Method for manufacturing a portioned capsule and portioned capsule

Abstract

The invention relates to a method for producing a capsule, comprising the following steps: providing a base body (2) made of plastic, having a base area (5), a circumferential side wall (6) and a circumferential base body flange (41) adjoining the circumferential side wall; providing a lid (3) made of plastic; filling the base body (2) with extraction material; placing the lid (3) on the base body (2) such that a fastening portion of the lid lies flat on the base body flange (41); and fastening the lid flange to the base body flange by means of ultrasonic welding. In the fastening of the lid flange, an inner surface (33) of the fastening portion lies flat on a flange surface (43) of the base body flange. An ultrasonic welding electrode (50) which is subjected to mechanical vibrations and has an energy director (52) is pressed against an outer surface (34) of the fastening portion or the base body flange such that the action of the mechanical vibrations causes the plastic material of the lid or the plastic material of the base body flange to begin to liquefy at the outer surface.

Description

[0001] This invention relates to the preparation of beverages from extractive materials present in capsules, such as ground coffee. In particular, this invention relates to a method for manufacturing capsules filled with extractive materials, and capsules manufactured by said method.

[0002] Extraction devices used to prepare beverages from extractable materials present in repackaged containers, such as coffee machines, espresso machines, or tea machines, continue to enjoy increasing popularity. For example, in many such systems, the repackaged container is implemented as a capsule, in which the extractable material is sealed in an airtight manner. For extraction, the capsule is punctured on opposite sides. A dispensing liquid—generally hot water—is introduced into the first side. The prepared product is expelled from the capsule from the second side. Depending on the beverage to be prepared and the system, a considerable pressure must be present inside the capsule. Instead of systems where the repackaged capsule is punctured, there are also systems with capsules already perforated, the perforations covered by a protective film, which, for example, is removed or dissolved before the preparation process.

[0003] Aluminum and plastics such as polypropylene have been specifically considered as capsule materials. Aluminum capsules offer excellent stability (flavor protection) for the extracted material, but their manufacturing is very energy-intensive. Polypropylene capsules have advantages in terms of energy requirements and disposal, but the requirements for puncture mechanisms and flavor protection are increased. Both aluminum and plastics have been criticized as capsule materials, the former due to the high energy consumption in manufacturing, and the latter particularly due to issues of waste.

[0004] A coffee dispensing capsule is known from WO 2010 / 118543, comprising a generally cubic shape made of plastic, and unlike known cup-shaped capsules, it does not include a flange on a plane of a (top) cap surface. This circumferential flange is necessary for capsule systems according to the prior art, due to the sealing of the capsule by means of a membrane serving as the cap, and for other reasons. When sealing is performed by means of ultrasonic welding, the flange is necessary to accommodate an energy guide. If the capsule is sealed by means of heat sealing, then the flange is necessary so that the cap contacts over a sufficiently large area. In contrast, according to WO 2010 / 118543, a dome cap is used, and sealing is performed, for example, by means of ultrasonic cutting and welding. Thus, capsules manufactured according to the teachings of WO 2010 / 118543, regardless of their (“cubic”) shape, have a circumferentially welded ridge forming a minimal flange only between the planes defined by the cap surface; however, the extension and lateral protrusion of this circumferentially welded ridge are significantly reduced compared to the flanges of known capsules.

[0005] So-called bioplastics have also been discussed as capsule materials. Plastics made from renewable resources are referred to as such (so-called bio-based plastics). Bioplastics are also biodegradable plastics (so-called biodegradable plastics). The proposed plastics for manufacturing refill capsules are biodegradable and partially contain a portion of bio-based plastics.

[0006] In this article, "biodegradable" means biodegradable according to EN13432 (version: end of 2019), and "bio-based" means "made from renewable resources rather than petrochemical-based".

[0007] Available bioplastics, particularly biodegradable plastics, have the following properties: they soften at relatively low temperatures, thus possessing a certain degree of fluidity at low temperatures (low glass transition temperature), but must be heated to relatively high temperatures (i.e., melting points, if defined, are not particularly low) before becoming fully flowable. This presents a particular challenge for welding, as the transition to a highly flowable state (above the melting point, if defined) is a prerequisite for reliable welding, thus the time span for the material to become substantially flowable is longer than that of conventional plastics.

[0008] Therefore, in order to manufacture capsules, a particular challenge arises for capsules that do not have a sealing film as a cap, but rather a plastic body with a three-dimensional shape as a cap, for example, especially for capsules with the shape described in WO 2010 / 118543 or, for example, WO 2015 / 096990.

[0009] The object of the present invention is to improve the method for manufacturing capsules, such as those of the type described in WO 2010 / 118543, so that they can be manufactured more easily when using plastics with low glass transition temperatures, particularly biodegradable and / or bio-based plastics, and that the capsules can be reliably sealed.

[0010] According to one aspect of the present invention, a method for manufacturing capsules includes the following steps:

[0011] - Provides a plastic matrix having a base region, circumferential sidewalls, and a circumferential matrix flange adjacent to the circumferential sidewalls;

[0012] - Provide a plastic cap for sealing the capsule, i.e., a plastic cap for forming a closed capsule together with the matrix;

[0013] - Fill the matrix with extracted material;

[0014] - Place the cap on the base so that the fastening part of the cap contacts the base flange;

[0015] -Use ultrasonic welding to fasten the cover flange to the base flange;

[0016] - In this process, when the cover flange is attached, the inner surface of the fastening part contacts the flange surface area of ​​the base flange, and an ultrasonic welding electrode with mechanical vibration and an energy guide is pressed against the outer surface of the fastening part or the outer surface of the flange, so that the plastic material of the cover and the plastic material of the base flange begin to liquefy at the outer surface due to the mechanical vibration.

[0017] When the cover flange is tightened, the inner surface of the tightened portion contacts the flange surface area of ​​the base flange. This specifically means that this contact occurs at the point when energy input is applied or begins. For procedures according to the prior art, no area contact occurs at any point in time: at the start of an ultrasonic welding process according to the prior art, there is no area contact, but only edge contact (line contact) defined by the energy director, and at the end, when the components are welded to each other, no area contact occurs either.

[0018] The effect of this procedure is that the melt first forms on the outer surface, at the contact point between the energy guide and the plastic material, thus essentially forming from the back side. That is, liquefaction begins at the outer surface (“back side”); liquefaction occurs first at the outer surface. The material at the outer surface, in particular, becomes liquid at a certain point in time, while the material at the regional contact location remains solid.

[0019] Due to the continuous pressure and mechanical vibration of the ultrasonic welding electrode, the energy director is subsequently pressed into the plastic material. Liquefaction specifically occurs through the material of the fastening portion or the base flange. As a result, a melt forms at the boundary between the base flange and the fastening portion, for example, as the melt permeates from the outside to another inner surface through the material of the cap or flange. This contrasts with the prior art, where the base or cap itself includes the energy director, and thus line contact generally occurs at the beginning between the base and the cap, where the melting of the plastic begins at the energy director and the contact line.

[0020] Welding occurs at the point where the cover contacts the flange surface area at the start of the process, specifically at the location of the contact area, particularly in the area surrounding the line. The position of the line is defined by the energy director of the ultrasonic welding electrode; that is, the line is the line with the minimum distance from the edge formed by the energy director. In contrast to embodiments where the base flange includes a rolled edge or similar, and the sealing membrane is pressed into the rolled edge or similar to seal the capsule, melting of the material of the base flange and the material of the fastening portion occurs particularly along the flat surfaces that are in parallel contact with each other.

[0021] It has been surprisingly found that procedures with significantly lower efficiency in forming the melt from the back side produce optimal results for plastics such as bioplastics, which have become slightly flowable at relatively low temperatures. Conventional procedures using energy directors on such plastics often produce inadequate welds. One possible explanation for this is that the energy director fails at an early point in the welding process as the plastic softens at low temperatures, because the material is too soft to absorb energy sufficiently. Energy directors located closer to the interior may also create weaknesses in the plastic, as the material deforms and melts there.

[0022] Specifically, the energy input can be configured to originate from the cap side, meaning that when the cap flange is tightened, the ultrasonic welding electrode presses against the tightening portion, while the substrate is supported in the tool (anvil). The plastic material of the cap then liquefies first at its outer surface until a melt also forms at the boundary surface of the substrate flange, for example, as the melt penetrates from the outer surface to that point, and the flange material also liquefies due to heat transfer. This arrangement is often advantageous compared to the opposite arrangement (from the substrate side, i.e., from below), especially because the substrate is filled, and it must be ensured that the filling is not disturbed when the ultrasound acts directly on the substrate. Ultrasound acting from below can also cause implementation problems in practice because the dimensions of the ultrasonic welding electrode cannot be easily determined accordingly for stability reasons.

[0023] The energy director on an ultrasonic welding electrode, such as an energy director for a plastic part to be welded, can have the shape of a rib with, for example, a V-shaped profile. This rib can be arranged circumferentially parallel to the path of the flange. Multiple ribs, such as two parallel to each other, are also conceivable. Other shapes of energy directors are also conceivable, for example, in the form of a single, mountain-shaped protrusion, or arranged circumferentially.

[0024] The contacting surfaces of the base flange and the fastening portion of the cap can be parallel to each other, thus forming a regional contact. The surface portions are particularly free of energy guides or other protrusions or grooves.

[0025] In one embodiment, the outer portion of the common flange formed by the flange of the substrate and the fastening portion welded thereto is removed after welding, for example by means of stamping. In one specific embodiment, this is done because the area on which the energy director acts during welding—i.e., the quasi-core region of the weld—is also removed. In other words, the removal occurs radially inward of the energy director location, closer to the area defined by the circumferential sidewalls.

[0026] The plastic material of the lid can be the same as that of the base plastic. However, the lid can also be made of plastic with a different composition but capable of being welded to the base plastic.

[0027] The plastic material of the lid and / or the plastic material of the cup may be, in particular, bioplastic. The material may be, in particular, a biodegradable plastic. Alternatively or additionally, the plastic material may include, at least in part, bio-based plastic.

[0028] According to the second aspect, a dispensing capsule filled with an extract for manufacturing a reconstituted product is provided, the dispensing capsule comprising:

[0029] - A substrate made of biodegradable plastic, having a base region and circumferential sidewalls;

[0030] - Extract materials or extract fillers, especially ground coffee bean fillers; and

[0031] - A cap made of biodegradable plastic and attached to a substrate, which is also made of the same biodegradable plastic;

[0032] -The cover is welded to the substrate, particularly along the circumferential flange.

[0033] The second aspect is based on the understanding that, contrary to previous views, capsules with lids can also be made using bioplastics and are particularly sealing, wherein the lid is not merely a sealing membrane but a three-dimensional rigid body. In particular, it can be fastened using the method according to the first aspect.

[0034] According to the second aspect, such a capsule can be implemented and manufactured as described above with respect to the first aspect.

[0035] The capsule—for all embodiments, including those of the first aspect—can be specifically implemented such that the substrate and the cap together completely encapsulate the extracted material without any openings, such as those covered by a membrane. The capsule can be hermetically sealed in an oxygen-impermeable manner, for example by including a suitable diffusion barrier. The capsule can particularly have a rectangular cross-section of the shape described herein. Specifically, as described herein, the cap can be implemented as a three-dimensional object, unlike a simple membrane or plate, and can be formed, for example, an outward-facing dome.

[0036] The matrix and / or cap—and this applies to all aspects as well, generally as follows—can be manufactured by injection molding or thermoforming. In embodiments, the material can be a commercially available bioplastic, such as BASF's Ecovio, a biodegradable polyester (polybutylene adipate terephthalate) and polylactide composite.

[0037] In addition to bioplastics, the matrix and cap may specifically include a diffusion barrier layer, thereby preventing the capsule from being permeable to fragrance even without an outer packaging. An example of a diffusion barrier layer is PVOH (polyvinyl alcohol).

[0038] In implementations, the matrix and / or cap can exist, for example, as a multilayer system using bioplastics (e.g., Ecovio) / PVOH / bioplastics, where the PVOH forms a diffusion barrier layer. Particularly for deep-drawn layer systems, a so-called connecting layer, i.e., an adhesive layer, can also be present between the PVOH layer and the bioplastic, such that the structure can then be bioplastic / connecting / PVOH / connecting / bioplastic. Biodegradable connecting layers, such as those in the form of natural waxes, are known and commercially available.

[0039] In one embodiment, the cover is characterized in that, during welding, the cover forms an outwardly dome radially from the circumferential cover flange forming the fastening portion, wherein the dimensions of the circumferential cover flange match those of the base flange. Therefore, the cover according to this embodiment differs from planar cover elements such as membranes or plate-like elements.

[0040] Generally speaking, the cover can be different from a simple membrane and can be three-dimensional, especially a rigid body.

[0041] In this embodiment, the shape of the cap can include, from the outside in, a cap flange, a curved transition region, and a central flat region forming the actual top cap surface. Since the transition region results in a dome, this flat region is offset outward from the plane of the cap flange. For example, the transition region can be S-shaped, or it can bend continuously from the outer portion at an angle to the flange plane to the central flat region. Therefore, its size is chosen, for example, such that the central flat region is optically dominant, for example, because the size of said region is the same as or only slightly smaller than the size of the base region (e.g., a maximum of 10% smaller). For embodiments of capsules that are generally cuboid or cubic in shape, it can be particularly provided that said flat region occupies more than 60% of the diameter and therefore at least 40% of the area.

[0042] The cover flange typically forms a circumferential region facing the cover side and extending from the outer edge of the flange to the starting point of the dome. In an embodiment, the starting point of the dome may be offset inward relative to the sidewall portion adjacent to the flange. This offset may be, for example, a minimum of 0.2 mm.

[0043] The substrate and / or cap can be manufactured, for example, by injection molding or deep drawing methods.

[0044] In the embodiments, the substrate has a substantially rectangular, for example, square cross-section in the flange region. The capsule formed by the substrate and the cap can be approximately cubic in shape, except for the flange retained after manufacturing. The flange itself—for example, its outer edge—can also be substantially rectangular, particularly square. "Substantially rectangular" and "substantially square" do not specifically exclude rounded corners; "approximately cubic in shape" does not exclude rounded edges and corners. The cubic shape also does not exclude, for example, a maximum inclination of 3°, for example, a maximum of 2° or a maximum of 1.5°, relative to the axis (perpendicular to the floor and / or cap region) caused by the manufacturing method of the deep-drawn substrate.

[0045] However, in alternative solutions, the matrix may also have a cup shape of a known type with conical or possibly rotatable cylindrical circumferential sidewalls.

[0046] The wall thickness in the base region is particularly 0.2 mm to 0.4 mm, for example 0.25 mm to 0.35 mm. The same applies to the wall thickness of the cap. In one embodiment, the wall thickness of the cap approximately corresponds to the wall thickness of the base.

[0047] Capsules manufactured according to the method of the first aspect and containing extractive materials include:

[0048] - A matrix made of plastic, especially bioplastic, having a base region and circumferential sidewalls;

[0049] - Extract materials or extract fillers, especially ground coffee bean fillers; and

[0050] - A cap attached to the substrate, which is made of plastic, especially bioplastics;

[0051] -The cover is attached to the substrate by a circumferential flange.

[0052] - And the capsules are manufactured using the method of the type described above.

[0053] The base flange and / or cap flange can be provided in oversized sizes. The excess area is then removed, for example by means of ultrasonic welding or by stamping, after welding or simultaneously with welding.

[0054] Embodiments of the invention are described below using the accompanying drawings. The same reference numerals in the drawings denote the same or similar elements. The drawings are not drawn to scale, and corresponding elements are shown partially at different sizes from one figure to another. What is shown is:

[0055] - Figure 1 capsule;

[0056] - Figure 2 Used to manufacture according to Figure 1 The matrix of the capsule;

[0057] - Figure 3 A cover based on the prior art is shown in cross section;

[0058] - Figure 4 Another cover according to the prior art is also shown in cross-section;

[0059] - Figure 5 The device, shown only in detail, has a base, a cover, an anvil, and an ultrasonic welding electrode;

[0060] - Figure 6 According to the ultrasonic welding process Figure 5 The device; and

[0061] - Figure 7 The substrate and the cap welded to it are shown in detail only after the ultrasonic welding process and before the outer part of the capsule flange is removed.

[0062] according to Figure 1 The capsule 1 is essentially a cube with rounded edges. However, from a purely mathematical point of view, this extension increases slightly towards the top side, giving the capsule a truncated pyramidal shape. The angle of inclination of the side surfaces in the figure relative to the vertical plane of the base surface 5—that is, the plane perpendicular to the base surface that passes through the edge between the base surface and the corresponding side surfaces—is very small, preferably no greater than 2° or only about 1°. The height of the capsule above the base surface also approximately corresponds to the length of the edge of the base surface.

[0063] The capsule includes a base (or cup) 2 and a cap 3 attached thereto along a circumferential flange 4. The base forms a capsule base 5 and circumferential sidewalls 6, which are closed at their outer ends relative to the axial direction (axis 10) by the flange 4 at the top of the figure. The cap is arched outward because the cap surface 9, which is substantially parallel to the capsule base 5, is offset outward compared to the circumferential flange 4.

[0064] Figure 2 The substrate 2 (cup) is shown before filling and sealing. The extension of the substrate flange 41 is greater than the extension of the flange 4 of the finished capsule.

[0065] Figure 1 Capsules of the type shown and Figure 2 The type of substrate 2 shown is also known from the prior art, for example from WO2015 / 096990.

[0066] To manufacture the capsule, the substrate 2 is first filled with the extracted material, and then the cap 3 is positioned. Ultrasonic welding is then performed. When using conventional capsule materials, the cap 3 or substrate 2 is provided with an energy guide in the area of ​​the circumferential flange, for example, an energy guide in the shape of a circumferential rib.

[0067] Figure 3 and 4 One embodiment of cover 3 according to the prior art is shown respectively. Figure 3 The cover 3 is manufactured by deep drawing. The energy guide 23 formed in the region of the cover flange 34 has the shape of a circumferential rib with a cross-section that is approximately V-shaped. Accordingly, a circumferential groove 11 is formed on the back side (i.e., on the outer surface). Figure 4 The cap 3, which is manufactured by injection molding rather than deep drawing, is shown and has an energy guide 23.

[0068] Obviously, when using capsule and cap materials that have softened at relatively low temperatures, the use of materials according to... Figure 3 When using a cap of type 4, welding does not always produce good results reliably.

[0069] Figure 5-7 The method according to the present invention is illustrated using examples. For example... Figure 2 As shown, the substrate 2, made of biodegradable plastic, also includes a circumferential substrate flange 41 that is substantially flat on its top side (flange surface 43). At the transition between the circumferential sidewall 6 and the substrate flange 41, the substrate achieves an optional radially inward thickening 42 to function in a reinforcing manner.

[0070] The cap 3, like the substrate, is rigid and made of the same biodegradable plastic, and includes the same flat inner surface 33 that contacts the flange surface 43 region for attachment, while the substrate flange 41 is supported by an anvil 70. For welding, an ultrasonic welding electrode 50 is pressed against the outer surface 34 of the cap flange and ultrasonic waves are applied. The ultrasonic welding electrode 50 includes an energy director 52. The energy director is achieved by means of a protrusion projecting above the distal effective surface 51, i.e., as a circumferential rib having an approximately V-shaped cross-section and forming an edge downwards due to the shape of the cross-section.

[0071] like Figure 6 As shown, the energy input to the ultrasonic welding electrode 50 causes the material of the cap 3 to liquefy first along the contact with the energy guide 52, allowing the energy guide to penetrate into the material. Due to the continuous application of energy, a melt 61 forms and expands from the location of the energy guide, penetrating from the rear side to the front side of the cap flange material into the base flange material. Alternatively, energy absorption may also occur at the boundary between the cap flange and the base flange. Compared to the prior art, the resulting weld 62 covers a relatively wide area (see...). Figure 7 After the ultrasonic welding electrode is removed, notch 66 can remain in the position of the energy director.

[0072] After welding, the radially outward protrusion of the flange can be removed, for example by stamping, optionally by means of ultrasonic support, ultrasonic cutting, etc. Alternatively, this can occur at a point radially inward of the location where the energy director acts during ultrasonic welding. Figure 7 In the diagram, line 71 indicates the location where the cut occurs. This location is radially inward of the energy director's position (i.e., Figure 7 (See the right side in the details), the energy guide has been marked with a notch in the form of 66. The advantage of this solution is that it produces a more visually appealing flange. The resulting shape at the energy guide's point of action cannot always be precisely replicated. The removal of the portion results in this not always precisely repeatable shape being part of the capsule, and in some cases, it can cause problems when interacting with the mixing chamber during processing and mixing.

Claims

1. A method for manufacturing a portioned capsule (1) filled with extraction material for manufacturing an infusion product, comprising the steps of: - providing a base (2) made of plastic having a base area (5), a circumferential side wall (6) and a circumferential base flange (41) adjacent to the circumferential side wall; - providing a lid (3) made of plastic; - filling the base (2) with extraction material; - placing the lid (3) on the base (2) such that a fastening portion of the lid contacts the base flange (41); and - fastening the lid flange to the base flange by means of ultrasonic welding, characterized in that - when attaching the lid flange, an inner surface (33) of the fastening portion is in contact with a flange surface (43) area of the base flange and an ultrasonic welding electrode (50) with an energy director (52) is pressed against an outer surface (34) of the fastening portion or an outer surface of the base flange such that the plastic material of the lid and the plastic material of the base flange start to liquefy at the outer surface due to the mechanical vibrations and the liquefaction proceeds from the outer surface to the inner surface of the fastening portion or the base flange and then forms a melt at the border between the base flange and the fastening portion.

2. The method of claim 1, wherein, When fastening the lid flange, the ultrasonic welding electrode (50) is pressed against the fastening portion while the base (2) is supported by a tool (70).

3. The method of claim 1 or 2, wherein, The inner surface (33) of the fastening portion and the flange surface (43) of the base flange are flat and parallel to each other.

4. The method of claim 1 or 2, wherein, The energy director (52) has the shape of a circumferential rib.

5. The method of claim 1 or 2, wherein, An outer portion of the common flange (4) resulting from the base flange (41) and the fastening portion welded thereto is cut off after welding.

6. The method of claim 5, wherein, The outer portion is cut off such that the area where the energy director acts during welding is also cut off.

7. The method of claim 1 or 2, wherein, The lid (3) and the base (2) are made of the same plastic.

8. The method of claim 1 or 2, wherein, The lid (3) and / or the base (2) are made of biodegradable plastic.

9. The method of claim 8, wherein, The lid and the base comprise a diffusion barrier.

10. The method of claim 9, wherein, The diffusion barrier is made of PVOH.

11. The method of claim 1 or 2, wherein, The lid (3) is rigid.

12. The method of claim 11, wherein, The lid (3) forms an outward dome radially inwardly from a circumferential lid flange forming the fastening portion during welding.

13. The method of claim 1 or 2, wherein, The base has a substantially rectangular cross section in the area of the base flange.

14. A portioned capsule (1) made of plastic and filled with extraction material for manufacturing an infusion product, comprising: - a base (2) made of plastic having a base area (5) and a circumferential side wall (6); - an extraction material or extract filling; and - a lid (3) made of plastic and attached to the base; - wherein the lid is attached to the base along a circumferential flange, - and wherein the portioned capsule is manufactured by a method according to any of the preceding claims.

15. The portioned capsule (1) made of plastic and filled with extraction material for manufacturing an infusion product according to claim 14, wherein the plastic is a bioplastic. ​ 16. A portion capsule (1) made of plastic and filled with an extraction material for the production of an infusion product according to claim 14, wherein the extraction material or extract filling is a ground coffee bean filling.

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