[0001] The invention relates to a flat wall panel at least substantially made of cellulose
material. The invention also relates to a method for manufacturing said wall panel.
[0002] Such a wall panel is known from German patent No. 2 026 768 (Universal Papertech
corp.). Said patent describes a building that is built up of a great many different
construction elements, such as a concrete floor, roof and side wall panels made of
an intermediate layer of corrugated cardboard sandwiched between two flat outer layers,
as well as cramps and corner elements. In practice, the constructional strength of
the roof and side wall panels appears to be insufficient to give the building sufficient
strength.
[0003] The object of the invention is to improve the wall panel that is known from the aforesaid
German patent publication, in the sense that a wall panel having an optimum constructional
stiffness is provided for use as a construction element of a building, as a wall panel
in, for example, a separation wall, etc. It is noted that the term wall panel is understood
to include an element for use in a wall, a floor, a ceiling, a roof, etc.
[0004] According to the invention, a wall panel of the kind referred to in the introduction
is characterized in that the wall panel is at least substantially made of layers of
paper/cardboard, each layer at least substantially being made up of a corrugated sublayer
and a flat sublayer provided on one side thereof, which layers of paper/cardboard
are interconnected via an adhesive applied to the corrugations of the corrugated sublayers,
wherein the wall panel is impregnated, in particular with a resinous material, and
wherein at least one strengthening layer which is stiffer (i.e. less deformable) than
the layers of paper/cardboard is provided, which strengthening layer is connected
to a layer of paper/cardboard on one side of the wall panel via an adhesive.
[0005] In other words, the whole of various adhered-together layers of paper/cardboard is
connected on at least one flat (outer) are side thereof to the stiffer (i.e. less
deformable) strengthening layer. Experiments have shown that the present construction
leads to an unexpectedly great constructional stiffness of the wall panel, so that
it is possible to subject the wall panel to large forces without the dimensional stability
being affected.
[0006] In a preferred embodiment of a wall panel according to the invention, the wall panel
comprises two strengthening layers, which are connected to a layer of paper/cardboard
on either side of the wall panel via an adhesive. Thus a sandwich construction is
obtained, in which the whole of various adhered-together layers of paper/cardboard
is connected to a stiffer (i.e. less deformable) strengthening layer on both flat
outer sides. The result is an even greater constructional stiffness having a corresponding
dimensional stability.
[0007] It is noted that impregnating the wall panel with, for example, a resinous material
not only has the advantage of providing a greater constructional stiffness, but also
of providing protection against external influences, such as moisture. As a result
of said additional stiffness, fewer layers of corrugated paper/cardboard are in principle
needed in order to give the flat panel the required stiffness. Said impregnation preferably
takes place by means of vapour deposition, spraying or otherwise, said vapour deposition
or spraying taking place in a direction parallel to the direction of the "cell structure"
of the corrugated paper/cardboard that is used. Said impregnation may also be effected
with mechanical means, wherein toothed and/or flat rollers are used for pressing the
impregnating medium into the paper/cardboard.
[0008] In a preferred embodiment of a wall panel according to the invention, the strengthening
layer is made of wood, preferably multiply wood, in particular three-ply wood.
[0009] In another preferred embodiment of a wall panel according to the invention, the wall
panel is at least substantially made of an even number of layers of paper/cardboard.
In combination with the strengthening layer, this provides a plate-shaped material
which is hardly deformable, if at all. Preferably, the wall panel is mirror symmetrical
with respect to a central longitudinal plane of the wall panel so as to increase the
dimension all stability thereof, so that "warping" is prevented at all times.
[0010] As already said before, the invention also relates to a method for manufacturing
a wall panel according to the invention, wherein the wall panel is at least substantially
made of layers of paper/cardboard, each layer at least substantially being made up
of a corrugated sublayer and a flat sublayer provided on one side thereof, which layers
of paper/cardboard are interconnected via an adhesive applied to the corrugations
of the corrugated sublayers, wherein the wall panel is impregnated, in particular
with a resinous material, and wherein at least one strengthening layer which is stiffer
(i.e. less deformable) than the layers of paper/cardboard is provided, which strengthening
layer is connected to a layer of paper/cardboard on one side of the wall panel via
an adhesive.
[0011] It is noted that the term paper is usually used for lighter types of paper; in the
case of a heavier quality, the term cardboard is frequently used. Within the framework
of the invention, the terms paper, cardboard and weight are not intended to be limitative
as regards the type of material to be used.
[0012] The aforesaid resinous material with which the wall panel according to the invention
is impregnated, is preferably an epoxy resin, a polyurethane resin, a polyester resin
or a phenol resin. Fire-resistant and/or fire-retarding agents may be added thereto.
Preferably, the resinous material with which the wall panel according to the invention
is impregnated also functions as an adhesive for adhering two layers of paper/cardboard
together, so that a separate adhesive, such as a glue, is not required. To that end,
sets consisting of a corrugated sublayer and a flat sublayer provided on one side
thereof, which sublayers are already impregnated with the resinous material, can be
placed on top of each other so as to be adhered together (after the resinous material
has dried).
[0013] The invention will now be explained in more detail with reference to figures illustrated
in a drawing of a preferred variant of the invention, in which Fig. 1 is a schematic,
perspective view of the present wall panel, Fig. 2 is a detail view of Fig. 1, and
Fig. 3 is an exploded view of the wall panel of Fig. 1.
[0014] The figure shows a flat wall panel 1 according to the invention in the form of a
"sandwich", in the sense that a core 2 built up of several layers of corrugated cardboard
is connected on either side to a stiffer strengthening layer 3 of multiply wood, in
particular three-ply wood.
[0015] In this case, four layers of corrugated cardboard are provided, which are each built
up of corrugated sublayer 4 and a flat sublayer 5 glued to one side thereof, using
a glue applied to the corrugations 6 of the corrugated sublayer 4. The core 2 is impregnated
with a resinous material. As already said before, the strengthening layers 3 are glued
to both sides of the core 2.
[0016] The wall panel 1 is mirror symmetrical with respect to a central longitudinal plane
7 of the wall panel 1.
[0017] It is noted that the invention is not limited to the embodiment as shown in the figures,
but that it also extends to other variants that fall within the scope of the appended
claims. Thus it will be apparent to those skilled in the art that the wall panel may
exhibit a (slight) curvature, whilst the wall panel may also comprise a curved longitudinal
edge.
1. A flat wall panel at least substantially made of cellulose material, characterized in that the wall panel is at least substantially made of layers of paper/cardboard, each
layer at least substantially being made up of a corrugated sublayer and a flat sublayer
provided on one side thereof, which layers of paper/cardboard are interconnected via
an adhesive applied to the corrugations of the corrugated sublayers, wherein the wall
panel is impregnated, in particular with a resinous material, and wherein at least
one strengthening layer which is stiffer (i.e. less deformable) than the layers of
paper/cardboard is provided, which strengthening layer is connected to a layer of
paper/cardboard on one side of the wall panel via an adhesive.
2. A wall panel according to claim 1, wherein two strengthening layers are provided,
which are connected to a layer of paper/cardboard on either side of the wall panel
via an adhesive.
3. A wall panel according to claim 1 or 2, wherein the strengthening layer(s) is (are)
made of wood.
4. A wall panel according to claim 3, wherein the strengthening layer(s) is (are) made
of multiply, preferably three-ply, wood.
5. A wall panel according to any one of the preceding claims 1-4, wherein the wall panel
is at least substantially made of an even number of layers of paper/cardboard.
6. A wall panel according to claim 5, wherein the wall panel is mirror symmetrical with
respect to a central longitudinal plane of the wall panel.
7. A method for manufacturing a wall panel according to any one of the preceding claims
1-6, characterized in that the wall panel is at least substantially made of layers of paper/cardboard, each
layer at least substantially being made up of a corrugated sublayer and a flat sublayer
provided on one side thereof, which layers of paper/cardboard are interconnected via
an adhesive applied to the corrugations of the corrugated sublayers, wherein the wall
panel is impregnated, in particular with a resinous material, and wherein at least
one strengthening layer which is stiffer (i.e. less deformable) than the layers of
paper/cardboard is provided, which strengthening layer is connected to a layer of
paper/cardboard on one side of the wall panel via an adhesive.