EP2186742A1 - Film packaging bag, especially for powdery, dusty filling goods - Google Patents

Abstract

The invention relates to a film packaging bag, in particular for powdery, dusty filling material, with two opposite, of a bag film (1) formed by longitudinal edges (4, 4 ') limited front surface (2) and with at least one vent having a longitudinally extending ventilation duct (6). According to the invention, the vent is arranged in the region of one of the longitudinal edges (4), this longitudinal edge (4) being designed as a folding edge. The ventilation duct (6) is delimited by the folded edge and a longitudinal sealing seam (5) which separates the ventilation duct (6) from a filling space on the inside of the bag. An interruption of the longitudinal sealing seam (5) forms an inlet opening (14) leading to the filling space, to which an outside outlet opening (7) of the ventilation channel (6) is offset. The invention also provides a method for producing the film packaging bag.

Description

The invention relates to a film packaging bag, in particular for powdery, dusty filling material, with two opposite, formed by a bag film and bounded by longitudinal edges front surfaces and with at least one ventilation device having a longitudinally extending ventilation duct. The ventilation device can be provided depending on the application for a vent, ventilation or combined ventilation.

For a variety of products, a permanent venting is provided to permanently prevent swelling of the foil packaging bags. It should be taken into account that, in particular in the case of chemical products such as gypsum, cement, tile adhesive or the like, gaseous substances can also be formed during storage, which could also lead to bursting of the film packaging bag if ventilation is insufficient.

A film packaging bag with the features described above is known from EP 0 768 245 A1 Known, wherein edges of the bag film overlap on one of the two front surfaces and are connected there with two parallel longitudinal sealing seams. One of the longitudinal sealing seams has an interruption, which opens into a filling space of the bag and forms an inlet opening of a ventilation channel formed between the two sealing seams, wherein at least one outlet opening of the ventilation channel displaced in the longitudinal direction by an outside opening in the bag film or an interruption in the other sealing seam is formed. The production of the film packaging bag is complicated because two parallel sealing seams have to be produced. Since the ventilation channel is arranged in a central region of one of the front surfaces, there is also an increased risk that the inlet opening added with the contents and then a safe ventilation can not be guaranteed. Furthermore, the described bag film must be heat-sealable both on the inside and on the outside. Due to its bulbous shape designed as a simple tubular bag foil packaging bag can be stacked or placed poorly.

Against this background, the invention has for its object to provide a permanently ventilated film packaging bag, which is suitable for powdery and dusty filling material and can be produced in a simple manner. In particular, the stability of the film packaging bag should also be increased and the risk of the ventilation channel becoming clogged with the contents should be reduced.

The object is achieved in that the ventilation device is arranged in the region of one of the longitudinal edges, which is designed as a folded edge, that the ventilation duct is limited by the folding edge and a longitudinal sealing seam which separates the ventilation duct from a bag inside filling space and that an interruption of Longitudinal sealing seam forms an opening into the filling space opening, to which an outside outlet opening of the ventilation duct is arranged offset. According to the invention, it is provided to form the ventilation channel on the side of the film packaging bag in the region of the folded edge, for which purpose only a single longitudinal sealing seam has to be produced. By the lateral arrangement of the ventilation duct and the formation of the longitudinal sealing seam is also achieved that in comparison to the known from the prior art embodiment immediately before the inlet opening a smaller amount of contents is present, so that reduces the risk of clogging the inlet opening of the ventilation duct can be. Finally, the stability of the foil packaging bag can be increased by the lateral longitudinal sealing seam. The assignment of the terms In the context of the invention, the inlet opening and the outlet opening primarily serve to distinguish and only correspond to the actual direction of flow during a gas exchange in the event of venting out of the bag.

To fill the film packaging bag with powdery, dusty filling material, for example, building materials such as cement, gypsum or tile adhesive or powdered products of the chemical or food industry, this is not yet sealed at its top or bottom. After a closure of the bag, preferably by a transverse sealing seam, ensures the ventilation duct permanent ventilation.

The film packaging bag is preferably formed by folding and sealing from the bag film, wherein edges of the bag film can be connected to a longitudinal edge on which no ventilation device is provided by means of a continuous longitudinal seam. Since the inner surfaces of the bag film can be placed directly on top of each other, the outer layer does not have to be heat-sealable in the case of a multilayer configuration of the bag film.

According to a preferred embodiment of the invention, the film packaging bag is designed as a side-folding bag with arranged between the front surface gussets, the then four longitudinal edges are each formed between one of the gussets on the one hand and one of the front surfaces on the other. If, as described above, it is also provided in such an embodiment to connect the edges of the bag film to one another at one of the four longitudinal edges with a continuous longitudinal seam, the other three longitudinal edges are formed as folded edges and are expediently provided with longitudinal sealing seams. A side gusset bag thus formed is characterized by a very good stability and can be stored standing in the formation of a stand. In addition, a cuboid shape results, so that a plurality of foil packaging bags can be easily and space-saving stored and also stacked.

In the described embodiment of the foil packaging bag as side gusseted bags ventilation channels can be provided at several of the longitudinal edges formed as folding edges, without the production cost is substantially increased. Even if the inlet opening of a ventilation duct is clogged, safe ventilation and / or ventilation can be ensured by the further ventilation ducts and, for example, swelling of the foil packaging bag can be avoided.

The outside outlet openings formed in the bag film can be formed, for example, by punches or cuts.

If the venting device is provided for venting, the formation of outlet openings is preferred by means of incisions, which cut through both layers of the bag film which are superimposed on the associated folding edge. Corresponding incisions can be produced in a particularly simple manner with knives in the production of the film packaging bag. If only cuts are provided, there is also the advantage that a certain valve function is achieved. The invention is based on the finding that a high pressure in the bag and inflation should be avoided by the ventilation, but on the one hand, an excessive entry of ambient air, moisture or steam should be avoided and on the other hand, a slight overpressure, not to a excessive inflation of the bag, can be tolerated and even be beneficial in terms of the entry of undesirable substances during storage. It is also essential that through the ventilation duct with the longitudinally arranged inlet and outlet openings a Labyrinth seal is achieved. Punches are particularly advantageous when the ventilation device is provided for controlled ventilation. Controlled ventilation may be provided for food, for example.

With regard to the specific design of the at least one ventilation duct, various advantageous design possibilities arise within the scope of the invention. Thus, the ventilation duct can be formed between the associated folding edge and a longitudinal sealing seam slightly offset inwardly from the folding edge, which has an approximately constant thickness above and below the interruption, whereby a ventilation duct is formed which extends over the entire length of the longitudinal edge , Without limitation, it can be provided that several interruptions are provided as inlet openings and / or a plurality of outlet openings in order to ensure permanent loading and / or venting on the longitudinal sealing seam.

According to an alternative embodiment, it is provided that the at least one ventilation duct extends over part of the length of the associated longitudinal sealing seam, wherein preferably the portion of the longitudinal sealing seam laterally delimiting the ventilation duct has a smaller thickness than a section adjoining the outlet opening of the ventilation duct. This results in the advantage that the corresponding longitudinal edge above and below the ventilation duct is completely sealed. In addition, the ventilation duct is also limited to the filling space of the film packaging bag by a narrow web of the longitudinal sealing seam. In the context of such an embodiment, the at least one venting channel can be optimally integrated into the associated longitudinal edge. In particular, the stability of the longitudinal edge and the visual appearance are virtually unaffected. The ventilation channel integrated into a section of the longitudinal edge is also extra special advantageously protected against kinking or damage. In the context of the embodiment described, a plurality of ventilation ducts which are spaced apart from one another in the longitudinal direction and are independent of one another can be formed on the longitudinal edges of the film packaging bag which are formed as fold edges.

In the context of the described embodiment it can be provided that each of the ventilation channels has an inlet opening and an outlet opening, wherein the ventilation channel is L-shaped. Conceivable, however, are embodiments in which two spaced-apart outlet openings are provided with an inlet opening arranged therebetween in a T-shaped arrangement. A C-shaped configuration results when an outlet opening is provided between two staggered inlet openings.

The above-described ventilation according to the invention is intended to allow a pressure equalization during storage of the film packaging bags and in particular to avoid overpressure within the film packaging bag. In addition, in the filling of powdery, dusty contents often has the problem that the air contained in the film packaging bag during filling can not escape easily. In order to allow an additional, rapid venting during filling is provided in a preferred embodiment that on the inside of the bag a vent opening having inner film is provided, which is only partially connected to the bag film, so that when filling the film packaging bag from the filling displaced air can enter through the ventilation openings in areas between the inner film and the bag film and can leave these areas through a head-side filling opening. This additional intended for the filling vent is also referred to as primary venting, wherein the after the closure of the film packaging bag according to the invention provided ventilation by means of the ventilation ducts is referred to as secondary ventilation.

In the context of the present invention, there is the advantage that the primary ventilation and the secondary ventilation can be implemented completely independently of one another and also by means of different ventilation paths. Accordingly, depending on the geometry of the film packaging bag and the intended contents also independent optimization of the primary vent on the one hand and the secondary venting on the other hand done. Thus, for example, the number of ventilation ducts or vents, the size of the respectively provided openings and openings and the length and width of the ventilation ducts can be adjusted according to the respective requirements.

The vent openings provided for the primary venting on the inner film can be produced, for example, by a needling, whereby the puncturing direction must also be taken into account. Thus, seen in the puncture direction on the back of the film on which emerge the needle tips, formed on throws. The inner film can be arranged such that the elevations are arranged in the direction of the bag film or in the direction of the bag interior. In the first case, the elevations serve as spacers, so that in the areas in which the inner film and the bag film are not connected to each other, a distance from the bag film is produced, which promotes a particularly rapid primary vent. On the other hand, if the protrusions are arranged in the direction of the bag interior, this leads to an increase in the roughness. In a reciprocal needling or in sections mutual needling can also be combined, the two effects described, the increase in the roughness may in particular amount to during the filling of the film packaging bag even at high filling speeds to achieve a uniform distribution of the contents.

The bag film and the inner film are preferably connected to each other in the region of the longitudinal edges, wherein the areas arranged therebetween remain unconnected. The connection between the inner film and the bag film can be effected for example by heat sealing or preferably by adhesive.

The invention also provides a process for producing a film packaging bag, wherein a web of a bag film is folded to form at least one folding edge, wherein the edges of the bag film are joined together to form a flattened film tube having two front surfaces, wherein at the fold edge a longitudinal sealing seam is formed with at least one interruption such that at least in sections between the longitudinal sealing seam and the folding edge a channel extending in the longitudinal direction, unsealed portion is formed and wherein at the channel-shaped portion for forming a ventilation duct at least one outlet opening is generated. The outlet openings can be produced, for example, with knives which produce small incisions in the area of the channel-shaped, unsealed sections, which are also referred to as microcuts. Alternatively, however, the outlet openings can also be punched out.

To produce a ventilation duct, it may be provided to produce the longitudinal sealing seam with a substantially equal width and in an offset to the folding edge. According to an alternative embodiment, the longitudinal sealing seam is formed directly on the folded edge, wherein the longitudinal sealing seam, starting from the interruption in at least one direction has an edge-side recess, whereby the formed by the recess channel-shaped unsealed portion which forms the ventilation duct by a narrow web of the longitudinal sealing seam is separated from the interior of the film tube.

According to a preferred embodiment of the invention, side folds are formed when folding the film tube, which are arranged between the front surfaces. The generation of gussets can be carried out, for example, with folding knives. The folding is preferably carried out in such a way that the edges of the bag film are superimposed on one another at a longitudinal edge, the film tube then being closed circumferentially by sealing the edges together. In an embodiment with gusset then the other three longitudinal edges are present as folded edges, which are also preferably provided with longitudinal sealing seams. When producing the longitudinal sealing seams, the ventilation ducts described above are formed on at least one of the folded edges, preferably on a plurality of folded edges, by a corresponding configuration of the respective longitudinal sealing seam.

From the formed film tube, individual film packaging bags are finally separated, which are initially open at the top or the bottom to allow subsequent filling.

According to a preferred embodiment of the method, it is provided that the web of the bag film is laminated in sections before being folded with another film web provided with ventilation openings, wherein the laminated composite is subsequently folded such that the further film web forms an inner film of the film tube, wherein the lining preferably takes place in the areas in which subsequently longitudinal or folding edges of the film tube are produced. Instead of lamination with adhesive can also be provided to connect the inner film and the bag film by heat sealing.

The vent openings in the inner film can be produced for example by a needling, wherein a generation of vent openings is preferably provided only in the areas that are not laminated with the bag film. The bag film and the inner film can be laminated in such a way that raised portions formed during the needling are arranged in the direction of the bag film. By such an arrangement it can be achieved that at least a small distance remains between the bag film and the inner film, which facilitates the air discharge through the vent openings and the area between the inner film and the bag film when the bag is filled.

Within the scope of the invention, the bag film can be formed without restriction as a monofilm, multilayer laminated film or coextruded film. Suitable, for example, is a multilayer film having an outer layer of polyester, preferably polyethylene terephthalate (PET) and a heat-sealable inner layer of polyolefin, preferably polyethylene (PE). In the case of a multilayer laminated pouch film, in particular an internal printing can also be provided. The optionally provided inner film must be sealable to produce the longitudinal sealing seams and is preferably also formed from a polyolefin, for example polyethylene (PE). Also advantageous is an embodiment in which the inner film and the single or multilayer bag film are made entirely of PE. In addition to a better recyclability, a higher friction is achieved in a stacking of the film packaging bag and accordingly reduces the risk of slippage of the bag from each other.

Fig.1a

einen erfindungsgemäßen Folienverpackungsbeutel während der Befüllung,

Fig. 1b

der Folienbeutel gemäß Fig. 1a im geschlossenen Zustand,

Fig. 2

ein Schnitt entlang der Linie A-A der Fig. 1a

Fig. 3a - 3d

alternative Ausgestaltungen von Entlüftungskanälen im Bereich einer Längskante des Folienverpackungsbeutels,

Fig. 4

einen Kaschierverbund zur Bildung des Folienverpackungsbeutels.

The invention will be explained in the following with reference to a drawing showing only one exemplary embodiment. They show schematically:

1a

a film packaging bag according to the invention during filling,

Fig. 1b

the foil bag according to Fig. 1a when closed,

Fig. 2

a section along the line AA the Fig. 1a

Fig. 3a - 3d

alternative embodiments of ventilation channels in the region of a longitudinal edge of the film packaging bag,

Fig. 4

a Kaschierverbund to form the film packaging bag.

Fig. 1a shows a film packaging bag according to the invention during the filling with a powdery, dusty filling material.

The film packaging bag has two front surfaces 2 formed by a bag film 1 and side folds 3 arranged between the front surfaces 2. In each case formed between a front surface 2 and a side gusset 3 longitudinal edges 4, 4 'each have a longitudinal sealing seam 5, 5'. The edges of the bag film 1 are superimposed on one of the longitudinal edges 4 'and connected there with a continuous longitudinal seam 5', wherein the further longitudinal edges 4 are formed as folded edges. The longitudinal sealing seams 5 provided there serve, on the one hand, to reinforce the film packaging bag. Furthermore, ventilation channels 6, which are explained in detail below, are integrated into the longitudinal edges 4 designed as fold edges, which open into outlet openings 7 on the outside, respectively. The ventilation channels 6 are used to allow ventilation after closing the film packaging bag and in particular to avoid the build-up of an overpressure within the film packaging bag.

In order to allow the filling of the discharge of air, which is displaced by the poured material, an additional inner film 8 is provided on the inside of the packaging bag, the vent openings 9 identifies in the form of a perforation. How to compare the Fig. 1a and the Fig. 2 it can be seen, the inner film 8 and the bag film 1 are connected to each other only in the region of the longitudinal edges 4, 4 'by adhesive 10, wherein the vent openings 9 are preferably provided only in the non-interconnected areas. Instead of the described lamination with adhesive 10 but can also be provided to connect the inner film 8 and the bag film 1 by heat sealing. Thus, for example, the inner film 8 and the bag film 1 may be overlapped only immediately upon formation of the bag and then joined by the longitudinal and transverse sealing seams provided for the formation of the bag, thereby eliminating the need for prior lamination or prior heat sealing.

The vent holes 9 can be produced for example by a needling, in which case, as in the Fig. 2 shown formed by the needling at the vent holes 9 elevations 11 are arranged in the direction of the bag film 1 and serve as spacers in the unconnected areas. During the filling of the film packaging bag, the air displaced by the filling material can pass through the ventilation openings 9 into a space between the inner film 8 and the bag film 1 and leave the unclosed film packaging bag on its upper side. In order to avoid that when filling the in Fig. 1 a indicated hopper is accidentally inserted between the bag film 1 and the inner film 8, a fixing point a is provided at the upper edge, which can also be formed by adhesive 10 or a heat seal.

The bag film may be multi-layered. Thus, in the embodiment, a multilayer laminated pouch film with a transparent outer layer 12 made of polyester, preferably PET and a white inner layer 13 of polyolefin, preferably polyethylene, provided before the lamination of the outer layer 12 with the inner layer 13 an internal printing can be provided. Also, the inner film 8 may be formed multi-layered. Thus, for example, it is expedient to form the inner film 8 as a polyethylene coextrusion film, wherein the bag inner side film layer to increase the surface roughness of a filler, such as chalk, can be mixed.

Various embodiments of the inventively provided ventilation ducts 6 are in the Fig. 3a to. 3d shown. The ventilation duct 6 is in each case arranged in the region of one of the longitudinal edges 4, which is designed as a folded edge, wherein the ventilation duct 6 is delimited by the longitudinal sealing seam 5 by the folded edge and in the direction of the bag-inside filling space. At least one inlet opening 14 of the ventilation duct 6 is formed in each case by an interruption of the longitudinal sealing seam 5, wherein in each case at least one outlet opening 7 of the ventilation duct 6 is arranged in an offset.

According to the embodiment of the Fig. 3a extends the longitudinal sealing seam 5, starting from the inlet opening 14 in a closed film packaging bag with a substantially constant thickness to the bag bottom to a lower side transverse seam 15 and the head of the film packaging bag up to a top-side transverse seam 15 '. Accordingly, the formed ventilation duct 6 extends substantially over the entire length of the longitudinal edge 4 of the film packaging bag.

The Fig. 3b to 3d show embodiments in which the ventilation ducts 6 each extend over only a part of the corresponding longitudinal edge 4, wherein the longitudinal sealing seam 5 in the region of the ventilation duct 6 has a smaller thickness and forms in the direction of the filling space a web 16 delimiting the ventilation duct 6. Above and below the ventilation duct 6, the longitudinal sealing seam 5 has a greater thickness and is preferably in accordance with Fig. 3b to 3d arranged directly on the longitudinal edge 4. The described embodiments are characterized by the fact that the visual appearance and the stability of the longitudinal edge 4 reinforced by the longitudinal sealing seam 5 are not or at least not substantially impaired. In addition, the ventilation ducts 6 are also protected by the above and below immediately adjoining sections of the longitudinal sealing seam 5 and the web 16 formed by the longitudinal sealing seam 5. Fig. 3b shows an L-shaped configuration of the ventilation duct 6 with an inlet opening 14 and an outlet opening 7. In addition, T-shaped configurations with an inlet opening 14 and two outlet openings 7 (FIG. Fig. 3c ) and with a C-shaped configuration with two inlet openings 14 and an outlet opening 7 is possible ( Fig. 3d ).

Due to the offset between the inlet opening 14 and the outlet opening 7, a labyrinth-like seal is achieved. Furthermore, it is advantageous if the outlet openings 7, as shown in the exemplary embodiments, are formed as short cuts, so-called microcuts, whereby a certain valve effect is achieved overall and, during storage, the entry of undesired substances, such as liquid or water vapor, into a certain extent Dimensions can be prevented. Alternatively, however, can also be provided punch-outs, which are particularly useful when a largely free and direct exchange of air and in particular an entry of ambient air to be made possible. To allow an adaptation to the respective requirements can be provided, for example, the length and width of the ventilation duct 6 and the size and arrangement of the inlet opening 14 and the outlet opening 7 to change. Finally, on the longitudinal edge 4, several of the in the Fig. 3b to 3d shown ventilation ducts 6 may be provided at a distance from each other.

Fig. 4 shows a Kaschierverbund to form a packaging bag according to the invention, which is designed as a gusseted bag. The laminating composite comprises a web of the bag film 1 and a further film web applied thereon, which forms the inner film 8 in the Folienverpackungsbeutein. Again Fig. 4 can be seen, the inner film 8 and the bag film 1 are laminated in strip-shaped areas 17 by adhesive 10 together and unconnected between these areas 17. Before the sectional lamination of the inner film 8 with the bag film 1 are in the areas that are not laminated with the bag film 1, produced by a needling vent openings 9. In the Fig. 4 is further indicated that in the formation of a film tube, are separated from the individual film packaging bag, the fold edges formed as longitudinal edges 4 and the longitudinal sealing seams 5, 5 'in the interconnected by adhesive regions 17 are generated. The edges of the Kaschierverbundes be connected by means of a continuous longitudinal seam 5 'at a longitudinal edge 4'.

Claims (18)

Film packaging bag, in particular for powdery, dusty filling material, having two opposing front surfaces (2) formed by a bag film (1) and bounded by longitudinal edges (4, 4 ') and having at least one ventilation device having a longitudinal ventilation duct (6) , characterized in that the ventilation device is arranged in the region of one of the longitudinal edges (4), which is designed as a folded edge, that the ventilation duct (6) by the folded edge and a longitudinal sealing seam (5), the ventilation duct (6) of a bag inside Filling space separates, is limited and that an interruption of the longitudinal sealing seam (5) forms an opening in the filling space inlet opening (14), to which an outside outlet opening (7) of the ventilation duct (6) is arranged offset. Film packaging bag according to claim 1, characterized in that the ventilation duct (6) extends over part of the length of the associated longitudinal edge (4), wherein the ventilation channel (6) laterally limiting portion of the longitudinal sealing seam (5) has a smaller thickness than a at the outlet opening (7) of the ventilation duct (6) subsequent section. Film packaging bag according to claim 1, characterized in that the ventilation channel (6) has a plurality of outlet openings (7). Film wrapping bag according to one of claims 1 to 3, characterized in that between the front surfaces (2) side folds (3) are arranged, wherein the longitudinal edges (4, 4 ') between one of the side folds (3) on the one hand and one of the front surfaces (2 ) are formed on the other hand. Film packaging bag according to one of claims 1 to 4, characterized in that on one of the longitudinal edges (4 ') a longitudinal sealing seam (5') is provided, which edges of the bag film (1) connects to each other. Film packaging bag according to one of claims 1 to 5, characterized in that the bag film (1) has an outer layer (12) made of polyester, preferably polyethylene terephthalate (PET), and a heat-sealable inner layer (13) of polyolefin, preferably polyethylene (PE). Film packaging bag according to one of claims 1 to 6, characterized in that on the inside of the bag a vents (9) having inner film (8) is provided, which is only partially connected to the bag film (1), so that when filling the film packaging bag with a pulverulent, dusty filling material, the air displaced from the filling space through the ventilation openings (9) in areas between the inner film (8) and the bag film (1) enter and leave these areas through a head-side filling opening. Follenverpackungsbeutel according to claim 7, characterized in that the bag film (1) and the inner film (8) in sections by adhesive (10) are interconnected. Film packaging bag according to claim 7 or 8, characterized in that the bag film (1) and the inner film (8) in the region of the longitudinal edges (4,4 ') are interconnected, wherein the interposed regions are unconnected. Method for producing a film packaging bag, in particular a film packaging bag according to one of claims 1 to 9,
wherein a web of a bag film (1) is folded to form at least one folding edge,
the edges of the bag film (1) being joined together to form a flattened film tube having two front surfaces (2),
wherein at the folded edge a longitudinal sealing seam (5) is formed with at least one interruption such that at least in sections between the longitudinal sealing seam (5) and the folding edge, a longitudinally extending channel-shaped unsealed portion is produced, and
wherein at the channel-shaped portion for forming a ventilation duct (6) at least one outlet opening (7) is generated. The method of claim 10, wherein to form the channel-shaped, unsealed portion, the longitudinal seal seam (5) is produced with a substantially constant width and offset from the fold edge. Method according to claim 10, wherein the longitudinal sealing seam (5) is formed directly at the folding edge and wherein the longitudinal sealing seam (5) has a peripheral recess starting from the interruption, whereby the channel-shaped, unsealed portion formed by the recess passes through a narrow web (16). the longitudinal sealing seam (5) is separated from the interior of the film tube. Method according to one of claims 10 to 12, wherein in the folds of the film tube gussets (3) are formed, which are arranged between the front surfaces (2). Method according to one of claims 10 to 13, wherein the web of the bag film (1) before folding with a further, provided with ventilation openings (9) film web is laminated in sections, wherein the laminating composite is folded such that the further film web an inner film (8 ) of the film tube forms. A method according to claim 14, wherein the web of the bag film (1) and the further film web are laminated in the regions (17) in which subsequently longitudinal edges (4, 4 ') of the film tube are produced. Method according to one of claims 10 to 13, wherein the web of the bag film (1) before folding a further, provided with vents (9) film web is fed, wherein the bag film (1) and the further film web are joined by heat sealing and wherein the Bag film is folded with the other film web such that the further film web forms an inner film (8) of the film tube. Method according to one of claims 14 to 16, wherein the vent openings (9) are produced only in the areas which are not provided for connection to the bag film (1). Method according to one of claims 14 to 17, wherein the ventilation openings (9) are produced by a needling and wherein the further film web is so connected to the web of the bag film (1) that formed during the needling Aufwerfungen (11) in the direction of the bag film (1) are arranged.

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