MXPA06011401A - Gable-top package for pourable food products and method for dimensioning thereof - Google Patents

Abstract

A gable top package (1, 1') for pourable food products produced by folding and sealing a sheet packaging material (2) and provided with a gabled top portion (4) including front and back sloping top wall (10, 11) joined together at a top transversal seal (12), and a pair of side top walls (18, 19) connecting respective lateral edges (15, 16) of said front and back sloping top walls (10, 11) and obtained by folding respective portions (46, 47) of the sheet packaging material (2) along predetermined crease lines (31, 33, 42, 44, 50, 51, 54, 55, 56, 65;31, 33, 43, 45, 52, 53, 57, 58, 59, 66) delimiting a number of panels (A, B, C, D, E, F, G);the above mentioned crease lines (31, 33, 42, 44, 50, 51, 54, 55, 56, 65;31, 33, 43, 45, 52, 53, 57, 58, 59, 66) are determined among a plurality of possible crease lines designed so as the forming of the side top walls (18, 19) is performed by means of rotations of the panels (A, B, C, D, E, F, G) as rigid bodies about their respective crease lines (31, 33, 42, 44, 50, 51, 54, 55, 56, 65;31, 33, 43, 45, 52, 53, 57, 58, 59, 66).

Description

PACKAGING OF TRIANGULAR PIPE FOR FLUID FOOD PRODUCTS AND METHOD FOR THE SIZING OF THE SAME FIELD OF THE INVENTION The present invention is concerned with a triangular top pack for food products that can flow. BACKGROUND OF THE INVENTION As is known, many fluid food products, such as fruit juice, UHT milk (processed at ultra-high temperature), wine, tomato sauce, etc., are sold in packages made of sterilized packaging material. . The packaging material has a multilayer structure comprising a layer of fibrous material, for example paper, covered on both sides with layers of heat sealing plastic material, for example polyethylene; In the case of aseptic packaging for long-term storage products, such as UHT milk, the packaging material also comprises a layer of oxygen barrier material, defined for example by an aluminum film, which is superimposed on a layer of plastic heat sealing material and is in turn covered with another layer of heat sealing plastic material that eventually defines the inner side of the packaging that is put in contact with the product Ref .: 175039 food. Representative examples of such packaging are the parallelepiped packing for liquid or flowable food products known as aseptic packaging Tetra Brik (registered trademark) and the so-called "triangular finishing" packaging commonly known by the trade name Tetra Rex (trademark). registered commercial), which has a triangular top portion defined by two sloping walls or slopes joined together in a superior transverse seal. The above packages can be formed from a continuous tube obtained by folding and longitudinally sealing a cloth packing material; the fabric of the packaging material is sterilized in the packaging machine itself, for example by the application of a chemical sterilizing agent, such as a hydrogen peroxide solution which after sterilization is removed, for example vaporized by heating the surfaces of the packaging material. The fabric of the packaging material thus sterilized is maintained in a closed sterile environment and is folded and sealed longitudinally to form a vertical tube. The tube is filled with the sterilized or sterile food product processed and sealed and cut into equally spaced cross sections to form pillow packs, which are then mechanically folded to form the finished packages. Two basic types of cloth feeding and forming filling machines are known: a first and more common type is a machine having two pairs of reciprocating movement jaws; This type of machines includes, for example, the machines of the TB / 21, TBA / 19 and TBA / 21 series and Tetra Pak A3 packaging machines, produced by Tetra Pak Carton Ambient AB in LUND (Sweden) Rubén Rausings gata and by Tetra Pak Cardboard Ambient SpA in Modena (Italy), Via Delfini 1. The second type of fabric feeding packing machine is the type of endless chain, where forming and sealing units are carried by two front end chains rather then by means of reciprocating jaws . An example of this kind of machine is the TBA / 22 packaging machine, also produced by Tetra Pak Carton Ambient S.p.A. To allow the folding of the fabric packing material during both the forming fold and the final folding, crease lines defining a so-called "crease pattern" are formed on the packaging material in the production line. Alternatively, the packaging material can be cut into preforms, which are formed into packages on the forming mandrel and the resulting packages are filled with the food product and sealed. In particular, once formed on the forming mandrels, the unfinished packages have an open parallelepiped shape upwards; the triangular finishing portion is obtained by compressing opposite side walls in the upper portion of the packages without terminating towards each other in order to stretch the upper edges of the other walls, which are then sealed together to form the transverse seal. Once formed, packages of the above type can undergo additional processing steps, such as the application of a re-sealable opening device. Triangular cap gaskets are very conveniently used in combination with re-sealable opening devices because the upper sloping walls are wider than the corresponding flat portions of the parallelepiped and therefore allow the application of larger opening devices, for example provided with screwed lids or the like. In the packaging industry, there is a need for continuous improvements, particularly as regards the possibility of differentiating shapes and sizes of the triangular finishing packings while ensuring an appropriate folding of the packing material. This need derives from the requirements of the market in terms of variations in the aesthetic appearance of the packages and the need to ensure, for any type of food product, a spill without the phenomenon commonly known as gurgling, that is, the outward flow discontinuous packing product characterized by alternating phases of clogged flow and conspicuous spillage with possible product splashes. As to the last point, it should be noted that different food products may have different viscosities and therefore require different heights of the triangular top portion to ensure proper pouring. BRIEF DESCRIPTION OF THE INVENTION It is an object of the present invention to provide a triangular cap-type package, which allows to satisfy the need mentioned above in a very simple and inexpensive manner. This object is obtained by means of a triangular finishing pack as claimed in claim 1. Another object of the present invention is to devise a method for dimensioning triangular finishing packages of different shapes insofar as an appropriate folding of the packaging material is ensured. This object is obtained by the method according to claim 5. BRIEF DESCRIPTION OF THE DRAWINGS Two preferred non-limiting embodiments of the present invention will be described by way of example with reference to the accompanying figures, in which: Figure 1 is a perspective view of a triangular finishing pack according to the present invention; Figure 2 is a larger scale perspective view of an upper portion of the pouch of Figure 1; Figures 3 and 4 are different perspective views of a pillow pack that constitutes an intermediate product for the production of the package of Figure 1; Figure 5 is a larger scale perspective view of an upper portion of the pillow-pack of Figures 3 and 4 during folding; Figure 6 is a laminar packing material provided with a crease pattern for producing the package of Figure 1; Figure 7 is a larger scale view of a portion of the laminar packaging material of Figure 6; Fig. 8 is a perspective view of another embodiment of a triangular finishing pack according to the present invention. DETAILED DESCRIPTION OF THE INVENTION With reference to Figure 1, the number 1 refers to a triangular finishing package for food products according to the present invention. The package 1 is manufactured from a material of 6) hereinafter in the - ^^. I; r "; it essentially has a present -material aspect - a re . . ^.? e main parallelism shape in the main 3. the 4 mee delimits towards triangular arx * > material 2 defines the length * ^ Particle which is used to produce a "Fa of the packaging material that is ßXaCt multilayer structure of type ^ mie 1 And has a structure only packaging 1 a relative side edge 15 of the front sloping top wall 10 and another side formed by a relative lateral end portion 12a, 12b of the upper transverse seal 12 and folded over a relative side edge 16 of the rear sloping upper wall 11. The side flaps 13, 14 are folded on respective upper portions 20 of the side walls 8, 9; the upper portions 20 are flat and substantially coplanar or moderately inwardly inclined relative to respective side walls 8, 9 as best explained later herein. For a better understanding of the packaging form, reference is now made to Figures 3 to 7. The package 1 can be manufactured from a continuous tube (not shown) of packaging material, which is obed by bending and sealing longitudinally. a cloth packing material, defined by repeated lengths of material 2 (figure 6). More precisely, a portion of the edge 21 of the material 2 is superimposed and sealed on an opposite edge portion 22 to ob a longitudinal seal 23 extending substantially along a vertical center line of the rear wall 7 of the finished package 1. The tube is then sealed transversely at regular intervals to form transverse seals and then cut along such transverse seals to form so-called pillow packs (not shown) which are adapted to be transformed into finished packages 1 by means of a plurality of final folding stages. As is known, a pillow package has a basic portion of parallelepiped and opposite tapered end portions that taper from the basic portion to respective transverse seals. Figures 3, 4 and 5 show an intermediate packet, designated with the number 26 which is obed from a pillow pack by flattening one of the tapered end portions. In particular, the intermediate package 26 comprises a portion 28 of a basic parallelepiped delimited by a base wall and four side walls respectively corresponding to the walls 5, 6, 7, 8, 9 of the main portion 3 of the finished package 1 and a portion of the upper tapered end 29 designed to define the triangular finishing portion 4 of the finished packaging 1 and tapering from the basic portion 28 to the upper transverse seal 12. More specifically, the upper tapered end portion 29 defines front and rear sloping top walls 10, 11 of the finished package 1 and is provided with lateral fins 13, 14 protruding from opposite sides of the front and rear inclined upper walls 10, 11 and as explained above, adapted to be folded on respective upper portions 20 of the walls lateral 8, 9.

Alternatively, the intermediate package 26 can be manufactured from preforms of packaging material, each corresponding to a length of material 2; the preforms' are formed into packages on forming mandrels (not shown) and the resulting packages are filled with the food product and sealed. Material 2 (figure 6) includes a crease pattern , that is, a plurality of weakened lines obed by folding rolls and forming fold lines along which the material is folded during the final forming and folding steps. The fold pattern 30 includes in a known manner four transverse fold lines 31, 32, 33, 34; the lines 31, 32 are close to the transverse ends of the material 2 and delimit respective upper and lower transverse sealing areas 31a, 32a; the lines 33, 34 form the horizontal corners of the triangular finishing portion 4 and of the base wall 5 and are also indicated in figures 1, 3, 4 and 5 for purposes of clarity. The fold pattern 30 also includes in a known manner four longitudinal fold lines 35, 36, 37, 38 which form the side corners of the package 1 and extend between transverse fold lines 33 and 34, also as a plurality of fold lines 40 in the area between line 34 and the bottom transverse sealing area 32a, which are designed to produce lateral bottom fins (known and not shown) of the intermediate package 26, taken to be folded and flattened to obtain the base wall 5.

The lines 40 have a known arrangement and are not described in detail. The longitudinal fold lines 35, 36 are close to respective side edge portions 21, 22, while longitudinal fold lines 37, 38 are interposed between the lines 35 and 36. For purposes of clarity, the front wall 6 of the packaging 1 is delimited by the lines 37 and 38, the rear wall 7 is delimited by the lines 35 and 36, the side wall 8 is delimited by the lines 35 and 37 and the side wall 9 is delimited by the lines 36 and 38. Fold pattern 30 (Figures 5 and 6) further includes a plurality of additional fold lines in the area comprised between the transverse fold lines 31 and 33. Such additional fold lines include four substantially longitudinal fold lines 42, 43, 44 , Defining the lateral corners of the front inclined upper wall 10 and the rear inclined upper wall 11 and originating at the intersection points 35a, 36a, 37a, 38a of the line 33 with each of the longitudinal lines 35, 36, 37, 38. In the examples shown, the lines 42, 43, 44 and 45 are slightly inclined to form trapezoidal walls 10, 11 tapering upwards, but could be perfectly longitudinal, that is, to constitute longitudinal line extensions 35, 36, 37, 38. The lines 42, 44, the portion of the upper transverse sealing area 31 a comprised between the lines 42 and 44 and the portion of line 33 comprised between the points of intersection 35a and 37a delimit a fin area 46 defining the lateral flap 13 and the upper portion 20 of the side wall 8. Similarly, the lines 43, 45, the portion of the lower transverse sealing area 31a comprised between the lines 43 and 45 and the line portion 33 comprised between the points of intersection 36a and 38a delimit a fin area 47 defining the side flap 14 and the upper portion of the side wall 9. In addition, the longitudinal fold lines dinals 42, 43, 44, 45, the transverse fold line 33 and the upper transverse sealing area 31a delimit two other zones 48, 49 each interposed between the areas 46, 47 and respectively defining the upper front and rear sloping walls 10, 11. The fold pattern 37 further includes, in each fin area 46, 47, a pair of inclined fold lines 50, 51 and respectively 52, 53, starting from the points 35a, 37a and respectively 36a, 38a and joined at point 31b and respectively 31c, along fold line 31 to define an isosceles triangle with line portion 33 comprised between points 35a, 37a and respectively 36a, 38a. The lines 50, 51, and respectively the lines 52, 53 define the lateral external limits of the lateral fins 13, 14. Three additional fold lines, indicated with the numbers 54, 55, 56 for the fin areas 46 and respectively with 57, 58, 59 for the fin area 47, extend from the points 35a, 37a, 31b and respectively of the points 36a, 38a, 31c, to an intermediate point located inside the relative isosceles triangle and indicated with the number 60 for the fin area 46, and respectively with 61 for the fin area 47. The fold lines 54, 55 and respectively the fold lines 57, 58 extend symmetrically with respect to a relative extension of the fold line 56 and respectively of the fold line 59. The lines 54, 55 of the fin area 46 extend between the intermediate point 60 and respective points 35a, 37a and delimit upwardly the upper portion 2 of the side wall 8. Similarly, the lines 57, 58 of the fin area 47 extend between the intermediate point 61 and the respective points 36a, 38a and delimit upward the upper portion 20 of the side wall 9. The fold pattern 37 further includes, in each fin area 46, 47, a continuous broken fold line 65, 66, that is, a broken line without interruption, intersecting the relative fold line 50, 52 and extending between the relative midpoint 60 , 61 and the relative intersection point of the transverse fold line 31 with the longitudinal fold line 42, 43. In particular, each continuous broken fold line 65, 66 is divided by the relative fold line 50, 52 in two. portions 67, 68, forming between the same angles close to but different from 180 degrees. The portions 67, 68 extend from the relative fold line 50, 52 to the transverse fold line 31 a and the relative mid point 60, 61, respectively. The fold lines mentioned above in each fin area 46, 47 delimit a number of triangular shaped panels A, B, C, D, E, F, G adapted to be folded according to a predefined sequence described hereinafter . In particular, referring to the fin area 46, the panel A is delimited by the fold lines 31, 44 and 51; the panel B is delimited by the fold lines 51, 55 and 56; the panel C is delimited by the fold lines 33, 54 and 55 and defines the upper portion 20 of the side wall 8; panel D is delimited by fold line 56, portion 68 of fold line 65 and portion of fold line 50 between fold lines 65 and 31; the panel E is delimited by the fold line 54, the portion 68 of the fold line 65 and the portion of the fold line 50 comprised between the fold lines 65 and the point 35a; the panel F is delimited by the fold line 31, the portion 67 of the fold line 65 and the portion of the fold line 50 comprised between the fold lines 65 and the fold line 31 and the panel G is delimited by the crease line 42, the portion 67 of the fold line 65 and the portion of the fold line 50 comprised between the fold lines 65 and the point 35a. The same definition of panels A, B, C, D, E, F, G can be applied to the fin area 47 in a completely analogous manner and will not be repeated since the fin areas 46 and 47 are symmetrical with respect to an axis extending between and parallel to the longitudinal fold lines 37, 38. During the formation of each fin area 46, 47, panels E and B are folded over panel C such that panel F is superimposed on panel G and panel A covers the entire remaining portion of the fin area 46, 47 to define the relative side wall 18, 19. In accordance with an important aspect of the present invention, the fold pattern 30 in each flap region 46, 47 of the material 2 is designed such that the formation of the upper side walls 18, 19 are effected by rotations of the relative panels A, B, C, D, E, F, G as rigid bodies around their respective fold lines (50, 51, 54, 55, 56, 65 for the fin area 46 and 52, 53, 57, 58, 59, 66 for the area of fin 47). It is specified that in the present description and in the claims, the expression "rotation of panels as rigid bodies" does not exclude small deformations of the packaging material due to the thickness thereof, in particular that occurs during the superposition of the panels. More specifically, the crease pattern 30 in each flap region 46, 47 of the material 2 is obtained by: - choosing the value of an upper angle formed, along each lateral upper wall 18, 19 of the package 1, between opposite edges thereof converging to an upper transverse seal 12; - choosing the length 1 of the upper front sloping wall 10, measured in a direction transverse to the upper transverse seal 12; and - determining the position and extension of each fold line 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 65, 66 in each fin area 46, 47 in such a way that the formation of each lateral upper wall 18, 19 is effected by rotations of the relative panels A, B, C, D, E, F, G as rigid bodies around their respective fold lines. Due to the fact that each lateral top wall 18, 19 is defined by the panel A of the relative fin area 46, 47, the angle a is therefore also formed by each fold line 44, 45 with the respective line portion. of fold 31 located inside the respective fin area 46, 47. It has been found that the aforementioned steps allow to define different fold patterns in the fin areas 46, 47, with different shapes consequent to the triangular end portion 4 , by using simple geometric formulas, as explained later in the present. For the sake of simplicity, the part of the description that follows will refer to the fin area 47 only also as to Figures 2 and 7, the same considerations apply equally well to the fin area 46 and are not repeated. In particular, the position and extension of the fold lines 52, 43 can be obtained by determining the angle β formed by such lines 52, 53 with the fold line portion 33 comprised between the points 36a and 38a. The angle ß can be calculated as a function of length 1 by means of the following formula: 1 ß = arctg () c / 2 where c refers to the width of packing 1, which is a given data and corresponds to the distance between fold lines 36 and 38 or 35 and 37. The angle ß allows the construction of crease lines 52, 53 which start from the respective points 36a, 38a and define the equal sides of an isosceles triangle, whose third side is represented by the fold line 33 comprised of the points 36a and 38a. The position and extension of the fold lines 57, 58, 59 and the position of the intermediate point 61 can be obtained by determining the angle β formed by the lines 57, 58 with the respective fold lines 52, 53. The angle ß2 can be calculated by means of the following formula: ß - (? 2 - 0) ß = 2 where? represents the angle formed between each fold line 43, 45 and the respective fold line 52, 53, while? i refers to the angle formed by each fold line 43, 45 with the fold line portion 33 comprised between the points 36a and 38a, after the folding of the triangular finishing portion 4 has been completed and the panel A is superimposed on the panel C. More specifically, the angles? and? i can be calculated as follows:? = 180 ° - - ß, taking into account that a is also the angle formed by each fold line 43, 45 with the respective fold line portion 33 located outside the fin area 47 and departing from the respective points 36a, 38a; c / 2? 2 = arceos () li where l? represents the length of fold lines 43, 45 that can be calculated as a function of length 1 and the upper angle a by the following formula: 1 li = cos (90 - oc) The formula for calculating? i is derived from the Consideration that, after the folding of the triangular end portion 4, the fold line 45 defines the hypotenuse of a triangle of right angles, whose legs are identified by a segment extending from the top vertex of the lateral top wall. at a midpoint of the fold line portion 33 comprised between the points 36a and 38a and in the middle of such a fold line portion 33 adjacent to the hypotenuse. The angle ß2 allows the construction of fold lines 57, 58, 59 and the definition of its intersection point 61. The knowledge of the angles ß2,?,? I, allows calculating the angle ßi formed by fold lines 57, 58 with the fold line portion 33 comprised between points 36a and 38a: ßl = ß2 + (TX -?). The angles a and? they make it possible to design the fold lines 43 and 45. The point of intersection between the fold lines 52 and 66 can be determined when calculating the angle? formed by the portion 67 of the line 66 with the fold line portion 31 comprised between the fold lines 43 and 59. In particular, the angle? it's a function of the angle ? , which is formed by the fold line 45 with the fold line 43 after the folding of the triangular finishing portion 4 has been completed and the panel A is superimposed on all the other panels. The angle ? it can be calculated as follows: a - (? 2 - a) Y = > 2 where angle? 2 can be obtained by means of the formula ._ l? ? 2 = 2 arcsen (). li Therefore, the following formula can be determined when calculating the angle?: C / 2 a - (2 arcsen () - oc li? = 2 Knowing the angle?, It is possible to design the portion 67 of the fold line 66 and obtain the position of the intersection point between the fold lines 52 and 66. The portion 68 of the fold line 66 can be obtained by joining the previous intersection point with the intermediate point 61. Figure 8 shows another example of a triangular splash pack denominated with a number 1 'and that can be obtained according to the method described above by varying the values of the upper angle and the length 1 of the upper sloping wall 10. The advantages of packages 1 and 1 'according to the present invention will be clear from the following description. In particular, by simply placing the condition that the formation of the lateral upper walls 18, 19 of the package 1, 1 'is obtained by means of the rotations of the panels A, B, C, D, E, F, G of the Laminar packaging material 2 as rigid bodies around their respective fold lines, it is possible to differentiate the size and shape of the triangular finishing portion 4 insofar as an adequate folding of the packing material and a correct packing closure is ensured. Furthermore, thanks to the fact that the folding of the different parts (panels A, B, C, D, E, F, G of the packaging material 2) of the packaging material 2 is obtained by means of rotations and therefore without deformations In the case of relevant and consequent efforts, the integrity of the aluminum layer, which is much less flexible than the other layers of the packaging material, is not compromised during the formation stages. Clearly, changes can be made to the gaskets 1, 1 'as described and illustrated herein without departing from the scope of the appended claims. In particular, it will be understood that the main portion 3 of the packages 1, 1 'comprised between the edges 21, 22 and the fold lines 31, 32 can have any design form. In addition, in each fin area 46, 47, the portion 68 of fold line 6566 can be defined at least in part by a pair of parallel lines having respective ends converging in a single line towards the relative intermediate point 60, 61. In this way, in the area of the portion 68 of the lines of fold 65, 66, the deformation of the packing material due to the thickness of the overlapping panels is reduced. It is noted that, with regard to this date, the best method known to the applicant to carry out the aforementioned invention is that which is clear from the present description of the invention.

Claims (11)

1. CLAIMS Having described the invention as above, the claim contained in the following claims is claimed as property: 1. A triangular top pack for flowable food products produced by folding and sealing a laminar packing material and comprising a triangular top portion that includes a front and rear sloping top wall joined together in an upper transverse seal and a pair of lateral upper walls joining the respective lateral edges of the upper front and rear sloping walls, each of the lateral upper walls is obtained by folding a portion respective of the sheet wrapping material along predetermined fold lines delimiting a number of panels, characterized in that the fold lines are determined between a plurality of possible fold lines designed in such a way that the formation of the lateral upper walls is effect by means of rotations of the panels as rigid bodies around their respective fold lines.
2. 2. The pack according to claim 1, characterized in that the fold lines desired to form the lateral upper walls are obtained by choosing at least the value of an upper angle formed along each lateral upper wall, between opposite edges. of them converging to the upper transverse seal and the value of the length of one of the upper, inclined front and rear walls along a direction transverse to the upper transverse seal.
3. The package according to claim 1 or 2, characterized in that it is obtained from an intermediate package having a prismatic main portion and at least a portion of the tapered end delimited by the upper transverse seal, which defines the upper inclined front walls. and rear and provided with opposing, prominent side wings designed to be folded from the upper volume of the package available for the food product to obtain the upper side walls.
4. The package according to claim 3, characterized in that each side flap has one side adjacent to one of the front and rear inclined upper walls and another side formed by a portion of the relative end of the upper transverse seal and placed adjacent to another of the upper sloping walls front and rear.
5. 5. A method for dimensioning a triangular finishing pack for flowable food products obtained by folding and sealing a laminar packaging material, the package comprising a triangular finishing portion including a front and rear inclined upper wall joined together in an upper transverse seal and a pair of lateral upper walls that join the respective lateral edges of the upper front and rear sloping walls and obtained by folding respective portions of the laminar packing material along predetermined fold lines delimiting a number of panels , the method is characterized in that it comprises the step of determining the position and extension of the fold lines in such a way that the formation of the lateral upper walls is effected by means of rotations of the panels as rigid bodies around their respective fold lines .
6. The method according to claim 5, characterized in that the step of determining the position and extension of the fold lines is carried out after a step of selecting the desired values of at least one upper angle formed, throughout of each lateral upper wall, between opposite edges thereof converging to the upper transverse seal and of the length of one of the upper front and rear sloping walls along a direction transverse to the upper transverse seal.
7. The method according to claim 6, characterized in that the step of determining the position and extension of the fold lines comprises the step of designing, in a portion of the laminar packing material intended to form the triangular end portion of the packing : a first line of transverse fold that delimits the upper transverse seal; - a second line of transverse fold forming the horizontal corners of the triangular end portion and placed at a distance from the first transverse fold line equal to the chosen length; - a number of longitudinal fold lines delimiting, together with the first and second transverse fold lines, a pair of first zones defining the lateral upper walls and a pair of second zones defining the upper and rear inclined upper walls, the longitudinal fold lines form with the respective portions of the second transverse fold line, external to the first zones, respective angles equal to the upper angle chosen; and - a number of internal fold lines that are located within each first zone and whose orientation is determined by means of geometric relationships obtained when considering that the resulting panels have to be rotated as rigid bodies during the formation of the triangular end portion .
8. The method according to claim 7, characterized in that the internal fold lines comprise, for each first zone, a pair of first inclined fold lines, joined in the first line of transverse fold defining an isosceles triangle with the second transverse fold line, the method is characterized in that the step of designing the internal fold lines in each first zone comprises the step of calculating the angle formed by each first inclined fold line with the portion of the second transverse fold line defining one side of the isosceles triangle, by means of the formula: 1 ß = arctg () c / 2 where c represents the width of the packing to be formed.
9. The method according to claim 8, wherein the internal fold lines comprise, for each first zone, three second inclined fold lines extending from an intermediate point located within the isosceles triangle to the respective vertex thereof, characterized because the step of designing the internal fold lines comprises the step of calculating the angle (ß2) formed by the second fold lines inclined with respect to the first inclined fold lines by means of the formula: ß - (? a - 0 ) ß2 = 2 where? represents the angle formed between each longitudinal fold line and the first adjacent inclined fold line, while? i represents the angle formed by each longitudinal fold line with the portion of the second transverse fold line defining one side of the isosceles triangle , after the folding of the triangular finishing portion has been completed.
10. The method according to claim 9, wherein the internal fold lines comprise, for each first zone, a third inclined fold line extending from the intermediate point to the first transverse fold line, which intersects with one of the first fold lines inclined and divided by one of the first fold lines inclined in a first and a second portion to form between the same angles different from 180 degrees and located to the outside and inside of the isosceles triangle, respectively, characterized in that the step of designing the internal fold lines comprises the step of calculating the angle (?) formed by the first portion of the third fold line inclined with the portion of the first cross fold line located within each first zone by means of of the formula: C / 2 a - (2 arcsen () - a li? B, 2 where li represents the length of the pli lines egue longitudinal.
11. 11. A laminated packaging material adapted to be folded along predetermined fold lines and sealed to produce a triangular top seal for flowable food products, characterized in that the fold lines are dimensioned according to the compliance method with any of claims 5 to 10.