EP3191312B1 - Device for partial embossing of sealing lids and method for partial embossing of sealing lids - Google Patents

Description

The present invention relates to a device for partially embossing sealing plates and a method for partially embossing sealing plates.

Nowadays, containers for food are often tightly closed with sealable lids. This is particularly true for foods that are consumed directly from the container. The containers are usually formed directly in a device, filled with the intended product and then sealed with a sealing plate. In another process, prefabricated containers are filled in a machine and sealed with a sealing plate. Such devices are known as so-called “fill-seal” machines (FS machines). The sealing plates required to close the container are usually prefabricated sealing plates that are manufactured in large numbers and stored or transported in stacks. These sealing boards are often made of aluminum or a laminate that includes a layer of aluminum. At the food bottler, the sealing plates are fed to the above-mentioned fill-seal machines using a feed device, for example, and sealed directly onto the edge of the filled container. The sealing plates, which are often additionally printed and punched out according to the contours of the container, are stacked. Since the sealing plates are transported and delivered in stacks, the sealing plates must be unstacked again using the feed device and fed individually to a filled container. However, stacking the flat and smooth sealing plates causes them to stick together in the stack with considerable adhesion (glass plate effect). However, the orderly unstacking of the sealing plates is difficult to control and it is not guaranteed that the sealing plates are individually unstacked and each fed to a container or sealed. In order to ensure that individual sealing plates are unstacked, it is known, for example, to emboss the sealing plates. Although this improves unstackability, it has a detrimental effect on possible unstacking Printing on the seal plate affects its appearance and makes it difficult to read parts of the printing, e.g. content information. Methods are also known in which the embossing is at least partially reversed by flattening in order to obtain a print area with little embossing. However, it is not possible to completely undo an embossing and achieve a smooth surface again.

Out of EP 0 960 024 a method for only partially embossing lids is known. The partial embossing of the lids is achieved by means of reading marks on the film material from which the lids are punched out. These reading marks allow correct positioning between the printed parts of the foil and the parts of the foil to be embossed or the embossing tools.

In EP 1 790 470 A method for partially embossing lids is described, whereby the geometric position of the embossing tool relative to the film web is adjustable. The partial embossing is carried out in such a way that successive lids are not embossed congruently and is preferably only applied to every second lid.

In DE 1 940 970 Stackable closure lids made of a coated film and their production are described. The production takes place using a punching and an embossing tool, the latter being rotatable.

WO 2009/097961 A1 discloses a lid made of a carrier material, an inward-facing sealing layer made of a sealing wax printed on the carrier material, based on a container to which the lid is used, for closing the container having a shoulder, the inward-facing side of the carrier material being the sealing layer in the form of a printed image corresponding to the shoulder of the container and within the area delimited by the sealing layer a printed pattern made of a sealing wax or polymer-containing lacquer is printed onto the carrier material, as well as a method for producing the lid.

An object of the present invention is to provide a device and a method for producing partially embossed sealing plates that can be further processed easily and without problems.

The expressions partial embossing of sealing plates and partial embossing of sealing plates are used synonymously in the present case and are understood as embossing a part of the surface of the sealing plate.

The object is achieved by a device according to claim 1 and a method according to claim 11. Advantageous embodiments of the invention are described in the dependent claims.

A device according to the invention for partially embossing deep-drawn or flat sealing plates that are punched out of a foil strip comprises an embossing tool and a punching tool. The current application discloses an embossing tool comprising two half tools, a male die and a die. This is on the

The desired deep-drawn contour or three-dimensional relief is depicted using mechanical processes. The patrix has the three-dimensional relief in a raised and mirror-image form. The counterpart of the patrix, the die or stamp, has the three-dimensional relief in the correct and recessed form. On the contoured side of the male part, three-dimensional elements are arranged in an outer area and in a central area. The male and female molds are rotatably mounted in their spatial position about an axis A that is essentially perpendicular to the film strip.

In the device according to the invention, the embossing and punching tools are combined in one tool. The film web is gradually moved in the transport direction or machine direction of the device. The embossing tool arranged in front of the punching tool creates the desired contour or embossing in the sealing plate by means of a lifting movement by deep drawing. Before the next lifting movement takes place, the film strip is moved in the transport direction via appropriate transport means to such an extent that the film strip or the sealing plate, which is now partially or partially embossed, is on the position of the punching tool comes to rest, where it is punched out of the film strip during the next stroke movement of the punching tool. Since the male mold and the die of the embossing tool are rotatably mounted about an axis A, which is essentially perpendicular to the film strip, a simple rotation of the male die and the die through an angle α about the axis A can be achieved. that no two successive sealing plates that come together in a stack after punching out have a congruent embossing. The male and female dies of the embossing tool are rotated synchronously and in the same direction through the same angle α. This avoids undesirable sticking of the partially embossed sealing plates together during unstacking in a simple and advantageous manner. By rotating the male and female dies with respect to the film strip between each stroke movement, the desired inequalities in coverage are reliably achieved. The immediately adjacent arrangement of the embossing and punching tools also results in greater precision in the partial embossing and the punched out contour of the sealing plate. Furthermore, the only partial embossing of the sealing plate enables a better print image on the sealing plate that is not affected by any embossing.

In the device according to the invention, the embossing tool in turn comprises two half-tools, a male die and, as a second half-tool, an elastic medium. The male part is rotatably mounted in its spatial position about an axis A which is essentially perpendicular to a film strip. The function of the die is taken over by the elastic medium.

The elastic medium is preferably designed in the form of a stamp pad. The circumferential contours of the stamp pad preferably correspond to the circumferential contours of the male die. They are, for example, cylindrical or circular cylindrical. The male part and the elastic medium are precisely aligned with one another, that is, their axes, which are essentially perpendicular to a film strip, are aligned. The elastic medium does not have a three-dimensional relief in a correct and recessed form as a conventional matrix does. This is not necessary due to the elastic medium. The partial surface embossing of the film strip is achieved by exerting a sufficiently large pressure of the elastic medium on the film strip lying between the elastic medium and the male mold. Since the elastic medium does not have three-dimensional relief, it is not necessary that it is rotatably mounted about an axis A that is essentially perpendicular to a film strip. The elastic medium is therefore preferably mounted so that it cannot rotate about the axis A. This results in a structural simplification of the embossing tool.

The elastic medium can have any shape to generate a sufficiently large stamp pressure. The elastic medium preferably has the shape of a stamp pad, the circumferential contours of which correspond to those of the male die.

The elastic medium preferably comprises hard rubber. Other elastic media can also be used, for example plastics, for example elastomers, preferably thermoplastic elastomers.

In a preferred embodiment, the three-dimensional elements are arranged randomly in the outer and central areas. The three-dimensional elements are particularly preferably arranged randomly in the outer area.

In a further embodiment, the three-dimensional elements in the outer area and in the central area of the male part are arranged on circular lines, preferably at regular intervals.

The three-dimensional elements can have different shapes. For example, they can be cylindrical, preferably circular cylindrical, projections that extend essentially vertically away from the surface of the male mold.

In a further preferred embodiment, the individual three-dimensional elements have a different height. This means that the male part has three-dimensional elements, part of which has a first height, while the remaining three-dimensional elements have a second height the first has different heights. It is also possible that there are even more groups of three-dimensional elements, for example having a third and a fourth height.

In another embodiment, the male part is mounted so that it can rotate through an angle α. The angle α corresponds to the central angle of a sector of a circle, which is defined by two adjacent three-dimensional elements.

In a preferred embodiment, the angle α is in a range from 2° to 90°, particularly preferably in a range from 3° to 45° and very particularly preferably in a range from 4° to 15°.

As already stated, the three-dimensional elements can be designed differently and, for example, have different heights. In a preferred embodiment, the three-dimensional elements have a height in the range of two to five times the thickness of the film strip. They particularly preferably have a height in the range of three to four times the thickness of the film strip. All three-dimensional elements can have the same height within the specified ranges or the three-dimensional elements can have two or more different heights. Three-dimensional elements of different heights further reduce the effect of stacked sealing plates sticking to one another.

A typical thickness of films or film strips used for the production of sealing plates according to the invention is in the range from 20 μm to 50 μm, preferably in a range from 24 μm to 40 μm and particularly preferably in the range from 30 μm to 36 μm. Two examples of typical thicknesses for the films used are 25µm and 35µm. From this, the particularly preferred ranges for the height of the three-dimensional elements can be determined, which are three to four times the thickness of the foil tape used. The height of the three-dimensional elements is in the range from 60µm to 200µm, preferably in the range from 72µm to 160µm and particularly preferably in the range from 90µm to 144µm. Accordingly, the ranges corresponding to two to five times the film thickness can be determined for the height of the three-dimensional elements. The height of a three-dimensional element is measured from the film surface, on the side of the film on which the three-dimensional elements rise, to the tip or end face of a three-dimensional element.

In a further preferred embodiment, the area of the male part comprising outer three-dimensional elements borders directly on the edge of the male part. Furthermore, the outer area is arranged concentrically to the central area. The central area also has three-dimensional elements, at least on its outer circumference.

The contour and circumference of the die and the male die of the embossing tool are adapted to that of the sealing plate. The same applies to the contour of the punching tool. In a preferred embodiment, the die and the male die of the embossing tool have a circular contour or a circular circumference.

In a further preferred embodiment, the embossing tool and the punching tool are arranged adjacently and both tools can be operated synchronously.

The method according to the invention for producing partially embossed sealing plates for containers, in particular for food, is carried out on a device described above. A continuous film strip is fed to the device via rollers. The film tape has preferably already been printed beforehand and then wound onto a roll. The continuous foil tape with the The previously printed sealing plates are fed to the embossing tool. The film strip is transported step by step and the film strip stands still between the feed steps. During the standstill, the partial embossing of the sealing plate is created by means of a lifting movement by the embossing tool or its male die. The lifting movement of the embossing tool can also be carried out using the die or the elastic medium. With the following feed step, the foil strip or the now partially embossed sealing plate is moved forward in the transport direction and positioned above the punching tool. With the next stroke movement of the punching tool, the partially embossed sealing plate is punched out and stacked via a collecting channel. Between two lifting movements of the punching tool, the male die and the die of the embossing tool are rotated by at least an angle α about an axis A that is essentially perpendicular to the film strip.

The embossing tool and the punching tool are preferably operated synchronously, which means that with each stroke movement of the punching tool, a partial surface embossing of the film strip or the sealing plate that has not yet been punched out is carried out.

If the method is carried out using the device according to the invention, the embossing tool of which comprises two half-tools, a male die and an elastic medium, the rotational movement of the elastic medium, which takes over the function of the die, is preferably eliminated. In this case, it is advantageously sufficient if the male die is rotated by an angle α between two stroke movements of the punching tool.

In a preferred embodiment, the angle α is in a range from 2° to 90°, particularly preferably in a range from 3° to 45° and very particularly preferably in a range from 4° to 15°. In a current embodiment, the angle α = 4.39°. The male die is therefore rotated by the angle of rotation of 4.39° between two stroke movements. Advantageously the angle α is small so that the rotation of the male die does not limit the speed in the process.

In a preferred embodiment, the male mold and the female mold are rotated back by an angle α in the opposite direction of rotation between two lifting movements after a first rotation by the angle α.

Fig. 1

eine Aufsicht auf eine Patrize;

Fig. 2

eine Aufsicht auf eine Patrize, wobei diese in zwei verschiedenen Positionen zu sehen ist;

Fig. 3

einen Querschnitt durch einen Ausschnitt einer Patrize.

The device according to the invention is explained in more detail using an exemplary embodiment shown in the drawings. It shows purely schematically:

Fig. 1

a supervision of a patrician;

Fig. 2

a top view of a male mold, which can be seen in two different positions;

Fig. 3

a cross section through a section of a male part.

Figure 1 shows a top view of a male die 1 of an embossing tool. The male part 1 is rotatably mounted about an axis A and has an outer area 3 and a central area 5. Both the outer area 3 and the central area 5 include three-dimensional elements 7. In the embodiment shown, the three-dimensional elements 7 are arranged in the outer area 3 on two concentric circular lines. The central area 5 also has three-dimensional elements 7 arranged on its circular circumference. However, the area between the outer area 3 and the central area 5 is free of three-dimensional elements 7. The contour of the sealing plate 9 is also shown, the circumference of which extends practically to the edge of the male part 1.

Figure 2 shows the patrix 1 Figure 1 in two different rotation positions. The male mold 1 was moved from the first rotational position by an angle α into the two Rotation position twisted. The three-dimensional elements 7 arranged on two concentric circular lines in the outer region 3 of the male mold 1 are arranged offset on the two circular lines, so that after a rotation of the male mold 1 through an angle α about the axis A, which is essentially perpendicular to the male mold, one three-dimensional element is formed 7 of the inner concentric circular line comes to lie at the angular position at which a three-dimensional element 7 of the outer concentric circular line was located before the rotation and vice versa.

Figure 3 shows a cross section through a section of a male mold 1 with three-dimensional elements 7, 7 'and 7" with different heights.

Claims (12)

1. Device for the partial embossing and punching of sealing lids from a film/foil strip, having an embossing tool comprising two half-tools, a male mould (1) and an elastic medium, and a punching tool, characterized in that the male mould (1) has three-dimensional elements (7) which are disposed in an outer region (3) and in a central region (5), and in that the male mould (1) in terms of the spatial orientation thereof is mounted so as to be rotatable about an axis A which is substantially perpendicular to a film/foil strip.
2. Device according to Claim 1, characterized in that the elastic medium comprises hard rubber.
3. Device according to one of the preceding claims, characterized in that the three-dimensional elements (7) are irregularly disposed.
4. Device according to one of Claims 1 to 3, characterized in that the three-dimensional elements (7) are disposed on circular lines, preferably at regular spacings.
5. Device according to one of the preceding claims, characterized in that the three-dimensional elements (7) have different heights.
6. Device according to one of the preceding claims, characterized in that the male mould (1) is mounted so as to be rotatable by an angle α, wherein the angle α corresponds to the central angle of a circle sector defined by two three-dimensional elements (7) that lie next to one another.
7. Device according to one of the preceding claims, characterized in that the three-dimensional elements (7) have a height in the range of twice to five times, preferably thrice to four times, a thickness of the film/foil strip, wherein the film/foil strip has a thickness in the range from 20 um to 50 um, preferably in a range from 24 µm to 40 µm, and particularly preferably in the range from 30 um to 36 µm.
8. Device according to one of the preceding claims, characterized in that the outer region (3) of the male mould (1) that comprises three-dimensional elements (7) is contiguous to the periphery of the male mould (1) and disposed so as to be concentric with the central region (5) comprising three-dimensional elements (7).
9. Device according to one of the preceding claims, characterized in that the male mould (1) of the embossing tool is circular.
10. Device according to one of the preceding claims, characterized in that the embossing tool is disposed so as to be adjacent to the punching tool, and in that the two tools are able to be operated synchronously.
11. Method for producing sealing lids for containers, which are embossed over a partial area and optionally printed, carried out on a device according to one of Claims 1 to 10, wherein the sealing lids are punched from a film/foil strip which is embossed over a partial area, characterized in that the male mould (1), which in terms of the spatial orientation thereof is mounted so as to be rotatable about an axis A which is substantially perpendicular to the film/foil strip, is rotated by at least an angle α between two stroke movements of the punching tool.
12. Method according to Claim 11, characterized in that the male mould (1) after one rotation by the angle α between two stroke movements is rotated back by an angle α in the opposite direction of rotation.

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