Method and device for producing material panel, and material panel

Abstract

The invention relates to a method and a device for producing a sheet of material from at least one material which is dispersed to form a pressure pad and which is mixed with at least one adhesive which can be cured by heat and / or pressure. According to the invention, the pressure pad (1) is compressed in a twin-belt press (10) having a steel strip (12), the temperature of which is higher than that of the pressure pad (1) and which is heated by heat conduction, at least one cover layer (2) resting on the steel strip (12) being heated to a temperature higher than the curing temperature of the adhesive and at least partially cured, according to the invention, an uncured portion of the pressure pad (1), in particular an uncured intermediate layer (3), is heated to a temperature above the curing temperature of the adhesive in a downstream injection press (20) by introducing a temperature-controlled fluid (5) and cured, the fluid (5) being introduced through the pressure pad (1) through one or both cover layers (2). The invention also relates to a material panel () produced by such a method and / or in such a device.

Description

Technical Field

[0001] According to the preamble of claim 1, the present invention relates to a method for producing a material plate from a material dispersed to form a pressure pad.

[0002] The present invention also relates to an apparatus for producing material plates according to the preamble of claim 26.

[0003] Furthermore, the present invention relates to a material plate produced by the above-described method or in the above-described equipment according to technical solution 34. Background Technology

[0004] Producing material boards by pressing free-flowing or spread materials in a calender, intermittent press, or twin-belt press is an existing technology. A mixture of materials containing lignocellulose, such as wood, woody plants, or annuals, is spread into one or more layers with or without adhesives and cured into a pad by pressure and / or heat to form a stable material board. This material board can be flexible or tough (thin MDF boards made of fibers), but still retains a certain inherent compressive rigidity. Material boards for furniture making also exist, primarily particleboard (or multi-layered boards laminated with foil) or so-called OSB made from flattened chips. Substitution with plastics, waste wood, or other fillers is common practice.

[0005] During the production process, the material is mixed with an adhesive, which is typically methylene diphenyl isocyanate (MDI) or polymeric methylene diphenyl isocyanate (pMDI), urea-formaldehyde resin (UF) or melamine-reinforced urea-formaldehyde resin (MUF), or other curable adhesives.

[0006] Pressure pads can be produced or distributed in single or multiple layers. Particleboard is typically multi-layered and can also be distributed in a categorized manner, such that coarse material is arranged between the surface sides in a flat central plane, and a cover layer made of fine material is located on one or two surface sides. OSB boards are also multi-layered, but typically consist of multiple layers with different orientations, and the material dimensions vary accordingly.

[0007] There are also multi-layered composite panels, such as those with an inner particle layer (German: innen liegende Spanschichten (inner wood shavings layer)) covered by an outer fiber layer. Currently, the outer fiber or particle layer is also used in OSB production.

[0008] The distribution or production of pads is well known from the prior art and can be considered largely independent of this method. The production of single or multiple layers of pads inherently affects the material sheet as the product. Depending on the pads, the materials used, their humidity, layer structure, etc., the equipment or method is configured as required to achieve the desired quantity of material sheet.

[0009] Previously, press systems using a twin-belt design were typically over 20 meters long and required a complex overall setup within the press frame for heating, pressure generation, and load flow distribution. Furthermore, operating a twin-belt press correctly at this length is technically complex. Errors or problems during operation can cause considerable damage and downtime. Additionally, the steel construction and control technology themselves are complex, typically requiring operation and maintenance only by qualified professionals.

[0010] The development of these long and large presses benefited from the adhesives and mortises used in the past. Advances in environmental compatibility and the necessary improvements have driven further breakthroughs in this field, resulting in new adhesives having or requiring different settings in terms of pressure, temperature, and exposure time. Summary of the Invention

[0011] The object of this invention is to provide a method and apparatus that avoids the aforementioned disadvantages. In particular, it should be possible to divide the complex equipment technology of previously long and large devices into multiple sub-sections, which may be less prone to failure or damage. Furthermore, a material plate is provided that can also be produced with high quality in a simplified system. In particular, it should be possible to produce the material plate at a lower cost, especially in terms of investment and manufacturing costs.

[0012] In expanding this objective, it should be possible to improve the production speed and quality of existing adhesives, particularly aminophenol-based adhesives (UF, MUF, MUPF, PF, UFMP). It should also be possible to use bio-based adhesives (tannins and blended polymers, animal and plant proteins, lignin and blended polymers, carbohydrate-containing adhesives) as well as PVA, acrylic, epoxy, or MDI with advanced properties.

[0013] The present invention is based on a continuous method for producing a material board in which a material dispersed to form a pad is cured, the material being mixed with at least an adhesive capable of curing by heat and / or pressure.

[0014] The objective of this invention is achieved by continuously compressing a pressure pad in a double-belt press, wherein the temperature of the steel belt in the double-belt press is higher than that of the pressure pad, and heating is achieved through heat conduction.

[0015] In this process, at least one cover layer near the surface or adjacent to the steel strip is heated to a temperature higher than the curing temperature of the adhesive, and the cover layer is at least partially cured.

[0016] In this process, the uncured portion of the aforementioned pad, particularly the uncured intermediate layer, is heated to a temperature higher than the curing temperature of the adhesive in a downstream injection molding machine by introducing temperature-controlled fluids, and then cured.

[0017] The fluid is introduced or passes through the pressure pad via one or two covering layers.

[0018] Surprisingly, the present invention now recognizes that by using a heavy-duty twin-belt press for essentially only at least a portion of the curing of the cover layer, while the main portion of the curing of the pad or intermediate layer can be accomplished using a pure injection press, the investment in previously known continuously operating twin-belt presses of 25 meters or more in length can be significantly reduced. For example, this reduces the excessive length of the steel belts and rolling supports, as well as the corresponding investment required to guide and control them.

[0019] In particular, it has been recognized that, even though the overlay is partially or fully cured, it is still possible to inject heated fluids, such as steam, hot air or the like, into the pad to cure the intermediate layer, and subsequently obtain a fully cured material sheet with sufficient quality properties.

[0020] In this invention, partial or complete curing is understood to mean a portion of the pad or cover layer that is inherently stable or dimensionally stable and substantially no longer changes, even if chemical or physical reactions continue to occur within it. Therefore, although fluid may enter or exit the pad during the curing or near-curing of the cover layer, the elastic or decompression properties of the intermediate layer will not damage the pad or subsequent product itself after a two-belt press or during transition to an injection press.

[0021] Therefore, the present invention primarily recognizes that partially cured or cured overlays are partially elastic and sufficiently continuous so that they do not burst after board production due to internal vapor overpressure, as is the case with conventional surface cracking. Typically, this is due to the flow of cool ambient air into the pressure pad in the depressurization zone, or even due to the increased volume of the interlayer or pressure pad, or a cooling effect or a reduction in the internal pressure of the pressure pad.

[0022] In certain exemplary embodiments, the invention further proposes providing an environment of hot or temperature-controlled fluid, preferably free of moisture, to the depressurized pressure pad after the dual-belt press and before or at the start of the injection press. This measure can advantageously further accelerate the production process. This environment can be achieved, for example, by an insulated chamber or shell, or by an injection plate that provides a sufficient amount of fluid for the pressure pad to absorb, thereby increasing the pressure pad's volume.

[0023] When arranging a chamber or a certain type of housing, the opening with a high volume requirement for the pressure pad will create a vacuum in the area around the pressure pad. Therefore, as long as sufficient fluid is provided in the housing, the seal does not have to be absolutely tight.

[0024] Alternatively, decompression can be supported by actively introducing fluid, such as through overpressure. The opening gradient can be set in a controlled manner to avoid cracking in the surface layer or inside the pad.

[0025] Alternatively or additionally, the method may be performed such that, during decompression of the pressure pad, a subsequent compression zone replaces the lost volume. Air flowing outward against the transport direction or air flowing in the decompression zone is reabsorbed by the pressure pad, and / or the compression zone shifts excess volume within the pressure pad in the direction against the transport direction toward the decompression zone.

[0026] Advantageously, temperature-controlled fluid can be introduced into the compression zone, either alternatively or additionally, and the existing volume within the pressure pad can be shifted in the reverse direction of production to the decompression zone, and / or to increase the temperature already present in the intermediate layer therein.

[0027] Fluid can also be supplied, injected, and / or extracted at narrow sides. This typically occurs in conjunction with or radially opposite to processes on the surface. For compression and / or decompression areas, extreme sealing of the chamber or housing is only required in individual cases. Instead, walls with flexible seals or friction-reducing elements are sufficient to provide adequate shielding against environmental influences, for example, above or beside the circulation zone. Air leakage can be regulated by controlling appropriate pressure within the chamber or housing.

[0028] The following definitions and references will help in understanding this invention and its teachings:

[0029] The surface side refers to the planar side of the pad or material plate that contacts the belt, while the narrow side represents the thickness or height of the pad or material plate. The outer surface side contains the cover layer to be at least partially cured by the dual-belt press.

[0030] This invention relates to curing a cover layer on the outer surface side using a continuously operating dual-belt press. The term "cover layer to be partially cured" should not be confused with the terms used in pad manufacturing techniques for spreading or layering cover layers or multi-layer pads. Any type of single-layer or multi-layer pad can be used in this method or apparatus. For example, in the dual-belt press method, the near-surface spread layers of the pad can be at least partially cured, and thus, according to the invention, these layers are interpreted as "one" of the cover layer to be at least partially cured, which makes the dual-belt press relatively stable in terms of dimensions, while the intermediate layers are dimensionally unstable and bounce or increase in volume again in the decompression zone after the surface pressure of the dual-belt press is no longer present. The aforementioned intermediate layer may also consist of several different (spread) layers, but here it is defined as the area where the temperature required to initiate the adhesive setting process near the center plane of the pad has not yet been reached.

[0031] In summary, the use of the term "layer" in the described inventive apparatus or by the method described in the inventive does not refer to different layers of a (piece) pad, but merely to the thickness of the cured region adjacent to the steel belt of a dual-belt press or the thickness of the middle (region) of the pad in an injection press. Of course, the three layers of a three-layer pad may be aligned with the cured overlay and intermediate layers.

[0032] Another exemplary alignment may occur in a pad with five layered layers, with the top layer cured and the middle layer consisting of the remaining three layers in the middle of the pad.

[0033] Of course, only a portion of the outer layer of the multilayer pad can be cured by thermal conduction in a dual-belt press, or conversely, one or more layers can be cured by thermal conduction. In both cases, the layer is referred to as a “covering layer” according to the invention.

[0034] Therefore, the uncured area in the middle of the pad after the dual-belt press may include or may consist of several layers dispersed before the press, or the entire dispersed middle layer, or a portion of the dispersed middle layer.

[0035] According to the present invention, a pad of a dispersed monolayer material consisting of only one material (combination), such as fibers, can also be produced, wherein one or two outer regions of such a monolayer pad are cured into one or two cover layers, while the remaining uncured regions are cured by an injection press or cured in an injection press.

[0036] In the special case where only one surface is heated to establish a cured overlay, the present invention refers to the uncured intermediate layer or the remaining uncured material as an intermediate layer.

[0037] In addition to temperature, humidity or similar physically detectable limits can also be used as thresholds (starting values) for setting up the process, because some adhesives not only react to temperature or not at all, but also require a certain level of humidity or other basic conditions for the process to proceed chemically correctly.

[0038] Technically, the depth of curing, or at least the thickness of the partially cured surface layer, is largely determined by the conveying time or belt speed, material type, belt temperature, and / or the curing temperature of the adhesive, which are technical parameters that should be considered or adjusted during the production process.

[0039] The present invention also understands compression in a dual-belt press as heat transfer through surface contact only between the steel belt and the pressure pad, which physically requires at least an approximate "compression", even if it is only a very small approximate "compression".

[0040] This invention understands the material plate as a (almost) completely cured pad. Essentially, this is produced in a string from a device or individual unit and is cut into material plates by a common mitre saw (not shown in detail), then selectively cooled and stacked.

[0041] The belt used in an injection molding press can be made of steel thinner than that of a two-belt press, or of heat-resistant plastic that will not be damaged by the high radiant temperature of the steel belt in a two-belt press. The belt has openings for fluid passage and / or distribution.

[0042] If present, the upper and lower belts in each device preferably have the same design at the top and bottom, and are guided accordingly around the deflection roller or drive roller.

[0043] A twin-belt press can be designed as an isobaric press, but it can also be designed as a traditional continuous press, featuring rolling elements (such as rolling mats) arranged between the heating plates and the steel belt. Typically, the heating plates are heated by a hot fluid flowing through them.

[0044] To make the structure of the device according to the invention clearer, the various machines of the device may also be named: pre-press (optional), cover laminator (double belt press), injection press (curing) and calibration press (optional).

[0045] In the case of pre-compression, it should be noted that although optional heating according to the prior art is preferably carried out during degassing, curing will not or cannot occur in the pad because the curing temperature of the adhesive should not be reached. Typically, the aim is to control or regulate the method or equipment to be as close as possible to the curing temperature.

[0046] Regarding the curing temperature, this invention refers to the temperature at which the adhesive begins a chemical reaction and transforms into a dimensionally stable network or plasticized state. This reaction is irreversible for the vast majority of adhesives, provided it has been initiated with sufficient initial energy.

[0047] The capping layer cured in the capping press facilitates the transport of the pads and also covers the pads to minimize springback when switching between a dual-belt press and an injection press. This creates a certain packing density distribution (profile) across the (entire) thickness of the pad. However, it is possible, and even reasonable, to provide options for controlling or even intentionally enabling springback between individual units to create certain production conditions, such as facilitating fluid introduction into the pads due to negative pressure during decompression.

[0048] In addition to the procedural advantages of the present invention, the following features also include further characteristics that can be combined as needed to improve the method or apparatus:

[0049] Heated air, steam, preferably superheated steam, or a steam-air mixture can be used as the temperature-controlled fluid. These fluids have proven their value in heating the pressure pads upstream of the main press in the past.

[0050] Preferably, the dew point can be set using unsaturated air or a steam-air mixture, such that moisture in the fluid condenses only after entering the cover layer or in the pressure pad after passing through the cover layer. This prevents water stains or cover layer breakage.

[0051] Alternatively, it can be specified that the fluid reaches a limiting temperature and / or water content in the intermediate layer, which is suitable for curing the adhesive, preferably until the material sheet emerges from the injection press (appears). In addition to the limiting temperature, there are other physical limits that can activate curing, such as the water content present, pressure, and / or the concentration of hardener optionally achieved by adding a hardener to the fluid.

[0052] In a dual-belt press, a pressing pressure exceeding 1 or 2 N / mm² can be applied to the pressure pad. Preferably, the pressing pressure should not exceed 6 N / mm². Lower pressures are also possible. This is suitable for insulation boards or lightweight boards.

[0053] After leaving the dual-belt press, the cured cover layer should have a thickness of at least 1 mm, preferably greater than 2 mm, and most preferably 3 mm to 4 mm, in order to have sufficient inherent stiffness or dimensional stability.

[0054] Liquids and / or hardeners can be applied to the surface side of the press pad for adhesive application. This has a positive effect on the penetration-curing or speed of the surface layer. Application is typically performed from below and / or from above shortly before pressing.

[0055] An anti-caking agent can be applied to the steel belt of a twin-belt press and / or to the surface side of the pad before it comes into contact with the twin-belt press, so that the cover layer does not stick or adhere to the steel belt when it leaves the twin-belt press, and may cause the intermediate layer and / or the cover layer or the intermediate layer to crack at the transition.

[0056] After the pressure pad leaves the dual-belt press, the thickness of the at least partially cured coating can be determined. For this purpose, non-destructive testing methods can be employed.

[0057] These and other settings or adjustments can be used in the control or regulation apparatus or for performing the method to implement or optimize the method according to the invention and / or operation of the apparatus. Preferably, the above values ​​are used in the control or regulation system to adjust the thickness of the dual-belt press or the cover layer.

[0058] In an injection molding machine, the pressure pad can be pressed by a surface pressure of less than 0.75 N / mm², preferably by a surface pressure or pressing pressure of less than 0.6 N / mm² and most preferably by a surface pressure or pressing pressure of less than 0.5 N / mm².

[0059] Alternatively or cumulatively, a flat injection plate and / or a perforated roller with a cover for areas not facing the pressure pad can be used, and the injection plate and / or the perforated roller has openings for guiding and dispensing fluid to introduce fluid into the pressure pad.

[0060] In advantageous applications, the fluid is introduced into the pressure pad at a pressure greater than 0.5 bar, preferably greater than about 1.5 bar, and most preferably greater than 2 bar. This value can also be determined and / or set as the fluid exits or enters the injection plate.

[0061] The pressure pad can be guided through the injection press by means of at least one permeable strip located on one side of the surface, specifically for allowing fluid to pass through the permeable strip. This strip can be designed as a perforated metal or plastic strip, or as a braided or chainmail strip.

[0062] The belt can be compressed together with the pressure pad in the injection press, or compressed upstream of the injection press in the transport direction via a compression unit or calender, and / or subjected to thrust in the transport direction, preferably applied via the drive rollers of the calender or injection press.

[0063] After the middle layer of the material plate has cured, it can be compressed and / or held to nominal size between two strips, preferably steel strips, in a calibrating press, preferably with a surface pressure or pressing pressure of less than 2.5 N / mm².

[0064] Preferably, the cover layer of the material plate is smoothed, heated, and / or cooled in a calibration press.

[0065] Waste heat generated during the cooling process in the calibration press can be reused. For this purpose, it is preferable to install a heat pump, heat exchanger, or other cryogenic equipment actively connected to the calibration press. Particularly preferred is that the waste heat can be used in a portion of the equipment upstream of the calibration press in the transport direction.

[0066] The nominal thickness of the produced material sheets is preferably greater than 8 mm, preferably greater than 30 mm, and most preferably greater than 60 mm. Solid sheets are preferably produced with a thickness of up to 80 mm. Defective pads or material sheets, especially those that have not undergone the necessary curing, can be discarded in a waste container after the injection press or after the calibration press. This protects the finishing process of the material sheets using miter saws, grinding devices, and / or transport rollers from the brittle, partially hardened material sheets.

[0067] Before entering the twin-belt press, the produced or distributed pads can be pre-compressed to degas in a pre-press. Preferably, degassing is performed there by means of at least one air-permeable fabric belt, and most preferably, no preheating is performed.

[0068] Depending on the process application, the sheet of material cured in or emerging from the injection press may be subjected to traction in the transport direction. This can be achieved, for example, by the drive rollers of the injection press, by a calibration press, or by a separate calender.

[0069] Control or regulating devices can be used to control or regulate production speed or the depth of individual equipment components, preferably dual-belt presses, injection presses, and / or calibration presses. Preferably, this is for controlling or regulating a master-slave system, wherein only a single device is provided as the master or reference variable. Preferably, a curing injection press or a dual-belt press, or its production speed, is used.

[0070] Preferably, a single or multiple, preferably three or five-layer, pressure pad is used in the equipment or in the method, which is suitable for producing MDF, HDF, particleboard, OSB (shaving board), and mixed boards made of fibers and chips, wherein the fibers are preferably arranged in the outer layer or in the insulation board.

[0071] Pressure pads can also be used to produce insulation panels with only one or two outer layers.

[0072] At least in proportion, aminophenol-based adhesives, methylene diphenyl isocyanate (MDI), polymeric methylene diphenyl isocyanate (pMDI), urea-formaldehyde resin (UF), melamine-reinforced urea-formaldehyde resin (MUF), bio-based resins, preferably containing or not containing mixed polymers of tannins, plant and / or animal proteins, containing or not containing mixed polymers of lignin, carbohydrate-containing adhesives, PVA, acrylic and / or epoxy resins can be used as curable adhesives in pads.

[0073] Due to the method and / or the equipment, an intermediate region is formed between two presses, a dual-belt press, and an injection press, in which the pressure pad is switched from one press to the next in a guided or unguided manner. In most cases, due to the lack of curing of the adhesive in the intermediate layer, the adhesive cannot perform its plasticizing function; therefore, the intermediate layer is elastic, and the volume of the pressure pad compressed after the dual-belt press will increase.

[0074] In this way, the pad or uncured intermediate layer can be inflated or rebounded in a depressurization zone after leaving the dual-belt press, wherein the pad can be supplied with a temperature-controlled fluid in this depressurization zone, on at least one surface side and / or on the narrow side, for bonding into the pad. This can be achieved by flushing (flooding) the area around the expanded pad with fluid. To reduce the required input, flushing is preferably performed in a chamber, housing, or suitable tunnel in this area. In addition to being supplied, the pad can also be actively pressurized with fluid, for example by overpressure in the chamber, housing, or tunnel.

[0075] Following the dual-belt press, the pressure pad can be compressed in a compression zone, preferably on the inlet side of the injection press. Preferably, in this compression zone, the temperature-controlled fluid of the pressure pad is injected onto at least one surface side and / or passively absorbed on the surface side, most preferably on the opposite surface side.

[0076] In a particularly preferred and independent exemplary embodiment, during the production of the cover layer, the pressure pad is compressed in a dual-belt press to 0 to 20%, preferably 0 to 10%, and most preferably + / - 5% above the nominal size of the material sheet. In other words, the compression in the dual-belt press corresponds to up to 120%, preferably up to 110%, and most preferably 95% to 105% of the height of the finished material sheet.

[0077] In a further distinguishing embodiment, after the dual-belt press, the springback is limited to less than 25%, preferably less than 15%, and particularly less than 10%.

[0078] In addition to the conventional layers constructed symmetrically about the center plane of the pad or material board, it is also possible to have only one overlay layer that is at least partially or completely cured, with an uncured intermediate layer or its area extending to the other side of the surface. This type of pad is particularly used in the manufacture of flexible or relatively rigid insulation boards, especially those based on natural fibers. However, MDF boards, such as those used for furniture back panels, often also have a smooth and compacted surface on one (surface) side, while the other side corresponds to the intermediate layer or residual layer.

[0079] In addition to or replacing the aforementioned injection fluid options, other alternative designs are also possible. For example, the fluid can be injected and withdrawn alternately in the transport direction. The fluid can be injected into the pressure pad on one side and withdrawn on the other side. This process can be performed alternately or cyclically in the transport direction at predetermined intervals. The narrow side can be integrated into a fluid guide with positive or negative pressure.

[0080] Materials used for padding can include pure lignocellulosic materials and / or mixtures of lignocellulosic materials, such as natural wood, recycled wood, woody plants, waste wood, plant residues, and / or annual plants. Filler materials can be added as needed, especially for lightweight boards.

[0081] The purpose of the apparatus for producing a material sheet from at least one material dispersed to form a pad and mixed with at least one adhesive capable of curing by heat and / or pressure is achieved by: a double-belt press arranged in the transport direction of the pad, the double-belt press having two infinitely circulating steel belts for compressing and heating the pad, and for at least partially curing at least one layer or cover layer resting on the steel belts by heating to a temperature above the curing temperature of the adhesive; and an injection press arranged downstream of the double-belt press, the injection press having at least one means for injecting a temperature-controlled fluid into one surface side of the pad for temperature-controlled (modulation, tempering) and curing of the uncured portion or intermediate layer of the pad.

[0082] The process engineering features and positive improvements listed in this method can be used in conjunction with equipment that has the aforementioned features.

[0083] In an advantageous manner, the features listed in the table below can be accumulated with these or the following advantageous features to improve the solution of the device or method as needed, either in combination or independently:

[0084] Preferred devices for injecting temperature-controlled fluids are injection plates, injection rollers, or injection nozzles, preferably having openings for preferably providing heated air, steam, superheated steam, and / or steam-air mixtures.

[0085] An anti-caking agent application section can be arranged for applying an anti-caking agent to the steel belt of a twin-belt press and / or an additive application section for applying additives and / or water to the pressure pad upstream of the twin-belt press.

[0086] One or two infinitely looping belts can be arranged in the injection molding machine. These belts are preferably designed as perforated metal or plastic belts, braided belts, or chainmail belts.

[0087] The compression unit and / or calender can be located in or near the injection press.

[0088] A calibration press and / or discharge vessel can be located downstream of the injection press. The discharge vessel can also be located downstream of the calibration press as a separate unit.

[0089] Semi-finished material sheets or uncured pads are not suitable for feeding into the finishing process. Deflectors can be arranged to force the hardened cover layer toward the discharge container.

[0090] The calibration press for recovering waste heat from the material plate is operatively connected to a cryogenic device, preferably to a heat exchanger, heat pump, and / or components of equipment upstream of the calibration press. The cryogenic device is preferably suited for use with media at temperatures below 60°C, most preferably below 40°C, in order to save energy.

[0091] A decompression zone with chambers, tunnels, housings and / or injection plates can be arranged between the dual-belt press and the injection press to supply temperature-controlled fluid to the pressure pad, thereby increasing its volume.

[0092] A solution for achieving the purpose of producing new material plates by using the method according to the invention and / or producing material plates in the apparatus according to the invention.

[0093] In a separate and particularly preferred embodiment, the method or apparatus comprises three stages:

[0094] a) Curing is performed at least partially on one or both sides in a dual-belt press;

[0095] b) Curing the remaining uncured areas or intermediate layers in an injection press or vapor press; and

[0096] c) Calibrate / adjust the thickness of the material plate in a dual-belt press.

[0097] Finally, it should be pointed out again that curing does not necessarily mean the complete and final chemical development of the entire adhesive. Rather, curing should be initiated or accelerated by exceeding the curing temperature so that further process or manufacturing steps can be carried out, at which temperature the adhesive (more and more) reacts.

[0098] This further process or manufacturing step may be smothering the surface, calibrating the overall thickness, calibrating the different thicknesses of each layer, and / or embossing the surface.

[0099] Another advantage can be obtained by using or combining the following features:

[0100] The infinity belt used in the injection press can be dried and / or cleaned in the reflux via a cleaning device. This ensures that the quality of the compression and / or the quality of the fluid injected into the pressure pad remains consistent. Such units for circulating belts can also be installed in two other presses.

[0101] The injection plate may have openings for the fluid to be injected into the pressure pad. On the other side of the pressure pad, the injection plate may also introduce fluid or apply a corresponding vacuum to allow fluid to pass through the pressure pad. The introduction of fluid into the pressure pad and heat dissipation allow the adhesive to cure, thus forming a material plate. The injection plate can be heated to prevent droplet formation or water generation due to condensation. A preheater can be installed for the circulating belt in any press used.

[0102] Optionally, a calibration press can be arranged downstream of the injection press, which uses (multiple) belts to adjust or recompress the thickness of the material sheet. These belts are preferably designed to be steel. The steel belts can be cooled by a cooling plate to further strengthen the material sheet. The steel belts can also create a smooth surface.

[0103] A discharge container can be arranged downstream of the injection press to receive defective sheets and / or incompletely cured material plates or pads.

[0104] Deflectors can be installed to force the cured coating towards the discharge container. The discharge container can also be located after the calibration press or any other press. The discharge container typically has a pulverizing device to further transport the discharged material in a pulverized form.

[0105] Preferably, the steel belts mentioned and used in dual-belt presses or calibration presses are impermeable. They may have particularly smooth surfaces. Thus, energy transfer is optimized and / or the surface of the cover layer is flat or smoothed. Enclosed steel belts are best suited for conducting energy or heat transfer to or from the pad or to the pad's surface / cover layer. Depending on the expected temperature and required force, any belt with thermally conductive properties can be used as a steel belt. Therefore, steel belts or other belts are preferably (airtightly) sealed or enclosed to prevent liquid penetration, with exceptions possible in calibration presses. Attached Figure Description

[0106] Further advantageous measures and designs for achieving the object of the invention will become apparent from the dependent claims and the following description taken in conjunction with the accompanying drawings, wherein:

[0107] Figure 1 A schematic side view of a continuous arrangement of a dual-belt press and injection press according to the invention, having an optional pre-press in the forward transport direction and an optional calibration press in the rear transport direction; and

[0108] Figure 2 This is a possible enlarged view of an alternative transition between a dual-belt press and an injection press according to another exemplary embodiment of the invention. Detailed Implementation

[0109] The same reference numerals are generally used for identical or similar machine parts or equipment components. In this invention, "in front of the transport direction, in the transport direction, or in the opposite direction of the transport direction" is understood to relate to the direction or location along which the pressure pad, which is cured to form the material plate, typically passes through the equipment. The equipment according to the invention comprises at least two separate presses, which together form a technical system for carrying out the method.

[0110] according to Figure 1 The distributed pads 1 are conveyed along the transport direction 8 to a double-belt press 10 via a transport device (not shown), which typically operates below the distributing device (not shown) to produce a shaped belt of pads 1. Optionally, the pads can be pre-compressed in a pre-press 6 prior to this conveying to remove as much air as possible.

[0111] During compression in the twin-belt press 10, or optionally without compression, heat is transferred between the steel belt 12, which circulates infinitely above the deflecting roller 14, and the pressure pad 1 after contact at the top and bottom, and the cover layer 2 of the pressure pad 1 is cured. The depth or thickness of the cured cover layer 2 is determined substantially by the conveying time / belt speed, material type, belt temperature, and / or the curing temperature of the adhesive. A heating plate 11 is arranged to heat the steel belt and provide the required pressing pressure. This heating plate 11 can withstand forces applied via the press frame using a hydraulic cylinder (not shown) and can rise and fall. A roller circulation system 13 can be arranged to provide rolling support for the steel belt 12 relative to the heating plate 11. An anti-caking agent applicator 15 can be arranged to apply an anti-caking agent to the steel belt 12. The anti-caking agent can also be applied to the surface or surface side of the pressure pad. Furthermore, it is conceivable to apply additives or water to the surface side of the pressure pad 1, for example, to accelerate curing in the cover layer 2, or to generate a steam shock effect in the twin-belt press 10 that passes through the overheated steel belt 11 along the direction of the intermediate layer 3. For this purpose, an additive application unit 16 or a water spraying device can be arranged at an appropriate location.

[0112] Partially cured pad 1 exits from dual-belt press 10 and is then conveyed to injection press 20 along with an intermediate layer 3 that may have been heated but not yet cured. In injection press 20, pad 1 is transported and guided by belt 22. A spray plate 21 is arranged to cure the intermediate layer 3 or uncured areas by supplying a temperature-controlled fluid 5 to the pad 1. Instead of or along with the spray plate 21, a known steam roller (not shown) may be arranged, rolling over the pad 1 or belt 22 and otherwise encapsulated by a sheet of metal, such that the fluid-permeable steam roller dispenses fluid 5 only on the pad side. The amount or temperature of the fluid 5 is set such that the adhesive reaches the curing temperature and begins to harden across the entire cross-section of the pad.

[0113] The belt 22 is guided indefinitely by the drive roller 24 and deflected as needed by the deflection roller 26. A compression unit 27 can be arranged on the feed side of the injection press 20 and can adjust the feed or compression gradient for the pressure pad 1 via a corresponding adjustment device (not shown). Additionally or alternatively, a calender 25 can be arranged to initiate the compression of the pressure pad 1 and ensure a corresponding reduction in friction of the belt 22 on the injection plate 21. The calender 25 can be arranged as needed, preferably according to the process, for example, between the dual-belt press 10 and the injection press 20, within or after the injection press 20, or between the injection press 20 and an optional calibration press 30. The belt 22 can be dried and / or cleaned via a cleaning unit 23 during the return stroke. This ensures that the quality of the injected fluid 5 into the pressure pad 1 is always consistent. Cleaning units for circulating belts can also be arranged in two other presses.

[0114] The injection plate 21 has openings for the fluid 5 to be injected into the pressure pad 1, such as steam, hot air, or superheated steam. On the opposite side of the pressure pad 1, the injection plate 21 can also introduce the fluid 5 or apply a corresponding vacuum to allow the fluid to pass through the pressure pad 1. The introduction and dissipation of fluid in the pressure pad 1 cause the adhesive to cure and form a material plate 4. The injection plate can be heated to prevent droplet formation or water generation due to condensation. A preheater can be arranged for the circulating belt 22.

[0115] Optionally, a calibration press 30 may be arranged downstream of the injection press 20. This calibration press 30 uses a belt to adjust or recompress the thickness of the material plate 4. This belt is preferably designed as a steel belt 28. The steel belt 28 can be cooled by a cooling plate 29 to further strengthen the material plate. The steel belt can also provide a smooth surface.

[0116] A discharge container 7 can be arranged downstream of the injection press 20 to receive defective sheets and / or incompletely cured material plates 4 or pads 1. A deflector can be arranged to force the cured capping layer 2 toward the discharge container 7. The discharge container 7 can also be arranged after the calibration press. The discharge container 7 typically has a pulverizing device to further transport the discharged material in a pulverized form.

[0117] From the perspective of methods and technology, the process for manufacturing material plate 4 can be summarized as follows:

[0118] A pressure pad 1 is produced and fed into a twin-belt press 10 along the transport direction 8, where it is typically compressed and heated. A steel belt 12 is supported and heated by a heating plate 11, which also transmits the pressing pressure. Heat transfer from the indirectly heated steel belt 12 heats the surface or surface side of the pressure pad to a degree that the adhesive in each surface layer 2 or at least one surface layer begins to cure. The curing process is schematically shown as a black line that thickens along the transport direction as part of the pressure pad 1. At the outlet of the twin-belt press, the pressure pad 1 expands because the compressed intermediate layer 3 does not yet have cured adhesive, and the material of the intermediate layer 3 has been elastically compressed. The cover layers 2 are at least partially cured to a degree that allows them to permeate through fluids or ambient air, but retain their optional compressed shape. A pad 1 with at least a partially cured cover layer 2 and an uncured intermediate layer 3 is conveyed to an injection press 20, where the pad 1 is selectively compressed and reformed, and subjected to a fluid 5 during the injection press process. The fluid 5 ensures that the required curing temperature or other threshold for curing the intermediate layer 3 is reached. Along the length of the injection press 20, the increasing curing in the transport direction 8 is indicated by increasingly thicker shading lines, eventually merging into a continuous black material plate 4.

[0119] Referring to the directional arrow of fluid 5, it should be noted that the introduction of fluid 5 is shown in a simplified process. The introduction and / or discharge can be carried out alternately, alternately, in pulses, or in other variations during the evaporation process of the pressure pad upstream of the dual-belt press in a pre-press or similar equipment, and should be substantially known from the prior art.

[0120] Figure 2 Another preferred exemplary embodiment of the invention is shown. Here, the decompression region 17 between the dual-belt press 10 and the injection press 20, as well as the compression region 18 and the curing region 19 within the injection press 20, are shown in enlarged view.

[0121] After the dual-belt press 10, although the cover layer 2 is almost completely cured, the volume of the pressure pad 1 will (typically) increase due to the elastic restoring force in the intermediate layer 3. Simultaneously, ambient air will flow into the pressure pad 1 or the intermediate layer 3, optionally providing a cooling effect. This can be mitigated by employing pressing countermeasures such as slippers or rollers. However, it is preferred that the area around the pressure pad 1 in the decompression zone 17 is supplied with a correspondingly heated fluid, a different fluid, or preferably the same fluid 5 as in the injection press 20. By expanding, the pressure pad 1 absorbs hot air from the environment or the temperature-controlled fluid 5, and is heated rather than cooled in the cover layer 2 and / or the intermediate layer 3. Subsequently, the pressure pad 1 is recompressed or conveyed to the injection press 20, where it is compressed in the compression zone 18. The fluid 5 may be injected into the pressure pad again or for the first time, but preferably, a suitable compression unit 27 ensures the required compression pressure and, optionally, specifically absorbs or even removes excess pressure during venting of the pressure pad.

[0122] Particularly preferred is that the fluid is introduced through the compression unit 27 on one side and discharged on the other side of the surface. The compression unit may also be provided with an injection plate 21 or a calender 25 with rotating rollers that can introduce or draw / absorb fluid 5 in the direction of the pressure pad 1. For this purpose, the rollers are provided with openings on their circumference, wherein the rollers are covered by a plate on their circumference, and the plate has openings only in the direction of the pressure pad 1.

[0123] Alternatively or cumulatively, a frame or chamber 9 or shell may be arranged, preferably enclosing the end of the dual-belt press and the beginning of the injection press 10 or covering the decompression zone 17. For best visual effect, Figure 2 The chamber is clearly magnified and shown in the image. Alternatively, a tunnel can be provided here through which the pressure pad 1 is fed, and the tunnel is flushed by or will be flushed by fluid, which is absorbed by the pressure pad or intermediate layer 3 due to the increased volume in the decompression zone 17. The fluid can also be absorbed or supported by the narrow side 1439 of the pressure pad.

[0124] List of reference numerals in Figure 1439:

[0125] 1. Pressure pad

[0126] 2. Covering layer

[0127] 3. Intermediate layer

[0128] 4. Material board

[0129] 5. Fluid

[0130] 6. Pre-compressor

[0131] 7. Discharge container

[0132] 8. Transportation direction

[0133] 9. Chamber

[0134] 10. Double-belt press

[0135] 11. Heating plate

[0136] 12. Steel strip

[0137] 13. Roller Circulation System

[0138] 14. Deflecting roller

[0139] 15. Anti-caking agent application area

[0140] 16. Additive application section

[0141] 17. Decompression Zone

[0142] 18. Compression area

[0143] 19. Cured Area

[0144] 20. Injection molding machine

[0145] 21. Injection plate

[0146] 22. with

[0147] 23. Cleaning Unit

[0148] 24. Drive roller

[0149] 25. Calendering machine

[0150] 26. Deflection roller

[0151] 27. Compression Unit

[0152] 28. Steel strip

[0153] 29. Cooling plate

[0154] 30. Calibrate the press.

Claims

1. A method for continuously producing a material sheet from at least one material, said material being dispersed to form a flat pad and mixed with at least one adhesive capable of curing by heat and / or pressure, wherein said pad is capable of being dispersed as one or more horizontally layered pads, characterized in that, The pressure pad (1) is compressed in a double-belt press (10) having a steel belt (12) at a higher temperature than the pressure pad (1) and heated by heat conduction, wherein at least one cover layer (2) resting on the steel belt (12) is heated to a temperature higher than the curing temperature of the adhesive and the cover layer is at least partially cured. In this process, the uncured portion of the pressure pad (1), particularly the uncured intermediate layer (3), is heated to a temperature higher than the curing temperature of the adhesive and cured in a downstream injection press (20) by introducing a temperature-controlled fluid (5). The fluid (5) is introduced or passes through the pressure pad (1) through one or two covering layers (2).

2. The method as described in claim 1, characterized in that, Hot air, steam, preferably superheated steam, or a steam-air mixture is used as the temperature-controlled fluid (5).

3. The method as described in any one or more of the preceding claims, characterized in that, In the case of unsaturated air or steam-air mixture, the dew point is set such that the moisture contained in the fluid (5) condenses in the pad (1) only after entering the cover layer (2) or after passing through the cover layer (2).

4. The method as described in any one or more of the preceding claims, characterized in that, The intermediate layer (3) is brought to a suitable limit temperature and / or water content for curing the adhesive, preferably until the material plate emerges from the injection press (20).

5. The method as described in any one or more of the preceding claims, characterized in that, In the dual-belt press (10), a pressing pressure greater than 2 N / mm² is applied to the pressure pad (1), and preferably the pressing pressure does not exceed 6 N / mm².

6. The method as described in any one or more of the preceding claims, characterized in that, After leaving the dual-belt press (10), the thickness of the cured cover layer (2) is greater than 1 mm, preferably greater than 2 mm, and most preferably between 3 mm and 4 mm.

7. The method as described in any one or more of the preceding claims, characterized in that, Apply the hardener and / or liquid for the adhesive to the surface side of the pad (1), or apply the anti-caking agent to the steel strip (12) and / or the surface side of the pad (1).

8. The method as claimed in the preceding claims, characterized in that, After the pressure pad (1) has emerged from the dual-belt press (10), a non-destructive testing method is preferably used to determine the thickness of the cured cover layer (2), and most preferably, this value is used in a control or regulation system to adjust the thickness of the dual-belt press (10) or the cover layer (2).

9. The method as described in any one or more of the preceding claims, characterized in that, In the injection press (20), the pressure pad (1) is subjected to a surface pressure of less than 1 N / mm², preferably less than 0.6 N / mm², and very particularly preferably less than 0.5 N / mm².

10. The method as described in any one or more of the preceding claims, characterized in that, A flat injection plate (21) and / or a perforated roller with a cover is used to introduce the fluid (5) into the pressure pad (1), the cover being for an area not facing the pressure pad (1) and having openings for guiding and discharging the fluid.

11. The method as described in any one or more of the preceding claims, characterized in that, The fluid is introduced into the pressure pad (1) and / or emerges from the injection plate (21) at a pressure greater than 0.5 bar, preferably about 1.5 bar, and most preferably greater than 2 bar.

12. The method as described in any one or more of the preceding claims, characterized in that, The pressure pad (2) is guided through the injection press (20) by at least one permeable strip (22), the permeable strip (22) resting on a surface side for the passage of the fluid (5), wherein the strip (22) is preferably designed as a perforated metal strip or plastic strip, woven strip or chainmail strip.

13. The method as described in any one or more of the preceding claims, characterized in that, The belt (22) together with the pressure pad (1) is compressed in the injection press (20) upstream of the injection press (20) along the transport direction by a compression unit (27) or a calender (25) and / or is thrust in the transport direction (8), preferably by a calender (25) or a drive roller (24).

14. The method as described in any one or more of the preceding claims, characterized in that, After the intermediate layer (3) has cured, the material plate (4) is compressed and / or held to nominal size between two steel strips (28) in a calibrated press (30), preferably using a pressure of less than 2.5 N / mm².

15. The method as described in any one or more of the preceding claims, characterized in that, The covering layer (2) of the material plate (4) is smoothed, heated and / or cooled in the calibration press (30).

16. The method as described in any one or more of the preceding claims, characterized in that, Waste heat removed from the calibration press (30) due to the cooling process is reused, preferably in a heat pump, heat exchanger or other cryogenic equipment, wherein the waste heat is particularly preferably used for components of equipment located upstream of the calibration press (30) in the transport direction (8).

17. The method as described in any one or more of the preceding claims, characterized in that, The nominal thickness of the produced material board (4) is greater than 8mm, preferably greater than 30mm, and most preferably greater than 60mm. Among these, it is preferable to produce a solid material board with a thickness of up to 80mm.

18. The method as described in any one or more of the preceding claims, characterized in that, After the injection press (20), the uncured pressure pad (1) is discarded in the discharge container (7).

19. The method as described in any one or more of the preceding claims, characterized in that, The pad (1) is pre-compressed in the pre-press (6) to degas before entering the double belt press (10), preferably degassing there through at least one air-permeable fabric belt, and most preferably without temperature control.

20. The method as described in any one or more of the preceding claims, characterized in that, The material plate (4) cured in or emerging from the injection press (20) is subjected to a traction force along the production direction, preferably applied by the drive roller (24) of the injection press (20), by the calibration press (30), or by a separate calender (25).

21. The method as described in any one or more of the preceding claims, characterized in that, The production speed or the speed of each equipment component, preferably the dual-belt press (10), injection press (20) and / or calibration press (30), is controlled or regulated in a master-slave system by a control or regulation device, wherein the injection press (20) or its production speed is preferably used as a master variable or reference variable.

22. The method as described in any one or more of the preceding claims, characterized in that, Using single or multiple layers, preferably three or five layers of pads (1), is suitable for producing MDF, HDF, particleboard, OSB (shaving board), and mixed boards made of fibers and chips, wherein the fibers are preferably arranged in the outer layer or in the insulation board.

23. The method as described in any one or more of the preceding claims, characterized in that, At least in proportion, aminophenol-based adhesives, methylene diphenyl isocyanate (MDI), polymeric methylene diphenyl isocyanate (pMDI), urea-formaldehyde resin (UF), melamine-reinforced urea-formaldehyde resin (MUF), melamine-formaldehyde resin (MF), bio-based resins, preferably containing tannins of mixed polymers, plant and / or animal proteins, lignin containing mixed polymers, carbohydrate-containing adhesives, PVA, acrylic and / or epoxy resins can be used as curable adhesives in the pad (1).

24. The method as described in any one or more of the preceding claims, characterized in that, The pressure pad (1) or uncured intermediate layer (3) is inflated or rebounded in a depressurization zone (17) after leaving the dual-belt press (10), wherein the pressure pad (1) is available with temperature-controlled fluid (5) on at least one surface side and / or narrow side to bind to the pressure pad (1).

25. The method as described in any one or more of the preceding claims, characterized in that, The pressure pad (1) is compressed in the compression zone (18) after the dual-belt press (10), preferably on the inlet side of the injection press (20). The temperature-controlled fluid (5) of the pressure pad is preferably injected on at least one surface side of the compression region (18) and / or passively picked up or extracted on one surface side, most preferably on the opposite surface side.

26. The method as described in any one or more of the preceding claims, characterized in that, The pad material includes pure lignocellulosic materials and / or mixtures of lignocellulosic materials, such as natural wood, recycled wood, woody plants, waste wood, plant residues and / or annual plants, and preferably can be supplemented with filler materials.

27. An apparatus for continuously producing a material sheet from at least one material, said material being dispersed to form a flat pad formed by pressing the material, and mixed with at least one adhesive capable of curing by heat and / or pressure, wherein said pad can be dispersed as one or more horizontally layered pads, characterized in that, A double-belt press (10) is arranged in the transport direction (8) of the pad (1), the double-belt press having two infinitely circulating steel belts (12) for compressing and / or heating the pad (1) and for at least partially curing the cover layer (2) resting on the steel belts (12) by heating to a temperature higher than that of the adhesive, and an injection press (20) is arranged downstream of the double-belt press (10), the injection press having at least one means for injecting a temperature-controlled fluid (5) into one of the surface sides of the pad (1) for temperature-controlled curing of the uncured portion of the pad or intermediate layer (3).

28. The device as claimed in the preceding claims, characterized in that, An injection plate (21) or injection nozzle is arranged as a device for injecting a temperature-controlled fluid (5), preferably having an opening for providing preferably heated air, steam, superheated steam and / or steam-air mixture over a large area.

29. The device as claimed in any of the preceding claims, characterized in that, An anti-caking agent applicator (15) for applying anti-caking agent to the steel belt (12) or pressure pad (1) of the dual belt press (10) and / or an additive applicator (16) for applying additives and / or water to the pressure pad (1) are provided upstream of the dual belt press (10).

30. The device as claimed in any of the preceding claims, characterized in that, One or two infinitely looping belts (22) are arranged in the injection press (20), preferably perforated metal or plastic belts, woven belts or chainmail belts.

31. The device as claimed in any of the preceding claims, characterized in that, The compression unit (27) and / or the calender (25) are arranged in or near the injection press (20).

32. The device as claimed in any of the preceding claims, characterized in that, The calibration press (30) and / or the discharge container (7) are arranged downstream of the injection press (20) and / or the discharge container (7) is arranged downstream of the calibration press (30).

33. The device as claimed in any of the preceding claims, characterized in that, The calibration press (30) is provided with a heating and / or cooling system for the pad or plate, and is preferably operatively connected to a cryogenic device for recovering waste heat from the material plate (4), and preferably to a component of a heat exchanger, heat pump and / or device upstream of the calibration press (30).

34. The device as claimed in any of the preceding claims, characterized in that, A decompression zone (17) having a chamber (9), a tunnel, a housing and / or an injection plate is arranged between the dual-belt press (10) and the injection press (20) to provide the pressure pad (1) with a volume-increased, temperature-controlled fluid (5).

35. A material plate, said material plate preferably produced by the method according to any one or more of the preceding method claims and / or produced in the apparatus according to any one or more of the preceding apparatus claims.

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