EP2208554B1 - Method and device for producing tear-open lids - Google Patents

Abstract

The method involves supplying a strip from tear-open foil material. A foil section (25) is punched out from the strip with a tear-open flap (29). An adhesive surface (30) is applied on the strip before the punching out of the foil section, when tear-open lids (28) of the bent tear-open flap come out. An independent claim is also included for a tear-open lid manufacturing device.

Description

background

The invention relates to a method for producing tear-open lids, according to claim 1. Furthermore, the invention relates to a device for the production of tear-open lids according to claim 7.

State of the art

It is known to carry out lid for can or can-like packaging as on the packaging top permanently attached metal lid, which have a cover ring with a removal opening. This remains closed until the first use of the contents of the package by means of a heat-seal applied to the cover ring, tear-away film; Such covers are referred to as tear-open. The film on the lid is called a tear-open film and can be, for example, a metal foil, a metal composite foil or a pure plastic foil. An additional, arranged over the metal lid lid made of plastic makes the packaging during the period of use of the contents again closed. To open the tear-open lid or to tear off the sealed-on foil, this has a tear-open tab. When closing a can after it has been filled, the prefabricated tear-open lids are crimped on the jacket of the can. In this manufacturing step, a protruding tear tab disturb, can crumple and can even be demolished. The application of the plastic lid is also usually only possible if the tab is bent back. It is therefore desirable that the tear tab is bent back onto the lid and maintains this position. This is possible with metal foils, but even with these doses during the sterilization of the filled and sealed can, the effect of heat and the cooling process can cause a deformation and an undesired protrusion of the pull-tab. For composite films made of metal and plastic or films only made of plastic, a permanent bending back is more difficult and there is still more likely to emerge during sterilization due to different thermal expansion of the layers. For doses receiving dry products, which need not be sterilized, it is already known, after sealing the tear-open film on the lid to fix the bent-back tear-open tab with hot-melt adhesive on the lid. However, this production step is expensive. In addition, it can not be used for cans to be sterilized, since hot-melt adhesive fails under sterilization conditions.

EP 1 386 852 A1 discloses a method of manufacturing tear-open covers in which a strip of tear-open film material is fed, a film section is punched out of the strip with a tear-open tab, and the film section is sealed onto a cover ring. Subsequently, an adhesive surface is attached to the tape prior to punching the film section and finally the tear tab is bent onto the lid, being attached thereto by means of the adhesive surface on the tape. The method enables easier and cheaper production of tear-open lids.

Out DE 10 2007 017 339 It is also known that the gripping portion of the tear-open foil can be fixed to the lid with a securing seal.

Known methods and devices for producing tear-open lids are described below with reference to FIGS. 1 to 9 explained in more detail. The FIGS. 2 to 8 serve to explain manufacturing steps.

Presentation of the invention

The invention is based on the object to provide an improvement in the production of tear-open lids.

To solve the problem in the aforementioned method, the application of an adhesive surface on the tape before punching the film section and at a point where the bent tear-open tab comes to lie in the finished tear-open lid. The adhesive surface is applied in the form of a piece of double-sided adhesive tape. The adhesive tape is provided on its upper side with a protective film, which is removed before bending over the tear-open tab. The protective film allows the trouble-free sealing of the tear-open film on the cover ring and protects the adhesive surface.

Furthermore, the object with the manufacturing apparatus according to claim 7.

An adhesive tape having a different adhesive force on the two adhesive sides is particularly preferred, the tape being applied in such a way that the lower adhesive force becomes effective in the tear-open tab.

Brief description of the drawings

• Figur 1 eine schematische Seitenansicht einer Vorrichtung nach Stand der Technik sowie zur Ausführung der vorliegenden Erfindung;
• Figur 2 bis Figur 8 Sektoren von Metalldeckeln zur Erläuterung von deren Herstellung;
• Figur 9 eine Draufsicht auf einen Aufreissdeckel gemäß der Erfindung;
• Figur 10 eine teilweise Schnittdarstellung des Aufreissdeckels von Figur 9;
• Figur 11 eine schematische Ansicht des Aufbringens der Aufreissfolie in der Siegelstation sowie weiterer Schritte;
• Figur 12 eine schematische Ansicht einer Stanzstation für ein doppelseitiges Klebeband;
• Figur 13 eine schematische Schnittansicht der Blas- und Saugeinrichtung zur Entfernung der Schutzfolie von der Klebefläche; und
• Figur 14 eine genauere Ansicht der Entfernung der Schutzfolie.

In the following, the prior art and embodiments of the invention will be explained in more detail with reference to the drawings. It shows

• FIG. 1 a schematic side view of a device according to the prior art and for carrying out the present invention;
• FIG. 2 to FIG. 8 Sectors of metal lids for explanation of their manufacture;
• FIG. 9 a plan view of a tear-open according to the invention;
• FIG. 10 a partial sectional view of the tear-open lid of FIG. 9 ;
• FIG. 11 a schematic view of the application of the tear-open in the sealing station and other steps;
• FIG. 12 a schematic view of a punching station for a double-sided adhesive tape;
• FIG. 13 a schematic sectional view of the blowing and suction device for removing the protective film from the adhesive surface; and
• FIG. 14 a closer view of the removal of the protective film.

Ways to carry out the invention

FIG. 1 shows a schematic side view of an apparatus 1 for the production of tear-open. This has on a machine frame 2 several processing stations 3 to 9. A conveyor 10, 13, 14 conveys lid parts and the finished lid in the conveying direction, which is indicated by the arrow C, from the beginning of the device at the stack 11 to the end of the device where the lid via slides into the trays 16 or 17 arrive. From the stack 11 lid parts are stacked in a known manner and get into the conveyor. This can have two each individually arranged laterally of the objects long rails 10 which lift the lying on shelves 10 'and in the stations 3 to 9 cover parts or cover when lifting the rods 10 by means of the drive 14 in the direction of arrow A upwards and then displace them forward by an amount in the direction of arrow B (rectified like the arrow C) by the crank drive 13 by an amount in the forward direction. Thereafter, the rods are moved in the direction of the arrow A down while the lid parts and lid are in turn stored on their filing points. The rods 10 are then moved backwards under the article storage positions in the direction of arrow B against the arrow C to then perform the process described again. The cover parts or cover rest between the transport on their storage positions or are located in the processing stations and are processed there. After a processing step by all processing stations, the renewed promotion. Instead of the described conveyor could a known conveyor with two timing belt according WO 2006/017953 be used. Such endless belt drive is provided in the necessary for the number of processing stations length and the stepwise, synchronized with the processing stations timing belt movement is by a Stepper motor or servomotor causes, which drives the toothed belt by toothed rollers. The conveyor with timing belt allows the production of lids with a higher number of cycles of eg 200 lids per minute.

FIG. 2 shows stacked metal lid blanks 20 as they are ready in the stack 11 at the beginning of the conveyor. These blanks 20 are for example round metal discs of eg 11 cm diameter. Of course, other basic shapes, such as square or rectangular discs and other diameters are readily possible. The blanks 20 are already in a processing machine, not shown, at its edge as in FIG. 2 shown preformed. In the FIG. 2 and the following ones FIGS. 3 to 9 In each case only one sector of the entire disc or the lid is shown to simplify the figures. In the first processing station 3 of FIG. 1 is punched by punching with top and bottom tool an opening in the disc, which in FIG. 3 it can be seen in which the edge of the opening is denoted by 21 and the punched round disc with 27. This disc 27 arrives as waste in the container 12 of FIG. 1 , This results in an annular cover part 20 'with an opening which forms the removal opening of the finished cover. The punching processing station 3 is - as is the case with the other stations - driven by a drive 15. At the processing station 4, the edge 21 is pulled down, whereby, for example, the in FIG. 4 shown shape 22 of the edge is achieved. The annular cover parts 20 'then pass into the sealing station 5. In this, a film section 25 is punched with punching means 6 and placed over the opening of the cover ring 20' and fixed there by heat sealing, which in the FIGS. 5 and 6 is apparent. The tear-open foil 25, which is a metal foil or composite foil or a plastic foil can be, is provided in a known manner on its underside with a sealable plastic layer. The tear-open film 25 can be, for example, a multilayer composite film with plastic layers and aluminum layers, for example having a layer of hot-sealable polypropylene (PP) on the underside of the cover and a following layer of PET followed by an aluminum layer which again is provided with a PET on the top side of the tear-off film Layer is provided. Any printing is then arranged under this PET layer. A further embodiment of the tear-open film may be a lid-side or filling material-side hot-seal lacquer layer followed by the aluminum layer and the top-side PET layer. Other embodiments are known in the art and can be used in the context of the present invention. The required, in this example round film blank 25 is usually stamped out of a wide film web in the station 5.6 and placed over the central recess of the annular disc and through the sealing station, the film at the edge of the circular recess of the cover part 20 'under heat pressed so that the film 25 is sealed to the metal lid portion 20 'by melting and subsequent cooling of the sealable layer. This is known and will not be explained here. Thus, the tear-open lid 28 is formed. For cooling, at most a cooling processing station 7 may be provided. In a processing station 8, the film 25 can be embossed 24 (FIG. FIG. 7 ), and it is further the edge 22 crimped to the finished edge 23. If the tear-open foil is provided with a tear-open tab, the tab can also be bent so that it comes to rest on the lid. In a likewise to be designated as a processing station test station 9, the finished lid are subjected to a test, which usually a leak test for the on the lid applied tearing film 25 includes what an air pressure difference between. Bottom and top of the lid is generated. If the film is tightly mounted on the cover ring, the cover enters the receptacle 16 for the finished cover. If a leak is detected, the lid passes over the other slide shown in the waste container 17th

FIG. 9 shows a finished Aufreissdeckel 28 in plan view. In this, the tear-open film 25 is provided with a pull-tab 29, which is bent back onto the lid. According to the invention, the tear-open tab is fastened to the cover with an adhesive surface 30, which according to the invention is formed by a double-sided adhesive tape, in particular with different adhesive force of the two hinge sides. It can also be provided an adhesive surface, which is formed by a sealing wax. FIG. 10 shows an enlarged view of the region of the tear-open with the pull-tab 29, which is fastened in the bent-back position detachably on the adhesive surface formed by a piece of double-sided adhesive tape. The tab 29 projects beyond the adhesive surface 30, so that the tab can be easily grasped for opening the tear-open lid and detached from the adhesive surface 30. In this case, the adhesive tape 33 is preferably adhesively bonded to different degrees on both its sides, so that the adhesion of the adhesive tape to its underside (in the FIG. 10 seen) or at the Aufreissfolienfläche is greater than at its top, where the tear-open tab 29 is held adhesive. This ensures that the tab 29 can be easily detached from the adhesive surface while the adhesive tape remains adhered to the tear-open foil of the lid. The edge of the removal opening is provided in this example with a different shape 23 'as in FIG. 7 ,

Based on FIG. 11 the procedure for providing an inventive adhesive surface 30 in the form of a piece of double-sided adhesive tape on the Tear open explained. Other types of adhesive surfaces, in particular sealing wax surfaces, can also be applied. FIG. 11 shows roughly schematically a part of a device for the production of tear-open, which, for example, a device according to FIG. 1 is. With the in FIG. 11 Not shown conveyor 4 rows lid parts 20, 20 'and cover 28 are conveyed parallel in the conveying direction C. In the area of the sealing station not shown in the apparatus (corresponding to the sealing station 5 and 6 of FIG. 1 ), a belt 35 of the tear-open film material enters the sealing station and is punched there to form the film sections 25 with the tear-open tab 29. The stamping is chosen so that as little as possible stamping waste remains. The film sections 25 for in the FIG. 11 top row of the cover rings 20 'are punched in this example in the band 35 in the leftmost row at the edge of the band. There remain the vacancies 25 'thereafter. The foil sections 25 for the second top row of lid rings 20 'are punched in the row to the left of the central longitudinal axis of the band 35 and the foil sections 25 for the second bottom row of lid rings 20' are punched out in the row to the right of the central longitudinal axis of the band 35. The foil sections 25 for the bottom row of cover rings 20 'are punched out in the rightmost row of the strip 35. The punched-out foil sections are each sealed onto the associated cover ring, as is known to the person skilled in the art. The belt 35 may be conveyed by drive rollers 36 or in other known ways. Before the punching of the film sections 25, the adhesive surfaces 30 are applied to the belt 35 on its upper side 26. This is done so that at least one such adhesive surface is applied to the tape 35 at each later auszustanzenden film section 25 and that at the point on the film section 25, which later in the finished tear-open lid 28, the bent back flap 29 of this film section comes to rest. The punching of the individual film sections 25 in the sealing station can be controlled by printing marks on the belt, for example. These print marks can also be used as aids when the adhesive surfaces 30 are correctly placed, if necessary. But it can also serve as an imprint on the Aufreissfolienabschnitten itself as a marker.

In the example shown, a double-sided adhesive tape 33 is passed transversely to the tear-open film belt 35 over this. This is a preferred example, but the adhesive tape could also be passed over the belt 35 obliquely or in the same direction. Instead of a band 33, several individual bands could be provided. The double-sided adhesive tape has on its the band 35 opposite bottom, which preferably has stronger adhesion than the top, no protective film. On the other hand, a protective film 37 is provided on the upper side, which in the FIG. 11 is visible in plan view. A suitable for applying to the tape 35 double-sided adhesive tape with correspondingly different bond strength on the two sides and with one-sided protective film on the less adhesive side, is for example the tape tesafix 6917 from tesa Bandfix AG, Bergdietikon, Switzerland. This adhesive tape is known to be used for the reversible closure of film bags. By a punching device ( FIG. 12 ), the adhesive tape running over the belt 35 is punched, so that the adhesive surfaces 30 are punched out of the adhesive tape 33. They are preferably applied by the punching tool directly to the belt 35, where they stick with their protective film-free underside. The top of each adhesive surface is covered by the die-cut protective film 37. In band 33, the voids remain 33 '.

As in FIG. 11 at the Aufreissdeckeln 28, visible in the conveying direction C directly after the band 35 are, as shown in each case a lid 28 is formed with a tear-open film 25, from which a tab 29 projects beyond the edge of the lid and in which on the lid, a splice 30 is provided, which is still covered with a protective film 37. The protective film 37 allows the trouble-free sealing of the tear-open film 25 on the cover ring and protects the adhesive surface 30th

Thereafter, the protective film 37 is removed and the tab 29 is bent back onto the free adhesive surface 30, where it is fixed by the adhesive, resulting in the in the FIGS. 9 and 10 shown cover 28 leads. In the example of FIG. 11 In this case, in the station 40, the removal of the protective film 37 and in the station 41, the bending back of the tab 29. In between the lid is rotated in a defined position for the bending back, but this can also be done before. At the end of the conveyor line of FIG. 11 then the lid 28 is visible with glued-back tab. The bending back of the tab is already known in the art and will not be explained here. On the other hand, the punching of the splices and the removal of the protective film 37 will be discussed in more detail below.

FIG. 12 shows the punching of the subsequent bonding surfaces 30 forming pieces of double-sided adhesive tape 33. This is withdrawn from a roll 34 and passed over the belt 35, which in FIG. 12 can be seen cut from the plane of the drawing. In the area of the four driven punches 38, the belt 35 runs over a support surface 36, so that the punches can press the punched piece of adhesive tape onto the belt 35. The construction of driven punching tools 38 for the adhesive tape 33 is a professional measure. On its surface, the band 33 is not adhesive through the protective film 37, so that the punch of each punching tool does not need to be protected against sticking to the adhesive tape. The underside of the adhesive tape is adhesive, so that the die and the adjacent areas of the punch with a non-stick coating, such as a Teflon coating must be provided so that the tape does not adhere to the die or its environment during the punching.

Based on FIGS. 13 and 14 the removal of the protective film 37 from the adhesive surface 30 is explained. In this case, on the one hand with an air jet 43 obliquely blown from the side of the adhesive surface 30, which raises the protective film and dissolves. On the other hand, a suction flow 46 is generated and thus air is sucked off over the adhesive surface, which promotes the dissolved protective film 37. The FIGS. 13 and 14 show a partially sectioned view of a station 41 without the conveyor or the holding means for the cover 28. Preferably indicated via an annular nozzle 44 with arrows 43 indicated compressed air around obliquely on the edge of the adhesive surface 30. Preferably, the edge of the adhesive surface is enlarged relative to a round adhesive surface by the adhesive tape is punched star-shaped or gear-shaped. This promotes detachment of the protective film 37 from the adhesive tape when blowing laterally onto the adhesive surface. A suction opening 45 centrally above the adhesive surface 30 can aspirate the detached protective film 37 by means of a suction flow 46 generated by negative pressure. In addition to releasing the protective film 37 by air, a mechanical release by grippers or fingers can be provided, which lift the protective film at least at the edge of the adhesive surface.

In the production of tear-open lids 28 from cover rings 20 'with tear-open foil 25 having a tear-open tab 29, the tear-open tab is thus fixed by an adhesive surface 30, which is applied to the band from a band 35 of this material before the tear-off foil 25 is punched out. In this way results in a simple and suitable for the production of tear-open at high speed tab fixation.

Claims (9)

1. Method for producing peel-off lids (28), comprising the steps

   - feeding a web (35) of peel off foil material;

   - punching a foil section (25) with a peel-off tab (29) out of the web (35);

   - sealing the foil section (25) onto a lid ring (20');

   - folding back the peel-off tab (29) onto the lid (28);

   - applying an adhesive surface (30) onto the web (35) before punching out the foil section (25), at a position at the peel-off lid (28) where the folded back peel-off tab (29) lies, characterized in that the adhesive surface (30) is applied as a piece of a double-sided adhesive tape (33), wherein the adhesive tape has a protective foil (37) at its upper side, which is removed before folding back the peel-off tab (29).
2. Method according to claim 1, characterized in that an adhesive tape (33) is applied, having differently strong adhesive forces on its both sides, wherein the adhesive force on the side facing the peel-off tab (29) is smaller.
3. Method according to claim 1 or 2, characterized in that the piece above the web (35) is punched out of the adhesive tape (33) and is applied onto the web (35) directly after that.
4. Method according to one of the claims 1 to 3, characterized in that the protective foil (37) is loosened with at least an air jet (43), and in that the loosened protective foil (37) is sucked off by means of a suction flow (46).
5. Method according to claim 1, characterized in that the adhesive surface is applied as a liquid.
6. Method according to claim 5, characterized in that a sealing paint is applied as adhesive surface, particularly by pressing or spraying, and in that a sealing for fixing the tab is done during folding the tab (29) back onto the lid.
7. Device for producing peel-off lids (28), comprising a conveying system for lid parts and lids (20, 20', 28), a sealing station (5, 6) inside which a web (35) of peel-off foil material can be supplied by supply means (36), wherein the sealing station is adapted to punch a foil section (25) with a peel-off tab (29) out of the web (35) and to seal the foil section (25) with its sealable underside onto a lid ring (20'), as well as a folding station (42) inside which the peel-off tab (29) can be folded back onto the lid, wherein a system (38, 39) is provided, by means of which an adhesive surface (30) can be applied on the upper side (26) of the web (35) before punching out the foil section (25), characterized in that a system (41) for removing a protective foil (37) from the adhesive surface is provided.
8. Device according to claim 7, characterized in that the system has at least an input for at least an adhesive tape (33) as well as at least a punching tool (38) by means of which the adhesive surface (30) can be punched out of the adhesive tape (33) and applied on the upper side (26) of the web (35).
9. Device according to claim 7 or 8, characterized in that the system is adapted to act upon the adhesive surface by means of compressed air (43) and to suck off the loosened protective foil.

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