FOIL PACKAGING

Abstract

A foil packaging for soft food masses includes a container film shape-formed into the form of an open container and a lidding film which is sealed onto the container film closing the container with a lid. The container film and lidding film are multi-layered and one of the layers is an aluminum foil, which is optionally pre-lacquered and if desired printed on and lacquer-coated on one side. The aluminum foil of the container film and the lidding film is coated with a polymer and a hot-sealing lacquer is provided on the polymer layer of the container film. The polymer, optionally coated with hot-sealing lacquer, may be situated on the sealing side of the aluminum foil of the lidding film, and a corrosion protection layer, if desired in the form of a polymer, is provided on the other side of the aluminum foil. Alternatively, the aluminum foil of the lidding film may be coated on the sealing side with hot-sealing lacquer and the polymer layer, optionally coated with hot-sealing lacquer, is situated on the other side of the aluminum foil.

Description

The invention relates to a film-type form of packaging for soft foodstuffs, having a container film shaped into the form of an open container featuring a hot-sealing layer and a lidding film which is sealed onto the hot-sealing layer of the container film and closes the container with a lid, whereby the container film and the lidding film are multi-layered and one of the layers is an aluminium foil which is optionally pre-lacquered on one side and if desired is printed on and lacquered over.

Known are film-type forms of packaging made of coated aluminium foils for packaging small portions of soft cheese or melting cheese in the form of cubes, triangles, tetrahedrons and other designs suitable for packaging small portions of soft contents, such as are served as snacks along with aperitifs. In a packaging machine the cheese is poured in portions in a molten or pasty state into open containers of shaped container film. After laying lids of lidding film onto the contents in the open container, the lids are tightly hot-sealed onto the container along a peripheral strip of container edge which is bent inwards towards the lid.

Up to now the kinds of aluminium foils employed for the film-type forms of packaging mentioned above were coated with a lacquer-type primer to protect aluminium from corrosion and to improve adhesion of the hot-sealing lacquer. With this measure, however, it is not always possible to avoid unattractive surface corrosion of the aluminium foil due to migration of corrosion-promoting substances in the cheese through the lacquer layers.

The object of the present invention is to provide a film-type form of packaging of the kind mentioned at the start in which the aluminium foil is effectively protected against corrosion and good bonding with hot-sealing lacquers is provided.

That objective is achieved by way of the invention in that the aluminium foil of the container film and the lidding film is coated with a polymer layer, whereby the hot-sealing layer is situated on the polymer layer on the container film and, alternatively,

• a) the polymer, optionally coated with hot-sealing lacquer, is situated on the sealing side of the aluminium foil of the lidding film, and a corrosion protect-ion layer, if desired in the form of an polymer, is provided on the other side of the aluminium foil, or
• b) the aluminium foil of the lidding film is coated on the sealing side with hot-sealing lacquer and the, optionally hot-sealing lacquer coated, polymer layer is situated on the other side of the aluminium foil.

The polymer layer is preferably a ionomer layer. The essential advantage of the ionomer layer over a conventional lacquer-based primer is that very thin films can be produced that exhibit high mechanical stability and effectively protect the underlying aluminium foil against corrosion. Further, the thin ionomer layer forms an excellent primer for hot-sealing layers.

The hot-sealing lacquer is advantageously a low-temperature sealing lacquer, i.e., a sealing layer that seals already at temperatures from 50° C. upwards.

The aluminium foil of the container film and the lidding film is preferably coated with 1 to 10 g/m², in particular 2 to 8 g/m² of polymer.

The thickness of the aluminium foil of the container film and the lidding film is preferably about 5 to 15 μm, in particular about 6 to 12 μm.

The polymer is preferably a polyolefin, such as polyethylene or polypropylene, or a ionomer, such as an ethylene/acrylic acid/zinc or sodium ionomer or a zinc-acrylate ter-ionomer. A suitable ionomer is the product known by the trade name Surlyn 1857.

The film-type form of packaging according to the invention is particularly suitable for packaging soft foodstuffs, especially in the form of blocks or cubes. Suitable soft foodstuffs, apart from soft cheese and melting cheese are e.g. sweets.

The aluminium foil of the film-type packaging according to the invention shows excellent dead fold properties which are necessary with packaging of the aforementioned kind.

The film-type packaging according to the invention may be provided with opening aids known in the art, such as tear strips or threads, or by a film orientated in the tear direction.

Further advantages, features and details of the invention are revealed in the following description of preferred exemplified embodiments and with the aid of the drawing, which shows schematically in

FIG. 1 a perspective view of a cube-shaped film-type packaging;

FIG. 2 a vertical section through the film-type packaging shown in FIG. 1 along line I-I, showing a first version of a lid;

FIG. 3 a vertical section through the film-type packaging shown in FIG. 1 along line I-I, showing a second version of a lid;

FIG. 4 a cross-section through the container film of the film-type packaging shown in FIG. 2;

FIG. 5-8 a cross-section through various versions of lidding films for the container film in FIG. 4;

FIG. 9 a cross-section through the container film of the film-type packaging shown in FIG. 3;

FIG. 10 a cross-section through a lidding film for the container film shown in FIG. 9.

Shown in FIG. 1 is a cube-shaped film-type packaging 10 for soft contents 18 such as e.g. melting cheese or soft cheese in the form of aperitif cubes comprising a container 13 with a base 11 and side walls 12 projecting up therefrom, the free edges of which are folded inwards at an angle of 90° forming a peripheral sealing edge 14. A lid 16, 20 is hot-sealed onto the sealing edge 14 from the inside of the packaging.

The film-type packaging 10 shown in FIG. 2 features a lid 16 with folded over, flat quadratic lid area. The hot-sealing—indicated by the arrows—of the lid 16 onto the sealing edge 14 of the container 13 takes place with appropriate sealing tools from above and from the sides facing the contents 18 which, at an earlier stage, are poured portion-wise in the fluid state into the container 13 which is pre-formed on a packaging machine out of a container film 30 and is open at the top.

In principle it is possible to reach sealing with the hot contents 18 at filling without sealing tools already at a temperature of the contents from 50° C. upwards by a suitable choice of a low-temperature lacquer adapted to the filling temperature of the contents.

In the version of film-type packaging 10 shown in FIG. 3 the lid 20 features a quadratic base area 22 with edges that have been folded twice about an angle of 90° upwards and inwards with the cut edges 23 facing inwards, with the result that sealing faces 24 are produced parallel to the side walls 12 of the container 13 and sealing faces 26 are produced parallel to the sealing edge 14 of the container 13. As in the example shown in FIG. 2, the hot sealing—indicated by arrows—of the lid 20 onto the sealing edge 14 of the container 13 takes place with corresponding sealing tools from above and from the sides facing the contents 18 which, at an earlier stage, are poured portion-wise in the fluid state into the container 13 which is pre-formed on a packaging machine out of a container film 30 and is open at the top.

A container film 30 with an aluminium foil 34 shown in FIG. 4 features in sequence, on the side of the aluminium foil 34 facing out from the packaging 10, a pre-lacquer layer 42, printing 44 and, on the outside, an outer protective lacquer layer 46.

On the sealing side 18 facing the contents 18 the aluminium foil 34 is coated with an ionomer deposited by extrusion coating. Here, the ionomer layer 36 serves both as primer for a low-temperature hot-sealing layer 38a and as a corrosion protection layer.

A first version of lidding film 32 for the production of the lid 16 features—as shown in FIG. 5—an aluminium foil 34 the sealing side of which is coated with a hot-sealing lacquer 38. The side of the aluminium foil 34 facing the contents 18 is coated with an ionomer 36 deposited by extrusion coating. The ionomer layer takes on the function of a corrosion protection layer.

In a combination of the container film 30 in FIG. 4 and the lidding film 32 in FIG. 5 the sealing takes place in the region of the sealing edges 14 between the low-temperature hot-sealing layer 38a of the container film and the hot-sealing layer 38 of the lidding film 32.

A second version of lidding film 32 for manufacture of the lid 16 features—as shown in FIG. 6—an aluminium foil 34, the sealing side of which is coated with a hot-sealing lacquer 38. The side of the aluminium foil facing the contents 18 is coated with an ionomer 36 deposited by extrusion coating. Here, the ionomer layer serves as primer for a low-temperature hot-sealing layer 38a and as a corrosion protection layer.

In a combination of the container film 30 in FIG. 4 and the lidding film 32 in FIG. 6 the sealing takes place in the region of the sealing edges 14 between the low-temperature hot-sealing layer 38a of the container film 30 and the hot-sealing layer 38 of the lidding film 32. Further sealing takes place between the low-temperature hot-sealing layer 38a of the container film 30 and the low-temperature hot-sealing layer 38a of the lidding film 32 in the region of the side walls 12 of the container 13. Depending on the temperature, the sealing temperature of a low-temperature hot-sealing lacquer lies approximately between 50 and 120° C.

A third version of lidding film 32 for manufacture of the lid 16 features—as shown in FIG. 7—an aluminium foil 34, the sealing side of which is coated with an ionomer 36 deposited by extrusion coating. The ionomer layer 36 serves here as primer for a hot-sealing layer 38. The side of the aluminium foil facing the contents 18 is provided with a conventional corrosion protection layer 40.

In a combination of the container film 30 in FIG. 4 and the lidding film 32 in FIG. 7 the sealing takes place in the region of the sealing edges 14 between the low-temperature hot-sealing layer 38a of the container film 30 and the hot sealing layer 38 of the lidding film 32.

A fourth lidding film 32 for the manufacture of the lid 16 features—as shown in FIG. 8—an aluminium foil 34, the sealing side of which is coated with an ionomer deposited by extrusion coating. The side of the aluminium foil facing the contents 18 is coated with a conventional corrosion protection lacquer 40.

In a combination of the container film 30 in FIG. 4 and the lidding film 32 in FIG. 7 the sealing takes place in the region of the sealing edges 14 between the low-temperature hot-sealing layer 38a of the container film 30 and the ionomer layer 36 of the lidding film 32.

A further container film 30 with an aluminium foil 34, shown in FIG. 9, features printing 44 on the side of the aluminium foil 34 facing out from the film-type packaging 10.

On the sealing side facing the contents 18 the aluminium foil 34 is coated with an ionomer 36 deposited by extrusion coating. The ionomer layer 36 serves here as primer for a hot-sealing layer 38

A lidding film 32 used to make the lid 20 features—as shown in FIG. 10—an aluminium film 34 which is coated on the side facing the contents with an ionomer 36 deposited by extrusion coating to provide a primer for a hot-sealing lacquer 38. By folding the edges of the lid 20 twice about an angle of 90°, upwards and inwards, the side coated with the hot-sealing lacquer 38 forms the sealing areas 26 facing the container film 30. On the side of the lidding film 32 facing the contents 18 the ionomer layer 36 takes on the additional function of a corrosion protection layer.

In a combination of the container film 30 in FIG. 9 and the lidding film 32 in FIG. 10 the sealing takes place in the region of the sealing areas 26 and the sealing areas 24 of the lid 20 between the hot-sealing layer 38 of the container film 30 and the hot-sealing layer 38 of the lidding film 32.

Further sealing occurs between the ionomer layer 36 of the surrounding edge forming the sealing areas 26 and the ionomer layer of the underlying base area 22 of the lid 20, and between the hot sealing layer 38 of the container film 30 and the ionomer layer 36 of the underlying lidding layer 32 in the part of the sealing edge 14 of the container 13 projecting beyond the sealing areas 26 of the lid 20.

In the examples shown in FIGS. 4 to 8 the thickness of the aluminium foil lies preferably between approximately 5 and 9 μm, in particular between approximately 6 and 8 μm, and in the examples shown in FIGS. 9 and 10, preferably between approximately 9 and 15 μm, in particular between approximately 11 and 13 μm. The thickness of the ionomer layer 36 in all examples shown amounts to a weight per unit area of approximately 1-10 g/m², in particular approximately 2-8 g/m².

Instead of an extrusion coating layer, the ionomer layer 36 may also be deposited on the aluminium foil 34 in an aqueous emulsion and subsequently dried at a temperature of about 80° C. to form a film. A suitable ionomer is e.g. Surlyn 1857.

For example, hot-sealing lacquers of acrylic or vinyl-acetate basis may be employed to produce the hot-sealing layer 38.

Claims

1. (canceled)

2. (canceled)

3. (canceled)

4. (canceled)

5. (canceled)

6. (canceled)

7. A foil packaging for soft foodstuffs, comprising a container film shaped into the form of an open container featuring a hot-sealing layer and a lidding film that is sealed into the hot-sealing layer of the container film and closes the open container with a lid, wherein the container film and the lidding film are multi-layered and include a layer which is an aluminum foil, wherein:

the aluminum foil is coated with a polymer to provide a polymer layer, whereby the hot-sealing layer is situated on the polymer layer of the container film and, alternatively:

a) the polymer layer is situated on the sealing side of the aluminum foil of the lidding film and a corrosion protection layer is provided on the other side of the aluminum foil; or

b) the aluminum foil of the lidding film is coated on the sealing side with a hot-sealing lacquer and the polymer layer is situated on the other side of the aluminum foil.

8. A foil packaging according to claim 7, wherein the aluminum foil of the container film and the aluminum foil of the lidding film each independently exhibit a thickness of 5 to 15 μm.

9. A foil packaging according to claim 7, wherein the aluminum foil of the container film and the aluminum foil of the lidding film each independently exhibit a thickness of 6 to 11 μm.

10. A foil packaging according to claim 7, wherein the aluminum foil of the container film or the lidding film or both the container film and the lidding film is pre-lacquered on one side.

11. A foil packaging according to claim 7, wherein the aluminum foil of the container film or the lidding film or both the container film and the lidding film is printed on and lacquered over.

12. A foil packaging according to claim 7, wherein the polymer layer is coated with a hot-sealing lacquer.

13. A foil packaging according to claim 7, wherein the corrosion protection layer is in the form of a polymer.

14. A foil packaging according to claim 7, wherein the aluminum foil of the container film or the lidding film or both the container film and the lidding film is coated with polymer in a weight per unit area of about 1-10 g/m2.

15. A foil packaging according to claim 7, wherein the aluminum foil of the container film or the lidding film or both the container film and the lidding film is coated with polymer in a weight per unit area of about 2-8 g/m2.

16. A foil packaging according to claim 7, wherein the polymer is a polyolefin.

17. A foil packaging according to claim 7, wherein the polymer is a polyethylene or polypropylene.

18. A foil packaging according to claim 7, wherein the polymer is an ionomer.

19. A foil packaging according to claim 7, wherein the hot-sealing lacquer is a low-temperature sealing lacquer.