Patent Application
20170233157
The present invention relates to a film packaging. More particularly this invention concerns a film bag and method of using same.
A typical film packaging bag has a front panel extending in longitudinal and transverse directions and a normally identical rear panel also extending parallel to the front panel in the longitudinal and transverse directions. The two panels are secured together to form an internal space adapted to hold something being packaged. To this end the front panel and rear panel are interconnected by a transversely extending weld that closes a lower end edge of the film packaging. The front and/or rear panel may project longitudinally from a side of the transverse weld facing away from the packaging interior.
A film packaging of this generic type can be manufactured and simultaneously filled with particular ease using a so-called “Form Fill and Seal” (FFS) method. In that method, a film web is fed to form a front panel extending in the longitudinal and transverse directions and to form a rear panel extending in the longitudinal and transverse directions, to form the interior space between the front and rear panels. The product is placed into the interior space between the front and rear panels, and the interior space is subsequently sealed at least by a transverse weld that interconnects the front and rear panels and extends transversely at an upper edge.
Such methods are used industrially in automatic packaging lines in order to provide any product with easy-to-handle outer packaging made of film. The method is also suitable for any type of product. For instance, block- or bar-shaped products are particularly well suited for such a packaging method. However, bulk products such as pellets, powder, and even liquids can also be processed using an FFS process if it is carried out vertically as a so-called VFFS (Vertical Form Fill Seal) process. The film packaging is first prefabricated such that it is tightly sealed on the longigudinally extending side edges and lower edge, thus enabling the bulk product to be filled from above. The film packaging is then sealed across the top of the interior space by an upper-edge transverse weld.
In order to meet the high mechanical demands of transport and bag-forming, a high-strength film web is preferably used in the FFS method. Preferably, oriented or biaxially oriented polymer films such as OPET (Oriented Polyethylene Terephthalate) or BOPP (Biaxially Oriented Polypropylene) are used. Cellulose-based film layers are also especially well suited for use in this regard.
However, these materials have the drawback that they have unpredictable tearing characteristics. While layers made of the above materials tear easily, the tear propagation is then random to a great degree. In multilayered film composites with other functional layers as well, such as sealing or covering layers, for example, the tearing characteristics are determined almost exclusively by the brittle layer. It is for this reason that film packaging manufactured using the FFS method can be opened by the user by tearing only to a very limited extent. Rather, it is generally more expedient to open the film packaging by opening at least one weld. This is known in the area of snack packaging, for example.
Nonetheless, it is desirable to make a defined tear-open behavior available in modern FFS packaging as well. This can be necessary in order to reproducibly create an opening of sufficient size for bar-shaped products, for instance. In this way, the product can be removed in its entirety, for example. In the case of bulk products as well, a defined opening is essential in order to prevent uncontrolled spilling. At the same time, however, easy manufacturability should be maintained.
It is therefore an object of the present invention to provide an improved film packaging and method of using same.
Another object is the provision of such an improved film packaging and method of using same that overcomes the above-given disadvantages, namely that is easy to open regardless of the type of film it is made from.
A packaging has according to the invention juxtaposed front and rear panels having juxtaposed upper and lower end edges and juxtaposed side edges extending between ends of the end edges. The side edges are fastened together to define an interior space between the panels, a plurality of longitudinally extending weakened tear lines formed in and extending along a full longitudinal length of each of the panels, and respective upper and lower transversely extending welds extending along and securing together the upper and lower edges of the panels to longitudinally close the interior space.
The front and rear panels preferably have at least one plastic layer with an oriented polymer, particularly OPET or BOPP. According to the invention, reliable and reproducible tear-open behavior can be ensured even in film packaging with a film web that tends to tear uncontrollably, such as OPET or BOPP, for example. The transverse weld forming an end edge can be torn open easily and at a defined point, after which a tear is guided along two adjacent weakened tear lines. The “weld” can be either formed by melting together two thermoplastics, or bonding them with an adhesive.
Weakened tear lines are linear and/or stripe-line regions of the film web whose mechanical strength is reduced. Using a line of weakening, the tear propagation within a film web can be controlled, since tears tend to propagate into the regions having the lowest mechanical strength. A line of weakening can be produced particularly by reducing the material thickness and/or local changes in the material characteristics, as can be done during the manufacture of the film web or even subsequently. In particular, weakened tear lines can be formed so as to be continuous or interrupted in some portions. In terms of the invention, a line of weakening that is interrupted in some portions can also be a perforation having a uniformly repeating pattern over its entire extension longitudinally.
The at least two respective weakened tear lines are advantageously provided on the same outer surface of the front panel and/or rear panel. Preferably, they have the same depth of penetration into the material of the front panel and/or rear panel and, in the case of a multilayered construction, extend in the same sublayers. The at least two weakened tear lines are especially preferably identical.
As a result of the fact that a plurality of weakened tear lines are provided according to the invention on both the front and on the rear panel, an especially advantageous opening of the film packaging is made possible. The film packaging is divided as it is torn open between the two weakened tear lines along the longitudinal direction. When opened partially starting from the top side, for instance, a bar-shaped product can project only partially out of the opening and thus be consumed mouthful by mouthful. A food bar can be eaten like a partially peeled banana, for example. Alternatively, after the complete detachment of one half of the bag packaging, the entire product can be removed transversely.
This is advantageous particularly if the film packaging has a larger extension longitudinally than transversely. A special advantage can be achieved if the longitudinal extension is greater than 1.5 times, particularly greater than twice the transverse extension, since then even small deviations during the tear propagation can prevent the film packaging from being opened clean in a lengthwise manner.
Through the parallel arrangement of at least two weakened tear lines running longitudinally on the front and rear panel, an approximately linear tearing behavior can be ensured in the film packaging according to the invention despite a stiff film component. At the same time, the danger of the packing being torn open along the weakened tear lines during the packaging process is minimal, since the film web is subjected primarily to tensile stress and is stabilized by joining tools running transversely to produce the transverse weld. Shearing forces or bending moments perpendicular to the front or rear panel that might result in the initiation of a tear hardly ever occur. This is all the more true if the longitudinal direction of the front and rear panels are identical with a machine direction in which the film web is transported during the packaging process.
The transverse weld preferably extends over the entire width of the front panel and rear panel. A tight closure can thus be achieved on this end edge without additional aids. Moreover, the film packaging is stabilized over its entire width by the transverse weld. Depending on the area of application, the transverse weld can be produced by hot- or cold-sealing. An adhesive joint is also possible in the context of the invention.
A tear aid is especially preferably provided on the transverse weld. This can facilitate the starting of a tear into the transverse weld. For example, the tear aid can be embodied as at least one notch or a zigzag-shaped cut edge. It can extend over the entire width of the transverse weld or be limited to regions in which the tear is to be preferably initiated. In particular, the tear aid is provided only in the region between the weakened tear lines and not in edge regions between the lateral outside edges of the film packaging and the nearest line of weakening.
Especially preferably, the weakened tear lines are parallel to one another. This enables a corridor of constant width to be made available for the tear propagation.
It is especially preferred to provide at least three weakened tear lines equidistantly transversely on the front and/or rear panel. This enlarges the area within which the user can choose a position from which to initiate the tear. Nevertheless, once a tear is initiated in the channel formed by the two nearest weakened tear lines, it is propagated in nearly linear fashion to the opposing end edge of the film packaging.
The weakened tear lines are preferably distributed transversely over the entire width of the front panel and/or the rear panel. This gives the user a high degree of freedom in terms of the area in which he would like to tear open the packaging.
In another preferred embodiment, the weakened tear lines are limited to an area transversely. The user can thus be encouraged to tear open the film packaging in the designated area. This can be additionally supported by an appropriately positioned tear aid and/or a visual designation of the area. This merits consideration particularly if it is advantageous for the product to be touched directly only in certain areas. Depending on the requirement, the area in which the weakened tear lines are provided is around the middle. It can also be advantageous to provide the weakened tear lines in the middle or outer thirds of the film packaging.
Preferably, at least the outer weakened tear lines closest to a lateral edge of the packaging are parallel to the longitudinal direction. As a result, the tear propagation takes place in all cases such that the longitudinal side edges of the bag are not breached. This enables a complete division of the film packaging.
It is especially preferred if each line of weakening on the front panel is aligned so as to be congruent to or aligned with a line of weakening on the rear panel. This results in the same basic conditions being present on the front panel as on the rear panel during tearing.
In a preferred embodiment, the front and rear panels are formed from a single web of film. This web can be provided continuously with weakened tear lines over its entire width. The web can be advantageously closed by a so-called fin seal in which a portion of the inside of the film portion is joined together with another portion of the inside of the film portion, or an area of overlap in the case of a film tube.
Preferably, the front panel is connected to the rear panel on at least one side edge by a side fold. The side fold can be formed in the same film web as the front panel and/or rear panel or from a separate piece of film. A side fold enables the interior of the bag to be enlarged and the stackability improved. Preferably, one side fold is embodied without weakened tear lines in order to limit the tear propagation to the front and rear panel. Alternatively or in addition, the film packaging can be provided with a stand-up base on the side opposite the transverse weld.
One preferred film web for forming film packaging according to the invention is a multilayer laminate with an outer layer of BOPP having a thickness of 20 μm and an inner layer of metallized, biaxially oriented polypropylene (metBOPP) also having a thickness of 20 μm connected to the outer layer by a laminating adhesive layer. The metallized polymer acts as a barrier against penetration by water vapor and oxygen. The outer layer can be provided with an imprint on the inner face toward the inner layer. The outer layer is substantially transparent, so that the imprint is visible from the outside but is protected from damage by the outer layer. If the film packaging is to be sealed using a cold-sealing process, a layer of cold-seal adhesive can be additionally applied to the inside of the inner layer.
The invention is based on a method for packaging a product in a film packaging in which a film web is fed to form a front panel extending in the longitudinal and transverse directions and to form a rear panel extending in the longitudinal and transverse directions, so that an interior space is formed between the front and rear panels. The product is held in this interior space of the packaging between the front and rear panels. Subsequently, the interior space is sealed by at least one transverse weld connecting the front panel to the rear panel and extending transversely. According to the invention, at least two weakened tear lines running longitudinally are provided on the front panel and on the rear panel, respectively, and extend over the entire length of the front panel and of the entire rear panel longitudinally. The method is particularly suitable for providing a film packaging according to the invention.
In a preferred embodiment, the film web for the front and rear panels is fed endlessly. After packaging, the web with the product contained therein is cut to length after or during the formation of the transverse weld. Here, the film web is cut through in the area of the transverse weld, so that a single wide transverse weld is converted into an upper end-edge weld and a lower end-edge weld. Alternatively, it is also possible for the film web to be cut through only in areas, particularly in the form of a perforation. In this way, a predetermined breaking point is created that can be opened subsequently by the user or a machine.
It is advantageous for all or part of the dividing line to run through the weld. This leaves a seal on both sides in which the front panel and rear panel are interconnected. As a result, a portion of the transverse weld that closes off the interior of the bag of the film packaging can act simultaneously as a bottom weld for delimiting a film bag produced subsequently in a continuous process. At the same time, the weld forms the closure of the film packaging longitudinally, so that the front and rear panels cannot be separated from one another and can be torn open together.
Furthermore, it is advantageous to provide the film packaging with a tear aid on an end edge. This can be embodied as a zigzag cut, for example. Especially preferably, this can be done at the same time as the continuously manufactured film packaging is cut to length. Preferably, the tear aids are provided such that they can become operative between the weakened tear lines running longitudinally. This facilitates the initiation of a tear between at least two weakened tear lines, so that the tear cannot then wander in an uncontrolled manner to a side edge of the film packaging.
Preferably, the film web for the front panel and/or the rear panel with prefabricated weakened tear lines is fed in as a semifinished product. As a result, the packaging installation as a whole can have a more compact design, since the film web need not first be manufactured and/or finished. A prefabricated multilayered laminate in which the weakened tear lines are embodied on interior layers and/or interior boundary surfaces of layers can also be used with particular ease as a film web. This gives the film laminate a uniform, higher-quality outward appearance. What is more, if the longitudinal direction coincides with the machine direction, the feeding device can also have a simple design, since the front and rear panels need not be provided in a certain position in relation to one another.
In another preferred embodiment, the weakened tear lines are introduced into the front panel and/or rear panel before filling of the product. Laser cutting, die-cutting, mechanical removal of material (so-called scraping), or mechanical imprinting are particularly suitable for this purpose. Here, too, it is advantageous if the longitudinal direction coincides with the machine or web-feed direction, since the weakened tear lines can then be formed continuously and without synchronization.
Advantageously, a film tube is formed before the filling of the product from a single material web that constitutes the front and rear panels. The film tube can be sealed by a so-called fin seal or by a lap joint.
The above and other objects, features, and advantages will become more readily apparent from the following description, reference being made to the accompanying drawing in which:
As seen in
In this embodiment, the transverse welds 6 run both on the upper edge and on the lower edge over the entire width of the front and rear panels 2 and 3 in the transverse direction q. A tear aid 15 is provided on the end edges 5 in the form of a zigzag-shaped cut extending both into the transverse welds 6 and over the entire width of the film packaging 1 in the transverse direction q. The weakened tear lines 7 are provided parallel to one another and to the longitudinal direction 1 of the film packaging 1 and are distributed equidistantly over the entire width of the film packaging 1 in the transverse direction q between the outer edges 4.
No synchronization between the movement of the material web 8 and the sealing station 12 is necessary, since the weakened tear lines 7 extend in the feed direction FD in any case. Moreover, it is possible to manufacture film packagings 1 of different sizes from the same film web 8 by varying the timing of closing and operation of the sealing station 12 in relation to the speed at which the film web 8 is fed.
In another variant according to
| Number | Date | Country | Kind |
|---|---|---|---|
| 102016102691.3 | Feb 2016 | DE | national |
