Packaging for Modified Atmosphere Packaging

Abstract

The invention relates to a method for providing a packaging for modified atmosphere packaging, which method includes the steps of: providing an unfolded sheet for folding a box; folding the unfolded sheet to a box having at least an access opening and flange parts bordering the access opening, which flange parts compose an endless circumferential flange; providing a plastic foil; heating the plastic foil; pressing the heated plastic foil against the inner wall of the box and covering the circumferential flange, such that the plastic foil is laminated to the box. The invention further relates to a packaging.

Claims

1. A method for providing a packaging for modified atmosphere packaging, comprising the steps of: providing an unfolded sheet for folding a box; folding the unfolded sheet to a box having at least an access opening and horizontal flange parts bordering the access opening, which flange parts compose an endless circumferential flange; providing a plastic foil; heating the plastic foil; and pressing the heated plastic foil against an inner wall of the box and covering the circumferential flange, such that the plastic foil is laminated to the box.

2. The method according to claim 1, wherein adjacent edges of flange parts abut, such that the flange parts are all arranged in a single plane.

3. The method according to claim 1, wherein adjacent wall parts of the box abut.

4. The method according to claim 1, wherein low pressure is generated between the inner wall of the box and the heated plastic foil for pressing of the foil against the inner wall of the box.

5. The method according to claim 4, wherein the walls of the box are provided with suction openings for creating low pressure between the inner wall of the box and the heated plastic foil.

6. The method according to claim 4, wherein suction openings are provided at corners of the box.

7. The method according to claim 1, further comprising the step of providing a pressing force for pressing the heated plastic foil into the folded box and against the inner wall, wherein the pressing force is generated by providing a pressure difference over the plastic foil.

8. The method according to claim 1, further comprising the step of providing a mould, wherein the unfolded sheet is folded to a box, by pressing the unfolded sheet in the mould.

9. The method according to claim 1, further comprising the steps of: filling the box with foodstuff; providing a sealing foil; and sealing the sealing foil on the circumferential flange, such that the foodstuff is airtight sealed.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0054] These and other features of the invention will be elucidated in conjunction with the accompanying drawings.

[0055] FIGS. 1A-1D shows schematically the steps of an embodiment of the method according to the invention.

[0056] FIG. 2 shows in perspective view a first embodiment of a packaging according to the invention.

[0057] FIG. 3 shows a detail of the embodiment according to FIG. 2.

[0058] FIG. 4 shows a cross sectional view of the embodiment of FIG. 2.

[0059] FIG. 5 shows a perspective view of a second embodiment of a packaging according to the invention.

[0060] FIG. 6 shows a top view of an unfolded sheet for a third embodiment of a packaging according to the invention.

[0061] FIG. 7 shows a detail in perspective view of fourth embodiment of a packaging according to the invention.

DETAILED DESCRIPTION OF THE INVENTION

[0062] FIG. 1A shows a cut unfolded sheet 1 for a packaging according to the invention. This cut unfolded sheet 1 has a bottom 2, wall parts 3 and flange parts 4.

[0063] This cut and unfolded sheet 1 is moved over a mould 5 (see FIG. 1B) and pulled in the mould 5 by sucking the air through the primary suction opening 6. By pulling the unfolded sheet 1 into the mould, the sheet 1 is folded into the desired box shape.

[0064] As soon as the sheet 1 is formed in the mould 5, a plastic foil 7 is transferred over the opening 9 in the box 1. The plastic foil 7 is heated by a heated counter mould 8, also referred to as the upper mould, such that the plastic foil 7 can easily be deformed.

[0065] When the plastic foil 7 is sufficiently heated by the counter mould 8, air is sucked through openings at the corner of the box 1 by the secondary suction openings 10 (see FIG. 10). As a result low pressure is created in the space between the box 1 and the plastic foil 7. Due to this low pressure the plastic foil 7 is pressed against the bottom 2, wall parts 3 and flange parts 4. Simultaneously, the counter mould 8 is pressed into the mould 5, which provides additional pressure for simultaneously pressing the plastic foil 7 against the bottom 2, the wall parts 3 and the flange parts 4. The inner surface 8B of the counter mould 8 may be provided with a plurality of suction openings 8A for sucking the plastic foil 7 against the flat counter mould 8.

[0066] The heated counter mould 8 is provided with a trimming knife 16 for trimming the plastic foil 7 along the edge of the circumferential flange 4.

[0067] The combination of box 1 and laminated plastic foil 7 is then filled with foodstuff 11 and covered by a sealing foil 12. This sealing foil 12 is sealed to the circumferential flange 4 by a sealing tool 13. Before sealing the foil 7 to the flange 4 a gas, for example nitrogen, can be blown between the foodstuff 11 and the sealing foil 12, such that air is replaced by the gas.

[0068] FIG. 2 shows an embodiment of a packaging according to the invention. This packaging has a bottom 2, wall parts 3 and flange parts 4. The wall parts 3 abut at the edges 14. Box suction openings 15 are arranged at the intersection of the edges 14 with the bottom 2.

[0069] As shown in more detail in FIG. 3, the wall parts 3 are kept abutting by the plastic foil 7, which is laminated to the inner wall of the wall parts 3. Because the wall parts 3 abut and do not overlap, these wall parts cannot shift over each other, providing rigidity to the box 1.

[0070] FIG. 4 shows a cross sectional view of the detail of FIG. 3. It is clear that the plastic foil 7 is not pulled completely in the corner 15, but has an acceptable radius limiting the local strain in the plastic foil 7. The curvature of the plastic foil 7 at the corner 15 can be assisted by a suitable mould 5.

[0071] FIG. 5 shows a second embodiment 20 of a packaging according to the invention, which is typically suitable for sandwiches. This packaging 20 has a bottom 21 with wall parts 22 defining an access opening 25 which is bordered by flange parts 23. These flange parts 23 constitute a circumferential flange.

[0072] As the flange parts 23, similar to the previous embodiment, abut at the sides 24, a fully flat circumferential flange is provided. When a plastic foil (not shown) is laminated to the inside of the packaging 20, the abutting wall parts 22 and flange parts 23 are kept in position to provide a rigid box 20.

[0073] The flat circumferential flange 23 enables a reliable and airtight sealing of a sealing foil after the box 20 is filled with foodstuff.

[0074] FIG. 6 shows an unfolded sheet 30 for a third embodiment of a packaging according to the invention. This unfolded sheet 30 has an octagonal bottom part 31 to which wall parts 32 with flange parts 33 are arranged. This unfolded sheet 30 can be used with the method as explained in FIGS. 1A-1D for providing an almost cylindrical packaging.

[0075] A cutout portion 34 is arranged at each intersection of two adjacent wall parts 32 and the bottom part 31. This cutout portion 34 will provide a suction opening for creating a low pressure between the box and a heated foil, which is to be laminated to the box.

[0076] FIG. 7 shows a detail of a fourth embodiment 40 of a packaging of the invention. The figure shows a corner of two wall parts 41 and two flange parts 42. A suction opening 43 is provided at the bottom corner of the wall parts 41.

[0077] The cardboard of the flange parts 42 is provided with two perforation lines 44. At the outer edge of the circumferential flange parts 42, the perforation lines 44 end in a V-shaped cutout 45. These cutouts 45 are also provided in the laminated plastic layer (not shown).

[0078] When the packaging 45 is filled with foodstuff and a sealing layer is sealed to the circumferential flange 42, the packaging 45 can be opened by tearing out part of the flange 42 bordered by the two perforation lines 44. Due to the cutouts 45, the laminating layer will be torn when the cardboard of the flange 42 is torn out. This torn out piece will be taken along with the sealing foil, such that the packaging 40 is opened.

[0079] Another possibility to open the packaging is to provide a tear tab at the sealing foil or to provide a recess in the flange, such that the sealing foil can be gripped.