The invention relates to a capsule for use in a device for preparing beverages. The invention further relates to a method for manufacturing a capsule according to the invention. The invention also relates to an assembly of such a capsule and a device for preparing beverages.

Diverse capsules for use in a device for preparing beverages are known in the prior art. A known capsule, as described for instance in EP 0512468, comprises a substantially frustoconical housing consisting of a peripheral wall, an end supply surface connecting to the peripheral wall and an engaging edge connected to the peripheral wall laterally relative to the peripheral wall for the purpose of clamping the capsule in a capsule holder of the device for preparing beverages. The engaging edge is connected to a perforable foil which also forms the discharge side of the capsule. The housing is filled with a substance for extraction, such as ground coffee beans. This known capsule can be placed in a device for preparing a beverage. The capsule is placed for this purpose in a capsule holder which subsequently clamps the capsule, whereby the supply side of the capsule is perforated. Heated water will then be guided at relatively high pressure (6-20 bar) via the supply side into the capsule in the capsule holder, where the water will come into contact with the substance and form the final beverage. Owing to the pressure buildup in the capsule the foil will bulge outward such that the foil will be perforated by the capsule holder, as a result of which the formed beverage can leave the capsule. The housing of the capsule described in the above stated patent is manufactured from aluminium. Aluminium does however have a relatively high cost price, and the processing of aluminium is moreover more difficult and more expensive than if plastic is applied for manufacture of the capsule. There is therefore a growing need to manufacture the housing of the capsule increasingly from plastic. A suitable method of manufacturing plastic capsule housings relatively quickly and inexpensively is thermoforming. It is however found relatively difficult when applying different (thermo)forming steps to keep the wall thickness of the housing constant and homogeneous, which can result in problems during use of the capsule in the capsule holder of a device for preparing beverages. Variations in the dimensioning of the engaging edge can result in it not being possible, or hardly so, to clamp the capsule in the capsule holder and in leakages occurring between the capsule and the capsule holder, which is undesirable. Because a general aim here is a maximum capsule volume, variations in the dimensioning of the peripheral wall can result relatively quickly in the capsule becoming jammed in the capsule holder because the external diameter of at least a part of the peripheral wall is larger than the internal diameter of the capsule holder, this likewise being undesirable. There is therefore a need for an improved capsule with a housing which is at least partially manufactured from plastic and which can be manufactured with a relatively homogeneous wall thickness. An object of the invention is to provide an improved capsule and a method for manufacturing an improved capsule which can fulfil the above stated need.

The invention provides for this purpose a capsule of the type stated in the preamble, comprising: a housing which is manufactured at least partially from plastic and which is at least partially filled with a substance to be extracted and/or dissolved, such as ground coffee, for preparing a beverage, which housing is provided with a supply side for guiding a liquid such as water into the capsule, and with a discharge side located a distance from the supply side for discharging liquid provided with extract and/or dissolved substance and guided through the capsule, wherein the housing comprises: a peripheral wall, an end surface connected to the peripheral wall, and a laterally protruding engaging edge connected at a distance from the end surface to the peripheral wall for the purpose of enabling clamping of the capsule in a capsule holder of a device for preparing beverages; and at least one closing element connected to the laterally protruding engaging edge for enclosing the substance in the housing, wherein at least one side of the peripheral wall is provided with at least one peripheral groove. It has been found that, by applying at least one peripheral groove in the peripheral wall, a deformed, weakened part of the peripheral wall is created which in fact functions during thermoforming of the housing as buffer zone to which excess material of the housing can flow. During the thermoforming the laterally protruding engaging edge is generally formed (pressed) after the peripheral wall and the end surface have been formed. If (excess) heated plastic material were to flow in the direction of the peripheral wall during forming of the engaging edge under pressure, this material will then collect and accumulate at the location of the at least one peripheral groove, and will flow no further than this peripheral groove. By positioning the peripheral groove relatively close to the engaging edge it is thus possible to prevent the wall thickness of at least a substantial part of the peripheral wall being manipulated during forming of the engaging edge, whereby the wall thickness of at least a substantial part of the peripheral wall can be kept substantially constant and homogeneous. It is also the case that during forming of the peripheral wall and the end surface, usually during one sub-step, excess material might begin to flow in the direction of the engaging edge, wherein this material can also be collected in the peripheral groove. The peripheral groove functions in fact as barrier absorption zone for flowing plastic wanting to displace during the production process of the housing from the peripheral edge to the engaging edge, and vice versa. Flowing material will accumulate here in the peripheral groove, which can narrow and/or further deform the peripheral groove, whereby the wall thickness of adjacent parts of the peripheral wall can be kept as uniform as possible. The peripheral groove will generally be arranged in an outer side of the peripheral wall, this generally being most advantageous from a practical viewpoint and in specific preferred embodiments. It is however also possible to envisage the peripheral groove being arranged on an inner side of the peripheral wall. Reference will be made below particularly to the external peripheral groove; most of these embodiments can however also be realized with an internal peripheral groove instead of an external peripheral groove. During arranging of the peripheral groove an annular protrusion (peripheral edge) will generally be formed on an opposite side of the peripheral wall. By applying the at least one peripheral groove it is possible in reproducible manner and much more homogeneously than heretofore to manufacture the wall thickness of the engaging edge and the wall thickness of at least a part of the peripheral wall lying on a side of the peripheral groove remote from the engaging edge, irrespective of possible variations in the thickness of the plastic-comprising starting material that is being applied for manufacture of the housing, this considerably enhancing correct and reliable co-action of the final capsule with a capsule holder of a device. The depth of the peripheral groove preferably lies between 0.2 and 0.6 mm, and more preferably amounts to 0.3 mm. A peripheral groove of such a depth is sufficiently deep to be able to serve as flow barrier during

thermoforming, and is sufficiently shallow to be able to retain, with a minimum wall thickness, the strength of the peripheral wall of the housing.

A single peripheral groove will generally be sufficient to realize a substantially homogeneous wall thickness of the housing during the production process, particularly during thermoforming. It is however also possible to envisage applying a plurality of peripheral grooves which are preferably oriented concentrically of each other. This could further enhance the final dimensioning of the housing, but generally results particularly in a greater stiffness and therefore in a greater form-stability (rigidity) of the housing, whereby deformation of the capsule is countered, this enhancing the final use of the capsule in the capsule holder. The housing usually comprises polypropylene (PP) which is relatively inexpensive and relatively easy to process. The housing preferably comprises a laminate of material layers, wherein at least one material layer is manufactured from PP and at least one other material layer is manufactured from ethylene vinyl alcohol (EVOH). The EVOH layer functions here particularly as barrier layer. The end surface of the housing generally takes an initially sealed (medium-tight) form. It is also possible to envisage the end surface being initially provided with perforations, whereby the end surface acquires a filtering action. The end surface can form the supply side of the housing and the closing element can form the discharge side of the housing, or vice versa. The substantially rigid housing is generally partially or wholly filled with an extractable or soluble food product such as tea, instant soup, coffee, instant hot chocolate and so on.

The shaping and dimensioning of the housing is preferably adapted as far as possible to the shaping and dimensioning of the capsule holder, whereby the capsule will be received substantially form-fittingly in the capsule holder. The advantage hereof is that the internal volume of the capsule can be maximized, this enhancing the quality of the beverage to be prepared. Since many usual capsule holders comprise a frustoconical (tapering) inner wall, it is advantageous for an outer side of the housing, in particular the peripheral wall, to also have a substantially frustoconical shape.

In a preferred embodiment the distance between the at least one peripheral groove and the end surface is greater than the distance between the at least one peripheral groove and the laterally protruding engaging edge. The result hereof is that the peripheral groove is positioned closer to the engaging edge than to the end surface. This positioning of the peripheral groove is usually favourable in that a relatively large part of the peripheral wall can in this way be separated from the engaging edge by the peripheral groove, this being favourable from a quality viewpoint. The closing element can be formed by a rigid plate which is optionally provided with perforations and can thereby function as filter. The closing element will however generally comprise at least one foil. The foil can already be provided here before use with perforations having a size such that liquid can be allowed through and solid parts held back. The foil thus has a filtering action in this case. Such a filter foil need not necessarily be perforated in the capsule holder and can also be positioned such that the filter foil remains intact. When the filter foil remains intact, it is possible to envisage applying a relatively thick and therefore strong and relatively rigid foil with a thickness of for instance 0.5-3 mm. The foil generally comprises an aluminium layer which is optionally provided on one or two sides with a PP layer in order to facilitate one or two- sided adhesion of the foil. It is also possible to envisage the foil comprising aluminium oxide (ALOX), optionally laminated with plastic such as polyethylene terephthalate (PET), whereby an exceptionally thin foil can be obtained with a thickness in the order of magnitude of several microns. The foil is generally connected by means of welding and/or adhesion to the engaging edge, in particular to a flange forming part of the housing.

The foil can also be adapted for substantially medium-tight sealing of the housing of the capsule. The foil will have to be perforated here during use in the capsule holder to enable inflow and/or outflow of liquid. It is favourable here to apply thinner foils with a thickness in the order of magnitude of microns. In a preferred embodiment the capsule comprises a perforation structure coupled substantially rigidly to the housing and/or the foil and provided with at least one perforation element facing toward the foil for perforating the foil, which perforation structure is positioned substantially on a side of the foil remote from the housing, wherein perforation of the foil is caused by deformation of the foil during pressing of the liquid through the capsule. By providing the capsule with its own perforation structure for perforating the foil a conventional perforation plate forming part of the device is no longer required. The advantage hereof is that the prepared beverage need no longer be pressed through the conventional perforation plate of the device, but can optionally be delivered directly from the capsule to a drinking cup. This can drastically reduce the beverage residue left behind in the device, this being advantageous from a hygiene viewpoint and reducing the required maintenance on the device. It is moreover possible in this way to prevent, or at least counter, beverage pressed out of the capsule mixing with beverage residues coming from one or more already used capsules and already present in the device, whereby the taste of the beverage to be prepared can be guaranteed as fully as possible. The perforation structure will be connected substantially rigidly (non-displaceably) to the housing, whereby the external dimensioning of the capsule must generally be smaller than or the same as a volume enclosed by the capsule holder. The perforation structure will generally be provided with one or more throughflow channels or throughfeed openings extending between a side of the perforation structure facing toward the foil and a side of the perforation structure remote from the foil. The particular advantage here is that the number of throughflow channels to be applied and the dimensioning of these throughflow channels can be wholly adapted to the nature of the beverage to be prepared, wherein the intensity of the aeration, the extent of the pressure buildup and the swirling of the beverage pressed out of the capsule can be regulated, which can considerably enhance the taste sensation during consumption of the beverage. Because the foil will be perforated by the generally pointed perforation elements and will be pressed during use against the perforation structure, a filtering action will be realized, whereby solid constituents such as coffee dregs can be kept in the housing. In order to increase the shelf-life of the capsule initial, substantially hermetic sealing of the capsule is generally recommended, wherein the capsule can optionally be filled with an inert gas, such as nitrogen or carbon dioxide in order to further increase the shelf-life of the substance. The result hereof is that a slight overpressure of several hundred millibar will generally be present in the capsule. This overpressure can possibly increase to some extent if coffee powder, which naturally generates a limited amount of gas, is received in the capsule. The perforation structure usually takes a plate-like form in order to limit the volume taken up by the capsule. The perforation structure is preferably positioned at least partially in a volume enclosed by the housing. The advantage hereof is that the dimensioning of the housing need not be adapted to the standard dimensioning of a capsule and capsule holder, this being advantageous from an economic point of view. It is advantageous here for the perforation structure to connect substantially seamlessly to the engaging edge, wherein the perforation structure can even form an integral part of or be integrally connected to at least a part of the engaging edge. It is a further advantage that a side of the perforation structure remote from the foil and a side of the engaging edge are located in the same plane, so that a completely flat underside of the capsule can in fact be realized. The housing and the perforation structure are generally positioned initially on either side of a plane defined by (a central part of) the foil. A suitable material for a perforation structure is plastic, such as for instance PP or polyethylene (PE).

The engaging edge generally comprises at least one flange connected integrally to the housing. It is also possible to envisage the flange being chemically and/or mechanically connected to an inner side and/or outer side of the housing. The engaging edge will usually be constructed in laminated manner from at least one flange forming part of the housing and a support structure coupled to the flange, the support structure being optionally integrally connected to the perforation structure. An edge periphery of the perforation structure is optionally connected via at least one connecting element to the engaging edge. The support structure will generally take a substantially annular form here, because the flange will usually have the same shape. It is possible here to envisage the support structure at least partially enclosing, and even being able to clamp, the flange. It is also possible to envisage welding and/or adhering the support structure to the flange, usually with interposing of the foil. The support structure can be constructed from a plurality of parts which are mutually connected during the production process, for instance by means of welding or adhesion.

The perforation structure and the support structure are preferably manufactured at least partially from the same material, such as polypropylene, in order to enable realization of a reliable mutual connection. As already stated, it is also possible to envisage the perforation structure and the support structure being integrally connected to each other and being manufactured in the same production step, for instance by means of injection moulding. The support structure can in fact be deemed here as an (integral) extension of the perforation structure. The support structure is preferably constructed here from a lower part initially connected directly to the perforation plate and an upper part connected to the lower part, wherein the lower part and the upper part are at least positioned at least partially on either side of the flange connected to the housing or forming part of the housing, whereby the flange is at least partially covered on an underside and an upper side by the support structure. The upper part of the support structure can be connected integrally to the lower part of the support structure, wherein the support structure is even manufactured from one material, in particular plastic, preferably polypropylene. The lower part of the support structure will however generally be adapted to initially hold (support) the perforation structure and the upper part of the support structure will generally be adapted as sealing element manufactured at least partially from thermoplastic polyolefin (TPO). The advantage of a TPO is that a reliable sealing of the capsule in the capsule holder can be realized by means of such a material, wherein a reliable connection can moreover be realized between the lower part of the support structure and the upper part of the support structure.

Instead of connecting the perforation structure rigidly to the housing and/or the foil, it is also possible to envisage the capsule comprising a perforation structure coupled to the housing and provided with at least one perforation element facing toward the foil, this perforation structure being positioned substantially on a side of the foil remote from the housing, wherein the perforation structure is displaceable from a first position, in which the foil is substantially intact, to a second position in which the at least one perforation element perforates the foil, whereby discharge of liquid from the capsule is possible. Displacement of the perforation structure is generally realized by having the capsule clamped by a capsule holder of a device for preparing beverages, a conventional perforation plate forming part of the device no longer being required. In an embodiment the perforation structure is initially connected in the first position via at least one breakable connection to the engaging edge, wherein the perforation structure is displaceable to the second position by breaking the connection between the perforation structure and the engaging edge. In this embodiment the perforation structure will generally take a substantially rigid form. A suitable material for manufacturing such a substantially rigid perforation structure is for instance PP. The perforation structure is preferably initially positioned such that the connection between the engaging edge and the perforation structure will be broken during clamping of the capsule in the device. It is optionally also possible to envisage the connection being broken by the user him/herself by pushing the perforation structure in the direction of the foil. Instead of using a breakable connection it is also possible to envisage providing the engaging edge and/or the housing with a guide for co-action with the perforation structure, whereby the perforation structure can in fact be shifted from the first position to the second position.

In an advantageous embodiment the perforation structure is provided with a plurality of throughflow channels for discharge of liquid, the throughflow channels extending from a side of the perforation structure facing toward the foil to a side of the perforation structure remote from the foil. The perforation structure is generally also provided with a plurality of perforation elements. It is possible here to envisage at least a number of throughflow channels being located at a distance from the perforation elements. It is however also possible to envisage, and even advantageous, for at least one perforation element to be provided with one or more throughflow channels. It is found particularly advantageous in practice to apply a conical perforation element through which extend three throughflow channels which debouch in the cone wall, whereby blocking of the throughflow channels by perforated foil parts can be prevented.

For the purpose of being able to prevent blocking of an outer end of a throughflow channel by the device it is advantageous for a side of the perforation structure remote from the foil to be provided with at least one surface groove, the surface groove connecting to at least one outer end of at least one throughflow channel. It is further possible to envisage a side of the perforation structure remote from the foil being provided with a plurality of surface grooves, the surface grooves connecting the outer ends of the throughflow channels to each other. The surface grooves can connect to each other and intersect each other and in this way form a network. The perforation elements must be sufficiently sharp to be able to perforate the foil. It is therefore advantageous that at least a number of perforation elements take a pointed, in particular pyramid-shaped and/or cone-shaped form. A cone-shaped (conical) shape is generally recommended above a pyramid-shaped embodiment, since the conical embodiment has a periphery varying less pronouncedly as seen in the height of the perforation elements, whereby the foil will tear and/or deform more gradually and therefore more easily.

An edge part of the perforation structure facing toward the foil is generally provided with one or more perforation elements for realizing an edge perforation of the foil. The perforation element can here form a cutting edge which can extend over the whole or partial edge part of the perforation structure. In addition, it is possible to envisage application of more centrally positioned perforation elements. In order to be able to guarantee a reliable perforation, it is generally advantageous that the foil initially engages under bias on at least one perforation element. This is because sufficient pressure buildup in the housing of the capsule will, as a result of the bias, result relatively quickly in perforation of the foil.

In an advantageous embodiment of the capsule a side of the perforation structure remote from the foil is provided with an upright sealing edge which protrudes in a direction away from the foil. This upright sealing edge provides on the one hand for an improved connection of the capsule to the device, and thereby for an improved sealing. The application of the upright sealing edge moreover makes the perforation structure stackable (nestable) with another perforation structure, this being particularly advantageous during the production process.

In a preferred embodiment the internal peripheral wall of the housing is adapted as stop edge for the perforation structure situated in the second position. By having the displacement of the perforation structure from the first position to the second position (also) bounded by the internal stop edge of the housing an improved edge sealing can be obtained between the peripheral side of the engaging edge and an inner wall of the housing, this enhancing operation of the capsule. The perforation structure can here engage directly on the peripheral edge, or indirectly, generally with interposing of the foil.

The capsule preferably comprises at least one sealing element connecting to an outer side of the housing, the sealing element being adapted to seal a space between the capsule holder and the housing during clamping of the capsule in the capsule holder. The sealing element can be manufactured here from a plastically deformable material such as metal. The sealing element is however preferably manufactured from a resilient material, in particular an elastomer. The capsule can also comprise one or more sealing elements. When the capsule comprises a plurality of sealing elements, it is then possible to envisage the sealing elements engaging on each other and optionally being connected to each other, in particular by means of a welded connection. It is however also possible here for the sealing elements to be positioned a distance from each other, whereby a multiple sealing is realized during the extraction process of the capsule placed and clamped in a capsule holder. The one or more sealing elements will generally be positioned on an outer side (i.e. a side facing toward the device) of the housing. As already stated, the at least one sealing element is preferably at least partially manufactured from a thermoplastic polyolefin (TPO). The advantage of a TPO is that a TPO is also flexible but, in contrast to a rubber elastomer, comprises relatively few cross-links, whereby a TPO softens considerably more at increased temperature (welding temperature) than a rubber elastomer which is of thermosetting character and does not soften, or hardly so, due to a large number of cross-links. This more intensive softening enables better fusing of the sealing element with another part of the capsule during a (thermal or ultrasonic) welding process, whereby the forming of gaps between the sealing element and another part of the capsule can be prevented, this enhancing the eventual extraction process. It is particularly advantageous here for the capsule part to which the sealing element is connected to be manufactured from plastic, and preferably a polyolefin such as polypropylene, which enhances the mutual fusing during welding, and therefore the mutual adhesion of the two components. Welding is otherwise preferred to adhesion, since no additional adhesive means are required, this being particularly advantageous from an economic and logistic viewpoint and from the viewpoint of environmental-friendliness. A further advantage of applying a TPO is that manufacture of a TPO is quicker and easier than that of a thermosetting elastomer (rubber elastomer) which is manufactured in three lengthy steps (mixing, injection moulding and cross-linking). Other than thermosetting polymers, TPOs can moreover be wholly or partially recycled, this being particularly advantageous from the viewpoint of environmental-friendliness. The TPO from which the sealing element is at least partially manufactured preferably comprises polypropylene. Since the housing and/or a part of the foil facing toward the sealing element is generally also manufactured from polypropylene, an excellent welded connection can be realized between the sealing element on the one hand and the housing and/or the foil on the other. The sealing element more preferably comprises a composition of polyolefins, the composition comprising: polypropylene and an elastomeric copolymer comprising units of ethylene and units of an V-olefin. The V-olefin is more preferably formed here by ethylene, propylene or 1 -butene. In a particular preferred embodiment the TPO is formed by a polyolefin composition, comprising: A) 20 to 50 parts by weight of a crystalline polypropylene polymer with an isotacticity index higher than 80 which is selected from a polypropylene homopolymer and polypropylene copolymers comprising 0.5 to 15 mol% ethylene and/or an V-olefin with 4 to 10 carbon atoms, wherein the

polypropylene polymer has a molecular weight distribution (MWD) greater than 3.5; and B) 50 to 80 parts by weight of an elastomeric ethylene copolymer with olefins CH ₂ =CHR, wherein R is an alkyl with 1 to 10 carbon atoms, which optionally comprises minor quantities of units derived from a polyene, wherein the copolymer comprises 40 to 70% by weight of units derived from ethylene and 30 to 60% by weight of units derived from an V-olefin, and has the following characteristics: a) a molecular weight distribution of less than 3.5, b) a crystallinity content, expressed as the enthalpy of fusion, lower than 20 J/g and c) a content of 2-1 regio-inversions of the V-olefin units lower than 5%. Further advantageous embodiments are described in EP 0770106, the content of which forms part of this patent specification by way of reference. In another particular preferred embodiment the TPO is formed by a polyolefin composition, comprising: A) 10-50 parts by weight of a homopolymer of polypropylene with an isotactic index higher than 80 or a copolymer of polypropylene with ethylene, a CH ₂ =CHR V-olefin, wherein R is an alkyl group with 2-8 carbon atoms, or a combination thereof, the copolymer comprising more than 85% by weight

polypropylene; B) 5-20 parts by weight of a copolymer fraction comprising ethylene, insoluble in xylene at ambient temperature; C) 40-80% by weight of a copolymer fraction of ethylene and polypropylene or another CH ₂ =CHR V-olefin, wherein R is an alkyl group with 2-8 carbon atoms, or combination thereof with optionally a small quantity of diene which comprises less than 40% by weight ethylene, which fraction is soluble in xylene at ambient temperature and with an intrinsic viscosity of 1.5-4 dl/g; wherein the percentage by weight of the sum of the (B) and (C) fractions in respect of the overall polyolefin composition is 50-90% and the weight ratio(B)/(C) is lower than 0.4, the polyolefin composition being obtainable by applying a polymerization catalyst comprising the reaction product of a solid component comprising a titanium compound and an electron donor compound supporting on magnesium chloride, with an Al trialkyl compound and an electron donor compound. Further advantageous embodiments are described in EP 0472946, the content of which forms part of this patent specification by way of reference. Examples of commercially available TPOs are Hifax ^® , in particular Hifax ^® 7334 XEP, Adflex ^® , in particular Adflex ^® X500F, and Softell ^® obtainable via LyondellBasell. It is otherwise also possible to envisage further providing an outer surface of the capsule with at least one other type of sealing element for the purpose of sealing the capsule in the device. The sealing element can thus connect to the laterally protruding engaging edge and/or to the peripheral wall, whereby a sealing element of L-shaped cross-section is applied. The sealing element optionally lies against the end surface of the housing. The at least one peripheral groove is preferably located a distance from the at least one sealing element, this generally facilitating medium-tight attachment of the sealing element to the housing. In a preferred embodiment the sealing element encloses at least a part of at least one absorption cavity. Applying a resilient sealing element which at least partially encloses one or more absorption cavities imparts to the sealing element an improved capacity for deforming during clamping of the capsule in the capsule holder. The absorption cavity facilitates deformation, as a consequence of which the sealing element can curve more easily round a clamping edge of the capsule holder, whereby the sealing element in fact engages around the clamping edge on one or two sides, depending on the shape of the sealing element. This engagement round the clamping edge of the capsule holder by the sealing element of the capsule improves the sealing capacity of the sealing element, and thereby of the capsule, in significant manner and makes the sealing capacity considerably less dependent on the shape of the clamping edge of the capsule holder. The absorption cavity therefore functions as cushion and as (temporary) receiving space (absorption space) for the resilient material as soon as a load is exerted on the sealing element. The absorption cavity is filled with a substance other than the resilient material from which the sealing element is substantially manufactured. The absorption cavity will generally be filled with air, liquid and/or gel. For the purpose of realizing a desired deformation of the sealing element it is possible to envisage the sealing element being provided with at least one weakening zone, a variable wall thickness and/or a particular shape, whereby the desired deformation can already be predetermined.

It is possible to envisage at least one absorption cavity being substantially wholly enclosed by the sealing element and the housing. It is also possible to envisage at least one absorption cavity being substantially wholly enclosed by the sealing element itself. The absorption cavity can here take a substantially closed (airtight or liquid-tight) form, wherein no exchange is possible between the content of the absorption cavity and the ambient atmosphere, whereby a closed cushion is formed. The closed absorption cavity will generally be filled here with air or another gas. It is also possible to envisage a liquid, in particular water, or a gel being applied as filling for the absorption cavity/cavities. In an alternative embodiment of the absorption cavity the absorption takes an open form, whereby communication is possible between the content of the absorption cavity and the ambient atmosphere. In this latter embodiment the absorption cavity will generally be filled with air. When the sealing element is loaded, the air will be at least partially pressed out of the absorption cavity, this facilitating deformation of the sealing element.

The absorption cavity can be formed by an elongate groove, and in particular extends annularly. The shape of the absorption cavity hereby follows the shape of the sealing element as such. It is also possible to envisage the absorption cavity being given a bubble-like form. When a plurality of open, bubble-like absorption cavities are applied, and particularly wherein they are mutually connected, a resilient porous structure is in fact formed in the sealing element. In addition to the use of one or more absorption cavities, it is also possible to envisage a side of the sealing element remote from the engaging edge being provided with at least one protruding edge. The protruding edge here forms a dam (barrier) enabling further prevention of liquid leakage from the capsule holder. The edge preferably has an annular shape here and follows the shape of the sealing element as such. It is possible to envisage a side of the sealing element remote from the engaging edge being provided with a plurality of protruding edges. The edges are preferably oriented concentrically relative to each other.

In an embodiment of the capsule the at least one sealing element is arranged releasably round the housing and/or is connected releasably to the engaging edge and/or the housing, whereby it is not necessary to modify the production lines for the capsules, this being particularly advantageous from an economic viewpoint. The type, in particular the thickness, of the sealing element to be applied can moreover be adapted to the (most likely) device in which the capsule is going to be used. The arranging of the sealing element can take place by machine during the production process. It is however also possible to envisage this arrangement taking place manually, optionally by the consumer him/herself, whereby he/she can have the type of sealing element to be applied depend on the type of device (coffee machine) the consumer in question is using. A further advantage of the sealing element is that the choice of material and shape can be optimized in relatively simple manner for the purpose of realizing a liquid- tight, in particular medium-tight, seal during the preparation process. The sealing element arranged releasably round the housing will generally exert a bias on an outer side of the housing, whereby undesirable removal of the sealing element from the housing can be countered as far as possible. It is also possible to envisage having the sealing element held by the engaging edge and/or the housing, for instance by applying holding elements such as hooks or other locking protrusions.

The sealing element will however generally be connected non-releasably to the engaging edge and/or the housing. This connection will then preferably be realized by means of welding. The sealing element as described in one or more of said embodiment variants in this patent specification can also be applied in advantageous manner in a capsule as according to claim 1 without the capsule being provided with one or more peripheral grooves.

The invention also relates to a housing for use in a capsule according to the invention, wherein at least one peripheral groove is arranged in an outer side of the housing. The housing is manufactured here at least partially from plastic. The housing is preferably formed by means of thermoforming. Advantages and embodiment variants of the housing according to the invention have already been described at length in the foregoing.

The invention further relates to a method for manufacturing a capsule for preparing beverages, in particular a capsule according to the invention, comprising the steps of: A) forming a housing of the capsule by means of thermoforming by deforming a material layer at least partially manufactured from plastic, wherein during step A) at least the sub-steps are performed of: Al) forming a peripheral wall and an end surface of the capsule, A2) arranging at least one peripheral groove in the formed peripheral wall, and A3) forming an engaging edge protruding laterally relative to the peripheral wall; B) at least partially filling the housing with a substance to be extracted and/or dissolved, such as ground coffee, for the purpose of preparing a beverage; and C) enclosing the substance in the housing by connecting a closing element to the laterally protruding engaging edge. Step A) could be performed separately, optionally at a different location, relative to steps B) and C). Step A) will be performed at increased temperature, wherein the plastic material layer has softened and is therefore more easily deformable. A typical temperature for the thermoforming according to step A) lies between 230 and 320 degrees Celsius. The material layer will usually already be preheated to a typical temperature of between 100 and 150 degrees Celsius before step A) is performed. Sub- step Al) will usually be performed by means of vacuum-forming, wherein the material layer is drawn as a result of underpressure in a mould. Sub-step A2) preferably takes place by means of at least one shaping element which exerts a pressure, directed toward the centre of the housing, on at least one peripheral part of an outer side of the peripheral wall and forms the at least one peripheral groove. In sub-step A3) the engaging edge is generally formed by means of shaping and pressing. The thickness of the material layer used is generally about 1 mm. By stretching and deforming the material layer during step A) the thickness of the final housing will usually lie between 200 and 500 micron. The material layer generally comprises a laminate of one or more PP layers and one or more EVOH layers.

In a preferred embodiment the method comprises step D), comprising of removing the formed housing from a remaining part of the material layer. The housing can be removed here from a remaining part of the material layer by means of cutting or punching. This separation of the housing relative to a remaining part of the material layer preferably takes place before filling of the capsule according to step B). It is however also possible to envisage this separation taking place only after step B) or even after step C).

During sub-step A2) at least one peripheral edge is preferably formed on an inner side of the peripheral wall during forming of the at least one peripheral groove. This internal peripheral edge can generally be advantageously used as stop edge for a perforation structure (if applied) of the capsule.

The invention also relates to an assembly of a capsule according to the invention and a device for preparing beverages, which device comprises a capsule holder for receiving the capsule. The capsule holder will here generally comprise a plurality of holder parts which are mutually displaceable between an opened state, in which the capsule can be placed in the capsule holder, and a closed state in which the engaging edge and the sealing element of the capsule are clamped substantially liquid-tightly by the holder parts.

The invention further relates to the use of a capsule according to the invention in a device for preparing beverages.

The invention will be elucidated on the basis of non-limitative exemplary embodiments shown in the following figures. Herein:

figures la- Id show different views of a capsule according to the invention,

figures 2a and 2b show different views of the capsule according to figure 1 and a capsule holder of a device for preparing beverages enclosing the capsule,

figures 3a and 3b shows different views of another capsule, or at least a part thereof, according to the invention, and

figure 4 shows a detailed cross-section of a part of another capsule according to the invention.

Figures la and lb show different perspective views of a capsule 101 according to the invention, and figure lc shows a side view of the same capsule 101. Capsule 101 comprises for this purpose a substantially frustoconical (truncated conical) housing 102 at least partially filled with a substance to be extracted and/or dissolved, such as ground coffee, tea, cocoa, milk powder and so on. Housing 102 comprises a perforable upper wall 103 which forms an end supply surface of capsule 101. The upper wall will be perforated in a capsule holder of a device for preparing beverages, after which water, in practice generally a mixture of water and air, is pressed into capsule 101 at a pressure of between 1 and 20 bar. Housing 102 also comprises a peripheral wall 104 (side wall) which is integrally connected to upper wall 103 and which tapers to some extent in the direction of upper wall 103, wherein in the shown situation peripheral wall 104 encloses an angle with the vertical lying between 5° and 7°, this angle of inclination

corresponding to the complementary angle of inclination of a number of capsule holders available on the market, whereby the volume of housing 102 can generally be maximized. Peripheral wall 104 is provided with a ridge 105 to enable better fitting of capsule 101 on many of the known capsule holders. Housing 102 further comprises a plurality of strengthening elements 106 arranged recessed into upper wall 103 and/or peripheral wall 104. Strengthening elements 106 resist deformation of housing 102 as much as possible during use. Housing 102 further comprises a flange 107 which is integrally connected to the peripheral wall (see figure Id) and which functions as laterally protruding engaging edge to allow clamping of capsule 101 in the capsule holder. An inner edge of flange 107 does in fact define (a part of) the discharge side of capsule 101 , this discharge side being initially sealed substantially medium-tightly by a foil 108 connected to flange 107. The connection between flange 107 and foil 108 is preferably realized by means of (ultrasonic) heat welding, whereby a relatively reliable connection can be realized between flange 107 and foil 108. It is advantageous here for the contact surfaces for fusing together to be manufactured from the same material, such as PP. Flange 107 is clamped by and/or enclosed by and/or connected to a support structure 109 for a plate-like perforation structure 1 10. In this exemplary embodiment support structure 109 has a modular construction of an upper part, formed by a sealing element 109a, and a lower part, formed by a holding element 109b, connected, preferably welded, to sealing element 109a for initially holding the perforation structure 1 10. Sealing element 109a of support structure 109 is adapted to seal capsule 101 in a capsule holder (see figure 2b), while lower part 109b of support structure 109 is in principle adapted to initially hold perforation structure 110. Sealing element 109a and holding element 109b can optionally be connected as separate elements to flange 107. Perforation structure 1 10 is connected by means of a plurality of breakable connecting elements 1 1 1 to support structure 109. As shown, housing 102 and perforation structure 1 10 are positioned on opposite sides of foil 108. In this exemplary embodiment, as shown in the cross-sections of figures 2a and 2b, perforation structure 1 10 comprises a plurality of peripherally oriented ('peripheral') perforation elements 1 12 and a plurality of more centrally oriented ('central') perforation elements 1 13. All perforation elements 1 12, 1 13 have a pointed outer end directed toward foil 108 and are adapted to perforate foil 108. Most of the central perforation elements 1 13 are moreover each provided with three throughflow channels 1 15 extending from an upper side of perforation structure 1 10 to an underside of perforation structure 110 in order to enable discharge of water enriched with the substance in capsule 101 , i.e. the prepared beverage. As shown in figure Id, all perforation elements 1 12, 1 13 protrude equally far, whereby the outer ends of perforation elements 1 12, 1 13 form a virtual plane. In the shown initial situation foil 108 engages on substantially all perforation elements 1 12, 113, such however that foil

108 remains intact (closed). By breaking the connections 1 11 between support structure

109 and perforation structure 1 10 the perforation structure 1 10 can be displaced from an initial position (first position (figure Id)) to a higher position (second position (figures 2a and 2b)) in which perforation structure 1 10 at least partially perforates foil 108, whereby the discharge side of capsule 101 is in fact opened, and wherein perforation structure 1 10 comes to lie at least partially in a space enclosed by housing 102.

Breaking the connections 11 1 can be realized by a user him/herself, but will in practice generally be realized in the capsule holder during closing of the capsule holder, and thereby clamping of capsule 101.

During clamping of capsule 101 in the capsule holder the breakable connection between support structure 109 and perforation structure 1 10 will in practice generally be broken and perforation structure 1 10 will be pushed in the direction of foil 108, whereby perforation elements 1 12, 1 13 will pre-perforate foil 108. The assembly of perforated foil 108 and perforation structure 1 10 will act here as filter, wherein beverage will be allowed through and solid parts, in particular residue, will be held back.

Particularly engaging edge 109 of capsule 101 is clamped during the clamping in order to realize a seal between capsule 101 and the capsule holder. A special sealing element 109a is applied in the shown capsule 101 according to the invention. Sealing element 109a is of resilient nature and is provided with three annular absorption cavities 1 16 (see figure Id). Absorption cavities 1 16 are further bounded here by flange 107. Sealing element 109a further encloses a further annular corner cavity 1 17, this corner cavity 1 17 being further bounded by flange 107 and peripheral wall 104 of housing 102. All cavities 1 16, 1 17 are adapted to facilitate deformation of sealing element 109a, whereby sealing element 109a can be pressed in simpler and better manner against the capsule holder, this enhancing the mutual sealing (see figure 2b). In the shown embodiment sealing element 109a is not connected to an upper side of flange 107, whereby the formed cavities 1 16, 1 17 can deform relatively easily. An (upper) side 118 of sealing element 109a remote from flange 107 follows the shape of the arcuate absorption cavities 1 16 and therefore takes a profiled form, whereby dam formation occurs which can further improve the sealing. Sealing element 109a is manufactured in this embodiment from a TPO. A reliable seal of the capsule in the capsule holder is realized due to the thermoplastic character of a TPO. Other than conventional thermosetting elastomers (rubber elastomers), thermoplastic polymers are manufactured using equipment suitable for processing resins. Thermoplastic polymers are quicker and easier to manufacture than thermosetting elastomers, which are manufactured in three lengthy steps (mixing, injection moulding and cross-linking). Other than thermosetting polymers, thermoplastic polymers can moreover be fully or partially recycled. Since lower part 109b of support structure 109 is generally manufactured at least partially from PP and ultrasonic welding is recommended to mutually connect holding element 109b and sealing element 109a, it is advantageous for a thermoplastic polypropylene- based elastomer, such as Adflex®, in particular Adflex® X500F, to be applied for the sealing element 109a. In the exemplary embodiment shown in figures la-2b the housing is manufactured by means of thermoforming. Thermoforming, also referred to as vacuum-forming, relates to a non-machining shaping technique wherein a (flat) starting foil is first heated, after which it is plastically deformed to a desired shape. Heating of the starting foil generally takes place using an infrared radiator. This can take place on one or both sides. During the thermoforming the heated starting foil will generally be clamped close to a mould, wherein air is extracted from the mould via discharge channels in the mould. The still plastic material will hereby take on the shape of the mould. The shape can be fixed by means of (forced) cooling. In some situations compressed air is blown against the foil on a side of the heated foil facing away from the mould in order to make the process progress more quickly, and therefore more economically. Peripheral wall 104 and upper wall 103 are formed in the mould. The flange is subsequently formed by deformation and pressing of the starting foil. Particularly during pressing of flange 107 material will generally be pressed in the direction of peripheral wall 104. In order to consolidate the wall thickness of peripheral wall 104 as far as possible, peripheral wall 104 is provided close to flange 107 with a peripheral groove 130, i.e. an annular recess in an outer surface of peripheral wall 104. In this exemplary embodiment peripheral groove 130 has a depth of 0.3 mm. Peripheral groove 130 functions as buffer zone for storage of flowing material so that adjacent parts retain a desired wall thickness. Figure Id shows clearly that arranging an annular peripheral groove 130 on an inner side of peripheral wall 104 during the thermoforming results in a complementary annular protrusion

(internal peripheral edge) 131. After forming of the housing the housing is separated by means of punching from a remaining part of the starting foil. Frequently applied materials in the thermoforming process are: PVC, ABS, PE, PET, PS and PP. A laminate of layers is preferably applied, such as for instance PP-EVOH-PP, PS-EVOH- PE and PP-EVOH-PE.

Figure 2a shows that capsule 101 is situated in an opened capsule holder 1 19 of a device for preparing beverages, in particular coffee. Capsule holder 1 19 here comprises a first holder part 1 19a and a second holder part 1 19b displaceable relative to first holder part 1 19a. First holder part 1 19a comprises one or more cutting elements (not shown) for perforating upper wall 103 of capsule 101. First holder part 119a further comprises a clamping edge 120 for pressing engaging edge 1 14 onto second holder part 119b such that capsule holder 1 19 is substantially completely sealed, whereby leakage of water can be prevented. Second holder part 1 19b is provided with one or more discharge openings 121 for beverage. During closing of capsule holder 119 by displacing first holder part 1 19a and second holder part 1 19b toward each other (see figure 2b) the upper wall 103 of capsule 101 will be perforated, engaging edge 1 14 will be clamped substantially liquid-tightly between the two holder parts 1 19a, 119b and perforation structure 1 10 will moreover be pressed into housing 102, whereby foil 108 will be at least partially perforated and discharge of beverage from capsule 101 is made possible. Perforation structure 1 10 will come to lie here against the annular protrusion 131, whereby an improved internal sealing is realized between perforation structure 110 and peripheral wall 104. The advantage of this pre-perforation, among others, is that a better aeration of capsule 101 is obtained, this generally enhancing both the beverage preparation process and the finally obtained taste of the beverage. During this clamping the sealing element 109a will be clamped and deformed such that sealing element 109a exerts a lateral force on a longitudinal side of first holder part 1 19a, whereby the sealing of capsule 101 in capsule holder 1 19 is improved. As shown in figure 2b, an inner absorption cavity 1 16 is pressed empty here, whereby the other absorption cavities 1 16 swell and engage under bias on the first holder part 1 19a. The air present in these absorption cavities 1 16 can no longer escape because sealing element 109a is fully welded at a peripheral edge to the underlying holding element 109b, whereby the sealing action is maintained.

Figure 3a shows a cross-section of another capsule 201 according to the invention. Capsule 201 comprises for this purpose a substantially frustoconical (truncated conical) housing 202 at least partially filled with a substance to be extracted and/or dissolved, such as ground coffee, tea, cocoa, milk powder and so on. Housing 202 comprises a perforable upper wall 203 which forms an end supply surface of capsule 201. The upper wall will be perforated in a capsule holder of a device for preparing beverages, after which water, in practice generally a mixture of water and air, is pressed into capsule 201 at a pressure of between 1 and 20 bar. Housing 202 also comprises a peripheral wall 204 (side wall) which is integrally connected to upper wall 203 and which tapers to some extent in the direction of upper wall 203, wherein in the shown situation peripheral wall 204 encloses an angle with the vertical lying between 5° and 7°, this angle of inclination corresponding to the complementary angle of inclination of a number of capsule holders available on the market, whereby the volume of housing 202 for receiving for instance coffee can generally be maximized. Peripheral wall 204 is provided with a ridge 205 to enable better fitting of capsule 201 on many of the known capsule holders. Housing 202 further comprises a plurality of strengthening elements 206 arranged recessed into upper wall 203 and/or peripheral wall 204. Strengthening elements 206 resist deformation of housing 202 as much as possible during use. Housing 202 further comprises a flange 207 which is integrally connected to the peripheral wall and which functions as laterally protruding engaging edge to allow clamping of capsule 201 in the capsule holder. An inner edge of flange 207 does in fact define ^; (a part of) the discharge side of capsule 201 , this discharge side being initially sealed substantially medium-tightly by a foil 208 connected to flange 207. The connection between flange 207 and foil 208 is preferably realized by means of (ultrasonic) heat welding, whereby a relatively reliable connection can be realized between flange 207 and foil 208. It is advantageous here for the contact surfaces for fusing together to be manufactured from the same material, such as PP. Flange 207 is clamped by and/or enclosed by and/or connected to a support structure 209 for a plate-like perforation structure 210. In this exemplary embodiment support structure 209 has a modular construction of an upper part, formed by a sealing element 209a, and a lower part, formed by a holding element 209b, connected, preferably welded, to sealing element 209a for initially holding the perforation structure 210.

Sealing element 209a of support structure 209 is adapted to seal capsule 201 in a capsule holder, while lower part 209b of support structure 209 is in principle adapted to initially hold perforation structure 210. Sealing element 209a is welded here to holding element 209b. In order to improve the welded connection the holding element 209b is provided with a protruding ring 21 1, usually referred to as energy ring, and adapted for fusing together of holding element 209b and sealing element 209a. Figure 3b is a detail view of a part of sealing element 209a which shows particularly that sealing element 209a is provided with an upright ring 212, whereby the sealing elements can be easily stacked after manufacture for storage and transport purposes. Sealing element 209a is also provided on an underside with two concentric rings, wherein an outer ring 213a is adapted to be welded to flange 207, and wherein an inner ring 213b generally engages/lies loosely against an upper side of flange 207. Protruding from inner ring 213b is a curved part 214 of sealing element 209a adapted to engage on peripheral wall 204 of capsule 201. Owing to the specific shaping and attachment of sealing element 209a to flange 207 and to holding element 209b two (larger) air chambers (designated with letters A and B) are formed between sealing element 209a and housing 202. The air chambers (A, B) improve the sealing of capsule 201 in a capsule holder, as has also been described in similar manner in the above description of figures ld-2b. Sealing element 209a and holding element 209b can optionally be connected as separate elements to flange 207. Perforation structure 210 has the same construction and operation as perforation structure 110 as shown in figures 1 a-2b and as described in the foregoing. In order to consolidate the wall thickness of peripheral wall 204 as far as possible, peripheral wall 204 is provided close to flange 207 with a peripheral groove 215, i.e. an annular recess in an outer surface of peripheral wall 204. In this exemplary embodiment peripheral groove 215 has a depth of 0.4 mm. Peripheral groove 215 functions as buffer zone for storage of flowing material during the thermoforming of housing 202, so that adjacent parts retain a desired wall thickness. The sealing element 209a shown in figures 3a and 3b can otherwise also be applied in a capsule according to claim 1 of this patent specification (as filed), but without being provided with one or more peripheral grooves 215.

Figure 4 shows a schematic view of a method for manufacturing a capsule according to the invention. Use is made here of a roll (I) provided with plastic starting foil with a thickness of about 1 mm. The starting foil is removed here from the roll using pneumatically driven holding members and the starting foil is guided through a first heating unit (II), where the starting foil is preheated to a temperature of between 100 and 150 degrees Celsius. The starting foil is subsequently guided through a second heating unit (III) for further heating of the starting foil to a desired temperature for thermoforming, this temperature preferably being about 300 degrees Celsius. By then guiding the starting foil over a mould provided with a plurality of mould cavities in which an underpressure is applied, the starting foil will be suctioned against an inner side of each mould cavity (IV). A peripheral wall 104 and an upper side 103 of the housing of the capsule is manufactured here in each mould cavity. Flange 107 of the capsule is formed by means of subsequent pressing, after which the formed housing is cooled and made form-retaining. The quality of the formed housings can be monitored by means of scanning equipment. Following manufacture of the housings, the housings are filled with coffee powder or other substance used for preparing beverages (V), after which the housing is sealed by means of foil (VI) which comprises aluminium and comes from a foil roll and which is welded to flange 107 of the housing (VII) to form the actual capsule 101. Capsules 101 are then removed from the remaining starting material by means of punching (VIII), after which the remaining starting material is rolled up and optionally reused (IX).

It will be apparent that the invention is not limited to the exemplary embodiments shown and described here, but that within the scope of the appended claims numerous variants are possible which will be self-evident to the skilled person in this field.