WO1992020591A1

WO1992020591A1 - Package with heat sealed multilayer lid, removable in one operation

Info

Publication number: WO1992020591A1
Application number: PCT/DK1992/000151
Authority: WO
Inventors: Steen Pedersen
Original assignee: K. B. Trykko A/S
Priority date: 1991-05-15
Filing date: 1992-05-08
Publication date: 1992-11-26
Also published as: AU1876092A; DK91691D0; EP0583430A1

Abstract

A package (5) consists of a cup (8) with a lid (9) and serves to store and distribute e.g. food products, such as salads. The lid is constructed as a laminate of a plurality of layers which are permanently bonded together. In the mounted state, the lid is positioned in a recess (21) defined by an upstanding edge (19) wich is reinforced with a flap (20). When the package (5) has been filled by the producer, the lid (9) is heat sealed on an outwardly extending flange (18) on the cup (8) by means of a binder forming a connection with the container of a strength which is sufficiently great to seal the container with certainty, without being so great that the lid is deformed permanently when torn off, so that the lid can be reused for closing the package sufficiently tight again for continued storage of the residual contents in a hygienic manner.

Description

Package with heat sealed multilayer lid, removable in one operation.

The invention concerns a package in the form of a con- tainer with a lid of the type consisting of several layers, which comprise at least one impermeable bottom layer with a binder to secure the layer to the filled container to seal it hermetically, an intermediate layer having printed thereon a message which may e.g. consist of a text and an illustration of the packaged product, as well as a top layer serving to protect the subjacent layers, an upstanding edge being provided along the peri¬ phery of the container, the layers of the lid being per¬ manently bonded together to a laminate which is so stiff that the lid when fixed can be detachably kept in position in the opening defined by the said upstanding edge on the container.

Packages of this type are widely used today for distribu- tion of food products in particular. To protect these food products against contamination and to ensure to them a satisfactorily long shelf life, the package, immediately after filling by the producer, is provided with a separate cover sheet of plastics or aluminium which is sealed on to the container and closes it hermetically. On top of the cover sheet is then placed a sheet of loose, printed paper with e.g. a specification of the product, an instruction on how to prepare the product and generally also an illu¬ stration of it. Finally, most outwardly there is provided a detachable plastics lid which can be squeezed by a snap closing mechanism about a flange or a bead which is formed along the periphery of the container.

When the product is to be used, the plastics layer and the loose sheet of paper are first removed, and then the cover sheet is torn off by pulling a flap and is discarded. The contents of the package are now freely accessible and can be used as required. When the consumer has taken the de¬ sired quantity out of the package, the package can be closed again with the plastics lid, which provides suffi- cient protection for the rest of the product to keep for some time more if the product is stored sufficiently cool in e.g. a refrigerator or a freezer.

This known type of package fully meets the requirements made with respect to distribution of e.g. food products in a hygienic and non-deteriorating manner and identification of these, as well as with respect to the possibility of continued use of these even after the package has been opened. However, because of the various loose parts of which the lid is composed, the package is expensive to manufacture and cumbersome and time-consuming to use for the producer as well as the consumer.

In an attempt to remedy these drawbacks the patent speci- fication GB 2 052 455 proposes a lid structure comprising the same layers as the above-mentioned known lid, the layers being now moulded together with a plastics rim which likewise has a snap closing mechanism for detachably securing the lid to the container. In this case too the bottom layer consists of a cover sheet which seals the container hermetically when the container has been filled by the producer. However, this lid structure is adapted so that the cover sheet remains in position on the container when the lid is removed. Therefore, like before, the con- sumer must separately tear off the cover sheet from the container the first time its contents are to be used, and, as mentioned, this is a cumbersome and time-consuming ope¬ ration which is frequently made difficult because the thin sheet tends to break in the tearing process. The US Patent Specification 3 351 265 discloses a con¬ tainer with a lid of a suitable stiff material which may have an impermeable bottom layer on the underside. This structure does not involve a permanently bonded laminate with several layers. The container has an upstanding edge along the periphery to keep the lid in position by fric- tional engagement when the container is closed again after having been opened the first time. This solution entails that the lid may be peeled off in one operation and be applied again by being pressed down over the opening of the container and fixed here by the upstanding edge of the container by friction. However, in the opening operation the lid may be permanently deformed when the seal is broken by an upward pull in the lid with a tearing force which generally has a direction of action substantially perpendicular to the face of the lid. This impedes re- application of the lid, and the hand used by the user for this purpose can easily touch the packaged product in an unhygienic manner when the user in the application opera- tion, the user must simultaneously try to smooth out the deformed lid.

Accordingly, today there is a great need for a new lid structure which can be used for packages of the type men- tioned in* the opening paragraph, and which has all the advantageous properties of these, but is cheaper to manu¬ facture and more easy, quick and hygienic to use for the producer as well as the consumer.

Accordingly, the lid structure of the invention is novel and unique in that the binder for securing the lid to the filled container consists of a binder, such as lacquer, wax, plastics or a similar material, applied to the under¬ side of the bottom layer and forming, when the lid is pressed against one or more upwardly directed binding faces on the container under the action of heat, a connec- tion with a strength sufficiently great to hermetically seal the container with certainty, without being so great that the lid is subjected to considerable permanent de¬ formations in the tearing operation. The lid can hereby be removed from the container without receiving permanent de¬ formations and therefore be applied again easily and readily in a single movement of the hand. The previous cumbersome and time-consuming operation in many container structures of separately removing the thin and rather vulnerable cover sheet has thus been eliminated complete¬ ly, and to this should be added the considerable advantage that the impermeable properties of the cover sheet are still present in the lid, even after the lid has been re¬ moved the first time and the package has thus been opened. The cover sheet, which was just discarded in the past as soon as the seal had been broken, is thus still of use in the overall life of the package of the invention.

In an advantageous embodiment the strength of the connec- tion between the bottom layer and the container may be adjusted by providing the binder in a strip, which is po¬ sitioned along the periphery of the lid and has a width corresponding to the specific binding capacity of the binder.

The invention will be explained more fully in the follow¬ ing description of non-limitative embodiments and of addi¬ tional advantageous properties and technical effects, with reference to the drawing, in which

fig. 1 shows a first embodiment of a package according to the invention, seen from above with part of the lid re¬ moved.

fig. 2 is a sectional lateral view of the same. fig. 3 shows a second embodiment of a package according to the invention, seen from above with part of the lid re¬ moved,

fig. 4 is a sectional lateral view of the same,

fig. 5 is a top view of the lid for the package shown in figs. 3 and 4,

fig. 6 is an enlarged view of a fraction of the laminate of which the lid according to the invention is composed,

fig. 7 is an enlarged cross-sectional view of a fraction of the package shown in figs. 1 and 2,

fig. 8 is an enlarged cross-sectional view of a fraction of the package shown in figs. 3 and 4, and

fig. 9 shows the same, but with the binder on the under- side of the lid confined to a narrow stip along the peri¬ phery.

An example of a first embodiment of a package 1 according to the invention is shown in figs. 1 and 2 as a plastics cup 2 with a lid 3. Cups of this type are very popular today for distribution of many food products, such as salads, since the cup can easily be closed again when the seal has been broken and part of the contents has been consumed. The rest can therefore be stored in a hygienic and non-deteriorating manner in the cup in e.g. a refrige¬ rator for later use. For this purpose the lid 3 is pro¬ vided with a snap closing mechanism 4, which is known per se and will therefore not be mentioned in greater detail.

Figs. 3 and 4 show a second embodiment of a package 5 according to the invention. In this case too the package consists of a plastics cup 8 with a lid 9 for salads and similar food products. The lid has a flap 10 for pulling when the lid is to be removed, and this embodiment of the package moreover comprises a special closing mechanism 11, which will be described more fully later. In fig. 5 the actual lid 9 is shown in unfolded state with the flap 10 clearly visible.

In both embodiments the lid 3; 9 is composed of a laminate a fraction of which being shown on an enlarged scale in fig. 6. In the shown example the laminate consists of an impermeable thin bottom layer 12, an intermediate layer 13 and a top layer 14. However, other embodiments may include more layers, and within the scope of the invention it is also possible to have a laminate with just two layers.

Usually, the upper side of the intermediate layer 13 has printed thereon a message serving to illustrate the packaged product and to give instructions of its use, etc. In this connection the top layer serves to protect the ink effectively. Furthermore, a binder (not shown) is applied to the underside of the bottom layer 12 to seal the lid to the container. This binder may be lacquer, wax, plastics or a similar material suitable for a heat sealing process.

The function of the laminate appears more clearly from fig. 7, which is an enlarged view of a fraction in cross- section of the first embodiment of the package 1 shown in figs. 1 and 2. As will be seen, the lid substantially con¬ sists of a laminate which is composed of a bottom layer 12, an intermediate layer 13 and a top layer 14. A binder 16 is applied to the underside of the bottom layer 12, and a printed message, whose ink 15 is protected by the top layer 14, is provided on the upper side of the interme¬ diate layer 13. In this embodiment the top layer is made of injection moulded or vacuum formed plastics, which is peripherally provided with a downwardly facing collar in the form of a snap lock 4 engaging, in a known manner, with an outwardly directed flange 17 on the cup 2 in the applied state of the lid.

When the cup 2 has been filled with the desired product by the producer, the lid 3 is applied and heat sealed to the flange 17. The product is now hermetically protected in the package and can withstand the subsequent transport and distribution through the various links without being con- taminated. When the contents are to be used by the. final consumer, the consumer quite simply peels off the l-id, the laminated bottom layer automatically following the lid up¬ wardly instead of, like in the conventional structures, remaining on the cup, which necessitates further opera- tions to open the package. These operations may moreover be extremely unpleasant and unhygienic since the user's fingers will necessarily be in close contact with the con¬ tents of the package.

In contrast, the contents in the package shown in fig. 7 are readily accessible as soon as the lid has been peeled off. The user can now use the desired quantity of the con¬ tents, and then the lid 3 can be applied firmly to the cup 2 by means of the snap lock 4 in a single movement of the hand. The* rest of the contents in the package can hereby be stored in a sufficiently non-perishable manner in e.g. a refrigerator, because the package still provides the necessary protection against contamination or drying up of the product.

A large range of suitable materials is available for the production of the various layers of the laminate. Thus, for the intermediate layer 13 there may advantageously be used paper or cardboard, which are relatively inexpensive materials which moreover form an excellent base for the printing of the producer's message in e.g. colours on off- set printing machines.

Figs. 8 and 9 show an enlarged view of a fraction in cross-section of the package 5 shown in figs. 3, 4 and 5, said package consisting of a cup 8 and a lid 9. Like in the embodiment described above, the lid 9 is composed of a laminate with a bottom layer 12, an intermediate layer 13 and a top layer 14. The producer's message 15 is provided on the upper side of the intermediate layer 13 and is pro- tected by the top layer 14, which is a relatively . hin layer in this case and preferably consists of overprint varnish, but may moreover be of wax, plastics or a similar material. The underside of the bottom layer 12 has applied to it a binder 16 which may consist of lacquer, wax, plas- tics or a similar heat sealing material. In fig. 8, this binder is distributed over the entire surface of the bottom layer, while in fig. 9 it is just present in a narrow stip along the periphery.

Further, in this case too the bottom layer 12 may consist of a plastics or metal sheet, while the intermediate layer 15 consists of cardboard which per se is a relatively stiff material imparting to the lid 9 a stiffness which is utilized in the special closing mechanism, which is unique to this embodiment of the package of the invention.

After filling by the producer the lid 9 is applied to the cup 8 and heat sealed on an outwardly facing flange 18 along the periphery of the cup. This flange 18 is provided with an upstanding edge 19, which is stiffened with a flap 20 and which defines a recess 21 in which the lid 9 is positioned in the mounted state. The lid 9 extends right out to the upstanding edge 19, which thereby keeps the lid fixed with a suitable light pressure force, which the lid is capable of absorbing in its plane because of the stiff¬ ness imparted to the lid by the cardboard of the interme- diate layer 13. This provides a simple, but effective and tight closing mechanism, which automatically begins func¬ tioning when the user, having broken the seal, again puts the lid 9 down in the recess 21 of the cup 8.

Of course, it is of utmost importance that the binder 16 has a sufficiently great strength to be able to seal the package hermetically with certainty and to maintain this seal even with the relatively rough handling to which packages of this type are frequently subjected on their travel from the producer to the consumer. However, the seal must not be so strong that the lid is deformed perma¬ nently when torn off, since the subsequent closure will not be satisfactory if the lid has been bent and therefore does not fit sufficiently closely to the upstanding edge 19 of the cup 8.

However, in the package shown in fig. 8 a binder may be used which has a smaller specific binding power than is the case in the conventional structures which employ a separate thin plastics or metal sheet which, in contrast to the stiff lid of the invention, is not capable of dis¬ tributing an outer impact over a greater binder area.

In the embodiment shown in fig. 9 the binder 16 is pro¬ vided in a small strip alone along the periphery of the lid. In this case too the stiffness of the lid is utilized for distribution of outer impacts, if any, over an overall greater part of the binder, which can therefore be se- lected with a relatively great strength, the binding power being then adapted by adjusting the width of the strip.

Claims

P a t e n t C l a i m s

1. A package in the form of a container with a lid of the type consisting of several layers, which comprise at least one impermeable bottom layer with a binder to secure the lid to the filled container to seal it hermetically, an intermediate layer having printed thereon a message which may e.g. consist of a text and an illustration of the packaged product, as well as a top layer serving to pro¬ tect the subjacent layers, an upstanding edge being pro¬ vided along the periphery of the container, the layers of the lid being permanently bonded together to a laminate which is so stiff that the lid when fixed can be detach- ably kept in position in the opening defined by the said upstanding edge of the container, c h a r a c t e r ¬ z e d in that the binder for securing the lid to the filled container consists of a binder, such as lacquer, wax, plastics or a similar material, applied to the under- side of the bottom layer and forming, when the lid is pressed against one or more upwardly directed binding faces on the container under the action of heat, a connec¬ tion with a strength sufficiently great to hermetically seal the container with certainty, without being so great that the -lid is subjected to considerable permanent defor¬ mations in the tearing off operation.

2. A package according to claim 1, c h a r a c t e r ¬ i z e d in that the binder to secure the lid to the filled container is just applied to the underside of the bottom layer in zones which correspond to or are smaller than the upwardly directed binding face or faces on the container.

3. A package according to claim 1 or 2, c h a r a c ¬ t e r i z e d in that the intermediate layer of the lid consists of cardboard.

4. A package according to claim 1, 2 or 3, c h a r a c ¬ t e r i z e d in that the intermediate layer of the lid consists of rigid foamed plastics.

5. A package according to one or more of claims 1-4, c h a r a c t e r i z e d in that the top layer consists of a thin layer of lacquer, wax, plastics or a similar material.

6. A package according to one or more of claims 1-5, c h a r a c t e r i z e d in that the bottom layer con¬ sists of plastics or metal.