FR2975973A1 - Waterproof cardboard tray for packaging products i.e. foodstuffs, has plastic film applied on inner face of cardboard sheet for connecting and maintaining central portion, tabs, cutouts, and peripheral edges in waterproof manner - Google Patents

Abstract

The waterproof cardboard tray according to the present invention is constituted firstly of a cardboard sheet (1) having in its corners A cutouts (2) for determining tabs (4, 5) each connected to a central portion (3) via a first bending rib (6), while said tongues (4, 5) comprise a second bending rib (7) for determining on each of said tabs (4, 5) an edge peripheral (8), and secondly a film (40) applied on the inner face of said cardboard sheet (1) for connecting and sealingly maintaining the profile of said tray (10) the part central (3), the tabs (4, 5), the cutouts (2) and the peripheral edges (8) so that said peripheral edges (8) are continuous, flat and without reliefs or extra thickness.

Description

Process for the production of a waterproof cardboard container for the production of packaging for the packaging of products

The present invention relates to a sealed package and a method of manufacturing a sealed cardboard tray for obtaining said packaging so as to be able to package various products.

Packages of this kind are known which consist of a preformed cardboard tray inside which is placed a plastic envelope also preformed for sealing the package. Note that the plastic envelope is not attached to the cardboard tray resulting in possible unexpected separations. Also the closing of the package is carried out via a seal which is fixed on the peripheral edges of the plastic casing.

Packaging is also known which consists of a cardboard container, at least one of whose faces and mainly that forming the inner part of the package which is covered before the conformation of said container with a food-grade varnish. tightness of the tray once consistent.

The shape of the tray is obtained by a particular folding and in particular in the corners so that the latter is sealed over its entire height. The sealed folding of the tray in the corners imposes at the level of the peripheral peripheral upper edges of the thickness preventing during the attachment of the lid to ensure a perfect seal between said lid and said tray.

The purpose of the packaging according to the present invention is to remedy the disadvantages of packaging known to date by ensuring, on the one hand, a perfect seal of the cardboard tray so that the latter can receive the packaging, for example from foodstuffs and foodstuffs. on the other hand a perfectly tight connection when fixing the lid on the flat peripheral edges of said tray avoiding any relief or thickening on said peripheral edges and more particularly in the corners of the cardboard tray.

The sealed cardboard tray according to the present invention consists on the one hand of a cardboard sheet having in its corners cutouts for determining tabs each connected to a central portion by means of a first bending rib , while said tongues comprise a second folding rib for determining on each of said tongues a peripheral edge, and secondly a film applied to the inner face of said cardboard sheet for connecting and sealingly holding according to the profile of said tray the central portion, the tabs, the cutouts and the peripheral edges so that said peripheral edges are continuous, flat and without reliefs or extra thickness.

The sealed cardboard tray according to the present invention comprises in the corners A of the cardboard sheet blanks which have with respect to a central axis of symmetry (a) a pencil-shaped profile.

The sealed cardboard tray according to the present invention comprises, in the corners A of the cardboard sheet, cutouts made which each consist of a first cut whose opposite edges are parallel to each other and parallel to the central axis (a) of said cut, and a second cut having opposite edges which are inclined and which extend those of the first cut towards the central portion.

The sealed cardboard tray according to the present invention comprises, when the cardboard sheet has a rectangular shape, a central axis (a) of the cuts which is inclined firstly by an angle α with respect to the diagonal (d) of the cardboard sheet passing through the center (o) of the latter and secondly at an angle 13 relative to the diagonal (d ') of the central portion passing through the center (o) and the tip of the cutout. pencil tip shape.

The sealed cardboard tray according to the present invention comprises, when the cardboard sheet is of square shape, a central axis (a) of cuts made in the angles A which is carried by the diagonals (d, d ') passing through the center ( o) of said cardboard sheet.

The sealed cardboard tray according to the present invention comprises first cutouts whose opposite edges are inclined at an angle Q close to 45 degrees with respect to a horizontal straight line (dh).

The sealed cardboard tray according to the present invention comprises cutouts made in each corner A of the cardboard sheet, the profile of which, when the latter is folded according to the first and second ribs, the opposite edges of each cutout respectively come against each other. the other edges with edges so that the peripheral edges are continuous, flat and without relief or overthickness.

The sealed cardboard tray according to the present invention comprises a central portion which can be deformed to form reliefs.

The sealed cardboard tray according to the present invention comprises a film which is made of a plastic material of density greater than or less than 1.

The waterproof cardboard tray according to the present invention comprises tabs comprising at the second ribs cutouts forming clips which are wrapped by the film to seal said cutouts. The sealed cardboard tray according to the present invention has planar peripheral edges which cooperate with a plastic or cardboard seal ensuring the tight closure of said tray for packaging products. The object of the present invention also relates to a method of manufacturing a waterproof cardboard tray by means of a cardboard sheet which consists of: - To take a cardboard sheet having folding ribs and in the corners A cuts for determining a central portion, tongues and peripheral edges, - arranging the pre-folded cardboard sheet inside a mold to the profile of the tray to be obtained, - applying to the cardboard sheet a film for assuring the assembly and sealing of the central portion, tabs, cutouts and peripheral edges between them, - To remove the tray from the mold.

The method of manufacturing the sealed cardboard tray according to the present invention is to heat the film to its softening temperature to allow it to deform upon evacuation of the mold.

The method of manufacturing the sealed cardboard tray according to the present invention is that the vacuum is obtained via the edge-to-edge fittings provided at the cutouts which allow the passage of the vacuum to press the film onto the entire surface of the cardboard sheet.

The following description with reference to the accompanying drawings, given by way of non-limiting examples, will provide a better understanding of the invention, the characteristics it has and the advantages that it is likely to provide:

Figure 1 is a top view illustrating the cardboard sheet previously cut for the realization of a tray according to the present invention.

Figure 2 is a schematic top view showing the position of the cutout in each corner of the cardboard sheet for making a tray according to the present invention.

Figures 3 and 4 are perspective views showing the placement of a sealed film inside the tray allowing the retention and binding of the edges to one another and sealing any the inner face of said cardboard tray according to the present invention.

Figure 5 is a perspective view showing the attachment of a cap on the upper peripheral edge edges 40 of the cardboard tray to form a completely sealed package according to the present invention.

Figure 6 is a perspective view illustrating a sealed tray obtained according to the manufacturing method and whose bottom has a deformation according to a groove arrangement according to the present invention.

Figures 7 to 9 are views showing a sealed tray obtained according to the manufacturing method and whose tabs comprises detachment means of the plastic film when the latter has a density greater than 1.

FIGS. 1 and 2 show a sheet of cardboard 1 of rectangular or square shape laid flat which is firstly cut in each of its angles A according to the same cutting profile 2 and secondly ribbed in its thickness. by means of first grooves called "lower grooves 6" and second grooves called "upper grooves" 7.

The cutouts 2 and the first and second grooves or ribs 6, 7 formed in the cardboard sheet 1 make it possible to form, on the one hand, tongues 4, 5 opposite in pairs and, on the other hand, a central portion 3 of the same rectangular shape. or square than that of the cardboard sheet 1.

The first ribs 6 arranged in the cardboard sheet 1 allow delimiting a first fold line between the central portion 3 and the tongues 4 and 5. Also the cardboard sheet 1 has parallel to the first ribs 6 of the second ribs 7 which are arranged in the upper part of the tongues 4, 5 making it possible to produce a second fold line delimiting for each tongue a peripheral edge 8. The cutout 2 formed in each corner A of the cardboard sheet 1 having for example with respect to a central axis of symmetry (a) a pencil-shaped profile.

When the cardboard sheet 1 has a rectangular shape, the central axis (a) of each cutout 2 is inclined firstly by an angle α with respect to the diagonal (d) of the cardboard sheet 1 passing through the center (o) of the latter and secondly an angle 13 with respect to the diagonal (d ') of the central portion 3 passing through the center (o) and the tip of the cutting 2 in the form of a peak pencil (Figure 2).

On the other hand, when the cardboard sheet 1 is of square shape, it is found that the central axis (a) of each cutout 2 made in the angles A of said sheet is carried by the diagonals (d, d ') passing through the center (o) of the cardboard sheet 1. 40 Each cutout 2 made in the angles A of the cardboard sheet 1 of rectangular or square shape consists of a first cut 20 whose opposite edges 21 are parallel to each other and parallel to the central axis (a) of said cutout 2, and a second cutout 22 having opposite edges 23 which are inclined and which extend those of the first cutout 20 towards the central portion 3.

The opposite edges 23 of each second cut 22 are inclined relative to the central axis (a) so as to meet at the crossing of the first fold line formed by the first ribs 6. The junction point of the edges opposed 23 of each cut 2 also forms on the one hand each corner of the central portion 3 and the tip of the pencil-shaped form of the corresponding cut 2. The opposite edges 21 of each first cut 20 are inclined at an angle θ which is close to 45 degrees with respect to a horizontal straight line (dh) which is carried by the second ribs 7.

The profile of the cuts 2 made in each corner A of the cardboard sheet 1 makes it possible, during the folding of said cardboard sheet 1, for the opposite edges 21, 23 of each cutout 20, 22 to come respectively against the other edges with edges. so that the peripheral edges 8 are continuous, flat and without relief or extra thicknesses The tabs 4 and 5 obtained after the making of the blanks 2 are respectively opposed in pairs so that said opposite tongues are identical in their dimensions and their profiles.

FIGS. 3 to 5 show a method of forming and producing a sealed container 10 from a cardboard sheet 1 on which a film 40 whose density can be smaller or greater than 1 is applied.

The cardboard sheet 1, whose profile is similar to that described previously, has angles A which are precut according to the profile of the blanks 2.

The cardboard sheet 1 is previously folded along the first and second ribs 6 and 7 so that the tongues 4 and 5 follow the internal profile of a mold 30 machined according to the profile of the tray 10 to obtain. The previously folded cardboard sheet 1 is then placed inside the mold 30.

The cardboard sheet 1 is held inside the mold 30 by means of retaining means provided on the upper edges of said mold and with which the peripheral edges 8 obtained after folding of the tongues 4 and 5 in the second ribs cooperate. 7.

As soon as the cardboard sheet 1 is held inside the mold 30, a film 40 is applied to all the inner faces constituting said sheet, which film may be made of plastic or any other material of which at least one faces is self-adhesive or in a thermoformable material or in a fusible material. The film 40 is disposed above the mold 30 and heated to its softening temperature to allow it to deform when the vacuum of the mold 30 is engaged by a strong depression. The edge-to-edge connections in the corners of the cardboard sheet 1 at the cutouts 20, 21 define slots which allow the passage of the vacuum to press the film 40 over the entire surface of the cardboard sheet 1.

During the evacuation of the mold 30 the film 40 is deformed and is pressed continuously against the central portion 3, the tongues 4 and 5 and the flat peripheral edge 8 of the cardboard sheet 1. The vacuum of the The mold 30 is then stopped and the cardboard sheet 1 in the form of a tray 10 is removed from said mold 30.

It can be seen that the film 40 enables the tabs 4 and 5 and the peripheral edges 8 to be interconnected in such a way as to maintain the cardboard sheet 1 according to the desired profile and to make a completely watertight container 10 even in the corners of the latter. It should also be noted that the film 40 makes it possible to join the opposite edges 21, 23 of each cutout 20, 22 between them, making it possible to achieve continuity of the sealing of the tongues 4 and 5 on the one hand in the corners of the tray 10 and on the other hand. on the other hand at the level of the peripheral edges 8. The tray 10 thus shaped comprises on the one hand a bottom formed by the central portion 3 of the cardboard sheet 1 and on the other hand vertical and inclined edges made by the tabs 4 and 5.

It will be noted that the peripheral edges 8 obtained by folding the tabs 4 and 5 are, at the corners of the tray 10, continuous and planar, that is to say without reliefs or overthicknesses and covered with the film 40.

Thus, the film 40 makes it possible to thermoform the tongues 4, 5 between them and to keep the tray 10 in shape throughout its service life.

The sealed container 10 thus obtained may cooperate with a lid 11 made of plastic or cardboard and which is applied and heat-welded to the flat peripheral edges 8 in order to close said container 10 and form a completely sealed package ensuring, for example packaging of food products.

Also the central portion 3 of the cardboard sheet 1 forming the bottom of the sealed tray 10 may be deformed to form suitable reliefs 9 40 for the recovery of exudates. When the central portion 3 has reliefs 9 these deniers are also covered, during the manufacture of the tray 10, the film 40 to make said tray 10 tight (Figure 6).

It will be noted that the cut-out 2 provided in each corner A of the cardboard sheet 1 may have a different profile than the one previously described without modifying or limiting the subject of the present invention. Indeed, the profile of the cutout 2 must allow after the assembly of the cardboard sheet 1 by means of the film 40 that the peripheral edge 8 thus obtained is in the corners of the continuous tray 10, without reliefs and extra thickness.

It is found that the sealed package thus obtained, that is to say consisting of the tray 10 and its lid 11 is completely recyclable.

Indeed when using a film 40 with a density of less than 1, the tray 10 is considered to be entirely made of cardboard and therefore recyclable. There is therefore no need to separate the film 40 from the cardboard sheet 1.

On the other hand, when the film 40 is of a density greater than 1, it is necessary for the user to be able to separate said film 40 from the tray 10 in order to be able to recycle the cardboard sheet 1 on one side and said film 40 of the other.

In this case, the tongues 4 and 5 comprise at the level of second ribs 7 cutouts 12 forming clips 13 which are wrapped during the shaping and forming process of the sealed tray 10 by the film 40 (FIGS. 7 to 9).

The application of the film 40 on the cardboard sheet 1 is obtained by the same method as that described above.

The withdrawal of the film 40 from the tray 10 is obtained when the user deforms the clips 13 formed in the cardboard sheet 1 towards the inside of said tray 10.

This deformation performed on the cardboard sheet 1 allows the user to pull on the film 40 to completely remove it from the tray 10 so as to then be able to recycle said cardboard sheet 1 in the sorting made via the die of the products in question. cardboard, while the film 40 is thrown into the trash can of garbage via incineration or another way of recycling.

As a variant, the clips 13 formed in the cardboard sheet 1 can also serve as a blocking element for a lid, not shown, for closing the tray 10.

It should further be understood that the foregoing description has been given by way of example only, and that it in no way limits the scope of the invention which would not be dispensed with by replacing the details of described by any other equivalent. 20

Claims (14)

REVENDICATIONS1. Watertight cardboard tray for recycling and for packaging products, characterized in that it consists on the one hand of a cardboard sheet (1) having in its corners cutouts (2) for determining tongues (4, 5) each connected to a central portion (3) via a first folding rib (6), while said tongues (4, 5) comprise a second folding rib (7) allowing determining on each of said tabs (4, 5) a peripheral edge (8), and secondly a film (40) applied to the inner face of said cardboard sheet (1) for connecting and holding sealing the profile of said tray (10) the central portion (3), the tabs (4, 5), the cutouts (2) and the peripheral edges (8) so that said peripheral edges (8) are continuous, planes and without reliefs or overthickness. 2. Watertight cardboard tray according to claim 1, characterized in that the cutout (2) formed in each corner A of the cardboard sheet 1 has, with respect to a central axis of symmetry (a), a profile in the form of pencil. 3. Waterproof cardboard tray according to claim 2, characterized in that each cut (2) made in the angles A of the cardboard sheet (1) consists of a first cut (20) whose opposite edges (21). are parallel to each other and parallel to the central axis (a) of said blank (2), and a second blank (22) having opposite edges (23) which are inclined and extend those of the first blank (20); ) towards the central part (3). Watertight cardboard tray according to claim 2, characterized in that when the cardboard sheet (1) has a rectangular shape, the central axis (a) of each blank (2) is inclined on the one hand by a angle a with respect to the diagonal (d) of the cardboard sheet (1) passing through the center (o) of the latter and secondly from an angle (3 with respect to the diagonal (d ') of the central portion (3) passing through the center (o) and the tip of the cut (2) shaped pencil tip. 5. Waterproof cardboard tray according to claim 2, characterized in that when the cardboard sheet (1) is square, the central axis (a) of each cutout (2) made in the angles A is carried by the diagonals (d, d ') passing through the center (o) of said cardboard sheet (1). 6. waterproof tray cardboard according to claim 3, characterized in that the opposite edges (21) of each first blank (20) are inclined at an angle S2 which is close to 45 degrees relative to a horizontal line (dh) . Watertight cardboard tray according to Claim 3, characterized in that the profile of the cut-outs (2) formed in each corner A of the cardboard sheet (1) makes it possible, when the latter is folded, to follow the first and second ribs (6). 7) that the opposite edges (21, 23) of each cutout (20, 22) are respectively opposite to the other edge edges so that the peripheral edges (8) are continuous, planar and without relief or overthickness. Watertight cardboard tray according to claim 1, characterized in that the central part (3) of the cardboard sheet (1) can be deformed to form reliefs (9). 9. Waterproof cardboard tray according to claim 1, characterized in that the film (40) is made of a plastic material with a density greater than or less than 1. Watertight cardboard tray according to Claim 1, characterized in that the tabs (4, 5) comprise at the second ribs (7) cutouts (12) forming clips (13) which are wrapped by the film (40). ) to seal said cutouts. 11.Bacon waterproof cardboard according to claim 1, characterized in that the plane peripheral edges (8) cooperate with a lid (11) of plastic material or cardboard sealing the said tray (10) for packaging products . 12. A method of manufacturing a tray (10) of waterproof cardboard by means of a cardboard sheet (1) according to any one of claims 1 to 11, characterized in that it consists: - To take a sheet cardboard (1) having folding ribs (6, 7) and in the corners A cutouts (2) for determining a central portion (3), tabs (4, 5) and peripheral edges (8), - To arrange the pre-folded cardboard sheet (1) inside a mold (30) to the profile of the tray (10) to be obtained, - to apply a film (40) to the cardboard sheet (1) enabling the central part (3), tabs (4, 5), cut-outs (2) and peripheral edges (8) to be assembled and sealed together, - to remove the tray (10) of the mold (30). 13. A method of manufacturing a tray (10) of waterproof cardboard by means of a cardboard sheet (1) according to claim 12, characterized in that it consists in heating the film (40) to its temperature softening to allow it to deform when vacuuming the mold (30) .45 A method of manufacturing a carton (10) of waterproof cardboard by means of a cardboard sheet (1) according to claim 13, characterized in that the evacuation is obtained via the edge-to-edge fittings. provided at the cutouts (20, 21) which allow the passage of the vacuum to press the film (40) over the entire surface of the cardboard sheet (1).