FR3094351A1 - A method of manufacturing a plurality of partially open packaging bags using a transverse technique - Google Patents

Abstract

A method of manufacturing a plurality of packaging bags (1) comprising steps consisting, from a strip (7) of plastic film unrolled continuously, in: - step A: folding a strip (7) in its length to define a front wall (2) folded over a rear wall (3); - step D: insert transversely at regular intervals corresponding to the widths of the bags (1), and between the front (8) and rear (9) walls of the strip (7), folds (13) of film each defining two bellows ( 4) folded opposite one another and linked together by a longitudinal edge; - step E: weld and cut transversely the strip (7) between the two bellows (4) of each fold (13) to form the packaging bags (1); - step F: weld the openings of each bag (1) and produce at the level of one of the bellows (4) at least one transverse weakening line (15) adapted to give access to a partial opening (6) for filling after rupture of the line of weakness. According to the invention, before step D, the method comprises steps consisting in: - step B: fixing on each of the front (8) and rear (9) walls of the strip (7) and close to an edge longitudinal section of the strip (7), a first strand (10) of complementary coupling means of the hermaphrodite type, the first strands (10) being intended to face each other when the strip (7) is folded and are fixed longitudinally and discontinuously at regular intervals along the strip (7) from each transverse line (12) intended to become the side edge of a bag (1), each first strand (10) has a length corresponding to the dimension of the partial opening (6) and at least to half the width of a bellows (4); - step C: fixing over the entire width of a single bellows (4) of each fold (13) a second strand (11) of complementary coupling means of the hermaphrodite type, the second strand (11) being positioned to be able, before step E, be placed opposite the first strands (10). Figure for the abstract: Fig. 2

Description

Method of manufacturing a plurality of packaging bags with partial openings and using a transverse technique

The invention relates to the technical sector of plastic packaging bags, such as, for example, bags for packaging food products.

More particularly, the invention finds an advantageous application in the field of flexible plastic bags, in particular obtained from a strip of a film with a thickness of less than 200 μm, approximately.

This type of bag comprises at least, and in a perfectly known manner, a front wall and a rear wall, the side edges of which are connected by gussets, a bottom, and a partial filling opening.

The invention relates more particularly to a method of manufacturing a plurality of this type of bag, according to a so-called transverse technique.

Prior art

It is known from the prior art a method of manufacturing a plurality of packaging bags according to a so-called transverse technique. According to this technique, the method comprises at least steps consisting, from a strip of plastic film unrolled continuously, in:

- folding the strip along its length to define a front wall folded over a rear wall;

- insert transversely at regular intervals corresponding to the widths of the bags, and between the front and rear walls of the strip, folds of film each defining two gussets folded opposite one another and connected to each other by a longitudinal edge;

- weld and cut the band transversely between the two gussets of each fold to form the bags.

During the manufacture of this type of bag, according to the transverse technique, it is known to fix strands of complementary coupling means on the front and rear walls of the strip to allow the bags to be opened and closed at will.

According to a first technique, these coupling means are positioned above bellows, and do not encroach on the bellows which are lower than the front and rear walls of the bags.

It is therefore not possible with this type of bag to open and close the bag and one of the bellows to form a kind of spout.

According to another technique, illustrated in particular by document EP3020545, first strands of complementary coupling means are fixed continuously over the entire length of the strip, and second strands of complementary coupling means over the entire width of the two gussets of each bend.

This technique gives complete satisfaction in the case of a bag with a total opening, but seems inappropriate in the case of a bag with a partial opening.

One of the aims of the invention is therefore to remedy the aforementioned problems by providing a method of manufacturing a plurality of packaging bags with partial openings according to a so-called transverse technique, making it possible to obtain bags equipped, at the level their partial opening, complementary coupling means, to form a pouring tray.

The invention aims to provide such a manufacturing method in which the complementary coupling means are integrated into the bags, continuously, and during the bag manufacturing operation.

To solve the aforementioned problems, a process for manufacturing a plurality of packaging bags has been designed and developed, each comprising a front wall and a rear wall, the side edges of which are connected by gussets, a bottom, and a partial filling opening.

The method is in accordance with that of the state of the art in that it is carried out according to a so-called transverse technique comprising at least steps consisting, from at least one strip of plastic film unrolled continuously, in :

- Step A: folding the strip across its width to define a front wall folded over a rear wall;

- step D: insert transversely at regular intervals corresponding to the widths of the bags, and between the front and rear walls of the strip, folds of film each defining two gussets folded facing one another and connected to each other by a longitudinal edge;

- step E: weld and cut the band transversely between the two gussets of each fold to form the packaging bags;

- step F: weld the filling opening and make at one of the bellows at least one transverse weakening line adapted to give access to a partial opening of the bag after breaking the weakening line.

According to the invention and according to a first technique, the method is remarkable in that, before step D, the method comprises steps consisting of:

- step B: fix on each of the front and rear walls of the strip and close to a longitudinal edge of the strip, a first strand of complementary coupling means of the hermaphrodite type, the first strands being intended to be opposite the from each other when the strip is folded and are attached longitudinally and discontinuously at regular intervals along the strip from each of the transverse lines intended to become the side edge of a bag, each first strand has a length corresponding to the dimension of the partial opening and at least half the width of a bellows;

- step C: fix over the entire width of a single bellows of each fold a second strand of complementary coupling means of the hermaphrodite type, the second strand being positioned so that, before step E, it can be placed opposite the first strands.

From the foregoing, the method according to the invention makes it possible to integrate, directly during the manufacture of bags with partial openings, first strands on the front and rear walls of the strip, in particular intended to become the front and rear walls of the bags , as well as, in correspondence, a second strand of complementary coupling means at the level of a bellows of the bag. Thus, the method according to the invention makes it possible to obtain a bag equipped at the level of a bellows with complementary coupling means making it possible to open and close, at will, the bag at the level of the bellows and according to a partial opening, to form a spout.

According to a second alternative technique resulting from the same general inventive concept, namely the fixing of the first strands in a discontinuous manner, and to obtain the same packaging bags with partial openings, the invention also relates to an identical method, but in which, before step D, the method comprises steps consisting of:

- step B: fix on each of the front and rear walls of the strip and close to a longitudinal edge of the strip, a first strand of complementary coupling means of the hermaphrodite type, the first strands being intended to be opposite the from each other when the strip is folded and are fixed longitudinally and discontinuously at regular intervals along the strip in a symmetrical manner on either side of transverse lines each intended to become the side edge of a bag , and alternately every other line, each first strand has a length corresponding to twice the dimension of the partial opening and at least the width of a bellows;

- step C: fix over the entire width of the two bellows of one fold out of two a second strand of complementary coupling means of the hermaphrodite type, the second strand being positioned so that, before step E, it can be placed opposite the first strands.

In this way, the bags are designed alternately, that is to say that the bellows equipped with the complementary coupling means changes from one bag to the next bag.

Preferably, the method comprises an additional step consisting in transversely weakening the first strands and the second strands at the level of zones intended to be bent.

This embrittlement step can be carried out in any suitable way, and for example by removing the material constituting the first strands and the second strands, or by producing a weld or pre-cut line on the first strands and second strands.

This step of transverse embrittlement of the first strands and second strands makes it possible to facilitate the folding of the strip and of the bellows.

According to a particular embodiment, the method consists in fixing the first strands are in the form of previously cut sections.

According to another particular embodiment, the method consists of unrolling the first strands, fixing them, then cutting them transversely to the desired length

Description of figures

Other advantages and characteristics of the invention will emerge better from the description which follows, given by way of non-limiting example, from the appended figures in which:

is a schematic representation illustrating a strip of plastic film unwound continuously;

is a schematic representation illustrating the strip folded in half along its length, and the foldings of the bellows before insertion, the strip and the bellows having first and second strands of complementary coupling means of the hermaphrodite type, fixed according to a first technique;

is a schematic representation similar to that of FIG. 2, the first and second strands of complementary coupling means of the hermaphrodite type being fixed according to a second technique;

illustrates in perspective a bag obtained according to the first or the second production technique of FIGS. 2 or 3;

illustrates in perspective a bag with partial opening obtained according to the process of the invention.

With reference to Figures 1 to 5, the invention relates to a method of manufacturing a plurality of packaging bags (1) with partial openings according to a so-called transverse technique.

The packaging bags (1) obtained by means of this type of process each comprise, and in a known manner, at least a front wall (2) and a rear wall (3) whose side edges are connected by bellows (4), a bottom (5), and a partial filling opening (6).

The filling opening is partial in the sense that it does not allow opening the entire width of the bag (1). In practice, the partial opening (6) is pre-cut, at the level of one of the bellows (4) only of the bag (1) and has a dimension corresponding, for example, to half the width of the bag (1) .

Referring to Figure 1, the method comprises a step A consisting in folding a strip (7) of a film of flexible plastic material, that is to say with a thickness of less than 200 μm. The strip (7) is folded along its length to define a front wall (8) folded over a rear wall (9). According to another embodiment not shown, it is possible, and without departing from the scope of the invention, to use two strips (7) and, instead of bending, to position them one on the other to define a front wall (8) on a rear wall (9). The two strips (7) can, in a next step, be welded together at a longitudinal edge.

The method consists in fixing first strands (10) of complementary coupling means of the hermaphrodite type on the front (8) and rear (9) walls of the strip (7), and second strands (11) of means of complementary coupling of the hermaphrodite type on a bellows (4), with a view to obtaining a bag (1) of which said bellows (4) can be opened and closed, at will, at the level of a partial opening (6) by forming in particular a spout. The first (10) and second (11) strands of complementary coupling means of the hermaphrodite type are well known in the state of the art and are not described in detail.

The method comprises a step B consisting in fixing on each of the front (8) and rear (9) walls of the strip (7), and close to a longitudinal edge of the strip (7), a first strand (10) hermaphrodite-type complementary coupling means. In a particular embodiment, the first strands (10) are fixed at the level of the free longitudinal edge of the folded strip (7), in particular intended to be on the side of the opening (6) for filling the bag (1). According to another particular embodiment, and more precisely when the packaging bag (1) comprises a flat bottom, the longitudinal edge of the strip (7) intended to be on the side of the opening (6) for filling is the edge located along the fold line of the strip (7). It is therefore close to this edge that the first strands (10) are fixed in this embodiment. This edge will subsequently be cut to form the filling opening (6) of the bag (1)

The first strands (10) are intended to come opposite each other when the strip (7) is folded.

According to a first technique of the invention illustrated in Figure 2, the first strands (10) are fixed longitudinally, that is to say in the direction of the length of the strip (7) and discontinuously at regular intervals along the strip (7) from each transverse line (12), in particular fictitious, intended to become the side edge of a bag (1). Each first strand (10) has a length corresponding to the dimension of the partial opening (6) and at least half the width of a bellows (4).

Several techniques are possible for fixing the first strands (10) to the front (8) and rear (9) walls of the strip (7). For example, it is of course possible to fix the first strands (10) parallel to the strip (7) illustrated in FIG. 1, before folding. It is also possible to fix sets of first strands (10) coupled together, on a front (8) or rear (9) wall of the strip (7) and, after folding, to fix by welding one of the first strands (10) to the other folded wall of the strip (7).

The first strands (10) are therefore fixed to the front (8) and rear (9) walls of the strip (7), facing each other and are intended to be in communication with the interior of the bags (1) packing. For the sake of simplification of Figures 2 and 3, the first strands (10), even if they are located between the two front (8) and rear (9) walls of the strip (7), are not shown in dotted lines.

Still according to the first technique illustrated in Figure 2, the method then comprises a step C consisting in fixing a second strand (11) of complementary coupling means of the hermaphrodite type over the entire width of only one of the two bellows (4) defined by a fold (13) intended to be inserted transversely between the two walls of the strip (7). Indeed, in order to form the gussets (4) of the packaging bags (1), folds (13) of films each defining two gussets (4) folded opposite one another and connected to each other by a longitudinal edge, are inserted transversely and at regular intervals corresponding to the widths of the bags (1) between the front (8) and rear (9) walls of the strip (7), according to a step D.

According to the invention, and in order to be able to perform the function of opening/closing one of the bellows (4) of the bags (1) to form a pouring spout, the second strands (11) are fixed on one only bellows (4) of each fold (13), and are positioned so as to be able to face the first strands (10) after insertion of the folds (13).

The second strands (11) are fixed over the entire width of a bellows (4), that is to say in particular on the two folded flaps of the bellows, and of each folding (13).

In order to form the bag, the method then comprises a step E consisting in welding and cutting the strip (7) transversely between the two gussets (4) of each fold (13) to form the various packaging bags (1). After cutting between the two gussets (4) of each folding (13), one of the gussets (4) is attached to a bag (1), while the other of the gussets (4) is attached to a following bag.

Before or after step E, the method comprises a step, for example F, consisting in welding, see references 14, the openings of each bag (1) and in producing at one of the bellows at least one line of transverse embrittlement (15) adapted to give access to a partial opening (6) for filling after breaking the line of embrittlement. The bag (1) thus obtained is illustrated in Figure 5.

Steps A, B, C, D, E and F of the process according to the invention are given in a certain order, but these can be carried out in a different order, without departing from the scope of the present invention.

For example, steps B and/or C and/or D can be done before step A.

Thus, each first strand (10) is intended to cooperate with possibly the opposite first strand (10), but especially with the second strand (11) of a half bellows, after formation of the bag (1), as illustrated in figure 4. The bag obtained then comprises complementary coupling means of the hermaphrodite type on only one of its bellows (4), and allows the opening/closing of the bag at the level of said bellows (4), according to an opening partial (6) forming a spout.

A second technique of the method according to the invention also makes it possible to obtain the packaging bag illustrated in Figure 4.

According to this technique illustrated in Figure 3, the first strands (10) have a length corresponding to the width of a bellows (4), and are fixed, symmetrically on either side of the transverse lines (12), and alternately every other line (12). Furthermore, the second strand (11) is fixed over the entire width of the two gussets (4) of one fold (13) out of two. This embodiment of the method makes it possible to obtain packaging bags (1) comprising alternately complementary coupling means on a bellows (4) then on an opposite bellows (4).

Whether according to the first technique of Figure 2, or the second technique of Figure 3, and to facilitate the folding of the strip (7) and the bellows (4), the method advantageously comprises an additional step consisting in weakening transversely the first strands (10) and the second strands (11) at areas intended to be folded.

This embrittlement step can be carried out in any appropriate way, and for example by removing the material constituting the first strands (10) and the second strands (11), or by making a weld or pre-cut line on the first strands (10) and second strands (11).

Furthermore, the first strands (10) are fixed discontinuously, and are for example in the form of previously cut sections. These strands (10) can be grasped by a manipulator, deposited, and then welded or for example glued to the front (8) and rear (9) walls of the strip (7).

According to another particular embodiment, the method consists of unrolling the first strands (10), fixing them to the strip (7), then cutting them transversely to the desired length. In this configuration, and according to a particular example, the advance of the strip (7) is stopped for the positioning of a first strand (10), then synchronized with the unwinding of the strand (10), then stopped for the strand cutting operation '10), then restarted at initial speed until the next strand (10) is fixed.

It emerges from the foregoing that the invention indeed makes it possible to provide a method of manufacturing a plurality of packaging bags (1) equipped, at their partial opening (6), with complementary coupling means of the hermaphrodite type for to be able to open and close the bags (1), at will, and by forming a spout.

Claims (8)

Method of manufacturing a plurality of packaging bags (1) each comprising a front wall (2) and a rear wall (3) the side edges of which are connected by gussets (4), a bottom (5), and a partial opening (6) for filling, the method being carried out according to a so-called transverse technique comprising steps consisting, from at least one strip (7) of plastic film unrolled continuously, in:
- Step A: folding the strip (7) lengthwise to define a front wall (2) folded over a rear wall (3);
- step D: insert transversely at regular intervals corresponding to the widths of the bags (1), and between the front (8) and rear (9) walls of the strip (7), folds (13) of film each defining two gussets ( 4) folded facing each other and linked together by a longitudinal edge;
- Step E: welding and cutting the strip (7) transversely between the two gussets (4) of each fold (13) to form the packaging bags (1);
- step F: weld the openings of each bag (1) and make at one of the bellows at least one transverse line of weakness adapted to give access to a partial filling opening (6) after the line of weakness has broken ;
characterized in that before step D, the method comprises steps consisting in:
- step B: attach to each of the front (8) and rear (9) walls of the strip (7) and close to a longitudinal edge of the strip (7), a first strand (10) of coupling means complementary hermaphrodite type, the first strands (10) being intended to face each other when the strip (7) is folded and are fixed longitudinally and discontinuously at regular intervals along the strip (7 ) from each transverse line (12) intended to become the side edge of a bag (1), each first strand (10) has a length corresponding to the dimension of the partial opening (6) and at least to the half the width of a bellows (4);
- step C: fix over the entire width of a single bellows (4) of each bend (13) a second strand (11) of complementary coupling means of the hermaphrodite type, the second strand (11) being positioned to be able, before step E, be placed opposite the first strands (10). Method of manufacturing a plurality of packaging bags (1) each comprising a front wall (2) and a rear wall (3) the side edges of which are connected by gussets (4), a bottom (5), and a partial opening (6) for filling, the method being carried out according to a so-called transverse technique comprising steps consisting, from a strip (7) of plastic film unrolled continuously, in:
- Step A: folding the strip (7) lengthwise to define a front wall (2) folded over a rear wall (3);
- step D: insert transversely at regular intervals corresponding to the widths of the bags (1), and between the front (8) and rear (9) walls of the strip (7), folds (13) of film each defining two gussets ( 4) folded facing each other and linked together by a longitudinal edge;
- Step E: welding and cutting the strip (7) transversely between the two gussets (4) of each fold (13) to form the packaging bags (1);
- step F: weld the openings of each bag (1) and make at one of the bellows (4) at least one transverse weakening line (15) adapted to give access to a partial filling opening (6) after failure of the line of weakness;
characterized in that before step D, the method comprises steps consisting in:
- step B: attach to each of the front (8) and rear (9) walls of the strip (7) and close to a longitudinal edge of the strip (7), a first strand (10) of coupling means complementary hermaphrodite type, the first strands (10) being intended to face each other when the strip (7) is folded and are fixed longitudinally and discontinuously at regular intervals along the strip (7 ) symmetrically on either side of transverse lines (12) each intended to become the side edge of a bag (1), and alternately one line (12) out of two, each first strand (10) has a length corresponding to twice the dimension of the partial opening (6) and at least the width of a bellows (4);
- step C: fix over the entire width of the two bellows (4) of a folding (13) on two a second strand (11) of complementary coupling means of the hermaphrodite type, the second strand (11) being positioned to be able to , before step E, be placed opposite the first strands (10). Method according to Claim 1 or 2, characterized in that it comprises an additional step consisting in transversely weakening the first strands (10) and the second strands (11) at the level of zones intended to be bent. Method according to Claim 3, characterized in that the embrittlement is carried out by removing the material constituting the first strands (10) and the second strands (11). Method according to Claim 3, characterized in that the embrittlement is carried out by producing a weld line on the first strands (10) and second strands (11). Method according to Claim 3, characterized in that the embrittlement is carried out by producing a pre-cut line on the first strands (10) and second strands (11). Method according to claim 1 or 2, characterized in that it consists in fixing the first strands (10) are in the form of previously cut sections. Process according to Claim 1 or 2, characterized in that it consists in unrolling first strands (10), fixing them, then cutting them transversely to the desired length.