Method for producing a three-dimensional construction element and three-dimensional construction element

Abstract

The invention relates to a method for manufacturing a three-dimensional structural element (1), in particular a soundproofing element, from a substantially flat corrugated cardboard part (2) with a predetermined thickness (dW) and ribs (3) arranged substantially perpendicular to the longitudinal extent of the corrugated cardboard part (2) and channels (4) formed between the ribs (3), as well as such a three-dimensional structural element (1). The following manufacturing steps are provided for the suitable and rapid formation of a three-dimensional structural element: - Application of a liquid hardening agent (5) to the corrugated cardboard part (2); - Placement of the corrugated cardboard part (2) treated with the liquid hardening agent (5) into a mold (6); - Closing of the mold (6) and application of a predetermined pressing pressure (pP) to the corrugated cardboard part (2); - Hardening of the corrugated cardboard part (2) for a predetermined pressing time (tP); - Opening of the mold (6); and - removal of the deformed corrugated cardboard part (2).

Description

[0001] The invention relates to a method for producing a three-dimensional construction element, in particular a soundproofing element, from a substantially flat corrugated cardboard part with a predetermined thickness and webs arranged substantially vertically to the longitudinal extent of the corrugated cardboard part and channels formed between the webs.

[0002] Furthermore, the invention relates to a three-dimensional construction element, in particular a soundproofing element, made from a substantially flat corrugated cardboard part with a predetermined thickness and webs arranged substantially vertically to the longitudinal extent of the corrugated cardboard part and channels formed between the webs.

[0003] The present invention relates to structural elements of any desired three-dimensional shape, which are constructed from essentially flat corrugated cardboard sections. The structural elements can be used, in particular, as soundproofing elements. The term "soundproofing elements" includes both sound absorption elements, which absorb or absorb sound, and sound insulation elements, which are used for the acoustic separation of adjacent rooms. In sound absorption elements, the sound energy is converted into heat in at least one absorption layer arranged behind the corrugated cardboard section as a sound conduction element.

[0004] In addition to being used as soundproofing elements, the three-dimensional structural elements can also be used for other purposes, such as thermal insulation or the interior design of rooms or vehicles. By using corrugated cardboard components with webs and channels arranged essentially vertically to the longitudinal extent of the corrugated cardboard components, the resulting structural elements exhibit high stability while remaining lightweight.

[0005] Manufacturing methods for three-dimensionally shaped corrugated cardboard parts using liquids have been disclosed, for example, in WO 2004 / 022327 A1, US Pat. No. 5,308,678 A, or US Pat. No. 5,643,384 A. The deformation of the corrugated cardboard parts always takes place in the direction of the longitudinal extension of the webs and channels of the corrugated cardboard parts. After deformation, the channels are not essentially oriented perpendicular to the surface of the deformed corrugated cardboard part, but rather in the direction of the surface.

[0006] For example, EP 3 418 461 B1 describes a sound absorption element in which at least one sound-conducting layer made of corrugated cardboard is provided. Such sound absorption elements are typically manufactured in a flat form and arranged on the wall or ceiling of a room for the purpose of sound absorption. To increase design options, the surface of the outermost sound-conducting layer made of corrugated cardboard is machined in a three-dimensional relief and, if necessary, provided with a correspondingly three-dimensional covering. 3D milling is mentioned as a processing method.

[0007] However, machining the surface of the corrugated cardboard part, especially by milling, is associated with a relatively long processing time, resulting in material loss and corresponding contamination during processing. When forming more complex three-dimensional shapes, multi-sided machining of the corrugated cardboard part is required, which further extends the processing time and increases material wear.

[0008] The object of the present invention is therefore to create a manufacturing method for a three-dimensional structural element and a three-dimensional structural element that avoids or at least reduces the aforementioned disadvantages of manufacturing, in particular material wear, but also dirt formation during production and the long production time. Furthermore, a wide range of design options for such three-dimensional structural elements should be provided.

[0009] The object of the invention is achieved by a manufacturing process as mentioned above, which includes the following process steps: Applying a liquid hardener to the corrugated cardboard part; placing the corrugated cardboard part treated with the liquid hardener into a press mold; closing the press mold and applying a predetermined pressing pressure to the corrugated cardboard part; hardening the corrugated cardboard part for a predetermined pressing time; opening the press mold; and removing the deformed corrugated cardboard part.

[0010] The method according to the invention is characterized by simple and rapid processing of the corrugated cardboard part. The deformation takes place essentially in a plane transverse or at an angle to the alignment of the webs and channels of the corrugated cardboard part, or in the case of relief printing, in the direction of the webs and channels of the corrugated cardboard part. To enable deformation without significantly impairing the webs of the corrugated cardboard part, the corrugated cardboard part is softened with a liquid medium before the pressing process. The liquid medium for softening the corrugated cardboard hardens under the influence of air or through chemical processes and, after the pressing period, holds the deformed corrugated cardboard part in its desired shape. After the deformation of the corrugated cardboard part, the alignment of the webs and channels of the corrugated cardboard part is essentially normal to the surface.This allows the three-dimensionally deformed corrugated cardboard part to continue to be optimally used as part of a soundproofing or thermal insulation element, whereby the sound or air can pass through the channels of the corrugated cardboard part into an absorption layer or similar arranged behind it. However, it is also advantageous for other purposes: maintaining the alignment of the channels of the corrugated cardboard part in its deformed position maintains the stability of the deformed corrugated cardboard part. In contrast to processing the corrugated cardboard part using material-removing processes, such as milling, there is no material loss during pressing and therefore no contamination from removed material. Once a press mold has been produced for a desired shape of the deformed corrugated cardboard part, the manufacturing process can be carried out relatively quickly and cost-effectively.The process is therefore particularly suitable for the series production of a large number of identically constructed three-dimensional construction elements.

[0011] Particularly for the formation of a sound absorption element, but also for the formation of thermal insulation elements, it is advantageous if the deformed corrugated cardboard part is bonded on one side to an absorption layer to form the structural element, in particular a soundproofing element. The at least one absorption layer is constructed from suitable materials, preferably biodegradable and / or recyclable materials. For example, sheep's wool, hemp, cellulose, rock wool, etc. are particularly suitable. A cover is preferably arranged on the other side of the corrugated cardboard part. This cover is preferably made of textile material, for example cellulose, jute, sheep's wool, hemp wool, cotton, or even plastic textiles made of polyester or the like.

[0012] According to a further feature of the invention, the deformed corrugated cardboard part is arranged in a frame together with the absorption layer and, if applicable, the cover. The frame, which can be made of wood, for example, provides the structural element with a certain degree of stability and enables simple and rapid installation of the structural element on a wall or ceiling of a room. Optionally, the frame can also have holes through which sound or air can penetrate the absorption layer from the side of the structural element. Furthermore, the holes can reduce the weight of the frame and thus of the three-dimensional structural element.

[0013] The liquid hardener can be applied to the corrugated cardboard part by spraying, brushing, or rolling on one or, preferably, both sides. Depending on the hardener used and the desired deformation of the corrugated cardboard part, certain methods may be more suitable than others. The liquid hardener can be applied manually or automatically using appropriate manipulators or robots. The amount of liquid hardener applied is selected according to the desired deformation of the corrugated cardboard part, allowing the webs to be stretched or compressed without significantly impairing or destroying them. The application of the liquid hardener can also be repeated several times to ensure that all relevant regions of the corrugated cardboard part are coated or absorbed with the hardener.

[0014] As an alternative to applying the liquid hardener by spraying, brushing, or rolling, the liquid hardener can also be applied to the corrugated board part by dipping the corrugated board part into a container containing the liquid hardener. While this method requires a sufficiently large container for the liquid hardener, it allows for faster and more complete impregnation of the corrugated board part with the hardener. Under certain circumstances, the wetting of the entire surface of the corrugated board part can be assisted by mechanical influences, such as vibrations, during the dipping process.

[0015] If a one-component liquid hardener is used, preferably based on water with appropriate additives, curing generally requires the addition of air. Suitable one-component liquids include sodium, potassium, or lithium-based water glass, gypsum milk, cement milk, cellulose-based wallpaper paste, and even acrylic-based liquids.

[0016] To ensure or accelerate the curing of the one-component liquid curing agent with the mold closed, the corrugated cardboard part is cured over the specified pressing time, preferably with the supply of air through appropriate slots or similar devices in the mold. The atmospheric oxygen supplied through appropriately arranged slots or openings or similar devices in the mold enables the curing agent to solidify.

[0017] According to a further feature of the invention when using a one-component liquid as a liquid hardener, the following process steps can be provided after opening the mold: Moving the corrugated cardboard part in the press mold by a specified distance, then closing the press mold and applying a specified pressing pressure; curing the corrugated cardboard part for a further specified pressing time.

[0018] This measure allows the corrugated cardboard part to be moved within the mold, allowing air to flow around those parts that were not exposed to the slots or similar air supply during the previous pressing process, thus also curing them. Moving the corrugated cardboard part within the mold naturally requires a specific geometry with a constant curvature vector. For example, circularly curved shapes or spherical segments can be moved within the mold.

[0019] To accelerate the curing process, the supplied air can be heated, preferably to a temperature between 20 °C and 40 °C. Instead of heating the supplied air, the mold can also be heated to a suitable temperature to accelerate the curing process. This can also be done when using two- or multi-component fluids. Of course, the energy consumption also increases production costs.

[0020] As an alternative to single-component liquids, two- or multi-component liquids can also be used as liquid curing agents. The use of such curing agents also enables curing without the need for air through suitable chemical bonds. Examples of such two- or multi-component liquids include resins and suitable hardeners based on epoxy, acrylic, polyurethane, polyester, etc.

[0021] When using the aforementioned two- or multi-component fluids, the curing of the corrugated board part takes place essentially in the absence of air for the specified pressing time. This simplifies the design of the press mold and can, if necessary, accelerate the curing process. However, if necessary, the curing process of a two- or multi-component fluid can also be carried out with air supply, using a press mold with slots or similar for air supply.

[0022] If the corrugated cardboard part with the applied liquid curing agent is provided with a release agent or release film before the step of inserting the corrugated cardboard part into the mold, this can facilitate the removal of the cured, deformed corrugated cardboard part and prevent contamination of the mold by the liquid curing agent. For example, release films made of polyethylene can be used. As an alternative to the use of release agents or release films, the molds themselves, or at least the surfaces of the molds that face each other, can be made of polyethylene.

[0023] Typically, the mold is closed for a total of between 15 and 60 minutes, including any additional pressing times required, for example, when the corrugated cardboard part is moved within the mold. These times allow for rapid production of the three-dimensional structural elements using this process.

[0024] Preferably, a pressing force of between 0.5 kN and 1000 kN per m² is applied to the corrugated cardboard part when closing the mold. Such forces have proven suitable.

[0025] After the formed corrugated cardboard part has been removed from the mold, granules and / or fibers can be introduced into at least some of the channels. Particularly when used as a soundproofing element, the arrangement of granules and / or fibers in at least some or all of the channels of the corrugated cardboard part can provide improved soundproofing. However, granules or certain fibers made from suitable materials can also bring about improvements in other applications, such as thermal insulation elements. Granules can consist of, for example, activated carbon, wood, bark, cork, salt, sand, plastic, and many more. Fibers that can be used include grass, hemp, cotton, chopped straw, cellulose, leaves, or hay.To prevent the granulate or fibers from escaping from the channels, the cover layers of the corrugated cardboard part are covered with suitable materials, such as textiles (fabrics, scrims or nonwovens) made of natural or synthetic fibers on the front side and cover elements made of wood or similar on the back side.

[0026] The object of the invention is also achieved by an above-mentioned three-dimensional structural element, in particular a soundproofing element, which is manufactured from a substantially flat corrugated cardboard part with a predetermined thickness and webs arranged substantially vertically to the longitudinal extent of the corrugated cardboard part and channels formed between the webs, according to the method described above. Such a structural element can be manufactured relatively easily, quickly, and with no material wear. There are virtually no limits to the design possibilities. For example, spherical structural elements can also be manufactured from several identically manufactured spherical parts. For further advantages of such a structural element, reference is made to the above description of the manufacturing process.

[0027] The thickness of the corrugated cardboard part before forming is preferably between 5 mm and 50 mm. Such corrugated cardboard parts are available relatively inexpensively. If greater thicknesses are required, several corrugated cardboard parts can be formed and arranged one above the other.

[0028] The deformation of the corrugated cardboard part can be carried out in such a way that the thickness of the deformed corrugated cardboard part is essentially constant and preferably essentially corresponds to the thickness of the corrugated cardboard part before deformation. In the case of such a two- or three-dimensional bending of the corrugated cardboard part, no compression of the webs of the corrugated cardboard part occurs.

[0029] However, the deformation can also be carried out in such a way that the thickness of the deformed corrugated cardboard part is different and at least partially smaller than the thickness of the corrugated cardboard part before deformation. In this case, a partial compression of the webs of the corrugated cardboard part or a type of relief printing or embossing of the corrugated cardboard part takes place.

[0030] The invention is explained in more detail with reference to the accompanying figures, in which: Fig. 1 shows an embodiment of a construction element, in particular a soundproofing element, which is made from essentially flat corrugated cardboard parts; Fig. 2 shows an essentially flat corrugated cardboard part before the deformation according to the invention; Fig. 3 shows the corrugated cardboard part after deformation; Fig. 4 shows the steps of deforming the corrugated cardboard part according to the method according to the invention; Fig. 5 shows the steps of deforming the corrugated cardboard part when using a two- or multi-component liquid as a hardening agent; Fig. 6 shows the deformation of the corrugated cardboard part when using a single-component liquid as a hardening agent, with slots for supplying air being provided in the mold; Fig. 7 shows the displacement of the corrugated cardboard part during hardening; Fig. 8 shows an example of a deformed corrugated cardboard part with an essentially constant thickness; Fig. 9 shows an example of a deformed corrugated cardboard part with varying thickness. and Fig. 10 a deformed corrugated cardboard part with granulate in the channels.

[0031] Fig. 1 shows an embodiment of a construction element 1, which is made from essentially flat corrugated cardboard parts 2 with a thickness dw. The corrugated cardboard part 2 has webs 3 essentially vertical to its longitudinal extent and channels 4 formed between the webs 3. The webs 3 can be arranged in a wave-like or honeycomb shape. When the construction element 1 is used as a soundproofing element or insulating element, the corrugated cardboard part 2 is connected on one side to an absorption layer 7. The at least one absorption layer 7 is constructed from suitable materials, preferably biodegradable and / or recyclable materials. For example, sheep's wool, hemp, cellulose, rock wool, etc. are particularly suitable. On the other side of the corrugated cardboard part 2, a cover 8 is preferably arranged.The cover 8 can be hood-shaped and preferably consists of a textile material, for example, cellulose, jute, sheep's wool, hemp wool, cotton, or even plastic textiles made of polyester or the like. The corrugated cardboard part 2 together with the absorption layer 7 and, if applicable, the cover 8 can be arranged in a frame 9. Holes 9' can also be arranged in the frame 9, which can be made of wood, for example. The cover 8 can also be arranged over the frame 9, in particular, stretched or glued.

[0032] In the illustrated embodiment, the structural element 1 consists of a substantially flat corrugated cardboard part 2. The object of the present invention is to create a three-dimensional structural element, wherein the surface of the corrugated cardboard part 2 or the entire corrugated cardboard part 2 can be shaped as desired. Relief-like impressions in the surface of the corrugated cardboard part 2 were previously created, for example, by milling. The present invention is intended to offer a simpler and faster way of producing three-dimensional structural elements 1.

[0033] Fig. 2 shows a substantially flat corrugated cardboard part 2 prior to the deformation according to the invention. The corrugated cardboard part 2 has a substantially constant thickness dw and has webs 3 extending substantially vertically to its longitudinal extent and channels 4 formed between the webs 3. The webs 3 can be arranged in a wave-like or honeycomb shape.

[0034] Fig. 3 shows the corrugated cardboard part 2 after a two-dimensional deformation, i.e. a bending. The thickness d 3D of the deformed corrugated cardboard part 2 essentially corresponds to the thickness dw of the corrugated cardboard part 2 before deformation (see Fig. 2 Depending on the geometry of the deformation, expansion and compression occur within the webs 3 of the corrugated cardboard part 2. To avoid impairment or destruction of the webs 3, which would influence the properties of the deformed corrugated cardboard part 2, it is necessary to soften the corrugated cardboard with a liquid. To ensure that the deformed corrugated cardboard part 2 retains its desired deformed geometry, the liquid for softening the corrugated cardboard must harden. The steps of the inventive manufacturing method of the three-dimensional construction element 1 are described in the next Fig. 4 explained.

[0035] Fig. 4 shows the steps of deforming a substantially planar corrugated cardboard part 2 according to the method according to the invention. For deforming the corrugated cardboard part 2, a press mold 6 consisting of at least two parts designed according to the desired geometry of the deformed corrugated cardboard part 2 is used. First, a liquid hardener 5 is applied to the corrugated cardboard part 2, which can be done by spraying, spreading, or rolling the liquid hardener 5 on one or both sides, or by dipping the corrugated cardboard part 2 into a container 10 containing the liquid hardener 5. The corrugated cardboard part 2 treated or impregnated with the liquid hardener 5 is then introduced into the press mold 6. Before inserting the corrugated cardboard part 2, the press mold 6 can be provided with a release agent 12 or a release film 13.After closing the compression mold 6 and applying a predetermined pressing pressure p P to the corrugated cardboard part 2, the corrugated cardboard part 2 is cured for a predetermined pressing time t P . Depending on the liquid curing agent 5 used, curing takes place with the addition or exclusion of air. After opening the compression mold 6, the deformed corrugated cardboard part 2 has the desired geometry and can be removed from the compression mold 6. The webs 3 and channels 4 of the corrugated cardboard part are oriented essentially perpendicular to the surface of the deformed corrugated cardboard part 2. This makes the deformed corrugated cardboard part 2 particularly suitable for the production of three-dimensional soundproofing elements or insulation elements.

[0036] Fig. 5 shows the steps of deformation of the corrugated cardboard part 2 when using a two- or multi-component liquid as liquid hardener 5 according to Fig. 4 Side view. Curing takes place primarily under the exclusion of air.

[0037] Fig. 6 shows the deformation of the corrugated cardboard part 2 when using a one-component liquid as liquid hardener 5, wherein slots 11 or the like are provided for supplying air in the press mold 6.

[0038] Fig. 7 indicates the displacement of the corrugated cardboard part 2 during curing when using a single-component liquid as the liquid curing agent 5. The corrugated cardboard part 2 is held and cured in its first position in the mold 6. After the mold 6 is opened, the corrugated cardboard part 2 is displaced within the mold 6 by a predetermined distance s. This ensures that even those areas of the corrugated cardboard part 2 are sufficiently cured where, in the previous position, no slots 11 or the like were arranged for supplying air to assist the curing of the liquid curing agent 5 in the mold 6. After the corrugated cardboard part 2 has been displaced by the distance s, which is selected according to the arrangement and dimension of the slots 11 in the pressing mold 6, the pressing mold 6 is closed again and the predetermined pressing pressure p P is applied to the corrugated cardboard part 2 and cured for a further predetermined pressing time t P .These steps of moving the corrugated cardboard part 2 in the pressing mold 6 can be repeated several times if necessary. Moving the corrugated cardboard part 2 in the pressing mold 6 naturally requires a specific geometry of the desired deformed corrugated cardboard part 2 with a constant curvature vector. Arbitrary geometries cannot be moved in the pressing mold 6. For example, circularly curved shapes or spherical segments made of corrugated cardboard can be moved in the pressing mold 6.

[0039] Fig. 8 shows an example of a deformed corrugated cardboard part 2 with a substantially constant thickness d 3D . The deformation of the corrugated cardboard part 2 occurs such that the thickness d 3D of the deformed corrugated cardboard part 2 is substantially constant and preferably substantially corresponds to the thickness d W of the corrugated cardboard part 2 before deformation. In the case of such a two- or three-dimensional bending of the corrugated cardboard part 2, there is no compression of the webs 3 of the corrugated cardboard part 2.

[0040] Fig. 9 shows an example of a deformed corrugated cardboard part 2 with a different thickness d 3D . The thickness d 3D of the deformed corrugated cardboard part 2 is different and in some cases smaller than the thickness d W of the corrugated cardboard part 2 before deformation. In this case, a partial compression of the webs 3 of the corrugated cardboard part 2 or a type of relief printing or embossing of the corrugated cardboard part 2 takes place.

[0041] Finally, Fig. 10a deformed corrugated cardboard part 2 with granules 14 or fibers 15 in the channels 4. After the deformed corrugated cardboard part 2 is removed from the mold 6, the granules 14 and / or the fibers 15 are introduced into at least some of the channels 4 or all of the channels 4 of the corrugated cardboard part 2. Particularly when used as a soundproofing element, the arrangement of the granules 14 and / or fibers 15 can provide improved soundproofing. Granules 14 can consist, for example, of activated carbon, wood, bark, cork, salt, sand, plastic, and many more. Fibers 15 can be used, for example, as grass, hemp, cotton, chopped straw, cellulose, leaves, or hay. In order to prevent the granulate 14 or the fibers 15 from escaping from the channels 4, the cover layers of the corrugated cardboard part 2 are covered with suitable materials, such as textiles on the front and cover elements made of wood or the like on the back (not shown).

Claims

1. A method for producing a three-dimensional construction element (1), in particular a soundproofing element, from a substantially flat corrugated cardboard part (2) with a predetermined thickness (d W ) and webs (3) arranged substantially vertically to the longitudinal extent of the corrugated cardboard part (2) and channels (4) formed between the webs (3), comprising the following steps - applying a liquid hardener (5) to the corrugated cardboard part (2); - placing the corrugated cardboard part (2) treated with the liquid hardener (5) into a press mold (6); - closing the press mold (6) and applying a predetermined pressing pressure (p P ) onto the corrugated cardboard part (2); - hardening the corrugated cardboard part (2) over a predetermined pressing time (t P ) ; - opening the press mold (6); and - removing the deformed corrugated cardboard part (2).

2. Method according to claim 1, characterized in thatthe deformed corrugated cardboard part (2) for forming the construction element (1), in particular the soundproofing element, is connected on one side to an absorption layer (7) and on the other side preferably to a cover (8), and preferably the deformed corrugated cardboard part (2) is arranged together with the absorption layer (7) and possibly the cover (8) in a frame (9).

3. Method according to one of claims 1 to 2, characterized in that the liquid hardener (5) is applied to the corrugated cardboard part (2) by spraying, spreading or rolling on one side or preferably on both sides, or the liquid hardener (5) is applied to the corrugated cardboard part (2) by dipping the corrugated cardboard part (2) into a container (10) with the liquid hardener (5).

4. Method according to one of claims 1 to 3, characterized in thata one-component liquid, preferably based on water with appropriate additives, is used as the liquid hardener (5).

5. Method according to claim 4, characterized in that the curing of the corrugated cardboard part (2) over the specified pressing time (t P ) by supplying air via corresponding slots (11) or the like in the press mould (6).

6. Method according to claim 5, characterized in that after opening the press mould (6), the following steps are carried out: - moving the corrugated cardboard part (2) in the press mould (6) by a predetermined distance (s); - closing the press mould (6) and applying a predetermined pressing pressure (p P ) ; - hardening of the corrugated cardboard part (2) over a further predetermined pressing time (t P' ).

7. Method according to one of claims 4 to 6, characterized in that the supplied air is heated, preferably to a temperature (T) between 20 °C and 40 °C.

8. Method according to one of claims 1 to 3, characterized in that a two- or multi-component liquid is used as the liquid hardener (5) and the hardening of the corrugated cardboard part (2) is carried out over the specified pressing time (t P ) is preferably carried out essentially in the absence of air.

9. Method according to one of claims 1 to 8, characterized in that before the step of inserting the corrugated cardboard part (2) with applied liquid hardener (5) into the press mold (6), the press mold (6) is provided with a release agent (12) or a release film (13).

10. Method according to one of claims 1 to 9, characterized in that after removing the deformed corrugated cardboard part (2) from the press mold (6), a granulate (14) is introduced into at least some channels (4).

11. Method according to one of claims 1 to 10, characterized in that after removing the deformed corrugated cardboard part (2) from the press mold (6), fibers (15) are introduced into at least some channels (4).

12. Three-dimensional construction element (1), in particular soundproofing element, made from a substantially flat corrugated cardboard part (2) with a predetermined thickness (d W ) and webs (3) arranged substantially vertically to the longitudinal extent of the corrugated cardboard part (2) and channels (4) formed between the webs (3), according to a method according to one of claims 1 to 11.

13. Three-dimensional construction element (1) according to claim 12, characterized in that the thickness (d W ) of the corrugated cardboard part (2) before deformation is between 5 mm and 50 mm.

14. Three-dimensional construction element (1) according to claim 12 or 13, characterized in that the thickness (d 3D ) of the deformed corrugated cardboard part (2) is substantially constant and preferably substantially corresponds to the thickness (d W ) of the corrugated cardboard part (2) before deformation.

15. Three-dimensional construction element (1) according to one of claims 12 to 14, characterized in that the thickness (d 3D ) of the deformed corrugated cardboard part (2) is different and preferably at least partially smaller than the thickness (d W ) of the corrugated cardboard part (2) before deformation.

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