FOOD POT

Abstract

Food container (61) comprising: a one-piece body (62, 64, 66, 68) made of a liquid- and gas-tight plastic material, the body (62, 64, 66, 68) comprising: a collar (62) with a thickness (e) of less than 0.25 mm; and a side wall (66) and a base (68) forming a cavity (64) suitable for containing a liquid or semi-liquid product, the base (68) having a thickness (e2) between 0.05 and 0.1 mm and the side wall (66) having a thickness (e1) of less than 0.06 mm; and a paper sleeve (50) surrounding the side wall (66) and disposed in contact with the collar (62), the paper constituting the sleeve (50) having a basis weight equal to or greater than 110 g / m². Figure 2

Description

Title of the invention: FOOD POT Technical field

[0001] The present disclosure relates to the field of food containers and their manufacture and in particular food pots which can contain liquid or semi-liquid products such as yogurt, milk, or equivalent. Prior art

[0002] The manufacturing process generally used to manufacture food pots consists of shaping a sheet of plastic material (polystyrene) by a thermoforming process to form several dozen pots. A banner presenting the relevant commercial and regulatory information is stuck on the side wall of each pot. After thermoforming, the pots are filled and sealed with a film. Finally, the pots are cut to obtain a group of pots in the desired number, ready for packaging.

[0003] The technology used is sometimes known by the acronym FFS (for "Form-Fill-Seal"). Sheets with an average thickness of 0.80 mm are used for this type of application. Indeed, food jars must demonstrate a certain mechanical strength so that they are not damaged during handling (stacking, packaging, transport, holding by the user, etc.) and so that the integrity of their contents is guaranteed.

[0004] Recent regulations and environmental awareness are encouraging people to gradually abandon plastic. Examples include the "anti-waste law for a circular economy" in France, and Directive 94 / 62 / EC, known as PPWD (for "Packaging and Packaging Waste Direct" in English).

[0005] The authorities thus wish to encourage the use of alternative solutions to plastic, such as packaging made from natural materials or bulk sales in multi-use containers. However, none of these alternatives are suitable for liquid or semi-liquid food products, for obvious reasons relating to health safety or the potential presence of allergens.

[0006] In the absence of being able to completely eliminate plastic, using recyclable plastics seems to be preferable. However, PET (polyethylene terephthalate), which has the advantage of being recyclable, cannot immediately constitute an alternative to polystyrene for the manufacture of pots: in fact, the pot manufacturing process involves a bending rupture step (in particular when the user separates a pot from the group of pots) and PET has an in- compatible with this use.

[0007] Unable to use recyclable plastic with the same design as current pots, the applicant attempted to reduce the quantity of plastic. However, limiting the quantity of plastic is a priori opposed to the constraints of mechanical strength and health safety that these pots require. Indeed, a food pot must be able to withstand compression at 150 N and it is obvious that reducing the quantity of plastic (i.e., the thickness of the thermoformed sheet) implies a reduction in the mechanical strength of the pot. Also, holding it in the hand is not pleasant for the consumer if the pot twists or compresses on itself with simple pressure from the fingers. It has also been observed that thinning the plastic sheet gives rise to manufacturing problems since weaknesses appear in the angular areas and in particular at the junction between the upper collar of the pot and the side wall of the pot.

[0008] There is therefore a need for a food jar design that is in line with environmental guidelines but can also overcome the disadvantages mentioned above resulting from the reduction in the amount of plastic. Summary

[0009] The present disclosure meets this need.

[0010] A food pot is provided comprising: a single-piece body made of a liquid- and gas-tight plastic material, the body comprising: a collar with a thickness of less than 0.30 mm; and a side wall and a base forming a cavity capable of containing a liquid or semi-liquid product, the base having a thickness of between 0.05 and 0.2 mm and the side wall having a thickness of less than 0.06 mm; and a paper sleeve surrounding the side wall and arranged in contact with the collar, the paper constituting the sleeve having a weight equal to or greater than 110 gr / m2.

[0011] While reducing the thickness of the plastic sheet is counterintuitive (see discussion above), the inventors were able to demonstrate that the mechanical strength function could be separated from the sealing function required for a food jar. The plastic makes it possible to provide the function of a leak-proof container while having a thickness 5 times thinner than existing jars. A paper sleeve with a weight of at least 110 gr / m2 is of sufficient thickness to provide most of the mechanical strength of the jar. Compressive strength (vertical for stacking or transverse for handling) is thus preserved despite the reduction in the thickness of the plastic. Lowering the thickness of the plastic allows the paper strip to be in contact with the collar: the paper is strong enough to resist corner deformations that would occur just below the collar.The paper weight can be less than 250 gr / m2. Beyond this value, the gain in mechanical resistance is no longer relevant in view of the stresses of . compression (stacking of products or holding in the hand) and too heavy paper would therefore unnecessarily weigh down the pot and complicate its shaping in the mold.

[0012] It is understood that in the present application, the term “paper” encompasses any type of paper (recycled, coated, cardboard, matte, glossy, laminated, varnished, with mineral fibers, etc.) as well as any type of cardboard (corrugated or not, rigid, honeycomb, etc.). The paper can be monochrome or be printed, in particular with regulatory and / or commercial information.

[0013] The plastic material is liquid and gas tight. Thus, the body of the pot is free of holes. Once the pot is sealed with a lid, the internal cavity of the pot is isolated from the external environment.

[0014] The thicknesses of the base of the pot and of the side wall are much less than the thickness of the sheet (which is substantially that of the collar). The thickness ranges are synonymous with a stretching coefficient of between 3 and 7. Optionally, the stretching coefficient of the invention is between 6.0 and 7.0. The stretching coefficient is defined by a ratio between the surface area generated by the thermoforming (sum of the surface area of ​​the base and the side wall) and the corresponding initial surface area of ​​the sheet (the hollowed-out surface delimited by the inner edge of the collar).

[0015] According to another aspect, the paper constituting the sleeve represents at least 50%, or even at least 70% of the total mass of the pot. This ratio opens the field to other recycling techniques, available only when one of the materials constituting the pot weighs at least 70% of the total mass of the pot.

[0016] According to another aspect, the paper constituting the sleeve has a grammage greater than 160 gr / m2.

[0017] According to another aspect, the paper constituting the sleeve has a grammage of between 160 and 200 gr / m2. These ranges of values ​​are an ideal compromise: the sleeve is on the one hand sufficiently strong to ensure the mechanical strength of the pot and has sufficient weight to guarantee the recyclability of the pot; and the sleeve is on the other hand sufficiently light to be easily shaped and not to add unnecessary weight to the assembly (which would result in increased CO2 production due to its transport).

[0018] According to another aspect, the sleeve extends from the collar to a distance from the base of less than 1.20 mm. Thus, unlike existing banners which must be kept away from the collar and away from the base of the pot (3-4 mm minimum) so that the banner is not damaged by a fault in positioning the banner or by deformations of the plastic, the paper sleeve can extend over the entire height or almost the entire height of the pot. In addition to the more aesthetic visual appearance, this structure guarantees mechanical strength in vertical or horizontal compression. transverse.

[0019] According to another aspect, the sleeve is bonded to the side wall by a hot melt adhesive. It is thus possible to bond the sleeve to the wall during thermoforming, by heating the plastic sheet, and / or by heating the mold.

[0020] The invention also relates to a method for manufacturing a food pot comprising the following steps: providing a mold having a recess opening onto a bearing surface; inserting a paper band arranged in a sleeve into the recess flush with the bearing surface; arranging a plastic sheet with a thickness of less than 0.30 mm on the bearing surface; plastically deforming the sheet so as to form a base with a thickness of between 0.05 and 0.2 mm and a side wall with a thickness of less than 0.06 mm, the paper sleeve surrounding the side wall; and cutting the sheet to form a collar, the paper constituting the sleeve (50) having a weight of between 110 and 250 gr / m2.

[0021] This process aims to obtain the pot described above whose hygienic and ecological properties conform to the expectations discussed above.

[0022] According to another aspect, the sheet has a thickness of between 0.15 and 0.19 mm.

[0023] According to another aspect, the paper constituting the sleeve represents at least 50%, or at least 70% of the total mass of the sleeve, collar, side wall and base.

[0024] According to another aspect, the paper constituting the sleeve has a weight of between 160 and 200 gr / m2.

[0025] According to another aspect, at least a portion of an internal surface of the banner is coated with a layer of glue. During the plastic deformation step, the mold is maintained at a temperature between 40 and 85°C. This technique makes it possible to melt the glue inside the banner by heating the mold rather than by heating the plastic, the thickness of which may no longer be compatible with the heating. Also, heating the mold for successive pot forming cycles is generally less energy-intensive than heating each sheet of plastic.

[0026] According to another aspect, the method further comprises a step of depositing glue on an internal surface of the sleeve prior to plastic deformation. If the usual banners are multi-layer strips of which one layer is a hot-melt glue, the technique of depositing glue on the sleeve constitutes an interesting alternative since by depositing the glue on the internal surface of the sleeve, there is plenty of time to choose a pattern (dots, lines, etc.) and its location, in order to obtain a precise level of adhesion. It may indeed be advantageous to provide that the sleeve is easily detached from the pot after use, for example if it is desired to mechanically separate the paper from the plastic.

[0027] According to another aspect, the step of plastic deformation of the sheet is carried out using a punch penetrating into the sleeve, and the recess has a bottom and the punch has a section describing a homothety of the bottom, the homothety ratio being between 75% and 98%. The low thickness of plastic material makes it possible to envisage a punch of larger dimensions than usual, allowing better dimensional control of the pot and lower stress concentrations for the same rate of deformation of the plastic. Brief description of the drawings

[0028] Other characteristics, details and advantages will appear on reading the detailed description below, and on analyzing the attached drawings, in which:

[0029] [Fig. 1] shows a usual method of manufacturing a food jar.

[0030] [Fig.2] shows a method of manufacturing a food jar according to the present disclosure.

[0031] [Fig.3] shows in detail a food jar obtained by the process illustrated in [Fig.2]. Description of the embodiments

[0032] [Fig.l] summarizes very schematically the three main stages (a, b, c) of the manufacture of a known food pot.

[0033] In a first step (a), a sheet 1 of plastic material is placed on a mold 2, the sheet 1 resting on a support surface 3 of the mold 2. The sheet 1 is generally made of polystyrene and has a thickness E of between 0.80 and 1.20 mm.

[0034] The mold 2 has a series of recesses 4, only one of which is visible in [Fig.l]. The recess 4 is delimited by a lateral surface 6 and a bottom 8. The example illustrated shows a recess with an inclined side wall. The general shape of the recess 4 may be truncated or of square section.

[0035] A thermoforming step (b) is then carried out, by applying a vertical force using a punch 10. The sheet 1 is thus deformed to match the shape of the mold 2. The punch 10 moves to a given position, for example a position in which the sheet 11 comes into contact with the bottom 8 of the recess 4.

[0036] After thermoforming (b), the deformed sheet 11 is filled with the liquid or semi-liquid product, cut and closed to obtain a pot 21 as shown in [Fig.l] (c). The pot 21 comprises a collar 22 on which a cover 23 is sealed. An internal cavity 24 containing the liquid or semi-liquid product is delimited by a side wall 26 and a bottom 28. The collar 22 and the bottom 28 have a thickness E substantially equivalent to that of the sheet 1, the side wall 26 having a lesser thickness due to its stretching.

[0037] A banner 30 may be glued by an adhesive layer 32 around the ex face of the side wall 26. Such a banner usually has a weight of between 80 gr / m2 and 95 gr / m2. The banner 30 does not extend over the entire height of the pot: it is arranged a few millimeters (3-4) away from the collar 22 as well as a few millimeters away from the bottom 28. It is not possible to arrange the banner 30 in contact with the collar 22 because the latter would deform and be damaged when closing the pot or during transport.

[0038] [Fig.2] schematically illustrates a method according to the present invention.

[0039] A mold 42 is provided with a bearing surface 43 onto which a series of recesses, one of which 44 is visible in [Fig.2] (a). The recess 44 is delimited by a lateral surface 46 and a bottom 48.

[0040] A paper banner 50, i.e. a sheet longer than it is wide, is arranged in the recess 44 of the mold 42 so as to form a sleeve 50, i.e. a substantially axisymmetrical shape around a vertical axis of the recess 44. The sleeve 50 may be arranged flush with the bearing surface 43, in order to ensure that after thermoforming, the sleeve 50 is in contact with the collar of the pot (see [Fig.2](c)). This flushness is naturally obtained by the width of the banner forming the sleeve 50 which equals the dimension of the side wall 46. When the sleeve 50 is smaller than the side wall 46, a projection (not shown) may be provided on the bottom 48 of the recess 44.

[0041] The sleeve 50 may be made of any type of paper and may have a weight greater than 110 gr / m2 and in particular between 110 and 250 gr / m2. Optionally, this weight is between 160 and 200 gr / m2, or even between 190 and 195 gr / m2. It may be made of corrugated cardboard. The sleeve may have indications on its outer surface concerning regulatory or commercial indications relating to the product contained in the pot. The sleeve 50 may be partially hollowed out or perforated or contain transparent portions. In addition or as an alternative, the sleeve 50 may comprise internal (e.g. fibers) or external (e.g. ribs) reinforcements.

[0042] The sleeve 50 may extend over the entire lateral surface 46 (over 360° around a vertical axis). Alternatively, the sleeve 50 may extend only partially over the lateral surface 46. In this case, the recess 44 may comprise an angular indexing (for example an excess thickness on the lateral surface 46) to position the sleeve 50 according to a given angular position.

[0043] After the sleeve 50 has been put in place, a plastic sheet 41 is placed on the bearing surface 43 of the mold 42. The sheet 41 has a thickness e of less than 0.25 mm, for example between 0.05 and 0.20 mm, and in particular between 0.15 and 0.19 mm. The sheet 41 may, for example, be made of polyethylene terephthalate (PET) or polypropylene (PP). It was particularly surprising to note that PET, traditionally Although not necessarily suitable for hand breaking, these thickness levels are nevertheless compatible with the clean breaks expected by the user of food jars. Polystyrene (PS) also remains usable.

[0044] A given quantity of hot melt glue 49 may be placed on the inner surface of the sleeve 50. This glue may be applied to the paper in a given pattern or may consist of a homogeneous layer forming an integral part of the sleeve 50.

[0045] The thermoforming step (b) may consist of applying a vertical force to the sheet 41 to deform it into a deformed sheet 51 using a punch 60. The punch 60 penetrates into the recess 44 of the mold and therefore into the sleeve 50. The punch forces the sheet 51 to be deformed and to take on the internal shape of the sleeve 50.

[0046] The punch 60 may have a cylindrical or partially conical shape. Alternatively, the punch 60 may be fluted or may have various patterns, including patterns corresponding to undulations provided in the paper forming the sleeve 60.

[0047] The dimension of the punch 60 (its diameter or the width of its section if it is not a metric y-axis shape) can be between 75% and 98% of the dimension of the base 68. Given the potential elasticity of the sleeve 50, the punch can even be larger than the dimension of the base 68, in order to maximize the precision of the operation. Also, the local mechanical stresses undergone by the plastic can be less.

[0048] As an alternative to using a punch, other techniques can be used to deform the sheet so that it fits the shape of the mold. For example, localized heating (particularly by LED) can make part of the sheet malleable to the point that it “flows” into the mold.

[0049] Thus, the presence of a punch is not essential to carrying out the method of the invention.

[0050] During thermoforming, the glue 49, solid when cold, is heated to become malleable and adhere to the side wall (66 in [Fig.2](c)). The temperature rise of the glue 49 can be obtained by conduction via the temperature of the sheet 51.

[0051] However, since the sheet 51 is thinner than in a standard process, the amount of heat stored in the sheet 51 can dissipate quickly. Under these circumstances, in order to ensure the malleability of the glue 49, the mold 42 can be heated and maintained at temperature, for example at a temperature between 40°C and 80°C. Preferably, the glue 49 is chosen to be malleable when the temperature of the mold is between 45°C and 60°C, i.e. a temperature suf extremely low to limit the energy required for the operation without risking the 49 glue melting at summer ambient temperatures.

[0052] After the thermoforming step (b), the cavities of the sheet 51 are filled with a food product, a film closes the cavities and the sheet 51 is cut according to the number of pots desired for packaging.

[0053] [Fig.2] (c) shows an individual pot 61, after its separation from the pack of pots. The pot 61 has a collar 62 on which is sealed a lid 63. An interior cavity 64 is filled with a liquid or semi-liquid (yogurt, milk, or equivalent). The cavity 64 is delimited by a side wall 66 and a base 68. The collar 62, the side wall 66 and the base 68 together form the one-piece body of the pot 61 made of thermoformed plastic. Around the side wall 66, the sleeve 50 of paper is glued by the glue 49. The glue can be chosen so that the sleeve 50 can be detachable from the plastic, or even "peelable" or "peelable". Such an option makes it possible to recycle the body of the plastic pot on one side and the paper of the sleeve on the other side.

[0054] Depending on the relative dimension of the sleeve 50 with respect to the mold 42, the sleeve 50 may extend all around the side wall 66 of the pot 61 (over 360° around a vertical axis). Alternatively, the sleeve 50 may extend only partially around the wall 66, for example over an area representing at least 70 to 90% of the perimeter of the section of the pot 61.

[0055] The pot thus obtained retains the mechanical and sanitary properties compatible with food use and vertical stacking of several pots. Due to the low thickness of the sheet 41 and the side wall 66, the pot obtained has a plastic mass five times lower than a standard pot of the same capacity. The total mass of the pot of the present disclosure (excluding its food content) is approximately half that of a standard pot.

[0056] At least 50% and preferably 70% of the total mass consists of the paper of the sleeve 50.

[0057] [Fig. 3] identifies certain characteristics of the pot 61. The collar has a thickness e which corresponds substantially to the thickness of the sheet 41 / 51, that is to say a thickness less than 0.30 mm and more particularly between 0.15 and 0.19 mm. The side wall 66 has a thickness el less than 0.06 mm or less than 0.05 mm or less than 0.04 mm. The base 68 has a thickness e2 between 0.05 and 0.2 mm.

[0058] The densest plastic part is the collar 62: approximately 30 to 40% of the total mass of plastic is contained in the collar 62.

[0059] The sleeve 50 is in contact with the collar 62 and extends over a very large part of the pot in height. The distance indicated as D in [Fig.3] between the bottom of the sleeve 50 and the lower surface of the base 68 is between 0 and 1.20 mm. This distance is for example 0.8 mm. This distance can be controlled by providing a projection on the bottom of the mold 42, on which the sleeve 50 can be placed before the thermoforming operation.

[0060] Although the contact between the sleeve 50 and the collar 62 can generate a turtleneck effect for a usual banner, in the present case, the thickness ratios between plastic and paper are such that deformation of the paper by the plastic is made improbable.

[0061] The thickness of the paper, denoted e3, may be between 0.6 and 2 mm, optionally between 0.9 mm and 1.8 mm, or between 1 mm and 1.8 mm. The resistance to vertical compression of the paper (i.e. transversely to a strip of paper intended to form the sleeve), considered alone, may be greater than 30 daN. The thickness e3 is constant all around the pot. The strip of paper may be perfectly aligned side to side, or have an end overlap. In one embodiment, the strip of paper is free of holes.

[0062] The pot thus obtained offers good handling and good vertical compression strength (RCV) when stacked. The sleeve 50 compensates for, or even exceeds, the losses in mechanical strength induced by the reduction in plastic thickness.

[0063] It should be noted that [Fig. 3] illustrates a pot of generally conical shape but the invention is not limited to this shape of pot. The same teachings can in fact be applied to pots of different sections and form factors, in particular of square, cylindrical or polyhedral shape. The invention however advantageously targets pots formed with a stretching coefficient of between 3 and 7. The stretching coefficient is defined by a ratio between the surface generated by thermoforming (sum of the surface of the base and the side wall) and the corresponding initial surface of the sheet (the hollowed surface delimited by the inner edge of the collar).

[0064] In a variant, the plastic body of the pot 61 and / or the lid 63 is / are perforated to further reduce the mass of the pot. This variant is conceivable when the pot 61 is intended to contain non-liquid products.

[0065] The invention has been described in the context of a pot intended as a food container for liquids or semi-liquids, but other applications are possible, in particular for containing other everyday products (coffee, cereals, detergents, cosmetic or (para)pharmaceutical products, etc.). Also, the invention is not limited to specific shapes or dimensions and may also be applied to containers of all sizes, in particular with a height or width of between 1 cm and several tens of centimeters. List of reference signs

[0066] 1: Standard sheet before formatting 2: mold 3: support surface 4: recess 6: side wall 8: background 10: punch 11: formatted sheet 21: pot 22: collar 23: operculum 24: cavity 26: side wall 28: base 30: banner 32: glue 41: Standard sheet before formatting 42: mold 43: support surface 44: recess 46: side wall 48: background 49: glue 50: sleeve 51: formatted sheet 60: punch 61: pot 62: collar 63: operculum 64: cavity 66: side wall 68: base E: standard sheet thickness e: thickness of the sheet and the collar el: thickness of the side wall e2: base thickness e3: sleeve thickness

Claims

Claims

1. Food pot (61) comprising: a. a body (62, 64, 66, 68) in one piece made of a liquid- and gas-tight plastic material, the body (62, 64, 66, 68) comprising: i. a collar (62) with a thickness (e) of less than 0.30 mm; and ii. a side wall (66) and a base (68) forming a cavity (64) capable of containing a liquid or semi-liquid product, the base (68) having a thickness (e2) of between 0.05 and 0.2 mm and the side wall (66) having a thickness (el) of less than 0.06 mm; and b. a paper sleeve (50) surrounding the side wall (66) and arranged in contact with the collar (62), the paper constituting the sleeve (50) having a weight equal to or greater than 110 gr / m2.

2. Pot (61) according to claim 1, in which the paper constituting the sleeve (50) represents at least 50%, or even at least 70% of the total mass of the pot (61).

3. Pot (61) according to one of the preceding claims, in which the paper constituting the sleeve (50) has a weight of between 160 and 200 gr / m2.

4. Pot (61) according to one of the preceding claims, in which the sleeve (50) extends from the collar (62) to a distance from the base (68) of less than 1.20 mm.

5. Pot (61) according to one of the preceding claims, in which the sleeve (50) is glued to the side wall (66) by a hot melt glue (49).

6. A method of manufacturing a food pot (61) comprising the following steps: a. providing a mold (42) having a recess (44) opening onto a bearing surface (43); b. inserting a paper band arranged in a sleeve (50) into the recess (44) flush with the bearing surface (23); c. placing a sheet (41) of plastic with a thickness (e) of less than 0.30 mm on the support surface (23); d. plastically deforming the sheet (41, 51) so as to form a base (68) with a thickness (e2) of between 0.05 and 0.2 mm and a side wall (66) with a thickness (el) of less than 0.06 mm, the sleeve (50) of paper surrounding the side wall (66); and e. cutting the sheet (51) to form a collar (62), the paper constituting the sleeve (50) having a grammage equal to or greater than 110 gr / m2.

7. The method of claim 6, wherein the paper constituting the sleeve (50) represents at least 50%, or even at least 70% of the total mass of the sleeve (50), the collar (62), the side wall (66) and the base (68).

8. Method according to one of claims 6 or 7, in which the paper constituting the sleeve (50) has a weight of between 160 and 200 gr / m2.

9. Method according to one of claims 6 to 8, in which at least part of an internal surface of the banner is coated with a layer of glue (49), and in which during the plastic deformation step, the mold (42) is maintained at a temperature between 40 and 85°C.

10. Method according to one of claims 6 to 9, further comprising a step of depositing glue (49) on an internal surface of the sleeve (50) prior to plastic deformation.

11. Method according to one of claims 6 to 10, in which the step of plastic deformation of the sheet (41, 51) is carried out using a punch (60) penetrating into the sleeve (50), and in which the recess (44) has a bottom (48) and the punch (50) has a section describing a homothety of the bottom (48), the homothety ratio being between 75% and 98%.

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