JP2004074419A - Laminate and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a laminate excellent in hermetic sealability, having high lamination strength, low in moisture permeability as a package of a lithium battery and especially excellent in electrolyte resistance, and its manufacturing method. <P>SOLUTION: In the laminate comprising an outer layer, an aluminum foil and an inner layer and having a chemical conversion layer at least provided to the surface of the aluminum foil on the side of the inner layer, the resin layer being contact with the chemical conversion layer of the inner layer comprises an acid modified olefin resin. The laminate is obtained by laminating the surface of the chemical conversion layer, the single layer film of the acid modified olefin resin or a coextrusion film of the acid modified olefin resin and one or more olefin resins by a thermal lamination method. <P>COPYRIGHT: (C)2004,JPO

Description

※）ラミネート強度：
アルミニウム箔の化成処理層と内層間の接着強度をテンシロンを用いて、５０ｍｍ／分の引張り速度で測定した。尚、測定値は２０サンプルの平均値である。
※）耐電解液性：
３ｇの電解液〔６フッ化リン酸リチウムを混合液〔エチレンカーボネート／ジエチルカーボネート／ジメチルカーボネート＝１／１／１（容積比）に溶解し、１モル／リットルの６フッ化リン酸リチウム溶液としたもの〕を充填した内寸が３０×５０ｍｍでヒートシール幅が７ｍｍの三方シール袋を８５℃の恒温槽に３３６時間保存した後のアルミニウム箔の化成処理層と内層間の接着強度をテンシロンを用いて、５０ｍｍ／分の引張り速度で測定した。尚、測定値は２０サンプルの平均値である。
※）水分透過量：
３ｇの混合液〔エチレンカーボネート／ジエチルカーボネート／ジメチルカーボネート＝１／１／１（容積比）〕を充填した内寸が３０×５０ｍｍでヒートシール幅が７ｍｍの三方シール袋を６０℃、９０％ＲＨの恒温恒湿槽に１４４０時間保存し、水分増加量をカールフィッシャー法で測定した。なお、測定値は５サンプルの平均値である。
【００４３】
表１からも明らかなように、実施例１〜６の積層体は比較例１に比べて、特に耐電解液に対して耐性を有し、ラミネート強度の低下の極めて少ない積層体とすることができた。
【００４４】
【発明の効果】
以上縷々説明したように、本発明の積層体は、密封性に優れると共にラミネート強度が強く、リチウム電池の包装体としたときに水分透過量が少なく、特に耐電解液性に優れるという極めて顕著な効果を奏するものである。また、本発明の積層体の製造方法は、上記した顕著な効果を奏する積層体を生産効率よく製造することができる。
【図面の簡単な説明】
【図１】本発明にかかる積層体の一実施例の層構成を図解的に示す図である。
【図２】リチウム電池に用いる包装体の一実施例を説明する図である。
【図３】リチウム電池に用いる包装体の他の実施例を説明する図である。
【符号の説明】
１、１’　　　　　　　　　　　積層体
１０　　　　　　　　　　　　　外層
２０　　　　　　　　　　　　　化成処理層
３０　　　　　　　　　　　　　アルミニウム箔
４０　　　　　　　　　　　　　接着層
５０　　　　　　　　　　　　　内層[0001]
TECHNICAL FIELD OF THE INVENTION
TECHNICAL FIELD The present invention relates to a laminate having excellent sealing properties, moisture-proof properties, and content resistance, which is used as an outer package of a secondary battery, particularly a lithium battery having an electrolyte (liquid or solid electrolyte), and a method for producing the same.
[0002]
[Prior art]
A lithium battery is also called a lithium secondary battery. It is a battery that consists of a solid polymer, gel polymer, liquid, etc. as an electrolyte, and generates electricity by the movement of lithium ions. Including those consisting of The configuration of the lithium secondary battery includes a positive electrode current collector (aluminum, nickel) / a positive electrode active material layer (a metal positive electrode material such as a metal oxide, carbon black, a metal sulfide, an electrolytic solution, and polyacrylonitrile) / an electrolyte (propylene carbonate). , Carbonate-based electrolytes such as ethylene carbonate, dimethyl carbonate and ethylene methyl carbonate, inorganic solid electrolytes composed of lithium salts, gel electrolytes) / negative electrode active material layer (lithium metal, alloy, carbon, electrolytes, polymers such as polyacrylonitrile) It comprises a lithium battery main body composed of a negative electrode material) / a negative electrode current collector (copper, nickel, stainless steel) and an outer package for packaging them. Lithium ion secondary batteries are widely used in electronic devices and electronic components, particularly mobile phones, notebook computers, video cameras, etc. due to their high volume efficiency and weight efficiency.
[0003]
As the exterior body of the lithium battery, a metal can or a metal foil or the like is press-formed, and a metal can having a columnar or rectangular parallelepiped shape is generally used from the viewpoint of productivity and stability of quality. When a metal can is used, there are many restrictions on the shape and design of the battery itself, and in addition, the shape and design of the battery housing portion in an electronic device or electronic component on which the battery made of the metal can is mounted There is also a problem in that the performance of the electronic device and the electronic component itself cannot be changed to an intended shape, which has been an obstacle to further downsizing and weight reduction of the electronic device and the electronic component. On the other hand, a battery made of a metal can has a problem that when the battery is used at a high temperature and the internal pressure is abnormally increased, the outer body is durable until an explosion or ignition occurs. .
[0004]
Therefore, in order to have flexibility, the shape can be adjusted to an appropriate space of the electronic device or electronic component, and the shape of the electronic device or electronic component itself can be freely designed to some extent. If the battery is used at a high temperature and the internal pressure rises abnormally because the battery is sealed with a thermal bonding part, the thermal bonding part peels off the internal pressure and releases the internal pressure. Although it loses its function as a battery because it functions as a battery, it is possible to reduce the danger of explosion and fire compared to an exterior body made of metal cans. For example, using the laminated body having a configuration as described below, the laminated body is formed into a bag and formed into a bag shape at the peripheral heat bonding portion as shown in FIG. 2 (a). Type, but may be a three-sided or four-sided type, etc.], and protrude outward the metal terminals connected to the positive and negative electrodes of the lithium battery body (not shown). 2 (b) or the laminate is press-molded as shown in FIG. 3 (a) to form a recess. A metal terminal connected to each of the positive electrode and the negative electrode of the lithium battery body (not shown) is housed in the recess in a state of protruding outward, and the sheet-shaped laminate (not shown) separately prepared is provided. A lithium battery comprising an embossed type exterior body (hereinafter, referred to as a package) shown in FIG. 3B, which covers the recess and seals the periphery by heat bonding, has been used. Was. In addition, the code | symbol 1 'shown on FIGS. 2 and 3 is a laminated body, the code | symbol D is a lithium battery, the code | symbol S shows a heat bonding part, and T shows a metal terminal.
[0005]
The package has physical properties required for a lithium battery, namely, moisture proof, sealing, puncture resistance, insulation, heat and cold resistance, electrolyte resistance (electrolyte resistance), corrosion resistance (electrolyte resistance). Resistance to hydrofluoric acid generated by deterioration or hydrolysis) is required as an indispensable element. As a result, the package has an outer layer for preventing piercing resistance and preventing electricity from flowing to the outside, a barrier layer made of a metal foil such as aluminum for securing moisture resistance, and an inner layer for securing sealing. The configured laminate is generally used. If the adhesion strength between the layers is not sufficient (hereinafter, referred to as lamination strength), for example, if the lamination strength between the barrier layer and the inner layer is not sufficient, moisture may enter from the outside and the electrolyte constituting the lithium battery Reacts with the infiltrated water to generate hydrogen fluoride, which corrodes the barrier layer and easily causes delamination between the barrier layer and the inner layer. If the laminate strength with the barrier layer is not sufficient, there is a problem in the above-mentioned embossed type package that delamination may occur between the outer layer and the barrier layer during embossing.
[0006]
In view of this, the present applicant discloses in JP-A-2001-176462 that a chemical conversion treatment layer formed by phosphoric acid chromate treatment is formed on both surfaces of a barrier layer made of a metal foil such as aluminum, and a surface on the inner layer side of the chemical conversion treatment layer. An acid-modified polypropylene resin emulsion is applied and dried using a method such as a roll coating method, and heated (baked) at a temperature of 170 to 200 ° C. to obtain a solid content of 2 to 5 g / m 2. ² A laminated body (packaging material for polymer batteries) in which an acid-modified polypropylene resin film is formed and the inner layer of the acid-modified polypropylene resin film and the inner layer made of the cast polypropylene film are bonded by a thermal lamination method is proposed. A laminate (packaging material for a polymer battery) having a higher laminate strength between the barrier layer and the inner layer and a smaller amount of moisture permeation than the specification was able to be obtained.
[0007]
However, the formation of the acid-modified polypropylene resin film takes a long time to bake and the production efficiency is poor.Although a certain result has been obtained with respect to the resistance to the electrolytic solution, the resistance is not sufficiently satisfied. Was not reached, and we decided to make further improvements.
[0008]
[Problems to be solved by the invention]
Accordingly, an object of the present invention is to provide a laminate having excellent sealing properties, high lamination strength, a small amount of water permeation when used as a lithium battery package, and particularly having excellent electrolytic solution resistance, and a method for producing the same. .
[0009]
[Means for Solving the Problems]
In order to achieve the above object, the present invention provides a laminate comprising an outer layer, an aluminum foil, and an inner layer, wherein at least a chemical conversion treatment layer is provided on the inner layer side of the aluminum foil. In, the resin layer in contact with the surface of the chemical conversion treatment layer of the inner layer is made of an acid-modified olefin resin and a single-layer film of the chemical conversion treatment surface and the acid-modified olefin resin or the acid-modified olefin resin and one or more olefin resins The co-extruded film is bonded by a thermal lamination method.
[0010]
According to a second aspect of the present invention, in the laminate according to the first aspect, the inner layer is a single-layer film made of an ethylene resin graft-modified with an unsaturated carboxylic acid.
[0011]
According to a third aspect of the present invention, in the laminate of the first aspect, the inner layer is a single-layer film made of a propylene resin graft-modified with an unsaturated carboxylic acid.
[0012]
According to a fourth aspect of the present invention, in the first aspect of the present invention, the inner layer is a co-extruded film comprising an ethylene resin graft-modified with an unsaturated carboxylic acid and one or more ethylene resins. It is a feature.
[0013]
According to a fifth aspect of the present invention, in the first aspect of the present invention, the inner layer is a co-extruded film comprising a propylene resin layer graft-modified with an unsaturated carboxylic acid and one or more propylene resin layers. It is characterized by having.
[0014]
According to a sixth aspect of the present invention, there is provided the laminate according to any one of the fourth and fifth aspects, wherein the ethylene resin or the propylene resin graft-modified with the unsaturated carboxylic acid of the co-extruded film has at least 5 μm. It is characterized by being a thickness.
[0015]
According to a seventh aspect of the present invention, in the laminate according to any one of the first to sixth aspects, the inner layer has a thickness of 25 μm or more.
[0016]
By adopting the constitution described in any one of the first to seventh aspects, it is possible to obtain a laminate having a high lamination strength, a small amount of water permeation, and particularly excellent in electrolytic solution resistance. In addition, by adopting the constitution of the above-mentioned claim 6, since it is possible to obtain sufficient strength in heat bonding strength (heat sealing strength) when the package is formed, ethylene modified with unsaturated carboxylic acid is used. The amount of the resin or the propylene resin used can be reduced, and a less expensive laminate can be obtained. In addition, by adopting the configuration described in claim 7, when the inner layer is heat-bonded (heat-sealed) to each other using the laminate to form a package, there is no leakage of the content from the heat-bonded portion. Further, sufficient heat sealing strength can be obtained such that the bag is not broken even if the internal pressure is increased by the gas generated from the contents. Usually, the heat seal strength is sufficient if the heat seal strength is 15 N width and 30 N or more. However, if the thickness of the inner layer is less than 25 μm, the heat seal strength may not be obtained, and the breakage due to leakage of contents or increase in internal pressure may occur. There is a risk of occurrence of bags.
[0017]
According to an eighth aspect of the present invention, in the laminate of the first aspect, a chemical conversion treatment layer is provided on a surface on the outer layer side of the aluminum foil. With this configuration, it is possible to prevent the occurrence of delamination between the outer layer and the aluminum foil during press working even in an embossed package.
[0018]
The method for producing a laminate of the present invention according to claim 9 includes a step of laminating the outer layer and the other surface of the aluminum foil provided with the chemical conversion treatment layer on at least one surface; A layer film or an inner layer made of a co-extruded film of the acid-modified olefin resin and one or more olefin resins is heated so that the chemical conversion treatment layer has a temperature not lower than the softening point of the acid-modified olefin resin and not higher than the melting point. Bonding the acid-modified olefin resin to the chemical conversion treatment layer by a thermal lamination method to form an intermediate laminate, and heating the intermediate laminate to a temperature equal to or higher than the melting point of the acid-modified olefin resin. And a step of performing By adopting such a method for manufacturing a laminate, a laminate having a small amount of water permeation and having satisfactory resistance to electrolyte resistance can be produced with high production efficiency.
[0019]
BEST MODE FOR CARRYING OUT THE INVENTION
The present invention will be described in detail below with reference to the drawings and the like.
FIG. 1 is a diagram schematically illustrating a layer configuration of an embodiment of a laminate according to the present invention, FIG. 2 is a diagram illustrating an embodiment of a package used for a lithium battery, and FIG. 3 is a package used for a lithium battery. FIG. 3 is a view for explaining another embodiment of the present invention, wherein 1 and 1 ′ in the figure indicate a laminate, 10 indicates an outer layer, 20 indicates a chemical conversion treatment layer, 30 indicates an aluminum foil, 40 indicates an adhesive layer, and 50 indicates an inner layer.
[0020]
FIG. 1 is a diagram schematically illustrating a layer configuration of an embodiment of a laminate according to the present invention. The laminate 1 has an outer layer 10 and a chemical conversion treatment layer 20 on one surface of an aluminum foil 30 on both surfaces. Is bonded via an adhesive layer 40, and on the other surface of the aluminum foil 30, a resin layer in contact with the chemical conversion treatment layer 20 is made of an acid-modified olefin resin, and the surface of the chemical conversion treatment layer and the acid-modified olefin resin The inner layer 50 composed of a single-layer film or a co-extruded film of the acid-modified olefin resin and one or more olefin resins is bonded by a thermal lamination method.
[0021]
First, the outer layer 10 will be described. The outer layer 10 is provided for the purpose of protecting the aluminum foil 30, particularly improving the resistance to external force such as piercing, and preventing the aluminum foil 30 from being perforated or broken. Although it may be a layer and may be a multilayer, it is necessary to attain the above-mentioned object by itself in the case of a single layer in particular, and it has excellent mechanical strength and at least a heat bonding temperature at the time of forming a package ( Dimensional stability with respect to heat sealing temperature) is required, and considering these, polyester films such as polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polybutylene naphthalate, polycarbonate, etc. For example, polyamide fibers such as nylon 6, nylon 66, etc. Beam but are suitable, when the laminate of the present invention the package of the embossing type, large biaxially stretched polyamide film is preferably stretched in comparison with the biaxially oriented polyester film. When the outer layer 10 is formed as a single layer as described above, it is appropriate that the thickness is at least 6 μm or more. The reason for this is that if the thickness is less than 6 μm, there is a possibility that pinholes may be present in itself and the effect of protecting the aluminum foil 30 against external force is reduced. This is because pinholes and breaks are likely to occur in the aluminum foil 30 and molding defects are likely to occur, and the thickness is more preferably 12 μm or more. Further, when the outer layer 10 is a single layer or a multi-layer, if it is thicker than 25 μm, a remarkable effect is not recognized in protection of the aluminum foil 30 against external force, and the volume and the weight energy density are reduced and the cost is reduced. It is desirable not to use it from the viewpoint of effect.
[0022]
Further, in the case of an embossed package, uniform press molding without thickness unevenness (thickness variation) by preventing the laminate 1 from partially adhering to a mold during press molding. For the purpose of obtaining a product (for the purpose of improving the formability at the time of press molding), the surface of the outer layer 10 may be, for example, a hydrocarbon system such as liquid paraffin, a fatty acid system such as stearic acid, a fatty acid amide system such as stearylamide, metal A lubricant such as soap, natural wax, silicone or the like is made into a coatable state by, for example, dissolving it in a suitable solvent, and for example, a gravure coating method, a roll coating method, or a gravure printing method when forming in a pattern form May be used to form the lubricant layer.
[0023]
Next, the aluminum foil 30 will be described. The aluminum foil 30 is provided in order to prevent water vapor from particularly entering the inside of the battery from the outside, and has a thickness of 20 to 80 μm in consideration of securing water vapor barrier properties and workability during processing. What is appropriate is. When the thickness is less than 20 μm, the pinhole of the aluminum foil alone is feared, and the danger of water vapor infiltration increases. When the thickness is more than 80 μm, no significant effect is recognized on the pinhole of the aluminum foil. Further, further improvement in the water vapor barrier property cannot be expected, and conversely, it is desirable not to use it from the viewpoint of reducing the volume and the weight energy density and from the viewpoint of cost-effectiveness.
[0024]
Further, the aluminum foil 30 containing 0.3 to 9.0% by weight, preferably 0.7 to 2.0% by weight of iron has excellent extensibility as compared with the one containing no iron, and also has good resistance to bending. Since pinholes are less likely to occur and a uniform molded product without uneven thickness can be obtained particularly during press molding, it is suitable for embossed type packages. When the iron content is less than 0.3% by weight, no effect is observed in the prevention of pinhole generation and spreadability, and when the iron content is more than 9.0% by weight, flexibility as aluminum foil is impaired. The suitability for bag making during the bag making process is reduced.
[0025]
Although the aluminum foil 30 is manufactured by cold rolling, its flexibility, stiffness, and hardness change under annealing (so-called annealing) conditions, but the aluminum foil used in the present invention is annealed. It is preferable to use an aluminum foil which is slightly or completely annealed and has a tendency to be softer than an unhardened product. The annealing conditions of the aluminum foil that determine the flexibility, the strength of the waist, and the hardness may be appropriately determined depending on the type of the package (bag type or emboss type).
[0026]
Next, the chemical conversion treatment layer 20 provided on both surfaces of the aluminum foil 30 will be described. The chemical conversion treatment layer 20 firmly adheres the aluminum foil 30 to the outer layer 10 and the inner layer 50 to prevent delamination at the time of press molding, and also performs electrolysis on the surface of the aluminum foil 30 on the inner layer 50 side. It is provided to protect the solution or hydrofluoric acid generated by hydrolysis of the electrolytic solution. The chemical conversion treatment layer 20 is formed of a chromium-based chemical treatment such as chromate chromate treatment, phosphoric acid chromate treatment, or coating-type chromate treatment, or a non-chromium-based (coating-type) chemical treatment such as zirconium, titanium, or zinc phosphate. It is formed on the surface of the aluminum foil 30 by the above method. Among the above-mentioned chemical conversion treatments, a coating-type chemical conversion treatment is most preferable in that a continuous treatment is possible, a washing step is unnecessary, and the treatment cost can be reduced. This coating-type chemical conversion treatment includes, for example, a chromium-based aqueous treatment liquid comprising a water-soluble polymer such as phenol or polyacrylic acid, a trivalent chromium compound, a fluoride and phosphoric acid, or an aqueous solution of phenol or polyacrylic acid. This is a process in which a non-chromium-based aqueous treatment liquid comprising a conductive polymer and a zirconium salt is applied to an aluminum foil surface by a known coating method such as a roll coating method, a gravure coating method, and a dipping method, and then dried. The drying is performed under the condition that the surface temperature of the aluminum foil 30 reaches 170 to 200 ° C. or more to form a film. Before the coating chemical conversion treatment, the surface of the aluminum foil on which the coating chemical conversion treatment is to be performed in advance is, for example, an alkali immersion method, an electrolytic cleaning method, an acid cleaning method, an electrolytic acid cleaning method, an acid activation method, or the like. It is preferable to perform the treatment by a well-known degreasing method from the viewpoint that the function of the coating type chemical conversion treatment is maximized and the treatment can be maintained for a long time. Note that the chemical conversion treatment layer 20 provided on the outer layer 10 side of the aluminum foil 30 may not be provided in the case of a bag-type package.
[0027]
Next, the inner layer 50 will be described. The inner layer 50 may be a single layer or multiple layers. In short, the inner layer 50 may be any resin layer in contact with the chemical conversion treatment layer 20 as long as it is an olefin resin film made of an acid-modified olefin resin. The reason for this is that, in order to firmly bond the chemical conversion treatment layer 20 and the inner layer 50, the laminate of the present invention bonds the outer layer 10 and the aluminum foil 30 via the adhesive layer 40, Thereafter, an appropriate heat treatment method such that the chemical conversion treatment layer 20 has a temperature of not less than the softening point of the acid-modified olefin resin and not more than the melting point, for example, 1 to 2 such as hot roll contact type, hot air type, near to far infrared ray, etc. Heated by the above heat treatment method, the chemical conversion treatment layer 20 and the inner layer 50 are bonded by a thermal lamination method to form an intermediate laminate, and then the intermediate laminate is subjected to an appropriate heat treatment method as described above. This is because a two-step heat treatment method of reheating so as to have a temperature equal to or higher than the melting point of the acid-modified olefin resin is employed.
[0028]
Examples of the acid-modified olefin resin constituting the inner layer 50 include an olefin resin graft-modified with an unsaturated carboxylic acid, a copolymer of ethylene or propylene with acrylic acid, or methacrylic acid, or a metal cross-linked polyolefin resin. Although it can be used, an olefin resin graft-modified with an unsaturated carboxylic acid is more preferred. The reason for this is that olefin resins graft-modified with unsaturated carboxylic acids have better heat resistance than acid-modified polyolefins such as copolymers of ethylene or propylene with acrylic acid or methacrylic acid. The inner layer 50 may be a film made of the acid-modified olefin resin single layer, or may be a co-extruded film made of the acid-modified olefin resin and one or more olefin resins,
[0029]
The inner layer 50 may be a film made of the acid-modified olefin resin single layer, but may be a co-extruded film made of the acid-modified olefin resin and one or more olefin resins (hereinafter, referred to as general olefin resin). The general olefin resin may be, as the ethylene resin, for example, low-density polyethylene, medium-density polyethylene, high-density polyethylene, linear low-density polyethylene, ethylene-butene copolymer, and the like, Examples of the propylene resin include homo-type polypropylene, random-type polypropylene, block-type polypropylene, ethylene-propylene copolymer, and ethylene-propylene-butene copolymer.
[0030]
The total thickness of the inner layer 50 may be 25 μm or more, preferably 30 to 50 μm. If the thickness is less than 25 μm, sufficient heat sealing strength cannot be obtained, and there is a risk of leakage of contents and breakage of the bag due to an increase in internal pressure. In consideration of cost, volume, and energy density by weight, the total thickness of the inner layer 50 is desirably 100 μm or less. When the inner layer 50 is a co-extruded film, the thickness of the acid-modified olefin resin is 5 μm or more, preferably 10 μm or more. If it is less than 5 μm, sufficient heat sealing strength cannot be obtained.
[0031]
The adhesive layer 40 may be formed by a well-known dry lamination method using a two-component curable polyurethane-based adhesive composed of a polyol component and an isocyanate component. Examples of the polyol component include polyester polyols, polyester polyurethane polyols, polyether polyols, and polyether polyurethane polyols. Examples of the isocyanate component include diisocyanates such as TDI, MDI, HDI, PIDI, and XDI, and starting materials thereof. The thickness is 2 to 5 μm, preferably 3 to 4 μm.
[0032]
Generally, as shown in FIGS. 2 and 3, a lithium battery is provided with a metal terminal such as aluminum or nickel for projecting the stored electricity to protrude outside, but a package using the laminate of the present invention is used. In the above, when the innermost layer is an acid-modified olefin resin, the metal terminal portion can be sufficiently sealed, but when the innermost layer is an olefin resin, both the innermost layer and the metal terminal are thermally bonded. For example, by interposing a film made of an acid-modified olefin resin between the innermost layer and the metal terminal, the metal terminal portion can be sufficiently sealed.
[0033]
【Example】
Next, the present invention will be described in more detail with reference to the following examples.
First, an aluminum foil (40 μm) having both surfaces chemically converted (phosphoric acid chromate treatment) with a chemical conversion treatment solution comprising three components of a phenol resin, a chromium fluoride (trivalent) compound, and phosphoric acid in advance. (Thickness) and a biaxially stretched nylon film having a thickness of 25 μm were bonded together via a two-component curable polyurethane-based adhesive to prepare a primary laminate.
[0034]
Example 1
A 50 μm-thick unsaturated carboxylic acid graft-modified random polypropylene (hereinafter referred to as R-PPa) film graft-modified with an unsaturated carboxylic acid having a thickness of 120 μm was formed on the surface of the first laminate prepared above. ° C to prepare an intermediate laminate bonded by a thermal lamination method, and then reheat the intermediate laminate to 180 ° C to obtain a laminate of the present invention.
[0035]
Example 2
A 50 μm-thick unsaturated carboxylic acid graft-modified linear low density polyethylene (hereinafter referred to as LLDPEa) film graft-modified with an unsaturated carboxylic acid having a thickness of 50 μm was formed on the surface of the primary laminate prepared above. The laminate was heated to 110 ° C. to prepare an intermediate laminate bonded by a thermal lamination method, and then the intermediate laminate was reheated to 160 ° C. to obtain a laminate of the present invention.
[0036]
Example 3
A two-layer co-extruded film composed of 5 μm thick LLDPEa and 55 μm thick linear low-density polyethylene (hereinafter, referred to as LLDPE) is applied to the surface of the chemical conversion treatment layer of the primary laminate prepared above. Are heated so that the surface of the chemical conversion treatment layer is heated to 110 ° C. to produce an intermediate laminated body bonded by a thermal lamination method, and then the intermediate laminated body is reheated to 160 ° C. Thus, a laminate of the present invention was obtained.
[0037]
Example 4
A two-layer co-extruded film made of R-PPa having a thickness of 10 μm and random polypropylene having a thickness of 20 μm (hereinafter, referred to as R-PP) was formed on the surface of the chemical conversion treatment layer of the primary laminate prepared above. R-PPa is brought into contact, and the chemical conversion treatment layer is heated to 120 ° C. to produce an intermediate laminate bonded by a thermal lamination method, and then the intermediate laminate is heated to 180 ° C. To obtain a laminate of the present invention.
[0038]
Example 5
Three-layer co-extrusion of 5 μm-thick R-PPa, 20 μm-thick homopolypropylene (hereinafter referred to as H-PP) and 10 μm-thick R-PP on the surface of the chemical conversion treatment layer of the primary laminate prepared above. The film was heated so that the R-PPa was in contact with the surface of the chemical conversion treatment layer, and the surface of the chemical conversion treatment layer was heated to 120 ° C. to produce an intermediate laminate that was bonded by a thermal lamination method. The laminate was reheated to 180 ° C. to obtain a laminate of the present invention.
[0039]
Example 6
Unsaturated carboxylic acid graft-modified homopolypropylene (hereinafter referred to as H-PPa) graft-modified with a 10 μm-thick unsaturated carboxylic acid on the surface of the chemical conversion treatment layer of the primary laminate prepared above, and 20 μm-thick H-PP The two-layer co-extruded film consisting of the H-PPa is brought into contact with the chemical conversion treatment layer surface, and the chemical conversion treatment surface is heated to 120 ° C., and the intermediate laminate is bonded by a thermal lamination method. After the production, the intermediate laminate was reheated to 180 ° C. to obtain a laminate of the present invention.
[0040]
Comparative Example 1
On the surface of the chemical conversion treatment layer of the primary laminate prepared above
The R-PPa particles were dispersed in toluene to make a 25% by weight dispersion and applied by a roll coating method, and dried at 180 ° C. to form an R-PPa film having a thickness of 5 μm. The -PPa film was heated to 140 ° C., and a 30 μm-thick R-PP film was bonded to the R-PPa film surface by a thermal lamination method to obtain a laminate as a comparative example.
[0041]
Laminate strength, electrolytic solution resistance, and water permeation amount were evaluated by the following evaluation methods for Examples 1 to 6 and Comparative Example 1 produced above, and the results are shown in Table 1.
[0042]
[Table 1]

*) Lamination strength:
The adhesive strength between the chemical conversion treatment layer and the inner layer of the aluminum foil was measured using Tensilon at a tensile speed of 50 mm / min. The measured values are average values of 20 samples.
*) Electrolyte resistance:
3 g of an electrolyte solution [dissolve lithium hexafluorophosphate in a mixed solution [ethylene carbonate / diethyl carbonate / dimethyl carbonate = 1/1/1 (volume ratio)], and form a 1 mol / liter lithium hexafluorophosphate solution A three-side sealed bag with an inner size of 30 × 50 mm and a heat seal width of 7 mm filled with aluminum foil is stored for 336 hours in a thermostat at 85 ° C. for 336 hours. And measured at a pulling speed of 50 mm / min. The measured values are average values of 20 samples.
*) Moisture permeability:
A three-side sealed bag filled with 3 g of a mixed solution [ethylene carbonate / diethyl carbonate / dimethyl carbonate = 1/1/1 (volume ratio)] and having an inner size of 30 × 50 mm and a heat seal width of 7 mm is placed at 60 ° C. and 90% RH. Was stored for 1440 hours in a thermo-hygrostat, and the increase in water content was measured by the Karl Fischer method. Note that the measured values are average values of five samples.
[0043]
As is clear from Table 1, the laminates of Examples 1 to 6 are particularly resistant to an electrolytic solution and have a very small decrease in lamination strength as compared with Comparative Example 1. did it.
[0044]
【The invention's effect】
As described in detail above, the laminate of the present invention is extremely remarkable in that it has excellent sealing properties and strong lamination strength, has a low moisture permeation amount when used as a lithium battery package, and is particularly excellent in electrolytic solution resistance. It is effective. Further, the method for producing a laminate of the present invention can produce a laminate having the above-mentioned remarkable effects with high production efficiency.
[Brief description of the drawings]
FIG. 1 is a diagram schematically illustrating a layer configuration of an embodiment of a laminate according to the present invention.
FIG. 2 is a diagram illustrating an embodiment of a package used for a lithium battery.
FIG. 3 is a diagram illustrating another embodiment of a package used for a lithium battery.
[Explanation of symbols]
1, 1 'laminate
10 Outer layer
20 Chemical conversion treatment layer
30 aluminum foil
40 adhesive layer
50 Inner layer

Claims (9)

In a laminate comprising an outer layer, an aluminum foil, and an inner layer and at least a chemical conversion treatment layer provided on the inner layer side surface of the aluminum foil, a resin layer in contact with the chemical conversion treatment surface of the inner layer is made of an acid-modified olefin resin. A laminate, wherein the surface of the chemical conversion treatment layer and a single layer film of the acid-modified olefin resin or a co-extruded film of the acid-modified olefin resin and at least one olefin resin are bonded by a thermal lamination method. The laminate according to claim 1, wherein the inner layer is a single-layer film made of an ethylene resin graft-modified with an unsaturated carboxylic acid. The laminate according to claim 1, wherein the inner layer is a single-layer film made of a propylene resin graft-modified with an unsaturated carboxylic acid. The laminate according to claim 1, wherein the inner layer is a co-extruded film composed of an ethylene resin graft-modified with an unsaturated carboxylic acid and one or more ethylene resins. The laminate according to claim 1, wherein the inner layer is a co-extruded film including a propylene resin layer graft-modified with an unsaturated carboxylic acid and one or more propylene resin layers. The laminate according to any one of claims 4 and 5, wherein the ethylene resin or the propylene resin graft-modified with the unsaturated carboxylic acid of the co-extruded film has a thickness of at least 5 µm. The laminate according to any one of claims 1 to 6, wherein the inner layer has a thickness of 25 µm or more. The laminate according to claim 1, wherein a chemical conversion treatment layer is provided on a surface on the outer layer side of the aluminum foil. Laminating the outer layer and the other side of the aluminum foil provided with a chemical conversion treatment layer on at least one side, and a single-layer film of an acid-modified olefin resin or a co-polymerization of the acid-modified olefin resin and one or more olefin resins. While heating the inner layer composed of an extruded film so that the chemical conversion treatment layer has a temperature of not less than the softening point of the acid-modified olefin resin and the melting point or less, the acid-modified olefin resin of the inner layer is in contact with the chemical conversion treatment layer. A method for producing a laminate, comprising: a step of laminating the intermediate laminate by a thermal lamination method to form an intermediate laminate; and a step of heating the intermediate laminate to a temperature not lower than the melting point of the acid-modified olefin resin.

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