PACKAGE WITH STRIP-BASED CLOSURE SYSTEM AND METHOD FOR ITS MANUFACTURE
The subject of the invention is a package comprising at least two sheets (2, 3) and two flexible films (10a, 10b) placed between them and 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), at least one of the two films being folded over the other at that end of the films on the opposite side to the welds (11a, 11b). The subject of the invention is also a method for manufacturing such a package. The invention makes it possible to obtain a package of simplified structure and simplified manufacture.
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This is a continuation of U.S. application Ser. No. 10/312,318, filed Aug. 4, 2003, which is a 371 application of PCT/FR01/01935 filed Jun. 20, 2001. The contents of the U.S. application Ser. No. 10/312,318 are incorporated herein by references in their entirety.
The subject of the invention is a novel flat closure system, suitable for packages of the bag type, especially those made of plastic. These packages or bags may be DOYPACK® or so-called “three weld” bags.
Many plastic packages or bags, provided with a valve or otherwise, are already known.
GB-A-826 784 discloses a bag obtained by successively folding a plastic film. This film is folded firstly along a straight line having a central orifice, two V-shaped weld regions are applied, and then the film is folded over on itself. The three free sides are welded, together with part of the fourth side having the bellows with the V-welds. The presence of the opening at the bottom of the bellows, and the presence of the two V-shaped welds and the partial weld on the side of the opening, allow the valve formed by the central orifice to operate properly.
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 over on itself, which is then again folded over on itself, in a manner similar to that of GB-A-826 781. However, in this case the film doubly folded over on itself is welded so as to leave the folded-over edges of the film accessible from the outside.
WO-A-95/23742 discloses a complex system obtained by successive folding with intermediate weld steps. According to a first variant, the bag obtained is double-walled. According to one embodiment, based on this first variant, it is possible to produce a flexible pocket 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 may be made of aluminium or of polymer. According to that document, an orifice is firstly provided by welding along two parallel lines (between which the straw will be placed). This part is then folded over on the sheet which is welded along its ends. Another sheet is then added, to form the container. The straw pierces the membrane, but when the straw is removed the two walls are pressed against each other by the pressure of the fluid.
Document JP-A-09-254999 discloses a bag made of synthetic resin. The bag consists of two films hermetically joined together laterally. A strip is placed parallel to a jaw between the two films. The strip is provided partly with a non-adhesive part. This non-adhesive part serves as a flow opening.
FR-A-1 436 217 discloses a method for manufacturing a bag for packaging drinks. According to that process, a container formed from a sheet of synthetic thermoplastic is emptied by means of a straw. The container is manufactured starting from a tube having lateral folds, the said tube being drawn from a synthetic thermoplastic sheet. The straw is introduced into the container between the lateral folds pressed against one another.
However, the above systems have several drawbacks. They are complicated and require a complicated folding device. They do not allow the incorporation of stoppers, which are often associated with this type of product.
The invention makes it possible to remedy the drawbacks of the systems of the prior art. Thus, the invention provides a package comprising at least two sheets and two flexible films placed between them and welded to the sheets by the welds respectively, and welded together and to the sheets by the welds, at least one of the two films being folded over the other at that end of the films on the opposite side to the welds.
According to one embodiment, the two films are folded over on themselves at that end of the films on the opposite side to the welds.
According to another embodiment, the package comprises at least two sheets and two flexible films placed between them and welded to the sheets by the welds respectively, and welded together by the welds and to the sheets by the welds, the welds being between the welds, at least one of the two films being folded over the other at that end of the films on the opposite side to the welds.
According to one embodiment, the two films are folded over on themselves at that end of the films on the opposite side to the welds.
According to yet another embodiment, the package comprises at least two sheets, a flexible film placed between them and folded over on itself and welded to the sheets by the welds respectively and welded to itself and to the sheets by the welds.
According to one embodiment, the fold formed by the film(s) can be unfolded by inserting a straw between the films.
According to yet another embodiment, the fold formed by the film(s) cannot be unfolded by inserting a straw.
According to another embodiment, the package has an additional weld between the sheets.
According to yet another embodiment, the flexible film is made of PE, EVA, PP, OPP, PET or PA.
Provision may also be made for the sheets to be semi-rigid.
According to one embodiment, the sheets and the flexible film have the following characteristics, where H is the thickness in mm and E is the equivalent modulus of the film in N·mm−2
sheet: H3E=0.1 to 50 N·mm;
film: H3E=0.5×10−3 to 5 N·mm;
with preferably:
sheet: H3E=0.5 to 25 N·mm;
film: H3E=0.05 to 1 N·mm;
with, in both cases, the relationship:
film H3E<sheet H3E.
According to another embodiment, the package is in the form of a DOYPACK® or three-weld bag.
The invention also relates to a method for manufacturing a package according to the teaching of the invention, comprising the following steps:
-
- insertion of a screen-film between the films;
- welding of the films to the sheets along the welds respectively;
- extraction of the screen-film;
- optionally, welding of the films together along the welds; and
- welding of the films and the sheets together along the welds.
According to one embodiment, the manufacturing method comprises the following steps:
-
- insertion of a screen-film in the fold formed by the film;
- welding of the film to the sheets along the welds respectively;
- extraction of the screen-film; and
- welding of the film and the sheets together along the welds.
According to yet another embodiment of the process, the screen-film is made of PTFE or of Teflon®-coated fabric.
The invention will now be described in greater detail in the description which follows and with reference to the drawings, in which:
Referring to the exploded view in
In general, these sheets 2 and 3 and this flexible film 4 have moduli and thicknesses such that, with H the thickness in mm and E the equivalent modulus of the film in N mm−2
semi-rigid sheet: H3E=0.1 to 50 N·mm;
flexible film: H3E=0.5×10−3 to 5 N·mm;
ith preferably:
semi-rigid sheet: H3E=0.5 to 25 N·mm;
flexible film: H3E=0.05 to 1 N·mm;
with, in both cases, the relationship:
flexible film H3E<semi-rigid sheet H3E.
This film 4 is welded, over part of its length, to one end of the sheet 3 along the weld 5 (which is shown here by cross hatching). This film is also welded, over part of its width, to the sheet 2 along two welds 6a and 6b which define the width of the valve. These valves may or may not be parallel or may or may not be perpendicular to the weld 5. These welds 5 and 6a and 6b are made so that the weld 5 lies approximately between the welds 6a and 6b, thereby contributing to the sealing. Preferably, the weld 5 lies completely between the welds 6a and 6b. The welds 6a and 6b extend approximately over the width of the strip of film 4, or even extend beyond this width. This very simple system affords the same advantages as the prior art, in particular WO-A-95/23742, but without the drawbacks of the many successive folds and welds.
As an 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.
The closure system shown in
This system may also include, as film 4 (or possibly as sheet 2), a repositionable film. Such films are known and comprise a support film 4a, a layer of adhesive 4b and a welding layer 4c. The welding layer is welded along a seam to the sheet 2 which is facing it (or to a welding layer placed against the said sheet 2). Upon tearing, the strip corresponding to the welded part is fastened to the sheet 2, thereby exposing the adhesive. After the straw has been removed, pressure may then be applied in order to completely reseal the system.
Such repositionable films are described for example in WO-A-97/19867. It is also possible to use, not a repositionable film, but a peelable film. Such films are known and, unlike the above films, do not include a layer of permanent adhesive but an interlayer 4d. These films ensure, as above, the integrity of the bag before being pierced by a straw, but they are not repositionable. In both these cases, the strip of film 4 may be welded to the sheet 2 along an additional weld 6c, lying between the welds 6a and 6b, at the lower end of the welds 6a and 6b (the weld 5 being at the upper end). This weld 6c may be made at the same time as the welds 6a and 6b, or subsequently, depending on the conventional techniques indicated in the abovementioned documents of the prior art.
The bag provided with the type I closure system is filled conventionally, as illustrated in
The operation of the valve is more clearly explained with reference to
Thus, depending on the configuration chosen, the operation is either reversible or irreversible. In the case of reversible operation, with opening/closing cycles, there is a large distance between the respective welds 12a (or 12′a) and 12b (or 12′b) compared with the height of the fold. In the case of irreversible operation, with the bag being delivered open, with only closure possible, there is a small distance between the respective welds 12a (or 12′a) and 12b (or 12′b) compared with the height of the fold. Choosing the respective dimensions lies within the competence of a person skilled in the art.
The characteristics of the films (thickness, etc.) are substantially the same as for type I. The fold(s) represents (represent), a percentage of the distance between the respective welds 12a (or 12′a) and 12b (or 12′b), between 5 and 50%. If it is desired to open the bag using a straw, the fold(s) represents (represent) in general from 5 to 25%. If it is desired that opening cannot occur, the fold(s) represents (represent) in general from 25 to 50%.
In the case of the second embodiment, the method also includes the step for the welds 12′a and 12′b. In such a case, it is possible to separate the sheets 2 and 3 from the films 10a and 10b in order to carry out the welding. The sheets 2 and 3 may also be folded over on themselves, in order to completely free the films 10a and 10b which it is then very easy to weld together.
The valve thus formed is termed type III. Unlike types I and IIa and IIb, the film 16, in the original state, does not allow a straw to pass through it. It is necessary to pierce the flexible film 16. The piercing tool is preferably a piercer stopper 19, as shown in
The piercer stopper 19 shown in
The package, by dint of its embodiments of type I, II (IIa/IIb) and III therefore has many advantages, by the combination of two semi-rigid sheets 2 and 3 forming the body of the bag and one (two) flexible film(s) 4; 10a, 10b; 16. The characteristics of the sheets and films are common between all the packages and the description given with reference to
The bag is:
-
- leaktight
- by welding,
- by film/film contact,
- by folding of the films,
- by film/attached stopper contact,
- by a ZIPLOCK system (two profiles, generally extruded, which cooperate by one fitting into the other),
- by a peelable/repositionable film (type I);
- openable and reclosable
- by an attached stopper (type III),
- by mechanical operation of the sealing system (type I, II);
- tamperproof
- by an attached stopper (type III),
- by welding
- film/sheet or
- sheet/sheet.
- leaktight
The bag also has the advantage of being flat (before filling), thereby making it easier to handle and decreasing the volumes for packaging the bags.
The bag has in general an overall thickness of less than 2 mm, preferably less than 500 μm.
The bags are suitable for all technical fields, especially the food, chemical, detergents and cosmetics fields; and they apply for liquids, powders, granules or solids of small size (for example sweets). As was indicated above, the bag may be of a use-once type, such as a “rubbish bin”.
The bag of type III (with an attached stopper) makes it possible to integrate the stopper function into the manufacturing logic and into the methods for flexible bags (such as Doypacks and three-weld bags).
Finally, it will be noted that the sheets and films may include conventional additives and may consist of several layers, as is known in the art. Thus, the films or sheets may comprise several layers, one of which can be welded.
The invention is not limited to the embodiments shown, but is easily capable of many improvements within the competence of a person skilled in the art.
Claims
1-15. (canceled)
16. A package comprising at least two sheets (2, 3) and two flexible films (10a, 10b) placed between them and welded to the sheets (2, 3) by first welds (11a, 11b) respectively, and welded together and to the sheets (2, 3) by vertical second welds (12a, 12b), the vertical second welds extending substantially over the width of the films, and the first welds extending substantially between the vertical second welds, the vertical second welds welding the films and the sheets together along the whole width of the films, and at least one of the two films being folded over the other at an end of the film on the opposite side to the first welds (11a, 11b).
17. The package according to claim 16, the two films being folded over on themselves at that end of the films on the opposite side to the first welds (11a, 11b).
18. The package according to claim 16, the two films being welded together by vertical third welds (12′a, 12′b), the vertical third welds (12′a, 12′b) being comprised between the vertical second welds (12a, 12b).
19. The package according to claim 18, the two films being folded over on themselves at that end of the films on the opposite side to the first welds (11a, 11b).
20. The package according to claim 16, in which the fold formed by the film(s) can be unfolded by inserting a straw between the films (10a, 10b), the fold(s) representing between 5% and 25% of the distance between the second welds.
21. The package according to claim 16, in which the fold formed by the film(s) cannot be unfolded by inserting a straw, the fold(s) representing between 25% and 50% of the distance between the third welds.
22. The package according to claim 16, having an additional weld (15) between the sheets (2, 3).
23. The package according to claim 16, in which the flexible film is made of PE, EVA, PP, OPP, PET or PA.
24. The package according to claim 16, in which the sheets (2, 3) are semi-rigid.
25. The package according to claim 16, in which the sheets (2, 3) and the flexible film (10a, 10b; 16) have the following characteristics, where H is the thickness in mm and E is the equivalent modulus of the film in N mm−2:
- sheet (2, 3): H3E=0.1 to 50 N·mm;
- film (10a, 10b; 16): H3E=0.5×10−3 to 5 N·mm.
26. The package according to claim 16, in the form of a DOYPACK® or three-weld bag.
27. The package according to claim 25, in which the sheets (2, 3) and the flexible film (10a, 10b; 16) have the following characteristics, where H is the thickness in mm and E is the equivalent modulus of the film in N mm−2:
- sheet (2, 3): H3E=0.5 to 25 N·mm;
- film (10a, 10b; 16): H3E=0.05 to 1 N·mm.
28. The package according to claim 25, in which the sheets (2, 3) and the flexible film (10a, 10b; 16) have the following characteristics, where H is the thickness in mm and E is the equivalent modulus of the film in N mm−2:
- film (10a, 10b; 16) H3E<sheet (2, 3) H3E.
29. The package according to claim 27, in which the sheets (2, 3) and the flexible film (10a, 10b; 16) have the following characteristics, where H is the thickness in mm and E is the equivalent modulus of the film in N mm−2:
- film (10a, 10b; 16) H3E<sheet (2, 3) H3E.
Type: Application
Filed: Jan 17, 2008
Publication Date: May 29, 2008
Applicant: SOPLARIL (Rueil Malmaison)
Inventors: Jacques Thomasset (Neuvecelle), Carine Caudron (Le Plessis Trevise), Stephane Mathieu (Fluy)
Application Number: 12/015,909
International Classification: B65D 30/24 (20060101);