EP1544127B1 - Package with perforable lid - Google Patents

Abstract

The packaging (10), especially for foodstuffs, has a tub (12) with an upper opening (16) surrounded by a flat rim (20). The opening is covered and sealed by a polymer film (14), secured to the rim by a peripheral weld (22). The sealing film carries a weakened line (24) for a circular section (18) to be pulled clear by a tab (26). The peripheral weld has a stronger hold than the resistance of the weakened film line.

Description

The present invention relates to a package according to the preamble of claim 1.

Nowadays, many food products are packaged in trays or cups initially sealed with a lid. These products can be solid, such as rice, pasta, dishes in sauce. It can also be semi-liquid products such as soups or desserts or liquids such as refreshing drinks or yoghurt.

In known packages, the seal is formed of a polymer film welded to the periphery of the access opening. To access the contents of the package, the seal must be cut or torn off. In particular, it is known, to allow tearing the seal by rupture of the peripheral weld to provide a tongue on the edge of the opening, this protruding tongue can be entered manually by the user to exercise a traction on the lid.

This tongue extending the seal beyond the access opening is sometimes difficult to grasp and the opening of the package by rupture of the peripheral weld is often difficult to obtain. In particular, it requires controlled welding with a sufficiently high breaking strength of the weld to effectively protect the products to be packaged and low enough to allow breakage without the user having to produce too much effort.

The document US-A-3,550,835 described next to the figure 1 a package according to the preamble of claim 1.

The document GB-A-2,156,660 describes a packaging of another type since not welded and not waterproof.

Thus, such packages are not fully satisfactory and are particularly difficult to open.

The invention aims to provide a package whose opening is easier.

For this purpose, the subject of the invention is a package according to claim 1.

According to particular embodiments, the invention comprises one or more of the features of the dependent claims.

• la figure 1 est une vue en perspective d'un premier mode de réalisation d'un emballage avant ouverture ;
• les figures 2, 3, 4 et 5 sont des vues identiques à celles de la figure 1 à des stades successifs d'ouverture de l'emballage ;
• la figure 6 est une vue en perspective d'un autre mode de réalisation d'un emballage selon l'invention avant ouverture ;
• la figure 7 est une vue identique à celle de la figure 6 de l'emballage, lors de son ouverture ; et
• la figure 8 est une vue en perspective d'encore un autre mode de réalisation d'un emballage selon l'invention.

The invention will be better understood on reading the description which follows, given solely by way of example and with reference to the drawings, in which:

• the figure 1 is a perspective view of a first embodiment of a package before opening;
• the figures 2 , 3 , 4 and 5 are views identical to those of the figure 1 at successive stages of opening the package;
• the figure 6 is a perspective view of another embodiment of a package according to the invention before opening;
• the figure 7 is a view identical to that of the figure 6 the packaging, when opened; and
• the figure 8 is a perspective view of yet another embodiment of a package according to the invention.

On the figure 1 there is shown a package 10 for packaging a solid cooked meal or solid food products. Such a package is particularly suitable for a product having undergone sterilization or pasteurization treatment. They are intended to be heated especially in a microwave oven. The package can also be used for packaging liquid or semi-liquid food products or non-food products such as cosmetics, shampoos, adhesives or mechanical components such as screws.

This package consists of a generally circular tray 12 and a flexible cover 14 for closing a passage or access opening 16 inside the tray 12.

The tray consists of a thermoformed polymer film. It is relatively rigid and in particular self-supporting, so that it retains its shape whether or not it is filled with a container, such as a food product. The tray 12 is for example made of an outer support layer of suitable material, for example polyvinyl chloride (PVC), covered on its inner surface with a weldable layer, by example polyethylene (PE). The tray is, alternatively, formed of a thermoformable polymer such as amorphous polyester (APET), polypropylene (PP), polystyrene (PS), or an amorphous polyester complex (APET) / polyethylene (PE).

The tray defines a receptacle 18 bordered around its entire periphery by a flange 20 delimiting a flat surface for welding the lid 14 along a peripheral weld 22.

The lid 14 is made of a flexible polymer film formed of one or more superimposed layers. The cover 14 has a shape identical to the outer periphery of the peripheral rim of the tray and more exactly a shape identical to that of the weld 22. Thus, no external gripping tab extends the lid outwards beyond the weld 22 in the extension of a weakening line.

Initially, the lid is held taut on the rim 20 across the access opening 16. In particular, the lid is kept away from the food products contained in the package, so that a space free 23 ( Figure 4 ) filled with air or any other gas is interposed between the lid and the food products contained in the package and resting on the bottom of the tray.

The gas contained in the free space 23 may be at atmospheric pressure, at a higher pressure or at a lower pressure. In the latter case, a more or less intense vacuum is created in the packaging during its sealing.

According to the invention, the cover 14 comprises, out of the peripheral weld 22, in the region of coverage of the access opening 16, a weakening line 24 of the cover. This weakening line 24 is non-through in the thickness of the lid. The weakening line and the seal 22 of the lid on the container are such that the breaking strength of the lid along the line of weakness is lower than the breaking strength of the weld during application. pressure on the lid.

Preferably, the tensile strength of the cap on either side of the line of weakness is between 1 N / 15mm and 70N / 15mm and preferably between 2N / 15mm and 25N / 15mm.

In the embodiment of the figure 1 , the weakening line 24 delimits a closed contour and its path is totally comprised in the region of coverage of the access opening 16. The closed contour delimits a profile generally corresponding to the profile of the rim 20 bordering the passage 16.

More specifically, in the embodiment shown, the line of weakness 24 delimits a generally circular profile and locally has a tongue 26 protruding from the general outline of the line of weakness to the outside.

This tongue has a generally concave profile of substantially constant curvature. It has dimensions generally corresponding to the dimensions of the end of a finger of a human being. Thus, this tongue has a width of between 2 cm and 5 cm and a length of between 2 cm and 5 cm.

The weakening line 24 delimiting the tongue has advantageously but not necessarily at least one angular tip not shown forming an acute angle adapted to promote the rupture of the lid.

The cover 14 has a visible marking identifying the position of the line of weakness 24. In the embodiment illustrated in FIG. figure 1 , this marking is constituted by a discontinuous black line printed on the cover.

The weakening line 24 is produced by processing the film constituting the cover 14.

According to a first embodiment, the weakening line 24 is produced by applying a high energy radiation such as a laser, by applying a laser beam along the line of the weakening line 24, before the 14 is placed on the tray. The treatment with high energy radiation is performed on one or more films of the cover 14 when it comprises several.

According to another embodiment, the weakening line is formed by a mechanical fading of the cap extending along the line of the weakening line 24. This mechanical treatment is performed on one or more films of the operculum when it has more than one.

According to a first example, a microporous weakening is provided along a band of reduced width to at least partially form the weakening line 24. Such a microporous strip of a film is obtained for example by passing the film of the cap between two rolls, of which one of the rolls was made abrasive along the line of the weakening line. Such a treatment is described for example in the document FR-2717449 .

In a second example, the mechanical weakening is formed by notching the thickness of one or more films of the cover when it comprises more than one film. These cuts are made by a matrix of cutting elements, the seal being compressed between this matrix and a support, as known per se.

According to yet another example, the line of weakness is obtained by a line of non-through micro-perforations through the lid, these micro perforations being formed through one or more films when the lid has several.

According to a particular embodiment, the weakening of the cap along the line of weakness is variable depending on the position along this line of weakness. For example, the attenuation is greater in the region of the edge of the tongue 26 than on the generally circular periphery bordering the peripheral weld.

These differences of attenuation are obtained for example by local combination of several attenuation treatments on one or more films constituting the operculum, or by implementation of a weakening treatment more or less deep or more or less dense following the regions of the weakening line 24. This more or less dense or deep treatment is particularly well achieved by subjecting the film to high energy radiation.

According to a first embodiment, the cover 14 is monolayer and is formed of a base film of polymer or paper. Thus, the cover 14 is a single-material seal. In order to ensure its connection to the edge of the tray, the film of polymer or paper forming the seal is advantageously covered on its inner surface with a sealing material affixed for example by extrusion, coating, coextrusion or coating. when applying printing ink on the base film.

The base film is preferably formed of a biorented co-extruded polymer film. It can also be a mono-oriented or non-oriented film obtained by coextrusion. This film is formed for example of polypropylene (OPP), polyester (OPET), or polyvinyl chloride (PVC). The thickness of the base film is generally between 5 and 500 microns and preferably between 15 microns and 150 microns.

The sealing material is selected compatible with the material forming the tray to allow welding. Typically, the thickness of the sealing material is between 10 and 40 microns, the amount of the deposit of sealing material being between 1 and 12 g / m ² .

In this case, the embrittlement is formed in the base film.

According to a second embodiment, the cover 14 is formed of two complexed films. Thus, the seal comprises a base film formed of polymer or paper associated with its side facing the tray to a polymer sealing film compatible with the tray material to allow welding.

The base film and the sealing film are bonded to one another by complexing with an adhesive or resin extrusion.

The base film is advantageously formed of a bioriented polymer film. However, this film can also be a cast film. The polymer forming the base film is preferably polyester (PET), polyamide (OPA) or polypropylene (OPP).

The sealing film is formed for example of polyethylene (PE) optionally mixed or co-extruded with other polymers. The sealing film is, alternatively, formed of polypropylene (PP), preferably cast (cast), homopolymer type or copolymer with ethylvinylacetate (EVA).

According to another variant, the sealing film is made of amorphous polyester or copolyester (PETG).

When the lid is formed of two complexed films, the film facing the tray advantageously receives on its side in contact with the tray a sealing varnish, as in the case of a single-material seal.

In this embodiment, where the lid is formed of two films, the embrittlement is performed on the outer layer and possibly on part of the thickness of the inner layer. According to a particular embodiment, the outer film is weakened by high energy radiation treatment while the inner film is weakened by mechanical treatment such as a microporous weakening or vice versa. The same mechanical treatment or high energy radiation is, alternatively, provided on the two films.

Alternatively, the cover 14 is formed of a bilayer complex film formed for example of polyester (PET) / polypropylene (PP), aluminum / polyester film (PET), oriented aluminum / polypropylene film (OPP) or paper / polypropylene (PP) layer.

The polyethylene films are advantageously complexed by coextrusion with a small thickness.

According to another embodiment, the lid comprises three films, the two end films of which are as defined above in a lid formed of two films, an intermediate film being interposed between the two extreme films.

This intermediate film is formed for example of an aluminum sheet of 6 to 100 microns and preferably 7 to 38 microns. This aluminum foil is annealed or hardened.

Thus, the cover is formed for example of polyester (PET) / aluminum / cast polypropylene (PPC) or polyester (PET) / aluminum / polyethylene (PE) or oriented polyamide (OPA) / aluminum / polypropylene (OPA) / aluminum / cast polypropylene (PPC) or oriented polyamide (OPA) / aluminum / cast polyethylene (PEC).

As a variant, the intermediate film is a biaxially oriented film, for example a polyamide film oriented in particular in a polyester (PET) / polyamide (OPA) / polypropylene (PP) and polyester (PET) / polyamide (OPA) / polyethylene (PE) structure. ).

When the lid has three films, the intermediate film is advantageously weakened by treatment with high energy radiation along the line of weakness.

According to another variant, the lid is formed of three films and is composed for example of polyester (PET) / polypropylene (PP) / polyester (PET).

Such a package opens as follows.

While the package is placed on a flat surface from the bottom of the tray, the user pushes the tongue 26 of the lid inside the package by pressing with his finger, as shown in the illustration. figure 2 . Since the contents of the package are not present immediately beneath the lid, the latter may be deformed inwards, causing the initiation of its rupture along the line of weakness 24 without the lid becoming inoperable. contact with the product contained in the packaging and resting on the bottom of the tray.

The breaking strength of the seal is lower along the line of weakness than the breaking strength of the weld, the film breaks in the vicinity of the finger of the user. In particular, the curvature of the tongue being relatively large, the rupture of the lid is effected along the contour of this language.

During the initial perforation of the lid by pressing with the finger, a characteristic noise such as "pop" is audible to the user due to the passage of gas contained in the tray through the broken lid when the pressure of this gas is greater than the atmospheric pressure.

Similarly, a characteristic noise is also audible to the user during the initial rupture of the lid when the initial pressure in the package is lower than the atmospheric pressure. This noise results from passage of the air from the outside of the package inwards through the broken lid.

If necessary, the packaging is placed in a microwave oven while the operculum is broken only on the edge of the tongue. Under the action of the radiation in the microwave oven, the products contained in the package heat up and a gas release occurs through the opening formed at the tongue 26. In addition, this language heats up and tends to bend towards the outside of the package, as shown on the figure 3 .

After the package has been taken out of the oven, the user easily grasps the tongue thus deformed and pulls on the part of the lid delimited by the line of weakness 24. Thus, the lid gradually breaks along this line of weakening, as illustrated on the figure 4 until the central area of the lid is completely detached, as shown in figure 5 thus allowing access to the food product contained in the package.

Alternatively, the package is placed in a microwave oven before the seal is broken. Microwave radiation causes heating of the products contained in the package, so that the pressure in it increases. Under the action of the pressure in the package, the lid is urged outwards until it breaks along the line of weakness, especially on the edge of the tongue 26. After removal of the microwave oven, the detached portion of the lid is torn and completely detached from the rest of the package, as shown in the figure 5 .

On the Figures 6 and 7 another embodiment of a package according to the invention is shown.

In this embodiment, elements identical or similar to those of the first embodiment are designated by the same reference numerals.

Here the tray 12 is replaced by a cup designated by the same reference number, the cup being deeper than the tray and being adapted to receive a liquid.

In addition, the weakening line, denoted 124, defined on the surface of the lid 14 forms a transverse line extending in the region of coverage of the access opening between two distinct points of the peripheral weld 16. More specifically, this weakening line 124 connects two opposite points of the perimeter of the access opening. It has a generally arcuate shape having, in its middle part, a tongue 126 of shape comparable to the tongue 26 of the previous embodiment.

In this embodiment, the tongue 126 has, along its contour, an angular tip 128 facilitating the initiation of the rupture of the lid along the line of weakness.

When the operculum is squeezed, for example by pressing a finger on the surface of the tongue 126, the operculum first breaks along the point 128. The rupture propagates along the contour of the tongue 126 on both sides of it. The operator then enters the tongue 126 and pulls the part of the detached cover, as illustrated on the figure 7 . Thus, it causes the complete rupture of the lid along the line of weakening 124 and the progressive delamination of the peripheral weld 22. This delamination causes the updating of a range noted 130 of the flange initially covered by the lid. This newly exposed beach allows the user to place the lips on a clean surface to drink the liquid contained in the cup.

In this embodiment, the lid is advantageously formed of a complex film comprising three layers formed for example of polyester (PET) / aluminum film / polyethylene (PE) or oriented polypropylene (OPP) / aluminum film / polyethylene (PE). In a variant, the cover consists of a complex film comprising at least two layers, for example polyester (PET) / polyethylene (PE), oriented polypropylene (OPP) / polyethylene (PE) or paper / polyethylene (PE).

The materials described for the packaging of Figures 1 to 5 can also be advantageously used.

In this embodiment, the weakening line 124 is made according to one of the methods envisaged for the preceding embodiment.

On the figure 8 another embodiment of a package according to the invention is shown. In this embodiment, the line of weakness 124 extends only in the range of the operculum covering the access opening. Thus, the weakening line does not extend on the peripheral weld 22. Here, the weakening line delimits an unclosed contour. In particular, it forms a tongue 126 extended laterally on both sides by two curved sections.

The line of weakness allows the partial opening of the lid to introduce an object or a substance in the package. Thus, the opening in the lid allows for example to introduce a straw. It also makes it possible to add in the packaging certain substances, such as sugar or salt. It also allows the introduction of an organ for mixing, such as a spoon or a rigid stirrer.

Claims (17)

1. Packaging (10) comprising a container (12) in the form of a dish delimiting an access opening (16) bordered by a peripheral band (20) for the fused bonding of a lid (14), and a flexible lid (14) for the initial sealing of the access opening (16), which lid (14) is maintained on the band (20) along a continuous peripheral fused bond (22), the lid (14) comprising, away from the peripheral fused bond (22), in a region covering the access opening (16), a line (24; 124) for weakening the lid which does not pass through the lid, characterised in that said lid (14) does not have a gripping tab which extends the weakening line outwards beyond the peripheral fused bond (22), and the weakening line (24; 124) and the fused bond (22) of the lid on the container (12) are such that the tear strength of the lid (14) along the weakening line (24; 124) over the entire thickness of the lid is lower than the tear strength of the fused bond (22) on application of a pressure to the lid, and in that the tear strength of the lid is such that pushing the lid inside the packaging by pressing with a finger causes the lid to start to tear along the weakening line (24) over the entire thickness of the lid.
2. Packaging according to claim 1, characterised in that the weakening line (24) extends along a path which is wholly contained within the region covering the access opening (16).
3. Packaging according to claim 2, characterised in that the weakening line (24) delimits a closed outline which is wholly contained within the region covering the access opening (16).
4. Packaging according to claim 1, characterised in that the weakening line (124) forms a line which extends at least in the region covering the access opening (16), between two separate points of the peripheral fused bond (22).
5. Packaging according to any one of the preceding claims, characterised in that the tensile strength of the lid along the weakening line (24; 124) is from 1 N/15 mm to 70 N/15 mm.
6. Packaging according to any one of the preceding claims, characterised in that the weakening line (24; 124) delimits a tongue (26), the dimensions of which correspond substantially to the dimensions of a human finger.
7. Packaging according to claim 6, characterised in that the weakening line (24; 124) forms at least one angular point (128) on the contour of said tongue (26).
8. Packaging according to any one of the preceding claims, characterised in that the lid (14) has a visible marking for identifying the position of the weakening line (24; 124).
9. Packaging according to any one of the preceding claims, characterised in that the lid (14) has, along the weakening line (24; 124), at least one mechanical weakening treatment on at least one film of the lid.
10. Packaging according to claim 9, characterised in that said mechanical weakening treatment comprises microporous weakening.
11. Packaging according to claim 9 or 10, characterised in that said mechanical weakening treatment comprises partially cutting at least one film of the lid (14) with the aid of a matrix of blades along the path of the weakening line (24).
12. Packaging according to any one of the preceding claims, characterised in that the lid (14) has, along the weakening line (24; 124), a weakening treatment by high-energy radiation along at least one film of the lid.
13. Packaging according to claim 12 and any one of claims 9 to 11, characterised in that the lid comprises at least two complexed films, the first film having undergone mechanical weakening treatment along the path of the weakening line (24), the second film having undergone weakening treatment by being subjected to high-energy radiation along the path of the weakening line (24).
14. Packaging according to any one of the preceding claims, characterised in that the lid (14) is a complex in which the combination of films is selected from the group comprising polyester (PET)/polyamide (OPA)/polypropylene (PP), polyester (PET)/polyamide (OPA)/polyethylene (PE), polyester (PET)/polypropylene (PP), aluminium/polyester (PET), aluminium/oriented polypropylene (OPP), layer of paper/polypropylene (PP), polyester (PET)/aluminium/cast polypropylene (CPP), polyester (PET)/aluminium/polyethylene (PE), oriented polyamide (OPA)/aluminium/cast polypropylene (CPP), oriented polyamide (OPA)/aluminium/cast polyethylene (CPE), polyester (PET)/polypropylene (PP)/polyester (PET), polyester (PET)/aluminium/polyethylene (PE), oriented polypropylene (OPP)/aluminium/polyethylene (PE), polyester (PET)/polyethylene (PE), oriented polypropylene (OPP)/polyethylene (PE), and paper/polyethylene (PE).
15. Packaging according to any one of the preceding claims, characterised in that the weakening line (24; 124) is in such a form that, when it is initially torn, a sound is emitted under the action of a gas flowing through the torn lid (14).
16. Packaging according to any one of the preceding claims, characterised in that it comprises a product contained in the container (12) and resting on a face of the container remote from the lid (14), and in that a free space (23) filled with a gas is defined between the lid (14) and the product, which free space (23) is sufficient to allow deformation of the lid inside the container (12) to initiate tearing of the lid (14) without the lid coming into contact with the product.
17. Packaging according to any one of the preceding claims, characterised in that the weakening line (24) has a tear strength by application of a pressure to the lid (14) that varies along the length of the weakening line (24).

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