Patent Description:
The present invention also relates to a sheet packaging material for producing a sealed package containing a pourable food product.

As commonly known, many pourable food products, such as fruit juice, UHT (ultra-high-temperature treated) milk, wine, tomato sauce, etc., are sold in packages made of sterilized packaging material.

A typical example is the parallelepiped-shaped package for liquid or pourable food products known as Tetra Brik Aseptic (registered trademark), which is made by folding, sealing and cutting a web of laminated packaging material. In particular, the packaging material has a multilayer structure comprising a base layer, e.g. of paper, covered on both sides with layers of heat-seal plastic material, e.g. polyethylene. In the case of aseptic packages for long-storage products, such as UHT milk, the packaging material also comprises a layer of oxygen-barrier material, e.g. an aluminium foil, which is superimposed on a layer of heat-seal plastic material, and is in turn covered with another layer of heat-seal plastic material forming the inner face of the package eventually contacting the food product.

Packages of this sort are normally produced on fully automatic packaging machines, on which a continuous tube is formed from the web-fed packaging material; the web of packaging material is sterilized on the packaging machine, e.g. by applying a chemical sterilizing agent, such as a hydrogen peroxide solution, which, once sterilization is completed, is removed from the surfaces of the packaging material, e.g. evaporated by heating; the web so sterilized is then maintained in a closed, sterile environment, and is folded and sealed longitudinally to form a tube, which is fed vertically.

In order to complete the forming operations, the tube is filled with the sterilized or sterile-processed food product, and is sealed and subsequently cut along equally spaced cross sections; pillow packs are so obtained, which are then folded mechanically to form respective finished packages at a final folder.

To allow folding of the web packaging material both during forming and final folding, crease lines, i.e. weakening lines, are formed on the packaging material at the production plant by creasing tools. In practice, the crease lines define folding lines along which the pillow packs are folded to take the desired final configuration.

Alternatively, the packaging material may be cut into blanks, which are formed into packages on forming spindles, and the resulting packages are then filled with the food product and sealed. One example of this type of package is the so-called "gable-top" package known by the trade name Tetra Rex (registered trademark).

To open the above-described packages, these are normally provided with a removable portion, which is partly detached by an opening device from the rest of the packaging material to free a pour opening through which to pour out the product.

The removable portion is formed on the packaging material prior to folding and sealing the packaging material to form the finished package.

The removable portion normally comprises a so-called "prelaminated" hole, i.e. a circular hole formed through the base layer only of the packaging material and covered, when the material is laminated, with the layers of heat-seal plastic material and barrier material, which adhere to one another at the hole.

Each package of the above type, either cut from a tube of packaging material or formed on a forming spindle, is obtained from a basic unit of packaging material having given crease lines.

In other words, the above-mentioned basic unit represents the exact length of the packaging material used to produce one single package.

In the case of packages made from a tube of packaging material, the original web includes a plurality of basic units joined to each other; in the case of packages made on forming spindles, the basic unit is defined by the blank cut from the web prior to starting the forming and sealing operations.

The basic unit typically has a rectangular or square configuration with two boundary edges parallel to a longitudinal direction and two other boundary edges parallel to a transversal direction orthogonal to the longitudinal direction.

Once the basic unit is folded and sealed to form the respective finished package, the longitudinal direction becomes the direction along which the total height of the package itself is defined; the longitudinal direction also represents the main direction of extension of the web from which the basic unit is obtained.

The basic unit usually includes at least two transversal crease lines extending transversally to the longitudinal direction and dividing the basic unit itself into:.

The transversal crease lines are also configured to define a bottom peripheral outline and a top peripheral outline of the finished package having endless configurations and respectively dividing the bottom portion and the top portion from the main portion.

The bottom portion of the finished package normally includes a flat and horizontal bottom panel defining the resting surface of the package itself.

The top portion of the finished package may include a flat and horizontal top panel, parallel to the bottom panel; alternatively, slanted top panels are very conveniently used in combination with opening devices because they are wider than corresponding flat top panels of parallelepiped or prismatic packages and therefore allow the application of larger opening devices, e.g. provided with screw caps or the like.

As it is known, after their production, packages are transported to sale points by placing them on transport pallets, which have pre-determined sizes. A need is therefore particularly felt in the packaging field to optimize filling of the transport pallets with the finished packages while maintaining a pleasing appearance of such packages.

<CIT> addresses the problem of providing a packaging container with a novel triangular cross section and a production method for said container. The packaging container obtained by: tube-form molding by vertical sealing of a web-shaped packaging material; filling inside the tube-shaped packaging material; horizontal sealing in the transverse direction of the tube-shaped packaging material; forming of a pillow-shaped container body; cutting off of individual pillow-shaped container bodies; and forming into a final shape by folding along creases to form a top wall, a side wall, and a bottom wall and attaching formed fins and flaps to said walls. The top wall and bottom wall have a triangular and a rectangular shape, respectively; the cross-section in the transverse direction of a packaging container main body, formed by four ridgelines that connect the triangulation points of the top wall and the four corner points of the bottom wall, is trapezoidal, and one corner point of the horizontal top wall protrudes towards the front side wall.

<CIT> discloses a spout element for packaging, in particular composite packaging for liquid foodstuffs, said packaging having a polyhedral gable-shaped region and folded packaging casing flaps and the spout element having a main body, a polyhedral flange which is provided for connecting to a packaging casing and the connecting surfaces of which converge at surface meeting points; composite packaging for liquid foodstuffs, having a polyhedral gable-shaped region and folded packaging casing flaps, in which packaging the packaging casing is connected to the spout in a corresponding manner; and composite packaging for liquid foodstuffs having such a spout element. In order to keep the packaging undamaged and thus leak-tight during the connecting process between the spout element and packaging casing and during the folding of the packaging casing flaps, provision is made for receiving regions for the folding line of the packaging casing flaps to be formed in the region of the surface meeting points.

<CIT> discloses a sealed package for pourable food products, comprising a quadrangular bottom panel which comprises a first front edge and a second rear edge opposite to each other; a quadrangular top panel which is opposite to bottom panel and comprises a third front edge and a fourth rear edge; a front panel which extends between first and third edges; and a rear panel which extends between second and fourth edges; the distance between first and third edges is smaller than the distance between second and fourth edges; top panel is angled with respect to a first plane defined by first and second edges; first and third edge define a second theoretical reference plane; front panel comprises a fifth and sixth edge which are opposite to one another and extend both between first and second edges; at least one of fifth and sixth front edge extends at least partially on the opposite side of a second theoretical plane with respect to rear panel; front panel comprises at least a first region which extends on the opposite side of a second theoretical plane with respect to rear panel.

It is therefore an object of the present invention to provide a sealed package containing a pourable food produce, which allows meeting the above-mentioned need in a straightforward and low-cost manner.

This object is achieved by a sealed package as claimed in claim <NUM>.

This object is also achieved by a sheet packaging material for producing a sealed package containing a pourable food product, as claimed in claim <NUM>.

Two preferred, non-limiting embodiments of the present invention will be described by way of example with reference to <FIG> and two examples not falling within the scope of the claims will be described by way of example with reference to <FIG>, in which:.

Number <NUM> in <FIG> indicates as a whole a sealed package according to the present invention, which contains a pourable food product and is obtained from a sheet packaging material <NUM> as shown in <FIG>.

Package <NUM> comprises a bottom portion <NUM>, a top portion <NUM> and a main portion <NUM> interposed between bottom portion <NUM> and top portion <NUM> and including a plurality of side wall portions <NUM>, each one delimited by two opposite lateral edge zones <NUM>.

Main portion <NUM> is divided from bottom portion <NUM> by a bottom peripheral outline <NUM> having an endless configuration defined by a broken line. In a completely analogous manner, main portion <NUM> is divided from top portion <NUM> by a top peripheral outline <NUM>, also having an endless configuration defined by a broken line.

Bottom portion <NUM> includes a flat and horizontal bottom panel <NUM> having a quadrilateral, i.e. rectangular or square (in the example shown rectangular), profile and defining the resting surface of the package itself.

Bottom panel <NUM> is delimited by bottom peripheral outline <NUM> in turn formed by four segments or contour edges, i.e. a bottom front edge 8a, a bottom rear edge 8b parallel to bottom front edge 8a and two bottom side edges 8c, orthogonal to bottom front edge 8a and bottom rear edge 8b.

Due to the rectangular profile of bottom panel <NUM>, bottom front edge 8a and bottom rear edge 8b have the same length; the same applies to bottom side edges 8c, which also have the same length.

Package <NUM> extends vertically along a longitudinal direction A, which is orthogonal to bottom panel <NUM> and along which the total height of the package <NUM> itself is defined. Longitudinal direction A is also orthogonal to bottom front edge 8a, bottom rear edge 8b and bottom side edges 8c of bottom peripheral outline <NUM>.

It is pointed out that, in the present description and in the claims, the term "total height" means either the height of the package when the latter has a constant height or the maximum height of the package when the latter has a variable height.

Bottom portion <NUM> further includes two bottom lateral flaps <NUM> having substantially triangular configurations and folded in a known manner onto bottom panel <NUM> (<FIG>).

Top portion <NUM> includes a flat and slanted top panel <NUM> having a quadrilateral, i.e. a square or a rectangular, profile and having a sloping configuration forwards with respect to longitudinal direction A.

In the example shown in <FIG>, top panel <NUM> is a rectangle approximating a square.

Top panel <NUM> is delimited by top peripheral outline <NUM> in turn formed by four segments or contour edges, i.e. a top front edge 9a parallel to bottom front edge 8a and bottom rear edge 8b, a top rear edge 9b, parallel to top front edge 9a and arranged higher than the top front edge 9a itself, and two top side edges 9c, orthogonal to top front edge 9a and top rear edge 9b and inclined with respect to longitudinal direction A.

As a consequence, top peripheral outline <NUM> extends transversally with respect to longitudinal direction A.

Due to the rectangular profile of top panel <NUM>, top front edge 9a and top rear edge 9b have the same length; the same applies to top side edges 9c, which also have the same length.

Top portion <NUM> further includes two top lateral flaps <NUM> having substantially triangular configurations and folded in a known manner onto two opposite side wall portions <NUM> of main portion <NUM>.

As visible in <FIG> and <FIG>, top portion <NUM> is also provided with an opening device <NUM> of plastic material placed over and around a removable portion <NUM> (<FIG>) of the packaging material <NUM>. Opening device <NUM> is applied onto top panel <NUM> by conventional fastening systems, such as adhesives, or by micro-flame, electric-current-induction, ultrasound, laser, injection moulding or other heat-sealing techniques.

In the example shown in <FIG>, main portion <NUM> of package <NUM> includes four side wall portions <NUM> with different profiles and sizes; advantageously, lateral edge zones <NUM> delimiting side wall portions <NUM> have rounded configurations.

In particular, a first side wall portion <NUM>, designed to define a front face of package <NUM>, has a substantially rectangular configuration delimited, at bottom and top, by straight bottom front edge 8a and top front edge 9a, and at opposite sides, by respective rounded and convex lateral edge zones <NUM>.

A second side wall portion <NUM>, designed to define a rear face of package <NUM>, also has a substantially rectangular configuration and is delimited, at bottom and top, by straight bottom rear edge 8b and top rear edge 9b, and at opposite sides, by respective rounded and convex lateral edge zones <NUM>; this second side wall portion <NUM> faces the side wall portion <NUM> designed to define the front face of the package <NUM> and has a height, parallel to longitudinal direction A, greater than the height of this latter side wall portion <NUM>.

Each of the other two side wall portions <NUM> has a profile substantially resembling a rectangular trapezium delimited:.

The two side wall portions <NUM> having the trapezoidal profiles receive the respective top lateral flaps <NUM> on their outer surfaces.

According to an important aspect of the present invention, the area of bottom panel <NUM> is different from the area of a top quadrilateral Q (<FIG>) obtained by projecting, along longitudinal direction A, top panel <NUM> on a reference plane P (<FIG>) parallel to the bottom panel <NUM>, crossing package <NUM> and containing top front edge 9a of top peripheral outline <NUM>.

In particular, the area of bottom panel <NUM> is smaller than the area of top quadrilateral Q.

According to another possible variant not shown, the area of bottom panel <NUM> may be bigger than the area of top quadrilateral Q.

Analogously to top panel <NUM>, top quadrilateral Q is a square or a rectangle, in the examples shown a rectangle approximating a square.

With particular reference to <FIG>, top quadrilateral Q includes a top front segment Q1, corresponding to bottom front edge 8a, a top rear segment Q2, corresponding to bottom rear edge 8b, and two top side segments Q3, respectively corresponding to bottom side edges 8c.

Preferably, top side segments Q3 have the same length, which is in turn different from the length of bottom side edges 8c. More specifically, in the example shown, the length of bottom side edges 8c is smaller than the length of top side segments Q3.

In a similar way, top front segment Q1 and top rear segment Q2 have the same length, which is in turn different from the length of bottom front edge 8a and bottom rear edge 8b.

More specifically, in the example shown, the length of bottom front edge 8a and bottom rear edge 8b is greater than the length of top front segment Q1 and top rear segment Q2.

The packaging material <NUM> from which package <NUM> is made is shown in <FIG> and has a known multilayer structure (not shown) comprising a base layer, e.g. of paper, for stiffness, and a number of lamination layers covering both sides of the base layer.

Preferably, the lamination layers comprise one layer of oxygen-barrier material, e.g. an aluminum foil, and a number of layers of heat-seal plastic material covering both sides of the base layer and both sides of the layer of oxygen-barrier material. In other words, by proceeding from the side eventually forming the inside of package <NUM>, packaging material <NUM> comprises one layer of heat-seal plastic material, one layer of oxygen-barrier material, another layer of heat-seal plastic material, the base layer, and one or more additional layers of heat-seal plastic material.

The letter M in <FIG> indicates a basic unit of packaging material <NUM>, by which to produce package <NUM>, and which may be a precut blank, or a portion of a web of packaging material comprising a succession of basic units M.

In the first case, basic unit M is folded on a known forming spindle (not shown), is filled with the food product, and is sealed at the top to form the final package.

In the second case, described therein with reference to <FIG>, the web of packaging material <NUM>, comprising a succession of basic units M, is:.

After completion of these operations, package <NUM> has:.

More specifically, after package <NUM> is completely sealed and formed, bottom panel <NUM> is crossed by bottom transverse sealing band <NUM> and by an end portion 20a of longitudinal sealing band <NUM> extending perpendicularly from the bottom transverse sealing band <NUM>.

In a completely analogous way, after package <NUM> is completely sealed and formed, top panel <NUM> is crossed by top transverse sealing band <NUM> and by an end portion 20b of longitudinal sealing band <NUM> extending perpendicularly from the top transverse sealing band <NUM> and opposite to end portion 20a; in greater detail, top transverse sealing band <NUM> divides top panel <NUM> into two zones 14a, 14b and end portion 20b of longitudinal sealing band <NUM> extends on one (14b) of such zones 14a, 14b from an intermediate portion of the top transverse sealing band <NUM>.

During the forming operations to obtain package <NUM>, top transverse sealing band <NUM> is folded on zone 14b and end portion 20b of longitudinal sealing band <NUM>; in this way, zone 14a has a bigger area than zone 14b and is therefore more suitable for receiving removable portion <NUM> and opening device <NUM>.

In the example shown in <FIG>, removable portion <NUM> has a circular profile and is designed to be at least partly detached in use from the rest of the packaging material by opening device <NUM> to free a pour opening through which to pour out the product.

Removable portion <NUM> is formed on packaging material <NUM> prior to folding and sealing the packaging material <NUM> itself to form the finished package.

In the present case, removable portion <NUM> comprises a so-called "prelaminated" hole, i.e. a circular hole formed through the base layer only of packaging material <NUM> and covered, when the packaging material <NUM> itself is laminated, with the layers of heat-seal plastic material and oxygen-barrier material, which adhere to one another at the hole.

With particular reference to <FIG>, basic unit M of packaging material <NUM> has a rectangular configuration and is delimited by:.

Basic unit M of packaging material <NUM> comprises a number of crease lines defining respective fold lines, along which the packaging material <NUM> itself is folded to form the finished package <NUM>.

More specifically, basic unit M comprises two transversal crease lines <NUM>, <NUM> extending transversally with respect to longitudinal direction A and dividing the basic unit M itself into:.

Transversal crease line <NUM> extends parallel to bottom boundary edge <NUM> and top boundary edge <NUM> and is arranged closer to bottom boundary edge <NUM> than transversal crease line <NUM>. Transversal crease line <NUM> is configured to define bottom peripheral outline <NUM> of package <NUM>.

In particular, transversal crease line <NUM> includes:.

Transversal crease line <NUM> is arranged closer to top boundary edge <NUM> than transversal crease line <NUM> and is configured to define top peripheral outline <NUM> of package <NUM>. In particular, transversal crease line <NUM> has a broken-line shape with:.

As visible in <FIG>, top side portions 26c converge towards top central portion 26a.

Basic unit M includes two further transversal crease lines <NUM>, <NUM> extending parallel to direction B and placed near bottom boundary edge <NUM> and top boundary edge <NUM>, respectively; transversal crease lines <NUM>, <NUM> delimit with bottom boundary edge <NUM> and top boundary edge <NUM> respective bottom transversal sealing area <NUM> and top transversal sealing area <NUM> configured to define bottom transversal sealing band <NUM> and top transversal sealing band <NUM> of package <NUM>.

Bottom crease pattern <NUM> is designed to produce bottom panel <NUM> and bottom lateral flaps <NUM> of package <NUM>. In particular, bottom crease pattern <NUM> includes, in a known manner, four longitudinal crease lines 36a, 36b parallel to longitudinal direction A and extending between transversal crease lines <NUM> and <NUM>.

Longitudinal crease lines 36b are the most internal ones, whilst longitudinal crease lines 36a are located near opposite side boundary edges <NUM>; the area between longitudinal crease lines 36b as well as the areas delimited by longitudinal crease lines 36a with the respective side boundary edges <NUM> are configured to define bottom panel <NUM> of package <NUM>.

In each of the areas delimited between longitudinal crease lines 36a and 36b, bottom crease pattern <NUM> further includes two additional crease lines <NUM>, <NUM> inclined with respect to both longitudinal direction A and transversal direction B.

In particular, the additional crease lines <NUM>, <NUM> of each pair have one end in common located on transversal crease line <NUM> and opposite ends located at the intersection points between transversal crease line <NUM> and longitudinal crease lines 36a and 36b, respectively. In this way, each pair of additional crease lines <NUM>, <NUM> delimits a triangle <NUM> with the segment of transversal crease line <NUM> comprised between the additional crease lines <NUM>, <NUM> themselves.

Each area between longitudinal crease lines 36a and 36b is configured to define one respective bottom lateral flap <NUM> of package <NUM>.

Top crease pattern <NUM> is designed to produce top panel <NUM> and top lateral flaps <NUM> of package <NUM>. In particular, top crease pattern <NUM> includes four longitudinal crease lines 40a, 40b parallel to longitudinal direction A and extending between transversal crease lines <NUM> and <NUM>.

Longitudinal crease lines 40b are the most internal ones, whilst longitudinal crease lines 40a are located near opposite side boundary edges <NUM>; the area between longitudinal crease lines 40b as well as the areas delimited by longitudinal crease lines 40a with the respective side boundary edges <NUM> are configured to define top panel <NUM> of package <NUM>. Removable portion <NUM> is formed in the area of top region <NUM> comprised between longitudinal crease lines 40b.

In each of the areas delimited between longitudinal crease lines 40a and 40b, top crease pattern <NUM> further includes two additional crease lines <NUM>, <NUM> inclined with respect to both longitudinal direction A and transversal direction B.

In particular, the additional crease lines <NUM>, <NUM> of each pair have one end in common located on transversal crease line <NUM> and opposite ends located at, or adjacent to, the opposite ends of the respective inclined top side portion 26c of transversal crease line <NUM>.

In this way, each pair of additional crease lines <NUM>, <NUM> delimits a triangle <NUM> with the respective top side portion 26c of transversal creased line <NUM>.

Each area between longitudinal crease lines 40a and 40b is configured to define one respective top lateral flap <NUM> of package <NUM>.

According to an important aspect of the present invention, the length of top central portion 26a of transversal crease line <NUM> is different from the length of bottom central portion 25a of transversal crease line <NUM>; in addition, the length of each of bottom side portions 25c of transversal crease line <NUM> is also different from the length of the projection R, parallel to longitudinal direction A, of each of top side portions 26c of transversal crease line <NUM> on a reference line S parallel to transversal crease line <NUM> and containing top central portion 26a.

In particular, the length of top central portion 26a is smaller than the length of bottom central portion 25a; in a different manner, the length of each projection R is greater than the length of the corresponding bottom side portion 25c.

As visible in <FIG>, the length of bottom central portion 25a corresponds to the length of the segment of transversal crease line <NUM> comprised between longitudinal crease lines 36b; in a completely analogous manner, the length of top central portion 26a corresponds to the length of the segment of transversal crease line <NUM> comprised between longitudinal crease lines 40b.

The same applies to bottom side portions 25c, whose lengths correspond to the lengths of the respective segments of transversal crease line <NUM> comprised between each pair of longitudinal crease lines 36a and 36b. Analogously, the lengths of projections R correspond to the lengths of the respective segments of transversal crease line <NUM> comprised between each pair of longitudinal crease lines 40a and 40b.

It is important to note that the length of top front segment Q1 and top rear segment Q2 of top quadrilateral Q corresponds to the length of top central portion 26a; in an analogous manner, the length of top side segments Q3 of top quadrilateral Q corresponds to the length of projections R.

In the embodiment shown in <FIG>, intermediate region <NUM> includes a central transversal band <NUM> having a uniform structure, i.e. lacking any creasing or weakening, and crossing the areas of the intermediate region <NUM> itself designed to form the respective lateral edge zones <NUM> of side wall portions <NUM> of package <NUM>.

Preferably, intermediate region <NUM> of basic unit M further comprises a plurality of V-shaped crease lines <NUM> having respective vertices <NUM> located on or adjacent to the transversal crease lines <NUM>, <NUM> and at given points thereof designed to define the opposite ends of respective lateral edge zones <NUM> delimiting the side wall portions <NUM> of package <NUM>; each V-shaped crease line <NUM> extends from and in proximity of the respective transversal crease line <NUM>, <NUM> up to central transversal band <NUM> and comprises two legs <NUM> diverging from the respective vertex <NUM>.

In particular, each V-shaped crease line <NUM> extends from the respective transversal crease line <NUM>, <NUM> towards the other transversal crease line <NUM>, <NUM> and has a size, parallel to longitudinal direction A, greater than zero and smaller than one fourth, preferably smaller than one tenth, of the total height of intermediate region <NUM> measured parallel to the longitudinal direction A itself.

It is pointed out that, in the present description and in the claims, the term "total height of intermediate region <NUM>" corresponds to the total height of the package.

In practice, each V-shaped crease line <NUM> extending from transversal crease line <NUM> and the corresponding V-shaped crease line <NUM> extending from transversal crease line <NUM> are spaced apart parallel to longitudinal direction A.

Preferably, each V-shaped crease line <NUM> has a size, parallel to longitudinal direction A, smaller than the maximum height of bottom region <NUM> or top region <NUM> measured parallel to the longitudinal direction A itself.

More preferably, each leg of the V-shaped crease lines <NUM> has a length smaller than the maximum length of the heights of triangles <NUM>, <NUM> with reference to their bases on respective transversal crease lines <NUM>, <NUM>.

In the example shown, each V-shaped crease line <NUM> has a size, parallel to longitudinal direction A, substantially equal to one fourteenth of the total height of intermediate region <NUM> measured parallel to the longitudinal direction A itself.

As visible in <FIG>, V-shaped crease lines <NUM> are the only crease lines present in intermediate region <NUM> at the areas designed to define lateral edge zones <NUM> between side wall portions <NUM> of package <NUM>.

Due to the absence of continuous longitudinal crease lines between transversal crease lines <NUM>, <NUM>, the resulting package <NUM> presents a round configuration along lateral edge zones <NUM>. V-shaped crease lines <NUM> perform the function of easing folding of the packaging material <NUM> at the corners between lateral edge zones <NUM> of side wall portions <NUM> and bottom peripheral outline <NUM> and top peripheral outline <NUM> without affecting the round configuration of lateral edge zones <NUM>.

In the example shown, legs <NUM> of each V-shaped crease line <NUM> are rectilinear or straight; as a possible alternative not shown, legs <NUM> of each V-shaped crease line <NUM> may also be curved, preferably with their concavities facing one another.

Preferably, legs <NUM> of each V-shaped crease line <NUM> delimit an angle comprised between <NUM>° and <NUM>°.

Number <NUM>' in <FIG> indicates as a whole a different embodiment of a sealed package according to the present invention and obtained by a basic unit M' (<FIG>) of sheet packaging material <NUM>. Package <NUM>' being similar to package <NUM>, the following description is limited to the differences between them, and using the same references, where possible, for identical or corresponding parts; the same applies for basic units M' and M.

In particular, package <NUM>' differs from package <NUM> only in that lateral edge zones <NUM> between side wall portions <NUM> are defined by respective longitudinal crease lines <NUM> extending between transversal crease lines <NUM> and <NUM>. Longitudinal crease lines <NUM> are slightly slanted with respect to longitudinal direction A due to the different lengths between bottom central portion 25a and top central portions 26a of transversal crease lines <NUM>, <NUM> as well as between bottom side portions 25c of transversal crease line <NUM> and respective projections R on reference line S.

In this case, there is no need for V-shaped crease lines, which are therefore absent.

Number <NUM>" in <FIG> indicates an example of a sealed package, not falling within the scope of the claims, obtained by a basic unit M" (<FIG>) of sheet packaging material <NUM>. Package <NUM>" being similar to package <NUM>, the following description is limited to the differences between them, and using the same references, where possible, for identical or corresponding parts; the same applies for basic units M" and M.

In particular, package <NUM>" differs from package <NUM> only by having a top panel <NUM>" that extends horizontally and parallel to bottom panel <NUM>.

In greater details, top panel <NUM>" is delimited by a top peripheral outline <NUM>" (formed by edges 9a", 9b", 9c") parallel to bottom peripheral outline <NUM> and deriving by a transversal crease line <NUM>'' also parallel to transversal crease line <NUM> and to transversal direction B.

In this case, top panel <NUM>'' extends entirely on reference plane P and therefore the projection of top panel <NUM>" on this latter plane, i.e. top quadrilateral Q, coincides with the top panel <NUM>" itself.

The same applies to the projections R of top side portions 26c" of transversal crease line <NUM>'' on reference line S, which coincide with the top side portions 26c" themselves; in fact, in this case, reference line S coincides with top transversal crease line <NUM>".

Number <NUM>‴ in <FIG> indicates an example of a sealed package, not falling within the scope of the claims, obtained by a basic unit M‴ (<FIG>) of sheet packaging material <NUM>. Package <NUM>‴ being similar to package <NUM>", the following description is limited to the differences between them, and using the same references, where possible, for identical or corresponding parts; the same applies for basic units M‴ and M".

In particular, package <NUM>‴ differs from package <NUM>" only in that lateral edge zones <NUM> between side wall portions <NUM> are defined by respective longitudinal crease lines <NUM> extending between transversal crease lines <NUM> and <NUM>. Even in this case, longitudinal crease lines <NUM> are slightly slanted with respect to longitudinal direction A due to the different lengths between bottom central portion 25a and top central portion 26a'' of transversal crease lines <NUM>, <NUM>" as well as between bottom side portions 25c and top side portion 26c" of the same transversal crease lines <NUM>, <NUM>".

Thanks to the presence of longitudinal crease lines <NUM>, there is no need for V-shaped crease lines, which are therefore absent.

The advantages of packages <NUM>, <NUM>' and basic units M, M' of packaging material <NUM> according to the present invention will be clear from the above description.

In particular, all the solutions of packages <NUM>, <NUM>' described present bottom portions <NUM> slightly different from the top portions <NUM>. In this way, it is possible to optimize filling of the transport pallets with the finished packages <NUM>, <NUM>', which present high flexibility in their dimensions without imparting relevant changes in their appearance. For instance, a slimmer bottom portion <NUM> than the top portion <NUM> permits to compensate the bulging effect produced by gravity on the pourable product contained in the package when placed in the upright position, which product tends to accumulate in the bottom portion of the package <NUM>, <NUM>' itself.

Claim 1:
A sealed package (<NUM>, <NUM>') containing a pourable food product and comprising a bottom portion (<NUM>), a top portion (<NUM>) and a main portion (<NUM>) interposed between said bottom portion (<NUM>) and said top portion (<NUM>) and including a plurality of side wall portions (<NUM>);
wherein said main portion (<NUM>) is divided from said bottom portion (<NUM>) and said top portion (<NUM>) respectively by a bottom peripheral outline (<NUM>) and a top peripheral outline (<NUM>), each having an endless configuration and extending transversally with respect to a longitudinal direction (A), along which the total height of the package (<NUM>, <NUM>') is defined;
wherein each of said bottom peripheral outline (<NUM>) and said top peripheral outline (<NUM>) has a broken-line shape and is formed by a plurality of contour edges (8a, 8b, 8c; 9a, 9b, 9c) joined to each other;
wherein said bottom portion (<NUM>) comprises a quadrilateral bottom panel (<NUM>) delimited by said bottom peripheral outline (<NUM>) and extending orthogonal to said longitudinal direction (A); and
wherein said top portion (<NUM>) comprises a quadrilateral top panel (<NUM>) delimited by said top peripheral outline (<NUM>) and extending transversally to said longitudinal direction (A);
wherein said top panel (<NUM>) is slanted with respect to said bottom panel (<NUM>), said reference plane (P) and said longitudinal direction (A);
characterized in that the area of the bottom panel (<NUM>) is different from the area of a top quadrilateral (Q) obtained by projecting, along said longitudinal direction (A), said top panel (<NUM>) on a reference plane (P) parallel to said bottom panel (<NUM>), crossing the package (<NUM>, <NUM>') and containing at least one (9a) of the contour edges (9a, 9b, 9c) of said top peripheral outline (<NUM>).