Blank for packaging a food portion in a prismatic envelope with a triangular base

Abstract

The invention relates to a blank comprising fold lines (6a, 6b, 6c, 6d, 6e, 6f, 6g, 6h, 6i, 6j) which define: a quadrilateral side panel (4), two triangular lower (7) and upper (8) panels, a rear panel (14) and an edge having two outer strips (12) to form a sealing backing and a front panel (27) arranged to form, in the extension of the backing, a sealing tab, a tear line (31) being arranged so that manual pulling on the tab induces a tear of said blank on either side of its tip, then on either side of said upper panel. Figure 1

Description

Title of the invention: Blank for repackaging a food portion in a prismatic envelope with a triangular base

[0001] The invention relates to a blank for packaging a food portion, as well as to a method of packaging a food portion using such a blank.

[0002] It applies in particular to the packaging of individual food portions of fresh dairy products, such as for example fresh and / or processed cheese, which are packaged in a prismatic envelope with a triangular base formed by folding a blank.

[0003] To benefit from an ecologically designed packaging, the blank according to the invention is preferably formed from a complex comprising an outer layer based on cellulose fibers and an inner sealing layer.

[0004] To obtain a prismatic envelope with a triangular base, blanks are known which are provided with folding lines which are arranged so as to define: - a side panel of quadrilateral geometry intended to form a side wall of the envelope; - two panels, respectively lower and upper, of triangular geometry, each having an internal edge which is connected by a fold line to respectively a large external side of the side panel, said lower and upper panels being intended to form respectively a lower wall and an upper wall of the envelope; - two side panels each having a quadrilateral geometry presenting an internal edge which is connected by a fold line to respectively an external side of a respectively lower and upper panel, said side panels being intended to form together a side wall of the envelope; - a rear panel having a front edge which is connected by a fold line to a rear edge of the lower, side and upper panels, said rear panel being intended to form a rear wall of the envelope.

[0005] The blank also comprises a border having two outer strips each having an inner edge which is connected by a fold line to respectively an outer edge of a side panel, said outer strips being arranged to be sealed to each other to form a sealing backing of the side wall of the envelope.

[0006] The backing makes it possible to guarantee the sealing of the packaging but, in particular in relation to a blank comprising a cellulose layer, the problem arises of the ease of opening the packaging in order to be able to consume the portion, in particular by young children and / or for soft portions.

[0007] In particular, opening and / or tearing the backing requires handling of the packaging which, in addition to complex ergonomics, proves too restrictive for preserving the integrity of the portion.

[0008] The invention aims to improve the prior art by proposing a blank, in particular comprising a cellulose layer, for packaging a food portion, said blank making it possible to combine optimal sealing with good opening ergonomics, in particular in relation to ease of opening for young children and / or the packaging of a soft portion.

[0009] To this end, according to a first aspect, the invention proposes a blank for packaging a food portion comprising folding lines allowing the shaping of said blank into a prismatic envelope with a triangular base in which said portion can be packaged before closing said envelope, said folding lines defining a blank having: - a side panel of quadrilateral geometry intended to form a side wall of the envelope; - two panels, respectively lower and upper, of triangular geometry, each having an internal edge which is connected by a fold line to respectively a large external side of the side panel, said lower and upper panels being intended to form respectively a lower wall and an upper wall of the envelope; - two side panels each having a quadrilateral geometry presenting an internal edge which is connected by a fold line to respectively an external side of a respectively lower and upper panel, said side panels being intended to form together a side wall of the envelope; - a border having two outer strips each having an inner edge which is connected by a fold line to respectively an outer edge of a side panel, said outer strips being arranged to be sealed to each other to form a sealing backing for the side wall of the envelope; - a rear panel having a front edge which is connected by a fold line to a rear edge of the lower, side and upper panels, said rear panel being intended to form a rear wall of the envelope; - a front panel having a rear edge which is connected by a fold line to a front edge of the outer strips and the side panels, said front panel being intended to be sealed to form, in the extension of the back, a sealing tab for the tip of the packaging;

[0010] the blank comprising a tear line having two lateral segments extending on the upper panel along respectively a side edge of said panel from a rear area to a front area of ​​said panel, each of the segments extending from said front area to the outer edge of an outer strip crossing a side panel, said tear line being arranged so that a manual pull on the sealing tab induces a tear of said blank on either side of its tip followed by a propagation of said tear on either side of the upper wall.

[0011] According to a second aspect, the invention provides a method of packaging a food portion using such a blank, said method providing: - fold the blank along its fold lines to form a prismatic envelope with a triangular base having a lower wall, two side walls, an upper wall and an open rear mouth; - seal the outer edge strips and the front panel to form a sealing backing for the side wall of the envelope and a sealing tab for the tip of the packaging; - condition the portion in the packaging through the rear mouth; - close the said mouth tightly.

[0012] Other features and advantages of the invention will appear in the following description, given with reference to the appended figures, in which:

[0013] [Fig-1] schematically represents, in front and interior view, a blank according to a embodiment before folding;

[0014] [Fig.2a],

[0015] [Fig.2b],

[0016] [Fig.2c],

[0017] [Fig.2d],

[0018] [Fig.2e] and

[0019] [Fig.2f] represent in perspective following different orientations the blank of [Fig.l] during different stages of its folding to form a package;

[0020] [Fig.3a],

[0021] [Fig.3b] and

[0022] [Fig.3c] represent in perspective following different orientations different stages opening of the packaging of [Fig.2f].

[0023] In connection with these figures, a blank for packaging a food portion 1 is described below, as well as a method of packaging a food portion 1 using such a blank.

[0024] The flan is particularly suitable for packaging an individual portion of fresh dairy product, for example fresh and / or melted cheese.

[0025] The blank is formed from a complex 2 which has a sealing layer 2a with oxygen and / or water vapor barrier properties, in order to guarantee the preservation of the packaged food portion 1.

[0026] The sealing layer 2a may be made of a food-grade plastic material, in particular in the case where it is intended to be in contact with the food portion 1 packaged in the packaging. To do this, the sealing layer 2a may be made from polyethylene (PE) and / or polyethylene terephthalate (PET), or from other known types of food-grade plastics, such as a polyamide (PA), a polypropylene (PP) or a polylactic acid (PLA).

[0027] Advantageously, the complex 2 comprises an inner sealing layer 2a as described previously, as well as an outer layer 2b based on cellulose fibers. In particular, the cellulose fibers may be derived from wood and be shaped by the papermaking process to form a layer of paper or cardboard, or be in the form of a non-woven fabric.

[0028] Such an arrangement makes it possible to benefit from an ecologically designed packaging. In particular, the outer layer 2b can be made from recycled cellulose fibers.

[0029] According to an exemplary embodiment, the outer layer 2b has a surface mass of between 30 g / m2 and 150 g / m2, in particular of between 50 g / m2 and 110 g / m2, and more particularly of the order of 80 g / m2.

[0030] Advantageously, the complex 2 comprises between 60% and 90% by weight of cellulose fibers. For this purpose, the outer layer 2b may have a thickness of the order of 60 μm, and the inner layer 2a a thickness of between 4 μm and 20 μm.

[0031] To improve the overall sealing properties of the packaging, the complex 2 may comprise at least one additional layer of film and / or varnish having suitable properties, in particular a barrier to oxygen and / or water vapor. In particular, the outer face of the outer layer 2b may be coated with an additional layer of varnish with anti-condensation properties.

[0032] The complex 2 may have decorations and / or markings, for example patterns and / or inscriptions of an aesthetic and / or commercial nature linked to the food portion 1. These elements may be formed by printing and / or embossing directly on the outer layer 2b of cellulose fibers.

[0033] A method of packaging a food portion 1 in a blank formed in a complex 2 as described above is now described.

[0034] The method firstly provides for forming on the blank fold lines 6a-6j arranged to allow the shaping of said blank into a prismatic envelope 3 with a triangular base, in which the food portion 1 can be packaged before closing said envelope to form a package.

[0035]

[0036]

[0037]

[0038]

[0039] Advantageously, these fold lines 6a-6j are formed by creasing the outer layer 2b of cellulose fibers, which makes it easier to fold the blank while maintaining the integrity of the sealing layer 2a. In relation to the figures, the method provides for forming fold lines 6a-6j on the blank, so as to define there: - a side panel 4 of quadrilateral geometry intended to form a side wall 5 of the envelope 3; - two panels, respectively lower 7 and upper 8, of triangular geometry, each having an internal edge 7a, 8a which is connected by a fold line 6a to respectively a large external side 4b of the side panel 4, said lower and upper panels being intended to form respectively a lower wall and an upper wall 9 of the envelope 3; - two side panels 10 each having a quadrilateral geometry presenting an internal edge 10a which is connected by a fold line 6b to respectively an external side 7b, 8b of a respectively lower 7 and upper 8 panel, said side panels being intended to form together a side wall 11 of the envelope 3; - a border having two outer strips 12 each having an inner edge 12a which is connected by a fold line 6d to respectively an outer edge 10b of a side panel 10, said outer strips being arranged to be sealed to each other to form a sealing backing 13 of the side wall 11 of the envelope 3; - a rear panel 14 having a front edge 14a which is connected by a fold line 6c to a rear edge 7c, 4a, 8c, 10d of the lower 7, side 4, 10 and upper 8 panels, said rear panel being intended to form a rear wall 15 of the envelope 3. The lower 7 and upper 8 panels each have a geometry in the shape of an isosceles triangle, the base of which forms the rear edge 7c, 8c which is defined by the fold line 6c separating said lower panel from the rear panel 14. The outer strips 12 of the border extend to the rear edge 16 of the blank, and the border has a rear strip 17 which extends between the rear ends of said outer strips and all along the rear edge 16 of said blank, said rear strip being connected by a fold line 6e to a rear edge 14b of the rear panel 14, being arranged to be sealed on itself to form a hem 18 for sealing the rear wall 15 of the packaging. In relation to figures 2a to 2d, the packaging method provides for folding the blank along its fold lines 6a, 6b, 6c, 6d, 6e to form a prismatic envelope 3 with a triangular base having a lower wall, two side walls 5, 11, a wall upper 9 and an open rear mouth 19.

[0040] To do this, the method involves successively folding: - the lines 6a defining the large external sides 4b of the side panel 4, so as to erect the lower 7 and upper 8 panels to form the lower and upper walls 9 of the envelope 3 ([Fig.2a]); - lines 6b defining the respective external edges 7b, 8b of the lower 7 and upper 8 panels, so as to fold the side panels 10 opposite the side panel 4 to form the side wall 11 of the envelope 3 ([Fig.2b]); - the lines 6d defining the respective external edges 10b of the side panels 10, so as to erect the external strips 12 of the border by arranging their respective internal faces against each other (figures 2c, 2d).

[0041] In particular, at the end of these folding steps, an envelope 3 is obtained with an open rear mouth 19 (figures 2c, 2d), and the inner face of the rear strip 17 of the border delimits an inner periphery of said rear mouth.

[0042] The method then provides for sealing the outer strips 12 of the border, so as to form a sealing backing 13 of the side wall 11 of the envelope 3.

[0043] To do this, the method provides for depositing a layer of an adhesive on the respective inner faces of the outer strips 12, so as to form the sealing backing 13 by a “flesh-flesh” type sealing of said outer strips.

[0044] The adhesive may be a hot melt glue or a cold glue, so as to ensure a permanent and watertight seal of the backing 13.

[0045] In particular, since the outer strips 12 extend to the rear edge 16 of the blank, their sealing makes it possible to obtain a sealing backing 13 which closes the periphery of the rear mouth 19.

[0046] Then, as shown in [Fig.2c], the backing 13 is folded back onto the side wall 11 of the envelope 3 after it has been sealed.

[0047] The method then provides for packaging the food portion 1 in the packaging through the rear mouth 19, then folding the rear panel 14 to close said mouth.

[0048] Thus, the method makes it possible to form a mold by means of the envelope 3, into which the food portion 1 can be poured in liquid or viscous form before closing said envelope, which makes it possible to limit production costs by avoiding an additional step of shaping said food portion before packaging in the package.

[0049] This arrangement also makes it possible to produce food portions 1 packaged in a more hygienic manner and with better storage conditions. Indeed, By pouring food portion 1 directly into its individual packaging, its exposure to ambient air is limited, which limits the risk of contamination, particularly by germs. Furthermore, if food portion 1 is poured at a temperature higher than the pasteurization temperature, this further improves its preservation properties.

[0050] To fold the rear panel 14, the method provides for extending the fold lines 6a, 6b and / or 6d defining the outer edges 4b, 7b, 8b and / or 10b and inner edges 7a, 8a, 10a of the lower 7, side 4, 10 and upper 8 panels on said rear panel, so as to form lower 20, side 21 and upper 22 sectors therein, said folding being carried out by folding flat the side sectors 21 to fold down the upper 22 and lower 20 sectors, as shown in [Fig.2e].

[0051] In order to be able to close the mouth 19 in a sealed manner, the method then provides for: - folding the rear strip 17 flat, by placing an upper portion of the inner face of said rear strip on a lower portion of said inner face; - seal the inner face of the rear strip 17, by a “flesh-flesh” type association of its upper and lower portions, in order to form the sealing hem 18 of the rear wall 15.

[0052] This embodiment allows in particular continuous sealing of the inner face of the rear strip 17, guaranteeing optimal sealing due in particular to the absence of any excess thickness in said sealing.

[0053] To enable the rear strip 17 to be sealed, the method first provides for depositing a layer of adhesive on its inner face, in particular an adhesive similar to that placed on the outer strips 12 of the border to form the lateral sealing backing 13.

[0054] In the embodiment shown, the method provides for extending the fold lines 6a, 6b and / or 6d of the rear panel 14 onto the rear strip 17 of the border, so as to form on said rear strip lower 23, lateral 24 and upper 25 sectors in the rear extension of the corresponding sectors 20, 21, 22 of said rear panel.

[0055] Thus, as shown in [Fig.2e], the flat folding of the rear strip 17 is achieved by placing the inner face of the upper sector 25 on the inner face of the lower sector 23, and by folding the inner face of each of the lateral sectors 24 onto itself.

[0056] In particular, the different folding lines 6a, 6b and / or 6d are extended in a rectilinear manner, which makes it easier to manufacture the blank and fold the envelope 3.

[0057] The method provides for forming, on the respective lateral sectors 21, 24 of the panel rear 14 and rear strip 17, a pattern 6f of fold lines which is arranged to allow them to be folded flat.

[0058] In particular, as shown in Figures 1, 2a, 2b, 2c and 2d, each pattern of fold lines forms a triangle 6f extending over a lateral sector 21 of the rear panel 14, the base of the triangle 6f being formed by the front edge of said lateral sector and the apex of said triangle being arranged on the rear edge of said lateral sector, said apex being extended by a fold line 6g extending over the lateral sector 24 of the rear strip 17 to the rear edge 16 of said rear strip.

[0059] Advantageously, as shown in [Fig.l], the blank has a symmetry with respect to the axis defined by the fold line 6g of the lateral sector 24 located at the rear of the central lateral panel 4 (vertical in [Fig.l]), which makes it easier to manufacture said blank and to fold the envelope 3.

[0060] The method further provides for forming, on each of the upper sectors 22, 25 and lower sectors 20, 23: - an internal section 6h of fold line which extends from the intersection between the front edge and the internal edge of the upper sector 22 - respectively lower 20 - of the rear panel 14, to the rear edge 16 of the blank; and - an external section 6i of fold line which extends from the intersection between the front edge and the external edge of the upper sector 22 - respectively lower 20 - of the rear panel 14, to the rear edge 16 of the blank.

[0061] In relation to figures 2e and 2f, the different patterns 6f and sections 6h, 6i of folding lines formed on the lateral sectors 21, upper 22 and lower 20 of the rear panel 14 make it possible to fold said lateral sectors which forms two lateral gussets 26 of triangular geometry, each lateral sector 21 being folded towards the inside of the packaging and on either side of the rear wall 15.

[0062] In particular, after folding the side gussets 26, the rear strip 17 is sealed, then the sealing hem 18 thus formed is folded over a lower portion of the rear wall 15 of the envelope 3.

[0063] In a variant not shown, the sealing of the rear mouth 19 can be carried out by folding the lateral sectors 21 flat to form triangular gussets 26 which extend towards the outside of the packaging and then, after sealing the rear strip 17 and folding the sealing hem 18 onto the rear wall 15, by folding each of said external gussets onto the adjacent lateral wall 5, 11.

[0064] To facilitate the opening of the packaging, in particular by young children and / or in relation to a soft food portion 1, the method provides for forming the fold lines so that the blank further has a front panel 27, which has a rear edge 27a connected by a fold line 6j to a front edge 12b, 4c, 10c of the outer strips 12 and the side panels 4, 10.

[0065] Each of the fold lines 6a defining the external edges 4b of the central side panel 4 extends to the front edge 27b of the front panel 27, forming, on either side of said line, an external sector 28, in the extension of an external side panel 10 and an adjacent external strip 12, and a central internal sector 29.

[0066] In particular, the top of each of the upper 8 and lower 7 panels opens at the intersection between the internal sector 29 and one of the external sectors 28.

[0067] In relation to [Fig.2b], the front panel 27 is intended to be sealed to form, in the extension of the back panel 13, a sealing tab 30 for the tip of the packaging.

[0068] To do this, the method provides for depositing a layer of an adhesive, in particular similar to that used on the back 13 and the rear hem 18, on the inner face of the front panel 27, so as to allow the formation of the tab 30 by “flesh-flesh” type sealing of said front panel.

[0069] As shown in Figures 2c and 2d, the method provides, after sealing the upper backing 13 and the front tab 30, to: - fold the backing 13 onto the side wall 11 of the envelope 3, so as to arrange the external part of the tab 30 horizontally, formed by sealing the external sectors 29; - fold down onto the other side wall 5 the part of the tab 30 protruding in front of the tip of the packaging.

[0070] The method further provides for forming on the blank a tear line 31 which has two lateral segments 31a extending on the upper panel 8 along respectively a lateral edge 8a, 8b of said panel, from a rear zone to a front zone of said panel, each of the segments 31a extending from said front zone to the external edge 12c of an external strip 12 crossing a side panel 10.

[0071] The tear line 31 is arranged so that manual pulling on the sealing tab 30 causes the blank to tear on either side of its tip, followed by propagation of said tear on either side of the upper wall 9.

[0072] Thus, the blank makes it possible to provide the consumer with packaging with a rigid tab 30 whose large dimensions make it easier to grasp it with the finger, said tab also forming a lever arm to facilitate the initiation of tearing of said packaging along the line 31 formed for this purpose in said packaging.

[0073] In particular, each lateral segment 31a of the tear line 31 extends parallel to a respective lateral edge 8a, 8b of the upper panel 8.

[0074] This arrangement allows the consumer to open the packaging from either side of the front point and on the upper wall 9 of the envelope 3, and in particular outside the sealing backing 13, which is offset on a side wall 11 of said envelope, being crossed on its front zone by a portion of the tear line 31.

[0075] Thus, the consumer does not need to open the backing 13 to open the packaging, which makes it possible to optimize the sealing of said backing during storage of the packaged food portion 1 and to facilitate access to said food portion when opening its packaging, in particular thanks to the presence of a portion of the tear line 31 on a front zone of said backing.

[0076] Advantageously, the lateral segments 31a of the tear line 31 delimit between them and on the upper wall 9 of the envelope 3 a tearable zone whose surface area is greater than at least 80%, and in particular greater than 95% of the total surface area of ​​said upper wall.

[0077] To do this, each lateral segment 31a extends in particular over more than 90% of the length of the adjacent lateral edge 8a, 8b, while having an intrinsic length which remains less than 100% of said lateral edge length 8a, 8b, in order to guarantee the separation of the tip from the rest of the packaging when it is opened.

[0078] Thus, the tear line 31 makes it possible to form in the envelope 3 a large opening to facilitate the extraction of the food portion 1 from the packaging.

[0079] In particular, each lateral segment 31a of the tear line 31 extends along the adjacent lateral edge 8a, 8b, forming a strip 32 between them, so that, after opening the packaging, each strip 32 rests on an upper wall of the food portion 1, so as to keep a lateral wall 5, 11 of the envelope 3, to which it is attached, resting on it. This arrangement makes it possible to wedge the food portion 1 laterally on the lower wall of the envelope 3, while waiting for it to be extracted by the consumer, as shown in [Fig.3c].

[0080] Each of the strips 32 has a width which is less than 10% of the width of the side panel 4 or of the sum of the widths of the adjacent side panel 10 and outer edge 12, and in particular less than 5% of said width or of said sum of widths. This arrangement makes it easier for the consumer to extract the food portion 1, who then simply has to move the side walls 5, 11 apart to be able to remove said food portion from the lower wall of the casing 3 while retaining its shape integrity, in particular in the case of a soft food portion 1.

[0081] Each lateral segment 31a has, at the junction between its front extension on the corresponding lateral panel 4, 10, a connecting elbow of curved geometry, the radius of curvature of which is arranged to guarantee a tear along the entire length of said segments.

[0082] Each lateral segment 31a of the tear line 31 extends rectilinearly to the rear edge 8c of the upper panel 8, and extends in particular onto the rear panel 10, as shown in FIGS. 2a, 2b, 2c, 2d, 2e, 2f, 3a, 3c.

[0083] In a variant not shown, and in a particularly advantageous manner, the lateral segments 31a can each open into the adjacent fold line section 6h, 6i of the upper sector 22.

[0084] Thus, by continuing his pulling force on the tab 30, the consumer can partially, but not completely, tear the rear wall 15 of the envelope 3, so as to hold the food portion 1 between the untorn rear wall portion 15 and the side walls 5, 11, while waiting for the extraction of said food portion from the packaging by said consumer.

[0085] Furthermore, the lower panel 7 is devoid of a tear line, in order to remain attached to the envelope 3 after opening the packaging, thus forming a tray on which the food portion 1 can be held while waiting to be taken by the consumer.

[0086] According to one embodiment, the tear line 31 is obtained by partial pre-cutting of the thickness of the blank, in particular by ablation of material, to a sufficient depth to form a weakening line allowing the tearing of said blank to be guided along said line. Advantageously, the line 31 can be formed by laser cutting with a different parameter setting at the connection bends described above, in order to facilitate tearing along said bends.

[0087] To preserve the integrity of the inner layer 2a, and therefore the sealing of the packaging, the tear line 31 is formed by at least partial removal of only the outer layer 2b.

[0088] Advantageously, the tear line 31 is formed, for example by laser cutting or by mechanical cutting, over approximately 4 / 5 of the total thickness of the outer layer 2b, which allows a good compromise between preserving the sealing of the packaging and the ease of its opening by tearing along said line.

[0089] According to another embodiment, the tear line 31 allows the guiding of the tearing of the blank without prior pre-cutting of said blank, for example by means of a folding or grooving line of the blank, and / or a particular orientation of the fibers of the outer layer 2b along said line.

Claims

Claims

1. Blank for packaging a food portion (1) comprising folding lines (6a, 6b, 6c, 6d, 6e, 6f, 6g, 6h, 6i, 6j) allowing the shaping of said blank into a prismatic envelope (3) with a triangular base in which said portion can be packaged before closing said envelope, said folding lines defining a blank having: - a side panel (4) of quadrilateral geometry intended to form a side wall (5) of the envelope (3); - two panels, respectively lower (7) and upper (8), of triangular geometry, each having an internal edge (7a, 8a) which is connected by a fold line (6a) to respectively a large external side (4b) of the side panel (4), said lower and upper panels being intended to form respectively a lower wall and an upper wall (9) of the envelope (3); - two side panels (10) each having a quadrilateral geometry presenting an internal edge (10a) which is connected by a fold line (6b) to respectively an external side (7b, 8b) of a respectively lower (7) and upper (8) panel, said side panels being intended to form together a side wall (11) of the envelope (3); - a border having two outer strips (12) each having an inner edge (12a) which is connected by a fold line (6d) to respectively an outer edge (10b) of a side panel (10), said outer strips being arranged to be sealed to each other to form a sealing backing (13) of the side wall (11) of the envelope (3); - a rear panel (14) having a front edge (14a) which is connected by a fold line (6c) to a rear edge (7c, 4a, 8c, 10d) of the lower (7), side (4, 10) and upper (8) panels, said rear panel being intended to form a rear wall (15) of the envelope (3); said blank being characterized in that it comprises a front panel (27) having a rear edge (27a) which is connected by a fold line (6j) to a front edge (10c, 4c, 12b) of the outer strips (12) and the side panels (4, 10), said front panel being intended to be sealed to form, in the extension of the backing (13), a sealing tab (30) of the tip of the packaging, and in that said blank comprises a tear line (31) having two lateral segments (31a) extending on the upper panel (8) along respectively a lateral edge (8a, 8b) of said panel from a rear zone to a front zone of said panel, each of the segments (31a) extending from said front zone to the outer edge (12c) of an outer strip (12) crossing a side panel (10),said tear line being arranged so that manual pulling on the sealing tab (30) induces a tear in said blank on either side of its tip followed by propagation of said tear on either side of the upper wall (9).,

2. Blank for packaging a food portion (1) according to claim 1, characterized in that each lateral segment (31a) of the tear line (31) extends parallel to a respective lateral edge (8a, 8b).

3. Blank for packaging a food portion (1) according to one of claims 1 or 2, characterized in that each lateral segment (31a) of the tear line (31) extends along the adjacent lateral edge (8a, 8b) forming a strip (32) between them.

4. Blank for packaging a food portion (1) according to any one of claims 1 to 3, characterized in that each lateral segment (31a) of the tear line (31) extends to the rear edge (8c) of the upper panel (8).

5. Blank for packaging a food portion (1) according to claim 4, characterized in that each lateral segment (31a) of the tear line (31) extends onto the rear panel (14).

6. Blank for packaging a food portion (1) according to any one of claims 1 to 5, characterized in that the fold lines (6a, 6b, 6d) defining the external (4b, 7b, 8b, 10b) and internal (7a, 8a, 10a) edges of the lower (7), side (4, 10) and upper (8) panels extend, in particular in a rectilinear manner, on the rear panel (14) to form lower (20), side (21) and upper (22) sectors on said rear panel.

7. Blank for packaging a food portion (1) according to one of any of claims 1 to 6, characterized in that the border has a rear strip (17) which is connected by a fold line (6e) to a rear edge (14b) of the rear panel (14), said rear strip being arranged to be sealed on itself to form a sealing hem (18) of the rear wall (15) of the packaging.

8. Blank for packaging a food portion (1) according to claims 6 and 7, characterized in that the rear strip (17) has lower (23), lateral (24) and upper (25) sectors in the rear extension of the corresponding sectors (20, 21, 22) of the rear panel (14), the lateral sectors (21, 24) of the rear panel (14) and of the rear strip (17) each having a pattern (6f, 6g) of folding lines which is arranged to allow the flat sealing of the rear strip (17).

9. Blank for packaging a food portion (1) according to any one of claims 6 to 8, characterized in that the upper sector (22, 25) has an internal (6h) - respectively external (6i) - section of folding line extending from the intersection between the front edge and the internal - respectively external - edge of the upper sector (22) of the rear panel (10) to the rear edge (16) of the blank.

10. Blank for packaging a food portion (1) according to any one of claims 1 to 9, characterized in that it is formed from a complex (2) comprising an outer layer (2b) based on cellulose fibers and an inner sealing layer (2a).

11. Blank for packaging a food portion (1) according to claim 10, characterized in that the tear line (31) is formed by at least partial removal of only the outer layer (2b).

12. Blank for packaging a food portion (1) according to one of claims 10 or 11, characterized in that the folding lines (6a, 6b, 6c, 6d, 6e, 6f, 6g, 6h, 6i, 6j) are formed by creasing the outer layer (2b).

13. Method for packaging a food portion (1) using a blank according to any one of claims 1 to 12, said method providing for: - folding the blank along its fold lines (6a, 6b, 6c, 6d, 6e, 6f, 6g, 6h, 6i, 6j) to form a prismatic envelope (3) with a triangular base having a lower wall, two side walls (5, 11), an upper wall (9) and a rear mouth (19) open; sealing the outer strips (12) of the border and the front panel (27) to form a sealing backing (13) of the side wall (11) of the envelope (3) and a sealing tab (30) of the tip of the packaging; packaging the portion (1) in the packaging through the rear mouth (19); close the said mouth tightly.

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