BEVERAGE CAPSULE

Abstract

A capsule for use in a coffee machine having a brew chamber, which capsule is formed from a ductile metal such as aluminium. The capsule has a generally frusto-conical form with an upper surface and a lower surface, an annular flange being provided at the lower surface. An annular seal is provided on the annular flange having first and second layers, wherein the first layer comprises long, well-bound fibres of a cellulose material.

Claims

1. A capsule for use in a coffee machine having a brew chamber, which capsule has a generally frusto-conical form with an upper surface and a lower surface, an annular flange being provided at the lower surface, wherein an annular seal is provided on the annular flange comprising a cellulose material such as paper that deforms plastically in use, wherein the annular seal comprises first and second layers, wherein the first layer comprises long, well-bound fibres.

2. The capsule according to claim 1, wherein the second layer comprises an elastically compressible material.

3. The capsule according to claim 1, wherein the seal further comprises a layer for adhesive for attaching the seal to the capsule rim.

4. The capsule according to claim 1, wherein the first layer is formed from chemical (sulphate) pulp or CTMP (chemi-thermomechanical pulp).

5. The capsule according to claim 1, wherein the seal comprises a layer of a liquid heat sealable adhesive.

6. The capsule according to claim 3, wherein the adhesive is starch based biodegradable adhesive having a melt range around 140 degrees Celsius.

7. The capsule according to claim 1, wherein the seal is applied with pressure and/or heat without using an adhesive, wherein as pressure and/or the heat is applied the gasket swages out and tightens around the internal diameter of the seal to fix the seal in position on the capsule.

8. The capsule according to claim 1, wherein the seal is made from a non-coated board or only is only coated on one side and ink is applied to the non coated side.

9. The capsule according to claim 1, wherein a pattern is applied to a or the non coated side of the seal, which breaks up the print layer into small pieces, thereby allowing pressure to escape.

10. The capsule according to claim 8, wherein the seal is laminated over the top of the printed surface so that the ink is not in direct contact with the brew chamber of a coffee machine.

11. The capsule according to claim 1, wherein the edge wick is less than 5 mm in an edge wick test with Hot Water at 95° C. for 10 minutes.

12. The capsule according to claim 1, wherein the seal has a tear resistance of 3000-5000 mN and an internal bond strength of greater than or equal to 90 J/m2.

13. The capsule according to claim 1, wherein the seal is provided with an annular groove for receiving the capsule cage or brewhead of a coffee machine and thereby provide a sealing engagement.

14. The capsule according to claim 1, wherein the seal is provided with an annular protrusion for engaging with the capsule cage or brewhead of a coffee machine and thereby provide a sealing engagement.

15. The capsule according to claim 13, wherein the flange is provided with a corresponding groove or protrusion.

Description

[0017] Exemplary embodiments of the invention will now be described with reference to the drawings, in which:

[0018] FIG. 1a shows schematically a cross section of a capsule

[0019] FIG. 1b shows schematically a cross section of the capsule interfacing with machine blades

[0020] FIG. 1c shows schematically a brewhead of a coffee machine

[0021] FIG. 2 shows a perspective view of the capsule;

[0022] FIG. 3a shows a first layered seal

[0023] FIG. 3b shows a second layered seal

[0024] FIG. 4 shows a laminated structure of a seal

[0025] FIG. 5a shows schematically a first alternative structure

[0026] FIG. 5b shows scheamtically a second alternative structure

[0027] FIG. 1a shows a cross-section of capsule 1 having a generally frustoconical form for the main body 2. The upper end 3 of the capsule has a second frustoconical section 4 with a smaller diameter than the lower end. The upper end 3 is further provided with an additional frustoconical indent 5 at the centre of the upper end 3. The capsule is provided with a flange 7 at the end of main body 2 remote from the upper end 3.

[0028] To ensure that the capsule functions effectively in the wide range of capsule coffee machine on the market, the four dimensions marked V, W, X and Y are critical and need to be used if problems with the insertion and ejection of the capsule in the machines is to be avoided.

[0029] FIG. 1b shows a further dimension on the capsule, namely A, which is the distance between the capsule sealing surface to the surface of the capsule interfacing with the machine blades at the top of the capsule and FIG. 1c shows a dimension B, which is the distance between the coffee machine brew head or capsule cage sealing surface and the tip of the blade 20. Dimension A varies with the thickness of the seal on the flange, whereas dimension B is determined by the capsule coffee machine design. The piercing depth of the blades is deduced by subtracting Dimension B from Dimension A.

[0030] FIG. 2 shows a perspective view of the capsule, which is provided with an annular protruding surface 10 outwards from the upper surface. The protruding surface 10 is chamfered or inclined but could also be a radiused surface. The protruding surface 10 provides a steeper angle than the surface 4 to the blades, which improves the entry of the blade. The flange 7 comprises an upstanding wall 8, which thereby forms a gutter 9 between the wall of the capsule and the upstanding wall 8. The upstanding wall 8 then bends back down towards the same side as the opening such that the distal end is substantially in the longitudinal plane of the capsule but below the gutter 9. The shape of the distal end forms an open hook. The open hook receives a seal to close the capsule after packing or filling. The open hook shape provides a plurality of webs at the rim of the flange which provide a degree of reinforcement so that the foil can be easily attached to a capsule made of softer, more ductile materials such as aluminium.

[0031] The annular surface 10 is raised from the surrounding plane of the capsule surface 12 by between 0.15 and 0.35 mm and in a particularly preferred embodiment 0.25 mm. The surface has a width of around 0.2-0.3 mm, to allow for tolerances between machines. The angle of the surface to the planar surface of the capsule is between 30 and 34° with the angle increasing from the centre to the to the edge of the capsule. Within the range of heights of the protruding surface, the blades of the brew head maintain an incident angle of around 30° to the planar surface of the capsule 12. If the incident angle of the blades is greater than around 35° or less than around 25° there is a tendency for the capsule to deform under the action of the blades rather than be pierced. Within the ranges of the specific embodiments, a hole size of between 0.95 and 1.05 mm diameter can be achieved, which allows an optimal flow rate for a standard espresso grind.

[0032] A seal 9, having a generally annular form is provided on the flange with exemplary seal structures shown in FIGS. 3a, 3b and 4. Exemplary seals contain a layer of chemical (sulphate) pulp or CTMP (chemi-thermomechanical pulp) or 3 layers with a layer of chemical (sulphate) pulp and CTMP (chemi-thermomechanical pulp). The chemical pulping process produces long, well-bound fibres, which give the material high strength and water-resistant properties.

[0033] The material structure also provides good edge wick holdout. Edge wick defines a resistance to liquid penetration along the exposed edge of a board, which helps to maintain the strength and rigidity of the gasket in use.

TABLE-US-00001 PE: Exemplary Property Specification Thickness 200-595 (microns) Grammage (gsm) 150-550 Tear Resistance 3000-5000 (mN) Test method: ISO 1974 Internal Bond ≥90 Strength (J/m.sup.2) Test method: T 596 Moisture content 7.0%-8.5% Test method: ISO 287 Edge wick (mm) ≤5 mm wicking Test method: Hot distance. Water 95° C., 10 minutes

[0034] A further exemplary embodiment shown in FIGS. 3a and 3b is a hybrid laminate option in which the hybrid concept can be a laminate of elastic material (for example one of foam/plastic/silicon) and non elastic deformable material (i.e. paper). The lamination can be 2 or more layers where paper is the outer or upper layer so it plastically deforms.

[0035] Residual water in the brewhead causes a small amount of swelling of the paper or cellulose material when the coffee machine is in use, which swelling enables a better engagement with castellations on the brewhead thereby improving the seal.

[0036] The seal can be retained in position either by adhesive or a mechanical means.

[0037] In a first embodiment, the seal is fixed to the flange with an adhesive, in particular a starch based biodegradable adhesive having a melt range around 140 degrees, which is sufficiently above 100 degrees seen during coffee extraction, but low enough to activate during the short dwell time during capsule filling. Using an elevated sealing head temperature enables a temperature of 140 degrees to be reached in that short time.

[0038] In an alternative embodiment, the gasket can be applied with pressure and/or heat without using an adhesive. This could either be a dry heat process or it would be possible to use steam. As pressure and/or the heat is applied the gasket swages out and tightens around the internal diameter, creating a tight fit over the capsule. The outer diameter also increases, pushing the gasket against the rim of the capsule.

[0039] In a further alternative embodiment, it is possible to apply a liquid heat sealable adhesive directly to the board This can be used instead of adhering a film to the board would be help reduce cost and improve recyclability. The liquid heat sealable adhesive is applied in one or more coats. The first acts as a primer, the subsequent coat or coats are applied to build up a level of thickness that is on the surface, ensuring not all the adhesive has been absorbed into the board. An exemplary grammage for heat seal adhesive applied is 4 to 30 gsm.

[0040] For cosmetic reasons it is preferable to use a gasket that is colour matched to the capsule. The known approaches suffer from the problem that the gasket adheres to the Brew Chamber during/after extraction when the capsule is ejected. The reason for this is likely to be the inks soften when exposed to the heat and pressure and re-activate (soften). Then when cooling, the ink and gasket stick to the brew chamber. This can leave all or some of the gasket on the brew chamber, resulting in build-up which ultimately leads to leaks during extraction. The printed gasket may also prevent pressure release from gasket

[0041] In a preferred aspect the seal is made from a non-coated board or only on one side and ink is applied to the non coated side, for example to colour match the seal to the capsule body. This approach advantageously allows the ink to soak into the core of the board, making delamination less likely. Alternatively, it is possible to apply a pattern to the non coated side, which breaks up the print layer into small pieces, allowing pressure to escape. If delamination does start, the pattern reduces the likelihood of the delamination spreading. The pattern can comprise dots/hashed lines/wavy line etc. Aesthetically the pattern can be chosen so that the board looks fully printed.

[0042] This can be solved by laminating over the top of the printed surface as shown in FIG. 4, the ink is not in direct contact with the brew chamber. Therefore, even if it does re-activate, it cannot stick to the brew chamber.

[0043] The capsule wall is provided with flutes which extend over substantially the length of the side wall part 2 of the main body. The flutes are recessed by between 0.1 and 0.3 mm from the maximum outer radius of the side wall 2. The flute may be between 0.5 and 10 mm wide. The flutes may be substantially contiguously disposed in the side wall.

[0044] It has been surprisingly discovered that the provision of the flutes extending over a substantial part of the side wall 2 greatly increase the strength of the capsule, which becomes much less likely to deform. The fluted design capsule requires a force of 20N to deform the side of the capsule by 2.0 mm, whereas known capsules require a force of 10N to 15N. The force is applied using a 9.0 mm diameter pad, ⅓ up from the gasket sealing surface, in a direction normal to the axis of the capsule. This greatly improves the ease of handling the capsule both in the manufacture of the capsule and its filling. It is also less likely to be damaged in transit. This will reduce wastage in capsule production and facilitate the wider use of aluminium capsules which are preferable to plastic with respect to their recyclability.

[0045] In capsule of the invention the aluminium is between 0.075 to 0.125 mm thick.

[0046] FIG. 5a shows an alternative arrangement of the seal in which the annular seal 9 is provided with an annular groove or concave rib 15. A corresponding annular groove 16 is formed on the annular flange of the capsule. The annular groove 10 can receive the capsule cage of the coffee machine.

[0047] FIG. 5b shows an alternative arrangement to that of FIG. 5a, in which the seal is provided with an annular protrusion or convex rib 17. The annular flange is provided with a corresponding protrusion or rib 18. In use, the capsule cage of the coffee machine can engage on the protrusion to form a seal.

[0048] Although the capsule has been specifically described as being used to make espresso coffee, it would be possible to use the capsule to make other beverage capsules such as tea or chocolate.