EP1792844A1

EP1792844A1 - Hermetically sealed display container

Info

Publication number: EP1792844A1
Application number: EP06124917A
Authority: EP
Inventors: Walter Sintoni
Original assignee: Ipack Srl
Current assignee: IPACK S.R.L.
Priority date: 2005-11-30
Filing date: 2006-11-28
Publication date: 2007-06-06
Anticipated expiration: 2026-11-28
Also published as: PT1792844E; DE602006000537D1; ES2302300T3; DE602006000537T2; EP1792844B1; ITBO20050726A1; ATE385968T1; DK1792844T3

Abstract

A container (1) for perishable products comprises a tray (2) delimited by a base (3) and lateral walls (4) which together surround a cavity (5) for receiving products; the lateral walls (4) have a top edge (6) which runs continuously along the container (1) border; the container also comprising a shell-shaped annular element (7) which is associated by overlapping with the top edge (4) of the lateral walls (4) and which has a continuous, smooth exterior surface (8) designed to constrain to it a container (1) airtight sealing barrier (9). The exterior surface (8) of the shell-shaped annular element (7) has a groove (10) along it, running without interruption along the top edge (6) of the container (1) and dividing the exterior surface (8) into two strips (11, 12) on either side of it, the strips being designed to constrain the airtight sealing barrier (9) independently of one another.

Description

The present invention relates to an improved hermetically sealed display container for perishable products, in particular for foodstuffs.
In a display container for foods perishable on contact with air, the product in the container compartment is protected by isolating the compartment from the outside environment with an isolating barrier associated with the container and by creating a vacuum or controlled atmosphere in the compartment.
The isolating barrier is designed to prevent air from entering from the outside (for example when a vacuum has been created in the container) or to prevent inert gases (which may have been introduced into the compartment to prevent air from reaching the product, oxidising it and/or in any case accelerating its deterioration) from escaping from the compartment towards the outside environment around the container.
The barrier is normally obtained by applying to the container a thin film of plastic material which is stretched over the contents of the container, extended under its edges and sealed or glued continuously to the edges of the container.
In the case of containers with very flat, smooth edges (for example plastic containers obtained by means of thermoforming in a mould), continuous film sealing is easy, so isolation of the container compartment is relatively easy and lasting.
In contrast, in the case of containers obtained by erecting a flat sheet of cardboard, card or other equivalent material, obtaining a barrier seal able to guarantee the container hermetic seal is much more difficult.
The erection process is responsible for creating characteristic wrinkling of the surface of the material, mainly concentrated around the concave corners, delimited by two adjacent lateral walls of the container and around the convex corners delimited by the edge of the container and by the lateral walls.
These wrinkles are caused by local bending and overlapping which the material used to make the sheet must be subjected to if it is to assume - from being flat - a spatial configuration in particular with a curved and/or bent lateral surface.
Since such wrinkles are potential channels for intercommunication between the container compartment and the surrounding outside environment, the creation of a local hermetic seal at them is very problematic. So much so that the Applicant has developed his own technology (the subject matter of prior patent EP 1365964 ) providing a solution not just to other problems deriving from container annular reinforcement, but also to the problem of how to obtain a container seal suitable for allowing their use as airtight containers for foodstuffs that are fresh and/or highly perishable in contact with the surrounding air.
Said technology solves the above-mentioned problems by producing special reinforcement edges which have particular shell-like geometric shapes designed to continuously overlap and wrap around the top parts of the container lateral walls. Such edges have concave interior surfaces, designed to adhere, with substantially mating surface contact, with the container lateral walls below and they have convex, smooth exterior surfaces, which give the container as a whole a continuous, smooth border, against which the sealing film can easily be sealed, without interruptions, along the entire border of the container, thus guaranteeing a satisfactory container hermetic seal.
Such a prior art solution has provided - in industrial practice - widely satisfactory results. However, it can be further improved on and these improvements form the specific subject matter of the present invention.
The main aim of the present invention is therefore to make improvements to the prior art containers designed to further increase the effectiveness of the hermetic seal and to make it even longer lasting, so as to allow not just improvement of the performance of prior art containers, but also an expansion of the range of use, so that they can be used as display containers for more perishable fresh foodstuffs.
The present invention also has for an aim to increase - at the same time as achieving improved seal conditions - the stiffness of the prior art containers, thus allowing them to be less deformable if they contain a large quantity of product and/or if the packs of products using such containers are handled in a way that is not particularly delicate and careful.
The invention also has for an aim to provide relatively inexpensive containers with a relatively low weight.
Accordingly, the present invention provides a container whose technical features can clearly be inferred from the content of the claims herein, in particular claim 1 and any of the claims directly or indirectly dependent on claim 1.
The advantages of the invention are more apparent from the detailed description which follows, with reference to the accompanying drawings which illustrate a preferred embodiment of the invention provided merely by way of example without restricting the scope of the inventive concept, and in which:

Figure 1 is an exploded assembly view of a container in accordance with the invention;
Figure 2 is an assembly view of the container of Figure 1, completely assembled;
Figure 3 is a top plan view of the container, with some parts cut away to better illustrate others;
Figure 4 is a cross-section of the container of Figure 3 in a plane marked by the line A - A in Figure 1;
Figure 5 is an enlarged detail from Figure 4.

With reference to Figure 1, the numeral 1 denotes as a whole a hermetically sealed display container for perishable products, in particular for foodstuffs, basically consisting of two fundamental components, respectively a tray 2 and an annular element 7, which can be associated with one another to form a whole, illustrated in Figure 2.
More specifically, the tray 2 is delimited by a flat base 3 and lateral walls 4 which are at a right angle or oblique angle to the base 3, which, combined, surround a cavity 5 designed to receive products. The container 1 lateral walls 4 have a top edge 6, distal to the base 3, projecting from the walls 4 outwards to form an overhang and parallel with the base 3, running continuously along the entire border of the container 1.
The annular element 7 substantially has the shape of a channel-like shell with a concave interior surface 21 (see Figure 5), facing the top of the lateral walls 4 - including the edge 6 - and a convex exterior surface 8, facing the space outside the container 1.
The interior surface 21, which may be smooth or corrugated, is associated by overlapping and substantial surface mating with the top edge 6 of the lateral walls 4, also affecting, continuously along the container 1 border, a top band 22 of the walls 4, inside the container 1 receiving cavity 5.
In contrast, the exterior surface 8 is continuous and designed to constrain to it a container 1 airtight sealing barrier 9. The barrier 9 may be formed by a conventional plastic film stretched over the container 1 receiving cavity 5 and fixed to the exterior surface 8 of the annular element 7 by heat-sealing, ultrasonic sealing, gluing or other similar known technologies.
The exterior surface 8 of the shell-shaped annular element 7, facing outwards (see for example Figures 3 and 4), has a groove 10 along it, running without interruption along the top edge 6 of the container 1 and dividing the exterior surface 8 into two strips 11 and 12 on either side of the groove 10, designed to constrain, independently of one another, the airtight sealing barrier 9, which is fixed at them to the edge 6 by two seals, or by two lots of glue, parallel and independent of one another.
The double join, along the strips 11 and 12, between the barrier 9 and the container 1 edge 6 below creates not just doubling of the connections which seal the container 1 product receiving cavity 5 relative to the environment surrounding the container 1, but also help to further enhance the effectiveness of the seal, since - as is clearly shown in Figure 5 - the exterior surface 8 of the shell-shaped annular element 7, the groove 10 and the sealing barrier 9 combine to delimit a closed compartment 13, further contributing to the container 1 hermetic seal.
Considering that the inert gases normally introduced under pressure in the container 1 receiving cavity 5 to protect the products contained could in theory leak out, passing between the barrier 9 and the edge 6 and passing the first strip 11 (for example getting through at some local defect in adhesion between the connected parts), it is possible to see how the presence of the compartment 13 constitutes an expansion chamber in which any fluids which have leaked out dissipate their energy, thus no longer being able to proceed any further and to go past the second strip 12, if this too has some potential local defect in adhesion. Obviously, what was described above relative to internal gases could be repeated for those containers 1 in which the foodstuffs contained in them are protected by creating a vacuum in the compartment 3. Obviously, in this case, the only difference compared with the above would be the nature of the fluid in theory passing through (air from the surrounding environment) and the direction of the fluid flow which, in this case, would be from outside to the inside of the container 1.
As regards the shape of the groove 19, Figure 5 shows that it is preferably delimited by a local concave projection 14 in the shell-shaped annular element 7, interpenetrating the edge 6 of the container 1 which, in turn, has a matching cavity 15 for receiving the projection 14.
Due to the presence of the annular element 7 projection 14 and the cavity 15 in the edge 6 below it, interpenetrating one another, the container 1 is significantly stiffened compared with conventional containers: this allows not only achievement of a more effective hermetic seal, but also the possibility of reduced deformability under a greater weight of the contents and, or even, a greater capacity to withstand rough handling of the container 1 without excessive deformation.
When the container 1 is obtained by erecting a flat sheet of cardboard, cellulose or other similar materials in sheet form, that is to say, when it has characteristic and unavoidable corrugated surfaces due to the erecting process, placing the annular element 7 over the inner band 22 of the lateral walls 4 of the container 1 forms passages 18 along which the fluid could pass from the container 1 receiving cavity 5 to the outside or vice versa. In such a case the projection 14 at walls 16 and 17 which are opposite one another, in contact and adhering, belonging to the annular element 7 and the container 1 edge 6, creates sudden deviations in the course of the passages 18 which allow the generation of high local resistance that prevents the advance of any fluid which passes inside the passages 18.
It should be noticed that, if the annular element 7 were also obtained by erecting a flat sheet, the interior surface 21 may also be corrugated, so that, being opposite an equally corrugated surface 20 of the inner upper band 22 of the lateral walls 4, it too would contribute to the formation of the passages 18. Therefore, in that case too, the presence of the projection 14 and the cavity 15 in the edge 6 interpenetrating one another is fundamental to intercepting the passage of any fluids which may pass through the passages 18.
Clearly, the effectiveness of the airtight seal at the passages 18 may be further increased when the projection 14 is associated with the container 1 edges 6 by pressing and squeezing them together, so that the materials of which the two parts are made interpenetrate one another, further minimising the transit cross-section of the passages 18.
The effectiveness of the airtight seal is also enhanced at the passages 18 by the presence, on the edge 6 of the lateral walls 4, of another edge 19, distal and external to the projection 14, where the shell-shaped annular element 7 and the container 1 edge 6 are bent at an angle together.
The invention described fulfils the preset aims and allows low cost materials and relatively simple and economical erecting processes (container 1 erection from sheet) to be used to make containers able to provide airtight seal conditions found in much more expensive containers, produced using completely different and much more costly technologies.
The invention described has evident industrial applications and can be modified and adapted in several ways without thereby departing from the scope of the inventive concept. Moreover, all details of the invention may be substituted by technically equivalent elements.

Claims

A hermetically sealed display container (1) for perishable products, in particular foodstuffs comprising a tray (2) delimited by a base (3) and lateral walls (4) which, combined with one another, surround a cavity (5) for receiving the products, and where the lateral walls (4) have a top edge (6) which runs continuously along the container (1) border; the container (1) also comprising a shell-shaped annular element (7) which is associated by overlapping and substantial surface mating with the top edge (6) of the lateral walls (4) and which has a continuous exterior surface (8) designed to constrain to it a container (1) airtight sealing barrier (9); the container (1) being characterised in that the exterior surface (8) of the shell-shaped annular element (7), facing outwards, has at least one groove (10) along it, running without interruption along the top edge (6) of the container (1) and dividing the exterior surface (8) into at least two strips (11, 12) on either side of it, the strips being designed to constrain the airtight sealing barrier (9) independently of one another.
The container according to claim 1, characterised in that the exterior surface (8) of the shell-shaped annular element (7), the groove (10) and the sealing barrier (9) in combination with one another delimit a hermetically sealed compartment (13) for a fluid.
The container according to claim 2, characterised in that the groove (10) is delimited by a local concave projection (14) in the shell-shaped annular element (7), interpenetrating the edge (6) of the container (1).
The container according to claim 3, characterised in that the projection (14) interpenetrates a matching cavity (15) in the edge (6) of the container (1).
The container according to claim 3, or 4, or 5, characterised in that the projection (14) is made at walls (16, 17) which are opposite one another, in contact and adhering, belonging to the shell-shaped annular element (7) and the edge (6) of the container (1), the walls (16, 17) delimiting passages (18) between them, and being shaped to provide a high level of resistance to any fluid passing inside the passages (18).
The container according to claim 5, characterised in that at least one of the opposite walls (16, 17) has a corrugated surface (20) facing the other wall.
The container according to claim 6, characterised in that both of the opposite walls (16, 17) have respective corrugated surfaces (20) facing the other wall.
The container according to any of the claims from 5 to 7, characterised in that the projection (14) is associated with the edge (6) of the container (1) by pressing and squeezing one against the other and/or vice versa.
The container according to any of the foregoing claims from 5 to 9, characterised in that the edge (6) has, outside the projection (14) another distal edge (19) where the shell-shaped annular element (7) and the edge (6) of the container (1) are bent together.
The container according to any of the foregoing claims, characterised in that the container (1) is made from a sheet of material containing components selected from the cellulose family of materials.
The container according to any of the foregoing claims, characterised in that the barrier (9) comprises a plastic film which is made to adhere to the edge (6) of the container.
The container according to claim 11, characterised in that the barrier (9) is sealed to the edge (6).
The container according to claim 11, characterised in that the barrier (9) is glued to the edge (6).