Method for producing a material board

Abstract

The invention relates to a method for producing a material board, in particular a wood material board, from a material, the method comprising the following steps: a) providing at least one layer of a material, in particular a material containing wood chips and / or wood fibres, b) providing a press (1, 1') comprising: - an upper pressing device (1A, 1A') and a lower pressing device (1B, 1B') between which a gap (5) is formed for receiving the material, - wherein the upper pressing device (1A, 1A') and / or the lower pressing device (1B, 1B') has hydraulic pressing cylinders (12) which can vary the gap width (8) between the upper pressing device (1A, 1A') and the lower pressing device (1B, 1B') and can transmit pressing forces onto the material, and - wherein the upper pressing device (1A, 1A') and / or the lower pressing device (1B, 1B') has a heating device, in particular a heating plate (14A, 14B), which can at least indirectly transfer heat to the material, c) pressing the material in the gap (5) between the upper pressing device (1A, 1A') and the lower pressing device (1B, 1B'), d) heating the material in the gap (5) between the upper pressing device (1A, 1A') and the lower pressing device (1B, 1B'), - wherein steps c) and d) take place at least in part simultaneously, and wherein the contact pressure (PK) acting on the material during step c) is reduced to a contact pressure (PK) which is in the range of 10 N / cm2 to 150 N / cm2, in particular 30 N / cm2 to 100 N / cm2.

Description

[0001]December 20, 2024 Method for producing a material board The invention relates to a method for producing a material board, in particular a wood-based panel, from a material, comprising the following steps: a) Providing at least one layer of a material, in particular a material containing wood chips and / or wood fibers, b) Providing a press, comprising: an upper pressing device and a lower pressing device, between which a gap is formed to receive the material, wherein the upper pressing device and / or the lower pressing device has hydraulic pressing cylinders that can change the gap width between the upper pressing device and the lower pressing device and can transmit pressing forces to the material, and wherein the upper pressing device and / or the lower pressing device has a heating device, in particular a heating plate,which can at least indirectly transfer heat to the material, c) pressing the material in the gap between the upper pressing device and the lower pressing device, d) heating the material in the gap between the upper pressing device and the lower pressing device, wherein steps c) and d) take place at least partially simultaneously. Material panels, in particular wood-based panels, are known in various designs and are used in a variety of ways – for example, for the construction of furniture. Wood-based panels are produced by joining shredded wood materials,The size and shape of the wood particles determine the properties of the wood-based material and the wood-based panels produced from it. The wood-based materials can be, for example, wood chips (fine chips and / or coarse chips) or wood fibers. Accordingly, the panels produced from these wood-based materials can also be classified as particleboard, coarse particleboard ("OSB board"), medium-density fiberboard ("MDF board"), or high-density fiberboard ("HDF board"). The joining of the shredded wood-based materials usually takes place under the influence of pressure and / or temperature, which is why presses are often used in the manufacturing process. The bonding of the chips or fibers achieved during production is partly based on properties inherent in the chips or fibers (e.g., the properties of lignins,The natural "adhesives" in wood). In addition, the bond between the chips or fibers can be achieved or enhanced by a binder, which is added to the wood-based materials. However, for cost reasons and health protection reasons (e.g., reducing harmful emissions), the general aim is to minimize the use of binders. In addition to the wood-based materials used, the manufacturing processes can also be differentiated based on other criteria, such as the moisture content of the wood-based materials to be processed. Accordingly, a distinction is made between dry and wet processes. In the DIN EN 316 standard, a board produced using the wet process is defined as a "fiberboard with a moisture content of more than 20% at the board forming stage."While a dry-process board is defined as a "fiberboard with a moisture content of less than 20% at the board forming stage." Moisture content (often referred to as "wood moisture content") is a quantity defined as the ratio of the water mass contained in the wood to the dry mass of the wood, expressed as a percentage. It is to be distinguished from the water content of the wood, which represents the ratio of the water mass contained in the wood to the total mass of the (moist) wood, expressed as a percentage. The moisture content is expressed as a percentage (%) ATRO (Absolutely Dry). AC / AC 230725WO December 20, 2024 In practice, the dry process is often carried out with moisture contents of 10% and below, while the wet process is often carried out with moisture contents significantly higher than 20%.For example, at approximately 100% (due to the aforementioned definition of ATRO moisture content, values ​​above 100% are also possible). However, the initial moisture content is significantly reduced in the wet process by mechanically pressing out the moisture in the first step and then evaporating it. Therefore, in wet processes, a screen fabric is arranged on the underside of the chipboard or fiber mat, which facilitates drainage and steam escape, but often leaves an undesirable grid-like imprint on the underside of the board. While binding agents such as glue can often be dispensed with in the wet process, the use of binding agents is common in the dry process. Therefore, the challenge of reducing the use of binding agents, particularly in dry processes, is to provide a method for producing a material board, in particular a wood-based panel,with which boards with good mechanical and optical properties can be produced even with the partial or complete omission of binder. This object is achieved in a method according to the preamble of patent claim 1 in that the contact pressure acting on the material during step c) is reduced to a contact pressure that lies in the range between 10 N / cm² and 150 N / cm², in particular between 30 N / cm² and 100 N / cm². The method is a method for producing a material board, in particular a wood-based board, from a material. The method initially comprises step a), the provision of at least one layer of a material, in particular a material containing wood chips and / or wood fibers. The provision of the (wood) material can be carried out in different ways AC / AC 230725WO December 20, 2024, for example, the (wood) material - if it is a dry,free-flowing material - in one or more layers on a conveyor belt to be fed to a press (common in dry processes). Alternatively to scattering, the material can also be placed on a conveyor belt, for example in the form of a pulp (common in wet processes). The process also comprises step b), the provision of a press. The press can, for example, be a continuously operating press or an intermittently operating press. In the case of an intermittently operating press, presses with one "level" or with several "levels" can be used. The press used in the process initially comprises an upper pressing device and a lower pressing device,between which a gap is formed to accommodate the material. In the gap ("press gap"), the material can be processed into a sheet under the influence of pressure and / or heat. The upper pressing device and / or the lower pressing device has hydraulic pressing cylinders that can change the gap width between the upper pressing device and the lower pressing device (i.e., reduce or increase it) and can transfer pressing forces to the material. In practice, it has proven advantageous to assign the hydraulic pressing cylinders to the upper pressing device. The upper pressing device and / or the lower pressing device also has (at least) one heating device, in particular (at least) one heating plate, which can transfer heat directly or indirectly to the material. Preferably, both the upper pressing device and the lower pressing device have a heating plate,so that the material can be heated from the top and bottom. The method further comprises step c), pressing the material in the gap between the upper pressing device and the lower pressing device, and step d), heating the material in the gap between the upper pressing device and the lower pressing device. Steps c) and d) can partially or completely overlap, i.e., take place at least partially simultaneously. AC / AC 230725WO December 20, 2024 According to the invention, the contact pressure acting on the material during step c) is reduced to a contact pressure that lies in the range between 10 N / cm² and 150 N / cm², in particular between 30 N / cm² and 100 N / cm². It is therefore provided that the contact pressure is not completely eliminated (i.e., reduced to ambient pressure) during step c) - i.e., during the pressing process.but is reduced from a higher pressure level (“working level”) to a lower pressure level (“holding level”) and held there for a while. Pressure relief should therefore take place even before the glue sets. According to one embodiment of the method, the pressure of the press cylinders is reduced during step c) from a working pressure to a holding pressure that lies in the range between 5 bar and 40 bar, in particular between 10 bar and 30 bar. The previously described reduction of the contact pressure acting on the material during the pressing process from a “working level” to a “holding level” can be achieved, for example, by reducing and maintaining the pressure of the press cylinders accordingly. In a further embodiment of the method, the reduced contact pressure and / or the reduced holding pressure is maintained for at least 10 seconds,in particular, is held for at least 20 seconds. By ensuring that the "holding level" lasts sufficiently long, it is ensured that the still quite soft, unstable material plate is "held in shape" and thus stabilized for a sufficient time before the pressing process is terminated and the material plate is released from the opening press. According to a further embodiment of the method, the temperature is reduced from a maximum temperature to a holding temperature that lies in the range between 120°C and 220°C, in particular between 140°C and 180°C. As already described above with regard to pressure, the temperature in the center of the plate should also not be completely reduced (i.e., to ambient temperature) initially,but are lowered from a higher temperature level (“working level”) to a lower temperature level (“holding level”) and maintained there for a while. In a further embodiment of the method, it is provided that the holding temperature is maintained for at least 10 seconds, in particular at least 20 seconds. This ensures that the thermal and / or chemical processes taking place in the material can proceed as completely as possible. According to a further embodiment of the method, it is provided that during step c), the contact pressure acting on the material is reduced, wherein the contact pressure is reduced by at least 50 N / cm², in particular by at least 100 N / cm², preferably by at least 200 N / cm². The pressure reduction should take place “during step c),i.e., during the pressing process. A distinction must be made between the (specific) pressure acting on the material (unit used here: N / cm²) and the hydraulic pressure prevailing in the press cylinders (unit used here: bar). The beginning and end of the pressing process can be defined in relation to both of the aforementioned pressures: The pressing process begins at a point in time at which the specific pressure acting on the material first measurably increases and / or exceeds a value of 1 N / cm². The pressing process ends at a point in time at which the specific pressure acting on the material falls below a value of 1 N / cm² and / or falls below the measurable limit. Alternatively and / or additionally, the pressing process begins at a point in time at which the pressure in the press cylinders first measurably increases and / or exceeds a value of 1 bar. The pressing process ends at a point in timeat which the pressure in the press cylinders falls below 1 bar. Since the pressure reduction occurs during this pressing process, it differs from a (complete) pressure reduction, which typically occurs at the end of or after the end of the pressing process by fully opening the press. The contact pressure acting on the material can be reduced, for example, by reducing the pressure in the press cylinders. Due to the different effective areas, the contact pressure can differ quantitatively from the pressure in the press cylinders by a system-specific factor. The pressure reduction takes place actively and is achieved by opening the press gap.This allows the compressed material to expand slightly again, thus relieving its geometric load. This pressure reduction also differs from the pressure drop that naturally occurs during the pressing of wood-based materials. This familiar pressure drop occurs over time during the pressing process, while the distance of the press gap remains essentially constant. The material plasticizes due to the existing humidity and temperature, so that the counterpressure exerted by the compressed material against the press decreases. In fact, the material's restoring forces still present at the time of the active pressure reduction can be utilized (i.e., especially before the plasticization of the material described above, or before the curing of any binding agents used).to allow the material to breathe and thus enlarge the existing pores between the particles. During the geometric unloading period, the moisture flows out of the material as steam very quickly through the now opened pores. This causes the gas phase (steam-air mixture) to expand. The escape of steam allows any additional water that is still in liquid form to evaporate. Both effects (expansion of the gas phase and evaporation of water) extract energy from the environment, which leads to immediate, rapid cooling inside the material sheet. In addition, drying takes place quickly, so that at the end of the pressing process only a small amount of residual moisture remains in the sheet. With conventional processes, the material evaporates slowly over the entire pressing process and, if necessary, a controlled,Slow release of pressure (and thus slow cooling) takes place to prevent the board, which is still quite soft during this phase, from cracking. However, it has been recognized that rapid steam release is also possible without damaging the board if it occurs at an early stage of the pressing process, i.e., if the pressing process continues during and after the strong steam release (with reduced pressure), and the board is thus still "held in shape" by the press during the steam release. In this way, the board can be "stabilized" to such an extent that significantly less binder can be used, or even that binder can be dispensed with entirely. In principle, pressure and gap width are two variables that can be directly related and mutually influence each other during a pressing process. If one of these two variables changes,The other of these two variables can therefore also change. If, for example, a "pressure reduction" occurs, this can be accompanied by a geometric opening of the press gap (= increase in the gap width); regardless of whether this process is pressure-controlled or distance-controlled. According to one embodiment of the method, during step c), the contact pressure acting on the material is reduced at a rate of at least 100 N / cm²s, in particular at least 200 N / cm²s. According to this embodiment, during step c) – i.e., during the pressing process – the contact pressure acting on the material is reduced rapidly. The minimum pressure reduction rates to be observed here ensure that very rapid cooling and drying take place.which, on the one hand, triggers the previously described processes and, on the other hand, can reduce the process duration and thus increase productivity. According to a further embodiment of the method, during step c), the pressure of the press cylinders is reduced from a working pressure to a holding pressure, wherein the pressure of the press cylinders is reduced by at least 15 bar, in particular by at least 30 bar, preferably by at least 60 bar. As already explained above, the contact pressure acting on the material can be reduced, for example, by correspondingly reducing the pressure prevailing in the press cylinders, whereby the same effects - described above - occur. In a further embodiment, the method provides that during step c), the pressure of the press cylinders is reduced at a rate of at least 10 bar / s,in particular at least 15 bar / s. The aforementioned rapid reduction in the contact pressure acting on the material can be achieved, for example, by a correspondingly rapid reduction in the pressure in the press cylinders. According to a further embodiment of the method, an increase in the gap width occurs during step c), which is in the range between +2% and +20%, in particular between +4% and +15% of the gap width. The gap width can increase during step c) – i.e., during the pressing process – because the contact pressure acting on the material is reduced. The reduced pressure and the increased gap width allow the compressed material to expand somewhat again. Since the increase in the gap width is limited, contact between the material and the two pressing devices – i.e., the upper and lower pressing devices – is maintained even with an increased gap width.so that the pressing process can be continued or does not have to be interrupted. A further embodiment of the method provides that during step c), the temperature in the material is reduced by at least 20°C, in particular at least 30°C, preferably at least 40°C. The temperature present in the material is measured in the center of the plate, i.e., for a plate thickness of 10 mm, it is measured at a "height" of 5 mm. This can be achieved, for example, by a measuring wire inserted into the material for testing purposes. By already in step c) – i.e., already during the pressing process – a significant cooling and drying of the material occurs through the escape of steam, the time required after completion of the pressing process to further reduce the temperature and dry the material is shortened. A further embodiment of the method providesthat during step c) a reduction in the temperature in the material takes place at a rate of at least 10°C / s, in particular at least 20°C / s, preferably at least 30°C / s. According to this embodiment, it is provided that during step c) - i.e. during the pressing process - a rapid reduction in the material temperature is achieved. The minimum cooling rates to be observed here ensure that the process duration can be reduced, which increases productivity. According to one embodiment of the method, it is provided that during step d) the temperature in the material is increased to at least 130°C, in particular at least 150°C, preferably at least 180°C. Due to the unusually high temperatures in the center of the board for the production of wood-based panels - well above 100°C - the natural ingredients of the wood (e.g. lignin, starch,Sugar) can be activated and utilized particularly effectively. Passing through a high-temperature phase can therefore make a significant contribution to improving the mechanical properties of the panels to be produced. A further embodiment of the method provides that during step d), the temperature in the material increases strictly monotonically for at least 20 seconds, in particular for at least 30 seconds. By continuously increasing the temperature over a minimum period during step d) – i.e. during the heating of the material – the thermal and / or chemical processes taking place in the material can proceed without interruption and thus the desired results can be reliably achieved. AC / AC 230725WO December 20, 2024 According to a further embodiment of the method, it is provided that the temperature in the material is 150°C or more for at least 10 seconds, in particular for at least 20 seconds.in particular 180°C or more. By maintaining a minimum duration for the high-temperature phase, it is ensured that the thermal and / or chemical processes taking place in the material can proceed as completely as possible. With regard to the press used in the process, it is proposed that in step b) a cyclically operating press is provided, wherein the upper pressing device is formed by several pressing cylinders and an upper heating plate, and wherein the lower pressing device is formed by a lower heating plate. An cyclically operating press is understood to mean a press in which the material to be processed is not moved continuously, but in cyclically (i.e., is temporarily stationary). The cyclically operating press is first opened in order to insert the material to be pressed into the press. The press is then closed,to press the material. The press is then opened again to remove the newly produced plate from the press. The material for the next plate to be produced can then be inserted into the press, and the aforementioned steps are repeated. Intermittent presses with one "stage" or with multiple "stages" can be used. An intermittent press is shown as an example in Fig. 2 and is described in connection with Fig. 2. With regard to the press used in the method, it is alternatively proposed that in step b) a continuously operating press be provided, wherein the upper pressing device is formed by several press cylinders, an upper heating plate, an upper steel belt, and upper roller bars, wherein the lower pressing device is formed by a lower heating plate, several pressure distribution plates, a lower steel belt, and lower roller bars.wherein the steel belts are mounted so as to rotate around rollers in such a way that the gap for receiving the material is formed between the steel belts, and wherein the roller bars are mounted so as to rotate around rollers AC / AC 230725WO December 20, 2024 in such a way that they are arranged between the steel belts and the heating plates and enable relative movement between the steel belts and the heating plates. A continuously operating press is understood to mean a press in which the material to be processed is continuously moved, i.e., does not rest during any process step - not even during pressing of the material. A continuously operating press is shown as an example in Fig. 1 and is described in connection with Fig. 1. According to a further embodiment of the method, it is provided that in step a) the wood-based material is provided in multi-layer form, in particular in 3-layer, 5-layer, or 7-layer form,in particular with at least one middle layer, at least one lower cover layer, and at least one upper cover layer. The different layers or plies of the material can differ, for example, in their ingredients (chips, fibers), the size of the ingredients (small chips, large chips), the density, and / or the moisture content. In this way, the mechanical properties of the panel to be produced can be optimized. For example, it can be provided that the middle layer (less relevant for flexural strength) is less dense and thus "lighter" through the use of coarser chips than the cover layers (more relevant for flexural strength), which are denser through the use of finer chips. It can also be provided that the moisture content of the cover layers (i.e., the surfaces) is greater than that of the middle layer. According to a further embodiment of the method,that in step a), a wood-based material with a moisture content in the range between 2% ATRO and 40% ATRO, in particular between 5% ATRO and 30% ATRO, particularly preferably between 10% ATRO and 25% ATRO is provided. Optimum results have been achieved with a moisture content within the stated limits. AC / AC 230725WO December 20, 2024 According to a further embodiment of the process, it is provided that in step a), a wood-based material with a binder content of less than 15%, in particular less than 10%, preferably in the range between 0% and 6% is provided. This process makes it possible to produce wood-based panels with a very low binder content (“low-glue” panels) or even free of binders (0% binder content: “glueless” panels). This is possible through the combination of several measures, in particular through the use of high temperatures (utilization of the properties of lignins,the natural "adhesives" in the wood) as well as by the rapid cooling and the stabilizing holding pressure. For this embodiment, it is further proposed that glue and / or bio-glue be used as binding agents. Glues and bio-glues are very proven and high-performance binding agents for wood-based materials. A further embodiment of the process provides that in step a), fine wood chips are provided for the production of flat-pressed boards and / or long chips are provided for the production of coarse particle boards or OSB boards. By selecting the type of chips and their length, the type of board to be produced and its mechanical properties can be determined. According to a further embodiment of the process, it is provided that in step a), wood fibers are provided for the production of wood fiber boards, for example, medium-density fiber boards or MDF boards or high-density fiber boards or HDF boards.The wood fiber boards produced preferably have smooth surfaces on both sides. The type of fiber and its length can also determine the type of board to be produced and its mechanical properties. The wood fiber boards produced in this way differ from wood fiber boards produced using a wet process in that they have smooth surfaces on both sides, since such wood fiber boards do not have smooth surfaces, but rather have a grid-like imprint caused by the screen mesh. AC / AC 230725WO December 20, 2024 The invention is explained in more detail below with reference to a drawing that merely represents a preferred embodiment. The drawing shows: Fig. 1: a continuously operating press known from the prior art for producing a wood-based panel for implementing the method according to the invention,Fig. 2: a cyclically operating press known from the prior art for producing a wood-based panel for carrying out the method according to the invention, and Fig. 3: a diagram with the parameters of the method according to the invention. Fig. 1 shows a continuously operating press 1 known from the prior art for producing a wood-based panel for carrying out the method according to the invention. The press 1 is a continuously operating press which has two endlessly circulating steel belts 2, namely an upper steel belt 2A and a lower steel belt 2B. The steel belts 2 are guided around several rollers 3, of which at least one roller 3A per steel belt 2 has a drive 4 (e.g., an electric motor) to drive the rollers 3 and the steel belts 2 (the direction of movement of the steel belts 2 is indicated by arrows in Fig. 1). The steel belts 2 are arranged such thatthat a gap 5 is formed between the upper steel belt 2A and the lower steel belt 2B, which extends from the inlet 6 of the press 1 to the outlet 7 of the press 1. The gap 5 has a variable gap width 8 and serves to receive the wood material to be processed and to guide it through the press 1 along a transport direction TR. The gap 5 can be divided along the transport direction TR into a narrowing section ("inlet" of the press, gap width 8 decreases), a parallel section (gap width 8 remains approximately constant), and a widening section ("outlet" of the press, gap width 8 increases). AC / AC 230725WO December 20, 2024 The press 1 has several vertically extending frame elements 9, which are connected to one another via stiffening beams 10 running along the transport direction TR. The frame elements 9 have recesses 11,through which the steel belts 2 can be guided. The press 1 also has several hydraulic press cylinders 12 in its upper area, which can transmit pressing forces to the material via the steel belts 2. The press cylinders 12 are mounted on the frame elements 9, for example, in the recesses 11 of the frame elements 9. Numerous press cylinders 12 are provided along the transport direction TR, allowing the pressure to be adjusted very precisely – and differently along the transport direction TR. Furthermore, it can be provided that several press cylinders 12 are arranged next to one another transversely to the transport direction TR (hidden in Fig. 1) in order to achieve a uniform pressure distribution in the transverse direction. In the press 1 shown in Fig. 1, press cylinders 12 are arranged only above the gap 5; below the gap 5, however, pressure distribution plates 13 are provided, which are also mounted on the frame elements 9.for example, in the recesses 11 of the frame elements 9. The pressure distribution plates 13 can achieve a uniform pressure distribution and prevent the pressure in the area of ​​the frame elements 9 from being significantly higher than between the frame elements 9. In addition, the press 1 has heating plates 14, namely an upper heating plate 14A and a lower heating plate 14B. The upper heating plate 14A is arranged above the gap 5 (e.g., below the press cylinders 12), and the lower heating plate 14B is arranged below the gap 5 (e.g., above the pressure distribution plates 13). The heating plates 14 preferably have numerous holes or channels (not shown in Fig. 1) so that a heating or cooling medium (e.g., oil) can flow through the heating plates 14 in order to set the desired temperature. The heating plates 14 also have sufficient flexibility,so that the width of the gap 5 can be variably adjusted along the transport direction TR by the pressing cylinders 12 elastically deforming the heating plates 14 (slightly). Between the steel belts 2 and the heating plates 14 are roller bars 15, which are connected to each other and form an endless "roller bar carpet" circulating around rollers 16. The roller bars 15 can be divided into upper roller bars 15A and lower roller bars 15B.wherein the upper roller bars 15A are arranged above the gap 5 and within the upper steel belt 2A, and wherein the lower roller bars 15B are arranged below the gap 5 and within the lower steel belt 2B. The roller bars 15 allow - like a needle bearing - a low-friction relative movement between the steel belts 2 (moving in the transport direction TR) and the heating plates 14 (not moving in the transport direction TR) and the components connected thereto (e.g. the press cylinders 12 or the pressure distribution plates 13). Preferably, the roller bars 15 roll without a drive between the steel belts 2 and the heating plates 14, while transferring the pressing pressure and the thermal energy. In the area of ​​the inlet 6, the press 1 has a plurality of inlet rollers 17 which are adjustably mounted and can act on the steel belts 2 in order to change the geometry of the inlet 6 and adapt it to different applications. Unlike shown in Fig.1,Optionally, frame elements 9 with press cylinders 12 can also be arranged in the area of ​​the inlet 6 of the press 1. A continuously operating press is known, for example, from DE 102017110882 B4. The press 1 shown in Fig. 1 has an upper pressing device 1A and a lower pressing device 1B, which are separated from each other by the gap 5, but are nevertheless connected to each other by the frame elements 9. The upper press device 1A comprises the upper steel belt 2A, the upper roller bars 15A, the upper heating plate 14A, and the press cylinders 12. The lower press device 1B comprises the lower steel belt 2B, the lower roller bars 15B, the lower heating plate 14B, and the pressure distribution plates 13. AC / AC 230725WO December 20, 2024 Fig. 2 shows a cyclically operating press 1' known from the prior art for producing a wood-based panel for carrying out the method according to the invention. Those features of the press,which have already been described in connection with Fig.1, are provided with corresponding reference numerals in Fig.2. The essential difference to the continuously operating press 1 shown in Fig.1 is that the material to be processed by the press in the intermittently operating press 1' from Fig.2 is not moved during the pressing process, but remains stationary. Therefore, the press 1' from Fig.2 also has no rotating steel belts 2 and no rotating roller bars 15. Nevertheless, even with an intermittently operating press 1', it has proven advantageous to introduce the material from one side (inlet 6) into the gap 5 of the press 1' and - after the pressing process - to remove the produced material plate from the gap 5 of the press 1' from the opposite side (outlet 7). Thus, even with the intermittently operating press 1', a (preferred,(although not mandatory) "transport direction" TR. Since neither steel belts 2 nor roller bars 15 are present, in the press 1' shown in Fig.2, direct contact occurs between the two heating plates 14 (i.e., the upper heating plate 14A and the lower heating plate 14B) and the material to be processed during the pressing process. As with the press 1 in Fig.1, the pressing forces in the press 1' in Fig.2 are generated by pressing cylinders 12, which can also cause a change in the gap width 8. The press 1' from Fig.2 also has several vertically extending frame elements 9, which are connected to one another via stiffening beams 10. The frame elements 9 have recesses 11, which serve, for example,to be able to pass the two heating plates 14 through the frame elements 9. A cyclically operating press is known, for example, from DE 202012104004 U1. The press 1' shown in Fig. 2 also has an upper pressing device 1A' and a lower pressing device 1B', which are separated from each other by the gap 5, but are nevertheless connected to each other by the frame elements 9. The upper AC / AC 230725WO December 20, 2024 pressing device 1A' comprises the upper heating plate 14A and the pressing cylinders 12. The lower pressing device 1B' comprises the lower heating plate 14B. Fig. 3 shows a diagram with selected parameters of the method according to the invention. The method can be carried out, for example, on the press 1 shown in Fig. 1 or on the press 1' shown in Fig. 2. On the first (horizontal) axis in Fig. 3, the time t is shown (unit: minutes,Seconds). Several parameters are shown on the second (vertical) axis in Fig. 3: First, the second axis shows the temperature T (unit: °C), which refers to the temperature T in the material (in the center of the material plate). The temperature T can be measured, for example, by wires inserted into the material for measuring purposes. The second axis also shows the pressure P (unit: bar), which refers to the pressure P prevailing in the press cylinders 12 of the press 1, 1'. Due to Newton's third law ("force equals counterforce"), the pressing force exerted by the press cylinders 12 roughly corresponds to the contact force acting on the material. Nevertheless, the contact pressure differs from the pressure in the press cylinders because the two pressures act on different sized effective areas; the factor can vary from press to press. Finally, the third (vertical) axis shows the gap width 8 (unit: mm).i.e., the distance between the steel strips 2 (Fig. 1) or between the heating plates 14 (Fig. 2). The parameter curves shown in Fig. 3 are explained below in chronological order. A first time t1 denotes the start of the pressing process. This time is defined as the time at which a pressure P (key in Fig. 3: "Pressure") first reaches or exceeds a value of 1 bar. The pressure P rises very rapidly and reaches or exceeds a pressure of 100 bar at a second time t2. The increase in pressure P has the immediate consequence that the gap width 8 (key in Fig. 3: "Distance") decreases until the gap width 8 reaches a value of approximately 2.2 mm at a third time t3. A working pressure PA is set that lies approximately in the range between 100 bar and 115 bar.and kept as constant as possible. Since the heating plates 14 are heated (key in Fig. 3: "Hot plate temperature above" approximately 250°C), the temperature T in the material (key in Fig. 3: "MT 2" and "MT 4") rises upon contact with the heating plates 14, starting from an initial temperature TA (e.g. room temperature; here approximately 30°C) and approaches the temperature of the heating plates 14 up to a maximum value Tmax of approximately 230°C. Due to temperature-induced effects, there is a variance around the desired pressure value, which, however, rapidly decreases during oscillation around the desired value. At a fourth time t4, the pressure P is 100 bar and is rapidly reduced until the pressure P reaches a pressure P of 20 bar at a fifth time t5. The rapid pressure drop between the fourth time t4 and the fifth time t5 causes the gap width 8 to increase slightly (to approximately 2.5 mm); nevertheless, the contact between the press and the material is maintained, since the gap width 8 is only slightly increased and the compressed and not yet fully consolidated material expands again as a result of the reduced pressure as far as the gap width 8 allows. The pressure and temperature drop occur in a controlled manner, with the pressure P being reduced from the working pressure PA to a holding pressure PH which is approximately 20 bar or less, and with the temperature T falling from the maximum temperature Tmax to a holding temperature TH which is approximately in the range of 180°C. The pressing process is terminated at a sixth time t6, which (in analogy to the first time t1) is defined as the timein which a pressure P again reaches or falls below a value of 1 bar. The pressing process thus begins at the first time t1 and ends at the sixth time t6. For simplicity, the pressing process can be divided into four phases: a pressure increase phase (first time t1 to second time t2), a high pressure phase (second time t2 to fourth time t4), a pressure reduction phase (fourth time t4 to fifth time t5) and a holding phase (fifth time t5 to sixth time t6). Of particular interest is the pressure reduction phase, which in the process shown in Fig. 3 lasts, for example, approximately 4 seconds (t4 to t5), during which the pressure is reduced by approximately 80 bar. The pressure drop is therefore approximately 20 bar per second. As a result of the rapid pressure reduction, the temperature in the material also drops quickly (albeit with a slight time delay). The temperature drop takes about 1.5 seconds,whereby the temperature drops by approximately 50°C (Tmax -> TH). The temperature drop is therefore approximately 33°C per second. Alternatively, the process can be divided into the phases "heating", "cooling by controlled pressure relief" and "consolidation". Referring to Fig. 3, the "heating" phase begins as soon as the temperature T rises from the initial temperature TA and ends when the pressure drop begins (fourth time t4). The second phase "cooling by controlled pressure relief" follows immediately thereafter, i.e. it begins when the pressure drop begins (fourth time t4) and transitions into the third phase "consolidation" when the holding temperature TH is reached or when the holding pressure PH is reached (fifth time t5). AC / AC 230725WO 20 December 2024 List of reference symbols: 1, 1': press 1A, 1A': upper pressing device 1B, 1B': lower pressing device 2: steel belt 2A: upper steel belt 2B: lower steel belt 3,3A: Roller (for steel belt 2) 4: Drive 5: Gap 6: Inlet 7: Outlet 8: Gap width 9: Frame element 10: Stiffening support 11: Recess 12: Press cylinder 13: Pressure distribution plate 14: Heating plate 14A: Upper heating plate 14B: Lower heating plate 15: Roller bar 15A: Upper roller bar 15B: Lower roller bar 16: Roller (for roller bar carpet) 17: Inlet roller TR: Transport direction t: Time t1-t6: Time AC / AC 230725WO December 20, 2024 T: Temperature TA: Starting temperature TH: Holding temperature Tmax: Maximum temperature P: Pressure PA: Working pressure PH: Holding pressure PK: Contact pressure AC / AC 230725WO December 20, 2024,

Claims

December 20, 2024 P a t e n t a n s p r ü c h e 1. A method for producing a material board, in particular a wood-based board, from a material, comprising the following steps: a ) Bereitstellen von wenigstens einer Schicht eines Werkstoffs, insbesondere a material containing wood chips and / or wood fibers, b ) Bereitstellen einer Presse (1, 1‘), umfassend: ^ eine obere Presseinrichtung (1A, 1A‘) und eine untere Presseinrichtung (1B, 1B'), between which a gap (5) is formed to accommodate the material, ^ wobei die obere Presseinrichtung (1A, 1A‘) und / oder die untere Pressing device (1B, 1B') has hydraulic pressing cylinders (12) which can change the gap width (8) between the upper pressing device (1A, 1A') and the lower pressing device (1B, 1B') and can transmit pressing forces to the material, and ^ wobei die obere Presseinrichtung (1A, 1A‘) und / oder die untere Pressing device (1B, 1B') has a heating device, in particular a heating plate (14A, 14B), which can at least indirectly transfer heat to the material, c ) Pressen des Werkstoffs in dem Spalt (5) zwischen der oberen Pressing device (1A, 1A') and the lower pressing device (1B, 1B'), d ) Erwärmen des Werkstoffs in dem Spalt (5) zwischen der oberen Pressing device (1A, 1A') and the lower pressing device (1B, 1B'), ^ wobei die Schritte c) und d) wenigstens teilweise gleichzeitig stattfinden,d a d u r c h g e k e n n z e i c h n e t , d a s s the contact pressure (PK) acting on the material during step c) is reduced to a contact pressure (PK) which is in the range between 10 N / cm² and 150 N / cm², in particular between 30 N / cm² and 100 N / cm². - 2 - 2. Method according to claim 1, d a d u r c h g e k e n n z e i c h n e t , d a s s the pressure (P) of the press cylinders (12) during step c) is reduced from a working pressure (PA) to a holding pressure (PH) which is in the range between 5 bar and 40 bar, in particular between 10 bar and 30 bar.

3. Method according to claim 1 or claim 2, d a d u r c h g e k e n n z e i c h n e t , d a s s the reduced contact pressure (PK) and / or the reduced holding pressure (PH) is maintained for at least 10 seconds, in particular at least 20 seconds.

4. Method according to one of claims 1 to 3, d a d u r c h g e k e n n z e i c h n e t , d a s sthe temperature (T) is lowered from a maximum temperature (Tmax) to a holding temperature (TH) which is in the range between 120°C and 220°C, in particular between 140°C and 180°C.

5. Method according to one of claims 1 to 4, d a d u r c h g e k e n n z e i c h n e t , d a s s the holding temperature (TH) is maintained for at least 10 seconds, in particular at least 20 seconds.

6. Method according to one of claims 1 to 5, d a d u r c h g e k e n n z e i c h n e t , d a s s During step c), the contact pressure (PK) acting on the material is reduced, wherein the contact pressure (PK) is reduced by at least 50 N / cm², in particular by at least 100 N / cm², preferably by at least 200 N / cm².

7. The method according to one of claims 1 to 6, AC / AC 230725WO December 20, 2024 - 3 - d a d u r c h g e k e n n z e i c h n e t , d a s s During step c), the contact pressure (PK) acting on the material is reduced at a rate of at least 100 N / cm²s, in particular at least 200 N / cm²s.

8. The method according to any one of claims 1 to 7, d a d u r c h g e k e n n z e i c h n e t , d a s sDuring step c), the pressure (P) of the press cylinders (12) is reduced from a working pressure (PA) to a holding pressure (PH), wherein the pressure (P) of the press cylinders (12) is reduced by at least 20 bar, in particular by at least 40 bar, preferably by at least 60 bar.

9. Method according to one of claims 1 to 8, d a d u r c h g e k e n n z e i c h n e t , d a s s During step c), the pressure (P) of the press cylinders (12) is reduced at a rate of at least 10 bar / s, in particular at least 15 bar / s.

10. The method according to one of claims 1 to 9, d a d u r c h g e k e n n z e i c h n e t , d a s s During step c), the gap width (8) is increased to a value in the range between +2% and +20%, in particular between +4% and +15% of the gap width (8).

11. The method according to one of claims 1 to 10, d a d u r c h g e k e n n z e i c h n e t , d a s sDuring step c), the temperature (T) in the material is reduced by at least 20°C, in particular at least 30°C, preferably at least 40°C.

12. The method according to any one of claims 1 to 11, AC / AC 230725WO December 20, 2024 - 4 - d a d u r c h g e k e n n z e i c h n e t , d a s s During step c), the temperature (T) in the material is reduced at a rate of at least 10°C / s, in particular at least 20°C / s, preferably at least 30°C / s.

13. The method according to any one of claims 1 to 12, d a d u r c h g e k e n n z e i c h n e t , d a s s during step d) the temperature (T) in the material is increased to at least 130°C, in particular at least 150°C, preferably at least 180°C.

14. Process according to one of claims 1 to 13, d a d u r c h g e k e n n z e i c h n e t , d a s s During step d), the temperature (T) in the material increases strictly monotonically for at least 20 seconds, in particular for at least 30 seconds.

15. The method according to any one of claims 1 to 14, d a d u r c h g e k e n n z e i c h n e t , d a s sthe temperature (T) in the material is 150°C or more, in particular 180°C or more, for at least 10 seconds, in particular at least 20 seconds.

16. Method according to one of claims 1 to 15, d a d u r c h g e k e n n z e i c h n e t , d a s s in step b) a cyclically operating press (1') is provided, ^ wobei die obere Presseinrichtung (1A‘) durch mehrere Presszylinder (12) and an upper heating plate (14A) is formed, and ^ wobei die untere Presseinrichtung (1B‘) durch eine untere Heizplatte (14B) is formed.

17. The method according to any one of claims 1 to 15, d a d u r c h g e k e n n z e i c h n e t , d a s s AC / AC 230725WO December 20, 2024 - 5 - in step b) a continuously operating press (1) is provided, ^ wobei die obere Presseinrichtung (1A) durch mehrere Presszylinder (12), an upper heating plate (14A), an upper steel belt (2A) and upper rolling bars (15A) are formed, ^ wobei die untere Presseinrichtung (1B‘) durch eine untere Heizplatte (14B), several pressure distribution plates (13), a lower steel belt (2B) and lower rolling bars (15B) are formed, ^ wobei die Stahlbänder (2A, 2B) derart um Rollen (3, 3A) umlaufend gelagert are that the gap (5) for receiving the material is formed between the steel bands (2A, 2B), and ^ wobei die Rollstäbe (15A, 15B) derart um Rollen (16) umlaufend gelagertare arranged between the steel belts (2A, 2B) and the heating plates (14A, 14B) and allow a relative movement between the steel belts (2A, 2B) and the heating plates (14A, 14B).

18. Method according to one of claims 1 to 17, d a d u r c h g e k e n n z e i c h n e t , d a s s in step a), the wood-based material is provided in multi-layer form, in particular in 3-layer, 5-layer, or 7-layer form, in particular with at least one middle layer, at least one lower cover layer, and at least one upper cover layer.

19. The method according to any one of claims 1 to 18, d a d u r c h g e k e n n z e i c h n e t , d a s s in step a), a wood-based material having a moisture content in the range between 2% ATRO and 40% ATRO, in particular between 5% ATRO and 30% ATRO, particularly preferably between 10% ATRO and 25% ATRO is provided.

20. Process according to one of claims 1 to 19, d a d u r c h g e k e n n z e i c h n e t , d a s s AC / AC 230725WO December 20, 2024 - 6 - in step a), a wood-based material with a binder content of less than 15%, in particular less than 10%, preferably in the range between 0% and 6% is provided.

21. Process according to claim 20, d a d u r c h g e k e n n z e i c h n e t , d a s s glue and / or bio-glue are used as binding agents.

22. Method according to one of claims 1 to 21, d a d u r c h g e k e n n z e i c h n e t , d a s s in step a), fine wood chips for the production of flat-pressed boards and / or long chips for the production of coarse particle boards or OSB boards are provided.

23. Process according to one of claims 1 to 22, d a d u r c h g e k e n n z e i c h n e t , d a s s In step a), wood fibers are provided for the production of wood fiberboards, for example medium-density fiberboards (MDF) or high-density fiberboards (HDF), wherein the produced wood fiberboards preferably have smooth surfaces on both sides. AC / AC 230725WO December 20, 2024

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