EP0142455A2 - Bag of synthetic flexible material having a tab of heat-sealable foil to open it - Google Patents

Abstract

1. Sachet of flexible synthetic material of the type obtained by suitable folding of a single film of synthetic material, or from two strips of film, and welds forming the different sides of the sachet, comprising, along one weld line and in line with the region of the sachet where the pouring opening must be formed, at least one narrow strip of a bilateral thermo-sealing film interposed between the two film thicknesses connected by the said weld line, characterised in that the narrow strips (16) possess in their central part a curvilinear section possessing a high point (17) outside the weld line.

Description

The subject of the present invention is a bag of flexible synthetic material of the type obtained by adequate folding of a single film of synthetic material, or from two strips of film, and welds determining the different sides of the bag. It also relates to a process for obtaining it.

Sachets of this type are well known. They were for example, and not limited to, the subject of French patent applications 75-18358, 78-04233 and 80-02187 in the name of the applicant.

They can be obtained by multiple methods, which essentially fall into two categories, depending on whether the path of the film and of the bags thus formed is horizontal or vertical.

A horizontal type shaping machine is described for example in French patent application 80-02187 in the name of the applicant.

A vertical type shaping machine is described for example in French patent 71-20879.

In what follows, reference will be made to a process of the "vertical" type, but it will be understood that the invention should not be limited neither to the processes of this type, nor to the modes of implementation described in the aforementioned patents.

Bags of synthetic material of this type have been the subject of numerous developments and researches essentially focused on the problems of gripping on the one hand and stability in vertical position on the other hand, independently of course of researches as to the nature of the film itself.

Sachets of this type, intended in particular for packaging beverages or spring water, are however designed to condition a volume of liquid of one liter or more.

It is therefore imperative that they can be opened easily, but above all in a manner allowing use multiple of the sachet. Cutting the bag to allow the pouring of its contents must therefore be able to be carried out by the user correctly, regardless of the user.

In existing sachets, the cutting is carried out essentially by scissors, which therefore does not eliminate the risk of random cuts poorly performed. It is thus necessary to have on hand any means to open the bag, which is impractical during outdoor use (hiking for example).

There is therefore a need for sachets of the type described above which are provided with the manufacture of opening means ensuring on the one hand an easy manual opening and on the other hand a perfectly localized opening.

According to the invention, this result is obtained with a flexible plastic bag of the type obtained by adequate folding of a single film of synthetic material, or from two strips of film, and welds determining the different sides of the bag, characterized in that it comprises, along a weld line and at the point of the bag where the pouring opening is to be determined, at least one strip of a two-sided heat-sealing film interposed between the two thicknesses dufilm connected by said weld line.

The strip of heat-sealing film can be inserted into a vertical seal (vertical side of the bag), horizontal (upper edge of the bag) or overlap - on two welds, vertical and horizontal, in an upper corner of the bag.

Thus, in accordance with the invention, a preferential peel-off zone is determined, consisting of the heat-sealed portion which can be easily peeled by the user, without however calling into question the strength and hygiene properties of the sachet.

The heat-sealing film may for example consist of an adhesive varnish placed on each side of a aluminum or other support, the varnish disposed on each of the faces possibly being of a different nature. The film must of course be food grade.

According to an advantageous embodiment of the invention, the sachet will comprise two strips of two-sided heat-sealing film arranged opposite. The opening is thus further facilitated, due to the symmetry.

The film strips can be linear or else assign a curvilinear cut to their central part to facilitate peeling.

According to another alternative embodiment of the invention, the bag will include, near the opening area, a reversible adhesive which will allow the bag to be closed after a first use.

• - la figure 1 est une vue schématique de la mise en oeuvre du procédé de l'invention sur machine à cheminement vertical,
• - la figure 2 illustre un sachet conforme à l'invention avec film thermoscellant biface unique sur ligne de soudure horizontale,
• - la figure 3 illustre un sachet conforme à l'invention avec double film thermoscellant biface sur ligne de soudure horizontale,
• - la figure 4 illustre un sachet conforme à l'invention avec film thermoscellant à découpe curviligne,
• - la figure 5 illustre un sachet conforme à l'invention avec film thermoscellant biface unique sur ligne de soudure verticale,
• - la figure 6 illustre un sachet conforme à l'inven- avec double film thermoscellant biface sur ligne de soudure verticale,
• - la figure 7 illustre un sachet conforme à l'invention avec film thermoscellant en coin,
• - la figure 8a illustre un sachet conforme à l'invention avec adhésif reversible, en position d'ouverture,
• - la figure 8b est la même vue que 8a, en position de fermeture.

The invention will be better understood using the description below made with reference to the appended drawings in which:

• FIG. 1 is a schematic view of the implementation of the method of the invention on a machine with vertical tracking,
• FIG. 2 illustrates a bag in accordance with the invention with a two-sided heat-sealing film on a horizontal weld line,
• FIG. 3 illustrates a bag in accordance with the invention with a double sided heat-sealing film on a horizontal welding line,
• FIG. 4 illustrates a bag according to the invention with a heat-sealing film with a curvilinear cut,
• FIG. 5 illustrates a bag in accordance with the invention with a single two-sided heat-sealing film on a vertical welding line,
• FIG. 6 illustrates a sachet in accordance with the invention with a double sided heat-sealing film on a vertical welding line,
• FIG. 7 illustrates a bag in accordance with the invention with a corner heat-sealing film,
• FIG. 8a illustrates a bag according to the invention with reversible adhesive, in the open position,
• - Figure 8b is the same view as 8a, in the closed position.

Reference will first be made to FIG. 1, recalling that the invention is in no way limited to implementation on a machine with vertical tracking.

On a machine of this type, a film (1) is wound on a mandrel (2) for forming and filling the individual bags formed after vertical sealing and bottom sealing.

The vertical welding is carried out in itself well known manner, by a welding device such as (3), the intermittent operation of which is linked to the device for advancing the film downwards, itself produced by belts from a drive motor.

A sheath (4) is thus obtained, the bottom of which is welded together with the upper edge of the following bag, thanks to a horizontal welding device (5). The cutting is carried out between the two welds by a mechanical cutting station (6).

According to the invention, there is interposed between the two ends of the film which overlap at the level of the vertical weld a strip (7) of the heat-sealing film which is supplied from a reel (8) which takes place step by step under the action of a drive motor. A cutting station (9) makes it possible to cut the strip at the vertical weld. The strip being thus inserted between the two ends of the film, the weld secures them.

We arrive from there at the configurations which are illustrated in Figures 2 to 7.

In Figure 2, the welding was carried out with a coil and a rectilinear welding device. The heat-sealing film (10) is, as indicated above, pinched in the vertical weld (11) produced by the station (3). At the welding station (5), we welded horizontally to the strip (10). The cut made at the horizontal cutting station, between the two sealing bars (5) leaves two free walls (12, 13) between which the film (10) projects. The opening is done by peeling at this level.

In Figure 3, there is shown the same case as in Figure 2, a double strip (14,15) interposed in the same way on horizontal weld. In both cases, the strip or strips are pinched between the horizontal (10) and vertical (11) welds.

The two strips are inserted in the same way as one, from two reels such as (8), with two driving devices. The two strips can also be supplied from the same suitable coil.

The application of the welding heat at the level of the strips (10, 14, 15) causes the heat sealing of this zone on the facing portions, film or other strip.

In FIG. 4, a variant is shown in which the strip (s) (16) have a high point (17) outside the weld line, which ensures even greater reliability in terms of the precision of the opening. . Such a strip can be placed on a horizontal or vertical weld.

In the embodiments of FIGS. 5 and 6, the strips are on vertical weld, the horizontal weld taking place above said strips. The opening and therefore the pouring are done on a vertical edge of the bag.

In the variant of FIG. 7, the strip or strips (18) will be at the junction of a vertical weld line (19) and a horizontal line (20). The peeling will therefore be done in the upper corner of the sachet opposite the handle, if it has one.

Advantageously, as shown in FIGS. 8a and 8b, there will be placed near the strips (10,14,15,18) a reversible adhesive (21) which makes it possible to obtain a closure. reversible security, after first use of the bag. To do this, the grip edges of the strip (s) are folded against one of the walls so as to close the opening, and they are immobilized in this position thanks to the reversible adhesive, as illustrated in FIG. 8b.

It will be understood that multiple variants can be envisaged, within the reach of those skilled in the art, without departing from the scope of the invention.

Claims (9)

1. Bag of flexible synthetic material of the type obtained by adequate folding of a single film of synthetic material, or from two strips of film, and welds determining the different sides of the bag, characterized in that it comprises, along at least one strip (10) of a two-sided heat-sealing film inserted between the two thicknesses of film connected by said line of welding line and at the location of the sachet where the pouring opening is to be determined welding. 2. Bag according to claim 1, characterized in that the strip is on a horizontal weld. 3. Bag according to claim 1, characterized in that the strip is on a vertical weld. 4. Bag according to claim 1, characterized in that the strip (18) is both on a horizontal weld (20) and on a vertical weld (19). 5. Bag according to any one of claims 1 to 4, characterized in that it comprises two strips (14,15) arranged opposite one another. 6. Bag according to any one of claims 1 to 5, characterized in that the strips (10; 14,15; 18) are rectilinear. 7. Bag according to any one of claims 1 to 5, characterized in that the strips (16) have at their central part a curvilinear section having a high point (17) outside the weld line. 8. Bag according to any one of claims 1 to 7, characterized in that it comprises, near the opening area, a reversible closure adhesive (21). 9. Method for producing a sachet according to any one of claims 1 to 8, characterized in that it consists, during the welding between two thicknesses of film determining at least one of the edges forming the corner of pouring the sachet, to insert between these two thicknesses at least one strip of a two-sided heat-sealing film.

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