Liquid storage bag, transport container and liquid-filled transport container

Abstract

To provide a liquid storage bag, a transport container and a liquid-filled transport container capable of preventing solvent from leaking from the liquid storage bag.SOLUTION: A liquid storage bag 10 has an outer layer film 20 and an inner layer film 30 located inside an outer film. The outer film 20 has a water vapor barrier layer 21 and a first sealant layer 26 located inside the water vapor barrier layer 21, and the inner film 30 has a solvent penetration inhibiting layer 31, a second sealant layer 35 located outside the solvent penetration inhibiting layer 31, a third sealant layer 38 located inside the solvent penetration inhibiting layer 31. A part of the first sealant layer 26 and a part of the second sealant layer 35 are joined to each other to form an unsealed space SP between the outer layer film 20 and the inner layer film 30.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present disclosure relates to a liquid storage bag, a transport container, and a transport container containing a liquid. [Background technology]

[0002] Lithium-ion batteries are charged and discharged by the movement of lithium ions between the positive and negative electrodes. In the manufacturing process of lithium-ion batteries, a conductive assistant containing carbon black is dispersed in a solvent in which a binder is dissolved to form a slurry. An organic solvent called N-methyl-2-pyrrolidone (NMP) is used as the solvent.

[0003] Incidentally, the slurry containing carbon black is transported from a slurry production factory to a lithium ion battery production factory. In this case, the slurry is generally filled in a large container such as an IBC container or a resin drum, and transported in this state. However, since the slurry contains carbon black, the container that transports the slurry becomes colored by the carbon black, making it difficult to reuse the container.

[0004] In order to prevent the container from being discolored, it is possible to place a polyethylene bag in the container in advance and fill the bag with the slurry. However, when a polyethylene bag is used, there is a risk that a highly permeable solvent such as NMP may leak between the bag and the container. If the solvent leaks from the bag, the amount of solvent in the container decreases. This may cause a change in the concentration of carbon black in the slurry in the container. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent Publication No. 2021-79640 Summary of the Invention [Problem to be solved by the invention]

[0006] The present disclosure provides a liquid storage bag, a transport container, and a transport container containing liquid, which are capable of preventing a solvent from leaking out of the liquid storage bag. [Means for solving the problem]

[0007] The embodiments of the present disclosure relate to the following [1] to

[10] .

[0008] [1] A liquid storage bag comprising an outer layer film and an inner layer film located on the inside of the outer layer film, the outer layer film having a water vapor barrier layer and a first sealant layer located on the inside of the water vapor barrier layer, the inner layer film having a solvent permeation suppression layer, a second sealant layer located on the outside of the solvent permeation suppression layer, and a third sealant layer located on the inside of the solvent permeation suppression layer, a portion of the first sealant layer and a portion of the second sealant layer being joined to each other, and an unsealed space being formed between the outer layer film and the inner layer film.

[0009] [2] A liquid storage bag as described in [1], comprising a pair of the outer layer films and a pair of the inner layer films, wherein the pair of the inner layer films are overlapped with each other and a portion of the third sealant layer of one of the inner layer films and a portion of the third sealant layer of the other inner layer film are joined to each other.

[0010] [3] The liquid storage bag described in [1] or [2], wherein the water vapor barrier layer includes, from the outside, a first substrate layer, a first deposition layer, and a first barrier coat layer.

[0011] [4] A liquid storage bag described in any one of [1] to [3], wherein the solvent permeation prevention layer includes, from the inside, a second substrate layer, a second vapor deposition layer, and a second barrier coat layer.

[0012] [5] A liquid storage bag described in any one of [1] to [4], wherein the water vapor barrier layer and the first sealant layer are bonded to each other by a first adhesive resin layer.

[0013] [6] A liquid storage bag described in any one of [1] to [5], wherein the solvent permeation suppression layer and the second sealant layer are bonded to each other by an adhesive layer.

[0014] [7] A liquid storage bag described in any one of [1] to [6], wherein the solvent permeation suppression layer and the third sealant layer are bonded to each other by a second adhesive resin layer.

[0015] [8] A transport container comprising a container body and a liquid storage bag described in any one of [1] to [7] contained within the container body.

[0016] [9] A liquid-containing transport container comprising the transport container described in [8] and a liquid contained in the liquid storage bag of the transport container, the liquid including a solvent.

[0017]

[10] The liquid-containing transport container described in [9], wherein the solvent is N-methyl-2-pyrrolidone. Effect of the Invention

[0018] According to this embodiment, it is possible to prevent the solvent from leaking out of the liquid storage bag. [Brief description of the drawings]

[0019] [Figure 1] FIG. 1 is a perspective view showing a liquid-containing transport container according to one embodiment. [Diagram 2] FIG. 2 is a cross-sectional view showing a liquid storage bag according to one embodiment. [Diagram 3] FIG. 3 is a cross-sectional view (enlarged view of part III in FIG. 2) showing the layer structure of the liquid storage bag according to the embodiment. [Figure 4] 4(a)-(c) are cross-sectional views showing a first half of a manufacturing method for a liquid storage bag according to one embodiment. [Diagram 5] 5(a)-(d) are cross-sectional views showing a second half of the manufacturing method for the liquid storage bag according to the embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0020] Each embodiment will be specifically described below with reference to the drawings. Each of the figures shown below is a schematic diagram. Therefore, the size and shape of each part are appropriately exaggerated to facilitate understanding. In addition, it is possible to carry out appropriate modifications within the scope of the technical idea. In each of the figures shown below, the same parts are given the same reference numerals, and some detailed descriptions may be omitted. In addition, the numerical values ​​such as dimensions of each member and the material names described in this specification are examples of embodiments, and are not limited thereto, and can be appropriately selected and used. In this specification, terms that specify shapes and geometric conditions, such as parallel, orthogonal, and vertical, include substantially the same state in addition to their strict meanings. In addition, for convenience of explanation, the terms "upper" and "lower" may be used in the explanation, but the up-down direction may be reversed.

[0021] [Shipping container] The configuration of a transportation container 50 according to this embodiment will be described with reference to Fig. 1. Fig. 1 is a perspective view showing a transportation container 50 according to this embodiment.

[0022] As shown in FIG. 1, a transport container 50 according to this embodiment includes a container body 51 and a liquid storage bag 10 accommodated in the container body 51. The capacity of the container body 51 may be 100 L or more and 10,000 L or less. The shape of the container body 51 may be, for example, a rectangular parallelepiped. The container body 51 may be a large container such as an IBC (Intermediate Bulk Containers) container. Alternatively, the shape of the container body 51 may be, for example, a cylindrical shape. The container body 51 may be a large container such as a plastic drum (resin drum).

[0023] The liquid storage bag 10 is accommodated in the container body 51 so as to conform to the shape of the inner surface of the container body 51. When accommodated in the container body 51, the liquid storage bag 10 may expand into, for example, a rectangular parallelepiped or cylindrical shape. The liquid storage bag 10 may be equipped with a spout and / or a cap (not shown). The configuration of the liquid storage bag 10 will be described in detail later.

[0024] Liquid LQ is contained in the liquid storage bag 10. The liquid LQ may be, for example, a slurry used in producing a lithium ion battery. The slurry is obtained by dispersing an active material and a conductive assistant in a solvent in which a binder is dissolved. For example, polyvinylidene fluoride (PVDF) may be used as the binder. For example, the active material may be a metal oxide containing lithium ions that plays a role in taking in / releasing lithium ions. For example, carbon black may be used as the conductive assistant. Furthermore, an organic solvent such as N-methyl-2-pyrrolidone (hereinafter also referred to as NMP) may be used as the solvent.

[0025] In this embodiment, a liquid-containing transport container 50A is also provided, which includes the transport container 50 and the liquid LQ contained in the liquid storage bag 10 of the transport container 50.

[0026] [Liquid storage bag] Next, the configuration of the liquid storage bag 10 according to the present embodiment will be described with reference to Figures 2 and 3. Figure 2 is a cross-sectional view showing the liquid storage bag 10 according to the present embodiment, and Figure 3 is a partially enlarged cross-sectional view (enlarged view of part III in Figure 2) showing the layer configuration of the liquid storage bag 10 according to the present embodiment.

[0027] In this embodiment, "inside" and "inner side" refer to the side facing inward of the liquid storage bag 10. In other words, "inside" and "inner side" refer to the side in which the above-mentioned liquid LQ is contained. "Outside" and "outer side" refer to the side facing outward of the liquid storage bag 10. In other words, "outside" and "outer side" refer to the side opposite to the side in which the above-mentioned liquid LQ is contained.

[0028] As shown in FIG. 2, the liquid storage bag 10 is a double-layered bag having an outer film 20 and an inner film 30 positioned inside the outer film 20.

[0029] In this embodiment, the liquid storage bag 10 includes a pair of outer layer films 20 and a pair of inner layer films 30. The pair of outer layer films 20 and the pair of inner layer films 30 are overlapped with each other and joined along the periphery of the pair of outer layer films 20 and the pair of inner layer films 30. Specifically, a part of a first sealant layer 26 (described later) of one outer layer film 20 and a part of a second sealant layer 35 (described later) of one inner layer film 30 are joined to each other. Also, a part of a third sealant layer 38 (described later) of one inner layer film 30 and a part of a third sealant layer 38 (described later) of the other inner layer film 30 are joined to each other. Furthermore, a part of a first sealant layer 26 (described later) of the other outer layer film 20 and a part of a second sealant layer 35 (described later) of the other inner layer film 30 are joined to each other.

[0030] However, the liquid storage bag 10 may include one outer layer film 20 and one inner layer film 30 laminated together. In this case, the outer layer film 20 and the inner layer film 30 may be folded back partway. The inner sides of the inner layer films 30 may be joined to each other at the edge away from the folded back side.

[0031] 3, the outer layer film 20 has a water vapor barrier layer 21, a first adhesive resin layer 25, and a first sealant layer 26. The first sealant layer 26 is located inside the water vapor barrier layer 21. The water vapor barrier layer 21 includes, from the outside, a first base material layer 22, a first deposition layer 23, and a first barrier coat layer 24. The water vapor barrier layer 21 and the first sealant layer 26 are bonded to each other by the first adhesive resin layer 25.

[0032] The inner layer film 30 has a solvent permeation suppression layer 31, a second sealant layer 35, an adhesive layer 36, a second adhesive resin layer 37, and a third sealant layer 38. The second sealant layer 35 is located outside the solvent permeation suppression layer 31. The third sealant layer 38 is located inside the solvent permeation suppression layer 31. The solvent permeation suppression layer 31 includes, in order from the inside, a second base material layer 32, a second vapor deposition layer 33, and a second barrier coat layer 34. The solvent permeation suppression layer 31 and the second sealant layer 35 are bonded to each other by an adhesive layer 36. The solvent permeation suppression layer 31 and the third sealant layer 38 are bonded to each other by a second adhesive resin layer 37. As described above, a part (outer edge) of the first sealant layer 26 and a part (outer edge) of the second sealant layer 35 are joined to each other. As a result, an unsealed space SP is formed between the outer layer film 20 and the inner layer film 30.

[0033] Next, each layer constituting the liquid storage bag 10 will be described.

[0034] (Water vapor barrier layer) As described above, the water vapor barrier layer 21 includes, in order from the outside, the first base material layer 22, the first vapor deposition layer 23, and the first barrier coat layer 24. The first base material layer 22 is located as the outermost layer of the liquid storage bag 10. The first vapor deposition layer 23 is laminated directly on the first base material layer 22. The first barrier coat layer 24 is laminated directly on the first vapor deposition layer 23.

[0035] (1st base layer) The first base material layer 22 is a layer that prevents water vapor from penetrating from the outside to the inside of the liquid storage bag 10. The first base material layer 22 may be a layer that supports the first sealant layer 26 and the like and increases the strength of the entire outer layer film 20. Examples of materials that can be used to form the first base material layer 22 include a polyamide resin such as nylon, or a film or sheet of a polyester resin such as polyethylene terephthalate or polybutylene terephthalate, and others.

[0036] As the above-mentioned resin film or sheet, an unstretched film may be used, or a stretched film that has been stretched uniaxially or biaxially may be used.

[0037] The thickness of the first base layer 22 may be, for example, not less than 5 μm and not more than 50 μm.

[0038] (1st vapor deposition layer) The first vapor-deposited layer 23 is a layer for suppressing the transmission of water vapor, etc. For example, a material having gas barrier properties against water vapor, etc. may be used as the first vapor-deposited layer 23. Specifically, the first vapor-deposited layer 23 may be a vapor-deposited thin layer of metal such as aluminum, tin, lead, copper, iron, nickel, or an alloy thereof.

[0039] When a metal vapor-deposited layer of aluminum is used as the first vapor-deposited layer 23, the thickness of the first vapor-deposited layer 23 may be 50 Å or more and 3000 Å or less, and in particular, 100 Å or more and 2000 Å or less.

[0040] The first vapor deposition layer 23 may be a transparent vapor deposition layer that can be formed by a conventionally known method. In this case, the first vapor deposition layer 23 may be a transparent vapor deposition layer made of a vapor deposition layer of an inorganic oxide. In this way, the first vapor deposition layer 23 is a transparent vapor deposition layer, so that it is possible to impart or improve gas barrier properties that prevent the permeation of water vapor and the like while maintaining the permeability of the contents.

[0041] The transparent vapor deposition layer may be, for example, a vapor deposition layer of an oxide of silicon (Si), aluminum (Al), magnesium (Mg), calcium (Ca), potassium (K), tin (Sn), sodium (Na), boron (B), titanium (Ti), lead (Pb), zirconium (Zr), yttrium (Y), or the like.

[0042] (First barrier coat layer) The first barrier coat layer 24 is a film that functions as a layer that suppresses the transmission of water vapor, etc. 1 n M(OR2 ) m (In the formula, R 1 , R 2 represents an organic group having 1 to 8 carbon atoms, M represents a metal atom, n represents an integer of 0 or more, m represents an integer of 1 or more, and n+m represents the atomic valence of M. The gas barrier composition contains at least one alkoxide represented by the formula (I) and a polyvinyl alcohol resin and / or an ethylene-vinyl alcohol copolymer, and is further polycondensed by a sol-gel method in the presence of a sol-gel catalyst, an acid, water, and an organic solvent.

[0043] The above general formula R 1 n M(OR 2 ) m As the alkoxide represented by the formula (I), at least one of the following can be used: a partial hydrolyzate of an alkoxide, and a condensate of the hydrolysis of an alkoxide. In addition, the partial hydrolyzate of the alkoxide does not need to have all of the alkoxy groups hydrolyzed, and may be one in which one or more are hydrolyzed, or a mixture thereof. As the condensate of the hydrolysis of an alkoxide, a dimer or higher of the partially hydrolyzed alkoxide, specifically, a dimer to hexamer, is used.

[0044] The above general formula R 1 n M(OR 2 ) m In the alkoxide represented by the formula (I), the metal atom represented by M can be silicon, zirconium, titanium, aluminum, or the like. Preferred metals include silicon and titanium. In the present disclosure, the alkoxide can be used alone or in the form of a mixture of two or more different metal atoms in the same solution.

[0045] In addition, the above general formula R 1 n M(OR 2 ) m In the alkoxide represented by the formula: 1Specific examples of the organic group represented by the general formula R include alkyl groups such as methyl, ethyl, n-propyl, i-propyl, n-butyl, i-butyl, sec-butyl, t-butyl, n-hexyl, n-octyl, and the like. 1 n M(OR 2 ) m In the alkoxide represented by the formula: 2 Specific examples of the organic group represented by the formula (1) include a methyl group, an ethyl group, an n-propyl group, an i-propyl group, an n-butyl group, a sec-butyl group, etc. In addition, these alkyl groups may be the same or different in the same molecule.

[0046] When preparing the gas barrier composition, for example, a silane coupling agent may be added. As the silane coupling agent, a known organoalkoxysilane containing an organic reactive group may be used. In the present embodiment, in particular, an organoalkoxysilane having an epoxy group is preferably used, and specifically, for example, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, etc. may be used. The above-mentioned silane coupling agents may be used alone or in combination of two or more kinds.

[0047] The thickness of the first barrier coating layer 24 may be, for example, not less than 10 Å and not more than 500 Å.

[0048] (1st adhesive resin layer) The first adhesive resin layer 25 is a layer located between the water vapor barrier layer 21 and the first sealant layer 26. The first adhesive resin layer 25 is a layer that bonds the water vapor barrier layer 21 and the first sealant layer 26 together.

[0049] The first adhesive resin layer 25 includes a thermoplastic resin. The first adhesive resin layer 25 can be formed by, for example, a melt extrusion lamination method or a sand lamination method. Examples of the thermoplastic resin that can be used for the first adhesive resin layer 25 include polyolefin resins such as polyethylene resins and polypropylene resins, cyclic polyolefin resins, copolymer resins, modified resins, or mixtures (including alloys) containing these resins as main components. Examples of polyolefin resins include low-density polyethylene (LDPE), medium-density polyethylene (MDPE), high-density polyethylene (HDPE), linear low-density polyethylene (LLDPE), polypropylene (PP), ethylene-α-olefin copolymers polymerized using a metallocene catalyst, random or block copolymers of ethylene-polypropylene, ethylene-vinyl acetate copolymer (EVA), ethylene-acrylic acid copolymer (EAA), ethylene-ethyl acrylate copolymer (EEA), ethylene-methacrylic acid copolymer (EMAA), ethylene-methyl methacrylate copolymer (EMMA), ethylene-maleic acid copolymer, ionomer resins, and acid-modified polyolefin resins obtained by modifying the above-mentioned polyolefin resins with unsaturated carboxylic acids such as acrylic acid, methacrylic acid, maleic acid, maleic anhydride, fumaric acid, and itaconic acid in order to improve adhesion between layers. In addition, resins obtained by graft-polymerizing or copolymerizing unsaturated carboxylic acids, unsaturated carboxylic anhydrides, and ester monomers with polyolefin resins can be used. These materials can be used alone or in combination of two or more. Examples of cyclic polyolefin resins that can be used include cyclic polyolefins such as ethylene-propylene copolymers, polymethylpentene, polybutene, and polynorbornene. These resins can be used alone or in combination of two or more.

[0050] The adhesive resin constituting the first adhesive resin layer 25 may be a resin composition containing one or more compounds selected from the group consisting of epoxy group-containing compounds, silane group-containing compounds, carboxylic acid group-containing compounds, and acid anhydride-containing compounds, and for example, a polyethylene-based resin or a polypropylene-based resin can be used.

[0051] The polyethylene-based resin constituting the adhesive resin of the first adhesive resin layer 25 is an ethylene homopolymer, or an ethylene-α-olefin copolymer, or a composition thereof, and the molecular chain may be linear or may have a long chain branch having 6 or more carbon atoms.

[0052] In the first adhesive resin layer 25, examples of the ethylene homopolymer include medium- and low-pressure ethylene homopolymer and high-pressure polyethylene homopolymer. The medium- and low-pressure ethylene homopolymer can be obtained by a conventionally known medium- and low-pressure ionic polymerization method. The high-pressure polyethylene homopolymer can be obtained by a conventionally known high-pressure radical polymerization method.

[0053] In the first adhesive resin layer 25, examples of the α-olefin used in the ethylene-α-olefin copolymer include propylene, 1-butene, 4-methyl-1-pentene, 3-methyl-1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene, 1-nonene, 1-decene, 1-undecene, and 1-dodecene, and one or more of these are used. The method for obtaining the ethylene-α-olefin copolymer is not particularly limited, and examples include high-, medium-, and low-pressure ionic polymerization methods using Ziegler-Natta catalysts, Phillips catalysts, and single-site catalysts. Such copolymers can be appropriately selected from commercially available products.

[0054] Examples of the epoxy group-containing compound contained in the adhesive resin constituting the first adhesive resin layer 25 include epoxidized vegetable oil (epoxidized unsaturated double bonds of natural vegetable oil), glycidyl ether type, glycidyl amine type, glycidyl ester type, etc. For example, epoxidized soybean oil, epoxidized linseed oil, epoxidized olive oil, epoxidized safflower oil, epoxidized corn oil, etc. are used. The content of such an epoxy group-containing compound is, for example, 0.01 to 10 parts by weight, preferably 0.01 to 5.0 parts by weight, relative to 100 parts by weight of the adhesive resin constituting the first adhesive resin layer 25.

[0055] A silane oligomer is preferably used as the silane group-containing compound contained in the adhesive resin constituting the first adhesive resin layer 25. More specifically, in order to increase adhesion, a silane oligomer containing any one of an epoxy group, a mercapto group, and an alkoxy group, or several of these groups in the molecule is preferable. The silane oligomer is mixed in an amount of 0.01 to 10 parts by weight, preferably 0.01 to 5 parts by weight, per 100 parts by weight of the adhesive resin constituting the first adhesive resin layer 25.

[0056] The carboxylic acid group-containing compound contained in the adhesive resin constituting the first adhesive resin layer 25 may be an ethylene-unsaturated carboxylic acid or a copolymer with an ester thereof. More specifically, an ethylene-acrylic acid copolymer, an ethylene-ethyl acrylate copolymer, an ethylene-methacrylic acid copolymer, or an ethylene-methyl methacrylate copolymer may be used. In addition, an ionomer resin in which ethylene-unsaturated carboxylic acid molecules are crosslinked with metal ions may be used.

[0057] As the acid anhydride-containing compound contained in the adhesive resin constituting the first adhesive resin layer 25, maleic acid-modified polyolefin resins such as maleic acid-modified polyethylene resins and maleic acid-modified polypropylene resins are preferred, and maleic anhydride-modified polyolefin resins such as maleic anhydride-modified polyethylene resins and maleic anhydride-modified polypropylene resins are more preferred. Note that the maleic acid-modified polyolefin resins are formed by graft polymerization of maleic acid to a polyolefin resin.

[0058] The thickness of the first adhesive resin layer 25 is preferably 10 μm or more and 50 μm or less, more preferably 10 μm or more and 30 μm or less, and further preferably 10 μm or more and 20 μm or less.

[0059] (First sealant layer) The first sealant layer 26 is located on the innermost side of the outer film 20. The first sealant layer 26 is in contact with the unsealed space SP and faces the second sealant layer 35 across the unsealed space SP. A part of the first sealant layer 26 is bonded to a part of the second sealant layer 35. Specifically, the outer edge of the first sealant layer 26 and the outer edge of the second sealant layer 35 are bonded to each other. A part of the first sealant layer 26 other than the outer edge is not bonded to the second sealant layer 35. An unsealed space SP is formed between a part of the first sealant layer 26 other than the outer edge and a part of the second sealant layer 35 other than the outer edge.

[0060] The first sealant layer 26 may be made of one or more of the following resins: polypropylene, low-density polyethylene (LDPE), medium-density polyethylene (MDPE), high-density polyethylene (HDPE), linear low-density polyethylene (LLDPE), ethylene-α-olefin copolymer polymerized using a metallocene catalyst, ethylene-propylene copolymer, ethylene-vinyl acetate copolymer, ionomer resin, ethylene-acrylic acid copolymer, ethylene-methyl acrylate copolymer, ethylene-methacrylic acid copolymer, etc. The thickness of the first sealant layer 26 may be 10 μm or more and 200 μm or less, 10 μm or more and 100 μm or less, or 20 μm or more and 80 μm or less.

[0061] (unsealed space) The unsealed space SP is located between the outer layer film 20 and the inner layer film 30. The unsealed space SP exists between a portion of the first sealant layer 26 that is not joined to the second sealant layer 35 and a portion of the second sealant layer 35 that is not joined to the first sealant layer 26. Air may be present in the unsealed space SP. The unsealed space SP may be an area where the outer layer film 20 and the inner layer film 30 are not joined. In the unsealed space SP, a part of the outer layer film 20 and a part of the inner layer film 30 may be in contact with each other.

[0062] (Second sealant layer) The second sealant layer 35 is located on the outermost side of the inner layer film 30. The second sealant layer 35 is in contact with the unsealed space SP and faces the first sealant layer 26 across the unsealed space SP. A portion of the second sealant layer 35 is joined to a portion of the first sealant layer 26.

[0063] The material of the second sealant layer 35 can be selected from the materials listed above as the materials of the first sealant layer 26. The material of the second sealant layer 35 may be the same as the material of the first sealant layer 26 or may be different from the material of the first sealant layer 26.

[0064] The thickness of the second sealant layer 35 may be 10 μm or more and 200 μm or less, 10 μm or more and 100 μm or less, or 20 μm or more and 80 μm or less.

[0065] (adhesive layer) The adhesive layer is located between the solvent permeation suppression layer 31 and the second sealant layer 35. The adhesive layer is a layer that bonds the solvent permeation suppression layer 31 and the second sealant layer .

[0066] The adhesive layer 36 can be formed by a conventional method, for example, a dry lamination method. When two layers are bonded by the dry lamination method, the adhesive layer 36 is formed by applying an adhesive to the surface of the layer to be laminated and drying it. The adhesive to be applied can be, for example, a one-component or two-component curing or non-curing type vinyl, (meth)acrylic, polyamide, polyester, polyether, polyurethane, epoxy, rubber, or other solvent-based, water-based, or emulsion-type adhesive. A two-component curing adhesive can be a cured product of a polyol and an isocyanate compound. The above-mentioned lamination adhesive can be applied by, for example, a direct gravure roll coating method, a gravure roll coating method, a kiss coating method, a reverse roll coating method, a Fountain method, a transfer roll coating method, or other methods.

[0067] The thickness of the adhesive layer 36 may be, for example, 1 μm or more and 5 μm or less.

[0068] (Solvent penetration inhibiting layer) As described above, the solvent penetration inhibiting layer 31 includes, in order from the inside, a second base material layer 32, a second vapor deposition layer 33, and a second barrier coat layer 34. The second base material layer 32 is directly laminated on the adhesive layer 36. The second vapor deposition layer 33 is directly laminated on the second base material layer 32. The second barrier coat layer 34 is directly laminated on the second vapor deposition layer 33.

[0069] (Second base material layer) The second base material layer 32 is a layer that inhibits the solvent filled in the liquid storage bag 10 from penetrating from the inside to the outside. The second base material layer 32 may be a layer that supports the second sealant layer 35, the third sealant layer 38, etc. and enhances the strength of the entire inner layer film 30. As the material constituting the second base material layer 32, for example, a film or sheet of a polyamide-based resin such as nylon or the like can be used.

[0070] In addition, as the film or sheet of the resin described above, an unstretched film may be used, or a stretched film stretched in one axial direction or two axial directions may be used.

[0071] The thickness of the second base material layer 32 may be, for example, 5 μm or more and 50 μm or less.

[0072] (Second vapor deposition layer) The second vapor deposition layer 33 is a layer for suppressing the permeation of solvents such as NMP. As the second vapor deposition layer 33, for example, a material having barrier properties against solvents or the like may be used. Specifically, as the second vapor deposition layer 33, for example, an aluminum foil, tin, lead, copper, iron, nickel, or an alloy thereof, or a thin metal vapor deposition layer of aluminum or the like may be used. When an aluminum foil is used as the second vapor deposition layer 33, the thickness of the second vapor deposition layer 33 may be 5 μm or more and 20 μm or less.

[0073] When a metal vapor-deposited layer of aluminum is used as the second vapor-deposited layer 33, the thickness of the second vapor-deposited layer 33 may be 50 Å or more and 3000 Å or less, and in particular, 100 Å or more and 2000 Å or less.

[0074] The second vapor deposition layer 33 may be a transparent vapor deposition layer that can be formed by a conventionally known method. In this case, the second vapor deposition layer 33 may be a transparent vapor deposition layer made of a vapor deposition layer of an inorganic oxide. In this way, the second vapor deposition layer 33 is a transparent vapor deposition layer, so that it is possible to impart or improve gas barrier properties that prevent the permeation of water vapor and the like while maintaining the permeability of the contents.

[0075] As the transparent deposition layer, for example, a deposition layer of an oxide of silicon (Si), aluminum (Al), magnesium (Mg), calcium (Ca), potassium (K), tin (Sn), sodium (Na), boron (B), titanium (Ti), lead (Pb), zirconium (Zr), yttrium (Y), etc. may be used.

[0076] (Second barrier coat layer) The second barrier coat layer 34 is a film that functions as a layer that suppresses the permeation of a solvent. The material of the second barrier coat layer 34 can be selected from the materials listed above as the materials of the first barrier coat layer 24. The material of the second barrier coat layer 34 may be the same as the material of the first barrier coat layer 24, or may be different from the material of the first barrier coat layer 24.

[0077] The thickness of the second barrier coating layer 34 may be, for example, not less than 10 Å and not more than 500 Å.

[0078] (Second adhesive resin layer) The second adhesive resin layer 37 is located between the solvent permeation suppression layer 31 and the third sealant layer 38. The second adhesive resin layer 37 is a layer that bonds the solvent permeation suppression layer 31 and the third sealant layer 38 together.

[0079] The second adhesive resin layer 37 can be made of a material selected from the materials listed above as the material for the first adhesive resin layer 25. The material for the second adhesive resin layer 37 may be the same as the material for the first adhesive resin layer 25, or may be different from the material for the first adhesive resin layer 25.

[0080] The thickness of the second adhesive resin layer 37 is preferably 10 μm or more and 50 μm or less, more preferably 10 μm or more and 30 μm or less, and further preferably 10 μm or more and 20 μm or less.

[0081] (Third sealant layer) The third sealant layer 38 is located on the innermost side of the inner layer film 30. The third sealant layer 38 faces the liquid LQ contained in the liquid storage bag 10. The third sealant layer 38 is a layer that directly contacts the liquid LQ. The third sealant layer 38 faces the third sealant layer 38 of the other inner layer film 30 via the liquid LQ (see FIG. 2). A part of the third sealant layer 38 is bonded to a part of the third sealant layer 38 of the other inner layer film 30. Specifically, the outer edge of the third sealant layer 38 and the outer edge of the third sealant layer 38 of the other inner layer film 30 are bonded to each other. The part of the third sealant layer 38 other than the outer edge is not bonded to the outer edge of the third sealant layer 38 of the other inner layer film 30. A space for storing the liquid LQ is formed between the part of the third sealant layer 38 other than the outer edge and the part of the third sealant layer 38 of the other inner layer film 30 other than the outer edge.

[0082] The material of the third sealant layer 38 can be selected from the materials listed above for the first sealant layer 26. The material of the third sealant layer 38 can be the same as the material of the first sealant layer 26 or can be different from the material of the first sealant layer 26. The material of the third sealant layer 38 can be the same as the material of the second sealant layer 35 or can be different from the material of the second sealant layer 35.

[0083] The thickness of the third sealant layer 38 may be 10 μm or more and 200 μm or less, 10 μm or more and 100 μm or less, or 20 μm or more and 80 μm or less.

[0084] [Method of manufacturing liquid storage bag] Next, a method for manufacturing the liquid storage bag 10 according to the present embodiment will be described with reference to Figures 4(a)-(c) and 5(a)-(d). Figures 4(a)-(c) and 5(a)-(d) are cross-sectional views showing the method for manufacturing the liquid storage bag 10.

[0085] First, as shown in Figs. 4(a)-(c), an inner layer film 30 is prepared.

[0086] In this case, first, a solvent permeation suppression layer 31 is produced as shown in Fig. 4(a). At this time, for example, a second vapor deposition layer 33 is formed on a second base layer 32 by a vapor deposition method. Then, a second barrier coat layer 34 is formed on the second vapor deposition layer 33. The second barrier coat layer 34 can be applied by, for example, a direct gravure roll coating method, a gravure roll coating method, a kiss coating method, a reverse roll coating method, a Fontaine method, a transfer roll coating method, or other methods.

[0087] 4(b), the solvent permeation suppression layer 31 and the second sealant layer 35 are joined to each other via the adhesive layer 36. In this case, the solvent permeation suppression layer 31 and the second sealant layer 35 may be attached to each other via the adhesive layer 36 by, for example, a dry lamination method.

[0088] Next, as shown in Fig. 4(c), the solvent permeation suppression layer 31 and the third sealant layer 38 are bonded via the second adhesive resin layer 37. In this case, the solvent permeation suppression layer 31 and the second sealant layer 35 may be bonded together by a melt extrusion lamination method using the second adhesive resin layer 37. In this manner, the inner layer film 30 is obtained as shown in Fig. 4(c).

[0089] Furthermore, as shown in Figs. 5(a) and (b), an outer film 20 is prepared.

[0090] In this case, first, a water vapor barrier layer 21 is produced as shown in Fig. 5(a). In this case, for example, a first deposition layer 23 is formed on a first base layer 22 by a deposition method. Then, a first barrier coat layer 24 is formed on the first deposition layer 23. The first barrier coat layer 24 can be applied by, for example, a direct gravure roll coating method, a gravure roll coating method, a kiss coating method, a reverse roll coating method, a Fontaine method, a transfer roll coating method, or other methods.

[0091] Next, as shown in Fig. 5(b), the water vapor barrier layer 21 and the first sealant layer 26 are bonded via the first adhesive resin layer 25. In this case, the water vapor barrier layer 21 and the first sealant layer 26 may be bonded together by a melt extrusion lamination method using the first adhesive resin layer 25. In this manner, the outer layer film 20 is obtained, as shown in Fig. 5(b).

[0092] The order in which the inner layer film 30 and the outer layer film 20 are produced does not matter.

[0093] Next, as shown in Figure 5 (c), a pair of inner layer films 30, 30 and a pair of outer layer films 20, 20 are prepared. Next, the pair of inner layer films 30, 30 are placed between the pair of outer layer films 20, 20. In this case, for example, the pair of outer layer films 20, 20 and the pair of inner layer films 30, 30 wound in a roll shape are continuously unwound. Next, the pair of outer layer films 20, 20 are overlapped so that the pair of inner layer films 30, 30 are placed between them.

[0094] 5(d), the pair of outer layer films 20, 20 and the pair of inner layer films 30, 30 are heat-sealed at positions corresponding to the three side edges 15 of the liquid storage bag 10. As a result, a part of the pair of outer layer films 20, 20 and a part of the pair of inner layer films 30, 30 are heat-sealed to each other. At this time, a space for storing the liquid LQ containing a solvent is formed between the pair of inner layer films 30, 30. In addition, an unsealed space SP is formed between each outer layer film 20 and each inner layer film 30.

[0095] Thereafter, the pair of outer layer films 20, 20 and the pair of inner layer films 30, 30 that are heat-sealed at the side edge portions 15 are cut into individual pieces in the shape of the liquid storage bag 10. In this manner, the liquid storage bag 10 is obtained as shown in Fig. 5(d).

[0096] Next, the liquid storage bag 10 is placed in a container body 51 to obtain a transport container 50 (see FIG. 1). Next, liquid LQ is accommodated in the liquid storage bag 10 as the content. The liquid LQ may contain a solvent such as N-methyl-2-pyrrolidone (hereinafter also referred to as NMP). The liquid LQ may also be, for example, a slurry used in producing lithium ion batteries. The transport container 50 in which the liquid storage bag 10 accommodates the liquid LQ containing the solvent is stored or transported.

[0097] During storage or transportation in this manner, there is a possibility that the solvent contained in the liquid LQ will permeate between the layers of the liquid storage bag 10. If the solvent permeates between the layers of the liquid storage bag 10, the amount of the solvent in the liquid LQ will decrease. This may result in a change in the concentration of a component (e.g., carbon black) in the liquid LQ.

[0098] In contrast, according to this embodiment, the inner layer film 30 has a solvent permeation suppression layer 31, and an unsealed space SP is formed between the outer layer film 20 and the inner layer film 30. Therefore, as shown in Fig. 3, even if the solvent SV contained in the liquid LQ permeates through the third sealant layer 38, it is blocked by the solvent permeation suppression layer 31 and is prevented from permeating into the second sealant layer 35. Furthermore, even if a portion of the solvent SV contained in the liquid LQ permeates the solvent permeation suppression layer 31, the presence of the unsealed space SP prevents the solvent SV from reaching the outer layer film 20.

[0099] During storage in this manner, the solvent SV contained in the liquid LQ and the moisture WT in the external atmosphere may react between the layers constituting the liquid storage bag 10. If the solvent SV and the moisture WT react between the layers of the liquid storage bag 10, blisters may form between the layers, and delamination may occur.

[0100] In contrast, according to the present embodiment, the outer layer film 20 has a water vapor barrier layer 21, and an unsealed space SP is formed between the outer layer film 20 and the inner layer film 30. As a result, as shown in FIG. 3, the moisture WT in the atmosphere outside the liquid storage bag 10 is blocked by the water vapor barrier layer 21, and is prevented from penetrating to the first sealant layer 26 side. Even if a portion of the moisture WT in the atmosphere permeates the water vapor barrier layer 21, the presence of the unsealed space SP prevents the moisture WT from reaching the inner layer film 30 side. As a result, the solvent SV contained in the liquid LQ and the moisture WT in the atmosphere are prevented from reacting with each of the layers constituting the liquid storage bag 10, and the generation of blisters and delamination between the layers can be prevented.

[0101] [Example] Next, a specific example of this embodiment will be described.

[0102] Example 1 A liquid storage bag having an outer layer film and an inner layer film as shown in FIG. 2 was produced.

[0103] The outer layer film has a water vapor barrier layer, a first adhesive resin layer, and a first sealant layer. The water vapor barrier layer was a gas barrier film (manufactured by Dai Nippon Printing Co., Ltd., product: IB-Ny-UB, thickness 15 μm) from the outside. The deposition surface side of the barrier film was coated with a two-component curing polyurethane adhesive (A-3210 / A-3075, manufactured by Mitsui Chemicals, Inc.) to a thickness of 0.3 μm, and then a low-density polyethylene resin (density 0.918 g / cm 3A 15 μm thick PEF (additive-free LLDPE, manufactured by Tamapoly Co., Ltd., product name: SK-615P) was sandwiched between a 15 μm thick PEF film (additive-free LLDPE, manufactured by Tamapoly Co., Ltd., product name: SK-615P) and a laminate was obtained as an outer layer film.

[0104] The inner layer film has a third sealant layer, a second adhesive resin layer, a solvent permeation suppression layer, an adhesive layer, and a second sealant layer. A barrier nylon film (hereinafter also referred to as barrier Ny) was used as the solvent permeation suppression layer. The solvent permeation suppression layer includes, from the inside, a second base layer, a second vapor deposition layer, and a second barrier coat layer. A gas barrier film (manufactured by Dai Nippon Printing Co., Ltd., product: IB-Ny-UB, thickness 15 μm) was used as the second base layer. PEF (additive-free LLDPE, manufactured by Tamapoly Co., Ltd., product name: SK-615P, thickness 70 μm) was used as the third sealant layer and the second sealant layer. A two-component curing adhesive (manufactured by Rock Paint Co., Ltd., base agent: RU-004, curing agent: H-1) was used as the adhesive layer. A low-density polyethylene resin (density 0.918 g / cm 3 , MFR: 7.0 g / 10 min, melting point: 106° C., company name: Japan Polyethylene Co., Ltd., product name: Novatec LC600A) was used.

[0105] In summary, the layer structure of the liquid storage bag is expressed as follows, from the outside: (Outer) Barrier Ny / EC / PEF / / PEF / DL / Barrier Ny / EC / PEF (Inner)

[0106] Here, " / " indicates the boundary between layers (as below). "Barrier Ny" means barrier nylon film (as below). "EC" means adhesive resin layer which is an extrusion laminate layer (as below). " " (space) means empty space (as below). "PEF" means polyolefin film (as below). "DL" means adhesive layer (as below).

[0107] Next, two outer layer films and two inner layer films were cut into a size of 150 mm x 200 mm. Two inner layer films were overlapped between two outer layer films, and three edges were attached with a heat seal bar with a width of about 10 mm. Next, 500 ml of N-methyl-2-pyrrolidone (NMP) as a solvent was filled into the opening between the two inner layer films. Then, the two outer layer films and the two inner layer films located at the above-mentioned opening were sealed by heat sealing to obtain a sample of Example 1. Then, the sample of Example 1 was left at 60 ° C for two weeks, and the presence or absence of delamination, the surface condition, and the weight change were confirmed. In addition, before and after leaving the sample at 60 ° C for two weeks, NMP was taken out of the liquid storage bag, and the seal strength of the attached heat seal part was measured based on JIS Z 1711.

[0108] Comparative Example 1 A liquid storage bag was produced in the same manner as in Example 1, except that it had the following layer structure from the outside: (Outer) Barrier Ny / EC / PEF / / PEF / / PEF / / PEF (inner) Thereafter, in the same manner as in Example 1, the presence or absence of delamination, the surface condition, and the change in weight were confirmed, and the seal strength was measured.

[0109] Comparative Example 2 A liquid storage bag was produced in the same manner as in Example 1, except that it had the following layer structure from the outside: (Outer) PEF / / PEF / DL / Barrier Ny / EC / PEF (Inner) Thereafter, in the same manner as in Example 1, the presence or absence of delamination, the surface condition, and the change in weight were confirmed, and the seal strength was measured.

[0110] Comparative Example 3 A liquid storage bag was produced in the same manner as in Example 1, except that it had the following layer structure from the outside: (Outside)Ny / EC / PEF / / PEF / / PEF / / PEF(Inside) Thereafter, the presence or absence of delamination, the surface condition, and the change in weight were confirmed, and the seal strength was measured in the same manner as in Example 1. Here, "Ny" means a single-layer nylon film.

[0111] The results are shown in Table 1 below.

[0112] [Table 1]

[0113] In the above table, "Delamination" indicates the result of visually judging whether or not blisters have occurred between the layers of the liquid storage bag. "Surface condition" indicates the result of visually judging whether or not NMP has seeped out to the outermost surface of the liquid storage bag. "Weight change" indicates the result of measuring the percentage (%) by which the weight of NMP in the liquid storage bag has decreased after being left undisturbed for two weeks, with the weight before being set at 100% as the reference (100%). "Seal strength" indicates the result of measuring the percentage (%) by which the seal strength (N) of the liquid storage bag has decreased after being left undisturbed for two weeks, with the weight before being set at 100% as the reference (100%), as described above, based on JIS Z 1711.

[0114] As shown in Table 1, the liquid storage bag according to Example 1 obtained good results (no blisters, no seepage) in both delamination and surface condition. Furthermore, the liquid storage bag according to Example 1 showed the smallest change in weight of NMP before and after leaving the bag for two weeks, and also showed the smallest decrease in seal strength, compared to the liquid storage bag according to Comparative Example 1-3.

[0115] It is also possible to combine the multiple components disclosed in each of the above embodiments and modifications as necessary. Alternatively, some components may be deleted from all the components shown in each of the above embodiments and modifications. [Explanation of symbols]

[0116] 10 Liquid storage bag 20 Outer film 21 Water Vapor Barrier Layer 22 1st base layer 23 1st vapor deposition layer 24 First barrier coat layer 25 First adhesive resin layer 26 First sealant layer 30 Inner layer film 31 Solvent penetration prevention layer 32 Second base layer 33 Second vapor deposition layer 34 Second barrier coat layer 35 Second sealant layer 36 Adhesive layer 37 Second adhesive resin layer 38 3rd sealant layer 50 Shipping containers 50A Liquid transport container 51 Container body

Claims

1. A liquid storage bag, An outer layer film; An inner layer film located inside the outer layer film, The outer layer film has a water vapor barrier layer and a first sealant layer located on an inner side of the water vapor barrier layer, the inner layer film has a solvent permeation suppression layer, a second sealant layer located on the outer side of the solvent permeation suppression layer, and a third sealant layer located on the inner side of the solvent permeation suppression layer, a portion of the first sealant layer and a portion of the second sealant layer are joined to each other; The liquid storage bag has an unsealed space formed between the outer layer film and the inner layer film.

2. A pair of the outer layer films and a pair of the inner layer films, The pair of inner layer films are overlapped with each other, 2. The liquid storage bag according to claim 1, wherein a portion of the third sealant layer of one of the inner layer films and a portion of the third sealant layer of the other of the inner layer films are joined to each other.

3. The liquid storage bag according to claim 1 , wherein the water vapor barrier layer includes, in order from the outside, a first substrate layer, a first deposition layer, and a first barrier coat layer.

4. The liquid storage bag according to claim 1 , wherein the solvent permeation prevention layer includes, from the inside, a second base material layer, a second vapor deposition layer, and a second barrier coat layer.

5. The liquid storage bag according to claim 1 , wherein the water vapor barrier layer and the first sealant layer are bonded to each other by a first adhesive resin layer.

6. 2. The liquid storage bag according to claim 1, wherein the solvent permeation suppression layer and the second sealant layer are bonded to each other by an adhesive layer.

7. 2. The liquid storage bag according to claim 1, wherein the solvent permeation suppression layer and the third sealant layer are bonded to each other by a second adhesive resin layer.

8. A container body; A transport container comprising: the liquid storage bag according to claim 1 housed in the container body.

9. A transport container according to claim 8; A liquid contained in the liquid storage bag of the transport container, A liquid-containing transport container, wherein the liquid comprises a solvent.

10. 10. The liquid-containing transport container according to claim 9, wherein the solvent is N-methyl-2-pyrrolidone.

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