EP1843865B1 - Method for producing a twist-off cap for a container and corresponding twist-off cap for a container - Google Patents

Abstract

The invention relates to a method for producing a twist-off cap (1) for a container, whereby the twist-off cap (1) is stamped out from a sheet metal and a peripheral wall (3) having a rolled-up rim (5) is formed on a bottom (2) and a sealing element (10) is applied. Said sealing element (10) is applied to the metal sheet prior to forming and the sealing element (10) is arranged so as to extend into the rolled-up rim (5).

Description

The invention relates to a method for producing a container rotary closure cap, wherein the container rotary closure cap is punched out of a metal sheet and formed on a bottom of a peripheral wall with a rolled edge and attaching a seal. Furthermore, the invention relates to a container rotary closure cap having a bottom, an adjoining the ground and angled relative to the ground peripheral wall having a rolled edge at its free end and surrounding an inner side, and a seal (see, eg DE-A-2924589 ).

Many food containers, in particular glass containers, such as jam jars, jars, jars for baby food, juice bottles, etc., are closed with a twist-lock. In such a rotary closure, a capsule covering a container opening is mounted on a container neck. In general, at Closing or thereafter creates a negative pressure in the container, so that the cap is "sucked" on the front side of the container neck. Such a rotary closure is accordingly also referred to as a "vacuum rotary closure". To open the container, the cap is rotated relative to the container. Such closures are also referred to as "twist-off closures".

The capsule is formed from a metal sheet. A blank required for molding the capsule is punched out of a sheet which is in the form of a tablet. When punching and the peripheral wall can be bent. In further operations then the free end of the peripheral wall is rolled. Finally, the cap is provided with a seal when completed. The sealing material is in this case mounted on the inside of the soil over part of the area in the container mouth region up to the transition region between the bottom and the peripheral wall. Partly the seal is applied only over part of the area. The seal is made of elastic material that can create at the mouth of the container to be sealed for sealing.

For the introduction of the seal technically very complex machine equipment are required after the punching and forming process, which usually have a much lower performance than the punching device. After the punching and forming machines, therefore, several following machines for introducing the sealant are arranged. After the introduction of the sealant, a thermal treatment for polymerizing the sealant is required. This results in a significant environmental impact. The Material selection is very limited for procedural reasons. It is therefore almost exclusively used a PVC foam.

The invention has for its object to be able to produce a container rotary closure cap cost.

This object is achieved in a method of the type mentioned by the features of claim 1.

Thus, it still has two manufacturing sections to produce the container rotary closure cap, which will also be referred to briefly as a cap, and provided with a seal. In a manufacturing section, the cap is punched out and shaped. In the other manufacturing section, the seal is attached. The fact that the sequence of the two manufacturing sections reversed, but can gain a considerable time and cost advantage. The application of a seal on an otherwise flat surface is much easier than the introduction of a seal in an already finished cap. The subsequent forming is not disturbed by the applied seal. Since the seal extends into the rolled edge, it is not necessary to apply the seal with an excessively high accuracy. Accordingly, the application of the seal can be done with a low-cost and fast-working device.

In general, therefore, it is sufficient to assign a group of machines that cause the blanking of a blank from the sheet and the forming, even a device for applying the seal on the plate. In addition, the training has the advantage that the seal is well secured against leaching in the rolled-edge, because no edge of the seal is freely accessible.

The seal is laminated in the form of a sealing foil on a panel or band-shaped blank. The sealing film can be removed, for example, from a roll. For laminating, it is basically only necessary to pass the sheet metal plate or sheet metal strip together with the sealing film through the nip of a pair of rollers and there to apply an increased pressure and optionally an elevated temperature. A stamp-like press is also suitable for laminating or laminating a sealing film onto a metal sheet. Then, when punching and forming the cap from this composite material, it has on its inside the seal which not only extends into the rolled edge, but practically closes with the peripheral edge of the cap. This has other advantages. A fully laminated inside cap is at the same time esthetic for a glass container. The risk of splintering glass when closing is significantly minimized. The seal is lying in another area at the mouth of the container. The risk of rust on the inside of the cap, even at the edge, is greatly minimized. The cap is also more suitable for PET bottles, as it can adapt to the mouth of the container through the flat elastic layer. The production is safer, since it can practically no longer occur that a cap has no seal. So there is less committee.

Preferably, a multilayer film is used as the sealing film. If you use a film as a seal, then you can achieve by adapting the sealing film adaptations to different requirements. In a multilayer film, the construction of individual layers can fulfill various requirements. In a multilayer film, the individual layers need not be clearly separated. Accordingly, one can use relatively inexpensive sealing films.

It is also preferred that an external coating in the form of a film is applied before forming on the side of the sheet opposite the gasket, which extends into the rolled edge. Just like on the inside of the sealing film can be applied to the outside of a film, which is then a replacement for the previously used-printing the cap. The film on the outside can then emboss the outer appearance of the cap. For example, there may be printed the name of the manufacturer or the type of goods received in the container. If the film is on the outside also in the rolled area extends into it, so the sheet of the cap on the Au-. completely covers the outside, then it protects against rusting. The handling of the caps in an automatic handling device is simplified because one can configure the film so that adjacent caps do not adhere to each other or get caught with each other.

The object is achieved in a container rotary closure cap of the type mentioned by the features of claim 5.

As a result, the seal is better retained on the cap. The sealing properties are improved because the seal rests in a larger area at the mouth of the container, for example a beverage bottle, a jam jar, a canned glass or a baby soft food container. The increase in the extent of the seal is gentle on the mouth of the glass container. The risk of splintering glass when closing is significantly minimized. The corrosion behavior of the cap is improved over the paint layer previously present on the inside.

It is preferred that the seal extends to the completion of the rolled-up edge. This greatly minimizes the risk of rust formation on the inside of the cap. It is much easier to apply such a gasket prior to molding the cap, because the gasket can easily be left over the area before molding, from which the cap will later be formed.

Preferably, the seal is formed by a sealing film applied to a blank from which the cap is formed. As explained above in connection with the method, the application of the seal can thereby be simplified to a considerable extent. You just have to apply the sealing film on a metal sheet or a sheet metal strip. Such a process can be well automated on the one hand. On the other hand, it can be accomplished with relatively simple devices. Basically, you only have to run the sealing foil together with the board or the band through a press. In this embodiment, although the waste that arises after punching, be covered with a film. But you can easily accept this. In finished caps, however, the seal is additionally held by the rolled-up edge, i. there is no area where you have free access to the seal from the outside to detach it.

Preferably, the sealing film is formed as a multilayer film. In a multilayer film, one can achieve adaptations to different requirements through the individual layers.

It is preferred that the sealing film is formed at least over part of its thickness by a foam-like material. By such a foam-like material, for example in the form of a foam core, a good flexibility of the sealing film is achieved. This improves the installation of the sealing film to the container mouth.

The sealing film preferably has a metallized barrier layer on its side facing away from the bottom. Such a barrier improves the seal against the container. For example, such a barrier layer prevents oxygen from the air from diffusing through the plastic forming a major constituent of the film into the interior of the container. In addition, the rotational behavior, for example when opening, can be favorably influenced. If the outer coating engages over the curled edge, you can influence the friction behavior between the lid and container by choosing the appropriate material.

It is also preferred if the cap has an outer coating on an outer side separated from the inside by the bottom, which overlaps the rolled-up edge. Such outer coating can replace the previously used paint. The fact that the outer coating engages over the edge to its non-visible edge, so the sheet covers the entire surface, the risk is small that you accidentally solve the outer coating. You can already provided the outer coating before applying to the cap with the desired optical design, for example, printing. It is much easier to print on a two-dimensional coating than a three-dimensionally shaped cap. Even so, the costs can be kept small. As a barrier layer can be used, for example, an aluminum foil. But it is also possible to evaporate a metal, such as aluminum, as a barrier layer.

Preferably, the outer coating is formed by a film which is applied to the blank. For example, such a film on the outside can also be laminated or laminated onto the metal sheet or the sheet metal strip. The outer coating is then punched out together with the inner coating and the material of the cap and simultaneously formed into the cap.

Fig. 1

eine erste Ausführungsform einer Behälter- drehverschluß-Kappe, teilweise im Schnitt,

Fig. 2

eine zweite Ausführungsform einer Behälter- drehverschluß-Kappe, teilweise im Schnitt,

Fig. 3

ein Detail X der Kappe einer ersten Ausfüh- rungsform,

Fig. 4

das Detail X der Kappe einer zweiten Ausfüh- rungsform,

Fig. 5

das Detail X der Kappe einer dritten Ausfüh- rungsform und

Fig. 6

eine schematische Darstellung zur Erläuterung der Herstellung der Kappe.

The invention will be described below with reference to preferred embodiments in conjunction with the drawings. Herein show:

Fig. 1

A first embodiment of a container turn-cap, partially in section,

Fig. 2

A second embodiment of a container turn-cap, partially in section,

Fig. 3

a detail X of the cap of a first embodiment,

Fig. 4

the detail X of the cap of a second embodiment,

Fig. 5

the detail X of the cap of a third embodiment and

Fig. 6

a schematic representation for explaining the production of the cap.

Fig. 1 shows a first embodiment of a container rotary closure cap 1, partially in section. The container rotary cap 1 is also abbreviated to "cap 1" in the following.

The cap 1 has a bottom 2, which merges into a peripheral wall 3. The peripheral wall 3 is angled relative to the bottom 2 by about 90 °. The transition between the bottom 2 and the peripheral wall 3 takes place here via an inclined surface 4 Fig. 2 illustrated alternative embodiment, the transition can also take place via a curvature 4 '.

The peripheral wall 3 is at its free, ie in Fig. 1 rolled up lower end, ie, it has a curled edge 5 on. The edge 5 surrounds a circumferential cavity 6, which is enclosed by the peripheral wall 3. The cavity 6 may be open to the bottom 2, as in the embodiment of the Fig. 1 the case is. However, the cavity 6 may also be closed, as in the embodiment of the Fig. 2 is shown.

Distributed in the circumferential direction, the edge 5 has a plurality of radially inwardly directed projections 7, which can engage in a thread on a container, not shown. In the embodiment according to Fig. 2 Such protrusions 7 are dispensable when the container neck is formed accordingly. The cap 1 can be solved in any case by turning the container neck.

The peripheral wall 3 surrounds an inner side 8 of the cap 1. Accordingly, outside of the cap 1, an outer side 9 is formed. The term "inside" and "outside" refers not only to the bottom 2, but to the complete cap 1.

On the inside 8 a seal 10 is arranged. Like from the Fig. 3 to 5 can be seen, this seal can have 10 different configurations. All embodiments have in common, however, that the seal 10 is not limited to the bottom 2, but on the inclined surface 4 and the curvature 4 'out into the peripheral wall 3 and there is continued into the rolled-up edge 5, so that the seal 10th practically closes with the edge of the curled edge. This requires that the seal 10 is deformed together with the edge 5. There is nowhere an area available where you could engage in the contact area between the seal 10 and the plate of the cap 1 to release the cap. In the embodiment according to Fig. 2 the edge 5 is even bent back on itself, so clamps the seal 10 in addition.

The outside 9 of the cap 1 is provided with an outer coating 11. The outer coating 11 extends over the entire outer side 9 of the cap 1, that is, over the rolled-up edge 5, and covers the entire outer side 9 of the cap 1 over its entire surface.

The preparation of such a cap is based on the schematic representation of Fig. 6 explained.

A metal sheet 12 or a sheet metal strip is passed through a laminating device 13. The laminating device is shown schematically here with two rollers 14, 15, which form a nip 16, through which the metal sheet 12 is passed. However, the laminator can also be formed in other ways, such as a press that works with stamping.

Before the laminating device 13, a roller 17 is arranged, from which the seal 10 in the form of a sealing film 18 is withdrawn. The sealing film 18 passes through the laminating device 13 together with the metal sheet 12 and is laminated there onto the metal sheet 12.

Before the laminating device 13 on the roller 17 of the sealing film 18 opposite side of the metal sheet 12, a roller 19 is disposed, from which a film 20 is removed, which forms the outer coating 11 of the cap 1. In one operation, so the sealing film 18 and the film 20 is laminated to the metal sheet 12.

The composite material of sheet metal 12, sealing film 18 and foil 20 thus formed is guided by a punch 21, which punches both the material required for the production of the cap 1 from the metal sheet 12 in one operation and the cap 1 in a preliminary stage of Fig. 1 shown form brings. In this case, not only the sheet of the metal sheet 12 is transformed, but also the laminated on the metal sheet 12 sealing film 18 and the film 20. The film 20 may be unnecessary. For the sake of simplicity, it is shown that the punch 21 immediately follows the laminator. As a rule, however, the laminated metal sheet will be left to rest for a predetermined time, for example 24 hours, so that the between the Films and the sheet arranged laminating adhesive reaches its final strength.

The punch 21 is followed by another machine 31, which ultimately winds the edge 5. This machine 31 is shown here as a single machine. However, it can also be integrated into the punch 21 or be formed from a plurality of individual forming machines.

Also in the machine 31, the sealing film 18 and the film 20 are formed together with the sheet, which ultimately forms the cap 1.

The Fig. 3 to 5 Now show different embodiments of caps in a detail X. The same parts are denoted by the same reference numerals as in the Fig. 1, 2 and 6 Mistake.

Shown is the section of the bottom 2, which is formed as a supporting element mainly of a metal sheet 22. In the Fig. 3 However, layering shown continues over the entire material of the cap 1, ie also in the edge 5.

The sheet 22 has on its outside the film 20 and on its inside the sealing film 18.

The foil 20 can carry any desired print. It can be formed by a relatively thin plastic film.

The sealing foil 18 is suitable for sealing. Accordingly, it has a thickness of, for example, at least 250 microns and a suitable elasticity. Both the sealing film 18 and the film 20 may be connected to the sheet 22 with suitable laminating adhesives. Even when laminating adhesives are used, any heat processes required, for example pasteurization, after the filling and closing of a container can take place.

The sealing film 18 may in this case, depending on the material used or according to the requirements of the cap 1 be compact or foamed. The foaming need not pass over the entire thickness of the sealing film 18.

In Fig. 3 the sealing film 18 is shown with a layer.

One can, however, as from the 4 and 5 also uses multilayer films. So shows Fig. 4 an embodiment in which the film 18 has a carrier region 23 with a greater thickness, which may be foamed, for example, and a metal layer 24, for example an aluminum foil, or a metallized layer, for example a vapor-deposited film. The metallized layer prevents, for example, that oxygen from the air can pass through the carrier layer 23 into the interior of the container closed with the cap 1.

Fig. 5 shows a film 18 which is composed of three layers, namely the mentioned carrier layer 23, the metal layer 24 and a fixing layer 25.

Depending on the desired requirements for the sealing film 18, the skilled person will select a suitable structure of the sealing film 18 with one or more layers.

The advantages of such a cap are obvious. One can accomplish the sealing film 18 and optionally also the film 20 as outer coating by laminating a sheet metal plate 12 on efficient tape or sheet laminating 13. Such a laminating system 13 can handle the same throughput as the downstream punch 21. Accordingly, a lesser mechanical complexity is required.

There are no complicated manufacturing equipment for introducing a seal into a single cap 1 is required. This gives a greater choice of material for the seal 10. Thus, the cap 1 is better adapted to individual requirements. The manufacturing process for the cap 1 is reduced to a minimum. It results in a very small footprint and a significantly lower energy consumption. A full-surface laminated cap 1 is at the same time for the container, such as a glass container, muzzle friendly. The risk of splintering glass when closing is significantly minimized.

The seal abuts in a wide area at the mouth of the container. The risk of rust formation on the inside is greatly minimized. If a film 20 is used as an outer coating, this also applies to the outer coating. The film 20 can during punching even drawn to the cutting edge created during punching. Even if the film 20 only partially covers this cut edge, it improves the corrosion protection. The cap 1 is also better suited for PET bottles, since they can adapt to the mouth of such a container by the flat elastic seal 10.

By forming the outer coating 11 as a foil 20 saves energy and time. There are only two operations required, namely the production of the film and the application of the film 20 on the metal sheet 12. So far, many more operations were required, namely the priming, printing and silver painting of the cap, wherein a thermal treatment was required, the is correspondingly energy-consuming.

The production of such a cap is associated with a lower environmental impact than before. The sealing film 18 and the film 20 only have to be applied to the sheet and optionally glued there. A thermal aftertreatment is not required or only to the extent necessary to cure the laminating adhesive between the films 18, 20 and the sheet 22. For the energy demand is expected to be only a fraction of that of today's facilities. It is also conceivable that a punching machine can work not only with metal sheets, but from the tape.

Claims (11)

1. Method for producing a twist-off cap for a container, in which the twist-off cap for a container is punched out of sheet metal, and a peripheral wall with a rolled edge is formed on a bottom and a seal is applied, wherein the seal is arranged in such a manner that it extends into the rolled edge, characterized in that the seal is applied to the sheet metal prior to the forming operation, the seal being laminated in the form of a sealing film onto a tabular or strip-shaped blank.
2. Method according to Claim 1, characterized in that the seal is applied before the punching-out operation.
3. Method according to Claim 1, characterized in that a multi-layer film is used as the sealing film.
4. Method according to one of Claims 1 to 3, characterized in that, prior to the forming operation, an external coating in the form of a film which reaches into the rolled edge is applied on that side of the sheet metal which lies opposite the seal.
5. Twist-off cap for a container, with a bottom (2), a peripheral wall (3) which adjoins the bottom (2) and is angled in relation to the bottom (2) and has a rolled-in edge (5) at its free end and surrounds an inner side (8), and a seal (10) which extends into the rolled-in edge (5), characterized in that the seal (10) is formed by a sealing film (18) which is applied to a blank from which the cap (1) is formed.
6. Twist-off cap for a container according to Claim 5, characterized in that the seal (10) extends as far as the end of the rolled-in edge.
7. Twist-off cap for a container according to Claim 5, characterized in that the sealing film (18) is designed as a multi-layer film.
8. Twist-off cap for a container according to Claim 5 or 7, characterized in that the sealing film (18) is formed over at least part of its thickness by a foam-like material.
9. Twist-off cap for a container according to one of Claims 5 to 8, characterized in that the sealing film (18) has a metalized blocking layer (24) on its side facing away from the bottom (2).
10. Twist-off cap for a container according to one of Claims 5 to 9, characterized in that its outer side (9) which is separated from the inner side (8) by the bottom (2) has an external coating (11) which fits over the rolled-in edge.
11. Twist-off cap for a container according to Claim 10, characterized in that the external coating (11) is formed by a film (20) which is applied to the blank.

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