Three-dimensional molded part made of fiber-containing material and molding tool for the production of molded parts made of fiber-containing material

The present application claims priority under 35 U.S.C. § 119 to German Patent Application No. DE 10 2024 117 158.8, filed Jun. 18, 2024, the disclosure of which is incorporated by reference herein in its entirety.

A three-dimensional molded part made of fiber-containing material and a molding tool for producing molded parts made of fiber-containing material are described.

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 can have natural fibers, which are obtained, for example, from renewable raw materials or waste paper. The natural fibers can be mixed in a so-called pulp with water and, optionally, further additives, such as starch, and then formed. Additives can also have an effect on color, barrier properties and mechanical properties. A pulp can have a proportion of natural fibers of, for example, 0.1 to 10 wt. %. The proportion of natural fibers can vary according to the method used for the production of packaging, etc., and the product properties of the product to be produced. Fibers, such as natural fibers, can also be introduced into molding tools in a dry state and processed or formed therein. Alternatively, such fibers can be processed into starting materials for subsequent shaping. Starting materials for further processing can, for example, be so-called webs or sheets, such as airlaid, fluff pulp, paper, etc., as well as multi-layer arrangements made of the above materials, made of a fiber-containing material, which are then formed in a molding tool.

During the production of products or molded parts from a fiber-containing material, the evaporating water is extracted as standard during a pressing process at high temperatures and high pressure in a so-called wet process. Even in dry molding processes, the so-called dry process, steam can be extracted during a pressing process with high temperatures and high pressure if the fiber-containing material has a water content of about 20 wt. % or more or has at least been locally moistened. To extract the steam, the molding surfaces of molding tools have small openings that are connected to corresponding channels and devices. During the pressing process, small elevations form on the surfaces of the molded parts, with the fiber-containing material being pressed into the openings. Extraction can support the formation of elevations.

Such elevations arise as a result of extraction, where with increasing moisture content of the material to be pressed in cavities of molding tools, more and more steam is generated, which must be discharged via openings on at least one molding surface of a molding tool. The elevations are perceptible both visually and haptically on a finished molded part.

However, the elevations are perceived as disruptive with regard to design specifications and aesthetic aspects, so that the demand for alternative molded bodies made of renewable and easily recyclable fiber-containing materials, which can also be compostable, is very low. This is a crucial disadvantage, especially with regard to the goal of using more sustainable products. In addition, such elevations have the disadvantage that when used, for example as a capsule for a coffee machine or as a lid for a drinking cup, they do not sit flush with contact surfaces (e.g., brewing chamber for a coffee capsule) or do not fit optimally against the edge of a cup, so that a sufficient sealing effect cannot be achieved. Furthermore, such elevations on a lid can make drinking difficult.

By contrast, it is an object to provide a solution that eliminates the disadvantages of the prior art and enables the formation of molded parts from fiber-containing material and provides molded parts from fiber-containing material that are simply designed, are not subject to any functional restrictions in the use of molded parts due to elevations resulting from the manufacturing process and take aesthetic requirements into account.

The above-mentioned object is achieved by a three-dimensional molded part made of fiber-containing material, which is produced in a production process under pressure and thermal influence, where a surface of the molded part has at least one elevation that is formed by fiber-containing material that, during the production of the molded part, has been suctioned and/or pressed into a corresponding opening in a molding surface of a molding tool when steam that escapes from the fiber-containing material during pressing is removed, and where the at least one elevation is arranged in a first surface portion that has a different configuration than an adjacent at least one second surface portion, where the at least one elevation is integrated into the configuration of the first surface portion.

When integrating the at least one elevation into a first surface portion with a configuration that differs from a second surface portion, the at least one elevation is integrated into a portion or region (first surface portion) of a surface of the molded part that already differs in its configuration (shape, depth, thickness, etc.) and thus also visually and haptically from the remaining surface region or neighboring regions (second surface portion). This ensures that the at least one elevation does not have a disturbing visual appearance because it is integrated into a region that is already formed differently for design and/or technical reasons, and is not disturbing when using the molded part because the at least one elevation does not protrude from a contact surface or plane due to its integration into a differently formed region, for example, so that no “locking points,” “spacer knobs” or the like are formed.

For example, elevations can be provided in regions of a molded part with reduced material thickness, so that no elevations protrude from the surface to the extent that the elevations in the regions with reduced material thickness protrude at most to such an extent that their protruding ends are substantially flush with the surface profile of the surrounding regions of the second surface portion. In other words, elevations cannot protrude above a surface plane that extends over the first surface portion and the second surface portion.

Furthermore, elevations can also protrude deliberately from a surface plane, where the elevations are part of a configuration.

The different configuration of the at least one first surface portion can be formed in different ways. For example, the configuration can include transitions, general elevations, i.e., thickened regions, design elements, depressions, formation elements, etc. The at least one elevation can be provided in a first surface portion on an outer surface and/or inner surface. The elevations themselves usually extend perpendicularly from the surface and have small dimensions. For example, elevations can have diameters of 0.5 to 2 mm or corresponding cross sections. The height of elevations can, for example, be in the range of 0.2 to 1.5 mm. The dimensions may also be designed according to the layer thickness of the molded part in the region of the material layer assigned to the surface and the dimensions of the molded part as well as the material used and the intended use and may deviate from the above exemplary dimensions. Molded parts can be designed in different ways and, for example, have a round or polygonal cross section.

In further embodiments, the surface of the molded part can have at least one design element that is formed by at least one region with reduced material thickness, where the material thickness of the at least one region decreases with an increasing molded part height in a molding direction. At least one elevation can be integrated into this region so that the elevation does not protrude from a surface plane.

In further embodiments, the molded part can have at least one first elevation and at least one second elevation, where the at least one first elevation and the at least one second elevation differ from one another in their configuration.

The molded part can also have a plurality of first surface portions, each of which has at least one elevation, where the elevations and/or the first surface portions can each be formed differently.

In further embodiments, the configuration of the first surface portion can be formed by a change in at least one of a surface type, orientation, arrangement, structure, material type and profile compared to the at least one second surface portion, and/or by a marking and/or a formation element. This also includes regions with reduced material thickness. In particular, this may include depressions, transitions between edge, side and/or base regions, embossing, etc.

In further embodiments, the first surface portion may include a region with product features, product representations, instructions for use of a product and/or disposal of the molded part. For example, symbols, letters, numbers, etc. can be formed by depressions, protruding regions and other surface characteristics (e.g., structure, roughness, etc.), where the at least one elevation is integrated in such a surface portion.

In further embodiments

In further embodiments, the at least one elevation can have an at least in portions oval, elongate, polygonal or round cross section. The at least one elevation can be part of a design element or can constitute a substantial component thereof. In further embodiments, for example, several elevations can also form a pattern on the surface, which pattern in further embodiments takes into account purely optical aspects, contains information and/or represents a functional element that serves, for example, as a spacing element, guide element and/or marking.

In further embodiments, the at least one elevation itself can be formed as a design element.

In further embodiments, the at least one elevation can be formed as a functional element. A functional element can, for example, be a so-called undercut. Undercuts are provided, for example, on lids and the like to enable the gripping behind a container edge (bowl, cup, etc.) or a corresponding undercut, whereby a secure closure can be achieved. In addition, an acoustic feedback can be provided by a “snap” when closing. When the at least one elevation is designed as a functional element, for example as an undercut, the at least one elevation can have an elongate extension and, in further embodiments, can extend, for example, at least in portions around an edge or side region. A functional element, e.g. an undercut, which is formed by an elevation, can also reinforce a functional element formed by molding. For example, an undercut can be created in a molded part using a corresponding shape, whereby the undercut, i.e., the depth of the functional element, is reinforced or enlarged by an elevation.

A correspondingly designed molding tool for such a functional element can, for example, have an elongate opening or several openings on a molding surface for steam removal, which are designed, for example, as a slot or a series of slots/openings. For example, steam escaping during pressing can be extracted through the slot, with additional fiber-containing material being suctioned into the slot. After pressing, the fiber-containing material suctioned into the slot then forms a ring-like or ring-segment-like elevation, which forms a protruding functional element that acts like an undercut. Of course, other functional elements can also be designed, such as holding or spacer ribs (e.g., for containers for hot or cold food/drinks) or as a rough gripping surface with a plurality of elevations.

In further embodiments, the fiber-containing material may include at least 50 wt. % of plant fibers and/or cellulose fibers.

The above-mentioned object is also achieved by a molding tool for producing molded parts according to any of the above embodiments, where the molding tool has at least one molding surface for pressing fiber-containing material to form a three-dimensional molded body, where the at least one molding surface has at least one opening for discharging steam from fiber-containing material during a pressing process, where the at least one opening is arranged in a region that forms a transition between at least two surface portions, and where the at least one opening is integrated into an embossing region of the at least one molding surface for at least a first surface portion of the molded part.

The molded parts specified above with regard to the molded part also apply accordingly to a molding tool for producing such molded parts, where molded parts can be produced using simple means without a complex and vulnerable tool design, which fulfills the above requirements and solves the problem mentioned at the outset.

Further features, embodiments and advantages result from the following illustration of exemplary embodiments with reference to the figures.

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 substantial 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.”

depicts a schematic representation of a molded partmade of fiber-containing material in a perspective view. The molded partdepicted inis designed as a capsule. In the embodiment shown, the capsule is designed as a coffee capsule and is used to hold coffee powder. Before filling and after the production of the molded partdepicted in, a coating (lamination, coating, etc.) of an inner receiving space or an inner surface can be carried out to provide a barrier. Alternatively or additionally, after filling and sealing, the capsule may be subjected to a covering (lamination, coating, etc.) on its outer surface in order to achieve a barrier effect. Another alternative or additional possibility for providing barrier properties for a molded partmay be the introduction of additives into the fiber-containing material.

The molded parthas a basethat has a base ring. The base ringprotrudes from the surface of the base. The molded parthas an adjoining circumferential side wall. The side wallis slightly inclined relative to the base, where the diameter of a receiving space of the molded partincreases from the baseto an edge. In the exemplary embodiment shown, the molded partis substantially rotationally symmetrical. The side wallhas a thickened or stepped ring. In the region of the ring, the material thickness or the thickness of the side wallcan be stronger or greater than in the remaining region. Alternatively, the cross section or diameter of the side wallmay increase in the region of the ringin order to provide a substantially constant wall thickness over the entire side wall. A second transitionhaving a radius is formed between the ringand the side wall. A first transitionfrom the ringto an edgealso has a radius. In the embodiment shown, elevationsare formed at various locations on the surfaceof the molded part.

Three design elementsare integrated into the side walland are formed during the pressing of the fiber-containing material in a molding tool(see, for example,). The design elementsare designed as coffee beans in, since the embodiment represents a capsule for coffee. It is evident that other design elementscan also be created by appropriate shaping and design of the surface. The design elementshave a regionwith reduced wall thickness, as described in more detail with reference to. The side wallforms a second surface portionon its surface, which here has a curved profile. The portions with the design elementsform first surface portions.

In the embodiment according to, elevations, which are formed during a molding process during the hot pressing of fiber-containing material due to the removal of steam that escapes from the fiber-containing material during pressing under high pressure (0.2 to 300 N/mm) and high temperatures (120-300° C.), via corresponding steam holes (openings; see, e.g.,) in molding surfacesof a molding tool, are integrated into the embodiment of the first surface portionsor design elements.

By integrating the elevationsinto the embodiment of the design elements(“coffee bean”), these elevationsare barely perceptible and blend in with the embodiment both visually and haptically. In the exemplary embodiment with the coffee bean, the design elementhas a webin the first surface portion. The webprotrudes from the neighboring regions, each of which has a smaller material thickness or wall thickness than the weband the second surface portion. The elevationson the websare thus integrated into the different embodiment of the design elementcompared to the second surface portion.

Furthermore, elevationsare integrated into the transitions,and a transition region between the base ringand the baseor into the base ring, so that these elevations do not have a significant influence on the use of the molded part, i.e., they do not form any protruding elements that are arranged on visible surfaces on the surfaceor that are disruptive to abutment against corresponding surfaces of a utilization machine (e.g., coffee machine). The elevationson the baseand on the edgemay also be omitted in further embodiments. In the exemplary embodiment, these are shown as an embodiment option on further first surface portions that differ from the remaining surface, in particular the surfaceof the side wallin the second surface portion, due to the orientation and arrangement as well as the surface characteristics. The basehas, for example, a surface offset from the base ring, so that the central elevationsdo not interfere with the use of the molded partand are also barely perceptible. The edgehas a rougher surface, so that the elevationson the edgeare barely perceptible both visually and haptically and are also not located on relevant functional surfaces, in particular for later use (e.g., coffee machine).

depicts a schematic representation of another molded partmade of fiber-containing material in a perspective view. In the embodiment shown, a plurality of elevationson the surface of the side wallform a pattern, as shown schematically by the dashed line. A patternmay also extend beyond the side wallto the edgeand/or the base. In further embodiments, the baseand/or the edgemay also have a patternof several elevations. Instead of a curved profile, as shown in, a patterncan also form a letter, a number, a character or a corresponding letter, number and/or character string.

depict schematic representations of the formation of a design elementon the surface of a molded partmade of fiber-containing material, the formation on an outer surfacebeing described here. In further embodiments, an analogous embodiment can also be provided on an inner surfacewith a corresponding inclination of a side wall.

depicts both a design elementformed as a coffee bean and a section through the design element. The design elementis formed by at least one regionwith reduced material thickness, where the material thickness of the at least one regiondecreases with an increasing molded part height FH in a molding direction FD.

The design elementhas a regionwith reduced material thickness or wall thickness, as can be seen in particular in the sectional view. In a first sub-region, the side wallhas a decreasing material thickness in the region of the design element, which decreases further up to a second sub-regionand reaches its maximum. The material or wall thickness along the webremains unchanged in the exemplary embodiment. In further embodiments, the material or wall thickness of the webcan also decrease, where the degree of decrease can be different from the regionsin order to achieve a visually and haptically perceptible difference between regionsand a web. This may be necessary in particular if, for example, a webhas a profile that, during demolding, collides with the molding surface of a molding tooland could be damaged in the process.

In further embodiments, the formation of a step in the first regionrelative to the outer surfacecan be tolerated in order, for example, to achieve a delimitation between the first regionand the surface. Such a step can form an undercut in a molded part. Up to a certain depth (e.g., 1 mm) or undercut formation, demolding can thus take place after the molding process in a molding tool without moving parts, without damaging the molded part.

As depicted in, the material thickness increases with increasing molded part height F(see), so that demolding can take place without the need for additional movable molded parts to be moved on a molding surface of a molding tool part and, for example, orthogonal to a molding direction F. The formation of design elementsis created here by increasingly thinner regions.

depicts a further variant for a design elementformed as a coffee bean, where elevations are formed along the web. For this purpose, the design elementcan have regionswith a lower material thickness, analogous to the embodiment according to, where the material thickness can also decrease with increasing molded part height Fas in.

In addition, the material or wall thickness of the webcan also decrease or an elevationcan be provided in a sub-regionorso that the elevationdoes not protrude or only protrudes slightly from the overall surface or the surface of a second surface portion, as depicted schematically in, for example.

depicts a schematic representation of a sectional view of a molded partmade of fiber-containing material with differently formed elevationsand design elements.

The molded partis shown, like the molded partsfrom, in an orientation advantageous for production, where the molded part height FH is determined from the base. The individual elevationsare shown on both an outer surfaceand an inner surfacein order to schematically show the possible positions for elevations. Furthermore,depicts the integration of elevationsin transitions, where the transitionshave a radius that is, for example, in the range of 0.2 to 5 mm. As depicted inon the right side of the molded part, a circumferential groove or a local depression is formed in the transition, in which an elevationis integrated, so that the elevationhardly protrudes from the outside and is therefore neither visually nor haptically perceptible and/or is not detrimental to a function or use. Thus, in further embodiments, elevationscan be accommodated in depressions (grooves, craters, etc.), where the elevationsthus do not protrude, or only slightly protrude, beyond the surface of the surrounding second surface portions.

On the right side, the side wallof the molded parthas two regionswith reduced wall thickness, where one region has a webor an element designed analogously thereto, on which the elevationsare formed and protrude from the design element(lower example), or the elevationsare arranged in, for example, a sub-regionwith a small material thickness, so that the elevationdoes not protrude above the surface of the surrounding second surface portion(upper example).

depicts schematic representations of the formation of elevationsand design elementson surfaces,of a molded part. In this case, elevationsmay not only be circular, but may also have an elongate and/or curved profile. Polygonal cross sectional shapes are also possible and can be realized by a corresponding design of openingsfor extracting steam in the molding surfaces of molding tools.

Elevationscan be components of a design elementand follow a profile of elements (e.g. a web), or can themselves be a design element, e.g. a letter (“L”).

In further embodiments, character strings or symbols can also be realized by several appropriately designed elevations, which, for example, give a consumer an indication of use or disposal.

depict schematic representations of a molded partwith elevations, which are designed as functional elementsin. The functional elementsserve to form an undercut. In the figures, the molded partsare designed as a lid, which can be placed, for example, on a cup. To ensure that the lids are securely held on a cup, e.g., on a bead-like edge of a cup or the like, they have an undercut. In, a side wallis already formed with an inwardly tapering side wall portion that forms an undercut. To reinforce the undercut, the elevationsare located in this side wall portion, so that the elevationsform functional elementsthat reinforce the undercut, where the inner diameter is further reduced and thus a holding effect on an edge is improved.

In, the elevationsare located on an inner sideof the side wall. The functional elementscan be designed as webs with a freely selectable width or as a continuous elevation, as shown, for example, in.depicts a molded partdesigned as a lid with a substantially parallel aligned side wall, which has a circumferential elevationas a functional element(undercut) on the inner side, where the undercut is formed here only by the elevation.

The elevationscan, for example, be formed by short portions or longer portions, as indicated in. Alternatively, a functional elementcan be formed by a closed elevation.