JPS61250153A - Manufacture of aluminum alloy foil suitable for use as laminating material on plastic film for cap seal - Google Patents

Abstract

PURPOSE:To manufacture the titled Al alloy foil causing hardly spring-back at a low cost by cold rolling an Al alloy ingot contg. a specified amount of Fe so as to provide a hard or semihard refined state. CONSTITUTION:An Al alloy ingot consisting of 0.1-1.2wt% Fe and the balance Al with inevitable impurities is essentially cold rolled and is optionally annealed at a low temp. or annealed and rolled at a low draft so as to provide a hard or semihard refined state. Thus, Al alloy foil suitable for use as a laminating material on a plastic film for a cap seal is obtd. The Al alloy foil has >=about 10.5kgf/mm<2>, preferably <=about 25kgf/mm<2> tensile strength and >=about 5.5kgf/ mm<2> offset yield stress strength at 0.2% permanent set and hardly causes spring- back.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application This invention relates to a method for producing an aluminum alloy foil suitable for laminating with a synthetic resin film to form a laminate material for use in lid seals for food and drink containers, etc. .

Conventional Technology and Problems As is well known, aluminum or aluminum alloy foil is widely used for food and pharmaceutical packaging containers, etc.
In particular, when used as a material for cap seals for food and drink containers, etc., the material is particularly required to have excellent strength, not to break easily, and to have little elastic deformation (so-called springback) after molding. .

Conventionally, such aluminum foil for cap seals has been made of a soft foil (so-called 0 material) obtained by annealing a pure aluminum alloy such as 1N30 alloy. This is based on the fact that the springback of the foil decreases as the foil becomes softer, but on the other hand, the strength decreases, so the foil must be thicker, approximately 30 to 100 μm. This caused an increase in costs.

In order to increase the strength of the foil itself in its softest state, attempts have been made to add reinforcing elements such as Mg and Mn, but rolling resistance increases and significant cost reductions cannot be expected.

Therefore, in order to reduce costs by thinning the aluminum foil itself while maintaining the strength required as a material for cap seals, a so-called An laminate material, in which the above-mentioned soft part is bonded to a synthetic resin film, has recently been used. It is becoming.

However, in this case, since the elastic modulus of the synthetic resin film is low, the springback of the laminate material after drawing is generally large, and the shape of the laminate material is even different from that of the drawing punch, causing processing problems in the next process. This resulted in drawbacks such as the risk of causing problems.

This invention was made in view of such circumstances, and
This was made with the intention of providing an aluminum alloy foil for realizing an AQ laminate material for cap seals that has less springback and is inexpensive.

Means for solving the problem In order to achieve this objective, the inventors conducted various experiments and research, and found that the springback of AQ laminate material was determined by the strength of the aluminum foil laminated to the synthetic resin film. There is a close relationship, especially when the tensile strength of the foil is 10.5Ng.
f/- or more, preferably 12.589 f/- or more, and the 0.2% proof stress is 5.5 Ngf/- or more,
The present invention has been completed as a result of discovering how to effectively achieve the above object, and based on this knowledge, conducting further research on a method for producing aluminum alloy foil that satisfies this condition.

That is, in this invention, an aluminum alloy ingot containing 0.1 to 1.2 wt% of l"e and the remainder consisting of aluminum and unavoidable impurities is cold rolled as an essential step, and then annealed at a low temperature. An aluminum alloy suitable for a synthetic resin film laminate material for cap seals, which is produced in a hard or semi-hard tempered state by performing (H2n) or rolling (H1n) at a low reduction rate in an annealing machine as an optional step. The gist is the method for manufacturing foil.

First of all, in the composition of aluminum alloy foil, the 1"e content is limited to 0.1 to 1.2 Tllt%. If it is less than the lower limit, the strength improvement effect is poor, and the metal cost is high, so it is difficult to make the foil thinner. This is because cost reduction cannot be expected.On the other hand, if the upper limit is exceeded, the strength of the final streak becomes large regardless of the quality II treatment, and there is no point in applying this invention. .

Next, the manufacturing method will be described. In this invention, an aluminum alloy ingot having the above composition is subjected to cold rolling as an essential step. Before cold rolling,
This does not preclude subjecting the ingot to homogenization treatment, hot rolling, etc. Alternatively, cold rolling may be divided into primary cold rolling and secondary cold rolling, and intermediate annealing may be performed between them.

If this cold rolling is carried out as the final foil rolling process, the resulting aluminum foil will be hard (H), but in this invention, as an optional step, annealing at a low temperature is performed after cold rolling, or By rolling with a low reduction rate in an annealing machine, it is allowed to achieve a refining state of semi-hard (1/2H) or more. The annealing performed after cold-open rolling is generally carried out at a temperature of about 200 to 250°C for 30 minutes to 5 hours, preferably at 220 to 230°C, if rolling is not performed afterwards. It is carried out for 1 to 2 hours.

On the other hand, when rolling is performed, it is desirable that complete annealing be performed at a temperature equal to or higher than the recrystallization temperature. Further, the rolling reduction ratio in the rolling mentioned after annealing is desirably set in a range of about 10 to 50%, and more preferably in a range of 20 to 30%. In addition, the hard or semi-hard tempered state means that the tensile strength of the alloy foil is 10.5 inf/- or more, 0.2%
This is to make the yield strength 5.5 and 9f/ae1 or more. Incidentally, if the tensile strength is too high, the resistance to rolling deformation increases and handling becomes inconvenient, so it is desirable that the tensile strength is 25 Kgf/- or less. In the present invention, it is also recommended to perform cleaning for degreasing after rolling, if necessary.

In addition, as the synthetic resin film to be laminated with the aluminum foil produced by the above method, it is recommended to use relatively heat-resistant materials such as boli-O-pyrene, polyester, and nylon since lamination is performed by heat sealing. desirable.

As described in detail, according to the present invention, the tensile strength is 10
．． 5 illusion f/j, 0.2% yield strength of 5.5 Kgf/- or more can be manufactured, and by using this alloy foil, springback can be reduced as is clear from consideration of the examples. It is possible to realize an AQ laminate material suitable for use in small cap seals.

Since it is superior in strength to conventional foils made from 1-30 alloys treated with 0 material, it is possible to make the foil itself thinner than laminate materials using conventional foils, which also reduces costs. be able to.

Example Next, examples of the present invention will be shown in comparison with comparative examples.

Purlin slabs of aluminum alloys with various compositions shown in Table 1 were sequentially subjected to hot rolling, secondary cold rolling, intermediate annealing, and secondary cold rolling (foil rolling), and then Sample N of Examples
For α1 to 4, hard foil (1-1) is used as rolled.
and 200 to 250 for samples Nα5 to 8.
The foils were annealed at 300° C. to become semi-hard foils (1/2H), and those of comparative examples were annealed at 300° C. or higher to become soft foils (0). and the tensile strength of these foils, 0.2%
The yield strength of each was measured. The results are shown in the same table. still,
Three types of 8 foils were produced with thicknesses of 10 μm, 20 μm, and 30 μm, and the tensile strength and 0.2% proof stress were shown as the average value of these.

Table 1 Next, for each of the above alloy foils with a thickness of 20 μm, polyester films with a thickness of 15 μm and 6 μm were laminated on both sides of the foil, a punch diameter of 32 mm, a blank diameter of 50 s, a clearance of 0.5 to 0.6 mm, Drawing processing was performed under processing conditions of a wrinkle presser of 20 kgf or less, and the amount of springback after processing was investigated. The amount of springback was evaluated by the difference between the maximum outer diameter of the molded body and the punch diameter after processing. The results are shown in Table 2.

[Margin below] As is clear from the above results in Table 2, the aluminum alloy foil manufactured by the present invention has a tensile strength of 10.5 kyf.
/- and the 0.2% proof stress exceeded 5.5 kyf/-, and it was confirmed that the springback of the laminate material was less than that of the comparative example.

that's all

Claims (1)

[Claims] An ingot of an aluminum alloy containing 0.1 to 1.2 wt% of Fe with the balance consisting of aluminum and unavoidable impurities is subjected to cold rolling as an essential step, and then annealed at a low temperature or by a low reduction rate after annealing. A method for producing an aluminum alloy foil suitable for a synthetic resin film laminate material for cap seals, characterized by performing rolling as an optional step and producing the foil in a hard or semi-hard tempered state.