MXPA98005359A - Use of a stretchable and removable film for the packaging protector of exhibic containers - Google Patents

Abstract

The present invention relates to a method for packaging and sealing under vacuum a food product display container by means of a water insoluble stretch film, the above film is thermally welded to the package, the method is characterized in that the film is stretchable and Water soluble is used which has a front side and a reverse side turned towards the container, the stretched film mentioned above is printed on the side on the reverse side and complexed by means of an adhesive to a welding support and where the support In the form of film complexes, it is welded on the container in order to obtain a detached film.

Description

USE OF A STRETCHABLE AND REMOVABLE FILM FOR THE PROTECTIVE PACKAGING OF DISPLAY CONTAINERS DESCRIPTION OF THE INVENTION This invention relates to a method for implementing protective packaging and vacuum packaging of a display container of a noble product, in particular a high-quality food product, by means of a film that can be stretched and peeled off. It is also related to a packaging film that can be stretched and detached, which has the characteristic of being printed or intended to be prey in various colors by flexography or by multicolor eliography, particularly in trichromy or quadricrophy, as well as the use, in the packaging field with thin layer, of a film that can be stretched and peeled for the purpose of implementing the protective packaging and the vacuum packaging of the display container of a high-quality product, in particular a food product. The sale of food products in large stores requires very high quality decorative packaging, which convincingly shows the value and freshness of the products. Generally, the products are presented elegantly in a tray or on a tray. Then they are covered with a highly transparent top film which wraps the product as a second thin layer. A printed self-adhesive label is placed on this film, the object of which is to convey a promotional message illustrated or described. It shows a minimum of mandatory information such as weight, ingredients, bar code and date of sale. They are suitable for products in the upper part of the series, such as selected pieces of meat, slices of smoked ham, pates or fish fillets or game meat. The films of plastic material used must have certain thermal and mechanical properties and meet the following requirements: good impermeability to gases and water vapor in order to ensure a prolonged preservation; easy opening of the weld regardless of the requirement of great impermeability of the weld; prestigious presentation; high brightness; - condition of the surface that allows the adherence of printed self-adhesive labels, and high thermal stability. From US-A-3912823 a stretched and printed PET film is known. However, this film is not complex for a support by welding by means of an adhesive. In US 3912823, at the time of the welding of the lower PET film "1" to the upper PET film "2", the upper film is not of the peelable type. In fact, in the packaging according to US-A-3912823, the lower and upper films must belong to the same family in order to allow them to be welded to each other. The welding obtained between the previous films is permanent, in other words it is not detachable. The opening of the package consisting of welded PET requires the use of a cutting object. From EP-A-0328245, it is known to use coextruded thin film films made of breakable polyethylene and barrier films used as display containers for meat and other food products. These co-extruded films, due to their elastic structure, can perfectly surround the contours of the products to be packed without showing the slightest undulation. They form an effective barrier against gases. Due to its high elasticity, combined with its manufacturing process as well as the nature of the resins used, these materials do not have the necessary and sufficient characteristics to be printed because, for example, multicolored trichrome or quadrichrome heliographic printing requires the use of a support that can be printed that has good dimensional stability in the printing machine. The dimensional stability allows a perfect definition of the different -colors and the constancy of the mechanical step imposed by the packing machine, which is obtained during printing. Consequently, the supports manufactured by co-extrusion and used up to now in applications of "thin layer" due to their great extension capacity, are not suitable for the heliographic printing described above. In addition, the support of the printing step in the packaging machine is very random. It should also be noted that these films can only be printed on the surface, which greatly diminishes their brilliance, as well as the ability to sell the product. It should also be noted the difficulty of making printing inks that adhere properly to it. Due to this, there is a need to use printed self-adhesive labels to be placed on the support in order to make it more commercially attractive and to mention in it the information required by law requires the end user to invest in their production lines in automatic labeling machines which involves a considerable increase in the work and affects the production speeds, especially through the interruptions, when changing the reel of labels.

Now, in the field of thin layers, the demand for materials which can be printed in multicolored heliography, in particular trichrome and quadrichrome, is very high. Furthermore, from the patent WO 95/21105 it is known to use a film, oriented, or extruded or co-extruded in some other way, made of PVA (polyvinyl alcohol), a thin-film material for packaging non-food products. The document describes that certain components are soluble in water and shows the use of a porous lower support and, due to this, not impervious to gases. Therefore, it can be considered that such a system is not capable of preserving food products which have a shelf life of 21 to 90 days and this at very high levels of environmental humidity and storage temperatures ranging from 4 to 7 ° C . Of course, the fact that this material is soluble in water at a temperature of 40 to 100 ° C, and preferably in cold water, does not make it suitable for use in a humid environment. In light of all the technical limitations shown by the aforementioned materials, as well as the growing demand for producing a "printed thin layer with signs" for use among others in the field of food, this invention consists of the selection of a mono or biorientated film, which can be stretched and peeled, highly transparent and its use for film and vacuum packaging of noble products, in particular food products intended to be displayed elegantly on a table or platform or a thermoformed tray . This invention consists in using a highly transparent film for film and vacuum packaging of products, in particular of food products intended to be elegantly displayed on a tray, or a thermoformed container which is covered with an initially flat top strip and which it only heats up According to a feature of the invention, the stretchable film is a film oriented, printed or intended to be printed on the back by flexography or by multicolor heliography in trichromy and quadrichromy, for example, made of polyethylene terephthalate of the type ylarMR M45 (coated with PVDC of 1 μ) or MylarMR P25 type sold by DuPont de Nemours "". A oriented polypropylene or nylon film oriented by monoaxial or biaxial stretching can also be used. The machines used to manufacture decorative thin-film vacuum containers where this printed film is used are machines of the MULTYIVACMRR530 type, which includes units for forming, filling and welding of the KIT ISOPACKMR type. According to a further development of the invention, the film has one of the following structures: stretchable film, oriented / reverse printing / adhesive / polyethylene; film that can be stretched, oriented / printed on the reverse / adhesive / polyethylene; - film that can be stretched, oriented / printed on the reverse / adhesive / ionomer; stretch / oriented film / adhesive / polyethylene, - stretch / oriented film / adhesive / co-extruded welding material; film that can be stretched / oriented / printing / adhesive / ionomer. The ionomer can be a coextruded solder material intended to form a barrier film, in particular this relates to Surlyn ™. These features and other features and details of the invention will appear during the course of the detailed description below of a preferred embodiment of the invention with reference to the drawings appended thereto provided by way of non-restrictive illustration. In the drawings: Fig. 1 is a perspective view of a vacuum thin film gasket whose upper film is implmented by means of a film made of polyester, according to the invention; Fig. 2 is a schematic view of a vacuum thin film impactor machine, of the Multivac ™ type using an upper film made of polyester; Figure 3 is a perspective view of the machine illustrated in Figure 2; Figure 4 shows on a larger scale the heating and vacuum welding unit of an ISOPACKMR system of the machine shown in Figures 2 and 3; Figures 5 to 10 illustrate schematically the various steps of the IS0PACK ™ system using the film according to the invention. In the various figures, the same reference numerals designate identical or analogous elements. It is known from EP-A-0039056 a method and a machine for implementing a protective packaging and vacuum packaging of a display container of a noble product, in particular with a high-quality food product, by means of a film that can be stretched and detached. Such a machine comprises, as illustrated in FIG. 4, a welding vacuum heating unit called "station s inMR" of the IS0PACKMR system in which the product to be packaged 5 is placed in the slightly thermoformed lower support 2. 14 and is returned to the vacuum by means of an upper film 1 initially flat and heated in the unit in order to allow the latter to take the exact form of all the shapes of the product to be packaged 5. Figure 5 shows the The upper vacuum sucks the upper film into the dome and the vacuum generated in the lower part allows the slightly thermoformed lower support 2 to be secured securely in the mold. Figure 6 shows that the upper film is heated by the welding plate. Figures 7 and 8 show that by a more or less rapid return to the atmosphere of the unit, the upper film comes off and takes all the exact contours of the product to be packed. During this phase, the film is welded on the entire surface surrounding the product to be packed, as well as on the contours of the packaging due to the peripheral solder plate adapted to the ISOPACKHR system. Figure 9 shows that the welding plate moves away after sealing. Figure 10 shows the complete opening of the unit, once the packing process has been completed. The upper film 1 is guided, at its lateral edges, by the guide chains 7 from the insertion in the vacuum chamber upwards to the outlet of the vacuum pack 3, and the lower strip 2 is guided by the guide chains 4 from its insertion up just in front of the vacuum chamber 9 (figure 3). The guide chains 4, 7 have flat connections 10 and the flat connections of the guide chains 4, at the moment of release of the lower strip 2 at the front of the vacuum chamber 9, move away by inclination, laterally of the lower strip 2, by means of a lifting ring 11 which tapers conically outwards. The upper film 1 is held to the left and to the right by chains with hooks and moves in each cycle of forward movement with a drive and positioning device. A corner cutting device 12 provides the package with a loosely attached loose corner which serves to assist in the opening. In the forming unit 13, the lower strip is heated and pre-transformed into containers 14. The product 5 to be packed is manually or automatically placed in the container 14. The upper film 1 is unrolled by an uncoiling system with Adjustment of film tension. Two chains with hooks 7 provide the guidance of the upper film 1 in the heating unit 6, where it is softened by the heat in contact. In the next cycle, the lower and upper films arrive, synchronously and in parallel to a vacuum chamber of the thin-film unit. The upper soft film 1 surrounds the container 14 and the product 5 which exceeds the container 14 by a maximum of 10 mm.

The camera closes and a vacuum is generated in it. The upper film l, which is further heated in the dome, is then vacuum welded to the container over the entire surface around the product and without wrinkling. The devices 15 and 16 longitudinal and transversal cutting separate the individual packages 8 when separating them by cutting the film.

Claims (9)

1. A method for packaging and sealing under vacuum a food product display container by means of a water insoluble stretch film, the above film is thermally welded to the package, the method is characterized in that the film is rotatable and soluble in water. used which has a front side and a reverse side turned towards the container, the stretched film mentioned above is printed on the side-on the reverse and complexed by means of an adhesive to a welding support and wherein the support in the form of film complexes is welded onto the container in order to obtain a release film.

2. The method according to claim 1, characterized in that the adhesive is a water-based adhesive.

3. The method according to claim 1 or 2, characterized in that the welding support is a support in polyethylene, a co-extruded support or an ionomer support.

4. The method according to one of the preceding claims, characterized in that the film is subjected to mechanical and axial stretching before printing on its reverse side.

5. The method according to claim 4, characterized in that the film is a polyester, polyamide or polypropylene film.

6. The method according to claim 5, characterized in that the stretched film has a thickness that varies from 10 to 50 μm.

7. The method according to one of claims 1 to 6, characterized in that the stretched and printed film forms complexes with the welding support by means of an adhesive and has one of the following structures: stretched film / printing on the back of the film / adhesive / welding support in polyethylene; stretched film / printing on the back of the film / adhesive / co-extruded welding support; stretched film / printing on the reverse side of the film / adhesive / ionomer support.

8. The method according to claim 7, characterized in that the adhesive is a water-based adhesive.

9. The method according to one of claims 1 to 8, characterized in that the stretched film is printed on the reverse side by heliography or multicolor signal flexography.