Biodegradable Packaging Unit for a Food Product and Method for Manufacturing Such Packaging Unit

Abstract

The invention relates to a biodegradable packaging unit for a food product and a manufacturing method there for. The packaging unit comprises: —a container with an outer surface and an inner surface at least partly defining a compartment for holding the food product; —a biodegradable multi-layer that is provided on the inner surface of the container and comprising: —an inner cover layer comprising an amount of a biodegradable aliphatic polyester; —a first intermediate layer of a biodegradable material for connecting and/or sealing adjacent layers; —a functional layer comprising a polyvinylalcohol; —a second intermediate layer of a biodegradable material for connecting and/or sealing adjacent layers; and—an outer cover layer comprising an amount of a biodegradable aliphatic polyester, wherein the container comprises a moulded fiber matrix with an amount of biodegradable aliphatic polyester.

Claims

1. A biodegradable packaging unit for a food product, the packaging unit comprising: a container with an outer surface and an inner surface at least partly defining a compartment for holding the food product; a biodegradable multi-layer that is provided on the inner surface of the container and comprising: an inner cover layer comprising an amount of a biodegradable aliphatic polyester; a first intermediate layer of a biodegradable material for connecting and/or sealing adjacent layers; a functional layer comprising a polyvinylalcohol; a second intermediate layer of a biodegradable material for connecting and/or sealing adjacent layers; and an outer cover layer comprising an amount of a biodegradable aliphatic polyester, wherein the container comprises a moulded fiber matrix with an amount of biodegradable aliphatic polyester.

2. The biodegradable packaging unit according to claim 1, wherein the amount of biodegradable aliphatic polyester in the moulded fiber matrix is in the range of 0.1 to 12 wt % of the unit.

3. The biodegradable packaging unit according to claim 1, wherein the biodegradable aliphatic polyester in the moulded fiber matrix comprises fibers.

4. The biodegradable packaging unit according to claim 3, wherein the fibers comprise PBS and/or PBST and/or PBAT.

5. The biodegradable packaging unit according to claim 1, wherein the amount of non-fiber based material is below 25 wt %, preferably below 20 wt %, and/or further comprising an amount of natural and/or alternative fibers.

6. The biodegradable packaging unit according to claim 1, wherein one or more of the intermediate layers of biodegradable material comprise a biodegradable aliphatic polyester.

7. The biodegradable packaging unit according to claim 1, further comprising a cover or lid for sealing the compartment, wherein the cover or lid comprises the biodegradable multi-layer comprising: an inner cover layer comprising an amount of a biodegradable aliphatic polyester; a first intermediate layer of a biodegradable material for connecting and/or sealing adjacent layers; a functional layer comprising a polyvinylalcohol; a second intermediate layer of a biodegradable material for connecting and/or sealing adjacent layers; and an outer cover layer comprising an amount of a biodegradable aliphatic polyester.

8. The biodegradable packaging unit according to claim 7, wherein the cover or lid further comprising a paper layer.

9. The biodegradable packaging unit according to claim 8, wherein the cover or lid further comprising a second paper layer, and/or wherein the paper layer comprises an opening for a window.

10. (canceled)

11. The biodegradable packaging unit according to claim 1, wherein the biodegradable multi-layer comprises at least two functional layers.

12. The biodegradable packaging unit according to claim 11, wherein the at least two biodegradable multi-layers are separated by a layer of a biodegradable aliphatic polyester.

13. The biodegradable packaging unit according to claim 1, wherein the thickness of the biodegradable multi-layer is in the range of 20 to 150 μm.

14. (canceled)

15. The biodegradable packaging unit according to claim 1, wherein the functional layer is positioned asymmetrically in the multi-layer.

16. The biodegradable packaging unit according to claim 1, wherein the laminated multi-layer comprises a colouring agent that is biodegradable and more preferably compostable.

17. (canceled)

18. The biodegradable packaging unit according to claim 1, wherein the matrix comprises an amount of calcium carbonate, wherein the matrix preferably comprises a mixture of micro fibrillated cellulose and calcium carbonate, preferably with an amount of 5 to 10 wt % of the matrix.

19. A method for manufacturing a biodegradable packaging unit for a food product, the method comprising the step of: providing a container with an outer surface and an inner surface at least partly defining a compartment for holding the food product; and providing a biodegradable multi-layer that is provided on the inner surface of the container and comprising: an inner cover layer comprising an amount of a biodegradable aliphatic polyester; a first intermediate layer of a biodegradable material for connecting and/or sealing adjacent layers; a functional layer comprising a vinyl alcohol polymer; a second intermediate layer of a biodegradable material for connecting and/or sealing adjacent layers; and an outer cover layer comprising an amount of a biodegradable aliphatic polyester, wherein the container comprises a moulded fiber matrix with an amount of biodegradable aliphatic polyester.

20. The method according to claim 19, wherein providing the biodegradable multi-layer comprises the step of co-extruding the layers, and/or wherein the biodegradable laminated multi-layer is melted or fused with at least a part of the inner surface of the packaging unit.

21. (canceled)

22. The method according to claim 19, further comprising the step of providing a cover or lid, wherein the cover or lid comprises a biodegradable multi-layer comprising: an inner cover layer comprising an amount of a biodegradable aliphatic polyester; a first intermediate layer of a biodegradable material for connecting and/or sealing adjacent layers; a functional layer comprising a polyvinylalcohol; a second intermediate layer of a biodegradable material for connecting and/or sealing adjacent layers; and an outer cover layer comprising an amount of a biodegradable aliphatic polyester.

23. The method according to claim 19, further comprising the step of performing (dry) sterilisation and pasteurisation of the packaging units, and/or further comprising the step of biodegrading the packaging unit, and/or further comprising the step of adding an amount of natural fibers.

24.-27. (canceled)

28. A biodegradable packaging unit for a food product, the packaging unit comprising: a container with an outer surface and an inner surface at least partly defining a compartment for holding the food product; and a biodegradable multi-layer that is provided on the inner surface of the container and comprising: an inner cover layer comprising an amount of a biodegradable aliphatic polyester; a first intermediate layer of a biodegradable material for connecting and/or sealing adjacent layers; a functional layer comprising a polyvinylalcohol; a second intermediate layer of a biodegradable material for connecting and/or sealing adjacent layers; and an outer cover layer comprising an amount of a biodegradable aliphatic polyester, wherein the container comprises a moulded fiber matrix with an amount of biodegradable aliphatic polyester, wherein the amount of biodegradable aliphatic polyester in the moulded fiber matrix is in the range of 0.1 to 12 wt % of the unit, and wherein one or more of the intermediate layers of biodegradable material comprise a biodegradable aliphatic polyester.

Description

[0113] Further advantages, features and details of the invention are elucidated on the basis of preferred embodiments thereof, wherein reference is made to the accompanying drawings, in which:

[0114] FIG. 1A shows a packaging unit for margarine having a packaging unit according to the present invention;

[0115] FIG. 1B-C show different embodiments of a multi-layer barrier layer for a packaging unit according to the invention;

[0116] FIG. 1D-E show different embodiments of a multi-layer barrier layer with one or more paper layers for a packaging unit according to the invention;

[0117] FIG. 2A shows an alternative packaging unit according to the present invention;

[0118] FIG. 2B shows a plate as food receiving product according to the invention;

[0119] FIG. 2C shows a food tray according to the invention having a paper layer with window;

[0120] FIG. 2D shows a container for coffee milk having a packaging lid element according to the invention as a foil;

[0121] FIGS. 3A and 3B show a packaging unit with laminated layer configured for receiving a food product according to the present invention;

[0122] FIG. 4 shows a container for yoghurt according to the invention;

[0123] FIG. 5 shows a meat dish as a packaging unit according to the invention;

[0124] FIG. 6 shows an ice cup cover as alternative packaging unit according to the invention;

[0125] FIG. 7 shows a sip lid according to the invention;

[0126] FIG. 8 shows a coffee capsule according to the invention;

[0127] FIG. 9A-D show egg packages units according to the invention comprising a multi-layer; and

[0128] FIG. 10 shows a bottle divider according to the present invention.

[0129] Packaging unit 2 (FIG. 1A) relates to a container for margarine or other products. Container 2 has bottom part 4 and side walls 6 defining compartment 7 and opening 8. Before use, opening 8 is covered with cover or seal 9 comprising a biodegradable laminated multi-layer 10. In this embodiment there is provided a separate lid 12.

[0130] In the illustrated embodiment container 2 is provided with peelable cover or seal 9. Edge 14 of cover or seal 9 is peeled from edge 16 of container 2. In this embodiment multi-layer 10 comprises a number of layers as transparent film and a paper layer. It will be understood that layers can also be provided as non-transparent, or alternatively as semi-transparent and/or partly transparent. Alternatively, container 2 can also be provided only with cover or seal 9 and without cover 12. This may also be applied to other type of packaging units, for example to in instant or ready-to-eat meals, such that conventional sleeves can be omitted from the packaging units. This enables a more cost-efficient packaging unit with a possible weight reduction.

[0131] Container 2 is manufactured from a moulded pulp material and optionally comprises an additional film layer of biodegradable aliphatic polyester, such as PBS and/or PLA and/or PBST and/or PBAT, on the inner surface and comprises an amount of biodegradable aliphatic polyester that is blended into the moulded pulp. This renders bottom part 4 and/or walls 6 water or liquid repellent and/or improves the heating step to melt or fuse laminated multi-layer 10 on or to edge 16. One of the further advantages of the use of biodegradable aliphatic polyester is the reduction or prevention of the liquid entering or migrating into the material during use. Another advantage is the constancy of size or dimensional stability. Furthermore, denesting properties are improved. Container 2 can be used for different products. For example, container 2 is capable of holding an amount of margarine or ice cream.

[0132] Optionally, fibers 18 are included in the matrix of container 2. This improves the possibilities for giving the unit a natural paper feel and/or look. This may also be applied to other type of packaging units.

[0133] Biodegradable cover or seal 9 comprises a laminated multi-layer 10 (FIG. 1B) comprising first cover layer 10a, first intermediate layer 10b, central functional layer 10c, second intermediate layer 10d, and second cover layer 10e. It will be understood that other layers can be added to multi-layer 10. It will be understood that laminated multi-layer 10 can be applied to container 2 and/or other packaging units that are illustrated or are not illustrated.

[0134] An alternative biodegradable cover or seal 9 with a laminated multi-layer 20 (FIG. 1C) comprises first cover layer 20a, first intermediate layer 20b, first functional layer 20c, second intermediate layer 20d, central flexible layer 20e, third intermediate layer 20f, second functional layer 20g, fourth intermediate layer 20h, and second cover layer 20i. It will be understood that other layers can be added to multi-layer 20. It will be understood that laminated multi-layer 20 can be applied to container 2 and/or other packaging units that are illustrated or are not illustrated.

[0135] In an alternative embodiment (FIG. 1D) multi-layer 10, 20 comprises paper layer 10f, 20j. In a further alternative embodiment (FIG. 1E) multi-layer 10, 20 comprises additional second paper layer 10g, 20k. In this embodiment paper layers 10f, 20j, and 10g, 20k provide a sandwich type configuration for multilayers 10a-e, 20a-i.

[0136] Packaging unit 22 (FIG. 2A) provides a further embodiment of a food receiving container having bottom part 24 and side walls 26 defining compartment 27 and opening 28. Packaging unit 22 has length L, width W and height H. On the inside of container 22 there is provided laminated multi-layer 30, optionally comprising a print. In the illustrated embodiment laminated multi-layer 30 is provided on the inside of packaging unit 22 and extends from bottom part 24 up to contour or edge 32. Contour or edge 32 is provided a small distance from the upper side of edge 34. This distance is preferably in the range of 1 to 12 mm Edge 34 is provided with width W1 that defines contact surface 36 for connecting to liner or seal 33 that is schematically illustrated. In the illustrated embodiment this liner or seal 33 is connected directly to the moulded pulp material, optionally with an adhesive, in stead of being connected to laminated multi-layer 30. Such adhesive preferably comprises an amount of biodegradable polyester, for example PLA and/or PBS and/or PBST and/or PBAT. Width W1 is in the illustrated embodiment in the range of 1 to 15 mm, preferably in the range of 2 to 5 mm.

[0137] In the illustrated embodiment packaging unit 22 (FIG. 2A) comprises first denesting elements 38 and second denesting elements 40. In the illustrated embodiment denesting elements 38, 40 enable denesting of a stack of packaging units 22. It will be understood that alternative denesting elements can also be envisaged in accordance with the present invention as alternatives or in combination.

[0138] In the illustrated embodiment, optional cover or top seal film 42 is preferably provided from laminated multi-layer 10, 20 with paper layer 10f, 20j.

[0139] Packaging unit 22 (FIG. 2A) has numerous applications, including but not limited to, airplane meals. Such meals are provided to the airplane after (dry) sterilisation and pasteurisation. In combination with the oxygen (O.sub.2)-barrier properties of the (laminated) multi-layer (and top seal film) the shelf-life of the food product is significantly improved. In addition, the oxygen (O.sub.2)-barrier prevents or at least reduces oxidation processes in the food and thereby contributes to the maintenance of food taste.

[0140] In another embodiment of a packaging unit according to the invention, plate 52 (FIG. 2B) is on the food receiving side provided with (laminated) multi-layer 53, for example an aforementioned multi-layer 10, 20. In the illustrated embodiment bottom or back side 54 of plate 50 is not provided with such (laminated) multi-layer 53. Optionally, plate 50 is provided with cover or top seal film 56, for example in case of plate 50 holding a salad or soup. It will be understood that also other food products can be contained by plate 50.

[0141] Food tray 62 (FIG. 2C) comprises bottom part 64 and side walls 66 defining compartment 67 configured for receiving and holding a product, and opening 68. Before use, opening 68 is covered with cover 70 comprising a biodegradable (laminated) multi-layer 72.

[0142] In the illustrated embodiment container 62 is provided with peelable cover 70. Edge 74 of cover 70 is peeled from edge 76 of container 62. In this embodiment cover 70 comprises a number of layers 10a-e, 20a-i, including a transparent film and paper layer 10f, 20j. It will be understood that layers can also be provided as non-transparent, or alternatively as semi-transparent and/or partly transparent. In the illustrated embodiment paper layer 10f, 20k is provided with opening 78 enabling a consumer to inspect the contents of compartment 67.

[0143] Inner surface 80 of packaging unit 62 comprises PBS and/or PLA and/or PBAT and/or PBST material that is blended and/or integrated with the fibres of the moulded pulp material in the matrix. Optionally, the material is provided as additional film layer. In the illustrated embodiment container 62 is manufactured from a moulded pulp or fluff pulp material, optionally comprising an amount of natural fibers. This improves the possibilities for giving packaging unit 62 a natural paper feel and/or look. This may also be applied to other type of packaging units. For example, in instant or ready-to-eat meals, such that conventional sleeves can be omitted from the packaging units. This enables a more cost-efficient packaging unit with a possible weight reduction.

[0144] Container 82 (FIG. 2D) for holding coffee milk comprises bottom part 84 and side walls 86 defining compartment 87 with opening 88. Before use, opening 88 is covered with cover or seal 90 comprising a biodegradable laminated multi-layer, preferably according to one of the embodiments illustrated in FIGS. 1B-E. In the illustrated embodiment container 82 is provided with peelable cover 90. Edge 92 of cover 90 is peeled from edge 94 of container 82.

[0145] Packaging unit 102 (FIG. 3A) relates to a food receiving container having bottom part 104 and side walls 106 defining compartment 107 and opening 108. On the inside of container 102 there is provided (laminated) multi-layer 110 comprising a compostable/biodegradable vinyl alcohol polymer. In the illustrated embodiment layer 110 comprises print 112. Preferably, in the illustrated embodiment the print is provided on the back side of laminated multi-layer 110.

[0146] In the illustrated embodiment container 102 is provided with peelable cover/top seal film 113a (FIG. 3A). Edge 113b is shown as peeled from edge 113c of container 102. In this embodiment top seal film 113a is shown as transparent film. It will be understood that film 113a can also be provided as non-transparent, or alternatively as semi-transparent and/or partly transparent. Alternatively container 102 can also be provided without top seal film 113a.

[0147] In an illustrated embodiment, laminated multi-layer 110 (FIG. 3B) comprises a food oriented side 114 and a packaging side 116. In the illustrated embodiment parts 118 can be removed or cut from sheet or layer 110 to dimension laminated multi-layer 110 according to the specifications and enable providing layer 110 into the inside of container 102. This enables positioning laminated multi-layer 110 correctly relative to corners 120. In this illustrated embodiment print 112 is provided in a mirror image on package side 116 of laminated multi-layer 110 to render the render print 112 visible for a user or consumer.

[0148] Container 202 (FIG. 4) for holding a food product such as yoghurt comprises bottom part 204 and side walls 206 defining compartment 207 with opening 208. Before use, opening 208 is covered with packaging element 210 comprising a biodegradable laminated multi-layer 210.

[0149] In the illustrated embodiment container 202 is provided with peelable cover 210. Edge 214 of packaging element 210 is peeled from edge 216 of container 202. In this embodiment packaging element 210 comprises a number of layers similar to multi-layer 10, 20, optionally including a transparent film and paper layer. It will be understood that layers can also be provided as non-transparent, or alternatively as semi-transparent and/or partly transparent.

[0150] Packaging unit 302 (FIG. 5) for holding meat 301 comprises bottom part 304 and side walls 306 defining compartment 307 with opening 308. Bottom part 304 comprises a number of protrusions or spikes 303. In the illustrated embodiment meat 301 rests on foil 309 and is covered by cover/seal 310 having a number of layers that are preferably transparent. Lower foil 309 also comprises a number of layers and/or comprises an absorbent material.

[0151] A further example in accordance with the present invention is cover 402, for example for an ice cup (FIG. 6) that is provided with (laminated) multi-layer 401. Another example of a packaging unit according to the invention is sip lid 502 (FIG. 7) that is provided with (laminated) multi-layer 501. Multi-layers 401, 501 are preferably similar to multi-layer 10, 20 that was already illustrated. Cover 402 and sip lid 502 comprise an additional film layer of biodegradable aliphatic polyester and and/or may comprise an amount of biodegradable aliphatic polyester that is blended into the moulded pulp. This renders cover 402 and sip lid 502 water or liquid repellent and/or improves the heating step to melt or fuse laminated multi-layer 401, 501 on or to cover 402 and/or sip lid 502. One of the further advantages of the use of biodegradable aliphatic polyester is the reduction or prevention of the liquid entering or migrating into the sip lid material during use. Another advantage is the constancy of size or dimensional stability. In this specific case this prevents sip lid 502 loosening from a cup or beaker for hot beverages such as coffee, tea or soup, or cold beverages such as carbonated drinks, and cup 402 from loosing from an ice cup, for example. It will be understood that such lids 502 can also be applied to other food containers. For example, lids 502 can be applied to containers for milkshakes, for example. Further details and examples of lids 502 are disclosed in WO 2010/064899, including embodiments with specific flanges and notches.

[0152] Sip lid 502 is preferably coated with a biodegradable aliphatic polyester liner, such as a PBS and/or PBAT and/or PBST liner in addition to (laminated) multi-layer 501 to improve the melting properties. As mentioned, sip lids 502 can be used for cups and milkshakes. Also, sip lids can be applied to so-called ready meal trays (for example, for pizza, wraps, fish, meat, lobster, pasta) and act as a (digital) printable and barrier seal, for example.

[0153] In an alternative embodiment packaging unit 602 relates to a coffee capsule (FIG. 8) and is provided with 604 and side walls 606 defining compartment 607 with opening 608. On the inside of container 602 there is provided (laminated) multi-layer 610 comprising a compostable/biodegradable vinyl alcohol polymer, preferably similar to multi-layer 10, 20. Compartment 607 holds a compound for dispensing beverages such as tea, coffee, soups etc. In the illustrated embodiment capsule 602 is provided with peelable cover/top seal film 612 that preferably comprising a multi-layer, preferably similar to multi-layer 10, 20 and not necessarily with the same configuration and/or composition as multi-layer 610. For example, cover 612 may comprise a multi-layer with more or less layers as compared to multi-layer 610 of compartment 607. Cover 612 is provided with sufficient strength to prevent undesired breaking in storage, transport and in the machine. Such sufficient strength guarantees sufficient seal integrity.

[0154] In use, capsule 602 is punctured to enable penetration of water with a temperature of 90 to 95° C. and a pressure that may be in the range of 10 to 15 bar. Brewing may take 20 to 25 seconds, for example. Multi-layer 610 prevents penetration of coffee into the matrix of compartment 607. Optionally, rim or ring 614 is provided to increase strength and/or denesting properties including removal from the machine. In the illustrated embodiment rim 614 is provided at or close to opening 608 of compartment 607.

[0155] Packaging unit 702 (FIGS. 9A and 9B) carries or holds eggs and comprises cover part 704 and bottom part 706. In the illustrated embodiment packaging unit 702 comprises laminated multi-layer 701. Multi-layer 701 is preferably similar to multi-layer 10, 20 that was already illustrated. Bottom part 706 is provided with back surface 708, sides 710 and front surface 712, and bottom surface 714. Cover part 704 is provided with back surface 716, side surfaces 718, front surface 720 and top surface 722. In the illustrated embodiment transition 724 is provided between top surface 722 and back and front surfaces 716, 720.

[0156] In the illustrated embodiment, top surface 722 of cover part 704 is provided with groove 726 comprising a number of openings 728. Openings 728 are defined by two adjacent arch-shaped edges 730, 732 having a larger thickness as compared to the average thickness of cover part 704.

[0157] Side surfaces 718 of cover part 704 are provided with denest nocks or denest elements 734. In the illustrated embodiment, bottom part 706 is provided with similar elements 736 mirroring denest elements 734. Hinge 738 connects back surface 716 of cover part 704 with back surface 708 of bottom part 706. Lock 740 comprises nose-shaped lock element 742 that is connected to flap 744 of bottom part 706. Cover part 704 is provided with openings 746 that capture lock elements 742 therewith defining lock 740.

[0158] In the illustrated embodiment, bottom part 706 is provided with a number of product receiving compartments 748, cones 750 and separating walls 752. Cone 750 extends from the bottom of bottom part 706 in an upward direction. Cover part 704 comprises cone support 754. Inner surface 758 of packaging unit 702 comprises PBS and/or PLA and/or PBAT and/or PBST material, optionally as film layer or alternatively blended and/or integrated with the fibres of the moulded pulp material. It will be understood that other configurations can also be envisaged in accordance to the invention. Packaging unit 702 may also be configured to receive other products, such as tomatoes, kiwis.

[0159] It will be understood that other designs for packaging units in accordance with the invention can be envisaged. For example, containers 780, 790 (FIGS. 9C and D) illustrate different designs for egg cartons capable of holding eggs P and comprise (laminated) multi-layer 781, 791. Multi-layers 781, 791 are preferably similar to multi-layer 10, 20 that was already illustrated.

[0160] As a further example, bottle divider 902 (FIG. 10) is illustrated with laminated multi-layer 901. Multi-layer 901 is preferably similar to multi-layer 10,20 that was already illustrated. Also, bottle divider 902 may comprise an additional film layer of PBS (and/or appropriate alternative biodegradable aliphatic polyester such as PBST and/or PBAT) and/or may comprise an amount of PBS and/or PBST and/or PBAT that is blended into the moulded pulp.

[0161] It will be understood that other types of food packaging units and/or packaging elements can also be envisaged in accordance with the present invention. Other examples of food packaging products may relate to cup carriers, cups, plates and other table ware etc.

[0162] In the manufacturing process of a packaging unit a moulded pulp material is prepared. An amount of biodegradable aliphatic polyester, such as PBS and/or PHBH, is blended or mixed into the moulded pulp material. Optionally, an amount of biodegradable aliphatic polyester, such as PBS and/or PHBH and/or PLA and/or PBST and/or PBAT is included in a separate layer that is provided in or on the packaging unit. Preferably, the laminated multi-layer is co-extruded with the moulded pulp material and deep-drawn. In addition, or as an alternative, the raw unit is moulded. Optionally, the raw unit is dried in the mould applying an in-mould drying process. In such alternative embodiment laminated multi-layer can be provided in the mould and a heating step is performed. Optionally, an additional layer of biodegradable aliphatic polyester is provided to improve the contact between the packaging unit and the laminated multi-layer. Finally, the product is released from the mould. Several post-drawing or post-moulding operations may optionally be performed in relation to the packaging unit. Preferably, the manufacturing method provides a relatively smooth outer surface (as compared to the inner surface). This improves possibilities for decoration, such as printing. Furthermore, this also improves denesting properties, including capsule release from the machine.

[0163] Several experiments have been performed with the illustrated packaging units. In several experiments an amount of a biodegradable aliphatic polyester was added to the moulded pulp material and a refining step was performed. Measurements were performed at a temperature of about 23° C. and a relative humidity of about 50%. Measurements involved a compression test. This showed a significant improvement in compression value. For example, a packaging unit with 7.5% PLA and/or PBS and/or PBST and/or PBAT and a refining step showed a compression value of 450 to 500 N, while for a similar conventional product under the same conditions this value is about 180 N. Even a sub-optimal conditions of relative humidity (RH) about 90% the compression value for the packaging unit according to the invention was about 250 to 270 N, thereby still outperforming the conventional product at its optimal conditions.

[0164] In a further test the multi-layer was applied to the food packaging unit with multi-layer 20 and for 24 hours exposed to 23° C. and a relative humidity of about 50%. No significant undesired oxygen penetration, referred to as the oxygen transfer rate (OTR), was detected. In fact, oxygen penetration was below 0.08 ml/m.sup.2 day.

[0165] Further experiments in relation to the OTR were performed on several samples at a temperature of about 23° C. and a relative humidity of about 50%. Different multi-layers were tested. Samples in accordance with multi-layer 10 having one functional layer were tested having PBAT-PLA or PBAT cover layers and a GPolymer functional layer (thickness of 4 or 6 μm) and a total thickness of about 100 μm or about 120 μm, respectively. Also, samples in accordance with multi-layer 20 having two functional layers were tested having PBAT-PLA or PBAT cover layers and two GPolymer functional layers (thickness of 2×2 or 2×3 or 2×4 μm) and a total thickness of about 80 μm, about 100 μm, about 120 μm, or about 150 μm, respectively, and a (central) flexibility layer of a blend of biopolymers, such as PBS, PBAT and/or PBST. Also, as mentioned, these samples showed an OTR below 0.08 ml/m.sup.2 d, and even below 0.05 ml/m.sup.2 d, which was the lowest test limit in this experiment. These experiments confirmed an OTR below 1 ml/m.sup.2 d, and even below 0.1 ml/m.sup.2 d, is achieved. Optionally, the inner and outer cover layers are provided with different thicknesses.

[0166] In a further test pressure was increased to about 15 and about 20 bar. Multi-layers 10, 20 remained their integrity and barrier properties. This is relevant for coffee capsule 602, for example.

[0167] Further tests related to the water vapor transmission rate (WVTR). Several biofilms with multi-layer 10, 20 were tested. In Table 1 some experimental results are included. Tests were performed at a temperature of about 23° C. and a relative humidity of about 50%. In the table results are shown for two samples of the same composition.

TABLE-US-00001 TABLE 1 WVTR measurements measurement Biofilm measurement type PBS cover and GPolymer (thick) below 3000 mg/m.sup.2 d Aquatran PBS cover and GPolymer (thick) below 3000 mg/m.sup.2 d Aquatran PBS cover and GPolymer (thin) 3000-3500 mg/m.sup.2 d Aquatran PBS cover and GPolymer (thin) 3000-3500 mg/m.sup.2 d Aquatran PBAT-PLA cover and GPolymer 2000-2500 mg/m.sup.2 d Aquatran PBAT-PLA cover and GPolymer 2000-2500 mg/m.sup.2 d Aquatran Cover only: Blend PBAT and PLA around 20 g/m.sup.2 d Permatran (indicative value)* Cover only Blend PBAT and PLA around 20 g/m.sup.2 d Permatran (indicative value)*

[0168] Results show that water vapor transmission can be reduced significantly as compared to conventional materials that show water vapor transmission rates of up to 200 g/m.sup.2 d. This shows that a biodegradable packaging unit can be applied to food products, including beverages and compounds for dispensing beverages such as tea, coffee, and soups. Also, at higher temperatures and pressures the transmission rate remains functional. Due to the fact that the functional layer of the biofilm is protected on both sides by a thin intermediate (tie) layer of PBAT (biopolyester) these layers avoid that the functional layer of GPolymer gets affected by water. This supports the good WVTR barrier properties of the entire film composition. This shows the applicability of the multi-layer for use in coffee capsules, for example. Furthermore, the low water vapor transmission rate that is achieved also reduces the loss of aroma due to a high WVTR. Also this is relevant for food packaging units, including coffee capsules.

[0169] Other tests related to other properties of the packaging unit, such as denesting. Providing an amount of 2 to 5 wt % of biodegradable aliphatic polyester in the moulded fiber matrix showed good denesting properties form a stack and/or external holder over a broad range of conditions, including a RH in the range of 50 to 90%, temperature of 23° C. to about 50° C., and pressures up to about 20 bar.

[0170] The present invention is by no means limited to the above described preferred embodiments thereof. The rights sought are defined by the following claims, within the scope of which many modifications can be envisaged.