Method and apparatus for producing a decorative wall or floor panel

Abstract

The invention relates to a method for producing a decorative wall or floor panel, having the following method steps: a) providing a molten polymer block; b) extruding a molten polymer mass through a nozzle (5); c) final shaping of the molten polymer mass by means of an assembly of a plurality of rotatable rollers (6, 7) to form the plate-like carrier material (9), in which individual rollers (6, 7) are arranged one above or behind the other and each individual roller (6, 7) is aligned with an adjacent roller (6, 7). The individual rollers (6, 7) form at least one final shaping nip through which the molten polymer mass (9) passes, and wherein the height of the final shaping nip can be variably adjusted during production by means of a horizontal and / or vertical movement of the individual rollers (6, 7); d) applying a decorative pattern simulating a decorative template to the at least one sub-region of the at least partially final shaped carrier material, and e) applying a protective coating to the at least one sub-region of the decoration.

Description

Methods and apparatus for producing decorative wall or floor panels

[0001] This application is a divisional application of application number 202080082383.5, filed on September 25, 2020, entitled "Method and apparatus for producing decorative wall or floor panels". Technical Field

[0002] This invention relates to a method for producing decorative wall or floor panels, comprising the following steps: a) providing a molten polymer block; b) extruding the molten polymer block by a die; c) final shaping the molten polymer block into a sheet-like carrier by an assembly of a plurality of rotatable rollers, wherein the rollers are positioned one above or behind another, and each individual roller forms at least one final shaping gap with an adjacent roller through which the molten polymer block passes, wherein the height of the final shaping gap can be variably adjusted during production by the horizontal and / or vertical movement of the individual rollers; d) applying a decoration that mimics a decorative template to at least one sub-region of at least partially finalized carrier; and e) applying a protective coating to at least one sub-region of the decoration.

[0003] Another object of the present invention is to provide an apparatus for producing decorative wall or floor panels, and wall or floor panels produced according to the methods described above. Background Technology

[0004] Decorative panels are known in themselves, for example, for use in interior design as floor or wall coverings. The term "wall panel" is also understood to refer to a panel suitable for ceiling cladding. The panel typically comprises a carrier or core made of a solid material (e.g., wood), with a decorative layer and a top layer disposed on at least one side, and optionally with additional layers, such as a wear-resistant layer disposed between the decorative layer and the top layer. The decorative layer is typically a printed sheet impregnated with resin. The top layer and other layers are also typically made of resin.

[0005] Methods for producing panels typically involve multiple process steps. For example, a "cake" of pellets can be applied to the lower belt of a press using a feeder. During production, this cake is typically fed into a hot belt press with steel and / or PTFE (Teflon) belts, where the pellets are heated and melted. Simultaneously, the material can be pressed and shaped into a carrier form. Subsequently, controlled cooling results in the solidification or crystallization of the carrier material, where most of the waste heat remains unused because the available temperature difference caused by controlled cooling is too small for any other application. The heat transfer process in this belt press is achieved from above and below through contact with the press. Furthermore, for cooling, it is disadvantageous that heat must pass through the glass fiber reinforced PTFE belt. Only in this way does heat conduction occur by transferring heat to the pellet filler or carrier material. These physical processes are very slow because the pellet cake initially still contains air from the pellet filler, which, from the perspective of product physical properties, may only be slowly expelled from the carrier. To achieve acceptable belt speeds in production, high temperature gradients must be applied for cooling, resulting in considerable waste heat loss.

[0006] For example, EP3140129 B1 describes a reasonable method for producing decorative wall or floor panels. This method includes the following steps: a) providing a castable carrier material, particularly granules; b) placing the carrier material between two belt conveyors; c) molding the carrier material under temperature to form a mesh carrier; d) compressing the carrier; e) processing the carrier under pressure using a twin-belt press, wherein the carrier is cooled within or upstream of the twin-belt press; f) optionally further cooling the carrier; g) optionally applying a decorative undercoat to at least one sub-area of ​​the carrier; h) applying a decoration mimicking a decorative template to at least one sub-area of ​​the carrier; i) applying a protective coating to at least one sub-area of ​​the decoration; j) optionally constructing the protective coating to introduce holes and / or constructing edge regions of the carrier to form connecting elements; and k) optionally treating the carrier prior to any of the above method steps to perform electrostatic discharge.

[0007] The manufacturing of the panel offers potential for further improvement. Summary of the Invention

[0008] Therefore, the object of the present invention is to provide an improved method for producing decorative wall or floor panels.

[0009] This objective is achieved by the method according to claim 1 and the device according to claim 9; for wall or floor panels, this objective is achieved by the panel according to claim 10.

[0010] Therefore, the present invention provides a method for producing decorative wall or floor panels, comprising the following steps: a) providing a molten polymer block; b) extruding the molten polymer block by a die; c) final shaping the molten polymer block to form a sheet-like carrier by an assembly of a plurality of rotatable rollers, wherein the rollers are positioned one above the other or one behind the other, and each individual roller forms at least one final shaping gap with an adjacent roller through which the molten polymer block passes, wherein the height of the final shaping gap is variably adjustable by horizontal and / or vertical movement of the rollers during production; d) applying a decoration mimicking a decorative template to at least one sub-region of the at least partially finalized carrier; and e) applying a protective coating to at least the sub-region of the decoration.

[0011] Surprisingly, the methods described above have been found to improve the production of wall or floor panels. By combining the above method steps, high-quality panels with improved decorative properties can be obtained in a very short processing time. In particular, due to the final shaping step according to the invention, the panel has a particularly flat carrier surface, and high-quality decoration can be applied to this carrier surface particularly effectively. Without being limited by theory, the decoration applied according to the invention exhibits particularly high-quality optical properties due to the particularly smooth and defect-free surface of the carrier material. The above methods also enable high throughput at high roll speeds and reduce the proportion of non-uniform panels. In particular, according to the invention, incorporating the final shaping step of the rollers into the production process can reduce the percentage of air inclusions at the panel surface, thanks to improved removal of air present in the carrier and improved removal of air from the roll gaps. In addition to the direct process advantages, the flexible process of using individually controllable rollers can also reduce shop setup and break-in time, resulting in higher processing efficiency. Furthermore, a greater proportion of processing energy can be recovered through the final shaping-grading sub-step according to the invention, which generally contributes to lower carbon dioxide (CO2) emissions in the process used, and thus also contributes to lower carbon dioxide (CO2) emissions in the produced panels.

[0012] The method according to the invention is a method for producing decorative wall or floor panels. In the context of this invention, the term "decorative wall or floor panel" or "decorative panel" specifically refers to decorative wall, ceiling, or floor panels applied to a carrier sheet and mimicking decorative templates. Here, decorative panels are used in various ways in the field of interior design of rooms and as decorative cladding of buildings, such as for exhibition booth structures. One of the most common applications of decorative panels is as floor coverings. Decorative panels typically have decorations designed to mimic natural materials.

[0013] Examples of this imitation of natural materials or decorative templates include various wood species such as maple, oak, birch, cherry, ash, walnut, chestnut, wenge, or even exotic woods such as panga-panga, mahogany, bamboo, and bubinga. Furthermore, natural materials such as stone or ceramics can also be replicated.

[0014] Therefore, in the sense of this invention, the term "decorative template" can be understood to specifically mean that the natural material or at least its surface will be decorated to imitate or simulate.

[0015] Method step a) includes providing a molten polymer block. The molten polymer block exhibits at least partially the properties of a flowable viscous liquid and can be obtained, for example, by a heat treatment step of a polymer that is typically in particulate form. Here, the molten polymer block may consist of only one homogeneous polymer block or of several polymer blocks (feed blocks) that are mixed with each other or stacked on top of each other in a defined form. “Particles” or “particulate material” can be understood to mean a solid or aggregate of solids comprising a plurality of solid particles such as fine particles or spheres or composed thereof. By way of example, but not exhaustive, particulate or powdered materials, or suitable recyclable materials existing as abrasive materials, may be mentioned here.

[0016] Polymer blocks or granules may comprise plastic-based carrier materials, inorganic filler-based compounds, or wood-based plastic composite (WPC) materials. For example, molten polymer blocks, and therefore carrier sheets, may be formed substantially of thermoplastic, elastomeric, or thermosetting plastics. Furthermore, recyclable materials made from the aforementioned materials can be used within the framework of the method according to the invention. Here, preferably, thermoplastics, such in particular polyvinyl chloride, polyolefins (e.g., polyethylene (PE), polypropylene (PP)), polyamide (PA), polyurethane (PU), polystyrene (PS), acrylonitrile butadiene styrene (ABS), polymethyl methacrylate (PMMA), polycarbonate (PC), polyethylene terephthalate (PET), polyetheretherketone (PEEK), or mixtures or copolymers thereof, may be used as molten polymer blocks. For example, plasticizers may be provided independently of the carrier's base material, and their presence may range, for example, from ≥0 wt.% to ≤20 wt.%, particularly ≤10 wt.%, preferably ≤7 wt.%, for example, from ≥5 wt.% to ≤10 wt.%. Suitable plasticizers include, for example, those sold by BASF under the trade name "Dinsch". Additionally, copolymers such as acrylates or methacrylates, or blends with thermoplastic elastomers (TPEs), can serve as alternatives to conventional plasticizers.

[0017] To produce molten polymer blocks, one or more so-called dry blends, such as dry plastic powder with additives, can be melted. Additives may include, for example, "fibrous materials," such as paper and nonwovens based on plant, animal, mineral, or even man-made fibers or paperboard. Examples include fibrous materials made from plant fibers, and sheets made from biomass, in addition to paper and nonwovens made from cellulose fibers, such as straw, corn stalks, bamboo, leaves, algae extracts, cotton, or oil palm fibers. Examples of animal fiber materials include keratin-based materials, such as wool or horsehair. Examples of mineral fiber materials include those made from mineral wool or glass wool.

[0018] These materials can be provided in step a), for example by a screw extruder, where the polymer material or dry blend is melted by pressure, temperature and shear force, optionally homogenized and transferred to step b).

[0019] In step b), the molten polymer block is extruded through a die. The molten and plasticized polymer block is forced through the die by pressure, wherein suitably, a portion of the final product geometry has been predetermined by selecting the die geometry. For panels, the selection of a slot die or a wide-slot die has proven particularly suitable, with a slot width to slot height ratio greater than about 4:1 (width:height), preferably greater than 10:1, and more preferably greater than 20:1. Particularly for panels according to the invention, this relatively wide and narrow die geometry allows for pre-forming most of the carrier structure, making it possible to maintain minimal subsequent effort required for final shaping of the extruded polymer block. In particular, wide-slot dies may be advantageous with means for adjusting the die roll gap. For example, these means can be used to make the edge regions of the extruded flat strands extremely flat, thereby allowing for the formation of connections between different panels in these edge regions that are flatter than the average panel thickness in further method steps, without requiring significant final shaping work.

[0020] In step c), while forming the sheet-like carrier, the molten polymer block is final-shaped by an assembly of multiple rotatable rollers, wherein the rollers are positioned one above or one behind the other, and each individual roller forms at least one final-shaping gap with the adjacent roller through which the molten polymer block passes. The height of the final-shaping gap can be variably adjusted by the horizontal or vertical movement of the individual rollers during production. Compared to existing technologies, the forming and final shaping of the panel are not performed using a flatbed press, but rather using rollers. The molten polymer block passes through the gap between the rollers formed by the roller assembly, and due to the mechanical stress in the gap, the polymer block is compressed and reaches the desired thickness. In addition to the mechanical force applied by the rollers, the polymer block can also be cooled simultaneously. This can be done by the rollers or by other cooling devices, such as by blowing air. The fact that effective final shaping can be achieved through the roller assembly and through the gap is surprising, as the viscoelastic properties of the molten polymer block are suitable for use with presses having a large surface area. Compared to a press, the smaller active final setting surface in the roll gap should mean that, due to the rheological properties of the polymer block, such as thixotropic properties, only insufficient final setting is achieved at the small final setting surface. Surprisingly, however, this is not the case, thus efficient and time-saving production can be ensured by using an assembly of multiple rolls. Multiple rolls in this document refer to more than four rolls, such as five rolls, where the multiple rolls form at least three or four separate roll gaps. The roll gaps are preferably arranged one after another, separated by the rolls. In particular, according to the invention, it is also provided that the final setting of the carrier is performed solely by passing the molten carrier material through the roll gaps. Here, according to the invention, the method can also completely abandon the use of sheet-like pressing equipment, such as a belt press. It is also possible to determine the final setting of the carrier solely by using rolls arranged directly and continuously one after another at a single location in the equipment. In this case, the division of the roll assembly, for example, first two roll gaps, then, for example, a cooling section, and then one or two roll gaps, is not according to the invention. According to the present invention, the final shaping can be performed directly after the carrier material is extruded, and further important final shaping or leveling steps can be omitted.

[0021] During manufacturing, the height of the final shaping roll gap can be variably adjusted by moving the individual rollers horizontally or vertically. This means that changes in the position of each roller also alter the roll gap size of one or more gaps formed by adjacent rollers. Thus, the roll gap size, and therefore the carrier height, can be affected by the distance between the rollers. Furthermore, the pull angle or incident angle of the molten polymer material from or onto the rollers can be altered by the relative height of the rollers relative to each other, which can result in different mechanical forces, potentially different cooling performance and area, and possible air entrainment between the rollers and the polymer. If the rollers can change their X and / or Y positions as the polymer material passes through them, then the rollers are variably adjustable during manufacturing. During manufacturing, the individual roll gaps can be controlled either isobarically or isochorically. The former operating mode results in mechanical forces on the polymer carrier material in the roll gap, while the latter operating mode is based on a constant thickness of the roll gap between the two rollers. Therefore, in the former operating mode, the position of the rollers is dynamically adjusted, while in the latter operating mode, the position of the rollers relative to each other remains relatively constant.

[0022] It is particularly advantageous to set different final shaping gaps between several or all the rollers. This can counteract fluctuations in carrier thickness that occur during production, as well as the potentially non-uniform cooling performance of the individual rollers. Each roller can simply operate together or support the transport of the film, which is why it is also possible to provide rollers that can be driven individually or together. Depending on the roller's positioning, the carrier material can pass through the roller in a quasi-wavy line, thus contacting one side of the continuous roller once and the other side once. To ensure that the effect of the contact area between the roller and the carrier surface is substantially the same on both sides of the carrier, it can be provided that the diameters of the main roller and the downstream roller are selected such that the contact surface between the carrier and the roller is substantially the same on both sides of the carrier. When passing through the respective roller, only one side of the extrudate is cooled each time, which can potentially create stress in the sheet. To counteract this non-uniform cooling forming, for example, the rear side can be actively cooled by introducing cold air (e.g., an air knife) to achieve a more uniform cooling effect on the carrier.

[0023] Since cooling behavior can vary with the width of the extrudate, and to counteract the necking effect, heat can be utilized in the edge regions on opposite sides. For example, an IR emitter can be used for this purpose. Other measures for uniformly cooling the molded polymer block can be a vacuum chamber that ensures the polymer melt is applied to the rollers without air, or so-called edge pin connections, where the edge regions are electrostatically fixed to the rollers.

[0024] In step d), the decoration of the replica decorative template is applied to at least a sub-region of the carrier, which is at least partially finalized. Thus, the application of the decorative template can be performed after the finalized carrier passes through the roller assembly or before it passes through the last finalized roller clamp. By the method according to the invention, the carrier not only has a particularly smooth surface with low roughness but also a surface with particularly low air inclusions. These two factors can contribute to a particularly reproducible and high-quality decorative carrier final product. Unrestricted by theory, air in the carrier can escape better compared to a flat press due to the relatively small volume in the gap between the roller pairs. This can result in a carrier and carrier surface with particularly low air inclusions. By introducing a second white polymer melt on the upper side of the molten and extruded polymer, a smooth, non-porous printed lower layer can be applied, unlike prior art solutions which do not require a coating of non-polymer-based thermosetting materials. Here, it is advantageous that it consists of a thermoplastic polymer matrix that is almost identical to the carrier sheet. The latter is highly advantageous for efficient recycling.

[0025] Furthermore, the decoration, which replicates the decorative template, is applied to at least a sub-region of the carrier. Here, the decoration can be applied, for example, by so-called direct printing. In the context of this invention, the term "direct printing" should be understood as applying the decoration directly to the carrier of the panel or to a non-printable fibrous material layer applied to the carrier or to a decorative sub-layer. Different printing techniques can be used, such as flexographic printing, offset printing, or screen printing. In particular, inkjet or laser printing processes can be used as digital printing techniques.

[0026] For example, in order to imitate or replicate a three-dimensional decorative template in a particularly fine and highly accurate manner, the decoration can be applied in the same manner as the original after passing through the roller assembly. In particular, three-dimensional decorative data can be provided by three-dimensional scanning of the decorative template using electromagnetic radiation, for example, by a 3D scanner. Here, based on the provided three-dimensional decorative data, multiple decorative layers with at least partially different surface applications can be applied sequentially.

[0027] Furthermore, the decorative layer can be formed from, in particular, radiation-curable paints and / or inks. For example, UV-curable paints or inks can be used. In this embodiment, particularly fine and matching replication of the decorative template can be achieved. On the one hand, synchronized holes can be achieved with high precision in this way without providing further measures. Here, synchronized holes can be, in particular, holes or another type of structure that are spatially precisely set at positions optically represented by tactile structures corresponding to optical decorative features. In this embodiment, this is essentially automatic because the structural design is precisely generated by the pigments or inks. In addition, decorative templates such as those made of wood-based materials typically exhibit color impression variations not only along their width or length but also along their depth. In this embodiment, this color impression or color gradient can also be replicated with particularly fine detail, which also makes the overall appearance of the panel more consistent. Therefore, particularly rapid curing can be achieved, especially when the paint or ink used is radiation-curable, thereby allowing multiple layers to be quickly superimposed on each other, which also makes the entire process feasible in a shorter time and therefore particularly cost-effective.

[0028] In the context of this invention, the term radiation-curable coating should be understood as a composition comprising binders and / or fillers and colored pigments, which can be induced at least partially polymerized by electromagnetic radiation of a suitable wavelength, such as UV radiation or electron radiation.

[0029] Therefore, in the sense of this invention, the term radiation-curable ink should be understood to refer to a substantially filler-free composition containing colored pigments that can be at least partially polymerized by electromagnetic radiation of a suitable wavelength, such as UV radiation or electronic radiation.

[0030] Here, the thickness of the decorative layer can range from ≥5μm to ≤10μm.

[0031] In terms of color and / or structure, in addition to positive images, corresponding negative images of decorative stencils can also be applied. Specifically, for example, as is known from positive or negative staining of wood-based materials, the color impression of texture can be reversed using digital data, thus obtaining negative results regarding color or, in particular, lighter and darker areas. This is possible not only for color impressions but also for the applied structure, thus enabling the achievement of negative effects in structural design. Such effects can also be easily integrated into production processes based on digital 3D data without the need for lead time or conversion.

[0032] In step e), a protective coating is applied to at least a sub-area of ​​the decoration. This protective layer, applied to protect the decoration, can be applied as an abrasion layer or top layer in subsequent method steps, and particularly protects the decoration from wear or damage caused by dirt, moisture, or mechanical effects such as abrasion. For example, the abrasion layer and / or top layer can be laid on a printing carrier as, for example, a melamine-based pre-production overlay and bonded thereto by pressure and / or heat. To form the abrasion layer and / or top layer, a radiation-curable composition, such as a radiation-curable coating like an acrylic coating, is also preferably applied. Here, the abrasion layer can be specified to consist of hard materials such as titanium nitride, titanium carbide, silicon nitride, boron carbide, tungsten carbide, tantalum carbide, alumina (corundum), zirconium oxide, or mixtures thereof to improve the abrasion resistance of the layer. In this regard, the coating can be applied, for example, by a roller such as a rubber roller or by a casting device.

[0033] In addition, the top coating can be partially cured first, followed by a final coating and final curing with urethane acrylate, for example, using a gallium emitter.

[0034] Furthermore, the top layer and / or wear-resistant layer may include means for reducing the static charge on the final laminate. For example, for this purpose, the top layer and / or wear-resistant layer may be provided to include compounds such as choline chloride. In this regard, the antistatic agent may be present, for example, in the top layer and / or the composition used to form the wear-resistant layer at concentrations of ≥0.1 wt.-% and ≤40.0 wt.-%, preferably ≥1.0 wt.-% and ≤30.0 wt.-%.

[0035] Similarly, a transparent abrasion-resistant layer of thermoplastic polymer is also suitable, which is laminated onto the decorative layer as a thin film mesh. Optionally, for sufficient adhesion, an adhesion promoter / primer is required, which is bonded to the decorative layer by radiation curing from above (“adhesive coating”) or by heat sealing (“thermal melt”). The thermoplastic abrasion-resistant layer further provides advantages for the recycling process of the entire structure. Surface structuring can be introduced very easily through structured sheets heated by a press or through structured rolls of a calender (these can also be done concurrently with the decoration).

[0036] It can also be configured to introduce structures, particularly surface structures matching the decoration, into the protective layer or wear layer and top layer respectively through introduction holes. Here, it can be configured that the carrier sheet already has a structured portion, and the alignment of the printing tool for applying the decoration and the carrier sheet relative to each other is performed according to the structured portion of the carrier sheet detected by optical methods. For the alignment of the printing tool and the carrier sheet relative to each other, it can be configured that the relative movement required for alignment between the printing tool and the carrier sheet can be achieved by moving the carrier sheet or by moving the printing tool. Furthermore, it can be configured that the structuring of the decorative panel is performed after the application of the top layer and / or wear layer. For this purpose, it is preferable to apply a curable composition as the top layer and / or wear layer, and the curing process is carried out only to the point where the top layer and / or wear layer is only partially cured. During or after the final shaping step, the desired surface structure is embossed into the thus partially cured layer using a suitable tool, such as a hard metal structural roller or embossing die. In this case, embossing is performed according to the decoration applied. To ensure a sufficient match between the structure to be introduced and the decoration, it can be configured that the carrier sheet and the embossing tool can be aligned relative to each other through appropriate relative movement. After the desired structure is incorporated into the partially cured top layer and / or abrasion layer, the now structured top layer and / or abrasion layer is further cured. In another step, the decorated carrier sheet can then be divided into individual panels by a suitable mechanical process. This can be done, for example, by cutting the extruded strands at regular intervals or at regular time intervals. Preferably, this method step can produce cut panels of equal length.

[0037] In a preferred embodiment of this method, final shaping in step c) can be performed using at least one master roll pair, consisting of two rolls with large diameters and at least three final shaping rolls arranged sequentially with diameters smaller than those of the master roll pair. To obtain the most uniform surface structure possible for receiving decoration, it has proven particularly advantageous to apply mechanical force, and if necessary, thermal force to the carrier in a non-uniform manner using different roll sizes. This measure results in a particularly smooth carrier surface, which can be decorated particularly easily and reproducibly. Here, the main portion of the desired and necessary deformation can be achieved using a larger roll pair, while another smaller final shaping roll applies only less force to obtain a uniform final shaped product and delivers air out of the substrate in a controlled manner. This allows for high linear speeds while maintaining only slight thickness variations in the produced carrier. Roll diameters are dimensionally different if the corresponding diameters of the master rolls and final shaping rolls differ by at least 10%. For example, the above-described components result in the following roll gap assembly for molten polymer material: The molten polymer material is forced through the roll gaps between the master rolls and at least two roll gaps between at least three final shaping rolls. For example, the component may have a total of 8, preferably 6, and more preferably 4 final setting rollers. It has been found that this number of individual roller gaps is particularly suitable for obtaining decorative panels with improved surface and decorative properties.

[0038] In another embodiment of the method, the main roller pair H H The height of the final shaping roll gap can be related to the final shaping roll H. K The height difference between the final shaping roll gaps is greater than or equal to 10% and less than or equal to 50%. The aforementioned roll gap height ratio between the main roll and the final shaping roll has proven particularly suitable for obtaining a particularly smooth carrier surface and a carrier material with particularly low mechanical stress. The forces acting on the carrier can be determined collectively by this specification, thereby specifying a force distribution particularly suitable for the production of decorative panels for the roll assembly. This results in particularly advantageous performance regarding the presence of air inclusions and the occurrence of stress cracks in the carrier material. Furthermore, the distance of the applied mechanical force for forming the carrier relative to the location where the decoration is applied also appears to play an important role. In this regard, it has been found particularly suitable in the preferred embodiment that the height of the final shaping roll gap is greater than or equal to 10% and less than or equal to 50% of the height of the main roll gap. This allows for higher linear speeds without compromising the surface quality of the decorative panel.

[0039] In another aspect of the method, the height of the last and / or penultimate final shaping roll gap can be selected such that the carrier is compressed at its height by a coefficient less than or equal to 10% and greater than or equal to 3%. This compression ratio has proven particularly advantageous for obtaining exceptionally low air retention and a exceptionally smooth carrier surface. This ratio can be determined, for example, by measuring the substrate thickness before and after passing through the roll gap. Here, the desired compression ratio is adjusted by the shaping ratio of the final shaping roll gap height or also by the force applied to each roll gap.

[0040] In another preferred feature of the method, step d) may additionally include applying a decorative underlayer to at least one sub-region of the carrier prior to the application of the decoration. Simultaneously with, or shortly before, the application of the decorative layer, or even already in the roller assembly, additional optional layers, such as a decorative underlayer or primer layer, may be applied to the carrier. For example, it may be advantageous to apply these additional layers to the carrier upstream of the last roller, as improved adhesion of these additional layers to the carrier can be achieved through at least one mechanical treatment in an additional final shaping roller gap. Furthermore, the carrier can be pretreated by electrostatic discharge between or downstream of the roller assemblies. This can be particularly useful in preventing blurring during the application of the decoration. This is especially suitable for printing processes that apply decorative layers, as the electrostatic charge accumulating in the carrier to be printed during production causes paint or ink droplets to deflect along their path from the print head to the surface to be printed. The resulting inaccurate application of paint or ink leads to perceptible blurring of the printed image.

[0041] A possible electrostatic discharge device may include at least one roller or a single roller, brush, or flange, which are made of materials with a conductivity ≥1×3 Sm -1 It is made of a conductive material, forming a conductive contact with the carrier at least in the area of ​​the printed cell, and is connected to a mass potential. For example, the mass potential can be provided by grounding. Furthermore, the device for discharging static charge can be, for example, a device for generating corona discharge.

[0042] The decorative undercoat may include, for example, a first primer, particularly a primer for printing processes, for example, with a thickness of ≥10 μm to ≤60 μm. As a primer herein, a liquid radiation-curing mixture based on urethane or urethane acrylate may be used, optionally containing one or more of a photoinitiator, reactive diluent, UV stabilizer, rheology modifiers such as thickeners, free radical scavengers, leveling agents, defoamers or preservatives, pigments and / or colorants. For example, urethane acrylate may be present in the primer composition in the form of reactive oligomers or prepolymers. In the context of this invention, the terms "reactive oligomer" or "prepolymer" should be understood as compounds containing urethane acrylate units, which may optionally react to form radiation-induced urethane or urethane acrylate polymers upon the addition of a reactive binder or reactive diluent. Here, urethane acrylate in the context of this invention is a compound substantially composed of one or more aliphatic structural elements and urethane groups. Aliphatic structural elements include alkylene groups, preferably having 4 to 10 carbon atoms, and cycloalkylene groups, preferably having 6 to 20 carbon atoms. Both alkylene and cycloalkylene groups can be mono- or poly-substituted with C1-C4 alkyl groups, particularly methyl groups, and can contain one or more non-adjacent oxygen atoms. Aliphatic structural elements are optionally bonded to each other via quaternary or tertiary carbon atoms via urea, biuret, urea diketone, urethane, cyanurate, carbamate, ester, or amide groups, or via ether oxygen or amine nitrogen. Furthermore, polyurethane acrylates in the sense of this invention may also contain olefinically unsaturated structural elements. These are preferably vinyl or allyl groups, which can also be substituted with C1-C4 alkyl groups, particularly methyl groups, and they are particularly derived from α-β-olefinically unsaturated carboxylic acids or their amides. Particularly preferred olefinically unsaturated structural units are acryloyl and methacryloyl groups, such as acrylamide and methacrylamide, particularly acryloyloxy and methacryloyloxy. In the context of this invention, radiation-curable means that the primer composition can be induced to polymerize at least partially by electromagnetic radiation of a suitable wavelength, such as UV or electron radiation.

[0043] Using a radiation-curable primer based on polyurethane acrylate allows for the application of decorations immediately after application and, for example, radiation-induced curing of the primer layer via digital printing technology, in a particularly advantageous manner. In this case, the primer layer ensures good adhesion between the applied decoration and the primer-coated carrier surface. Here, polyurethane acrylate has the advantage of good adhesion to the carrier material and the decorative layer, i.e., the decorative paint or ink. This is especially due to the polymerization reaction that occurs in this type of polymer, where radiation-induced free radical polymerization of OH groups occurs on the one hand, and post-curing of the polymer occurs on the other hand through NCO groups. This results in an immediately non-sticky and further processable surface after radiation-induced curing, while the final properties of the primer layer are also affected by the NCO-based post-curing, providing a strong bond with the carrier material. Furthermore, the post-curing ensures sufficient layer stability even in less exposed or unexposed areas of the carrier. Thus, the method according to the invention can also be used particularly to reliably apply a primer layer to a pre-constructed carrier, i.e., a carrier whose surface already has a three-dimensional structure, thereby ensuring that the subsequently applied decoration is firmly bonded to the carrier.

[0044] In the method according to the invention, the primer is preferably applied via a rubber roller, a casting machine, or by spraying onto a carrier sheet passing through the roller assembly. The primer can also be applied downstream of the roller assembly but before the application of the finishing coat. Preferably, the amount of primer applied is ≥1 g / m². 2 And ≤100g / m 2 Preferred concentration: ≥10g / m 2 And ≤50g / m 2 Especially ≥20g / m 2 And ≤40g / m 2 After applying the primer to the substrate surface, irradiate it with a radiation source of appropriate wavelength.

[0045] In addition to using a primer, decorative applications can be made onto decorative paper that can be printed with corresponding decorations. This decoration can be provided, for example, by using a resin layer as an adhesive pre-applied to the substrate. This printed underlayer is suitable for flexographic printing, offset printing, and screen printing processes, and is particularly suitable for digital printing technologies such as inkjet or laser printing. For the application of the resin layer, it is preferable that the resin composition used includes at least one compound selected from melamine resin, formaldehyde resin, urea resin, phenolic resin, epoxy resin, unsaturated polyester resin, diallyl phthalate, or mixtures thereof as a resin component. For example, the amount of resin composition used is ≥5 g / m³. 2 and ≤40g / m 2 Preferred concentration: ≥10g / m 2 and ≤30g / m 2 In addition, it can have a weight of 30g / m³. 2 Up to ≤80g / m2 Preferred size ≥40g / m 2 Up to ≤70g / m 2 Paper or non-woven fabric is applied to sheet-like carriers.

[0046] In the framework of a preferred embodiment of the method, applying the decorative underlayer to at least a sub-region of the carrier in step d) can be performed upstream of the last roller of the roller assembly in step c). To form a particularly tight bond between the decorative underlayer and the carrier, it has been found particularly suitable that the final setting roller is used not only to set the carrier height but also to apply and mechanically fix the decorative underlayer. This measure enables a particularly efficient method, which, in particular, also accelerates the drying of the decorative underlayer, since the carrier has a higher temperature at that point in the method. Therefore, more mechanical parts can be saved, and temperature control during cooling can be optimized. For example, the total heat dissipated from the material can be reduced by utilizing the heat capacity of the decorative underlayer.

[0047] In another preferred embodiment of the method, in addition to the main roll pair, the roll assembly may include at least four additional final shaping rolls, wherein one of the roll gaps of the final shaping rolls is driven isobarically. Compared to an operating mode with a constant roll gap thickness between the final shaping rolls, it has proven particularly advantageous for the surface properties of the carrier that at least one of the roll gaps operates isobarically, i.e., acts on the carrier with a constant force. This allows for very fast processing times while maintaining the smoothest possible carrier surface. In the sense of the invention, isobaric operation means that, by controlling the roll gap, the force fluctuation acting on the carrier in the roll gap during carrier production is less than 10%, preferably less than 5%, and more preferably less than 2.5%. The force used to produce the carrier can be measured, for example, by force sensors in or on the rolls, or by one or more force sensors in the carrier material.

[0048] In a preferred aspect of the method, the master roll and the final shaping roll can be configured to be temperature-controlled, and the temperature-controlled surface area of ​​the final shaping roll can be greater than or equal to 1.1 to less than or equal to 2.5 times that of the master roll. In addition to the mechanical treatment of the molten polymer block, the roll assembly can also be used for the simultaneous heat treatment of the carrier. Heat treatment can, in principle, include partial heating or partial cooling of the carrier. Advantageously, the molten material is cooled at the roll surface by passing it through the rolls. This can be achieved, for example, by providing a supply device for a heat transfer medium, such as a coolant, internally on each roll. It is also advantageous that the surface temperature of each roll in the roll assembly can be controlled individually. This can contribute to a particularly reproducible and gentle forming and cooling process. The aforementioned ratio of cooling surfaces between the master roll and the final shaping roll has proven particularly suitable for obtaining decorative panels with particularly low mechanical stress and particularly little air inclusion. Without being bound by theory, higher quality decoration is achieved by heat dissipated in a controlled manner at each step, which is also proportional to the surface area of ​​the roll pair. Within this range, very high web speeds and particularly efficient removal of air inclusions from the carrier can also be achieved. Furthermore, the temperature of each roller can be selected based on the mechanical force applied to the carrier, and thus the cooling rate that can be obtained can also be selected. For example, a greater force caused by the high compression of the carrier material can be accompanied by a higher temperature gradient between the roller and the carrier material, thereby obtaining a carrier with lower overall mechanical stress.

[0049] Furthermore, according to the present invention, an apparatus for producing decorative wall or floor panels is provided, wherein the apparatus includes means for performing the method according to the invention. For the advantages of the apparatus according to the invention, reference is made to the advantages of the method according to the invention. A preferred embodiment of the apparatus may include a temperature-controlled screw extruder and a die with a variable forming groove. Furthermore, the apparatus may include temperature-controlled and, in particular, coolable rollers. During production, the individual rollers can move relative to each other in their positions, thus the size of the gap formed between the rollers can also be changed. Preferably, at least one larger pair of master rollers and multiple, preferably at least three, more preferably four, more preferably five, smaller final shaping rollers are available for forming the carrier and final shaping the carrier. The rollers can be configured to be individually adjustable in terms of their temperature. Downstream of the roller assembly, the apparatus according to the invention may further include means for applying additional layers, such as a decorative underlayer, a decorative layer, and / or abrasion protection layer. The means for applying these layers may be located downstream of the final shaping rollers. Preferably, the decoration is applied downstream of the roller assembly via a direct printing process. The application of a decorative protective coating can be performed, for example, by lamination under pressure, by brushing, or by applying a liquid or paste-like protective coating compound with a scraper. The equipment may also include additional means for final cooling of the carrier. It may also include additional means for recirculating heat dissipated from the carrier back into the product cycle. This can be accomplished, for example, via a heat exchanger. The recovered waste heat can be used, for example, for temperature control of the extruder. Furthermore, the equipment may include additional means for machining the carrier, such as special shaping for the carrier edges. Additionally, the equipment may include additional means for further dividing the extruded sheet into smaller panels of substantially equal length. This division or cutting can be performed, for example, by using a saw. For this purpose, a circular saw or band saw, for example, may be suitable. However, other physical methods, such as lasers, can also be used to divide the extruded and decorative panels into smaller panels.

[0050] Furthermore, according to the present invention, wall or floor panels produced by the method according to the present invention are provided. For the advantages of the wall and floor panels according to the present invention, reference is made specifically to the advantages of the method according to the present invention and the advantages of the apparatus according to the present invention. In particular, it should be noted that, by using the method according to the present invention, panels can be obtained at very high linear speeds, characterized by particularly smooth surfaces and low air content in the pores and pores at the panel surface. The number and size of surface defects caused by air can be significantly reduced. Temperature control and mechanical processing also result in a very low-stress carrier. Furthermore, the method and apparatus are suitable for processing various materials.

[0051] In a particularly advantageous manner, the carrier material may include or consist of a wood-polymer material (wood-plastic composite, WPC). Here, for example, wood and polymer may be suitable, present in a 40 / 60 to 70 / 30, e.g., 50 / 50 ratio, and the polymer component may be, for example, polypropylene, polyethylene, or a copolymer of two of the aforementioned materials. The advantage of such materials is that they can be formed into a carrier at low temperatures, e.g., in the range of ≥180°C to ≤200°C, in the methods described above, allowing for particularly efficient process control, e.g., exemplary linear speeds in the range of 6 m / min. For example, a WPC product with an exemplary product thickness of 4.1 mm and a 50 / 50 distribution of wood and polymer components can be obtained, enabling a particularly efficient production process.

[0052] In a preferred embodiment of the wall or floor panel, the panel may contain 50 wt.% to 100 wt.% of WPC or PVC material. Furthermore, it is particularly advantageous that the carrier material comprises or is composed of PVC-based material. This material can also be used advantageously for high-quality panels, for example, it can be used without problems in humid rooms. Moreover, PVC-based carrier materials are suitable for particularly efficient production processes, as a linear speed of 8 m / min is possible with an exemplary product thickness of 4.1 mm, enabling a particularly efficient production process. Furthermore, such a carrier also exhibits advantageous elasticity and water compatibility, which can lead to the aforementioned advantages.

[0053] In the case of both plastic-based and WPC-based panels, mineral fillers can be advantageous. Particularly suitable fillers include, for example, talc or calcium carbonate (chalk), alumina, silica gel, quartz powder, wood flour, and gypsum. For instance, chalk can be supplied in the range of ≥30 wt.% to ≤70 wt.%, wherein the slip properties of the filler, particularly the carrier, can be improved by chalk. Furthermore, they can be colored in known ways. In particular, it is possible to supply sheets comprising flame retardants.

[0054] In a preferred embodiment of the wall or floor panel, the carrier material of the panel may comprise a matrix material and a solid material, wherein the matrix material is present in an amount of ≥25 wt.-% to ≤55 wt.-%, particularly ≥35 wt.-% to ≤45 wt.-%, and wherein the solid material is present in an amount of ≥45 wt.-% to ≤75 wt.-%, particularly ≥55 wt.-% to ≤65 wt.-%, and wherein the matrix material and the solid material together are present in an amount of ≥95 wt.-%, particularly ≥99 wt.-%, wherein the solid material is formed, based on an amount of at least 50 wt.-%, particularly at least 80 wt.-%, particularly at least 95 wt.-%, of a solid composition consisting of at least a first layered silicate powder and a second layered silicate powder, forming the matrix material, wherein the matrix material is formed in an amount of at least 50 wt.-%, particularly at least 80 wt.-%, particularly at least 95 wt.-%, of a plastic composition consisting of a homopolymer and at least one first copolymer and a second copolymer. Surprisingly, it has been found that the method of the present invention can also be used to process compositions of several polymers that are difficult to process, particularly those with surfaces that are difficult to smooth and are filled with silicates. Surfaces can be treated at high linear speeds by the method according to the invention, and the smoothness obtained at high speeds is comparable to or better than that of prior art methods.

[0055] In detail, the carrier material includes solid materials and matrix materials. The matrix material is envisioned to exist in an amount of ≥25 wt.% to ≤55 wt.%, particularly ≥35 wt.% to ≤45 wt.%, based on the carrier material. Further specified, the solid material is defined as existing in an amount of ≥45 wt.% to ≤75 wt.%, particularly ≥55 wt.% to ≤65 wt.%, based on the carrier material.

[0056] The ratio of matrix material to solid material can be selected based on the required application area and panel performance. This allows for good adaptability to the desired application. However, in principle, it is preferable that the proportion of solid material is greater than or equal to the proportion of matrix material.

[0057] Further, the matrix material and the solid material are present together with the carrier material in an amount of ≥95 wt.-%, particularly ≥99 wt.-%.

[0058] In other words, it can be specified that, apart from the solid material and the matrix material, the amount of other substances present in the carrier material is only <5 wt.-%, preferably <1 wt.-%, based on the carrier material. Therefore, it may be advantageous for the carrier material to consist largely of solid material and matrix material. Particularly preferably, it can be specified that the matrix material and solid material are present together in an amount of 100 wt.-%, based on the carrier material, thus the carrier material consists of matrix material and solid material.

[0059] By limiting the amount of material used in the carrier, and thus producing the carrier using a small amount of material, the carrier can be produced particularly cost-effectively. Furthermore, the process control for producing the carrier or panel can be very simple, making production both simple and inexpensive.

[0060] In detail, it is further provided that the solid material is formed of a solid composition comprising at least one first layered silicate powder and a second layered silicate powder, and based on the solid material, the solid material has a content of at least 50 wt.-%, particularly at least 80 wt.-%, particularly at least 90 wt.-%.

[0061] In this paper, layered silicate powder is understood to refer to layered silicate powder in a manner known per se. Layered silicate is a known term for minerals from the silicate group whose silicate anions are typically arranged in layers.

[0062] For example, layered silicates should be understood as minerals derived from the mica, chlorite, kaolinite, and serpentine groups.

[0063] Therefore, solid materials are advantageously formed at least by layered silicates, which are primarily mineral materials, so that the material can be used, for example, in powder form or can exist in particulate form within a carrier material. In principle, solid materials can consist of powdered solids.

[0064] The advantage offered by layered silicates is that they allow the production of carriers with good mechanical properties, and at the same time, due to their layered structure, they can be easily processed into the corresponding powders.

[0065] In one embodiment of the invention, the first layered silicate powder or the second layered silicate powder may contain talc. Talc is understood, in a manner known per se, to represent magnesium silicate hydrate, which may, for example, have the chemical formula Mg3[Si4O] 10 [(OH)2]. In another embodiment of the invention, the first layered silicate powder and the second layered silicate powder may contain talc. In a further preferred embodiment, the first layered silicate powder and the second layered silicate powder may consist of at least 80 wt.-%, more preferably at least 95 wt.-%, of talc.

[0066] A particular advantage of talc is that it can be used to produce carriers very gently because it can be embedded into the matrix material without any problems and therefore does not cause abrasion to the pressing unit used.

[0067] In particular, mixtures of homopolymers with the first and second copolymers enable the matrix material to possess particularly advantageous properties. This type of material also offers the advantage that it can be formed into a carrier at low temperatures, for example, in the range of ≥180°C to ≤200°C, using the methods described above, thereby enabling particularly effective process control, such as exemplary linear velocities in the range of 6 m / min. Effective process control is particularly possible due to the advantageous mass flow rate of the carrier material. For example, the mixture of homopolymers with the first and second copolymers can achieve a mass flow rate of ≥20 g / 10 min to ≤30 g / 10 min, preferably ≥24 g / 10 min to ≤26 g / 10 min. In particular, the use of at least two copolymers can be advantageous, as this allows for improved elastic properties of the produced carrier. Specifically, panels produced using the carrier material can have advantageous flexural modulus. For example, panels can be provided based on a carrier material having a flexural modulus of ≥3000 MPa to ≤4000 MPa, preferably ≥3400 MPa to ≤3600 MPa. Furthermore, panels produced using the carrier material can have advantageous flexural strength. For example, panels based on the carrier material can be provided having a flexural strength of ≥30 MPa to ≤34 MPa, preferably ≥31 MPa to ≤33 MPa. Additionally, panels produced using the carrier material can have advantageous flexural strain. For example, panels based on the carrier material can be provided having a flexural strain of ≥2.0% to ≤2.8%, preferably 2.3% to 2.5%.

[0068] Preferably, the homopolymer, the first copolymer, and the second copolymer comprise polypropylene. Polypropylene is particularly suitable as a matrix material because, on the one hand, it is available at low cost, and on the other hand, as a thermoplastic, it exhibits good performance as a matrix material for embedding solid materials.

[0069] In a preferred embodiment of the wall or floor panel, the panel may comprise a multilayer plastic carrier material comprising N layer sequences ABA, wherein layer A comprises a first thermoplastic, layer B comprises a second thermoplastic, and wherein the first thermoplastic is virgin plastic, the second thermoplastic is recycled plastic, and wherein 250 ≥ N ≥ 2, preferably 200 ≥ N ≥ 3, preferably 125 ≥ N ≥ 4, and even more preferably 100 ≥ N ≥ 5. Surprisingly, this plastic carrier material can be produced at high linear speeds and with high dimensional stability by the method according to the invention. In this case, different layers can be deposited simultaneously as a co-extrusion on several nozzles, or deposited one after another and produced by the method according to the invention. Such wall, ceiling, or floor panels exhibit improved moisture resistance, particularly with reduced moisture or heat-induced expansion, as well as good mechanical properties and improved machinability. Furthermore, the plastic carrier material of the present invention is ecologically advantageous because it can be made from a significant proportion of recyclable plastics, thus conserving resources. In addition, ABCBA composites are suitable for this purpose, for example, as different paints, fillers, foams, indoor recyclable or polymer composites.

[0070] For example, the recycled thermoplastic of layer B may include amorphous polyethylene terephthalate (PET). PET is produced in large quantities in the packaging industry, where it is particularly used for food packaging and beverage bottles. Due to the stringent standards required in the food packaging sector, PET recycling is typically only possible to a limited extent. Although recycling methods, such as the URRC (United Resource Recovery Corporation) method, are now available, a significant amount of PET is not recycled locally but exported for the production of synthetic fibers. Here, the method of the present invention provides further possible uses for recyclable PET.

[0071] Preferably, based on the polymer ratio of layer B, the proportion of recyclable polyethylene terephthalate in layer B can be in the range of ≥10 wt.-% and ≤100 wt.-%. Particularly preferably, the amount of recyclable polyethylene terephthalate in layer B can be in the range of ≥15 wt.-% and ≤90 wt.-%, particularly ≥20 wt.-% and ≤80 wt.-%, based on the polymer content of layer B.

[0072] In addition to recyclable polyethylene terephthalate (PET), layer B may also provide virgin PET. Here, the proportion of virgin PET can be from ≥0 wt.% to ≤90 wt.% based on the polymer content of layer B; particularly preferably, the proportion of virgin PET in layer B can be from ≥10 wt.% to ≤80 wt.% based on the polymer content of layer B, especially from ≥15 wt.% to ≤75 wt.%.

[0073] In a preferred embodiment, particularly the PET-based polymer composition, a separate annealing / tempering process can be performed during construction. The annealing / tempering process helps release stresses present in the sheet due to the final shaping process, and thus improves dimensional stability. Subsequent heat treatment can be carried out, for example, in the form of a further tempering roller around which the mesh film extrusion passes. Other annealing options are a temperature-controlled circulating air line or a heated water bath, wherein the annealing temperature should be selected such that it does not lead to post-crystallization of the polymer material.

[0074] According to another embodiment of the invention, layer B may be specified to contain fillers in addition to thermoplastic plastics, wherein the fillers are preferably selected from chalk, non-asbestos silicates, preferably magnesium silicate, wood flour, expanded clay, volcanic ash, pumice, aerated concrete, and especially inorganic foam, cellulose or foaming agents.

[0075] Preferably, the filler ratio can be ≥1 wt.-% and ≤60 wt.-%, particularly ≥5 wt.-% and ≤50 wt.-%, based on the total mass of the material forming layer B.

[0076] The addition of fillers advantageously allows for the adjustment of the material properties of the multilayer plastic carrier material, such as its specific gravity or calorific value. The latter is particularly relevant to the problem of fire loads introduced into buildings through wall, ceiling, or floor coverings formed based on the corresponding multilayer plastic carrier. Typically, the proportion of thermoplastic or filler material is selectable depending on the application and performance of panels formed from the multilayer plastic carrier material according to the invention. This allows for good adaptability to the desired application.

[0077] Particularly preferably, layered silicates, such as talc, can be provided as fillers in layer B. The term talc should be understood to refer to magnesium silicate hydrate in a manner known per se, for example, it can have the chemical formula Mg3[Si4O3]. 10 [(OH)₂]. Therefore, the solid portion is advantageously formed at least by the main component of the mineral talc, which can be used, for example, in powder form or can exist in the carrier material in particulate form. In principle, the solid material can consist of powdered solids.

[0078] In a preferred embodiment of a wall or floor panel, the panel may comprise particles ≥0 μm and ≤600 μm in size and a particle distribution D. 50 The carrier material consists of wood and / or chalk particles with a particle size of ≥400 μm. According to a particularly preferred embodiment of the invention, the carrier material is composed of a blend of PE / PP block copolymer and wood. Here, the proportions of the PE / PP block copolymer and the wood can be ≥45 wt.% and ≤55 wt.% respectively. Furthermore, the carrier material may contain ≥0 wt.% and ≤10 wt.% of other additives, such as flow aids, heat stabilizers, or UV stabilizers. Here, the wood particles are ≥0 μm and ≤600 μm, with a preferred particle size distribution D. 50 The particle size distribution is ≥400 μm. Here, particle size distribution is based on volume diameter and refers to the volume of the particles. Particularly preferably, the carrier material is provided in the form of a granulated or granular pre-extruded mixture of PE / PP block copolymer and wood particles with a specific particle size distribution. The particle size of the particles and / or pellets is preferably in the range of ≥400 μm to ≤10 mm, preferably ≥600 μm to ≤10 mm, and particularly ≥800 μm to ≤10 mm.

[0079] To determine particle size distribution, commonly known methods such as laser diffraction can be used, which can measure particle sizes ranging from a few nanometers to a few millimeters. This method can also determine the size distribution of the raw material, and thus, the D... 50 Or D 10 The value, where the quantile represents the size of 50% or 10% of the measured particles that are smaller than the specified value. Attached Figure Description

[0080] Other technical features and advantages of wall or floor panels are specifically described herein with reference to the methods, apparatus and drawings.

[0081] The present invention will now be further explained with reference to the accompanying drawings and exemplary embodiments.

[0082] Figure 1 schematically shows a cross-sectional view of an apparatus design for performing the method according to the invention; Figure 2 schematically shows a plan view of an apparatus design for performing the method according to the invention; Figure 3 schematically shows a plan view of an apparatus design for performing the method according to the invention; Figure 4 schematically shows a roller assembly for guiding molten polymer material through a final shaping roller assembly; Figure 5 schematically shows a roller assembly for guiding molten polymer material through a final shaping roller assembly; Figure 6 schematically shows a roller assembly for guiding molten polymer material through a final shaping roller assembly having an enlarged portion; and Figure 7 schematically shows a cross-sectional view of one manner of performing the method according to the invention. Detailed Implementation

[0083] The apparatus 1 according to Figure 1 is suitable for a method of producing decorative wall or floor panels. Figure 1 shows a possible structure of the apparatus for producing decorative panels 1 in cross-section, specifically showing a unit of extrusion equipment 2 having a die 5, a pair of main rollers, and a final shaping roller assembly 4. In this embodiment, six final shaping rollers 7 are shown, each of which can be independently controlled relative to each other in its X and Y positions. The possible sequence of the rotation directions of the individual final shaping rollers 7 is indicated by arrows. The apparatus 1 schematically shows the extrusion equipment 2, which is divided into an extruder (not shown separately) for heat-treating polymer particles and the actual die 5. The strand of molten polymer exiting the die can be fed through the gap between the main roller assembly 3 and the individual main rollers 6. The height of the gap between the two main rollers 6 can be variably adjusted by moving the main rollers 6 relative to each other. After the molten polymer block has undergone initial shaping and, if necessary, cooling through the gap between the main rollers, the strand is conveyed to the final shaping roller assembly 4, in which the height of the molten polymer strand is further reduced or the final shaping roller is applied. The strand passes through the gap between the final shaping rollers 7, and its height varies as a function of the gap distance. Here, the final shaping rollers 7 do not always need to be equidistant from each other, thus allowing for different gap heights between them during the process. The final shaping rollers 7 also do not need to have the same height, but can be offset from each other. This can alter the mechanical tensile properties of the molten polymer strand. After finishing by the main roller assembly 3 and the individual final shaping rollers 7, the final shaped and flattened material can be decorated by a printing unit (not shown). Furthermore, the decorative surface of the panel can be provided with one layer, or, if desired, an additional layer, such as a protective coating.

[0084] Figure 2 shows a plan view of the apparatus 1 according to the invention. The extrusion apparatus 2, shown, with an extruder and a die, conveys molten polymer strands to a main roll assembly 3. The distance between the main roll assembly 3 and the extrusion apparatus 2 is variable and can be changed, for example, by a controlled electric motor. After the molten polymer block has passed through the roll gap of the main roll assembly 3, the carrier, having changed height and optionally been slightly cooled by the main roll assembly 3, is guided into a final shaping roll assembly 4, which consists of individual final shaping rolls 7 forming a roll gap between them through which the final shaped carrier passes and is further shaped. The individual final shaping rolls 7 can move integrally or separately in their relative positions. Furthermore, the roll surface temperature of each final shaping roll 7 can be controlled integrally or individually.

[0085] Figure 3 essentially illustrates the embodiment of Figure 2, with the decorative component 8 further shown here. The decorative component 8 is positioned downstream of the final setting roller 7 and applies the decoration to the final-shaped and optionally cooled carrier. The decorative component 8 may, for example, include an inkjet printer and additional units that apply an additional protective coating, at least partially, to the printed decoration. Alternatively, instead of using a printer, the decoration already applied to the carrier may be used, for example, deposited onto the final-shaped carrier by rollers. Furthermore, at this point, the carrier may be further cooled, shaped, or machined, for example, along its long sides.

[0086] Figure 4 illustrates a possible guidance of the molten polymer carrier 9 through the final setting roll gap. For example, the molten polymer carrier 9 can be cooled by deposition onto the final setting roll 7. In this assembly of individual final setting rolls 7, the thickness of the molten polymer carrier 9 is more likely to be altered by the mechanical tension of the rolls. The individual final setting rolls 7 are too far apart from each other to allow the molten polymer carrier 9 to be directly squeezed or compressed through the gap between the final setting rolls 7.

[0087] Figure 5 shows a final shaping roller assembly 4 with two final shaping rollers 7 similar to that in Figure 4, wherein the final shaping rollers 7 are closer together and form a gap less than the thickness of the molten polymer carrier 9. Since the molten polymer carrier 9 is at least partially thicker than the final shaping roller gap, the height of the molten polymer carrier 9 is leveled by the final shaping roller gap between the final shaping rollers 7.

[0088] Figure 6 again shows the cross-section of the final setting rollers of Figure 5, as well as an enlarged cross-section. In the enlarged cross-section, it can be seen that excess material of the molten polymer carrier 9 is pushed upward at the beginning of the final setting roller gap. As a result, the height of the molten polymer carrier 9 is adapted to the height of the final setting roller gap. The distance between the final setting rollers 7 allows adjustment of the height of the final setting roller gap, thereby adjusting the height of the carrier. According to the invention, it is advantageous that the final setting rollers 7 are so close that as little ambient air as possible can enter between the final setting rollers 7 and the molten polymer carrier 9, and the narrow gap ensures that as little additional air as possible is forced into the carrier surface. The latter can help improve the final set carrier surface.

[0089] Figure 7 illustrates another embodiment of the design of an apparatus 1 for producing decorative panels according to the present invention. Apparatus 1 also includes an extrusion apparatus 2, such as having a grooved die and an extruder. Molten polymer blocks are extruded through the die and pass through the roll gap of the main roller 3 to a final shaping roller assembly 4 comprising various final shaping rollers 7. In this figure, it is shown that the various final shaping rollers 7 do not necessarily have to be at the same height relative to each other. For example, by deflecting the final shaping rollers 7 in height, the mechanical forces and cooling performance in the air gap can be altered. Furthermore, the figure shows that an additional layer 10 can be applied within the final shaping roller assembly 4 comprising different final shaping rollers 7. This additional layer can be obtained, for example, as a roll and can be applied at different points on the final shaping roller assembly 4. For example, the additional layer can be a primer or a decorative undercoat. By applying the additional layer within the final shaping roller assembly 4, the final shaping rollers 7 can perform additional mechanical treatment on the layer, which can allow the additional layer to adhere better to the carrier. Furthermore, this ensures that the application of the additional layer does not cause the carrier to deviate from the desired dimensions in height, since both the carrier and the additional layer pass through the final shaping roller gap. After the additional layer is applied, decorative and protective coatings can be applied, at least partially, to the final shaped carrier via decorative component 8. Furthermore, the carrier can be further tempered / cooled in a defined manner, or subjected to mechanical post-processing by an additional device 11 suitable for this purpose, which may be a cooling or tempering surface or a mechanical milling machine for further shaping, such as the edges of the carrier.

[0090] Figure reference numerals: 1. Equipment; 2. Extrusion equipment; 3. Main roller assembly; 4. Final shaping roller assembly; 5. Die; 6. Main roller; 7. Final shaping roller; 8. Printer assembly; 9. Molten polymer carrier; 10. Additional layer; 11. Further post-processing.

Claims

1. Decorative wall or floor panels, including: A plate-like carrier formed from a thermoplastic polymer composition, a decoration applied to at least one surface of the carrier, and a protective coating disposed on the decoration, wherein the carrier comprises a multilayer structure comprising at least one layer sequence ABA, wherein layer A comprises a first thermoplastic polymer, and wherein layer B comprises a second thermoplastic polymer different from the first thermoplastic polymer, wherein layer B comprises a recyclable polymer material, and wherein the surface of the carrier is suitable for direct printing of the decoration without an intermediate decorative paper layer.

2. The decorative wall or floor panel according to claim 1, wherein the multi-layer structure comprises N layer sequences ABA, where 2 ≤ N ≤ 250.

3. The decorative wall or floor panel according to claim 1, wherein the multi-layer structure comprises N layer sequences ABA, wherein N is 5 or greater, or N is 20 or greater, or N is 50 or greater.

4. The decorative wall or floor panel according to claim 1, wherein the multi-layer structure is symmetrical with respect to the central plane of the carrier.

5. The decorative wall or floor panel according to claim 1, wherein the first thermoplastic polymer of layer A is a pure thermoplastic polymer.

6. The decorative wall or floor panel according to claim 1, wherein the recyclable polymer material of layer B includes recyclable polyethylene terephthalate, or recyclable polypropylene, or recyclable polyethylene.

7. The decorative wall or floor panel according to claim 1, wherein the recyclable polymer material constituting layer B comprises 10-100 wt.% polymer content.

8. The decorative wall or floor panel according to claim 1, wherein layer B further comprises a filler selected from chalk, layered silicates, talc, wood flour, mineral fillers, or combinations thereof.

9. The decorative wall or floor panel of claim 1, wherein the carrier comprises a matrix material present in an amount of 25 to 55 wt.%, and the solid material present in an amount of 45 to 75 wt.% based on the total weight of the carrier.

10. The decorative wall or floor panel of claim 1, wherein the solid material comprises 50 wt.% or more of layered silicate material.

11. The decorative wall or floor panel of claim 1, wherein the decoration is applied by direct printing.

12. The decorative wall or floor panel of claim 1, wherein the protective coating comprises a radiation-curable coating.

13. The decorative wall or floor panel of claim 1, wherein the carrier exhibits a flexural modulus of 3000 MPa to 4000 MPa.

14. The decorative wall or floor panel of claim 1, wherein the carrier is produced by extrusion and subsequent finishing using rotatable rollers.

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