Aluminum foil material and preparation method thereof

Abstract

To provide an aluminum foil material and a preparation method thereof.SOLUTION: The aluminum foil material comprises, based on the total weight of the aluminum foil material, 1.0 wt.% to 2.0 wt.% of Fe, 0.9 wt.% to 1.8 wt.% of Si, 0 wt.% to 0.05 wt.% of Cu, 0 wt.% to 0.05 wt.% of Mn, 0 wt.% to 0.05 wt.% of Mg, 0 wt.% to 0.03 wt.% of Cr, 0 wt.% to 0.05 wt.% of Ti, and the balance of Al, wherein the weight ratio of Fe to Si is in the range of 1.0 to 2.2.EFFECT: By controlling the mass percentage of Fe and Si in the aluminum foil material, the ratio of Fe to Si, and the content of trace elements prone to segregation, particle-induced nucleation particles that contribute to grain refinement can be formed. Furthermore, by controlling the content of Cr, the grain size can be controlled, and microscopic segregation during rapid solidification can be reduced. As a result, the mechanical properties, formability, and surface quality of the aluminum foil material are improved, and the occurrence of pinholes is reduced.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to the technical field of aluminum foil materials, and specifically, to aluminum foil materials and their manufacturing methods.

Background Art

[0002] The aluminum foil material used for aluminum-plastic films has a thickness of 35 to 55 μm and is usually manufactured by the ingot hot rolling method. In the ingot hot rolling method, first, the hot rolling billet is machined by milling to remove defects such as the oxide layer and impurities on the surface of the ingot. Next, the fine structure of the ingot is made more uniform by homogenization. After that, it is necessary to go through a plurality of processes such as hot rolling, cold rolling, and intermediate annealing. As a result of performing recovery and recrystallization many times, the uniformity of the internal structure of the billet and the grain size have been significantly improved. Therefore, hot rolling billets are usually of good quality and suitable for high-quality aluminum foil materials and aluminum foil material products for high-precision processing. However, during the deep drawing process, the hot rolling billet has problems such as a high ear rate, being prone to cracking, and the deformation area not being smooth. This has restricted the improvement of the yield of high-quality aluminum foil materials. In addition, the quality of the hot rolling ingot directly affects the forming quality of the aluminum foil material. From the latter half of 2021 to the present, the supply of hot rolling billets has been tight, the supply sources are limited, and there are problems such as unstable quality, a long processing process, high processing costs, and many surface defects occurring.

[0003] The manufacturing process of aluminum foil material billets by the twin-roll casting and rolling method is relatively simple and low-cost compared with the ingot hot rolling method. It is not necessary to go through complex process steps such as ingot melting, slicing, homogenization, and hot rolling. Instead, the molten aluminum is directly injected into two rotating casting rolls (crystallization devices). In the casting and rolling area, the two processes of solidification and hot rolling are simultaneously completed within 2 to 3 seconds to obtain a slab with a thickness of 4 to 10 mm. After that, through a series of processes such as cold rolling and intermediate annealing, it is finally made into a slab with a thickness of 0.3 to 0.7 mm to obtain the billets of aluminum foil materials. However, depending on the cooling method and hot working conditions during the manufacture of slabs by the twin-roll casting and rolling method, there are defects in the internal microstructure of the casting and rolling slabs, such as segregation, non-uniform structure, and coarse crystal grains after annealing. Furthermore, when macroscopic segregation occurs in the casting and rolling billets, pinholes are likely to occur during rolling, resulting in a decrease in surface quality. Since the twin-roll casting and rolling method is difficult to control quality, it is relatively less used for high-quality aluminum foil material products.

[0004] The aluminum foil materials for high-end lithium battery aluminum plastic film soft packaging in China mainly use 8-series aluminum alloys such as 8021 and 8079, and are all manufactured by ingot hot rolling. However, if the problems such as composition segregation, non-uniformity of the structure, and coarsening of crystal grains caused by the casting and rolling method can be solved, it will be possible to reduce the processing cost of aluminum foil materials and improve the quality of aluminum foil materials.

Summary of the Invention

Problems to be Solved by the Invention

[0005] An object of the present disclosure is to provide an aluminum foil material and a manufacturing method thereof in order to solve the technical problems existing in the prior art that the surface quality, mechanical properties, and formability of aluminum foil materials are poor.

Means for Solving the Problems

[0006] To achieve the above object, according to one aspect of the present disclosure, based on the total weight of the aluminum foil material, the aluminum foil material contains 1.0 wt% to 2.0 wt% of Fe, 0.9 wt% to 1.8 wt% of Si, 0 wt% to 0.05 wt% of Cu, 0 wt% to 0.05 wt% of Mn, 0 wt% to 0.05 wt% of Mg, 0 wt% to 0.03 wt% of Cr, 0 wt% to 0.05 wt% of Ti, and the balance of Al, and the weight ratio of Fe to Si is within the range of 1.0 to 2.2, and an aluminum foil material is provided.

[0007] Furthermore, based on the total weight of the aluminum foil material, the aluminum foil material contains 1.1 wt% to 1.7 wt% of Fe, 1.1 wt% to 1.7 wt% of Si, 0.001 wt% to 0.04 wt% of Cu, 0.001 wt% to 0.04 wt% of Mn, 0.001 wt% to 0.04 wt% of Mg, 0.0001 wt% to 0.03 wt% of Cr, 0.001 wt% to 0.04 wt% of Ti, and the balance of Al.

[0008] Furthermore, based on the total weight of the aluminum foil material, the aluminum foil material contains 1.2 wt% to 1.5 wt% of Fe, 1.1 wt% to 1.5 wt% of Si, 0.001 wt% to 0.04 wt% of Cu, 0.001 wt% to 0.04 wt% of Mn, 0.001 wt% to 0.04 wt% of Mg, 0.0005 wt% to 0.02 wt% of Cr, 0.001 wt% to 0.04 wt% of Ti, and the balance of Al.

[0009] Furthermore, the weight ratio of Fe to Si is within the range of 1.1 to 1.5. Furthermore, the weight ratio of Fe to Si is within the range of 1.1 to 1.3.

[0010] According to another aspect of the present disclosure, there is provided a method for manufacturing the aluminum foil material described above of the present invention, comprising: step S1 of adding raw materials to a melting furnace to melt the raw materials to obtain a molten alloy; step S2 of refining crystal grains of the molten alloy, degassing and filtering, and then performing casting and rolling on a casting and rolling slab; step S3 of cold rolling the casting and rolling slab into a cold-rolled billet; step S4 of subjecting the cold-rolled billet to homogenization treatment at a temperature of 520 to 620 °C to obtain a homogenized cold-rolled billet; step S5 of cold rolling the homogenized cold-rolled billet to obtain a foil-rolled billet; step S6 of rolling the foil-rolled billet into an aluminum foil; and step S7 of annealing the aluminum foil at a temperature of 200 to 340 °C to obtain an aluminum foil material.

[0011] Furthermore, in step S2, the thickness of the casting and rolling slab is 6.0 mm to 10.0 mm. Furthermore, in step S3, the thickness of the cold-rolled billet is 2.0 mm to 5.0 mm. Furthermore, in step S5, the thickness of the foil-rolled billet is 0.2 mm to 1.5 mm. Furthermore, in step S6, the thickness of the aluminum foil is 0.015 mm to 0.06 mm.

Advantages of the Invention

[0012] According to the technical solution of the present disclosure, an aluminum foil material and a manufacturing method thereof are provided. By controlling the mass percentages of Fe and Si in the aluminum foil material, the ratio between the two, and the content of trace elements that are likely to cause segregation, particle-induced nucleation sites that contribute to the refinement of crystal grains can be formed, thereby controlling the crystal grain size, reducing microsegregation during rapid solidification, improving the mechanical properties, formability, and surface quality of the aluminum foil material, and reducing the occurrence of pinholes. Furthermore, the content of Cr element needs to be within a reasonable range. If the content of Cr element is too low, it is likely to cause the cost of refining to increase. If there is too much Cr element, it is likely to precipitate in the form of Al7(CrFe) nano-phase from the matrix, preventing the nucleation of recrystallization. Therefore, it is preferable that the content of Cr element does not exceed 0.03%. If it is outside that range, it is difficult to form recrystallization nuclei, the recrystallized grains become coarser, affecting the formability and surface quality of the aluminum foil. By restricting the content of Cr element, the inhibitory effect of Cr on recrystallization nucleation is reduced.

Brief Description of the Drawings

[0013]

Figure 1

Figure 2

Modes for Carrying Out the Invention

[0014] Unless there is a contradiction, the features in the embodiments and examples of the present application can be combined with each other. Hereinafter, the present invention will be described in more detail with reference to the examples.

[0015] In view of the drawbacks existing in the prior art described in the Background Art, one specific embodiment of the present disclosure provides an aluminum foil material. Based on the total weight of the aluminum foil material, the aluminum foil material contains 1.0 wt% to 2.0 wt% of Fe, 0.9 wt% to 1.8 wt% of Si, 0 wt% to 0.05 wt% of Cu, 0 wt% to 0.05 wt% of Mn, 0 wt% to 0.05 wt% of Mg, 0 wt% to 0.03 wt% of Cr, 0 wt% to 0.05 wt% of Ti, and the balance of Al, and the weight ratio of Fe to Si is within the range of 1.0 to 2.2.

[0016] According to the technical solution of the present disclosure, by controlling the mass percentages of Fe and Si in the aluminum foil material, the ratio between the two, and the content of trace elements that are likely to cause segregation, particle-induced nucleation sites that contribute to the refinement of crystal grains can be formed. Also, by controlling the content of Cr element that inhibits the generation of recrystallization nuclei, the crystal grain size can be controlled, the microsegregation during rapid solidification can be reduced, the mechanical properties, formability, and surface quality of the aluminum foil material can be improved, and the occurrence of pinholes can be reduced.

[0017] For example, based on the total weight of the aluminum foil material, the aluminum foil material may contain 1.0 wt%, 1.1 wt%, 1.2 wt%, 1.3 wt%, 1.4 wt%, 1.5 wt%, 1.6 wt%, 1.7 wt%, 1.8 wt%, 1.9 wt%, or 2.0 wt% of Fe, 0.9 wt%, 1.0 wt%, 1.1 wt%, 1.2 wt%, 1.3 wt%, 1.4 wt%, 1.5 wt%, 1.6 wt%, 1.7 wt%, or 1.8 wt% of Si, 0 wt%, 0.001 wt%, 0.002 wt%, 0.003 wt%, 0.004 wt%, 0.005 wt%, 0.006 wt%, 0.007 wt%, 0.008 wt%, 0.009 wt%, 0.01 wt%, 0.02 wt%, 0.03 wt%, 0.04 wt%, or 0.05 wt% of Cu, 0 wt%, 0.001 wt%, 0.002 wt%, 0.003 wt%, 0.004 wt%, 0.005 wt%, 0.006 wt%, 0.007 wt%, 0.008 wt%, 0.009 wt%, 0.01 wt%, 0.02 wt%, 0.03 wt%, 0.04 wt%, or 0.05 wt% of Mn, 0 wt%, 0.001 wt%, 0.002 wt%, 0.003 wt%, 0.004 wt%, 0.005 wt%, 0.006 wt%, 0.007 wt%, 0.008 wt%, 0.009 wt%, 0.01 wt%, 0.02 wt%, 0.03 wt% of Cr, and 0 wt%, 0.001 wt%, 0.002 wt%, 0.003 wt%, 0.004 wt%, 0.005 wt%, 0.006 wt%, 0.007 wt%, 0.008 wt%, 0.009 wt%, 0.01 wt%, 0.02 wt%, 0.03 wt%, 0.04 wt%, or 0.05 wt% of Ti.

[0018] For example, the weight ratio of Fe to Si may be 1.0, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2.0, 2.1, or 2.2.

[0019] In some examples, based on the total weight of the aluminum foil material, the aluminum foil material contains 1.1 wt% - 1.7 wt% of Fe, 1.1 wt% - 1.7 wt% of Si, 0.001 wt% - 0.04 wt% of Cu, 0.001 wt% - 0.04 wt% of Mn, 0.001 wt% - 0.04 wt% of Mg, 0.0001 wt% - 0.03 wt% of Cr, 0.001 wt% - 0.04 wt% of Ti, and the balance of Al. By controlling each composition of the aluminum foil material within this range, the mechanical properties, formability, and surface quality of the aluminum foil material can be further improved.

[0020] In some examples, based on the total weight of the aluminum foil material, the aluminum foil material contains 1.2 wt% - 1.5 wt% of Fe, 1.1 wt% - 1.5 wt% of Si, 0.001 wt% - 0.04 wt% of Cu, 0.001 wt% - 0.04 wt% of Mn, 0.001 wt% - 0.04 wt% of Mg, 0.0005 wt% - 0.02 wt% of Cr, 0.001 wt% - 0.04 wt% of Ti, and the balance of Al. By controlling each composition of the aluminum foil material within this range, the mechanical properties, formability, and surface quality of the aluminum foil material can be further improved.

[0021] In some examples, the weight ratio of Fe to Si is in the range of 1.1 - 1.5. By controlling the weight ratio of Fe to Si within this range, the mechanical properties, formability, and surface quality of the aluminum foil material can be further improved.

[0022] In some examples, the weight ratio of Fe to Si is in the range of 1.1 - 1.3. By controlling the weight ratio of Fe to Si within this range, the mechanical properties, formability, and surface quality of the aluminum foil material can be further improved.

[0023] According to another embodiment of the present specification, there is provided a method for manufacturing an aluminum foil material of the present invention, including: step S1 of adding a raw material to a smelting furnace to melt the raw material to obtain a molten alloy; step S2 of refining crystal grains of the molten alloy, degassing and filtering, and then casting and rolling into a cast-rolled slab; step S3 of cold rolling the cast-rolled slab into a cold-rolled billet; step S4 of homogenizing the cold-rolled billet at a temperature of 520-620 °C to obtain a homogenized cold-rolled billet; step S5 of cold rolling the homogenized cold-rolled billet to obtain a foil-rolled billet; step S6 of rolling the foil-rolled billet into an aluminum foil; and step S7 of annealing the aluminum foil at a temperature of 200-340 °C to obtain an aluminum foil material.

[0024] According to the technical solution of the present disclosure, by controlling the contents of Fe and Si added to aluminum, the ratio value, and the contents of trace elements that are likely to cause segregation, and combining with processes such as homogenization treatment and rolling deformation, effective particle-induced nucleation sites that contribute to the refinement of crystal grains are formed. Also, by controlling the content of Cr element that inhibits the generation of recrystallization nuclei, the crystal grain size can be controlled, the mechanical properties, formability, and surface quality of the aluminum foil material can be improved, and the occurrence of pinholes can be reduced.

[0025] For example, the homogenization treatment temperature in step S4 may be 520 °C, 530 °C, 540 °C, 550 °C, 560 °C, 570 °C, 580 °C, 590 °C, 600 °C, 610 °C, or 620 °C, and the holding time may be 5 hours or more. Performing the homogenization treatment within this temperature and holding time range is advantageous for the homogenization of the distribution of the metal structure, thereby improving the formability.

[0026] For example, the annealing temperature in step S7 may be 200°C, 210°C, 220°C, 230°C, 240°C, 250°C, 260°C, 270°C, 280°C, 290°C, 300°C, 310°C, 320°C, 330°C, or 340°C, and the heat preservation time may be 2 hours or more. Annealing within the range of temperature and holding time contributes to the formation of recrystallization nucleus generation sites, thereby controlling the crystal grain size and improving the surface quality of the aluminum foil material.

[0027] For example, in the annealing of step S7, the heating rate may be 20°C / hour or more.

[0028] In some examples, in step S2, the thickness of the cast-rolled slab is 6.0 mm to 10.0 mm. At a thickness within this range, not only can the cold rolling deformation amount, strength, and toughness of the subsequent processed billet be better ensured, but also an appropriate degree of supercooling can be more reliably achieved during the cast-rolling process to ensure uniform solidification of the cast-rolled slab.

[0029] In some examples, in step S3, the thickness of the cold-rolled billet is 2.0 mm to 5.0 mm. At a thickness within this range, it is possible to more reliably ensure the energy storage of processing deformation and sufficient crushing of the eutectic phase during the solidification process, provide preparation for the fine structure for subsequent heat treatment, contribute to obtaining advantages such as better surface quality and mechanical properties, and further reduce costs.

[0030] In some examples, in step S5, the thickness of the foil-rolled billet is 0.2 mm to 1.5 mm. Billets with a thickness within this range are very suitable for the production of thin products such as various aluminum foils and packaging films. Compared with thick billets, thin billets can use raw materials more efficiently, reduce waste, and cut costs. Also, billets with a thickness within this range are easier to perform foil rolling processing and can obtain better surface quality and mechanical properties.

[0031] In some examples, in step S6, the thickness of the aluminum foil is 0.015 mm to 0.06 mm. When the thickness is within this range, the use characteristics of the aluminum foil can be ensured better. Furthermore, the aluminum foil with a thickness in this range has important applications in areas such as new energy lithium batteries, food packaging, pharmaceutical packaging, cosmetic packaging, tobacco packaging, electronic products, and building materials.

[0032] Hereinafter, the present application will be described in more detail with reference to specific examples, but these examples should not be construed as limiting the scope of protection claimed by the present application.

[0033] Examples Manufacture of aluminum foil materials for Examples 1 - 8 and Comparative Examples 1 - 3 The composition and its content of aluminum foil materials A - K are shown in Table 1, and the blending of raw materials was carried out according to the composition and content of each aluminum foil material shown in Table 1. Step S1: Put the raw materials blended above into a melting furnace, raise the temperature to melt the raw materials, stir during melting to uniformly mix the liquid materials in the furnace, and obtain a molten alloy. Step S2: Carry out online grain refinement, degassing, and filtration on the molten alloy, and then carry out casting rolling in a twin - roll crystallization device to obtain a casting - rolled slab with a thickness of 6.7 mm. Step S3: Process the casting - rolled slab obtained in Step S2 with a cold rolling mill into a cold - rolled billet with a thickness of 3.0 mm. Step S4: Carry out homogenization treatment on the cold - rolled billet obtained in Step S3 at a temperature of 580 °C and keep it warm for 10 hours to obtain a homogenized cold - rolled billet. Step S5: Cool the homogenized cold - rolled billet obtained in Step S4 to room temperature, and then carry out cold rolling to obtain a foil - rolled billet with a thickness of 0.3 mm. Step S6: Stack - roll the foil - rolled billet with an aluminum foil material rolling mill to obtain an aluminum foil with a thickness of 0.045 mm and one smooth side. Step S7: The aluminum foil material was annealed in an annealing furnace at a heating rate of 40 °C / hour, a holding temperature of 270 °C, and a holding time of 15 hours, then cooled to obtain a medium-thick aluminum foil material, and finally taken out of the furnace and cooled.

[0034] Components of the aluminum foil materials in Examples 1 to 8 and Comparative Examples 1 to 3

[0035] [Table 1]

[0036] Measurement of the properties of the aluminum foil materials 1. Grain size: After mechanical polishing and electrolytic polishing of the aluminum foil material, the microstructure morphology was characterized using a FEI Apreo C field emission scanning electron microscope. The electrolytic polishing solution used was perchloric acid: absolute ethanol (volume ratio) = 1:9. After the test was completed, the original data was processed using TSL OIM analysis software, and the grain size was statistically analyzed.

[0037] 2. Tensile strength and elongation: Samples with a gauge length of 100 mm and a width of 15 mm were prepared using a cutter of model JDC, and a tensile test was performed at a tensile speed of 25 mm / min using a 10 kN material tensile testing machine from Instron. There were 5 parallel samples for each group, and the average value was selected as the experimental result.

[0038] 3. Erichsen value: The aluminum foil material was cut into a 70×70 mm square, and an Erichsen test was performed on a GBW-60Z Erichsen testing machine at a press speed of 10 mm / min, a clamping force of 10 kN, and a punch diameter of 20 mm, and the test was stopped when the force value decreased by 0.6%. Four sets of parallel tests were performed for each parameter, and the average value was taken as the final Erichsen value. Table 2 shows the properties of the aluminum foil materials in Examples 1 to 8 and Comparative Examples 1 to 3.

[0039] Properties of the aluminum foil materials in Examples 1 to 8 and Comparative Examples 1 to 3

[0040]

Table 2

[0041] From the above results, it was found that the aluminum foil materials of Examples 1 to 8 having the specific composition of the present invention exhibited excellent properties in terms of tensile strength, elongation, and Erichsen value. Compared with Comparative Examples 1 to 3, the aluminum foil materials in Examples 1 to 8 of the present application have a crystal grain size of ≦10 μm, a tensile strength of ≧110 MPa, an elongation of ≧20%, and an Erichsen value of ≧7.2 mm. In particular, in Comparative Example 3, since the Cr content exceeds 0.03%, it causes a lower elongation of the aluminum foil.

[0042] Manufacture of Aluminum Foil Materials of Examples 9 to 14 and Comparative Example 4 The manufacturing methods of the aluminum foil materials of Examples 9 to 14 and Comparative Example 4 are the same as those of Examples 1 to 8, except that some process parameters are changed. Refer to Table 3 for the process parameters. The measuring methods for the properties of the aluminum foil materials of Examples 9 to 14 and Comparative Example 4 are the same as those of Examples 1 to 8. Each property of the aluminum foil material is shown in Table 3.

[0043] Process Parameters and Properties of Aluminum Foil Materials of Examples 9 to 14 and Comparative Example 4

[0044]

Table 3

[0045] From the above results, it was found that according to the method of the present invention, through processes such as specific homogenization treatment and rolling deformation, the aluminum foil materials of Examples 9 to 14 achieved significantly better properties compared to Comparative Example 4. In the present application, the aluminum foil materials in Examples 9 to 14 have a crystal grain size of ≦10 μm, a tensile strength of ≧110 MPa, an elongation of ≧20%, and an Erichsen value of ≧7.2 mm.

[0046] The above embodiments are only illustrative of the technical solutions of the present disclosure and do not limit its scope. Those skilled in the art can make various modifications with reference to the above examples, but all of them should be within the protection scope of the present disclosure as long as they do not deviate from the design concept of the present disclosure.

[0047] The above relates to specific embodiments of the present disclosure and is not intended to limit the present disclosure. For those skilled in the art, various modifications and changes can be made to the present disclosure. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle scope of the present disclosure shall be included in the protection scope of the present disclosure.

Claims

1. An aluminum foil material, Based on the total weight of the aluminum foil material, the aluminum foil material comprises: 0 wt% to 2.0 wt% of Fe, 9 wt% to 1.8 wt% of Si, 001 wt% to 0.05 wt% of Cu, 001 wt% to 0.05 wt% of Mn, 001 wt% to 0.05 wt% of Mg, 0001 wt% to 0.03 wt% of Cr, 001 wt% to 0.05 wt% of Ti, The balance of Al, and The weight ratio of Fe to Si is within the range of 1.1 to 2.2, and The aluminum foil material has a grain size ≦ 10 μm, a tensile strength ≧ 110 MPa, an elongation ≧ 20%, and an Erichsen value ≧ 7.2 mm. An aluminum foil material characterized by this.

2. Based on the total weight of the aluminum foil material, the aluminum foil material comprises: 1 wt% to 1.7 wt% of Fe, 1 wt% to 1.7 wt% of Si, 001 wt% to 0.04 wt% of Cu, 001 wt% to 0.04 wt% of Mn, 001 wt% to 0.04 wt% of Mg, 0001 wt% to 0.03 wt% of Cr, 001 wt% to 0.04 wt% of Ti, The balance of Al. The aluminum foil material according to claim 1, characterized by this.

3. Based on the total weight of the aluminum foil material, the aluminum foil material comprises: 2 wt% to 1.5 wt% of Fe, 1 wt% to 1.5 wt% of Si, 001 wt% to 0.04 wt% of Cu, 001 wt% to 0.04 wt% of Mn, 001 wt% to 0.04 wt% of Mg, 0005 wt% to 0.02 wt% of Cr, 001 wt% to 0.04 wt% of Ti, The balance of Al. The aluminum foil material according to claim 1, characterized by this.

4. The weight ratio of Fe to Si is within the range of 1.1 to 1.

5. The aluminum foil material according to any one of claims 1 to 3, characterized by this.

5. The weight ratio of Fe to Si is within the range of 1.1 to 1.

3. The aluminum foil material according to any one of claims 1 to 3, characterized by this.

6. A method for manufacturing the aluminum foil material according to any one of claims 1 to 3, comprising: Step S1 of adding raw materials to a melting furnace to melt the raw materials to obtain a molten alloy, Step S2 of refining the grain size of the molten alloy, degassing, filtering, and then casting and rolling it into a casting and rolling slab with a thickness of 6.0 mm to 10.0 mm. Step S3 of cold rolling the cast and rolled slab to obtain a cold rolled billet with a thickness of 2.0 mm to 5.0 mm; Step S4 of subjecting the cold rolled billet to a homogenization treatment at a temperature of 520°C to 620°C for 5 hours or more to obtain a homogenized cold rolled billet; Step S5 of cold rolling the homogenized cold rolled billet to obtain a foil rolled billet with a thickness of 0.2 mm to 1.5 mm; Step S6 of rolling the foil rolled billet to produce an aluminum foil; Step S7 of annealing the aluminum foil at a temperature of 200°C to 340°C at a heating rate of 20°C / hour or more for 2 hours or more to obtain the aluminum foil material, the manufacturing method being characterized by including these steps.

7. The method according to claim 6, characterized in that in step S6, the thickness of the aluminum foil is 0.015 mm to 0.06 mm.

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