Method for film production with laser engraving as a predetermined breaking point

Abstract

A cost-effective method for producing a film (1) as part of a packaging container (K) is proposed, in order to at least partially enclose the interior (6) of the packaging container (K), wherein the film (1) is designed to tear at a predetermined breaking point under mechanical pressure in order to provide access to the interior (6), with: - Providing the film (1) as a monofilm or composite film with at least one layer (2, 3) in which at least the outer and / or inner layer (2) with respect to the interior (6) is made of plastic, - Creating a predetermined breaking point in the form of a laser engraving (4) by removing part of the film (1) using a laser, wherein the removal is carried out as a local reduction of the film thickness by the laser and thus the predetermined breaking point is formed as a laser engraving (4).

Description

[0001] The invention relates to a method for producing a film according to the preamble of claim 1 and a packaging container according to the preamble of claim 10. Furthermore, a film according to the preamble of claims 11 and 12 and a packaging container according to the preamble of claim 20 are proposed.

[0002] Various blister-type packaging containers are known from the prior art, such as tablet packs as push-through packs and coffee capsules for preparing hot coffee beverages. Traditionally, such tablet packs have had an aluminum foil lidding film on a deep-drawn part. Modern tablet packs are intended to be more sustainable. For this reason, aluminum is now being dispensed with and exclusively plastic is used. While some coffee capsules are also traditionally made of aluminum, attempts are now being made to use recycled material for more environmentally friendly products, such as plastic, as described in EP 4 173 978 A1, and / or a compostable material, as proposed in EP 3 847 014 A1, for example. This is because the capsule is a typical disposable item and is thrown away after one use.However, it has been found that manufacturing using such an alternative to aluminum is generally more costly.

[0003] The object of the invention is to propose a film or a manufacturing method for a corresponding film which can eliminate these disadvantages and in particular allows more cost-effective production without loss of quality.

[0004] The object is achieved by the characterising features of claim 1, starting from a film or a manufacturing process of the type mentioned at the outset.

[0005] Advantageous embodiments and further developments of the invention are possible by the measures mentioned in the dependent claims.

[0006] In a packaging container according to the invention, such as a coffee capsule, coffee powder or a powder for preparing a beverage is stored. The coffee capsule has an interior for this purpose. Preparation itself is generally carried out by rinsing the interior, so that hot water comes into contact with the powder. To gain access to the interior, the capsule must be opened or broken open. For this purpose, a film is provided which at least partially delimits the interior of the capsule. This film can generally be used as the lid film for the capsule. A film can be broken through more easily than, for example, a thicker plastic tub, such as that found in blister packs.

[0007] A tablet package according to the invention can, for example, be a push-through pack. Pressure is applied to the deep-drawn part with the fingers. This force is transferred to the tablet and, in turn, to the foil, which is intended to tear open, allowing the tablet to escape from the interior to the outside.

[0008] Originally, aluminum foil, which is commonly used for packaging and storing food, was used primarily. However, aluminum production is not particularly environmentally friendly.

[0009] In the case of a coffee capsule, the film can traditionally be broken open mechanically using a spike that pierces the film. However, particularly with plastic films or plastic capsules, there is a risk that film particles or film residue will break off and get into the drink, which should be avoided for various reasons (health, quality, hygiene). However, plastic films usually have poorer breaking properties than aluminum foil. Conventional push-through packs for tablets made of plastic are generally much heavier and require more force to open than those with an aluminum lid film. If an additional barrier layer is added to a plastic film, comparable breaking properties to those of aluminum foil are often not available, which means that its suitability for packaging production is questionable. Mechanical breaking can be difficult with plastic films, e.g.For example, mono- or recycled foils can also be pressed through the high pressure of the steam acting on the capsule. However, even here, there is a risk of foil particles or foil residues becoming detached. The same risk exists with conventional tablet push-through packs.

[0010] As an alternative to improving the breaking properties of a plastic film, it can be scored with very fine marks using an embossing roller. However, during the development of the invention, it was recognized that this method is associated with high costs. It is complex and requires high tooling costs. The embossing roller not only has to be manufactured but also wears out quickly as a tool. Furthermore, temperature influences lead to expansion problems. Manufacturing methods are inflexible, and adjustments may require the embossing tool to be remade each time. Requirements for long-term quality cannot be met.

[0011] The invention is therefore characterized by the creation of a predetermined breaking point that breaks under mechanical pressure at a defined location on the film. This predetermined breaking point is created as a laser engraving, making a mechanical embossing tool, for example, obsolete. Mechanical tool wear is thus essentially completely avoided.

[0012] However, laser engraving according to the invention also offers further advantages: - There's no need to manufacture a new, complex and expensive tool if the capsule product to be manufactured changes, for example, if the shape / contour of the predetermined breaking point or the depth or track width of the predetermined breaking point is altered. Instead, it's usually sufficient to reprogram the laser control system. - Even if the capsule material is changed, e.g. a different plastic, no other tool is usually necessary, just a change in the control process. - The changeover time is also much shorter because, for example, only the control system needs to be reprogrammed, which is usually much faster than manufacturing a stamping tool. This allows for higher production numbers.

[0013] To enable the film to be broken open cleanly and with a defined geometry, the laser engraving can be linear. In principle, it is also conceivable to provide weakenings in the material using point-shaped recesses. Particularly when the capsule is opened by mechanical pressure, in particular by steam, in the area of ​​the predetermined breaking point - for example when the capsule is rinsed with hot water inside to prepare a drink - it is important that no film residue or film particles get into the water and thus later into the drink. It is therefore advantageous to provide a predetermined breaking point that runs over a longer distance, because otherwise the film material would have to tear open even in places where there is no weakening in terms of thickness, which in turn can lead to individual film components tearing out more easily.The more defined the predetermined breaking point is prepared by laser engraving, the more reproducible and qualitatively better the result of the beverage preparation can be.

[0014] Likewise, such particles from the lidding foil should not be found as residues on the tablet.

[0015] To completely detach a surface area, a closed area of ​​the foil can also be delimited by the laser engraving. However, with coffee capsules, the printing process generally doesn't want to cut out a continuous area of ​​the foil, since the capsule, as a packaging container, is intended to be opened but not divided into several parts, which could, for example, impede the water flow.

[0016] In a further development of the invention, the laser engraving takes place as a so-called cold ablation process. Cold ablation, for example, enables engraving without a melted edge, thus preserving the smooth film surface. A thickening at the edge can, for example, lead to the undesirable deposition of tiny dirt particles. It can also cause sealing problems or similar issues and is therefore a rather disruptive artifact. Such cold ablation can be achieved, for example, using a laser emitting in the ultraviolet range, at a wavelength of approximately 355 nm. In contrast, a CO2 laser results in material ablation with a melted edge.

[0017] In an environmentally friendly way, the film and therefore also the packaging container, for example the tablet packaging or the coffee capsule, can be made without aluminum. Instead, a recyclable material can be used. Compostable materials are also conceivable. Plastic, for example, can generally be easily recycled. Some plastics can also be composted. In order to open a film at the predetermined breaking point using the steam pressure generated in the coffee machine or vending machine, it can be advantageous to make the film as thin as possible, for example in the form of a single-layer monofilm. However, the use of composite materials is also conceivable, which enable more defined properties as a composition of different material functionalities. One layer, in particular the outer layer on the surface, can be designed as a plastic layer, which is also provided with the laser engraving. It is also conceivable that at least two or moreall layers are made of plastic.

[0018] One of the layers can, for example, be designed as a barrier layer to protect the food or pharmaceutical product stored inside, for example, an EVOH layer (EVOH: a copolymer of ethylene and vinyl alcohol, produced from the polymerization of ethylene and vinyl acetate). The barrier layer can also be laser-engraved to create a predetermined breaking point. Until now, the required breaking properties of a predetermined breaking point could hardly be achieved with barrier layers using state-of-the-art technology, as only embossing tools were used to weaken the material.

[0019] Depending on the embodiment of the invention, the track depth can, for example, cover a single layer and not completely penetrate it, or it can cover multiple layers. Typically, this laser engraving, viewed across the film, looks like a wedge or a blind hole ending in one of the film layers. The film layer(s) above, unless it is a single film, are then completely penetrated. With composite materials, the laser engraving may need to cover more than one layer to allow the film to be opened.

[0020] Due to its high tensile strength, biaxially oriented PET film (BOPET, where PET stands for polyethylene terephthalate) is also ideal for aroma-tight food packaging. The film thickness can generally range from 15 µm to 50 µm.

[0021] In order to achieve a good compromise between strength and openability of the predetermined breaking point, the removal can be in the depth range of 5 µm to 30 µm, while the track width varies between approximately 15 µm and 50 µm depending on the design.

[0022] An advantageous embodiment of the invention is the capsule in the form of a blister pack. This comprises a plastic molded or deep-drawn part, which defines the interior space due to its shape. It has an opening to which a film can be applied and secured or sealed. The film is generally thinner and weaker than the deep-drawn part, allowing the predetermined breaking point to be integrated into the film. The blister pack can be transported relatively safely.

[0023] Accordingly, a manufacturing method according to the invention is characterized by creating a predetermined breaking point in the form of a laser engraving by ablating a portion of the film using a laser, wherein the ablation takes the form of a local reduction in the film thickness, so that the predetermined breaking point is formed as a laser engraving. The advantages already explained in connection with the coffee capsule can be utilized here. More environmentally friendly, aluminum-free capsules can be produced without mechanical tools and instead with an optical tool, a laser for creating a laser engraving. This can save costs and shorten production times. In addition, material can be saved because new tools do not have to be built due to product changes or wear. Temperature influences and the like play a lesser role. The films or packaging to be produced have lower waste.

[0024] In a further development of the invention, the geometry of the laser engraving is achieved using a mirror deflection system or a scanner. By programming the corresponding control system, which aligns the mirrors, the laser beam can be directed, thus creating a wide variety of geometries.

[0025] Alternatively, it is also conceivable to leave the laser stationary and instead move the film relative to the laser beam using a positioning system in order to obtain the desired geometry.

[0026] Net-like line structures can be created just as easily as parallel lines. The line spacing can also be varied. In areas where lines would otherwise intersect, a point without overlaps can be created by interrupting the laser beam that would otherwise impinge there. The laser can also be temporarily deactivated in these areas. These measures allow the pressure or force required to tear the film at the predetermined breaking point to be adjusted.

[0027] According to the invention, a coffee capsule is also proposed which has undergone a removal of an engraving line or track without a melted edge, so that the engraving can be located in an outer plastic layer.

[0028] In some packaging containers, especially tablet packaging in the form of a push-through pack, the foil can also be arranged so that the laser engraving is located inside, from where the force acts on the foil. Such an arrangement is also conceivable for coffee capsules. Examples of implementation:

[0029] Embodiments of the invention are illustrated in the drawings and are explained in more detail below, giving further details and advantages.

[0030] In detail: Fig. 1: a schematic section through a film according to the invention, Fig. 2: a schematic section through a coffee capsule according to the invention, Fig. 3: a schematic representation of a laser engraving according to the invention, as well as Fig. 4: a schematic representation of a manufacturing process of a coffee capsule according to the invention.

[0031] Fig. Figure 1 shows a schematic section through a film 1, which is composed of two layers 2, 3. Both layers 2, 3 are made of plastic. A laser engraving 4 is incorporated into the film 1, which in turn has a track width B and a depth T. The laser engraving 4 forms the predetermined breaking point in the film 1 and completely penetrates the outer layer 2 (here in Fig. 1: the upper layer 2). The laser engraving 4 also partially covers the lower layer 3. The film 1 is thus locally reduced in thickness in the area of ​​the laser engraving 4. As can be seen from the side of the laser engraving 4, there are no melt edges on either side of the laser engraving 4. The predetermined breaking point or laser engraving 4 is wedge-shaped in this case. Compared to a wider, trough-like shape, this offers the advantage that the area can break more easily under pressure.

[0032] Fig. Figure 2 shows a schematic section through a coffee capsule K in the form of a blister pack. It consists of a pot-shaped deep-drawn part 5 made of a thicker plastic than the film 1 used as a lidding film, with which the deep-drawn part 5 is covered. Inside the deep-drawn part 5, bordered at the top by the covering film 1, is the interior 6 of the coffee capsule K, which is filled with coffee powder. The film 1 is sealed on the edge of the deep-drawn part 5.

[0033] A predetermined breaking point with a Laserbravur 4 is in Fig. 3 can be seen on a foil 1. It is round, with the track 4 being interrupted at one point so that the material does not get into the coffee during the brewing process, ie the lid in the middle of the predetermined breaking point remains connected to the foil 1.

[0034] In Fig. 4 outlines a manufacturing process: - The foil can be provided. - The laser is positioned relative to the film using a scanner. - Then the laser engraving takes place, with the laser still following the desired engraving line using the scanner. - The film can be cleaned or sterilized if necessary, e.g. by gently blowing it off with a gas.

[0035] Meanwhile, a kind of blister can be created. This is done by following these steps: - A molded part is deep drawn. - The deep-drawn part is cleaned, e.g. by blowing. - The molded part is filled with coffee powder. If necessary, this is done under gassing to ensure the coffee powder lasts longer in the capsule K and does not lose its aroma. During filling, the capsule is weighed, or pre-portioned amounts of powder are added.

[0036] Both, deep-drawn part 5 and film 1 form the finished capsule K. Film 1 and deep-drawn part 5 must be connected to each other, here sealed, so that no ambient air gets to the coffee powder stored in the interior 6 and damages it or its aroma.

[0037] All embodiments and developments of the invention have in common that a predetermined breaking point is created in order to tear by mechanical pressure at the predetermined breaking point and to provide access to the interior, wherein at least the outer or inner layer with respect to the interior is made of plastic; they are characterized in that the predetermined breaking point is designed as a laser engraving, in which the film thickness is locally reduced by ablation with a laser. List of reference symbols: 1 slide 2 outer plastic layer 3 more layers 4 Laser engraving 5 Deep-drawn part 6 Interior of the capsule 7 Interruption of engraving B track width K coffee capsule T track depth QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] EP 4 173 978 A1

[0002] EP 3 847 014 A1

[0002]

Claims

[1] Method for producing a film (1) as part of a packaging container (K) in order to at least partially delimit the interior (6) of the packaging container (K), wherein the film (1) is designed to tear at a predetermined breaking point by mechanical pressure in order to thus release access to the interior (6), comprising: • Providing the film (1) as a monofilm or composite film with at least one layer (2, 3), in which at least the outer and / or inner layer (2) with respect to the interior (6) is made of plastic, • Creating a predetermined breaking point in the form of a laser engraving (4) by removing a part of the film (1) using a laser, wherein the removal takes place as a local reduction of the film thickness by the laser and thus the predetermined breaking point is formed as a laser engraving (4). [2] Manufacturing process according to claim 1, characterized bythat a UV laser, preferably in the range of a wavelength of 355 nm, is used as the laser, in particular to carry out cold removal without the formation of a melt edge in the edge area of ​​the laser engraving (4). [3] Manufacturing process according to one of the preceding claims, characterized by that the laser beam of the laser used for ablation and / or production of the laser engraving (4): • is positioned relative to the film via a mirror deflection system, preferably a scanner and / or • remains stationary while the film (1) is moved relative to the laser beam. [4] Manufacturing process according to one of the preceding claims, characterized by that the following material is provided as slide (1): • a film with a thickness of 15 µm to 50 µm and / or • a 2-layer BOPET film. [5] Manufacturing method according to one of the preceding claims, characterized bythat during the ablation a laser engraving (4) with a track width of 15 µm to 50 µm is created. [6] Manufacturing process according to one of the preceding claims, characterized by that during the ablation a laser engraving (4) with a track width of 15 µm to 50 µm is produced and / or that the ablation produces a laser engraving depth of 5 µm to 30 µm. [7] Manufacturing method according to one of the preceding claims, characterized by that the breaking behavior of the predetermined breaking point (4) is adjusted by • a net-like line structure is removed as a laser engraving and / or • at least two parallel lines are laser engraved and / or • the line spacing of the laser engravings (4) is varied during removal. [8] Manufacturing process according to one of the preceding claims, characterized by that in addition to the lines at least one point-like structure is removed. [9] Manufacturing process according to one of the preceding claims, characterized by that intersecting lines without overlapping are produced as laser engraving (4) by interrupting the laser beam in the overlapping area of ​​the lines and / or switching off the laser there. [10] Method for producing a packaging container, in particular a coffee capsule (K) and / or a tablet package and / or a push-through pack and / or a transparent package and / or a blister pack, wherein a plastic molded part (5) forming an interior space (6) is molded and at least partially covered and connected to a film (1) as a rear wall in order to at least partially delimit the interior space (6), characterized by that a method for producing the film (1) according to one of the preceding claims is used. [11] Film (1) or packaging container (K), obtainable according to one of the preceding claims. [12] Film (1) for at least partially delimiting the interior (6) of a packaging container (K), wherein the film (1) is designed as a monofilm or composite film with at least one layer (2, 3) and has a predetermined breaking point in order to tear by mechanical pressure at the predetermined breaking point in order to release access to the interior, wherein the layer or at least one of the outer or inner layers (2) is made of plastic, characterized by that the predetermined breaking point is designed as a laser engraving (4), in which the film thickness is locally reduced by ablation with a laser. [13] Film (1) according to one of the preceding claims, characterized by that the laser engraving (4) is at least partially, in particular completely, linear and / or delimits a closed surface area on the film (1). [14] Film (1) according to one of the preceding claims, characterized bythat the laser engraving (4) is limited without a melting edge and thus without local thickening of the foil (1) at the edge of the track of the laser engraving (4) [15] Film (1) according to one of the preceding claims, characterized by that the film (1) and / or all layers (2, 3): • made of plastic and / or • made of a recyclable material and / or • is / are made of aluminum-free material. [16] Film (1) according to one of the preceding claims, characterized by that at least one barrier layer, in particular an EVOH layer, is provided. [17] Film (1) according to one of the preceding claims, characterized by that the removal of the laser engraving (4) covers at least one, in particular all layers (2, 3) of the film (1). [18] Film (1) according to one of the preceding claims, characterized by that the slide (1): • has a thickness of 15 µm to 50 µm and / or • is designed as a 2-layer BOPET film. [19] Film (1) according to one of the preceding claims, characterized by that the laser engraving has a depth of 5 µm to 30 µm and / or a track width of 15 µm to 50 µm due to the ablation. [20] Packaging container (K) comprising a film (1) according to one of the preceding claims and / or a film (1) produced according to one of the preceding claims. [21] Packaging container (K) according to one of the preceding claims, characterized by that he is: • Coffee capsule and / or • Tablet packaging and / or • blister pack and / or • Visible packaging and / or • Blister, in particular with a plastic molded part (5) for forming the interior (6) and the film (1) as the rear wall of the plastic molded part.

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