Capsule for preparing an infusion beverage

Abstract

The invention relates to a capsule (1) for preparing an infusion beverage from the interaction between an infusion product (22) and a liquid, said capsule (1) comprising a capsule body (2) and a lid (4). The capsule body (2) and the lid (4) are mutually connected to one another for creating a closed infusion chamber (6) containing the infusion product (22). The capsule body (2) is made of a capsule body material comprising between 60% to 89.5% w / w of PBS, PBAT, PLA, TPS, PHA, regenerated cellulose or combinations thereof and between 0.5 and 5% w / w, preferably between 0.5 and 2% w / w of at least one catalysator for enhancing the biodegradability of the capsule body (2), said at least one catalysator comprising one among the group of polyphosphate salts, phthalates, epoxides or combinations thereof and finally one or several organic and inorganic fillers respectively between 5 and 25% w / w and 5 and 20% w / w.

Description

Field of the invention

[0001] The invention relates to a capsule for preparing an infusion beverage from the interaction between an infusion product and a liquid, said capsule comprising a capsule body and a lid, said capsule body and said lid being mutually connected to one another for creating a closed infusion chamber containing said infusion product.State of the art

[0002] Preparation of infusion beverages from infusion products, that is beverages such as coffee, tea, chocolate, soup or others, in the form of pre-dosed capsules has become more and more popular in the recent years.

[0003] This way of beverage preparation has some advantages over those beverages prepared from a bulk infusion product. Since the capsules contain one, or maximum two single doses per capsule, the organoleptic properties of the infusion product, are better preserved. This allows the user to prepare beverages with higher quality. Also, the user must not buy such big quantities of infusion product, thus preventing the infusion product from spoiling after the expiration date.

[0004] However, to preserve the organoleptic properties of the infusion product, the capsules, or at least the envelopes thereof are produced with materials which are oxygen and vapour tight. These materials are e.g., aluminium, plastics, or the like. This kind of materials are not environmentally friendly, and it is advisable not to dispose the capsule in the normal litter. On the other hand, these capsules are difficult to recycle because, firstly, the users often do not bring the capsules to the corresponding recycling facilities and if they do, the different components forming the capsule need to be separated to make the correct recycling.

[0005] Due to these difficulties, recently different attempts have been made to produce capsules which are less harming for the environment.

[0006] In this context, capsules made of biodegradable materials have been proposed.

[0007] Document EP3354596A1 discloses a capsule for preparing beverages which after use, results in a reduced environmental load. The capsule comprises a capsule body and a sealing member which is connected to a laterally projecting engagement edge of the capsule body. The capsule body and / or the sealing member comprises at least one barrier layer, which barrier layer is at least partly, and preferably substantially, impermeable to oxygen. The capsule body preferably also comprises at least one material layer surrounding the barrier layer which completely protects the barrier layer from the atmosphere surrounding the capsule. The capsule can be disposed of after use, preferably with the organic waste, following which the capsule is molecularly decomposed in a biological manner by microorganisms, and optionally after supplying activation heat and moisture (water). However, this capsule having a double-layer structure is complicated to produce and cannot avoid the use of the material layer to provide the atmosphere protection.

[0008] Document EP3774595A1 discloses a capsule for preparing a beverage. The capsule comprises a body made from a biodegradable material according to standard EN 13432 and comprising at least one sealing film having at least one layer made of compostable material. Again, the sealing film leads to a composite material capsule which is complicated to produce, and even more complicated to recycle.

[0009] Document EP3617094A1 discloses a capsule for extracting a drink. The capsule comprises a hollow body defining an internal volume for receiving a product to be infused such as coffee. The hollow body comprises a tubular lateral wall with a central axis, and a bottom closing a first axial end of the lateral wall. The body is made of a material chosen from among polyhydroxyalcanoates, and said material optionally further comprising at least one additive.

[0010] Another problem of this type of prior art capsules is that they are often too weak to resist the mechanical and thermal forces originated in the infusion machine.

[0011] In the present invention the terms biodegradability and compostability must be clearly differentiated.

[0012] Biodegradability is an intrinsic characteristic of materials, which are chemically degraded by the action of micro-organisms present in each environment, characterised mainly by temperature, humidity and the organisms present. Other factors may cause degradation or fragmentation of a product, but biodegradation cannot be referred to in such cases.

[0013] Compostability is the characteristic of a final product made of biodegradable materials, which can physically disintegrate within a predetermined period of time without any toxic effect on the environment. In the case of compostability the product is chemically degraded thanks to a controlled environment, via predetermined high temperature and humidity conditions and microorganisms expressly applied to the process.

[0014] Furthermore, under the concept of compostability, also two different procedures depending on the environmental conditions are to be differentiated, which are:a) industrial compostability and b) home compostability.

[0015] Therefore, in the present invention the term a) industrially compostable stands for a capsule fulfilling the biodegradability requirements for packaging recoverable product through composting and biodegradation as described in EU norm EN 13432:2000. Furthermore, the norm EN 14995:2006 provides the details on the evaluation on industrial compostability.

[0016] Both prior art capsules previously described are indeed industrially compostable. Therefore, although these capsules represent a step forward in terms of sustainability of the use of pre-dosed capsules there is still a long way to go to reduce the impact on the environment by these capsules.

[0017] On the other hand, in the present invention, the term b) home compostable or home compost stands for a capsule in which the material so defined undergoes degradation by biological processes producing carbon dioxide, water and organic compounds and biomass. However, in this second case there are currently no international standards specifying the conditions for home composting of biodegradable plastics.

[0018] Due to this, in the present invention the term home composting is applied to a capsule fulfilling the requirements of the "OK Compost Home" mark of the certifying institute TÜV Austria, as detailed in their website https: / / www.tuv-at.be / green-marks / certifications / ok-compost-seedling / , according to the latest update of the site of 18 August 2021 as recorded in the Internet Archive accessible through the so-called "Wayback Machine" (www.archive.org).

[0019] According to this site, the OK Compost Home refers to products that also compost at lower temperatures compared to industrial compost. Therefore, they can go into the compost heap in the garden at home.

[0020] The conditions for home compost are based on the fulfilment of 4 criteria for the product to be considered as a home compostable end product. These criteria must be verified by corresponding tests. These conditions are the following: Biodegradable material: biodegradation test (chemical decomposition, conversion into CO 2 by the action of microorganisms). The chemical decomposition must be greater than 90% within 12 months. Test temperature must be below 30°C. Evidence of degradation must be proven via a test according to UNE-EN ISO 14855-1:2013 and DIN EN ISO 14855:2019. Disintegrable end product: disintegration test (physical, with biowaste) of the end product within 6 months. After this period, 90% of the initial weight of the remaining residues must pass through a 2x2 mm mesh. In addition, there must be no visual contamination of the original material (e.g., no visible metallic or brightly coloured residues, even if they are smaller than 2 mm, but rather colours in black-brown tones like those of the biowaste so that they cannot be distinguished). The test is done for a maximum thickness. Evidence must be demonstrated via a test according to the standard UNE-EN ISO 20200:2016 at temperatures of 25 ± 5 °C. Non-ecotoxic material: compost material quality analysis and ecotoxicity test on 2 types of plants must be carried out, by obtaining germination and plant biomass greater than 90% of the reference characteristics. Evidence must be demonstrated via a modified test according to DIN EN 13432:2001. Material characterisation: minimum 50% organic matter (test for dry and volatile solids content) and material free of heavy metals. Quantification test for heavy metals and fluorine: Zn, Cu, Ni, Cd, Pb, Hg, Cr, Mo, Se, As and F.

[0021] Following table shows the differences between Industrial compost and home compost: Industrial compost Home compost Composting temperature55-60 °C20-30 °CMaterial biodegradation> 90% in max. 6 months> 90% in max. 12 monthsDisintegration of the final productWithin maximum 3 months > 90% of the material passes through a 2x2 mm meshWithin maximum 6 months > 90% of the material passes through a 2x2 mm meshEcotoxicityCompost without ecotoxicityCompost without ecotoxicityHeavy metalsWithout exceeding the legal limitsWithout exceeding the legal limits Summary of the invention

[0022] It is an object of the invention to propose a capsule for preparing an infusion beverage from the interaction between an infusion product and a liquid which is home compostable and easy to produce. The capsule must further avoid migration of the material into the infusion product. This purpose is achieved by a capsule of the type indicated at the beginning, characterized in that said capsule body is made of a capsule body material comprising PBS (polybutylene succinate), PBAT (polybutylene adipateterephthalate), polylactic acid (PLA), thermoplastic starch (TPS), polyhydroxyalkanoates (PHA), regenerated cellulose or combinations thereof and at least one catalysator for enhancing the biodegradability of said capsule body, said at least one catalysator comprising one among the group of polyphosphate salts, phthalates, epoxides or combinations thereof.

[0023] In the present invention, "polyhydroxyalkanoate (PHA)" refers to biodegradable, thermoplastic aliphatic polyesters which may be produced by polymerization of the respective monomer hydroxy aliphatic acids (including dimers of the hydroxy aliphatic acids), by bacterial fermentation of starch, sugars, lipids, or the like. PHA consists of one or more of: poly-beta-hydroxybutyrate (PHB) (also known as poly-3-hydroxybutyrate); poly-alpha-hydroxybutyrate (also known as poly-2-hydroxybutyrate); poly-3-hydroxypropionate; poly-3-hydroxyvalerate; poly-4-hydroxybutyrate; poly-4-hydroxyvalerate; poly-5-hydroxyvalerate; poly-3-hydroxyhexanoate; poly-4-hydroxyhexanoate; poly-6-hydroxyhexanoate; polyglycolic acid; etc., including copolymers, such as poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV); Polyhydroxybutyrate-hexanoate (PHBH); blends, mixtures, combinations, etc., of different PHA polymers.

[0024] In the invention an infusion beverage refers to any type of edible infusion prepared from a hot or cold liquid, and preferably water. Infusion products according to the invention comprise infusion products such as, for example, coffee, tea, mate infusion or other beverages such as liquid chocolate, soup or even juices obtained from any product soluble in liquids such as water or the like.

[0025] Infusion beverages according to the invention are prepared by introducing a liquid, preferably hot water, under a pressure of between 1 and 20 bar in the capsule containing infusion product.

[0026] Back to the invention, the provision of a catalysator comprising one among the group of polyphosphate salts, phthalates, epoxides or combinations thereof in the body capsule material having a base of PBS (polybutylene succinate), PBAT (polybutylene adipateterephthalate), polylactic acid (PLA), thermoplastic starch (TPS), polyhydroxyalkanoates (PHA), regenerated cellulose provides an accelerated compostability reaction after use of the capsule. This leads to a degree of compostability fulfilling not only the requirements of an industrially compostable capsule body which improves the prior art capsules, but also to a capsule fulfilling the requirements for home compost, that is all the four requirements previously cited.

[0027] It has also been found that due to the relatively high thickness required in the capsule body to withstand the harsh pressure and temperature conditions for the beverage preparation, the aforementioned materials cannot easily disintegrate beyond 90% in home composting conditions. Disintegration under composting conditions comprises first a degradation step, in which long chains of the polymer are broken into smaller pieces (oligomers and monomers), and then these smaller components are assimilated by microorganisms. This first step is extremely important, otherwise microorganisms are not able to digest the product. It is enhanced in non-crystalline regions of the polymer, around different atoms to those of the carbon-based backbone, i.e., nitrogen or oxygen atoms, and / or with hydrophilic components, which benefit enzymatic catalysed hydrolytic degradation.

[0028] In this context, it has been surprisingly observed that compostability is especially accelerated by adding the cited polyphosphate salts, phthalates, epoxides to the base material or blend with which the capsule body is produced. These components are often used in the food industry or in the production of plastics suitable for contact with food, as plasticisers, as they reduce the glass transition temperature, increasing the flexibility and elasticity of the plastics. The higher the proportion of plasticisers, the greater the flexibility achieved.

[0029] The invention further includes several preferred features that are object of the dependent claims and the utility of which will be highlighted hereinafter in the detailed description of an embodiment of the invention.

[0030] When the focus is put on home compostability speed optimization, then it is especially preferable to use polyphosphate salts among the preferred catalysator. In this case it is preferable that said polyphosphate salt is at least one among sodium polyphosphate, potassium polyphosphate or combinations thereof. It has been surprisingly found that polyphosphate salts have some advantages over other compounds when improving disintegration during the composting process. Polyphosphates are highly hydrophilic and therefore represent a good starting point for degradation of the polymeric chain. Once detached from the matrix, they provide an optimum fertilizer for the compost medium, thus surprisingly boosting the assimilation of the product by the microorganisms.

[0031] In the case of polyphosphates, they are indispensable compounds in the formulation of mineral fertilisers. Their absence limits plant growth. It is very common for phosphate-rich fertilisers to be used to induce and strengthen flowering. Phosphates are also widely used ingredients in the food industry, due to their multifunctionality, from emulsifiers, stabilisers, anti-caking agents, etc. However up to date, surprisingly no relation had been found as home compost enhancers.

[0032] It has also been found that a satisfactory composting speed in combination with a good workability, e.g., by injection moulding, extrusion or the like, is obtained when said capsule body material comprises between 60% to 98% w / w of biodegradable PBS, PBAT, PLA, TPS, PHA, regenerated cellulose or combinations thereof and between 0.5 and 5% w / w of said at least one catalysator, and more preferably between 0.5 and 2% w / w.

[0033] Another problem that the invention seeks to solve is how to improve the barrier properties to oxygen and water vapour of the capsule, as well as the mechanical properties in terms of pressure withstand and resistance to temperature of extraction in the infusion beverage machine without degrading.

[0034] In the invention, a material having barrier properties, being it either the capsule body or the lid, refers to a material which does neither let oxygen nor vapour pass therethrough or allows it to pass at very low levels. Particularly preferably, the barrier materials according to the invention are those having an oxygen transmission rate (OTR) of less than or equal to 0.1 cm 3< / (package 1 bar per day) and a water vapour transmission rate (WVTR) of less than 0.01 g / (package·1bar·day). These rates are measured at an environment temperature of 23°C and 50% of relative humidity. In the measurement the package of the oxygen and vapour transmission rates refers to the capsule body or the lid individually, that is, not when the capsule is closed, since the results could be strongly biased due to the combination of different materials and the risk that oxygen or vapour exits through the interface of both parts.

[0035] Among the possible biodegradable materials for the capsule body material, it is especially preferred to use PHA and that said polyhydroxyalkanoate of said capsule body material consists of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV), Polyhydroxybutyrate-hexanoate (PHBH), or combinations thereof. These PHA materials in combination with the cited catalysators are preferred due to their optimum performance to be in contact with edible products, thus avoiding any kind of organoleptic infusion beverage affection.

[0036] In the invention said capsule body material further comprises one or several organic fillers, the total amount of said one or several organic fillers being between 5 and 25% w / w, and one or several inorganic fillers, the total amount of said one or several inorganic fillers being between 5 and 20% w / w. In this case, said capsule body material comprises between 60% to 89.5% w / w of biodegradable PBS, PBAT, PLA, TPS, PHA, regenerated cellulose or combinations thereof and between 0.5 and 5% w / w, preferably between 0.5 and 2% w / w, of said at least one catalysator.

[0037] In a further preferred embodiment, said capsule body material comprises between 70% to 89.5% w / w of biodegradable PBS, PBAT, PLA, TPS, PHA, regenerated cellulose or combinations thereof. Being able to maintain a large amount of biodegradable PBS, PBAT, PLA, TPS, PHA, regenerated cellulose or combinations thereof in the composition is further advantageous to maintain the high thickness required in the capsule body to withstand the harsh pressure and temperature conditions for the beverage preparation.

[0038] More preferably, said capsule body material comprises between 75% to 85% w / w of biodegradable PBS, PBAT, PLA, TPS, PHA, regenerated cellulose or combinations thereof.

[0039] Even more preferably, said capsule body material comprises between 75% to 81.5% w / w of biodegradable PBS, PBAT, PLA, TPS, PHA, regenerated cellulose or combinations thereof.

[0040] Within these narrower ranges of biodegradable PBS, PBAT, PLA, TPS, PHA, regenerated cellulose or combinations thereof in the composition of the body capsule material, the optimal synergistic effects with the fillers are obtained. This allows to maintain the high thickness required in the capsule body to withstand the harsh pressure and temperature conditions for the beverage preparation, while ensuring an optimal mechanical stability and an optimal pierceability without compromising the biodegradability and compostability of the capsule.

[0041] It has been found that the characteristics of a conventional capsule body, biodegradable PBS, PBAT, PLA, TPS, PHA, regenerated cellulose or combinations sometimes can be improved in terms of mechanical properties.

[0042] The combination of components, that is biodegradable PBS, PBAT, PLA, TPS, PHA, regenerated cellulose or combinations, with the catalysator, together with one or several organic fillers and one or several inorganic fillers, provides for a capsule which is at least industrially compostable, but at the same time offers improved barrier properties, as well as an even better resistance to pressure and temperature, thus reducing problems of deformation and breakage in use.

[0043] Organic fillers help to further improve the degradation of the capsule material and thus compostability. It has further been found that a percentage of organic fillers beyond 25% w / w in the material composition leads to an increase in the porosity of the capsule body, thus harming the oxygen and vapour barrier of the capsule. Below 5% w / w of organic filler no improvements on the degradation are clearly detectable.

[0044] Similarly, as in the case of the organic filler, a percentage of inorganic filler below 5% w / w provides no improvement in the desired properties. On the other hand, a percentage beyond 20% w / w of inorganic filler causes excessive crystallisation, thus leading to an increased brittleness of the capsule body walls.

[0045] The synergy obtained by the indicated capsule body material composition improves the degradation and disintegration times of the capsule, thus noticeably improving the industrial compostability without harming other important mechanical properties. The effects of disintegration begin to be very apparent as from week 11 after the preparation of the infusion beverage, but the disintegration must take place within a period of maximum 26 weeks.

[0046] In a preferred embodiment seeking for optimum compatibility with edible products as the infusion products contained in the capsule said one or several organic fillers of said capsule body material consists of at least one among small amorphous cellulose, crystalline cellulose, wood fibers, soja oil, starch, polycaprolactone (PCL), or combinations thereof.

[0047] In an especially preferred embodiment, the total amount of said one or several organic fillers is between 10 and 20% w / w of said capsule body material, providing an even more optimal compromise between oxygen and vapour barrier and mechanical and thermal properties.

[0048] In another embodiment also seeking to choose the most synergetic materials with the organic fillers with the purpose of improving the barrier properties and giving more strength to the capsule, said one or several inorganic fillers of said capsule body material consists of at least one among talc, mica, calcium carbonate, alumina, clay, glass fibre, kaolinite or combinations thereof.

[0049] Especially preferably the total amount of said one or several inorganic fillers is between 8 and 15% w / w of said capsule body material, which has been found to be an optimum proportion for an easy pierceability of the capsule, without notably harming the stiffness thereof.

[0050] In a further preferred embodiment, also seeking to choose the most synergetic composition with the purpose of achieving an optimal balance between mechanical and thermal performance and biodegradability and compostability of the capsule, said capsule body is made of a capsule body material comprising [i] between 75% to 81.5% of biodegradable PBS, PBAT, PLA, TPS, PHA, regenerated cellulose or combinations thereof, and [ii] between 0.5% and 2% w / w of at least one catalysator for enhancing the biodegradability of said capsule body, said at least one catalysator comprising one among the group of polyphosphate salts, phthalates, epoxides or combinations thereof, and [iii] one or several organic fillers, the total amount of said one or several organic fillers being between 10 and 20% w / w, and [iv] one or several inorganic fillers, the total amount of said one or several inorganic fillers being between 8 and 15%.

[0051] Preferably the lid material of said capsule is different to the capsule material to have a better adaptation to the operation requirements of each part.

[0052] It is also desirable to achieve a completely industrially or home compostable capsule, which simultaneously also offers enough barrier to oxygen and water vapour. Oxygen has a direct impact on organoleptic properties of the infusion product. At its time, in infusion products such as coffee, the increase in humidity causes the coffee to acidify, the pH of what is extracted in the coffee capsule drops considerably and the change in organoleptic properties is noticed in the cup. This leads to unpleasant metallic acid taste that the coffee did not originally have. As humidity increases, the acidification process increases. To avoid this undesired effect, further to the properties already mentioned for the capsule body, in a preferred embodiment seeking for total industrial or home compostability said lid is made of a sheet of lid material comprising one among cellulose covered at least with a watertight coating layer, PLA (polylactic acid), PCL (plycaprolactone), PBS (polybutylene succinate), PBAT (Polybutylene adipate terephthalate), or combinations thereof.

[0053] In a preferred embodiment said watertight coating layer of said lid material is one among the group of aromatic or aliphatic polyisocyanates, anionic copolymer emulsions (such as polyvinylidene chloride emulsion), polyurethane dispersions, or combinations thereof.

[0054] Preferably, said capsule comprises a sealing member which is separated from the capsule body. The separated sealing member can have different mechanical properties than the rest of the capsule and thus deform more easily than the rest of the capsule. This create an improved watertight seal between a leading sealing edge of an enclosing member configured to receive the capsule when used in a device for preparing infusion beverages.

[0055] Preferably, the sealing member is made of a compostable material. Different materials can be applied in this case such as a cardboard, cellulose, paper, or biopolymers such as PLA (polylactic acid), PCL (polycaprolactone), PBS (polybutylene succinate), PBAT (polybutylene adipate terephthalate), TPS (thermoplastic starch), PHA (polyhydroxyalkanoate) or the like. Thanks to the material choose, the capsule body and the sealing member can be composted without any intermediate handling or separation.

[0056] More preferably, in order to simplify the production thereof the sealing member is a planar, circular annular ring of a compostable material. Other shapes different to circular are also conceivable, such as a polyhedron. Although the ring is in this case planar, it could also have other cross sections such as semi-circular, triangular, saw-shaped like or the like.

[0057] Finally, the sealing member can be attached to the flange of the capsule body with an adhesive layer or with holding elements formed in the capsule body.

[0058] To simplify the production process of the capsule, said capsule body is further injection moulded or compression moulded from said body material.

[0059] Finally, it has been found that a good compromise between compostability time and conservation of mechanical and thermal properties of the capsule body is obtained when said capsule body wall thickness is comprised between 0.3 and 0.8 mm.

[0060] In an embodiment seeking for improved processability by injection moulding, the flowability index of said capsule body material is comprised between 20-40g / 10min.

[0061] Preferably to improve the thermal resistance of the capsule body, the heat deflection temperature (HDT) of said capsule body material is comprised between 130 and 160°C.

[0062] Likewise, the invention also includes other features of detail illustrated in the detailed description of an embodiment of the invention and in the accompanying figures.Brief description of the drawings

[0063] Further advantages and features of the invention will become apparent from the following description, in which, without any limiting character, preferred embodiments of the invention are disclosed, with reference to the accompanying drawings in which: Figure 1 shows a first embodiment of the capsule according to the invention. Figure 2 shows a detailed view of the flange like rim of the capsule of Figure 1. Figure 3 shows the capsule of Figure 1 before closing the infusion device. Figure 4 shows the capsule of Figure 1 once the infusion device is in operation position. Figure 5 shows a second embodiment of the capsule according to the invention. Figure 6 shows a detailed section view of the capsule of Figure 5. Figure 7 shows a detailed section view of the third embodiment of the capsule of according to the invention. Figure 8 shows a perspective view of a fourth embodiment of the capsule according to the invention. Figure 9 shows a detailed perspective view of the sealing member of the capsule of Figure 8. Figure 10 shows a detailed longitudinal view of the capsule of Figure 8. Detailed description of embodiments of the invention

[0064] Figures 1 to 4 show a first embodiment of a capsule 1 for preparing an infusion beverage from the interaction between an infusion product 22 and a liquid, it being preferably cold or hot water. In the case of hot water, the fluid can also comprise vapour.

[0065] The capsule 1 comprises a capsule body 2 and a lid 4.

[0066] The capsule body 2 is cup-shaped defining a main axis 8. More particularly, the capsule body 2 is frustoconical, having a small base 10 at the upper part of the capsule body 2, and a large base 12 at the lower part of the capsule body 2 thus forming a frustoconical body. However, the capsule body 2 according to the invention could also have other shapes, such as cylindrical, lenticular or the like.

[0067] The capsule 1 further comprises a perimetrical flange 18, shaped as an annular ring protruding radially outwardly from the large base 12 of the capsule body 2. Preferably the annular ring is circular.

[0068] The capsule body 2 and the lid 4 are mutually connected to one another at the flange 18 for creating a closed infusion chamber 6, containing the infusion product 22, as shown in Figure 2.

[0069] The capsule 1 has further an injection side 14 corresponding to the small base 10 and an extraction side 16. The side of the annular flange 18 facing the injection side 14, that is the side of the flange opposite to the lid 4, the capsule 1 further comprises a sealing member 20. This sealing member 20 is responsible of providing a sealing engagement with a device 100 for preparing infusion beverages, as it will be explained below.

[0070] In this embodiment, the sealing member 20 comprises an annular groove 24 concentrically surrounding the capsule body 2. The annular groove 24 is formed by two walls, that is a side wall 26 of the capsule body 2 and a remote wall 28, remotely located from the capsule body 2. As it is apparent from Figure 2, the annular groove 24 narrows from the injection side 14 towards the extraction side 16 in a triangular cross section. Other narrowing shapes could also be possible, for example if the groove 24 had a semi-circular shape. Preferably said annular groove is V shaped, U shaped or has a flat bottom between the side and remote walls 26, 28.

[0071] The groove has further a bottom 30 which in this case is formed by the vertex of intersection between the side wall 26 and the remote wall 28. The vertex is rounded with a rounding radius. Alternatively, the bottom 30 could also have a protrusion at the bottom configured to provide another sealing point.

[0072] The sealing member 20 is in this case integrally formed with the capsule body 2. However, it could also be a separate ring of a different biodegradable material. In other words, although it is more cost efficient, it is not essential for the invention that the sealing member 20 is physically part of the capsule body 2 as one single structure.

[0073] The side wall 26 in the region of the annular groove 24 slopes between 5 and 20° relative to the main axis 8. The remote wall 28 slopes between 15 and 45° relative to the main axis 8. Furthermore, the annular groove has a maximum height comprised between 0.8 and 3 mm measured from the lowest point of said extraction side 30 and a depth comprised between 0.5 and 1.5 mm measured from said maximum height, to the bottom 30 of the annular groove 24.

[0074] Seeking for a faster composting speed which achieves the requirements for the capsule being considered a home compost product, the capsule body material further comprises at least one catalysator for enhancing the biodegradability thereof.

[0075] In this embodiment, the capsule body 2 is made of a capsule body material comprising 98% w / w of a biodegradable PHBH and 2% w / w of sodium polyphosphate. Thanks to this blend a capsule is obtained fulfilling the requirements of a home compostable capsule.

[0076] In an alternative embodiment, the capsule of Figures 1 to 4, the capsule body 2 is made of a capsule body material comprising 79% w / w of a PHBH, 10% of an organic filler which is cellulose and 10% of an inorganic filler, which in this embodiment is talc, and 1% w / w of sodium polyphosphate.

[0077] Preferably, the capsule body 2 is injection moulded from capsule body material indicated in the previous paragraph. Alternatively, the capsule body 2 could also be compression moulded. Also, to achieve good mechanical and thermal properties, as well as a good industrial or home compostability, the capsule body 2 has wall thickness 34 which comprised between 0.3 mm and 0.8 mm.

[0078] The flowability index of the capsule body material is comprised between 20-40g / 10min, and the heat deflection temperature (HDT) thereof is comprised between 130 and 160°C.

[0079] On the other hand, to avoid having to separate the lid 4 from the capsule body 2 prior to composting, the lid 4 is made of a sheet of cellulose. This provides for a 100% home compostable capsule 1, without preprocessing requirements such as materials separation prior to composting. Furthermore, to obtain good vapour and oxygen barriers properties, the sheet covered with a watertight coating layer 32 of an aliphatic polyisocyanate. The coating layer 32, diagrammatically indicated with a dashed line in Figure 1.

[0080] The synergy obtained by all these components improves the degradation and disintegration times of the capsule 1. However, simultaneously that capsule, although being industrially compostable, reaches good oxygen and vapour barrier properties and is rigid and thermally stable enough.

[0081] Figures 3 and 4 show the device 100 for preparing infusions beverages comprising an enclosing member 102 configured to receive the capsule 1 and having a leading sealing edge 104, and an extraction wall 106. The device 100 is configured to prepare an infusion beverage by causing the liquid to pass under pressure through the infusion chamber 6.

[0082] The device 100 for preparing infusion beverages, has a resting position in which the leading sealing edge 104 of the enclosing member 102 is located remotely from the extraction wall 106 and an operative position in which the leading sealing edge 104 is close to the extraction wall, such that when the capsule 1 in inserted in the device, the sealing member 20 can be compressed between the sealing leading edge 104 and the extraction wall 106 to provide fluid tightness during the preparation of the infusion beverage, as detailed below. In this example, the enclosing member 102 is movable towards the extraction wall 106. However, other configurations are also possible, such as the extraction wall 106 being movable towards a static enclosing member 102 or that both parts are movable relative to each other.

[0083] Hereinafter and referring to Figures 3 and 4, a detailed explanation will be given of the operation of the first embodiment of the capsule 1 of the invention. The device 100 for preparing infusion beverages has a liquid injection pump 114 for supplying liquid to the enclosing member 102, i.e., liquid injection cylinder. For the preparation of the infusion beverage, the capsule 1 is inserted inside the enclosing member 102. Figures 3 and 4 show the instant prior to moving to the operative position. Particularly, in Figure 3, the enclosing member 102 has approached the flange 18 of the capsule 1 and has started to pierce the small base 10 of the capsule 1 with the punches 108. On the extraction side 16, the device 100 has the extraction wall 106 provided with a plurality of piercing members 110 for piercing the lid 4 of the capsule 1, when the device 100 is in the operative position of the enclosing member 102. Furthermore, this extraction wall 106 106 has a plurality of outlet passages 112 for the prepared infusion to flow out thereof during the operation of the device 1.

[0084] When the enclosing member 102 moves from the position shown in Figure 3 to the operative position of the enclosing member 102, shown in Figure 4, the enclosing member 102 moves the capsule 1 via the sealing leading sealing edge 104 in the direction of the extraction wall 106. When the lid 4 abuts the extraction wall 106, the enclosing member 112 has not yet reached the end of its stroke. From this first contact between the leading sealing edge 104 and sealing member 20, the leading sealing edge 104 is inserted in the groove 24 and sealingly compresses simultaneously the side wall 26 of the capsule body 6 and the remote wall 28. The enclosing member 112 starts thus deforming the sealing member 20 at the side wall 26 of the capsule body 2 and the remote wall 28. Finally, when the enclosing member 112 reaches the end of its stroke.

[0085] At this point, the fluid is injected into the infusion chamber 6 with the injection pump 114 at a pressure comprised between 1 and 20 bar. Since the sealing member 20 is compressed and deformed between the enclosing member 102 and the extraction wall 106, a watertight sealing engagement is obtained between the device 1 and the capsule 1. Owing to the tight sealing engagement, the water can flow only through the perforations in the small base 10 of the capsule body 2, and flow inside the infusion chamber 6.

[0086] Once the liquid impregnated with the infusion product contained in the infusion chamber 6 exits the infusion chamber 6 through the lid 4, it reaches the outlet passages 112 and now flows towards the outside as an infusion beverage by way of a manifold of the device 1 not shown in the drawings.

[0087] In another embodiment, the sealing member 20 can be a triangular protrusion concentrically arranged around the capsule body 2, like the one of Figures 1 and 2. This concentrical protrusion can be, e.g., of triangular, semi-circular, or similar cross-sections, and be radially distanced from the main axis 8 such as the tip thereof to be compressed by the sealing leading edge 104 of the enclosure member 102 of the device 100 for preparing the infusion beverages.

[0088] The following embodiments of the capsule 1 of the invention share many features with the embodiment described in Figures 1 to 4. Therefore, for these common features reference is made to the previous paragraphs, while below the new features will be explained in detail.

[0089] The capsule 1 for preparing an infusion beverage from the interaction between an infusion product and a liquid of Figures 5 and 6 comprises also a capsule body 2 and a lid 4 which are mutually connected to one another for creating a closed infusion chamber 6 containing said infusion product 22.

[0090] The capsule body 2 is made of a capsule body material comprising a biodegradable PLA in an amount between 60% to 98% w / w, 0.5 to 5% w / w of a catalysator, one or several organic fillers, the total amount of said one or several organic fillers being between 5 and 25% w / w, and one or several inorganic fillers, the total amount of said one or several inorganic fillers being between 5 and 20% w / w.

[0091] In particular, the capsule body material for injection moulding of the capsule body 2 in this case comprises 70% w / w of PLA, 15% w / w of cellulose, 13% w / w of talc and 2% w / w of sodium polyphosphate.

[0092] Additional components could be added to the capsule body material components, such as colorants or others.

[0093] Regarding the lid 4, in this case is made of a sheet of lid material comprising a mixture of PLA and PCL.

[0094] Finally, in this case the capsule 1 of this second embodiment has sealing member 20 which is separated from the capsule body 2. In particular, the sealing member 20 is a planar, circular annular ring of a compostable material. Other shapes different to circular are also conceivable, such as a polyhedron. Different materials can be applied in this case such as a cardboard, cellulose, paper or biopolymers such as PLA (polylactic acid), PCL (plycaprolactone), PBS (polybutylene succinate), PBAT (polybutylene adipate terephthalate), TPS (thermoplastic starch), PHA (polyhydroxyalcanoate) or the like. Although the ring is in this case planar, it could also have other cross sections such as semi-circular, triangular, saw-shaped like or the like. Finally, the sealing member 20 can be attached to the flange 18 with an adhesive layer or with holding elements formed in the capsule body 2.

[0095] Regarding the way to use the capsule 1 of this embodiment, reference is made to previous paragraphs.

[0096] Figure 7 shows a third embodiment of the capsule of the invention. In this case, the capsule body 2 is made of a capsule body material of 75% w / w of PBS, 15% w / w of starch, 8% w / w of calcium carbonate and 1.8% of epoxyde and 0.2 % w / w of colouring agent.

[0097] In this case, the lid 4 is made from a cellulose sheet with a coating layer 32 of aliphatic polyisocyanate. Differently to the previous embodiments, in this case, the coating layer 32 is arranged on the side of the lid 4 facing the infusion chamber 6.

[0098] Finally, in this case, the sealing member 20 of the capsule 1 is injection formed together with the capsule body 2 as a plurality of concentrical ridges with triangular cross-section.

[0099] Figures 8 to 10 show a fourth embodiment of the capsule 1 of the invention. The main difference in this case is the sealing member 20.

[0100] The sealing member 20 comprises a plurality of isolated blind openings 36 or holes penetrating in the upper surface of the sealing member 20. The blind openings 36 are arranged distanced to the main axis 8 defining the capsule center. The sealing member 20 is made from the same material as the capsule body 2 and is integral with the capsule body 2.

[0101] These blind openings 36 are evenly distributed along the sealing member 20 for providing a homogeneous sealing behaviour. This blind opening pattern provides compensation when the capsule is not 100% centered relative to the enclosing member 102.

[0102] The blind openings 36 can have any shape, such as cylinder, prism, tethraedron or the like.

[0103] In this embodiment, the capsule body 2 is made of a capsule body material of 80% w / w of PHBH, 10% w / w of cellulose, 8% w / w of calcium carbonate and 1% of sodium polyphosphate and 1% of potassium polyphosphate. The lid 4 is made of a sheet of PBS.

[0104] Thanks to the composition of the capsule body material, and when required the lid material, the capsules according to the invention are compostable and easy to produce. However, they have a good barrier to oxygen and water vapour and withstand the pressure and temperature of extraction in the infusion beverage device without degrading.

Claims

1. A capsule (1) for preparing an infusion beverage from the interaction between an infusion product (22) and a liquid, said capsule (1) comprising [a] a capsule body (2) and [b] a lid (4), [c] said capsule body (2) and said lid (4) being mutually connected to one another for creating a closed infusion chamber (6) containing said infusion product (22), characterized in that [d] said capsule body (2) is made of a capsule body material comprising [i] between 60% to 89.5% w / w of biodegradable PBS, PBAT, PLA, TPS, PHA, regenerated cellulose or combinations thereof, and [ii] between 0.5 and 5% w / w, preferably between 0.5 and 2% w / w of at least one catalysator for enhancing the biodegradability of said capsule body (2), said at least one catalysator comprising one among the group of polyphosphate salts, phthalates, epoxides or combinations thereof, and [iii] one or several organic fillers, the total amount of said one or several organic fillers being between 5 and 25% w / w, and [iv] one or several inorganic fillers, the total amount of said one or several inorganic fillers being between 5 and 20% w / w.

2. The capsule (1) according to claim 1, characterized in that said polyphosphate salt is at least one among sodium polyphosphate, potassium polyphosphate or combinations thereof.

3. The capsule (1) according to claims 1 or 2, characterized in that said capsule body material comprises between 70% to 89.5% of biodegradable PBS, PBAT, PLA, TPS, PHA, regenerated cellulose or combinations thereof.

4. The capsule (1) according to claims 1 to 3, characterized in that said capsule body material comprises between 75% to 85% w / w of biodegradable PBS, PBAT, PLA, TPS, PHA, regenerated cellulose or combinations thereof.

5. The capsule (1) according to any of claims 1 to 4, characterized in that said polyhydroxyalkanoate of said capsule body material consists of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV), Polyhydroxybutyrate-hexanoate (PHBH), or combinations thereof.

6. The capsule (1) according to claims 1 to 5, characterized in that said one or several organic fillers of said capsule body material consists of at least one among small amorphous cellulose, crystalline cellulose, wood fibers, soja oil, starch, polycaprolactone (PCL), or combinations thereof.

7. The capsule (1) according to claims 1 to 6, characterized in that the total amount of said one or several organic fillers is between 10 and 20% w / w of said capsule body material.

8. The capsule (1) according to any of claims 1 to 7, characterized in that said one or several inorganic fillers of said capsule body material consists of at least one among talc, mica, calcium carbonate, alumina, clay, glass fibre, kaolinite or combinations thereof.

9. The capsule (1) according to claim 1 to 8, characterized in that the total amount of said one or several inorganic fillers is between 8 and 15% w / w of said capsule body material.

10. The capsule (1) according to any of claims 1 to 9, characterized in that said lid (4) is made of a sheet of lid material comprising one among cellulose covered at least with a watertight coating layer (32), PLA, PCL, PBS, PBAT or combinations thereof.

11. The capsule (1) according to any of claim 10, characterized in that said watertight coating layer (32) of said lid material is one among the group of aromatic or aliphatic polyisocyanates, anionic copolymer emulsions, polyurethane dispersions, or combinations thereof.

12. The capsule (1) according to any of claims 1 to 11, characterized in that it comprises a sealing member (20) which is separated from the capsule body (2).

13. The capsule (1) according to any of claims 1 to 11, characterized in that said capsule body (2) is injection moulded or compression moulded from said capsule body material.

14. The capsule (1) according to any of claims 1 to 12, characterized in that said capsule body (2) wall thickness (34) is comprised between 0.3 and 0.8 mm.

15. The capsule (1) according to any of claims 1 to 13, characterized in that the flowability index of said capsule body material is comprised between 20-40g / 10min.

16. The capsule (1) according to any of claims 1 to 14, characterized in that the heat deflection temperature (HDT) of said capsule body material is comprised between 130 and 160°C.

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