EP1181217B1 - Sealing disc and film composite for a closure of a container - Google Patents

Abstract

A sealing disc and a film composite for a container closure is provided, for use on a container with an opening bounded by a peripheral edge. The film composite includes a plurality of layers. An adhesive layer is arranged at least over a joining surface between the upper layer and the underlying layer.

Description

The invention relates to a sealing washer and a film composite for a container closure for use in a container with an opening delimited by a peripheral edge, the film composite consisting of several layers and an adhesive layer being arranged between the upper layer and the layer below it at least over a partial surface.

When closing a container, it is often desirable or also necessary to provide the container mouth with a disk-shaped seal that seals the contents, for example liquids or substances such as food, tightly.

There are several reasons why this tight closure is required. On the one hand, the content should be protected against external influences, for example against water vapor or oxygen, and on the other hand it should also remain aroma-tight. Another reason lies in aggressive filling goods, for which the best possible leakage protection must be provided. Finally, such a tight seal can also provide a tamper-evident protection for the trade, since a user can immediately recognize whether someone has already manipulated the container contents beforehand.

In addition, the container closure is then closed with a screw cap or a similar element, which ensures the mechanical and stable closure outside the film. When used for the first time, the user destroys the film in order to access the contents of the container and then closes the container (if he has not yet removed all of the contents) with the screw cap, which can temporarily seal the opened contents for a correspondingly short period of time.

The film that closes the contents of the container is often applied using induction sealing. To do this, a complete sealing washer is placed, the bottom layer of which forms the sealing layer. There is a As a rule, aluminum consists of a second layer, which serves to generate and transfer heat during the induction process and, if necessary, forms additional mechanical protection. The second layer is fixed to the first and is particularly advantageous for heat transfer. Above this aluminum layer, further components of the sealing washer are then provided, which remain in the cap when the screw or other twist lock is opened.

The removal of the film can be troublesome for the user. For this he needs a tool, for example a knife or scissors, which leads to the risk that parts of the film fall into the container contents. In addition, suitable tools are not always available. There are also screw closures, the outside of which is designed in such a way that, when used in reverse, they allow the film to be cut or torn. This makes the screw cap more expensive and it is also necessary to provide the user with appropriate instructions so that he can make the opening appropriately.

As an alternative, it has already been proposed, for example, in EP 0 697 345 A2 to provide the sealing washer or at least the film composite on its edge with corresponding projections or grip tabs that the user can grip so that the sealed film can then be easily removed , However, this very sensible construction cannot be used in every case, since these projecting tabs must be able to be arranged between the screw thread and the outside of the container opening after the screw cap has been put on, which can lead to geometric difficulties. It is also problematic if, for example, the upper parts of the sealing washer are not allowed to have noses because this prevents them from remaining in the screw cap part. Two different punching processes would then have to be provided for the film composite and the upper parts of the sealing washer, which leads to additional costs.

It has therefore been proposed in EP 0 395 660 B1 and EP 0 534 949 B1 to build up the sealed film composite from two layers, the about half of the surface is glued to one another, while the other half remains free. As a result, that half of the upper layer that is not glued can be easily lifted off, while the other surface remains connected during this lifting off. If such a two-layer, partially glued film composite is used on the container, the user only has to grip this half of the upper layer, which lies flat but can be easily lifted off, and can then pull off the entire film composite by applying appropriate force.

This rather obvious concept has some disadvantages. It is, of course, a mass product in which cost considerations play a very important role. A method must therefore be found in which two layers can be connected to one another in such a way that they are only partially bonded. This can be done by a relatively complex lamination.

Another disadvantage is that the partially open upper layer causes problems when filling and closing the containers. If the screw cap is attached in a rotating manner, it tends to attack the film by friction. Since the upper layer is partially loose, it is occasionally pulled slightly here, which can immediately lead to uncontrolled wrinkles and also to kinking and destruction. In the container filling industry, even minimal reject rates are highly undesirable, since the entire container usually has to be discarded or can lead to complaints.

The object of the invention is therefore to propose a sealing washer and a sealing film for a container closure, which also leads to an easy opening of the film for the user, but at the same time is inexpensive and reliable in production and does not require any additional punching processes.

This object is achieved in a film composite in that the uppermost of the layers of the film composite has an upwardly projecting fold.

For example, a film composite is known in US Pat. No. 4,934,544, with all layers of the film composite having an upwardly projecting fold.

With a fold of this type, all advantages can be used which concepts from EP 0 395 660 B1 or EP 0 534 949 B1 also have. It is not necessary to cut open the film composite or to provide tabs protruding over the edge. Of course, the fold lies flat on the top of the remaining film composite when the screw cap is attached. However, it is not glued to it, since here the outside of the upper layer lies on another area of the outside of the upper layer.

The user simply grabs this fold, sets it up and then pulls off the entire film composite with it. As a rule, he will take one end of the fold and at this point he will be able to pull the film vertically slightly upwards, which will result in the remaining edge "rolling".

On the other hand, the disadvantages from the aforementioned prior art advantageously do not exist. The outer edge of the film composite is identical all around from the same structure: both the upper and the lower layer are present everywhere. There is therefore no tendency to crease or wrinkle.

In contrast to the prior art, the flattened fold represents additional material and is therefore relatively insensitive. Without an additional punching process, it does not protrude all the way to the edge, even in the flat state, but ends beforehand.

The fold is particularly preferably arranged so that it is off-center. As a result, it will tend to fold in one direction without adversely affecting the placement in any form.

However, in order to facilitate the grip area and the tearing open, the fold should remain relatively adjacent to the center, so that a division of the total surface is preferred so that the smaller area takes up an area of 40 to less than 50% of the total area.

It has proven to be particularly practical to grasp if the fold has a distance between 0.5 and 2 cm, in particular between 1 and 1.5 cm, between the fold foot directly on the sealing film and the fold tip.

It is also preferred if the adhesive layer is in any case provided in the region of the upper layer which forms the fold. As a result, contact is made in this area from adhesive layer to adhesive layer within the fold, which enormously increases and improves their stability and firm adherence, which has a corresponding effect on the tear and tensile strength and also prevents the fold from bulging or possibly due to external influences rises oval.

Ultimately, it is particularly preferred if the adhesive layer occupies the entire area of the upper layer. This is advantageous from a manufacturing point of view; the strip lamination known from the prior art with partial provision of an adhesive layer and partial omission is expensive and the full-surface gluing also improves the stability and the adhesion of the entire film composite.

It is further preferred if the total area of the sealing film is slightly larger than the opening to be covered, including the peripheral edge.

This very slightly protruding amount of material makes it easier to pull off the edge when gripping the fold. This creates a very small edge area which should not be touched at all, but which is without any direct adhesion to the peripheral edge of the opening of the container when the fold is pulled up and thus has a favorable influence on the marking process. On the other hand, this protruding edge is dimensioned so small that it is significantly smaller than, for example, the tabs from EP 0 697 345 A2 and in no case comes into engagement with the screw cap.

In the case of a sealing washer, the object is achieved in that the lower layers of the sealing washer have the film composite according to one of the above combinations of features.

Such a sealing washer has all the advantages mentioned. It is easily possible to include the layer forming the fold together with this fold in the production of the sealing washer and then to use the complete compound in the packaging industry.

Figur 1

eine schematische Perspektivansicht eines Behälters mit einer ersten Ausführungsform der Versiegelungsfolie;

Figur 2

ein schematischer Schnitt durch die Versiegelungsfolie aus Figur 1; und

Figur 3

ein schematischer Schnitt durch eine Dichtscheibe mit einer Versiegelungsfolie entsprechender Ausführungsform aus Figur 2.

An exemplary embodiment of the invention is described in detail below with reference to the drawing. Show it:

Figure 1

is a schematic perspective view of a container with a first embodiment of the sealing film;

Figure 2

a schematic section through the sealing film of Figure 1; and

Figure 3

3 shows a schematic section through a sealing washer with a sealing film of the corresponding embodiment from FIG. 2.

A container 10 is filled, for example, with food or agrochemicals or other oxygen-sensitive goods, in particular with liquid. It has an opening 11 from which the content is to be removed in due course. The opening 11 is surrounded by a peripheral edge 12.

The opening 11 is closed by a film composite 30. Above the film composite 30 there is still a screw cap, not shown, with which the container can be at least provisionally closed even when the film composite 30 is destroyed. The screw cap also serves to protect the film composite 30 against mechanical influence from the outside.

The film composite 30 has in particular three film and two adhesive layers. This can be clearly seen in FIG. 2. The bottom layer 34 is fixed in the sealed state exactly on the peripheral edge 12 of the container 10. An adhesive layer 35 is arranged on the first or lowest layer 34, which firmly connects this first layer 34 to a second layer 31. The second layer 31 is an induction foil, in particular made of aluminum. If it is heated by induction, this heat is transferred to the lowermost layer 34 and thus seals it on the edge 12.

A further adhesive layer 32 is provided on this second layer 31, the induction film. The second adhesive layer 32 connects this layer 31 to the uppermost layer 33 throughout.

The layer 33 has a fold 40. The layer 33 is flat outside the area of the fold 40 and is continuously connected to the layer 31 underneath via the adhesive layer 32. In the area of the fold 40, starting from the fold foot 41, the entire layer 33 is laid twice and thus projects up to the fold tip 42 and from there back to the fold foot 41. Between these two double layers of material in the upper layer 33 there is also the adhesive layer 32, preferably also twice. This can be done during production by coating the top layer 33 over the entire surface with the adhesive layer 32 in the still unfolded state and then folding it onto the layer 31 of the induction film during the web production, with the addition of this fold. The fold 40 is particularly stable and, due to the double adhesive, also particularly firmly connected. Nevertheless, it can appear light and filigree, for example in that the entire layer 33 is made of a transparent material.

The fold 40 extends perpendicular to the image plane across the film. The distance between pleat foot 41 and pleat tip 42 is constant, possibly with bevels or curves in the edge area. The fold tip thus forms an essentially straight line.

In Figure 1 it can be seen how this affects overall. The entire container mouth or opening 11 of the container 10, which is covered by the film composite 30, is at the same time provided just eccentrically with the fold 40 which rises upwards from the fold foot 41 lying exactly in the plane of the opening 11 of the container 10. The fold 40 is shown slightly oblique, which is due to the fact that it lies completely flat in the packaged state, thus taking up little space and also offering no reason to be gripped by the screw cap when screwing on.

FIG. 3 schematically shows a complete sealing disc 20, of which the film composite 30 with its three film and two adhesive layers 31, 32, 33, 34 and 35 together with fold 40 offers the lowest part.

The upper part can be a polyamide layer or another polymer.

It can be used for all containers, glass, PET, PAC, PP; PVC. The sealing layer below the aluminum induction film layer 31 is adapted to the respective material of the container.

For the end user there is an excellent quality, a construction that is easy to open by means of the projecting fold, which also opens reliably and does not tear off.

For the bottler or packaging manufacturer, there is the advantage that such a sealing film or sealing washer can be used particularly reliably without problems having to be expected during the filling process.

For the manufacturer of the sealing film, there is the advantage that he no longer has to undertake strip lamination, but only has full-surface materials in front of him.

The fold 40 is not formed until the punching process. A corresponding apparatus of a punch measuring apparatus turns out that the full-surface material runs in folded accordingly.

LIST OF REFERENCE NUMBERS

10

container

11

opening

12

Edge of the opening

20

sealing washer

30

film composite

31

second layer, induction foil layer

32

second adhesive layer

33

top layer

34

bottom layer, sealing layer

35

first adhesive layer

40

wrinkle

41

creaser

42

fold peak

Claims (12)

1. Film composite for a container closure for use on a container (10) with an opening (11) bounded by a peripheral edge, wherein the film composite (30) consists of a plurality of layers and between the upper-most layer (33) and the layer (31) beneath it there is arranged an adhesive layer (32) at least over part of a surface,
   characterised in that
   only the upper-most layer (33) of the film composite (30) comprises an upwardly projecting fold (40).
2. Film composite according to claim 1,
   characterised in that
   the film composite (30) consists of at least three layers (31, 33, 34), of which the bottom-most layer (34) is a sealing layer, the middle layer (31) is a layer producing the induction heat and the upper-most layer (33) is the layer facing the user.
3. Film composite according to claim 1 or 2,
   characterised in that
   the fold (40) is arranged off-centre.
4. Film composite according to claim 3,
   characterised in that
   the fold (40) is so arranged that it divides the surface of the opening (11) of the container (10) into two areas, the smaller of which makes up between 40 and less than 50% of the surface.
5. Film composite according to one of the preceding claims,
   characterised in that
   the fold (40) possesses a fold bottom (41) which forms a straight line that passes diagonally through the entire area of the film composite zone arranged on the opening (41).
6. Film composite according to one of the preceding claims,
   characterised in that
   the fold (40) possesses over its entire length a constant height from the fold bottom (44) to the fold tip (42).
7. Film composite according to one of the preceding claims,
   characterised in that
   the fold (40) extends roughly 0.5 to 2 cm from the fold bottom (41) to the fold tip (42).
8. Film composite according to claim 7,
   characterised in that
   the fold (40) extends roughly 1 to 1.5 cm from the fold bottom (41) to the fold tip (42).
9. Film composite according to one of the preceding claims,
   characterised in that
   the upper layer (33) forming the fold (40) is provided with the adhesive layer (32) in such a way that the adhesive layer (32) also covers the surface area forming the fold (40).
10. Film composite according to claim 9,
    characterised in that
    the adhesive layer (32) covers the whole area of the under side of the upper layer (33) of the film composite (30).
11. Film composite according to one of the preceding claims,
    characterised in that
    the overall area of the film composite (30) is slightly greater than the opening (11) to be covered including the peripheral edge (12).
12. Sealing disc for a container closure for use on a container with an opening bounded by a peripheral edge,
    characterised in that
    the lower areas of the sealing disc (20) comprise a film composite (30) according to one of the preceding claims.