EP0408831A1 - Easy-open closure for packages, especially beverage cans - Google Patents

Abstract

A tear-off closure is provided which consists of a laminated material (20) having at least two load-carrying layers (21, 22) and a layer (23) connecting the latter. The laminated material is correspondingly grooved or notched to expose a press-in or tear-off opening. In this case, two groove or notch lines (13, 14) are provided which extend parallel to each other with a predetermined mutual spacing (27) and are indented or worked into the laminated material (20) from opposite sides of the closure, each notch line (13, 14) extending into the material connecting the load-carrying layers so that the separation operation during opening does not take place, as is usual, approximately perpendicular to the plane of the closure, but parallel to said plane inside the laminated material. <IMAGE>

Description

The invention relates to an easy-to-open lid for packaging, in particular beverage cans, with the features of the preamble of claim 1.

Such covers have long been widely used and in various embodiments. The lids are made of sheet metal and either have a tear-open area delimited by a score line with a grip tab, with the aid of which a pouring or drinking opening is exposed by tearing open. However, tear-open covers are also known which have a pre-punched opening which is then sealed from the inside and / or outside, but can be torn open. Plastic masses or composite foils are used for sealing, which are glued to the edge of the pre-punched opening. However, it is also known to leave the punched sheet metal area permanently but bendably connected to the cover mirror and to deform or widen the edge of the punched-out part and / or the edge of the opening such that the punched-out sheet metal part and the The edge of the opening should lie in mutual overlap and be connected and sealed with a plastic material.

The latter covers are characterized by a relatively low opening resistance, so that the opening process is made considerably easier. This is of great advantage for the handling of cans sealed with such lids by children or women. However, the lids with a pre-punched opening have in some cases not proven to be sufficiently resilient, since they, especially with alternating loads, e.g. Changes in temperature and / or pressure that can leak.

It is an object of the invention to develop an easy-to-open lid with the features of the preamble of claim 1 so that, on the one hand, the risk of leakage is largely eliminated even with higher loads or alternating loads, and yet there is a reduced opening resistance which facilitates opening.

This object is achieved by the teaching of claim 1.

In this version there is no punching of the cover material. Also in the area between the two punching lines, the layers absorbing the loads on the opposite sides of the cover are firmly and sealingly connected to one another via an adhesion-promoting layer or a further plastic layer or the like. Tightness problems can therefore not occur even when the cover is subjected to alternating loads. Nevertheless, the opening resistance of the opening or indentation area is low since no material layer or residual material thickness has to be broken in and torn open. Another important advantage is that the choice of the material of the layer to which the scoring or notching lines extend and / or the mutual spacing of the scoring or notching lines make the opening resistance of the cover very precise in the manufacture of the cover can be set.

The selection of the material for the layers of the layer material that absorb the loads is also simplified to the extent that the question of breaking through or tearing through this layer of material no longer plays a role. The materials for these layers can therefore be selected from the point of view of cost and strength and the ability to withstand alternating loads.

The new lid is suitable for opening to the outside with the help of a grip tab and folding over the tear area on the outer surface of the lid. However, the lid can be designed as a lid which can be opened by being pressed in, in which the region exposing the opening is pressed into the interior of the can and folded over.

The subclaims relate to advantageous developments and embodiments of the teaching of claim 1.

The invention is explained in more detail below with the aid of schematic drawings using several exemplary embodiments.

• Figur 1 im Ausschnitt das Ende einer mit einem Deckel gemäß der Erfindung versehenen Behälters, wie Getränkedose;
• Figur 2 im Ausschnitt und in Draufsicht den Deckel gemäß der Erfindung;
• Figur 3 im größeren Maßstabe einen Querschnitt entlang der Schnittlinie III-III der Figur 2;
• Figur 4 einen Längsschnitt der Schnittlinie IV-IV der Figur 2 bei geschlossenem Deckel;
• Figur 5 in ähnlicher Darstellung wie Figur 4 den Deckel während des Freilegens der Deckelöffnung;
• Figur 6 im Ausschnitt den Querschnitt eines abgewandelten Ausführungsbeispieles des Deckels nach der Erfindung und
• Figur 7 in Draufsicht eine Abdecklasche, wie sie bei der Ausführung nach Fig. 6 verwendet werden kann.

Show it:

• 1 shows in detail the end of a container provided with a lid according to the invention, such as a beverage can;
• Figure 2 in section and top view of the lid according to the invention;
• Figure 3 on a larger scale a cross section along the section line III-III of Figure 2;
• 4 shows a longitudinal section of the section line IV-IV of Figure 2 with the lid closed;
• Figure 5 in a similar representation as Figure 4, the lid while exposing the lid opening;
• Figure 6 in section the cross section of a modified embodiment of the lid according to the invention and
• 7 shows a top view of a cover flap, as can be used in the embodiment according to FIG. 6.

The lid is suitable for two or three-piece cans. In Figure 1 it is assumed that the can 1 consists of a deep-drawn and ironed aluminum or steel sheet. The lid 3 can be sealed and permanently connected to the body 2 of the container in any manner, in particular also, as shown, via a double seam 4. The container axis is designated 6.

In the lid according to FIG. 2, it is assumed that it has two indentation areas, namely an indentation area 8 for ventilating containers under excess or negative pressure and an area 9 for exposing a pouring opening. The lid has an edge flange 4 for connection to the body 2 of the container 1. The two indentation areas 8 and 9 are provided in the cover mirror 7 in alignment along a diameter. Each indentation area is delimited by two scored or notch lines 13/14 and 17/18 running parallel to each other at a predetermined mutual distance. As is clear from FIGS. 2 and 3, the notch or scoring lines 13, 14 are not only not in mutual alignment but are also incorporated into the material of the cover mirror 7 from opposite sides of the cover. The same applies to the indentation area used for ventilation, which is delimited by two notch or scoring lines 17, 18 of smaller dimensions. To make it easier to press in, the press-in areas have projections 12 or 16, which correspond to the opening of the container with the finger or the thumb appropriate pressure can be exerted.

To ensure that the areas pressed into the interior of the lid when opening do not fall into the container contents, these areas remain integrally connected to the lid mirror 7 via bending lines 15 and 19, which are preferably smaller at the end of one area 11 than the other area 10 Width are provided.

The lid consists of a composite or layer material 20. This has at least three layers, as shown in FIG. 3. The two outer layers 21 and 22 are made of a material of sufficient strength to be able to safely absorb any increased internal pressure in the container or the loads occurring when the containers are stacked, as well as changes in load occurring due to temperature and / or pressure changes. The two layers 21 and 22 are connected to one another via a middle layer 23. This third layer 23 can consist of a plastic with high adhesion to the layers 21, 22, the cohesive force of which is however limited to a predetermined value, so that when shear forces occur in the area 27 between the two score lines 13, 14 or 17/18 Tear open plastic layer. The layer 23 can, however, also consist of a material of high cohesive force and tear resistance if it is ensured that the adhesive force between this layer 23 and one of the adjacent layers 21, 22 is limited to a predetermined value. Instead of a plastic layer, however, it is also possible to use an adhesive or similar adhesive layer with a predetermined adhesive force.

The composite material can also consist of more than three layers, provided that the condition of claim 1 is met.

It can be seen that the required breaking force can be influenced to a large extent by the choice of the material for the layer 23. Another way of influencing is to vary the mutual distance 27 between the score lines. Generally, this distance should be between 0.1 and 8 mm, preferably between 2 and 6 mm. It may be expedient to provide a narrowly delimited area on the circumference of the indentation area, which serves to initially break in when opening. In this area, the distance 27 between the score lines 13, 14 can be chosen to be smaller than in the other areas.

In the embodiment shown in Figure 3 it can be seen that when internal pressures P occur there is a high degree of security against accidental leakage, since the load-bearing layers 21 and 23 overlap in such a way that the outer layer 21 in the region 27 between the score lines and the inner layer 22 supports against the internal pressure P. In the case of containers with a good packed under vacuum, the relative position of the score lines or scoring lines 13, 14 can also be opposite, i.e. the score line 14 on the inside of the cover lies radially inside the other score line 13, so that the opening area can be torn outwards with the aid of a tab attached to it.

After scoring or notching the composite material, the outer surface and the inner surface of the cover are expediently provided, at least in the region of the notch lines, with a protective layer, such as a lacquer layer, which also fills and covers the notch lines, as is indicated in FIG. 3 at 25.

Different combinations of materials can be used for the composite. A material is preferred in which the load-bearing layers 21, 22 are made of metal, e.g. Aluminum, steel or tinplate exist. A layer 23 made of a material based on polyethylene and / or polypropylene can be used to connect the load-bearing layers.

To open the lid according to FIG. 2, the ventilation area is first pressed in by pressing on the projecting area 16. The other indentation area 9 is then exposed by pressure on the projecting area 12, as illustrated in FIGS. 4 and 5. It can be seen from FIG. 5 that none of the load-bearing layers 21, 22 is broken or torn open when opened. Rather, the opening process takes place by splitting the connecting layer 23 or by detaching this layer from one of the two adjacent layers. The opening edges 14a, 13b and the edges 13a, 14b of the indentation clearly show the gradation that arises here.

The break-in resistance can also be influenced by the geometric shape of the scribe lines or score lines.

In the embodiment according to FIGS. 6 and 7, the opening area 29 of the cover 30 is in turn delimited by two notch lines 36, 37 arranged at a mutual distance in the radial direction, which from opposite sides in the lid material is embossed, to the extent that the middle layer 33 of the lid material lying between the outer layer 31 and the inner layer 32 is not damaged. The opening area is preferably located in an outer recess or recess 34 in the cover, the dimensions of which are larger than the dimensions of the opening area.

In this embodiment, the opening area is covered from the outside by a tab 40 with a grip section 42. The edge area of the tab 40 is, with the exception of the grip section 42, along a self-contained strip area 43 with the outer layer 31 of the lid material, e.g. sealed and firmly connected by sealing. The tab 40 can consist of a simple material or a composite material, as shown. Within the annular sealing zone 43, the tab 40 has a line of weakness which merges into the longitudinal edges of the handle section 42 from both sides. The grip section 42 crosses the sealing area 43 and is peelably connected to the cover 30 in this crossing area. This can be done in that the sealing adhesive force in zone 43 is correspondingly reduced in the region of the intersection. However, the crossing region is preferably provided by a score line which is embossed into the inner layer of the tab body made of composite material and which is designated by 44 and which enables the region of the inner layer of the tab body 40 delimited by the score line 44 to differ from the other layers of the Tab body 40 peels off and remains firmly connected to the cover 30. For this purpose, the adhesive force between the inner layer and the next layer of the tab body 40 is correspondingly lower than the seal adhesive force in the crossing area.

In this way, the tab 40 can be separated from the sealing zone 43 with the aid of the grip section 42, so that the opening area 29 underneath is free. As in the exemplary embodiment described above, this can now be brought to break in by pressure from the outside and pivoted inwards. However, the tab 40 is preferably also permanently connected to the opening area 29 in the area within the radially outer score line 37 of the outer layer 31 of the cover 30, so that when the tab 40 is torn open with the aid of the handle section 42, the opening area also 29 is also separated from the lid, in a manner similar to that described with reference to the embodiment according to FIGS. 2 to 5. It should be noted that in this case the radially outer score line 37 from the outside and the radially inner score line 36 from the inside into the composite Material of the lid 30 is introduced.

Instead, a tab 40a could also be permanently and firmly connected to the opening area 29 over the entire area or via the sealing zone 46a, with the exception of the handle section 42a. In this case, the tab 40a only serves to reinforce the opening area and to facilitate opening to the outside.

In both cases, it is important that the sealing connection 46 or 46a between the tab and the opening area 29 extends at least at the level of the handle section 42, 42a to close to the outer notch line 37, preferably over the entire circumferential length of the notch line 37.

The score line 41 of the tab 40 can be interrupted in an area 41a opposite the grip section 42, so that the tab 40 and the opening area 29 firmly connected therewith remain firmly connected to the cover material 30 after the opening has been exposed.

Claims (16)

1. Easy-to-open lid for packaging, in particular beverage cans, which can be permanently connected to the edge of the can and which has at least one tear-open or indentation area delimited by a line of weakness for exposing an opening in the lid mirror, characterized in that it consists of a composite material and the opening area ( 10) is delimited by two scored or notch lines (13, 14) running parallel to one another at a predetermined mutual distance (27), which extend from opposite surfaces of the cover (3) to the area of a predetermined layer (23) of the composite material . 2. Lid according to claim 1, characterized in that the layer (23), up to which the two parallel scoring or score lines (13, 14) extend, consists of a plastic with a predetermined cohesive force. 3. Lid according to claim 1, characterized in that the layer (23) up to which the two parallel score or notch lines (13, 14) extend from a plastic with a predetermined adhesive force with respect to at least one adjacent layer (21 or 22nd ) consists. 4. Lid according to claim 1, characterized in that the two parallel scoring or score lines (13, 14) extend to an adhesion-promoting layer (23) with a predetermined adhesive force. 5. Lid according to claim 1, characterized in that the layer (23) up to which the two parallel score or score lines (13, 14) extend, consists of a gas barrier layer. 6. Lid according to one of claims 1 to 5, characterized in that seen in plan view from the inner surface of the cover (3) outgoing scribe or score line (14) from the outer surface scoring or score line (13) from the outside with Distance (27) surrounds. 7. Lid according to one of claims 1 to 5, characterized in that seen in plan view from the inner surface of the lid (3) outgoing scoring or score line (14) with a predetermined distance (27) within the scoring or score line (13) starting from the outer surface and the tear-open area (10) is provided with a tear-open handle. 8. Lid according to one of claims 1 to 7, characterized in that the mutual distance (27) of the score or score line (13, 14) in the break-in start area is smaller than in the other areas. 9. Lid according to one of claims 1 to 8, characterized in that the composite material consists of two outer metal layers (21, 22) and a plastic or adhesive layer (23) lying between them, up to which the scoring or notching lines (13 , 14) are sufficient. 10. Lid according to one of claims 1 to 9, characterized in that the outer surfaces of the lid (3) are covered at least in the area of the scoring or notching lines (13, 14) by a protective layer (25), in particular a lacquer layer. which also covers the scoring and notching lines (13, 14) to the outside. 11. Lid according to one of claims 1 to 10, characterized in that the center distance (27) of the scoring lines (13, 14) is between 0.1 and 10 mm, preferably between 2 mm and 6 mm. 12. Lid according to one of claims 1 to 11, characterized in that the opening region (29) of the lid (30) is covered from the outside by a tab (40) with a handle portion (42), the edge region (43) with the lid outside the scoring or notching line (37) introduced from the outside into the cover material is tightly and permanently connected by sealing and has a tearable weakening line (41) radially within the sealing zone which merges into the outline of the handle section (42). 13. Lid according to claim 12, characterized in that the line of weakness is introduced from the outside into the tab made of composite film material. 14. Lid according to claim 12 or 13, characterized in that the crossing area between the handle portion (42) and the sealing zone (43) is delimited by a score line (44) introduced from the underside of the tab made of composite material (40) and the composite material has an adhesive force between a layer lying on the underside and another layer which is less than the sealing adhesive force in the sealing zone. 15. Lid according to one of claims 12 to 15, characterized in that an area (46) of the tab (40) within the tearable line of weakness (41) is permanently connected to the opening area (29) of the lid (30). 16. Lid according to one of claims 1 to 11, characterized in that the opening region (29) of the lid (30) is covered from the outside by a tab (40a) with a grip portion (42a), the edge region of which is close to the opening region radially outer scoring or score line (37) is tightly and permanently connected by sealing.

Images