阅读说明：本技术 铝合金箔、层叠体、铝合金箔的制造方法及层叠体的制造方法 (Aluminum alloy foil, laminate, method for producing aluminum alloy foil, and method for producing laminate ) 是由 新宫享 大八木光成 于 2020-03-17 设计创作，主要内容包括：铝合金箔(1)是具有第一面(1A)的铝合金箔。铝合金箔(1)包含铝、硅、0.4质量％以上且1.75质量％以下的锰、0.02质量％以上且0.08质量％以下的铁、0.00001质量％以上且0.03质量％以下的锌、0.00001质量％以上且0.02质量％以下的铜、以及0.00001质量％以上且0.01质量％以下的镁。在铝合金箔(1)中,硅和铁的含量的合计为0.1质量％以下。在铝合金箔(1)中,锰的质量相对于硅和铁的合计质量的比率为7.0以上。在第一面(1A)中,当量圆直径为1.5μm以上的第二相粒子的面积率为0.1％以下。电阻率值为3.0μΩcm以上且5.0μΩcm以下。(The aluminum alloy foil (1) is an aluminum alloy foil having a first surface (1A). The aluminum alloy foil (1) contains aluminum, silicon, 0.4 to 1.75 mass% of manganese, 0.02 to 0.08 mass% of iron, 0.00001 to 0.03 mass% of zinc, 0.00001 to 0.02 mass% of copper, and 0.00001 to 0.01 mass% of magnesium. In the aluminum alloy foil (1), the total content of silicon and iron is 0.1 mass% or less. In the aluminum alloy foil (1), the ratio of the mass of manganese to the total mass of silicon and iron is 7.0 or more. The area ratio of the second phase particles having an equivalent circle diameter of 1.5 μm or more on the first surface (1A) is 0.1% or less. The specific resistance value is 3.0 [ mu ] omega cm or more and 5.0 [ mu ] omega cm or less.)

1. An aluminum alloy foil having a first side,

the aluminum alloy foil includes:

aluminum;

silicon;

0.4 to 1.75 mass% of manganese;

0.02 to 0.08 mass% of iron;

0.00001 to 0.03 mass% of zinc;

0.00001 to 0.02 mass% of copper; and

0.00001 to 0.01 mass% of magnesium,

in the aluminum alloy foil, the total content of silicon and iron is 0.1 mass% or less,

in the aluminum alloy foil, the ratio of the mass of manganese to the total mass of silicon and iron is 7.0 or more,

the area ratio of second phase particles having an equivalent circle diameter of 1.5 [ mu ] m or more in the first surface is 0.1% or less,

the specific resistance value is 3.0 [ mu ] omega cm or more and 5.0 [ mu ] omega cm or less.

2. The aluminum alloy foil as set forth in claim 1, wherein the number of the second phase particles per unit area in the first surface is 10/0.01228 mm²The following.

3. The aluminum alloy foil according to claim 2, wherein a material constituting the second phase particles contains at least 1 element selected from the group consisting of silicon, manganese, and iron.

4. The aluminum alloy foil according to claim 3, wherein the content of iron obtained when a solution obtained by dissolving the aluminum alloy foil in phenol is filtered through a filter having an average equivalent circle diameter of 1 μm is 90 ppm by mass or more and 400 ppm by mass or less with respect to the total mass of the aluminum alloy foil before dissolution.

5. The aluminum alloy foil according to any one of claims 1 to 4, wherein a thickness in a direction intersecting the first surface is 5 μm or more and 300 μm or less.

6. A laminate provided with:

an aluminum alloy foil as set forth in any one of claims 1 to 5; and

a first layer disposed on at least one of the first surface and a second surface opposite to the first surface of the aluminum alloy foil,

the total thickness of the aluminum alloy foil and the first layer in the direction intersecting the first surface is 6 [ mu ] m to 301 [ mu ] m.

7. A method for manufacturing an aluminum alloy foil, comprising:

a step of preparing an ingot by melt casting;

a step of cold rolling the ingot at least 1 time to form a cold rolled material; and

a final annealing step of annealing the cold rolled material,

the ingot comprises:

aluminum;

silicon;

0.4 to 1.75 mass% of manganese;

0.02 to 0.08 mass% of iron;

0.00001 to 0.03 mass% of zinc;

0.00001 to 0.02 mass% of copper; and

0.00001 to 0.01 mass% of magnesium,

the total content of silicon and iron is 0.1 mass% or less,

the ratio of the mass of manganese to the total mass of silicon and iron is 7.0 or more,

the area ratio of the second phase particles having an equivalent circle diameter of 1.5 μm or more on the surface of the ingot cold-rolled in the step of forming a cold-rolled material and the area ratio of the second phase particles on the surface of the ingot prepared in the step of preparing are both 0.1% or less.

8. A method for manufacturing a laminate, comprising:

preparing the aluminum alloy foil produced by the method for producing an aluminum alloy foil according to claim 7; and

and a step of forming a first layer on at least one of a first surface and a second surface on the opposite side of the first surface of the aluminum alloy foil.

Technical Field

The present invention relates to an aluminum alloy foil, a laminate, a method for producing an aluminum alloy foil, and a method for producing a laminate.

Background

In recent years, from the viewpoint of reducing environmental load, further weight reduction is desired for aircrafts, railway vehicles, and automobiles used in moving mechanisms. In addition, from the viewpoint of handling, further weight reduction is also desired for various machine parts, electric and electronic related members, building materials, members used in the fields of home use, and the like.

Under such a background, when a metal material is used for these members, the weight of the members is reduced by using aluminum and/or an aluminum alloy having a smaller density, instead of a steel material or copper having a relatively large density.

On the other hand, a typical aluminum alloy is easily corroded if exposed to water, moisture, brine, or the like. Therefore, an aluminum alloy foil having high corrosion resistance against water, moisture, salt water, and the like is proposed in international publication No. 2018/123933. In the aluminum alloy foil disclosed in international publication No. 2018/123933, reduction in weight accompanying corrosion is suppressed.

Documents of the prior art

Patent document

Patent document 1: international publication No. 2018/123933

Disclosure of Invention

Problems to be solved by the invention

When the aluminum alloy foil is used in a high-temperature environment where it is exposed to water, moisture, salt water, or the like, the resistance to moist heat and the corrosion resistance of the surface to salt water (hereinafter referred to as salt water resistance) become particularly problematic. For example, in the building material, from the viewpoint of the appearance, in the electric and electronic related member, from the viewpoint of the surface conductivity, how to reduce the area ratio of the corroded region in the surface of the aluminum alloy foil becomes a problem.

Further, depending on the use of the aluminum alloy foil, high yield strength and high tensile elongation (unit:%) are required for the aluminum alloy foil.

However, conventionally, it has not been known that an aluminum alloy foil which not only satisfies both of moist heat resistance and salt water resistance at high levels but also satisfies both of yield strength and tensile elongation at high levels. The present inventors have found that the present invention is intended to provide an aluminum alloy foil and a laminate which achieve both moisture and heat resistance and brine resistance, as well as yield strength and tensile elongation at high levels.

Means for solving the problems

The aluminum alloy foil of the present invention is an aluminum alloy foil having a first surface. The aluminum alloy foil contains aluminum, silicon, 0.4 to 1.75 mass% of manganese, 0.02 to 0.08 mass% of iron, 0.00001 to 0.03 mass% of zinc, 0.00001 to 0.02 mass% of copper, and 0.00001 to 0.01 mass% of magnesium. In the aluminum alloy foil, the total content of silicon and iron is 0.1 mass% or less. In the aluminum alloy foil, the ratio of the mass of manganese to the total mass of silicon and iron is 7.0 or more. The area ratio of the second phase particles having an equivalent circle diameter of 1.5 μm or more on the first surface is 0.1% or less. The specific resistance value is 3.0 [ mu ] omega cm or more and 5.0 [ mu ] omega cm or less.

Effects of the invention

According to the present invention, an aluminum alloy foil and a laminate having a surface with improved corrosion resistance against salt water can be provided as compared with the aluminum alloy foil described above.

Drawings

Fig. 1 is a schematic cross-sectional view for explaining an aluminum foil according to the present embodiment.

Fig. 2 is a flowchart showing a method for manufacturing an aluminum foil according to the present embodiment.

Fig. 3 is a schematic cross-sectional view showing a laminate according to the present embodiment.

Fig. 4 is a flowchart showing a method for manufacturing a laminate according to the present embodiment.

Fig. 5 is a flowchart showing a modification of the method for manufacturing an aluminum foil according to the present embodiment.

Detailed Description

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following drawings, the same or corresponding portions are denoted by the same reference numerals, and the description thereof will not be repeated.

< constitution of aluminum alloy foil >

First, as shown in fig. 1, an aluminum alloy foil 1 of the present embodiment will be described. The aluminum alloy foil 1 has a first surface 1A and a second surface 1B located on the opposite side of the first surface 1A. The first face 1A and the second face 1B each have, for example, a rectangular shape. The first surface 1A and the second surface 1B of the aluminum alloy foil 1 are surfaces having the largest surface area among surfaces that can be visually confirmed by a microscope or the like in the appearance of the aluminum alloy foil 1. Strictly speaking, the oxide film is formed on the first surface 1A and the second surface 1B of the aluminum alloy foil 1, and the first surface 1A and the second surface 1B of the aluminum alloy foil 1 referred to in the present invention refer to the main surface of the aluminum alloy foil 1 including these oxide films.

The aluminum alloy foil 1 contains aluminum (Al), silicon (Si), manganese (Mn), zinc (Zn), iron (Fe), copper (Cu), and magnesium (Mg). The remaining part of the aluminum alloy foil 1 is composed of impurities. The impurities are, for example, inevitable impurities, but may include a trace amount of impurities which do not greatly affect the salt water resistance and the moist heat resistance, in addition to the inevitable impurities. The impurities include, for example, at least 1 element selected from vanadium (V), titanium (Ti), zirconium (Zr), chromium (Cr), nickel (Ni), boron (B), gallium (Ga), bismuth (Bi), and the like. The aluminum content in the aluminum alloy foil 1 is 98.0 mass% or more. The content of each element contained as the impurity in the aluminum alloy foil 1 is preferably 0.05 mass% or less.

(1) Content of manganese (Mn)

The aluminum alloy foil 1 contains 0.4 mass% to 1.75 mass% of manganese. The manganese in the aluminum alloy foil 1 does not significantly reduce the corrosion resistance of the first surface 1A to salt water (hereinafter referred to as salt water resistance), and improves the strength of the aluminum alloy foil 1. If the content of manganese is less than 0.4 mass%, the strength and surface hardness become insufficient. On the other hand, if the manganese content exceeds 1.75 mass%, the strength of the aluminum alloy foil becomes too strong and the tensile elongation becomes insufficient.

(2) Content of iron (Fe)

The aluminum alloy foil 1 contains 0.02 mass% or more and 0.08 mass% or less of iron. The iron in the aluminum alloy foil 1 improves the corrosion resistance of the first surface 1A in a high-temperature and high-humidity atmosphere. If the iron content is less than 0.02 mass%, the corrosion resistance (hereinafter referred to as wet heat resistance) of the first surface 1A in a high-temperature and high-humidity atmosphere becomes insufficient. On the other hand, if the iron content exceeds 0.08 mass%, the salt water resistance, particularly at-40 to 60 ℃, is significantly reduced as compared with the case where the iron content is 0.08 mass% or less. The iron content obtained when a solution obtained by dissolving an aluminum alloy foil in phenol is filtered through a filter having an average equivalent circle diameter of 1 μm is preferably 90 ppm by mass or more and 400 ppm by mass or less with respect to the total mass of the aluminum alloy foil before dissolution. If the content is within the above range, the moist heat resistance and the salt water resistance can be further improved.

(3) Content of zinc (Zn)

The aluminum alloy foil 1 contains 0.00001 mass% or more and 0.03 mass% or less of zinc. The zinc in the aluminum alloy foil 1 reduces the salt water resistance and the moist heat resistance of the first surface 1A. If the content of zinc exceeds 0.03 mass%, the salt water resistance and the moist heat resistance of the first surface 1A are lower than those in the case where the content of zinc is 0.03 mass% or less. The lower limit of the zinc content is not particularly limited, and is, for example, 0.00001 mass% from the viewpoint of production cost. In order to reduce the zinc content to less than 0.0001 mass%, it is necessary to repeat the triple-layer electrolysis method a plurality of times, and in this case, the production cost significantly increases. The content of zinc is preferably 0.0001% by mass or more.

(4) Copper (Cu) content

The aluminum alloy foil 1 contains 0.00001 mass% to 0.02 mass% of copper. Copper in the aluminum alloy foil 1 reduces the salt water resistance and the moist heat resistance of the first surface 1A. If the copper content exceeds 0.02 mass%, the salt water resistance and the moist heat resistance of the first surface 1A are lowered and the elongation of the aluminum alloy foil 1 is lowered as compared with the case where the copper content is 0.02 mass% or less. The lower limit of the copper content is not particularly limited, and is 0.00001 mass% from the viewpoint of production cost, for example. This is because, in order to reduce the copper content to less than 0.00001 mass%, it is necessary to repeat the fractional crystallization method a plurality of times in addition to the triple-layer electrolysis method, and in this case, the production cost significantly increases. The copper content is preferably 0.0001 mass% or more. The salt water resistance can be improved if the copper content is 0.01 mass% or less, and therefore, the copper content is preferably 0.005 mass% or less.

(5) Content of magnesium (Mg)

The aluminum alloy foil 1 contains 0.00001 mass% to 0.01 mass% of magnesium. Magnesium in the aluminum alloy foil 1 is an element that does not significantly adversely affect the corrosion resistance of the first surface 1A. However, if the content of magnesium exceeds 0.01 mass%, magnesium is concentrated in the oxide film formed on the first surface 1A, and defects are likely to occur in the oxide film. In the case where the aluminum alloy foil 1 and another layer formed on the first surface 1A constitute the laminated body 10, the defect of the oxide film causes delamination at the joint interface of the aluminum alloy foil 1 and the other layer. The upper limit of the magnesium content is preferably 0.005 mass% or less, and more preferably 0.001 mass% or less. The lower limit of the magnesium content is not particularly limited, and is, for example, 0.00001 mass% from the viewpoint of production cost. This is because, in order to reduce the magnesium content to less than 0.00001 mass%, it is necessary to repeat the triple-layer electrolysis method a plurality of times, and in this case, the production cost significantly increases.

(6) Sum of contents of silicon and iron

In the aluminum alloy foil 1, the total content of silicon and iron is 0.1 mass% or less. When the aluminum alloy foil 1 contains silicon, the moist heat resistance of the first surface 1A is improved as compared with the case where the aluminum alloy foil 1 does not contain silicon. That is, silicon and iron in the aluminum alloy foil 1 improve the moist heat resistance of the first surface 1A. On the other hand, the higher the silicon content in the aluminum alloy foil 1, the lower the corrosion resistance under an acidic environment, and pitting corrosion occurs. Further, since the aluminum alloy foil 1 contains silicon, iron, and manganese, the larger the total content of silicon and iron is, the larger the amount of Al — Mn — Fe — Si-based second phase particles is generated in the aluminum alloy foil 1, and the elongation (elongation at break) of the aluminum alloy foil 1 is reduced. The total content of silicon and iron is 0.1 mass% or less from the viewpoints of suppressing pitting corrosion by silicon, suppressing a decrease in salt water resistance by iron, and suppressing a decrease in elongation of the aluminum alloy foil 1 by the Al — Mn — Fe — Si-based second phase particles. The total content of silicon and iron is preferably 0.08 mass% or less.

(7) Ratio of manganese content to total content of silicon and iron

The content of manganese in the aluminum alloy foil 1 was set to M₁Setting the content of silicon as M₂Setting the content of iron as M₃. Ratio M of manganese content to total content of silicon and iron in aluminum alloy foil 1₁/(M₂+M₃) Is 7.0 or more. The present inventors confirmed that even if the aluminum alloy foil 1 satisfies all of the above-described composition, content, and total of the contents of silicon and iron, the ratio M is set to be the above-described ratio₁/(M₂+M₃) If the salt water resistance is less than 7.0, the salt water resistance of the first surface 1A is insufficient (see comparative example 4 described later). The reason is not clear, but if the content of manganese is small relative to the total content of silicon and iron, a large amount of Al-Fe second phase particles or Al-Fe-Si second phase particles are formed in the aluminum alloy foil 1. The electric corrosion current values of the Al-Fe system second phase particles and the Al-Fe-Si system second phase particles are higher than those of the Al-Mn-Fe system second phase particles and the Al-Mn-Fe-Si system second phase particles. Therefore, it is considered that the above ratio M₁/(M₂+M₃) When the ratio is less than 7.0, pitting corrosion is likely to occur on the first surface 1A due to the salt water, and the salt water resistance of the first surface 1A is higher than the ratio M₁/(M₂+M₃) When the salt water resistance is 7.0 or more, the salt water resistance of the first surface 1A is lower than that of the second surface. Preferably the above ratio M₁/(M₂+M₃) Is 8.0 or more.

The above composition of the aluminum alloy foil 1 was measured by inductively coupled plasma emission spectrometry. Examples of the measuring apparatus include iCAP6500DUO manufactured by Thermo Fisher Scientific Co., Ltd, ICPS-8100 manufactured by Shimadzu corporation, and the like.

(8) Resistivity value

The aluminum alloy foil 1 has a resistivity value of 3.0 [ mu ] omega cm or more and 5.0 [ mu ] omega cm or less. The lower the content of each element added to the aluminum alloy foil 1, the lower the resistivity value of the aluminum alloy foil 1. When the specific resistance value of the aluminum alloy foil 1 is less than 3.0. mu. omega. cm, the content of each element added to the aluminum alloy foil 1 is small as compared with the case where the specific resistance value of the aluminum alloy foil 1 is 3.0. mu. omega. cm or more, and the strength of the aluminum alloy foil 1 is low. Further, the higher the solid solution amount of each element in the aluminum mother phase, the higher the resistivity value of the aluminum alloy foil 1. When the resistivity value of the aluminum alloy foil 1 exceeds 5.0 μ Ω cm, the solid solution amount of each element in the aluminum matrix phase is larger and the elongation (elongation at break) of the aluminum alloy foil 1 is lower than that in the case where the resistivity value of the aluminum alloy foil 1 is 5.0 μ Ω cm or less. Aluminum alloy foil 1 satisfying all of the above-described composition, content, total of silicon and iron content, and ratio of manganese content to total of silicon and iron content, and having a specific resistivity value of 3.0 μ Ω cm or more and 5.0 μ Ω cm or less, has moisture and heat resistance, salt water resistance, strength, and elongation at high levels, and is therefore suitable for packaging materials for packaging beverages, foods, medicines, and the like containing salt, building materials such as heat insulating materials and waterproof sheets, members installed in the sea, mechanical parts for ships, aviation, automobiles, railways, and the like, covering materials for moisture prevention or electromagnetic shielding of electric and electronic related members, and decorative materials. In particular, the aluminum alloy foil 1 is suitable for packaging materials and building materials requiring high formability. Further, the aluminum alloy foil 1 is not easily broken even when it is bent, and is therefore suitable for a covering material that covers a cable and exhibits an electromagnetic shielding effect.

The resistivity value was measured by the dc 4 terminal method in accordance with JIS2525(1999 edition).

(9) Area fraction of second phase particles

0.01228mm at the first face 1A²The area ratio of the second phase particles having a circle-equivalent diameter of 1.5 μm or more in the rectangular field of view (128.2 μm. times.95.8 μm) of (2) is 0.1% or less. The present inventors confirmed the following cases: even if the aluminum alloy foil 1 satisfies all of the above-described composition, content, total of the contents of silicon and iron, and ratio of the content of manganese to the total content of silicon and iron,when the area ratio of the second phase particles having a circle-equivalent diameter of 1.5 μm or more exceeds 0.1%, the salt water resistance of the first surface 1A is also insufficient (see comparative examples 1 and 16 described later). The reason is not clear. However, it is known that aluminum alloy foil exhibits an action of inhibiting the progress of pitting by growing aluminum hydrate in the vicinity of the surface to such an extent as to cover the pitting portion while the pitting proceeds. When the area ratio of the second phase particles having a circle-equivalent diameter of 1.5 μm or more exceeds 0.1%, the above-described action is hardly caused, and as a result, the salt water resistance of the first surface 1A is considered to be lowered. The second phase particles include at least one type of second phase particles selected from the group consisting of the Al-Fe system second phase particles, Al-Fe-Si system second phase particles, Al-Mn-Fe system second phase particles, and Al-Mn-Fe-Si system second phase particles. That is, the material constituting the second phase particles contains at least 1 element selected from the group consisting of silicon, manganese, and iron.

(10) Number density of second phase particles

0.01228mm at the first face 1A²In the rectangular field of view (128.2. mu. m.times.95.8. mu.m), the number (hereinafter referred to as the number density) of second-phase particles having a circle-equivalent diameter of 1.5 μm or more per rectangular field of view is 10 particles/0.01228 mm²The following. That is, the number of the second phase particles observed in 1 of the rectangular fields is 10 or less. The number density of second phase particles having an equivalent circle diameter of 1.5 μm or more in the rectangular field of view is preferably less than 4 particles/mm². The present inventors confirmed the following cases: even if the aluminum alloy foil 1 satisfies all of the above-described composition, content, total of contents of silicon and iron, and ratio of content of manganese to total of contents of silicon and iron, the number density of the second phase particles having an equivalent circle diameter of 1.5 μm or more exceeds 10/0.01228 mm²In the case of (2), the salt water resistance of the first surface 1A is also insufficient (see comparative example 17 described later). The number density of the second phase particles having an equivalent circle diameter of 1.5 μm or more exceeds 10/0.01228 mm²In the case of (2), the area ratio of the second phase particles exceeds 0.1%. Therefore, the number density of the second phase particles having an equivalent circle diameter of 1.5 μm or more exceeds 10/0.01228 mm²In the case of (2), it is considered that the aluminum hydrate is hard to be raisedThe effect of inhibiting the progress of pitting corrosion results in a decrease in the salt water resistance of the first surface 1A.

The number density and area ratio of the second phase particles of the aluminum alloy foil 1 were determined by using a Scanning Electron Microscope (SEM) according to a backscattered electron image of 0.01228mm²Is measured in a rectangular field (128.2. mu. m.times.95.8 μm).

(11) Thickness of aluminum alloy foil

The thickness of the aluminum alloy foil 1 in the direction intersecting the first surface 1A is preferably 5 μm or more from the viewpoint of strength and ease of production, and is preferably 300 μm or less from the viewpoint of weight reduction. More preferably, the thickness of the aluminum alloy foil 1 is 5 μm or more and 200 μm or less. The thickness is set to be within the above range by casting and rolling, or by casting, rolling and heat treatment.

(12) Yield strength and elongation at break of aluminum alloy foil

The 0.2% yield strength of the aluminum alloy foil 1 measured by the method in accordance with the tensile test method specified in JIS Z2241 (2011 annual edition) was 100N/mm²The above. The aluminum alloy foil 1 has an elongation at break of 5% or more as measured by a method in accordance with the tensile test method specified in JIS Z2241 (2011 annual version). The test piece in the tensile test was a rectangular parallelepiped, and the thickness was 5 μm or more and 300 μm or less, the length in the rolling direction was 200mm, and the length in the direction perpendicular to the rolling direction was 15 mm. The drawing speed was set to 20 mm/min. The distance between the punctuations (e.g., chuck sections) is set to 100 mm. Examples of the test apparatus include STROGRAPH VES5D manufactured by TOYOBO FINISH MACHINE.

< method for producing aluminum alloy foil >

The method for manufacturing the aluminum alloy foil 1 of the present embodiment includes: the method includes the steps of preparing an ingot (S10), cold rolling the ingot to form a cold rolled material (S20), and annealing the cold rolled material (S30). Fig. 2 is a flowchart showing an example of the method for producing the aluminum alloy foil 1 according to the present embodiment.

First, an ingot is prepared (step S10). Specifically, a melt of aluminum having a predetermined composition is prepared, and the melt of aluminum is solidified and cast to prepare an ingot. The melt is prepared, for example, by adding iron or an aluminum-iron master alloy and manganese or an aluminum-manganese master alloy to a melted aluminum ingot. The casting method is not particularly limited, and may be, for example, semi-continuous casting, or mold casting. The contents of silicon (Si), manganese (Mn), zinc (Zn), iron (Fe), copper (Cu), and magnesium (Mg) in the melt were controlled so that the aluminum alloy foil 1 had the above composition.

Next, the ingot is cold-rolled to form a cold-rolled material (step (S20)). In this step, the ingot prepared in the above step (S10) is cold-rolled without being subjected to the homogenization heat treatment and the hot rolling. The area ratio of the second phase particles on the surface of the ingot cold-rolled in this step and the area ratio of the second phase particles on the surface of the ingot prepared in the preparation step (S10) are both 0.1% or less. In other words, the amount of heat applied to the ingot between the above-described step (S10) and the present step (S20) is smaller than the sum of the amounts of heat applied to the ingot and the hot-rolled material when the homogenization heat treatment and the hot rolling are performed.

The cold rolled material formed in this step (S20) has a second surface. The thickness of the cold rolled material in the direction intersecting the second surface is equal to the thickness of the aluminum alloy foil 1 intersecting the first surface 1A. In other words, after this step (S20), cold rolling is not performed. In this step (S20), cold rolling is performed a plurality of times (for example, 2 times). The cold rolling step to be finally performed in this step is a cold rolling step (hereinafter referred to as a final cold rolling step) to be finally performed in the present manufacturing method.

This step (S20) includes, for example, an intermediate annealing step. For example, first, a first cold rolling step of cold rolling an ingot is performed (S20A). Next, an intermediate annealing step of annealing the intermediate cold rolled material formed in the first cold rolling step is performed (S20B). The conditions of the intermediate annealing may be within the range of normal operating conditions, for example, the annealing temperature is 50 ℃ or more and 600 ℃ or less, and the annealing time is 1 second or more and 20 hours or less. The annealing temperature is preferably 150 ℃ or higher and 550 ℃ or lower. Next, the final cold rolling step is performed on the intermediate cold rolled material subjected to the intermediate annealing (S20C). Thus, the cold rolled material is formed.

Next, an annealing step of annealing the cold-rolled material formed in the cold-rolling step is performed (S30B). This step (S30) is performed after the final cold rolling step. In other words, the annealing performed in the present step (S30) is the final annealing performed at the end of the annealing performed in the present manufacturing method. The conditions of the final annealing are, for example, an annealing temperature of 200 ℃ to 400 ℃ and an annealing time of 1 second to 100 hours. The annealing temperature of the final annealing is preferably 250 ℃ to 400 ℃ and the annealing time is preferably 1 second to 50 hours. In this step, the additive elements dissolved in the aluminum mother phase of the cold rolled material after the final cold rolling are discharged from the mother phase, whereby the tensile elongation of the aluminum alloy foil 1 is improved. In addition, in this step, rolling oil remaining on the surface of the cold rolled material after the final cold rolling is removed, whereby the wettability of the aluminum alloy foil 1 is improved. Thus, the aluminum alloy foil 1 was produced.

< construction of laminate >

Next, as shown in fig. 3, a laminate 10 of the present embodiment will be described. The laminate 10 includes the aluminum alloy foil 1 of the present embodiment and the first layer 11 formed on the first surface 1A of the aluminum alloy foil 1. The material constituting the first layer 11 may be arbitrarily selected depending on the use of the laminate 10.

The first layer 11 includes, for example, a resin film layer. As the resin film used for the resin film layer, a film made of a known resin can be widely used, and is not particularly limited. The material constituting the resin film layer contains, for example, at least 1 selected from the group consisting of polyethylene, polypropylene, polybutylene, polyethylene terephthalate, polyethylene naphthalate, polyvinyl chloride, polyvinylidene chloride, polyvinyl alcohol, ethylene vinyl acetate copolymer, polyamide, polyimide, and vinyl chloride. The thickness of the resin film layer may be appropriately set in consideration of the thickness of the aluminum alloy foil and the thickness of the coating layer to be described later so that the thickness of the laminate falls within the above numerical range.

As a method for bonding the resin film layer and the aluminum alloy foil when laminating the two, a known method can be widely used, and there is no particular limitation. Specifically, there may be mentioned a dry lamination method using a two-component curing adhesive such as a polyester urethane adhesive and a polyester adhesive, a co-extrusion method, an extrusion coating method, an extrusion lamination method, a heat sealing method, a heat lamination method using an anchor coating agent, and the like.

The first layer 11 may be a coating layer formed by coating a coating material on the first surface 1A. The material constituting the coating layer includes, for example, at least 1 selected from inorganic coatings such as titanium oxide, silicon oxide, zirconium oxide, and chromium composition, and resin coatings such as acrylic acid, polycarbonate, silicone resin, and fluororesin. The first layer 11 may be an anodized coating layer, a surface-modified layer formed by plasma treatment or the like, a modified layer formed by acid, alkali, or the like.

In such a laminate 10, the aluminum alloy foil 1 as the base material has both salt water resistance and moist heat resistance at a higher level than those of conventional aluminum alloy foils, and is therefore suitable for members requiring high salt water resistance and high moist heat resistance. For example, the present invention is also suitable for packaging materials including salty drinks, foods, medicines, and the like, building materials such as heat insulators and waterproof sheets, members installed in the sea, machine parts for ships, aviation, automobiles, railways, and the like, and covering materials for moisture prevention or electromagnetic shielding of electric and electronic related members, and decorative materials. The laminate 10 may further include a resin layer formed on the second surface 1B.

As shown in fig. 4, the method for producing the laminate 10 includes a step of producing the aluminum alloy foil 1 by the method for producing the aluminum alloy foil 1 and a step of forming the first layer 11. In other words, the method for manufacturing the laminate 10 includes: the method for manufacturing the first layer 11 includes a step of preparing an ingot (S10), a step of cold-rolling the ingot to form a cold-rolled material (S20), a step of annealing the cold-rolled material (S30), and a step of forming the first layer 11 (S40). In the step of forming the first layer 11 (S40), the first layer 11 is formed on the first surface 1A by an arbitrary method. As described above, for example, the first layer 11 may be formed by bonding a film layer formed in advance to the first surface 1A, or the first layer 11 may be formed by applying a coating material having fluidity to the first surface 1A and curing the coating material.

< modification example >

Fig. 5 is a flowchart showing another example of the method for producing the aluminum alloy foil 1 according to the present embodiment. In the method for manufacturing the aluminum alloy foil 1 shown in fig. 5, for example, cold rolling is performed a plurality of times without interposing an intermediate annealing step in the cold rolling step (S20), and then a final annealing step (S30) is performed. The conditions of the finish annealing are the same as those of the above-described method for producing aluminum alloy foil 1 shown in FIG. 2.

The present inventors have found that an aluminum alloy foil 1 having both moisture-heat resistance and salt water resistance at high levels can be produced by cold rolling an ingot adjusted so that the aluminum alloy foil 1 has the above-described composition without subjecting the ingot to a homogenizing heat treatment or a hot rolling. Further, the present inventors confirmed that the contribution of the final annealing step to the improvement of the tensile elongation of the aluminum alloy foil 1 is higher than that of the intermediate annealing step. That is, it was confirmed that the yield strength and the tensile elongation of the aluminum alloy foil 1 were both high in the aluminum alloy foil 1 manufactured by performing the final annealing step, compared with the aluminum alloy foil 1 manufactured by performing the intermediate annealing step but not performing the final annealing step. It is considered that the final annealing step promotes the discharge of the additive elements dissolved in the aluminum mother phase of the cold rolled material after the final cold rolling step from the mother phase, and as a result, the tensile elongation of the aluminum alloy foil 1 is improved.

In the method for manufacturing the aluminum alloy foil 1 of the present embodiment, the cold rolling may be performed 3 times or more in the step of annealing the cold rolled material (S30). In this case, a plurality of intermediate anneals may be performed. The intermediate annealing step may be performed after the cold rolling is continuously performed a plurality of times, and then the cold rolling may be further performed 1 or more times. After 1 cold rolling, an intermediate annealing step may be performed, and then the cold rolling may be further performed a plurality of times.

In the method of manufacturing the aluminum alloy foil 1 according to the present embodiment, the step of annealing the cold rolled material (S30) in the method of manufacturing the aluminum alloy foil 1 may be performed only as an intermediate annealing step. That is, when the required tensile elongation is achieved without performing the final annealing step, the step of annealing the cold rolled material (S30) may be performed only as the intermediate annealing step.

The method for producing aluminum alloy foil 1 according to the present embodiment may further include, before the cold rolling step, a step of subjecting the ingot to the homogenization heat treatment and a step of hot rolling the ingot subjected to the homogenization heat treatment. In this case, the homogenization heat treatment may be performed under the condition that the area ratio of the second-phase particles on the surface of the ingot after the homogenization heat treatment is 0.1% or less, and for example, the heating temperature is 300 ℃ to 500 ℃ inclusive, and the heating time is 1 hour to 20 hours inclusive. In the method for manufacturing the aluminum alloy foil 1 according to the present embodiment, the step of performing the homogenization heat treatment and the step of performing the hot rolling are preferably not performed.

The laminate 10 of the present embodiment may further include a second layer, not shown, formed on the second surface 1B. The second layer may have the same configuration as the first layer or may have a different configuration from the first layer.

Examples

As described below, samples of the aluminum alloy foils of the examples and comparative examples of the present embodiment were prepared, and their salt water resistance, moist heat resistance, and surface hardness were evaluated.

First, aluminum alloy foils of examples and comparative examples shown in tables 1 and 2 were produced by the following production steps using ingots of aluminum having different compositions.

[ Table 1]

[ Table 2]

The aluminum alloy foils of examples 1 to 10 and comparative examples 1 to 15 and 19 were produced by casting a molten aluminum adjusted to a predetermined composition to produce an aluminum alloy sheet, cold rolling the aluminum alloy sheet, and then final annealing the cold rolled material. The aluminum alloy foils of comparative examples 16 and 17 were manufactured by casting a melt of aluminum adjusted to a predetermined composition to manufacture an aluminum alloy sheet, subjecting the aluminum alloy sheet to a homogenization heat treatment, and then cold rolling and final annealing. The aluminum alloy foil of comparative example 18 was produced by casting a molten aluminum adjusted to a predetermined composition to produce an aluminum alloy sheet, and cold rolling the aluminum alloy sheet.

In examples 1 to 8 and 10 and comparative examples 2 to 15 and 19, aluminum alloy sheets having a thickness of 6mm were prepared by melt casting at a cooling rate of about 100 ℃/sec. Next, the aluminum alloy sheet is cold-rolled a plurality of times. The cold rolling is performed a plurality of times with an intermediate annealing treatment interposed. The intermediate annealing was performed under the conditions that the heating temperature was 350 ℃ and the heating time was 3 hours. Next, the cold rolled material is subjected to final annealing. The final annealing was performed under the conditions that the heating temperature was 300 ℃ and the heating time was 3 hours. Thus, aluminum alloy foils having the compositions and thicknesses shown in tables 1 and 2 were produced. That is, examples 1 to 8 were produced by the same production method as comparative examples 2 to 15, and examples 1 to 8 were different from comparative examples 2 to 15 only in the composition.

In example 9 and comparative example 1, first, an aluminum alloy sheet having a thickness of 15mm was prepared by melt casting with a cooling rate of 1 ℃/sec or more and 5 ℃/sec or less. Next, the aluminum alloy sheet is cold-rolled a plurality of times. The cold rolling is performed a plurality of times with an intermediate annealing treatment interposed. The intermediate annealing was performed under the conditions that the heating temperature was 350 ℃ and the heating time was 3 hours. Next, the cold rolled material is subjected to final annealing. The final annealing was performed under the conditions that the heating temperature was 300 ℃ and the heating time was 3 hours. Thus, aluminum alloy foils having the compositions and thicknesses shown in tables 1 and 2 were produced.

In comparative example 16, an aluminum alloy sheet having a thickness of 15mm was prepared by melt casting with a cooling rate of 1 ℃/sec or more and 5 ℃/sec or less. Next, the aluminum alloy sheet is subjected to a homogenizing heat treatment. The homogenizing heat treatment was performed at a heating temperature of 550 ℃ for a heating time of 10 hours. Next, the aluminum alloy sheet is cold-rolled a plurality of times. The cold rolling is performed a plurality of times with an intermediate annealing treatment interposed. The intermediate annealing was performed under the conditions that the heating temperature was 350 ℃ and the heating time was 3 hours. Next, the cold rolled material is subjected to final annealing. The final annealing was performed under the conditions that the heating temperature was 300 ℃ and the heating time was 3 hours. Thus, aluminum alloy foils having the compositions and thicknesses shown in Table 2 were produced.

In comparative example 17, an aluminum alloy sheet having a thickness of 6mm was prepared by melt casting with a cooling rate of about 100 ℃/sec. Next, the aluminum alloy sheet was subjected to the homogenizing heat treatment in the same manner as in comparative example 16. The homogenizing heat treatment was performed at a heating temperature of 550 ℃ for a heating time of 10 hours. Next, the aluminum alloy sheet is cold-rolled a plurality of times. The cold rolling is performed a plurality of times with an intermediate annealing treatment interposed. The intermediate annealing was performed under the conditions that the heating temperature was 350 ℃ and the heating time was 3 hours. Next, the cold rolled material is subjected to final annealing. The final annealing was performed under the conditions that the heating temperature was 300 ℃ and the heating time was 3 hours. Thus, aluminum alloy foils having the compositions and thicknesses shown in Table 2 were produced.

In comparative example 18, an aluminum alloy sheet having a thickness of 6mm was prepared by melt casting at a cooling rate of about 100 ℃/sec. Subsequently, the aluminum alloy sheet was cold-rolled a plurality of times to produce aluminum alloy foils having the compositions and thicknesses shown in table 2. In comparative example 18, the final annealing step was not performed.

In examples 1 to 10 and comparative examples 1 to 19, the cold rolling conditions were adjusted so that the surface roughness Ra of each of the finally obtained aluminum alloy foils in the directions parallel and perpendicular to the rolling direction became 0.2 μm or less. The surface roughness Ra is a center line average roughness Ra specified in JIS B0601 (1982).

The compositions shown in tables 1 and 2 were determined as follows: a test piece of 1.00g obtained from each of the aluminum alloy foils produced as described above was measured using an inductively coupled plasma emission spectrometer (ICPS-8100, Shimadzu corporation).

Each sample thus prepared was evaluated by the following evaluation method. The evaluation results are shown in tables 1 to 4. The surface evaluated in each sample was a surface having a center line average roughness Ra of 0.2 μm or less.

< evaluation method >

(1) Number density and area fraction of second phase particles

In the measurement of the number density and area ratio of the second phase particles on the surface of each aluminum alloy foil, a backscattered electron image obtained by observing the surface having the center line average roughness Ra of 0.2 μm or less with a Scanning Electron Microscope (SEM) was used. Specifically, first, a backscattered electron image of the surface of each sample is observed in 5 rectangular fields selected at random. Each rectangular field of view is set to 0.01228mm²Rectangular field of view (128.2 μm × 95.8 μm). The backscattered electron image of each rectangular field of view was binarized by image processing software WinRoof2018 manufactured by mitsubishi corporation, and second phase particles having an equivalent circle diameter of 1.5 μm or more were extracted. Regarding the observation conditions of the backscattered electron image, the brightness, contrast, and voltage current value of the electron beam are set so that elements other than the second phase particles such as rolling streaks and oil pits present in the rectangular field image converge in the range of 0 to 70 to 130 by luminance extraction by the lookup table conversion before the binarization processing. The extraction by the binarization processing is specifically performed by the following method. First, in order to remove elements other than the second phase particles such as rolling streaks and oil pits present in the obtained rectangular field image, luminance extraction by lookup table conversion is performed while the upper limit value is fixed to 255 and the lower limit value is adjusted to 70 to 130. Next, after binarization processing based on a single threshold value was performed under a condition that the threshold value was 1.0, particles having an equivalent circle diameter of less than 1.5 μm were deleted from the extracted particles. The number density and area ratio in the plane were calculated for the second phase particles having the equivalent circle diameter of 1.5 μm or more thus extracted.

(2) Resistivity value

The resistivity value of each aluminum alloy foil was measured by the dc 4 terminal method in accordance with JIS2525(1999 edition). The measurement instrument used was 3541RESISTANCE HITESTER manufactured by HIOKI, and the measurement terminal used was 9770 manufactured by HIOKI. The test piece was a rectangular parallelepiped, and the thickness was 5 μm or more and 300 μm or less, the length in the rolling direction was 200mm, and the length in the direction perpendicular to the rolling direction was 15 mm. The distance between the measurement terminals was set to 115mm, and the resistivity value was calculated from the resistance value obtained in the measurement.

(3) Evaluation test of Wet Heat resistance

The moist heat resistance evaluation test was performed as follows: test pieces of 40mm × 40mm cut out from each aluminum alloy foil were evaluated, and each test piece was allowed to stand for 12 hours in a high-temperature high-humidity atmosphere at a temperature of 120 ℃ and a humidity of 100% by applying a pressure higher than atmospheric pressure. The increase in weight after the test relative to the weight before the test was measured, and the wet heat resistance was evaluated from the increase in weight due to oxidation corrosion of the surface under the high-temperature and high-humidity atmosphere.

(4) Evaluation test of salt Water resistance

The salt water resistance evaluation test was carried out under the test conditions of the neutral salt spray test specified in JIS Z2371, with test pieces of 15mm × 10mm cut out from each aluminum alloy foil as evaluation targets. The spraying time was set to 48 hours. Next, a backscattered electron image of the surface of each sample was observed in 5 rectangular fields selected at random. Each rectangular field of view is set to 0.01228mm²Rectangular field of view (128.2 μm × 95.8 μm). The backscattered electron image of each rectangular field of view was binarized by image processing software WinRoof2018 manufactured by mitsubishi corporation, and a corrosion (pitting) generating portion having an equivalent circle diameter of 1.0 μm or more was extracted. Regarding the observation conditions of the backscattered electron image, the brightness, contrast, and voltage/current value of the electron beam are set so that elements other than corrosion (pitting) generating portions such as rolling streaks and oil pits present in the rectangular field image converge in a range of 70 to 130 and 255 through luminance extraction by lookup table conversion before binarization processing. The extraction by the binarization processing is specifically performed by the following method. First, in order to remove elements other than corrosion (pitting) generating portions such as rolling streaks and oil pits present in the obtained rectangular field image, luminance extraction by lookup table conversion is performed while fixing the lower limit value to 0 and adjusting the upper limit value to 70 to 130. Next, after binarization processing based on a single threshold value is performed under the condition of the threshold value 254, the extracted corrosion (pitting corrosion) occursThe corrosion (pitting) generating portion having an equivalent circle diameter of less than 1.0 μm was partially deleted. The area ratio of the corrosion (pitting) generating portion having the equivalent circle diameter of 1.0 μm or more thus extracted was calculated, and the average of the calculation results obtained from 5 rectangular fields of view was used as the evaluation result.

(5) Yield strength and tensile elongation

The 0.2% yield strength and tensile elongation of each aluminum alloy foil were measured using STROGRAPH VES5D manufactured by Toyo Seiki Seisaku-Sho. The tensile test was carried out by a method in accordance with the tensile test method prescribed in JIS Z2241 (2011 annual edition). The test piece in the tensile test was a rectangular parallelepiped, and the above thickness was 5 μm or more and 300 μm or less, the length in the rolling direction was 200mm, and the length in the direction perpendicular to the rolling direction was 15 mm. The drawing speed was set to 20 mm/min. The distance between the punctuations (e.g., chuck sections) is set to 100 mm. The test apparatus used was STROGRAPH VES5D manufactured by Toyo Seiki Seisaku-sho.

(6) Iron content in second phase particles filtered with a 1 μm filter

0.1g of each aluminum alloy foil was sampled and dissolved in phenol. The resulting solution was filtered through a filter having an average equivalent circle diameter of 1 μm to capture the second phase particles. The captured second phase particles are dissolved with an acid and a base. The acid used was a 75 vol% hydrochloric acid solution and a 25 vol% nitric acid solution, and the base used was a 5 vol% aqueous sodium hydroxide solution. The mass of iron in the obtained solution was measured using an inductively coupled plasma emission spectrometer (ICPS-8100, Shimadzu corporation). The iron content in the second phase particles was determined as a value obtained by dividing the mass of iron in the second phase particles by the total mass of the aluminum alloy foil sample after dissolution.

The evaluation results are shown in tables 3, 4, 5 and 6.

[ Table 3]

[ Table 4]

[ Table 5]

[ Table 6]

< evaluation result >

The present inventors have conducted the above-described evaluation test of salt water resistance of the aluminum alloy foil of international publication No. 2018/123933, and have confirmed that the area ratio of pitting corrosion occurring portion is 1.5% or more. The present inventors have conducted extensive studies and found that the aluminum alloy foils of examples 1 to 10 have higher salt water resistance than the aluminum alloy foil of international publication No. 2018/123933 and have moist heat resistance comparable to the aluminum alloy foil of international publication No. 2018/123933. The present inventors have confirmed that the yield strength and tensile elongation of the aluminum alloy foils of examples 1 to 10 satisfy the respective specifications of yield strength and tensile elongation required for the above-described various applications. That is, the aluminum alloy foils of examples 1 to 10 had high levels of moisture and heat resistance, salt water resistance, yield strength and tensile elongation at the same time.

Each of the aluminum alloy foils of examples 1 to 10 contains aluminum, silicon, 0.4 mass% or more and 1.75 mass% or less of manganese, 0.02 mass% or more and 0.08 mass% or less of iron, 0.00001 mass% or more and 0.03 mass% or less of zinc, 0.00001 mass% or more and 0.02 mass% or less of copper, and 0.00001 mass% or more and 0.01 mass% or less of magnesium. In each of the aluminum alloy foils of examples 1 to 9, the total content of silicon and iron was 0.1 mass% or less, and the ratio of the mass of manganese to the total mass of silicon and iron was 7.0 or more. In each of the aluminum alloy foils of examples 1 to 9, the area ratio of the second phase particles having an equivalent circle diameter of 1.5 μm or more was 1% or less, and the second phase particlesHas a number density of 10/0.01228 mm²And a specific resistance value of 3.0 [ mu ] omega cm or more and 5.0 [ mu ] omega cm or less. In each of the aluminum alloy foils of examples 1 to 9, the weight gain in the evaluation test of the moist Heat resistance was 0.4g/mm²The area ratio of the pitting corrosion occurring portion in the salt water resistance evaluation test was 1.0% or less, and the 0.2% yield strength in the tensile test was 100N/mm²The tensile elongation is 5.0% or more.

In contrast, in the aluminum alloy foils of comparative examples 1 to 19, at least any one of the composition, the total content of silicon and iron, the ratio of the total mass of silicon and iron to the mass of manganese, the area ratio of the second phase particles, and the resistivity value deviates from the above numerical range. In the aluminum alloy foils of comparative examples 1 to 19, at least one of the weight gain in the wet heat resistance evaluation test, the area ratio of the pitting corrosion occurred portion in the salt water resistance evaluation test, and the 0.2% proof stress and tensile elongation in the tensile test was inferior to the aluminum alloy foils of examples 1 to 10. In particular, in the aluminum alloy foils of comparative examples 3, 5, 6, 13, and 15 in which the iron content was more than 0.08 mass%, the area ratio of the pitting corrosion occurring portion in the salt water resistance evaluation test exceeded 1.0%. In addition, in the aluminum alloy foil of comparative example 14 in which the iron content was less than 0.03 mass%, the weight gain in the evaluation test of moist heat resistance exceeded 0.4g/mm²。

In comparative examples 1 to 15 and 19, which were produced by the same production method as in examples 1 to 10 but have different compositions from them, for example, in comparative examples 3 to 6, the ratio of the mass of manganese to the total mass of silicon and iron was less than 7.0, and the area ratio of the pitting corrosion occurring portion in the evaluation test of the brine resistance was more than 1.0%. In comparative example 3, the content of manganese was less than 0.4 mass%, and the total content of silicon and iron exceeded 0.1 mass%. In comparative example 4, the content of manganese and the total content of silicon and iron were within the respective numerical ranges described above. In comparative examples 5 and 6, the content of manganese was within the above numerical range, but the total content of silicon and iron exceeded 0.1 mass%. In comparative examples 3 to 6 in which the ratio is less than 7.0, the Al-Fe-based second phase particles or Al-Fe-Si-based second phase particles are formed in a larger amount than in the aluminum alloy foil in which the ratio is 7.0 or more, and thus it is considered that pitting corrosion is likely to occur due to the salt water.

In comparative examples 16 and 17 in which the ingot before cold rolling was subjected to the homogenization heat treatment, the area ratio of the second phase particles exceeded 0.1%, and the area ratio of the pitting corrosion occurring portion in the salt water resistance evaluation test exceeded 1.0%. In comparative examples 16 and 17, the ratio of the total mass of silicon and iron to the mass of manganese was within the above numerical range. In comparative examples 16 and 17, it is considered that since sufficient heat for growing the second phase particles is applied before cold rolling, a large amount of Al — Fe-based second phase particles or Al — Fe — Si-based second phase particles are formed, and pitting corrosion is likely to occur due to the salt water.

In comparative example 18, which is different from example 1 only in that the final annealing step was not performed after the cold rolling, only the resistivity value and the tensile elongation were inferior to example 1. In comparative example 18, the final annealing step was not performed, and the additive elements dissolved in the aluminum matrix phase were not sufficiently discharged from the matrix phase, and therefore, it is considered that the tensile elongation was lower than that of example 1.

The embodiments and examples disclosed herein are to be considered in all respects as illustrative and not restrictive. The scope of the present invention is shown not by the above embodiments and examples but by the claims, and is intended to include meanings equivalent to the claims and all modifications and variations within the scope.

Description of the reference numerals

1A: first surface, 1B: second surface, 10: laminate, 11: a first layer.