EP1073592A1

EP1073592A1 - Packaging film and packaging bag comprising same

Info

Publication number: EP1073592A1
Application number: EP99914639A
Authority: EP
Inventors: Michel Rauturier
Original assignee: Danisco Flexible France
Current assignee: Amcor Flexibles France SAS
Priority date: 1998-04-21
Filing date: 1999-04-21
Publication date: 2001-02-07
Also published as: AU3337799A; FR2777548B1; WO1999054220A1; FR2777548A1

Abstract

The invention concerns a packaging film, comprising at least a flexible film (30, 32), characterised in that it comprises in at least one marked zone, a rigid blank (20) integral over its whole surface with the or each flexible film (30, 32). The invention also concerns a bag produced from such a film.

Description

1

The present invention relates to a packaging sheet of the type comprising at least one flexible film. It also relates to a packaging sachet. The term sachet here designates both a pocket containing a set of separate articles, as well as a folded and sealed envelope around a product, the latter type of packaging being known by the name of horizontal "flow pack".

Many forms of packaging are available for packaging powdered food products, such as ground coffee or flour, or fractionated products such as candy or pasta.

In particular, these products are frequently packaged in packaging bags made from a reel of polymer film. These sachets are produced on packaging machines of the “form fill seal” type which make it possible to simultaneously form, fill and seal the sachet. These sachets can therefore be produced easily and with a reduced manufacturing cost.

However, these bags have a drawback, since they lack stability when placed on a flat surface. In addition, it is difficult to produce parallelepipedal shapes allowing easy and stable stacking of the bags on top of each other.

It is known, in order to remedy these drawbacks, to provide inside the flexible bag a cardboard box containing the products.

A known alternative solution consists, conversely, of having prepackaged products in a sachet, inside a cardboard box.

Such packaging has a very high manufacturing cost and requires the successive installation of two types of packaging produced on two separate machines, on the one hand a cardboard box and on the other hand a flexible bag. The invention aims to provide a packaging sheet allowing the packaging of products in sachets, having good stability, while retaining a low manufacturing cost. To this end, the invention relates to a packaging sheet of the aforementioned type, characterized in that it comprises, in at least one marked area, a rigid blank held integral with the or each flexible film.

According to particular embodiments, the packaging sheet includes one or more of the following characteristics:

- The rigid blank is integral with or each flexible film over its entire surface;

- The rigid blank is self-supporting, when held vertically from its lower end; - It comprises two flexible films joined together, and the rigid blank is sandwiched between the two films;

- the two films are heat-sealable films;

- a layer of adhesive is interposed between each flexible film and the rigid blank; - at least one flexible film is printed on its surface oriented towards the rigid blank;

- It comprises a succession of rigid disjointed blanks, arranged along the length of at least one rigid film to form a packaging strip intended for the manufacture of several packages; - It comprises on at least one flexible film marking marks arranged in zones marked with respect to the rigid blanks;

- The rigid blank is made of one of the materials from flat cardboard, corrugated cardboard, microcannelated cardboard, a polymer or a copolymer loaded or not with mineral matter; and - the rigid blank has at least one crease or perforation line.

The invention further relates to a packaging bag, characterized in that it comprises a sheet according to any one of the preceding claims, the lateral edges of which are folded in the zone comprising the rigid blank and are joined by a longitudinal sealing zone to define the trunk of the bag, which trunk delimits a space for receiving the products to be packaged, the bag comprising two transverse sealing zones for the ends of the sheet on either side of the rigid blank surrounding the products to be packaged, in flexible areas of the sheet devoid of the rigid blank;

According to particular embodiments, the packaging bag has one or more of the following characteristics: - the trunk of the bag is substantially tubular, and in that the creasing lines are parallel to one another along generatrices of the trunk delimiting adjacent sections in the rigid blank.

The invention will be better understood on reading the description which follows, given solely by way of example and made with reference to the drawings, in which:

- Figure 1 is a perspective view of a bag according to the invention, before opening;

- Figure 2 is a perspective view of a bag according to the invention, after opening and partially empty; - Figure 3 is a perspective view of a reel formed of a strip according to the invention intended for the manufacture of the bags shown in Figures 1 and 2;

- Figures 4 and 5 are schematic views of cross sections of the strip of Figure 3 taken, respectively, along lines IV-IV and V-V;

- Figure 6 is a schematic view of a machine for manufacturing the strip of Figure 3;

- Figure 7 is a perspective view of the pressure roller used in the machine of Figure 6; and - Figure 8 is a schematic view of an installation for packaging food products in sachets according to the invention.

The packaging bag shown in FIG. 1 is produced from a composite sheet according to the invention, the side edges of which are folded and are joined by a longitudinal sealing zone 12. The bag also comprises two zones of transverse sealing noted 14, 16. These are arranged at the ends of the sheet on either side of the products to be packaged. In its main part, the bag 10 defines a trunk 18 of substantially parallelepiped shape. This trunk is defined by four adjacent rigid faces denoted 18A, 18B, 18C and 18D. According to the invention, the trunk 18 is delimited by a rigid blank 20, secured over its entire surface to at least one flexible film 32 extending on either side of the trunk 18 to define flexible extensions 24, 26 ending by the transverse sealing zones 14 and 16.

Thus, the current part of the bag, constituted by the trunk 18, defines a rigid tube or sheath for the reception of the products to be packaged, the tube being closed at its two ends by flexible extensions 24 and 26. It can be understood that the bag according to the invention can be placed upright on a horizontal plane resting on the flexible extension 26. The bag is then stable and has a regular geometric configuration due to the rigid trunk 18. After opening the bag in its upper part, as shown in the Figure 2, and after extracting part of the products initially contained in the sachet, it retains its general initial shape, each of the side walls 18A to 18D being self-supporting.

However, extensions 24 and 26 are flexible. Thus, as shown in Figure 2, the flexible extension 24 can be folded into the space defined by the trunk 18 thus improving the visual appearance of the open bag.

In Figure 3, a strip is shown consisting of a continuous succession of packaging sheets according to the invention. The strip is wound to form a reel 28. This strip comprises two flexible films of heat-sealable polymer joined together. The rigid blanks 20 are distributed in zones marked between the two films 30, 32 between which they are enclosed. The film 30 carries laterally printed marking marks 34 delimiting the successive packaging sheets along the length of the strip. Each blank 20 is disposed substantially in the center of the sheet delimited by two successive marks. Thus, the blank 20 is bordered longitudinally on either side by margins 36, 38 consisting of the only flexible films joined together. Likewise, transverse margins 40, 42 are reserved. ves on either side of each blank 18. They are intended to form the flexible sealing extensions 24 and 26.

Each blank 20 has four parallel creasing lines 44A, 44B, 44C, 44D defining five rectangular sections denoted 46A, 46B, 46C, 46D and 46E. The crease lines are oriented along the length of the strip. They can be replaced by aligned perforations or any other treatment ensuring the creation of a line of least resistance of the blank favoring its subsequent folding.

The five panels are intended to constitute the rigid lateral faces of the trunk 18. In particular, the panel 46C has a width greater than that of the other panels. It is intended to form the main face 18A of the bag. The sides 46B and 46D have equal widths and are intended to constitute the side faces 18B and 18D of the bag. Finally, the panels 46A and 46E each have a width equal to half the width of the panel 46C. They are intended to be joined side by side in order to constitute the rear face 18C of the bag.

In FIG. 4, a section of the strip is shown on a larger scale in the zone provided with the rigid blank 20. We find in this figure the blank 20 sandwiched between the heat-sealable flexible films 30 and 32. These are for example polyethylene, polyester, polypropylene, or polyamide films with a thickness of between 12 μm and 100 μm.

The rigid blank 20 is formed for example of a material from flat cardboard, corrugated cardboard, microcannelated cardboard, a polymer or a copolymer loaded or not with mineral matter. Its thickness is adapted so that it is self-supporting, when held vertically from its lower end, considering the greatest length of the blank. In the case of a flat carton, the grammage of the blank is between 150 g / m ² and 500 g / m ² .

The following table indicates, for several grammages of cartons used, the minimum TABER stiffnesses of cartons in the machine direction and in the cross direction to allow the trunk of the bag to keep its shape when the bag is placed vertically. The machine direction is the direction of movement of the tape during the manufacture of the bags. It corresponds to the height of the bag when it is placed vertically. The cross direction is perpendicular to the machine direction and corresponds to a direction perpendicular to the height of the bag.

Minimum TABER rigidity

Weight Machine direction Cross direction

200 g / m ² 65 30

220 g / m ² 80 40

270 g / m ² 120 60

400 g / m 250 120

Preferably, the TABER stiffness of the carton in the machine direction is therefore greater than 65. Advantageously, the grammage of the carton is between 220 g / m ² and 270 g / m ² and the TABER rigidity of the carton in the machine direction is greater to 80.

For a given grammage x of the cardboard, the minimum TABER stiffness y is determined by y = 0.925x - 120. The film 30, intended to form the external face of the sachet, carries on its inner surface a layer of ink 48 intended to identify and decorate the sachet. This ink layer 48 is covered over the entire surface of the film 30 with a layer of adhesive 50.

Likewise, the film 32 intended to form the interior wall of the bag is covered on its internal surface with a layer of adhesive 52.

The adhesive forming the layers 50 and 52 is for example of the crosslinkable type based on polyisocyanate, on hot-melt material, on hot-activatable adhesive or on water-based adhesive.

Thus, the cardboard blank 18 is embedded between the adhesive layers 50, 52 internally covering the films 30 and 32. In the longitudinal margins 36, 38, the films 30, 32 are joined to each other, directly by through the adhesive layers 50, 52 in contact.

In FIG. 5, a section of the strip is shown in an area devoid of rigid blank, for example the transverse margin 40. In this area, the external film 30, associated with the ink layer 48, is associated with the internal film 32 by means of the adhesive layers 50, 52 united in a single film of adhesive extending over the facing surfaces of the two films. 7

In FIG. 6 is shown a machine for manufacturing a strip such as that represented in FIG. 3. This machine is suitable for carrying out the lamination of the two films 30, 32 with insertion of the rigid blanks 20 in marked areas. . The machine of FIG. 6 comprises two reels 60, 62 intended respectively for the continuous feeding of the flexible films 30 and 32,. Downstream of the reel 60, a printing device 64 of the internal surface of the film 30 is arranged. This printing device is intended on the one hand for applying the ink layer 48 and on the other hand for the positioning of the marking marks 34 on the longitudinal edge of the strip in marked zones.

Downstream of the printing device 64 is provided a sizing device 66 intended for placing the adhesive layer 50.

Similarly, downstream from the reel 62, a device 68 is provided for gluing the internal surface of the film 32. This device is intended for placing the adhesive layer 52.

Advantageously, the external film 30 flows horizontally. Downstream of the gluing device 66, a robot 70 is provided for placing rigid blanks 20 previously grooved in identified areas. The robot 70 comprises means for detecting the marking marks 34, in order to position the rigid blanks 20 correctly with respect thereto. In particular, the rigid blanks 20 are distributed regularly over the length of the film 30 between the registration marks 34.

In a variant not shown, the robot 70 is replaced by an adhesive carrying strip continuously conveying the blanks 20 on the film 30 retained on this strip. The carrier strip is brought into contact with the film 30 along a common section so that the blanks adhere to the film 30 through the adhesive layer 50 and thus separate from the carrier strip.

After the inserts 18 have been put in place, the internal film 32 is applied to the blanks 20 and to the glued surface of the film 30. For this purpose, the films 30, 32 pass between two counter-rotating rollers 72, 74 defining a nip between their generators in touch. 8

The upper roller 72, shown on a larger scale in FIG. 7, constitutes a strip forming roller. The roller 74 constitutes a support roller. It is made of rubber and has a smooth, continuous cylindrical surface. On the contrary, the shaping roller 72 is provided with three indentations 76 angularly distributed over the periphery of the roller. These imprints 76 are defined by recesses of constant depth corresponding substantially to the thickness of the rigid blanks 20. The surface of each imprint 76 corresponds to the development of a rigid blank 20 on the external surface of the cylinder 72.

Finally, at the outlet of the rollers 72, 74, the laminating machine comprises a reel 78 intended for shaping the coil 28 shown in FIG. 3.

The machine of FIG. 6 allows the continuous production of a strip such as that shown in FIG. 3.

From two film reels 30, 32, it allows the printing of one of them, as well as the gluing of the surfaces facing the two films. After setting up the rigid blanks 20, the rollers 72, 74 ensure by their rotation in the opposite direction during the circulation of the films 30, 32, in the direction of the arrow F1, the laminating of the films and the joining of the blanks rigid 20 over their entire surface with both of the films. The presence of the imprints 76 on the shaping roller 72 allows the inner film 32 to match the shape of the rigid blanks 20, thus guaranteeing satisfactory bonding of the films against each other in the immediate vicinity of the rigid blanks 20.

In FIG. 8 is shown an installation for packaging food products in sachets according to the invention such as that shown in FIG. 1.

This installation comprises an unwinder 100 on which the reel 28 of FIG. 3 is installed. The latter is arranged with its horizontal axis. At the outlet of the unwinder 100, the strip circulates on turning rollers

102. It is then deformed around a shaper 104. The latter is formed by a frustoconical wall internally defining a funnel 106 of introduction of the products to be packaged. The former 106 is extended downwards a tubular duct of rectangular section 108 around which the lateral edges of the strip are folded.

In particular, each of the panels 46A to 46E is applied against a lateral surface of the conduit 108. The crease lines 44A to 44D are applied along the edges of the conduit 108 to cause the blank 20 to be shaped. The lateral margins 36, 38 are applied respectively to the inside and outside of the trunk 18 between sections 46E and 46A respectively. Next to the overlapping area of the margins 36, 38 is installed a heating sealing iron 110. This is associated with jacks 112 intended to ensure an alternating movement of the sealing iron from a retracted position, represented in FIG. 8 , to a welding position, the iron then being in contact with the folded edges of the strip and pressing them against the tube 108 to perform the longitudinal weld 12. Immediately at the outlet of the tube 108, two jaws are arranged transversely oscillating sealing 114. These jaws are heated and are suitable for simultaneously carrying out transverse seals 14 and 16 of two successive sachets. The jaws 114 are mounted movable in a plane perpendicular to the axis of the tube 108. They are movable between a position spaced from one another allowing the passage of a bag and a welding position where the jaws are applied l one against the other substantially along the median longitudinal plane of the tube 108.

Below the jaws 114 is arranged a conveyor 116 for receiving the sealed bags. On the conveyor 116 is provided a pressing member 118 movable vertically under the like of a jack 120. The pressing member 118 is adapted to fold the flexible extension 26 in order to ensure the plating of the lower transverse seal 16 against the surface bottom of the bag. The conditioning system operates as follows.

The coil 28 is progressively unwound step by step in the direction of the arrow F2. It flows successively around the shaper 104 and the conduit 108 until it defines a tube. The sealing iron 110 ensures the realization 10 tion of the longitudinal weld 12. Sequentially, the funnel 106 is loaded with the contents of a sachet. By gravity, the products fall to the bottom of the tube closed by the sealing zone 14. While the jaws 114 are separated, the strip is then advanced by a step whose length corresponds to the height of a sachet. The jaws are then brought together to enclose the flexible section of the tube defined between the two successive rigid blanks. The jaws 114 thus simultaneously form the transverse sealing zone 16 of the previously filled bag and the upper transverse sealing zone 14 of the following bag. They simultaneously ensure the sectioning between the two consecutive sachets, which allows the lower sealed sachet to fall under the action of its own weight.

The sealed bags are transported on the conveyor 116. Passing under the pressing member 118, they have their lower flexible extension 26 folded down. Advantageously, the flexible extension 26 of each sachet is secured to the base of the trunk 18, for example by a heating iron applied to it downstream of the pressing member 118.

The manufacture of such a packaging sachet can be carried out on a conventional machine for manufacturing sachets, without it being necessary to make substantial modifications. In addition, the rigid structure being integrated in the flexible film, a single packaging operation is sufficient to obtain a stable packaging that can be stacked.

Likewise, a packaging sheet according to the invention can be implemented in packaging of the horizontal “flow pack” type. This type of packaging is intended to receive rigid products, such as a chocolate bar.

The packaging then consists of a sheet folded around the product. The sheet is longitudinally sealed by a longitudinal sealing area. The tube thus formed is closed at each end by transverse sealing zones. Such packaging is produced from a horizontally circulating strip on which the products to be packaged are deposited at regular intervals. The strip is folded around the products, the side edges being sealed one on the other in the upper part of the product. In 1 1 in this case, the rigid blank contained in the sheet defines a protective sheath for the packaged product.

In addition, in the embodiment described here, the longitudinal sealing zone is produced by bringing into contact and sealing the opposing surfaces of the sheet with overlapping thereof. Thus, the longitudinal sealing area is of the “flesh against leather” type.

As a variant, the two longitudinal edges of the sheet can be folded over one another so that these are applied against one another along the inner surface of the sheet. The longitudinal sealing area is then of the “flesh for flesh” type. This type of longitudinal sealing is carried out by any known type of suitable machine.

Although the packaging sheets described here are presented in the form of strips comprising several sheets arranged in succession, the packaging sheets can be separate and constitute formats, each suitable for packaging.

In the embodiment described, the blank is secured over its entire surface to the internal and external flexible films. In a variant not shown, the blank can be held integral between the two films without being directly attached thereto. The two films are then for example joined to one another at the periphery of the blank, so that the blank is retained sandwiched between the two films, without however being glued to one or the other of the films.

The assembly of the packaging sheet, and in particular the joining of the blank with each flexible film can be achieved by any suitable technique, and in particular by lamination extrusion, by hot calendering, by ultrasonic welding, or by lamination extrusion, followed by hot calendaring.

The presence of a rigid trunk delimiting the structure of the packaging makes it possible to define flat and rigid lateral surfaces on the packaging, which promotes the readability and the clarity of the inscriptions carried on the packaging. Finally, the packaging described here is of substantially parallelepiped shape. However, any other shape can be envisaged, in particular a cylindrical trunk of circular section.

Claims

12

CLAIMS 1.- Sachet packaging made from a packaging sheet comprising at least one flexible film (30, 32) and, in a marked area, at least one blank (20) held integral with the or each film flexible (30, 32), characterized in that it comprises a single rigid blank, which rigid blank (20) is bordered longitudinally and transversely, on both sides, by flexible lateral margins (36, 38) and flexible transverse margins (40, 42), and in that the lateral margins (36, 38) are folded in the marked area comprising the rigid blank (20) and are joined by a longitudinal sealing area (12) to define a trunk (18) of the bag, which trunk is delimited by said rigid blank (20) and defines a rigid tube which delimits a space for receiving the products to be packaged, the bag comprising two transverse sealing zones for the ends of the sheet , arranged in the flexible transverse margins (40, 42) of the a sheet on either side of the rigid tube defined by the blank (20) surrounding the products to be packaged.

2. A packaging bag according to claim 1, characterized in that the rigid blank (20) is integral with the or each flexible film (30,32) over its entire surface.

3. A packaging bag according to claim 1 or 2, characterized in that the rigid blank (20) is self-supporting, when held vertically from its lower end.

4. A packaging bag according to any one of the preceding claims, characterized in that the packaging sheet comprises two adjoining flexible films (30, 32), and in that the rigid blank (18) is sandwiched between the two films (30, 32).

5. A packaging bag according to claim 4, characterized in that the two films are heat-sealable films.

6. A packaging bag according to claim 4 or 5, characterized in that a layer of adhesive (50, 52) is interposed between each flexible film (30, 32) and the rigid blank (20).

7. A packaging bag according to any one of the preceding claims, characterized in that at least one flexible film (30) is printed on its surface oriented towards the rigid blank (20). 13

8. A packaging bag according to any one of the preceding claims, characterized in that the rigid blank (20) is made of one of the materials from flat cardboard, corrugated cardboard, microcannelated cardboard, a polymer or a copolymer loaded or not with mineral matter.

9. A packaging bag according to any one of claims 3 and 8, characterized in that the blank is made of flat cardboard and the TABER stiffness of the cardboard in the direction of the height of the bag is greater than 65.

10. A packaging bag according to claim 9, characterized in that the TABER stiffness of the carton in the direction of the height of the bag is greater than a minimum value y given by y = 0.925x - 120 where x is the grammage of the carton in g / m ² .

11. A packaging bag according to any one of the preceding claims, characterized in that the rigid blank (20) comprises at least one creasing line (44A, 44B, 44C, 44D) or of perforation.

12. A packaging bag according to claim 11, characterized in that the trunk of the bag (18) is substantially tubular, and in that the creasing lines (44A, 44B, 44C, 44D) are parallel to each other. along generatrices of the trunk (18) delimiting adjacent sections (46A, 46B, 46C, 46D, 46E) in the rigid blank (20).