Method for producing a strip for packaging purposes

Abstract

A method for producing a strip consisting of aluminum or an aluminum alloy for packaging purposes, in particular for cans, can lids or can closures, which provides an individualized aluminum strip for packaging purposes, with which decorative or identification elements can be reliably embossed without additional production steps being required, for example at the producer of the packaging means, is achieved in that decorative or other identification elements are embossed into the strip in the last rolling pass of cold rolling and in that the strip thickness is greater in the area of the decorative and identification elements than in the remaining areas of the strip.

Claims

1. Method for producing a strip consisting of aluminum or an aluminum alloy for packaging purposes, the method comprising embossing decorative or other identification elements into the strip during a last rolling pass of cold rolling, the strip thickness is greater in an area of the decorative or identification elements than in remaining areas of the strip and an amplitude of an embossing profile in the strip is at most 4 m.

2. Method according to claim 1, wherein at least one of work rolls used during cold rolling has depressions for embossing the decorative or identification elements into the strip.

3. Method according to claim 1, wherein the decorative or identification elements are embossed in-line with production of the strip for packaging purposes.

4. Method according to claim 1, wherein after finish-rolling the strip is wound onto a coil.

5. Method according to claim 1, wherein reduction per pass during the embossing rolling pass is between 20% and 40%.

6. Method according to claim 1, wherein work rolls of an embossing roll pair have different grinding structures.

7. Method according to claim 1, wherein a last, embossing rolling pass is carried out in a sexto roll stand.

8. Method according to claim 1, wherein a final strip thickness is 0.15 mm to 0.5 mm.

9. Method according to claim 1, the strip consists of a 5xxx aluminum alloy.

10. Strip according to claim 1, consisting of aluminum or an aluminum alloy, the strip comprising embossed decorative or identification elements and having a strip thickness greater in an area of the decorative or identification elements than in remaining areas of the strip, wherein an amplitude of an embossing profile in the strip is at most 4 m.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) There are many ways of enhancing and further developing the method according to the invention and the strip according to the invention. For this purpose, reference is made, on the one hand, to the claims and to the description of an exemplary embodiment in conjunction with the drawing. The drawing shows in

(2) FIG. 1 a schematic view of a finishing roll train for carrying out the method according to the invention for producing an aluminum strip for packaging purposes,

(3) FIG. 2 a work roll pair of the finishing roll stand from FIG. 1 and

(4) FIG. 3 in a schematic, sectional view, an exemplary embodiment of a strip according to the invention for packaging purposes.

DESCRIPTION

(5) FIG. 1 shows an exemplary embodiment of a finishing roll train 1 for cold rolling an aluminum strip 2 which has been produced, for example, by hot rolling a slab. The aluminum strip 2 is uncoiled from a decoiler 3 and conveyed to further processing steps 4. The further production steps can, for example, consist of cold rolling and intermediate annealing as a strip. They are, however, not necessary to implement the present invention. The production steps 4 can, therefore, also be omitted, provided, for example, that the strip is intermediately annealed in batches, i.e. intermediately annealed while being wound on a coil, and then conveyed to the last rolling pass.

(6) In the last rolling pass in a sexto roll stand 5, the strip is rolled to the final thickness, wherein preferably the reduction per pass is between 20 to 40%. In the present exemplary embodiment, the work roll 5a has depressions for embossing decorative or other identification elements, which during the final rolling pass causes areas with an increased strip thickness to be introduced, namely the areas of the decorative or identification elements. Of course, instead of the sexto roll stand, it is also possible for other roll stands to be employed. Up to now, however, good embossing results have only been confirmed on a sexto roll stand.

(7) The aluminum strip rolled to the final thickness in such a way is then wound onto a coiler 6. However, before winding, yet more production steps, for example surface treatment, can be carried out. The final thickness of the aluminum strip in the present exemplary embodiment is 0.2 mm to 0.35 mm. By the use of the aluminum alloy, preferably a type 5xxx aluminum alloy, a particularly high strength for the aluminum strip and, at the same time, good deformability thereof during further processing is possible even with the narrow wall thicknesses.

(8) By individualizing the aluminum strip with the method according to the invention, the secondary producer is able to identify the products produced from it without having to resort to other technologies, for example additional imprinting or the like. All additional production steps increase the production costs which are very important with these products.

(9) In FIG. 2, the work roll pair 5a, 5b, used in the sexto roll stand illustrated in FIG. 1, is illustrated schematically in a perspective view. Whilst the work roll 5a has depressions 7, which are used to emboss decorative or identification elements into the aluminum strip, no depressions are provided on the work roll 5b. The strip produced in such a way therefore has decorative or identification elements which in one direction out of the plane of the strip have a greater strip thickness than the remaining strip areas. Both work rolls 5a, 5b have different grinding structures to optimize the flow of material into the depressions when the strip is finish-rolled, so that the flow of the aluminum material into the depressions of the work roll 5a in the roll gap is supported during finish-rolling. However, it is also possible for both work rolls 5a and 5b to have depressions for embossing decorative or identification elements.

(10) As a result, at the end of finish-rolling, an aluminum strip 2 for packaging purposes is wound onto a coil, which was not so greatly reduced in thickness in the area of the decorative elements 8 and in this respect has a greater strip thickness than in the remaining areas 9 of the strip which were not provided with decorative or identification elements. A maximum embossing profile of 4 m results from this.