FR2806033A1 - Complex film for deforming into yogurt pots, etc. has first polymeric film with distorted decorative motif and second polymeric film adhered to first film - Google Patents

Abstract

A complex film has a first polymeric film with a distorted decorative motif and a second polymeric film adhered to the first film. Independent claims are included for the following: (a) Forming a decorated container by applying a distorted motif to a first thermoplastic film, then adhering a second thermoplastic film to the first film and deforming the complex film to make the container. (b) A decorated container made as above. Preferred Features: The first film is 20 - 200 micro m thick and the second film 200 - 1600 micro m thick. Both films are made of the same polymer. A gas impermeable barrier resin layer lies between the two films. The films are joined by applying a thermally activated adhesive to one or both of them, bringing them together and then heating them. The motif is formed on the face of the first film adhered to the second film.

Description

The present invention relates to a receptacle manufacturing process in the form of a decorated bowl, of the type comprising the steps consisting of a) decorating a sheet of polymer material with an anamorphic pattern; and b) deforming the sheet carrying the morphed pattern to form said receptacle.

This process is particularly suitable for the production of yoghurt pots or food packaging containers.

Nowadays, receptacles constituted by pots formed of polymer are commonly used for the packaging of food products. These pots are decorated externally in order to improve the visual appearance and to identify their content.

According to this process, a banner of pre-printed paper is laminated externally around the end of the pot, after thermoforming of it.

This process poses problems of fouling of the machines, in particular of the bar feeders and of the units for placing the banners, when the self-adhesive hot-melt glue used (hot melt) is rubbed on the rollers or when it comes into contact with that. - with the pieces.

Furthermore, document FR-A-2,676,966 describes a process for manufacturing a three-dimensional thermoformed part from a flat support previously printed by hot sublimation of polymeric materials. It is envisaged to print on the flat support, prior to thermoforming, an anamorphic pattern, which, after the deformation obtained during thermoforming, will form the external decoration of the three-dimensional piece.

In this document, the sublimation printing process described with precision. However, the actual manufacturing of the three-dimensional parts pre-printed using an anamorphic pattern is described only briefly and the process used involves a significant cost in machine investments.

The object of the invention is to propose a manufacturing process which can be used industrially and universally on existing thermoforming machines, in particular by making it possible to obtain satisfactory quality of the products, as well as good reproducibility.

In fact, the subject of the invention is a method of manufacturing a receptacle in the form of an externally decorated bowl, of the precise type characterized in that the step of decorating the sheet with an anamorphic pattern comprises the following successive phases a first film of polymer material with an anamorphic pattern - and B - laminating a second film of polymer material on the first film decorated with the anamorphic pattern to form said sheet carrying the anamorphic pattern.

According to particular modes of shaping, the method comprises one or more of the following characteristics - the thickness of the first film is less than the thickness of the second film; - first film has a thickness between 20 and 200 microns; - second film has a thickness of between 200 and 1 mi crons; - first and second films are formed from the same polymeric material; - the laminating step comprises the phases of A - applying on at least one of the facing faces of the first and second films a heat-activatable sealing lacquer; B - bring the two films into contact according to their opposite faces - and C - activate the sealing lacquer by heating; - the deformation of the sheet carrying the anamorphic pattern comprises a thermoforming phase of said sheet; - The thermoforming phase includes an initial heating phase of the sheet carrying the anamorphic pattern at different temperatures according to distinct zones, followed by a subsequent shaping phase; - the anamorphic moti is applied to the face of the first film which is laminated to the second film; - resin forming a gas-impermeable barrier is applied between the first film and the second film; and the second film has a composition suitable for constituting a barrier impermeable to gases.

The invention further relates to a receptacle in the form of a bowl manufactured by a process as defined above.

The invention finally relates to a complex film intended for the manufacture of a receptacle as described above, characterized in that it comprises a first film of polymer material decorated with an anamorphic pattern and a second film of laminated polymer material on the first film.

The invention will be better understood on reading the description which follows, given solely by way of example and made with reference to sins, on which - Figure 1 is a sectional view of a pot of yoghurt obtained by a manufacturing process according to the invention; - Figure 2 is a schematic view of a plant for manufacturing pots such as that shown in Figure 1 and implementing the process assigned according to the invention; and.

- Figure 3 is a sectional view of a yogurt pot obtained implementation of a variant of the method according to the invention.

In Figure 1 is shown a bowl-shaped receptacle 10 constituting a pot of yogurt. A jar of this type can also be used for the packaging of crème fraîche, cottage cheese, dairy desserts, butter, prepared meals, or more generally, of any foodstuff.

The pot 10 is generally of revolution. It has a bottom with a cylindrical dress 14 and an outer peripheral rim 16 bordering the access opening 18. The rim 16 is capable of receiving a cover for closing the opening 18.

The pot 10 is produced by the method according to the invention which will be explained precisely in the following description. This pot is obtained by thermoforming a complex sheet, that is to say formed from at least two adjoining films. In the example shown, the pot 10 has a thick inner film 20 disposed towards the inside of the pot. This film is laminated to a thin outer film 22 which is provided with decorative patterns 24.

The decorative patterns 24 are revealed during thermoforming by deformation of an anamorphic pattern previously printed on the outer film 22, which is then laminated to the inner film 20. The decorative patterns 24 are worn on the face of the outer film 22 applied against the inner film 20.

The method for manufacturing the pot 10 will now be described with reference to FIG. 2, on which is shown a manufacturing installation implementing the method according to the invention.

This installation includes means 52, 54 for continuously or stepwise unwinding of two coils 56, 58.

It comprises means 60 for bringing the films contained in the two reels into contact with one another. Downstream of these, means 62 are arranged for heating the two adjoining films. These means comprise, for example, sources of infrared radiation as well as means for establishing a layer of hot air in contact with the films to be bonded. Downstream of these, means 64 for thermoforming the pots are arranged, followed by a unit 66 for filling and sealing the pots.

The reel 56 is formed from a pre-printed polymer film wound itself. This film, noted 56A, is intended to constitute the external film 22 of the pot.

The film 56A comprises, on its face arranged opposite the film contained in the reel 58, and denoted 58A, an anamorphic pattern printed in marked areas. This anamorphic pattern is printed beforehand on the film 56A on a separate machine, for example using engraved printing cylinders. This printing is done in flexography or rotogravure.

The printed patterns are anamorphic patterns whose shape is such that, after deformation of the film during thermoforming in the means 64, the desired patterns for the decoration of the pot are formed on the pot.

The outer film 56A is transparent in order to reveal the printed pattern. It is, for example, a polystyrene film. Its thickness is advantageously between 20 and 200 microns, and preferably between 150 and 180 microns, in order to allow easy passage of the machine film.

The film 58A, contained in the reel 58, is intended to form the internal film 20 of this film a thickness greater than that of the film 56A carrying the anamorphic patterns. Its thickness is advantageously between 200 and 1600 microns and preferably between 600 and 750 microns. composition of film 58A preferably identical to that of film 56A. So the two films here are polystyrene.

As a variant, the films used for films 56A, 58A can be all the flexible or rigid amorphous films in the conventional families of polystyrene, polypropylene, polyamide, polyvinyl chloride, polyester terephthalate amorphous, polyacrylonitrile.

The face of the film 56A oriented towards the film 58A is coated with a heat-activated lacquer formed for example by a varnish or a heat-sealing coating. This heat-activated lacquer is previously applied to the film 56A on a separate machine, according to a known technique.

Lacquer can be applied to either wire. In fact, it is preferably applied to the thinnest film, which is easier to handle.

In the means 60, the two films 56A and 58A are first applied one against the other. During their continuous or step-by-step passage through the means 62, the application of heat causes the thermal activation of the la that, leading to the sealing of the two films against each other, producing a complex film designated by the general reference 100.

This complex film is conveyed to the thermoforming means 64 where the jar is shaped, after having been heated, by stamping in two suitable complementary dies.

Advantageously, the thermoforming means are adapted to ensure a regular distribution of the material along the entire length and the entire periphery of the dress 14. To this end, upstream of the complementary dies, heating means making it possible to apply heat different according to identified areas of the complex film are put ceuvre. These heating means are formed for example of machined heating plates having zones of different heights (thermal masking), these plates being applied to the surface of the complex film 100. This thermal masking is determined so that the temperature of the ma material at the time of thermoforming is within the temperature range allowing ideal deformation of the material.

During the actual stamping between the complementary dies, the regions of the complex film previously heated to distinct temperatures deform in a differentiated manner as a function of their temperature, thus ensuring a better distribution of the material during shaping.

With the method according to the invention, the quality of the rendering of the decorative decorative patterns is high. Indeed, the anamorphic patterns being printed on a suitable thin i, which is only subsequently laminated against a thicker support film, it is possible to obtain a final rendering much superior to that which can be obtained by a printing carried out directly with a single film. of polymer whose thickness is equal to the sum of the thicknesses of the two films 56A and 58A.

In particular, the gloss of the decorative pattern obtained is high, then the printing is protected under a transparent film.

In the method of implementing the method described here, all of the manufacturing steps are implemented in the same installation. Thus, the manufacture of the complex film 100 and its thermoforming to obtain pots, are carried out online on the same strip of complex sheet. In this case, since the thermoforming carried out in the means 64 is carried out sequentially on batches of pots, the complex film should be introduced step by step into the thermoforming means 64. Thus, the unwinding of the films and 58A is also carried out step by step, as is their combination to form a complex in the means 60 and 62.

According to a variant implementation of the method, the production of the complex film 100 is carried out on a machine separate from the machine performing thermoforming. In particular, these two distinct phases of the process can be implemented in different factories.

In this case, the manufacture of the complex film 100 is carried out continuously, the complex film being wound on itself to form a coil at the outlet of the heating means 62. The coil thus formed is conveyed to the installation of thermoforming or the complex film is introduced step by step into the thermoforming machine.

In Figure 3 is shown an alternative embodiment of the according to the invention. In this figure, elements similar or corresponding to those of the embodiment of Figure 1 are designated by the same reference numbers.

In this variant embodiment, the prints 24 are formed on the surface of the outer film 22. Thus, the prints are not enclosed between the two films 22 and 24 but are arranged on the free surface of the outer film 22. For this purpose, the film 56A is printed on its face opposite to that laminated on the film 58A.

According to another variant, the prints are carried by the surface of the film 58A intended to be laminated on the film 56A, the latter then being covered along its face applying to the film 58A with a heat-reactivated lacquer.

Finally, it is also possible to provide prints on both sides of the outer film.

In addition, with the method according to the invention, when the inks are sandwiched between the two films, the inks are unlikely to migrate, guaranteeing compliance with food constraints.

Furthermore, the two films can also be produced in different materials if this results in technical or economic advantages. However, the materials used for the two films are advantageously the same, the pots thus formed then being mono-material, which facilitates their recycling.

According to yet another variant of the embodiment described with reference to FIG. 1, the pot comprises, between the two films 22 and 24, a resin forming a barrier impermeable to gases and in particular to oxygen. This resin is formed for example of poly (vinylidene chloride), of polyvinyl alcohol) or of a copolymer of ethylene and of vinyl alcohol. It is applied to the anamorphic patterns carried by the film 56A before the application of the heat-activated lacquer. The film surface is coated with the resin by coating with an organic aqueous solvent.

The application of a barrier resin protects the contents of the pot from any harmful action which may result from the entry of gas inside the pot. in particular, the enzymes used in yogurt are protected.

According to another variant of the embodiment of FIG. 1, the film 24 consists of a complex film adapted to form an impermeable barrier to gases. Thus, the internal film 24 is a coextruded sheet, the layers of which consist for example of polystyrene - copolymer of ethylene and vinyl alcohol - polyethylene. This film can also be made of polypropylene - copolymer of ethylene and vinyl alcohol - polyethylene.

Claims (1)

<U> CLAIMS </U> 1.- Method of manufacturing a receptacle (10) in the form of a decorated bowl, of the type comprising the steps consisting of a) decorating a sheet (100) of polymer material with an ana- morphose; and b) deforming the sheet (100) carrying the anamorphic pattern to form said receptacle (10), characterized in that the step of decorating the sheet (100) with an anamorphic pattern comprises the following successive phases A - decorating a first film (56A) of polymeric material with an anamorphic pattern; and B - laminating a second film (58A) of polymer material on the first film (56A) decorated with the anamorphic pattern to form said sheet (100) carrying the anamorphic pattern. 2.- Method according to claim 1, characterized in that the thickness of the first film (56A) is less than the thickness of the second film (58A). 3.- Method according to claim 1 or 2, characterized in that the first film (56A) has a thickness between and 200 microns 4.- A method according to any one of the preceding claims, characterized in that the second film (58A) has an "issuer between 200 and 1600 microns. 5.- Method according to any one of the preceding claims, characterized in that the first and second films (56A, 58A) are formed from the same polymeric material. 6.- Method according to any one of the preceding claims, characterized in that the laminating step comprises the phases of A - applying to at least one of the viewing faces of the first and second films (56A, 58A) a sealing lacquer heat-activated; B - bringing the two films (56A, 58A) into contact along their opposite faces; and C - activate the sealing lacquer by heating. 7.- Method according to any one of the preceding claims, characterized in that the deformation of the sheet (1 carrying the anamorphic pattern comprises a thermoforming phase of said sheet. 8.- Method according to claim 7, characterized in this thermoforming phase comprises an initial phase of heating the sheet 00) carrying the anamorphic pattern at different temperatures in different zones, followed by a subsequent shaping phase. 9.- Method according to any one of the preceding claims, characterized in that the anamorphic pattern is applied to the face of the first film (56A) which is laminated to the second film (58A). 10.- Method according to any one of the preceding claims, characterized in that a resin forming a gas-impermeable barrier is applied between the first film (56A) and the second film (58A). 11.- Method according to any one of the preceding claims, characterized in that the second film (58A) has a composition suitable for constituting an impermeable barrier to gases. 12. A receptacle (10) in the form of a bowl manufactured by a process according to any one of the preceding claims. 13.- Complex film (100) intended for the manufacture of a receptacle (10) in the form of an externally decorated bowl, characterized in that it comprises a first film (56A) made of polymer material decorated with an anamor phose pattern and a second film (58A) of polymeric material laminated to the first film (56A).