be cited. The base layer 17 may have a multilayer structure in which three or more films are laminated.

Further, in the embodiment shown in fig. 1, the base material layer 17 is the outermost layer. Therefore, when the base layer 17 contains a coloring material such as a pigment in addition to the resin, a desired color or design can be obtained.

The base layer 17 is preferably formed of a single-layer or multi-layer film using a heat-resistant resin film having a melting point of 200 ℃. Examples of such a heat-resistant resin film include a PET film, a PEN film, a PBT film, a nylon film, a PEEK film, and a PPS film, but a PET film which is advantageous in terms of cost is particularly preferable. By using such a heat-resistant resin film, the heat resistance of the battery exterior packaging laminate 10 can be improved, and the durability of a battery using the battery exterior packaging laminate 10 can be improved.

In the laminate 10 for battery exterior packaging shown in fig. 1, the base material layer 17 is the outermost layer, but a coating layer may be formed on the outer surface side of the base material layer 17.

The coating layer (first coating layer) is formed of at least one resin selected from the group consisting of a polyurethane resin, an acrylic resin, polyvinylidene chloride, a vinylidene chloride-vinyl chloride copolymer resin, a maleic anhydride-modified polypropylene resin, a polyester resin, an epoxy resin, a phenol resin, a phenoxy resin, a fluorine resin, a cellulose ester resin, a cellulose ether resin, a polyamide resin, a polyphenylene ether resin (PPE), a polyphenylene sulfide resin (PPS), a polyarylether resin (PAE), and a polyetheretherketone resin (PEEK). The coating layer is preferably made of a material having excellent heat resistance. These resins may be used singly or in combination of two or more.

The coating layer is preferably a film cured layer formed by applying a solvent-based coating prepared by dissolving the resin in a common organic solvent and drying.

By forming the coating layer, the insulation properties of the battery exterior laminate 10 are improved, and the surface of the battery exterior laminate 10 can be prevented from being damaged. Further, even when the battery exterior laminate 10 is in contact with the electrolyte solution, changes in appearance (discoloration and the like) can be prevented.

Further, the coating layer can be colored by adding a colorant or a pigment to the solvent-based coating material forming the coating layer. Further, the coating layer may be colored or printed to display characters, graphics, images, patterns, and the like, thereby improving the design feeling.

The thickness of the coating layer may be, for example, 0.1 to 20 μm, preferably 2 to 10 μm.

The thickness of the laminate 10 for battery outer packaging is preferably 10 to 200 μm, more preferably 20 to 100 μm, and still more preferably 30 to 80 μm.

Examples of the battery using the laminate 10 for battery exterior packaging include secondary batteries such as lithium ion batteries as secondary batteries, and batteries using an organic electrolyte as an electrolyte solution such as capacitors such as electric double layer capacitors. The organic electrolyte is usually a medium of a carbonate such as Propylene Carbonate (PC), diethyl carbonate (DEC) or ethylene carbonate, but is not particularly limited thereto.

The laminate for battery exterior packaging of the present invention can be produced by a method comprising the steps of: for example, the step of forming the first anti-corrosion layer 13 on one surface of the separator layer 14, the step of forming the first adhesive layer 12 on the formed first anti-corrosion layer 13, and the step of laminating the laminate by disposing the sealant layer 11 in contact with the formed first adhesive layer 12 (or by disposing the second sealant layer 11 'in contact with the first adhesive layer 12 when the second sealant layer 11' is provided).

The details will be described below.

First, the first corrosion prevention layer 13 is formed on one surface of the stainless steel foil 14.

Specifically, the corrosion-preventing treatment agent is applied to the surface of the barrier layer 14 and then heated and dried. At this time, only the first corrosion prevention layer 13 may be formed by coating the corrosion prevention treatment agent on only one side of the separation layer 14; the second corrosion prevention layer 15 may also be formed simultaneously by coating both sides of the separation layer 14 with a corrosion prevention treatment agent. When the second corrosion prevention layer 15 is provided, the second corrosion prevention layer 15 is preferably formed in a stage before the first adhesive layer 12 and the like are formed, and more preferably formed simultaneously with the first corrosion prevention layer 13.

In the case of forming the first corrosion prevention layer 13 and the second corrosion prevention layer 15 at the same time, it is preferable to dip the separator 14 in the corrosion prevention treatment agent, attach the corrosion prevention treatment agent to both surfaces of the separator 14, and then heat dry the resultant.

Next, the first adhesive layer 12 is formed on the first corrosion prevention layer 13.

Specifically, a layer made of the adhesive is formed on the surface of the stainless steel foil 14 on which the first corrosion prevention layer 13 is provided, and is heated and dried as necessary.

When the adhesive is an adhesive for thermal lamination containing no organic solvent, the component (a) and the component (B) are melt-kneaded to react the two components, and then the resultant is coated on the first corrosion-resistant layer 13 and dried to form the first adhesive layer 12.

The melt-kneading may be carried out by a known apparatus such as a single-screw extruder, a multi-screw extruder, a Banbury mixer, a kneader, or a heated roll kneader. In order to suppress decomposition of the epoxy group during melt kneading, it is preferable that volatile components such as moisture that can react with the epoxy group are removed from the apparatus in advance, and when volatile components are generated during the reaction, they are discharged to the outside of the apparatus as needed by degassing or the like. The acid-modified polyolefin resin having an acid anhydride group as an acidic functional group is preferable because it has high reactivity with an epoxy group and can be reacted under more stable conditions. The heating temperature during melt kneading is preferably selected from the range of 240 to 300 ℃ in order to sufficiently melt the two components without thermally decomposing the components. The kneading temperature can be measured by a method such as bringing a thermocouple into contact with the molten adhesive immediately after extrusion from the melt kneading apparatus.

When the adhesive is an adhesive for dry lamination containing an organic solvent, the first adhesive layer 12 is formed by dissolving the component (a) and the component (B) in the organic solvent, applying the solution on the first corrosion-resistant layer 13, and drying the solution. The formation of the first adhesive layer 12 may be performed in a series of steps using a known dry laminator or the like together with the step of laminating the sealant layer 11 (or the step of laminating the sealant layer 11 via the second sealant layer 11') which will be described later.

Thereafter, the laminate is laminated such that the sealant layer 11 or the second sealant layer 11' having the sealant layer 11 is disposed in contact with the formed first adhesive layer 12. The lamination may be dry lamination or thermal lamination, but dry lamination at 70 to 150 ℃ is preferable. The pressure during dry lamination is preferably 0.1 to 0.5 MPa.

Specifically, a film constituting the sealant layer 11 (and the second sealant layer 11') is prepared in advance, and the film is disposed on the first adhesive layer and then laminated. The temperature for lamination is not particularly limited as long as the sealant layer 11 or the second sealant layer 11', the first corrosion prevention layer 13, and the separator layer 14 are favorably adhered via the first adhesive layer, and may be determined in consideration of the material or melting point of the adhesive constituting the first adhesive layer 12. The temperature during dry lamination is usually 70 to 150 ℃, preferably 80 to 120 ℃.

The step of forming the first adhesive layer 12 and the step of disposing and (dry) laminating the sealant layer 11 (and the second sealant layer 11') may be performed in a series of steps using a known (dry) laminating apparatus.

The second anticorrosive layer 15, the second adhesive layer 16, and the base material layer 17 are not particularly limited, and for example, the second adhesive layer 16 is formed on the base material layer 17 in advance to form a laminate composed of two layers. Thereafter, the two-layer laminate and the laminate having the sealant layer 11 (and the second sealant layer 11'), the first adhesive layer 12, the first corrosion prevention layer 13, the separator 14, and the second corrosion prevention layer 15 are dry-laminated so that the second adhesive layer 16 and the second corrosion prevention layer 15 are in contact with each other, whereby the laminate 10 for battery exterior packaging having eight layers can be prepared.

While one embodiment of the present invention has been described above with reference to the laminate 10 for battery exterior packaging shown in fig. 1, the technical scope of the present invention is not limited to the above-described embodiment, and various modifications may be made without departing from the scope of the present invention.

Further, another layer may be provided on the side of the sealant layer 11 not in contact with the second sealant layer 11' or the first adhesive layer 12, or on the side of the base layer 17 not in contact with the second adhesive layer 16, so that nine or ten layers or more may be formed.

In the battery exterior packaging laminate 10 shown in fig. 1, the first corrosion prevention layer 13 and the second corrosion prevention layer 15 are formed on both surfaces of the separator layer 14, but in the battery exterior packaging using the battery exterior packaging laminate 10, the sealant layer 11 side that can be in contact with the electrolyte solution or the like is on the inner surface side. Therefore, the corrosion prevention layer is formed at least on the sealant layer 11 side of the separator layer 14. That is, the second corrosion prevention layer 15 may be omitted from the battery exterior packaging laminate 10 shown in fig. 1.

In the laminate 10 for battery exterior packaging shown in fig. 1, the base material layer 17 and the second adhesive layer 16 are in direct contact, but a printed layer for improving design may be provided on the inner surface side of the base material layer 17.

The printing layer may have the same structure as the coating layer.

In the battery exterior laminate 10 shown in fig. 1, the second sealant layer 11 'is provided, but the second sealant layer 11' has an arbitrary configuration and may be omitted. When the laminate 10 for battery exterior packaging of the present invention has only the sealant layer 11 as a layer having a sealing function, it may have sufficient adhesive strength required for the battery exterior packaging after heat sealing.

In the battery exterior packaging laminate 10 shown in fig. 1, the first adhesive layer 12 is provided, but the first adhesive layer 12 may be omitted. When the first adhesive layer 12 is not provided, a laminate can be produced without the first adhesive layer 12 being interposed by arranging a single sealant layer 11 or the sealant layer 11 provided with the second sealant layer 11' on the separator layer 14 provided with the first corrosion prevention layer 13 and heating and laminating the laminate.

[ Battery outer packaging body ]

A battery exterior package according to a second aspect of the present invention is a battery exterior package including the laminate for battery exterior packaging according to the first aspect, and has an internal space for housing a battery, and the side of the sealant layer of the laminate for battery exterior packaging is the side of the internal space. Specifically, the laminate for battery exterior packaging of the first aspect is obtained by molding the laminate for battery exterior packaging of the first aspect into a desired shape such that the sealant layer faces the internal space, and sealing the end portions as necessary.

The shape, size, and the like of the battery exterior body are not particularly limited, and may be appropriately determined according to the type of battery used.

The battery exterior body may be formed of one member, or may be formed by combining two or more members (for example, a container body and a lid) as will be described later with reference to fig. 2.

[ method for producing Battery outer packaging body ]

A method for producing a battery exterior body according to a third aspect of the present invention includes: a molding step of pressing the first member made of the laminate for battery exterior packaging of the first aspect from the sealant layer side of the laminate for battery exterior packaging to form a container main body having a concave portion; an assembling step of overlapping the sealant layer of the container body and a sealant layer of a second member having the laminate for battery exterior packaging as a constituent material; and a joining step of heat-sealing the overlapped sealant layers to join one sealant layer to the other sealant layer. The heat seal temperature is lower than the mpA and higher than the mpB.

The third embodiment of the production method will be described with respect to the case of producing the battery exterior body 20 shown in fig. 2 to 3.

The battery exterior body 20 is formed by overlapping the container body 30 composed of the battery exterior laminate 10 according to the first embodiment of the present invention and the lid 33 composed of the battery exterior laminate 10, and heat-sealing the peripheral edge 29.

First, the laminate 10 for a battery outer package is subjected to drawing (stretch molding) using an appropriate die and a press machine to form the container body 30. At this time, the side facing the internal space (concave portion) formed by the drawing process is set to be the side of the sealant layer 11 of the battery exterior body 10.

Next, the obtained container body 30 and the lid 33 composed of the battery exterior laminate 10 are combined so that the sealant layers 11 are overlapped with each other. Since the container body 30 faces the internal space on the side of the sealant layer 11, the internal space can be formed by combining the sealant layer of the container body 30 and the sealant layer of the planar lid portion 33.

Then, the stacked sealant layers (i.e., the flange portion 32 of the container body 30 and the peripheral edge portion 34 of the lid portion 33) are thermally welded to each other at a temperature higher than mpA and lower than mpB, and the sealant layers are joined to each other, whereby the battery exterior body 20 shown in fig. 2 is obtained. That is, in the battery shown in fig. 3, by covering the lid 33 on the upper surface of the container main body 30, the recess 31 and the lid 33 can form an internal space for housing the battery.

The temperature (t) during hot melt connection is mpA < t) < mpB, preferably 125-155 ℃, more preferably 130-155 ℃, and further preferably 135-155 ℃.

[ Battery ]

A battery according to a fourth aspect of the present invention includes the battery exterior packaging body according to the second aspect.

Examples of the battery include secondary batteries such as lithium ion batteries as secondary batteries, and batteries using an organic electrolyte as an electrolytic solution such as capacitors such as electric double layer capacitors. Since the laminate for battery exterior packaging of the present invention has high electrolyte resistance, even when used in a battery exterior packaging containing LiPF₆And the like, and can operate well.

As an example, a perspective view of the secondary battery 40 is shown in fig. 2. The secondary battery 40 is a battery in which the lithium ion battery 27 is housed in the battery outer packaging container 20.

The battery exterior container 20 is formed by stacking a container body 30 composed of the battery exterior laminate 10 according to the first embodiment of the present invention and a lid 33 composed of the battery exterior laminate 10, and heat-sealing the peripheral edge 29. Reference numeral 28 denotes electrode leads connected to the positive electrode and the negative electrode of the lithium ion battery 27.

The battery shown in fig. 2 may be prepared in the following manner.

First, as shown in fig. 3 (a), the battery exterior laminate 10 is pressed from the sealant layer side of the battery exterior laminate 10 by stretch molding or the like to be formed into a tray shape having a concave portion 31, thereby obtaining a container body 30. The depth of the recess 31 may be 2mm or more, for example.

A lithium ion battery (lithium ion battery 27 in fig. 2) is housed in the recess 31 of the container main body 30.

Next, as shown in fig. 3 (b), the lid 33 composed of the battery outer packaging laminate 10 is superimposed on the container body 30, and the flange portion 32 of the container body 30 and the peripheral edge portion 34 of the lid 33 are heat-sealed, whereby the secondary battery 40 shown in fig. 2 is obtained. That is, in the battery shown in fig. 3, by covering the lid 33 on the upper surface of the container main body 30, an internal space for housing the battery is formed by the recess 31 and the lid 33.

In addition, the battery of the present invention can also be prepared in the following manner.

First, as shown in fig. 4 (a), a rectangular battery exterior laminate 50 is molded by pressing a portion of one end side in the longitudinal direction from the sealant layer side of the battery exterior laminate 50 by stretch molding or the like, thereby obtaining a molded body 55 having a concave portion 51. The depth of the recess 51 may be, for example, 2mm or more.

Next, although not shown in the drawings, a lithium ion battery (lithium ion battery 27 in fig. 2) is housed in the concave portion 51 of the molded body 55.

Next, a portion of the other end side of the molded body 55 where the concave portion 51 is not formed is folded toward the sealant layer side so as to form a folding line L extending in the width direction of the molded body 55. At this time, in the molded body 55, a region on the side of the concave portion 51 with respect to the folding line L is set as a "first region 551"; a region on the opposite side of the recess 51 with respect to the folding line L is referred to as a "second region 552".

Next, the sealant layer on the periphery 52 of the concave portion 51 in the first region 551 and the sealant layer (peripheral portion 54) overlapping the periphery 52 in the second region 552 are overlapped. Thereby, the second region 552 overlaps the concave portion 51 of the first region 551.

Next, as shown in fig. 4 (b), the sealant layer around the recessed portion 51 and the sealant layer of the second region 552 are heat-sealed, whereby the secondary battery 60 having the battery exterior body formed of one member can be obtained. That is, in the battery shown in fig. 4 (b), the second region 552 covers the upper surface of the recess 51, whereby an internal space for housing the battery can be formed by the recess 51 and the second region 552.

Examples

The present invention will be described in further detail with reference to examples below, but the present invention is not limited to these examples.

Examples 1 to 11 and comparative examples 1 to 5

< examples 1 to 8, comparative examples 1 to 5 >

First, the metal foils shown in table 1 were prepared. The metal foil was coated with an anticorrosive treatment agent on both sides and dried by heating in an oven at 200 ℃ to form a first anticorrosive layer and a second anticorrosive layer each having a thickness of 0.1 μm on both sides. An anticorrosive treatment agent in which chromium fluoride, phosphoric acid and polyvinyl alcohol are mixed is used.

Next, a first adhesive was applied to the first corrosion prevention layer to form a first adhesive layer having a thickness of 3 μm. The first adhesive was obtained by melting and kneading 90 mass% of maleic anhydride-modified polypropylene and 10 mass% of a novolac epoxy resin having a bisphenol a structure (product name: jER157S70, viscosity 80, epoxy equivalent 210) in toluene at room temperature so that the amount of solid content was 10% and stirring and dissolving the mixture.

Thereafter, a sealing film obtained using the sealant layer composition shown in table 1 and the first adhesive layer in the laminate obtained above were laminated by dry lamination at 100 ℃.

Further, a second adhesive layer (thickness: 3 μm) made of a polyurethane adhesive was applied on a base material layer made of a biaxially stretched polyamide (nylon) resin film having a thickness of 25 μm and a black color having a thickness of 6 μm, and molding was performed.

The second adhesive layer was laminated on the second anti-corrosion layer in the laminate obtained above at 80 ℃ by dry lamination to obtain a laminate for battery exterior packaging.

< example 9 >

A laminate for battery exterior packaging was obtained in the same manner as in examples 1 to 8, except that a first adhesive, which was obtained by melt-mixing 90 mass% of maleic anhydride-modified polypropylene and 10 mass% of "MODIPER a 4100" (trade name; manufactured by nippon oil co., ltd.; ethylene-glycidyl methacrylate copolymer, graft polymer with polystyrene, and the proportion of glycidyl methacrylate monomer to the total monomers in the main chain was 30 mass%), was used as the first adhesive.

< example 10 >

A laminate for battery exterior packaging was obtained in the same manner as in examples 1 to 8, except that a first adhesive, which was a resin obtained by copolymerizing styrene and 2-isopropenyl-2-oxazoline (number average molecular weight: 7 ten thousand), was used as the adhesive, and that 90 mass% of maleic anhydride-modified polypropylene and 10 mass% of "EPOCROS RPS-1005" (trade name, manufactured by japan catalyst corporation) were melt-mixed.

[ Table 1]

In table 1, the abbreviations have the following meanings. [] The numerical value in (b) is the amount added (parts by mass).

A-1: block polypropylene (melting point 162 ℃ C.)

A-2: block polypropylene (melting point 135 ℃ C.)

B-1: atactic polypropylene (melting point 140 ℃ C.)

B-2: atactic polypropylene (melting point 130 ℃ C.)

B-3: atactic polypropylene (melting point 120 ℃ C.)

C-1: olefin elastomer (melting point 130 ℃ C.)

C-2: olefin elastomer (melting point 80 ℃ C.)

C-3: olefin elastomer (melting point 120 ℃ C.)

AL: aluminum foil

SUS: stainless steel foil

(Heat resistance test)

The laminate for battery exterior packaging prepared in each example was heat-sealed at 0.3MPa · 150 ℃ · 2 seconds, T-peel was performed in an environment of 23 ℃, and the results thereof were evaluated on the following criteria, and are shown in table 1 as "heat resistance".

A: 50N/15mm or more

B: less than 50N/15mm and 40N/15mm or more

C: less than 40N/15mm and more than 30N/15mm

D: less than 30N/15mm

(Low temperature sealing test)

The laminate for battery exterior packaging prepared in each example was heat-sealed at 0.3MPa 140 ℃.3 seconds, T-peel was performed at 23 ℃ and evaluated according to the following criteria, and the results are shown in table 1 as "low-temperature sealability".

O: 40N/15mm or more

X: less than 40N/15mm

(Cold resistance test)

The laminate for battery exterior packaging prepared in each example was heat-sealed at 0.3MPa, 155 ℃ and 3 seconds, and then T-peeled at-30 ℃ to evaluate the results on the following criteria, and the results are shown in table 1 as "cold resistance".

A: 40N/15mm or more

B: less than 40N/15mm and 20N/15mm or more

C: less than 20N/15mm

(thermal shock test)

The battery exterior laminate prepared in each example was heat sealed at 0.3MPa 155 ℃ for 3 seconds. Thereafter, a heat shock test was performed by repeating 100 cycles of 60 minutes at-30 ℃ and 60 minutes at 80 ℃. The appearance of the laminate for battery exterior packaging after the heat shock test was visually observed, and the T-peel strength was measured under conditions of 15mm width, 300mm/min, and 180-degree peel. The evaluation was performed according to the following criteria, and the results are shown in table 1 as "thermal shock test resistance".

A: when the appearance was visually confirmed, no discoloration of the sealant layer was observed, and the T-peel strength was not changed from that before the thermal shock test

B: when the appearance was visually confirmed, the sealant layer was partially discolored, but the T-peel strength was not changed from that before the heat shock test

C: when the appearance was visually confirmed, the sealant layer was partially discolored, and the T-peel strength was higher than that before the thermal shock test, and the peeling was liable to deteriorate

From the results shown in table 1, it was confirmed that examples 1 to 11 using the laminate for outer package of battery of the present invention have excellent durability (adhesiveness) in various conditions as compared with comparative examples 1 to 6, and the excellent adhesiveness was obtained even when heat-sealed at a relatively low temperature.

[ example 11]

In the same manner as in example 2 above, a battery exterior laminate was obtained.

[ examples 12 to 13]

A battery exterior laminate was obtained in the same manner as in examples 1 to 8, except that a two-layer sealing film having a sealant layer 11 and a second sealant layer 11' was used as the sealing film.

Specifically, as the outermost layer (innermost layer) sealant layer corresponding to the sealant layer 11, a composition having the same composition as that of the sealant layer of example 2 was used. Further, as the inner sealant layer corresponding to the second sealant layer 11', a composition having a composition shown in table 2 was used. A two-layer sealant film was prepared by coextruding the two compositions. Then, the double-layer sealing film was laminated by dry lamination so that the second sealant layer of the sealing film faced the first adhesive layer.

(seal Strength)

The laminate for battery exterior packaging prepared in each example was heat-sealed at 0.4MPa, 155 ℃ for 3 seconds, and T-peel was performed at 23 ℃ to evaluate the results on the basis of the following criteria, and the results are shown in table 2 as "seal strength".

A: 40N/15mm or more

B: less than 40N/15mm

[ Table 2]

From the results shown in table 2, it was confirmed that the sealing strength could be further improved by having the second sealant layer.

Claims

1. A laminate for battery exterior packaging, comprising at least a sealant layer, a first adhesive layer, a separator layer made of a metal foil, and a base material layer in this order,

the sealant layer is composed of block polypropylene, random polypropylene and olefin elastomer,

the block polypropylene is a block copolymer consisting of polypropylene and ethylene-propylene copolymer,

the random polypropylene is a propylene-ethylene random copolymer,

when the content ratios by mass of the block polypropylene, random polypropylene and olefin elastomer are A, B, C in order, and the melting points of the block polypropylene, random polypropylene and olefin elastomer are mpA, mpB and mpC in order, the sealant layer satisfies the relationships of the following expressions (1) to (4):

A＞B (1)

A＞C (2)

A+B+C＝100 (3)

mpA＞mpB≧mpC (4)。

2. the laminate for battery exterior packaging according to claim 1, wherein the sealant layer contains 35 to 80 mass% of block polypropylene, 10 to 45 mass% of random polypropylene, and 10 to 40 mass% of olefin elastomer.

3. The laminate for battery exterior packaging according to claim 1 or 2, further comprising a second sealant layer between the sealant layer and the first adhesive layer.

4. The laminate for battery exterior packaging according to claim 1 or 2, wherein the first adhesive layer contains a maleic acid-modified polypropylene and a compound having an epoxy group or an oxazoline group.

5. The laminate for battery exterior packaging according to claim 4, wherein the compound having an epoxy group is a novolac-type epoxy resin or an epoxy group-containing polyolefin resin.

6. The laminate for battery exterior packaging according to claim 4, wherein the compound having an oxazoline group is an oxazoline group-containing styrene resin.

7. A battery exterior package comprising the laminate for battery exterior packaging according to any one of claims 1 to 6, characterized by having an internal space for housing a battery, wherein the side of the sealant layer of the laminate for battery exterior packaging is the side of the internal space.

8. A method for producing a battery exterior package, comprising:

a molding process comprising: pressing the first member made of the laminate for battery external packaging according to any one of claims 1 to 6 from the sealant layer side of the laminate for battery external packaging to form a container body having a concave portion;

an assembly process comprising: combining the sealant layer of the container body and the sealant layer of the second member using the laminate for battery exterior packaging as a constituent material so as to overlap each other; and

a bonding process comprising: hot melt joining the superposed sealant layers to join one sealant layer to the other.

9. A method for producing a battery exterior package, comprising:

a molding process comprising: forming a concave portion by pressing a part of a member made of the laminate for battery external packaging according to any one of claims 1 to 6 from the sealant layer side of the laminate for battery external packaging;

an assembly process comprising: folding the member toward the sealant layer side in a region where the concave portion is not formed, and overlapping the sealant layer in a periphery of the concave portion in a first region on the concave portion side with respect to the formed folding line and the sealant layer in a second region on an opposite side of the concave portion with respect to the folding line; and

10. The method of manufacturing a battery exterior packaging body according to claim 8 or 9, wherein the temperature at the time of the thermal fusion bonding is lower than the mpA and higher than the mpB.

11. A battery comprising the battery exterior package according to claim 7.