HK1058925B - Sealed beverage container and method thereof - Google Patents

Description

Sealed beverage container and method of making same

Technical Field

The present invention relates to sealed packages of pourable food products and to a related manufacturing method.

Background

Many pourable food products, such as fruit juice, UHT milk, wine, tomato sauce, etc., are sold in packages made of sterile packaging material.

A typical example of such a package is a square package for packaging liquid or pourable food products, known as Tetra Brik or Tetra Brik Aseptic (registered trademark) package, which is formed by folding and sealing a layer of the web packaging material. Such packaging material has a multilayer structure comprising a layer of fibrous material, for example paper, covered on both sides with layers of heat-seal plastic material, for example polyethylene, and, in the case of aseptic packages for long-storage food products, for example UHT milk, a layer of barrier material, consisting for example of an aluminium film, which is superimposed on a layer of heat-seal plastic material, and is then covered with another layer of heat-seal plastic material eventually defining the inner face of the package contacting the food product.

It is known that such boxes can be manufactured with fully automated packaging units. On such devices, the web-fed packaging material is formed into a continuous tubular member; the web of packaging material is then sterilized, for example with a chemical sterilizing agent such as a hydrogen peroxide solution, immediately on the packaging unit itself, which sterilizing agent, after sterilization, is removed from the surface of the packaging material, for example by means of heat evaporation, and the web of packaging material thus sterilized is then kept in a sterile environment and folded and sealed in the longitudinal direction to form a vertical tubular element.

The sterilized and sterile-processed food product is continuously injected into the tubular member from the top, then sealed and cut transversely equidistantly to form pillow-shaped packages, which are then mechanically folded to form the final, e.g. substantially square, package.

Alternatively, the packaging material is cut into blanks, which are then formed into packages on forming spindles, and the final packages are filled with the food product and sealed. An example of such a package is commonly referred to as a so-called "gable-top" package, designated by the trade name Tetra Rex (registered trade mark).

The above packages usually have sealable opening devices to allow consumption of the food product in the package and to prevent foreign objects from coming into contact with the food product.

Opening devices commonly used today comprise a frame defining an opening and fitted over a hole in the top wall of the package, or over a pierceable or removable portion. The opening device further comprises a lid which can be hinged or screwed onto the frame, and which can be removed to open the package. It is also known to use other opening devices, for example of the sliding type.

Regardless of the type of opening device used, the top wall of a packaging container formed from a tube of packaging material is provided with a number of sealing bands which limit the space available for mounting the opening device on the top wall. In particular, a flat transverse sealing strip spans the top wall along a central line, the sealing strip being folded down over the top wall and coplanar with the top wall; a flat longitudinal sealing band, the end of which crosses the top wall along the centre line and is coplanar with the top wall, extends perpendicularly to the transverse sealing bands. More specifically, the longitudinal sealing strip extends along a portion of the top wall of the package and folds down from the top wall and extends along the side and bottom walls of the package.

Likewise, the uniaxially formed package also includes a top wall across which is spanned along a center line a flat transverse sealing band folded down over and coplanar with the top wall.

In either case, the opening device cannot be mounted on the sealing band of the package. This not only causes problems in sealing the opening device against uneven surfaces, but also compromises the integrity of the seal itself.

The opening device can therefore be applied only to a limited flat portion close to the sealing band across the top wall of the package, which limits the maximum size of the opening device.

The above-mentioned drawbacks are particularly pronounced due to the increasing number of food products of different physical forms sold in paper packaging material packages. Some of these foods, particularly semi-fluid foods or foods containing fibers or particles, require a large opening device to allow smooth injection of the food.

In order to increase the space for mounting the opening device on the package, it has been proposed to reverse the direction in which the transverse sealing band is folded onto the top wall, folding it onto the side of the longitudinal sealing band. The additional space obtained with this method is however rather small.

Another proposed solution is to form the front edge of the top wall of the package with a convex C-shaped crease line or so-called "crease line" preformed in the packaging material and projecting outwards of the package.

This solution ensures a greater space for the installation of the opening devices than is obtained by reverse folding of the transverse sealing band. There is therefore a need in the industry for further improvements, and in particular for new solutions to be proposed, in order to further increase the space required to form larger openings in packages.

Disclosure of Invention

It is an object of the present invention to provide a sealed package for pourable food products, designed to directly solve the above-mentioned drawbacks associated with existing packages.

In accordance with the present invention, a sealed package for a pourable food product is provided. The package is made of a web of packaging material, comprising a top wall and an opening device, across which is spanned at least one transverse sealing band forming a flat projecting tab folded along a bending line coplanar with and onto the top wall, the opening device being fitted on a portion of the top wall bounded on one side by said sealing band; the sheet comprises a flat strip-shaped auxiliary portion located between the sealing band and the bending line, the width of the auxiliary portion being such as to increase the area of the portion of the top wall available for the opening device.

The invention also relates to a method for manufacturing sealed packages for pourable food products from a sheet of packaging material, said method comprising the steps of:

forming a box-shaped member which is open at the top and filled with the food;

forming a top wall for closing the box-shaped element, across which is spanned at least one transverse sealing band forming a flat projecting tab delimiting on one side a portion of the top wall available for accommodating the opening device;

folding the sheet so as to be coplanar with the top wall and on the top wall along a bending line previously formed on the packaging material;

characterized in that the step of forming the top wall is: the top of the box-shaped element is sealed at a predetermined distance (Z) from the bend line on the packaging material, so that, when folded, the sheet comprises a flat strip-shaped auxiliary portion between the bend line and the sealing band, the width of which portion increases the area of the portion of the top wall available for receiving the opening device.

Drawings

Two preferred non-limiting embodiments of the invention are described below by way of example with reference to the accompanying drawings. These figures are:

fig. 1 is a perspective view illustrating a sealed package for a pourable food product, made in accordance with the present invention;

FIG. 2 is a reduced bottom view illustrating the package shown in FIG. 1;

fig. 3 is a front view of the packaging machine making the packages of fig. 1 and 2, with parts broken away for clarity;

FIG. 4 is a schematic side view showing the forming unit of the machine shown in FIG. 3;

FIG. 5 shows a portion of the packaging material formed on the machine of FIG. 3;

fig. 6 is a perspective view showing another embodiment sealed package for a pourable food product, made in accordance with the present invention.

Detailed Description

Reference numeral 1 in figures 1 and 2 indicates as a whole a sealed package for pourable food products, made from a sheet of packaging material according to the present invention.

The packaging material is of multilayer structure (not shown) comprising a layer of fibrous material, usually paper, covered on both sides by respective layers of heat-seal plastic material, e.g. polyethylene, and, in the case of long-storage food products, e.g. aseptic packages for storage of UHT milk, a layer of barrier material, e.g. aluminium, covered with one or more layers of heat-seal plastic material, on the side of the packaging material that comes into final contact with the food product in package 1.

The package 1 is a square body, formed by two opposite respective front and rear walls 2 and 3, two opposite side walls 4 and 5 perpendicular to the front and rear walls 2 and 3, and two respective top and bottom walls 6 and 7 perpendicular to the walls 2, 3, 4 and 5.

The package 1 further comprises a closable opening device 8 mounted on the top wall 6.

In the example shown, the opening device 8 is of the type described in italian patent application n.t099a000726 filed by the inventor hereof, and it substantially comprises a circular frame (not shown in the drawings) arranged around the pierceable portion 9 (fig. 5) of the wall 6, and a screw cap 10 screwed onto the frame. According to the method described in the european patent application NO 99830533.8 filed by the present inventor, the screw cap 10 is fixed to the pierceable portion 9 or directly sealed thereto, so that when the sealed package 1 is to be opened, the pierceable portion 9 is detached from the rest of the packaging material by rotating the screw cap 10.

The portion 9 which can be perforated is constituted by a so-called "pre-laminated" hole 11 (figure 5) in the package 1, i.e. the hole is made in the fibres of the packaging material, which is then covered with a layer of barrier material which can close the hole hermetically and aseptically, while being easily perforated.

Alternatively, package 1 may have different opening devices, for example of the type proposed by the inventors in european patent applications nos. 99830621.1 and 99830622.9, which also comprise a frame and a screw cap similar to those described above, and perforating means housed in the frame and driven by the screw cap so as to perforate holes 41 previously formed in the packaging material by the web.

The package 1 may also be provided with an opening device of the kind described and shown, for example, in international patent application WO98/18684, which opening device is formed by injection moulding plastic directly in a through-hole in a sheet of packing material before the packing material is formed into a package.

Package 1 comprises respective two top and bottom flat transverse sealing bands 15 and 16, which extend through respective walls 6 and 7 and are parallel to walls 2 and 3.

The band 15 divides the wall 6 into two portions 17 and 18, one of which is adjacent to the wall 2, forming a portion for mounting the opening device 8, and the other portion 18 is adjacent to the wall 3, comprising the end portion of a flat longitudinal band 19 of the package 1 substantially along the centre line. In particular, sealing band 19 extends vertically between sealing bands 15 and 16 and along the centerline of wall 3.

The sealing band 15 extends beyond the wall 6 of the package 1 onto the side walls 4 and 5 and forms, together with the walls 4, 5, 6, respective flat, substantially triangular or trapezoidal side portions 20 of the packaging material, which are folded from the wall 6 to be coplanar with the respective walls 4 and 5 and are folded onto the respective walls 4 and 5.

The sealing band 15 is formed lengthwise with a flat top sheet 21 projecting from the portions 17 and 18 of the wall 6 and from the side portions 20 and folded over the portions 18 and 20 along a fold line 22 formed on the bottom of the sheet 21. In particular, the bending line 22 comprises a main portion 22a formed along the wall 6 of the box, along which only one side of the portion 18 on which the tab 21 is folded is formed along the wall 6 of the wrapper 1, and opposite end portions 22a and 22c formed on either side of the respective side portions 20.

According to an important aspect of the invention, sheet 21 comprises a flat strip-shaped auxiliary portion 25 between sealing band 15 and fold line 22, or in other words between sealing band 15 and the packaging material eventually forming package wall 6, so that the portion of wall 6 for mounting opening device 8 increases the width of auxiliary portion 25. It is thus possible to receive an opening device 8 which is larger than the opening devices of the known packages.

Thus, the area of the wall portion 17 receiving the opening device 8 is larger than the area of the wall portion 18.

With reference to figure 2, as in wall 6, band 16 extends beyond wall 7 of package 1, to walls 4 and 5 on both sides, and forms, together with walls 4, 5, 7, a respective flat, substantially triangular bottom portion 26 of the packaging material, which is folded from respective walls 4 and 5 to be coplanar with wall 7, and onto wall 7.

The sealing strip 16 is formed lengthwise into a flat base sheet 27 which projects beyond the wall 7 and is folded to be coplanar with the wall 7 and onto the wall 7, and an underlying base portion 26 which follows the fold line 28 formed in the base portion of the sheet 27.

Reference numeral 30 in fig. 3 designates as a whole a packaging machine which produces continuous packages 1 from a tube 31 of packaging material, which tube 31 is formed by folding and sealing a web 32 of packaging material longitudinally.

The web 32 comprises a series of pierceable portions 9 (figure 5), which in the example shown are constituted by holes 11 previously covered with a sheet, the pierceable portions being equally spaced apart by a distance equal to the length of the web portion 32 required to form one package 1.

Along the layer of fibrous material, the web 32 also comprises a series of weakening lines and lines of folding, with which the packaging material can be easily bent when formed. These lines of weakness are equally spaced along the web 32 with the same spacing as between the pierceable portions 9. Which forms, for example, the edges of walls 2-7 and portions 20 and 26 of the final package 1, and in particular comprises fold lines 22, 28 of sheets 21, 27 of package 1.

The web 32 of packaging material is withdrawn from a reel (not shown) and fed from a known sterilizing unit (not shown) by means of a known guide roller arrangement (not shown) to a top aseptic chamber 33 of the machine 30, which aseptic chamber 33 is in communication with the sterilizing unit, through which aseptic chamber the web 32 passes horizontally. The web 32 is then diverted downwardly by driven folding rollers 34 to pass down a vertical path P extending within a vertical chamber or tower 35.

Inside tower 35, web 32 is folded into a cylinder about an axis a parallel to path P, forming tube 31, which is heat-sealed longitudinally by known heat-sealing devices 36 (not shown in detail), forming longitudinal sealing strips from which longitudinal sealing bands 19 of packages 1 are finally derived. The tube 31 is then filled continuously from the top with the food product by means of a known filling device 31 (not described in detail) and is conveyed to a forming unit 38, which forming unit 38 will be described below only with respect to the parts relevant to the invention.

In particular, the packaging machine 30 comprises a folding unit 39 which can fold the web 32 longitudinally to form the tube 31. The folding unit is constituted by a number of known folding assemblies 40 and 41, 42 arranged inside the tower 35 along the path P. These folding assemblies interact with the web 32 and can fold it, progressively forming a cylinder, and partially overlapping opposite sides of the web 32, forming a tube 31 of packaging material.

The folding assemblies 40, 41, 42 comprise generally cylindrical folding rollers 43, 44 and 45 having respective axes perpendicular to the axis a and forming a continuous polygon enclosing this axis a, so that the respective side surfaces form a continuous channel forced through the web of packaging material 32 during the forming step. As the sheet 32 passes through the passageway, it is deformed from the opened C formed by the rollers 43 of the assembly 40 into a generally circular shape formed by the folding rollers 45 of the assembly 42.

The speed at which the web 32 passes through the assemblies 40, 41, 42 is controlled by a motor 46 which drives the folding cylinder 34.

Once longitudinally sealed, the tube 31 is conveyed to a forming unit 38.

The unit 38 comprises a support member 47 defining two vertical guides arranged symmetrically with respect to a vertical longitudinal median plane B of the unit 38 passing through the axis a. The respective axes of the vertical guides 48 lie on the transverse vertical median plane C of the unit 38. Thus, axis a is the intersection of planes B and C.

Unit 38 comprises, in a known manner, two forming assemblies 50, 50' movable along respective guides 48, which can interact alternately with tube 31 of packaging material, grip tube 31 and heat-seal its cross-section to form continuous longitudinal sealing bands 15 and 16 of final package 1.

Since the components 50, 50' are symmetrical with respect to the plane B, only one component (component 50) is shown in detail in fig. 4 and described below. In fig. 3 and 4, corresponding parts of the assemblies 50, 50' are designated by the same reference numerals.

The assembly 50 basically comprises a slide 51 movable along the respective guide 48 and two jaws 52 hinged at the bottom of the slide 51 and rotatable about respective horizontal axes E, parallel to the plane C, with respect to which they are symmetrically arranged, in order to open and close like a book.

In particular, each jaw 52 comprises a control body 53, which is a substantially square plate, extends along a working plane D of the jaw 52 containing the respective axis E, is hinged in a position close to the bottom side of the jaw 51, and comprises a respective control arm 54, which projects from a side of the body 53 facing away from the plane D.

The jaws 52 also comprise respective support arms 55 (fig. 3) mounted on the respective body 53 of the respective jaw 52 at both ends thereof and extending, in respective directions parallel to the respective axis E, substantially along the respective working plane D towards and beyond the plane D, so as to be disposed on opposite sides of the tube 31.

The projecting portion of the arm 55 is equipped with a respective sealing member 56, 57 (figure 4) in the form of a rod, which can interact with the tube 31 and is formed, for example, by an inductor for generating an induced current in the aluminium layer of the packaging material, against which the tube 31 is crimped with the required pressure, by means of the joule effect of the induced current and a matching pad on which the heat-seal plastic layer can be melted.

A pair of vertical rods (not illustrated) are used in a known manner (not illustrated) to control the reciprocating movement of the control slider 51 and the on/off movement of the gripping head 52, which in turn are controlled by a rotary cam or servomotor.

The jaws 52 are movable between a closed position in which the respective sealing members 56, 57 grip the tube 31 and a fully open position.

During the transverse sealing step, the tube 31 is heat-sealed along two parallel adjacent transverse sealing bands by the sealing members 56, 57 of each forming assembly 50, 50'. Which constitute respectively the top transverse sealing band 15 and the bottom transverse sealing band 16 of package 1 of the detaching unit 38 and thus constitute respectively the top sheet 21 and the bottom sheet 27.

In particular, a seal 1 is formed (fig. 5), first the bottom sealing band is formed, thus obtaining an open-top box-shaped element 60, and then the top sealing band 15 is formed, constituting a closed box-shaped element 60.

The arms 55 of the jaws 52 support, above the respective sealing members 56, 57, respective pack volume control flaps 65 having a C-shaped cross section open at the front end, able to cooperate with each other to form, after the transverse sealing operation with the sealing members 56, 57, a cavity of predetermined shape and closed volume, so as to shape the tube 31 in a rectangular shape.

The above-described forming step (fig. 5) forms pillow-shaped modules 61, each module comprising: a main portion 62 having the same shape and volume as the final portion of the packaging formed by the walls 2, 3, 4 and 5; first and second transition portions 63, 64 connecting the main portion 62 to the topsheet 21 and the backsheet 27, respectively, and projecting laterally from the main portion 62.

In particular, folding the transition portion 63 of each pillow 61 results in the top wall 6 and the side portions 20 of the respective package 1, and folding the transition portion 64 results in the bottom wall 7 and the bottom portion 26 of the package 1.

By means of the enclosing members 56, 57 of each forming assembly 50, 50', it is possible to form each transverse seal of the tube 31, which is separated by a predetermined distance Z from the respective underlying fold line 22 preformed on the web 32 of packaging material, so as to leave an auxiliary portion 25 of packaging material between the top sealing band 15 of each pillow-like member 61 and the respective fold line 22 of the sheet 21 formed by this band 15, which, as mentioned above, increases the space available for mounting the respective opening devices 8 on the wall 6 of each package 1.

After transverse sealing, the tube 31 is conveyed along path P from the forming unit 38 to a known cutting unit (not shown) located downstream, which separates the pillow assemblies 61 along a cutting line T (schematically shown in broken lines in fig. 5) between adjacent transverse sealing bands 15, 16.

Fig. 6 shows the basic principle of the present invention applied to packages commonly referred to as "Tetra prism" and "Tetra prism aseptic" (registered trademark). The package is designated as a whole by 1'. In the following description, the package 1' is described only for parts other than the package 1, and the same reference numerals are given to those parts similar to the already described parts.

In particular, package 1' differs from package 1 in that the front, rear and side walls 2, 3, 4, 5 are connected to each other with an inclined intermediate portion 70, while the top wall 6 is inclined and forms, together with wall 2, a projecting C-shaped front edge 71, or "upturned bend line" 71, which projects outwards.

More specifically, bottom wall 7 is flat and rectangular, while opposite wall 6 is formed by respective straight side edges 68 close to walls 4 and 5, by a front edge 71 close to wall 2 and by a straight rear edge 69 perpendicular to edge 68 close to wall 3.

The inclined intermediate portion 70 tapers towards the walls 6 and 7. And diverge at the apex of the walls 6 and 7.

The edge 71 forms a portion 17 of the wall 6 on the opposite side of the sealing band, which edge 71, in combination with the auxiliary portion 25 on the sheet 21, considerably increases the space on the wall 6 for mounting the opening device, as a result of the outward projection.

In particular, the edge 71 comprises a straight intermediate portion 71a parallel to the portion of the sealing band 15 that extends beyond the wall 6 and two inclined end portions 71b that diverge when they extend towards the sealing band 15 and connect the intermediate portion 71a to the respective side edge 68 of the wall 6.

The portion 17 of the wall 6 comprises two further bending lines 72 extending along opposite sides of the opening device and constituting, together with the intermediate portion 71a of the edge 71 and the sealing band 15, a flat panel 73.

The bend line 72 is straight, extends between the sealing band 15 and two respective opposite ends of the intermediate portion 71a of the edge 71, is inclined with respect to the sealing band 15 and converges towards the edge 71.

The plate 73 is slightly inclined with respect to the horizontal and to the wall 7, and is inclined downwards as it approaches the folded edge 71.

The portion 17 of the wall 6 also comprises two tab portions 74 which are inclined with respect to the flat surface 73 and which connect the latter to the opposite edges 68 of the wall 6.

The portion 18 of the wall 6 comprises a further fold line 75 (schematically shown in dotted lines in fig. 6) so as to incline the portion 18 in the same direction as the plate 73 of the portion 17. In particular, the bending line 75 is substantially U-shaped, with a recess facing the edge 71, made up of two facing L-shaped portions separated by the end portions of the longitudinal sealing band 19 of the wall 6.

The advantages of the package 1, 1' according to the invention are clear from the foregoing description.

In particular, between the sealing band 15 and the bending line 22 of the sheet 21 formed by the band 15, a strip-shaped auxiliary portion 25 of packaging material remains, thus increasing the space available for mounting the opening devices on the wall 6 of the package 1, 1', increasing the area of this auxiliary portion. Thus, the package 1, 1' thus constructed can be fitted with a larger opening device 8, so that the food enclosed by the package, even a semi-fluid food or a food containing fibres and particles, can be easily filled and the package can be easily used by the consumer. For example, direct access to the package is possible.

In addition, when forming both the C-shaped or upturned front edge 71 and the top sheet 21 comprising the secondary portion 25 of packaging material on the same package 1, 1', the space for mounting the opening device 8 on the top wall of the package is considerably increased.

It is clear that various modifications can be made to the packages 1, 1' as described and illustrated above, without departing from the scope of the appended claims.

In particular, the packages 1, 1' may be manufactured by forming a blank of packaging material into a package on a forming device.

Claims (12)

1. A sealed package (1, 1') for pourable food products, made from a web of packaging material, comprising a top wall (6) across which is straddled at least one transverse sealing band (15) forming a flat projecting tab (21) folded along a bending line (22) coplanar with the top wall (6) and onto the top wall (6), and opening means (8) fitted on a portion of said top wall (6) bounded on one side by said sealing band (15); characterized in that said tab (21) comprises a flat strip-shaped auxiliary portion (25) located between said sealing band (15) and said bending line (22), the width of said auxiliary portion (25) being such as to increase the area of the portion of said top wall (6) available for said opening device (8).

2. A package as claimed in claim 1, wherein said sealing band (15) divides said top wall (6) into a first portion (17) defining the portion housing said opening device (8) and a second portion (18) having an area smaller than the area of the first portion (17).

3. A package as claimed in claim 2, characterized in that said sheet (21) and said sealing band (15) extend beyond said top wall (6) at two opposite side walls (4, 5) of the package (1, 1') and define, with said top wall (6) and said side walls (4, 5), respective flat triangular side portions (20) of the packaging material, which side portions (20) are folded coplanar with said side walls (4, 5) and are folded from said top wall (6) onto the respective said side walls (4, 5); the bend line (22) is formed at the bottom of the sheet (21), the bend line (22) comprising a main portion (22a) formed along the top wall (6) on one side of the second portion (18) and opposite end portions (22b) formed on both sides of the respective side portions (20).

4. A package according to any of the preceding claims, wherein the package is parallelepiped-shaped.

5. A package as claimed in claim 1, wherein said top wall (6) comprises a convex C-shaped front edge (71) projecting outwards and defining, on opposite sides of said sealing band (15), a portion of the top wall (6) available for housing said opening device (8).

6. A package as claimed in claim 5, characterized in that said front edge (71) comprises a straight middle portion (71a) parallel to said sealing band (15) and two inclined end portions (71b) diverging towards the sealing band (15) and joining said middle portion (71a) to the respective side edges (68) of said top wall (6).

7. A package as claimed in claim 5, wherein the first portion (17) of said wall (6) is inclined with respect to the horizontal and is inclined downwards towards said first edge (71), at least at the portion intended to house said opening device (8); and the second portion (18) of the top wall (6) comprises at least one further bending line (75) so that the second portion (18) is inclined in the same direction of inclination as the first portion (17).

8. A package according to claim 1, characterized in that it further comprises a flat rectangular bottom wall (7); and the front wall (2), the rear wall (3) and the side walls (4, 5) are interconnected by an inclined intermediate portion (70).

9. A package as claimed in claim 8, characterized in that said inclined intermediate portion (70) tapers towards said top and bottom walls (6, 7) and converges at the respective vertices of said top and bottom walls (6, 7).

10. A method of manufacturing a sealed package (1, 1') for a pourable food product from a packaging material, said method comprising the steps of:

forming a box-shaped member (60) which is open at the top and filled with the food;

-forming a top wall (6) for closing said box-shaped element (60), across which is spanned at least one transverse sealing band (15) forming a flat projecting tab (21) which delimits, on one side, a portion of the top wall (6) which can be used to house an opening device (8);

-folding said sheet (21) so as to be coplanar with said top wall (6) and so as to be folded on said top wall (6) along a bending line (22) previously formed on said packaging material;

characterized in that the above-mentioned steps of forming the above-mentioned top wall (6) are: -sealing the top of said box-shaped element (60) at a predetermined distance (Z) from said bending line (22) on said packaging material, so that, when folded, said sheet (21) comprises, between the bending line (22) and said sealing band (15), a flat strip-shaped auxiliary portion (25) having a width that increases the area of the portion of said top wall (6) available for housing said opening device (8).

11. A method as claimed in claim 10, wherein said steps of forming said box-shaped element (60) and forming said top wall of said box-shaped element (60) are: the tube (31) of packaging material, which is conveyed along a vertical path (P), is transversally sealed in an equally spaced manner and continuously injected from the top with the aforementioned food product.

12. A method as claimed in claim 11, wherein said tube (31) of packaging material is formed by longitudinally folding and sealing a continuous web (32) of packaging material.