Method for producing a fibre-based product

Abstract

Disclosed is a method for producing a fibre-based product, in particular a capsule (100), comprising a barrier layer (30), the method having the steps of: - providing a nonwoven fabric (20) made of fibres, in particular natural fibres, - providing the barrier layer (30) in the form of a film, - laying the nonwoven fabric (20) and the barrier layer (30) one on top of the other to form a semifinished product (40). The semifinished product (40) is introduced into a mould (50) and is pressed in the mould into the final contour shape of the product, such that the barrier layer forms an integral part of the product.

Description

[0001] Process for producing a fiber-based product

[0002] The present invention relates to a method for producing a fiber-based product comprising a barrier layer according to the preamble of the independent claims.

[0003] Various fiber-based products with barrier layers are known from the state of the art, along with different manufacturing processes. Barrier layers are typically required to protect sensitive contents, such as coffee grounds or other foodstuffs, from gases and liquids such as oxygen, steam, or water.

[0004] EP 3 513 000 B1 discloses a method for producing coffee capsules, in which preforms are produced from a suspension of water and fibers in a continuous process. These are then pressed in a mold and dried. Provision may be made for the introduction of a barrier layer in a further step. This method requires a multitude of different pressing operations and the supply of different material streams, such as the barrier layer, during the production process, which makes this process complex, time-consuming, and prone to errors.

[0005] WO 2023 / 180288 A1 discloses a process in which a fiber-based product is manufactured from a semi-finished product. In this process, the semi-finished products are produced intermittently, and each semi-finished product is adjusted to specific parameters, such as humidity.

[0006] EP 3 030 503 B2 discloses a substantially compostable capsule having an oxygen-permeable layer, wherein this layer is incorporated into the capsule in a co-injection molding process. To improve the properties of the capsule, it can be coated with an additional outer oxygen-permeable and vapor-impermeable coating. This process is also complicated and time-consuming. In co-

[0007] During the injection molding process, numerous parameters must be monitored. An additional coating requires additional processing or manufacturing equipment.

[0008] It is therefore an object of the invention to remedy at least one or more disadvantages of the prior art. In particular, a method is to be provided that is simple, preferably has low energy requirements, and, in particular, is resource-efficient.

[0009] This object is achieved by the method described in independent claim 1. Further embodiments emerge from the dependent claims.

[0010] A method according to the invention for producing a fiber-based product, in particular a capsule, comprising a barrier layer, comprises the steps:

[0011] - Providing a nonwoven fabric made of fibres, in particular natural fibres,

[0012] - providing the barrier layer in the form of a film, in particular a recyclable film,

[0013] - Overlaying the nonwoven fabric and the barrier layer to provide a semi-finished product.

[0014] The semi-finished product is then placed in a mold and pressed into the final contour of the product so that the barrier layer forms an integral part of the product.

[0015] The fleece provided is dry, i.e., has a moisture content of less than 20% by mass, in particular between 4% and 16%, preferably between 6% and 11%. Preferably, the fleece is produced using a dry process, and therefore not from pulp with washed-up fibers, but from dry fibers.

[0016] A film is a thin, continuous layer, particularly in the form of a foil. The thickness of this film does not exceed 1 mm, particularly 0.5 mm, preferably 0.2 mm. Preferably, the film thickness is selected such that its mass fraction in the finished product does not exceed 15%, preferably 10%.

[0017] A mold for a product comprises a negative of the product's outer contour. Typically, for example, in the case of containers open on one side, such as cups, bowls, or coffee capsules, the mold is made up of two parts. The first half of the mold corresponds to the outer contour of the container, and the second half to the inner contour. In this case, after the two mold halves are joined, a wall thickness of the container is provided. In other words, a container wall can be pressed between the two mold halves.

[0018] By preparing a semi-finished product—that is, all the layers required for a specific purpose—the final product can be produced in a single pressing process. In the case of coffee capsules, for example, this final product is the container that is not yet sealed with a lid.

[0019] A single pressing process can comprise several individual pressings, for example, a first pressing to produce a prefabricated product and a second pressing to finalize the final contour. No additional products or layers are added between the individual pressings.

[0020] Since the fleece, in particular, is dry, little or no consideration needs to be given to possible parameters prior to product production, such as high residual moisture levels in the fleece and the associated special handling of a preformed blank, such as complex drying. In some cases, it may simply be appropriate to spray the fleece with water before the pressing process to make it more pliable, thus improving its formability.

[0021] The starting materials are therefore in solid form and are bonded and formed without the addition of liquids such as water or solvents or without separate melting, simply by applying pressure and temperature and in a short cycle time.

[0022] The products manufactured using these processes, such as a container, particularly in the form of a coffee capsule, exhibit high barrier properties against the aforementioned substances. They are easy to manufacture and do not require complex coating processes to achieve barrier properties.

[0023] Preferably, the film is a biodegradable film; more preferably, the biodegradable film is a polymer, especially a bio-based polymer. Bio-based polymers are often also biodegradable. This makes it possible to add the container, since it is made from a fiber material, together with the biodegradable film, for example, to home composting. The fibers for the nonwoven fabric are, in particular, biodegradable fibers, especially natural fibers such as hemp fibers, cellulose fibers, or flax fibers, or a mixture thereof.

[0024] The biodegradable film is made of one or more materials from the group of materials comprising cellulose acetate and its derivatives, cellulose with a lignin content of less than 5%, lignin, starch and its derivatives, in particular thermoplastic starch, alginates, algae-based polymers, protein-based polymers, polybutylene adipate terephthalate (PBAT), polylactides (PLA), polyvinyl alcohol (PVOH), polyhydroxyalkanoates (PHA) and their copolymers, polyhydroxybutyrates (PHB) and their copolymers, polyhydroxybutyrate hexanoate (PHBH)), poly (3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV), polybutylene succinate (PBS) and its copolymers, poly (butylene succinate-co-butylene adipate) (PBSA), microfibrillated Cellulose (MFC) and modified microfibrillated cellulose (MFC mod), nanofibrillated cellulose (NFC) and modified nanofibrillated cellulose (NFC mod), montmorillonite-modified bacterial cellulose composites (CNC-MMT-Soy),Nanofibrillated cellulose / cellulose nanocrystals with montmorillonite-modified bacterial cellulose composites (NFC / CNC-MMT-Soy), as well as whey protein-based polymers, wheat gluten-based polymers, casein, soy protein-based polymers, pectin, and chitosan. These are all biobased materials and / or biodegradable, or can be biodegraded using, for example, specific pH values ​​or temperatures or modification.

[0025] Preferably, the nonwoven fabric is prepared using an air-laid process before being prepared. This allows the nonwoven fabric to be prepared ad hoc and tailored to specific product parameters, for example. Time-consuming transport of the finished nonwoven fabric can be eliminated. Furthermore, unwanted settling of the nonwoven fabric before pressing can be avoided, for example, because the unprocessed nonwoven fabric has a short service life.

[0026] Alternatively, however, it is also possible for the nonwoven to be provided in roll form. In such a configuration, it is possible for a corresponding nonwoven to be prefabricated and, for example, for fibrous or less dense edge areas that cannot be used in the manufacturing process to have already been removed, thus allowing the desired quantity and quality to be provided for immediate production start. The barrier layer can, in particular, be provided as a film. This makes it possible to also provide it in roll form, thus enabling the semi-finished product to be produced essentially continuously.

[0027] This enables continuous processing of the semi-finished product following its provision, so that a single cycle or intermittent manufacturing process becomes superfluous.

[0028] It may also be provided that the semi-finished product, or the steps for producing the semi-finished product, are carried out in advance and that the semi-finished product is made available as rolled goods before the pressing process.

[0029] Depending on the container to be formed, it may be necessary to preform the semi-finished product after it has been introduced into the mold using a ram in the cavity of the mold. Particularly for containers that have a great depth relative to their diameter, this type of preforming can help prevent cracks or stresses in the finished container.

[0030] Alternatively or additionally, it can be provided that the semi-finished product is pre-formed by means of a negative pressure after being introduced into the mold and / or is held within the mold.

[0031] On the one hand, this is a particularly gentle form of preforming; on the other hand, the preformed state can be easily maintained by applying a vacuum, so that the desired parameters are met during the final pressing process. In other words, it ensures that the fleece is at a specific, required location in the mold during a subsequent pressing process.

[0032] After the pressing step, any excess edge on the product can be removed by punching. This punching process allows the product to be finished as desired, so that, for example, a lid can be attached to the product itself without any further processing steps.

[0033] The punched-out scraps are preferably removed from the process, and in particular, they are separated into their components and recycled. This reduces both production costs and material consumption.

[0034] After the pressing step, the product is preferably removed from the mold, in particular by means of a mechanical gripper or a vacuum gripper. In particular, removal with a gripper allows the thus formed product to be transferred to a further process step, for example, to a filling system.

[0035] The products may also be subjected to quality control, particularly before they are sent to a further process step.

[0036] This ensures that only products that meet specific quality requirements are processed.

[0037] It can be provided that further layers in the form of nonwovens and / or barrier layers are made available so that a multi-layer semi-finished product can be provided. In particular, it can be provided that a nonwoven is provided first, a first barrier layer is placed on this nonwoven, and a second nonwoven is placed on the first barrier layer. Accordingly, a semi-finished product is obtained which is designed as a sandwich construction. In other words, the barrier layer is arranged in the form of a film, in particular a biodegradable film, between two nonwovens made of fibers. This arrangement ensures that the film is protected on both sides by a nonwoven layer and is therefore also protected, for example, against mechanical damage.

[0038] The fleece layer in the semi-finished product preferably has a thickness of 5 mm to 15 mm and is pressed to a final thickness of 0. 5 mm to 5 mm, in particular 1 mm to 2 mm.

[0039] In particular, it can also be provided for the functions of the individual layers in a multi-layer structure to be separated. For example, depending on the product requirements, several barrier layers with different properties can be combined in different ways, for example an oxygen barrier layer to optimize oxygen permeation and a water vapor barrier layer to optimize water vapor permeability. It is not absolutely necessary to provide a fleece between the individual barrier layers. It is also possible, for example, to place two barrier layers with different properties on top of each other. Typically, however, a fleece would also be arranged between the barrier layers and, for example, a water vapor barrier would be arranged as the innermost layer, in direct contact with the contents.

[0040] In particular, it can be provided that the semi-finished product is fed continuously, but is punched out according to a rough contour before being introduced into the mold, so that it can be pressed more easily because its deformation is not restricted by the remaining semi-finished product hanging on it.

[0041] The invention is explained below with reference to schematic figures. It shows:

[0042] Figure 1 : A semi-finished product;

[0043] Figure 2: the semi-finished product from Figure 1 in the mold before the pressing process; Figure 3: the pressing process;

[0044] Figure 4 : the completion of the pressing process .

[0045] Figure 1 shows a semi-finished product 40 and its manufacturing process. As can be seen, the semi-finished product 40 is in this case designed in three layers. A first layer made of a nonwoven fabric 20 made of fibers is provided. This nonwoven fabric 20 is provided as a roll, although this is not shown in full in Figure 1. Also provided is a second layer, namely the barrier layer 30 in the form of a biodegradable film. The barrier layer 30 is also provided as a roll. In addition, a third layer is provided, namely a further nonwoven fabric 20', likewise as a roll. These three layers are placed on top of one another, so that in the present example the barrier layer 30 is arranged between the first nonwoven fabric 20 and the second nonwoven fabric 20'. This creates a semi-finished product 40, in this case comprising three layers, a first nonwoven fabric 20, a barrier layer 30 and a second nonwoven fabric 20'.

[0046] This semi-finished product 40 is then introduced into a mold 50. This step is shown in Figure 2. The mold 50 in the present case comprises a first mold half 50A and a second mold half 50B. The first mold half 50A corresponds to the inner contour of a later container 100 (see Figure 4) and the second mold half 50B corresponds to a corresponding outer contour of the container 100. The semi-finished product 40 is introduced between these two mold halves 50A and 50B and, if necessary, pre-formed with a ram.

[0047] Figure 3 shows the actual pressing process. The mold 50 is closed by inserting the first mold half 50A into the second mold half 50B. The semi-finished product 40 deforms according to the contour located between the two mold halves 50A and 50B and is pressed accordingly to the final wall thickness of the end product, i.e., the container 100. Through this pressing process, the barrier layer 30 becomes an integral part of the product, in this case the container 100, and can no longer be separated or detached from it.

[0048] In this case, it can be provided that the semi-finished product 40 is subjected to increased heat and / or increased pressure during the pressing process, if necessary over a certain period of time, so that the pressed container 100 retains its shape.

[0049] Figure 4 shows the process after the container 100 has been completely pressed. After the pressing process, the mold 50 is opened, i.e., the first mold half 50A is removed from the second mold half 50B, and the finished container 100 is demolded. If necessary, an excess edge on the container 100 can be punched out before demolding. This finished container 100 can then be transferred to the next production process, for example, a filling system, by means of a gripper.

Claims

Patent claims 1. A method for producing a fiber-based product, in particular a capsule (100) comprising a barrier layer (30), comprising the steps: - Providing a nonwoven fabric (20) made of fibers, in particular natural fibers, - providing the barrier layer (30) in the form of a film, in particular a recyclable film, - superimposing the nonwoven fabric (20) and the barrier layer (30) to provide a semi-finished product (40), characterized in that the semi-finished product (40) is introduced into a mold (50) and is pressed therein into the final contour of the product, so that the barrier layer forms an integral part of the product.

2. The method according to claim 1, wherein the film is a biodegradable film, in particular the biodegradable film is a polymer, in particular a bio-based polymer.

3. The method according to claim 2, wherein the biodegradable film is made of one or more materials selected from the group of materials comprising: cellulose acetate and its derivatives, cellulose with a lignin content of less than 5%, lignin, starch and its derivatives, in particular thermoplastic starch, alginates, algae-based polymers, protein-based polymers, polybutylene adipate terephthalate (PBAT), polylactides (PLA), polyvinyl alcohol (PVOH), polyhydroxyalkanoates (PHA) and their copolymers, polyhydroxybutyrates (PHB) and their copolymers, polyhydroxybutyrate hexanoate (PHBH), poly (3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV), polybutylene succinate (PBS) and its copolymers, poly (butylene succinate-co-butylene adipate ) (PBSA), microfibrillated cellulose (MFC) and modified microfibrillated cellulose (MFC mod), nanofibrillated cellulose (NFC) as well as modified nanofibrillated cellulose (NFC mod), montmorillonite modified bacterial cellulose composites (CNC-MMT-Soy), nanofibrillated cellulose / cellulose nanocrystals montmorillonite modified bacterial cellulose composites (NFC / CNC-MMT-Soy), as well as whey protein based polymers, wheat gluten based polymers, casein, soy protein based polymers, pectin, chitosan.

4. Method according to one of claims 1 to 3, characterized in that the nonwoven fabric (20) is provided in an air-laid process before being provided.

5. Method according to one of claims 1 to 4, characterized in that the nonwoven fabric (20) is provided as a roll.

6. Method according to one of claims 1 to 5, characterized in that the barrier layer (30) is provided as a film.

7. The method according to claim 6, characterized in that the film is provided as a roll.

8. Method according to one of claims 1 to 7, characterized in that the semi-finished product (40) is pre-formed into a cavity of the mold (50) by means of a ram after being introduced into the mold (50).

9. Method according to one of claims 1 to 8, characterized in that the semi-finished product (40) is pre-formed and / or held by means of a negative pressure after being introduced into the mold (50).

10. Method according to one of claims 1 to 9, characterized in that after the step of pressing by means of a During the punching process, an excess edge is removed from the product.

11. The method according to claim 10, characterized in that the punched-out residues are removed from the process.

12. Method according to one of claims 1 to 11, characterized in that after the pressing step, the product is removed from the mold, in particular by means of a mechanical gripper or a vacuum gripper.

13. Method according to one of claims 1 to 12, characterized in that the products are subjected to a quality control.

14. Method according to one of claims 1 to 13, characterized in that further layers in the form of nonwovens (20, 20') and / or barrier layers (30) are provided, so that a multi-layer semi-finished product (40) can be provided.

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