Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
CA 02758093 2011-10-06
Sealing disk having a tab
The invention relates to a sealing disk for a container closure for use with a
container
having an opening delimited by a circumferential edge, in which the sealing
disk
comprises several layers having an edge, of which a group of lower layers
tightly
closes the opening of the container prior to the initial opening of the
container, in
which the group of lower layers can be sealed by means of a sealing layer onto
the
circumferential edge of the opening, in which the group of lower layers can be
joined
in a detachable manner to a group of upper layers of the sealing disk, in
which the
opening of the container can then be closed again temporarily by the group of
upper
layers, in which the sealing disk has at least one gripping tab, in which the
gripping
tab is formed only by one or several of the layers from the group of lower
layers, and
in which the layers forming the gripping tab project over the edge of the
other layers
flatly by the surface of the gripping tab.
Containers serve for receiving contents, for example, for taking up liquids or
powder-
form food products or other substances. Containers have an opening or a mouth
part. It is frequently desired or even necessary to close this container mouth
part with
a disk-shaped seal, which tightly seals the content against external
influences.
There are several reasons for the requirement of this tight seal. On the one
hand, the
content will be protected against any disruptive influence from the outside,
for
example, against the penetration of water vapor or oxygen; on the other hand,
its
aroma will remain intact. There is another reason in the case of filling with
aggressive
materials: a protection against leakage that is as optimal as possible must be
assured. Finally, an authenticity protection for commercial sales can also be
provided
by such a seal, since the user can immediately discern whether anyone has
previously manipulated the contents of the container.
Additionally, the container opening is then closed with a screw cap or a
similar
element, which provides for the mechanical and stable closing of the container
mouth part outside the disk-shaped seal. The actual disk-shaped seal is a
flexible
thin film in this case. Upon initial use after purchase, the user unscrews the
screw
cap and breaks the film in order to gain access to the content of the
container. After
this, he closes the container again, as long as he has not yet removed the
entire
content. This repeated closing is carried out by now screwing the screw cap--
without
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the film that in the meantime has been broken and removed--onto a
corresponding
counter-thread on the mouth part of the container. The screw closure can
optionally
close the now breached content, possibly for a time span not as long as the
original
closure configuration, but for a time span satisfactory to the user, since he
can now
control it himself.
The film that seals the container contents is introduced by means of induction
sealing, as is known, for example, from EP 0 717 710 B1. For this purpose, a
complete sealing disk is applied, whose lowermost layer forms the sealing
layer. A
metallic second layer, usually comprising aluminum and which serves for the
heat
coupling and transfer during the induction process and optionally forms an
additional
mechanical protection, is applied over the lowermost layer. The second layer
is
solidly combined with the first layer in a well conducting manner,
particularly for heat
transfer. These layers form a group of lower layers. Additional layer-form
components of the sealing disk, which remain in the cap when the screw cap or
other
rotating closure is opened, are then provided above the mentioned aluminum
layer.
These other layers of the sealing disk remaining in the cap form a group of
upper
layers, and are simultaneously those elements that provide for a very good
closure
again upon a repeated closing of the screw cap after the breaking and removal
of the
group of lower layers produced with the initial opening, even though the
authenticity
seal and also the original tightness are lacking after this repeated closing.
A constant problem with such closures that are both reliable and well-proven
is the
initial opening by the user or consumer. During the initial opening, a
breaking of this
film or group of lower layers found on the mouth part of the container by a
knife or
even by the finger of the user, on the one hand, is not always possible or
hygienic for
all container contents, and on the other hand, residues of film are left
behind on the
edge of the opening of the container, which can adversely affect the later
pouring or
shaking out of the container contents.
In order to make the opening process more convenient for the user and also
safer for
further use, the user is provided with a handle or grabbing piece for pulling
off the
film. This grabbing piece can be a folded piece that springs up for the user
to grab
and then pull off the film, as proposed in EP 1 181 211 B1 or WO 00/66453 Al.
It is more common, and for example, is known from DE 39 20 324 Al and EP 0 408
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217 Al, to provide the sealing disk with a gripping tab that springs out,
which then
can be gripped by the user outside the edge of the mouth part of the container
and
be pulled up, so that the entire film is detached from the container edge.
This very simple and convincing design by itself, however, has the
disadvantage that
the gripping tabs are disrupted when the screw cap is screwed on, since they
must
be accommodated in suitable form in the thread and in the screw cap. On the
one
hand, there is little space available there, and, on the other hand, these
gripping tabs
can also adversely affect the function of the screwing process. Conversely,
the
gripping tabs may also be damaged by the screwing process or in the most
unfavorable case, the entire sealing disk can be adversely affected in its
sealing
function.
In order to reduce the problems with the gripping tabs projecting into the
thread of
the screw cap, for example, it is proposed in DE 1 482 575 Al, US Patent
4,722,447
and EP 0 697 345 B1, to equip the sealing disks not with just one, but with
several
outwardly projecting gripping tabs. In this way, a rather symmetric and
thereby
reduced distribution will be achieved. The problem is not solved, of course,
but only
redistributed.
Another approach is selected in proposals from EP 0 668 221 131, GB 2 330 134
A,
JP 2000-191021 A and DE 10 2007 014 084 B3. Here, the sealing disks are
equipped with gripping tabs, in which the thickness of the gripping tab is
less than
the thickness of the other surface regions of the sealing disk. This is
achieved by the
fact that, of the several layers of the sealing disk, only one layer or a few
layers also
form(s) the gripping tabs.
Due to the fact that the tabs of the sealing disk are formed very thin, they
are far
more flexible for accommodating in the remaining empty spaces inside the screw
cap
and the screw-cap thread. The risk of mutual disruption of the individual
elements
when closing the package or also during the opening process is thus
considerably
reduced.
Now, a transfer of these concepts into practice has been successfully carried
out at
least with the production method for these types of sealing disks proposed in
DE 10
2007 014 084 B3.
The idea is also already known from GB 2 330 134 A and JP 2000-191021 A as
well
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as the subsequently-published EP 2 045 194 B1, to form the gripping tab that
is thus
reduced in its thickness and is therefore very thin only from the uppermost
layer or
layers of the group of lower layers and not to allow it to project radially
outward into
the region of the inner thread of the screw cap, but rather, either to bend it
first by
900 upward and then once more by 90 in the direction toward the central point
of the
sealing disk, as in JP 2000-191021 A, and in this way to guide and accommodate
it
in a free space inside the screw cap cover, or, however, as in GB 2 330 134 A
and in
one embodiment of EP 2 045 194 B1, to fold it by 180 and lie it on top of
itself, so
that after the screw cap is unscrewed, the gripping tab lies free for use by
the
consumer.
The design from JP 2000-191021 A has the disadvantage that now, in fact,
although
the gripping tab no longer engages in the thread of the screw cap or of the
container,
it now lies in a region above the upper group of layers and thus in the region
which
will remain in the screw cap when the latter is screwed on, in order to make
possible
a further closing. There is thus now a considerable risk that the gripping tab
will jam
in this region below the screw cap above this so-called "reseal" part and thus
will tear
upon opening and therefore lead to the unwanted disadvantages that are
precisely to
be avoided.
Further practical disadvantages arise in GB 2 330 134 A. Thus, a folding of
the
combination gripping tab that includes the metallic layer on it could disrupt
the
induction sealing properties of the entire combination gripping tab, since a
double
aluminum layer is present in part of the region of the otherwise circular
symmetric
arrangement because of this, and this considerably changes the induction
properties.
The same disadvantages arise in the second embodiment of the subsequently
published EP 2 045 194 B1. This embodiment first folds the gripping tab with
all
layers by 180 on the upper side of the sealing disk and then folds it a
second time
back on itself by 180 . On the one hand, this has the disadvantage that the
sealing
disk possesses a triple thickness in the region of the gripping tab and
thereby is also
mechanically very non-uniform and an adhering to a reseal part, for example,
is
made very difficult, but also in the region of the gripping tab, the aluminum
layer is
formed as a triple layer, and thus also leads to a strong asymmetry of the
induction
properties.
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In one embodiment of GB 2 330 134 A, one attempts to avoid this problem by
moving the metallic layer used for induction into the reseal part, thus into
that part
that is used for the further closure. This is very impractical, since this
aluminum layer
is just not suitable for this purpose, for being used continually on a
container mouth
part with repeated closing and opening actions.
Another disadvantage consists in the fact that when the container and the
container
closures are disposed of, an aluminum layer in a plastic screw cap represents
a
foreign component, which is generally undesired. Plastic and aluminum are to
be
disposed of separately as much as possible. Any remaining aluminum layer in
the
screw caps is thus ecologically undesirable, since it makes recycling
difficult and
thus might encounter rejection by concerned consumers.
Another problem may occur in both the sealing disks according to GB 2 330 134
A
as well as JP 2000-191021 A, and the first embodiment of EP 2 045 194 131 and
also
for other sealing disks, which operate with such back folds of 90 or 180 ,
and, in
fact, this problem may arise due to the fact that a considerable notching
effect occurs
precisely in the edge region between a folded layer and the adjacent, unfolded
layer.
This notching effect leads to a force that tries to detach the different
layers of the
sealing disk from one another.
Grasping the tab could thus lead to the circumstance that the layer provided
with the
tab detaches from the other layers and does not open the container, or does
not
open it as desired, or that parts of the combined layers detach from one
another in
an unanticipated manner or tear.
This behavior when the container is torn open by means of a tab is perceived
by
users as unpleasant and unreliable and is rejected. It should be considered
that a
user then is not only annoyed in this single instance, but his rejection
generally
extends to the corresponding product line of the container packager, and he
may
refrain from the purchase of such goods in future instances, so that the image
of the
producer of the contents of the containers that are thus packaged may also be
tarnished.
The problem of the present invention is thus to propose a sealing disk with
which the
described problems can be avoided as much as possible.
This problem is solved according to the invention with a sealing disk as
initially
CA 02758093 2011-10-06
described, in that the layer of the group of lower layers that lies closest to
the sealing
layer forms the gripping tab, and in that the surface part of this layer
projecting over
the edge of the other layers is folded around the outer edge of all other
layers of the
group of lower layers with the exception of the sealing layer and is applied
flat on top
of the uppermost of the group of lower layers and is covered by the group of
upper
layers, so that the gripping tab can be gripped after detaching the group of
upper
layers in the initial opening of the container.
Alternatively, it is also possible not only to form the layer adjacent to the
sealing layer
in the appropriate form, but also to similarly form several layers lying on
top of one
another directly adjacent to the sealing layer.
The problem presented for the invention can be surprisingly solved in a very
simple
way. Another arrangement of the sequence of the individual layers and a
special
formation of these layers leads to the circumstance that, on the one hand, a
tab is
formed that has a clearly reduced thickness in comparison to the entire
sealing disk
and only contributes to a thickening in a part of the region that does not
matter
optically and technically for the entire combined system of the sealing disk,
even
when there is a folding back into the circular circumference, and that, on the
other
hand, a notching effect can no longer occur. The other disadvantages described
in
connection with the prior art also no longer occur.
According to the invention, the lowermost layer of the sealing disk following
on top of
the sealing layer and apart from the sealing layer itself, is formed in such a
way that
it projects outwardly over the edge, beyond the other layers of the sealing
disk. This
very thin layer is then bent upward first by 90 and guided past all other
layers that
belong to the group of lower layers that only close the container mouth part
prior to
the initial opening. Above the uppermost of these layers, the gripping tab is
then
folded again by 90 in the direction toward the center of the container and
applied flat
onto the uppermost of these layers. On top of this layer, which occupies only
a part
of the surface, is first found the separating layer, which separates the upper
group
and the lower group of layers from one another in the initial opening, and on
top of
this are found all layers of the upper group.
First of all, this has the consequence that prior to its use, in the operation
of filling the
container, the sealing disk has the form of a conventional, circular, flat
sealing disk
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CA 02758093 2011-10-06
and also can be treated as such. A particular alignment on the container is
not
necessary, since the sealing disk is outwardly symmetric.
The disk is also not essentially thicker than conventional disks, since only
the layer
placed between the other layers and later forming the gripping tab is added,
or
optionally another also very thin layer is added, which will be explained in
the
following preferred embodiments.
The container also need not be treated differently than it has been previously
for the
initial opening or for the later openings by the user. After screwing on the
screw cap,
the upper group of layers, which remain as the reseal parts of the screw cap
just as
they did previously, are separated by and at the separating layer, and the
lower
group of layers, which remain on the opening of the container, thus the
container
mouth part, seal and close this mouth part at this time, just as they did
previously.
Of course, unlike in the previous designs, a gripping tab is now applied
centrally on
the remaining part of the sealing disk, on top of the uppermost layer of the
lower
group, and is freely accessible to the user. The user need only take this
gripping tab
and pull it toward him, which needs no further explanation. By pulling, force
is
exercised on the edge of the lower group of sealing disks and, in fact,
directly on the
lowermost layer of this lower group of layers, this lowermost layer being
adjacent to
the sealing layer, since the gripping tab was made from this layer precisely,
prior to
the folding.
With this pull, the sealing layer immediately yields and the pull on the
gripping tab
thus simultaneously removes everything above this lower layer adjacent to the
sealing layer, therefore the complete lower group of the sealing disk with one
pull.
The container is thus opened.
Further procedures would then be possible just as in the case of conventional
re-
closing actions, due to the unchanged upper group of layers, thus due to the
reseal
part in the screw cap.
Based on this description, it is clear that a similar process is also
possible, not only
when the lowermost layer directly adjacent to the sealing layer is folded in
appropriate form and is formed for the gripping tab, but also when two or more
directly adjacent subsequent layers of the sealing disk can be folded.
sic; sealing layers?-Translator's note.
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It is particularly preferred in this case if a thin layer of a material that
is resistant to
tearing and is also simultaneously lightweight, is additionally inserted
between the
metallic layer providing for the induction and the melting sealing layer
providing for
the seal. This additional layer further preferably forms the gripping tab.
It is particularly preferred if this additionally inserted thin layer
comprises a tear-
resistant, but simultaneously lightweight material of polyethylene
terephthalate
(PET). Layers made of this material increase the tensile strength. This is
important
not only in connection with the gripping tab, but increases the tensile
strength of the
combined layer system containing the metallic layer that particularly
comprises
aluminum. The aluminum layer as such is not particularly resistant to tearing
for the
most part, so that combining it with such a thin tear-resistant PET layer is
also of
advantage in another respect.
This additionally inserted layer of polyethylene terephthalate would about a
notching
effect if it were arranged above the metallic layer. If this additional
plastic film with
the gripping tab formed thereon is then turned up and in, an inevitable
separation
movement is formed between this additional layer and the metallic layer lying
thereunder. This notching effect, however, will be avoided according to the
invention.
Above the metallic layer, the further layer sequence can be produced as
desired
each time for the particular case. In general, an adhered separating layer
will be
disposed here, which is strong enough to hold together the sealing disk in the
resting
state, but will yield so that the joining will be eliminated right at this
place when a
screwing process occurs.
On top of this separating layer, a support layer or foam layer is provided,
which
remains in the screw cap during the screwing process, and when it is closed
again,
provides for sealing for a certain amount of time.
The gripping tab made of the additionally inserted layer is now folded around
the
metallic layer in this embodiment, and is then folded first in the direction
of the axis of
the circular sealing disk. The adherent layer is thus found above this tab.
When the container is closed, the induction sealing process is not adversely
affected
by the additional layer. In fact, the metallic layer, which, for example and
preferably
comprises aluminum, is clearly heated by the induction and the eddy currents
produced thereby, and it delivers this heat also to this additional layer,
which is
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CA 02758093 2011-10-06
directly adjacent to it on the side facing the container. The stability of
this layer is not
adversely affected by this heat, however, and it delivers the heat flow
directly to the
subsequent sealing layer. The latter melts in turn, as intended, particularly
in the
edge region, and thus provides for the sealing to the edge of the mouth part
of the
container.
After cooling, the sealing layer now therefore seals the compound layer system
lying
over it opposite the container mouth part, thus at first opposite the
additional layer.
In the initial opening process, the consumer unscrews the screw cap and thus
detaches the connection through the separating layer. The upper parts of the
sealing
disk above this adherent layer remain in the screw cap.
This means that the consumer now directly looks at the tab, which lies bent
around
the metallic layer on top of this metallic layer, ready to grip.
Therefore, the consumer and user also immediately recognizes this gripping
tab: it
can be colored or also configured in another way so that it clearly stands out
optically
or in another form from the layers lying thereunder. In a particularly simple
manner,
the gripping tab can be colored in a striking signal color, e.g., in the
company color of
the producer of the container contents, and/or by printing the company logo or
trademark on the gripping tab.
The size of the gripping tab is less critical than in conventional designs,
since there is
no longer the danger that it will disrupt the function of the screw thread of
the screw
cap.
The gripping tab can thus project up to the center of the sealing disk or it
may also
possess complicated or ergonomically and haptically pleasing shapes.
It would even be conceivable to allow the gripping tab to assume a shape that
either
possesses a meaningful relationship to the product itself, thus, for example,
it may
have the stylized form of a coffee cup or of a piece of pastry, or in turn,
even the form
of a company logo.
If still further layers should be provided above the aluminum layer for a
special
application purpose, e.g., a layer used for printing or the like, the tab thus
also lies
above these layers and is also bent around these layers.
If the user now grips this tab, which is not adhered or otherwise fastened
onto the
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CA 02758093 2011-10-06
now uppermost layer adjacent to it, then the user can pull the tab [and
remove] all
the still present layers of the sealing disk from the mouth part of the
container by
exercising an appropriate manual force and thus can break open the seal.
Pulling the
tab pulls off all the layers above the additional layer at one time without an
additional
manipulation upward and there is no danger that not all of these layers will
be
removed by the pull on the tab, by gripping and pulling once.
The single layer that was found underneath the additional layer, adjacent to
the edge
of the container, was the sealing layer; this is precisely broken open,
however, by
this force without anything further, so that notching effects need not be
considered
here.
Further preferred features are indicated in the subclaims.
A production of this sealing disk according to the invention is possible,
preferably
with the method proposed in DE 10 2007 014 084 B3.
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An example of embodiment of the invention will be presented in more detail
below on
the basis of the drawing. Herein:
Figure 1 shows a perspective exploded view of a container with a mouth part
having
a sealing disk;
Figure 2 shows a top view onto a closed container having a sealing disk
according
to an embodiment of the invention after unscrewing the screw cap;
Figure 3 shows a section through a first embodiment of the invention;
Figure 4 shows a section through another embodiment of the invention with the
omission of several elements;
Figure 5 shows a section through a third embodiment of the invention with the
omission of several elements;
Figure 6 shows a section through a fourth embodiment of the invention with the
omission of several elements;
Figure 7 shows a section through a sheet of film for producing an embodiment
according to Figure 6; and
Figure 8 shows a section through a sheet of film for producing another
embodiment
according to Figure 6.
The mouth part of a container represented in Figure 1 shows the region of an
opening 11 of a container 10. This can be a bottle, a container for
agricultural
chemicals, a container to be closed in an aroma-tight manner, for example, for
powdered coffee, or a similar container. The opening 11 is surrounded by a
circumferential edge 12. The edge 12 is generally circular.
A sealing disk 20 that comprises several layers and that is closed at the top
and on
the side by a cover 15, in particular a screw cap with a screw cap base unit
is found
on this opening 11 after filling the container 10 but prior to opening it for
the first time.
The sealing disk 20 has approximately the same diameter as the opening 11 with
the
edge 12 of the container 10. The sealing disk 20 is sealed on the
circumferential
edge 12 by means of a sealing layer 31, which will be explained in more detail
below,
and which is not yet easily seen in the exploded representation in Figure 1.
The sealing disk 20 comprises two groups 30 and 40 of layers. The first group
30
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contains those layers of the sealing disk 20 that lie directly on the edge 12
of the
container 10 when the container has still not been opened, and upon a first
opening
of the container 10, in particular upon a first unscrewing or removal of the
cover 15
from the container 10, remain on the mouth part of the container, thus on the
opening 11. After the first unscrewing of cover 15, thus afterward just as
before, they
block the user's access to the content of the container 10.
The user removes this lower group 30 of layers of the sealing disk 20 from the
opening 11 after the initial opening of the container 10 and then gains
access.
Due to the circumstance that this lower group 30 of layers of the sealing disk
20 is
still found on the opening 11 of the container 10 when the container is first
opened,
the user can reliably conclude that no one before him has used this container
10 and
has removed content or has added unauthorized substances to the content of the
container 10. This lower group 30 therefore forms a type of authenticity seal.
In addition, a long-lasting sealing of the container contents against the
external
environment is also obtained by the seal, which safeguards, e.g., the aroma
found
inside the container, and reliably prevents the entry of oxygen, water vapor
or
microorganisms even over several years. The lower group 30 of the layers of
the
sealing disk 20 thus also has the task of preserving and protecting the
contents of
the container.
The upper group 40 of the layers of the sealing disk 20 is formed of those
layers that
remain in the cover 15 when the container 10 is first opened. These layers are
thus
removed together with the cover 15 during the first unscrewing and the user no
longer needs to remove them separately from the opening 11 of the container.
This
upper group 40 forms the so-called "reseal" part. After the user has obtained
access
to the content of the container 10 for the first time by removing the lower
group 30 of
layers of the sealing disk 20 and, for example, has removed part of the
contents
thereof, the user would usually like to store the remaining content of
container 10 in
order to again access it later. For this purpose, he screws cover 15 onto the
now free
opening 11 of container 10.
In fact, now that the lower group 30 of layers of the sealing disk 20 is
missing, the
upper group 40 of layers, thus the reseal part as mentioned, is now applied,
however, onto the edge 12 of the opening 11 of the container 10 and in turn
closes
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this opening.
No secure sealing occurs now in fact, although these upper layers of the group
40
are configured so that they can assure a sealing of the substance contents of
the
container 10 against the external environment over a long period of time,
although
this is not guaranteed, as was the case prior to the initial opening. Also,
protection
against unauthorized manipulation of the container content is no longer
provided, but
now the container is usually found in the possession and in the household of
an end
user, so that this function indicating an untouched condition is no longer
required.
In order to be able to separate the groups 30 and 40 from one another during
the
initial opening, the lowermost layer of the upper group 40 is formed as the
separation
layer 41. This separation layer 41 comprises a material, which in fact holds
together
the layers of the lower group 30 and of the upper group 40 of the sealing disk
20
during the manufacturing process and the closing of the container by the
packager or
bottler of the container 10 and usually further also holds these together
during the
entire manipulation of the container prior to the initial opening of the cover
15,
whereby the adhering effect is dimensioned sufficiently small, however, so
that the
upper group 40 can be lifted from the lower group 30 when an opening procedure
of
the cover 15 is performed.
Usually, a polymer separating layer, for example, of polyethylene or
polypropylene
film, or a wax-like material, will be used for this purpose.
Yet another layer 34 of the lower group 30 of layers of the sealing disk 20 is
also
indicated in Figure 1. A metallic layer 34 is involved here, which serves for
introducing induction heat, in order to melt the sealing layer 31 and thus to
guide a
secure seal onto the edge 12 of the opening 11 of the container 10 during the
filling
process of the container 10.
Further layers and details will be explained in the following.
First, however, now observe in Figure 2 a mouth part of a container 10, from
which
the cover 15 has just been unscrewed or otherwise removed. As a result of
this, the
upper group 40 of layers of the sealing disk 20 with the cover 15 is also no
longer to
be seen and one is looking at the lower group 30 of layers of the sealing disk
20,
which are still sealed, just as they were before, on the circumferential edge
12 of the
opening 11 of the container 10. The removal of this lower group 30 from the
edge 12
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thus has not yet occurred at the moment presented in Figure 2.
The observer thus obliquely views the uppermost layer 35 of the lower group 30
of
layers of the sealing disk 20. A gripping tab 50 lies flat on top on this
uppermost layer
35. This gripping tab 50 possesses a different coloring or another property by
means
of which it is clearly set apart from the uppermost layer 35 of the lower
group 30 and
immediately catches the eye of the user.
Gripping tabs 50 in conventional sealing disks projected outward over the edge
12 of
the opening 11 of the container 10 and were gripped there and then removed.
The gripping tab 50 in the embodiment according to the invention presented
here,
however, lies flat on top of the uppermost layer 35 of the lower group 30
lying
thereunder. It is not joined in its surface area with this layer lying
directly under it, but
is applied loosely. There is still a joining only at the edge of the sealing
disk 20,
which will be explained in more detail in the following.
The user can thus easily lift the gripping tab 50 at its flat part and grip it
and pull on it.
If the user pulls on the gripping tab 50, then he exercises force upward on
the edge
of the lower group 30 of the sealing disk 20, overcomes the sealing force of
the
sealing layer 31 on the edge 12 of the opening 11 of the container 10 and at
this site
pulls off the lower group 30 upward from the mouth part of the container.
The adhesion properties of the different layers, for example, of the sealing
layer 31,
are thus adjusted so that without great effort, the user can pull off the
entire lower
group 30 of the sealing disk 20 from the edge 12 of the opening 11 of the
container
with one pull on the gripping tab 50. The sealing force, however, is high
enough
that opening will still not result if only the cover 15 containing the upper
group 40 of
the layers of the sealing disk 20 is unscrewed, as described above.
Special attention must be paid, however, to the connection of the tab or
gripping tab
50 to the lower group 30 of the sealing disk 20. One should not bind this
gripping tab
50 to the uppermost layer 35 of the lower group 30 or form the uppermost layer
35
itself so that it projects over the circumference of the other layers of the
sealing disk
and projects out from the circumferential edge 12 of the opening 11 of the
container 10 and then simply fold the surface segment of the uppermost layer
35
projecting out over this edge 12 and fold it back on itself. This leads to
considerable
notching effects between this uppermost layer 35 and the layers of the lower
group
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CA 02758093 2011-10-06
30 lying thereunder. The uppermost layer 35 then has the tendency to detach
from
the other layers and thus the integrity of the entire sealing disk 20 becomes
questionable. This notching effect may occur in the manipulation of the
sealing disk
itself, prior to its introduction onto the container 10, but it will
especially occur later.
Several possibilities for a detailed construction will be explained in more
detail in the
following figures.
A section through a first embodiment of a sealing disk according to the
invention is
schematically shown in Figure 3. Container 10 is to be imagined on the bottom
and
cover 15 on the top; both of these have been omitted for clarity here. The
sealing
disk 20 is also shown partially pulled apart in order to be able to better
identify the
lower group 30 and the upper group 40.
Viewed from container 10, the disk 20 begins first with a sealing layer 31. A
layer 32
adjacent to the sealing layer 31 follows on top of this sealing layer 31. In
the
embodiment shown, this layer 32 is simultaneously a metallic layer 34. The
layer 32
adjacent to the sealing layer 31 is not necessarily the metallic layer 34, and
in most
of the embodiment examples it is not; the reference numbers refer to the same
layer
only in the embodiment of Figure 3.
This metallic layer 34 is simultaneously an induction layer, usually made of
aluminum. This induction layer or metallic layer 34 provides for transferring
heat
produced in layer 34 by means of induction to the sealing layer 31 and thus
solidly
sealing it on the edge 12 of the opening 11 of the container 10 in the process
of
producing or packaging the container 10.
In this embodiment, the uppermost layer 35 of the lower group 30 of layers of
the
sealing disk 20 follows next on top of the induction layer or metallic layer
34.
The upper group 40 made up of the upper layers of the sealing disk 20 begins
above
this uppermost layer 35. A separating layer 41 can be seen first. This
separating
layer separates the upper group 40 from the lower group 30 during the initial
opening. This layer involves a polymer separating layer, for example, a
polypropylene or polyethylene film or a wax-like substance. The layer 41
comprises
bonding agents and/or separating layers, for example, which bind the lower
layers 31
to 35 with the other layers lying above layer 35, but make possible a
separation
during the opening process.
CA 02758093 2011-10-06
A polymer separating layer is preferably used as a bonding agent for the layer
41. A
definitive adhesion, which can be predicted to be very good, can be obtained
with a
polymer separating layer. It should be considered that this layer must adhere
temporarily, but in the case of a rotating movement during an opening
procedure, it
must make possible a separation of the layers of lower group 30 lying
underneath
from the above-lying layers that will be explained further in the following.
A layer 42 is found above layer 41. Layer 42 is a polypropylene film or a
layer of
high-density polyethylene (HDPE). On top of this is found a foam layer 43. It
may
comprise polyethylene foam or polypropylene foam, or in some cases of
application,
it may also comprise cardboard. In certain frameworks, this springy, resilient
layer
provides for the tight closure of the opening 11 of the container 10 when
container 10
is re-closed after its initial opening.
Then another plastic film 44, e.g., of polypropylene or polyethylene (HDPE) is
provided as the uppermost layer. If the foam layer 43 comprises cardboard
material,
it is possible to omit layers 42 and 44, thus both plastic films of HDPE, in
particular.
This upper group 40 of the upper layers of the sealing disk 20 is also called
the
reseal part. In the originally closed container 10, the reseal part or this
upper group
40 lies directly on the layer 35.
All layers of the two groups 30 and 40 of the sealing disk 20 are joined
together very
solidly including the layers 32 to 35, since they are no longer separated and
need not
be separated from one another.
The total thickness of all layers of the lower group 30 is very small in
relation to the
other dimensions of the container and also the opening, usually being related
to the
thickness of the reseal part, thus the layers of the upper group 40.
It can be recognized further that the layers 31, 32 or 34 and 35,
respectively, not only
form a flat layer, but that at the edge of the sealing disk 20, these layers
are folded
back to the center of the sealing disk 20. It should be noted that the
thickness of the
layers and the dimensions as well as also the relative relationships are not
correct to
scale, but are presented purely schematically.
The uppermost layer 35, which would be a plastic film here, preferably of
polyethylene terephthalate, is folded back on itself in this case. The layers
lying
under it elsewhere in the layer sequence lie above it in this small folded
region. The
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CA 02758093 2011-10-06
uppermost layer of this folded region is thus a part of the sealing layer 31.
This region of the uppermost layer 35 [of this folded part or ripping tab] is
not flatly
adhered by its entire surface to the upper side of the uppermost layer 35 of
the lower
group 30, but lies loosely on it.
Since a thickening is therefore present on this side of the sealing disk 20,
the
separating layer 41 is adapted to it and leaves space here for the uptake of
this
additional material. Since the separating layer 41 is a polymer separating
layer or a
wax-like substance, this is possible without any problem.
An alternative to this is shown in Figure 4. A layer 33 made of a plastic film
is
additionally inserted between the metallic layer 34, which preferably
comprises
aluminum and serves as the induction layer, and the sealing layer 31. This
plastic
film preferably comprises polyethylene terephthalate.
Unlike in Figure 3, here this layer 33 is equally the layer 32 adjacent to the
sealing
layer 31, while the metallic layer 34 is equally the uppermost layer 35 of the
lower
group 30 of layers of the sealing disk 20.
The layer 33 of polyethylene terephthalate, which here forms the layer 32
following
the sealing layer 31, has an additional, positive effect. Whereas aluminum is
in
general not resistant to tearing, this resistance can be achieved in a very
practical
manner with a plastic film, in particular, of polyethylene terephthalate
(PET). The
combined system of the lower layers with the aluminum layer 34 and the
additional
layer 32 is thus resistant to tearing overall, which is very advantageous for
this unit of
the lower group 30 of layers.
The upper group 40 is omitted here, since it corresponds exactly to the design
of the
embodiment of Figure 3.
On the right side, it can be seen that in this case, the sequence of the
folded layers is
different than in the representation of Figure 3. The gripping tab 50 here has
the
layers: sealing layer 31, plastic film 33 and metallic layer 34 in this
sequence from
top to bottom, these layers lying on the upper side of the uppermost layer 35.
The representation of Figure 4 is rendered slightly modified in Figure 5.
Since the
sealing layer 31 is provided for sealing onto the edge 12 of the opening 11 of
the
container 10, it is relatively sticky, which in some circumstances is not
desired in the
17
CA 02758093 2011-10-06
region for the gripping tab. This could be disruptive both in the handling by
the user
as well as in the defined separating effect of the directly adjacent
separating layer 41
of the two groups 30 and 40.
For this case, in an embodiment of this type, or also in other embodiments,
correspondingly, the side of the sealing layer 31 directed upward may be
provided
with an additional protective coating 38 or a protective film 38.
The sealing layer 31 is not necessary or desired in the region of the gripping
tab 50,
since it contributes little or nothing at all to the tensile strength of the
material. Of
course, it frequently will be simpler in terms of manufacturing technology to
fold the
sequence of layers of the lower group 30 as a whole and not to omit specified
regions. It should be noted that the sealing disks are punched out of large
sheets
and that in this case, small areas around the region of a sealing disk can be
executed in complicated form under certain circumstances. It can therefore be
simple
to additionally apply a protective coating here or to cover this region of the
sealing
layer 31 above the gripping tab 50 in another way during the production of the
sealing disk.
A variant is shown in Figure 6, in which the sealing layer 31 is actually
omitted on
the folded upper side of the lower group 30 that forms the gripping tab 50.
Likewise, in this embodiment, it is also provided to allow the metallic layer
34 to end
at the edge of the sealing disk, and therefore not to fold it back and not
allow it to run
out into the gripping tab 50.
This embodiment thus has a great advantage in that the induction that is
introduced
into the sealing disk is more uniform. In the embodiments of Figures 3, 4 and
5, it
can be recognized that an overall thicker metallic region is formed, which
could
correspondingly also need to take up more heat, which should be compensated
for
correspondingly in the induction sealing. This is avoided from the outset in
the
embodiment of Figure 6.
In this embodiment also, a notching effect cannot occur between the plastic
film 33
provided with the gripping tab 50 (simultaneously, the layer 32 adjacent to
the
sealing layer 31) and the other layers, thus here the metallic layer 34. The
tab 50
surrounds the outer edge of the metallic layer 34 and the notching effect can
only
occur between the plastic film 33 and the sealing layer 31, where it is
specifically
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CA 02758093 2011-10-06
desired.
The representation in Figure 6 specifically shows a particularly preferred
embodiment.
Also, in the representation of Figure 6, care is taken that the gripping tab
50 which is
formed particularly thin here is not solidly adhered onto the upper side of
the
uppermost layer 35 of the lower group 30 of layers of the sealing disk 20.
It is shown in Figure 7 how a sheet of film roughly in cross section could
appear,
from which sealing disks are folded and punched out for an embodiment
according to
Figure 6.
Figure 8 shows a modified variant of the embodiment of Figure 6, in which, in
fact,
the sealing layer 31 runs out into the gripping tab 50, but not the metallic
layer 34.
When container 10 is opened for the first time by unscrewing the cover 15 with
the
screw cap, the connection in the separating layer 41 between the layers 35 and
42 is
broken. This can be produced in different ways. It is appropriate to keep the
upper
group 40 freely rotatable in the closure, thus in the screw cap 15, but, e.g.,
to hold it
by projections or lifting pieces, so that when the screw cap 15 is rotated,
the layers of
the group 40 are pulled vertically upward and thus are separated from the
layers of
group 30.
Another, less preferred, but basically possible form consists in first
carrying out a
connecting of the reseal part, thus group 40, to the underside of the screw
cap 15, so
that when screw cap 15 is rotated, there occurs also a rotating motion of the
layers of
group 40 relative to the layers of group 30, which leads to the separation.
After the first opening of the screw cap 15 in both cases, i.e., in the
embodiment of
Figure 8, in which the layers of the group 40 are pulled vertically upward as
well as
also in the basically possible form, in which a rotating motion separates the
layers,
the uppermost layer 35 of the lower group 30 lies in front of the user. The
user then
grips the gripping tab 50 and thus pulls all layers of the group 30 in one
pull from the
edge 12 of the opening 11 of the container 10.
In all embodiments of Figure 8, the occurrence of notching effects between the
layer
with the gripping tab 50 and other layers is thus also completely avoided;
only a
separation of the lower group 30 from the sealing layer 31 or a separation
within the
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CA 02758093 2011-10-06
sealing layer 31 occurs. The group 30 of lower layers thus remains intact and
is
pulled off as a whole without leaving behind residues on part of the surface
of
opening 11 of the container or also without surface separations due to the
notching
effect being able to occur.
A repeated screwing on of the cap 50* leads to the circumstance that the layer
42 of
the reseal part comes to lie on the edge 12 of the opening 11 of the container
10 and
seals it again.
In those embodiments in which an additional, conventionally absent layer 33
made of
a plastic film is inserted between the metallic layer 34 and the sealing layer
31, this
layer 33 then forming the layer next to layer 32, an additional layer now lies
between
the layer mediating induction heat and the sealing layer itself. However, this
is
comparatively easy to take into consideration, since only a small distance,
which is
slightly enlarged by the thickness of a thin plastic film, is present between
the
metallic layer and the sealing layer 31 to be heated. Slightly more induction
heat will
be required. The difference is minimal, of course, since it involves only a
few
pathways for losing the heat generated.
sic; cap 15?-Translator's note.
CA 02758093 2011-10-06
List of reference characters
Container
11 Opening of the container
12 Circumferential edge of the opening
Cover, in particular screw cap
Sealing disk
Group of lower layers of the sealing disk
31 Sealing layer
32 Layer adjacent to the sealing layer
33 Layer of plastic film, in particular polyethylene terephthalate
34 Metallic layer, in particular aluminum
Uppermost layer of the lower group
38 Protective coating or protective film
Group of upper layers
41 Separating layer
42 Plastic film, e.g., polypropylene or polyethylene
43 Foam layer
44 Plastic film, e.g., polypropylene or polyethylene
Gripping tab
21
