EP1077187B1 - Fluid-tight and absorbing foil for forming a part of a container - Google Patents

Description

Many products sold on store shelves (especially free service) have high humidity and when packaged in containers leak-proof, exudates spread over the bottom of the container and the products soak constantly in these liquids, which is a defect that we try to avoid.

When the container is transparent, customers see these liquids which give the packaged product an unattractive appearance, likely to prevent the act of purchase.

To avoid these drawbacks, we have already thought of placing in the container a material absorbent. So, for example, fresh meats, especially red meats and whole poultry, are placed in rigid or semi-rigid trays made of synthetic which contain an absorbent pad or even a layer of product absorbent such as cellulose wadding.

After placing the product in the tray, a waterproof, stretchable and transparent film wraps the product as closely as possible and is fixed under the tray. One or more labels are glued to the film for customer information (weight, price per kilo, etc.) and everything is shelved, allowing customers to freely manipulate each set to make their choice, without the internal fluids due to exudates spilling unfortunately, thus preserving the product from any bloody trace around the product.

Another known packaging comprises a more or less hollow semi-rigid base in synthetic material (eg crystal polystyrene) and also a hollow shell semi-rigid which covers the product and is fixed by snap-fastening on a rim of the base. This packaging is well suited to pastries because the shell practically does not touch not the product and does not crush its fragile parts such as whipped cream, fruit or decor. A label is then stuck on the hull for the information of the customer.

These measures taken to absorb moisture and exudates are not fully satisfactory because a tampon takes on the color of the generally reddish exudate and the layer of absorbent product sticks easily to the product and requires, when unpacking, a take off in rather unpleasant fragments.

In one case as in the other, it is a reported item whose implementation requires an additional handling operation during packaging. But the lengthening of the period leading to the expiry date led to some professionals to suggest other processes by which the product is stored under modified atmosphere whereas with stretch films or snapped shells the product is in the ambient atmosphere since there is no real seal created between the interior of the container and the outside atmosphere.

• le produit décrit dans EP 0 295 943 et qui consiste en un coussinet formé de plusieurs couches fixées les unes aux autres selon des lignes longitudinales et transversales pour constituer une marge 9 au format et à la forme voulue pour le coussinet. Celui-ci doit ensuite être placé dans une contenant.
• le produit décrit dans WO 99 32286 qui est une barquette thermoformée, et la forme représentée sur la figure 3 montre que cette barquette ne peut pas être operculée car elle ne présente aucun rebord supérieur plan. La très faible profondeur de la barquette s'explique par le fait qu'elle est destinée à être enveloppée après avoir reçu le produit à emballer, tel qu'une poulet.

We also know:

• the product described in EP 0 295 943 and which consists of a pad formed of several layers fixed to each other along longitudinal and transverse lines to form a margin 9 in the format and shape desired for the pad. This must then be placed in a container.
• the product described in WO 99 32286 which is a thermoformed container, and the shape shown in FIG. 3 shows that this container cannot be sealed because it has no planar upper rim. The very shallow depth of the tray is explained by the fact that it is intended to be wrapped after having received the product to be packaged, such as a chicken.

So, the need for sealing leads to providing trays and laminated bases to ensure gas tightness of their bottom. The sealing is obtained by a waterproof film also fixed tightly to the tray or base, so that the neutral gas, generally nitrogen, which constitutes the interior atmosphere of the whole, correctly confined whatever the constraints that this set undergoes during handling of transport, storage and presence on the shelves.

This structure does not allow adding an absorbent layer before closing and it is therefore incompatible with the absorption of exudates.

The present invention provides a new solution which makes it possible to obtain both a sealed container structure and comprising absorption means. We thus obtain a set with extended shelf life thanks to the presence of an atmosphere modified, and an absence of free and visible exudates.

To this end, the subject of the invention is a sheet of synthetic material stored in a reel of very long, for the containment of wet products, especially food, characterized in that it consists of a complex formed of at least three layers called respectively "exterior", "interior" and "intermediate", the layer outer layer being liquid-tight, the inner layer being both permeable to liquids and moisture and weldable type, the intermediate layer between the two previous layers being made of an absorbent material intended to retain liquids from the contained and likely to reach it through the permeable inner layer.

• on assemble une couche dite « extérieure » de grande longueur étanche aux liquides et une couche dite « intermédiaire » de grande longueur constituée par un matériau absorbant,
• on assemble la couche intermédiaire de grande longueur et une couche dite « intérieure » de grande longueur qui est à la fois perméable aux liquides et à l'humidité et de type soudable,
• on enroule la feuille multicouche ainsi obtenue pour constituer une bobine.

The invention also relates to a method for the use of a sheet of synthetic material constituted by a complex formed of a multilayer sheet stored in a reel, for the manufacture of a container constituted wholly or in part by said multilayer sheet, container intended for the confinement of a wet product, in particular a food product, characterized in that, with a view to obtaining the multilayer sheet:

• a so-called “outer” layer of great length impermeable to liquids is assembled and a so-called “intermediate” layer of great length consisting of an absorbent material,
• the intermediate length layer is assembled with a so-called “interior” layer of great length which is both permeable to liquids and to moisture and of the weldable type,
• the multilayer sheet thus obtained is wound up to constitute a coil.

La figure 1 est une vue schématique montrant une feuille de grande longueur conforme à l'invention, en partie déroulée d'une bobine.

La figure 2 est une vue schématique en coupe de la feuille de la figure 1.

Les figures 3 et 4 sont des vues schématiques montrant un contenant conforme à l'invention comprenant une coque semi-rigide préformée et un opercule réalisé avec une feuille issue de la bobine de la figure 1, lors du conditionnement d'un poulet.

La figure 5 est une vue schématique montrant l'ensemble du contenant et du contenu prêt à sa mise en place sur un rayon de magasin.

La figure 6 est une vue schématique montrant une feuille de grande longueur conforme à l'invention, en partie déroulée d'une bobine, selon un mode de réalisation particulier.

La figure 7 est une vue schématique en coupe de la feuille de la figure 6.

La figure 8 est une vue schématique analogue à celle de la figure 7, mais à une plus grande échelle afin de rendre plus visibles les perforations de la couche intérieure et de la couche intermédiaire absorbante.

La figure 9 est une vue schématique montrant un contenant conforme à l'invention, comprenant un socle thermoformé dans la feuille des figures 6 à 8 ainsi qu'une cloche semi-rigide.

La figure 10 est une vue schématique montrant l'ensemble du contenant et du contenu prêt à sa mise en place sur un rayon de magasin.

The invention will be better understood from the detailed description below made with reference to the accompanying drawing. Of course, the description and the drawing are given only by way of an indicative and nonlimiting example.

Figure 1 is a schematic view showing a very long sheet according to the invention, partly unwound from a coil.

Figure 2 is a schematic sectional view of the sheet of Figure 1.

Figures 3 and 4 are schematic views showing a container according to the invention comprising a pre-formed semi-rigid shell and a cover made with a sheet from the coil of Figure 1, during the packaging of a chicken.

Figure 5 is a schematic view showing the entire container and the contents ready for its installation on a store shelf.

Figure 6 is a schematic view showing a very long sheet according to the invention, partly unwound from a coil, according to a particular embodiment.

FIG. 7 is a schematic sectional view of the sheet of FIG. 6.

Figure 8 is a schematic view similar to that of Figure 7, but on a larger scale in order to make more visible the perforations of the inner layer and the absorbent intermediate layer.

Figure 9 is a schematic view showing a container according to the invention, comprising a thermoformed base in the sheet of Figures 6 to 8 and a semi-rigid bell.

Figure 10 is a schematic view showing the entire container and the contents ready for its installation on a store shelf.

Referring to Figures 1 and 2, we see a very long sheet 1 conforming to the invention and we also see that this sheet 1 is stored, transported and used in the form of a coil 2.

The sheet 1 is formed of three layers respectively outer 3, intermediate 4 and interior 5 assembled to each other.

Layers 3 and 5 are called "exterior" and "interior" by reference to their location on the finished container, as will be explained later.

The outer layer 3 is impermeable at least to liquids and possibly to gases. She is advantageously monomaterial but it can also be itself formed by the association of at least two layers (one of which, in particular, may be a layer fence).

This layer 3 is, for example, a 12 micron film of polyethylene terephthalate Metallic.

The intermediate layer 4 is an absorbent layer such as a nonwoven formed of fibers blended of polyester and cellulose, having a specific weight of 45 grams per square meter. The invention is illustrated here by the packaging of a piece of meat (Figures 3 to 5), layer 4 must be suitable for food contact.

The inner layer 5 being intended to be in direct contact with the products to be packaged, it must also have food quality. It must both be permeable to liquids and of the weldable type, that is to say capable of being welded to itself or to another part made of synthetic material.

Here, we have represented the case where layer 5 is made permeable by multiples microperforations 6. This layer can be of polyethylene of the so-called "universal" type. because of its ability to weld on any synthetic material, having a thickness of around 55 microns.

The microperforations 6 are regularly arranged, equidistant from the order of 6 millimeters.

The sheet 1 can be used in all cases where a waterproof packaging is desired and simultaneously absorbent, i.e. when the products to be packaged are likely to create exudates or condensation liquids. Indeed, the tightness is given by the outer layer 3, the absorption capacity is given by the intermediate layer 4 and the weldability by the inner layer 5, the liquids coming from the products being absorbed by the fact that the inner layer 5 lets them pass to layer 4 through the perforations 6.

Such a sheet 1 can be used alone to directly wrap products.

It may be a packaging prior to shelving, in which case the products are placed on the inner layer 5, then the latter is welded to itself to confine products tightly.

It may also be the packaging consecutive to the choice of so-called "cut" products, for example a customer: meat, cheese, etc. The seller places the products on layer 5 of the sheet 1, fold it in half over the products and using an electrode heating, performs the watertight closure of the assembly by welding to itself of the layer 5.

These two conditioning methods are well known in themselves and do not require no further details.

The invention therefore makes it possible to produce containers, or envelopes, by the only means of sheet 1.

However, the invention also applies to the sealing of hollow parts such as trays, which is shown in Figures 3 to 5.

A product, here a piece of meat A, is placed directly in a tray 10 in rigid or semi-rigid synthetic material, of a type known per se, having a rim peripheral plane 11 (figure 3). Then the sheet 1 is placed above the tray 10 taking care that the layer 5 is turned towards the inside of said tray 10, it is applied to the rim 11 and welded to the latter by the inner layer 5 (Figure 4).

Then the entire container 1-10 and content A is turned over so that the piece of meat A rests not on the bottom of the tray 10 but on the layer 5 of the sheet 1 (figure 5).

Meat exudates pass through microperforations 6 and reach the layer absorbent intermediate 4 which retains and hides them from the view of customers.

We understand that these exudates have the possibility of migrating outside and oozing on the edges of sheet 1, especially if layer 4 is saturated.

This defect would be disqualifying and the invention provides for its disappearance by exerting a strong pressure of the welding electrodes on the outermost margin of the sheet 1, on the rim 11 of the tray 10, which is shown, obviously very schematic, in FIG. 4 in the form of flats 7 which are more visible in FIG. 5.

We see that we crush the intermediate layer 4 along the entire periphery of the rim 11 and this completely closes the clean cut of the edges of the sheet 1, causing the welding of the waterproof outer layer 3 to the inner layer 5 which is no longer permeable to the place of its weld due to the disappearance of microperforations 6 due creep of the softened material.

Note that at the time of this welding, the material constituting the inner layer 5 also flows through the fibers of the absorbent layer 4 and thus makes the sheet 1 waterproof in the welding (or sealing) area.

When making sheet 1, we assemble layers 3 and 4 along their entire surface and layers 4 and 5 are assembled according to zones which, here, are thin strips 8 of glue known in the industry as "hot melt" (Figure 2). In this way, we obtain a unitary sheet, without completely sealing microperforations 6, which keeps the layer 5 its essential permeability.

Referring now to Figures 6 to 8, we see another embodiment of the invention that the outer layer 30 is thicker, for example amorphous polypropylene terephthalate of 300 microns, only in the applications described previously, so that it can be thermoformed and have the rigidity of a stable form.

In these figures 6 to 8, the same elements have the same references as on the Figures 1 to 5 and these elements will therefore not be described again.

The absorbent layer 40 is crossed by microperfbrations 41 located opposite the microperforations 6 of the inner layer 5 (for example oriented polypropylene), this which can be obtained by creating microperforations 6 and 41 in one and the same operation, after combining layers 40 and 5.

The perforations 6 and 41 are arranged in a regular manner, equidistant from a distance on the order of 3 millimeters.

Sheet 1 therefore comprises the three essential layers, namely the inner layer 5 permeable (here thanks to microperforations 6), the absorbent intermediate layer 40 and the outer layer 30.

This sheet, or complex, 1 is thermoformed and here takes the form of a tray 50 surrounded by a raised edge 51 and a flange 52 forming a base.

The products to be packaged, here a cake B, are placed on the tray 50, namely directly on the permeable layer 5. Next, a cover 60 is put in place having a bell-shaped upper part 61 and a skirted edge 62 whose inclination is the same as that of the edge 51, so that the edge 62 of the cover 60 applies exactly on the edge 51 of the plate 50.

They are fixed to each other by any known means: light bonding, staples, etc.

Of course, one can also use a mechanical snap allowing both the correct retention of the cover 60 on the plate 50 and its easy removal, without tools or delicate handling.

It is understood that here again the exudates and other liquids from the products are absorbed by the intermediate layer 40 and this all the more effectively as it is itself perforated to increase the capillary effect which is hers. The seal between the inside, namely the top of the tray 50 surmounted by the cover 60, and the outside is provided by layer 30.

The packaging of a cake has been described with reference to FIGS. 9 and 10 but it goes without saying that the same principle can be adopted for all kinds of other products, including cheeses presented for sale on a tray and covered, protected by a bell.

The thermoforming of sheet 1 has so many possible applications that the invention has countless opportunities for adaptation.

The above description, which cannot be exhaustive, shows that the invention allows different embodiments, the main ones of which have been described, which are themselves susceptible of variants of all kinds: exclusive and direct use of the large sheet length, sealing (or closure) of any container, thermoforming and association possible with an additional element: cover, bell, etc.

Claims (20)

1. Long sheet of synthetic material stored on a reel, for the purpose of confining moist products, especially food products, characterized in that it consists of a complex (1) formed from at least three layers called the "outer" layer (3-30), the "inner" layer (5) and the "intermediate" layer (4) respectively, the outer layer (3-30) being impermeable to liquids, the inner layer (5) being both permeable to liquids and to moisture and of the weldable type, the intermediate layer (4-40) held between the above two layers (3-30 and 5) being made of an absorbent material intended to retain the liquids that come from the contents (A, B) and are likely to reach it through the permeable inner layer (5).
2. Sheet according to Claim 1, characterized in that the liquid-impermeable outer layer (30) is thicker than the intermediate layer (5) and the inner layer (40) and is of the thermoformable type so as to be able to constitute a rigid or semi-rigid container part, such as a tray (50), a base or the like, to which part a rigid or semi-rigid hollow part, such as a cover (60), a bell, a shell or the like is fixed by advantageously removable means, such as an elastic mechanical fastener.
3. Sheet according to Claim 1, characterized in that the outer layer (3-30) is made of a single material.
4. Sheet according to Claim 1, characterized in that the outer layer (3) is made of a metallized synthetic material.
5. Sheet according to Claim 1, characterized in that the intermediate layer (4-40) is made of a non-woven material.
6. Sheet according to Claim 5, characterized in that the intermediate layer (4-40) is formed by a mixture of polyester and cellulose fibres.
7. Sheet according to Claim 1, characterized in that the intermediate layer (40) is penetrated by many perforations (41).
8. Sheet according to Claim 7, characterized in that the perforations (41) are equidistant.
9. Sheet according to Claim 1, characterized in that the inner layer (5) is penetrated by many perforations (6).
10. Sheet according to Claim 8, characterized in that the perforations (6) are equidistant.
11. Sheet according to Claims 7 and 9 above, characterized in that the intermediate layer (40) and the inner layer (5) are both penetrated by many perforations (41 and 6) located so as to face one another.
12. Sheet according to Claim 1, characterized in that the outer layer (3-30) and the intermediate layer (4-40) are fixed to each other.
13. Sheet according to Claim 12, characterized in that the outer layer (3-30) and the intermediate layer (4-40) are fixed to each other over their entire area
14. Sheet according to Claim 1, characterized in that the inner layer (5) and the intermediate layer (4-40) are fixed to each other by regions (8).
15. Method of using a sheet of synthetic material consisting of a complex formed by a multilayer sheet stored on a reel, for the purpose of manufacturing a container consisting entirely or partly of the said multilayer sheet, which container is intended for confining a moist product, especially a food product, characterized in that, for the purpose of obtaining the multilayer sheet:

    a long liquid-impermeable "outer" layer (3-30) and a long "intermediate" layer (4-40) that consists of an absorbent material are joined together;

    the long intermediate layer (4-40) and a long "inner" layer (5), which is both permeable to liquids and to moisture, and of the weldable type, are joined together; and

    the multilayer sheet (1) thus obtained is wound up in order to constitute a reel (2).
16. Method according to Claim 15 for the use of a multilayer sheec stored on a reel, characterized in that, for the purpose of obtaining a container, portions of the multilayer sheet (1) are extracted from the reel (2), each portion having to contribute, entirely or partly, to the construction of the said container for confining moist products (A), especially food products.
17. Method according to Claim 15, characterized in that each portion of multilayer sheet (1) extracted from the reel (2) is folded over onto itself and sealed by welding in order to form a bag, a sachet, an envelope or the like.
18. Method according to Claim 15, characterized in that each portion of multilayer sheet (1) extracted from the reel (2) is applied opposite a hollow part (10) and it is fixed to the said hollow part (10) by welding along its edges (11) so as to constitute a complete container, provided with its contents (A) and thus covered by the said portion extracted from the reel 1 (2).
19. Method according to Claim 15, characterized in that, to manufacture the multilayer sheet (1), a synthetic material of the thermoformable and liquid-impermeable type is chosen for the outer layer (30), this layer being thicker than the intermediate layer (5) and the inner layer (40).
20. Method according to Claim 19, characterized in that the portions of multilayer sheet (1) that are extracted from the reel (2) are hot-formed so as to constitute at least part of a rigid or semi-rigid container contributing to the confinement, namely an outer wall such as a base (50), a tray or the like.

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