Composite material and use of wood usually classified as wood residue The invention relates to a composite material, that is made preferably by gluing, casting or correspondingly as a totally uniform entirety at least of an essen- tially wood based stiffening substance and of an essentially plastic based binding substance. As the stiffening substance wood has been used, that is usually classified as wood residue, such as branches, crowns, logging residue, coppices and/or like in an essentially elongated form.

It is previously known to form composite structures as a combination of a plastic based base material and wood. E. g. plates particularly for building purposes have been manufactured on this principle. On the other hand from application document DE 23 57 817 a structu- ral beam based on composite material is previously known, which discloses a wood-plastic composite structure comprising two or several parts.

In the document above first of all so called sandwich- element structures have been presented, in which outside walls of the elements are plates made of wood- plastic composite, that are combined e. g. by form ties and foam plastics, that has been casted inbetween the same. In the document a solution has been presented as well, in which also the matrix between the outside walls comprises e. g. chopped wood. In the document there has been represented furthermore beam solutions having a closed cross-section and in which side walls are formed of the type of composite plates as descri- bed above, inside of which there has been placed strips of wood that are arranged along the longitu- dinal direction of the beam and that are combined to the beam entirety by casting with a matrix, whereby according to the document e. g. a two-component glue

based on polyurethane is proposed to be used as the matrix. The solutions according to the document above are meant particularly for building purposes, that is why they include always the actual carrying wall structures made of composite structures and a filling situated inside the above, that consists primarily of a matrix. A wider use of the solutions in question than the purpose above does not thus easily come into question. On the other hand the wood substances inside the type of beam structure in question are formed usually from strips, that are produced by sawing wood, so the solution in question as such is not in any way "nature friendly". In addition to that particularly combining wall structures and the filling structure placed inside the same, that have very differing compositions, is a very multiphased and a very deman- ding process, when being carried out e. g. by casting among other things in order to avoid cast pores which, however, usually do not have significant meaning in element structures or beams being used for building purposes.

On the other hand in a Finnish patent 35087 there has been presented furthermore a way to produce formed pieces out of wood, whereby wood substance, such as balks, planks, laths or other pieces of wood corres- ponding the above, is piled freely on the bottom of a mould to form a pile high enough, whereafter as soon as a compression has been carried out all the wood parts of the pile are compressed together in the cross-wise direction forming a tight, uniform log-like piece, whereafter the piece in question is pressed out from the compression space along the grain inside a tightening casing, whereafter the same is being cut up in the cross-wise direction into pieces having desired thickness. In the Patent in question there has been presented furthermore use of a binding substance of a certain type, the meaning of which is to further

gluing of the pieces of wood to each other before the compression phase. What is essential in this solution, is thus a very strong compression of the used wood substance and pushing of the same afterwards inside a thightening casing.

Furthermore in Patent document US 5,543,197 there has been presented a solution, that is to be combined on the principle described above to achieve plates or beams made of bamboo. It is essential in this solution as well, that the result is very woody, so that the binding substance combining the wood substance is not meant or it is not either possible by the same to bring out any kind of significant visual influence for the part of the whole entirety.

The composite material and use of wood usually classi- fied as wood residue according to this invention is aimed to achieve a decisive improvement in the prob- lems described above and thus to raise essentially the prior art. To achieve this aim the composite material according to the invention is primarily characterized in, that the wood substance consists of pieces of wood, that are arranged side by side and essentially parallelly essentially at the same level to form one or several wood substance layers placed one after another/one on top of the other.

As the most crucial advantages of the invention may be mentioned particularly pro-environmentality, whereby during manufacturing of the composite material use of wood being classified usually as wood residue is enabled in a way, that the composite material may be used in most heterogeneous connections starting e. g. from building purposes to other utility purposes as well, such as for manufacturing of pieces of furniture or of most heterogeneous ornamental or utility arti- cles. As an advantageous embodiment the wood sub-

stance, that is being used for manufacturing, is barked and dried, in addition to which as the binding substance advantageously a single or multicomponent thermoplastic, thermoset or a corresponding type of poly-, elastomer or like is being used. In addition to that, it is furthermore possible to use different kinds of filling and colouring substances, e. g. to achieve a desired appearance of the product to be manufactured, that is why the composite material according to the invention has most heterogeneous possibilities for utilization from this point of view as well, when compared e. g. to traditional wood structures. It is possible to make blocks from the composite material according to the invention, because the material in question may be machined by almost all normal machining methods (milling, drilling, sawing, grinding etc.). Also formed pieces, structural beams etc. may be manufactured from the same having finished appearance and dimensions.

Advantageous embodiments of the composite material according to the invention have been presented in the dependent claims related to the composite material.

In following description the invention is illustrated in detail with reference to the appended drawings in which Fig. 1 shows an advantageous structural solution of a block as a perspective view, that is made of the composite material according to the invention and Fig. 2 shows goods, that are made from the composite material according to the invention.

The invention relates to a composite material, that is made preferably by gluing, casting or correspondingly

as a totally uniform entirety at least of an essen- tially wood based stiffening substance 1 and of an essentially plastic based binding substance 2. As a stiffening substance 1 wood has been used, that is usually classified as wood residue 1', such as bran- ches, crowns, logging residue, coppices and/or like in an essentially elongated form. The wood substance 1' consists of pieces of wood 1'a, that are arranged side by side and essentially parallelly s essentially at the same level to form one or several wood substance layers I placed one after another/one on top of the other.

As an advantageous embodiment the wood substance 1'to be used for manufacturing is barked and dried. Corres- pondingly as the binding substance 2 a single or multicomponent thermoplastic, thermoset or a corres- ponding type of poly-, elastomer or like is being used.

Furthermore as an advantageous embodiment with refe- rence particularly to fig. 1, the longitudinal direc- tion p of the pieces of wood 1'a placed in several second wood substance layers I'is arranged to deviate from the longitudinal direction s of the pieces of wood 1'a placed in each first wood substance layer I.

Particularly in the construction shown in fig. 1, the longitudinal direction p of every other wood substance layer I'is arranged essentially perpendicular with respect to the longitudinal direction s of each first wood substance layer I.

Furthermore as an advantageous embodiment, which may not naturally be seen from the presented drawings, an auxiliary substance 3, such as a colour substance has been mixed to the plastic based binding substance 2, to achieve the desired appearance, such as colouring of the composite material. It is naturally possible in

this connection to mix e. g. stones or other kind of natural material or glass, metal etc. to the binding substance 2, also.

In this connection the crucial idea is particularly use of wood usually classified as wood residue, such branches, crowns, logging residue, coppices and/or like in an essentially elongated form in a composite material, that is formed e. g. by casting or correspon- dingly as a totally uniform entirety at least of an essentially wood based stiffening substance 1 and of an essentially plastic based binding substance 2, and, in which the wood substance 1'being used as the stiffening substance consist of pieces of wood 1'a, that are arranged side by side and essentially paral- lelly s essentially at the same level to form one or several wood substance layers I placed one after another/one on top of the other. With reference particularly to fig. 2 the composite material offers most heterogeneous possibilities for utilization, in addition to which the same may be used in addition to e. g. decorating goods of structures or for ornamental goods naturally for e. g. manufacturing of pieces of furniture as well as of usual structural components or beams, plates or the like.

The composite material according to the invention may be produced e. g. by low/high pressure casting into an open or closed mould or accordingly. On the other hand it is also possible to produce the composite material by injection into mould assisted by pressure (injec- tion moulding). Furthermore exhaust of gas or air from the mould may be carried out advantageously by under- pressure. The wood substance may be placed or settled into the mould in very many ways, whereby during installation e. g. different kinds of reinforcement structures based on 2-D or 3-D symmetry may be exploi- ted. As an advantageous embodiment in practice the

volume of the wood substance is aimed to be kept over 80 %.

It is obvious, that the invention is not limited to the embodiments represented or described above, but it may be modified within the basic idea of the invention even to a great extent. It is thus possible to produce solutions, the purpose or appearance of which differ clearly from each other, e. g. by using a binding subs- tance, that have different colours or, that is trans- parent, or correspondingly by changing composing up of the wood substance in the mould. In addition to that it is possible to use fibers chopped longitudinally or e. g. cane etc as the wood substance.