BIODEGRADABLE TOP MEMBRANE FOR A BEVERAGE CAPSULE

Abstract

The present invention relates generally to the field of beverage capsules. In particular, the present invention relates to a biodegradable top membrane of a beverage capsules. The biodegradable top membrane of a beverage capsule is pierceable by injection means of a beverage preparation machine which are adapted to inject an extraction liquid under pressure inside a closed chamber containing a mass of soluble and/or extractable food material. Remarkably, the top membrane possesses the necessary physical properties to be useful for beverage capsules while being biodegradable. The biodegradable top membrane for a beverage capsule comprises at least one polyhydroxyalkanoate (PHA).

Claims

1. A capsule for use in a beverage preparation machine, said capsule containing a soluble and/or extractable beverage ingredient and said capsule comprising: a capsule body comprising: a side wall defining a chamber and extending axially between a top opening and a bottom outlet, a circumferential annular flange projecting radially outward from the top opening, said flange comprising an upper surface opposite to the chamber with respect to the opening and an opposed lower surface, and a top membrane attached to at least a part of the upper surface of the circumferential flange, said top membrane closing the top opening, and presenting a portion adapted to be punctured for liquid injection into the capsule, a bottom membrane provided inside the chamber so as to delimit an ingredient chamber between the top membrane and said bottom membrane, said ingredient chamber containing a beverage ingredient, an opening device provided inside the chamber for opening the capsule by relative engagement of said opening device with the bottom membrane under the effect of a rise in pressure of the injected liquid in the ingredient chamber, and wherein the top membrane is biodegradable and comprises at least one film of a at least one polyhydroxyalkanoate (PHA).

2. A capsule according to claim 1, wherein the at least one PHA is selected from the group consisting of P (3HB-co-3HV), PHB copolymers, P (3HB-co-3HHx), P (3HB-co-4HB), P (3HB), P (3HB-co-3HV), P (3HB-co-3HO), P (3HB-co-3Hod) and combinations thereof.

3. A capsule according to claim 1, wherein the at least one film of a at least one polyhydroxyalkanoate (PHA) is a sealant layer of the top membrane, and said film comprises at least 30% in weight PHA.

4. A capsule according to claim 1, wherein the top membrane has a material thickness in the range of about 120 to 150 μm.

5. A capsule according to claim 1, wherein at least the portion of the top membrane adapted to be punctured for liquid injection presents: a tensile strength higher than 1 MPa, and an elongation at break superior to 100%.

6. A capsule according to claim 1, wherein said top membrane is a multilayer film and said multilayer film comprises at least: a first layer film of PHA blended with one or more biopolymers, and a second layer film of at least one polybutylene succinate.

7. A capsule according to claim 6, wherein said multilayer film comprises a bottom layer film, said bottom layer being configured to be sealed to at least a part of the upper surface of the circumferential flange of the capsule body, and wherein bottom layer film is different from the second layer film of at least one polybutylene succinate (PBS).

8. A capsule according to claim 6, wherein the top membrane is manufactured by a process comprising a step of co-extruding the two layer films, and comprising a step of laminating a print layer and/or a step of laminating a water vapor transmission barrier layer.

9. A capsule according to claim 1, wherein the capsule body is made of biodegradable materials.

10. System of a capsule for use in a beverage preparation machine, said capsule containing a soluble and/or extractable beverage ingredient and said capsule comprising: a capsule body comprising: a side wall defining a chamber and extending axially between a top opening and a bottom outlet, a circumferential annular flange projecting radially outward from the top opening, said flange comprising an upper surface opposite to the chamber with respect to the opening and an opposed lower surface, and a top membrane attached to at least a part of the upper surface of the circumferential flange, said top membrane closing the top opening, and presenting a portion adapted to be punctured for liquid injection into the capsule, a bottom membrane provided inside the chamber so as to delimit an ingredient chamber between the top membrane and said bottom membrane, said ingredient chamber containing a beverage ingredient, an opening device provided inside the chamber for opening the capsule by relative engagement of said opening device with the bottom membrane under the effect of a rise in pressure of the injected liquid in the ingredient chamber, and wherein the top membrane is biodegradable and comprises at least one film of a at least one polyhydroxyalkanoate (PHA) and a beverage preparation machine, said machine comprising a liquid injection hollow needle to inject an extraction liquid under pressure inside or into the chamber

11. System according to claim 9, wherein the beverage preparation machine comprises: a capsule holder for receiving and holding the capsule in the beverage preparation machine, a capsule holder receiving area for inserting the removable capsule holder, and wherein the liquid injection hollow needle and the inserted capsule holder are relatively moveable one to the other so that the liquid injection hollow needle punctures the top membrane of the capsule.

12. (canceled)

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0105] Further features, advantages and objects of the invention will become apparent for the skilled person when reading the following detailed description of embodiments of the invention and when taking in conjunction with the figures of the enclosed drawings. In case numerals have been omitted from a figure, for example for reasons of clarity, the corresponding features may still be present in the figure.

[0106] FIG. 1 shows a schematic cross-section of a capsule according to the present invention,

[0107] FIG. 2 shows a system of a capsule and beverage preparation machine according to the invention,

[0108] FIGS. 3A and 3B are cross section views of the capsule and the capsule holders of FIGS. 1 and 2 in two different operations,

[0109] FIG. 4 shows examples of structures of the biodegradable top membrane in accordance with the present invention.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS

[0110] FIG. 1 illustrates schematically a capsule 1 used in the system of the present invention.

[0111] The capsule 1 comprises a capsule body 2 with one or more sidewall(s) 22 that extend axially from a bottom towards a top. The sidewall extends towards a top opening 23. At the top opening 23, the body comprises a circumferential flange 24 that extends radially outward from the sidewall and that continuously extend along the circumference of the opening. Usually, the flange 24 is connected with the capsule body by a connecting portion 243. For example, at the connecting portion 243 the sidewall(s) 22 may transition into the flange 24. The flange 24 is usually integrally formed with the one or more side walls 22. The flange comprises an upper surface 241 facing the top and a lower surface 242. The lower surface preferably comprises, or consists of, a flat surface.

[0112] Generally, any transversal cross section of the body capsule is circular from the bottom to the top and the flange is circular too as illustrated in the perspective view of FIG. 2.

[0113] The sidewall delimits a chamber 21 for containing a soluble and/or extractable beverage ingredient.

[0114] This soluble beverage ingredient is a water soluble powder ingredient and can be selected within the list of: instant coffee powder, milk powder, cream powder, instant tea powder, cocoa powder, soup powder, fruit powder or mixture of said powders. The powders can be agglomerated or sintered.

[0115] This beverage ingredient packed in the package can also be an ingredient able to be extracted or infused like a roast and ground coffee, or tea leaves. In that embodiment water extracts the beverage ingredient.

[0116] The capsule comprises a top membrane 3 that is fixed, sealed or attached to at least a part of the upper surface 241 of the circumferential flange and accordingly covers and closes the top opening 23.

[0117] This top membrane is adapted to be punctured for liquid injection into the capsule as illustrated in FIG. 3B. Preferably, the top membrane is pierceable by an injection needle of the beverage preparation machine which is adapted to inject an extraction liquid under pressure inside or into the chamber. Preferably, the puncturing operation is made at one single place by a water injection needle such as described in WO2006/082064 or WO2008/107281.

[0118] The term “top membrane” should be understood as the membrane which is pierced by the injection needle of machine, as opposed to the “bottom membrane” (such as described below) which should be understood as the membrane located on the opposite side of the capsule 1.

[0119] The capsule comprises a bottom membrane 4 that closes the bottom of the chamber 21. Accordingly, the soluble and/or extractable beverage ingredient is enclosed between the top and bottom membranes. The top and bottom membranes delimit an internal space of the chamber, the ingredient chamber 22, configured to hold the beverage ingredient for the preparation of a beverage.

[0120] In one embodiment, a distributor wall 6 can extend through the internal cross section of the chamber defining an inferior sub-chamber for the ingredient and a superior distribution chamber for the liquid. This distributor wall comprises small holes to distribute liquid uniformly on the ingredient.

[0121] The capsule comprises an opening device 5 adapted to open the chamber by relative engagement with the bottom membrane 4 under the effect of the liquid pressure increase in the chamber during injection of said liquid. The opening device 5 may comprise a rigid plate 51 comprising opening elements 52 such as spikes, cone- or pyramid-shaped—optionally truncated at their ends—on its surface turned upwardly towards the bottom membrane 4 which may form protrusions and recesses against the bottom membrane 4 facing the opening device. The opening device 5 may be generally referred to as “pyramid plate”. Upon liquid injection inside the chamber 4, pressure builds up, which deforms the bottom membrane 4 against the opening means 5, until the bottom membrane is pierced, giving way to the beverage prepared inside the capsule 1 respectively chamber 21 below the opening device 5. The expression “engagement” may mean that, for instance, the opening device or the second membrane, or alternatively both may be moved with respect to each other to effect opening.

[0122] Usually, the capsule body comprises a bottom beverage outlet 25, below the opening device 5. The bottom of the capsule body preferably extends below the opening means to hold said opening means and collect the beverage to this beverage outlet 25 dispensing the beverage outside of the capsule 1, e.g. into a cup.

[0123] The top membrane 3 is fixed to the flange 24 in such a way that the extraction liquid injected into the chamber 21 increases internal pressure up to the pressure necessary to obtain the piercing of the deformed bottom membrane 4 by the opening device 5. The top membrane 3 is thus fixed to the flange in such a way that it does not detach at least until a defined pressure inside of the chamber is achieved. This defined pressure may be at least 2 bars, preferably at least 3 bars or at least 6 bars. Thereby, the fixation effects that the capsule 1 does not leak via the interface between the flange and the top membrane during beverage preparation.

[0124] Preferably, at least the capsule body 2 and the top membrane 3 are made of compostable materials, even more preferably all the elements of the capsules are made of material(s) and/or contain substances that are (all) compostable.

[0125] Usually, the top membrane 3 is attached to the flange 24 by heat sealing, with or without the addition of sealant. Thus, a seal is formed between the top membrane and the flange.

[0126] FIG. 2 shows a system of a capsule 1 such as describes above and a beverage preparation machine 10 configured to prepare a beverage from said capsule. The machine comprises a capsule holder 11 removeable from the machine and comprising a receiving area 111 to introduce the body of the capsule while the flange 24 of the body is supported on the circumferential rim 112 of the holder. Then the capsule holder can be inserted in a receiving area 13 of the machine to prepare a beverage.

[0127] The machine comprises a capsule holder receiving area 13 for inserting the removable capsule holder where the capsule holder can be inserted to prepare a beverage.

[0128] In addition, the machine comprises, above the receiving area 13 for the capsule holder, a liquid injection device 12 with an injection member 121, precisely a hollow needle configured to pierce the top membrane 3 and to inject water inside the capsule. This injection device and the capsule holder are moveable relatively so as to clamp the circumferential annular flange of the capsule.

[0129] Then, the capsule holder 11 can be positioned in two positions inside the receiving area 13 as illustrated in FIGS. 3A and 3B.

[0130] In FIG. 3A, the capsule holder 11 has just been introduced inside the receiving area 13 and in FIG. 3B, the liquid injection plate 12 is moved to the inserted capsule holder and clamps the circumferential annular flange 24 of the capsule between the circumferential rim 112 of the holder and the injection plate 12.

[0131] FIG. 4 illustrates structures of the biodegradable top membrane 3 that can be used in the capsule of FIG. 1 and within the system of FIGS. 2A, 2B and 3.

[0132] All these top membranes are multilayer films comprising at least: [0133] a first layer film 31 of PHA blended with one or more biopolymers, and [0134] a second layer film 32 of at least one polybutylene succinate (PBS). [0135] a third layer film 33 enabling printing or creating water vapor transmission barrier is provided.

[0136] The first layer 31 is attached to the flange of the capsule body and preferably comprises a sealant.

[0137] In some embodiments, the top membrane 3 can comprise two first layer film 31, 31′ of PHA blended with one or more biopolymers that surround the second layer at least one PBS.

Example 1: Extraction of Coffee Beverages

[0138] A PHA biodegradable top membrane in accordance with the present invention comprising a PHA blend layer, a PBS layer, and a second PHA blend layer was prepared with a thickness of 150 μm and attached to a beverage capsule such as illustrated in FIG. 1. The body of the capsule was made of PHA. The beverage capsule was filled through the top membrane under high pressure (5-9 bars) with a long time extraction (25-30 seconds) coffee. The samples were prepared as for commercial coffee, including the usage of a heat sealing device to achieve heat sealing. The seal head was protected with a paper so that the top membrane does not stick.

[0139] No leak was observed even during beverage preparations with the longest extraction times and the highest pressures.

Example 2: Resistance to Burst Testing

[0140] As the extraction with coffee would bever deliver a pressure above 10 bars, a resistance to burst test was created to check at which pressure the top membrane would detach from the flange of the capsule.

[0141] The procedure for such a measurement comprises the following steps: a) placing the capsule to be tested in a bell under airtight conditions; b) introducing compressed air (6 bars) inside the bell and through the hole at the bottom of the capsule and measuring pressure inside the bell; the tested capsule can be empty (no opening means and bottom membrane) or, if there are the opening means and the bottom membrane, the air introduced through the bottom hole pierces easily the bottom membrane or wall; in both of these cases the results in terms of burst resistance of the top membrane are the same; and c) waiting for the bursting of the top membrane and measuring the corresponding pressure.

[0142] The results showed that a capsule such as defined in Example 1 with a 150 μm top membrane was able to withstand between 10 bars and 11 bars, while a comparable capsule with a 120 μm top membrane was able to withstand between 7 bars and 9 bars.