JP5116403B2 - Aluminum alloy and packaging material and electrical / electronic structural member using the same - Google Patents

Description

  The present invention relates to an aluminum alloy having excellent corrosion resistance, a packaging material using the aluminum alloy, and an electrical and electronic structural member. Particularly, the present invention has high strength and sufficient elongation for improving formability, and further exhibits excellent rolling properties. The present invention relates to aluminum alloys for packaging materials for beverages, foods, medicines, etc., for electrical and electronic structural members such as battery packaging materials and battery electrodes, for building materials, for machine parts, for home use and for decoration.

  Among aluminum alloys, especially for food packaging materials containing chemicals and salt, or for electronic materials that come into contact with electrolytes, it must have sufficient elongation to improve its corrosion resistance and strength, and formability. Since it is required, aluminum alloys such as JIS (Japanese Industrial Standards) names 3003, 3004, 5052, 1N30 and 8079 having a thickness of about 6 to 200 μm are usually used. Table 1 shows typical compositions of these alloys.

  In these alloys, a corrosion phenomenon called pitting corrosion is generally likely to occur.

  In order to prevent this pitting corrosion, for example, JP-A-3-261549 (Patent Document 1) discloses a clad material in which a high-purity aluminum film is formed on the surface as a skin material. JP-A-60-221546 (Patent Document 2) discloses a technique for preventing pitting corrosion by adding zinc to an aluminum alloy. Further, JP-A-10-183283 (Patent Document 3) discloses an aluminum alloy clad material excellent in corrosion resistance using an aluminum alloy containing tin as a skin material.

  However, when high-purity aluminum is used as the skin material, since the high-purity aluminum is too soft, fine powder is likely to be generated at the time of molding, which causes a problem of contamination.

  Further, when zinc or tin is added, pitting corrosion can be prevented, but the material is totally corroded. For this reason, the amount of corrosion is large and it is not suitable for packaging materials such as food.

  Furthermore, the use of a clad material as a food packaging material is often unprofitable in terms of cost, such as difficulty in thin foil rolling.

  In addition, aluminum alloys used as packaging materials for beverages, foods, medicines, and the like require strength and formability, but those described in the above-mentioned publications are sufficient to satisfy these characteristics. There wasn't.

  Fields other than for packaging materials, that is, used in a thickness of 10 μm or less, for example, for building materials used as heat insulating materials, for machine parts, for electronic materials such as battery packaging materials and battery electrodes, for home use and for decoration Aluminum alloy foils are also required to have high corrosion resistance and high strength. However, aluminum alloys such as the above JIS names 3003, 3004, and 5052 have high work hardening during rolling, and it has been difficult to roll into foils having a thickness of 10 μm or less. In particular, in 3004 and 5052 aluminum alloys, it was practically impossible to obtain an aluminum alloy foil of 20 μm or less.

  For these thin foils, an aluminum-iron alloy such as JIS name 8079 shown in Table 1 is usually used. However, in these alloys, the presence of an aluminum-iron-based intermetallic compound causes a decrease in corrosion resistance and suppresses refinement of crystal grains for obtaining sufficient strength. Therefore, these aluminum alloys were insufficient in strength and were never satisfactory.

  In addition, International Publication No. WO01 / 004369 (Patent Document 4) includes 0.0001 mass% or more and 0.03 mass% or less of copper, 0.0005 mass% or more and 0.2 mass% or less of silicon, An aluminum alloy containing 0.5% by mass or more and 4% by mass or less of manganese and 0.5% by mass or more and 3% by mass or less of iron and the balance containing aluminum and inevitable impurities is disclosed. However, although this alloy is superior in strength, formability and workability to conventional aluminum alloys, it is not sufficient to prevent pitting corrosion and general corrosion, for example, good corrosion resistance even in electrolytes and soy sauce stock solutions. Could not be maintained.

Furthermore, Japanese Patent Application Laid-Open No. 2007-16308 (Patent Document 5) can prevent pitting corrosion and overall corrosion without processing into the form of a clad material, and is excellent in strength, formability and workability. As aluminum alloy, 0.1 mass% or more and 6 mass% or less manganese, 0.001 mass% or more and 0.02 mass% or less iron, 0.0005 mass% or more and 0.02 mass% or less silicon, What contains 0.0001 mass% or more and 0.03 mass% or less of copper, and the remainder contains aluminum and inevitable impurities is disclosed. However, although this alloy can maintain good corrosion resistance in an electrolytic solution and food containing salt, it is not sufficient as a packaging material for chemicals.
Japanese Patent Laid-Open No. 3-261549 JP-A-60-221546 Japanese Patent Laid-Open No. 10-183283 International Publication No. WO01 / 004369 Pamphlet JP 2007-16308 A

  Therefore, the present invention has been made to solve the above-described problems, and the object of the present invention is to prevent pitting corrosion and overall corrosion without processing into the form of a clad material, An aluminum alloy that shows good corrosion resistance to chemicals as well as in electrolytes and foods that contain salt, and that excels in strength, formability, and workability, and for medicines and foods using the aluminum alloy It is to provide a packaging material and an electrical and electronic structural member.

  In order to solve the above-mentioned problems, the present inventors have made various studies. As a result, manganese increases the strength without impairing the corrosion resistance of the aluminum alloy, and by selecting an appropriate content and processing method, the moldability can be improved. It was found to be an element that can give sufficient elongation for goodness and high rollability for obtaining a thin foil.

  It has also been found that the presence of various impurities, particularly iron, copper, and zinc, together with manganese, significantly reduces the corrosion resistance of the aluminum alloy.

  Further, it has been found that the presence of silicon and magnesium in a certain amount after iron, copper and zinc described above significantly reduces the corrosion resistance of the aluminum alloy.

  Based on these findings, the present inventors have succeeded in developing an aluminum alloy that is excellent not only in corrosion resistance, particularly in foods containing electrolytes and salt, but also in chemical resistance, strength, formability, and rolling properties.

Based on these findings, the aluminum alloy according to the present invention comprises 93% by mass or more of aluminum, 0.1% by mass or more and 6% by mass or less of manganese, and 0.00001% by mass or more and 0.001% by mass or less. Iron, 0.00001 mass% or more and 0.03 mass% or less copper, 0.00001 mass% or more and 0.001 mass% or less zinc , and 0.00001 mass% or more and 0.001 mass% or less silicon And 0.00001 mass% or more and 0.001 mass% or less of magnesium, and the balance consists of inevitable impurities.

  The packaging material according to the present invention is made of an aluminum alloy having any one of the above-described compositions, and has a thickness of 6 μm or more and 200 μm or less.

  The electrical / electronic structural member according to the present invention is made of an aluminum alloy having any one of the above-described compositions, and has a thickness of 4 μm or more and 1 mm or less.

  As described above, according to the present invention, it is possible to obtain an aluminum alloy having excellent corrosion resistance against chemicals as well as strength, formability and rollability, as well as corrosion resistance, particularly in foods containing salt and salt, In addition, chemical and food packaging materials and electrical and electronic structural members made of the aluminum alloy can be obtained.

  Hereinafter, the reason why each element is added, the range of the amount added, conditions of the manufacturing method, and the like will be described in detail.

(1) Manganese (Mn): 0.1% by mass or more and 6% by mass or less Manganese is an element that improves the strength without greatly reducing the corrosion resistance of the aluminum alloy. If the manganese content is less than 0.1% by mass, sufficient strength cannot be obtained. Moreover, when the content rate of manganese exceeds 6 mass%, elongation and a moldability will fall. Therefore, it is necessary to make the manganese content 0.1% by mass or more and 6% by mass or less. In order to combine the corrosion resistance, strength, formability, and rollability of the aluminum alloy, it is more preferable that the manganese content is 1.0 mass% or more and 4.0 mass% or less.

(2) Iron (Fe): 0.00001 mass% or more and 0.001 mass% or less Iron forms an aluminum-iron-manganese intermetallic compound together with the above-described manganese. The aluminum-iron-manganese-based intermetallic compound is represented by Al ₆ (Fe, Mn) or the like, and is different from the aluminum-manganese-based intermetallic compound Al ₆ Mn, for example, a food or electrolyte containing chemicals and salt. In an acidic to strongly acidic environment such as the above, the corrosion resistance of the aluminum alloy is extremely lowered, causing pitting corrosion and general corrosion.

  When the iron content exceeds 0.001% by mass, the corrosion resistance is remarkably lowered. In the aluminum alloy of the present invention, as a method for setting the iron content to 0.001% by mass or less, for example, a high-purity aluminum ingot by a high-grade three-layer electrolytic method may be appropriately used.

  The lower limit of the iron content is not particularly limited, but is usually about 0.00001% by mass. This is because, in order to make the iron content less than 0.00001% by mass, it is necessary to repeat the three-layer electrolysis method, and the manufacturing cost is remarkably increased.

(3) Copper (Cu): 0.00001% by mass or more and 0.03% by mass or less Even if copper exists in a trace amount in the aluminum alloy, the corrosion resistance of the aluminum alloy is lowered. Therefore, the copper content is set to 0.03% by mass or less. The lower limit of the copper content is not particularly limited, but is usually about 0.00001% by mass. This is because, in order to make the copper content less than 0.00001% by mass, it is necessary to repeat the fractional crystallization method and the like, and the manufacturing cost becomes remarkably high. Preferably, the copper content is 0.02 mass% or less, more preferably 0.01 mass% or less.

(4) Zinc (Zn): 0.00001 mass% or more and 0.001 mass% or less Even if zinc exists in a trace amount in an aluminum alloy, it reduces the corrosion resistance of the aluminum alloy. Therefore, the content rate of zinc shall be 0.001 mass% or less. The lower limit of the zinc content is not particularly limited, but is usually about 0.00001% by mass. This is because, in order to make the zinc content less than 0.00001% by mass, it is necessary to repeat the three-layer electrolysis method and the like, and the manufacturing cost becomes remarkably high.

(5) Silicon (Si): 0.00001% by mass or more and 0.001% by mass or less When silicon is present in an aluminum alloy, the corrosion resistance of the aluminum alloy is significantly reduced in an acidic environment, and causes pitting corrosion. . Further, when the silicon content is reduced, the crystal grain size of the aluminum alloy is reduced. Thereby, the yield strength of the aluminum alloy, that is, the strength is increased, and the elongation of the aluminum alloy, that is, the formability can be improved. In order to exhibit these characteristics, the silicon content must be 0.001% by mass or less. Preferably, the silicon content is 0.0005 mass% or less.

  The lower limit of the silicon content is not particularly limited, but is usually about 0.00001% by mass. This is because, in order to reduce the silicon content to less than 0.00001 mass%, it is necessary to repeat the three-layer electrolysis method, and the manufacturing cost is remarkably increased.

(6) Magnesium (Mg): 0.00001% by mass or more and 0.001% by mass or less Magnesium is easily concentrated in an oxide film formed on the surface of aluminum, and causes film defects. Reduce. Therefore, the magnesium content is set to 0.001% by mass or less. The lower limit of the magnesium content is not particularly limited, but is usually about 0.00001% by mass. This is because, in order to make the magnesium content less than 0.00001 mass%, it is necessary to repeat the three-layer electrolysis method and the like, and the manufacturing cost becomes remarkably high.

(7) Aluminum (Al): 93% by mass or more In the aluminum alloy of the present invention, the aluminum purity measured according to the method described in JIS H2111 is 93% by mass or more.

  The aluminum alloy of the present invention has a content that does not affect the above characteristics and effects, and vanadium (V), titanium (Ti), zirconium (Zr), chromium (Cr), nickel (Ni), etc. Transition elements, boron (B), gallium (Ga), bismuth (Bi) and other elements may be included.

  As described above, according to the present invention, since the optimum amount of the above-described additive elements is added to aluminum, the recrystallized structure of the aluminum alloy becomes ultrafine. As a result, the strength and formability of the aluminum alloy can be improved at the same time, and the corrosion resistance is excellent enough to prevent pitting corrosion and overall corrosion by optimizing the manganese and iron contents. The characteristics of the aluminum alloy according to the present invention.

(8) Thickness of aluminum alloy for packaging material: 6 μm or more and 200 μm or less If the thickness of the aluminum alloy is less than 6 μm, the strength as a packaging material for drugs and foods cannot be maintained. Moreover, when thickness exceeds 200 micrometers, while shaping | molding as a packaging material becomes difficult, weight and cost increase. Therefore, the thickness of the aluminum alloy needs to be 6 μm or more and 200 μm or less. More preferably, the thickness of the aluminum alloy is 6 μm or more and 100 μm or less.

(9) Thickness of aluminum alloy for electrical / electronic structural member: 4 μm or more and 1 mm or less If the thickness of the aluminum alloy is less than 4 μm, the strength as an electrical / electronic structural member such as an electrode cannot be maintained. Moreover, when thickness exceeds 1 mm, while it becomes difficult to shape | mold as an electric-electronic structural member, weight and cost increase. Therefore, the thickness of the aluminum alloy needs to be 4 μm or more and 1 mm or less. More preferably, the aluminum alloy has a thickness of 10 μm or more and 500 μm or less.

  In order to make the thickness of the aluminum alloy within the above range, casting and rolling may be performed according to a normal method. Moreover, you may heat-process suitably.

  As described above, according to the present invention, it is possible to provide an aluminum alloy in which neither pitting corrosion nor overall corrosion occurs and the strength and elongation can be improved at the same time. Even if this aluminum alloy is not processed into the form of a clad material, it is processed into an aluminum alloy foil as it is and used as a packaging material and an electrical / electronic structural member, so that it has excellent corrosion resistance and has high formability and strength. An electronic structural member can be provided at low cost.

  In addition, the foil made of an aluminum alloy developed in the present invention is used not only for packaging materials and as electrical and electronic structural members, but also in all fields of thin foils that require corrosion resistance, that is, for building materials and machines as heat insulating materials. Sufficient effects can also be exhibited in the fields of parts, packaging for the purpose of preventing the deterioration of food and chemicals, batteries, fins, households and decorations.

  The above food includes seasonings such as soy sauce, miso, sauce, ketchup, mayonnaise, salt, butter, margarine and cheese, and includes any form from liquid to solid.

  In addition, as said chemical | drug | medicine, sanitary goods, such as a gargle, a detergent, a cleaning agent, and cosmetics, shall also include any form from a liquid to a solid.

  Furthermore, the composition of this aluminum alloy is not limited to use in the field of foils and foils, but also exhibits a sufficient effect as a composition of a thicker plate material that requires corrosion resistance or a composition for powder metallurgy. It is.

  Examples of the present invention will be described below.

First, aluminum alloy plates having a thickness of 6 mm were prepared by melting and casting aluminum alloys having various compositions (composition Nos. 1 to 18) by a continuous casting method having a cooling rate of about 10 ³ ° C / second. In addition, composition No. 14-18 have the composition of 3003, 3004, 5052, 1N30, 8079 of JIS name, respectively. These compositions are shown in Table 2. In Table 2, in the numerical values shown in the column “Al”, for example, “> 99” means that the aluminum (Al) content exceeds 99 mass%.

  These aluminum alloy plates were heat-treated at a temperature of 400 ° C. for 5 hours, removed from the furnace, rolled into a foil having a thickness of 85 μm, and further heat-treated at a temperature of 350 ° C. for 10 hours.

The mechanical properties (proof stress [N / mm ² ] and Erichsen value [mm]) of the obtained aluminum alloy foil were measured. The Eriksen value was measured by an Erichsen test based on JIS Z 2247, which evaluates deformability (extrusion property) as one of the moldability evaluations.

  Further, in the following tests A to D, the obtained aluminum alloy foil was immersed in or contacted with six types of liquids (food and industrial materials) for 720 hours to observe the corrosion state.

  Test A: The above aluminum alloy foil was immersed or brought into contact with 3% by mass saline kept at a temperature of 50 ° C. for 720 hours.

  Test B: The above-described aluminum alloy foil was immersed or brought into contact with soy sauce maintained at a temperature of 50 ° C. (trade name Kikkoman Soy Sauce Noguchi, manufactured by Kikkoman Corporation) for 720 hours.

Test C: The above-described aluminum alloy foil was immersed or brought into contact with a 1 mol LiPF ₆ electrolyte kept at a temperature of 40 ° C. (the solvent was 1 part by weight of ethylene carbonate and 1 part by weight of diethylene carbonate) for 720 hours.

  Test D: The above aluminum alloy foil is immersed in a liquid prepared by dissolving cheese (trade name QBB natural cheese, manufactured by Rokko Butter Co., Ltd.) at a temperature of 50 ° C., and the cheese is re-solidified by returning to 30 ° C. After that, the temperature was kept at 30 ° C. for 720 hours.

  Test E: The above-mentioned aluminum alloy foil was immersed or brought into contact with a mouthwash (trade name isodine manufactured by Meiji Seika Co., Ltd.) maintained at a temperature of 25 ° C. for 720 hours.

  Test F: The above-mentioned aluminum alloy foil was immersed or brought into contact with a face washing foam (trade name Biore face washing foam manufactured by Kao Corporation) maintained at a temperature of 25 ° C. for 720 hours.

  The measurement results were evaluated in three stages (◯, Δ, ×) in order from the one with good corrosion resistance.

  The above measurement results are shown in Table 3.

  From Tables 2 and 3, the composition No. The aluminum alloy foils 1 to 8 are superior in all of the proof stress, the Erichsen value and the corrosion resistance to the conventional JIS designations 3003, 3004, 5052, 1N30 and 8079 aluminum alloys (composition Nos. 14 to 18). Recognize.

  In addition, composition No. having a composition outside the scope of the present invention. The composition No. 9 according to the present invention was also applied to aluminum alloy foils 9 to 13. It can be seen that the aluminum alloy foils 1 to 8 are excellent in comprehensive evaluation of the proof stress, the Erichsen value, and the corrosion resistance.

Further, the proof stress of an aluminum alloy of JIS name 8079, which has been conventionally used as a thin foil for packaging materials, is about 35 N / mm ² at a thickness of 10 μm, and does not show any corrosion resistance like the aluminum alloy of the present invention. This shows that the aluminum alloy disclosed in the present invention is very effective even for thin foils.

  It should be considered that the embodiments and examples disclosed herein are illustrative and non-restrictive in every respect. The scope of the present invention is shown not by the above embodiments or examples but by the scope of claims, and is intended to include all modifications and variations within the meaning and scope equivalent to the scope of claims. .

  Since the aluminum alloy according to the present invention has excellent corrosion resistance and high formability and strength, it is not only used as a packaging material and as an electric / electronic structural member, but also in all fields of thin foils that require corrosion resistance, that is, heat insulation. It can be used in the fields of building materials, machine parts, packaging materials for the purpose of preventing the deterioration of food and chemicals, fin materials, household and decorative fields. In addition to the use in the above, it can be sufficiently used for a thicker plate material requiring corrosion resistance or for powder metallurgy.

Claims (3)

93 mass% or more aluminum, 0.1 mass% or more and 6 mass% or less manganese, 0.00001 mass% or more and 0.001 mass% or less iron, 0.00001 mass% or more and 0.03 mass% or less Copper, 0.00001 mass% or more and 0.001 mass% or less of zinc , 0.00001 mass% or more and 0.001 mass% or less of silicon, and 0.00001 mass% or more and 0.001 mass% or less of magnesium wherein the door, with the balance being inevitable impurities, aluminum alloy. A packaging material comprising the aluminum alloy according to claim 1 and having a thickness of 6 µm to 200 µm. An electrical and electronic structural member made of the aluminum alloy according to claim 1 and having a thickness of 4 μm to 1 mm.