EP1993922B1 - Shrink-film seal and method for sealing containers - Google Patents

Abstract

A shrink-film seal (101, 201, 301, 401) is described having at least one stamped portion (102, 402, 602, 702) which is arranged along the circumference of a container (203, 303) which is to be sealed. The regions which are defined by the stamping lines are designed in such a way that at least one contiguous window is produced by a shrinking process. This achieves a situation where the opening of the sealed container can be immediately detected simply, without aids or expert knowledge and therefore a considerable increase in the product security is ensured. A method is also described for sealing containers with a shrink-film seal (101, 201, 301, 401).

Description

The present invention relates to a film seal in the form of a shrink film. Furthermore, it relates to a method for sealing containers with such a film seal.

Shrink wrap sleeves - also called shrink sleeves - are used in a variety of applications. For example, they serve the decoration of containers such as glass or plastic vials or the joining of several containers into a single unit, such as in beverage bottles. A third possible function of shrink-wrapped films is that of the sealing of containers. A foil seal is then spoken of when a so-called first-hole detection is performed, which discloses when the container has been opened. Shrinkable film seals therefore cover the point at which a container is usually opened, for example, the transition between the container and its cap.

Shrinkage is the process of expansion reduction of a film to understand, with the aim of applying a shrink tube tight and usually under tension fitting to a container. This may on the one hand (cold shrinkage) is a process in which a film is first stretched by an appropriate tool and pulled over the corresponding container and then resets the elastic strain and the film adapts to the outline of the container. On the other hand (in the case of the heat-shrinking process) a film can be used which contracts strongly under the action of higher temperatures. By heating a loose applied over a container shrink film, this also hugs according to the outline of the container. In addition to these two proven shrinkage process, however, other approaches are possible, such as shrinkage, initiated by chemical action or otherwise physically induced shrinkage, for example due to exposure to radiation. The type of shrinkage also depends on the shape of the shrink-wrapped film casing in which it is supplied: For the cold shrink method, tubular shrink-wrapped film casings are inevitably used; In the case of the heat-shrinking process, it is also possible to provide the film in a flat, non-tubular form. The film is then partially glued to the container with the aid of pressure-sensitive adhesives or activatable adhesives and wound around it, usually in such a way that the second end of the Film again comes to rest on the film surface in the region of the first end of the film and is fixed there again with the help of adhesives. The shrinkage then takes place in the aftermath of the dispensing of the film. The term shrink film seal in the following both described forms of film seals, so both tubular and flat, understood.

• Erstens muss das Schrumpf-Foliensiegel so auf dem Behältnis aufgebracht sein, dass eine Öffnung des Behältnisses ohne Zerstörung des Foliensiegels nicht möglich ist. Dies wird üblicherweise dadurch gewährleistet, dass das Foliensiegel beidseitig über die Ränder oder über Verjüngungen des Behälters so stark geschrumpft wird, dass beispielsweise eine Behälterkappe nicht ohne Beschädigung herausgezogen werden kann.
• Zweitens muß der Erstöffnungsnachweis irreversibel sein, um ein unerkanntes Wiederverschließen unmöglich zu machen.

In order to credibly indicate that a container provided with a shrink-foil seal has not yet been opened, essentially three aspects must be ensured:

• First, the shrink-film seal must be applied to the container so that an opening of the container without destroying the film seal is not possible. This is usually ensured by the fact that the film seal is shrunk so much on both sides over the edges or over the taper of the container that, for example, a container cap can not be pulled out without damage.
• Second, the first-hole detection must be irreversible in order to prevent an unrecognized re-closure.

Third, finally, the destruction of the foil seal must be clearly visible.

For this purpose, the prior art offers three technical solutions: In a first simple variant, films are selected for shrink-film seals in such a way that they break when an opening of the container takes place. In the second variant, a defined tearing is achieved by weakening at a predetermined breaking point, usually by a perforation. The third and most special variant is the equipment of the film with a tear thread.

The use of tearing threads, however, is on the one hand cost-intensive and on the other hand arouses associations with the consumer goods industry, which is not desired by the user, especially in security-relevant or pharmaceutical fields of application. Similar, above all aesthetic, reservations also prevail in the first variant of a self-tearing film. Perforations, on the other hand, are simple and effective to manufacture, but have the distinct disadvantage that an opening can often be recognized too late by the naked eye: a straight tearing along a line is usually difficult for the inexperienced user to make out.

The publication DE 197 50 429 A1 relates to a method of applying a perforated sleeve of sheet-like foam provided with holes or cuts to a container. In the publication JP 06-270965 A For example, a shrink-wrap package is provided which can easily tear the shrink-wrap film even if it has already been applied to an article. The publication EP 1 116 667 A1 indicates a container whose surface and in particular its opening is surrounded by a shrinkable label. In the publication FR 2 222 278 is a container on which a shrink film is applied with punched openings or punched lines indicated.

The present invention is therefore an object of the invention to provide a shrink-film seal with tear region, in which the opening of the sealed container is easy to recognize immediately without tools or expertise and thus a significant increase in product safety is guaranteed. In addition, it is an object of the invention to develop a method that enables its users to produce appropriate shrink-film seal and thus seal a container so that the opening of the sealed container is easy to identify immediately without tools or expertise. Another object is to provide a corresponding container.

The object is achieved according to the present invention by means of a shrink-film seal according to claim 1, wherein by the shrinking on a designated container in the region of the punches a window area is created. Furthermore, the object is achieved by a method according to claim 13, which envisages shrinking a shrink-film seal on a container so that form windows in the region of the punches of the film seal. The provision of a corresponding container is achieved by a container according to claim 23. Preferred embodiments of the invention are claimed in the dependent claims 2-12, 14-22 and 24-27.

• Fig. 1 ein erfindungsgemäßes Schrumpf-Foliensiegel in der Draufsicht,
• Fig. 2 ein erfindungsgemäßes Schrumpf-Foliensiegel in appliziertem Zustand auf einem zylindrischen Behältnis.
• Fig. 3 ein erfindungsgemäßes aufgerissenes Schrumpf-Foliensiegel in appliziertem Zustand auf einem zylindrischen Behältnis.
• Fig. 4 eine besonders bevorzugte Ausführungsform der Schlitzung eines erfindungsgemäßen Schrumpf-Foliensiegels
• Fig. 5a-g verschiedene Stanzungsformen für den Aufreißbereich erfindungsgemäßer Schrumpf-Foliensiegel
• Fig. 6a und b eine besonders bevorzugte Stanzungsform vor und nach dem Schrumpfen
• Fig. 7a und b eine weitere besonders bevorzugte Stanzungsform vor und nach dem Schrumpfen
• Fig. 8 ein Schrumpf-Foliensiegel gemäß Stand der Technik in der Draufsicht,
• Fig. 9 ein Schrumpf-Foliensiegel gemäß Stand der Technik in appliziertem Zustand auf einem zylindrischen Behältnis.

In the following the invention is based on the Figures 1-9 described in more detail, all drawings are to be understood schematically and especially the layer thicknesses for the sake of clarity are shown greatly enlarged. They show:

• Fig. 1 an inventive shrink-film seal in plan view,
• Fig. 2 an inventive shrink-film seal in the applied state on a cylindrical container.
• Fig. 3 an inventive torn shrink-film seal in the applied state on a cylindrical container.
• Fig. 4 a particularly preferred embodiment of the slit of a shrink-foil seal according to the invention
• Fig. 5a-g various punching forms for the tear region of inventive shrinkable film seal
• Fig. 6a and b a particularly preferred die before and after shrinking
• Fig. 7a and b Another particularly preferred punching form before and after shrinking
• Fig. 8 a shrink-film seal according to the prior art in plan view,
• Fig. 9 a shrink-film seal according to the prior art in the applied state on a cylindrical container.

FIG. 8 shows a shrink-film seal 801 according to the prior art, formed from a tubular film and provided with an opening perforation 802nd

In FIG. 9 is the - numbered analog - shrink-film seal 901 shrunk onto a container 903. Over a Übergarigsbereich Ü between the container 903 and the container cap 904 (the outlines are indicated by dashed lines in the areas that covers the shrink-foil foil) comes the opening perforation 902 to lie. It can be seen that the upper cap portion is also partially covered by the shrink-film seal 901 - a result of the shrinkage process.

If the container 903 is now opened by removing the container cap 904, the shrink-foil seal 901 ruptures along the opening perforation 902. However, this opening detection is barely visible to the naked eye, so that uninitiated can easily assume that the container is still unopened.

In contrast, the in FIG. 1 illustrated shrink-film seal 101 according to the invention on a special punching 102, here in the form of an inverted T. At least two punching lines meet and there are at least two corners, preferably at an angle between 60 and 120 degrees.

The effect of this special punching is in FIG. 2 illustrates: A container 203 with a container cap 204 is analogous to FIG. 9 an inventive shrink-film seal 201 of the same kind as in FIG. 1 shrunk down. Due to the shrinking process, especially due to the heat shrinkage, windows 205 are now produced in the area of the punched holes. This phenomenon is explained by the fact that the foil in the area of the punching is not under tension like the remaining area of the shrinkable foil seal and therefore inwardly in the direction of the container shrinks away. For the user, this type of opening area is clearly visible from the outset. This effect is exacerbated when the film seal has a whole or partial area of a color that matches the Container 203 contrasts. Furthermore, the effect is particularly effective when there is a free zone, for example a recess in the container 203 or in the transition region between the container 203 and the container cap 204 below the punching. This makes it possible that the film, where it is freely movable in the region of the punching without tension, both shrink in itself and can fold backwards into the open zone. Particular preference is therefore given to films having a high shrinkage tendency, the reduction in length during shrinkage being more than 40%, preferably more than 60%. The material used for hot shrink films here primarily polyethylene terephthalate (PET), polyvinyl chloride (PVC) oriented polystyrene (OPS) and polypropylene (PP) in question; Polyethylene films are especially suitable for cold shrink processes). In order to enable optimum shrinking, it is advantageous to use films or film composites with a thickness of between 30 and 100 μm, more preferably between 50 and 75 μm.

In FIG. 3 a corresponding container 303 is shown with an open shrink-film seal 301. In the area of the bridges between the windows FIG. 2 now cracks 306 are visible, which inevitably arise during the opening process. An unrecognized accurate joining of the edges of these cracks is not possible: The torn-off webs between the windows formed from the special punches are due to the stresses that occur and are also tactile felt immediately. In addition, they are irregular in shape (indicated here by serrations), since in the course of shrinking by the stresses occurring a slight tearing of the punching lines.

A particularly preferred embodiment of the special punches can be found in FIG. 4 : Here the punches are offset in height, giving an even more obvious tearing-proof.

Further possible embodiments of special punchings according to the invention for shrink-foil seal are in the FIGS. 5a-d recognizable while in Figures 5e-g different arrangements of punch geometries are exemplified. Common to all embodiments and arrangements is the formation of at least two corners by punching lines. A corner is created when two lines meet and are at an angle that is not 180 degrees. In the case of a T-punching, for example, two corners already result from this, that one line continues beyond the meeting point of the two lines. For illustration, in the FIGS. 5a-d the number of corners is numbered with Roman numerals. Basically, the corners do not have to be sharp, but the definition also includes rounded shapes that open into a straight line on both sides.

Due to the special die-cut form, it is ensured that when shrinking, a clearly recognizable window area is formed, which would not be possible with a line punching or with punching with just one corner or other geometric shapes. This effect is in FIGS. 6a / b and 7a / b.

Fig. 6a shows two adjacent punched holes 602 in T-shape, a particularly preferred embodiment of the punching. In Fig. 6b the situation is shown after shrinking the shrink-foil label onto a container: two adjacent windows (recognizable by the horizontal hatching) in the form of isosceles triangles were formed. Between them is a web 608, which should tear when opening the container.

Analog numbered and hatched is in Fig. 7a and b Another particularly preferred punching geometry, here in the form of an inverted H, shown. On the basis of the two pairs of figures 6a / b and 7a / b it is clear that by selecting the correct punching geometry a variety of different window shapes can be formed by shrinking.

In addition to the features outlined here, it is possible to provide the inventive shrinkable film seals with a number of additional functions, such as those used in the security film sector and in the label industry: In the first place not only dyeings but also printing with lettering, symbols and similar decorative elements can take place , Furthermore, additional security elements such as (visible and invisible) security printing methods, holograms, color effects, metal strips or the like can be used. Non-shrinkable film parts on or under the seal label may be used for stabilization, as well as additional pharmaceutical-grade label components, for example, self-adhesive removable adhesive labels, information booklets or infusion steel suspending devices.

Claims (25)

1. A shrink-film seal (101, 201, 301, 401) having at least one punching (102, 402, 602, 702) disposed along the circumference of a container (203, 303) to be sealed, characterized in that at least one punching (102, 402, 602, 702) has at least two corners, and the regions defined by the punched lines are configured in such a manner that at least one contiguous window (205) is brought about by means of a shrinking process.
2. The shrink-film seal (101, 201, 301, 401) as claimed in claim 1, characterized in that the punching (102, 402, 602, 702) has the shape of a T or the shape of an H.
3. The shrink-film seal (101, 201, 301, 401) as claimed in any of claims 1 or 2, characterized in that the angles lie at an angle between 60 and 120 degrees.
4. The shrink-film seal (101, 201, 301, 401) as claimed in any of the preceding claims, characterized in that multiple punchings (102, 402, 602, 702) lie in different planes, offset relative to one another.
5. The shrink-film seal (101, 201, 301, 401) as claimed in any of the preceding claims, characterized in that it is heat-shrinkable.
6. The shrink-film seal (101, 201, 301, 401) as claimed in any of the preceding claims, characterized in that it is cold-shrinkable.
7. The shrink-film seal (101, 201, 301, 401) as claimed in any of the preceding claims, characterized in that it consists of a material whose length reduction potential while shrinking amounts to more than 40%.
8. The shrink-film seal (101, 201, 301, 401) as claimed in any of the preceding claims, characterized in that it contrasts with the intended background in terms of its coloring.
9. The shrink-film seal (101, 201, 301, 401) as claimed in any of the preceding claims, characterized in that the punchings (102, 402, 602, 702) are disposed at regular intervals.
10. The shrink-film seal (101, 201, 301, 401) as claimed in any of the preceding claims, characterized in that the regions defined by the punched lines (102, 402, 602, 702) are configured in such a manner that at least one crosspiece (608, 708) is formed between the windows (205) by means of the shrinking process.
11. The shrink-film seal (101, 201, 301, 401) as claimed in any of the preceding claims, characterized in that the film consists of a material that can be shrunk onto a container (203, 303) under tension.
12. A method for sealing containers (203, 303) with a shrink-film seal (101, 201, 301, 401), comprising the following steps:

    a) providing a shrink-film seal as claimed in any of claims 1 to 11,

    b) shrinking the film seal (101, 201, 301, 401) onto a container (203, 303) in such a manner that at least one window (205) is formed in the region of the punchings (102, 402, 602, 702) of the film seal.
13. The method as claimed in claim 12, characterized in that the shrinking process is a physically induced process.
14. The method as claimed in claim 13, characterized in that the shrinking process is a heat-shrinking process or a process induced by means of radiation.
15. The method as claimed in claim 12, characterized in that the shrinking process is a cold-shrinking process.
16. The method as claimed in claim 12, characterized in that the shrinking process is a chemically induced process.
17. The method as claimed in any of claims 12 to 16, characterized in that the shrinking brings about a length reduction of at least 40%.
18. The method as claimed in any of claims 12 to 17, characterized in that, prior to the shrinking, the region of the punching (102, 402, 602, 702) is brought to lie on a transition region between the container (203, 303) and a container cover (204, 304).
19. The method as claimed in any of claims 12 to 18, characterized in that, prior to the shrinking, the region of the punching (102, 402, 602, 702) is brought to lie on a depression of the container, brought about by a decrease in circumference of the container (203, 303) in this region.
20. The method as claimed in any of claims 12 to 19, characterized in that the shrinking takes place in such a manner that the shrink-film seal (101, 201, 301, 401) is put under tension so that the cross-pieces (608, 708) between the windows (205) clearly protrude after the seal is opened.
21. The method as claimed in any of claims 12 to 20, characterized in that for this purpose, a shrink-film seal (101, 201, 301, 401) as claimed in any of claims 1 to 11 is used.
22. A container having a shrink-film seal (101, 201, 301, 401) as claimed in any of claims 1 to 11 shrunk onto it, characterized in that the unopened state of the container (203, 303) is indicated by the integrity of windows (203) of the shrink-film seal.
23. The container (203, 303) as claimed in claim 22, characterized in that a material tension is present in the film which causes the cross-pieces (608, 708) between the windows (205) to clearly protrude after the shrink-film seal (101, 201, 301, 401) has been opened.
24. The container (203, 303) as claimed in any of claims 22 or 23, characterized in that the color of the shrink-film seal (101, 201, 301, 401) contrasts with that of the container (203, 303) at least in partial regions.
25. The container (203, 303) as claimed in any of claims 22 to 24, characterized in that the region of the windows (205) lies in a transition region between the container and a container cover (204, 304) and/or on a depression of the container brought about by a decrease in circumference of the container (203, 303) in this region.

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