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

1-19. (canceled)

20. A wood panel, comprising: wood fibers and binder, wherein the wood panel has undulations that are three-dimensional which extend in at least one direction and periodically recur.

21. The wood panel according to claim 20, wherein the undulations are wave-shaped.

22. The wood panel according to claim 20, wherein the wood panel is connected in a superimposed manner to a second wood panel which includes undulations.

23. The wood panel according to claim 22, wherein the undulations of the superimposed wood panels are arranged at an angle to each other.

24. The wood panel according to claim 23, wherein the angle is neither 180? nor 360?.

25. The wood panel according to claim 22, wherein the undulations of the wood panel extend obliquely to a side edge of the second wood panel.

26. The wood panel of claim 22, wherein the undulations of the wood panel have a first shape and the undulations of the second wood panel have a second shape.

27. The wood panel according to claim 20, wherein the wood panel has a thickness and the undulations have a height, and wherein a ratio of the thickness to the height is at least 1:2.

28. The wood panel according to claim 20, wherein at least one surface of the wood panel is connected to a planar element.

29. A method of producing a wood panel, comprising: providing an element including wood fibers; heating the element; deforming the element to form undulations; and cooling the element.

30. The method of claim 29, wherein heating the element includes using hot water vapor.

31. The method of claim 29, wherein the element is heated to a temperature of between about 80? C. to about 400? C.

32. The method of claim 29, wherein deforming the element includes passing the element between a pair of rollers.

33. The method of claim 32, wherein at least one of the pair of rollers is heated such that the heating and the deforming of the element take place simultaneously.

34. The method of claim 29, further comprising bonding the wood panel to a planar material.

35. A corrugated wood element composed of glued wood fibers, comprising: plate-like regions arranged in a zig-zag-shaped fashion, wherein a zig region of the corrugated wood element with an adjoining zag region of the corrugated wood element form a common edge between them in such a way that the corrugated wood element is of zig-zag shaped form, and wherein: (a) the plate-like regions of the corrugated wood element are planar surfaces and the common edge formed between the planar surfaces is a planar surface; or (b) the plate-like regions of the corrugated wood element are surfaces of curved form, and the common edge formed between the curved surfaces is a surface of curved form; or (c) the plate-like regions of the corrugated wood element are surfaces of curved form, and the common edge formed between the curved surfaces is rectilinear; or (d) the plate-like regions of the corrugated wood element are surfaces of curved form, and the common edge formed between the curved surfaces is a surface of planar form.

36. The corrugated wood element according to claim 35, wherein the corrugated wood element has undulations, and wherein the undulations are formed from: corrugated wood elements (a) such that the undulations have, as viewed in longitudinal section, repeating units in the shape of a trapezoid; or corrugated wood elements (b) such that the undulations have, as viewed in longitudinal section, repeating units in the form of a sinusoidal function.

37. The corrugated wooden element according to claim 35, wherein the wood fibers of the corrugated wood element are glued with a glue based on glutin, casein, urea-formaldehyde, phenol-formaldehyde, resorcinol-formaldehyde, polyvinyl acetate, and/or polyurethane.

38. The corrugated wood element according to claim 35, wherein the corrugated wood element has a thickness in the range of 0.2 mm to 2 mm and a height of the corrugated wood element is in the range of 0.8 mm to 8 mm, and wherein the thickness is the smallest distance between two surfaces of a zig or a zag region and the height is the shortest distance between two imaginary planes between which the corrugated wood element can be arranged in such a way that the common edges which are formed between zig regions and zag regions of the corrugated wood element lie within one of the planes.

39. The corrugated wood element according to claim 35, wherein the corrugated wood element is in web form.

Description

[0231] 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.

[0232] 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.

[0233] 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.

[0234] 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.

[0235] 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.

[0236] 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).

[0237] 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.

[0238] 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).

[0239] 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).

[0240] 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).

[0241] 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).

[0242] 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).

[0243] 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).

[0244] 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.

[0245] 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.

[0246] 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.

[0247] 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.

[0248] 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

[0249] 1, 2, 3, 4 Wood elements

[0250] 5, 6, 7, 8, 9, 10, 11, 12 Undulating wood elements

[0251] 1, 2, 3, 4, 6 Edges

[0252] 20, 30 Zig and zag regions

[0253] 70 Connecting point of two edges

[0254] 40 Multilayer composite

[0255] 50 Core layer

[0256] 60, 60 Surface layers