Capsule intended to contain a substance for preparing a beverage

Abstract

The invention relates to a capsule (1) comprising a body (1a) that has a side wall (2) bordered on either side, respectively, by a bottom and a rim (4) that surrounds an opening (5) in the body, the rim having a lower wall (4b) that projects laterally, to which a ring (10) is fitted that has a free lower face (10b) provided with a bearing surface (11), the body being formed from cellulose and the ring (10) being made from a polymer material that is compostable according to standard EN 13432 and being more rigid than the body (1a), the ring having at least one sealing lip (12) that projects in an axial direction from the bearing surface (11) of the free lower face (10a) of the ring.

Description

[0001] intended to contain a substance

[0002]

[0003] of a drink

[0004] The invention relates to a capsule intended to contain a substance for the preparation of a beverage.

[0005] Capsules are known whose body has a side wall bordered on both sides by respectively a bottom and a rim surrounding an opening of said body, said body defining a compartment for packaging a substance for the preparation of a drink, which is introduced into said compartment, for example through said opening, then enclosed inside said compartment, for example by association, in particular by gluing, of a lid on the rim to cover the opening.

[0006] Such capsules are primarily intended for preparing hot beverages such as coffee, tea, or infusions. To do this, a capsule is placed in a designated compartment of a machine, where it is held in place by a piston while an extraction liquid, such as hot water, is passed through it and the substance it contains. The capsule is then expelled from the machine by gravity after the piston is removed.

[0007] The capsule must be opened to allow the drink to flow through it, but the substance must be kept in the capsule with good barrier properties against oxygen and air moisture in order to preserve its organoleptic properties.

[0008] To achieve this, capsules are known whose body is formed by stamping a sheet of metallic material, particularly aluminum. Such capsules offer good airtight and moisture-proof properties, but are expensive to produce and difficult to recycle.

[0009] We also know, for example from documents WO-2024 / 028247 and WO-2024 / 28248, of capsules whose body is formed by molding a cellulose pulp, the side wall of said body being covered with a coating and / or a sealing label.

[0010] These capsules have an improved ecological impact, in that they are biodegradable and compostable, both industrially and domestically, and also guarantee good organoleptic preservation of the substance they contain.

[0011] However, a cellulose capsule has the disadvantage of not being inert with respect to water, particularly under the combined effect of the temperature and pressure to which it is subjected during the preparation of the drink.

[0012] Thus, after use, swelling and / or softening of the capsule may be observed, which may hinder its expulsion by gravity, particularly due to poor interference between the machine and the edge of said capsule.

[0013] To overcome these drawbacks, document FR-2989258 describes a capsule whose cardboard-based body is equipped with a ring which is attached to a lower wall of its annular rim, said ring being made of a heat-sealable material whose rigidity allows said rim to be reinforced.

[0014] However, this solution is not satisfactory, as the rigidity of the added ring does not allow it to ensure sufficient sealing at the interface between the annular rim and the piston of the machine.

[0015] Document WO-2015 / 082982 also describes a capsule equipped with a sealing ring whose material would become relatively rigid after use to facilitate its expulsion. However, this hypothetical behavior does not guarantee sufficient rigidity to ensure reliable capsule expulsion.

[0016] The invention aims to improve the prior art by proposing in particular a cellulose capsule whose annular rim is reinforced in order to guarantee its hold throughout the preparation of a beverage, and this while guaranteeing the sealing at the level of said rim during said preparation.

[0017] To this end, the invention proposes a capsule intended to contain a substance for the preparation of a beverage by placing said capsule in the housing of a piston, said capsule comprising a body defining a compartment for the packaging of a substance for the preparation of the beverage, said body having a lateral wall bordered on either side respectively by a bottom and a rim surrounding an opening of said body, said rim having a lower wall projecting laterally from said lateral wall, said capsule being equipped with a ring which is attached to said lower wall having an upper face bearing on said lower wall and a free lower face having a bearing surface on which the piston is intended to bear,said body being made from cellulose and the ring being made from compostable polymer material according to standard EN 13432, exhibiting a rigidity which is greater than that of the cellulose-based body, said ring having at least one sealing lip which is formed in a projecting axial direction from the bearing surface of the free lower face of said ring.

[0018] Other features and advantages of the invention will become apparent in the following description, made with reference to the accompanying figures, in which:

[0019] - Figure 1 represents an axial section of a capsule according to an embodiment of the invention, Figure 1a representing, in partial perspective, an enlargement of Figure 1 centered on the association of the ring with the annular rim of the body of the capsule;

[0020] - Figure 2 represents the capsule of the previous figures, in partial axial section along another cutting plane, and centered on one side of the annular rim;

[0021] - Figure 3 represents, in partial axial and lateral section, and along another cutting plane, a stack of two rings as shown in the previous figures; - Figures 4 and 5 represent, following a view similar to Figure 2, a capsule according respectively to a variant embodiment of the previous figures;

[0022] - Figure 6 represents, in partial axial section centered on one side of the annular rim, a stacking of two capsules according to a variant of the embodiment of the previous figures.

[0023] In relation to these figures, a capsule 1 intended to contain a substance for the preparation of a drink is described below.

[0024] The capsule 1 comprises a body 1a having a lateral wall 2 bordered on both sides by a bottom 3 and by a rim 4 surrounding an opening 5 of said body.

[0025] Body 1a is formed from cellulose, in particular by molding a cellulose pulp, and preferably contains exclusively cellulose, in particular 100% from sustainable and / or organic farming.

[0026] Thus, it is possible to manufacture a capsule 1 that is easily recyclable in a low cost and with high yield, with reduced carbon dioxide emissions, especially compared to injection molding of a plastic material.

[0027] Furthermore, the exclusive use of cellulose allows for the production of a capsule 1 whose body 1a can be easily composted, both industrially and domestically, notably with a reduced composting time (approximately one month) compared to the average composting time of capsules made from molded compostable plastic (approximately six months). Specifically, capsule 1 is biodegradable and / or compostable according to standard EN 13432.

[0028] According to one embodiment, the process may involve forming the body 1a of the capsule 1 by wet molding, i.e. by preparing a paste comprising cellulose pulp suspended in water, the body 1a of the capsule 1 being formed with said paste before it dries.

[0029] According to another embodiment, the body 1a of capsule 1 is formed by dry molding of a sheet of cellulose pulp, which makes it possible to considerably increase the manufacturing yield of the capsule, while limiting the number, size and cost of the necessary facilities, as well as the costs in water and energy.

[0030] In particular, the dry molding manufacture of the body 1a of the capsule 1 involves forming a sheet of cellulose pulp, then thermoforming the body 1a of the capsule 1 by hot molding of said sheet.

[0031] According to another embodiment of dry molding the body 1a of capsule 1, the sheet is to be formed as a cellulose pulp sheet, having a thickness of between 0.5 and 1 mm, for example, approximately 0.75 mm. In particular, the sheet can be made from NBSK (Northern Bleached Softwood Kraft) type cellulose pulp.

[0032] Advantageously, the sheet can be moistened, for example by spraying water on the surface, before thermoforming, in order to improve its molding capacity while allowing the water to evaporate during thermoforming.

[0033] Advantageously, the process involves molding the body 1a from a cellulose pulp comprising microfibrillated cellulose (MFC, for Micro-Fibrillated Cellulose), in particular between 1% and 50% by weight of microfibrillated cellulose MFC.

[0034] Microfibrillated cellulose (MFC) consists of individual cellulose microfibrils or aggregates. These microfibrils typically have a diameter of 2 to 20 nanometers and a length on the order of a few micrometers. Microfibril aggregates are composed of several cellulose microfibrils agglomerated together.

[0035] In relation to the figures, the body 1a of the capsule 1 has a geometry of revolution around a central axis A forming a lateral wall 2 which is generally inscribed in a truncated cone with a right generatrix between the bottom 3 and the upper rim 4. In an alternative not shown, the lateral wall 2 may have a substantially cylindrical geometry of revolution.

[0036] In the description, terms relating to positioning in space are used with reference to capsule 1 as shown in the figures, and in particular with respect to its axis A of revolution defined above. Specifically:

[0037] - the terms "superior" and "inferior" refer to positions located respectively at the bottom and top of figures 1, 2, 4, 5 and 6 (and respectively at the top and bottom of figure 3);

[0038] - the terms "axial" and "radial" refer to directions respectively along this axis A and away from or towards it; - the terms "inside" and "outside" refer to positions respectively near and far from this axis A.

[0039] Body 1a defines a compartment 6 for packaging a substance for the preparation of a beverage, the capsule 1 being equipped with a top lid (not shown) which is associated with the rim 4 to cover the opening 5, and thus close access to said compartment by said opening.

[0040] In particular, the rim 4 has an upper wall 4a which is laterally projecting from the lateral wall 2, notably by being radially aligned with the opening 5, the upper operculum being associated with the capsule 1 by sealing on said upper wall.

[0041] According to one embodiment, the opening 5 allows the substance to be loaded into the compartment 6, which is closed at the opposite end by the bottom 3. This opening is then closed by the upper lid after loading. In Figure 1, the bottom 3 has a lower passage 7 intended to be closed by means of a lower lid (not shown), in particular by peripheral sealing on a conical rim 3a of the bottom that surrounds the lower passage. This sealing can be carried out on a face 8 of the conical rim 3a located inside the compartment 6, or on a face 9 of the rim located outside the compartment.

[0042] In particular, the lower passage 7 can be first covered by the lower cover, in order to load the substance into the compartment through the upper opening 5, which is then closed by the upper cover.

[0043] Alternatively, capsule 1 can be loaded from the bottom 3. In this case, the upper opening 5 is first covered by the upper lid, then capsule 1 is turned over so that the substance can be loaded through the lower passage 7, the lower lid then being associated with said capsule to close said compartment before the preparation of the drink.

[0044] In order to preserve the organoleptic characteristics of the stored substance before its use in preparing a beverage, the capsule 1 is preferably airtight, in particular by forming a barrier against the circulation of oxygen and moisture, both towards the inside of said capsule, to prevent the alteration of the substance it contains by ambient air and humidity, and towards the outside, in particular to prevent the drying out of a substance conditioned in a moist and / or fatty form.

[0045] In particular, to ensure optimal preservation of the substance, capsule 1 has the following characteristics:

[0046] - an oxygen transmission rate of less than 10 cm 3 / m 2 .day.atm, specifically of no more than 5 cm 3 / m 2 .day.atm, and more specifically less than 1 cm 3 / m 2 .jour.atm, measured according to ASTM D3985; a water vapor transmission rate of less than 60 g / m 2 .24h, and more specifically less than 10 g / m 2 .24h, measured according to ASTM E96 standard in tropical conditions (38°C and 90% humidity).

[0047] With such characteristics, capsule 1 can notably be stored:

[0048] - before it is filled with a beverage preparation substance:

[0049] at a temperature between 15 and 25°C, and up to 50°C for a maximum of 6 weeks during its transport;

[0050] - after filling: in a dry and temperate place, with a maximum ambient humidity level between 35 and 55%.

[0051] To do this, the body 1a of capsule 1 can be subjected to a preliminary treatment to close the pores of the cellulose layer constituting it, in order to form a first barrier against oxygen and water vapor.

[0052] Furthermore, the use of a cellulose pulp comprising microfibrillated cellulose MFC contributes favorably to the sealing of capsule 1 against oxygen and water vapor.

[0053] Alternatively, an additional sealing coating and / or label may be applied to the outer surface 2b of the side wall 2, in order to reinforce and / or provide the specific oxygen and / or water vapor barrier properties required to ensure the preservation of the substance's organoleptic properties.

[0054] Similarly, the lids ensure a tight seal for capsule 1, notably by forming a barrier against oxygen and moisture. For this purpose, the lids can be made of a film according to document WO-2022 / 112613.

[0055] Capsule 1 is specifically designed for preparing hot beverages such as coffee, tea, or infusions. To do this, capsule 1 can be placed in the piston housing of a machine designed for this purpose, where at least one pin passes through to inject extraction liquid, such as hot water, into the substance contained within capsule 1. In particular, capsule 1 is held in the piston housing during the extraction of the beverage, before being expelled by gravity after the piston is removed at the end of the preparation process.

[0056] The injection of the liquid induces an increase in pressure in the substance conditioning compartment, so as to allow, after rupture of a frangible wall of capsule 1, the flow of the drink out of said capsule.

[0057] During beverage preparation, capsule 1 is subjected to an injection of water at a temperature between 86°C and 90°C and under a pressure of up to 20 bars, for a duration of approximately 2 minutes. Specifically, to prepare a coffee-type beverage, the quantity of water injected into capsule 1 is between 40 mL and 150 mL.

[0058] The body 1a may also include a coating film which is associated on the inner surface 2a of the side wall 2, in particular by thermoforming after formation of said body, or jointly with thermoforming of said body.

[0059] The coating film may be based on thermoplastic polymers, for example PBS (Poly(Butylene Succinate)), which are compostable and advantageously biodegradable. The film may possess properties, including softening and elongation, that allow for thermoforming. In particular, the coating film is arranged to prevent direct contact between the packaged substance and the body 1a of the capsule 1, in order to protect the substance from aromatic contamination by the material of the body.

[0060] After thermoforming, the coating film has a lower portion positioned opposite the base 3. This lower portion closes off the lateral portion of the film that is associated with the lateral wall 2 of the body 1a. In particular, a lower passage as described above can be formed through the base by cutting the lower portion of the coating film. Indeed, cutting the coating film eliminates the potential difficulty of piercing it with the injection equipment for extracting liquid during beverage preparation, especially since the film possesses the elasticity necessary for its thermoforming.

[0061] Advantageously, the cutting of the coating film is carried out so as to form a lower passage over substantially the entire dimension of the bottom 3 of the body 1a of the capsule 1. Thus, a bottom 3 is obtained with a peripheral conical rim 3a whose inner face 8 is coated with a coating rim formed by cutting in the coating film.

[0062] The lower passage can then be closed by means of a lower operculum, said lower operculum being adapted to be pierced by the injection means into the piston housing.

[0063] In particular, the lower operculum is arranged to be easily traversed by the injection means, notably more easily than a solid base 3 of the body 1a of a capsule 1, a fortiori coated with the film, in order to limit the risks of deformation of said capsule during its use.

[0064] Thus, it is possible, in particular for a capsule 1 formed from a material with a limited ecological impact, to combine the preservation of the organoleptic properties of the substance over time and an optimal drilling of the bottom 3 of said capsule for its use.

[0065] Advantageously, the lower lid is sealed to the inner face 8 of the conical rim 3a, and in particular to the coating rim formed by cutting the lower passage 7. This arrangement ensures the seal of the capsule 1 at the interface between the coating film and the lower lid, especially in the case of a body 1a made of a porous material such as cellulose. The capsule 1 shown in Figure 1 is adapted to be placed in a machine where it is held by a piston equipped with pins to pierce its lower lid. Furthermore, the lower lid is pierced by at least one pin to inject extractor fluid into the substance contained in the capsule 1, which induces a pressure increase in the compartment to allow, after the upper lid breaks, the flow of the beverage through the opening 5.

[0066] In particular, the lower lid can be arranged to be easily passed through by the injection pins, notably more easily than the cellulose base 3 of capsule 1, in order to limit the risks of deformation of said capsule during its use.

[0067] Furthermore, the machine includes a base equipped with a network of pins, on which the upper lid is designed to break under the effect of the increase in pressure in capsule 1, in order to allow the flow of the drink.

[0068] The rim 4 further has a lower wall 4b which is laterally projecting from the lateral wall 2, the capsule 1 being equipped with a ring 10 which is attached to said lower wall having an upper face 10a disposed to rest on said lower wall, as well as a free lower wall 10b which has a bearing surface 11 on which the piston is intended to rest during the preparation of the drink.

[0069] Advantageously, the upper face 10a is supported on the lower wall 4b continuously over at least its entire surface which is arranged opposite the span 11. In particular, the upper face 10a is flat so as to be in planar support on the lower wall 4b.

[0070] This arrangement provides rigidity to the capsule 1 at its annular rim 4, which holds it in the piston housing during beverage preparation. This ensures good contact between the machine and the rim 10, even if the body 1a swells and / or softens due to the extraction liquid, thus facilitating the subsequent expulsion of the capsule 1 by gravity after the beverage has been prepared.

[0071] Ring 10 is made of compostable polymer material according to EN 13432, and has a rigidity greater than that of body 1a, which is made from cellulose. Therefore, ring 10 can fulfill its function of stiffening the annular rim 4 while having a limited environmental impact.

[0072] To ensure a sealing function between the piston and the capsule 1 during the preparation of a beverage, the ring 10 has at least one sealing lip 12 which is formed in a projecting direction axially from the bearing surface 11 of the lower face 10b of said ring, on which the edge of the piston is intended to come to rest when closing its housing, in order to limit leakage of liquid between the annular rim 4 and said piston during the preparation of a beverage.

[0073] The ring 10 is made from a biopolymer, specifically a thermoplastic, and preferably based on polylactic acid (PLA) or polyhydroxyalkanoate (PHA). These materials, in addition to being compostable and food-grade, allow for the easy injection molding of rings 10 with thin walls, including a sealing lip 12 as described previously. Furthermore, the biopolymer used is chosen for its resistance to hot water, particularly temperatures up to 90°C.

[0074] In the embodiments shown, the ring 10 has an inner crown 13 which has an external bearing surface 13a arranged opposite the lip, as well as an internal bearing surface 13b surrounding the lateral wall 2 of the body 1a.

[0075] In the figures, the lower face 10b of the ring 10 also has an outer ring 14 which has an inner bearing surface 14b arranged opposite the sealing lip 12, so as to form with the outer bearing surface 13a of the inner ring 13 a groove 15 in which said lip is disposed. Thus, when the capsule 1 is placed in the piston housing, the peripheral edge of said piston comes to be positioned between the outer rings 14 and inner rings 13 by crushing the sealing lip 12, the piston-rings 13, 14-lip 12 assembly forming a sealing baffle to limit in a particularly reliable way the leakage of extractor liquid from said housing during the preparation of a beverage.

[0076] Advantageously, as shown in particular in Figures 2 and 5, the groove 15 has a bottom 16 which extends axially in retreat from the rest of the lower face 10b of the ring 10, which provides a space of sufficient volume to allow the lip 12 to deform under the effect of the axial pressure exerted on it by the piston when closing the housing, while leaving the groove 15 an axial depth which is sufficient to accommodate the edge of said piston, and thus limit the risks of leakage of extracting liquid through said groove.

[0077] At least one of the internal 14b and external 13a bearing surfaces may have a taper which is oriented towards the lip 12, in order to improve the guidance of the edge of the piston towards said lip, and thus the sealing.

[0078] In particular, in figures 2 to 6, the internal bearing surfaces 14b and external bearing surfaces 13a each have a taper oriented towards the lip 12, which forms a particularly effective guiding structure for the edge of the piston, which is thus aligned axially with said lip to better interact with it when closing the housing.

[0079] The inner ring 13 has an axial height H1 which is sufficiently large to provide increased rigidity to the capsule 1, particularly at the interface between its annular rim 4 and the upper part of the side wall 2. In particular, the axial height H1 of the inner ring 13 is greater than the respective axial heights H2, H3 of the sealing lip 12 and the outer ring 14. In relation to figures 2 to 6, the inner ring 13 has a base 17 for connection to the rest of the ring 10 and a free end 18, the axial height H1 of said inner ring being measured between the upper part of said base and said free end.

[0080] As shown in these figures, the connecting base 17 forms an elbow between the upper face 10a of the ring and the inner bearing surface 13b of the inner ring 13, the angle of said elbow being between 90° and 100°. In particular, the base 17 as shown has an angle greater than 90°, in order to conform to the frustoconical geometry of the interface between the annular rim 4 and the portion of the lateral wall 2 against which the inner ring 13 is positioned. Specifically, the base 17 bears against the interface between the annular rim 4 and the portion of the lateral wall 2 so as to ensure the expected stiffening of the capsule 1 at said interface. Furthermore, the upper face 10a bears against the lower wall 4b over a sufficient area to stiffen the rim 4, in particular over the entire surface between the base 17 and the outer end ring 20.

[0081] Advantageously, the ring 10 is associated with the body 1a of the capsule 1 by fitting its inner ring 13 around the lateral wall 2 of said body, which makes it possible to do without the use of an adhesive, and thus to facilitate the assembly of the capsule 1.

[0082] Advantageously, the internal bearing surface 13b of the inner ring 13 fits within an internal diameter that is smaller than the mounting diameter of the side wall 2, so as to exert a radial clamping force on said wall, and thus eliminate the risks of relative movement of the ring 10 and the body 1a of capsule 1 after their assembly.

[0083] To assemble the ring 10 to the body 1a of capsule 1, the inner crown 13 is fitted around the side wall 2 through the bottom 3, then by axial sliding along said side wall, until the upper wall 10a of said ring is brought into axial support under the lower wall 4b of the annular rim 4.

[0084] Given the rigidity of the material forming the ring 10, the connecting base 17 may have a constriction 19 arranged to promote the bending of the inner ring 13 relative to the rest of the ring 10, particularly during its sliding along the side wall 2 when assembling said ring to the body 1a of the capsule 1.

[0085] After their manufacture, the rings 10 can be packaged in batches by stacking one on top of the other after their manufacture, in order to facilitate their storage and delivery to a capsule production site 1, for their subsequent assembly to bodies 1a to form capsules 1.

[0086] Advantageously, the base 17 and the free end 18 of each ring 10 can present complementary geometric means of coupling the stacking of one ring 10 on top of the other.

[0087] As shown in Figures 2 and 3, the constriction 19 is formed on the inner wall 13b of the inner ring 13, so as to receive the free end 18 of another ring 10 when they are stacked, as shown by the arrows F in Figure 3. In particular, the constriction 19 has a geometry complementary to that of the free end 18 of the inner ring 13.

[0088] In figures 1, 1a, 2, 5 and 6, the ring 10 has a radial dimension which is sufficient to allow it to extend over substantially the entire radial dimension of the lower wall 4b of the annular rim 4, in order to provide rigidity over the whole of said annular rim.

[0089] Furthermore, in these same figures, the ring 10 has an outer end crown 20 which is formed in axial projection from the free lower face 10b of said ring, so as to be disposed on the outer edge 24 of the lower wall 4b of the rim 4, and thus to form on said edge a buttress to limit the risks of bending at the level of the outer portion of said ring.

[0090] The axial height H1 of the inner ring 13 is greater than the axial height H4 of the outer end ring 20, so that said end ring does not hinder the cooperation between the free end 18 of said inner ring with the constriction 19 of another ring 10 when stacking them, as shown in Figure 3.

[0091] In particular, the ring 10 has a reduced depth annular indentation 21 which is formed on its upper wall 10a, in order to receive the free end 22 of the outer end crown 20 of another ring 10 when they are stacked.

[0092] Alternatively, as shown in Figure 6, the inner ring 13 has an axial height H1 which is large enough to allow the nesting of two capsules 1, each equipped with a ring 10, by pressing its free end 18 against the upper wall 10a of the ring 10 equipping the other capsule 1. Thus, the capsules 1 can be packaged in batches by nesting one inside the other after their assembly, in order to be supplied to producers for their subsequent loading with a substance for the preparation of a beverage.

[0093] In relation to figures 1a and 2, the outer end ring 20 has angular recesses 23 opening into the upper face 10a of the ring 10. In particular, these angular recesses 23 are separated by material bridges 25 allowing to combine weight saving and rigidity.

Claims

DEMANDS 1. Capsule (1) intended to contain a substance for the preparation of a beverage by placing said capsule in the housing of a piston, said capsule comprising a body (1a) defining a compartment (6) for packaging a substance for the preparation of the beverage, said body having a side wall (2) bordered on either side by respectively a bottom (3) and a rim (4) surrounding an opening (5) of said body, said rim having a lower wall (4b) projecting laterally from said side wall, said capsule being equipped with a ring (10) which is attached to said lower wall having an upper face (10a) bearing against said lower wall and a free lower face (10b) having a bearing surface (11) on which the piston is intended to bear,said body being formed from cellulose and said capsule being characterized in that the ring (10) is made of compostable polymer material according to standard EN 13432, having a rigidity which is greater than that of the body (1a) formed from cellulose, said ring having at least one sealing lip (12) which is formed projecting in an axial direction from the bearing surface (11) of the free lower face (10a) of said ring.

2. Capsule (1) according to claim 1, characterized in that the upper face (10a) is supported on the lower wall (4b) continuously over at least the whole of its surface which is arranged opposite the bearing surface (11).

3. Capsule (1) according to one of claims 1 or 2, characterized in that the ring (10) has an inner crown (13) having an external bearing surface (13a) arranged opposite the lip (12), and an internal bearing surface (13b) surrounding the lateral wall (2) of the body (1a).

4. Capsule (1) according to claim 3, characterized in that the axial height (H1) of the inner ring (13) is greater than the axial height (H2) of the lip (12).

5. Capsule (1) according to any one of claims 3 or 4, characterized in that the lower face (10b) of the ring (10) has an outer ring (14) having an inner bearing surface (14b) disposed opposite the lip (12) to form with the outer bearing surface (13a) of the inner ring (13) a groove (15) in which said lip is disposed.

6. Capsule (1) according to any one of claims 3 to 5, characterized in that the inner ring (13) has a base (17) for connection to the rest of the ring (10) and a free end (18).

7. Capsule (1) according to claim 6, characterized in that the base (17) and the free end (18) have complementary geometries for coupling the stack of one ring (10) onto the other.

8. Capsule (1) according to one of claims 6 or 7, characterized in that the base (17) has a constriction (19) promoting the bending of the inner crown (13) relative to the rest of the ring (10).

9. Capsule (1) according to any one of claims 6 to 8, characterized in that the connecting base (17) forms a bend between the upper face (10a) of the ring (10) and the inner bearing surface (13b) of the inner ring (13), the angle of said bend being between 90 and 100°.

10. Capsule (1) according to any one of claims 1 to 9, characterized in that the ring (10) has an outer end crown (20) which is formed in axial projection from the free lower face (10b) of said ring.

11. Capsule (1) according to claim 10, characterized in that the outer end ring (20) is disposed on the edge (24) of the lower wall (4b) of the rim (4).

12. Capsule (1) according to either of claims 10 or 11, characterized in that the outer end ring (20) has angular recesses (23) opening into the upper face (10a) of the ring (10).

13. Capsule (1) according to any one of claims 1 to 12, characterized in that the ring (10) is fitted around the lateral wall (2) of the body (1a).

14. Capsule (1) according to claim 13, characterized in that the ring (10) has an inner diameter which is less than the insertion diameter of the side wall (2) so as to exert a radial clamping force on said wall.

15. Capsule (1) according to any one of claims 1 to 14, characterized in that the ring (10) is made from biopolymer, in particular thermoplastic.

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