FR2918969A1 - Corn grain packaging and cooking device for preparing pop corn in microwave oven, has slot provided at level of wall of compensation zone, where device is in complex material that does not includes packaged layer perpendicular to slot - Google Patents

Abstract

The device (10) has a compensation zone (16) occupying a retracted position in which the zone forms a cover for a rigid base (14) to define a restricted volume, and an extended position in which the zone forms a tube to define a large volume adapted to a pop-corn volume after cooking. A sealed and flexible plastic layer i.e. polyethylene terephthalate layer, is placed on a face oriented towards an interior of the device in a complex material. A slot (32) is provided at the level of a wall of the zone. The complex material does not include a packaged layer perpendicular to the slot.

Description

DEVICE FOR PACKAGING AND COOKING CORN GRAINS FOR

MANUFACTURE OF POP CORN

  The present invention relates to a device for packaging and cooking including corn kernels for making popcorn. More generally, this device is suitable for all foods whose cooking leads to a significant increase in volume.

  Document WO 2004/032633 discloses such a device comprising a first container with a substantially rigid base in the lower part surmounted by a compensation zone capable of occupying a first folded position in which it forms the lid of the base in order to delimiting a restricted volume adapted to the maize grains and a second extended position in which it forms a tube extending the side walls of the base in order to define a larger volume adapted to the volume of the popcorn after cooking. The compensation zone comprises four side walls in the extension of the side walls of the base, two opposite walls, called retractable walls, comprising a median fold line parallel to the bottom at half height, the two other opposite walls, called stiffening walls, comprising a first median fold line parallel to the bottom half height and second fold lines cross. The tube generally has a flared shape. To obtain the deployment of the compensation zone, it is necessary to provide at the level of the stiffening walls at the median fold line a cutout to allow the deployment of the compensation zone. Indeed, it is not possible to go from the folded state to the deployed state without this cut. To close the tube, the compensation zone comprises in the upper part shutters for closing the device.

  According to this document, since the tube is not tight because of the presence of the cuts at the level of the stiffening walls, the corn kernels are placed in a tray and are covered with a film glued with a hot melt glue against the side walls of the tube. the tray, the latter being placed in the first container whose restricted volume is adapted to the tray.

  When cooked, the blackberries burst and turn into popcorn. At the same time, the film dissociates from the tray to release the popcorn. The cooking ends when all the grains have burst and no more grain burst while making noise.

  Even if this conditioning device is satisfactory, it can be improved. According to a first disadvantage, it is necessary to provide two disjoint elements namely a first container forming a tube and a second container forming a tray. These two elements require for each a mechanical device to achieve them. Moreover, during the production process, it is necessary to place the tray in the tube. This phase must be done by hand or requires a complex mechanization. According to another disadvantage, the film of the tray is mixed with the popcorn at the end of cooking which is not very appetizing. In addition, this hot film can cause burns if the user removes too early or without protection. According to another disadvantage, the flexible film can bend during bonding with the tray so that the junction between the film and the tray is not perfect and can leave small gaps. The latter can cause leakage of fatty substances to the outside which soak the first container or air to the inside of the tray which then oxidizes food which results in a reduction in the use-by date. Finally, according to a last disadvantage, the microwave ovens used for cooking having disparate powers, it is difficult to determine a cooking time. For now, the user can only trust his ear and stop cooking when he no longer hear bursts of grain. Also, there is no way to conveniently indicate the end of cooking. Also, the present invention aims at overcoming the drawbacks of the prior art by proposing a conditioning and cooking device, in particular for moisture-resistant micis grains and allowing safe use. For this purpose, the subject of the invention is a conditioning and cooking device adapted to popcorn comprising in the lower part a substantially rigid base and in the upper part a compensation zone 15 capable of occupying a first folded position in which it forms a lid for the base to delimit a restricted volume and a second extended position in which it forms a tube to delimit a larger volume adapted to the volume of the popcorn after cooking, characterized in that it is made from a complex material comprising a layer of cardboard material to provide rigidity and a flexible and impervious plastic layer disposed on the inwardly facing face of the device, and in that it comprises at least one wall of the compensation area a window, the complex material having no layer of cardboard material in line with said at least one window. The present invention is described in detail with reference to the accompanying drawings which show a preferred but nonlimiting embodiment, the figures corresponding to FIG. 1, a view of the device for presenting and cooking grains of maize according to the present invention. in the unfolded position, - Figure 2, a view of the same device in the folded position, - Figure 3, a view of the upper part of the device after cooking, - Figure 4, a section illustrating a sheet in which is cut a blank for FIG. 5 is a view illustrating a first variant of a blank for obtaining the device of the invention; FIG. 6 is a view illustrating another variant of a blank for obtaining the device according to the invention; FIG. 7 is a view illustrating another variant of a blank for obtaining the device of the invention; FIG. 8 is a view of a blank illustrating a first embodiment of a device; barquett 9a, a section illustrating the tray of FIG. 8 in the closed position, FIG. 9B, a section illustrating the tray of FIG. 8 in an open position in a first container, FIG. a blank illustrating another embodiment of a tray; FIG. 11A, a section illustrating the tray of FIG. 10 in the closed position, and FIG. 11B, a section illustrating the tray of FIG. opened. In FIGS. 1 and 2, there is shown at 10 a packaging and cooking device, especially corn kernels, for making popcorn. More generally, this device is suitable for all foods whose cooking leads to a significant increase in volume. For example, one could consider its use for cooking biscuits type puffs. This device 10 comprises a container 12 with a base 14 and a compensation zone 16 capable of occupying a first folded position in which it forms the cover of the base in order to define a restricted volume adapted to the maize grains and a second deployed position wherein it forms a tube extending the side walls of the base to define a larger volume adapted to the volume of the popcorn after cooking. The base is rectangular or square and rigid to a height of about 1 to 2 centimeters to fix ideas. The base comprises a bottom 18, which is also the bottom of the container 12 and four substantially rigid side walls 20. The compensation zone 16 is folded in FIG. 2, with nevertheless an unfolding primer so as to be able to distinguish the different parts. In the reality of the facts, the height of the whole appears to be substantially that of the height of the base. This compensation zone 16 comprises folds, respectively formed on the walls opposite said first walls 22 and second walls 24. The first walls 22 each comprise a fold 26 said middle fold, this fold being substantially in the middle of each faces of the first walls and parallel to the base. The second walls 24 each comprise several folds, a first fold 28 in the continuity of the folds 26, disposed in the middle of each of the faces of the second walls and parallel to the base and plies 30 said diagonals along the diagonals of the faces of the second walls. When the container 12 is in the folded state, the first walls are folded in two along the fold lines 26, for each first wall 22, the two parts disposed on either side of the fold line 26 being clad against each other. The second walls 24 deform along the fold lines 28 and 30 so as to form a bellows, for each second wall, the intersection of the fold lines 30 moving towards the inside of the container. Advantageously, the container 12 has an upwardly flared shape to obtain an inverted truncated pyramid. According to the invention, the container 12 is made of cardboard material to ensure rigidity with at least a second wall 24, and preferably on each second wall 24, a window 32 at the right of the intersection zone of the diagonal folds 30, said window 32 being closed by a flexible and tight material. According to one characteristic of the invention, the container is obtained from a blank 34 made of a complex material comprising a layer 36 of cardboard material to ensure the rigidity coated with a layer 38 of flexible and impervious plastic material, the complex n having no layer 36 of cardboard material to the right of the windows 32 but only a layer 38 of flexible plastic material and sealed, as shown in Figure 4. The layer 38 of plastic material is oriented towards the inside of the container and the layer 36 of cardboard material towards the outside of the container. In addition, the layers 36 and 38 are bonded together permanently so as not to become detached during cooking. This solution has the following advantages: It enables the container 12 to be sealed against the inner faces of the container being coated with a plastic layer. Thus it is possible to no longer use a tray as indicated in the prior art. Thus, only one container is made. The presence only of the plastic layer 38 at the windows 32 allows the passage from one state to another, in particular from the folded state to the unfolded state.

  As an indication, the window 32 is centered on the second wall and at a height of the order of 50 mm and a width of the order of 115 mm. According to a preferred embodiment, the plastic layer 38 is transparent in order to be able to visualize the grains of corn during cooking.

  The layer 38 of plastic material may be PET or polyethylene terephthalate. According to one embodiment, the fold lines 26, 28 and 30 are obtained by creasing the blank of complex material or by cutting and / or continuous or discontinuous precut only of the layer 36 of cardboard material.

  The container 12 may optionally comprise deployment means comprising two tongues, one per first face 22, each tongue advantageously being T-shaped, the transverse branch being bonded directly to the outer faces of the first walls 22. According to one embodiment of FIG. embodiment, the container 12 comprises means 40 of opening / closing. These means 40 comprise two flaps 42 folding, the flaps being connected by a fold line 44 to two side walls 22 or 24 opposite. In the closed position, these flaps 42 are connected to each other and to the compensation zone 16 so as to obtain a sealed enclosure, the connections being hot melt so as to break when the temperature exceeds a certain threshold, during cooking. According to one embodiment, the free ends of the flaps 42 may comprise flaps 46 whose inner faces, coated with a layer 38 of plastics material, are thermofusibly bonded, the flaps 46 glued to each other being then folded against the outer face of one of the flaps 42. The side edges of the flaps 42 may be extended by flaps 48 pressed against the outer faces of the side walls of the corresponding compensation zone 16 so as to obtain a tight seal.

  According to one embodiment, the opening / closing means 40 additionally comprise first flaps 42, second flaps 50 connected by fold lines 52 to opposite side walls 24 or 22 to which the first flaps 42 are not connected. The flaps 48 which comprise only the layer 38 of plastic material, are hot-melt glued against the inner faces of the second flaps 50 which are coated with a layer 38 of plastic material. The second flaps 50 are then folded against the outer face of the first flaps 42 as illustrated in Figures 1 and 2.

  Depending on the case, the second flaps 50 have a greater or lesser height. According to one variant, the flaps 42 and 50 have a height adapted so that, when they are in the complete open position, the free ends of said flaps are arranged close to the upper face of the furnace enclosure in order to prevent the popcorn from jumping outside the first container 12. According to one embodiment, the first flaps 42 are interconnected by a tab 54 which prevents the complete opening of said flaps 42. This tab 54 comprises a pre-cut 56 to break said tab 54 and allow the complete opening of the flaps 42.

  Alternatively, the flaps 42 and 50 can be detached from the rest of the container. The operation of the opening and closing means 20 is as follows: In the closed position, the flaps 42 and 50 are folded as illustrated in FIGS. 1 and 2. During cooking, the connections between the flaps 42 on the one hand and between the flaps 42 and 50 are desoldering. During cooking, the volume of the popcorn tends to increase causing the opening of the first flaps 42. This opening of the first flaps 42 is braked, the second flaps 50 tending to remain in the folded position and to prevent the opening of the first flaps 42. This opening movement can also be controlled by the tongue 54 which prevents the complete opening of said first flaps 42 in order to keep the popcorn inside the container 12, as illustrated in FIG. the height of lifting depending in particular on the length of the tongue 54. The raising of the flaps can be used to indicate the end of cooking. The bottom 18 of the container can be made in the same way as the means 40 of opening / closing, the links not being in the case of hot melt but permanent background.

  According to a preferred embodiment and illustrated in Figures 5 and 6, the bottom 18 comprises four flaps 58 and 58 'each connected to a side wall 20 of the base 14, two flaps 58' arranged opposite each other having fold lines for obtaining bellows. According to this embodiment, the flaps 58 and 58 'are connected in pairs by fold lines 60 and comprise at their free ends flaps 62. The flaps 58' each comprise a fold line 64 of which the tip of the Ve is disposed in the median position at the fold line connecting said flaps 58 'to the flaps 62 corresponding and whose ends of the branches of the Vee are connected to the corners of the bottom 18. According to this embodiment, the flaps 58 'are disposed above the flaps 58 inside the container. To keep the bottom closed in a sealed and permanent manner, the inner faces of the flaps 62 connected to the flaps 58 are glued against each other, and the flaps thus glued are folded against the outer face of one of the flaps. 58. To glue or weld the elements, it is possible to use an insert element such as a hot-melt glue or not as required, or no insert, the plastic faces of the complex being heated and then pressed against each other. in the liaison areas. In order to obtain a definitive weld or a hot-melt weld which breaks during firing, the temperature rise is adjusted during welding. By way of example, for a complex with a PET or polyethylene terephthalate face, an elevation of greater than or equal to approximately 270 ° C is achieved to obtain a non-reversible welding and a temperature rise of the order of 180 ° C. to obtain a reversible welding and obtain a hot-melt bond. The complex used to form the container may comprise at certain zones a layer 66 of electromagnetic wave absorbing material. According to an embodiment illustrated in FIG. 5, the side walls 20 of the base and possibly the lower part of the walls 22 and 24 of the compensation zone comprise a layer 66 made of absorbent material, shown hatched. According to another embodiment illustrated in FIG. 6, only certain portions of the flaps 58 and 58 ', in particular the angular portions visible from the inside of the container at the inner face of the bottom 18, comprise a layer 66 made of absorbent material, represented hatched.

  To form a tube, the walls 20 and 22 are connected in pairs by fold lines, and one of the side walls comprises a flap 68 for connecting to another side wall. According to the invention, there is obtained a device comprising a single element, namely a sealed container which does not require the presence of a second container or a detachable film capable of causing burns. According to the invention, a tube is first made by ensuring a permanent connection between the flap 68 and the corresponding side wall.

  The bottom is formed by also making permanent type connections. The compensation zone is then in the deployed position. Following, filling the container 12 with grains of corn. The dimensions of the base are adapted to the volume of the maize.

  The container is closed by means of hot melt type connections. The container 12 is then deformed so as to arrange the compensation zone in the folded position. The packaging devices are then packaged in the folded state in a plastic film which keeps them in this state. The devices can be stored individually or in groups. To cook the popcorn, the user takes the device out of its packaging and then introduces it into a microwave oven. The cooking of the first grains leads to an increase in pressure inside the device which then unfolds, the latter being sealed. During cooking, the opening / closing means 40 are desoldering. At the end of cooking, the opening / closing means rise slightly to indicate the end of cooking. Just remove the device from the oven and draw the popcorn without the need to remove a burning film and unappetizing. FIG. 7 shows a blank 100 for obtaining a packaging device according to the invention. The references common to the preceding variants are increased by 100. This blank comprises a substantially central bottom 118 of substantially square shape, with at each side side walls 120 forming the substantially rigid base 112. the first and second walls 122 and 124 are connected to the side walls 120 by fold lines. Unlike previous blanks, the bottom is made in one piece and all the walls 122 and 124 have a common side with said bottom, the latter being arranged in the manner of petals. As before, the first and second walls 122 and 124 comprise fold lines 126, 128, 130 and windows 132.

  To form the packaging device, the side walls 120 and the first and second walls 122 and 124 are straightened so as to delimit a container. The device obtained preferably comprises the same means 140 of opening / closing as previously described. Thus, the first and second flaps 142 and 150 are provided at the upper ends of the first and second walls 122 and 124. Flaps 146 are also provided at the flaps 142 to ensure the connection between said flaps. Similarly, flaps 148 are also provided to ensure the connection between the first flaps 142 and second flaps 150. As before, these bonds are preferably hot melt. A tab 154 with a precut 156 may be provided to connect the shutters 142. In addition, the device may comprise deployment means as previously described.

  According to this embodiment, to provide the connection between the first and second walls 122 and 124, bellows 170 are provided to connect them in pairs. Each bellows 170 comprises two triangular portions, each triangular portion having a first common side with an edge of a wall 122 or 124 and a second common side with the other triangular portion of the same bellows 170.

  These bellows 170 extend from the bottom 118, over the entire height of the walls 122 and 124. This configuration makes it possible to obtain a container with reinforced sealing insofar as no welding is provided in the lower part. In addition, according to this embodiment, the necessary welds are of a single type ie hot melt to use a simple complex with a single plastic film. According to this embodiment, the bellows 170 are folded inside the container, the outer faces of the triangular parts being pressed against each other. By following, the bellows thus folded are folded against the first walls 122. Thus, two bellows 170 are folded against each first wall 122. To obtain the compensation zone, the bellows 170 comprise fold lines 172 which are arranged at the fold lines 126 when the bellows 170 are folded against the first walls 122. To maintain the bellows 170 against the walls 122, for each pair of bellows 170 pressed against the same wall 122, connecting means are provided between the bellows 170 of the same pair to keep them plated.

  For each pair of bellows 170 pressed against the same wall 122, a first bellows 170 comprises a flap 174 capable of ensuring the connection between the two gussets being folded down, the upper portion of the second bellows 170 not carrying the flap 174 being interposed between said flap 174 and the first bellows 170. However, the invention is not limited to this embodiment of the connecting means between bellows. To facilitate folding, the fold lines can be obtained by cutting the cardboard layer of the complex only, the plastic layer sealing and binding between the different parts of the layer of cardboard material.

  Even if the container 12 is sealed, a second container can be included in the form of a tray 70. In Figures 8, 9A, 9B, 10, 11A and 11B, various embodiments of said tray are shown.

  The tray 70 is made from a blank cut in a complex comprising at least two contiguous sheets, one rigid paper or cardboard, the other plastic sealing material such as for example polyethylene.

  Advantageously, the complex comprises, in at least one zone, a layer of electromagnetic wave absorbing material called susceptor. The tray 70 is made from a blank comprising a first portion forming a container adapted to receive the maize grains and any other ingredients and at least a second part forming a pivoting lid connected to the first part on the one hand, by at least one folding line forming a hinge, and secondly, by a hot-melt connection so as to form a sealed enclosure in a first state said closed state and allow the pivoting of the cover to allow the expansion of the pop- corn in a second state said open state, after breaking the hot-melt connection when the temperature exceeds a certain threshold. This arrangement makes it possible to obtain a sealed enclosure ensuring better preservation of the products. Furthermore, the fact of providing at least one pivoting lid always connected to the container and pressed against the walls of the compensation zone 16 in the open state makes it possible to increase the safety, the user no longer having to withdraw a hot element such as a film. Finally, this arrangement makes it possible to obtain a more appetizing product, no longer any element to be removed being mixed with the popcorn in the manner of a film of the prior art. Preferably, the tray 70 is disposed in the first container so that said pivoting lid is pressed against one of the first face walls 22. The lid may optionally detach from the rest of the tray 70 by a line of pre-cut.

  In the other figures 8, 9A and 9B, there are shown variants having the advantage of providing surfaces for bonding or welding the cover in the same plane and one or more cover (s) plane (s) which simplifies this operation and to increase the quality of the seal thus obtained.

  This tray 70.1 comprises a container 200 with a bottom 202, side walls 204 and gussets 206 bent outwardly of the container. This tray also comprises a cover 208 connected by a fold line 210 to one of the side walls 204 and possibly the bellows 206 adjacent to said wall 204. The cover has a width extending beyond the side wall, substantially also to that of the side wall and the two adjacent bellows. In addition, the tray 70.1 comprises flaps 212 connected by a fold line 214 to the side walls not connected to the lid 208 which are not folded against the outer face of the side walls but bent substantially at 90 relative to said side walls to the outside and are arranged in the same plane substantially parallel to the bottom 202. To facilitate the shaping of the container 200 and the flaps 212, bellows 216 are provided, each having a common side with a first bellows 206 and a flap 212. These bellows 216 are formed above the flaps 212 and folded over the flaps so as to connect the flaps 212 between them. The implementation of this tray is as follows: Initially, the container 200 is formed by gluing or welding the bellows 206. This welding or gluing is preferably resistant to heat and is not hot melt. Following this operation, the side walls are straightened. Following, the flaps 212 are bent at 90 and the bellows 216 are formed. They are then folded and glued welded to the shutters 212. As before, this welding or gluing is preferably resistant to heat and is not hot melt.

  After filling the container, operated horizontally, the lid is closed by gluing or welding it thermofusibly against the flaps 212. According to this embodiment, it is noted that the flaps 212 participate in the wedging of the tray 70.1 in the first container .

  According to an improvement, it can be provided at the corners a third bellows 218 which is formed and folded under the flaps 212. This component reduces the risk of leakage. Advantageously, the lid 208 is glued to the container all along its periphery. Thus, the four sides of the cover are glued against the flaps 212 and a flap 220 interposed between a side wall 204 and the cover 208. This solution provides substantially the same resistance to the opening for the entire periphery of the cover. According to another improvement, the cover 208 comprises at the side opposite to that at which said cover 208 is connected to the rest of the tray a protruding portion 222 which extends or not over the entire length of said side so as to maintain the cover 208 in the closed position and to curb its opening in order to obtain a sudden and rapid complete opening. This configuration makes it possible to limit the risk of a popcorn being placed between the lid 208 and the wall of the first container in order to prevent the lid from opening completely, which could cause excessive cooking of certain grains. In Figure 9A, the tray is shown in the closed position. Note that the side of the lid 208 near its articulation with the rest of the tray is also glued.

  In Figure 9B, the tray is shown in the open position in a first container. Note that the lid is pressed against one of the walls of said first container and to dimensions adapted to said container including height so that the free end of the lid is close to the upper part of the first container to limit the risk of seeing a popcorn interposed between the lid and the side wall of said first container. The cover 208 may comprise at the side edges of the flaps. Advantageously, these flaps are in two independent parts whose shapes are adapted to the first container to limit the risk of seeing a popcorn come to interpose between said lid and the side wall of the first container. According to another improvement, the flaps 212 are widened to go up along the side walls of the first container, as shown in Figure 9B. In Figures 10, 11A, and 11B, there is shown a second embodiment for filling in a vertical position of a tray 70.2. This tray comprises a container 400 with a bottom 402, square or rectangular, four side walls 404 connected to the four sides of the bottom 402 by fold lines, the side walls 404 being connected in pairs by bellows 406 participating in the seal of the tray.

  When the side walls 404 are arranged vertically, the bellows 406 are formed outside the container and then folded on the outer face of the walls so as to keep them perpendicular to the bottom 402. This tray also comprises a lid 408 connected by a line of folding 410 to one of the side walls 404.

  According to this embodiment, the cover 408 comprises a central portion 420 whose dimensions are substantially identical to those of the bottom 402 and four flaps 422, one at each side, each being capable of cooperating with a side wall 404. Advantageously the shutters 422 are connected two by two at the corners by bellows 424. According to this embodiment, the flaps 422 are glued at the upper edge of the side walls 404, so that said flaps are bent at 90 and oriented upwardly relative to the central portion 420, the latter being offset downwardly relative to the upper end of the side walls 404.

  In the closed position, the bellows 424 are pinched between the two parts of the bellows 406 to ensure a good seal. In practice, the lid 408 is closed on three sides. Only the flap 422 opposite the junction line 410 is not glued. The container is filled in a vertical position. At the end of the filling, the last flap 422 is bonded to the corresponding side wall 404. To glue or weld the elements, it is possible to use an insert such as a hot-melt glue or not as required, or no insert, the plastic faces of the complex used to form the tray being heated and then plated against each other. the other in the liaison areas. In order to obtain a definitive weld or a hot-melt weld which breaks during firing, the temperature rise is adjusted during welding. By way of example, for a complex with a PET or polyethylene terephthalate face, an elevation of greater than or equal to approximately 270 ° C is achieved to obtain a non-reversible welding and a temperature rise of the order of 180 ° C. to obtain a reversible welding and obtain a hot-melt bond. Regarding the complex, the latter comprises a layer of material absorbing electromagnetic waves at the bottom of the tray only.

Claims (9)

  1. Packaging and cooking device adapted to the popcorn comprising in the lower part a substantially rigid base (14) and in the upper part a compensation zone (16) capable of occupying a first folded position in which it forms a cover for the base to delimit a restricted volume and a second extended position in which it forms a tube to delimit a larger volume adapted to the volume of the popcorn after cooking, characterized in that it is made from a complex material comprising a layer (36) of cardboard material to provide rigidity and a layer (38) of flexible and impervious plastic material disposed on the inwardly facing face of the device and in that it comprises at least one wall of the compensation zone (16) a window (32), the complex material having no layer (36) of cardboard material to the right of the window (32).   2. Packaging and cooking device according to claim 1, characterized in that the compensation zone (16) comprises first walls (22) opposite each comprising a median fold line (26) and second walls (24) comprising each having a middle fold line (28) and diagonal fold lines (30) and in that each second wall (24) comprises a window (32) at the intersection of the diagonal fold lines (30), the complex material having no layer (36) of cardboard material at right of the window (32).   3. Packaging and cooking device according to claim 1 or 2, characterized in that the layer (38) of plastic material is transparent.   4. Packaging and cooking device according to any one of the preceding claims, characterized in that it comprises means (40) for opening and closing comprising two flaps (42) and links between said flaps (42). ) and between said flaps (42) and the compensation zone (16) of hot melt type to break when the temperature exceeds a certain threshold, during cooking.   5. Packaging and cooking device according to claim 4, characterized in that the means (40) for opening and closing comprise first flaps (42) and second flaps (50) and in that said first flaps comprise at the side edges of the flaps (48) comprising only the plastic layer capable of being glued against the inner faces of the second flaps (50).   6. Packaging and cooking device according to claim 4 or 5, characterized in that the free ends of the first flaps (42) comprise flaps (46) whose inner faces, coated with a layer (38) of plastic , are hot-melt glued.   7. Packaging and cooking device according to any one of claims 4 to 6, characterized in that it comprises a tongue (56) for controlling the opening of the flaps (42).   8. Packaging and cooking device according to any one of the preceding claims, characterized in that it comprises to form the bottom (18) four flaps (58, 58 ') connected in pairs by fold lines (60 ), two opposed flaps (58 ') having a V-fold line so as to form a bellows fold.   9. Packaging and cooking device according to any one of the preceding claims, characterized in that the complex material comprises at least some areas a layer (66) of electromagnetic wave absorbing material.