Three-dimensional molded body and method for producing three-dimensional molded body of fiber-containing material

Abstract

A three-dimensional shaped body (10) made of fibrous material and a method for producing a three-dimensional shaped body (10) made of fibrous material are described, wherein the shaped body (10) has a circumferential side wall (14) that surrounds an interior of the shaped body (10), wherein the side wall (14) has a degressive profile at least section by section from an edge region (16) to a bottom region, wherein the cross-section of the side wall (14) in the bottom region is smaller than the cross-section in the edge region (16).

Description

Technical field

[0001] A three-dimensional shaped body made of fibrous material and a method for producing a three-dimensional shaped body made of fibrous material are described. background

[0002] Fiber-containing materials are increasingly used to manufacture packaging for food (e.g., trays, capsules, boxes, etc.) and consumer goods (e.g., electronic devices, etc.), as well as beverage containers. These fiber-containing materials can contain natural fibers, which are obtained, for example, from renewable resources or recycled paper. The natural fibers can be mixed with water and, if necessary, other additives such as starch in a pulp and then shaped. Additives can also affect the color, barrier properties, and mechanical properties. A pulp can contain, for example, 0.1 to 10% by weight of natural fibers. The proportion of natural fibers can vary depending on the manufacturing process used for the packaging, etc., and the product properties of the product being manufactured. Fibers such as...Natural fibers can also be introduced into molds in a dry state and processed or shaped within them. Alternatively, such fibers can be processed into raw materials for subsequent shaping. Raw materials for further processing can include, for example, sheets or webs, such as airlaid, fluff pulp, paper, etc., as well as multi-layer arrangements of the aforementioned materials, made from a fiber-containing material, which are then formed in a mold.

[0003] Manufacturing processes for products or molded parts made from a fiber-containing material include a wet process, in which the molded parts are pressed from fibers that are drawn from an aqueous suspension and pressed into finished parts in one or more process steps under heat and pressure. Another process involves a dry process, in which a relatively loose fiber composite (e.g., airlaid) with low moisture content is pressed into finished parts under high pressure and heat.

[0004] In the processing of such molded parts, they are stacked in a subsequent processing step, for example, for transport or similar purposes, after forming. For instance, it is known to stack thermoformed plastic cups after molding for subsequent transport, whereby the space required for transporting a large number of cups is significantly reduced when stacked. The cups can then be easily separated from one another, with individual cups being removed from the inside or outside of the stack. The plastic material of the cups allows, for example, the side walls of the cups to slide easily against each other. When stacking, for example, cups or capsules made of a fibrous material, there is also a desire to stack them after production in order to have a relatively small footprint during transport or storage.Stacking cups or similar items made of fibrous material proves difficult and sometimes even detrimental, as the properties of the fibrous material cause the cups to stick together strongly at the contact points, increasing friction between the fibers or the fibrous material itself. Consequently, removing cups or similar items from a stack requires considerable force, and this can also lead to damage. Because the cups are intentionally designed to be as identical as possible, they are in contact with each other over a relatively large surface area.

[0005] This means that the known designs of molded parts made from a fibrous material have the disadvantage that they cannot be stacked or can only be stacked very poorly and subsequently unstacked without requiring a great deal of force and / or the molded parts being damaged during unstacking. Task

[0006] The task is therefore to provide a solution that overcomes the disadvantages of the prior art, in particular enabling molded parts made of a fibrous material to be stacked and unstacked easily and without damage. Solution

[0007] The aforementioned problem is solved by a three-dimensional shaped body made of a fibrous material, having a circumferential side wall that surrounds an interior of the shaped body, wherein the side wall has a degressive profile at least section by section from an edge region to a bottom region, wherein a cross-section of the side wall in the bottom region is smaller than a cross-section in the edge region.

[0008] Such a molded body offers a solution for easy stacking and unstacking when the molded body is made of a fibrous material, by reducing the contact area of ​​stacked molded parts, such as cups, capsules, etc.

[0009] The reduction of the contact area is achieved by the sidewall having a degressive profile from the edge region downwards to a base area. The resulting change in cross-section allows molded parts, such as cups or capsules, to be stacked relatively deep within each other, whereby, despite the large overlap of adjacent sidewalls of at least two molded parts, the contact area is significantly reduced compared to known designs. The overlap is defined by the area in which the sidewalls of nested molded parts are in contact.

[0010] The degree of the degressive curve defines the size of the contact areas between the side walls of stacked molded parts.

[0011] Additionally, molded parts can have an edge that extends orthogonally or in a projecting arrangement from the mold body in the edge region, thus preventing excessive sliding inwards or excessive stacking. This allows the contact area or maximum contact area between the side walls of stacked molded parts to be limited or defined.

[0012] The degressive shape of the sidewall therefore allows for the stacking of fiber-containing molded parts, whereby the influence of the fibers and the resulting friction or adhesion effect of adjacent sidewalls is reduced.

[0013] Another advantage of such a degressive profile is the easier unstacking compared to purely conical molded parts, because the contact area or mating surface of two nested molded parts is located near the edge. This also reduces jamming, which can occur, for example, near the base of purely conical molded parts, because in the area with the larger cross-section the molded part can be compressed more easily or more readily and thus is more susceptible to friction or adhesion.

[0014] Another advantage of a degressive curve can arise when using three-dimensional molded parts made of a fibrous material, particularly when these need to be inserted into and subsequently removed from corresponding receptacles after filling. For example, a degressive curve can facilitate the removal or ejection of coffee capsules made of a fibrous material from a coffee machine's receptacle, as the force required for ejection can be kept essentially constant.

[0015] The cross-section of at least the interior of the molded part can be round (circular, elliptical, oval) or polygonal (triangular, square, pentagonal, etc.).

[0016] The degressive curve can be more or less pronounced along the side wall or in sections of the side wall.

[0017] In further versions, the degressive curve can extend from the bottom area to the edge area, so that the side wall has a degressive curve over the entire height of the interior, which further facilitates stacking and unstacking.

[0018] In further versions, the degressive curve along the side wall can be divided into sections of equal length for each definable distance, whereby the gradient of at least two consecutive sections is different from each other.

[0019] In further embodiments, the cross-section or diameter of the interior along the side wall can decrease by a factor of 0.4 to 0.9 per definable distance from the edge area, with sufficient stability of the molded body prevailing in this area with minimal contact area in the stacked state of molded bodies.

[0020] In further versions, the definable path can be defined parallel to the height of the interior or along the surface of the side wall.

[0021] Depending on the definition of the path length across the height of the interior or along the side wall, the cross-section or diameter can decrease by a definable amount per path segment, which is, for example, within the range specified above.

[0022] In further embodiments, the side wall can have a straight and a curved profile in sections, whereby in sections of the side wall that follow a contact area of ​​stacked molded parts, the profile can again be straight, provided that no additional contact point is thereby created.

[0023] In further embodiments, the edge area can have an undercut that further supports stacking and unstacking, reducing the contact area in the stacked state of the molded body in the edge area.

[0024] In further embodiments, the molded part can have a stacking shoulder at the transition between the edge region and the side wall. When edges are formed in an edge region, these can, for example, have an annular section that forms an additional stacking shoulder, particularly at the transition from the side wall to the annular section. The stacking shoulder can determine how far molded parts can be stacked into one another. Thus, the stacking shoulder serves as a limiting element. If an undercut is provided in the area of ​​the stacking shoulder, preferably above the stacking shoulder and extending from the transition between the annular section and the side wall, the contact area in the area of ​​the annular section is reduced by the undercut, so that a stacking shoulder can be provided in a molded part without the disadvantages of the prior art.This allows, in particular, the provision of a limiting element for stacking, whose contact surfaces are limited to a minimum and the function of the limiting element is restricted to the essential component.

[0025] In further versions, the undercut can have an increasing cross-section from an upper section of the edge area to a lower section of the edge area towards the floor surface.

[0026] In further embodiments, the degressive curve can be designed such that when stacking three-dimensional molded parts, contact occurs only along the lines between at least two stacked three-dimensional molded parts in the area of ​​adjacent side walls. This line contact is defined by an outer circumferential line that runs essentially parallel to a base surface or the base area of ​​the molded parts. In such embodiments, the at least two molded parts can only be in contact with each other between their side walls via an annular contact area. This means the contact area is reduced to a minimum, making unstacking very easy.

[0027] The aforementioned problem is further solved by a method for producing a three-dimensional molded body according to one of the preceding descriptions, comprising Providing a fibrous material, introducing the fibrous material into a mold of a molding tool; closing the molding tool by relative displacement of the mold and a corresponding mold element, and pressing the fibrous material into a three-dimensional molded body, forming at least a sectionally degressive gradient in a side wall of the molded body.

[0028] Further features, designs and advantages will become apparent from the following presentation of exemplary embodiments with reference to the figures. Brief description of the characters

[0029] The drawings show: Fig. 1 a schematic representation of a molded part in a sectional view; Fig. 2 a schematic representation of stacked molded parts in a sectional view; Fig. 3 another schematic representation of a molded part; Fig. 4 a schematic representation of another molded part in a sectional view; Fig. 5 an enlarged view of a section of the molded part of Fig. 4 ; Fig. 6 a schematic representation of further stacked molded parts in a sectional view; Fig. 7 an enlarged representation of the contact area in the stack shoulder of the molded parts of Fig. 6 Fig. 8 shows a schematic representation of further stacked molded parts in a sectional view; Fig. 9 shows an enlarged view of the contact area in the stack shoulder of the molded parts. Fig. 8 ; and Fig. 10 an enlarged view of the contact area between the side walls of the molded parts of Fig. 8 . Detailed description of implementation examples

[0030] The following are exemplary embodiments of the technical teaching described herein, with reference to the figures. The same reference numerals are used in the figure descriptions for identical components, parts, and processes. Components, parts, and processes that are immaterial to the technical teaching disclosed herein or that are obvious to a person skilled in the art are not explicitly shown. Features given in the singular are also included in the plural unless explicitly stated otherwise. This applies in particular to terms such as "a" or "an".

[0031] Fig. 1Figure 1 shows a schematic representation of a molded part 10 in a sectional view. The molded part 10 can be, for example, a bowl, cup, capsule, etc., and consists of a fibrous material or has fibrous material as its predominant component. The fibrous material can, for example, consist predominantly of natural fibers. The fibrous material can contain additives that influence the properties of the molded part 10 with regard to barrier properties, mechanical properties (strength, etc.), color, printability, etc.

[0032] The in Fig. 1The molded part 10 shown has a base area 12, which can serve as a support surface for the molded part 10. A circumferential side wall 14 extends from the base area 12. A rim area 16 with a ring 15 and a border 17 adjoins the side wall 14. In a transition 24 from the side wall 14 to the rim area 16, the molded part 10 has a stacking shoulder 30. The molded part 10 has a circular cross-section and can be rotationally symmetrical. In other embodiments, the cross-section can be polygonal.

[0033] For easier stacking and unstacking of such molded parts 10, the in Fig. 1 The molded part 10 shown exhibits a degressive profile in the side wall 14, such that the cross-section or diameter decreases progressively with increasing distance from the edge region 16 towards the base 12. This ensures that, in the stacked state of the molded parts 12, a contact area 20 (see Fig. 2) between two side walls 14 can be reduced to a necessary minimum. This reduces the surface area of ​​the side walls 14 that lie against each other and are in direct contact with each other when stacked. Previously, the contact area of, for example, cups from the prior art, which consist of a fibrous material, was relatively large and could extend almost over the entire side wall surface. This meant that a relatively large force had to be applied during stacking because the contacting side walls exhibited strong friction or adhesion due to the fibrous material. Similarly, with the known design of molded parts, a high force is required to unstack nested molded parts. Furthermore, in the prior art, the forces required for stacking and unstacking depend on the overlap of the side surfaces 14 or...The stacking depth is dependent on the stacking depth, and the stacking and unstacking must be adjusted during the stacking and unstacking process to reduce damage to the molded parts. Therefore, with the known design of molded parts, stacking and unstacking is only possible with considerable effort, and damage due to adhesion or friction of the side walls caused by the fibrous material is always present.

[0034] The degressive shape of the cross-section or diameter of the molded part 10 in the shown embodiments allows a reduction of the contact areas, thereby reducing the effect of adhesion between molded parts 10.

[0035] The molded part 10 additionally has an undercut 18 in the edge region 16. The undercut 18 is located in a ring 15 that adjoins the stacking shoulder 30. The stacking shoulder 30 is formed in the transition 24 between side wall 14 and ring 15 (see, for example, the figure). Fig. 5). In the area of ​​the stacking shoulder 30, the molded part 10 can exhibit a significant change in cross-section or diameter compared to the side wall 14. Fig. 1 Figure 1 shows, in particular, a schematically pronounced change in diameter for illustration purposes. The stacking shoulder 30 creates a contact surface 32 on the outside of the molded part 10 for a corresponding area or a contact surface 34 of another molded part 10. Such a design is particularly common in the Fig. 6 , 7 and 9shown, wherein, in addition to contact between at least two molded parts 10 at their side walls 14, a first molded part 10 is in contact in a contact area 22 via its contact surface 32 on the outside of the stacking shoulder 30 with a contact surface 34 on the inside of a second molded part 10 at the transition from the ring 15 to the edge 17. A further molded part 10 inserted into the molded part 10 rests with its stacking shoulder 30 at the transition from the ring 15 to the edge 17, as e.g. in Fig. 2 shown. By different shaping of the radii on the inside and outside in the area of ​​the stacking shoulder 30 or in the transition from edge 17 to ring 15, the bearing surface or contact area 22 ( Fig. 2 ) can be further reduced, whereby the radius on the inside can be larger than the radius on the outside of the molded part 10.

[0036] The formation of the edge 17 in the border region 16 can, for example, in Fig. 1shown, orthogonal to the vertical axis H, or curved, trough-like, etc.

[0037] Fig. 2 Figure 1 shows a schematic representation of stacked molded parts 10 in a sectional view. The molded parts 10 essentially correspond to those previously described with reference to Fig. 1 as shown. The contact area 20 between the side walls 14 of the molded parts 10 and the contact area 22 between the edge areas 16 or stacking shoulders 30 of the molded parts 10 are reduced compared to molded parts from the prior art, so that the disadvantages due to the fibrous material and its properties are also reduced.

[0038] Fig. 3Figure 1 shows a further schematic representation of a molded part 10 and an exemplary implementation of a degressive curve. Sections A1 to A5 and A'1 to A'5 are defined along the vertical axis H of the molded part 10. Sections A1 to A5 divide the side wall 14 into equal sections running parallel to the vertical axis. With increasing distance from the edge region, the curvature of sections A1 to A5 increases in sections A'1 to A'5, so that the deflection increases orthogonally to the vertical axis H. Accordingly, the length of sections A'1 to A'5 increases with increasing distance from the edge region 16 towards the base 12.

[0039] The degressive curve can describe a branch of a parabola, whereby in further embodiments the branch of the parabola can be rotated around a pivot point D. The pivot point can, in particular, be located in a section of the side wall 14 that is closer to the edge region 16 than to the base 12. Fig. 3 An example position for a pivot point D is shown.

[0040] Fig. 4 Figure 1 shows a schematic representation of another molded part 10 in a sectional view. Molded part 10 differs from the other versions shown in its shape, but also features a degressive sidewall profile for a sidewall 14 and an undercut 18 extending from a stacking shoulder 30 into a ring 15 of an edge region 16, as shown in Figure 1. Fig. 5 shown in detail.

[0041] The degressive profile of the side wall 14 is shown by a straight line g, which runs at a distance from the side wall 14 at its lower end, at the level of the base 12. At the level of the base 12, the straight line g forms an angle α with the outer surface of the molded part 10 relative to the side wall 14, which can be in the range of 0.5° to 25°. Preferably, the angle α is approximately between 1° and 15°.

[0042] Fig. 5 shows an enlarged view of a section of mold part 10 of Fig. 4 in the edge area 16. In particular, a embodiment of the stacking shoulder 30 and the ring 15 is shown. The undercut 18 can be, as in Fig. 5 The undercut 18, shown in the figure, has a negative profile with respect to a forming and demolding direction that runs in the direction of the vertical axis H. In the region of an inner edge surface 19, the undercut 18 has a profile defined by a straight line h, which, starting from a starting point P of the undercut 18, is inclined at an angle β to a straight line p running parallel to the vertical axis H. The angle β can be in the range of 0.5° to 10°. Preferably, the angle β is approximately between 0.5° and 2°.

[0043] The undercut 18 ensures that the contact area 22 in the edge region 16 is reduced compared to prior art molded parts. Fig. 5A design of the contact areas 22 is shown, which includes the contact surface 32 on the outside of the stack shoulder 30 and a contact surface 34 in the transition between ring 15 and edge 17, wherein a contact surface 34 of a further molded part 10 can come into contact with the contact surface 32 and a contact surface 32 of yet another molded part 10 can come into contact with the contact surface 34 and wherein the contact surfaces are thus reduced.

[0044] Fig. 6 Figure 1 shows a schematic representation of further stacked molded parts 10 in a sectional view, wherein the arrangement of two molded parts 10 is shown by the special design of the stacking shoulder 30. Fig. 7 Figure 1 shows an enlarged view of the contact area 22 between a contact surface 32 on the outside of the stacking shoulder 30 of a molded part 10 and a contact surface 34 in the transition between a ring 15 and an edge 17 of the molded parts 10. Fig. 6The undercut 18 enlarges, as schematically shown, an area between an edge surface 19 and the opposite outer surface of the opposite side wall 14.

[0045] Fig. 8 Figure 1 shows a schematic representation of further stacked molded parts 10 in a sectional view, in which, in addition to the special design of the stacking shoulder 30, a degressive course of the side walls 14 is also shown, which significantly reduces the contact area between the side walls 14 of stacked molded parts 10 and therefore makes it easy to unstack them. Fig. 9 Figure 1 shows an enlarged view of the contact area 22 between a contact surface 32 on the outside of the stacking shoulder 30 of a molded part 10 and a contact surface 34 in the transition between a ring 15 and an edge 17 of the molded parts 10. Fig. 8 and Fig. 10shows an enlarged view of the contact area 20 between the side walls 14 of the molded parts 10 of Fig. 8 .

[0046] The forming of the molded parts 10 described herein can be carried out in a mold for pressing fibrous material, which has a geometry and mold surfaces adapted to the geometry of the molded part 10 to be produced. Despite the optimized design with regard to small contact areas 20, 22 in stacked molded parts 10, the described design of the molded parts 10 does not require a complex tool design, whereby, for example, undercuts 18 can be formed in a mold without slides or other separate movable mold elements.

[0047] The production of three-dimensional shaped bodies 10 can be carried out in several steps, the first of which may involve providing a fiber-containing material. This fiber-containing material can be provided, for example, as pulp or dry fiber material.

[0048] The fibrous material is then introduced into a mold of a molding tool, and the mold is subsequently closed by relative displacement of the mold and a corresponding mold element. This process compresses the fibrous material into three-dimensional molded bodies 10, forming at least a partially degressive profile in one side wall 14 of the molded body 10. Additionally, undercuts 18 can be created simultaneously in edge regions 16.

[0049] Since the undercuts 18 typically exhibit only a slight deflection, the molded parts 10 can be elastically deformed for a short time after compression, similar to the demolding of plastics. The smaller the degree of undercuts 18, the lower the stress on the molded part 10 or the compressed fiber-containing material.

[0050] In further embodiments, the formation of undercuts 18 in edge regions 16 can take place in a subsequent processing step after forming or pressing in the mold. Due to differences in moisture content after pressing, the fibrous material can contract during drying, causing moist areas in the edge region, particularly in the ring 15, to contract into an undercut 18 or to exacerbate the undercut 18. An advantage of such subsequent forming steps is that only small or no undercuts 18 need to be formed during pressing. This facilitates the ejection or removal of formed parts 10 from molds, as only minimal or no deformation of the undercuts 18 occurs during demolding.

[0051] The design of the molded parts 10 can vary depending on the desired shape. Essential for the embodiment disclosed herein is the provision of reduced contact surfaces 20, 22 in stacked molded parts 10.

[0052] The molded parts 10 described herein consist of a fibrous material and can be manufactured, for example, in a so-called wet process. In this process, preforms made of a fibrous material are first prepared and then pressed under thermal influence. The preforms can be prepared by drawing fibers from an aqueous solution (pulp) and forming three-dimensional preforms that essentially already have the shape of the products to be manufactured. Additionally, additives such as starch, chemical additives, wax, etc., can be added to the pulp to influence the properties of the products to be manufactured (e.g., barrier properties) and their processability. The fibers can be, for example, natural fibers such as cellulose fibers or fibers from a fibrous source material (e.g., recycled paper).Since a fibrous pulp containing natural fibers can be used as the starting material for the molded parts 10, the manufactured molded parts 10 can themselves serve as starting material for the production of molded parts 10 or other products after their use, or can be composted, because they can generally be completely decomposed and do not contain any harmful, environmentally hazardous substances.

[0053] The preforms can be further modified and subjected to a pre-pressing step. Subsequently, the preforms are pressed into three-dimensional molded parts 10 in a hot pressing device under pressure and heat.

[0054] Furthermore, the molded parts 10 can be formed from a loose cellulose web (airlaid) or paper.

[0055] In further versions, the molded parts 10 can be laminated or otherwise treated after their manufacture in order to achieve certain properties. Reference symbol list

[0056] 10 Molded part 12 Base 14 Side wall 15 Ring 16 Edge area 17 Edge 18 Undercut 19 Edge surface 20 Contact area 22 Contact area 24 Transition 30 Stacking shoulder 32 Mounting surface 34 Mounting surface α Angle β Angle g Line h Line p Line D Pivot Point H Vertical Axis P Starting Point

Claims

1. Three-dimensional shaped body made of fibrous material, comprising a circumferential side wall (14) that surrounds an interior of the shaped body (10), wherein the side wall (14) has a degressive profile at least section by section from an edge region (16) to a bottom region, wherein a cross-section of the side wall (14) in the bottom region is smaller than a cross-section in the edge region (16).

2. Three-dimensional shaped body according to claim 1, wherein the degressive profile extends from the bottom area to the edge area (16).

3. Three-dimensional shaped body according to claim 1 or 2, wherein the degressive profile along the side wall (14) is divided into segments of equal length for each definable path length, wherein the slope of at least two consecutive path segments is different from each other.

4. Three-dimensional shaped body according to claim 3, wherein the definable path length is defined parallel to the height of the interior or along the surface of the side wall (14).

5. Three-dimensional shaped body according to one of claims 1 to 4, wherein the side wall (14) has a straight and a curved profile.

6. Three-dimensional shaped body according to one of claims 1 to 5, wherein the edge region (16) has an undercut (18).

7. Three-dimensional shaped body according to claim 6, comprising a stacking shoulder (30) in a transition (24) between edge region (16) and side wall (14).

8. Three-dimensional shaped body according to claim 6 or 7, wherein the undercut (18) has an increasing cross-section from an upper section of the edge region (16) to a lower section of the edge region (16) towards the bottom surface.

9. Three-dimensional shaped body according to one of claims 1 to 8, wherein the degressive profile is designed such that when three-dimensional shaped bodies (10) are stacked, there is only line contact between at least two stacked three-dimensional shaped bodies (10) in the area of ​​adjacent side walls (14) of the at least two three-dimensional shaped bodies (10).

10. Method for producing a three-dimensional molded body (10) according to any one of claims 1 to 9, comprising: - providing a fiber-containing material, - introducing the fiber-containing material into a mold of a molding tool; - closing the molding tool by relative displacement of the mold and a corresponding molding element, and - compressing the fiber-containing material to form a three-dimensional molded body (10) with at least a section-wise degressive gradient in a side wall (14) of the molded body (10).

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