Sealing membrane with pull-tab

Abstract

The invention concerns a sealing membrane (2) for a container (5), said membrane (2) having an edge region (4) intended to be secured around an opening (5a) of the container (5) such as to form a sealing of the container (5), the membrane (2) comprising a pull-tab (1) extending from a portion of the edge region (4) such as to facilitate simplified release of the membrane (2). The invention is characterized in 12 that the pull-tab (1) comprises a stiffening structure (7) arranged in a pattern that defines an intended folding line (3) extending across the pull-tab (1). The invention also concerns a container arrangement (8) comprising a container (5) with an opening (5a) and, at least partly secured to the container (5) around the opening (5a), a sealing membrane (2) of the above type. The invention also concerns a method of manufacturing a sealing membrane (2) of the above type, wherein the method comprises the step of embossing, corrugation, creasing, folding and/or heat shaping the stiffening structure (7).

Claims

1. A sealing membrane for a container, said membrane comprising: an edge region intended to be secured around an opening of the container to form a sealing of the container; and a pull-tab extending from a portion of the edge region to facilitate simplified release of the membrane, the pull-tab comprising a stiffening structure arranged in a pattern that defines an intended folding line extending across the pull-tab, the intended folding line is positioned in a zone extending from the portion of the edge region to a first end of the stiffening structure, the zone being free from stiffening structures from the portion of the edge region to the first end of the stiffening structure, wherein the stiffening structure comprises elevations and depressions formed in at least parts of the pull-tab and the stiffening structure comprises a plurality of elongated stiffening elements extending from the intended folding line towards an outer edge of the pull-tab, each stiffening element of the plurality of elongated stiffening elements having a first end and a second end and each of the plurality of elongated stiffening elements extending in a direction of extension that differs from each of the other stiffening elements of the plurality of elongated stiffening elements and the first end of each of the plurality of elongated stiffening elements extends towards the intended folding line and the second end of each of the plurality of elongated stiffening elements extends towards the outer edge of the pull-tab.

2. The sealing membrane according to claim 1, wherein the stiffening structure comprises embossed, corrugated, creased, folded or heat-shaped material.

3. The sealing membrane according to claim 1, wherein the intended folding line extends in a direction substantially parallel with the portion of the edge region.

4. The sealing membrane according to claim 1, wherein the plurality of elongated stiffening elements extends from a central region of the intended folding line towards the outer edge of the pull-tab.

5. The sealing membrane according to claim 1, wherein the plurality of elongated stiffening elements are substantially straight.

6. The sealing membrane according to claim 1, wherein the portion of the edge region from which the pull-tab extends is curved.

7. The sealing membrane according to claim 1, wherein the sealing membrane comprises a layer of aluminium.

8. The sealing membrane according to claim 1, wherein the sealing membrane comprises a layer of a plastic material.

9. The sealing membrane according to claim 8, wherein the layer of the plastic material comprises polyethylene or polypropene.

10. The sealing membrane according to claim 1, wherein the sealing membrane is a laminated layer structure comprising a layer of aluminium and a layer of a weldable plastic material.

11. A method of manufacturing a sealing membrane according to claim 1, wherein the method comprises the step of embossing, corrugation, creasing, folding and/or heat shaping the stiffening structure.

12. The sealing membrane according to claim 1, wherein the portion of the edge region from which the pull-tab extends forms part of a rounded corner of the sealing membrane.

13. The sealing membrane according to claim 1, wherein the pull-tab further comprises a hole formed in the pull-tab.

14. The sealing membrane according to claim 13, wherein the intended folding line extends through the hole.

15. A container arrangement comprising a container with an opening and, at least partly secured to the container around the opening, a sealing membrane, the sealing membrane comprising an edge region secured around the opening of the container to form a sealing of the container, the membrane comprising a pull-tab extending from a portion of the edge region to facilitate simplified release of the membrane, the pull-tab comprising a stiffening structure arranged in a pattern that defines an intended folding line extending across the pull-tab, the intended folding line is positioned in a zone extending from the portion of the edge region to a first end of the stiffening structure, the zone being free from stiffening structures from the portion of the edge region to the first end of the stiffening structure, wherein the stiffening structure comprises elevations and depressions formed in at least parts of the pull-tab and the stiffening structure comprises a plurality of elongated stiffening elements having a first end and a second end and each of the plurality of elongated stiffening elements extending from the intended folding line towards an outer edge of the pull-tab, each stiffening element of the plurality of elongated stiffening elements extending in a direction of extension that differs from each of the other stiffening elements of the plurality of elongated stiffening elements and the first end of each of the plurality of elongated stiffening elements extends towards the intended folding line and the second end of each of the plurality of elongated stiffening elements extends towards the outer edge of the pull-tab.

16. The container arrangement according to claim 15, wherein the edge region of the membrane is folded and secured to inner walls of the container.

17. A sealing membrane for a container, said membrane comprising: an edge region intended to be secured around an opening of the container to form a sealing of the container; and a pull-tab extending from a portion of the edge region to facilitate simplified release of the membrane, the pull-tab comprising a stiffening structure arranged in a pattern that defines an intended folding line extending across the pull-tab, the intended folding line is positioned in a zone extending from the portion of the edge region to a first end of the stiffening structure, wherein the stiffening structure comprises elevations and depressions formed in at least parts of the pull-tab and the stiffening structure comprises a plurality of elongated stiffening elements extending from a common point of origin on the intended folding line towards an outer edge of the pull-tab, each stiffening element of the plurality of elongated stiffening elements having a first end and a second end and each of the plurality of elongated stiffening elements extending in a direction of extension that differs from each of the other stiffening elements of the plurality of elongated stiffening elements and the first end of each of the plurality of elongated stiffening elements extends towards the intended folding line and the second end of each of the plurality of elongated stiffening elements extends towards the outer edge of the pull-tab.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The present invention will now be described in detail with reference to the figures, wherein:

(2) FIG. 1 shows, in an exploded view, a container, an outer lid and an embodiment of the inventive sealing membrane;

(3) FIG. 2 shows the parts of FIG. 1 in an assembled state;

(4) FIG. 3 shows the sealing membrane according to FIG. 1;

(5) FIG. 4 shows the sealing membrane according to FIG. 1 secured to the container with the pull-tab pointing upwards;

(6) FIG. 5 shows the sealing membrane according to FIG. 1 secured to the container and with the pull-tab folded towards the membrane;

(7) FIG. 6 shows an opened outer lid mounted onto the container according to FIG. 5.

DETAILED DESCRIPTION

(8) In the following only one embodiment of the invention is shown and described, simply by way of illustration of one mode of carrying out the invention.

(9) FIG. 1 shows, in an exploded view, a container arrangement 8 comprising a container 5 with an opening 5a, a sealing membrane 2 and an outer lid 9 comprising a lid frame 9a connected to a hinged openable lid 9b. As an example of known materials for such a container arrangement 8, the container 5 is a laminated structure comprising layers of cardboard, aluminium and a plastic weldable layer, the membrane 2 is also a laminated structure comprising layers of aluminium and a plastic weldable layer, and the outer lid 9 is made of a plastic material. Other materials are possible to use.

(10) After filling of the container 5 with e.g. a food product in powder form, the container 5 is sealed by securing the membrane 2 around the opening 5a by fastening an edge portion 4 of the membrane 2 to the inner walls of the container 5 (see FIGS. 4-6). The outer lid 9 is attached to the container 5 by known means by pressing the outer lid 9 onto an upper rim of the container 5 above the sealing membrane (see FIG. 6). FIG. 2 shows the container arrangement 8 in an assembled state.

(11) FIG. 3 shows in an enlarged view the sealing membrane 2 of FIG. 1. As can be seen in FIG. 3, the edge region 4 extends circumferentially around the sealing membrane 2. A pull-tab 1 for facilitating release of the membrane 2 extends from a portion of the edge region 4 located at a rounded corner of the membrane 2. The pull-tab 1 has a base, a top and two sides, wherein the base is connected to the sealing membrane 2.

(12) The pull-tab 1 further comprises a stiffening structure 7 arranged in a pattern that defines an intended folding line, indicated with the line 3, extending across the pull-tab 1.

(13) The stiffening structure 7 is made up of elongated stiffening elements in the form of elevations and depressions formed by, in this case, embossing. The intended folding line 3 extends in this case in a direction substantially parallel with the portion of the edge region 4 across the pull-tab 1 from side to side and through a punched hole 12. This hole 12 has the purpose of improving the inductive heat sealing process (it affects the current density) when securing the membrane to the container 5. The punched hole 12 is not necessary for the present invention but if present it is normally an advantage to direct the intended folding line 3 through the hole 12.

(14) The position of the intended folding line 3 is set by the pattern of the stiffening structure 7. FIG. 3 shows that the stiffening structure 7 comprises a plurality of elongated straight stiffening elements extending from a central region, in this case the hole 12, of the intended folding line 3 towards an outer edge of the pull-tab 1. In this example, the most central stiffening element is parallel to the main direction of extension of the pull-tab 1, i.e. it forms an extension of a diagonal of the membrane 2. This central stiffening element extends from the central region of the intended folding line 3 towards the outermost edge of the pull-tab 1.

(15) A number of additional elongated straight stiffening elements, in this case three on each side of the most central stiffening element, extend also from the central region of the intended folding line 3 towards the edge of the pull-tab 1. All stiffening elements have a unique extension direction, i.e. there are no parallel stiffening elements. The three stiffening elements on each side of the central stiffening element exhibits an angle of about 12, 25 and 50 degrees, respectively, to the central stiffening element. Thereby, the seven stiffening elements form the pattern of a fan. Folding is thereby prevented or at least made more difficult except along the intended folding line 3 across the pull-tab 1 through the central region of the folding line 3.

(16) As can be seen in the figures the stiffening elements merge close to the hole 12. In other embodiments the stiffening elements can be entirely separated or only touch each other at, for instance, the central region. Such stiffening elements can be interrupted at, or start from, positions distributed along an imaginary line that then will define the intended folding line 3 along which the pull-tab will bend and fold when subjected to a force.

(17) In this case the true folding line is allowed to deviate up to around 40 degrees from the intended folding line 3 as the pull-tab 1 may be folded along one or both of the stiffening elements positioned closest to the intended folding line 3. These stiffening elements exhibit an angle of around 40 degrees to the intended folding line 3 (as they exhibit an angle of around 50 degrees to the central stiffening element that is perpendicular to the intended folding line 3). The true folding line will, however, be forced to extend through the central region of the intended folding line 3 (through the hole 12) and can thus be controlled. To control the true folding line in more detail, a stiffening element can be arranged close to and in parallel with the intended folding line 3. Further control of the true folding line can be achieved by arranging parallel stiffening elements on each side of the intended folding line 3.

(18) An example of a suitable way of accomplishing the stiffening structure 7 is embossing a aluminium sheet of 38 μm laminated against 30 μm PE sheet to a embossing depth of 0.2-0.3 mm. An elevation/depression depth of down to 0.1 mm may also be suitable for such a membrane as long as the pull-tab 1 does not fold unintentionally or uncontrolled. The exact depth and shape of the stiffening elements, as well as the exact pattern of the stiffening structure 7, can be adapted to the situation, i.e. to the dimensions and material of the membrane to be used, the size of the pull-tab, the type and size of container, etc.

(19) FIG. 4 shows the sealing membrane 2 secured to the container 5 with the pull-tab 1 pointing upwards. The edge portion 4 of the membrane 2 is folded upwards and has been welded onto the inner walls of the container 5 around its opening 5a. An arrow indicates the intended folding direction for the pull-tab 1. This folding can be carried out as has been done conventionally, but due to the defined intended folding line 3 the folding can now be carried out in a controlled manner. This means that it is possible to predetermine the position of the real folding line created in e.g. an automated folding step in a container assembly production line. The pattern of the stiffening structure 7 can be adapted to the particular requirement for folding line positioning in a particular application, i.e. if it is important to control the exact position of the true folding line the stiffening structure pattern can be adapted so that the intended and the true folding line coincide (e.g. with parallel stiffening elements on each side of the folding line, see above). If the position and extension of the true folding line can be allowed to vary within a certain range, the stiffening structure may have a simpler pattern that only directs the true folding to a certain intended folding zone. In such a case the intended folding line 3 can be regarded as the most probable position for the true folding line.

(20) FIG. 5 shows the sealing membrane 2 and the container 5 according to FIG. 4 but after folding of the pull-tab 1 downwards towards the membrane 2. The pull-tab 2 has now been folded in a controlled manner along its intended folding line 3.

(21) FIG. 6 shows the container assembly 8 with the outer lid 9 attached onto the container 5 with the frame 9b around the container opening 5a and the lid 9b opened. At this stage a user can easily lift and grip the folded pull-tab 1 and tear off the membrane 2.

(22) Fastening of the membrane 2 to the container 5 around the opening 5a may be done by heat adhesion, inductive heat sealing or any other suitable way of sealing the container 5.

(23) Reference signs mentioned in the claims should not be seen as limiting the extent of the matter protected by the claims, and their sole function is to make claims easier to understand.

(24) As will be realised, the invention is capable of modification in various obvious respects, all without departing from the scope of the appended claims. Accordingly, the drawings and the description thereto are to be regarded as illustrative in nature, and not restrictive.

(25) As an alternative to what is exemplified above, the sealing membrane 2 may be secured to a lip extending around the opening of the container 5. In such a case the pull-tab is typically folded downwards on the outer side of the lid/container. Also in such an application it is an advantage to make use of the inventive stiffening structure 7 for defining the intended folding line 3.

(26) Further alternatives are that the pull-tab is placed at a straight part of the membrane, and not in a corner, and that the sealing membrane (and the opening) instead can be rounded (circular or oval).

(27) Further, one or several stiffening elements may be curved to provide stiffness in different directions, and the angles between the stiffening elements, straight or curved, can be varied.

(28) Forming the stiffening structure by heating (e.g. heated forming tools) is typically useful if the sealing membrane is entirely made of a plastic material or is a laminate of e.g. plastics and aluminium where the plastic layer has a sufficient (relative) thickness for retaining the shape of the stiffening structure.