U.S. patent application number 13/581375 was filed with the patent office on 2012-12-20 for container with closing membrane.
This patent application is currently assigned to AMCOR FLEXIBLES KREUZLINGEN LTD.. Invention is credited to Detlef Wolters.
Application Number | 20120318801 13/581375 |
Document ID | / |
Family ID | 42288627 |
Filed Date | 2012-12-20 |
United States Patent
Application |
20120318801 |
Kind Code |
A1 |
Wolters; Detlef |
December 20, 2012 |
CONTAINER WITH CLOSING MEMBRANE
Abstract
In a container with an externally protruding annular flange
which delimits an opening and is delimited by a beaker edge, and
with a film-like closing membrane which, forming a common annular
connecting surface delimited by an inner ring edge and an outer
ring edge, is sealed against the flange to close the opening, and
which can be peeled off the flange and is delimited by a membrane
edge with a tear-off tab protruding beyond the beaker edge, the
closing membrane, starting from the tear-off tab protrudes freely
beyond the outer ring edge of the connecting surface and the
distance of the membrane edge to the outer ring edge starting from
the tear-off tab, on both sides of the tear-off tab up to an angle
of at least 45.degree. in relation to a diameter line running in a
tear-off direction (x), diminishes constantly to zero.
Inventors: |
Wolters; Detlef; (Muellheim,
DE) |
Assignee: |
AMCOR FLEXIBLES KREUZLINGEN
LTD.
Kreuzlingen
CH
|
Family ID: |
42288627 |
Appl. No.: |
13/581375 |
Filed: |
March 1, 2011 |
PCT Filed: |
March 1, 2011 |
PCT NO: |
PCT/EP2011/000985 |
371 Date: |
August 27, 2012 |
Current U.S.
Class: |
220/359.2 |
Current CPC
Class: |
B65D 77/204 20130101;
B65D 77/2032 20130101 |
Class at
Publication: |
220/359.2 |
International
Class: |
B65D 17/34 20060101
B65D017/34 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 10, 2010 |
EP |
10405050.5 |
Claims
1. A container with an externally protruding annular flange which
delimits an opening and is delimited by a beaker edge, and with a
film-like closing membrane which, forming a common annular
connecting surface delimited by an inner ring edge and an outer
ring edge, is sealed against the flange to close the opening, and
which can be peeled off the flange and is delimited by a membrane
edge, with a tear-off tab protruding beyond the beaker edge,
wherein the closing membrane, starting from the tear-off tab
protrudes freely beyond the outer ring edge of the connecting
surface and the distance of the membrane edge to the outer ring
edge starting from the tear-off tab, diminishes constantly to zero
on both sides of the tear-off tab up to an angle of at least
45.degree. but maximum up to an angle of 90.degree. in relation to
a diameter line running in a tear-off direction (x).
2. A container according to claim 1, wherein the common annular
connecting surface is arranged concentric to the beaker edge and
the outer ring edge of the connecting surface substantially
coincides with the beaker edge.
3. A container according to claim 2, wherein the beaker edge is
formed eccentrically and substantially coincides with the closing
membrane.
4. A container according to claim 1, wherein the common annular
connecting surface on the diameter line running starting from the
tear-off tab in the tear-off direction (x) is arranged
eccentrically to the annular flange by a shift dimension (a)
directed away from the tear-off tab and the edge of the closing
membrane, apart from the tear-off tab, substantially coincides with
the beaker edge.
5. A container according to claim 4, wherein instead of an
eccentric shift of the annular connecting surface, the beaker edge
is formed eccentric.
6. A container according to claim 1, wherein the common annular
connecting surface, to reduce the tear resistance, is designed
reduced or narrower in the region of the tear-off tab.
Description
[0001] The invention concerns a container with an externally
protruding, annular flange which delimits an opening and is
delimited by a beaker edge, and with a film-like closing membrane
which, forming a common annular connecting surface delimited by an
inner ring edge and an outer ring edge, is sealed against the
flange to close the opening, and which can be peeled off the flange
and is delimited by a membrane edge, with a tear-off tab protruding
beyond the beaker edge.
[0002] It is known to provide containers, such as for example
deep-drawn, injection-moulded or otherwise formed containers, at
their opening with a flat annular flange and to close such
containers with a lid, in particular after filling, wherein the lid
or closing membrane lies across the full surface of the flange and
for example is attached tightly sealing and peelable by sealing or
gluing to the flange. Such containers, dishes, menu trays for
example with one or more compartments, beakers, small packings etc.
are known for example for packing foodstuffs of all types, e.g.
dairy products, in particular yoghurt, whipping cream, sour cream,
coffee cream, finished preparations of salads or semi- or full
preserves, precooked or otherwise prepared meals, drinks such as
fruit and vegetable juice or drinking water.
[0003] The lids, boards or closing membranes are for example
punched out of an endless film-like lid material and stacked. The
lid stacks are supplied to a packaging machine and the separated or
unstacked lids with a sealing layer are continuously sealed by
means of a sealing tool onto the container edge of the previously
filled containers in the flange region of the container. The lids
are often embossed or fitted with spacers when processed from
magazines. Alternatively, the lid film can also be processed from a
roll and punched out together after sealing with the beaker.
[0004] Normally the lid material is sealed flush to the beaker edge
and the lid is typically raised at a tear-off tab. By pulling the
tear-off tab, the lid is detached from the seal flange by peeling
without tearing and thus preventing a complete opening of the
container. However opening the lid leads to a particularly
unfavourable pull angle in which the film is easily torn. Here the
tensile force on opening the lid acts particularly strongly on the
lid edge so that the lid no longer peels from the beaker but tears.
The tendency to tear is particularly high at the start of the
tear-off process as the lid edge here requires particularly little
force to tear. As opening progresses, the risk of tearing
increasingly diminishes.
[0005] The tearing of the lids or closing membranes on opening
constitutes an irritation to the consumer. Tearing also prevents
further thinning of the lid material as this would cause even more
tearing due to the lower tear force required.
[0006] A relatively firm seal e.g. above 8 Nm/15 mm and the typical
flush sealing of the lid film with the outer beaker edge contribute
particularly greatly to tearing, as the lid film is virtually torn
away from the seal edge. Here the relatively low tear or tear
progression resistance of the lid materials, in contrast to the
high tensile strength of the lid material, acts directly on the
edge of the lid.
[0007] The tearing of the lid material can be prevented by
increasing the material thickness or by lamination with
tear-resistant films. Both solutions substantially increase the
costs.
[0008] WO 2008/0116444 A1 discloses, to prevent tearing in peelable
lids sealed to a container edge, reinforcing the lid edge e.g. by
folding at least in the critical region.
[0009] For lid rings for crimping onto cans, WO 2008/068326 A1
discloses in one embodiment that the sealing film which is sealed
to the lid ring to prevent tearing of the film edge during the
pull-off process has an edge strip extending over the entire edge
of the film and protruding beyond its fixing region. In another
embodiment the closing film has "ears" protruding externally beyond
the fixing region on both sides of the grip tab.
[0010] The solutions offered in the prior art are associated with
an additional material usage and hence higher costs.
[0011] The invention is based on the object of designing, in a
container of the type cited initially, the connection of closing
membrane with the container such that with only slightly greater
material use, opening is possible without tearing the membrane.
[0012] The solution to this task according to the invention is that
the closing membrane, starting from the tear-off tab, protrudes
freely beyond the outer ring edge of the connecting surface and the
distance of the membrane edge to the outer ring edge, starting from
the tear-off tab, diminishes constantly to zero on both sides of
the tear-off tab up to an angle of at least 45.degree. in relation
to a diameter line running in a tear-off direction.
[0013] Preferably, the distance of the membrane edge to the outer
ring edge of the connecting surface diminishes constantly to zero
up to an angle of around 90.degree..
[0014] The solution according to the invention overcomes the
possibility of tearing with a low tearing resistance. The gradual
transition of the tear-off tab allows the necessary resistance of
the closing membrane over the sealing edge to be kept very low and
leads to an additional material consumption of only around 1%.
[0015] The tear resistance can also be reduced in that the
connecting surface between the flange and closing membrane is
reduced in the region of the tear-off tab, e.g. by a narrower
design. In practice this can be achieved for example by a
corresponding step in the flange.
[0016] On sealing beaker materials, depending on sealing medium and
conditions, very high tear-off forces can occur. The tear-off force
differs greatly over the periphery of the beaker and is
characterised in particular by a strong rise at the start of the
opening process and on tearing the membrane away when the container
is opened. This second rise in tensile force can be ignored as
usually the membrane is left on the container at the rear end of
the periphery by the consumer.
[0017] The first very strong tension rise is achieved in the moment
where the unsealed edge region of the tear-off tab of the lid
reaches the so-called collision point on the sealed container edge.
With very strong seals, with a flush seal all round of the membrane
with the beaker edge, it is even often observed that the tab is
separated from the remainder of the lid.
[0018] Surprisingly, it has now been shown that by avoiding a
run-up of the tab edge at the beaker edge, said tension peak can be
substantially reduced. Thus the beaker can be opened with less
force and much more evenly. After half opening, the avoidance of
the collision point between lid edge and beaker edge is not
required as the rear lid periphery does not run towards the beaker
edge but due to the modified pull direction, is merely peeled away
from this.
[0019] In a first embodiment, the common annular connecting surface
is arranged concentric to the beaker edge and the outer ring edge
of the connecting surface substantially coincides with the beaker
edge.
[0020] In this embodiment, starting from and to both sides of the
tear-off tab, there is a protrusion of the closing membrane over
the beaker edge in the region of a first flange half. This
protrusion can if necessary be avoided by a flange or beaker edge
formed eccentric in this region.
[0021] In a second embodiment, the common annular connecting
surface is arranged on the diameter line running starting from the
tear-off tab in the tear-off direction, eccentrically to the
annular flange by a shift dimension directed away from the tear-off
tab, and the edge of the closing membrane apart from the tear-off
tab substantially coincides with the beaker edge.
[0022] Instead of an eccentric shift of the annular connecting
surface to the flange, in this embodiment the flange or beaker edge
can be formed eccentric.
[0023] Depending on the requirements imposed, the lid material can
comprise various materials. Typical examples are metal foils coated
with plastic on one or both sides. Other lid materials contain or
consist of plastics in the form of monofilms or multilayer
laminates. Further lid materials can consist of
cellulose-containing materials such as cellular glass or paper.
Laminates of metal and plastic films can also be used. To seal the
lid material to the container edge, the lid material is usually
coated over the full surface with a sealing layer such as a sealing
lacquer, a sealable extrusion layer or a sealing film, wherein the
sealing layer is arranged on the side facing the inside on the
finished packaging, i.e. facing towards the container interior. In
non-metallic films or metal films protected completely against
corrosion, however, annular or partially applied sealing layers are
also possible.
[0024] The containers are usually formed from plastic by
deep-drawing or injection-moulding. Suitable containers can also be
made by deep-drawing of lacquered or extrusion-coated films of
metal or of metal/plastic laminates.
[0025] Further advantages, features and details of the invention
arise from the description below of preferred embodiment examples
and with reference to the drawing which depicts schematically
in
[0026] FIG. 1 a section through a container with flange and closing
membrane sealed against the flange;
[0027] FIG. 2 a view onto the rear of the flange of the container
in FIG. 1 in view direction Y, with a closing membrane sealed
against the flange in a first manner;
[0028] FIG. 3 a view onto the rear of the flange of the container
in FIG. 1 in view direction Y, with a closing membrane sealed
against the flange in a second manner.
[0029] A container 10 shown in FIG. 1 in the form of a beaker of
plastic to receive yoghurt, for example, has a base 12 and
protruding from this a side wall 14 delimiting a filling product
volume. The side wall 14 extends upward from the base 12, in the
example shown with an outwardly directed angle of incline, and at
its end remote from the base transforms into a horizontally
outwardly projecting annular flange 16. The transition of the side
wall 14 into the annular flange 16 delimits a container opening 18.
The free end of the flange 16 forms a container edge 20. Sealed to
the annular flange 16 is a film-like board or closing membrane 22
which is peelable from the flange 16 and tightly seals the
container opening 18. The seal is achieved with a sealing tool with
an annular or full-surface die and leads to a common annular
connecting surface 28 delimited by an inner ring edge 24 and an
outer ring edge 26 between flange 16 and closing membrane 22. The
closing membrane 22 which is delimited by a membrane edge 21 at one
point has a tear-off tab 23 protruding from the container edge
20.
[0030] In a first type of connection between flange 16 and closing
membrane 22 shown in FIG. 2, the seal is achieved such that the
common annular connecting surface 28 between flange 16 and closing
membrane 22 is arranged concentric to the flange 16, and the outer
edge 26 of the annular connecting surface 28 substantially
coincides with the beaker edge 20. Starting from the tear-off tab
23, the closing membrane protrudes beyond the outer ring edge 26 of
the annular connecting surface 28 and hence also beyond the beaker
edge 20, wherein the distance between the edge 21 of the closing
membrane 22 and the beaker edge 20 diminishes constantly to zero on
both sides of the tear-off tab 23, over a first flange half up to
an angle of 90.degree. on both sides to a diameter line defining a
tear-off direction x. Over the next second flange half, the
membrane edge 21 runs coincident with the beaker edge 20 or the
outer ring edge 26 of the annular connecting surface 28. To
guarantee peeling of the closing membrane 22 without risk of
tearing, the membrane edge 21 should protrude beyond the beaker
edge 20 up to at least an angle of around 45.degree. on both
sides.
[0031] In a second type of connection between flange 16 and closing
membrane 22 shown in FIG. 3, the seal is achieved so that the
common annular connecting surface 28 between flange 16 and closing
membrane 22 is arranged eccentrically to the annular flange 16 on
the diameter line running from the tear-off tab 23 in the tear-off
direction x, by a shift dimension a directed away from the tear-off
tab 23, and the edge 21 of the closing membrane 22, apart from the
tear-off tab 23, substantially coincides with the beaker edge 20.
On both sides of the tear-off tab 23, the closing membrane 22 which
is coincident with the beaker edge 20 protrudes beyond the outer
ring edge 26 of the annular connecting surface 28, wherein the
distance between the edge 21 of the closing membrane 22 and the
outer ring edge 26 of the annular connecting surface 28 diminishes
constantly to zero on both sides of the tear-off tab 23, over the
first flange half up to an angle of 90.degree. on both sides to the
diameter line defining the tear-off direction x. Over the next
second flange half, the membrane edge 21 runs substantially
coincident with the beaker edge 20 or the outer ring edge 26 of the
annular connecting surface 28. To guarantee peeling of the closing
membrane 22 without risk of tearing, the membrane edge 21 in this
variant too should protrude beyond the outer ring edge 26 of the
annular connecting surface 28 up to at least an angle of around
45.degree. on both sides.
[0032] The closing membranes shown in the drawing have a circular
round form corresponding to beakers with a circular round opening.
The invention is not however restricted to these examples but
comprises also other geometric container openings and lid shapes
such as e.g. oval and polygonal shapes.
* * * * *