WO2009065235A1

WO2009065235A1 - Method for producing a can and can produced by said method

Info

Publication number: WO2009065235A1
Application number: PCT/CH2008/000451
Authority: WO
Inventors: Martin Kleiner
Original assignee: O. Kleiner Ag
Priority date: 2007-11-20
Filing date: 2008-10-27
Publication date: 2009-05-28
Also published as: EP2214969A1; US20100276426A1

Abstract

The method is provided for producing a can (1), comprising a jacket-shaped can body (2), which has at least one opening (15) that is tightly closed by a peelable sealing membrane (8). The sealing membrane is provided with a pull tab (9), which is folded over and detachably connected to an upper side (11) of the sealing membrane (8). The pull tab (9) is detachably fastened to the upper side (11) of the sealing membrane (8) by means of an adhesive (10). The adhesive (10) is printed onto the upper side (11) of the sealing membrane (8) and/or onto the pull tab (9). The adhesive (10) is preferably a paint and in particular a sealing wax.

Description

A method of manufacturing a can and a can made by this method

The invention relates to a method for producing a can with a jacket-shaped can body, which has at least one opening which is sealed with a peelable sealing membrane and which is provided with a tear tab, which is folded over and releasably connected to an upper side of the closure membrane.

The invention also relates to a can which has been produced by this process.

In the prior art, such methods or cans have long been known. For example, CH 475 136 discloses a can having a closure membrane which is sealed to a retaining ring. The retaining ring has an annular, serving as a support for the sealing membrane inner part. The sealing membrane is made of aluminum foil or paper-laminated aluminum foil. By gluing or heat sealing, the sealing membrane is glued to the retaining ring. A pull tab serves to touch and pull off the sealing membrane from the retaining ring.

Another can has become known in the art from EP-AI 541 494. Again, the can is closed by a peelable sealing membrane. The peelable sealing membrane has a one-piece flap for opening the can. At such doses, the requirement is made that the tear tab is folded onto the lid surface. If the sealing membrane has a high proportion of aluminum, the tear-open tab can be folded so that it lies flat on the lid. Since the restoring force of a sealing membrane is low due to the high proportion of aluminum, the tear-open tab does not have to be fixed. It thus remains in the folded state even without fixation.

Increasingly, sealing membranes are required which have no or a comparatively small proportion of aluminum. Such closure membranes can be made of composite films with a high content of plastic and / or paper. The disadvantage here, however, that the folded flap must be fixed because the sealing membrane has a high restoring force. So far, hotmelt was used as an adhesive for fixing the tear tab. The adhesive is applied in a punctiform manner to the sealing membrane or to the tear-open tab. The disadvantage, however, is that hotmelt is sterilizable available, but difficult to order. In particular, closed systems are necessary.

The invention is based on the object to provide a method of the type mentioned, which enables sterilization of the can and yet is inexpensive to carry out.

The object is achieved in a generic method according to claim 1. In the method according to the invention, a sterilization-resistant adhesive is applied during the printing process. This adhesive can be applied for example by flexographic printing, digital printing or gravure printing. Such printing methods are particularly suitable for applying a sealing wax, which is resistant to sterilization.

The application of the adhesive is a printing process in the inventive method. This allows a more cost effective method. Since a sealing membrane with a smaller proportion or even without aluminum can be used in the process according to the invention, the proportion of waste can be substantially reduced. For example, closure membranes with a thickness of 0.05 mm may be used. The inventive method thus enables a cost-effective production of cans that can be sterilized and also can be opened in a simple manner with a tear-open.

According to a development of the invention it is provided that the tear tab is connected after folding by welding with the top of the closure membrane. The Welding or fixing the tear-open can be done very easily and quickly, for example, by ultrasound, a permanently heated bar or by means of a sonotrode. This process step can be carried out very inexpensively in line with the lid manufacturing process.

According to a development of the invention, the closure membrane is made of a composite film. This has, for example, one or more layers of polyester, a comparatively thin layer of aluminum, the pressure layer and a layer which connects the closure membrane peelably with the retaining ring.

The can according to the invention is characterized in that the adhesive is arranged as part of an imprint on the closure membrane and / or the tear-open tab and this releasably connects the bent tear-open tab to the upper side of the closure membrane. The adhesive as part of the imprint may in itself have any shape. It may, for example, be punctiform or linear. Preferably, this is a sterilized can, which is intended to receive a food.

Further advantageous features emerge from the dependent claims, the following description and the drawings.

Embodiments of the invention will be explained in more detail with reference to the drawing. Show it:

1 shows a partial section through an inventive box,

Figure 2 is a plan view of a portion of the top of the closure membrane

Figure 3 is a section through an inventive box and

Figure 4 is a section through a part of the sealing membrane and

Figures 5 a - 5c schematically sections through variants of the closure membrane. The box 1 shown in section in Figure 3 has a can body 2, which has a jacket 4, which is for example cylindrical or rectangular. The can body 2 has a bottom 3 and against this a retaining ring 6, which is placed tightly on the jacket 4. The jacket 4 may be made of any suitable material, such as tinplate, steel, plastic or coated paper. The retaining ring 6 may be uncoated, coated or painted. It can be made of tinplate, steel or aluminum, for example.

According to FIG. 1, the retaining ring 6 has an inwardly directed flange 7, which protrudes substantially vertically from an upper edge 5 of the jacket 4. On this flange 7 a sealing membrane 8 is peelable or peelable attached. The peelable fastening of such a closure membrane 8 is known to the person skilled in the art and therefore need not be further explained here.

The closure membrane 8 is made of a composite film which, for example according to FIG. 4, has a pressure A and layers B and C. The total density of the sealing membrane 8 is for example 0.05 mm and in particular 0.03 to 0.15 mm. The uppermost layer A forms the pressure with which an upper side 11 of the closure membrane 8 is printed and can represent, for example, a photograph as well as information about the contents of the can 1. The print can be gravure, digital or flexo. The layers B and C may be made of plastic films, for example polyester, paper or aluminum. There are also other layers conceivable, for example, a layer of PP-peel.

When printing on the sealing membrane 8, an adhesive 10 is simultaneously applied to the layer B. FIG. 4 shows the adhesive 10, which is in the region of the layer A. The adhesive 10 is applied to the layer B, for example with a gravure roll. This is preferably done simultaneously with the application of the pressure A. The adhesive 10 is preferably a sealing wax, which may be one or more components. An adhesive 10 or sealing wax which can be sterilized is preferably used. It is also conceivable, however, a non-sterilizable adhesive 10. The sterilization temperature is for example 128 ° Celsius degrees. The adhesive 10 is produced, for example, based on a polyester resin, polyester copolymer, polyurethane or PVC.

The adhesive 10 is used for releasably fixing the folded or folded according to Figure 1 tear tab 9. The tear tab 9 is thus in the closed state of the can 2 in the in Figure 1 shown folded or folded position fixed. This even if the closure membrane 8 is made of a composite film which has a high restoring force. Without this adhesive 10, the tear tab 9 would protrude from the top 11. The adhesive 10 is disposed between the tear tab 9 and the top 11 in a region IIa. The adhesive 10 may be applied to the top 11 and / or top of the tear tab 9. After printing on the sealing membrane 8 and sealing the sealing membrane 8 onto the retaining ring 6, the tear-open tab 9 is bent over into the position shown in FIG. By welding, the tear tab 9 is fixed in the position shown. Welding creates a releasable adhesion between the printed adhesive areas or an adhesive area and a surface. This can be done in a conventional manner, for example with a permanently heated bar or ultrasound. Preferably, the closure membrane 8 is connected to the retaining ring 6 prior to joining the tear-open tab 9.

In the embodiment shown in FIG. 5a, the adhesive 10 is printed separately to form a further print A 'on the upper side of the uppermost layer B. The layer B is here, for example, a film made of polyester. In principle, the further pressure A 'could also be omitted.

In the embodiment according to Figure 5b, the adhesive 10 is printed on to a further print A "In the production of the closure membrane according to Figure 5b, first the print A" is printed on the layer B and then the adhesive 10 is printed on the print A ".

In the embodiment according to FIG. 5 a, a further print A "is printed on the lower side of the layer B or on the upper side of the layer C, while the adhesive is printed on the upper side of the layer B.

In order to open the can 2, the tear-open tab 9 according to FIG. 1 is grasped by hand and pivoted upwards in the direction of the arrow 14. If the tear tab 9 according to FIG. 3 is then pulled in the direction of the arrow 13, then the closure membrane 8 can be completely pulled off the front retaining ring 6. The can 2 now has an opening 15 through which the contents of the can 2 can be removed. Of course, the sealing membrane 8 can also only be partially removed. A reclosure of the can 2 is possible for example with a lid, not shown here, which can be applied to the retaining ring 6. LIST OF REFERENCE NUMBERS

1 can

can body

ground

coat

5 edge

6 retaining ring

7 flange

8 sealing membrane

9 tab

10 glue

11 top

12 bottom

13 arrow

14 arrow

15 opening

A pressure

B layer (foil)

C layer (foil)

Claims

claims

1. A method for producing a can (1) having a jacket-shaped can body (2) having at least one opening (15) which is sealed with a peelable sealing membrane (8) and which is provided with a tear tab (9) folded over and with a top (11) of the closure membrane (8) is detachably connected, characterized in that applied to the top (11) of the closure membrane (8) and / or on the tear tab (a) an adhesive (10) by a printing operation and that with this adhesive (10) the tear tab (9) releasably connected to the top (11) of the closure membrane (8) is connected.

2. The method according to claim 1, characterized in that the adhesive (10) is a paint and in particular a sealing wax.

3. The method according to claim 1 or 2, characterized in that the adhesive (10) by gravure printing, flexographic printing, digital printing, screen printing or offset printing is printed.

4. The method according to any one of claims 1 to 3, characterized in that the tear-open tab (9) after being folded by welding with the top (11) of the closure membrane (8) is connected.

5. The method according to any one of claims 1 to 4, characterized in that the can (2) is sterilized with the applied closure membrane (8).

6. The method according to any one of claims 1 to 5, characterized in that the closure membrane (8) is made of a composite film having a plurality of layers.

7. The method according to claim 6, characterized in that the composite film has at least one layer of plastic.

8. can prepared by the method according to any one of claims 1 to 7, characterized in that the adhesive (10) is printed.

9. Box according to claim 8, characterized in that the closure membrane (8) is made of a composite film.

10. Box according to claim 8 or 9, characterized in that the closure membrane (8) is peelably connected to a retaining ring (6).

11. Box according to one of claims 8 to 10, characterized in that the closure membrane (8) has a high restoring force.

12. Box according to one of claims 8 to 11, characterized in that the adhesive (10) is sterilization resistant.

13. A can according to any one of claims 8 to 12, characterized in that the closure membrane (8) has an upper layer (B) and that the adhesive separated from a further pressure (A ') on the upper side of this upper layer (B) is.

14. Box according to claim 13, characterized in that the further pressure (A ") is arranged on the underside of the upper layer (B).

15. Box according to one of claims 8 to 12, characterized in that the adhesive (10) on the top of a print (A ") is printed.