Core layer having wood elements, in particular wood elements having a corrugated structure

Abstract

A core layer suitable for a multilayer composite including at least one surface layer and one core layer, the surface layer arranged to at least partially cover the core layer and be fixedly connected thereto, wherein the core layer has elements composed of wood, which elements have plate-like regions arranged in zig-zag-shaped fashion, wherein a plate-like zig region of an element with an adjoining plate-like zag region of the element form a common edge between them, in such a way that the wood element of zig-zag-shaped form is formed, wherein elements of zig-zag-shaped form are arranged in the core layer such that two such edges of two different elements cross one another at a non-zero angle, and wherein the two elements are fixedly connected to one another at the crossing point. In one embodiment, a wood element of zig-zag-shaped form may be adhesively bonded to a planar wood element.

Claims

1. A core layer, wherein the core layer has elements of zig-zag-shaped form composed of wood, which elements have plate-like regions which are arranged in zig-zag-shaped fashion, wherein a zig region of an element with an adjoining zag region of the element of zig-zag-shaped form form a common edge between them, and wherein elements of zig-zag-shaped form are arranged in the core layer such that two such edges of two elements of zig-zag-shaped form, which edges may be the same as or different from one another, cross one another at a non-zero angle, wherein the two elements are fixedly connected to one another at the crossing point, wherein the wood elements in the core layer have one or more of the following arrangements (a) to (d): (a) the plate-like regions of the wood elements are planar surfaces, and the edge formed between the planar surfaces is a planar surface; (b) the plate-like regions of the wood elements are surfaces of curved form, and the edge formed between the curved surfaces is a surface of curved form; (c) the plate-like regions of the wood elements are surfaces of curved form, and the edge formed between the curved surfaces is rectilinear; (d) the plate-like regions of the wood elements are surfaces of curved form, and the edge formed between the curved surfaces is a surface of planar form; and wherein: (?) the elements composed of wood in the core layer are provided in a random distribution; or (?) the elements composed of wood in the core layer are arranged adjacent to one another and one above the other in random fashion; or (?) the elements composed of wood in the core layer are arranged randomly, and the edges cross one another at different angles; and wherein the direction of the fibers in the wood elements run in the direction of the plate-like regions which are arranged in a zig-zag-shaped fashion and which adjoin one another and the fibers run approximately perpendicular to the common edge of said regions.

2. The core layer as claimed in claim 1, wherein wood elements of zig-zag-shaped form have repeating units of zig and zag regions, in such a way that the wood elements have the form of an undulation, wherein preferably, the common edges formed between the regions run parallel to one another.

3. The core layer as claimed in claim 2, wherein the undulation has at least one positive and one negative half-wave.

4. The core layer as claimed in claim 2, wherein the undulation has at least two positive half-waves but no negative half-waves such that the positive half-waves have a common edge with a first shape that is one of planar, curved, and rectilinear, and the common edge formed between two half-waves is rectilinear.

5. The core layer as claimed in claim 2, wherein the undulation is formed by: wood elements (b), such that the undulation has, as viewed in longitudinal section, repeating units in the form of a sinusoidal function; or wood elements (b) or (c), such that the wood elements have generally punctiform crossing points between a common edge of a first wood element and a common edge of a second wood element.

6. The core layer as claimed in claim 1, wherein the direction at which the fibers in the wood elements run is not parallel to the common edge of said regions.

7. The core layer as claimed in claim 1, wherein the length of the fibers of a wood element of zig-zag-shaped form is at least twice as long as the thickness of a zig or zag region or of the zig-zag-shaped wood element.

8. The core layer as claimed in claim 1, wherein two or more of: the thickness of a zig or zag region lies in the range from 0.2 mm to 2 mm; the length of a common edge lies in the range from 0.5 cm to 10 cm; and the height of a zig or zag region amounts to at most 1/10 of the thickness of the core layer.

9. The core layer as claimed in claim 1, wherein each wood element of zig-zag-shaped form is adhesively bonded to a planar element, in such a way that the element of zig-zag-shaped form and the planar element form one or more cavities between them.

10. The core layer as claimed in claim 1, wherein the core layer has at least one wood element of zig-zag-shaped form, which wood element is adhesively bonded to a planar element such that the element of zig-zag-shaped form and the planar element form one or more cavities between them.

11. The core layer as claimed in claim 1, wherein the core layer has at least one wood element of zig-zag-shaped form, which wood element is adhesively bonded to two planar elements, in such a way that the element of zig-zag-shaped form and the planar elements form multiple cavities between them, wherein the wood element of zig-zag-shaped form is surrounded by the planar elements in sandwich-like fashion.

12. The core layer as claimed in claim 1, wherein the core layer has at least one element which has two wood elements of zig-zag-shaped form which are adhesively bonded to a planar element, in such a way that the elements of zig-zag-shaped form and the planar element form multiple cavities between them, wherein the planar element is surrounded by the two wood elements of zig-zag-shaped form in sandwich-like fashion.

13. The core layer as claimed in claim 1, wherein the wood elements of zig-zag shape are composed exclusively of wood.

14. The core layer as claimed in claim 1, wherein the surface of the wood elements of zig-zag shape is at least partially coated with lignin.

15. A multilayer composite, at least having a surface layer and a core layer, wherein the surface layer is arranged so as to at least partially cover the core layer and be fixedly connected thereto, wherein the core layer is a core layer as defined in claim 1.

16. A multilayer composite, at least having a surface layer and a core layer, wherein the surface layer is arranged so as to at least partially cover the core layer and be fixedly connected thereto, and wherein the multilayer composite is produced by deforming, by compression, at least one layer of the multilayer composite as defined in claim 15.

17. The multilayer composite of claim 15, wherein the surface layer has a material selected from the group consisting of: veneer, wooden board, chipboard, fiberboard, plywood board, plastics board, plasterboard, metal sheet, fiber cement board, and two or more thereof.

18. The core layer as claimed in claim 1, wherein the wood elements in the core layer include two or more of arrangements (a) to (d) such that a common edge of a first wood element is different from a common edge of a second wood element.

19. A core layer, comprising: elements of zig-zag-shaped form composed of wood, which elements have plate-like regions that are arranged in zig-zag-shaped fashion, wherein a zig region of an element with an adjoining zag region of the element of zig-zag-shaped form define a common edge between the zig region and the adjoining zag region, wherein elements of zig-zag-shaped form are arranged in the core layer such that two such common edges of two elements of zig-zag-shaped form, which common edges may be the same as or different from one another, cross one another at a non-zero angle, wherein the two elements are fixedly connected to one another at the crossing point, wherein the wood elements in the core layer have two or more of the following arrangements (a) to (d): (a) the plate-like regions of the wood elements are planar surfaces, and the common edge formed between the planar surfaces is a planar surface; (b) the plate-like regions of the wood elements are surfaces of curved form, and the common edge formed between the curved surfaces is a surface of curved form; (c) the plate-like regions of the wood elements are surfaces of curved form, and the common edge formed between the curved surfaces is rectilinear; (d) the plate-like regions of the wood elements are surfaces of curved form, and the common edge formed between the curved surfaces is a surface of planar form; wherein: (?) the elements composed of wood in the core layer are arranged adjacent to one another and one above the other in random fashion; or (?) the elements composed of wood in the core layer are arranged randomly, and the common edges cross one another at different angles; and wherein the direction of the fibers in the wood elements run in the direction of the plate-like regions which are arranged in a zig-zag-shaped fashion and which adjoin one another and the fibers run at an angle of between approximately 60? and approximately 120? to the common edge of said regions.

20. The core layer of claim 19, wherein the direction at which the fibers in the wood elements run is not parallel to the common edge of said regions.

Description

(1) Exemplary embodiments of the invention are schematically illustrated in the drawings. They will be discussed in more detail below with reference to the figures of the drawings.

(2) FIG. 1 shows a longitudinal section through an embodiment of a wood element 1 of a multilayer composite according to the invention, preferably of a lightweight panel. The wood element has an edge in the form of a planar surface 1, and has a zig region 20 and a zag region 30, wherein said regions are planar surfaces.

(3) FIG. 2 shows a longitudinal section through an embodiment of a wood element 2 of a multilayer composite according to the invention, preferably of a lightweight panel. The wood element has an edge in the form of a convex surface 2, and has a zig region 20 and a zag region 30, which are each curved surfaces.

(4) FIG. 3 shows a longitudinal section of an embodiment of a wood element 3 of a multilayer composite according to the invention, preferably of a lightweight panel. The wood element has a rectilinear edge 3 and has a zig region 20 and a zag region 30, which are each curved surfaces.

(5) FIG. 4 shows a longitudinal section through an embodiment of a wood element 4 of a multilayer composite according to the invention, preferably of a lightweight panel. The wood element has an edge in the form of a planar surface 4, and has a zig region 20 and a zag region 30, which are each curved surfaces.

(6) FIG. 5 shows a longitudinal section through an embodiment of a wood element 5 of a multilayer composite according to the invention, preferably of a lightweight panel. The wood element has repeating units of the wood element 1 of FIG. 1, and is thus of undulating form. The undulation has at least one positive half-wave and also at least one negative half-wave (with respect to the imaginary dashed line).

(7) FIG. 6 shows a longitudinal section through an embodiment of a wood element 6 of a multilayer composite according to the invention, preferably of a lightweight panel. The wood element has repeating units of the wood element 2 of FIG. 2, and is thus of undulating form. The undulation has at least one positive half-wave and also at least one negative half-wave (with respect to the imaginary dashed line). The undulation can be characterized as a sinusoidal undulation.

(8) FIG. 7 shows a longitudinal section through an embodiment of a wood element 7 of a multilayer composite according to the invention, preferably of a lightweight panel. The wood element has repeating units of the wood element 3 of FIG. 3, and is thus of undulating form. The undulation has at least one positive half-wave and also at least one negative half-wave (with respect to the imaginary dashed line).

(9) FIG. 8 shows a longitudinal section through an embodiment of a wood element 8 of a multilayer composite according to the invention, preferably of a lightweight panel. The wood element has repeating units of the wood element 4 of FIG. 4, and is thus of undulating form. The undulation has at least one positive half-wave and also at least one negative half-wave (with respect to the imaginary dashed line).

(10) FIG. 9 shows a longitudinal section through an embodiment of a wood element 9 of a multilayer composite according to the invention, preferably of a lightweight panel. The wood element has repeating units of the wood element 1 of FIG. 1. The undulation has at least two positive half-waves but no negative half-wave (with respect to the imaginary dashed line).

(11) FIG. 10 shows a longitudinal section through an embodiment of a wood element 10 of a multilayer composite according to the invention, preferably of a lightweight panel. The wood element has repeating units of the wood element 2 of FIG. 2 and is thus of undulating form. The undulation has at least two positive half-waves but no negative half-wave (with respect to the imaginary dashed line).

(12) FIG. 11 shows a longitudinal section through an embodiment of a wood element 11 of a multilayer composite according to the invention, preferably of a lightweight panel. The wood element has repeating units of the wood element 3 of FIG. 3 and is thus of undulating form. The undulation has at least two positive half-waves but no negative half-wave (with respect to the imaginary dashed line).

(13) FIG. 12 shows a longitudinal section through an embodiment of a wood element 12 of a multilayer composite according to the invention, preferably of a lightweight panel. The wood element has repeating units of the wood element 4 of FIG. 4 and is thus of undulating form. The undulation has at least two positive half-waves but no negative half-wave (with respect to the imaginary dashed line).

(14) FIG. 13 shows an arrangement of wood elements 6 of undulating form in the core layer according to the invention of a further preferred embodiment of a multilayer composite according to the invention. The arrangement of the wood elements 6 is random. Therefore, the contact surface 70 between mutually adjoining wood elements is in each case a point 70. During the arrangement and subsequent adhesive bonding, the wood elements generally have punctiform connecting points 70 at the edges 6 which cross one another at different angles. During the moderate compression, said connecting points are in turn partially pushed one into the other by upsetting, thus permitting a homogenization of the structure. Depending on the degree of compression, a high to medium cavity fraction remains. This leads to a core layer with a low resulting density, because an orientation of the wood elements 6 along their preferential directions in this regard substantially does not arise. As a result, the core layer is more anisotropic, which implies an anisotropic mechanical characterization of the resulting panel. The structure that is obtained constitutes a random framework, the framework members of which are composed of parallel-fibered wood with high load-bearing capacity. As is generally known in frameworks, the upset, articulated member connections are not weak points, because a framework allows joints. A prerequisite is adequate adhesive bonding of the connecting points in order that longitudinal forces can be accommodated.

(15) FIG. 14 shows an arrangement of wood elements of undulating form from FIG. 13 in the core layer 50 according to the invention of a further preferred embodiment of a multilayer composite 40 according to the invention. The core layer 50 is situated between the surface layers 60, 60, which may be the same as or different from one another, and is adhesively bonded thereto.

(16) Aside from the resulting high compressive and shear strength and stiffness, resulting from the framework structure, of the finished lightweight component, the very low level of swelling of the lightweight panel in terms of thickness in the event of changes in moisture levels, which is achieved owing to the practically negligible swelling of the wood along the fiber direction, must be highlighted. In this way, a panel of said type would be superior to all other wood materials constructed from flat-lying particles or parallel-fibered layers, such as chipboards and fiberboards, plywood or wood core plywoods.

(17) In one embodiment, the wood elements of zig-zag-shaped form may be combined with admixed planar-surfaced elements, that is to say elements of planar-surfaced form. Here, the wood elements of zig-zag-shaped form are preferably adhesively bonded to the planar-surfaced elements. Here, during the adhesive bonding, linear connecting points are formed, in part, between the elements of zig-zag-shaped form and the planar-surfaced elements, giving rise to an increased transverse tensile strength of the lightweight panel.

(18) Wood elements of zig-zag-shaped form, combined with or without planar-surfaced wood elements, may also, in order to form a lightweight core, be mixed with conventional wood material elements such as wood chips or wood fibers. This glued mixture can be compressed to form a lightweight wood material panel, which exhibits further increased homogeneity. Here, it is particularly advantageous that existing technologies, for example from chipboard production, can be used, wherein it is possible to realize panels with a very much lower gross density than in the case of conventional panel production.

LIST OF REFERENCE DESIGNATIONS

(19) 1, 2, 3, 4 Wood elements 5, 6, 7, 8, 9, 10, 11, 12 Undulating wood elements 1, 2, 3, 4, 6 Edges 20, 30 Zig and zag regions 70 Connecting point of two edges 40 Multilayer composite 50 Core layer 60, 60 Surface layers