Patent Application
20250153906
The present application claims priority under 35 U.S.C. § 119 to German Patent Application No. DE 10 2023 131 387.8, filed Nov. 13, 2023, the disclosure of which is incorporated by reference herein in its entirety.
A molding tool for producing a lid made of a fiber-containing material, a lid made of a fiber-containing material and a molded part made of a fiber-containing material are described. Such lids and molded parts are used especially for beverage containers to close them and to leave only a small drinking opening free. Such lids and molded parts can also have pivoting components that make it possible to close the drinking opening.
Fiber-containing materials are increasingly used, for example, to produce packaging for food (e.g., trays, capsules, boxes, etc.) and consumer goods (e.g., electronic devices, etc.) as well as beverage containers. The fiber-containing materials usually contain natural fibers, which are obtained, for example, from renewable raw materials or waste paper. The natural fibers are mixed in a so-called pulp with water and optionally further additives, such as starch. Additives can also have an effect on color, barrier properties and mechanical properties. This pulp can have a proportion of natural fibers of, for example, 0.2 to 10 wt. %. The proportion of natural fibers varies depending on the method used for the production of packaging etc. and the product properties of the product to be produced.
In addition, lids made of a fiber-containing material are increasingly being used because they can be easily disposed of after use and do not pose a risk to the environment. Manufacturing processes for such lids include a wet process, where the lids are pressed from fibers that are suctioned out of an aqueous suspension and pressed into finished lids in one or more process steps under heat and pressure. Another method involves a dry process, where a relatively loose fiber composite (e.g. airlaid) with a low moisture content is pressed under high pressure and heat to form finished lids. Furthermore, such lids can be pressed into lids from a paper-like web under pressure. The above processes differ in the degree of deformation and thus in the possible design of the lids.
Containers that can be closed with such lids are often rolled and/or glued from a paper-like web, resulting in a raised area on the side wall and on the edge of the container, e.g. at the bond location. A lid that is connected to the container edge via a locking portion designed as an undercut, for example, cannot seal the entire surface of the container edge over the lid in the region of the raised area, with the result that the beverage can leak out during drinking, for example, due to the resulting lack of tightness. There is a high risk of injury here, especially with hot drinks.
The object is therefore to provide a solution where a secure seal for lids and molded parts, in particular made of a fiber-containing material, is provided that is particularly suitable for use in containers that have raised areas and similar uneven edge formations. In addition, the disadvantages of the prior art are to be eliminated.
The above-mentioned object is achieved by a molding tool for manufacturing a lid made of a fiber-containing material, having at least one mold cavity bounded by at least two tool parts that are movable relative to one another, where the mold cavity in the closed state forms at least one cavity for a lid to be manufactured, where at least one of the tool parts has at least one groove on a molding surface of the mold cavity, which groove extends at least partially over the molding surface of the tool part in the molding direction of the at least two movable tool parts.
With the molding tool, it is possible to manufacture a lid that has an additional sealing lip that seals a container edge, e.g. with a raised area, in addition to a locking (e.g. via an undercut) on an opposite side. The formation of a groove does not represent a restriction with regard to the tool design and has no effect on, for example, the formation of an undercut, because the groove runs in the direction of the mold.
The molding tool or at least a tool part can also be heatable. In further designs, channels can also be provided for the removal of steam during pressing, etc. The realization depends on the particular manufacturing process (dry, wet, paper-forming). In addition, in further designs, movable tool parts can be provided for the formation of undercuts and the like.
In further embodiments, the at least one groove can form a closed, substantially circular path. This can be used to create a circumferential sealing lip for a round lid.
In further embodiments, the at least one groove can have a transition radius in a transition to the mold surface. This prevents relatively thin sealing lips, which extend orthogonally from a corresponding surface on the inside of a lid, from being damaged during demolding.
In further embodiments, the transition radius can be between 0.1 and 3 mm.
In further embodiments, the groove can have a substantially semicircular cross-section. Such a design makes possible easy demolding of a lid after pressing and makes possible the formation of a sufficiently robust sealing lip.
In further embodiments, the radius of the substantially semicircular cross-section can have a radius of 0.5 to 5 mm.
In further embodiments, the mold cavity in the region of the at least one groove may have no undercut and/or may not be designed as a mold cavity for forming an undercut. This ensures that the sealing lip is designed as a material addition, i.e. that the sealing lip is not designed as an undercut or the like and only formed by deforming the corresponding region. A sealing lip is formed as an additional element on one side of a lid so that the opposite side of the lid can have a straight, flat surface.
The above-mentioned object is also achieved by a lid made of a fiber-containing material, having an edge that has a locking portion for locking to a container wall, and a side portion that is connected to the edge in a first region via a transition surface, where the side portion is connected to a closing lid surface in a second region, where the edge and the side portion have a different orientation with respect to the lid surface and/or to the transition surface, further comprising at least one sealing lip running on an inner side of the lid in a region of the transition surface, which is aligned concentrically with an axis running orthogonally through the lid surface and provides an additional holder with respect to the locking portion, where the at least one sealing lip and the locking portion are arranged opposite one another so as to come into contact with a container wall in the region of a container edge on opposite sides of the container wall.
The sealing lip, which can be designed as a web, is compressed from two sides when the lid is placed on the edge of the container. This can ensure a secure seal, in particular for containers with a variable edge formation (e.g. in the area of a bond location). Furthermore, an additional sealing is also achieved with a clear edge formation. In particular, the sealing lip can exert pressure on an edge of a container so that the container edge is pressed against the locking portion. The locking portion can have an undercut. This makes it possible to press the edge of a container against an undercut, further improving the seal.
In further embodiments, the locking portion and the at least one sealing lip can be aligned substantially parallel to each other.
In further embodiments, the at least one sealing lip can be designed as a material addition and the opposite portion of the transition surface on an outer side of the lid can be flat.
In addition, the object is achieved by a molded part made of a fiber-containing material, having an edge that has a locking portion for locking onto a container edge of a container, and a lid surface, where the edge has a locking portion in a transition to the lid surface and the locking portion has an undercut, where the edge has a different orientation compared to the lid surface, further comprising at least one sealing lip running on an inner side of the molded part in a region of the lid surface, which is aligned concentrically with an axis running orthogonally through the lid surface and provides an additional holder relative to the locking portion, where the at least one sealing lip and the locking portion are arranged in such a way as to come into contact with a container edge at least on substantially opposite sides.
Such a molded part can be designed as a lid and can be used to close, for example, beverage containers, tubs (e.g. for butter, spreads, etc.) and non-food containers. In particular, containers containing contents that may leak or otherwise escape (e.g. trickle out) require secure closure by means of a lid or the like. The described embodiment with an additional sealing lip makes it possible to completely seal a container edge over an entire circumferential surface, where, for example, the container edge is not only additionally in contact with another sealing contact surface via the sealing lip, but is also pressed into the undercut. Since the sealing lip projects inwards from the lid surface, it can be deflected or spring sideways to a small extent without the sealing lip being destroyed. This improves the sealing effect, in particular when the container edges are not evenly formed. Even if there are deviations in the molded part, an improved sealing effect is achieved without having to adhere to very tight manufacturing tolerances.
In further embodiments, a longitudinal extension of the sealing lip from the inside can substantially correspond to a radius of the undercut. This ensures, for example, that the sealing lip does not make demolding difficult during manufacture because sufficient mobility is provided for the undercut.
In further embodiments, the length extension of the sealing lip from the inside can substantially correspond to twice the radius of the undercut.
In further embodiments, the sealing lip can form an extension of a receiving groove formed by the undercut, whereby the contact area between the container edge and the molded part is significantly increased. The undercut and sealing lip form a circumferential groove on the inside of the molded part in the region of the locking portion.
Further features, embodiments and advantages result from the following illustration of exemplary embodiments with reference to the figures.
In the drawings:
Various embodiments of the technical teaching described herein are shown below with reference to the figures. Identical reference signs are used in the figure description for identical components, parts and processes. Components, parts and processes that are not essential to the technical teachings disclosed herein or that are obvious to a person skilled in the art are not explicitly reproduced. Features specified in the singular also include the plural unless explicitly stated otherwise. This applies in particular to statements such as “a” or “one”.
The conventional lid 20 has, starting from the edge 21 with the locking portion 22, a transition surface 25 that extends over the cup edge 14 and is connected to a side portion 23 via a first region 24. The side portion 23 is connected to a lid surface 27 via a second region 26.
A substantially parallel extension can, as shown in the figures, refer to a region of an undercut in the locking portion 22, where undercuts or locking portions 22 usually have a curved surface or a curved course.
On the outer side 29 of the lid 20, this lid has no notch, taper, deformation or undercut in the region of the sealing lip 30. The sealing lip 30 is designed as a local reinforcement or material addition. In particular, in the transition surface 25, which extends between the edge 21 with the locking portion 22 up to a first region 24, no depression, recess or other is provided in the region of the sealing lip 30 on the upper outer surface of the lid 20 shown in
Furthermore, the cup edge 14 can be pressed against or into the undercut in the locking portion 22 via the sealing lip 30, so that the cup edge 14 is at least partially encompassed by the undercut, particularly if this edge is also round. This further improves the sealing effect and the hold. In particular, the contact area or the contact areas between the inner side of the lid 20 in the undercut and the outer surface of the cup edge 14 can thus be significantly increased. Furthermore, by providing a sealing lip 30, it can be ensured that the contact between the inner side of the lid 20 in the undercut and the outer surface of the cup edge 14 is maintained.
With the design of the lid 20, in addition to the improved sealing, even in the area of a bond location 16, a more secure hold of the lid 20 on the cup 10 is achieved, so that it is made more difficult for the lid 20 to fall off the cup 10. In addition, depending on the design of the cup 10 and in particular the design of the cup edge 14 and the inclination of the cup wall 12 in combination with a locking portion 22, e.g. undercut, a proper and secure locking of the lid 20 on a cup 10 can be supported, and a tactile (and also an acoustic) feedback can be provided due to the more perceptible locking. In further embodiments, a pressing-in of an undercut after locking can be supported by the sealing lip 30, which also provides feedback for proper locking.
The design of the edge 21, the side portion 23, the transition surface 25, the lid surface 27 and the regions 24, 26 can vary depending on the desired shape of a lid 20. Essential to the embodiment disclosed herein is the provision of a sealing lip 30, which provides additional sealing as compared to a lock.
As further depicted schematically in
The height or the dimension by which the sealing lip 30 projects downward into the interior of the lid 20 can, in the embodiments shown, correspond for example to the radius of an undercut.
In further embodiments, lids 20 can also have polygonal surfaces in the region of the lid surface 27 instead of a round, substantially circular extension of the lid surface 27. The transitions on such polygonal side portions can be rounded. Irrespective of the planar extension of the lid surface 27, a sealing lip 30 can extend partially or completely at a substantially uniform distance from a locking portion 22. In still further embodiments, containers, such as cups 10, can have locking portions 22 (e.g. with an undercut) only in some portions, where the sealing lip 30 is provided around the entire circumference.
The lids 20 described herein or also molded parts with a sealing lip 30 designed as a web made of a fiber-containing material and can be manufactured, for example, in a so-called wet process, where preforms made of a fiber-containing material can first be provided that are then pressed under the action of heat. The preforms can be prepared in such a way that fibers are suctioned out of an aqueous solution (pulp) and three-dimensional preforms are formed that substantially already have the shape of the products to be manufactured. In addition, additives such as starch, chemical additives, wax, etc. can be added to a pulp to influence the properties of the products to be manufactured (e.g. barrier properties) and the processability. The fibers can be, for example, natural fibers, such as cellulose fibers, or fibers from a fiber-containing original material (for example waste paper). Since a fiber-containing pulp with natural fibers is used as the starting material for the lids 20, the manufactured lids 20 can themselves be used as a starting material for the manufacture of lids 20 or other products after their use, or they can be composted, because they can usually be completely decomposed and do not contain any substances that are harmful to the environment.
In further embodiments, the preforms can be subjected to a pre-pressing step. The preforms are then pressed into three-dimensional lids 20 in a hot-pressing device under pressure and heat.
Furthermore, the lids 20 can be formed from a loose cellulose web (airlaid) or a paper.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10 2023 131 387.8 | Nov 2023 | DE | national |
