Packaging material and package using the same

Abstract

To provide a laminate that includes an aluminum foil, that enables the aluminum foil and resin layers to be easily peeled and separated, and that enables recycling.SOLUTION: According to the present invention, provided is a laminate including resin layers on both surfaces of an aluminum foil, in which the resin layer contains one or two or more types of additives selected from the group consisting of carboxylic acid, ionic crystal composed of hydroxide ion, water-soluble polysaccharide, and superabsorbent polymer, and the additives are contained in the resin layer by more than or equal to 10 mass % and less than or equal to 90 mass %.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to a laminate in which resin layers are laminated on both sides of an aluminum foil, and in particular to a laminate (aluminum foil laminate) in which the resin layer contains a predetermined amount of one or more additives selected from the group consisting of carboxylic acids, ionic crystals consisting of hydroxide ions, water-soluble polysaccharides, and highly water-absorbent polymers. [Background technology]

[0002] Traditionally, aluminum foil with a resin layer laminated on it has been widely used as a packaging material for food and pharmaceuticals, and for industrial parts, due to its light weight, ease of formability, strength, barrier properties, light blocking properties, and chemical resistance.

[0003] In recent years, there has been a demand for recyclability in resin products, and packaging materials made only of resin have been actively recycled. On the other hand, the reality is that packaging materials made of laminates containing aluminum foil have not been recycled sufficiently because it is difficult to separate the aluminum foil from the resin layer.

[0004] Therefore, in order to achieve a high level of recyclability while taking advantage of the characteristics of aluminum foil, a method for enhancing the separability between the aluminum foil and the laminated resin layer has been studied. For example, JP 47-034572 A (Patent Document 1) discloses a method for separating the resin layer and the aluminum foil by dissolving at least a part of the aluminum foil. In addition, JP 2010-023845 A (Patent Document 2) proposes a paper-aluminum foil liquid container in which the paper base layer and the barrier layer made of aluminum foil can be peeled off after use. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 47-034572 [Patent Document 2] JP 2010-023845 A Summary of the Invention [Problem to be solved by the invention]

[0006] However, the technology described in Patent Document 1 requires the use of a hazardous substance such as nitric acid (HNO3) as a solution for separating the aluminum foil, and when considering the handling of the solution and the treatment of the waste liquid after use in the separation, there is a problem that the environmental load is large and it cannot be easily applied. Also, the technology described in Patent Document 2 has a problem that a resin layer remains on the surface of the aluminum foil even after peeling and separation.

[0007] Therefore, an object of the present invention is to provide a laminate which includes an aluminum foil, but in which the aluminum foil and the resin layer can be easily peeled and separated, making it recyclable. [Means for solving the problem]

[0008] The present inventors have conducted intensive research to solve the above problems, and have found that the above problems can be solved by laminating a resin layer containing a specific amount of a specific additive on both sides of an aluminum foil, and have completed the present invention. That is, the laminate of the present invention is a laminate having a resin layer on both sides of an aluminum foil, the resin layer containing one or more additives selected from the group consisting of carboxylic acid, ionic crystals consisting of hydroxide ions, water-soluble polysaccharides, and highly water-absorbent polymers, and the additives are contained in the resin layer in an amount of 10% by mass to 90% by mass. The above additives exhibit high chemical solubility in an aqueous solution containing an acid and an ionic chloride. Therefore, by immersing the laminate after use in the aqueous solution as described above, the aluminum foil in contact with the resin layer can be dissolved, and the resin layer can be separated more easily.

[0009] In the present invention, the aluminum foil contains Al, Fe, Ni and Zn, and when the contents of Fe, Ni and Zn in the aluminum foil are [Fe], [Ni] and [Zn], respectively, in mass%, it is preferable that [Zn] is 0.4 to 5.1, [Fe] + [Ni] is 0.4 to 4.8, and [Fe] + [Ni] + 2 × [Zn] is 2.5 or more. By using an aluminum foil of the above composition, the surface of the aluminum foil in contact with the resin layer is also quickly dissolved, making it possible to separate the resin layer even more easily.

[0010] Furthermore, even when sodium hydroxide, nitric acid, hydrochloric acid, etc. are used, the amount of these acids used and the immersion time can be reduced, further improving the ease of handling during recycling.

[0011] That is, although the laminate of the present invention includes an aluminum foil having high barrier properties, the resin layer alone can be easily separated, achieving a high level of recyclability.

[0012] In the present invention, from the viewpoint of ensuring the amount of aqueous solution containing an acid and an ionic chloride required to dissolve the aluminum foil and the functions and strength required of a foil laminate, such as barrier properties, it is preferable that the thickness of the aluminum foil is 5 μm or more and 100 μm or less.

[0013] In the present invention, the additive is preferably one or more additives selected from the group consisting of citric acid, tartaric acid, Ca(OH)2, sugar, glucomannan, and sodium polyacrylate.

[0014] In the present invention, for the purpose of further enhancing or complementing the functions and strength required for a laminate such as a packaging material, such as barrier properties, it is preferable that the resin layer on at least one side of the resin layers laminated on both sides of the aluminum foil is formed from two or more different resin layers. Effect of the Invention

[0015] In the laminate of the present invention, the resin layer contains a predetermined amount of a specific additive such as carboxylic acid, so that the additive dissolves in an aqueous solution containing an acid or ionic chloride, or an alkaline aqueous solution, or the moisture in these aqueous solutions penetrates into the resin layer, or the resin layer gels as it absorbs the water from the aqueous solution, thereby facilitating peeling and separation of the aluminum foil and the resin layer. [Brief description of the drawings]

[0016] [Figure 1A] 1 is an SEM photograph (×1000 magnification) of an aluminum foil surface of foil A4 in which the area occupancy rate of second phase particles having an equivalent circle diameter of 0.1 μm or more is 6.38%. [Figure 1B] 1 is an SEM photograph (×1000 magnification) of the surface of aluminum foil A12, in which the area occupancy rate of second phase particles having an equivalent circle diameter of 3.0 μm or more is 1.69%. [Figure 2A] 1 is an SEM photograph (×1000 magnification) of the surface of aluminum foil B6 in which the area occupancy rate of second phase particles having an equivalent circle diameter of 0.1 μm or more is 3.85%. [Figure 2B] 1 is an SEM photograph (×1000 magnification) of the surface of aluminum foil B9 in which the area occupancy rate of second phase particles having an equivalent circle diameter of 3.0 μm or more is 7.55%. [Diagram 3] This is a scatter plot showing the relationship between ([Fe] + [Ni] + 2 × [Zn]) and chemical solubility in a weak acid environment (labeled "weak acid solubility" in the figure). DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] Hereinafter, a laminate (aluminum foil laminate) according to one embodiment of the present invention will be described in detail with reference to the drawings. Note that the present invention is not limited to the examples shown below, and various modifications are possible within the scope of the technical idea of ​​the present invention.

[0018] 1.Laminate The laminate of the present invention is a laminate having a resin layer on both sides of an aluminum foil, the resin layer containing one or more additives selected from the group consisting of carboxylic acids, ionic crystals consisting of hydroxide ions, water-soluble polysaccharides, and highly water-absorbent polymers, and the additives are contained in the resin layer in an amount of 10% by mass to 90% by mass. The configuration of the laminate of the present invention will be described in detail below.

[0019] 2.Laminate structure (1) Aluminum foil <Aluminum foil> In the present invention, the aluminum foil is a foil mainly composed of aluminum. The aluminum foil also includes an aluminum alloy foil. In addition, unlike a material having an aluminum vapor deposition film, the aluminum foil has high barrier properties regardless of the composition. That is, if the material has an aluminum foil, high barrier properties are ensured.

[0020] The composition of the aluminum foil used in the present invention is not particularly limited, but in addition to aluminum (Al), it may contain iron (Fe), nickel (Ni), zinc (Zn) and inevitable impurities as long as the manufacturing suitability of the aluminum foil is not impaired.

[0021] The inevitable impurities are composed of one or more elements selected from the group consisting of silicon (Si), manganese (Mn), magnesium (Mg), copper (Cu), indium (In), tin (Sn), sodium (Na), vanadium (V), titanium (Ti), zirconium (Zr), chromium (Cr), boron (B), gallium (Ga), bismuth (Bi), lead (Pb), antimony (Sb) and arsenic (As). In the present invention, the content of aluminum (Al) contained in the aluminum foil is preferably 89.0 mass% or more.

[0022] <Iron (Fe)> When a certain amount of Fe is added to aluminum, it forms Al-Fe second phase particles and / or Al-Fe-Ni second phase particles together with Ni. The second phase particles containing Fe act as cathode sites that are more noble in potential than the aluminum parent phase, improving the chemical solubility of aluminum foil in acidic environments, including weak acids.

[0023] If the Fe content exceeds 3.1% by mass, the material strength increases due to precipitation strengthening, and defects such as cracks occur, hindering rolling workability. Furthermore, coarse second phase particles are easily formed during casting, which hinders rolling workability and causes defects such as pinholes in the process of manufacturing aluminum foil with a thickness of 10 μm or less. The lower limit of the Fe content is not particularly limited, but is usually about 0.0001% by mass. In order to make the Fe content less than 0.0001% by mass, it is necessary to repeat the three-layer electrolysis method, which significantly increases the manufacturing cost. Therefore, the Fe content in the aluminum foil is preferably 0.0001% by mass or more and 3.1% by mass or less, more preferably 0.0001% by mass or more and 1.8% by mass or less, and even more preferably 0.0001% by mass or more and 1.5% by mass or less.

[0024] <Nickel (Ni)> Adding a certain amount of Ni to aluminum forms Al-Ni second phase particles and / or Al-Fe-Ni second phase particles together with Fe. The Ni-containing second phase particles have a large potential difference with the aluminum matrix, which increases their effect as cathode sites. Therefore, adding Ni to aluminum improves the chemical solubility of aluminum foil in acidic environments, including weak acids.

[0025] If the Ni content exceeds 3.0% by mass, the material strength increases due to precipitation strengthening, and defects such as cracked edges occur, hindering rolling workability. Furthermore, coarse second phase particles are easily formed during casting, which hinders rolling workability and causes defects such as pinholes in the process of manufacturing aluminum foil with a thickness of 10 μm or less. The lower limit of the Ni content is not particularly limited, but is usually about 0.0001% by mass. In order to make the Ni content less than 0.0001% by mass, it is necessary to repeat the three-layer electrolysis method, which significantly increases the manufacturing cost. Therefore, the Ni content in the aluminum foil is preferably 0.0001% by mass or more and 3.0% by mass or less, more preferably 0.0001% by mass or more and 2.6% by mass or less, and even more preferably 0.0001% by mass or more and 1.8% by mass or less.

[0026] <Zinc (Zn)> When a certain amount of Zn is added to aluminum, most of it dissolves in the aluminum matrix, making the potential of the aluminum matrix less noble. This increases the potential difference between the Al-Fe, Al-Ni and / or Al-Fe-Ni second phase particles and the aluminum matrix, improving the chemical solubility of the aluminum foil in acidic environments, including weak acids.

[0027] If the Zn content is less than 0.4% by mass, the amount of Zn dissolved in the aluminum parent phase is reduced, the effect of making the potential of the aluminum parent phase less base is insufficient, and the chemical solubility of the aluminum foil in an acidic environment containing a weak acid is impaired. On the other hand, if the Zn content exceeds 2.1% by mass and further increases, the chemical solubility is impaired. If the Zn content exceeds 5.1% by mass, the material strength increases due to solid solution strengthening, hindering rolling workability. Therefore, the Zn content in the aluminum foil is preferably 0.4% by mass or more and 5.1% by mass or less, more preferably 0.5% by mass or more and 2.9% by mass or less, and even more preferably 0.75% by mass or more and 2.1% by mass or less.

[0028] <[Fe]+[Ni]> Adding a certain amount of Fe or Ni to aluminum will result in the formation of Al-Fe, Al-Ni and / or Al-Fe-Ni second phase particles. These second phase particles have a particularly large potential difference with the aluminum matrix, and therefore act as cathode sites, improving the chemical solubility of aluminum foil in acidic environments, including weak acids.

[0029] When the content of Fe and Ni in the aluminum foil is [Fe] and [Ni], respectively, in mass%, if [Fe] + [Ni] is less than 0.4, the number of second phase particles decreases, the effect as a cathode site for the aluminum matrix is ​​not sufficient, and the chemical solubility of the aluminum foil in an acidic environment containing a weak acid becomes insufficient. If [Fe] + [Ni] exceeds 4.8, the material strength increases due to precipitation strengthening, and defects such as edge cracks occur, hindering rolling workability. Therefore, [Fe] + [Ni] is preferably 0.4 to 4.8, more preferably 0.9 to 4.0, and even more preferably 1.4 to 2.9.

[0030] <[Fe] + [Ni] + 2 × [Zn]> Adding a certain amount of Fe or Ni to aluminum will result in the formation of Al-Fe, Al-Ni and / or Al-Fe-Ni second phase particles. These second phase particles have a particularly large potential difference with the aluminum matrix, and therefore act as cathode sites, improving the chemical solubility of aluminum foil in acidic environments, including weak acids.

[0031] In addition, when a certain amount of Zn is added to aluminum, most of it dissolves in the aluminum matrix, which has the effect of making the potential of the aluminum matrix less noble. This increases the potential difference between the Al-Fe, Al-Ni and / or Al-Fe-Ni second phase particles and the aluminum matrix with Zn dissolved in it, further improving the chemical solubility of the aluminum foil in an acidic environment that contains a weak acid.

[0032] When the contents of Fe, Ni, and Zn in the aluminum foil are expressed as [Fe], [Ni], and [Zn] in mass%, respectively, if [Fe] + [Ni] + 2×[Zn] is less than 2.5, the synergistic effect of the effects of adding the aforementioned Fe and Ni and the effect of adding Zn becomes insufficient, and the chemical solubility of the aluminum foil in an acidic environment containing a weak acid becomes insufficient. Therefore, [Fe] + [Ni] + 2×[Zn] is preferably 2.5 or more, more preferably 2.85 or more, and even more preferably 2.95 or more.

[0033] <Zn solid solution content> The more Zn exists in a solid solution state in the aluminum matrix phase, the lower the potential of the aluminum matrix phase becomes, and the chemical solubility of the aluminum foil in an acidic environment containing a weak acid is improved. By having chemical solubility, the resin layer and the aluminum foil can be peeled off cleanly.

[0034] When the Zn solid solution content exceeds 4.1 mass%, the material strength increases due to solid solution strengthening, which inhibits the rolling processability. When the Zn solid solution content is less than 0.3 mass%, the effect of lowering the potential of the aluminum matrix phase becomes insufficient, and the chemical solubility of the aluminum foil in an acidic environment containing a weak acid is impaired. Therefore, in the aluminum foil, the Zn solid solution content dissolved in the aluminum matrix phase is preferably 0.3 mass% or more and 4.1 mass% or less, more preferably 0.4 mass% or more and 2.7 mass% or less, and even more preferably 0.5 mass% or more and 1.5 mass% or less.

[0035] <Impurities> In addition to the above elements, the aluminum foil may contain one or more elements selected from the group consisting of Si, Mn, Mg, Cu, In, Sn, Na, V, Ti, Zr, Cr, B, Ga, Bi, Pb, Sb, and As as inevitable impurities. The total content of the one or more elements is preferably 0.6% by mass or less. In particular, the content of Mn in the aluminum foil is preferably 0.4% by mass or less, the content of Mg is preferably 0.4% by mass or less, and the content of each of the above elements other than Mn and Mg contained as inevitable impurities in the aluminum foil is preferably 0.2% by mass or less.

[0036] <si> Adding a certain amount of silicon to aluminum improves the chemical solubility of aluminum foil in an acidic environment containing a weak acid. However, if the silicon content exceeds 0.2 mass%, it promotes the coarsening of second phase particles of Al-Fe, Al-Ni, and / or Al-Fe-Ni, impairing rolling workability.

[0037] The lower limit of the Si content is not particularly limited, but is usually about 0.0001% by mass. In order to make the Si content less than 0.0001% by mass, it is necessary to repeat the three-layer electrolysis method, which significantly increases the manufacturing cost. Therefore, the Si content in the aluminum foil is preferably 0.0001% by mass or more and 0.2% by mass or less, more preferably 0.0001% by mass or more and 0.15% by mass or less, and even more preferably 0.0001% by mass or more and 0.1% by mass or less.

[0038] When a certain amount of Mn is added to aluminum, most of it dissolves in the aluminum matrix, but some of it forms second-phase particles such as Al-Mn, Al-Mn-Ni, Al-Mn-Si, Al-Mn-Fe-Ni, Al-Mn-Ni-Si, Al-Mn-Si-Fe, or Al-Mn-Fe-Ni-Si together with Al-Mn, Fe, Ni, and Si. When the Mn content exceeds 0.4 mass%, the Mn content in the second-phase particles and the amount of Mn dissolved in the aluminum matrix increase, and the potential of the second-phase particles approaches the potential of the aluminum matrix, reducing the effect of the second-phase particles as cathode sites. This reduces the chemical solubility of the aluminum foil in an acidic environment containing weak acids.

[0039] The lower limit of the Mn content is not particularly limited, but is usually about 0.0001% by mass. In order to make the Mn content less than 0.0001% by mass, it is necessary to repeat the three-layer electrolysis method, which significantly increases the manufacturing cost. Therefore, the Mn content in the aluminum foil is preferably 0.0001% by mass or more and 0.4% by mass or less, more preferably 0.0001% by mass or more and 0.2% by mass or less, and even more preferably 0.0001% by mass or more and 0.1% by mass or less.

[0040] <mg> When a certain amount of Mg is added to aluminum, some of it dissolves in the aluminum parent phase. When the Mg content exceeds 0.4 mass%, Mg is concentrated in the oxide film formed on the surface of the aluminum material, which makes the oxide film more likely to have defects. Such defects in the oxide film can cause delamination at the bonding interface of a laminate in which aluminum foil and a resin film are laminated. In addition, the addition of Mg has the effect of reducing the chemical solubility of aluminum foil.

[0041] The lower limit of the Mg content is not particularly limited, but is usually about 0.0001% by mass. In order to make the Mg content less than 0.0001% by mass, it is necessary to repeat the three-layer electrolysis method, which significantly increases the manufacturing cost. Therefore, the Mg content in the aluminum foil is preferably 0.0001% by mass or more and 0.4% by mass or less, more preferably 0.0001% by mass or more and 0.2% by mass or less, and even more preferably 0.0001% by mass or more and 0.1% by mass or less.

[0042] <cu> When a certain amount of Cu is added to aluminum, some of it dissolves in the aluminum matrix. If the Cu content exceeds 0.2 mass%, the amount of Cu dissolved in the aluminum matrix increases, and the material strength increases due to solid solution strengthening, which may impair rolling workability.

[0043] The lower limit of the Cu content is not particularly limited, but is usually about 0.0001% by mass. In order to make the Cu content less than 0.0001% by mass, it is necessary to repeat the fractional crystallization method in addition to the three-layer electrolysis method, which significantly increases the manufacturing cost. Therefore, the Cu content in the aluminum foil is preferably 0.0001% by mass or more and 0.2% by mass or less, more preferably 0.0001% by mass or more and 0.15% by mass or less, and even more preferably 0.0001% by mass or more and 0.1% by mass or less.

[0044] <In、Sn> When a certain amount of In and / or Sn is added to aluminum, most of them are dissolved in the aluminum parent phase, and the potential of the aluminum parent phase is made lower. This increases the potential difference between the Al-Fe, Al-Ni and / or Al-Fe-Ni second phase particles and the aluminum parent phase in which In and / or Sn are dissolved, improving the chemical solubility of the aluminum foil in a weak acid environment. When the amount of In and / or Sn added exceeds 0.2 mass%, the effect of making the potential of the aluminum parent phase lower is saturated and the rolling processability is hindered. Therefore, the In content in the aluminum foil is preferably 0.0001 mass% or more and 0.2 mass% or less, and the Sn content is preferably 0.0001 mass% or more and 0.2 mass% or less.

[0045] <Area occupancy rate of second phase particles with a circle equivalent diameter of 0.1 μm or more distributed on the aluminum foil surface> Adding the above elements to aluminum produces second-phase particles in the aluminum matrix. Specifically, these second-phase particles are Al-Fe, Al-Ni and / or Al-Fe-Ni, etc. These second-phase particles have a large potential difference with the aluminum matrix and act as cathode sites. This improves the chemical solubility of the aluminum foil in an acidic environment containing a weak acid.

[0046] In the aluminum foil, when the area occupancy of the second phase particles having a circle equivalent diameter of 0.1 μm or more distributed on the surface falls below 1.7%, the effect as a cathode site is not sufficient, and the chemical solubility of the aluminum foil in an acidic environment containing a weak acid becomes insufficient. Therefore, the area occupancy of the second phase particles having a circle equivalent diameter of 0.1 μm or more on the aluminum foil surface is preferably 1.7% or more, more preferably 4.1% or more, and even more preferably 5.6% or more.

[0047] <Area occupancy rate of second phase particles having a circle equivalent diameter of 3.0 μm or more distributed on the aluminum foil surface> Adding the above elements to aluminum produces second-phase particles in the aluminum matrix. Specifically, these second-phase particles are Al-Fe, Al-Ni, and / or Al-Fe-Ni, etc., and coarse second-phase particles with an equivalent circle diameter of 3.0 μm or more impair rolling workability.

[0048] In an aluminum foil, if the area occupancy of second-phase particles having an equivalent circle diameter of 3.0 μm or more distributed on the surface exceeds 2.0%, defects such as edge cracks will occur and rolling workability will be impaired. Therefore, the area occupancy of second-phase particles having an equivalent circle diameter of 3.0 μm or more on the aluminum foil surface is preferably 2.0% or less, more preferably 0.8% or less, and even more preferably 0.5% or less.

[0049] <Thickness of aluminum foil> The thickness of the aluminum foil used in the present invention is not particularly limited as long as it has the above composition and can be set arbitrarily, but is preferably 5 μm to 100 μm, more preferably 7 μm to 65 μm. In particular, when the aluminum foil is thick, there are fewer pinholes and tears during molding in the laminate with the resin film, which is preferable. If the aluminum foil is too thicker than 100 μm, the rigidity becomes too large and the flexibility of the laminate becomes poor, so that there is a risk of uneven heat sealing occurring due to one-sided contact, etc. If it is too thin, pinholes may easily occur in the aluminum foil, and its function as a packaging material may be reduced. To control the thickness of the aluminum foil within the above range, casting and rolling may be performed according to a conventional method. In addition, heat treatment may be performed appropriately for the purpose of homogenizing the aluminum foil.

[0050] (2) Resin layer In the present invention, the resin layer is a layer made of a resin formed (laminated) on both sides of an aluminum foil. The resin layer may be a single layer, or may have a multi-layer structure in which a plurality of resin layers are laminated. In the present invention, the resin layer formed on one side of the aluminum foil may be the same as or different from the resin layer formed on the other side.

[0051] The resin layer applied to the present invention may be a layer made of a resin film or a layer made of a resin coat. The type of resin layer can be appropriately selected depending on the printability, strength, heat sealability, and other performance required for the packaging material. In particular, in the present invention, at least one of the resin layers preferably has thermal adhesiveness. When the resin layer has thermal adhesiveness, it becomes easy to form the package by processing such as heat sealing.

[0052] At least one of the resin layers is preferably formed from two or more resin layers, which allows the other layers to compensate for the characteristics that cannot be achieved by a single layer alone.

[0053] In the present invention, the resin layer can be made of a known resin material, and is not particularly limited. Specifically, for example, known printing inks made of one or more resins selected from epoxy, nitrocellulose, polyvinyl butyral, phenolic resin, maleic acid resin, alkyd resin, chlorinated polypropylene resin, vinyl chloride-vinyl acetate copolymer resin, acrylic resin, modified olefin resin, etc. can be used. Also, for example, one or more known adhesives selected from polyurethane adhesives, epoxy adhesives, acrylic adhesives, polypropylene adhesives, polyester adhesives, vinyl chloride adhesives, vinyl chloride-vinyl acetate copolymer adhesives, modified olefin adhesives, etc. can be used. Furthermore, for example, resin films made of one or more resins selected from polyethylene, polypropylene, polyester, polyamide (nylon), (meth)acrylic, polyvinyl chloride, polystyrene, polyvinylidene chloride, ethylene-vinyl acetate copolymer saponified product, polyvinyl alcohol, polycarbonate, polyvinyl acetate, acetal, etc. can be used.

[0054] In the present invention, the resins constituting the resin layers on both sides may be the same or different. Among the above resins, the resins capable of exhibiting thermal adhesiveness are polyurethane resin, polypropylene resin, polyester resin, vinyl chloride resin, chlorinated polypropylene resin, vinyl chloride-vinyl acetate copolymer resin, acrylic resin, modified olefin resin, ethylene-vinyl acetate copolymer, and polycarbonate resin. As described above, by forming a resin layer capable of exhibiting thermal adhesiveness on at least one side of the aluminum foil, it becomes possible to easily form the aluminum foil into a package by processing such as heat sealing.

[0055] The method for bonding the resin film to the aluminum foil when laminating the two may be any of a wide variety of known adhesion and lamination methods, and is not particularly limited.Specific examples include the dry lamination method using a two-liquid curing adhesive such as a polyester urethane adhesive or a polyester adhesive, the co-extrusion method, the extrusion coating method, the extrusion lamination method, the heat sealing method, and the heat lamination method using an anchor coating agent.

[0056] As a method for forming a resin coating layer on an aluminum foil, any known method can be used, for example, a method of coating with a coating agent such as roll coating, various gravure coatings, doctor blade coating, comma coater, spray coating, brush coating, spin coating, bar coating, flow coating, dip coating or die coating, or a coating method that combines two or more of the above coating methods may be used, and further, a heating treatment for drying or reaction may be performed after coating.

[0057] Other methods for forming a resin coating layer include surface treatment methods such as ion plasma treatment, ion plating treatment, sputtering treatment, vapor deposition treatment, and plating treatment, or a surface treatment method that combines two or more of the above surface treatment methods may be used. Furthermore, a lamination method for a resin coating layer that combines one or more of the above coating methods and one or more of the above surface treatment methods may be used.

[0058] In addition, for the resin coating layer laminated on the aluminum foil, surface modification using plasma treatment, fatty acids, silane coupling agents, etc., and modified products formed using acids and / or alkalis, etc. can be suitably used, and there are no particular limitations.

[0059] In the present invention, the thickness of one resin layer can be appropriately determined depending on the properties required for the packaging of the final product, but is preferably in the range of, for example, 1 μm to 250 μm. The amount of resin formed is not particularly limited, but is preferably 0.1 g / m 2 More than 100g / m 2 The range can be set as follows: 2 More than 10g / m 2 Less than 1 g / m, more preferably 2 More than 5g / m 2 The following may be adopted:

[0060] (3) Additives <Additives> In the present invention, the additive is contained in the resin layer laminated on both sides of the aluminum foil. The additive may be one or more additives selected from the group consisting of carboxylic acid, ionic crystals consisting of hydroxide ions, water-soluble polysaccharides, and highly water-absorbent polymers. There is no particular restriction on the form of the additive contained in the resin layer, and the additive may be dissolved in the resin layer, or the granular additive may be dispersed in the resin layer, or the additive may be unevenly distributed on the surface or near the center of the resin layer.

[0061] In the present invention, the resin layer contains a predetermined amount of a specific additive such as carboxylic acid, so that the additive dissolves in an aqueous solution containing an acid or an ionic chloride, or an alkaline aqueous solution, or the moisture in these aqueous solutions penetrates into the resin layer, or the resin layer gels by absorbing the water from the aqueous solution, thereby facilitating peeling and separation of the aluminum foil and the resin layer.

[0062] The additive may be one or more of ionic crystals made of carboxylic acid or hydroxide ion, etc. In particular, a combination of carboxylic acid, ionic crystals made of hydroxide ion, water-soluble polysaccharide, highly water-absorbent polymer, etc. is preferable because it increases the acid or alkali concentration locally in the resin layer containing the additive and further promotes the reaction caused by the water-soluble polysaccharide or highly water-absorbent polymer.

[0063] In the present invention, the type and content of additives contained in each resin layer laminated on both sides of the aluminum foil may be the same or different. The additive is preferably contained in the resin layer in an amount of 10% by mass or more and 90% by mass or less. If the content of additives is less than 10% by mass, peeling and detachment between the aluminum foil and the resin layer may not proceed sufficiently, and there is a risk that the two cannot be separated. On the other hand, if the content of additives exceeds 90% by mass, there is a risk that sufficient adhesion cannot be obtained between the resin layer and the aluminum foil.

[0064] <Carboxylic acid> Carboxylic acid is an organic acid that has at least one carboxyl group (-COOH). In an aqueous solution, at least a portion of the carboxylic acid added to the resin layer ionizes and becomes acidic, dissolving the interface of the aluminum foil and peeling and detaching the aluminum foil from the resin layer. In addition, since the carboxylic acid itself is water-soluble, an aqueous solution containing an acid and an ionic chloride, or an alkaline aqueous solution, penetrates into the resin layer to which the carboxylic acid has been added, and this has the effect of promoting the peeling and detachment of the aluminum foil from the resin layer.

[0065] Specifically, the carboxylic acids include unsaturated fatty acids such as oleic acid, linoleic acid, linolenic acid, arachidonic acid, eicosapentaenoic acid, docosahexaenoic acid, and sorbic acid, hydroxy acids such as lactic acid (2-hydroxypropanoic acid), malic acid (2-hydroxybutanedioic acid), and citric acid (2-hydroxypropanetricarboxylic acid), aromatic carboxylic acids such as benzoic acid (benzenecarboxylic acid), phthalic acid (benzene-1,2-dicarboxylic acid), isophthalic acid (benzene-1,3-dicarboxylic acid), terephthalic acid (benzene-1,4-dicarboxylic acid), salicylic acid (2-hydroxybenzenecarboxylic acid), and gallic acid (3,4,5-trihydroxybenzenecarboxamide). One or more carboxylic acids may be used that are selected from the group consisting of carboxylic acid, mellitic acid (benzenehexacarboxylic acid), cinnamic acid (3-phenylprop-2-enoic acid), dicarboxylic acids oxalic acid (ethanedioic acid), malonic acid (propanedioic acid), succinic acid (butanedioic acid), glutaric acid (pentanedioic acid), adipic acid (hexanedioic acid), fumaric acid ((E)-but-2-enedioic acid), maleic acid ((Z)-but-2-enedioic acid), tricarboxylic acid aconitic acid (2-carboxyprop-1-entricarboxylic acid), oxocarboxylic acid pyruvic acid (2-oxopropanoic acid) and oxaloacetic acid (2-oxobutanedioic acid).

[0066] From the viewpoint of ease of handling of the resin layer, the carboxylic acid is preferably a solid at room temperature, and from the viewpoint of environmental load in particular, it is more preferable to use a carboxylic acid synthesized from a natural source, such as citric acid or tartaric acid.

[0067] <Ionic crystals made of hydroxide ions> Examples of ionic crystals consisting of hydroxide ions (hereinafter referred to as "hydroxide ion crystals") include sodium hydroxide (NaOH), potassium hydroxide (KOH), calcium hydroxide (Ca(OH)2), and barium hydroxide (Ba(OH)2). Hydroxide ion crystals are preferred as additives to be included in the resin layer because they remove the oxide film on the surface of the aluminum foil and promote the peeling and detachment of the resin layer from the aluminum foil. In particular, among hydroxide ion crystals, Ca(OH)2, also known as slaked lime, is recognized as a solid food additive at room temperature, so it is more preferred to use slaked lime Ca(OH)2 from the viewpoint of reducing the environmental load.

[0068] <Water-soluble polysaccharides> Water-soluble polysaccharides are preferred as additives to be added to the resin layer because they gel when the water in the aqueous solution penetrates the resin layer or when the resin layer contains the water in the aqueous solution, and therefore promote the peeling or detachment of the resin layer from the aluminum foil. Examples of water-soluble polysaccharides include starch, glycogen, cellulose, etc., and among these, it is more preferred to use glucomannan and methylcellulose, which form a three-dimensional network structure with water and gel.

[0069] <Super absorbent polymer> A highly water-absorbent polymer is preferred as an additive to be included in the resin layer because the water from the aqueous solution penetrates the resin layer or the resin layer gels when it absorbs the water from the aqueous solution, thereby promoting peeling or detachment of the resin layer from the aluminum foil.

[0070] The superabsorbent polymer is defined in JIS K7223 as a superabsorbent polymer with a water absorption capacity of 10 g / g or more. Among them, for example, [nonionic]: polyvinyl alcohol, polyvinylpyrrolidone, polyacrylamide, poly(N-alkyl)acrylamide, polyhydroxyethyl acrylate, polyvinyl methyl ether, [anionic]: partial alkali metal salts such as polyacrylic acid, poly(isobutylene-maleic acid), poly(2-acrylamido-2-methylpropane-sulfonic acid), poly(methacryloyloxypropanesulfonic acid), and polyvinylphosphonic acid, [cationic]: poly(methacryloyloxyethyl quaternary ammonium chloride), N,N-dimethyl-N-(3-acrylamidopropyl)-N-(carboxylmethyl)ammonium inner salt, etc., are listed. Among them, it is preferable to use a superabsorbent polymer of a polyacrylate salt type such as sodium polyacrylate, which shows a water absorption capacity of 100 to 1000 g / g in pure water, forms a three-dimensional network structure, and gels. EXAMPLES

[0071] The features of the present invention will be further clarified below with reference to examples and comparative examples.

[0072] 1. Aluminum foil <Preparation of aluminum foil> Each aluminum composition having the composition shown in Tables 1 and 2 was melted, and the aluminum composition was melted and cast at a cooling rate of 1°C / sec or more and 15°C / sec or less by a mold casting method to obtain an aluminum ingot. The obtained aluminum ingot was then heat treated at 530°C for 5 hours. Then, cold rolling was performed several times to a thickness of 50 μm to produce aluminum foils A1 to 45 shown in Table 1 and aluminum foils B1 to 16 shown in Table 2.

[0073] [Table 1]

[0074] [Table 2]

[0075] <Measurement of aluminum foil composition> The analysis of each component in the aluminum foil was carried out by weighing out 1.00 g of each aluminum foil and measuring it using an inductively coupled plasma emission spectrometer (Shimadzu Corporation: ICPS-8100). The results are shown in Tables 1 and 2. The detection limit of each element by the above measurement method is 0.01 mass%, so in Tables 1 and 2, all elements below the detection limit are shown as 0.00%.

[0076] <Calculation of the circle equivalent diameter and measurement of the area occupancy rate of second phase particles distributed on the aluminum foil surface> The calculation of the circle equivalent diameter and the measurement of the area occupancy rate of the second phase particles distributed on the aluminum foil surface were performed by the following method. That is, the measurement samples were prepared by mirror-finishing the surfaces of the aluminum foils in Tables 1 and 2 using polishing cloths (MD-Mol and MD-Nap, manufactured by Struers Corporation) and diamond suspensions (Diapro Mol R 3 μm and Diapro Nap R 1 μm, manufactured by Struers Corporation).

[0077] The surface area occupancy rate of the second phase particles on each sample surface was measured using backscattered electron images obtained by observing the sample surface with a field emission scanning electron microscope (FE-SEM). Specifically, ten rectangular fields randomly selected from the backscattered electron images of each sample surface were observed. The range of each rectangular field was 0.01069 mm 2 The backscattered electron image of each rectangular field was binarized using image processing software (Mitani Shoji Co., Ltd.: WinROOF2021) under the condition of brightness of 100 to 255, to extract second phase particles with a circle equivalent diameter of 0.1 μm or more and second phase particles with a circle equivalent diameter of 3.0 μm or more.

[0078] The area occupancy rate of the second phase particles in the measurement surface (rectangular field) was calculated using the above-mentioned image processing software for each of the second phase particles having an equivalent circle diameter of 0.1 μm or more and the equivalent circle diameter of 3.0 μm or more extracted in this manner, and the average value of the above calculation results obtained from 10 rectangular fields was taken as the area occupancy rate of the second phase particles. The results are shown in Tables 1 and 2.

[0079] As an example of SEM photographs before binarization, Fig. 1A shows an SEM photograph of the aluminum foil surface of foil A4, in which the area occupancy of second-phase particles having a circle-equivalent diameter of 0.1 μm or more is 6.38%, and Fig. 1B shows an SEM photograph of the aluminum foil surface of foil A12, in which the area occupancy of second-phase particles having a circle-equivalent diameter of 3.0 μm or more is 1.69%. Fig. 2A shows an SEM photograph of the aluminum foil surface of foil B6, in which the area occupancy of second-phase particles having a circle-equivalent diameter of 0.1 μm or more is 3.85%, and Fig. 2B shows an SEM photograph of the aluminum foil surface of foil B9, in which the area occupancy of second-phase particles having a circle-equivalent diameter of 3.0 μm or more is 7.55%.

[0080] <Evaluation of chemical solubility of aluminum foil in a weak acid environment> The chemical solubility of the aluminum foil surface in a weak acid environment was evaluated by the following method. That is, each aluminum foil in Tables 1 and 2 was cut into a size of 40 mm x 40 mm, and as a pretreatment, it was immersed in a 1 mass% sodium hydroxide solution at 35 ° C for 60 seconds, and then immersed in a 30 mass% nitric acid solution at 25 ° C for 60 seconds to prepare a test piece for measurement. Each test piece was immersed in an aqueous solution containing 3 mass% sodium chloride and 3 mass% acetic acid at 40 ° C for 2700 seconds, and the mass before and after immersion was measured to calculate the dissolution loss per unit surface area of ​​each test piece. As a result, the dissolution loss per unit surface area of ​​the test piece was 2.8 μg / mm 2 The above were evaluated as having sufficient chemical solubility, and the results are shown in Tables 1 and 2.

[0081] <Evaluation of rolling processability of aluminum foil> The rolling workability of the aluminum foil was evaluated by the following method. That is, in the cold rolling process, when the ingots (cast bodies) of each aluminum having the composition shown in Tables 1 and 2 were cold rolled to a predetermined thickness, the rolling workability of the sample (aluminum foil) in which the reduction in material width due to edge cracking was less than 3% of the material width before the start of cold rolling was evaluated as "A", the rolling workability of the sample in which the reduction in material width due to edge cracking was 3% or more but less than 10% was evaluated as "B", the rolling workability of the sample in which the reduction in material width due to edge cracking was 10% or more but less than 25% was evaluated as "C", and the rolling workability of the sample in which the reduction in material width due to edge cracking was 25% or more was evaluated as "F". The results are shown in Tables 1 and 2.

[0082] <Measurement of the amount of Zn dissolved in aluminum foil> The amount of Zn dissolved in the aluminum foil was measured by the following method. That is, 0.1 g of a sample was taken from each aluminum foil in Tables 1 and 2, and only the aluminum parent phase in the aluminum foil was dissolved with phenol, and the second phase particles were collected by filtering with a membrane filter (H100A047A, manufactured by Toyo Roshi Kaisha, Ltd.) having a pore size of 0.1 μm. The second phase particles were dissolved with acid and alkali, and the amount of Zn precipitated was determined using an inductively coupled plasma emission spectrometer (ICPS-8100, manufactured by Shimadzu Corporation). The amount of Zn dissolved in the aluminum foil was determined by subtracting the amount of Zn precipitated from the Zn content of the entire aluminum foil. The results are shown in Table 3.

[0083] <Measurement of natural potential and cathodic polarization curve of aluminum foil> In order to investigate the effects of the composition of the aluminum foil, the area occupancy rate of the second phase particles, and the amount of Zn in the solid solution on the chemical solubility, the absolute values ​​of the natural potential and cathodic current density were set at 1 mA / cm 2 The potential was measured when it reached

[0084] Specifically, the above-mentioned potential measurements were carried out by the following method at a temperature of 25° C. and open to the atmosphere. Also, each aluminum foil in Tables 1 and 2 was cut into a size of 15 mm×17 mm, and as a pretreatment, it was immersed in a 1% by mass sodium hydroxide solution at 35° C. for 15 seconds, and then immersed in a 30% by mass nitric acid solution at 25° C. for 30 seconds to prepare a test piece.

[0085] The potential was measured using a corrosion cell VM1 manufactured by EC Frontier Co., Ltd. The test solution was a 25°C, pH 5.5, 5 mass% NaCl aqueous solution, the counter electrode was a platinum-plated titanium rod (counter electrode VM1-5 manufactured by EC Frontier Co., Ltd.), the reference electrode was an Ag / AgCl reference electrode RE-1A manufactured by EC Frontier Co., Ltd., and the working electrode sample holder was a sample holder VM1-3 manufactured by EC Frontier Co., Ltd. The electrode potential was measured by a three-electrode method. The sample holder had an area of ​​1 cm 2 The surface of the test piece exposed through the sample window serves as a working electrode.

[0086] The absolute values ​​of the natural potential and cathodic current density are 1 mA / cm 2 The potential when reaching was measured by first immersing the working electrode, counter electrode, and reference electrode in the test solution and leaving it to stand for 600 seconds. During this time, the electrode potential was measured at sampling intervals of 10 seconds, and the average value of 60 points was taken as the "natural potential" of the aluminum foil. Next, the natural potential of each test piece was swept in the negative direction to -1500 mV at a sweep rate of 0.5 mV / s using a potentiostat (Hokuto Denko Corporation: Electrochemical Measurement System HZ-7000 Series) to measure the cathodic polarization curve. In this cathodic polarization curve, the absolute value of the current density was 1 mA / cm 2 The electrode potential was read when the absolute value of the cathode current density of the aluminum foil reached 1 mA / cm. 2 The results are shown in Table 3.

[0087] [Table 3]

[0088] From Table 3, for example, in aluminum foil, when the amount of Zn in solid solution increases and the potential of the aluminum parent phase becomes less noble, the natural potential in the measurement also becomes less noble. Also, for example, when the contents of Fe and Ni in the aluminum foil are [Fe] and [Zn] in mass%, if the portion acting as a cathode site for the aluminum parent phase increases due to an increase in [Fe]+[Ni] or an increase in the area occupancy rate of second-phase particles with a circle equivalent diameter of 0.1 μm or more, the natural potential in the measurement becomes less noble with a smaller potential sweep. 2 Therefore, the absolute value of the cathode current density of the aluminum foil is 1 mA / cm 2 It can be determined that the greater the "potential when the potential reaches the natural potential," that is, the closer it is to the natural potential, the greater the number of portions that act as cathode sites.

[0089] <Considerations on aluminum foil> The aluminum foils A1 to A45 shown in Table 1 have a dissolution loss per unit surface area of ​​2.8 μg / mm in a weak acid environment. 2 As described above, the rolling workability when cold rolled was evaluated as "A," "B," or "C" (see Table 1), which shows that all aluminum foils have excellent chemical solubility in a weak acid environment and excellent rolling workability.

[0090] On the other hand, the aluminum foils B1 to B16 shown in Table 2 have a dissolution loss per unit surface area of ​​2.8 μg / mm in a weak acid environment. 2 Since the evaluation of rolling workability when cold-rolled was "F" (see Table 2), it was found that good results were not obtained in at least one of the evaluations of chemical solubility in a weak acid environment and rolling workability.

[0091] FIG. 3 shows the relationship between [Fe] + [Ni] + 2 × [Zn] and the weak acid solubility (μg / mm 2 ) is shown in a scatter plot.

[0092] Comparing the aluminum foils (foils A1 to 45) shown in Table 1 with the aluminum foils (foils B1 to 16) shown in Table 2, Tables 1 and 2 and Figures 3 and 4 show that the chemical solubility in a weak acid environment is 2.8 μg / mm 2 As described above, it was found that in order to obtain aluminum foil with a rolling processability evaluation of "A," "B," or "C," [Zn] needs to be 0.4 or more and 5.1 or less, [Fe] + [Ni] needs to be 0.4 or more and 4.8 or less, and [Fe] + [Ni] + 2 × [Zn] needs to be 2.5 or more.

[0093] This is thought to be because, based on the measurement results of the natural potential and cathodic polarization curve for the amount of Zn in solid solution in aluminum foil shown in Table 3, by adding Fe, Ni, and Zn to aluminum and controlling [Zn], [Fe] + [Ni], and [Fe] + [Ni] + 2 × [Zn], it is possible to make the potential of the aluminum parent phase more base and the potential of the second phase particles distributed in the aluminum foil more noble, thereby improving the chemical solubility of the aluminum foil.

[0094] In addition, from Tables 1 and 2, in order to obtain an aluminum foil having excellent chemical solubility and rolling processability in the above-mentioned weak acid environment, it is preferable that the Fe content is at least 0.0001% by mass or more and 3.1% by mass or less, the Ni content is preferably 0.0001% by mass or more and 3.0% by mass or less, the Zn solid solution amount is preferably 0.3% by mass or more and 4.1% by mass or less, the inevitable impurities are one or more elements selected from the group consisting of Si, Mn, Mg, Cu, In, Sn, Na, V, Ti, Zr, Cr, B, Ga, Bi, Pb, Sb and As, the total content of the one or more elements is 0.6% by mass or less, the Mn content is 0.4% by mass or less, and the Mg content is preferably 0.4% by mass or less, and the content of each of the above elements other than Mn and Mg contained as inevitable impurities is preferably 0.2% by mass or less.

[0095] Furthermore, from Tables 1 and 2, it was found that the area occupancy of second phase particles having an equivalent circle diameter of 0.1 μm or more distributed on the aluminum foil surface is preferably 1.7% or more, and the area occupancy of second phase particles having an equivalent circle diameter of 3.0 μm or more distributed on the aluminum foil surface is preferably 2.0% or less.

[0096] 2. Aluminum foil laminate <Preparation of a laminate using aluminum foil> Based on the evaluation results of the chemical solubility of the above-mentioned aluminum foils in a weak acid environment (see Tables 1 and 2), aluminum foils A4, 16, 22, 38, and 9, which have excellent chemical solubility in weak acids, aluminum foils B2 and 6, which have the same composition as general-purpose aluminum foils, and general-purpose aluminum foil C (manufactured by Toyo Aluminum: 8079 material) and general-purpose aluminum foil D (manufactured by Toyo Aluminum: 8021 material) described below were used, and resin layers with different types and amounts of additives added to both sides were laminated to produce laminates of Examples 1 to 22 and Comparative Examples 1 to 5, and the effect of the additives contained in the resin layer on the separability of the aluminum foil and resin layer of each laminate was investigated.

[0097] [Example 1] First, an ester-based resin (DICG: base LX-500, solid content 60% by mass) and a hardener (KW-75, solid content 75% by mass) were prepared as the resin. 100 parts by weight, 10 parts by weight, and 115 parts by weight of the base resin, hardener, and ethyl acetate were mixed until the color was uniform, to prepare a 30% by mass urethane resin solution. In addition, 34.3 parts by weight of citric acid (manufactured by Fujifilm Wako Pure Chemical Industries: citric acid, Wako special grade) as an additive, 50 parts by weight of water, and 30 parts by weight of ethanol were mixed until the citric acid powder was dissolved to prepare a 30% by mass citric acid solution. The prepared 30% by mass urethane resin solution, the prepared 30% by mass citric acid solution, and ethyl acetate were mixed in amounts of 10 parts by weight, 10 parts by weight, and 20 parts by weight, respectively, to prepare a resin layer coating liquid containing additives. The coating liquid was mixed just before coating, and the weight of the mixed liquid after drying with a bar coater #26 was 5.0 g / m 2 (The additive weight ratio of the resin layer is 50% by mass, 2.5g / m 2 ) on the glossy side of A4 aluminum foil, and dried at 100°C for 1 minute to form a resin layer containing the additives. Next, a 12 μm thick polyethylene terephthalate film (Toyobo: E5100, density 1.4 g / cm 3 ) was laminated to the glossy side of the A4 aluminum foil using a small laminator at a nip temperature of 60° C. and a speed of 5 m / min. Furthermore, a resin layer containing an additive was formed on the matte side of the aluminum foil A4 in the same manner as the glossy side, and a polyethylene terephthalate film (Toyobo: E5100, density 1.4 g / cm) with a thickness of 12 μm was applied. 3 ) were bonded together and cured at 40° C. for 2 days to prepare a laminate of Example 1.

[0098] [Example 2] As a coating liquid for the resin layer containing additives, a mixture of 2 parts by weight, 18 parts by weight, and 20 parts by weight of the 30% by weight urethane resin solution, 30% by weight citric acid solution, and ethyl acetate prepared in Example 1, respectively, was used, and the amount of the resin layer formed was 5.0 g / m 2 The additive weight ratio of the resin layer is 90% by mass, or 4.5g / m 2 A laminate of Example 2 was produced in the same manner as in Example 1, except that:

[0099] [Example 3] As a coating liquid for the resin layer containing additives, a mixture of 18 parts by weight, 2 parts by weight, and 20 parts by weight of the 30% by weight urethane resin solution, 30% by weight citric acid solution, and ethyl acetate prepared in Example 1, respectively, was used, and the amount of the resin layer formed was 5.0 g / m 2 The additive weight ratio of the resin layer is 10% by mass, or 0.5 g / m 2 A laminate of Example 3 was produced in the same manner as in Example 1, except that the above-mentioned conditions were satisfied.

[0100] [Example 4] The coating solution of Example 1 was mixed just before coating, and the weight of the mixed solution after drying with bar coater #36 was 10.0 g / m 2 The coating was applied to the glossy side of A4 aluminum foil so that the coating weight was 30.0 g / m2, and the coating was dried at 100°C for 1 minute and 30 seconds. This process was then repeated two more times until the weight after drying was 30.0 g / m2. 2 (The additive weight ratio of the resin layer is 50% by mass, 15.0 g / m 2 A resin layer containing an additive was formed so as to obtain a resin layer having a thickness of 100 nm or less. Next, a 12 μm thick polyethylene terephthalate film (Toyobo: E5100, density 1.4 g / cm 3 ) was laminated to the glossy side of the aluminum foil using a small laminator at a nip temperature of 60° C. and a speed of 5 m / min. Furthermore, a resin layer containing an additive was formed on the matte side of the aluminum foil A4 in the same manner as the glossy side, and a polyethylene terephthalate film (Toyobo: E5100, density 1.4 g / cm) with a thickness of 12 μm was applied. 3 ) was laminated together and cured at 40° C. for 2 days to prepare a laminate of Example 4.

[0101] [Example 5] The coating solution of Example 1 was mixed just before coating, and the weight of the mixed solution after drying with bar coater #12 was 1.0 g / m 2 (The additive weight ratio of the resin layer is 50% by mass, 0.5g / m 2 ) on the glossy side of A4 aluminum foil, and then dried at 100°C for 1 minute to form a resin layer containing the additives. Next, a 12 μm thick polyethylene terephthalate film (Toyobo: E5100, density 1.4 g / cm 3 ) was laminated to the glossy side of the A4 aluminum foil using a small laminator at a nip temperature of 60° C. and a speed of 5 m / min. Furthermore, a resin layer containing an additive was formed on the matte side of the aluminum foil A4 in the same manner as the glossy side, and a polyethylene terephthalate film (Toyobo: E5100, density 1.4 g / cm) with a thickness of 12 μm was applied. 3 ) was laminated together and cured at 40° C. for 2 days to prepare a laminate of Example 5.

[0102] [Example 6] Instead of the citric acid solution used in Example 1, tartaric acid (manufactured by Fujifilm Wako Pure Chemical Industries: L+ tartaric acid) was used as an additive, and 3 parts by weight, 11 parts by weight, and 6 parts by weight of ethanol were mixed until the tartaric acid powder was dissolved, to prepare a 15% by mass tartaric acid solution. The 30% by weight urethane resin solution of Example 1, the 15% by weight tartaric acid solution, and 10 parts by weight of ethyl acetate were mixed together to prepare a resin layer coating liquid containing additives. The coating liquid was mixed just before coating, and the weight of the mixed liquid after drying with a bar coater #26 was 5.0 g / m 2 (The additive weight ratio of the resin layer is 50% by mass, 2.5g / m 2 ) on the glossy side of A4 aluminum foil, and dried at 100°C for 1 minute to form a resin layer containing the additives. Next, a 12 μm thick polyethylene terephthalate film (Toyobo: E5100, density 1.4 g / cm 3 ) was laminated to the glossy side of the A4 aluminum foil using a small laminator at a nip temperature of 60° C. and a speed of 5 m / min. A urethane resin layer containing citric acid was formed on the poppy side of the aluminum foil A4 in the same manner as in Example 1, and a polyethylene terephthalate film having a thickness of 12 μm was attached to it to prepare a laminate of Example 6.

[0103] [Example 7] Instead of the citric acid solution used in Example 1, 3 parts by weight and 7 parts by weight of calcium hydroxide (calcium hydroxide manufactured by Fuji Film Wako Pure Chemical Industries, Ltd.) and ethyl acetate were mixed as additives to prepare a 30% by mass calcium hydroxide dispersion. The 30% by weight urethane resin solution of Example 1, the 30% by weight calcium hydroxide dispersion, and ethyl acetate were mixed in amounts of 10 parts by weight, 10 parts by weight, and 10 parts by weight, respectively, to prepare a resin layer coating liquid containing additives. The coating liquid was mixed just before coating, and the weight of the mixed liquid after drying with bar coater #18 was 5.0 g / m 2 (The additive weight ratio of the resin layer is 50% by mass, 2.5g / m 2 ) on the glossy side of A4 aluminum foil, and dried at 100°C for 1 minute to form a resin layer containing the additives. Next, a 12 μm thick polyethylene terephthalate film (Toyobo: E5100, density 1.4 g / cm 3 ) was laminated to the glossy side of the A4 aluminum foil using a small laminator at a nip temperature of 60° C. and a speed of 5 m / min. A calcium hydroxide-containing urethane resin layer was formed on the poppy side of the A4 aluminum foil in the same manner as on the glossy side of the aluminum foil, and a 12 μm-thick polyethylene terephthalate film was laminated to produce a laminate of Example 7.

[0104] [Example 8] Instead of the citric acid solution used in Example 1, citric acid (manufactured by Fujifilm Wako Pure Chemical Industries: citric acid, Wako special grade) as an additive, sugar (manufactured by Dai-Nippon Meiji Sugar Co., Ltd.: granulated sugar) as another additive, water, and ethanol were mixed in amounts of 6 parts by weight, 24 parts by weight, 110 parts by weight, and 60 parts by weight, respectively, until the citric acid powder and sugar powder were dissolved, to prepare a 15% by mass citric acid-sugar solution. The prepared 30% by weight urethane resin solution of Example 1 and the 15% by weight citric acid-sugar solution were mixed at 10 parts by weight and 20 parts by weight, respectively, to prepare a resin layer coating liquid containing additives. The coating liquid was mixed just before coating, and the weight of the mixed liquid after drying with a bar coater #26 was 5.0 g / m 2 (The additive weight ratio of the resin layer is 50% by mass, 2.5g / m 2 ) on the glossy side of A4 aluminum foil, and dried at 100°C for 1 minute to form a resin layer containing the additives. Next, a 12 μm thick polyethylene terephthalate film (Toyobo: E5100, density 1.4 g / cm 3 ) was laminated to the glossy side of the A4 aluminum foil using a small laminator at a nip temperature of 60° C. and a speed of 5 m / min. A urethane resin layer containing citric acid-sugar was formed on the poppy side of the A4 aluminum foil in the same manner as on the glossy side of the aluminum foil, and a 12 μm thick polyethylene terephthalate film was laminated to produce the laminate of Example 8.

[0105] [Example 9] Instead of the citric acid solution used in Example 1, citric acid (manufactured by Fujifilm Wako Pure Chemical Industries: citric acid, Wako special grade) as an additive, glucomannan (Nature One: glucomannan powder) as an additive, ethyl acetate, and methanol were mixed in amounts of 6 parts by weight, 24 parts by weight, 70 parts by weight, and 100 parts by weight, respectively, to prepare a 15% by mass citric acid-glucomannan dispersion solution. The 30% by weight urethane resin solution prepared in Example 1 and the 15% by weight citric acid-glucomannan solution as an additive were mixed in amounts of 10 parts by weight and 20 parts by weight, respectively, to prepare a resin layer coating liquid containing the additive. The coating liquid was mixed just before coating, and the weight of the mixed liquid after drying with a bar coater #26 was 5.0 g / m 2 (The additive weight ratio of the resin layer is 50% by mass, 2.5g / m 2 ) on the glossy side of A4 aluminum foil, and dried at 100°C for 1 minute to form a resin layer containing the additives. Next, a 12 μm thick polyethylene terephthalate film (Toyobo: E5100, density 1.4 g / cm 3 ) was laminated to the glossy side of the A4 aluminum foil using a small laminator at a nip temperature of 60° C. and a speed of 5 m / min. A urethane resin layer containing citric acid-glucomannan was formed on the poppy side of the aluminum foil A4 in the same manner as on the glossy side of the aluminum foil, and a 12 μm thick polyethylene terephthalate film was laminated to produce the laminate of Example 9.

[0106] [Example 10] Instead of the citric acid solution used in Example 1, citric acid (manufactured by Fujifilm Wako Pure Chemical Industries: citric acid, Wako special grade) as an additive, sodium polyacrylate (Margo Corporation: sodium polyacrylate, food additive grade) as another additive, ethyl acetate, and methanol were mixed in amounts of 6 parts by weight, 24 parts by weight, 70 parts by weight, and 100 parts by weight, respectively, to prepare a 15% by mass citric acid-sodium polyacrylate dispersion solution. The prepared 30 mass % urethane resin solution of Example 1 and the 15 mass % citric acid-sodium polyacrylate solution were mixed in amounts of 10 parts by weight and 20 parts by weight, respectively, to prepare a resin layer coating liquid containing additives. The coating liquid was mixed just before coating, and the weight of the mixed liquid after drying with a bar coater #26 was 5.0 g / m 2 (The additive weight ratio of the resin layer is 50% by mass, 2.5g / m 2 ) on the glossy side of A4 aluminum foil, and dried at 100°C for 1 minute to form a resin layer containing the additives. Next, a 12 μm thick polyethylene terephthalate film (Toyobo: E5100, density 1.4 g / cm 3 ) was laminated to the glossy side of the A4 aluminum foil using a small laminator at a nip temperature of 60° C. and a speed of 5 m / min. A urethane resin layer containing citric acid-sodium polyacrylate was formed on the poppy side of the A4 aluminum foil in the same manner as on the glossy side of the aluminum foil, and a 12 μm thick polyethylene terephthalate film was laminated to produce the laminate of Example 10.

[0107] [Example 11] A laminate of Example 11 was produced in the same manner as in Example 1, except that aluminum foil A16 was used instead of aluminum foil A4.

[0108] [Example 12] A laminate of Example 12 was produced in the same manner as in Example 1, except that aluminum foil A22 was used instead of aluminum foil A4.

[0109] [Example 13] A laminate of Example 13 was produced in the same manner as in Example 1, except that aluminum foil A38 was used instead of aluminum foil A4.

[0110] [Example 14] A laminate of Example 14 was produced in the same manner as in Example 1, except that aluminum foil A9 was used instead of aluminum foil A4.

[0111] [Example 15] A laminate of Example 15 was produced in the same manner as in Example 1, except that aluminum foil B2 was used instead of aluminum foil A4.

[0112] [Example 16] A laminate of Example 16 was produced in the same manner as in Example 1, except that aluminum foil B6 was used instead of aluminum foil A4.

[0113] [Example 17] The laminate of Example 17 was produced in the same manner as in Example 1, except that general-purpose aluminum foil C (manufactured by Toyo Aluminum: 8079 material, containing 0.17% by mass of Si, 1.0% by mass of Fe, 0.05% by mass of Cu, 0.1% by mass of Zn, and 0.05% by mass or less of other elements) was used instead of aluminum foil A4.

[0114] [Example 18] The laminate of Example 18 was produced in the same manner as in Example 1, except that a general-purpose aluminum foil D (manufactured by Toyo Aluminum: 8021 material, containing 0.15% by mass of Si, 1.4% by mass of Fe, 0.05% by mass of Cu, and 0.05% by mass or less of other elements) was used instead of the aluminum foil A4.

[0115] [Example 19] A laminate of Example 19 was produced in the same manner as in Example 1, except that no polyethylene terephthalate film was attached to both sides of the A4 aluminum foil. Since the urethane resin layer was adhesive, the laminate of Example 19 was handled by sandwiching it between release films.

[0116] [Example 20] A nitrocellulose solution (SF1009 Clear NT, manufactured by DICG, solids content 20% by mass) was used instead of the urethane resin solution used in Example 1, and 30 parts by weight, 20 parts by weight, and 50 parts by weight of the 20% by mass nitrocellulose solution, the 30% by mass citric acid solution of Example 1, and MEK were mixed to prepare a coating liquid for the resin layer containing additives. The coating liquid was mixed just before coating, and the weight of the mixed liquid after drying with a bar coater #26 was 5.0 g / m 2 (The additive weight ratio of the resin layer is 50% by mass, 2.5g / m 2 ) on the glossy side of A4 aluminum foil, and dried at 100°C for 1 minute to form a resin layer containing the additives. Furthermore, a resin layer containing an additive was formed on the matte side of the aluminum foil A4 in the same manner as on the glossy side, to prepare a laminate of Example 20.

[0117] [Example 21] Instead of the urethane resin solution used in Example 1, a vinyl chloride vinyl acetate copolymer solution (Leader: LD#S837G Clear, 21% solids by weight diluted with MEK to make the solids content 20% by weight) was used, and the 20% vinyl chloride vinyl acetate copolymer solution, the 30% citric acid solution of Example 1, and 30 parts by weight, 20 parts by weight, and 50 parts by weight of MEK were mixed to prepare a coating liquid for the resin layer containing additives. The coating liquid was mixed just before coating, and the weight of the mixed liquid after drying with a bar coater #26 was 5.0 g / m 2 (The additive weight ratio of the resin layer is 50% by mass, 2.5g / m 2 ) on the glossy side of A4 aluminum foil, and dried at 120°C for 1 minute to form a resin layer containing the additives. Furthermore, a resin layer containing an additive was formed on the matte side of the aluminum foil A4 in the same manner as on the glossy side, to prepare a laminate of Example 21.

[0118] [Example 22] A laminate of Example 22, which is the same as that of Example 1, was produced in the same manner as in Example 1.

[0119] [Comparative Example 1] The coating liquid was a 30% by mass urethane resin solution alone, and the weight after drying with bar coater #12 was 5.0 g / m 2 The resin was applied to the glossy side of A4 aluminum foil so as to form a resin layer by drying at 100°C for 1 minute. Next, a 12 μm thick polyethylene terephthalate film (Toyobo: E5100, density 1.4 g / cm 3 ) was laminated to the glossy side of the A4 aluminum foil using a small laminator at a nip temperature of 60° C. and a speed of 5 m / min. Furthermore, a resin layer was formed on the matte side of the aluminum foil A4 in the same manner as the glossy side, and a polyethylene terephthalate film (Toyobo: E5100, density 1.4 g / cm) with a thickness of 12 μm was applied. 3 ) were bonded together and cured at 40° C. for 2 days to produce a laminate of Comparative Example 1. That is, the laminate of Comparative Example 1 was a laminate that did not contain any additive in the resin layer.

[0120] [Comparative Example 2] As a coating liquid for the resin layer containing additives, a mixture of the 30% by mass urethane resin solution prepared in Example 1, a 30% by mass citric acid solution as an additive, and ethyl acetate was used in an amount of 1.8 parts by weight, 18.2 parts by weight, and 20 parts by weight, respectively, to form a resin layer of 5.0 g / m 2 The additive weight ratio of the resin layer is 91% by mass, or 4.6 g / m 2 A laminate of Comparative Example 2 was produced in the same manner as in Example 1, except that the above-mentioned conditions were satisfied.

[0121] [Comparative Example 3] As a coating liquid for the resin layer containing additives, a mixture of the 30% by mass urethane resin solution prepared in Example 1, a 30% by mass citric acid solution as an additive, and ethyl acetate was used in an amount of 18.2 parts by weight, 1.8 parts by weight, and 20 parts by weight, respectively, to form a resin layer of 5.0 g / m 2 The additive weight ratio of the resin layer is 9 mass% (0.46 g / m 2 A laminate of Comparative Example 3 was produced in the same manner as in Example 1, except that the above-mentioned conditions were satisfied.

[0122] [Comparative Example 4] The laminate of Comparative Example 4 was produced in the same manner as in Comparative Example 1, except that general-purpose aluminum foil C (manufactured by Toyo Aluminum: 8079 material, containing 0.17% by mass of Si, 1.0% by mass of Fe, 0.05% by mass of Cu, 0.1% by mass of Zn, and 0.05% by mass or less of other elements) was used instead of aluminum foil A4.

[0123] [Comparative Example 5] Nitrocellulose solution (SF1009 Clear NT, solid content 20% by mass) was applied using bar coater #18 to a substrate with a weight of 5.0 g / m2 after drying. 2 The resin was applied to the glossy side of A4 aluminum foil so as to form a resin layer by drying at 100°C for 1 minute. Furthermore, a resin layer was formed on the matte surface of the aluminum foil A4 in the same manner as on the glossy surface side, to prepare a laminate of Comparative Example 5.

[0124] <Evaluation of the effect of additives in the resin layer on the separation of the aluminum foil and the resin layer> [Evaluation test 1] (1) Immersion desorption test (acid-saline solution) 300 mL of an aqueous solution containing 3% by mass of acetic acid and 18% by mass of sodium chloride was heated in a beaker in a water bath to 60° C. Then, each laminate sample of Examples 1 to 21 and Comparative Examples 1 to 5 was cut into a size of 10 mm×10 mm. Next, the obtained test piece was immersed in the aqueous solution of acetic acid and sodium chloride.

[0125] (2) Immersion desorption test (alkaline solution) 300 mL of a 3% by mass aqueous solution of sodium hydroxide was placed in a beaker and heated in a water bath to 35° C. Then, a laminate sample of Example 22 was cut into a size of 10 mm×10 mm. Next, the obtained test piece was immersed in the acetic acid-sodium chloride aqueous solution.

[0126] (3) Evaluation criteria for the immersion desorption test The test pieces in which the resin layer separated from the aluminum foil in the aqueous solution within 30 minutes were rated as "A", those in which the resin layer separated from the aluminum foil in the aqueous solution within 2 hours were rated as "B", those in which the resin layer separated from the aluminum foil in the aqueous solution within 5 hours were rated as "C", and those in which the resin layer did not separate from the aluminum foil in the aqueous solution even after 5 hours were rated as "D".

[0127] [Evaluation test 2] (1) Laminate strength The lamination strength of each laminate was measured on the glossy side of Examples 1 to 18 and 22 and Comparative Examples 1 to 4, where polyethylene terephthalate was bonded. The laminate was cut into a piece 15 mm long x 200 mm wide with the lamination direction being the vertical direction, and peeled between the polyethylene terephthalate film and the aluminum foil. The test results were the average value of N=5 at a tensile speed of 200 mm / min and a peel angle of 90°.

[0128] (2) Evaluation criteria for laminate strength Laminate strengths of 2.0N / 15mm or more were evaluated as "A", those less than 2.0N / 15mm and 1.0N / 15mm or more were evaluated as "B", those less than 1.0N / 15mm and 0.5N / 15mm or more were evaluated as "C", and those less than 0.5N / 15mm were evaluated as "D".

[0129] [Evaluation test 3] (1) Cross-cut test The cross-cut test was carried out on the glossy side of Examples 19, 20, and 21 and Comparative Example 5, which are laminate samples for which it is difficult to measure the laminate strength, based on the cross-cut test of JIS K5600-5-6 (1999). 25 squares were cut into a cross shape at 2 mm intervals from the glossy side of each laminate. Cellophane tape (Nichiban: 18 mm Cellophane Tape 405, registered trademark) was attached to the cross-cut portion and peeled off at an angle of about 60° to confirm the peeling state.

[0130] (2) Evaluation criteria for cross-cut test If the result was within classification 4 in "Table 1 Classification of Test Results" of JIS K5600-5-6 (1999), it was rated as "E" (Excellent), and if the result was beyond classification 4 and adhesion was poor, it was rated as "F" (Failing). In addition, category 4 in "Table 1 Classification of Test Results" is defined as "The coating has undergone major partial or complete peeling along the edges of the cuts and / or has undergone partial or complete peeling in several locations. The area of ​​the cross-cut area affected does not clearly exceed 35%."

[0131] Table 4 shows the results of evaluation tests 1, 2, and 3 conducted on each of the laminates of Examples 1 to 22 and Comparative Examples 1 to 5. [Table 4]

[0132] <Considerations on laminates containing aluminum foil> Comparing the laminates of Examples 1 to 22 shown in Table 4 with the laminates of Comparative Examples 1 to 5, it was found that the laminates of Examples 1 to 22 have resin layers on both sides of an aluminum foil, the resin layers contain one or more additives selected from the group consisting of carboxylic acids, ionic crystals consisting of hydroxide ions, water-soluble polysaccharides and highly water-absorbent polymers, and the additives are contained in the resin layers in an amount of 10% by mass or more and 90% by mass or less, thereby obtaining high evaluation results in evaluation tests 1, 2 and 3.

[0133] From the laminates of Examples 1 to 16 and 19 to 21, it was confirmed that the aluminum foil used in the laminate contains Al, Fe, Ni and Zn in the aluminum foil, and in this case, when the contents of Fe, Ni and Zn in the aluminum foil are [Fe], [Ni] and [Zn], respectively, in mass%, [Zn] is 0.4 or more and 5.1 or less, [Fe] + [Ni] is 0.4 or more and 4.8 or less, and [Fe] + [Ni] + 2 × [Zn] is 2.5 or more.

[0134] <Form of use> The laminate in the present invention is one having a resin layer on both sides of an aluminum foil. For example, its use form is a packaging material in which a resin is laminated on both sides of an aluminum foil. The packaging material is a material used to form a package such as a bag, a tube, a container, or a lid, and its shape and size are not particularly limited. The packaging material is generally in a sheet form, and can be formed into a package by processing such as molding or lamination (heat sealing).

[0135] The laminate of the present invention has a resin layer on both sides of the aluminum foil, thereby protecting the aluminum foil, acquiring strength that is difficult to break, and imparting functions such as heat sealability and adhesion prevention. The laminate of the present invention may also have an adhesive, paper, nonwoven fabric, anchor coat, etc. between the aluminum foil and the resin layer. Furthermore, the laminate of the present invention may also have a printing layer, an OP varnish layer, an adhesive, paper, nonwoven fabric, anchor coat, etc. [Explanation of symbols]

[0136] 1a, 1b, 1c, 1d Aluminum foil 2a, 2b, 2c, 2d: Aluminum matrix 3a, 3c: Second phase particles with a circle equivalent diameter of 0.1 μm or more 4b, 4d: Second phase particles with a circle equivalent diameter of 3.0 μm or more< / cu> < / mg> < / si>

Claims

1. A laminate having a resin layer on both sides of an aluminum foil, the resin layer contains one or more additives selected from the group consisting of carboxylic acids, ionic crystals formed from hydroxide ions, water-soluble polysaccharides, and highly water-absorbent polymers; The additive is contained in the resin layer in an amount of 10% by mass or more and 90% by mass or less.

2. The aluminum foil contains Al, Fe, Ni and Zn, When the contents of Fe, Ni and Zn in the aluminum foil are [Fe], [Ni] and [Zn] in mass%, respectively, [Zn] is 0.4 or more and 5.1 or less, [Fe] + [Ni] is 0.4 or more and 4.8 or less, and 2. The laminate according to claim 1, wherein [Fe] + [Ni] + 2 × [Zn] is 2.5 or more.

3. The laminate according to claim 1, wherein the aluminum foil has a thickness of 5 μm or more and 100 μm or less.

4. The additives are citric acid, tartaric acid, Ca(OH) ２ 2. The laminate according to claim 1, characterized in that the additive is one or more selected from the group consisting of sugar, glucomannan and sodium polyacrylate.

5. The laminate according to claim 1 , wherein the resin layer on at least one surface of the resin layer is formed from two or more different resin layers.

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