Note: Descriptions are shown in the official language in which they were submitted.
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S p e c i f i c a t i o n 2~9418
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Effem GmbH, Eitzer Landstrasse, 2810 Verden/Aller
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Bowl-shaped Package
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The invention concerns a bowl-shaped package, in particular for holding
food portions which must be sterilized, such as pet food or the like,
with a lower part which is open at the top and made of sheet metal, such
as aluminum or steel, in the shape of a bowl, a hollow cylinder or the
like, on the upper edge of which a circular sealing edge is provided
which is made in one piece with the lower part, the circular sealing
surface of which, directed upward, runs essentially parallel to the base
surface of the lower part, a continuous inner coating covering the
inside of the lower part as well as the sealing surface thereof is
provided as protection against corrosion which prevents the package
content from coming in contact with the sheet metal of the lower part,
and a sealing foil made of metal foil, paper or the like, which is
furnished with a sealing foil coating on its underside facing the lower
part, whereby the material for the inner coating and the sealing foil
coating is selected in such a way, using a plastic and a sealing wax
component, such as polypropylene, poiyethylene, polyethylene
terephthalate or polycarbonate or a sealing wax compatible therewith,
that, when the sealing foil is pressed onto the sealing edge in a ~
sealing tool or the like using pressure and heat, a sealing connection -
results between the sealing foil and the lower part which is essentialiy
impermeable to gas and moisture and can be sterilized.
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Bowl-shaped packages of this type, e.g. for small portions of pet food
for dogs or cats, are known. In this case, the lower part usually
consists of a cùpped aluminum bowl, whereas the sealing foil can, for
example, consist of a very thin aluminum foil. To prevent corrosion,
the lower part can be lined on the inside with a plastic film or a
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plastic foil of the above-noted type, as a result of which it is
prevented that the package content comes into direct contact with the
corrosion-sensitive sheet metal of the lower part, which can e.g. also
~ be an especially thin steel plate. The sealing foil coating consists of
a sealing wax, which is applied in flat layers to the sealing foil and
ensures that the sealing foil is sealed with the lower part so as to be
impermeable to gas or fluids by pressing on the sealing edge of the
- lower part using appropriate pressure and appropriate heat.
Bowl-shaped packages of this type have proved quite successful.
However, it has been found to be disadvantageous that the choice of
material for the sealing foil could not as yet be satisfactorily solved.
This is due to the fact that the sealing foil is covered, in
conventional bowl-shaped packages, with a very thin sealing wax layer on
its side facing the lower part and this layer cannot, for its part,
absorb any mechanical stresses in the foil plane and it must also be
made so as to be relatively tear-resistant as well as flexible and
rollable. As a result of this, the possible choices of material are
restricted since neither especially thin e.g~ aluminum foils can be used
which could otherwise tear easily when transported or even at the point
of sale when the sealing foil is subjected to e.g. an impact stress, nor
can any relatively inexpensive materials be used, such e.g. paper or the
like.
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It is the object of the invention to further develop the conventional
bowl-shaped package in such a way that, while retaining the ability to
sterilize, a greater flexibility is attained with respect to the choice
of material for the sealing foil, whereby the bowl-shaped package should
be sturdy and dependable when used.
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` According to the invention, this object is solved thereby that the inner
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coating of the lower part consists of a sealing wax layer and the
sealing foil coating consists of a plastic foil.
It can thereby be provided that the sealing foil coating is applied to
the inner surface and the sealing edge of the lower part as molten or
solvent film.
It can also be provided, according to the invention, that the sealing
foil coating consists of a uniaxially or multiaxially (highly) stretched
plastic material.
The invention is based on the surpising realization that it is possible
to solve the object of the invention by shifting the function of the
plastic foil, which is used as a corrosion coating for the lower part in
the prior art and can merely "act out" its corrosion-resistant
properties without using the additional inherent property of plastic
foil, namely its viscosity and high mechanical stability, to a more
proper position, namely, by developing it as a sealing foil coating,
whereas the sealing wax, which was thusfar provided in the prior art on
the sealing foil, is used as inner protective coating for the lower
part.
In the invention, the sealing wax which is not in a position to assume
mechanical functions thus serves two functions as inner coating for the
lower part, namely, on the one hand, to ensure a reliable protection
against corrosion of the lower part, in addition, however, also, as in
the prior art, to enable a reliable sealing in connection with the
plastic foil, whereas the plastic foil, as sealing foil coating, brings
to bear its properties which are not used in conventional bowl-shaped
packages, namely viscosity and high lateral mechanical strength. Since,
as a result, the actual sealing foil material is relieved, for the
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greatest part, of the functions of mechanical viscosity and lateral
strength, the sealing foil material, for example then the aluminum or
steel sheet used, can be made essentially thinner than in conventional ~ -
bowl-shaped packages, including having all the cost advantages
associated therewith. Also, materials can be used which could thusfar
not be used, such as e.g. paper or the like, i.e. materials having only
slight mechanical strength.
On the whole, it is hereby made possible to create an essentially less
expensive bowl-shaped package which possesses, moreover, improved
strength properties with respect to the sealing foil.
Additional features and advantages of the invention can be seen in the
following description in which an embodiment of the invention is
explained in greater detail with reference to the schematic drawing.
The drawing, which consists of only one figure, thereby shows a `
bowl-shaped package according to the invention, in a vertical section
through the longitudinal axis.
As can be seen in the drawing, the bowl-shaped package of the invention
has, in the embodiment shown there, a lower part 10 which here consists
of sheet steel with a thickness of O.l mm and is produced in a cupping
process. The lower part 10 is, on its inner surface, including a
sealing edge extending essentially parallel to its base surface, coated
with an inner coating 12 of sealing wax which is made so thick that the
sheet steel of the lower part 10 is protected against corrosion and a
reliable seal is also made possible. A sealing foil 14, consisting of
very thin aluminum foil, is provided on its lower side with a sealing
foil coating 16 in the form of a polypropylene foil. By means of a
sealing tool, the sealing foil 14 can be joined in a known manner with
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the lower part 10, along the sealing edge, by using pressure and heat so
as to be impermeable to gas and fluids, whereby it can be ensured, by
appropriately selecting the sealing wax for the inner coating 12 and the
material for the sealing foil coating 16, that the filled and sealed
package can be sterilized.
Of course, the basic idea of the invention, to provide the
corrosion-sensitive lower part with an inner coating of sealing wax,
simultaneously serving as a corrosion layer, to furnish, on the other
hand, the sealing foil 14 covering the lower part with a sealing foil
layer which can be mechanically stressed and is compatible with the
sealing wax of the inner coating 12 of the lower part 10 in the form of r
a mechanically stressable plastic foil, cannot only be used in
bowl-shaped packages of the above described type but also e.g. in
can-like containers and the like.
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The features of the invention disclosed in the above description, in the
- drawing and in the claims can be essential individually or in any
combination desired for implementing the invention in its various
embodiments.
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