FR2810640A1 - Package for drink has flexible film(s) between two sheets with joins between film(s) and sheets - Google Patents

Abstract

A package has flexible film(s) between two sheets with joins between film(s) and the sheets. The above package (a) has two flexible films and the end of at least one films is folded over another sheet opposite the join(s). A package (b) also has joins between the films and between the films and the sheets. A package (c) has a flexible film folded on itself and placed between sheets. The film has joins to itself and to the sheets. An Independent claim is also included for a method of making (a) or (b) by inserting the films between the sheets and forming the joins; a method of making (c) by inserting a screen film between the folds of the film, joining the film to itself, removing the screen film and joining the film to the sheets. Preferred Features: A straw can be inserted into the fold formed in the films

Description

<U> PACKAGING WITH </ U> SYSTEM <U> OF CLOSURE BY </ U> BAND, <U> METHOD FOR ITS MANUFACTURING </ U> The subject of the invention is a new flat closure system, adapted on packaging of type sachets, especially plastic. These packages or bags may be "Doypack" or so-called "three welds" bags.

Many plastic packages or bags, with or without a valve, are already known.

 GB-A-826 784 discloses a bag which is obtained by successively folding a plastic film. This film is folded a first time along a straight line with a central orifice, two solder zones are applied, and the film is folded on itself. The three free sides are welded, as well as a part of the fourth side carrying the bellows with the V-welds. The presence of the opening at the bottom of the bellows, as well as the presence of the two V-welds and the partial welding of the side of the opening, would allow proper operation of the valve formed by the central orifice.

 FR-A-2 711 115 discloses an inflatable bag provided with a valve. This bag is obtained by forming two parallel welds in a film folded on itself, which is then folded back on itself in a manner similar to that of GB-A-826 781. In this case however, the doubly folded film on itself is welded so as to leave the folded edges of the film accessible from the outside.

 WO-A-95/23742 discloses a complex system obtained by successive folding with intermediate welding steps. According to a first variant, the bag obtained is double-walled. According to one embodiment, from this first variant, it is possible to produce a flexible pouch with a single wall. In this case, the valve system consists of an attached film, which is pierced by application of a straw. This film can be aluminum or polymer. At first, according to this document, a weld hole is cleaned along two parallel lines (between which the straw will be placed). This part is then folded over the sheet which is welded along its ends. Another sheet is then added to form the container. The straw pierces the operculum, but when the straw is removed, the two walls are pressed against each other by the pressure of the fluid.

The above systems, however, have several disadvantages. They are complex and require a complex folding device. They do not allow the consideration of plugs, often associated with this type of product.

The invention makes it possible to remedy the defects of the systems of the prior art. Thus, the invention provides a package (1) comprising at least two sheets (2, 3), at least one flexible film in the form of a strip (4; 10a, 10b; 16), said at least one film being welded to the sheet (3) according to at least one weld (5; 11b; 17b) extending along one end of said film, and said at least one film being furthermore welded to the sheet (2) according to at least two welds (6a, 6b 12a, 12b, 18a, 18b) extending across the width of said film.

According to a first embodiment, the packaging according to the invention comprises a flexible film (4) welded to the sheet (3) according to a weld (5) and to the sheet (2) according to the welds (6a, 6b).

According to this embodiment, the packaging according to the invention may be such that the flexible film is peelable or repositionable, and is furthermore welded to the sheet (2) by a weld (9).

According to a second embodiment, the packaging according to the invention comprises two films (10a, 10b) welded to the sheets (2, 3) by the welds (11a, 11b) respectively, and welded together and to the sheets (2, 3) by the welds (12a, 12b), one of the two films being folded over the other at the end of the films, opposite the welds (11a, 11b). According to one variant, the packaging according to the invention comprises two films (loa, 10b) welded to the sheets (2, 3) by the welds (11a, 11b) respectively, and welded together by the welds (12'a, 12). b) and to the sheets (2, 3) by the welds (12a, 12b), the welds (12'a, 12'b) being between the welds (12a, 12b), one of the two films being folded over the other at the end of the films, opposite to the welds (11a, 11b).

According to another variant, the package according to the invention comprises two films (loa, 10b) welded to the sheets (2, 3) by the welds (11a, 11b) respectively, and welded together and to the sheets (2, 3). by the welds (12a, 12b), the two films being folded on themselves at the end of the films opposite to the welds (11a, 11b).

According to another variant, the package according to the invention comprises two films (10a, lob) welded to the sheets (2, 3) by the welds (11a, 11b) respectively, and welded together by the welds (12'a, 12'b) and the sheets (2, 3) by the welds (12a, 12b), the welds (12'a, 12'b) being between the welds (12a, 12b), the two films being folded over themselves at the end of the films opposed to the welds (11a, 11b).

According to this second embodiment, the packaging according to the invention may be such that the fold formed by the film (s) can be unfolded by introducing a straw between the films (10a, lob) .

According to this second embodiment, the package according to the invention may also be such that the fold formed by the film (s) is not likely to be unfolded by introducing a straw.

According to this second embodiment, the packaging according to the invention may also comprise an additional weld (25) between the sheets (2, 3).

According to a third embodiment, the packaging comprises a flexible film (16) folded on itself and welded to the sheets (2, 3) by the welds (17a, 17b) respectively and welded to itself and to the sheets ( 2, 3) by the welds (18a, 18b).

According to one embodiment, in the package according to the invention, the flexible film is PE, EVA, PP, OPP, PET, PA. According to one embodiment, in the package according to the invention, the sheets (2, 3) are semi-rigid.

According to one embodiment, in the package according to the invention, the sheets (2, 3) and the flexible film (4; 10a, 10b; 16) have the following characteristics, with H the thickness in mm and E the equivalent module of the film in <B> N. </ B> MM-2: sheet (2, 3): H3 E = 0.1 to 50 nm film (4; 10a, 10b; 16): H3E = 0.5.10 -3 to 5 N.mm; with preferably: sheet (2, 3): H3 E = 0.5 to 25 nm film (4; 10a, 10b; 16): H3 E = 0.05 to 1 mm, with, in both cases, the relation: H3E film (4; 10a, 10b; 16) <H3E (2, 3).

According to one embodiment, the package according to the invention is in the form of a Doypack bag or three-welds.

The invention also relates to a method of manufacturing a package, in particular according to the first embodiment, comprising the following steps: - welding of the film (4) on the sheet (3) according to the weld (5); inserting a film-screen (7) between the film (4) and the sheet (3); - Welding of the film (4) on the sheet (2) according to the welds (6a, 6b); and - extraction of the screen film (7).

The invention also relates to a method of manufacturing a package, in particular according to the second embodiment, comprising the following steps: - insertion of a film-screen (7) between the films (10a, 10b); soldering the films (10a, 10b) on the sheets (2, 3) according to the welds (11b) respectively; extraction of the screen film (7); optionally welding the films (10a, 10b) together according to the welds (12'a, 12) and - welding the films (10a, 10b) and sheets (2, 3) together according to the welds (, 12b). Another subject of the invention is a method of manufacturing a package, in particular according to the third embodiment, comprising the following steps: - insertion of a film-screen (7) into a fold formed by the film (16) - soldering of the film (16) ) on the films (2, 3) according to the welds (17a, 17b) respectively; - extraction of the film-screen (7); and - welding of the film (16) and sheets (2, 3) together according to the welds ( 18a, 18b).

According to one embodiment, the screen film (7) is made of PTFE or teflon fabric. The invention is now described in more detail in the description which follows, and with reference to the drawings, in which: FIG. 1 represents a first embodiment of the invention; Figures 2a and 2b show the operation of this first embodiment of the invention; FIG. 3 represents a method of manufacturing this first embodiment of the invention; Figures 4a and 4b show the filling of this first embodiment of the invention; Figures 5a and 5b show two variants of a second embodiment of the invention; FIG. 6 represents this second embodiment of the invention; FIG. 6a represents a variant of this second embodiment of the invention; Figures 7a and 7b show the operation of this second embodiment of the invention; Figures 8a and 8b show a method of manufacturing this second embodiment of the invention; Figures 9a and 9b show the filling this second embodiment of the invention; Figures 10 and 11 show a third embodiment of the invention; Fig. 12 shows a plug for use with this third embodiment of the invention; Figures 13a and 13b show a manufacturing method of this third embodiment of the invention; FIGS. 14a and 14b show the filling of this third embodiment of the invention; FIG. 15 represents a variant of the first and second embodiments of the invention.

1, the invention provides a bag 1 comprising two sheets 2, 3 facing one another. These sheets are made conventional material in the art, including plastic such as PET, OPP, PA, etc. These two films are particularly semi-rigid, in that they are likely to be deformed to accept the dilation of the bag while providing a general pouch hold. The thickness of these two sheets is conventional in the art, for example a thickness of between 0.001 μm and preferably 60 μm to 250 μm. Between these sheets 2 and 3 is a flexible film 4.

The flexible is made of a suitable material, in particular a plastic material. This film 4 may be especially PE, or EVA, PP, OPP, PET, PA, etc. This film has a thickness between 10 and 500 μm, and preferably between 30 and 100 gm.

In general, these sheets 2 and 3 and this flexible film 4 have modules and thicknesses such that with H the thickness in mm and E the equivalent module lm in N. MM-2: semi-rigid sheet: H3 E = 0.1 to 50 N.mm flexible film: H3 E = 0.5.10-3 to 5 N.mm preferably: semi-rigid sheet: H3 E = 0.5 to 25 N. mm flexible film: H3 E = 0.05 to 1 N.mm with, in both cases, the relation: H3E flexible film <H3E semi-rigid sheet.

This film 4 is welded over part of its length, end of the sheet 3 according to the weld 5 (which is represented here by hatching). This film is also welded, over part of its width to the sheet 2, according to two welds 6a and 6b which define the width of the valve. These welds may be parallel or otherwise, perpendicular or not to the weld 5. These welds 5 and 6a and 6b are arranged so that the weld 5 extends substantially between the welds 6a and 6b, which contributes to the seal. Preferably, the weld 5 extends completely between the welds 6a and 6b. The welds 6a and 6b extend substantially over the width of the film strip 4, or even exceed this width. This very simple system offers the same advantages as the prior art, in particular WO-A-95 23742, but without the disadvantages of successive and numerous folds and welds.

By way of example, the film is in the form of a strip having a width of between 5 and 200 mm, and preferably between 10 and 50 mm. The length of the strip (in fact this time the width of the bag) is between 20 and 1500 mm, preferably between 50 and 400 mm.

Figures 2a and 2b show the operation of the valve thus formed. In Figure 2a, the valve is in the open position (for example by introducing a straw). The film 4 is then in contact with the sheet 3. When the system is released, the internal pressures (for example by the mere weight of the contents) come to press the film 4 on the sheet 2 with which it is welded according to the welds 6a and 6b. Thus, the tightness is achieved. Figure 2b illustrates this case; it is a section along the weld 6b to better indicate the phenomenon. The arrows indicate the thrust operated for example by a fluid in the bag.

FIG. 3 represents, in section, and illustrates a manufacturing diagram of the bag of FIG. 1. The manufacture makes use of a film-screen which allows a selective welding of the flexible film 4, either on the sheet 2, or on the 3. In a first step, the film 4 is welded in the form of a strip on the sheet 3 in a weld 5. Next, a film 7 forming a screen is introduced between the film strip 4 and the sheet 3. then affix the sheet 2 on the previous structure, and it is placed between two jaws of a welding machine or solder bars. One of them, the jaw 8a is for example at room temperature while the jaw 8b is at a temperature sufficient to weld the film 4 to sheet 2 according to the welds 6a and 6b. It is also possible to have a heated strip on a silicone counterpart. It is also possible that both jaws are at the soldering temperature, depending on the film and rate. For example, the welding temperature may be between 130 and 250 C, depending on the material to be welded. Once the weld has been performed, the screen film 7 is removed. The closure system shown in FIG. This screen film 7 is made of a material that is substantially insensitive to heat and does not adhere to the film at the soldering temperature. It may be for example PTFE, or other material, such as teflon fabric. One could also have an inverse sequence with formation of the welds 6a and 6b, insertion of a sheet 7 between these welds, then formation of the weld 5.

The closure system shown in Figure 1 (and referred to as type I in the following) can be adapted to lower cost on existing bags. These sachets are the classic sachets, such as "Doypack", 3-weld bag, etc. Reference may be made to, for example, application FR 9 811 622, US Pat. No. 3,380,646 and patent addition certificate FR-A-1,327,875. The closure system may be placed in the center. or on one side of the bag, according to convenience. In most cases, a straw or other similar instrument will be provided with the bag. This straw, inserted between the sheets 2 and 3, is guided to the system according to the invention, spreads the sheets 2 and 3 at the weld 5, and is positioned naturally between the welds 6a and 6b. When the straw is removed, the walls formed on the one hand of the film 4 and on the other hand of the sheet 2, are pressed one on the other. This gives a seal.

This system may also comprise, as film 4 (or possibly as sheet 2), a repositionable film. Such films are known and comprise a support film 4a, an adhesive layer 4b and a sealing layer 4c. the welding layer is welded, along a bead, on the sheet 2 facing it (or on a sealing layer affixed to said sheet 2). When tearing the band corresponding to the welded portion is secured to the sheet 2, which discovers the adhesive. Then, after the straw has been removed, apply pressure to completely close the system.

Such repositionable films are described for example in WO-A-9719867. We can also use, not a repositionable film, but a peelable film. Such films are known and, unlike the previous films, do not comprise a permanent adhesive layer but an intermediate layer 4d. These films ensure, as before, the integrity of the bag before straw boring, but they are not repositionable. In these two cases, it is possible to weld the film strip 4 on the sheet 2 according to an additional weld 6c, located between the welds 6a and 6b, at the lower end thereof (the weld 5 being at the upper end ). This weld 6c may be performed at the same time as the welds 6a and 6b, or later, according to the conventional techniques indicated in the documents of the prior art referred to above.

The bag equipped with the opening system according to the invention of type I fills in a conventional manner, as illustrated in Figures 4a and 4b (the closure system according to the invention being on one side of the bag). The weld 5 extends, as shown, over the entire length of the sheet 3 (but there could be solder 5 only on the part between the welds 6a and 6b). In the measurement the film 4 is welded to the sheet 2 at the welds 6a and 6b, there is therefore a space between the film 4 and the sheet 2 on the area between the weld 6a and the rest of the bag. So we have a filling area represented by the arrow. Once the filling is completed, it is welded according to the weld 9 which extends from the weld 6a to the end of the bag, as shown in Figure 4b. This solder weld together the sheets 2 and 3 and the film 4.

Figures 5a 5b show, in section, a second embodiment of the invention. In this embodiment, the film 4 is replaced by two films 10a and 10b. Each film 10a and 10b is welded to the sheets 2 and 3, respectively, according to welds 11a and 11b (equivalent to the weld 5 according to the type I embodiment). In Figure 5a, the film 10a is not folded, while it is folded in Figure 5b. These two new types are called type IIa and type IIb, respectively.

FIG. 6 represents a view in the closed state of these second embodiments. Note the presence of two vertical welds 12a and 12b, which weld together the two sheets 2 and 3 and the films 10a and 10b. These welds 12a and 12b may be parallel or not, perpendicular or not to the welds 11a and 11ab. These welds 11a and 11b extend substantially between the welds 12a and 12b; preferably, the welds 11a and 11b extend completely between the welds 12a and 12b. The welds 12a and 12b extend substantially over the width of the film strips 10a and 10b, or even exceed this width. The valve defined by the welds 12a and 12b is then substantially sealed.

FIG. 6a shows a closed state view of a variant of these second embodiments (in which the welds 11a and 11b have not been shown, and in which all the films and sheets have been represented). Note the presence of two vertical welds 12'a and 12'b, which weld together the films 10a and 10b, in their unfolded position. These welds 12'a and 12'b are between the welds 12a and 12b, which they weld together the sheets 2 and 3, and the films 10a and 10b, this time in the folded position. This variant makes it easier to open by increasing the locking width of the fold; this gives a greater flexibility on the height of the fold. The welds 11a and 11b likewise extend here completely between the welds 12a and 12b. The position of the welds 12'a and 12'b relative to the welds 12a and 12b can vary widely. In general, the spacing between these welds 12'a and 12'b will represent between 5 and 50%, preferably between 10 and 35%, of the spacing between the welds 12a and 12b. The valve defined by the welds 12'a and 12'b is here also substantially sealed. The other features described with reference to FIG. 6 apply mutatis mutandis.

The operation of the valve is better explained with reference to FIGS. 7a and 7b (with for example the type IIa, first variant -i.e. without the welds 12'a and 12'b-). Figure 7a shows the closed valve, a fold of the film 10b covering the film 10a and sealing. The introduction for example of a straw between the sheets 2 and 3 causes the separation of the films 10a and 10b and the opening of the valve as shown in FIG. 7b is obtained. When the straw is removed, the films 10a and 10b return to their original position and the valve is closed again. Straw (or any other equivalent device such as a plug or funnel) may be present when the bag is empty. It is then replaced, then the straw is removed, which closes the bag. This system is particularly suitable when the (s) fold (s) of (the) film (s) 10a and 10b extend over a large part of the width (taking into account the spacing of the welds). In this case it is difficult for the user to discard the films 10a and 10b from the fold; the delivery of the empty bag-in the open position-with the straw (or any other device) makes it a "trash" or scrap pouch that is very tight once straw is removed. The latter variant is particularly suitable for dangerous products such as: cooking oil, waste oil, solvents, residues and industrial sludge.

Thus, according to the chosen configuration, a reversible or irreversible operation is obtained. In the case of reversible operation, with opening / closing cycles, there is a spacing between the welds 12a (respectively 12'a) and 12b (respectively 12'b) large in front of the height of the fold. In the case of irreversible operation, the bag being delivered open, with only the possible closure, there is a spacing between the welds 12a (respectively 12'a) and 12b (respectively 12'b) small before the height of the fold. The choice of the respective dimensions is within the reach of the skilled person.

The characteristics of the films (thickness, etc.) are substantially the same as for the type I. The (s) fold (s) represents (s), in% of the spacing of the welds 12a (respectively 12'a) and 12b (respectively 12'b), between 5% and 50%. If opening with a straw is desired, the fold (s) generally represent 5 to 25%. If it is desired that the opening can not be done, the (s) fold (s) represent) in general, from 25 to 50%.

FIGS. 8a and 8b illustrate the process for preparing the type IIa or IIb sachets (Type IIa, first variant) has been chosen here. FIG. 8a shows sheets 2 and 3, films 10a and 10b, and a screen film 7 of the same type as that used for the manufacture of the type I bag. Welding strips 13a and 13b heated. at the soldering temperature are applied to obtain the welds 11a and 11b. The screen film 7 is removed, and then, as shown in FIG. 8b, vertical welding strips 14a and 41b heated to the soldering temperature of the sheets 2 and 3 and films 10a and 10b are applied to obtain the welds 12a and 12b. Any other welding device of the bar / counterpart type is also usable.

In the case of the second variant, the method further comprises the step 12'a welds and 12'b. In such a case, it is possible to separate the sheets 2 and 3 of the films 10a and lob to proceed with the welding. We can also fold the sheets 2 and 3 on themselves, to completely release the films 10a and 10b which is then very easy to weld them.

Figures 9a and 9b show the filling area. The closure system according to the invention is shown on one side of the bag. The welds 11a and 11b on the one hand, and 12a and 12b on the other hand, are already affixed. Figure 9a shows the free space between the loa film and the sheet 2, which allows the filling schematically by the arrow. Once the filling is completed, the solder 15 is welded which extends from the weld 12a to the edge of the bag, as shown in FIG. 9b. This solder weld together the sheets 2 and 3 and the films 10a and 10b.

Figure 10 shows a third embodiment (hereinafter type III). In this embodiment, the film 16 in the form of a strip is folded on itself and welded to the sheets 2 and 3 by the welds 17a and 17b. This film 16 is similar in nature to that of the films 10a, lob and 4.

Figure 11 shows a side view, in which the welds 18a and 18b are visible. These welds may be parallel or not, perpendicular or not to the previous welds. The welds 17a and 17b extend substantially between the welds 18a and 18b, preferably completely between them. The welds 18a and 18b extend substantially over the folded film bandwidth 16, or even exceed this width.

The valve thus formed is called type III. Unlike the types I and IIa and IIb, the film 16, the original state, does not allow the passage of a straw. It is necessary to pierce the flexible film 16. The piercing tool is preferably a piercing plug 19, as shown in Figure 12. The piercing tool can also be a straw.

The piercing stopper 19 represented in FIG. 12 comprises a body 20 through which a channel 21 passes. Advantageously, the piercing stopper also comprises a piercing tube 22. The body advantageously comprises a thread or grooves, which will make this stopper integral with the flexible film 16. This film 16 is preferably elastic in order to obtain a diaphragm effect enclosing the plug. Finally, this plug 19 can be provided with a cap 23 which can be screwed. This cap can be simple, spout, reclosable, invidable, with child-safety, etc.

Figure 13a shows the first step of a scheme for making the type III bag. As previously, the manufacturing uses a screen film 7. At first, the film 16 is welded on the sheets 2 and 3 according to the welds 17a and 17b, the film 7 being inserted into the fold of the film 16. Welding strips 24a and 24b weld according to the welds 17a and 17b. The screen film 7 is then removed, and solder strips 25a and 25b weld together the sheets 2 and 3 and the folded film 16 according to the welds 18a and 18b.

Figures 14a and 14b show the filling. The closure system according to the invention is shown on one side of the bag. The welds 17a and 17b on the one hand, and 18a and 18b on the other hand, are already affixed. In Figure 14a, there is shown the free space between the film 16 (folded) and the sheet 2, which allows filling schematically by the arrow. Once the filling is completed, solder 26 is welded which extends from the weld 18a to the edge of the bag, as shown in FIG. 14b. This solder weld together the sheets 2 and 3 and the folded film 16.

Figure 15 shows an embodiment common to types I and IIa / IIb. According to this embodiment, the sheets 2 and 3 are further welded along an additional line 27, affixed to an extension of the sheets 2 and 3. A weakening line or a simple marking 28 may be affixed under the weld 27 in order to prompt the user to cut the bag according to this marking. The additional welding ensures a total seal.

The invention, by its variants of type I, II (IIa / IIb) and III thus offers many advantages, by the combination of two sheets 2 and 3 semi-rigid forming the body of the bag and one (two) film ( s) flexible (s) 4; 10a, 10b; 16. The characteristics of the sheets and films are common to all the embodiments and the description given with reference to FIG. 1 applies mutatis mutandis to the other variants of the invention. Likewise, the other characteristics (width, length, operating conditions, welding conditions, etc.) when they are not specified specifically in the embodiment, are common to the various variants of the invention.

The sachet according to the invention is. - waterproof - by welding - by contact film / film - by folding of films - by contact film / plug reported - by ZIP lock system (two profiles, generally extruded, which cooperate by interlocking one into the other) - by peelable / repositionable film (type I) - openable and resealable - by insert plug (type III) - by mechanical operation of the sealing system (type I, II) - tamper evident - attached plug (type III) - welding - film / sheet or - leaf / leaf.

sachet according to the invention also has the advantage of being flat (before filling), which facilitates handling, decreases the volumes of packaging sachets.

sachet has an overall thickness generally less than 2 mm, preferably less than 500 Mm. sachets are suitable in all technical fields, including food, chemistry, cosmetic detergents; for small liquids, powders, granules or solids (eg candies). As mentioned above, the bag may be for single use as "trash".

The type III bag (with plug) allows the plug function to be integrated in the manufacturing logic and in the soft bag processes (such as Doypacks and three-weld bags).

Finally, it will be appreciated that the sheets and films may comprise conventional additives, and be made of several layers, as is known in the art. Thus the films or sheets may comprise several layers, one of which is weldable.

The invention is not limited to the embodiments shown but is capable of many improvements easily accessible to those skilled in the art.

Claims (1)

1. Packaging (1) comprising at least two sheets (2, 3), at least one flexible film in the form of a strip (4; 10a, 10b; 16), said at least one film being welded to the sheet (3) in at least one weld (5; 11b; 17b) extending at one end of said film, and said at least one film being further welded to the sheet (2) in at least two welds (6a, 6b; 12a, 12b; 18a, 18b) extending across the width of said film. 2.- Package according to claim 1, comprising a flexible film (4) welded to the sheet (3) according to a weld (5) and the sheet (2) according to the welds (6a, 6b). 3. Packaging according to claim 2, wherein the flexible film is peelable or repositionable, and is further welded to the sheet (2) by a weld (9). 4.- Package according to claim 1, comprising two films (10a, 10b) welded to the sheets (2, 3) by the welds (11a, 11b) respectively, and welded together and to the sheets (2, 3) by the welds (12a, 12b), one of the two films being folded over the other at the end of the films, opposite the welds (11a, 11b). 5.- Package according to the claim comprising two films (10a, 10b) welded to the sheets (2, 3) by the welds (11a, 11b) respectively, and welded together by the welds (12'a, 12'b) and to the sheets (2, 3) by the welds (12a, 12b), the welds (12'a, 12'b) being between the welds (12a, 12b), one of the two films being folded over the other at end of the films, opposed to the welds (11a, 11b). 6. Packaging according to claim, comprising two films (10a, 10b) welded to the sheets (2, 3) by the welds (11a, 11b) respectively, and welded together and to the sheets (2, 3) by the welds ( 12a, 12b), the two films being folded on themselves at the end of the films opposite the welds (11a, 11b). 7.- Package according to claim 1, comprising two films (10a, 10b) welded to the sheets (2, 3) by the welds (11a, 11b) respectively, and welded together by the welds (12'a, 12'b ) and the sheets (2, 3) by the welds (12a, 12b), the welds (12'a, 12'b) being between the welds (12a, 12b), the two films being folded on themselves at the end of the films opposite the welds (11a, 11b). 8.- Package according to any one of claims 4 to 7, wherein the fold formed by the (s) film (s) can be unfolded by introduction of a straw between the films (10a, 10b). 9.- Package according to any one of claims 4 to 7, wherein the fold formed by the (s) film (s) is not likely to be unfolded by introduction of a straw. 10.- Package according to any one of claims 2 to 9, comprising an additional weld (25) between the sheets (2, 3). 11. A package according to claim 1, comprising a flexible film (16) folded on itself and welded to the sheets (2, 3) by the welds (17a, 17b) respectively and welded on itself and to the sheets (2). , 3) by the welds (18a, 18b). 12. Packaging according to any one of claims 1 to 11, wherein the flexible film is PE, EVA, PP, OPP, PET, PA. 13.- Package according to any one of claims 1 12, wherein the sheets (2, 3) are semi-rigid. 14. The package according to any one of claims 1 to 13, wherein the sheets (2, 3) and the flexible film (4; 10a, 10b; 16) have the following characteristics, with H the thickness in mm and E the equivalent module of the film in N.mm-2: sheet (2, 3): H3 E = 0.1 to 50 nm film (4; 10a, 10b; 16): H3 E = 0.5.10-3 to 5 N.mm; with preferably: sheet (2, 3): H3 E = 0.5 to 25 nm film (4; 10a, 10b; 16): H3 E = 0.05 to 1 mm, with, in both cases, the relation: H3E film (4; 10a, 10b; 16) <H3E (2, 3). 15.- Package according to any one of claims 1 to 14, in the form of a Doypack bag or three-welds. 16. A method of manufacturing a package according to claim 2 or 3, comprising the following steps: - welding of the film (4) on the sheet (3) according to the weld (5); inserting a film-screen (7) between the film (4) and the sheet (3); - Welding of the film (4) on the sheet (2) according to the welds (6a, 6b); and - extraction of the screen film (7). 17. A method of manufacturing a package according to any one of claims 4 to 10, comprising the following steps. inserting a film-screen (7) between the films (10a, 10b); welding the films (10a, 10b) on the sheets (2, 3) according to the welds (11a, 11b) respectively; extraction of the screen film (7); - optionally welding the films (10a, 10b) together according to the welds (12'a, 12'b); and - welding the films (10a, 10b) of the sheets (2, 3) together according to the welds (12a, 12b). A method of manufacturing a package according to claim 11, comprising the steps of: inserting a screen film (7) into the fold formed by the film (16); - Welding of the film (16) on the sheets (2, 3) according to the welds (17a, 17b) respectively; extraction of the screen film (7); - Welding of the film (16) and sheets (2, 3) together according to the welds (18a, 18b). 19. A process according to claim 16, 17 or 18, wherein the screen film (7) is PTFE or teflon fabric.