FR2738226A1 - Resealable vacuum packaging for food prods. - Google Patents

Abstract

Packaging for an article (2) partic. food, that can be opened and resealed consists of an intermediate film (4), placed between a lower support sheet (1) and an upper film (3), and having a lower layer (5) of reusable self-adhesive material to fine it to the lower support sheet (1). The intermediate film also has an upper layer (6) sealing it to the upper film (3). The packaging is opened by separation of the upper film (3) from the lower layer support (1) with the intermediate film (4) staying sealed to the upper film. The self-adhesive layers allows reclosure of the packaging. Also claimed is the process of vacuum packaging consisting of previously fixing an intermediate film to the support layer with pressure sensitive adhesive layer and after insertion of the prod. sealing the covering film to the intermediate film.

Description

 The present invention relates to a packaging of at least one article, such as a food product, which can be opened and closed, as well as a vacuum packaging method.

 A package is known in which articles, in particular food products such as sausages, slices of ham, slices of meat, pieces of cheese, are placed between a lower support sheet of thermoplastic material and an upper film of covering of the products, also made of thermoplastic material, sealed in a sealed manner on the support sheet.

 Consumer access to packaged items is accomplished by manually separating the top film from the backing sheet.

 However, when only some of the products are to be consumed, the remaining products are no longer protected by the covering film since this has been at least partially removed from the support sheet, which generally leads the consumer to take out the remaining products. of the open packaging and wrap them in a protective sheet, for example of aluminum, before depositing the assembly thus packed in a place of conservation, such as a refrigerator.

 The object of the present invention is to eliminate the above drawback of known packaging by providing a packaging which, once opened, can also be closed.

 To this end, the packaging, according to 1 invention, of at least one article, such as a food product, according to which the article is placed between a lower support sheet and an upper film sealed on the lower support sheet, is characterized in that it comprises an intermediate film placed between the lower support sheet and the upper film and comprising a lower layer for fixing the intermediate film on the lower support sheet and produced from a reusable self-adhesive material, and an upper layer sealed to the upper film so that by opening the packaging by separation of the upper film from the lower support sheet, the intermediate film remains integral with the upper film and allows its self-adhesive lower layer to fix the film on the lower support sheet to close the packaging.

 The intermediate film is present in all or part of the area where the backing sheet and the upper film are sealed together.

 The intermediate film is disposed between the support sheet and the upper film only in a part of the area where the support sheet and the upper film are sealed together.

 The part of the aforementioned sealing zone where the intermediate film is present is an internal part delimited by the external edge part of the packaging where the support sheet and the upper film are directly sealed together without an intermediate film between them.

 Preferably, the intermediate film is a label.

 According to a preferred embodiment, the lower support sheet is a tray, preferably thermoformed, and the upper film covers the product with application of vacuum all around the product and the intermediate film is fixed by its lower self-adhesive layer at the bottom of the support plate or along at least one lateral edge thereof.

 The intermediate film is preferably fixed to the support plate by extending along three sides of this support plate.

 According to another embodiment, the lower support sheet is in the form of a tray having a peripheral rim all around its access opening and the upper film constitutes the closing cover of the heat-sealed tray on the peripheral rim thereof. and the intermediate film is fixed by its self-adhesive layer on at least part of the internal edge of the peripheral rim with a corresponding internal edge part of the heat-sealed closure cover on the upper layer of the intermediate film.

 The upper film and the lower support sheet of the packaging, made of a thermoplastic material, are sealed together so as to be easily separated from each other when the packaging is opened manually and the upper layer of the intermediate film is made of a suitable plastic material compatible, for its sealing, with the composition of the upper film or of the internal sealing layer forming the contact surface of the upper film.

 For example, in the case where the aforementioned internal sealing layer of the upper film is made of a material chosen from the group comprising an ionomer resin, a high density polyethylene and a low density polyethylene, the upper layer of the intermediate film may be based on polyethylene.

 According to an alternative embodiment, the upper layer of the intermediate film is sealed to the upper film by an adhesive spread over the upper layer of the intermediate film.

 When, according to a preferred aspect of the invention, the intermediate film is a label, this includes information visible to a buyer through the transparent upper film, relating for example to the composition of the product, on behalf of the manufacturer of that -this, and printed either on a layer fixed between the upper and lower layers of the label, or on the upper layer of the label.

 The invention also provides a method of vacuum packaging, comprising the steps of placing at least one article, such as a food product, on a lower support sheet; cover the article with a thermo-softened top covering film; and sealing the covering film to the support sheet with the application of vacuum all around the article and between the support sheet and the covering film, and which is characterized in that it consists, before application vacuum around the article, fixing an intermediate film, preferably constituting a label, on the support sheet by means of a lower layer of pressure-sensitive adhesive of the intermediate film and sealing an upper layer from the intermediate film to the covering film when the covering film is brought into contact with the product and the support sheet so that the intermediate film is permanently integral with the covering film.

The invention will be better understood and other aims, characteristics, details and advantages thereof will appear more clearly in the explanatory description which follows, given with reference to the appended schematic drawings given solely by way of example illustrating two embodiments of the invention and in which
- Figure 1 is a top view of a vacuum package according to a preferred embodiment of the invention;
- Figure 2 is an enlarged sectional view along line II-II of Figure 1;
- Figure 3 is a perspective view showing the packaging of Figure 1 in the open position; and
- Figures 4 and 5 are cross-sectional views of a package according to another embodiment of the invention.

 The invention will first be described with reference to vacuum packaging, in particular of food products, but it is understood that it also applies to any other type of packaging as will be seen later.

 The vacuum packaging to which the invention preferably applies is of the type comprising, as shown in FIGS. 1 to 3, a support sheet 1 for food products 2, such as in this case slices of ham, and which is preferably a thermoformed tray with inclined side walls 1a and an upper film 3 intimately covering the food products 2 and sealed to the support sheet 1 with the application of vacuum around the products 2 and between the support sheet 1 and the covering film 3.

 The process for producing the vacuum packaging as defined above is widely known and is described, for example, in British patents NO 1,307,054 and 1,404,417.

 In general, according to this known method, at least one article, such as a food product, is placed on a support sheet in the form of a tray and a plastic film, intended to cover the article, is brought into contact by suction with a heated mold cavity to both partially deform the plastic film and heat it by conduction. Then, the space between the plastic film and the support sheet is subjected to a vacuum and the suction applied to the walls of the mold cavity is released so that the plastic sheet is brought into contact with the article and the backing sheet to form a waterproof package.

 In this type of known vacuum packaging, the cover film and the thermoplastic support sheet are sealed together so as to allow the package to be easily opened by manually separating the cover film from the support sheet while guaranteeing the integrity of the packaging during handling and storage thereof. To allow easy opening of the vacuum packaging, the upper film and / or the support sheet may respectively have on their contact surfaces two sealing layers, the composition of which is chosen to allow the covering film to be easily detached. of the backing sheet. Examples of compositions of such sealing layers are described, for example, in European patent application NOO 595 442.

 According to the invention, the vacuum packaging of FIG. 1 also comprises an intermediate film 4 disposed between the support plate 1 and the covering film 3 so that by opening the packaging to access the food products 2, the intermediate film 4 remains integral with the underside of the covering film 3, to then allow the covering film 3 to be fixed on the support plate 1 and thus close the packaging after having removed from it some of the food products.

 To this end, the intermediate film 4 comprises a lower layer 5 for fixing the film 4 to the support plate 1 and which is made from a reusable self-adhesive material or pressure-sensitive adhesive, known per se, and a layer upper 6 made of a plastic material sealed to the lower face of the covering film 3.

 The intermediate film 4, preferably, does not cover the products 2, that is to say that the intermediate film 4 is present between the support plate 1 and the covering film 3 in all or part of the area where the support plate 1 and cover film 3 are sealed together. Preferably, the intermediate film 4 is disposed between the sheet 1 and the film 3 only of this part of the sealing zone which is also preferably an internal part delimited by the external edge part of the packaging where the tray support 1 and the covering film 3 are directly sealed together without an intermediate film 4 between them.

 Preferably, the intermediate film 4 is a label carrying information visible through the covering film 3 and relating for example to the composition of the food products 2, in the name of these products, in the name of the manufacturer, etc. Preferably, the label 4 is fixed by its lower self-adhesive layer 5 to the bottom of the support plate 1, extending along three of the sides of this plate, thus having a substantially U-shaped configuration, the base of which 4a, wider than the sides 4b, carries the above information of interest to the buyer. In addition, the sides 4b of the U can have a length such that by partially separating the covering film 3 from the support plate 1 as shown in Figure 3 to access some of the food products 2, closing the packaging by folding the cover film 3 on the support plate 1 and exerting pressure on the sides of the cover film 3, the label 4 prevents the passage of air between the covering film 3 and the support plate 1, towards the remaining products 2.

 According to an alternative embodiment, in the case of using a support plate 1 receiving over practically its entire extent food products, the label 4 can be fixed on all or part of the inclined lateral edges 1a of this plate.

 Of course, other configurations and locations of the label 4 are possible without departing from the scope of the present invention. Thus, the label 4 may be positioned on the support plate 1 at the part of the covering film 2 which comes off first of the support plate 1 when the packaging is opened and the label may be rectangular, round, or any other shape.

 The label 4 can also include an intermediate layer 7 made for example of paper or plastic, placed between the lower 5 and upper 6 layers thereof and on which the information of interest to the buyer is printed. According to a variant, this information can also be printed on the upper layer 6 of the label 4. One could provide, if necessary, other layers (not shown) intended for example to bond together the different layers 5, 6, 7 to each other from label 4.

 The plastic material of the upper layer 6 of the label 4 which must be sealed with the covering film 3 is chosen so as to be compatible for this purpose with the composition of the covering film 3, preferably of the internal sealing layer. of this film and of which examples of composition are mentioned in the European patent application NOO 595 442 previously cited. Thus, when the internal sealing layer of the covering film 3 is an ionomer resin, a high density polyethylene or a low density polyethylene, plastics based on polyethylene can be used for the upper layer 6 of the label 4. According to variant embodiments, ionomer resins or a copolymer of ethylene and vinyl acetate (EVA) can also be used as upper layer 6 of the label 4.

 The opening of the vacuum packaging of FIG. 1 can also be facilitated by providing, as is known per se, a non-heat-sealed corner of the packaging which forms a tab of the covering film which can be grasped and pulled to begin with. the opening of the packaging or, as shown in FIG. 1, a precut corner 1b of the support plate 1 which is sealed to the covering film 3 and which, once detached from the rest of the support plate 1 by folding it upwards and / or down along the precut, is gripped and pulled with the covering film 3 to open the package.

 The process for producing the vacuum packaging according to the invention can be summarized as follows.

 The label 4 is fixed to the support plate 1 by its lower self-adhesive layer 5 before or after the food products to be packaged are placed on this plate, in any case before the application of vacuum around these food products. Then, the label 4 is sealed by its upper layer 6 to the covering film 3 when the covering film 3 is brought into contact with the products and the support plate 1 so that the label 4 is permanently secured to the covering film 3. The sealing of the label 4 to the covering film 3 can be carried out, as explained above, by providing an upper layer 6 of the label 4 compatible with the material of the covering film 3 or the internal sealing layer thereof. For example, it is possible to provide an upper layer 6 of the label 4 made of polyethylene and a covering film 3 of the same material so that, when sufficiently heated, the film 3 and the label 4 are sealed together, when the film 3 is brought into contact with the support plate 1. According to an alternative embodiment, it is also possible to provide a bonding layer spread over the upper layer 6 of the 'ethics head 4 and which is activated when the thermo-softened covering film 3 is brought into contact on the support plate 1.

 Figures 4 and 5 show the application of the invention to the known type of packaging in which a tray 8 produced by thermoforming and receiving article 2, such as at least one food product, is closed by a film 9 forming a heat-sealed cover on a peripheral rim 10 around the access opening of the tray 8. In this case, the self-adhesive label 4 is fixed to at least part of the internal edge of the peripheral rim 10 of the tray 8 by its inner layer 5 with the upper layer 6 of the label 4 heat-sealed to a corresponding inner edge portion of the closure cover 9. Preferably, and as in the embodiment described above, the compositions of the layers internal sealing respectively of the cover 9 and the peripheral rim 10 are chosen to allow easy opening of the packaging (see for example the two US patents Nos. 4,665,130 and 4,666,778 in the name of Shell) and a means such as a free tab at a corner of the cover 9 or a precut corner of the peripheral rim 10, may be provided.

When the cover 9 is at least partially separated from the peripheral rim 10 of the tray 8, the label 4 remains sealed to the cover 9 and by folding the raised part of the cover 9 over the corresponding part of the peripheral rim 10 of the tray 8 and exerting pressing the label, the packaging can be easily closed.

 The process for producing the packaging of FIG. 5 is as follows.

 First of all, the tray 8 is preformed or formed in line by thermoforming, then the label 4 is bonded by its lower layer 5 along at least part of the internal upper edge of the peripheral rim 10. The film 9 is then placed on the tray 8 containing the item or items 2 to be packaged with, if necessary, applying vacuum to the chamber defined between the film 9 and the tray 8. Finally, the film 9 is sealed at the peripheral rim 10 by means of a heat-sealing plate 11 with concomitant heat-sealing from the label 4 to the film 9 forming a cover. A modified atmosphere may be injected into the packaging before closing it.

 As shown in FIGS. 4 and 5, the label 4 can be fixed on at least part of a peripheral shoulder 12 constituting the internal edge of the rim 10 and having a small height corresponding substantially to the thickness of the label 4 so that after heat-sealing the film 9 on the peripheral edge 10 of the tray 8, the heat-sealing zone covering the label 4 and the edge 10 is substantially flat.

 Once the packaging of Figure 5 open, it can be closed by the label 4 which is fixed by its self-adhesive lower layer 5 on the peripheral shoulder 12 to prevent contamination of the product or products remaining in the tray 8 although air will in any case be in contact with the remaining product or products.

Claims (13)

 1. Package of at least one article (2), such as a food product, which can be opened and closed, according to which the article (2) is placed between a lower support sheet (1) and an upper film (3) sealed on the lower support sheet (1), characterized in that it comprises an intermediate film (4) disposed between the lower support sheet (1) and the upper film (3) and comprising a lower layer (5) of fixing of the intermediate film (4) on the lower support sheet (1) and produced on the basis of a reusable self-adhesive material, and an upper layer (6) sealed to the upper film (3) so that by opening the packaging by separation of the upper film (3) from the lower support sheet (1), the intermediate film (4) remains integral with the upper film (3) and allows its self-adhesive lower layer (5) to fix the film upper (3) on the lower support sheet (1) to close the packaging.  2. Packaging according to claim 1, characterized in that the intermediate film (4) is present in all or part of the area where the support sheet (1) and the upper film (3) are sealed together.  3. Packaging according to claim 1 or 2, characterized in that the intermediate film (4) is disposed between the support sheet (1) and the upper film (3) only in a part of the area where the support sheet ( 1) and the upper film (3) are sealed together.  4. Packaging according to claim 3, characterized in that the part of the aforementioned sealing zone where the intermediate film is present (4) is an internal part delimited by the external edge part of the packaging where the support sheet ( 1) and the upper film (3) are directly sealed together without an intermediate film (4) between them.  5. Packaging according to one of the preceding claims, characterized in that the aforementioned intermediate film is a label (4).  6. Packaging according to one of the preceding claims, characterized in that the lower support sheet (1) is a tray, preferably thermoformed, and the upper film (3) covers the product (2) with application of vacuum all around of the product (2) and in that the intermediate film (4) is fixed by its self-adhesive lower layer (5) to the bottom of the support plate (1) or along at least one lateral edge thereof.  7. Packaging according to claim 6, characterized in that the intermediate film (4) is fixed to the bottom of the support plate (1) extending along three of the sides of this plate (1).  8. Packaging according to one of claims 1 to 5, characterized in that the lower support sheet (1) is in the form of a tray (8) having a peripheral rim (10) all around its access opening and the upper film (3) constitutes the cover (9) for closing the tray (8) heat-sealed on the peripheral rim (10) thereof and in that the intermediate film (4) is fixed by its self-adhesive layer ( 5) on at least part of the internal edge of the peripheral rim (10) with a corresponding internal edge part of the closure cover (9) heat-sealed on the upper layer of the intermediate film (4).  9. Packaging according to one of the preceding claims, characterized in that the upper film (3) and the lower support sheet (1), made of a thermoplastic material, are sealed together so as to be easily separated from one the other during manual opening of the packaging and the upper layer (6) of the intermediate film (4) is made of a suitable plastic material compatible for its sealing with the composition of the upper film (3) or of the layer of internal seal forming contact surface of the upper film (3).  10. Packaging according to claim 9, characterized in that in the case where the aforementioned internal sealing layer of the upper film (3) is made of a material chosen from the group comprising an ionomer resin, a high density polyethylene and a low density polyethylene , the upper layer (6) of the intermediate film (4) is based on polyethylene.  11. Packaging according to one of claims 1 to 8, characterized in that the upper layer (6) of the intermediate film (4) is sealed to the upper film (3) by an adhesive spread on the upper layer (6) of the film intermediate (4).  12. Packaging according to one of claims 5 to 11, characterized in that the aforementioned label (4) also includes information visible to a buyer through the transparent upper film (3), for example relating to the composition of the product (2), on behalf of the manufacturer of the product, and printed either on a layer (7) fixed between the upper (6) and lower (5) layers of the label (4), or on the upper layer (6) of the label (4).  13. A vacuum packaging method, comprising the steps of placing at least one article (2), such as a food product, on a lower support sheet (1); cover the article (2) with an upper thermo-softened covering film (3); and seal the covering film (3) to the support sheet (1) with the application of vacuum all around the article and between the support sheet (1) and the covering film (3), characterized in that it consists, before applying vacuum around the article, to fix an intermediate film (4), preferably constituting a label, on the support sheet (1) by means of a lower layer d pressure sensitive adhesive (5) of the intermediate film (4) and sealing an upper layer (6) of the intermediate film (4) to the covering film (3) when the covering film (3) is brought into contact with the product (2) and the support sheet (1), so that the intermediate film (4) is permanently integral with the covering film (3).