Portion capsule

Description

[0001] The invention relates to the preparation of beverages or the like from an extraction material contained in a capsule, for example, ground coffee. It particularly relates to a single-serve capsule.

[0002] Extraction devices for preparing beverages from a product contained in a single-serve container are known, for example, as coffee, espresso, or tea machines. In many such systems, the single-serve containers are designed as capsules, in which the product is sealed, for example, hermetically. For extraction, the capsule is pierced on two opposite sides. A brewing liquid—generally hot water—is introduced into the first side. The brewed product is expelled from the capsule on the second side. Depending on the beverage being prepared and the system, a considerable amount of pressure must be maintained inside the capsule.

[0003] WO 2010 / 118543, WO 2015 / 096989, and EP 3 907 145 A1 disclose single-serve coffee capsules that are approximately cube-shaped, made of plastic, and, unlike the known cup-shaped capsules, do not have a circumferential collar on the plane of one (top) cover surface. Such a circumferential collar is required in capsule systems according to the prior art, among other things, for sealing the capsule with a film serving as a lid. In contrast, WO 2010 / 118543, WO 2015 / 096989, and EP 3 907 145 use a domed lid. The capsule manufactured according to the teaching of WO 2010 / 118543 therefore has a welding brow forming a collar between the planes defined by the cover surface, the extent / lateral projection of which, however, is significantly reduced compared to the collar of known capsules.For welding, an energy director is required, which is formed by a circumferential rib and can be present on the cup (according to WO 2010 / 118543) or on the lid (according to WO 2015 / 096989). In the solution according to WO 2015 / 096989, the rib is formed by forming a circumferential groove (channel) on the lid from the top side (i.e., the side opposite the side with the energy director), e.g., using a deep-drawing process. The capsule according to WO 2015 / 096989 therefore has a circumferential groove for the purpose of forming the energy director. EP 3 907 145 proposes using a sonotrode with an energy director instead of an energy director in the form of a rib on the lid.

[0004] Aluminum and plastics, such as polypropylene, have become particularly well-known capsule materials. So-called bioplastics have also been discussed as capsule materials. On the one hand, these refer to plastics made from a renewable raw material (so-called bio-based plastics). On the other hand, bioplastics refer to plastics that are biodegradable (so-called biodegradable plastics). The plastics proposed for the production of portion capsules are biodegradable and sometimes contain a proportion of bio-based plastics.

[0005] In this text, "biodegradable" means biodegradable according to the EN13432 standard (as of end of 2020), and "biobased" means "made from renewable raw materials, not fossil-based".

[0006] Available bioplastics, especially biodegradable plastics, have the property that they soften at relatively low temperatures and thus exhibit a certain degree of flowability even at low temperatures (low glass transition temperature). However, they require relatively high temperatures to achieve complete flow (i.e., the melting temperature, as defined, is not particularly low). This presents particular challenges for welding, as a reliable weld requires a transition to a highly flowable state (as defined above the melting temperature). Therefore, the time period during which the material is essentially flowable is longer than with conventional plastics.

[0007] Plastic capsules of the type described in WO 2010 / 118543 and WO 2015 / 096989 have proven effective. However, their production involves a certain amount of effort. Furthermore, due to the sharp-edged ultrasonic tool described in WO 2015 / 096989, adequately protecting the diffusion barrier layer present in plastic capsules in the weld area presents a certain challenge.

[0008] It is therefore an object of the present invention to further improve the properties of capsules of this type, in particular with regard to manufacturability, and in particular with regard to usability with different materials, including bioplastics.

[0009] This problem is solved by the invention as defined in the patent claims.

[0010] A portion capsule filled with an extraction product for the production of a brewed product comprises, in a manner known per se, a plastic base body and a lid attached thereto. The base body forms a base region, a circumferential side wall, and a circumferential base body collar adjoining the circumferential side wall towards one side of the lid. The lid has a lid collar, the inside of which is welded to the base body collar, such that the base body collar and the lid collar together form a collar of the capsule. The base body and lid together form a capsule enclosing the extraction product. The capsule has a substantially rectangular, in particular square, outline, in that the base body has a substantially rectangular, in particular square, outline, at least in the area of ​​the collar.The collar has a plurality of ribs which are not parallel, i.e. at an angle to the side wall, and which run on the lid side.

[0011] The ribs serve the following function: During torsional welding—torsional welding is a well-known process that will not be described in detail here—they serve as a tool for engaging the cover, enabling rotational oscillations of the cover relative to the base body. This applies regardless of whether the ribs are created by this tool or in a separate step.

[0012] After the welding process, the ribs can contribute to the stability of the connection between the base body and the lid by structuring the weld. They thus have a stabilizing effect, particularly against shear forces between the base body and the lid.

[0013] It turns out that the combination of such ribs with torsional welding produces, firstly, good weld strength for many plastic materials, with minimal material deformation. A particularly advantageous feature is that this allows a wide variety of materials to be used for the capsule, including, in particular, bioplastics.

[0014] Secondly, any barrier layer remains intact. In plastic capsules, the barrier layer is a layer integrated into the wall, which increases the oxygen impermeability of the capsule compared to a structure made solely of the plastic (e.g., polypropylene or a bioplastic), thus eliminating the need for oxygen-tight outer packaging of the capsule. An example of a barrier layer material is EVOH (ethylene-vinyl alcohol copolymer). Such a barrier layer can, for example, be integrated inside the capsule material as a sandwich between plastic layers. A conventional plastic welding process using an energy director can locally destroy the barrier layer at the location of the energy director. The ribs and the torsional welding they enable avoid this disadvantage, while still maintaining the aforementioned stabilizing effect, particularly against shear forces.

[0015] Thirdly, there are also other manufacturing advantages, including shorter welding times.

[0016] One of the findings underlying the invention is that the aforementioned advantages of the ribs in the collar, which are partly related to torsional welding, also result in non-round but rectangular cross-sections, even though torsional welding is associated with rotational movements (rotational oscillations).

[0017] The number of ribs can be selected as required, although generally a larger number is present, for example at least 20 or at least 30, or at least 40 or even 60 or more. The maximum number can be, for example, 150 or 120 or 100, depending on the dimensions of the capsule. The width of the ribs and their spacing can be of a similar size so that they form a rib and groove pattern. For example, the average spacing between adjacent ribs can be less than or equal to five, four or three times their average width, so that the width of the groove between the ribs is no more than four, three or twice the width of the rib itself. The relative dimensions of ribs and the grooves between them do not have to be constant along the circumference of the capsule, but can also vary significantly, e.g.with ribs that are significantly wider than the grooves between them in the area of ​​the (rounded) corners of the collar and with ribs that are approximately the same width as the grooves or significantly less wide in the middle between the corners.

[0018] As mentioned, the ribs run at an angle to the sidewall and the collar, for example, approximately perpendicular. The ribs can run approximately radially, for example.

[0019] In this text, "radial" and "axial" always refer to the capsule's axis, which runs through the center of the capsule and perpendicular to the plane defined by the collar (and generally also to the plane of the capsule base and a cap). This axis is also related to the capsule's function: During brewing, the liquid flows axially, i.e., from the capsule base to the cap (or vice versa).

[0020] The ribs can run from the inside to the outside of the collar, up to a radial outer edge.

[0021] The ribs are present on the collar on the lid side, i.e., they are formed in the lid collar. However, they can also cause the weld itself—that is, the transition between the lid collar and the base body collar, as far as still defined—to acquire a certain rib-and-groove pattern (wave pattern), so that in addition to the material bond, a certain interlocking is also created, which contributes to the aforementioned additional stabilization.

[0022] As known per se from WO 2010 / 118543 and WO 2015 / 096989, the lid may not be flat, but rather curved outwards (with respect to the interior of the capsule), i.e., axially outwardly. This means that an axially end-side lid surface is offset axially outwards relative to the plane defined by the collar. According to these embodiments, the lid differs from a flat, e.g., film- or plate-like lid element. It is a three-dimensionally shaped body. The lid can be produced, in particular, by deep drawing or, alternatively, by injection molding, which also applies to the base body.

[0023] In such embodiments, the shape of the lid can comprise, from the outside to the inside, the lid collar, a curved transition area, and a central flat area that forms the actual upper cover surface. The transition area can, for example, be S-shaped or curve continuously from an outer section at an angle to the collar plane to the central flat area. The dimensions are selected, for example, such that the central flat area visually dominates, for example, by being the same size as or only slightly (e.g., a maximum of 10%) smaller than the base area. In particular, it can be provided that this flat area occupies more than 60% of the diameter and accordingly at least 40% of the area.

[0024] The lid collar will generally form a circumferential surface facing the lid side—with ribs, if present on the lid side—that extends from an outer edge of the collar to a base of the curvature. In some embodiments, the base of the curvature may be offset inward relative to the portion of the base body side wall to which the collar adjoins. Such an offset may, for example, be at least 0.2 mm.

[0025] In some embodiments, the base body and / or lid can be present, for example, as a multi-layer system with bioplastic (e.g., Ecovio) / PVOH / bioplastic, with PVOH forming the diffusion barrier layer. Particularly for thermoformable layer systems, a so-called tie layer, i.e., an adhesive layer, can be arranged between the PVOH layer and the bioplastic, so that the structure can then be bioplastic / tie / PVOH / tie / bioplastic. Biodegradable tie layers are now known and commercially available, for example, as natural waxes.

[0026] As an alternative to the bioplastic design, the base body and lid can also be made of another plastic - e.g. with a diffusion barrier layer - such as polypropylene.

[0027] The plastic material of the lid and the base body can be identical. However, it is also possible for the lid to be made of a different plastic composition, which can be welded to the base body plastic.

[0028] The wall thickness in the area of ​​the base body is, in particular, between 0.2 mm and 0.4 mm, for example, between 0.25 mm and 0.35 mm. The same can also apply to the wall thickness of the lid. In one embodiment, the wall thickness of the lid corresponds approximately to the wall thickness of the base body.

[0029] A special optional feature can be that the base body forms a thickened portion in the transition area between the circumferential side wall and the base body collar, forming a radially inwardly projecting bulge. This serves to stiffen the collar area.

[0030] The capsule can—this applies to all embodiments, including the first aspect—be designed in particular such that the base body and the lid together completely enclose the extraction material, without an opening covered, for example, by a film or the like. It can, in particular, be hermetic and oxygen-tight, for example, by having a suitable diffusion barrier.

[0031] Embodiments of the invention are described below with reference to drawings. In the drawings, like reference numerals designate like or analogous elements. The drawings are not to scale and show partially corresponding elements in different sizes from figure to figure. They show: Fig. 1 a capsule; Fig. 2 a base body for the production of a capsule according to Fig. 1 ; Fig. 3 a lid according to the state of the art, drawn in section; Fig. 4a view of a capsule according to the invention; and Fig. 5 a section through the capsule, shown only in part, in the area of ​​the welding.

[0032] Capsule 1 according to Figure 1 It is essentially cube-shaped with rounded edges. However, its dimensions increase slightly toward the top, so that, strictly mathematically speaking, the capsule has a truncated pyramid shape. The angle of inclination of the lateral surfaces in the figure relative to the perpendicular to the base surface 5—of course, this refers to the plane perpendicular to the base surface and passing through the edge between the base surface and the corresponding lateral surface—is very small, preferably no more than 2°, for example, only about 1°. Furthermore, the height of the capsule above the base surface approximately corresponds to the length of the base surface edges.

[0033] The capsule comprises a base body (or cup) 2 and a lid 3 attached thereto along a circumferential collar 4. The base body forms a capsule base 5 and a circumferential side wall 6, which is closed at its outer end in relation to the axial direction (axis 10), the upper end in the figure, by the collar 4. The lid is curved outwards in that the lid surface 9, which is essentially parallel to the capsule base 5, is curved outwards in comparison to the circumferential collar 4, i.e. Fig. 1 upwards, offset.

[0034] Figure 2 shows the base body 2 (cup) before filling and before closing. The base body collar 41 has an extension that can be larger than that of the collar 4 of the finished capsule.

[0035] Figure 3shows a lid 3, which—like the base body 2—is manufactured, for example, by deep drawing or, for example, by injection molding. The lid has a substantially flat central region 31, a transition region 32 forming a curvature, and a lid collar 42.

[0036] Capsules of Figure 1 drawn type, basic body 2 in the Figure 2 drawn type and cover 3 of the in Fig. 3 The type shown is already known from the prior art, for example from WO 2015 / 096990.

[0037] During capsule production, the base body 2 is first filled with the extraction material, and then the lid 3 is positioned. Ultrasonic welding then takes place, specifically torsional welding as is known from the prior art. Depending on the initial expansion of the base body collar and the lid collar, an optional trimming of the protruding collar section takes place after the welding process.

[0038] Figure 4shows an example of a capsule 1 according to the invention. It can be seen that the capsule has, in the region of the collar 4 on the top side - i.e. on the side of the lid collar, a plurality of ribs 50 with grooves 51 formed between them. The ribs 50 run radially with respect to the axis 10. Deviations from the radial direction are also conceivable - for example, the ribs 50 could run parallel to one another on each of the four sides and perpendicular to the capsule side wall. In any case, the orientation of the ribs is not parallel to the circumferential direction (not locally parallel to the side wall, i.e. at an angle to the plane which is defined locally by the side wall at the location of the corresponding rib), and also not parallel to the course of the collar. In particular, the ribs can each run from the radially inner to the radially outer end of the collar.

[0039] The ribs can be Figure 4As shown, the ribs can be arranged relatively close to one another so that their width and spacing are of a similar size, forming a rib-and-groove pattern. For example, the spacing between adjacent ribs (measured from their center) can be no greater than four or no greater than three times their width. However, arrangements with ribs spaced further apart are also conceivable.

[0040] Figure 5 shows a schematic cross-section through the capsule in the area of ​​the collar (in Figure 1 The welding between the base body 2 and the cover 3 is shown schematically by hatching. Fig. 5 that the diffusion barrier layer 70 extends to the radially outer end (in Fig. 5 far left) is essentially intact.

[0041] In addition, Fig. 5The following optional features are shown, which are advantageous for the stable connection between the base body and the lid: The shoulder 12 of the curvature of the lid is offset radially inward compared to the outer side of the circumferential side wall 6 (offset v). The offset v is relevant in comparison to the thickness of the capsule wall; in particular, it is at least 0.2 mm. The offset v is measured between the planes parallel to the outer surface of the base body in the region of the collar 4, which planes pass through the location of maximum concave curvature in the transition between the lid-side surface and the curvature of the lid or the outer surface of the base body. In the region of the transition between the circumferential side wall 6 and the base body collar 41, the base body forms a thickened portion 21 which forms a bead projecting radially inward. The material thickness of the base body is increased in the region of the base body collar compared to the circumferential side wall 6, i.e. the base body collar is thicker than the side wall. This also serves to stiffen it.

Claims

1. Portion capsule (1) filled with an extract for the production of a brewed product, comprising - a base body (2) made of plastic, with a bottom area (5), a surrounding side wall (6) and a surrounding base body collar (41) adjoining the surrounding side wall on the lid side; and - a lid (3) made of plastic, with a surrounding lid collar (42), wherein the lid is attached to the base body by welding an inner side of the lid collar to the base body collar so that a common collar (4) is formed; - wherein the base body and the lid enclose the extractable material; - the base body (2) having a substantially rectangular cross-section in the region of the collar (4); characterised in that - the collar (4) has a plurality of ribs (50) on an outer side, and in that - the ribs (50) extend in the collar on the lid side.

2. Portion capsule according to claim 1, wherein the ribs (50) extend at an angle to the side wall.

3. Portion capsule according to claim 2, wherein the ribs (50) extend radially with respect to an axis (10) which is perpendicular to a plane in which the collar (4) extends.

4. Portion capsule according to one of the preceding claims, wherein the ribs (50) extend to a radially outer end of the collar.

5. Portion capsule according to one of the preceding claims, wherein the lid (3) forms a curvature such that the lid contributes to a capsule volume and a lid surface (9) is offset relative to the collar (4).

6. Portion capsule according to claim 5, wherein the collar forms a circumferential surface (8) facing the lid side, which extends from an outer edge (7) of the collar (4) to a beginning (12) of the curvature, the beginning (12) of the curvature being offset inwards relative to a transition between the side wall (6) and the collar (4).

7. Portion capsule according to one of the preceding claims, wherein the lid (3) is produced by deep drawing.

8. Portion capsule according to one of the preceding claims, wherein the base body (2) is produced by deep drawing.

9. Portion capsule according to one of the preceding claims, wherein the lid (3) and the base body (2) are made of the same plastic.

10. Portion capsule according to one of the preceding claims, wherein the lid (3) and / or the base body (2) are made of a biodegradable plastic.

11. Portion capsule according to one of the preceding claims, wherein the lid (3) and the base body (2) feature a diffusion barrier layer (70), e.g. made of PVOH.

12. Portion capsule according to one of the preceding claims, wherein the base body (2) forms a thickening (21) in the area of a transition between the surrounding side wall (6) and the base body collar (41), where the thickening (21) forms a bead projecting radially inwards.

13. Portion capsule according to one of the preceding claims, wherein the number of ribs (50) is at least 20.

14. Portion capsule according to one of the preceding claims, wherein the distance between two adjacent ribs (50) is no more than three times the average width of the ribs (50).