Method for manufacturing a flan for packaging a portion of food

Abstract

The invention relates to a method for manufacturing a blank formed from a complex (2) comprising an outer layer (3) based on cellulosic fibers and an inner sealing substrate (4) comprising at least one outer layer (4a) associated with the outer layer (3), said method comprising forming at least one tear line (33) by ablation of material using a laser beam with a wavelength between 9.6 and 10.6 μm, at least the outer layer (4a) being formed from a material whose absorption of said laser beam is less than that of the outer layer (3) and / or whose reflectivity of said laser beam is greater than 50%, said laser beam being configured to induce at least partial ablation of only the outer layer (3). Figure 4

Description

Title of the invention: Method for manufacturing a flan for packaging a portion of food

[0001] The invention relates to a method for manufacturing a flan for packaging a portion of food, as well as a flan obtained by implementing such a method.

[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 wrapper formed by folding a flan.

[0003] To obtain an envelope, in particular of quadrilateral or prismatic geometry with a triangular base, blanks are known on which fold lines are formed to delimit different panels which, after folding, form a wall of the envelope.

[0004] The flan includes at least one sealing layer having oxygen and / or water vapor barrier properties, and the closure of the packaging must preserve this sealing in order to guarantee the preservation of the packaged portion.

[0005] To achieve this sealing while benefiting from environmentally friendly packaging, in particular by facilitating its recycling after consumption of the food portion, the flan is formed of a complex comprising an outer layer based on cellulosic fibers which is combined with an inner substrate ensuring mainly the sealing function, in particular against oxygen and / or water vapor.

[0006] In relation to such a design of flans, there arises the problem of the antagonism between the ease of opening the packaging in order to consume the portion, in particular by young children and / or for soft portions, and the aforementioned sealing constraints which require a robust flan and closure.

[0007] To overcome this problem, document WO-2023 / 148163 provides for the formation of at least one tear line arranged so that a manual pull induces a tear in said blank for the purpose of opening it.

[0008] In particular, a tear line can be formed by laser ablation over approximately 4 / 5 of the total thickness of the outer layer, which allows a good compromise between preserving the sealing of the packaging and the ease of opening it by tearing along said lines.

[0009] To do this, the laser beam can be configured to be absorbed by the outer layer based on cellulosic fibers so that the absorbed energy is transformed into heat and changes its state, melting or vaporizing it to a greater or lesser depth.

[0010] However, in relation to the costs and production rates imposed by the food industry In the case of a mental laser, which can be in the order of 1,000 flans per minute, the sole control of the parameters of an industrial laser does not allow to guarantee the depth of ablation, risking in particular damage to the sealing substrate and therefore compromising the proper preservation of the packaged portion.

[0011] The invention aims to improve the prior art by proposing in particular a method for manufacturing a blank comprising a layer based on cellulosic fibers in which at least one tear line is formed by laser ablation, said method making it possible to obtain a good compromise between the depth of ablation necessary to facilitate the opening and the preservation of the functional sealing substrate.

[0012] To this end, according to a first aspect, the invention proposes a method for manufacturing a flan for packaging a portion of food, said flan being formed of a complex comprising an outer layer based on cellulose fibers and an inner sealing substrate comprising at least one outer layer associated with the outer layer, said method providing for: - to form folding lines on said blank to allow its conformation into an envelope in which said portion can be packaged before closing said envelope; - form at least one tear line arranged so that a manual pull induces a tear in said blank for the purpose of opening it;

[0013] the tear line being formed by ablation of material by means of a laser beam at a wavelength between 9.6 and 10.6 μm, said method providing that at least the outer layer of the sealing substrate is formed of a material whose absorption of said laser beam is less than that of the outer layer and / or whose reflectivity of said laser beam is greater than 50%, said laser beam being configured to induce at least partial ablation of only the outer layer.

[0014] According to a second aspect, the invention provides a flan for packaging a portion of food, said flan being formed of a complex comprising an outer layer based on cellulose fibers and an inner sealing substrate comprising at least one outer layer associated with the outer layer, said outer layer being formed of a material whose absorption to a laser beam with a wavelength between 9.6 and 10.6 μm is less than the absorption of the outer layer and / or whose reflectivity to said laser beam is greater than 50%, said flan being manufactured according to such a process as to include: - folding lines allowing its conformation into an envelope in which said portion can be packaged before closing said envelope; - at least one tear line arranged so that a manual pull induces a tear of said flannel for the purpose of opening it, said tear line being formed by at least partial removal of only the outer layer.

[0015] Other features and advantages of the invention will become apparent from the following description, made with reference to the accompanying figures, in which:

[0016] [Fig-1] schematically represents, in front view, a blank according to a method of production readiness before folding;

[0017] [Fig.2] represents in perspective the side of the [Fig.1] during its folding to form a package;

[0018] [Fig.3] represents, in perspective top view, the opening of the packaging of the [Fig.2];

[0019] [Fig.4] schematically represents in partial view a complex for forming a blank according to an embodiment of the invention, said complex having several pre-cut lines of different depths.

[0020] In relation to these figures, a process for manufacturing a flan for packaging a food portion 1 is described below, as well as a flan obtained by implementing such a process.

[0021] The flan is particularly suitable for packaging an individual portion 1 of fresh dairy product, for example fresh and / or processed cheese.

[0022] The blank is formed of a complex 2 which has an outer layer 3 based on cellulosic fibers, as well as an inner sealing substrate 4 comprising at least an outer layer 4a associated with the outer layer 3.

[0023] The outer layer 3 can be made from cellulosic fibers derived from wood and shaped by papermaking to form a layer of paper or cardboard, or be in the form of a non-woven material.

[0024] Such an arrangement makes it possible to benefit from environmentally friendly packaging design. In particular, the outer layer 3 can be made from recycled cellulose fibers.

[0025] According to one embodiment, the outer layer 2b has a surface mass between 30 g / m2 and 150 g / m2, in particular between 50 g / m2 and 110 g / m2, and more particularly in the order of 80 g / m2.

[0026] Advantageously, the complex 2 comprises between 60% and 90% by weight of cellulosic fibers. To this end, the outer layer 3 may have a thickness of approximately 60 µm, and the inner substrate 4 a thickness of between 4 µm and 20 µm.

[0027] In particular, the inner substrate 4 has oxygen and / or water vapor tightness properties which are sufficient to guarantee the preservation of the packaged portion 1.

[0028] To improve the overall properties of the packaging, complex 2 can include at least one additional layer, for example in the form of a film and / or varnish, with suitable properties.

[0029] In particular, as shown in [Fig.4], the outer face of the outer layer 3 can be coated with a first additional layer 5 of varnish with anti-condensation properties, the outer face of which can itself be coated with a second additional layer 6 of permanent heat-sealable varnish.

[0030] Complex 2 may have decorations and / or markings, for example patterns and / or inscriptions of an aesthetic and / or commercial nature related to the food portion 1. These elements may be formed by printing and / or embossing directly on the outer layer 3 made of cellulosic fibers.

[0031] According to one embodiment, the outer layer 4a of the substrate 4 has oxygen and / or water vapor tightness properties.

[0032] As a possibly complementary alternative, the substrate 4 comprises at least one inner layer 4c associated with the outer layer 4a opposite the outer cellulosic layer 3, said inner layer having properties of impermeability to oxygen and / or water vapor.

[0033] In particular, the outer layer 4a may have barrier properties essentially to oxygen or water vapor, the inner layer 4c having complementary barrier properties to ensure sealing.

[0034] In relation to [Fig. 4], the sealing substrate 4 comprises: - an outer layer 4a based on polyethylene which has properties of sealing essentially to water vapor; - an inner 4c layer based on ethylene-vinyl alcohol (EVOH), which has essentially oxygen-tight properties; - an opposing layer 4b associated with the inner layer 4c opposite the outer layer 4c, made of polyethylene to protect said inner layer.

[0035] Furthermore, to allow the formation of the packaging and its closure after packaging of the food portion 1, the sealing substrate 4 has a sealing layer 4d arranged opposite the outer cellulosic layer 3, in particular on the inner face of the layer 4b.

[0036] Advantageously, the 4d sealing layer is made of a food-grade material so that it can come into contact with the food portion 1 during packaging formation. To this end, the 4d sealing layer can be based on a peelable and / or heat-sealable varnish, for example, based on polylactic acid (PLA).

[0037] We now describe the manufacture of a flan formed from a complex 2 as described above and the packaging of a food portion 1 in said flan.

[0038] The manufacturing process first involves forming lines of folding 7 arranged to allow the shaping of said flan into an envelope 8, in which the food portion 1 can be packaged before closing said envelope to form a package.

[0039] The folding lines can be configured to obtain an envelope, in particular of quadrilateral or prismatic geometry with a triangular base, by delimiting different panels which, after folding, form a wall of said envelope.

[0040] Advantageously, these folding lines 7 are formed by grooving the outer layer 3 made of cellulosic fibers, which makes it easier to fold the blank while preserving the integrity of the sealing substrate 4.

[0041] In relation to the figures, the process provides for forming on the blank fold lines arranged to allow the folding of said blank into a prismatic envelope 8 with a triangular base.

[0042] To achieve this, the process involves forming such lines 7 on the side so as to define: - a side panel 9 of quadrilateral geometry intended to form a side wall 10 of the envelope 8; - two panels respectively lower 11 and upper 12 of triangular geometry each having an internal edge which is connected by a fold line 7a to respectively a large external side of the lateral panel 9, said lower and upper panels being intended to form respectively a lower wall and an upper wall 13 of the envelope 8; - two side panels 14 each having a quadrilateral geometry having an internal edge which is connected by a fold line 7b to respectively an external side of a lower panel 11 and upper panel 12, said side panels being intended to form together a side wall 15 of the envelope 8; - a border having two outer bands 16 each having an inner edge which is connected by a fold line 7d to respectively an outer edge of a side panel 14, said outer bands being arranged to be sealed to each other to form a sealing back 17 of the side wall 15 of the envelope 8; - a rear panel 18 having a front edge which is connected by a fold line 7c to a rear edge of the lower 11, side 9, 14 and upper 12 panels, said rear panel being intended to form a rear wall of the envelope 8.

[0043] The lower panel 11 and upper panel 12 each have an isosceles triangle geometry, the base of which forms the rear edge which is defined by the fold line 7c separating said lower panel from the rear panel 18.

[0044] The outer bands 16 of the border extend to the rear edge 19 of the blank, and the border has a rear band 20 which extends between the rear ends of said outer bands and all along the rear edge 19 of said blank, said rear band being connected by a fold line 7e to a rear edge of the rear panel 18, being arranged to be sealed on itself to form a sealing hem of the rear wall of the package.

[0045] In the embodiment shown, the packaging provides for folding the blank along its folding lines 7a, 7b, 7c, 7d, 7e to form a prismatic envelope 8 with a triangular base having a lower wall, two side walls 15, a top wall 13 and an open rear mouth 21.

[0046] To do this, it is planned to fold successively: - lines 7a defining the large external sides of the side panel 9, so as to erect the lower panels 11 and upper panels 12 to form the lower and upper walls 13 of the envelope 8; - lines 7b defining the respective external edges of the lower panel 11 and upper panel 12, so as to fold down the side panels 15 opposite the side panel 9 to form the side wall 15 of the envelope 8; - the lines 7d defining the respective external edges of the side panels 14, so as to erect the external bands 16 of the border by arranging their respective internal faces against each other ([Fig.2]).

[0047] In particular, at the end of these folding steps, an envelope 8 is obtained with an open rear mouth 21 ([Fig.2]), and the inner face of the rear band 20 of the border delimits an inner periphery of said rear mouth.

[0048] The packaging then provides for sealing the outer bands 16 of the border, in particular by sealing on itself, by a "flesh-to-flesh" type association, the sealing layer 4d covering the respective inner faces of said outer bands, so as to form a sealing backing 17 of the side wall 15 of the envelope 8.

[0049] In particular, as the outer bands 16 extend to the rear edge 19 of the side, their sealing makes it possible to obtain a sealing backbone 17 which closes the periphery of the rear mouth 21.

[0050] Next, the dorsal 17 is folded down onto the lateral wall 15 of the envelope 8 after it has been sealed.

[0051] The food portion 1 can then be packaged in the packaging through the rear mouth 21, before folding the rear panel 18 to close said mouth.

[0052] Thus, a mold is formed by means of the envelope 8, into which the food portion 1 can be poured in liquid or viscous form before closing said envelope, thereby limiting production costs by eliminating a additional step of shaping said food portion before packaging.

[0053] This arrangement also allows for the production of food portions 1 that are packaged more hygienically and with better preservation conditions. Indeed, by pouring the food portion 1 directly into its individual packaging, its exposure to ambient air is limited, thus reducing the risk of contamination, particularly by germs. Furthermore, if the food portion 1 is poured at a temperature higher than the pasteurization temperature, this further improves its preservation properties.

[0054] To fold the rear panel 18, the method involves extending the fold lines 7a, 7b and / or 7d defining the external and internal edges of the lower 11, side 9, 14 and upper 12 panels onto said rear panel, so as to form lower 22, side 23 and upper 24 sectors, said folding being carried out by folding the side sectors 24 flat to fold down the upper 24 and lower 22 sectors, as shown in [Fig.2].

[0055] In order to be able to close the mouth 21 in a watertight manner, the process then involves: - folding the rear band 20 flat, by placing an upper portion of the inner face of said rear band on a lower portion of said inner face; - seal the inner face of the back strip 20, by a "flesh-to-flesh" type association of its upper and lower portions, in order to form the sealing hem of the back wall.

[0056] This embodiment allows in particular a continuous sealing of the inner face of the rear band 20, guaranteeing optimal sealing due in particular to the absence of any excess thickness in said sealing.

[0057] In the embodiment shown, the method involves extending the fold lines 7a, 7b and / or 7d of the rear panel 18 onto the rear band 20 of the border, so as to form on said rear band lower 25, lateral 26 and upper 27 sectors in the rear extension of the corresponding sectors 20, 21, 22 of said rear panel.

[0058] Thus, the flat folding of the rear strip 20 is achieved by placing the inner face of the upper sector 27 on the inner face of the lower sector 25, and by folding the inner face of each of the lateral sectors 26 onto itself.

[0059] In particular: - the various folding lines 7a, 7b and / or 7d are extended in a straight line, which facilitates the manufacture of the blank and the folding of the envelope 8; and - the respective lateral sectors 23, 26 of the rear panel 18 and the strip

[0060]

[0061]

[0062]

[0063]

[0064]

[0065]

[0066] The back 20 are equipped with folding line patterns arranged to allow them to fold flat. In particular, the folding lines formed on and near the lateral sectors 23, 26 are arranged to allow the folding of said sectors into lateral bellows of triangular geometry, the sealing of the rear opening 21 then being carried out: - by folding said triangular gussets inwards towards the packaging and on either side of the rear wall, then sealing the rear strip 20 "flesh-to-flesh", the sealing hem thus formed then being folded over a lower portion of the rear wall of the envelope 8; or - by folding said triangular gussets outwards from the packaging and then, after sealing “flesh-to-flesh” the back band 20 and folding the sealing hem on the back wall, by folding each of said outer gussets down onto the adjacent side wall 15. To facilitate opening the packaging, particularly by young children and / or in relation to a soft food portion 1, the process provides for forming the fold lines so that the flan also has a front panel 28, which has a rear edge connected by a fold line 7f to a front edge of the outer bands 16 and the side panels 9, 14. Each of the fold lines 7a defining the external edges of the central side panel 9 extends to the front edge 29 of the front panel 29, forming, on either side of said line, an external sector 30, in the continuation of an external side panel 14 and an adjacent external band 16, and a central internal sector 31. In particular, the top of each of the upper 12 and lower 11 panels opens onto the intersection between the internal sector 31 and one of the external sectors 30. In relation to [Fig.2], the front panel 28 is intended to be sealed to form, in the extension of the spine 17, a sealing tab 32 for the tip of the packaging. To do this, the process involves sealing the portion of layer 4d covering the inner face of the front panel 28 to itself, so as to allow the formation of the tongue 32 by "flesh-to-flesh" sealing of said front panel. To finalize the formation of the envelope 8, the process involves, after sealing the lateral spine 17 and the front tab 32: - fold the dorsal 17 onto the lateral wall 15 of the envelope 8, so as to position horizontally the external part of the tab 32, formed by sealing the external sectors 30; - fold the protruding part of the tongue 32 forward onto the other side wall from the tip of the packaging.

[0067] The method involves forming on the blank at least one tear line 33 arranged so that a manual pull on the tab 32 induces a tear in said blank for the purpose of opening it.

[0068] In relation to figures 1 to 3, the tear line 33 has two lateral segments 33a extending over the upper panel 12 along respectively a lateral edge of said panel, from a rear area to a front area of ​​said panel, each of the segments 33a extending from said front area to the outer edge of an outer band 16 by crossing a lateral panel 14.

[0069] Thus, the tear line 22 is arranged so that a manual pull on the sealing tab 32 induces a tear in the side on either side of its tip, followed by a propagation of said tear on either side of the upper wall 12.

[0070] This arrangement makes it possible to provide the consumer with a package with a rigid tab 32 whose large dimensions make it easier to grasp digitally, said tab also forming a lever arm to facilitate the initiation of the tear of said package along the line 33 formed for this purpose in said package.

[0071] In particular, each lateral segment 33a of the tear line 33 extends parallel to respectively a lateral edge of the upper panel 12, which allows the consumer to open the packaging on either side of the front point and on the upper wall 13 of the envelope 8, and in particular outside the sealing spine 17, which is offset on a lateral wall 15 of said envelope, by being crossed on its front area by a portion of the tear line 33.

[0072] Thus, the consumer does not need to open the spine 17 to open the packaging, which makes it possible to optimize the sealing of said spine during the 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 33 on a front area of ​​said spine.

[0073] Advantageously, the lateral segments 33a of the tear line 33 delimit between themselves and on the upper wall 12 of the envelope 9 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.

[0074] To achieve this, each lateral segment 33a extends in particular over more than 90% of the length of the adjacent upper lateral edge, while having an intrinsic length which remains less than 100% of said lateral edge length, in order to guarantee the separation of the tip from the rest of the packaging when it is opened.

[0075] Thus, the tear line 33 makes it possible to form in the envelope 8 a large opening to facilitate the extraction of the food portion 1 from the packaging.

[0076] In particular, each lateral segment 33a of the tear line 33 extends along the adjacent upper lateral edge, forming a band 34 between them, such that, after opening the packaging, each band 34 rests on an upper wall of the food portion 1, thereby holding a lateral wall 15 of the wrapper 8 to which it is attached in support. This arrangement allows the food portion 1 to be laterally held against the lower wall of the wrapper 8, pending its removal by the consumer, as shown in [Fig. 3].

[0077] Each of the strips 37 has a width that is less than 10% of the width of the side panel 9 or the sum of the widths of the adjacent side panel 14 and outer edge 16, and in particular less than 5% of said width or sum of widths. This arrangement makes it easier for the consumer to remove the food portion 1, who simply has to pull the side panels 15 apart to remove said food portion from the bottom wall of the wrapper while maintaining its shape, particularly in the case of a soft food portion 1.

[0078] Each lateral segment 33a has, at the junction between its front extension on the corresponding lateral panel 9, 14, a connecting elbow of curved geometry, the radius of curvature of which is arranged to guarantee a tear all along said segments.

[0079] Each lateral segment 33a of the tear line 33 extends in a straight line to the rear edge of the upper panel 12, and continues in particular on the rear panel 18, as shown in [Fig.2].

[0080] Thus, by continuing his pulling effort on the tab 32, the consumer can partially, but not totally, tear the back wall of the envelope 8, so as to keep the food portion 1 between the untorn back wall portion and the side walls 15, while waiting for the consumer to extract said food portion from the packaging.

[0081] Furthermore, the lower panel 11 is devoid of a tear line, in order to remain attached to the envelope 8 after opening the packaging, thus forming a tray on which the food portion 1 can be held until it is taken by the consumer.

[0082] The tear line 33 is obtained by partially removing material from the thickness of the blank, to a sufficient depth to form a weakening line that guides the tear of said blank along said line. Advantageously, the line 33 can be formed by laser cutting with different parameters at the connecting bends described above, in order to facilitate tearing along said bends.

[0083] The process involves forming the tear line 33 by removing material from the by means of a laser beam with a wavelength between 9.6 and 10.6 pm, in particular by means of a carbon dioxide laser beam with a wavelength close to 10.6 pm.

[0084] This solution allows the use of an industrial laser whose beam parameters can be configured so that the energy absorbed by the cellulosic fiber-based layer 3 is sufficient to melt or vaporize said layer to a greater or lesser depth in order to form the tear line 33.

[0085] In particular, the laser beam is configured to induce the formation of the tear line 33 by at least partial ablation of only the outer layer 3, insofar as ablation of the substrate 4 would be detrimental to the seal.

[0086] Advantageously, the laser beam is configured to ablate more than 80% of the thickness of the outer layer 3, in particular substantially 100% of said thickness, which allows a good compromise between preserving the sealing of the packaging and the ease of opening it by tearing along the tear line 33 thus formed.

[0087] Indeed, as shown in [Fig.4], a line 33' formed by laser cutting along too shallow a depth leaves an outer layer 3 of cellulosic fibers too thick to be easily torn along said line.

[0088] Conversely, a 33” line formed by laser cutting to a depth that is too great, in particular greater than the total thickness of the outer layer 3, alters the integrity of the substrate 4, and therefore potentially the sealing properties of the packaging.

[0089] According to the invention, at least the outer layer 4a of the substrate 4 is formed of a material whose absorption to the laser beam is less than that of the outer layer 3 and / or whose reflectivity to said laser beam is greater than 50%.

[0090] Thus, in the case where the laser beam would come upon the outer layer 4a, for example due to the energy dispersions of said laser beam and / or the thickness and / or the density of the outer layer 3, the low absorption and / or the high reflectivity of said beam by the outer layer 4a makes it possible to avoid its damage.

[0091] Advantageously, the sealing substrate 4 in its entirety exhibits an absorption to the laser beam which is lower than that of the outer layer, so as to guarantee its total integrity and therefore the sealing it confers.

[0092] According to one embodiment, the substrate 4 and / or the outer layer 4a of said substrate has an absorption to the laser beam which is less than 50% of the absorption of the outer layer 3, and in particular less than 10%.

[0093] In particular such transparency can be obtained with an external layer 4a formed from polyolefin, in particular a polyolefin which belongs to the family of polyethylenes.

[0094]

[0095]

[0096] In particular, as shown in [Fig. 4], the sealing substrate 4 preferably comprises, from the outside in: - an outer layer 4a made of polyethylene; - an inner 4c layer based on EVOH; - an opposing layer 4b based on polyethylene; - a food-grade 4D sealing layer, notably acid-based polylactic. Alternatively or complementarily, the outer layer 4a exhibits a laser beam reflectivity greater than 80%, and in particular greater than 90%. In particular, such reflectivity can be obtained with an outer layer 4a based on metallic material, especially aluminum-based, or whose outer face is covered with a metallic film.

Claims

Demands

1. A method for manufacturing a flan for packaging a portion of food (1), said flan being formed of a complex (2) comprising an outer layer (3) based on cellulosic fibers and an inner sealing substrate (4) comprising at least one outer layer (4a) associated with the outer layer (3), said method comprising: - forming fold lines (7a, 7b, 7c, 7d, 7e, 7f) on said flan to allow its conformation into a wrapper (8) in which said portion can be packaged before closing said wrapper; - forming at least one tear line (33) arranged so that a manual pull induces a tear in said flan for the purpose of opening it;said method being characterized in that the tear line (33) is formed by ablation of material by means of a laser beam at a wavelength between 9.6 and 10.6 μm, said method providing that at least the outer layer (4a) of the sealing substrate (4) is formed of a material whose absorption of said laser beam is less than that of the outer layer (3) and / or whose reflectivity of said laser beam is greater than 50%, said laser beam being configured to induce at least partial ablation of only the outer layer (3).

2. A method according to claim 1, characterized in that it provides that the outer layer (4a) of the sealing substrate (4) is formed from polyolefin.

3. A process according to claim 2, characterized in that it provides that the polyolefin belongs to the polyethylene family.

4. A method according to any one of claims 1 to 3, characterized in that it provides that the outer layer (4a) of the substrate (4) has oxygen and / or water vapor tightness properties.

5. A method according to any one of claims 1 to 4, characterized in that it provides that the substrate (4) comprises an internal layer (4c) that is impermeable to oxygen and / or water vapor.

6. A method according to claim 5, characterized in that it provides a sealing substrate (4) comprising an outer layer (4a) based on polyethylene, an inner layer (4c) based on ethylene-vinyl alcohol (EVOH) and an opposing layer (4b) based on polyethylene.

7. A method according to any one of claims 1 to 6, characterized in that it provides that the sealing substrate (4) has a sealing layer (4d) disposed opposite the outer layer (3).

8. A method according to any one of claims 1 to 7, characterized in that it provides that the outer layer (4a) of the substrate (4) has a laser beam reflectivity that is greater than 80%, in particular greater than 90%.

9. A method according to any one of claims 1 to 8, characterized in that it provides that the sealing substrate (4) has an absorption to the laser beam which is lower than that of the outer layer (3).

10. A method according to any one of claims 1 to 9, characterized in that it provides for a substrate (4) and / or an outer layer (4a) of said substrate whose absorption to the laser beam is less than 50% of the absorption of the outer layer (3).

11. A method according to claim 10, characterized in that it provides for a substrate (4) and / or an outer layer (4a) of said substrate whose absorption to the laser beam is less than 10%.

12. A method according to any one of claims 1 to 11, characterized in that the laser beam is configured for ablation of more than 80% of the thickness of the outer layer (3), in particular substantially 100% of said thickness.

13. A flan for packaging a portion of food (1), said flan being formed of a complex (2) comprising an outer layer (3) based on cellulose fibers and an inner sealing substrate (4) comprising at least one outer layer (4a) associated with the outer layer (3), said outer layer being formed of a material whose absorption to a laser beam of a wavelength between 9.6 and 10.6 μm is less than the absorption of the outer layer (3) and / or whose reflectivity to said laser beam is greater than 50%, said flan being manufactured according to a process according to any one of claims 1 to 12 to comprise: - folding lines (7a, 7b, 7c, 7d, 7e, 7f) enabling its formation into a wrapper (8) in which said portion can be packaged before closing said wrapper; - at least one tear line (33) arranged so that a manual drawing induces a tear in said blank in view of its opening, said tear line being formed by at least partial removal of only the outer layer (3).

14. Flan for packaging a portion of food (1) according to the reven dication 13, characterized in that the complex (2) comprises between 60% and 90% by weight of cellulosic fibers.

15. Flan for packaging a portion of food (1) according to one of the following claims 13 or 14, characterized in that the outer layer (3) has a thickness of approximately 60 pm, the inner sealing substrate (4) having a thickness between 4 pm and 20 pm.

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