WO2023031095A1

WO2023031095A1 - Capsule for producing a beverage and method for manufacturing a capsule

Info

Publication number: WO2023031095A1
Application number: PCT/EP2022/073908
Authority: WO
Inventors: Lise ZEBOUDJ; Najat BOUZAMBOU; Daniel Abegglen
Original assignee: Société des Produits Nestlé S.A.
Priority date: 2021-08-30
Filing date: 2022-08-29
Publication date: 2023-03-09
Also published as: CN117897346A

Abstract

Capsule (1) for use in a beverage preparation machine, said capsule comprising : • a capsule body (2) defining a chamber (21), said capsule body comprising : • one or more side walls (22), said walls extending axially towards a top opening (23), and • a circumferential flange (24) that extends radially outward from the one or more side walls, and • a top membrane (3) attached to at least a part of the upper surface (241) of the said circumferential flange and closing the top opening, and adapted to be punctured for liquid injection into the capsule, the top membrane and the flange extending globally along a common plane (P), and • a bottom membrane (4), provided inside the chamber (21) so as to delimit between the top membrane (3) and said bottom membrane an ingredient chamber, and • an opening device (5) provided inside the chamber and adapted to open the chamber.

Description

CAPSULE FOR PRODUCING A BEVERAGE AND METHOD FOR MANUFACTURING A CAPSULE

Field of the invention

The invention relates to a capsule for use in a beverage preparation machine, a method for manufacturing a capsule, and a sealing die.

Background of the invention

Beverage preparation machines allow a consumer to prepare at home various types of beverages, for instance coffee-based beverages.

Today, most beverage preparation machines for in-home beverage preparation comprise a system made of a machine which can accommodate portioned ingredients for the preparation of the beverage. Such portions can be soft pods or pads, or sachets, but more and more systems use semi-rigid or rigid portions such as rigid pods or capsules. In the following, it will be considered that the beverage machine of the invention is a beverage preparation machine working with a rigid capsule.

The machine comprises a receptacle for accommodating said capsule and a fluid injection system for injecting a fluid, preferably water, under pressure into said capsule. Water injected under pressure in the capsule, for the preparation of a coffee beverage, is preferably hot, that is to say at a temperature above 70°C. However, in some particular instances, it might also be at ambient temperature. The pressure inside the capsule chamber during extraction and/or dissolution of the capsule contents is typically about 1 to 8 bar for dissolution products (for the dissolution of soluble ingredients like milk powder, chocolate powder, instant coffee or instant tea), and about 2 to 12 bar for extraction of roast and ground coffee.

The principle of extracting and/or dissolving the contents of a closed capsule under pressure is known and consists typically of confining the capsule in a receptacle of a machine, injecting a quantity of pressurized water into the capsule, generally after piercing a face of the capsule with a piercing injection element such as a fluid injection needle mounted on the machine, so as to create a pressurized environment inside the capsule either to extract the substance or dissolve it, and then release the extracted substance or the dissolved substance through the capsule. Capsules allowing the application of this principle have already been described for example in EP1472156 and in EP 1784344 B1. These capsules present the specific features of enclosing the beverage ingredient in a chamber closed by a top membrane through which water is injected and by a bottom membrane configured to be opened further to the increase of water pressure inside the chamber. Upon liquid injection inside the chamber, pressure deforms the bottom membrane until opening elements positioned close to said bottom membrane pierces the deformed membrane, giving way to the beverage prepared inside the chamber towards the outside of the capsule, e.g. into a cup. As mentioned above, these capsules are rigid capsules usually made of plastic material. In order to improve either the recyclability or compostability of these capsules, new materials answering these objectives must be used.

In particular, two different solutions can be developed :

- one to enable recyclability of said capsules by proposing a capsule made of polypropylene (PP) material only. Indeed, in the current existing capsules, the different parts of the capsules are generally made of different types of material, which can make recycling of the used capsule difficult depending on the capabilities of recycling plants. A capsule with a body and a top membrane made of PP would be easier to recycle.

- another to enable biodegradability of said capsules by proposing a capsule made of biodegradable materials only.

In both situations, problems were encountered when the nature of the materials was changed.

The problem of the capsule made of 100 % PP material is that, by using a top membrane made of PP only, the temperature used for sealing this PP top membrane to the capsule body had to be reduced from 220°C down to 170-175°C to avoid damaging this PP membrane. This temperature is applied at the step of heat sealing in the manufacturing line of the capsules. Heat sealing consists in covering the opened top of the capsule with a membrane and then pushing a cutting and heating head on the membrane to cut the top membrane to the dimension of the capsule and to heat seal the membrane to the cup simultaneously. While manufacturing these new capsules in the usual manufacturing line, it has been observed that the new produced capsules presented lower resistance to pressure generated in the capsule during the beverage extraction.

Based on the principle of beverage preparation with the above mentioned capsule, pressure increases inside the capsule further to the introduction of water until the bottom opening means pierces the bottom membrane. Accordingly, to get this effect, it is essential that the top membrane is able to resist a higher pressure than the bottom membrane. But with the new recyclable capsules produced with the current manufacturing line, it was observed that the top membrane separates off from the capsule body during beverage extraction.

One first solution to improve the sealing was to lengthen the step of heat sealing at 170-175°C, but that immediately created a problem of rate of the manufacturing line impacting the other steps of the manufacturing line and above all reducing the number of capsules produced per hour.

The problem of the other capsules made of biodegradable materials is the sealing of the top membrane on the capsule body too. It was observed that the compostable materials of the membrane and the capsule body separates easily when the pressure increases inside the capsules during beverage preparation, preventing a correct preparation of the beverage.

Consequently, whatever the nature of the materials the capsule is made of, the top membrane needs to properly close the chamber during the rise of the pressure in the chamber up to a minimum pressure without any leakage. This is important because during the extraction or dissolution of the beverage ingredient a defined pressure needs to be ensured.

Therefore, it is an object of the present invention to overcome the afore-mentioned drawbacks. That is, it is in particular an object of the present invention to provide a capsule that has a higher resistance in terms of resistance to burst, i.e. to provide a capsule that better resists the pressures in the capsule which are required for preparing the respective beverage.

These and other objects, which become apparent upon reading the following description, are solved by the subject matter of the independent claims. The dependent claims refer to preferred embodiments of the invention.

Summary of the invention

According to a first aspect of the invention, there is provided a capsule for use in a beverage preparation machine, said capsule containing a soluble and/or extractable food material, said capsule comprising :

- a capsule body defining a chamber, said capsule body comprising :

. one or more side walls, said walls extending axially towards a top opening, and

. a circumferential flange that extends radially outward from the one or more side walls, and

. a bottom beverage outlet.

- a top membrane attached to at least a part of the upper surface of the said circumferential flange and closing the top opening, and adapted to be punctured for liquid injection into the capsule, the top membrane and the flange extending globally along a common plane (P), and

- a bottom membrane provided inside the chamber so as to delimit between the top membrane and said bottom membrane an ingredient chamber, and

- an opening device provided inside the chamber and adapted to open the chamber by relative engagement of said opening device with the bottom membrane under the effect of the liquid pressure increase in the ingredient chamber during injection of said liquid, and wherein the upper surface of said flange comprises at least one circumferential transverse fixing section, said fixing section extending transversely to the common plane, and wherein the top membrane is attached at least to said fixing section.

By circumferential, it is meant that this fixing section is present on the whole circumference of the flange. Generally, the shape form of this fixing section is identical along the whole circumference.

This fixing section is transverse to the common plane P and extends from said plane.

Thereby, the fixing interface between the fixing section and the top membrane can be provided in a direction transverse to the top membrane main orientation. This advantageously effects that the force required to detach the top membrane from the flange is increased.

As a result, the strength needed to tear the top membrane extending along the top plane (P) from the fixing section is increased, because the resulting force to tear is transverse to said plane.

The resistance to remove the top membrane from the fixing section can be increased without increasing the temperature or the time to seal the membrane. Capsule materials having a weak attachment can be used.

Hence, the resistance of the capsule in terms of resistance to burst, in particular during beverage preparation at defined (high) pressures, is increased in a very cost-effective and easy way. Accordingly, the capsule provides a great flexibility to choose materials without having an adverse effect on the ability of the capsule to resist defined pressures. Therefore, the capsule also makes it possible to improve its environmental sustainability, e.g. by choosing the material of the capsule in a specific (eco-friendly) manner. In particular, with the specific shape of the fixing section one may use materials that on the one hand are more prone to separation from body but on the other hand have advantageous features such as being more eco-friendly, e.g. due to an increased recyclability or biodegradability. Further, no additional fixing steps and/or no additional time for fixing in the manufacturing or production of the capsule is required in order to improve the fixation of the top membrane. This because the effect of improved fixation and resistance of the top membrane is provided by the specific transverse fixing section. Besides, other parameters in the manufacturing of the capsule can be advantageously modified without having an adverse effect on the resistance of the capsule in terms of bursting. For example, the temperature required for heat sealing can be reduced without decreasing the time to heat seal. This also reduces the risk of damaging parts of the capsules which are involved in the fixing process, such as the top membrane and/or the capsule body.

The transverse fixing section can comprise at least one circumferential recess and/or at least one circumferential protrusion around the top opening. The fixing section can extend upwardly from the upper surface of the flange and can form a circumferential protrusion on the flange, such as an annular bump or ridge around the top opening. This protrusion extends circumferentially around the top opening of the chamber. The transverse fixing section can comprise a plurality (more than one) of protrusions preferably arranged concentrically relative to one another.

Alternatively, the fixing section can extend downwardly from the upper surface of the flange and can form a recess or groove inside the upper surface of the flange. This recess forms n annular groove, that extends circumferentially around the top opening of the chamber. The transverse fixing section can comprise a plurality (more than one) of recesses preferably arranged concentrically relative to one another.

In another embodiment, the transverse fixing can comprise at least one protrusion and at least one recess.

Preferably, the at least one circumferential transverse fixing section extends by a length £ of :

- at least 0.2 mm,

- preferably at most 0.5 mm, and is preferably comprised between 0.2 and 0.35 mm.

This length corresponds to the most important dimension of the transverse fixing section along the direction perpendicular to the common plane (P).

Preferably, this dimension is not too important to avoid fragilizing the flange.

Preferably, the at least one circumferential transverse fixing section (7) extends by a width of at least 0.8 mm, preferably at most 2 mm, and is preferably comprised between 0.8 and 1.8 mm.

This width corresponds to the most important dimension of the transverse fixing section ; it extends radially and along the common plane (P).

Preferably, the at least one circumferential transverse fixing section comprises at least one radially inward end and, at said radially inward end, the circumferential transverse fixing section extends transversely to the common plane (P) by an angle (a) of at least 10°, preferably at most 45°. Preferably, at said radially inward end, the circumferential transverse fixing section extends along a straight shape, such as a chamfer. Preferably the at least one circumferential transverse fixing section is positioned between the radially inward end of the flange and the radially outward end of the flange.

Accordingly, it is preferred that the top membrane is not attached near the ends of the flange, but rather preferably on the upper surface of the flange in between these two ends.

Indeed, the manufacturing tools, in particular the heating sealing die used to attach the top membrane to the flange are usually designed to apply heat on a section of the flange positioned in between these two ends because in the same step this manufacturing tool heats and cuts the top membrane on the capsule body.

Accordingly, it is preferably to use the advantages of such manufacturing tool in the current implementation of the invention.

Although the top membrane can be attached along the whole upper surface of the flange - from the inward and to the outward end - generally, the top membrane is attached to the transverse fixing section only.

Preferably, the circumferential transverse fixing section comprises at least one recess, said recess extending transversely to the common plane (P) and from the upper surface of the flange inside the flange, and the bottom of the said recess presents a round shape.

Such a shape enables easy manufacturing of a capsule body with such a recess in the flange, in particular during the manufacturing of the capsule body at the step of removal from a mould,

- to ease material flow if the shape is not pre-made in the capsule but at the time of sealing.

Preferably, each of the radially inward side and the radially outward side of this recess present straight surfaces.

Such a shape enables :

- easy manufacturing of a capsule body with such a recess in the flange, in particular during the step of removal from a mould,

- facilitate the introduction of the heating and sealing die in the recess,

In one embodiment, the radially inward side and/or the radially outward side of the recess can form a chamfer.

The at least one chamfer may form, in a cross-sectional view, a symmetrical or asymmetrical shape of the recess. In a cross-sectional view, the radially inward and the radially outward chamfers may be symmetrical relative to the remainder of the recess or a symmetry axis going through the remainder of the recess.

Alternatively, the recess may comprise only the radially outward chamfer or the radially inward chamfer and thereby form an asymmetrical shape. The respective other side is thus not chamfered but, for example, perpendicular to the upper flat surface of the flange.

When the circumferential transverse fixing section comprises at least one protrusion rising upwardly from the upper surface of the flange, said protrusion may be shaped corresponding to the above described recess so that the above description with respect to the recess applies correspondingly to the protrusion. Preferably, the protrusion is complementary formed to the above described recess.

Usually the flange comprises a flat surface from which the protrusion protrudes and/or from which the recess recedes.

In one embodiment, the capsule body and the top membrane are made of the same recyclable plastic, such as polypropylene.

“Recyclable” means that at least part and preferably all of the capsule can be converted into a single type of material or into several types materials that are separated from one another. Preferably, the capsule body is made of polypropylene and the top membrane is made of polypropylene. As such, a particularly improved recyclability is achieved compared to capsules, where the capsule body is made of PP but the top membrane is a multilayer component comprising PP and other materials in particular a PET layer. The transverse fixing section guarantees a stronger attachment of the different parts of PP materials between each other at lower temperature of sealing.

In another embodiment, the capsule body and the top membrane can be made of a compostable and/or biodegradable material. A “biodegradable and/or compostable material” may be understood as any material that can be broken down into environmentally innocuous products by (the action of) living things such as microorganisms (bacteria, fungi, algae, etc.). The environmentally innocuous products, into which the biodegradable material is broken down, may be water, carbon dioxide, and biomass. Biodegradation may take place in an environment with the presence of oxygen (aerobic) and/or otherwise without the presence of oxygen (anaerobic). International standards (such as EU13432 or USASTMD6400) specify technical requirements and procedures for determining compostability of a material.

The transverse fixing section guarantees a stronger attachment of the different parts of compostable and/or biodegradable materials between each other.

According to a second aspect of the invention, there is provided a method for manufacturing a capsule such as described above, said method comprising the steps of : - providing a capsule body defining a chamber, said capsule body comprising :

. one or more side walls, said walls extending towards a top opening (23), and

. a circumferential flange that extends radially outward from the one or more side walls, said flange extending along a plane (P), and

. a bottom outlet, wherein the upper surface of said flange comprises at least one circumferential transverse fixing section, said fixing section extending transversely to the plane (P),

- introducing an opening device inside the capsule body,

- attaching a bottom membrane inside the capsule body and above the opening device,

- filling the capsule body with beverage ingredient,

- fixing a top membrane to the upper surface of the flange of the capsule body by applying heat to the top membrane positioned along the flange with a heating die, wherein the heating die presents a shape complementary to the transverse fixing section of the flange and heats and presses the top membrane in the at least one transverse fixing section of the capsule.

The sealing die is adapted to seal by heat. Accordingly, the sealing die may comprise a heat conductivity. The sealing die may be a single or monolithic part, e.g. may be made from a single block of material. Preferably, the sealing die has the form of a ring. The sealing die may consist of a single material such as metal. The sealing die may also comprise one or more tool elements (e.g. integrally formed with the sealing section) that may be used in the production of a capsule. For example, the one or more tool elements comprise a cutting element that is adapted to cut or punch a membrane foil to thereby provide the top membrane. The sealing die may be in the form of a sealing head.

Brief description of the drawings

In the following, the invention is described exemplarily with reference to the enclosed figures, in which :

- Figure 1A shows a schematic cross-sectional view of a current existing capsule and Figure 1 B is a perspective cross-section view of an existing alternative embodiment,

- Figure 2A shows a schematic cross-sectional view of the upper part of a capsule according to a first preferred embodiment of the invention,

- Figure 2B is a magnified part of the recess in the flange of the capsule of Figure 2A,

- Figure 3 shows a schematic cross-sectional view of the upper part of a capsule according to a second preferred embodiment of the invention,

- Figure 4 shows a schematic cross-sectional view of a capsule according to a third embodiment of the invention,

- Figure 5 shows a schematic cross-sectional view of a sealing die according to the first preferred embodiment of the invention,

- Figure 6 shows a schematic cross-sectional view of a sealing die according to the second preferred embodiment of the invention,

- Figure 7 shows a schematic cross-sectional view of the sealing die according to another embodiment of the invention,

- Figure 8 schematically shows a manufacturing method according to the invention.

Detailed description of exemplary embodiments

Figure 1 A illustrates an existing capsule 1 adapted for use in a beverage preparation machine. The capsule 1 comprises a capsule body 2 with one or more side walls 22 that extend axially from a bottom towards a top. The side walls extend towards a top opening 23. At the top opening 23, the body comprises a circumferential flange 24 that extends radially outward from the one or more side walls. The flange 24 is usually integrally formed with the one or more side walls 22. The flange preferably extends around the opening 23 in the form of a closed ring. The flange comprises an upper surface 241 facing the top and a lower surface. The lower surface preferably comprises, or consists of, a flat surface.

Generally, the transversal cross section of the body capsule is circular from the bottom to the top and the flange is circular too as illustrated in the perspective view of Figure 1 B.

The one or more side walls delimit a chamber 21 for containing a soluble and/or extractable beverage ingredient.

This soluble beverage ingredient is a water soluble powder ingredient and can be selected within the list of : instant coffee powder, milk powder, cream powder, instant tea powder, cocoa powder, soup powder, fruit powder or mixture of said powders. The powders can be agglomerated or sintered.

This beverage ingredient packed in the package can also be an ingredient able to be extracted or infused like a roast and ground coffee, or tea leaves. In that embodiment water extracts the beverage ingredient.

The capsule comprises a top membrane 3 that is fixed, sealed or attached to at least a part of the upper surface 241 of the circumferential flange and accordingly covers and closes the top opening 23. The top membrane 3 and the flange 24 extends globally along a common plane (P) corresponding to the plane of the top opening 23.

This top membrane is adapted to be punctured for liquid injection into the capsule. Preferably, the top membrane is pierceable by an injection needle of the beverage preparation machine which is adapted to inject an extraction liquid under pressure inside or into the chamber. Preferably, the puncturing operation is made at one single place by a water injection needle such as described in W02006/082064 or W02008/107281 .

The term "top membrane" should be understood as the membrane which is pierced by the injection needle of machine, as opposed to the "bottom membrane" (such as described below) which should be understood as the membrane located on the opposite side of the capsule 1. This definition is such that "top" and "bottom" membranes are defined whatever the position of the capsule 1 within the machine, when both capsule and machine are engaged in a functional manner.

The capsule comprises a bottom membrane 4 that closes the bottom of the chamber 21. Accordingly, the soluble and/or extractable beverage ingredient is enclosed between the top and bottom membranes. The top and bottom membranes delimit an internal space of the chamber configured to hold the beverage ingredient for the preparation of a beverage.

In one preferred embodiment, a distributor wall 9 can extend through the internal cross section of the chamber defining an inferior sub-chamber for the ingredient and a superior distribution chamber for the liquid. This distributor wall comprises small holes to distribute liquid uniformly on the ingredient.

The capsule comprises an opening device 5 adapted to open the chamber by relative engagement with the bottom membrane 4 under the effect of the liquid pressure increase in the chamber during injection of said liquid. The opening device 5 may comprise a rigid plate comprising opening elements such as spikes on its surface turned upwardly towards the bottom membrane 4. The opening device 5 may be generally referred to as "pyramid plate". Upon liquid injection inside the chamber 4, pressure builds up, which deforms the bottom membrane 4 against the opening means 5, until the bottom membrane is pierced, giving way to the beverage prepared inside the capsule 1 respectively chamber 21 below the opening device 5.

The capsule body comprises a bottom beverage outlet 25 at its bottom and below the opening device 5. The bottom of the capsule body preferably extends below the opening means to hold said opening means and collect the beverage to this beverage outlet 25 dispensing the beverage outside of the capsule 1 , e.g. into a cup (not illustrated).

The top membrane 3 is fixed to the flange 24 in such a way that the extraction liquid injected into the chamber 21 effects a pressure increase therein and reaches the pressure necessary to obtain the piercing of the deformed bottom membrane 4 by the opening device 5. The top membrane 3 is thus fixed to the flange in such a way that it does not detach at least until a defined pressure inside of the chamber is achieved. This defined pressure may be at least 2 bars, preferably at least 3 bars or at least 6 bars. Thereby, the fixation effects that the capsule 1 does not leak via the interface between the flange and the top membrane during beverage preparation.

Figure 2A shows a schematic cross-sectional view of the upper part of a capsule according to a first embodiment of the invention. The rest of the capsule is similar to the capsule of Figure 1.

In this capsule, the upper surface 241 of said flange comprises a circumferential transverse fixing section 7 to which the top membrane 3 is attached. By circumferential, it is meant that this fixing extension is present on the whole circumference of the flange as represented on the left and right sides of the cross-sectional view. Preferably the membrane is fixed to said area by heat sealing, the membrane comprising a heat sealant component at its lower face facing the upper surface of the capsule flange.

The transverse fixing section extends transversely to the common plane P of the top membrane, the flange and the top opening. By transversely, it is meant that this fixing section is not in this plane P but extends in a direction that crosses said plane. As a result, at least a part 71 of the surface of said fixing section is inclined or slanted relatively to the plane P. Figure 2B illustrates the slanted plane surface of the part 71 that forms and angle a with the plane P at the radial inward end 73 of the fixing section.

Preferably, the circumferential transverse fixing section 7 extends by a length £ of at least 0.2 mm. This length corresponds to the most important dimension of the transverse fixing section along the direction perpendicular to the common plane (P) as illustrated.

The flange may comprise one or more flat sections 6. Preferably, the upper part of the flange consists of the one or more flat parts 6 and the transverse fixing section 7. Each of the flat parts 6 comprises a flat surface, wherein these flat surfaces preferably extend along the plane P. One first flat part 6 is radially inward relative to the transverse fixing section 7 and the second flat part 6 is radially outward relative to said fixing section 7. Optionally, the top membrane 3 is not fixed to the one or more flat parts 6. Hence, the top membrane 3 may be fixed to the transverse fixing section 7 only.

According to this embodiment of Fig. 2A, the fixing section 7 is a recess extending transversely from the upper surface 241 of the flange inside the flange 24. As shown in Figure 2A, the recess may have, in a cross-sectional view, two straight chamfers 71 surrounding a bottom concave rounded shape 72 The chamfers 71 and the concave shape 72 preferably extend around the whole circumference of the opening 23.

Hence, the top membrane 3 is fixed to the fixing section 7 in a very advantageous manner. This fixation in particular effects that the top membrane 3 is not fixed along the single plane P that covers the opening 6. Instead, the top membrane 3 is fixed along different directions provided by the parts 71 and 72. Accordingly, the strength needed to tear the fixation until it breaks or detaches is increased. In particular, when pressure increases inside the capsule due to the filling with water, said water exerts a force at the intersection 241a between the side wall 22 and the flange 24, said force pushing the membrane 3 upwardly and away from the flange 24 as illustrated by the arrow A. This force can facilitate the separation of the top membrane 3 from the flange along the flat part 6. Yet, at the transverse fixing section 7, the new orientation of this fixing section decreases the impact of the upwardly oriented force on the sealing of the membrane and the flange.

As shown in figure 2A, the fixing section 7 comprises a radially outward chamfer and a radially inward chamfer 71 and the top membrane 3 is fixed to both of them. In this way, the fixation between the flange and the top membrane is even further improved, because fixation between these parts is present in even further different directions.

The capsule is not limited to a specific material.

In one embodiment, the capsule body 2 is recyclable and/or consists of a single material, such as polypropylene. In particular, the capsule body 2 and the top membrane 3. Accordingly, these both elements can be sealed together strongly by heat sealing at a lower temperature by implementing the circumferential transverse fixing section 7.

In another embodiment, the capsule may be made of compostable and/or biodegradable materials, in particular the capsule body 2 and the top membrane 3. Accordingly, even if the sealing between the compostable and/or biodegradable materials of these both elements is weak, their attachment can be reinforced with circumferential transverse fixing section 7.

Figure 3 exemplarily shows a capsule 1 according to a second embodiment of the invention. The capsule 1 corresponds to the embodiment of Figure 2A except that the cross-section shape of the circumferential transverse fixing section 7 is different : the radially inward chamfer 71 is not present.

In other embodiments not illustrated, the recess 74 may be replaced by a protrusion. That is, the circumferential transverse fixing section extends transversely from the upper surface of the flange above the flange.

Instead of the recess receding relative to the upper surface of the flange extending along the plane P in Figures 2A and 3, the protrusion protrudes. This protrusion may comprise a shape that is complementary shaped to the shape of the recess illustrated in Figures 2A and 3. Preferably, the protrusion comprises a ridge, such as an annular ridge, that extends around the opening 6.

The upper surface of the flange can comprise a plurality of protrusions that are concentrically arranged relative to one another. In one other embodiment not illustrated, the upper surface of the flange can comprise :

- at least one protrusion such as described above that extends transversely to the common plane P from the upper surface of the flange above the flange, and

- at least one recess such as described above that extends transversely inside the upper surface of the flange above the flange.

The protrusion(s) and recess(es) are concentrically arranged relative to one another.

Figure 4 shows a schematic cross-sectional view of the upper part of a capsule according to a third embodiment of the invention.

The upper surface 241 of the flange comprises one circumferential transverse fixing section 7 that is transverse to the common plane P and that is positioned at the radially outward end 241 b of the flange. The fixing section 7 consists in a plane chamfer 71 to which is attached the top membrane 3.

This embodiment is less preferred because generally during manufacturing, attaching the top membrane to the capsule body requires two different steps first to cut the membrane to the desired dimension and then to attach it to the recess 7.

Figure 5 shows a cross section of a sealing die 100A used for manufacturing of the capsule illustrated in Figure 2A. The sealing die 100A is adapted to seal and thus fix a top membrane to a fixing section of the flange of a capsule body. The sealing die 100A comprises an annular sealing section 170A configured to press and heat the membrane against the flange 241 of the capsule to fix the top membrane 3 to a fixing section of the flange of the capsule body. The annular heating portion 170A of the sealing die presents a shape complementary to the circumferential transverse fixing section 7 of the flange of the capsule of Figure 2A and an annular shape with a diameter such that the external surface of said portion OA can be positioned along the external surface of the transverse fixing section of the capsule and so that the top membrane positioned between these surfaces can be attached along the whole surface of the transverse fixing section.

For this reason, the annular heating portion VOA presents a cross section comprising two chamfers 171 and an intermediate convex portion 172 corresponding to the negative shape or conformal shape of the two chamfers 71 and the concave shape 72 of the transverse fixing section 71 of the capsule of Figure 2A.

By pressing the hot heating die on a top membrane 3 extending along the plane P defined by the capsule top opening and the flange of the capsule, the annular heating portion VOA enters inside the corresponding transverse fixing section 71 of the capsule and fixed it. In a similar manner, Figure 6 exemplarily shows a cross section of a sealing die 100B used for manufacturing the capsule illustrated in Figure 3.

For this reason, the annular heating portion 170B presents a cross section comprising one chamfer 171 only and a convex portion 172 corresponding to the negative shape or conformal shape of the chamfer 71 and the concave shape 72 of the transverse fixing section 71 of the capsule of Figure 3.

In a similar manner, Figure 7 exemplarily shows a part of the cross section of a sealing die 100C used for manufacturing another type of capsule (not illustrated).

The annular heating portion 170C presents a cross section comprising one convex portion 172 and a plane portion 173 that is positioned radially outwardly.

The capsule to be sealed by a top membrane with this heating die 170 presents a flange comprising a groove corresponding to the negative shape or conformal shape of the annular heating portion 170C that is a concave rounded shape. The top membrane is sealed along this concave shape and along a plane portion extending along the plane P of the capsule and positioned at a radially outwardly part from the concave portion.

It is preferred that when a part of the top membrane is attached to the upper flat surface of the flange of a capsule, this part is attached to a portion of the flange that is radially outwardly positioned compared to the transverse fixing section.

In other embodiments, the annular heating portion 170A, 170B, 170C, which are protrusions, can be replaced by a recess. For example, the recess may comprise a shape that is complementary shaped to the shape of a protrusion at the upper surface of the flange of the capsule.

The above description with respect to protrusion thus applies analogously to the recess.

In Figure 8, an exemplary manufacturing arrangement (e.g. a manufacturing line) that performs a preferred embodiment of a method for manufacturing a capsule 1 is shown. The capsule 1 may be the capsule of Figures 2A or 3 described above. The manufacturing arrangement comprises at least a fixing device 100 such as one or more of the sealing dies 100A, 100B described above.

In a first step (a), a capsule body 2 is provided. Prior to step (a), the opening device 5, the bottom membrane and the beverage ingredient were introduced via the top opening. Further, a raw material 30 is provided between the capsule body 2 and the fixing device 100. The raw material 30 may be provided in the form of a foil. In the first step (a), the fixing device 100 is in an initial position. In a second step (b), the fixing device 100 performs cutting and heat sealing of the top membrane to the fixing section 7 of the capsule body 2. The step of fixing may be performed by applying heat to the top membrane 3 that is contacted by the fixing device 100. In this way, the top membrane 3 is fixed to the fixing section 7.

Once the top membrane 3 is fixed to the fixing section 7, an advantageous fixation of the top membrane 8 to the fixing section 7 is achieved, as described above.

In a third step (c), which is optional, the fixing device 100 returns along the movement axis into its initial position. Thereby, a remainder of the raw material 20 remains and can subsequently move further to repeat steps (a) to (c) for manufacturing a further capsule 1.

Examples

In the following, examples with capsules according to the invention are described in comparison to comparative examples.

In each example, the resistance of the capsule to burst is measured. The procedure for such a measurement comprises the following steps: a) placing the capsule to be tested in a bell under airtight conditions; b) introducing compressed air (6 bars) inside the bell and through the hole at the bottom of the capsule and measuring pressure inside the bell; the tested capsule can be empty (no pyramid plate and no (aluminium) bottom membrane at the bottom of the body) or, if there are the pyramid plate and the (aluminium) bottom membrane, the air introduced through the bottom hole pierces easily the (aluminium) bottom membrane or wall; in both of these cases the results in terms of burst resistance of the top membrane are the same; and c) waiting for the bursting of the top membrane and measuring the corresponding pressure.

Example 1 - comparative

The capsule according to this comparative example comprises a capsule body with a flat flange with a fixing section for the membrane. Hence, the fixing section does not comprise any parts that extend transversely relative to one another. Sealing of the top membrane to this fixing section is performed with heat at a temperature of 220°C. The top membrane is non- recyclable and has the layer structure PET/alu/PP. Burst pressure measurement is carried out on a series (number to be confirmed) of such capsules and provided the following results (the pressures indicate the pressures at which the capsules burst, i.e. at which the top membrane separates from the capsule body, resulting in leakage):

In order to be extracted correctly inside the beverage preparation machine (e.g. an NDG “Nestle Dolce Gusto” machine), the capsules preferably present a burst pressure of at least 2.1 bar for product extracted at low pressure and at least 3.0 bar for other products extracted at high pressure.

Example 2 - comparative

The capsule according to this comparative example comprises a capsule body with a flat flange with a fixing section for the membrane. Hence, the fixing section does not comprise any parts that extend transversely relative to one another. Sealing of the top membrane to this fixing section is performed with heat at a temperature of 175°C. The top membrane is a recyclable multi-layer mono-material membrane made from PP. Burst pressure measurement is carried out on a series (number to be confirmed) of such capsules and provided the following results (the pressures indicate the pressures at which the capsules burst, i.e. at which the top membrane separates from the capsule body, resulting in leakage):

As can be derived from these results, the burst pressures are too low to enable the extraction of these capsules in the beverage machine. The membrane will delaminate during the beverage preparation.

Example 3 - according to the invention

The capsule according to this example comprises a capsule body with a flange having a fixing section that comprises a recess as a groove and that has a symmetrical design such as illustrated in Figures 2A and 2B . Sealing of the top membrane to these parts is performed with heat at a temperature of 220°C. The top membrane is a non-recyclable membrane and has the layer structure PET/alu/PP sealed. Burst pressure measurement carried out on a series of such capsules and provided the following results (the pressures indicate the pressures at which the capsules burst, i.e. at which the top membrane separates from the capsule body, resulting in leakage):

As can be seen, the values of the burst pressures are comparable to the values of the comparative example 1 .

Example 4 - according to the invention

The capsule according to this example comprises a capsule body with a flange having a fixing section that comprises a recess as a groove with the same symmetrical design of example 3. Thus, the symmetrical design comprises a first part and a second part that are transverse relative to one another, and the top membrane is sealed and thus fixed to these parts. Sealing of the top membrane to these parts is performed with heat at a temperature of 175°C. The top membrane is a recyclable multi-layer mono-material PP membrane. Burst pressure measurement is carried out on a series of such capsules and provided the following results (the pressures indicate the pressures at which the capsules burst, i.e. at which the top membrane separates from the capsule body, resulting in leakage):

As can be seen, the minimum values of the burst pressures increased and are always above 2.1 bar meaning a positive increase compared to the values of the same capsules with flat flange (comparative example 2).

Example 5 - according to the invention

The capsule according to this comparative example comprises a capsule body with a flange having a fixing section that comprises a recess as a groove with an asymmetrical design such as illustrated in Figure 3. Sealing of the top membrane to this fixing section is performed with heat at a temperature of 220°C. The top membrane is a non-recyclable membrane having the layer structure PET/alu/PP. Burst pressure measurement carried out on a series of such capsules and provided the following results (the pressures indicate the pressures at which the capsules burst, i.e. at which the top membrane separates from the capsule body, resulting in leakage):

As can be seen, the values of the burst pressures are improved compared to the values of the comparative example 1 which is the reference for having capsules working efficiently in the beverage machine.

Example 6 - according to the invention

The capsule according to this example comprises a capsule body with a flange having a fixing section that comprises a recess as groove with the same asymmetrical design illustrated in Figure 3. Sealing of the top membrane to this fixing section is performed with heat at a temperature of 175°C. The top membrane is a recyclable multilayer mono-material PP membrane. Burst pressure measurement is carried out on a series of such capsules and provided the following results (the pressures indicate the pressures at which the capsules burst, i.e. at which the top membrane separates from the capsule body, resulting in leakage):

As can be seen, the minimum values of the burst pressures increased and are always above 2.1 bar in average meaning a positive increase compared to the values of the same capsules with a flat flange (comparative example 2).

Example 7 - comparative

Capsules were produced with a capsule body made of a biodegradable material, namely polyhydroxyalkanoate (PHA), and a 120 micrometer top membrane made of PHA, too. The top membrane was fixed to an entirely flat fixing section of a flange of the capsule body. The average burst pressure was 8 bars.

Example 8 - according to the invention

Capsules were produced with a capsule body made of polyhydroxyalkanoate (PHA) and a 120 micrometer top membrane made of PHA, too. The top membrane was fixed to a fixing section of a flange of the capsule body, which fixing section comprises an asymmetrical shape with a groove in the flange such as shown in Figure 3. The average burst pressure was 10 bars.

Hence, the asymmetrical shape of the fixing section, to which the top membrane is fixed, effected that the burst pressure increased from an average of 8 bar in the comparative example 7 to an average up of 10.5 bars.

Example 9 - according to the invention

Capsules were produced with a capsule body made of a biodegradable material, namely polyhydroxyalkanoate (PHA), and a 150 micrometer top membrane made of PHA, too. The top membrane was fixed to a fixing section of a flange of the capsule body, which fixing section comprises an asymmetrical shape with a groove in the flange such as shown in Figure 3. Compared to example 8, the depth of the groove was changed from 2 mm to 0.5 mm. The average burst pressure increased from 10 bars to 11 bars.

It should be clear to a skilled person that the embodiments shown in the figures are only preferred embodiments, but that, however, also other designs of a capsule, sealing die and manufacturing arrangement for the method can be used.

List of references in the drawings : capsule 1 capsule body 2 chamber 21 side wall 22 top opening 23 flange 24 upper surface 241 radially inward end 241a radially outward end 241 b beverage outlet 25 intersection 26 top membrane 3 raw material 30 bottom membrane 4 opening means 5 plane section 6 transverse fixing section 7 radially inward or outward surface 71 bottom surface portion 72 radial inward end 73 heating die 100A, 100B, 100C annular heating portion 170A, 170B.170C chamfer 171 convex portion 172 plane portion 173 beverage ingredient 8 distributor wall 9

Claims

1. A capsule (1) for use in a beverage preparation machine, said capsule containing a soluble and/or extractable beverage ingredient, said capsule comprising :

- a capsule body (2) defining a chamber (21), said capsule body comprising :

. one or more side walls (22), said walls extending axially towards a top opening (23), and

. a circumferential flange (24) that extends radially outward from the one or more side walls, and

. a bottom beverage outlet (25), and

- a top membrane (3) attached to at least a part of the upper surface (241) of the said circumferential flange and closing the top opening, and adapted to be punctured for liquid injection into the capsule, the top membrane and the flange extending globally along a common plane (P), and

- a bottom membrane (4), provided inside the chamber (21) so as to delimit between the top membrane (3) and said bottom membrane an ingredient chamber, and

- an opening device (5) provided inside the capsule body (2) and adapted to open the ingredient chamber by relative engagement of said opening device with the bottom membrane (4) under the effect of the liquid pressure increase in the ingredient chamber during injection of said liquid, and wherein the upper surface (241) of said flange comprises at least one circumferential transverse fixing section (7), said fixing section extending transversely to the common plane (P), and wherein the top membrane (3) is attached at least to said fixing section (7).

2. A capsule (1) according to Claim 1 , wherein the transverse fixing section (7) can comprise at least one circumferential recess and/or at least one circumferential protrusion around the top opening.

3. A capsule (1) according to Claim 1 or 2, wherein the at least one circumferential transverse fixing section (7) is positioned between the radially inward end (241a) of the flange and the radially outward end (241b) of the flange.

4. A capsule (1) according to any one of the precedent claims, wherein the at least one circumferential transverse fixing section (7) extends by a length of at least 0.2 mm, preferably at most 0.5 mm, and is preferably comprised between 0.2 and 0.35 mm.

5. A capsule (1) according to any one of the precedent claims, wherein the at least one circumferential transverse fixing section (7) extends by a width of at least 0.8 mm, preferably at most 2 mm, and is preferably comprised between 0.8 and 1.8 mm.

6. A capsule (1) according to any one of the precedent claims, wherein the at least one circumferential transverse fixing section (7) comprises at least one radially inward end (73) and at said radially inward end (73) the circumferential transverse fixing section extends transversely to the common plane (P) by an angle of at least 10°, preferably at most 45°.

7. A capsule according to any one of the precent claims, wherein the circumferential transverse fixing section (7) comprises at least one recess, said recess extending transversely to the common plane (P) and from the upper surface of the flange inside the flange (24), and wherein the bottom (72) of the said recess presents a round concave shape.

8. A capsule according to the precent claim, wherein a radially inward side and a radially outward side (71) of said recess present straight surfaces.

9. A capsule according to any one of the preceding claims, wherein the top membrane (3) is fixed to the transverse fixing section (7) by heat sealing.

10. The capsule (1A, 1 B) according to any one of the preceding claims, wherein the capsule body (2) and the top membrane (3) are made of the same recyclable plastic, such as polypropylene.

11 . The capsule (1 A, 1 B) according to any one of claims 1 to 9, wherein the capsule body (2) and the top membrane (3) are made of compostable and/or biodegradable material.

12. A method for manufacturing a capsule (1 , 1A, 1 B) according to any one of Claims 1 to 11 , said method comprising the steps of :

- providing a capsule body defining a chamber (21), said capsule body comprising :

. one or more side walls (22), said walls extending towards a top opening (23), and

. a circumferential flange (24) that extends radially outward from the one or more side walls, said flange extending along a plane (P), and

. a bottom outlet (25), wherein the upper surface (241) of said flange comprises at least one circumferential transverse fixing section (7), said fixing section extending transversely to the plane (P),

- introducing an opening device (5) inside the capsule body (2), - attaching a bottom membrane (4) inside the capsule body and above the opening device (5),

- filling the capsule body with beverage ingredient,

- fixing a top membrane (3) to the upper surface of the flange (24) of the capsule body by applying heat to the top membrane positioned along the flange with a heating die, wherein the heating die presents a shape complementary to the transverse fixing section (7) of the flange and heats and presses the top membrane in the at least one transverse fixing section of the capsule.