EP4139519B1 - Method for manufacturing a dimensionally stable object from renewable biomass - Google Patents

Description

The invention relates to a method for producing a dimensionally stable object, preferably a container, from renewable biomass.

Methods for producing dimensionally stable objects, in particular containers, as well as dimensionally stable objects from renewable raw materials have been known from the prior art for many years and are used primarily in the field of disposable packaging or disposable items. Such disposable packaging or disposable items are generally used for storing, transporting or packaging food and other consumer goods. There are also methods for producing dimensionally stable objects or dimensionally stable objects from renewable raw materials with a purpose outside of the packaging sector, in particular in the food or consumer goods industry. The dimensionally stable objects can basically replace a large number of objects that are currently made from plastics or other durable materials. Such dimensionally stable objects are in demand by both the end customer and the manufacturing companies, on the one hand in order to use objects on a sustainable basis or to provide products in objects on a sustainable basis.

When it comes to packaging materials in the food industry, the majority of packaging and transport materials used are based on plastics, with the largest proportion being disposable packaging. In recent years there have been increasing efforts to gradually increase the proportion of recycled or biodegradable plastics, although the proportion of plastics made from fossil raw materials continues to dominate. In order to reduce the proportion of fossil raw materials, attempts are being made across industries to use a higher proportion of wood or paper-based raw materials as starting materials for the products to be manufactured as well as for the packaging or transport items. In addition to the predominantly positive environmental factors of items made from renewable biomass, which can be attributed, for example, to a reduction in greenhouse gases and the avoidance of residual waste is, the known dimensionally stable objects based on renewable biomass (or wood or paper-based packaging or transport objects) also have some fundamental disadvantages compared to the known products made of plastic, metals, glass, etc.

The well-known dimensionally stable objects based on renewable biomass (or wood or paper-based packaging or transport objects) are regularly significantly inferior in durability to "conventional" products; In particular, the known dimensionally stable objects based on renewable biomass (or wood or paper-based packaging or transport objects) exhibit disadvantageous behavior in connection with moisture, due, among other things, to the hygroscopic material properties of the raw materials used.

The starting materials for the well-known products based on renewable raw materials are usually fibers obtained from wood. Such fiber cells have different layers and consist mainly of cellulose, hemicelluloses and lignin. Different amounts of the known chemical components cellulose, hemicelluloses and lignin are present in the respective layers. The largest proportions are cellulose (approx. 50 percent) and hemicelluloses (approx. 30 percent). The lignin permeates all layers and has a very low concentration near the lumen, while the majority of the lignin is located in the middle lamella and is difficult to access. In general, the wood fiber is a plant cell that has a similar structure to lignocellulose-containing annual plants. It consists of several primary and secondary walls that enclose the inner cavity, the lumen. The outer ring is called the middle lamella and this primarily serves to connect to the other adjacent cells and consists predominantly of water-insoluble lignin. Separating the individual fiber components naturally involves considerable effort. In the known existing processes from the paper industry, the focus was usually on removing the lignin components. This was intended to achieve a fiber-fiber bond based on so-called hydrogen bonds. However, this type of bond is very sensitive to water, and certain strength properties, such as bending and compressive strength, are strongly negatively influenced.

The well-known dimensionally stable objects based on renewable biomass (or wood or paper-based packaging or transport objects) are generally not suitable for long-term use in a moist environment, which means that a large number of uses are no longer possible. In order to compensate for this natural disadvantage when using renewable biomass, substances are regularly added in one or more of the process steps for producing such dimensionally stable objects, which is intended to optimize the surface or the physical properties of the dimensionally stable object. However, the use of additives in the processing process regularly has the consequence that, on the one hand, the processability is made more difficult, for example by having to carry out further process steps or, on the other hand, that the correspondingly produced, dimensionally stable objects are no longer able to be recycled or composted. Mixing renewable and non-renewable raw materials often leads to the further disadvantage that mixed materials or composite materials (composite materials, composite materials) are created that can no longer be separated from an economic or process engineering point of view and are therefore no longer even available for the circular economy . Such products can therefore only be used in the final step for thermal recycling, which in turn creates greenhouse gases that were originally intended to be avoided.

Further disadvantages of dimensionally stable objects based on renewable biomass (or wood or paper-based packaging or transport objects), in addition to the impaired hygroscopic properties, are the poorer mechanical material properties compared to "conventional" products for comparable purposes. The deteriorated material properties include, among other things, reduced strength properties, elasticity, hardness or brittleness. Many of the known dimensionally stable objects made from renewable biomass are also produced using unsuitable or abbreviated process steps, e.g. B. in order to achieve a "natural" product, essential auxiliary materials or additives are omitted, which on the one hand results in the above-mentioned deteriorated material properties and, on the other hand, end products with inferior aesthetics (surface, cleanliness, discoloration) are produced. If the known processes for producing dimensionally stable objects from renewable biomass do not use additional adhesives, binders or other additives, the resulting products are only available for a very limited range Suitable for intended use and not compatible with “conventional” products, e.g. B. based on plastics, competitive due to the limited material properties.

In the case of the well-known, dimensionally stable objects based on renewable biomass (or wood or paper-based packaging or transport objects), in addition to the technical properties of the products, there are also conflicts of interest and reality regarding the raw materials to be used. In environmental economics this is also referred to as competition of benefits. A well-known example is the plate-tank discussion in the production of biofuels, which can also be transferred to the raw materials to be used for dimensionally stable objects. The basic problem is that raw materials are often used as substitutes for fossil products that are withdrawn from the food industry elsewhere (e.g. wheat, corn or potato starch), which not only increases prices and encourages monocultures in cultivation, but The availability of the corresponding raw materials or food can also be reduced. To counteract this problem, packaging is already known that is made from plant waste that is no longer intended for primary use.

For example, packaging made from plant waste from agriculture is known, which is first shredded by machine. The pulp resulting from the addition of water is shaped and then dewatered using pressure. This creates simple packaging, e.g. E.g. egg cardboard, which generally does not have good properties against external influences such as temperature, humidity, compressive, bending or tensile loads, solar radiation, etc. Increased durability of the packaging produced by this process can be achieved by adding additives such as resins, adhesives, glues, etc., which - as already mentioned above - precludes compostability, recyclability and further use of the raw materials.

The dimensionally stable objects known from the prior art are therefore either not sufficiently durable or have inadequate physical properties if the product properties are based on the carbohydrate building blocks (cellulose, starch, etc.) contained in the natural raw materials; or are no longer considered natural / compostable, dimensionally stable objects if additional binders and additives are added to the manufacturing process. EP0373726A2 discloses a method for producing a cellulosic fiber aggregate having a softening step and a hardening step, wherein in the softening step an aqueous softening agent is allowed to act on a section of cellulosic fiber material at a temperature in the range of 150ºC to 220ºC at a pressure of at least the equilibrium vapor pressure of the softening agent at the working temperature, through which the hemicellulose present in the cellulose fiber material or the lignin present in the cellulose fiber material are at least partially disproportionated and hydrolyzed.

It is therefore an object of the present invention to provide a method for producing a dimensionally stable object, preferably a container, in which the dimensionally stable object has, on the one hand, good and desired material properties, in particular improved strength and water resistance properties compared to the known products made from renewable biomass, and on the other hand needs-based, cost-effective and reliable.

This object is achieved by a method according to claim 1, comprising the following steps: Providing renewable biomass, wherein the renewable biomass contains at least fibers with lignin, in particular cellulose fibers with lignin, hemicelluloses and cellulose, and wherein the renewable biomass from the group of lignocellulose-containing annual plants is selected, comprising at least lignin-containing middle lamellae, cell gussets, primary and secondary walls, comminution of the renewable biomass, adding water to the renewable biomass, pretreatment of the renewable biomass by essentially converting the renewable biomass into biomass fibers by means of a high-temperature steam digestion process providing a steam, wherein the temperature of the steam used is in the range from 150 ° C to 280 ° C, preferably in the range from 175 ° C to 250 ° C, and the digestion time using the steam is in the range from 10 s to 900 s, preferably in the range of 20 s to 300 s, while retaining a majority of the lignin in the fibers, and dissolving and discharging some of the cellulose and hemicelluloses, increasing the relative proportion of the lignin, providing the biomass fibers in a shaping process with an object tool to form a Object molding, thermal treatment of the object molding by converting at least some areas of the lignin contained in the fibers of the biomass fiber materials to the outer surface of the fibers, with the lignin being accessible by tearing open the lignin-containing middle lamellae, the cell gusset, the primary and/or secondary walls, producing an at least partially irreversible connection of the object molding by crosslinking the fibers of the biomass fiber materials with one another using the lignin.

The method according to the invention has surprisingly found that the lignin has positive properties in the production process of a dimensionally stable object in that the phenolic macromolecules of the lignin are included their functional side groups act as binding agents for the dimensionally stable objects to be produced. The lignin does not have to be completely removed from the biomass fibers, but can and should be retained in the fiber structure. A surprising positive effect also occurs when parts of the cellulose and hemicelluloses are removed from the fiber composite of the renewable biomass and removed. In this way, a higher overall proportion of lignin is enriched in the biomass fibers provided in order to apply and implement the surprising properties of the lignin and its cross-linking in conjunction with the remaining fiber components. The lignin, as a 3-dimensional macromolecule, is transferred and enriched to the outer surfaces of the fibers of the biomass fibers during the processing process in order to subsequently contribute to the irreversible cross-linking of the fibers contained in the shaped object during production via its glass transition point (flow point). . As a result, the resulting dimensionally stable objects have positive material properties, such as high strength values, positive water resistance properties, homogeneous material properties, etc. In this way, the dimensionally stable objects produced by the method according to the invention have extensive advantages in terms of material properties compared to the products from the prior art. The natural origin of lignin also means that the dimensionally stable objects can be composted and can be used secondaryally as a raw material for other product groups, for example in the wood-based materials industry. The process steps can preferably be selected depending on the renewable biomass to be used. Depending on the starting material, it is also possible for individual process steps to be omitted or combined. In order to produce a dimensionally stable object, it is particularly important that the lignin is partially "exposed" or partially available during the pretreatment, so that subsequent activation with the crosslinking of the fiber components can be carried out. The method according to the invention is preferably carried out continuously or discontinuously, with particular preference for individual sub-steps, such as the pretreatment or comminution, to be carried out continuously and the shaping process or the thermal treatment to be carried out continuously or discontinuously.

The method according to the invention for producing the dimensionally stable objects requires a low degree of complexity in the process engineering steps, see above that cost-effective operation is possible, which in turn leads to cost-effective end products. Preferably, only one input of water, heat and electrical energy for drive motors is required for the method according to the invention, which means that high costs for process chemicals or other additives, such as fillers or adhesives, are avoided.

During the pretreatment of the renewable biomass by essentially converting the renewable biomass into biomass fiber materials while retaining at least a large part of the lignin in the fibers, preferably at least 50% of the lignin contained in the fibers used from the renewable biomass remains in the biomass fiber material.

For the purposes of the invention, “dimensionally stable object” basically means all objects that can be produced using biomass fiber materials provided. These include, in particular, containers, whereby the containers can be used for a variety of functions. Such dimensionally stable objects or containers are also generally referred to as packaging materials, disposable and reusable packaging, (disposable) tableware, (disposable) bowls, (disposable) plates, (disposable) cups, and “to-go” packaging or the like known. The dimensionally stable objects explicitly include objects that form voids as well as objects with solid materials. Relatively thin-walled, dimensionally stable objects are preferably produced using the method according to the invention, preferably thicknesses in the range from 0.5 mm to 10 mm, although thicker and thinner objects can also be produced using the method according to the invention.

For the purposes of the invention, “renewable biomass” is all biomass that comes from renewable resources. Renewable biomass also includes the addition of non-renewable biomass, such as waste paper or recycled fibers, which contain a maximum of 25 percent by weight. The renewable biomass preferably consists of agricultural residues, which are generally not used primarily.

In the context of the invention, “shredding” the renewable biomass means that the raw material used is shredded in such a way that it can be fed into the subsequent processes. The size of the “shredding” can vary depending on the subsequent process steps. For example, “shredding” is used also used synonymously under the terms cutting, breaking, chopping, grating, scraping, separating, shortening or separating. Shredding regularly leads to segments with a length of 0.5 cm to 15 cm, although longer and shorter shredded segments of renewable biomass are explicitly included in the term.

Alternatively, adding water to the renewable biomass can also be done with water-like solvents or with liquids that predominantly contain water, but have other (natural) components in addition to water.

“Dissolving and removing at least part of the cellulose and hemicelluloses” means in the context of the invention that the proportion of cellulose and hemicelluloses is reduced as part of the pretreatment, or at least is reduced to a greater extent than the proportion of lignin. The removal and discharge can, on the one hand, be controlled and active or, on the other hand, occur as a secondary effect as part of the pretreatment process. However, for the purposes of the invention, it is expedient for at least some of the cellulose and hemicelluloses to be retained, preferably approximately 20% to 70%.

“Creating an at least partially irreversible connection through cross-linking” in the sense of the invention means that not the entire dimensionally stable object has to have an irreversible connection through cross-linking, but is at least cross-linked by means of the lignin in such a way that an irreversible connection is created in some areas, whereby the corresponding positive material properties are generated in the dimensionally stable object.

An expedient embodiment of the invention is characterized in that during the pretreatment the hemicelluloses and the cellulose are at least partially removed from the process by the cellulose and the hemicelluloses being at least partially dissolved out of the renewable biomass, and that the lignin is removed as completely as possible when transferring the renewable biomass is preserved in biomass fiber materials. For the purposes of the invention, “at least partially dissolved out of the renewable biomass” means that at least 10% of the cellulose and/or hemicelluloses are removed from the renewable biomass as part of the pretreatment. The relative proportion of those carried out Cellulose and hemicelluloses are higher than the potential discharged proportion of lignin. “Dissolving” is understood to mean both the intentional and unintentional reduction in the proportion of fiber components that occur or can occur during the pretreatment. A reduction in the proportion of cellulose and hemicelluloses increases the relative proportion of lignin in the intermediate product, the biomass fiber, whereby the surprising positive properties of lignin occur in the course of producing the dimensionally stable objects.

A further expedient embodiment of the invention is characterized in that in the pretreatment, starting from the renewable biomass, 50% to 100%, preferably 60% to 90%, of the lignin, 10% to 90%, preferably 30% to 70%, of the cellulose and 10% to 70%, preferably 30% to 50%, of the hemicelluloses remain in the biomass fibers. When the corresponding cellulose and hemicelluloses are reduced, different relative proportions of lignin arise in the biomass fiber depending on the reduction. As a rule, the dimensionally stable object has improved resistance to external influences such as moisture, bending and pressure loads, etc. with higher relative lignin contents, although in particular the crosslinking is increased with higher lignin contents.

A preferred embodiment is characterized in that the pretreatment of the renewable biomass into biomass fibers takes place by means of mechanical processing, the mechanical processing comprising grinding the renewable biomass. Mechanical processing has the advantage that, on the one hand, a large number of processes and devices are already known from the paper industry that can be used as a basis for mechanical processing and, on the other hand, mechanical processing offers the possibility of changing the fiber structure of the renewable biomass as needed contained fibers. Various devices are conceivable as mechanical processing means, with the fibers preferably being ground using a refiner. In this way, a known technology of mechanical processing can be used to change the fibers according to the corresponding criteria of the method according to the invention. Only mechanical processing is basically known from the paper processing industry, but a different goal is pursued with mechanical processing, as the processes there involve fibrillation of the cellulose for hydrogen bond formation to take place. Exposing or enriching the lignin in the outer areas of the cells and fibers is undesirable. However, the hydrogen bonds mentioned are very sensitive to water and do not form high mechanical strength properties, as is the case with the dimensionally stable objects provided by the method according to the invention.

An advantageous development is characterized in that the mechanical processing is carried out using a refiner with grinding plates, with a plate spacing of the grinding plates of the refiner being selected in the range of 0.05 mm to 5 mm, preferably in the range of 0.1 mm to 0 .5 mm, and wherein a material density of the renewable biomass is selected in the range from 0.5% to 10%, preferably in the range from 1% to 5%. In this way, a reliable option is provided for providing a pretreatment of the renewable biomass to produce biomass fibers. In addition to the plate distance between the grinding plates of the refiner, which can be adjusted as required depending on the renewable raw material to be ground and/or depending on the desired degree of grinding, the selection of the grinding plates can preferably also have an influence on the biomass fiber materials. The grinding plates can preferably have different geometries that can be changed. To produce a more intensive grinding, smaller plate spacings are preferably selected and, to carry out a "gentler" grinding, larger plate spacings can more preferably be selected. Particularly preferably, the pretreatment process can be repeated by means of mechanical processing by the refiner, with the ground biomass produced then being fed back to the mechanical processing at different or the same plate distances. Overall, the renewable biomass is preferably processed by the refiner treatment in such a way that the lignin predominantly (> 50%) remains in the fiber composite or is available for later crosslinking. The material density can be varied depending on the renewable biomass used and/or depending on the fiber processing to be achieved, with a higher material density generally requiring a larger plate spacing between the grinding plates.

According to the invention, the pretreatment of the renewable biomass into biomass fiber materials takes place by means of a high-temperature steam digestion process that provides steam, the temperature of the steam used being in the range from 150 ° C to 280 ° C, preferably in Range from 175 ° C to 250 ° C, and the digestion time using the steam is in the range from 10 s to 900 s, preferably in the range from 20 s to 300 s. This means that the fibers used are already softened, which, among other things the downstream mechanical processing can be carried out with less energy input. Furthermore, the supply of temperature causes the lignin to soften in order to provide (improved) availability of the lignin during the subsequent crosslinking. The duration of the temperature input and the level of the temperature can be varied depending on the renewable biomass used and/or depending on the fiber processing to be achieved, with the longer and higher the temperature input generally being a more intensive pretreatment. The high-temperature steam digestion process can preferably be used for renewable biomass, which as a starting product has a higher stiffness or a plant fiber structure of higher complexity, which is particularly important for perennial plants or more complex grasses such as. B. Bamboo is the case. In particular, the high temperatures during the pretreatment have surprisingly led to an improved availability of the lignin with simultaneous discharge of the cellulose and the hemicelluloses. Due to the high temperatures, i.e. at over 150 ° C to 175 ° C, the lignin present in the middle lamella is particularly accessible, which promotes subsequent crosslinking. The pretreatment is preferably carried out using a steam explosion process, in which a steam treatment is provided for the corresponding renewable biomass from annual plants containing lignocellulose.

A preferred development of the invention is characterized in that during the pretreatment the comminuted lignocellulose-containing annual plants are broken up in such a way that their lignin-containing middle lamellae, the cell gussets and the primary and secondary walls are at least partially broken up, with the lignin being removed as completely as possible when the renewable biomass is transferred is preserved in biomass fiber materials and is exposed for subsequent crosslinking during thermal treatment. In the process steps following the pretreatment, the lignin is used in that its phenolic macromolecule structure is used to form a dimensionally stable object. By exposing the lignin from the middle lamella, it is only possible to use a larger proportion of the lignin, since in conventional processes only a sporadic development of the properties of the lignin is achieved due to an inadequate Availability is given. In the previously known methods, e.g. B. pulp production using the sulfate process, the lignin is usually separated from the cell as completely as possible and removed or remains inside and inaccessible in the middle lamella, e.g. B. TMP or wood pulp processes to prevent contact with other cell components and activation of the lignin.

An advantageous development of the invention is characterized in that the exposed lignin is at least essentially completely designed and set up to produce an irreversible connection of the object molding, whereby the accessibility of the lignin is increased. This leads to an improved and as complete as possible conversion or crosslinking of the lignin during the thermal treatment, which results in particularly advantageous properties when producing the dimensionally stable object.

In an embodiment not according to the claimed invention, the pretreatment of the renewable biomass into biomass fiber materials can be carried out by means of a low-temperature steam digestion process that provides steam, the temperature of the steam used being in the range from 100 ° C to 200 ° C, preferably in the range from 120 ° C to 175 ° C, and the digestion time using the steam is in the range from 50 s to 1,500 s, preferably in the range from 100 s to 900 s. This means that the fibers used are already softened, which means, among other things, the downstream mechanical processing with less Energy input can be carried out. Furthermore, the supply of temperature causes the lignin to soften in order to ensure availability of the lignin during the subsequent crosslinking. The duration of the temperature input and the level of the temperature can be varied depending on the renewable biomass used and/or depending on the fiber processing to be achieved, with the longer and higher the temperature input generally being a more intensive pretreatment. The low-temperature steam digestion process can preferably be used for renewable biomass, which as a starting product has a lower stiffness or a plant fiber structure of low complexity, which is particularly true for annual plants such as. B. grasses or straw is the case.

According to a further preferred embodiment of the invention, the pretreatment of the renewable biomass into biomass fibers takes place by means of a High-yield digestion process, preferably by a carbonate digestion process, the temperature in the high-yield digestion process being in the range from 100 ° C to 215 ° C, preferably in the range from 135 ° C to 175 ° C, and the digestion time being in the range of 15 min to 150 min, preferably in the range from 20 min to 60 min, and a digestion agent with a concentration in the range from 5% to 35% is used, preferably in the range from 10% to 25%, preferably Na ₂ CO is used as the digestion agent ₃ used in solution. The selection and the level of concentration of the digestion agent as well as the duration of the temperature input and the level of the temperature can be varied depending on the renewable biomass used and / or depending on the fiber processing to be achieved, with a more intensive pretreatment usually being formed, depending on The higher the concentration of the digestion agent and the longer and higher the temperature input. The high-yield digestion process can preferably be used for renewable biomass, which as a starting product has a higher stiffness or a plant fiber structure of higher complexity, which is particularly true for perennial plants or more complex grasses such as. B. Bamboo is the case.

A further expedient embodiment of the invention is characterized in that grinding is carried out downstream of the pretreatment, the grinding being carried out by means of a refiner with grinding plates, a plate spacing of the grinding plates of the refiner being selected in the range of 0.05 mm to 5 mm, preferably in the range from 0.1 mm to 0.5 mm, and wherein a consistency of the renewable biomass is selected in the range from 0.5% to 10%, preferably in the range from 1% to 5%. This provides a more extensive opportunity to provide a more in-depth pretreatment of the renewable biomass to produce biomass fibers. In addition to the plate distance between the grinding plates of the refiner, which can be adjusted as required depending on the renewable raw material to be ground and/or depending on the desired degree of grinding, the selection of the grinding plates can preferably also have an influence on the biomass fiber materials. To produce a more intensive grinding, smaller plate spacings are preferably selected and larger plate spacings can be selected to carry out a "gentler" grinding. Preferably, the pretreatment process can be repeated by means of mechanical processing by the refiner, with the ground biomass produced then being fed back to the mechanical processing at different or the same plate distances. Overall will The fiber is preferably treated by the refiner in such a way that the lignin remains predominantly (>50%) in the fiber composite or is available for later crosslinking. The material density can be varied depending on the renewable biomass used and/or depending on the fiber processing to be achieved, with a higher material density generally requiring a larger plate spacing between the grinding plates.

More preferably, at least one further process step for re-sorting and/or shredding the biomass fibers produced is arranged downstream of the pretreatment. Sorting and/or shredding provides a further option for checking and/or homogenizing the raw material produced for the production of dimensionally stable objects. In this way, more uniform and higher quality products can be produced that have a high degree of purity. Contaminants and undesirable particles that may have been absorbed into the material flow during pretreatment can also be identified by sorting and/or shredding and removed from the process.

A preferred development of the invention is characterized in that the shaping process is carried out with the object tool, which is designed and set up as a molding tool and as a pressing tool corresponding to the molding tool, the biomass fiber materials being shaped into the object molding in the molding tool and with the Pressing tool can be pressed to form a pressing tool pressing pressure, the pressing tool pressing pressure being in the range from 0.5 bar to 22 bar, preferably in the range from 1 bar to 8 bar. Execution of the forming process by the article tool increases the forming and uniformity in the process. Designing the object tool as a molding tool with a corresponding pressing tool represents a reliable way to deliver constant qualities in the production of a dimensionally stable object. By developing the pressing tool pressure, dewatering occurs during production, which reduces the subsequent drying time.

An expedient embodiment of the invention is characterized in that the shaping process is selected from one or more of the following processes: injection molding processes, extrusion processes, pressing processes or deep-drawing processes. and blow molding processes. Preferably, the corresponding shaping process is selected depending on the dimensionally stable object to be produced.

An advantageous further development is characterized in that by means of the pretreatment of the renewable biomass into biomass fiber materials in conjunction with the shaping process and/or the thermal treatment, the properties of the dimensionally stable object can be adjusted in such a way that the hardness, the dimensional stability and/or the water resistance, in Depending on the temperature, the pressing pressure, the consistency and/or the degree of grinding, can be varied. In this way, the individual mechanical properties of the dimensionally stable object can be addressed selectively by adjusting the parameters in the process for producing the dimensionally stable object. For example, the nature of the fibers can be varied by a longer grinding time, which results in improved exposure of the lignin, which, among other things, the mechanical properties of the end product can be adjusted. The other parameters can vary depending on the biomass entered and the processes used.

In a further preferred development of the invention, the thermal treatment of the object molding takes place with the formation of a drying press pressure on the object molding, the drying press pressure being in the range from 0.3 bar to 10 bar, preferably in the range from 0.5 bar to 5 bar. In this way, faster drying is achieved. Furthermore, further means and/or process steps can preferably be present upstream or downstream in order to carry out improved drying or to introduce further material properties into the dimensionally stable object, for example a surface treatment.

In a further advantageous embodiment of the invention, the thermal treatment of the object molding takes place without the formation of a drying pressure on the object molding. This reduces the energy costs associated with producing the dimensionally stable object and leads to cost savings and gentler drying.

A further expedient embodiment of the invention is characterized in that the thermal treatment takes place at a temperature in the range from 70 °C to 250 °C, preferably in the range from 130 °C to 200 °C. By using thermal treatment, the drying process can be significantly planned and shortened of the object molding is given, whereby needs-based production can be carried out under known drying parameters. The duration and level of the temperature input can be individually selected and adjusted depending on the renewable biomass used and/or depending on the size or shape of the shaped object.

An advantageous development of the invention is characterized in that the proportion of lignin in the fibers of the renewable biomass is in the range of 5% to 45%, preferably in the range of 15% to 35%. The proportion of lignin depends predominantly on the renewable biomass to be used and can be used and selected accordingly depending on the dimensionally stable object to be produced. For dimensionally stable objects that require high crosslinkability, a renewable biomass with a high lignin content is preferably selected, although for dimensionally stable objects with low required strength properties, renewable biomass with a lower lignin content can also be used.

A further expedient embodiment of the invention is characterized in that no additional organic and/or inorganic adhesives are added during the pretreatment of the renewable biomass, the provision of the biomass fiber materials in the shaping process and during the thermal treatment of the biomass fiber materials. This means that the dimensionally stable objects can be easily composted, which in particular enables simple disposal or recycling. Furthermore, the absence of adhesives still leads to consistent qualitative and mechanical properties with an associated cost saving in the production of dimensionally stable objects, since adhesives represent a high proportion of the costs in production.

An expedient embodiment of the invention is characterized in that no additives are added during the pretreatment of the renewable biomass, the provision of the biomass fiber materials in the shaping process and during the thermal treatment of the biomass fiber materials. This means that the dimensionally stable objects can be easily composted, which in particular enables easy disposal. Furthermore, the absence of additives still leads to consistent qualitative and mechanical properties associated cost savings in the production of dimensionally stable objects, since additives represent a high proportion of the costs in production.

A preferred embodiment is characterized in that the raw materials of the renewable biomass are selected from at least one or a combination of the long-fiber lignocellulose-containing plants, in particular from grasses, grain, straw, bast, leaf, seed and/or seed pod fibers, particularly preferably Miscanthus, hemp, straw, oat husk, flax, sisal and/or bamboo. In a preferred embodiment, a small proportion of the raw materials used can be secondary fibers with a weight proportion of a maximum of 25%.

Fig. 1

eine schematische Darstellung eines Ausführungsbeispiels eines erfindungsgemäßen formstabilen Gegenstandes in einer Ansicht von schräg oben,

Fig. 2

ein Verfahrensschema für ein Ausführungsbeispiel eines erfindungsgemäßen Verfahrens zur Herstellung eines formstabilen Gegenstandes,

Fig. 3

eine vereinfachte schematische Darstellung eines typischen Aufbaus eines Lignin enthaltenen pflanzlichen Zellverbunds und

Fig. 4

eine vereinfachte schematische Darstellung eines typischen Aufbaus eines freigelegten Lignin enthaltenen pflanzlichen Zellverbunds.

Further useful and/or advantageous features and further developments as well as preferred method steps result from the subclaims and the description. Particularly preferred embodiments of the method for producing dimensionally stable objects or the dimensionally stable object are explained in more detail with reference to the accompanying drawings. Shown in the drawings:

Fig. 1

a schematic representation of an exemplary embodiment of a dimensionally stable object according to the invention in a view obliquely from above,

Fig. 2

a process diagram for an exemplary embodiment of a method according to the invention for producing a dimensionally stable object,

Fig. 3

a simplified schematic representation of a typical structure of a lignin-containing plant cell network and

Fig. 4

a simplified schematic representation of a typical structure of an exposed lignin-containing plant cell network.

The method according to the invention for producing a dimensionally stable object and the dimensionally stable object are described in more detail using the aforementioned figures.

The method shown in the drawings for producing a dimensionally stable object based on renewable biomass and the dimensionally stable object made from renewable biomass are shown as an example as a method for producing a container and as a container. The invention relates in the same way to comparable dimensionally stable objects that not only have the function or design of a container.

Fig. 1 shows schematically an embodiment of a dimensionally stable object 10 made from renewable biomass using a container that was produced using the method according to the invention for producing a dimensionally stable object 10. The container has, for example, a base body 11 with a receiving area 12, which is formed by a base 13 and a border 14, which represents a coherent side wall 14.

Fig. 2 shows a process diagram for producing a dimensionally stable object 10 comprising the following steps: (I) providing renewable biomass 15, wherein the renewable biomass 15 contains at least fibers 16 with lignin 17, in particular cellulose fibers with lignin 17, hemicelluloses and cellulose, and wherein the renewable Biomass is selected from the group of lignocellulose-containing annual plants, comprising at least lignin-containing central lamellae, cell gussets, primary and secondary walls, (II) comminution of the renewable biomass 15, (III) adding water to the renewable biomass 15, (IV) pretreatment of the renewable biomass 15 by essentially converting the renewable biomass 15 into biomass fibers 18 while retaining a large part of the lignin 17 in the fibers 16, and while removing and removing at least part of the cellulose and the hemicelluloses, the relative proportion of the lignin 17 being increased, (V) Providing the biomass fiber materials 18 in (VI) a shaping process with an object tool - not shown in detail in the figures - to form an object molding - also not shown in detail in the figures, (VII) thermal treatment of the object molding while converting at least partially the in the lignin 17 contained in the fibers 16 of the biomass fiber materials 18 to the outer surface of the fibers 16, (VIII) producing an at least partially irreversible connection of the object molding by crosslinking the fibers 16 of the biomass fiber materials 18 with one another using the lignin 17.

Preferably, in the pretreatment (IV), the cellulose and the hemicelluloses are at least partially removed from the process by at least partially dissolving the cellulose and the hemicelluloses from the renewable biomass 15, and that the lignin 17 is as completely as possible when transferring the renewable biomass 15 into Biomass fibers are preserved. In the Fig. 4 The structure of the cells is shown schematically and the whereabouts of the lignin 17 when the cell wall or the middle lamella 21 is broken. During this process, the basic structure is usually - deviating from the schematic illustration Fig. 3 and Fig. 4 - The cell is at least partially destroyed, whereby the cellulose and hemicelluloses predominantly contained in the primary and secondary walls are at least partially released. The process is also carried out in an aqueous solution, which promotes the removal of the corresponding cellulose and hemicelluloses.

In a preferred embodiment, in the pretreatment (IV), starting from the renewable biomass, 50% to 100%, preferably 60% to 90%, of the lignin 17, 10% to 90%, preferably 30% to 70%, of the cellulose and 10 remain % to 70%, preferably 30% to 50%, of the hemicelluloses in the biomass fibers 18.

As in the exemplary embodiment Fig. 2 shown, the process step of shredding the biomass 15 can be followed by a further process step (IIa), in which the shredded or used biomass 15 is sorted. Sorting (IIa) means, in particular, that dirt and contaminants are removed from the manufacturing process in this step, as well as checking whether the desired uniform comminution (II) has taken place in the preceding step. If necessary, renewable biomass 15 that is too large or too small can be removed. The aim of comminution (II) and sorting (Ila) is to provide the most homogeneous starting raw material possible for the further process. The process steps (I), (II) and (Ila) can preferably be carried out locally independently of the further process steps for producing the dimensionally stable object 10. Depending on the biomass 15 provided, the shredding step (II) or the sorting step (IIa) can also be omitted if the biomass 15 provided (I) already has a corresponding size or the desired quality requirements for the method according to the invention. The sorting process step (IIa) is in particular carried out by means of at least one sorter and/or by means of at least one hydrocyclone (cleaning). More preferably, a plurality of such devices can be arranged in series or parallel.

Preferably, the pretreatment (IV) of the renewable biomass 15 into biomass fibers 18 takes place by means of (IVa) mechanical processing, the mechanical processing (IVa) comprising grinding the renewable biomass 15. The mechanical processing (IVa) is preferably carried out using a refiner with grinding plates - not shown in detail in the figures - with a plate spacing of the grinding plates of the refiner being selected in the range of 0.05 mm to 5 mm, preferably in the range of 0. 1 mm to 0.5 mm, and wherein a consistency of the renewable biomass is selected in the range of 0.5% to 10%, preferably in the range of 1% to 5%.

In a further preferred embodiment, the pretreatment (IV) of the renewable biomass 15 into biomass fiber materials 18 takes place by means of a high-temperature steam digestion process (Ivb) that provides steam, the temperature of the steam used being in the range from 150 ° C to 280 ° C, preferably in the range of 175 ° C to 250 ° C, and the digestion time using the steam is in the range from 10 s to 900 s, preferably in the range from 20 s to 300 s. The high-temperature steam digestion process (Ivb) is simplified and only schematically as a secondary process step below Pretreatment (IV) in the Fig. 2 shown. In a preferred embodiment, the high-temperature steam digestion process (Ivb) can also be carried out as an independent process step and can be carried out, for example, continuously or in a batch process.

Preferably, during the pretreatment (IV), the comminuted lignocellulose-containing annual plants are broken up in such a way that their lignin-containing central lamellae 21, the cell gussets and the primary and secondary walls are at least partially broken up, with the lignin 17 being preserved as completely as possible when the renewable biomass 15 is converted into biomass fiber materials remains and is exposed for subsequent crosslinking during the thermal treatment (VII). In the Fig. 4 the renewable biomass 15 of a lignocellulose-containing annual plant is shown schematically after its pretreatment (IV), whereby the exposed lignin 17 becomes clear. In the further process steps, the lignin 17 can be used due to its availability. When comparing with the Fig. 3 , where one Exposure of the lignin 17 is not yet given, it becomes clear that a larger contact area is present and an increased activation of the potentially available lignin 17 in the renewable biomass 15 can be provided. Preferably, the exposed lignin 17 is at least essentially completely designed and set up to produce an irreversible connection (VIII) of the object molding, the accessibility of the lignin 17 being increased.

In a further preferred embodiment, the pretreatment (IV) of the renewable biomass 15 into biomass fibers 18 takes place by means of a low-temperature steam digestion process (Ivc) that provides a steam, the temperature of the steam used being in the range from 100 ° C to 200 ° C, preferably in the range of 120 ° C to 175 ° C, and the digestion time using the steam is in the range from 50 s to 1,500 s, preferably in the range from 100 s to 900 s. The low-temperature steam digestion process (Ivc) is simplified and only shown schematically as a secondary process step below Pretreatment (IV) in the Fig. 2 shown. In a further preferred embodiment, the low-temperature steam digestion process (Ivc) can also be carried out as an independent process step and can be carried out, for example, continuously or in a batch process.

In a further preferred embodiment - not shown in the figures - post-processing of the biomass fiber materials 18 can be provided after the pretreatment (IV). For this purpose, further process steps, comparable to steps (II) and (IIa), can be provided. The steps preferably include sorting and/or shredding the biomass fibers 18 in order to provide further quality control of the renewable biomass 15 produced by the pretreatment or mechanical processing. The method steps are carried out in particular by means of at least one sorter and/or at least one hydrocyclone (cleaning).

In the Fig. 2 a further preferred embodiment of the method according to the invention for producing dimensionally stable objects 10 is shown, in which the pretreatment (IV) of the renewable biomass 15 into biomass fiber materials 18 takes place by means of a high-yield digestion process (Ivd), preferably by a carbonate digestion process, the temperature being at the high yield -Digestion process is in the range from 100 °C to 215 °C, preferably in the range from 135 °C to 175 ° C, and wherein the digestion time is in the range of 15 min to 150 min, preferably in the range of 20 min to 60 min, and wherein a digestion agent with a concentration in the range of 5% to 35% is used, preferably in the range of 10 % to 25%, preferably Na ₂ CO ₃ in solution is used as the digestion agent. The high-yield digestion process (Ivd) with the specific exemplary embodiment of the carbonate digestion process is simplified and only shown schematically as a secondary process step under the pretreatment (IV). In a further preferred embodiment, the high-yield digestion process (Ivd) can also be carried out as an independent process step and can be carried out, for example, continuously or in a batch process.

The process steps of the pretreatment (IV) or (IVa) to (IVd) can preferably be carried out downstream of a grinding (IVa'), the grinding being carried out by means of a refiner with grinding plates, with a plate distance between the grinding plates of the refiner in the range of 0 .05 mm to 5 mm is selected, preferably in the range of 0.1 mm to 0.5 mm, and wherein a consistency of the renewable biomass is selected in the range of 0.5% to 10%, preferably in the range of 1% to 5%. In the Fig. 2 Therefore, in the secondary process steps (IVa) to (Ivd), the downstream grinding (IVa') is shown in stylized form in the process diagram.

The process of pretreatment (IV) in the renewable biomass is at the cellular level Fig. 3 and Fig. 4 shown. Fig. 3 shows a simplified representation of a plant cell network 19 with a plurality of plant cells 20. Each of the cells 20 generally has a cell wall (middle lamella) 21 and a cell cavity (lumen) 22. In other words, each of the individual cells 20 can be viewed as part of an individual fiber 16 of the renewable biomass 15 or as a cross-sectional view of a fiber 16, which is connected to further cells 20 via the cell wall 21 or the central lamella to form the plant cell composite 19. In the area of the cell wall 21 or the central lamella, the lignin 17 is regularly arranged in annual plants containing lignocellulose; The main occurrence of lignin is in the middle lamella and the gusset 25, which represents the area where several middle lamellas converge. There are cell wall areas 21 with different levels of lignin, especially in areas where several cell wall areas 21 come together Fig. 3 is a natural cell composite 19 before pretreatment (IV) with the method according to the invention shown. The cells 20 are firmly connected to the lignin 17 and form a rigid cell network 19 that is not soluble in water.

In the Fig. 4 a cell composite 19 is shown during or after the pretreatment (IV), in which the cell composite 19 is at least partially exposed ("torn open"), which is indicated by the stylized cracks 24 in the cell wall 21 area. The pretreatment (IV) converts the renewable biomass 15 into biomass fiber materials 18, with the structure of the cell composite 19 being changed by at least partially exposing the cell walls 21 or the lignin-containing areas of the middle lamella and the gussets 25. The cells 20, that is, the fibers 16, are no longer present as a complex cell composite 19, but the outer surfaces 23 of the exposed cell wall areas 21 were made available through the pretreatment. In this way, the lignin 17 of the cell wall 21 can be made available for the further process, in particular for the shaping process (VI) and the subsequent crosslinking (VIII), thereby enabling the formation of a dimensionally stable object 10 according to the invention. In other words, in the process of exposing the lignin 17 by tearing open the cell composite 19, the transfer of the lignin 17 contained in the fibers 16 of the biomass fiber materials 18 to the outer surface of the fibers 16 can be seen, at least in some areas. The lignin 17 is not necessarily "relocated" to the outer surface 23 of the fibers 16 (locally), but rather the tearing of the cell composite 19 means that the lignin 17 is accessible, which means that subsequent crosslinking (VIII) in the course of the shaping process (VI) and the thermal treatment (VII) to form the dimensionally stable object 10 is made possible.

The process step of the shaping process (VI), which is stylized in the Fig. 2 is shown, is carried out with the object tool, which in a preferred embodiment is designed and set up as a molding tool and as a pressing tool corresponding to the molding tool, the biomass fiber materials 18 being shaped into the object molding in the molding tool and with the pressing tool to form a pressing tool pressure are pressed, the pressing tool pressure being in the range from 0.5 bar to 22 bar, preferably in the range from 1 bar to 8 bar. Preferably, the shaping process (VI) is selected from one or more of the following processes: injection molding processes, extrusion processes, pressing processes or deep-drawing and blow molding processes.

Preferably, by means of the pretreatment (IV) of the renewable biomass 15 into biomass fiber materials 18 in conjunction with the shaping process (VI) and/or the thermal treatment (VII), the properties of the dimensionally stable object 10 can be adjusted in such a way that the hardness, the dimensional stability and/or the water resistance can be varied depending on the temperature, the pressing pressure, the consistency and/or the degree of grinding. In the procedural diagram of the Fig. 2 The individual process steps can be adapted and controlled accordingly. The adjustment of such parameters is preferably carried out on the basis of known process steps, whereby the lignin 17 is made available for the use of crosslinkability in the shaping process (VI) or for the thermal treatment (VII).

The thermal treatment (VII) of the object molding preferably takes place with the formation of a drying pressing pressure on the object molding, the drying pressing pressure being in the range from 0.3 bar to 10 bar, preferably in the range from 0.5 bar to 5 bar. In a further preferred embodiment, the thermal treatment (VII) of the object molding can also take place without the formation of a drying pressure on the object molding. The thermal treatment (VII) preferably takes place at a temperature in the range from 70 °C to 250 °C, preferably in the range from 130 °C to 200 °C.

In the method according to the invention for producing a dimensionally stable object 10, no additional steps are preferably taken during the pretreatment (IV) of the renewable biomass 15, the provision (V) of the biomass fiber materials 18 in the shaping process (VI) and the thermal treatment (VII) of the biomass fiber materials 18 organic and/or inorganic adhesives added. Further preferably, no additives are added during the pretreatment (IV) of the renewable biomass 15, the provision (V) of the biomass fiber materials 18 in the shaping process (VI) and during the thermal treatment (VII) of the biomass fiber materials 18. Particularly preferably, neither organic and/or inorganic adhesives nor additives are added to the entire process for producing the dimensionally stable object 10. The method for producing a dimensionally stable object 10 is preferably carried out only with the raw materials of the renewable biomass 15, with water being included as a solvent.

The raw materials of the renewable biomass 15 are preferably selected from at least one or a combination of the long-fiber lignocellulose-containing plants, in particular from grasses, grain, straw, bast, leaf, seed and/or seed pod fibers, particularly preferably from miscanthus, hemp, straw, Oat husk, flax, sisal and/or bamboo. The raw materials particularly preferably come from agricultural residues that are not available for primary use.

Claims (15)

1. Method for manufacturing a dimensionally stable object (10), preferably a container, comprising the following steps:

   - Providing renewable biomass (15), (I), wherein the renewable biomass (15) contains at least fibres (16) with lignin (17), in particular cellulose fibres with lignin (17), hemicelluloses and cellulose, and wherein the renewable biomass is selected from the group of lignocellulose-containing annual plants, comprising at least lignin-containing central lamellae (21), cell gussets (25), primary and secondary walls,

   - comminuting the renewable biomass (15), (II),

   - adding water (III) to the renewable biomass (15),

   - pre-treatment (IV) the renewable biomass (15) by substantially converting the renewable biomass (15) into biomass fibrous material (18) by means of a high-temperature steam digestion process (IVb) providing a steam, wherein the temperature of the steam used is in the range from 150°C to 280°C, preferably in the range from 175°C to 250°C, and wherein the digestion time by means of the steam is in the range from 10 s to 900 s, preferably in the range from 20 s to 300 s, while retaining a majority of the lignin (17) in the fibres (16), and while dissolving and discharging a part of the cellulose and the hemicelluloses, wherein the relative amount of lignin (17) is increased,

   - providing the biomass fibrous material (18), (V) in a moulding process (VI) with an object mould to form an object moulding,

   - thermally treating (VII) the object moulding by transferring at least partially the lignin (17) contained in the fibres (16) of the biomass fibrous material (18) to the outer surface (23) of the fibres (16), wherein the lignin (17) is made accessible by tearing open the lignin-containing central lamellae, the cell gusset, the primary and/or the secondary walls,

   - creating an at least partially irreversible bond (VIII) of the object moulding by cross-linking the fibres (16) of the biomass fibrous material (18) with one another by means of the lignin (17).
2. Method according to claim 1, characterised in that during the pre-treatment (IV) the cellulose and the hemicelluloses are at least partially discharged from the method by at least partially dissolving the cellulose and the hemicelluloses out of the renewable biomass (15), and in that the lignin (17) is retained as completely as possible when the renewable biomass (15) is converted into biomass fibrous material.
3. Method according to claim 1 or 2, characterised in that in the pre-treatment (IV), starting from the renewable biomass, 50 % to 100 %, preferably 60 % to 90 %, of the lignin, 10 % to 90 %, preferably 30 % to 70 %, of the cellulose and 10 % to 70 %, preferably 30 % to 50 %, of the hemicelluloses remain in the biomass fibrous material (18).
4. Method according to one or more of claims 1 to 3, characterised in that the pre-treatment (IV) of the renewable biomass (15) into biomass fibrous material (18) is carried out by means of a mechanical treatment (IVa), wherein the mechanical treatment (IVa) comprises a grinding of the renewable biomass (15).
5. Method according to claim 4, characterised in that the mechanical treatment (IVa) is carried out by means of a refiner with grinding plates, wherein a plate spacing of the grinding plates of the refiner is selected in the range from 0.05 mm to 5 mm, preferably in the range from 0.1 mm to 0.5 mm, and wherein a stock consistency of the renewable biomass (15) is selected in the range from 0.5 % to 10 %, preferably in the range from 1 % to 5 %.
6. Method according to one or more of claims 1 to 5, characterised in that in the pre-treatment (IV) the comminuted lignocellulose-containing annual plants are broken up in such a way that their lignin-containing central lamellae, the cell gussets and the primary and secondary walls are at least partially broken up, wherein the lignin (17) is retained as completely as possible during the conversion of the renewable biomass (15) into biomass fibrous material and is exposed for subsequent cross-linking in the thermally treating process (VII).
7. Method according to claim 6, characterised in that the exposed lignin (17) is at least substantially completely configured and adapted for creating an irreversible bond (VIII) of the object moulding, wherein the accessibility of the lignin (17) is increased.
8. Method according to claim 1, characterised in that the pre-treatment (IV) of the renewable biomass (15) into biomass fibrous material (18) is performed by means of a high-yield pulping process (IVd), preferably by a carbonate pulping process, wherein the temperature in the high-yield pulping process (IVd) is in the range of 100 °C to 215 °C preferably in the range from 135 °C to 175 °C, and wherein the digestion time is in the range from 15 min to 150 min, preferably in the range from 20 min to 60 min, and wherein a digestion medium with a concentration in the range from 5 % to 35 % is used, preferably in the range from 10 % to 25 %, preferably Na₂CO₃ in solution is used as the digestion medium.
9. Method according to one or more of claims 1 to 8, characterised in that downstream of the pre-treatment (IV) a grinding (IVa') is carried out, wherein the grinding (IVa') is carried out by means of a refiner with grinding plates, wherein a plate spacing of the grinding plates of the refiner is selected in the range from 0.05 mm to 5 mm, preferably in the range from 0.1 mm to 0.5 mm, and wherein a stock consistency of the renewable biomass (15) is selected in the range from 0.5 % to 10 %, preferably in the range from 1 % to 5 %.
10. Method according to one or more of claims 1 to 9, characterised in that the moulding process (IVa) is carried out with the object mould, which is configured and adapted as a moulding tool and as a pressing tool corresponding to the moulding tool, wherein the biomass fibrous materials (18) are formed in the moulding tool as the object moulding and are pressed with the pressing tool to apply a pressing tool pressing pressure, wherein the pressing tool pressing pressure is in the range from 0.5 bar to 22 bar, preferably in the range from 1 bar to 8 bar.
11. Method according to one or more of claims 1 to 10, characterised in that the moulding process (VI) is selected from one or more of the following processes: injection moulding process, extrusion process, compression moulding process or thermoforming and blow moulding process.
12. Method according to one or more of claims 1 to 11, characterised in that, by means of the pre-treatment (IV) of the renewable biomass (15) to biomass fibrous material (18) in conjunction with the moulding process (VI) and/or the thermally treating (VII), the properties of the dimensionally stable object (10) are adjustable in such a way that the hardness, the dimensional stability and/or the water resistance are variable depending on the temperature, the pressing pressure, the stock consistency and/or the degree of grinding.
13. Method according to one or more of claims 1 to 12, characterised in that the thermally treating (VII) of the object moulding is carried out with the formation of a drying pressure on the object moulding, the drying pressure being in the range from 0.3 bar to 10 bar, preferably in the range from 0.5 bar to 5 bar.
14. Method according to one or more of claims 1 to 12, characterised in that the thermally treating (VII) of the object moulding is carried out without the formation of a drying pressure on the object moulding.
15. Method according to one or more of claims 1 to 14, characterised in that the raw materials of the renewable biomass (15) are selected from at least one or a combination of the long-fibre lignocellulose-containing plants, in particular from grasses, grains, straw, bast, leaf, seed and/or seed husk fibres, particularly preferably from miscanthus, hemp, straw, oat husk, flax, sisal and/or bamboo.

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