EP1932643A2 - Method for manufacturing a glueable substance from fibrous plants and substance plates made thereof - Google Patents

Abstract

The method involves manufacturing the material from fibrous plants, especially hemp or flax or a mixture of these, cutting the plants to lengths of 2 to 30 cm, processing the plants to separate fibers and wooden components and drying the fibrous plants so that the material formed contains stalk pieces containing fibers and wooden components of the plants, whereby fibers and wooden components remain essentially in their natural composition. An independent claim is also included for an intrinsically stable material board of fibrous plants, especially hemp or flax.

Description

The present invention relates to a process for the production of a gluable material for the board industry from fiber plants, a process for the production of intrinsically stable material plates from fiber plants, material plates produced according to the method and a use of the produced material.

For the production of inherently stable material plates usually wood is used. Known examples of these are the so-called chipboards and Oriented Strand Board (OSB) boards. OSB boards have a higher compressive strength compared to chipboard and are therefore also suitable for load-bearing construction purposes.

Instead of wood will be in the EP 0 998 379 B1 presented a straw board, with straw split longitudinally, glued and pressed into plates. The splitting process is considered necessary to achieve the desired strength. An OSB plate made of hemp shives is in the EP 1 181 138 B1 described. The plate is made of hemp shives, ie the woody material of the hemp plant. Shives are obtained after separating the bast fibers. The shives are split to form the composite panels and aligned in parallel. The alignment and splitting of the shives is considered necessary to obtain the desired strength. From this thought goes the EP 0 404 679 B1 further. The building material disclosed therein is made of vegetable fibers, ie in the case of hemp, the material without shives, which is arranged in parallel and grouped in very specific packages. The two last-mentioned documents do not use the entire hemp plant, but only a part thereof, namely shives ( EP 1 181 138 B1 ) or fibers ( EP 0 404 679 B1 ). This means that the hemp plant must be elaborately processed before further processing. Go another way DE 197 56 046 A1 and DE 197 18 352 A1 , Both try hemp processing products, eg. B. building materials or plates to produce by the use of the entire hemp plant. Both, however, reveal a kind of silage process, in the case of DE 197 56 046 A1 by plastification of chopped hemp in agricultural silos and in the case of DE 107 18 352 A1 by pressing into bales and wrapping with foil. It should be noted Furthermore, that a Feldröste- or even a roasting process in these two methods does not take place. In addition, the plant pieces must be defibered before processing.

Despite the numerous attempts to provide a self-stable material plate made of hemp, no such currently available on the market. Experiments have shown that the proposed methods are too labor intensive to produce a low cost material board comparable in price to wood OSB boards. Also, the necessary strength values could not be achieved with the simpler methods proposed.

The invention is in the field of material plates, z. As coarse chipboard, which are also known as OSB plates (English: oriented strand board - plate of aligned chips). These are multi-layer boards, which are made of comparatively long, slim chips (English: strands) made of wood. In contrast to flat pressure plates (chipboard), coarse particleboard have a higher flexural strength, so that coarse particleboard, unlike flat-pressed plates, can also be used for load-bearing purposes.

In order to conserve wood resources, attempts have been made in recent years to replace wood with other naturally renewable raw materials. The prior art has already been cited above. In the WO 98/01611 a fiber product of fibers and shives of flax is described. The fiber product produced is a mat that can be pressed into comparatively stiff products. The fiber product is produced by drying the entire flax plant without seed, crushing it and rubbing it between various rolls, so that fiber bundles and shives are separated from one another. Subsequently, fiber bundles and shives are mixed with synthetic binder fibers to form a mat-like product.

As mentioned above, in the EP 1 181 138 portrayed a composite panel of hemp. This composite panel is made of hemp shives, which are essentially free of bast. For this, the plant is digested before processing to remove the hemp fibers. A disadvantage of these composite panels is the fact that the processing of the hemp plant is comparatively complex to provide the starting material - hemp shives with a defined length and thickness. With the disclosed method it is therefore not possible to provide competitively priced hemp OSB boards to the known wood OSB boards. In addition, there are doubts as to the flexural rigidity of the produced plate and the possibility that this can be used for supporting structures, since hemp shives do not provide the sufficient strength and have proved in practice only as suitable for the production of flat-pressed plates.

The above-mentioned font DE 197 56 046 discloses the production of hemp processing products. For this purpose hemp is chopped immediately after harvesting and stored in silos, whereby a plasticization of hemp chaff is achieved. The ensiled chopped material is then shredded in disc mills, resulting in a comparatively short product. The document does not give any details on plates produced therefrom. Due to the brevity of the shredded pieces produced, these are at best suitable for the production of flat pressed sheets. In addition, in the silage gases that adhere to the plate end product, so that the plates produced therefrom will emit an unpleasant odor.

After harvesting, hemp is left on the field and exposed to the so-called field roast, which dissolves pectins in the hemp stalk. The plants are then pressed into bales and subjected to fiber preparation. As a result, fibers and shives are separated from each other, with the aim is to obtain as shaver-free fibers. If field roasting is not carried out, it is comparatively complicated to separate fibers and shives from one another. For example, a method is disclosed WO 97/45573 ,

Both the traditional method and all other methods have in common that the separation of fibers and shives is relatively complex. For economic reasons, therefore, a coarse chipboard of shives or fibers is unfavorable, even if the bending strength values necessary for coarse particle boards were even reached. To date, no coarse chipboard made of hemp on the market and experiments by the inventors showed that neither shives alone nor fibers alone nor a combination of fibers and shives can be processed into a chipboard that meet the requirements of the standard.

Object of the present invention is therefore to provide a material which is suitable for the production of intrinsically stable material plates and can be produced inexpensively. Furthermore, the material provided without the use of synthetic Binding or supporting fibers to be processed to the material plates. Next, a method is to be provided with which can be produced in a simple manner compared to the prior art, inexpensive intrinsically stable material plates. The intrinsically stable material plates should preferably have such a strength that they can also be used for load-bearing purposes.

The present object is achieved by a method according to claim 1 and a method according to claim 7, and a self-stable material plate according to claim 12 and a use according to claim 13. Advantageous embodiments are subject of the dependent claims.

According to the invention, a method for producing a glueable material for the board industry from fiber plants, especially hemp or flax or a mixture thereof is presented. It involves shortening the fiber plants to a length of 2-30 cm, working up the fiber plants to partially dissolve fibers and woody parts from each other, and drying the fiber plants so that the material formed comprises stems, which fibers and woody parts of the Contain fiber plants. Fibers and woody particles remain essentially in their natural state; they are essentially connected.

The shortening of the fiber plants can take place immediately after the mowing of the fiber plants in the green state or after roasting, in particular field roast.

According to a preferred embodiment, the fiber plants are squeezed, wherein the squeezing of the fiber plants is carried out in particular such that a longitudinal division of the fiber plants, in particular a quartering occurs, wherein the parts produced by the squeezing are still connected to each other via fibers. The crimped fiber plants are preferably worked up by rubbing the stem pieces between two counter-rotating plates or bands or by flinging the stem pieces against a stationary element, in particular a wall or a grid. The shortening and working up of the fiber plants can also be done by pressing the fiber plants into bales and chopping the bales as a whole.

The drying is preferably carried out on a belt dryer, at the same time a cleaning step is included, with which foliage and seed levels are separated.

1. a) Kürzen der Faserpflanzen auf eine Länge von 2-30 cm;
2. b) Aufarbeiten der Faserpflanzen, um Fasern und holzige Anteile teilweise voneinander zu lösen, wobei Fasern und holzige Anteile im Wesentlichen in ihrem natürlichen Verbund bleiben;
3. c) Beleimen des Werkstoffes;
4. d) Aufstreuen des Werkstoffes; und
5. e) Verpressen zu der Werkstoffplatte.

The method according to the invention for producing an inherently stable material plate from fiber plants comprises the following steps:

1. a) shortening the fiber plants to a length of 2-30 cm;
2. b) working up the fiber plants to partially dissolve fibers and woody fractions, leaving fibers and woody fractions essentially in their natural state;
3. c) gluing the material;
4. d) spreading the material; and
5. e) pressing to the material plate.

The fiber plants are preferably roasted and are in particular hemp or flax or a mixture thereof. Alternatively, it is provided that the fiber plants are used in the green state and it is in particular green hemp. Mixtures of roasted and green fiber plants, in particular of green and roasted hemp, are included. As alternative fiber plants in particular kenaf and miscanthus come into question. It is also envisaged that fiber plants and renewable raw materials will be mixed together. In particular, in addition to hemp or flax, at least one further renewable raw material is added, in particular cereal straw, wood, sunflowers, kenaf, miscanthus or nettle.

The scattering can be done without orientation or the fiber plant pieces are aligned in the manner of OSB boards in layers and glued.

The intrinsically stable material plate made from fiber plants produced according to the invention preferably has a bulk density of 80-500 kg / m ³ .

Moreover, a preferred use of the material produced according to the invention, namely for the production of material plates, in particular coarse particle boards, is disclosed. Also molding parts such. B. for the interior of automobiles can be made of it.

In one aspect, a glueable material for the panel industry is made from green hemp. "Green hemp" is understood to mean hemp in a form as it exists when the hemp plant is further processed on the field immediately after harvest without being subjected to the so-called field roast. The expression is independent of the maturation state of the hemp plant. Thus, it does not mean that the hemp is in an immature state, for example, prior to lignification of the stem or before completion of seed maturity, although use of the immature plant in the invention is also possible.

The fiber plant, in particular hemp, is preferably cut to a length of 2-30 cm, preferably 10-15 cm, squeezed and worked up to partially dissolve fibers and woody parts from each other. Next, the green hemp is dried. As a result, a material is produced comprising stem pieces of green hemp. The fiber plant stem pieces contain both fibers and woody portions of the hemp plant, with fibers and woody portions remaining substantially interconnected. In contrast to the usual workup of the fiber plant, especially hemp plant, here no separation of fibers and shives, but the hemp stalk is left in its natural composition and arrangement. By separating the fiber and woody parts of the hemp plant into fibers and shives, the advantageous material properties of the material provided according to the invention are not achieved. The natural bond in the hemp stalk proved to be necessary in experiments to be able to produce load-bearing material plates, in particular coarse particle boards. The method according to the invention achieves precisely this, leaving fibers and woody parts in the natural arrangement, the processing step ensuring that the individual hemp stalk pieces experience a certain degree of crosslinking with each other, since the work-up process makes the fibrous portions to a certain extent be solved by the woody portion. On the other hand, the workup is not so far that a separation of fibers and woody fraction takes place but fibers and woody fractions remain substantially interconnected. Unlike the processing of flax into mat-like products, as described in the WO 98/01611 , the product produced according to the invention does not form a random but single piece, whereby individual pieces of stem stick together.

The individual process steps can be carried out in any desired order and it is also possible to carry out individual process steps in a single step.

At present, in a first aspect of the invention, two embodiments are provided, which will be described below with reference to green hemp. They are also suitable for other green fiber plants and roasted fiber plants. In the first execution, the shortening of the green hemp to a length of 2-30 cm takes place immediately after mowing the hemp plants in the field. This can be done, for example, by using a shredder that cuts both the hemp plant above the ground and cuts the stick. For example, the shredded plant can be blown onto a cart and then removed from the field. Thereafter, the plant pieces are dried and cleaned, in particular, leaf and seed shares are separated as possible. The dried stem pieces are then crimped, for example with rollers. Due to the construction of the hemp stem is done by squeezing usually a quarter of lengthwise. However, the individual parts of the stem are not completely separated after squeezing, but are still stuck together via the fibers. The squeezing process also densifies the plant material. When storing the crushed material so the storage volume can be greatly reduced. Furthermore, the squeezed hemp stalk material for glue and binder is more amenable to processing into chipboard. Finally, the processing of the hemp stalk pieces, with an equalization or loosening is done. The processing can for example be done by counter-rotating plates by the stem pieces are transported on a conveyor belt over which a working in the opposite direction plate is arranged. The Entzerren can also be done by impinging the stem pieces of fixed objects, such as a wall or a grid.

In the alternative version, the hemp plant is mowed by default and possibly shortened to the usual length of 40-60 cm. Immediately after mowing, ie without drying the crop or exposing the field roast, the green hemp is pressed into bales. The whole bale is then promptly fed to a shredder, without the bale would need to be resolved. In the shredder, the green hemp is shortened to a length of 2-30 cm, squeezed and worked up. The intermediate product thus produced is dried and cleaned of leaves and seed residues. Advantage of this embodiment is that mowing and baling can be done with already known machines. Furthermore, the expenditure on equipment and time is reduced by the fact that the process steps of shortening, squeezing and working up take place in a single step.

An advantage of using green fiber plants, especially green hemp or green flax, could be seen in that, unlike the current practice of harvesting hemp, the field has already been cleared immediately after harvest, due to the lack of field roast, and thus reappears to the farmer is available.

The drying step can be done for example by hot air drying on a belt dryer. There, the cleaning can be made, whereby foliage and seed levels are separated.

The material produced by the method according to the invention consists of stem pieces. A separation in shives and fibers, as is done in the usual processing of fiber plants, especially hemp, does not take place. By leaving the hemp plant in the natural arrangement a higher strength is achieved, so that this material for the production of intrinsically stable material plates, in particular coarse particle boards, can be used. The coarse particle board production can be carried out in the usual manner, as it is known for the production of OSB boards made of wood pulp - by layerwise alignment and gluing of the material according to the invention.

In one aspect of the method according to the invention for producing an inherently stable material plate, roasted fiber plants are used. Consequently, fiber plants are used which are exposed after harvest to a roast, also known as rotting. The roasting process causes the pectins in the plant stem to become dissolved or dissolved. Known are the so-called. Tauröste, in which the plant stems are designed in the field and exposed to the weather, and the so-called. Water roasting, the plants are placed in water. In addition, z. As well as the chemical roasting known. Known fiber plants that are often subjected to roasting are flax and hemp. The decisive factor now is that the roasted fiber plants are comminuted without separation into shives and fibers. That is, shives and fibers remain essentially in their natural bond. Only pieces of fiber plants are produced. With the term "im Substantially in their natural bond "is expressed that there is no targeted separation of fiber plants in fibers and shives, but that can be done by the crushing process and, according to a preferred aspect, by the roast itself a certain separation of shives and fibers However, as in the cited documents, in which only targeted fibers or shives or a mixture thereof is used to produce plates, in the method according to the invention, such a separation is currently not performed, but the roasted fiber plants are only crushed The pieces of fiber plants produced are in the order of 10 to 150 mm., After the comminution process, the pieces of fiber plants are glued in. Crucial in connection with this preferred aspect is that, unlike in the documents described above, no longitudinal splitting s plant stem is performed, but the hemp chop is glued without additional splitting operations. As already mentioned, shives and fibers remain essentially in their natural bond, which would be disturbed by a longitudinal splitting of the roasted fiber plant. After gluing the plant pieces they are sprinkled without orientation and pressed to the material board according to the invention. The term "disoriented" in turn, the difference in connection with this aspect of the invention to the prior art is clear. The cited references found it necessary to orient the plant pieces, parallel or even to particular three-dimensional packages to achieve certain strength values. A great advantage of this aspect of the present invention is that such orientation is not necessary. The shredded crop produced, ie the fiber plant pieces produced by the crushing process are scattered and pressed without alignment process. In this context, the invention also differs significantly from the known wood OSB boards, since, as the name implies, the wood chips are oriented, ie aligned.

According to a preferred embodiment of the invention, the comminution of the roasted fiber plants takes place in that the plants are pressed into bales after the roasting process and the bales are chopped as a whole. With this preferred embodiment, the manufacturing process is further simplified. The chopping process produces a relatively inhomogeneous starting material, ie fiber plant pieces. Since the bale is chopped as a whole, some plant pieces are relatively long and others are very short. One would expect dealing with such an inhomogeneous one Starting material can not produce plates with sufficient strength. Surprisingly, however, the opposite is the case. The material plates produced with the inhomogeneous chaff material had excellent stability and strength values in tests.

In the present invention, many prejudices have been overcome in the art. Until the invention it has been assumed that plates with sufficient strength can only be produced if as complete a gluing of the plant material as possible takes place. For this reason, the plant material was split before gluing. Through the splitting process, the tubular stalks were cut so that the binder can surround the plant pieces on all sides. Also hemp has a hollow stem, so that the experts had expected that also with the hemp stalk, the splitting process is essential. However, it was surprisingly found that by using roasted fiber plants and leaving fibers and shives in the natural composite, despite the incomplete gluing, excellent strength values, even better than in the known wood OSB boards, with lower density, could be achieved. Consequently, one skilled in the art had to overcome the prejudice that, due to the incomplete gluing of the pieces in the plate, there would be defects after the pressing operation, which could represent breakages in the use of the plates.

Another prejudice that had to be overcome is the principle that the starting material for the production of intrinsically stable plates with strength values suitable for practical use must be as homogeneous as possible. In the preferred embodiment, in which the plants are pressed into bales and the bales are chopped as a whole, a very inhomogeneous starting material is produced, which can be processed excellently to the material plates according to the invention. As mentioned, excellent strength values are achieved and that at low density.

Finally, for the said inventive use of roasted fiber plants, a third prejudice had to be overcome that the plant pieces need not be oriented, ie not aligned. The experts have until now assumed that in order to achieve high strength values, so that produced material plates can also be used for carrying purposes, an alignment of the plant pieces, eg. B. in the case of OSB boards of wood chips, is essential. A specialist would have in view of the by the Inhomogeneous, entangled starting material assumed that impossible material plates can be produced with sufficient stability. As a result, the inventors had to overcome great prejudices. In view of the problems described, a person skilled in the art would not have attempted to produce material panels from fiber plants by the method mentioned above.

According to a further preferred embodiment, further renewable raw materials are added to the starting material from fiber plant pieces. Examples include cereal straw, wood, sunflowers, kenaf, miscanthus or nettle. The admixing of hemp components, such as fibers and / or shives, is possible.

The produced self-supporting material plate preferably has a bulk density of 80 to 500 kg / m3. By the term "intrinsically stable material plate" is meant plate material that can be used for construction purposes. They are, similar to chipboard and OSB boards, also known as coarse chipboard, for any construction or construction purposes. Also for use as plaster base, such as the known wood wool lightweight panels, or as an acoustic panel for soundproofing the material plates are suitable. It should also be emphasized that the material plates produced have a visually appealing surface. The coloring of the surface can z. B. be set via the pressing temperature. Depending on the pressing temperature, the green or brown tones predominate. By a higher pressing temperature increases the brown coloration, which can even go into the slightly blackish, whereas at lower pressing temperature green tones outweigh. The visually appealing appearance can be used in the use of the plate by the material plates are used as visual elements. The surface can then be ground and painted, glazed, stained, dyed, etc., for example.

According to an aspect of the present invention, there is disclosed a process for producing a glueable material for the plate industry from green hemp, comprising shortening the green hemp to a length of 2-30 cm, squeezing the green hemp, working up the green hemp to partially dissolve fibers and woody fractions, and drying the green hemp such that the formed material comprises green hemp stem pieces containing fibers and woody portions of greenshoe, wherein fibers and woody portions remain substantially interconnected. The shortening of the green hemp takes place immediately after the mowing of the hemp plants. The squeezing of the green hemp takes place in such a way that a Longitudinal division of the hemp, in particular a quartering occurs, wherein the parts produced by the squeezing are still connected to each other via fibers. Further, the crushed green hemp can be worked up by rubbing the stem pieces between two counter-rotating plates or bands or by flinging the stem pieces against a stationary member, in particular a wall or grid. Alternatively, mowed hemp is squeezed without field toast and the bale is chopped using a chopper, so that the steps of shortening to 2-30 cm, squeezing and working up are done in one step. The drying can be done on a belt dryer, at the same time a cleaning step is included, with which foliage and seed levels are separated.

Further disclosed is a process for the production of coarse chipboards from green hemp, comprising the layer-wise alignment and gluing of the material produced according to the invention and coarse chipboard of green hemp, produced by a process according to the invention. Also disclosed is a use of the material according to the invention for the production of coarse particleboard.

1. a) Zerkleinern der gerösteten Faserpflanzen, wobei Schäben und Fasern im Wesentlichen in ihrem natürlichen Verbund bleiben, so dass Faserpflanzenstücke entstehen;
2. b) Beleimen der Faserpflanzenstücke;
3. c) Orientierungsloses Aufstreuen der Faserpflanzenstücke; und
4. d) Verpressen zu der Werkstoffplatte.

It is also a method for producing an intrinsically stable material plate of roasted fiber plants, including the following steps:

1. a) crushing the roasted fiber plants, wherein shives and fibers remain substantially in their natural composite so that fiber plant pieces are formed;
2. b) gluing the fiber plant pieces;
3. c) dislocation of the fiber plant pieces; and
4. d) pressing to the material plate.

The roasted fiber plant is preferably hemp or flax or a mixture of hemp and flax. In addition to the roasted fiber plants, at least one further renewable raw material may be added, in particular cereal straw, wood, sunflowers, kenaf, miscanthus or nettle.

The comminution of the roasted fiber plants is carried out in particular by crunching roasted fiber plants in a roasted state and chopping the bales as a whole.

An intrinsically stable material plate of roasted fiber plants according to the invention has a bulk density of 80-500 kg / m ³ .

Claims (13)

Process for the production of a glueable material for the board industry from fiber plants, in particular hemp or flax or a mixture thereof, comprising cutting the fiber plants to a length of 2-30 cm, working up the fiber plants to partially dissolve fibers and woody particles, and drying fiber plants so that the material formed comprises stem pieces containing fibers and woody portions of the fiber plants, with fibers and woody portions remaining substantially in their natural composition. A method according to claim 1, characterized in that the shortening of the fiber plants takes place immediately after the mowing of the fiber plants in the green state or after roasting, in particular field roast. A method according to claim 1 or 2, characterized in that the fiber plants are squeezed, wherein the squeezing of the fiber plants in particular so that a longitudinal division of the fiber plants, in particular a quartering occurs, wherein the parts produced by the squeezing are still connected to each other via fibers. A method according to claim 3, characterized in that the squeezed fiber plants are worked up by the stem pieces are rubbed between two counter-rotating plates or belts or by the stem pieces against a fixed element, in particular a wall or a grid, are thrown. Method according to one of the preceding claims, wherein the shortening and refurbishing of the fiber plants are carried out by baling the fiber plants and chopping the bales as a whole. Method according to one of the preceding claims, characterized in that the drying takes place on a belt dryer, at the same time a cleaning step is included, with which foliage and seed levels are separated. Method for producing an inherently stable material plate from fiber plants, comprising the following steps: a) shortening the fiber plants to a length of 2-30 cm; b) working up the fiber plants to partially dissolve fibers and woody fractions, leaving fibers and woody fractions essentially in their natural state; c) gluing the material; d) spreading the material; and e) pressing to the material plate. A method according to claim 7, wherein the fibrous plants are roasted and are in particular hemp or flax or a mixture thereof. A method according to claim 7, wherein the fiber plants are used in the green state and in particular are green hemp. Method according to one of the preceding claims, wherein in addition to hemp or flax, at least one further renewable raw material is added, in particular cereal straw, wood, sunflowers, kenaf, miscanthus or nettle. Method according to one of claims 7-10, wherein the scattering takes place without orientation or wherein the fiber plant pieces are aligned and glued in layers. Intrinsically stable fibrous material board made by the method according to any one of claims 7-11 and having a bulk density of 80-500 kg / m 3. Use of a material produced according to any one of claims 1-6 for the production of material plates, in particular coarse particle boards.