FILM-TYPE PACKAGING

EMBALLAGE PELLICULE

English Abstract

Film-type packaging for soft foodstuffs comprises a container film shape-
formed
into the form of an open container (13) and a lidding film which is sealed
onto
the container film closing the container (13) with a lid (16). The container
film
and the lidding film are multi-layered and one of the layers is an aluminium
foil
which is optionally pre-lacquered and if desired printed on and lacquer coated
on one side. The aluminium 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. 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 protection layer, if desired in the form of a
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.

French Abstract

L'invention concerne un emballage pelliculé destiné à des pâtes alimentaires molles, composé d'une pellicule de contenant formée en tant que contenant ouvert (13) et d'une pellicule de couvercle scellée contre la pellicule de contenant, refermant le contenant (13) avec un couvercle (16). La pellicule de contenant et la pellicule de couvercle sont conçues en plusieurs couches et une des couches est une pellicule d'aluminium éventuellement pré-vernie ou imprimée ou revernie unilatéralement. La pellicule d'aluminium de la pellicule de contenant ou de la pellicule de couvercle est revêtue d'un polymère et la couche polymère de la pellicule de contenant comporte une couche de thermoscellage. De façon sélective, (a) le polymère éventuellement revêtu de vernis de thermoscellage est disposé sur la pellicule d'aluminium de la pellicule de couvercle, sur le côté de scellage, et une couche anti-corrosion éventuellement composée d'un polymère est disposée sur l'autre côté de la pellicule d'aluminium; et (b) la pellicule d'aluminium de la pellicule de couvercle est revêtue de vernis de thermoscellage sur le côté de scellage, et la couche polymère éventuellement revêtue de vernis de thermoscellage est disposée sur l'autre côté de la pellicule d'aluminium.

Claims

9
Claims
1. Foil-type packaging for soft foodstuffs, having a container film (30)
shaped
into the form of an open container (13) featuring a hot-sealing layer (38) and
a lidding film (32) that is sealed onto the hot-sealing layer (38) of the
container film (30) and closes the container (13) with a lid (16,20), whereby
the container film and the lidding film (32) are multi-layered and one of the
layers is an aluminium foil (34) which is optionally pre-lacquered on one side
and if desired is printed on and lacquered over,
characterised in that,
the aluminium foil (34) of the container film (30) and the lidding film (32)
is
coated with a polymer (36), whereby the hot-sealing layer (38) is situated on
the polymer layer (36) of the container film (30) and alternatively,
a) the polymer (36), optionally coated with hot-sealing lacquer (38), is
situated on the sealing side of the aluminium foil (34) of the lidding film
(32), and a corrosion protection layer (40), if desired in the form of a
polymer, is provided on the other side of the aluminium foil (34), or
b) the aluminium foil (34) of the lidding film (32) is coated on the sealing
side with hot-sealing lacquer (38) and the, optionally hot-sealing lacquer
(38) coated, polymer layer is situated on the other side of the aluminium
foil (34).
2. Foil-type packaging according to claim 1, characterised in that the
aluminium
foil (34) of the container film (30) and the lidding film (32) exhibit a
thickness
of 5 to 15 µm, preferably 6 to 11 µm.
3. Film-type packaging according to claim 1 or 2, characterised in that the
aluminium foil (34) of the container film (30) and the lidding film (32) is

coated with polymer (36) the weight per unit area of which is approximately
1- 10 g/m2, in particular approximately 2 - 8 g/m2.
4. Film-type packaging according to one of the claims 1 to 3, characterised in
that the polymer (36) is a polyolefin, preferably a polyethylene or a
polypropylene.
5. Film-type packaging according to one of the claims 1 to 3, characterised in
that the polymer (36) is a ionomer.
6. Film-type packaging according to one of the claims 1 to 5, characterised in
that the hot-sealing lacquer (38) is a low-temperature sealing lacquer.

Description

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Film-type Packaging
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.

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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 pm, in particular about 6 to 12 pm.
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

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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 afore-
mentioned 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 figure 1
along line I-I, showing a fist version of a lid;
Fig. 3 a vertical section through the film-type packaging shown in figure 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 figure 2;
Fig. 5-8 a cross-section through various versions of lidding films for the
container film in figure 4;

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Fig. 9 a cross-section through the container film of the film-type
packaging shown in figure 3;
Fig. 10 a cross-section through a lidding film for the container film shown
in figure 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 figure 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 figure 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

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of the container 13. As in the example shown in figure 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
5 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 figure 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 figure 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 figure 4 and the lidding film 32
in
figure 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 figure 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

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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 figure 4 and the lidding film 32
in
figure 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 figure 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 figure 4 and the lidding film 32
in
figure 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
figure 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 figure 4 and the lidding film 32
in
figure 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

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ionomer layer 36 of the lidding film 32.
A further container film 30 with an aluminium foil 34, shown in figure 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 figure 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 figure 9 and the lidding film 32
in
figure 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 figures 4 to 8 the thickness of the aluminium foil
lies

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8
preferably between approximately 5 and 9 pm, in particular between
approximately 6 and 8 pm, and in the examples shown in figures 9 and 10,
preferably between approximately 9 and 15 pm, in particular between
approximately 11 and 13 pm. 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
deposit-
ed 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.

Representative Drawing