Covered panel and method for manufacturing a covered panel

Abstract

This invention relates to a coated panel and a method for manufacturing a coated panel. Specifically, the invention relates to a coated panel having at least a substrate (2) and a top layer (3) applied thereon, wherein the top layer (3) comprises at least a decorative layer (4) and a translucent or transparent abrasion-resistant layer (5), characterized in that the abrasion-resistant layer (5) comprises a thermosetting acrylate resin or a thermosetting unsaturated polyester resin. Preferably, the resin is thermosetting partially or completely cured. In particular, the acrylate resin or unsaturated polyester resin is at least partially cured by a heat-initiated free radical crosslinking reaction. The invention also relates to a method for producing such a coated panel (1), particularly a method for producing a floor panel.

Description

[0001] This application is a divisional application of the invention patent application filed on November 5, 2019, with application number 201980073813.4 and invention title "Covered Panel and Method of Manufacturing Covered Panel". Technical Field

[0002] This invention relates to coated panels, particularly floor panels, and also to a method for manufacturing floor panels.

[0003] More specifically, the present invention relates to a panel having a substrate and a top layer applied thereon, having a decorative layer, such as a printed decorative layer. Such floor panels are well known, for example, from WO 97 / 47834. The floor panels disclosed in the aforementioned document particularly relate to floor panels having a substrate consisting primarily of an HDF sheet on which a laminate layer is directly pressed, one or more sheets of paper impregnated with melamine resin, preferably also including paper printed with, for example, wood grain or stone grain patterns, particularly so-called decorative paper. The aforementioned melamine resin forms a translucent, abrasion-resistant layer, particularly on the decorative paper, but transparency or translucency has many shortcomings. On the underside of the substrate is a backing layer or balancing layer, also based on paper impregnated with melamine resin. This backing layer provides compensation for residual tensile stress present in the cured melamine resin of the top layer. Very deep structures can still form on the cured melamine surface. So-called "white mountains" frequently occur. These are areas on the melamine surface where inclusions are concentrated. These mainly occur at locations where deep indentations or structures have been implemented. Background Technology

[0004] It is well known that the melamine surface of such laminated panels produces a clicking sound during use. Several solutions to this problem are known from the prior art. WO 03 / 016655 discloses applying a sound-insulating layer, such as a cork layer, under the melamine layer. Flexible monomer coatings for the melamine layer are known from WO 2010 / 088769 and other documents. WO 2009 / 101217 and WO 2010 / 070474 provide examples of laminated panels in which, instead of melamine resin, the top layer is primarily composed of polyvinyl chloride (PVC). WO 2010 / 070474 discloses a panel with a printed decorative layer, which can be formed on a substrate and decorated with a transparent PVC layer.

[0005] Additionally, a method is disclosed in WO 01 / 47726 for finishing panels using a printed decorative layer of acrylate resin cured by UV (ultraviolet) or electron beam. This process is difficult to integrate into existing laminated panel production methods and requires complex material logistics, sophisticated machinery, and high costs. For example, electron beam curing requires an inert atmosphere, which allows for board-level processing, and this technology is primarily used for smaller panels or thin sheets in physically enclosed lead spaces to eliminate the generation of unhealthy gamma rays. These lead-encapsulated assemblies are over 2.5 mm thick and very heavy. The photoinitiator required for UV radiation curing adversely affects the obtained surface quality. Due to the health risks posed by photoinitiators to humans, molecules used as photoinitiators are facing increasing pressure.

[0006] In panels with a top layer entirely composed of polyvinyl chloride (PVC), a decrease in scratch resistance was observed compared to conventional melamine surfaces. Furthermore, the PVC layer must be configured to be significantly thicker than the melamine layer to achieve comparable abrasion resistance. The properties and thickness of the PVC layer result in a plastic-like appearance for the flooring panels, particularly when intended to mimic products such as wood, stone, or ceramic. The embossing that can be achieved in a PVC layer is not clear, which detracts from the authentic appearance of the resulting imitation.

[0007] In panels where the top layer is obtained from UV-cured or electron-beam-cured acrylate, such as in WO 01 / 47726, favorable surface properties are achieved. A limitation of the embossing achievable in such a top layer is that a structural film must be applied, as in EP2019735. Summary of the Invention

[0008] The present invention primarily aims to provide an alternative coated panel, which provides a solution to one or more problems of prior art panels.

[0009] Therefore, in a first independent aspect, the present invention relates to a coated panel, preferably a board panel, wall panel, or furniture panel, having at least a substrate and a top layer applied thereon, wherein the top layer comprises at least a decorative layer and a translucent or transparent abrasion-resistant layer, characterized in that the abrasion-resistant layer comprises a thermosetting acrylic resin and / or a thermosetting unsaturated polyester resin. Preferably, the resin is partially or completely cured in a thermosetting process.

[0010] In this document, cured unsaturated polyester resin refers to a polyester resin that is unsaturated before curing and can be cured by crosslinking the double bonds in the unsaturated polyester resin.

[0011] The use of thermosetting acrylate resins and / or thermosetting unsaturated polyester resins opens up new possibilities for designing abrasion-resistant layers while retaining the excellent qualities of abrasion-resistant layers made from either acrylate or unsaturated polyester resins. For example, the abrasion-resistant layer can therefore be cured by hot pressing using structured clamping elements. Surprisingly, the inventors have found that the structure of the clamping elements is very advantageously replicated in the curing of acrylate resins and / or the curing of unsaturated polyester resins. Unlike the curing of melamine resins, there is no so-called chemical moisture or moisture appearing as a reaction byproduct in the curing reaction of acrylate resins and / or the curing of unsaturated polyester resins. Therefore, even when working with deep structures (e.g., local depths greater than 400 μm relative to the entire surface, even 1 mm or more), the risk of inclusions forming in the translucent layer is limited.

[0012] Furthermore, the inventors discovered that thermosetting acrylate resins and / or thermosetting unsaturated polyester resins can exhibit better transparency than thermosetting melamine resins (such as melamine resins available in prior art laminated panels). The inventors attribute this to the strong curling properties of condensation-polymerized melamine resins. Therefore, due to the brittleness of melamine resins, cured melamine resins exhibit numerous microcracks, which is not the case in the wear-resistant layer based on the thermosetting acrylate resin of this invention.

[0013] Furthermore, the inventors were able to determine that, in the case of the present invention, the residual tensile stress that may exist in the wear-resistant layer after curing is much lower than that in the laminated panels of the prior art, thereby greatly reducing the risk of bending of the obtained panel or its components, even when working without a backing layer.

[0014] The resulting abrasion-resistant layer is softer than a melamine surface and has lower residual tensile stress on the surface, thus producing a more acceptable scratching sound, especially comparable to that of real wood.

[0015] Furthermore, compared to UV-cured acrylate resins, thermosetting allows for more uniform curing. When using UV radiation for curing, the penetration depth of light is limited. However, the thermosetting of this invention can be initiated by one or more thermal initiators that are uniformly or substantially uniformly mixed with the acrylate resin or unsaturated polyester resin. In this way, the curing reaction can proceed almost simultaneously and / or to the same extent across the entire thickness of the layer formed from the acrylate resin or unsaturated polyester resin. Additionally, thicker cured layers can be formed, for example, between 50 and 1000 μm, more specifically between 60 and 300 μm, and even more specifically between 100 and 300 μm.

[0016] If the aforementioned acrylate resin or unsaturated polyester resin is cured at least through a thermally initiated free radical crosslinking reaction, this primarily indicates the quality of the acrylate resin or unsaturated polyester resin. The curing preferably includes at least the crosslinking of the double carbon bonds present in the acrylate resin or unsaturated polyester, for example, in acrylate resins or unsaturated polyester resins cured by UV or electron beam.

[0017] Depending on specific possibilities, the aforementioned acrylate resin is cured via a thermally initiated free radical crosslinking reaction (whereby the double carbon bonds present in the acrylate resin are crosslinked) and a crosslinking reaction via oligomers or monomers having hydroxyl (-OH) and / or amine (-NH2) and / or carboxyl (-COOH) functionalities with isocyanates, aziridines, carbodiimides, etc. This crosslinking reaction is promoted by the temperature used during the first crosslinking reaction. According to a specific example, the acrylate resin comprises or is composed of a polyurethane acrylate resin.

[0018] It is important to note that the use of curing agents (e.g., isocyanates or aziridines) in UV-curable coatings is a known dual-curing process to the inventors. Such curing agents cause the second internal crosslinking of acrylate resins, particularly those with hydroxyl (-OH) and / or carboxyl (-COOH) and / or amine (-NH2) functionalities, to proceed in an uncontrolled manner and may be delayed for a considerable period after the initial UV curing. This particular possibility provides the possibility of providing a durable layer to a coated panel obtained through the application of a dual-curing system, where the first crosslinking involves thermal curing. Using the heat energy from the first crosslinking, the second crosslinking is initiated in a controlled manner and can be completed in a short time. In other words, this is an “instant dual-curing system.”

[0019] Depending on the specific possibilities, the curing of acrylate resins or unsaturated polyester resins may be further promoted by thermosetting accelerators (such as, for example, 2,4-pentanedione or N,N-diethylacetylacetamide) and / or thermosetting accelerators (such as cobalt-free accelerators, such as copper or iron complexes, or by cobalt octoate, amine diethylaniline, dimethyl p-toluidine or ethoxylated p-toluidine).

[0020] It is clear that the presence of a thermal initiator in the acrylic resin or unsaturated polyester resin used can play an important role in the quality and embossing of the resulting wear-resistant layer.

[0021] Thermal initiators can be more generally defined as thermally unstable molecules that decompose or disintegrate into at least one or more free radicals upon exposure to heat. These free radicals then function similarly to those generated by known photoinitiators during the UV curing of acrylate resins. The thermally generated free radicals initiate the polymerization of the double-carbon bonds of the acrylate functional groups present in the acrylate resin.

[0022] For the same purpose as the first aspect, according to a separate second aspect, the present invention relates to a coated panel having a substrate and a top layer applied thereon, wherein the top layer comprises at least a decorative layer and a translucent or transparent abrasion-resistant layer, characterized in that the abrasion-resistant layer is obtained based on a mixture of at least one aspect an acrylic resin and / or an unsaturated polyester resin and, on the other hand, a thermal initiator. It is clear that the coated panel of the second aspect may exhibit the features of the first aspect or its preferred embodiments. In particular, the mixture may further comprise a crosslinking agent, such as isocyanate, aziridine, carbodiimide, etc., thereby obtaining the abrasion-resistant layer through an instant dual-curing system mentioned in the context of the first aspect. Additionally, the mixture may also comprise thermosetting accelerators and / or promoters, such as those mentioned in the context of the first aspect of the invention.

[0023] Preferably, the aforementioned thermal initiator is an organic peroxide, preferably benzoyl peroxide, methylbenzoyl peroxide, TPBIN (tert-butylperoxide-3,5,5-trimethylhexanoate), or lauroyl peroxide. The inventors have found that these thermal initiators have suitable minimum activation temperatures, which are necessary for achieving decomposition into at least one or more free radicals, thus allowing for a fully cured wear-resistant layer with acceptable energy consumption, particularly at appropriate curing temperatures. Among the aforementioned peroxides, lauroyl peroxide has the lowest activation temperature, thus enabling rapid curing of the resin. However, in some cases, such as during curing, when fairly deep indentations form in the wear-resistant layer, for example, to a depth of 0.1 mm or greater, or when adhesion to the underlying polyurethane-containing layer is desired, it is desirable for the resin to maintain its fluidity for a longer period. In such cases, it is preferable to use at least benzoyl peroxide or methylbenzoyl peroxide as the thermal initiator. Of the latter initiator, methylbenzoyl peroxide is of most interest because it produces toluene, which is less toxic, as the reaction product, rather than benzene in the case of benzoyl peroxide. In this regard, it should also be noted that the reaction with lauroyl peroxide leads to the formation of non-toxic aliphatic compounds.

[0024] Other examples of organic and inorganic peroxides suitable for use as thermal initiators are 2-butanone peroxide, persulfate, peroxydiphosphate, and persulfate.

[0025] Other examples of peroxides suitable for use as thermal initiators include ketone peroxides, diacyl peroxides, ketal peroxides, hydroperoxides, peroxydicarbonates, and peroxymonocarbonates, with tert-butyl peroxide-3,5,5-trimethylhexanoate (TPBIN) being preferred.

[0026] In addition to peroxides, azo polymerization initiators such as azonitrs, azo esters, hyponitrites, and / or azoamides can be used as alternatives. Specific examples include azobisisobutyronitrile (AIBN), 2-methylbutyronitrile (AMBN), and azopentonitrile (AVN). Another option is to use cesium ions.

[0027] Of course, two or more of the above-mentioned thermal initiators can be combined.

[0028] Preferably, the mixture contains 0.1-5 parts of thermal initiator per 100 parts of acrylate resin or per 100 parts of unsaturated polyester resin, and more preferably 0.5-2 parts of thermal initiator per 100 parts of acrylate resin or per 100 parts of unsaturated polyester resin, and even more preferably 0.1-2 parts of thermal initiator per 100 parts of acrylate resin or per 100 parts of unsaturated polyester resin (a smaller amount of thermal initiator can be used to obtain a similar final cure if additional crosslinking is performed with UV light). The chain length of the obtained polymeric acrylate resin or polymeric unsaturated polyester resin can be adjusted by changing the concentration of the thermal initiator. Using a larger amount of thermal initiator results in a faster reaction completion and a shorter chain length, while using a smaller amount results in a longer chain length. Using 0.5-2 parts of thermal initiator per 100 parts of acrylate resin or per 100 parts of unsaturated polyester resin achieves a balance between reaction rate and degree of crosslinking or chain length. The preferred time range for curing to half or full cure allows for sufficient resin flow. Resin flow is important, for example, when replicating the structure of a clamping element onto the surface of a wear-resistant layer. This specifically requires displacing acrylate or unsaturated polyester resin into all the embossed portions of the clamping element.

[0029] In the case of benzoyl peroxide, methyl benzoyl peroxide and / or lauroyl peroxide, 0.5 to 2 parts per 100 parts of acrylic resin are used to achieve adequate curing with acceptable energy consumption within an economically acceptable timeframe while maintaining sufficient flow.

[0030] As is clear from the above, the flowability of acrylate resins or unsaturated polyesters can be adjusted by selecting the thermal initiator and its concentration. In the case of acrylate resins, the flowability can be optionally further extended by increasing the content of reactive diluent monomers or bifunctional monomers (e.g., dipropylene glycol diacrylate (DPGDA)) in the acrylate resin. Preferably, the acrylate resin contains 20 to 60% by weight of monomers, preferably monofunctional and / or bifunctional and / or trifunctional and / or tetrafunctional monomers.

[0031] Preferred embodiments that can be applied in conjunction with the first, second, third and / or fourth aspects of the present invention are discussed below.

[0032] Preferably, the abrasion-resistant layer of the coating panel of the first and / or second aspects contains trace amounts of peroxides, such as benzoyl peroxide, methyl benzoyl peroxide, and / or lauryl peroxide.

[0033] Preferably, the wear-resistant layer contains at least trace amounts of reaction products generated from the reaction between the thermal initiator and the acrylate resin. For example, the wear-resistant layer may contain trace amounts of benzene, toluene, or an aliphatic compound.

[0034] Preferably, the wear-resistant layer is cured uniformly or substantially uniformly over its entire thickness.

[0035] Preferably, the thermosetting process involves chemical crosslinking—preferably double carbon bonds present in acrylate resins—and / or double carbon bonds present in unsaturated polyester resins. This crosslinking reaction produces highly advantageous abrasion resistance properties. The degree and type of polymerization can be controlled by varying the concentration of the initiator (thermal initiator and / or photoinitiator) and by using a certain amount of UV light before adding additional UV curing to the lacquer base prior to the pressing process. While it is known that EB curing proceeds more uniformly through the matrix, it can be said that, during thermosetting, at a given texture depth and embossed structure, there is a warm front that provides less uniform curing over time. This can affect the adhesion properties or chain length of the matrix.

[0036] Preferably, the wear-resistant layer is obtained based on a mixture containing at least one acrylate resin and / or an unsaturated polyester resin and on the other hand a photoinitiator. More preferably, the mixture contains 0.1-5 parts of photoinitiator per 100 parts of acrylate resin or per 100 parts of unsaturated polyester resin.

[0037] More preferably, the mixture contains 0.1-5 parts of two different photoinitiators per 100 parts of acrylate resin or per 100 parts of unsaturated polyester resin. Preferably, the photoinitiators are selected such that one photoinitiator cures the top 20 μm of the abrasion layer (surface curing), while the other photoinitiator cures the abrasion layer deeper (depth curing). This allows for more favorable curing of the abrasion layer.

[0038] Preferably, the decorative layer comprises a carrier sheet provided with a synthetic material, such as paper. For example, it can be printing paper used for producing DPL-type laminated panels and / or paper with a Gurley value of less than 30 seconds or even less than 25 or 20 seconds. A lower Gurley value facilitates the incorporation of the synthetic material into the paper core. Preferably, the surface weight of the paper is 40 to 250 grams per square meter, more preferably 55 to 150 grams per square meter, or 65 to 90 grams per square meter. Higher surface weights, particularly 90 to 150 grams per square meter, are preferred for use in furniture panels, while lower surface weights, particularly 65 to 90 grams per square meter, are preferred for flooring panels. Printing can be achieved in a similar manner, for example by offset printing with printing cylinders, and / or digitally, for example by inkjet printing, preferably in a so-called single-pass printer.

[0039] Instead of paper made of synthetic materials, films made of synthetic materials, such as PVC (polyvinyl chloride) or PET (polyethylene terephthalate) films (whether printed or not), or finishes, can also be used. It should be noted that films made of synthetic materials are examples of moisture-impermeable layers, and the inventors have discovered that since no chemical moisture is generated during the curing process of acrylate resins, thermosetting abrasion-resistant layers, especially thermosetting abrasion-resistant layers based on acrylate resins, can be formed on films formed of synthetic materials or other impermeable layers. In the laminates of prior art panels, the inventors assume that chemical moisture migrates along the direction of the substrate, and in the prior art, impermeable layers above the substrate are undesirable.

[0040] Preferably, the synthetic material provided on the carrier sheet is a synthetic material containing double carbon bonds.

[0041] According to a specific embodiment, a portion of the aforementioned wear-resistant layer is formed from a synthetic material provided on the carrier sheet, wherein this portion is located between the decorative layer itself (e.g., a printed pattern or finish) and a portion of the wear-resistant layer formed from a thermosetting acrylate. The portion of the wear-resistant layer formed from the synthetic material of the decorative layer may contain hard particles, such as particles of alumina, silicon oxide, or silicon carbide.

[0042] Preferably, the synthetic material disposed on the carrier sheet is selected from: amino resins, urea-formaldehyde, melamine-urea-formaldehyde, melamine-formaldehyde, polyurethane dispersions, urethane-acrylic copolymer dispersions, acrylates, latex, melamine acrylate, reactive acrylate monomers, optionally in combination with crosslinking agents such as carbodiimides, polyisocyanates, or aziridines. The synthetic material is preferably applied to the carrier sheet in the form of an aqueous mixture or dispersion, for example by impregnation, one or more roll coatings, and / or one or more spraying or pouring methods. This dispersion can be anionic, cationic, or nonionic stable. In the case where the carrier sheet contains a digitally printed decorative layer, the dispersion is preferably cationic stable to prevent possible salts or acids in the optional inkjet receiver coating from damaging the stability of the polyurethane dispersion. Of course, the synthetic material described above is not excluded as melamine-formaldehyde. In this case, for example, a coating that promotes bonding with thermosetting acrylate resins or thermosetting polyester resins is applied to the surface of the carrier sheet on which the synthetic material facing the wear layer is provided. This coating can comprise aliphatic polyurethane dispersions, latex dispersions, water-based UV-curable materials (e.g., water-based UV-curable acrylate resins), melamine acrylates, chemically modified melamine resins, or etherified melamine resins. Of course, it is not excluded that the above-mentioned synthetic materials are thermosetting acrylate resins or unsaturated polyester resins. For example, in this case, the use of cationically stable polyurethane dispersions to form a coating on printed paper and / or to impregnate printed paper is itself an important discovery. According to a particular independent aspect, the invention also relates to a method for producing a coated panel having a substrate and a decorative top layer of printed paper, characterized in that the method comprises at least the step of: providing a cationically stable polyurethane dispersion on printed or to-be-printed paper. It is clear that the printing on such paper is preferably carried out digitally and / or such paper contains a previously applied coating with a pH less than 7 (preferably 5 or lower), such as an inkjet receiver coating. This particular aspect may, of course, show other preferred features, such as those described earlier in this paragraph or in the context of other aspects of the invention. The polyurethane dispersions used may also further exhibit the following properties.

[0043] According to an important example, a polyurethane dispersion is applied to a carrier sheet. Preferably, the polyurethane coating on the carrier sheet achieves a König hardness (…). The hardness is 20 to 160 seconds, 40 to 120 seconds, preferably 40 to 100 seconds, and more preferably 40 to 80 seconds. The inventors have found that this hardness results in better adhesion to thermosetting acrylate resins or thermosetting unsaturated polyester resins for the abrasion-resistant layer. Polyurethane coatings with higher König hardness are more likely to cause adhesion problems. Furthermore, the inventors have found that softer polyurethanes (especially those with a König hardness of 20 to 160 seconds, 40 to 120 seconds, and preferably 40 to 80 seconds) exhibit better scratch resistance. In this embodiment, the polyurethane can also be located in the core of the carrier sheet. According to another important possibility, the core of the carrier sheet is impregnated with a condensation resin (such as melamine-based resin), while the polyurethane coating is primarily present on the surface of the carrier sheet. This possibility provides good crack resistance on the carrier sheet in an economical manner while retaining the advantages of the polyurethane coating, such as reduced clicking or other noise. Preferably, the polyurethane coating exhibits an elongation of 40% to 400%, 100% to 300%, and preferably 120% to 250%. High elongation provides a bridge between the decorative paper (which, as described above, can optionally be provided in the core using condensation polymerization, such as melamine-based resins) and the thermosetting acrylate resin. Preferably, the aforementioned acrylate resin is obtained at least based on polyfunctional acrylate or methacrylate monomers and / or oligomers (such as hexafunctional acrylate or methacrylate oligomers). Polyfunctional acrylate or methacrylate oligomers can provide a rigid layer, but this layer should be as brittle and abrasion-resistant as possible.

[0044] Based on the above important examples, it is preferable to apply a polyurethane dispersion with a weight of 5 to 60 grams of dry matter per square meter, and more preferably 10 to 20 grams of dry matter per square meter, onto the carrier sheet.

[0045] Preferably, the polyurethane dispersion applied according to the above important examples is water-based and contains acrylate functional groups, and / or the dispersion contains UV acrylates, such as epoxy-modified polyurethane acrylates, such as commercially available NeoRad UV20 40W. Improved adhesion can be obtained by using a thermosetting acrylate resin through this preferred embodiment. To promote film formation of the PU dispersion, it is preferable to use 1 to 10% by weight, preferably 2 to 6% by weight, of a solvent in the dispersion. For example, DPnB (dipropylene glycol n-butyl ether), DPM (dipropylene glycol methyl ether); PM (propylene glycol methyl ether), 2-butoxyethanol, or diethylene glycol can be used.

[0046] Preferably, the PU dispersion exhibits an MFFT (Minimum Film-Forming Temperature, ISO 2115) of 0 to 40°C, 6 to 20°C, and more preferably 5 to 15°C.

[0047] A 100% reactive acrylic primer can be used. This primer penetrates the melamine layer and can covalently bond to the subsequently applied clear topcoat. Such an acrylic primer can, for example, consist of HDDA (1,6-hexanediol diacrylate), ACMO (acryloylmorpholine), melamine acrylate, or acid-bonding acrylate.

[0048] Preferably, the acrylate resin is obtained at least based on monofunctional or difunctional acrylate or methacrylate monomers and / or oligomers. Difunctional acrylates or methacrylate oligomers can produce a tough or less brittle abrasion-resistant layer. Trifunctional and / or tetrafunctional acrylates can also be used.

[0049] Preferably, acrylate monomers or oligomers can be used because they are more reactive than methacrylate monomers or oligomers.

[0050] Preferably, the acrylate resin is aliphatic. This type of acrylate resin can minimize aging and / or discoloration.

[0051] Preferably, the acrylate resin comprises 5 to 80% by weight of monomers, or more preferably 5 to 60% by weight, which may be monofunctional, difunctional, or polyfunctional monomers. The monomers in the acrylate resin may have one or more of the following effects: increasing viscosity to a desired value, improving adhesion by better absorption in adjacent layers (e.g., substrates), or positively or negatively affecting reactivity in decorative layers, significantly influencing the flexibility and / or brittleness of the resulting abrasion-resistant layer, for example, setting the operating range in terms of the temperature used, and positively influencing chemical resistance. For example, using polyfunctional monomers can achieve better crosslinking, curing, and chemical resistance. For this purpose, for example, trifunctional monomers, such as TMPTA, can be used. For difunctional monomers, given the short chain length, it is also possible to promote crosslinking and curing. For example, DPGDA (dipropylene glycol diacrylate) monomers can be used, which achieves sufficient flow during the solidification process.

[0052] According to the most preferred embodiment, the above-mentioned acrylate resin is obtained from a mixture of at least two or more acrylate oligomers with different functionalities, preferably a mixture of polyfunctional and difunctional acrylate oligomers, wherein "more" is considered to mean more than two. Using such a mixture, the hardness and toughness required for the final wear-resistant layer can be achieved.

[0053] Using acrylate resins as a wear-resistant layer also allows for the blending of acrylates with specific properties. For example, the aforementioned acrylate resins can be obtained at least from chemically modified acrylates (such as fluoroacrylates). By adding chemically modified acrylates to acrylate resins, properties such as hydrophobicity, ease of maintenance, fingerprint resistance, and antibacterial properties can be obtained. Other possible additives to acrylate resins include metallic pigments and materials that improve tactile interaction. The additives mentioned herein have no or substantially no effect on the thermosetting of acrylate resins.

[0054] Preferably, at least some hard particles, such as alumina particles, silica particles, or silicon carbide particles, are added to the acrylate resin or unsaturated polyester resin. Alternatively, the hard particles are located between the decorative layer and a portion of the abrasion-resistant layer formed by the acrylate resin and / or thermosetting unsaturated polyester resin. In cases where the decorative layer comprises a carrier sheet provided with a synthetic material, the hard particles may be located within a layer formed of that synthetic material. Preferably, at least 5 grams or at least 10 grams of such hard particles are added per square meter. These particles can further increase abrasion resistance. Preferably, the particles have a mesh size of F100 or smaller, but preferably not less than F320. The latter roughly corresponds to an average particle size of 30 to 125 μm. The abrasion resistance of the obtained abrasion-resistant layer can be adjusted by its thickness, regardless of whether hard particles are present. Preferably, the thickness of the abrasion-resistant layer obtained based on the thermosetting acrylate resin is at least 50 μm, and preferably at least 100 μm.

[0055] Preferably, the wear-resistant layer is obtained by using 10 to 300 grams of the aforementioned acrylate resin or the aforementioned unsaturated polyester resin per square meter. In the case of furniture panels, the wear-resistant layer is preferably obtained by using 10 to 80 grams (dry solids), and more preferably 10 to 30 grams (dry solids), of acrylate resin or thermosetting unsaturated polyester resin per square meter, while in the case of floor panels, the wear-resistant layer is preferably obtained by using 30 to 160 grams of acrylate resin or unsaturated polyester resin per square meter.

[0056] Preferably, in any embodiment of the coated panel according to any aspect of the present invention, the wear-resistant layer consists of different layers. The wear-resistant layer includes multiple layers having the characteristics of embodiments of the wear-resistant layer described in the first and / or second and / or fourth aspects of the present invention, and / or obtainable by any embodiment of the method of the third aspect of the present invention.

[0057] Thermosetting acrylate resins or unsaturated polyester resins can be applied in multiple layers to the wear-resistant layer. These layers can have the same chemical formulation, but they can also be different from each other to optimize the relationship between performance and cost or to optimize the flow behavior in the press.

[0058] Preferably, the compositions of these multilayers are different from each other. More preferably, the uppermost layer of the wear-resistant layer comprises one or more of fluorinated acrylate, micro alumina, silicone acrylate, or nano silica.

[0059] Preferably, the coated panel according to any independent aspect of the invention is a floor panel, preferably suitable for floating installation. The abrasion-resistant layer can exhibit exceptionally high abrasion and / or scratch resistance, but it is also soft enough to significantly improve noise reduction compared to conventional melamine surfaces.

[0060] Preferably, the coated panel has an embossed surface. Preferably, the embossing also displays gloss variations. These gloss variations can occur in areas with at least two distinct gloss levels, which can be clearly distinguished by the user and therefore by the naked eye. More specifically, it is preferred that at least two gloss levels are used for the selected areas to make the designated area clearly appear as a matte area, while other areas appear as non-matte or glossy areas. The gloss level of most matte areas on the coated panel (e.g., flooring panels) is preferably 10 or more preferably less than 10, while the gloss level of less matte or glossy areas is greater than 10, and more preferably greater than 20, all measured according to DIN 67530. Regardless of the absolute gloss level used, the gloss difference between the matte and glossy areas of the coated panel is preferably at least 10.

[0061] For the same purpose as the first and second aspects, according to a separate third aspect, the present invention also relates to a method for producing a coated panel, wherein the panel comprises at least a substrate and a top layer applied thereon, and the top layer comprises at least a decorative layer and a translucent or transparent abrasion-resistant layer, characterized in that the method comprises at least the following steps:

[0062] - The step of applying one or a combination of acrylic resin, unsaturated polyester resin, and a coating composition containing acrylic resin to the above-mentioned decorative layer; wherein the acrylic resin, unsaturated polyester resin, or coating composition optionally contains a thermal initiator and optionally a photoinitiator; and

[0063] - The step of at least partially curing the aforementioned acrylate resin, unsaturated polyester resin, or coating composition by hot pressing is used to form at least a portion of the aforementioned wear-resistant layer. It goes without saying that the possibilities mentioned in the context of the first and / or second aspects of the invention can be relied upon for the acrylate resin, unsaturated polyester resin, or coating composition, and optionally the thermal initiator. Preferably, the coating composition or the acrylate resin comprises at least a multifunctional acrylate oligomer and 0.5 to 2 parts per 100 parts of acrylate resin as a thermal initiator; and more advantageously, 0.1 to 2 parts per 100 parts of benzoyl peroxide, methyl benzoyl peroxide, or lauroyl peroxide as a thermal initiator, and even more advantageously, 0.1 to 1 part per 100 parts of benzoyl peroxide, methyl benzoyl peroxide, or lauroyl peroxide as a thermal initiator. Curing under pressure maximizes the potential of the thermosetting acrylate resin or thermosetting unsaturated polyester resin. It is clear that, under these circumstances, the aforementioned instant dual-curing system can be applied, in which a lower amount of thermal initiator can be used.

[0064] When using acrylic resins (whether or not they constitute the above-described coating composition) or unsaturated polyester resins, it is preferable to use acrylic resins or unsaturated polyester resins that contain oligomers and monomers.

[0065] Preferably, in the method according to the third aspect of the invention, at least hard particles such as alumina particles, silica particles or silicon carbide particles are added to the acrylate resin or unsaturated polyester resin or coating composition.

[0066] Preferably, the pressing is performed using a so-called short-cycle press or a single-daylight press. Of course, the use of a continuous press is not excluded, preferably a press utilizing moving pressure belts between which the entire component to be pressed moves, or hot press rollers. A continuous press can also be used, utilizing one or more pressure cylinders, preferably textured. This invention is particularly important when texturing the abrasion-resistant layer using extrusion cylinders (in which the top layer of the coated panel is provided with an embossed finish). In this technique, the residence time under pressure is particularly short, and even within such a short residence time, the structure of the pressing element can be adequately achieved with fast-curing acrylate or fast-curing polyester resins. During this process, an embossed finish is provided on the top layer of the coated panel, including precise replication of different gloss levels.

[0067] Preferably, the pressing is performed at a temperature of 70 to 220°C (preferably 120 to 220°C) and / or a pressure of 5 to 80 bar. The inventors have also performed the pressing at 195°C and 40 bar (approximately 40 kg / cm²) in a short-cycle press. 2 A pressing time of 22 seconds yielded favorable results. This process parameter corresponds to the process parameters used in the pressing of melamine-based laminated panels. However, such high temperature and high pressure are not necessarily necessary in the pressing of thermosetting acrylate resins or thermosetting unsaturated polyester resins, and the process parameters can be adjusted within a wide range; more specifically, they can be reduced until the desired effect is achieved.

[0068] As described above, when using structured clamping elements, thermosetting acrylate resins (including acrylate resins in coating compositions) or thermosetting unsaturated polyester resins preferably exhibit sufficient flow. For this purpose, it is preferable to use at least benzoyl peroxide or methyl benzoyl peroxide as an initiator.

[0069] The inventors have discovered that rapidly increasing the pressing pressure can be important to induce deformation by the pressing element before the acrylate resin cures substantially, thereby forming the desired structure on the surface of the panel and / or in the substrate. This is also important when a thermosetting acrylate resin abrasion layer is to be adhered to, for example, a polyurethane-containing underlayer, such as to a carrier sheet or decorative paper treated on a surface with the polyurethane dispersion described above.

[0070] Preferably, the above-mentioned pressing is performed with the assistance of a structured pressing element (e.g., of a type known in itself from WO 2009 / 043910) (such as a structured pressure plate).

[0071] During pressing, a frame or box is used, extending along all edges of the material to be pressed. The purpose of this frame or box is to optionally prevent the acrylic resin or unsaturated polyester resin from splashing out of the press as pressure increases. Furthermore, the thickness of the frame or box is chosen to allow for setting the exact desired thickness of the abrasion-resistant layer. Additionally, the frame or box ensures that sufficient pressure is applied to the cured acrylic resin or cured unsaturated polyester resin.

[0072] According to a specific embodiment, the method of the present invention further includes the step of post-curing the pressed wear-resistant layer by ultraviolet and / or electron radiation, both preferably performed under an inert atmosphere. An important example of this specific embodiment is that a surface with embossed and / or gloss variations comparable to those achievable on a melamine surface can be achieved, but with the quality and noise characteristics of an electron beam-cured surface. For this purpose, the wear-resistant layer, pressed and structured by a clamping element, can be post-cured by electron radiation under an inert atmosphere.

[0073] Preferably, the pressing is performed on a stack comprising at least a substrate, a decorative layer, and an acrylic resin, unsaturated polyester resin, or coating composition. In this way, a method corresponding in many respects to a laminated panel manufacturing process is realized, allowing the method to be easily incorporated into existing laminate production.

[0074] Preferably, the step of applying an acrylic resin, an unsaturated polyester resin, or a coating composition to the decorative layer is performed when the decorative layer is already part of a stack comprising at least a substrate and a decorative layer.

[0075] Preferably, as described above, the decorative layer comprises a carrier sheet, such as paper, and in this case, the method preferably also includes at least providing a synthetic material to such carrier sheet. The method may further include the step of providing rigid particles, such as particles of alumina, silicon oxide, or silicon carbide, to the synthetic material. This step can be carried out in practice in various ways, such as mixing the rigid particles into the synthetic material before providing it to the carrier sheet, or applying the rigid particles to the synthetic material after it has been provided to the carrier sheet, for example by dispersing the particles or by applying a flowable mixture or dispersion containing the particles by roller coating, spraying, or jetting.

[0076] Preferably, the step of providing the carrier sheet with a synthetic material includes at least applying a water-based or water-based UV-curable synthetic material to the carrier sheet.

[0077] Preferably, the step of providing the synthetic material for the carrier sheet includes at least the application of a UV-curable substance, such as an acrylate resin and / or an unsaturated polyester, wherein this substance further comprises a thermal initiator. This can be a so-called hydro-UV or fully hydro-UV system containing a thermal initiator. Solvent-based acrylates can also be used; after drying, these form a non-stick film. This system can contain relatively long oligomers. The treated carrier sheet can be dried to a non-stick state. The final curing of the oligomers can then be performed in pressing.

[0078] As described above, the synthetic material provided on the carrier sheet preferably further comprises hard particles, such as corundum particles, for example alumina particles.

[0079] It should be noted that the application of the acrylic resin, unsaturated polyester resin, or coating composition to the decorative layer can be performed in two or more stepwise steps. This embodiment allows for the application of a larger quantity of the acrylic resin or unsaturated polyester resin or coating composition in a more uniform manner. Furthermore, acrylic resins or unsaturated polyester resins or coating compositions with different compositions can be applied in the respective stepwise steps. For example, an acrylic resin with specific functionalities, such as an acrylic resin providing higher cleanliness, can be added only to the acrylic resin layer closest to the panel surface or to which the panel surface is to be formed, or hard particles, such as alumina, can be added only to a designated layer.

[0080] Additionally, it should be noted that when the coating composition, acrylic resin, or unsaturated polyester resin contains a photoinitiator, this coating composition, acrylic resin, or unsaturated polyester resin may be gelled before pressing and / or after pressing, under UV radiation with or without an inert atmosphere (to counteract oxygen inhibition) before post-curing. In cases where the coating composition, acrylic resin, or unsaturated polyester resin is applied in two or more stepwise steps, any UV radiation prior to pressing does not necessarily have to be applied to all partial layers. For example, it is useful to at least prevent partial gelling of the uppermost layer in order to retain sufficient flow of the coating composition, acrylic resin, or unsaturated polyester resin during pressing for creating indentations in the layer by a texturing pressing element, in such a way that thermosetting coating composition, thermosetting acrylic resin, or cured unsaturated polyester resin remains at the deepest point of this indentation, and / or for creating gloss differences in the layer by a pressing element with gloss differences.

[0081] Prior to pressing, the use of a photoinitiator and UV radiation creates a surface to be pressed that is dry, or at least partially dry, for pressing. Drying may be necessary for various reasons during the production process, such as for ease of intermediate storage and / or stacking. This dry or semi-dry state can also be achieved through other methods. Several important possibilities are listed below.

[0082] Preferably, the coating composition used in the method comprises at least: an acrylic resin, one or more components containing free hydroxyl groups, one or more components containing free isocyanate groups, optionally one or more thermal initiators, optionally a photoinitiator, and optionally one or more crosslinking agents. The thermal initiators, photoinitiators, and crosslinking agents mentioned in other aspects of the invention can be used. Additionally, the coating composition may include hard particles as described in other independent aspects of the invention.

[0083] Preferably, the coating composition comprises hydroxyl-functional acrylates and / or hydroxyl-functional urethane acrylates.

[0084] Preferably, the coating composition comprises an isocyanate polymer and / or an isocyanate-functionalized acrylate.

[0085] Preferably, in the hot pressing of the method described above, a condensation reaction occurs between the hydroxyl and isocyanate groups of the coating composition, thereby generating crosslinks in the coating composition.

[0086] Preferably, after the step of applying the coating composition, acrylic resin or unsaturated polyester resin to the decorative layer; and before the step of at least partially curing the coating composition, acrylic resin or unsaturated polyester resin by hot pressing to form at least a portion of the wear-resistant layer, the method includes the step of removing water and / or solvent from the coating composition, acrylic resin or unsaturated polyester resin.

[0087] Preferably, after the step of applying the coating composition, acrylic resin, or unsaturated polyester resin to the decorative layer; and before the step of at least partially curing the coating composition, acrylic resin, or unsaturated polyester resin by hot pressing to form at least a portion of the wear-resistant layer; the method includes the step of gelling the coating composition, acrylic resin, or unsaturated polyester resin into a non-sticky state. An advantage of this embodiment is that it allows a non-sticky intermediate product to be obtained, for example, in a rolled-up state before hot pressing.

[0088] Preferably, the method comprises: a step of UV post-curing the pressed abrasion-resistant layer after hot pressing, wherein cross-linking of the double bonds occurs. For this purpose, the coating composition, acrylate resin, or unsaturated polyester resin preferably contains a photoinitiator. This UV curing is preferably carried out under an inert atmosphere.

[0089] Preferably, the method includes a step of post-curing the pressed abrasion-resistant layer after hot pressing, wherein cross-linking of the double bonds occurs. For this purpose, the coating composition, acrylate resin, or unsaturated polyester resin preferably contains a thermal initiator. Preferably, the post-curing after hot pressing is performed at a temperature higher than that of the hot pressing.

[0090] In a preferred embodiment of the method, prior to the step of applying the coating composition, acrylate resin, or unsaturated polyester resin, or a combination thereof, to the decorative layer, the method includes the step of applying an adhesion promoter to the decorative layer. Preferably, the adhesion promoter comprises one or more of polyurethane, polyurethane dispersion, water-based polyurethane dispersion, acrylate-functionalized polyurethane dispersion, melamine acrylate, or acrylate primer, or is composed of one or more of these. More preferably, a reactive, low-viscosity acrylate primer is used. Adhesion promoters such as those described in the first and / or second aspects of the invention can be used in the method of the third aspect of the invention.

[0091] Preferably, the coating composition, acrylic resin, or unsaturated polyester resin, or a combination thereof, is applied to the decorative layer by a wet or dry process.

[0092] When using a coating composition in the method described above, the coating composition preferably contains a solvent, such as butyl acetate. Using a coating composition containing a solvent has many advantages. If the coating composition is applied to a thermoplastic decorative layer, the solvent acts on this thermoplastic decorative layer. In this way, better adhesion to the decorative layer is obtained after the abrasion layer has cured. An example is the use of a decorative layer containing a thermoplastic film, such as polyvinyl chloride (PVC); and more preferably, a printed thermoplastic film, even more preferably, a printed thermoplastic polyvinyl chloride (PVC) film. An example is a decorative layer formed by pressing a thermoplastic substrate, wherein these thermoplastic substrates may contain fillers, such as wood fibers, or inorganic fillers, such as calcium, clay, or chalk. Such a thermoplastic substrate may contain polyvinyl chloride (PVC) or polyethylene or polypropylene as a thermoplastic plastic.

[0093] In a preferred method of pressing using a continuous press or hot rollers, the method preferably includes the step of applying a decorative layer to a substrate by spreading it from a roller, and this decorative layer is preferably a film made of synthetic material or a printed film or printed paper made of synthetic material – and preferably impregnated with a thermosetting resin. More preferably, the coating composition is placed on the decorative layer by a dry process via spreading it from a roller.

[0094] Preferably, the embossing is pressed into the wear-resistant layer after hot pressing, and the wear-resistant layer is post-cured by heat or by UV radiation after pressing the embossing. This implementation allows for high-quality decorative effects. The wear-resistant layer is partially heat-cured during hot pressing. However, the wear-resistant layer still exhibits sufficient plasticity to allow the embossing to be pressed into it in subsequent processing (whether or not it is in a hot state). Due to the plastic behavior of the wear-resistant layer, this can be done in the form of pressed embossing without creating any cracks in the wear-resistant layer. In the subsequent post-curing, for example by heat or by UV radiation, the wear-resistant layer is further cured, thus giving it its final properties. In this post-curing, UV radiation is preferred because it also allows for the effective curing of deep and narrow embossing layers. For example, this method also allows for the production of panels with a top layer that realistically simulates wood by pressing an embossing aligned with a printed wood pattern into the decorative layer. This invention also makes it possible to use thermoplastic substrates (such as substrates containing polypropylene, polyethylene, or polyvinyl chloride) regardless of whether the substrate has fillers such as wood fibers or wood particles or inorganic fillers such as calcium, clay, or chalk.

[0095] In a preferred method, the substrate comprises a thermoplastic, preferably PVC, polypropylene, or polyethylene. Preferably, this thermoplastic is filled with a filler. The decorative layer comprises a film made of a synthetic material, such as a polyvinyl chloride film, and more preferably, this film made of synthetic material is printed thereon. Alternatively, the decorative layer may comprise or consist of printing on the substrate.

[0096] In a preferred method, the substrate comprises or is composed of wood fiberboard (such as MDF or HDF); and the decorative layer comprises a printed carrier sheet, preferably printed paper. The carrier sheet is preferably impregnated with a thermosetting resin.

[0097] In addition, the method can be carried out according to several possibilities discussed below. When an acrylic resin is specified, these possibilities also apply to the use of coating compositions containing acrylic resins.

[0098] According to the first possibility, the acrylate resin or unsaturated polyester resin or coating composition is applied via a two-component varnish. This two-component varnish can be dried by physical curing, while the thermosetting acrylate component or thermosetting unsaturated polyester component is cured in hot pressing.

[0099] According to the second possibility, two thermal initiators with different SADTs (auto-accelerating decomposition temperatures) are used in acrylate resins or unsaturated polyester resins. Preferably, the lowest SADT is selected so that it is below the pressing temperature, and this thermal initiator can thus take effect before pressing or before activation by the other thermal initiator. Some drying can be achieved when activating the thermal initiator with the lowest SADT.

[0100] According to the third possibility, the acrylate resin is applied as a 100% solid substance together with a photoinitiator and a thermal initiator. The acrylate resin can then be gelled by UV radiation, resulting in some drying. The coated paper can then optionally be stored at a temperature below the SADT of the thermal initiator. Further or complete curing is then achieved in hot pressing. After pressing, further curing can optionally be performed by UV radiation.

[0101] According to the fourth possibility, an electric or water-based varnish containing both photoinitiators and thermal initiators can be used. This can be done in the same manner as the third possibility, with similar options for further curing after pressing.

[0102] According to the fifth possibility, a solvent-based acrylate resin or unsaturated polyester resin containing a thermal initiator and / or a photoinitiator is used. After applying the solvent-based resin, the solvent is evaporated at a low temperature. A non-sticky surface is then obtained. Curing is performed after pressing the panel, preferably with additional curing via UV radiation after pressing.

[0103] According to the sixth possibility, a dual-curing varnish is used, in which a combination of hydroxyl-functionalized acrylates is combined with isocyanate-functionalized acrylates. This varnish contains a photoinitiator and / or a thermal initiator. After solvent evaporation, the varnish is non-sticky, and curing is achieved through crosslinking of hydroxyl groups with isocyanate groups, accompanied by curing via two-carbon bonds.

[0104] According to the seventh possibility, an electric or water-based varnish can be used, primarily employing a thermal initiator to initiate a free radical reaction. The acrylic resin can then be gelled by hot air or (N)IR radiation. The coated paper can then optionally be stored at a temperature below the SDAT of the thermal initiator. Further or complete curing is then achieved in hot pressing. After pressing, if a photoinitiator is present, further curing can optionally be performed by UV radiation.

[0105] Depending on further possibilities, the various possibilities mentioned above can be combined in different partial layers, optionally with intermediate drying or gelling or partial curing.

[0106] Typically, in the context of this invention, it is preferable that the aforementioned thermosetting acrylate resin layer or thermosetting unsaturated polyester covers the entire surface of the flooring panel, optionally excluding reduced edge areas, for example, in the form of beveled or so-called chamfered edges. In this way, sufficient water resistance is imparted to the entire surface.

[0107] For the same purpose as the first to third aspects, according to a separate fourth aspect, the present invention also relates to a coated panel having at least a substrate and a top layer applied thereon, wherein the top layer comprises at least a decorative layer and a translucent or transparent abrasion-resistant layer, characterized in that the abrasion-resistant layer comprises an acrylate, wherein such acrylate comprises covalent bonds formed by the reaction of hydroxyl groups with isocyanate groups. The coated panel according to the fourth aspect of the invention can be prepared by the method of the third aspect of the invention, wherein an acrylate resin or a coating composition comprising an acrylate resin is used.

[0108] According to a fourth aspect of the present invention, in the coated panel, an adhesion promoter is located between the decorative layer and the abrasion-resistant layer. Preferably, the adhesion promoter comprises one or more of polyurethane, polyurethane dispersion, water-based polyurethane dispersion, acrylate-functionalized polyurethane dispersion, melamine acrylate, or acrylate primer (e.g., reactive low-viscosity acrylate primer), or is composed of one or more of these. In this case, adhesion promoters mentioned in other aspects of the present invention can be applied.

[0109] The coated panel according to the fourth aspect of the invention preferably includes an embossed pattern in the wear-resistant layer. More preferably, the embossed pattern displays a gloss difference.

[0110] Preferably, the coated panel according to the fourth aspect of the invention has a decorative layer that displays a wood pattern by printing, and the wear-resistant layer includes an embossed relief aligned with the wood pattern, and the embossed relief more preferably includes a gloss difference aligned with the wood pattern.

[0111] Preferably, the coated panel according to the fourth aspect of the invention comprises a substrate comprising a thermoplastic, such as polyvinyl chloride, polyethylene, or polypropylene. Preferably, this thermoplastic comprises one or more fillers, such as wood fibers, or inorganic fillers, such as calcium, clay, or chalk. The decorative layer comprises a film made of a synthetic material or a printed film made of a synthetic material, or the decorative layer comprises a print on the substrate.

[0112] Preferably, the coated panel according to the fourth aspect of the invention comprises a substrate comprising, or composed of, wood fiberboard (such as MDF or HDF). The decorative layer comprises a printed carrier sheet, preferably printed paper, and more preferably printed paper impregnated with a thermosetting resin.

[0113] It is clear that the method of the third aspect is preferably used for producing coated panels of the first and / or second and / or fourth aspects and / or their preferred embodiments.

[0114] It is clear that the coated panels obtained according to the first, second, or fourth aspects and / or according to the third aspect can exhibit different structures. Several important possibilities are listed below, but this list is not intended to be exhaustive.

[0115] According to the first possibility, the coated panel comprises a wood fiberboard as a substrate, printed paper provided with synthetic materials as a decorative layer, and the abrasion-resistant layer of the present invention. According to an important example, the printed paper comprises a polyurethane coating at least on the surface facing the abrasion-resistant layer. Preferably, the paper core is impregnated with a melamine-based resin (such as modified melamine resin). The polyurethane coating preferably has a König hardness of 50 to 70 seconds. The abrasion-resistant layer preferably exhibits trace amounts of benzene or toluene, or benzoyl peroxide or methyl benzoyl peroxide. Preferably, hard particles (e.g., corundum particles) are located on the printed paper. Preferably, the coated panel displays a structure or relief on its surface (more specifically in the abrasion-resistant layer) having a cross-section with a depth of 400 μm or more and / or a relief cross-section penetrating into the substrate.

[0116] According to the second possibility, the coated panel comprises a substrate composed of synthetic materials or synthetic composites (more specifically thermoplastics or thermoplastic composites). This can be, for example, a substrate based on filled PVC (polyvinyl chloride), PP (polypropylene), PET (polyethylene terephthalate), or PU (polyurethane). The filler can comprise calcium carbonate or talc or another powder or substance, such as wood chips, bamboo chips, and / or other plant components. In the case of PVC, it can be rigid, semi-rigid, or flexible PVC, specifically with a plasticizer content of less than 5, 5 to 15, or greater than 15 per 100 parts of PVC, respectively. The filler content can vary drastically and can be as high as 80 or 85% by weight of the composite material. The decorative layer can, for example, be comprised of printing disposed on a film made of synthetic materials (e.g., a PVC film). Then, according to the invention, the abrasion layer comprises at least a portion based on thermosetting acrylates or thermosetting unsaturated polyesters. Clearly, the abrasion-resistant layer may also include other components, such as a transparent film made of synthetic materials, like a transparent PVC film, which lies beneath a portion formed of thermosetting acrylate or thermosetting unsaturated polyester. This implementation allows for a clear embossed character and excellent surface properties on a panel primarily composed of thermoplastics.

[0117] According to a third possibility, the coated panel comprises a substrate that is at least partially cured together with a portion of a wear-resistant layer formed from a coating composition or an acrylic resin or an unsaturated polyester resin, and preferably also comprises a decorative layer. The substrate may be formed, for example, based on a textile layer, a woven layer, or a nonwoven layer (e.g., a so-called spunbond nonwoven layer), such as a textile layer based on glass fiber, steel fiber, etc., preferably provided with a thermosetting synthetic material (such as a thermosetting acrylic resin or a thermosetting unsaturated polyester). This third possibility of the coated panel can be formed in one step by pressing a stack of the textile layer, decorative layer, and wear-resistant layer provided with the synthetic material in a hot press. In this way, very thin but stable panels can be obtained, such as panels with a thickness of less than 4 mm or even 2 mm or less.

[0118] According to the fourth possibility, the coated panel comprises a substrate and a wear-resistant layer according to the invention, but the decorative layer is formed from the surface of the substrate. This is, for example, in decorative panel materials (e.g., wood panel materials), such as those used to apply the invention to solid wood parquet flooring or oriented strand board (OSB).

[0119] According to the fifth possibility, the top layer is formed in one of the first to seventh possibilities as described above, but the substrate is made of fiber cement board, magnesium oxide-based board, polyolefin-based board, wood chip board, OSB, filled soft PVC board, filled hard or rigid PVC board, foam board made of synthetic materials (preferably so-called closed-cell foam board made of synthetic materials), or multilayer board (such as multilayer board or synthetic material-based board with soft PVC layer and hard or rigid PVC layer).

[0120] With the same objective as the first to fourth aspects, according to a separate fifth aspect, the invention also relates to a coated panel having at least a substrate and a top layer applied thereon, wherein the top layer comprises at least a decorative layer, characterized by having a thermosetting acrylate resin or a thermosetting unsaturated polyester resin between the decorative layer and the substrate, and / or characterized by the decorative layer being at least partially formed of a thermosetting acrylate resin or a thermosetting unsaturated polyester resin. According to this fifth aspect, the coated panel thus does not necessarily have an abrasion-resistant layer. If this is indeed the case, such an abrasion-resistant layer is not necessarily based on a thermosetting acrylate resin or a thermosetting unsaturated polyester resin. The inventors have found that the presence of a thermosetting acrylate resin or a thermosetting unsaturated polyester resin at any location on the top layer can lead to improvements in click sound and other surface properties. Of course, the acrylate resin or polyester resin and / or thermal initiator used in the context of the fourth aspect can be the same as those discussed in the context of the first to fourth aspects, and it is understood that they do not necessarily result in a transparent or translucent layer.

[0121] Preferably, the decorative layer comprises at least a carrier sheet, such as paper, wherein a thermosetting acrylate resin or a thermosetting unsaturated polyester resin forms a bond between the carrier sheet and the substrate. It is clear that paper, as described above, can be used for this purpose.

[0122] Preferably, the thermosetting acrylate resin or thermosetting unsaturated polyester resin in the fourth aspect is configured to be colored, for example, because it contains pigments such as titanium dioxide. In this case, the invention may relate to a white panel that can be used, for example, as a furniture panel, or as a semi-finished product in a method of using a white layer as a printing substrate for further printing.

[0123] Preferably, a thermosetting acrylate resin or a thermosetting unsaturated polyester resin forms a base layer for printing, the base layer at least partially forming the decorative layer described above.

[0124] According to an alternative embodiment, the decorative layer described above is a finish, wherein the thermosetting acrylic resin or the non-thermosetting unsaturated polyester resin preferably extends from the outside of the finish and / or through pores, cracks, and other openings present in the finish. As mentioned above, the acrylic resin or polyester resin is preferably colored. In this way, the acrylic resin or polyester resin can form a colored filler on the surface of the finish at the locations of openings (such as nodules and cracks).

[0125] Against the backdrop of the aforementioned four aspects, it should also be noted that for the substrate, wood fiberboard, such as MDF or HDF boards, can be used. According to specific embodiments, wood fiberboard with low density is used, particularly with an average density of less than 750 kg / m³, or even 650 kg / m³ or lower. When using coated panels, primarily in floating installations where these panels are used as flooring panels, using such low-density boards helps to further improve noise, such as clicking sounds. The lower residual tensile stress in the panel surface in the aforementioned aspects partially makes the use of such low-density wood fiberboard possible. Specifically, the risk of tensile stress in the top layer causing the upper edge to pull upwards is limited. In prior art laminated panels, this phenomenon is typically prevented or limited by increasing the density of the board. With the top layer of the panels of this invention, this is no longer necessary.

[0126] According to specific implementation methods, the substrate used is free of unbonded formaldehyde or formaldehyde-free. For example, this could be a wood fiberboard bonded by pMDI adhesive (polymeric methylene diphenyl diisocyanate). In this case, if the top layer is also formaldehyde-free, for example, constructed primarily based on paper and thermosetting acrylate resins and / or polyurethane, a completely low-formaldehyde or formaldehyde-free coated panel is obtained.

[0127] Furthermore, it should be noted again that, according to all its individual aspects, the present invention allows the aforementioned top layer to include a waterproof layer. This is possible because, unlike melamine-formaldehyde, thermosetting acrylate resins or thermosetting unsaturated polyester resins do not produce any so-called "chemical" water as a byproduct during polymerization. In the case of melamine resin being pressed or cured, it is important that this chemical water can escape to the substrate or surface, and in this case, the waterproof layer is an obstacle to be avoided. Preferably, the aforementioned waterproof layer is formed by a layer existing between the aforementioned decorative layer and the substrate. In this way, any moisture present on the surface of the coated panel cannot penetrate into the substrate, and a dimensionally stable panel can be obtained under conditions of humidity changes. This is important, for example, when the aforementioned substrate comprises or is composed of wood fiberboard. According to another possibility, the aforementioned waterproof layer is formed by an ink layer that at least partially forms the aforementioned decorative layer. Other examples of waterproof layers are TPU (thermoplastic polyurethane) films, polyester base layers, aluminum foil (especially non-porous aluminum foil), etc. According to all these embodiments, the dimensional stability of the coated panel can be increased.

[0128] Generally, it should be noted that, according to all its individual aspects, the present invention can be applied in a particularly useful manner to coated panels on which the decorative layer comprises printing with UV-curable inks. As described in WO 2014 / 024100, UV-curable inks can form a strong barrier against the chemical water from the aforementioned melamine polycondensation reaction, which can lead to various adverse effects on the panel surface. The present invention prevents or limits the formation of chemical water by using a thermosetting acrylic resin in the top layer.

[0129] It is clear that, in the context of this invention, the wear-resistant layer is considered to be the entire layer between the printed decorative layer and the panel surface. Furthermore, it is clear that this wear-resistant layer is preferably constructed substantially or even entirely using the aforementioned thermosetting acrylic resin or thermosetting unsaturated polyester resin or cured coating composition containing acrylic resin. It is also not excluded that the wear-resistant layer on the panel surface comprises another outer coating and / or that a portion of the wear-resistant layer is formed from a synthetic material of the carrier sheet initially applied to the aforementioned decorative layer.

[0130] According to a particular embodiment, the aforementioned abrasion layer comprises a sheet of material, such as paper. This sheet of material significantly contributes to the impact resistance of the flooring panel and reduces the risk of breakage in the typically hard but brittle abrasion layer. The sheet of material also makes the abrasion layer more resilient, which is important in subsequent processing of the flooring panel edges. The resilience of the abrasion layer reduces the risk of edge breakage during milling of optional connecting mechanisms. Furthermore, this sheet of material forms a barrier to prevent any abrasion-resistant or hard particles from entering the still-wet abrasion layer during production, making these particles more effective in the resulting flooring panel. According to its most preferred embodiment, the abrasion layer comprises a sheet of material that itself contains embedded hard particles. For example, this could be a so-called Mead layer, such as described in US 5,820,937, in which α-cellulose paper is filled with alumina particles or other abrasion-resistant particles during its production. In this embodiment, the hard particles are specifically held in a fixed position within the thickness of the abrasion layer, and no special measures are required to suspend the hard particles in the lacquer layer or other materials of the abrasion layer. The latter reduces the risk of transparency loss caused by the addition of any suspending agent and makes the production process smoother. Similarly, in edge processing, the risk of hard particles falling off is lower because these hard particles are held together to some extent within the material sheet.

[0131] As described above, the coated panel of the present invention is preferably a panel, particularly a floor panel intended for floating installation. Preferably, a further feature of the floor panel is that it is provided with mechanical connecting components at at least two opposing edges, and when two such floor panels are joined, these connecting components provide a clamping effect at the edge locations, where the upper edges (particularly the abrasion layer) abut against each other. Using this embodiment, reliable edge watertightness can be obtained. This is important, for example, when using porous and / or wood-based substrates, such as MDF or HDF.

[0132] According to a particular embodiment, the substrate is coated or impregnated at at least two opposing edges to prevent or limit moisture penetration into the substrate. In the case of a coating, the coating is preferably configured to overlap with the edge of the top layer. According to this embodiment, in other words, a moisture-proof coating is provided at the edge of the floor panel, wherein the coating extends from the substrate at least at the boundary with the top layer. Preferably, the coating extends further, particularly at least at the boundary with the decorative layer and / or the abrasion layer.

[0133] When applying low-density wood fiberboard (especially with a density of less than 750 or 650 kg / m³) to floor panels with mechanical linkages, it is preferable to take measures to improve the material quality at the edges of the substrate. For example, the edges can be reinforced or impregnated with MDI or PU. Another possibility is to apply an acrylic resin to these edges, which can then be cured, preferably by electron beam radiation. This curing can optionally be achieved together with the aforementioned UV or electron beam post-curing. Preferably, the acrylic resin applied to the edges is a viscous acrylic resin. Yet another possibility is to apply urea-formaldehyde (UF), melamine-formaldehyde (MF), or another resin to at least press it into the location where the linkage will ultimately form. Alternatively, the substrate can be impregnated with PU or MDI from the bottom surface. In most existing click systems, such as those of WO97 / 47834, it is important to ensure stability, especially in the lowermost area of ​​the board, particularly where the lowermost groove lip of the lockable tongue and groove joint is located.

[0134] As described above, the wear-resistant layer preferably has a structure or relief formed by indentation on its surface. Preferably, this structure helps to mimic the pattern depicted in the printed decorative layer and / or the structure forms the boundary of the printed decorative layer, for example, on at least one edge. For example, in the case of imitation wood, indentations in the form of wood pores and / or leaf veins can be used. According to another example, the decorative layer can be demarcated in the form of bevels or other edges. In the case of stone decoration, a structure mimicking existing mortar joints can be used. As described above, the present invention makes it possible to form such a structure or relief with deep indentations, for example, indentations 400 μm or deeper. For example, bevels or other edges with a depth of 400 μm can be formed.

[0135] Preferably, the wear-resistant layer is provided with structural components that penetrate into the substrate, or in other words, both the decorative layer and the underlying substrate are structured. This implementation is particularly interesting in the implementation of structural components such as edges, because in this way, even with a limited thickness, the wear-resistant layer can be given a deeper texture. The embossing achieved in the decorative layer itself also contributes to the realistic imitation of the panel.

[0136] As described above, in structures or reliefs with deep indentations and / or in structural components that penetrate into the substrate, it is preferable to provide a sufficiently fluid thermosetting acrylate resin, for example by selecting benzoyl peroxide or methyl benzoyl peroxide as a thermal initiator.

[0137] According to a variation, based on one or more of the foregoing aspects of the invention, the present invention relates to decorative profiles rather than coated panels. For example, this could be a type of profile used for finishing floor coatings, such as transition profiles, final profiles, skirting boards, etc. This variation provides for the smooth production of profiles suitable for decorative panels, particularly those coated panels. According to this variation, the invention can lead to the simpler production of floor-quality decorative profiles, thereby creating greater freedom in the design of such profiles.

[0138] Acrylic resins used in different aspects of the present invention may, for example, have the following composition:

[0139] -5 to 80% by weight of monomer, or more preferably 5 to 60% by weight, said monomer may be monofunctional, difunctional or polyfunctional, preferably selected from cyclic monofunctional monomers (CTFA (cyclotrimethylolpropane acetal acrylate), TMCHA (trimethylcyclohexyl acrylate), TBCHA (4-tert-butylcyclohexyl acrylate), IBOA (isobornyl acrylate), THFA (tetrahydrofurfuryl acrylate), etc.), alkoxylated monofunctional monomers (PE4A, etc.), alkane monofunctional monomers (EOEOEA (2-(2-ethylhexyl acrylate)...). Oxyethyl ethoxylate), alkoxylated bifunctional monomers, alkyl bifunctional monomers, polyfunctional monomers (TMPTA (trimethylolpropane triacrylate), GPTA (propoxylated glycerol triacrylate), PET(T)A (pentaerythritol tri(tetra)acrylate), etc.), acid-based adhesive promoter monomers; preferably mono-, di-, or polyfunctional acrylate or methacrylate monomers, preferably trifunctional, in order to limit the risk of generating unpleasant odors; as a specific example, TMPTMA (trimethylolpropane trimethacrylate) can be used;

[0140] -0.1 to 10% by weight of additives, such as defoamers and leveling agents; preferably 0.1 to 2% by weight of leveling agents and / or 0.1 to 2% by weight of defoamers; as a leveling agent, silicone polyether acrylate, such as TEGORad 2300, can be used; as a defoamer, BYK 1790 can be used.

[0141] -0.1 to 30% by weight, more preferably 1 to 10% by weight, of nano-silica or corundum (Al2O3); for example, a dispersion of colloidal (nano)silica in a monomer (such as a bifunctional acrylate monomer), or a dispersion of (nano)silica in butyl acetate or methoxypropyl acetate, or alumina flakes, such as alumina flakes with a particle size distribution between 3 and 18 μm, may be used.

[0142] -5 to 80% by weight of oligomers of unsaturated polyesters, polyester acrylates, urethane acrylates, polyether acrylates, melamine acrylates, polycarbonate acrylates, epoxy acrylates, amine-modified acrylates, or urethane (meth) acrylates, preferably 2 to 10 functional urethane (meth) acrylates and / or urethane acrylates of the formula AIPIA, wherein

[0143] • A: Acrylic acid or methacrylic acid, monofunctional or polyfunctional

[0144] • I: Isocyanates (aliphatic monomers or oligomeric di or polyfunctional)

[0145] • P: Polyols, long or short chain polyesters, polyethers, polycarbonates, bifunctional or polyfunctional;

[0146] -Optional, fillers, pigments and / or reinforcing agents;

[0147] -0.1 to 5% by weight of thermal initiator, preferably an organic peroxide or an azo polymerization initiator;

[0148] -Optionally, 0.1-5% by weight of photoinitiator;

[0149] -Optionally, 0.1-5% by weight of a crosslinking agent, such as isocyanate, carbodiimide and / or aziridine.

[0150] It should also be noted that the use of urethane acrylates has the added advantage of enabling hydrogen bridging, which results in a favorable flexibility-to-hardness ratio of the obtained layer. They can also be used in conjunction with or in addition to so-called "special high-functionality urethane acrylates," such as those using silicone-based hydrophilic functional or fluorinated acrylates.

[0151] Optionally, the above-described composition, or the acrylate resin to be cured, or the cured saturated polyester, may also contain a photoinitiator, for example, 0.1 to 10% by weight, preferably 1 to 10% by weight. These can be photoinitiators such as hydroxyacetophenone, acetophenone, aminoacetophenone, phosphine oxide, benzophenone, thioxanthone, benzoyl carbamate, or polymeric photoinitiators. These can be, for example, benzophenone or phosphine oxide, such as diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide. Such compositions may further contain an amine synergist, for example, 1 to 10% by weight. This synergist promotes UV curing. The presence of the photoinitiator allows for additional UV curing after thermal curing, such as after hot pressing, thereby applying the structure to the layer containing the acrylate resin (e.g., an abrasion layer). According to another possibility, the photoinitiator can be used to gel the acrylate resin or unsaturated polyester resin, thereby enabling thermal curing. For example, before incorporating a carrier sheet (such as printed paper or decorative paper) into the stack to be pressed, an acrylic resin or unsaturated polyester resin can be gelled onto such a carrier sheet. This gelling can also be used to apply a backing layer to the underside of a substrate.

[0152] Additionally, the above composition may optionally contain a UV absorber, for example, 0.1 to 5% by weight, preferably 1 to 2% or 1.5%. As a UV absorber, 2-hydroxyphenyl-s-triazine may be used, which may contain 15-25% of 2-methoxy-1-propyl acetate (e.g., BASF Tinuvin 477), or bis(1,2,2,6,6-pentamethyl-4-piperidinyl sebacate) containing methyl sebacate 1,2,2,6,6-pentamethyl-4-piperidinyl sebacate (e.g., BASF Tinuvin 292).

[0153] Further optional components of the above composition are matting agents, such as fumed silica (whether or not treated with wax), precipitated silica, or micronized condensation organic polymers. For example, 0.1 to 8% by weight of such a matting agent can be used. Practical examples of suitable matting agents are Evonik Acematt 3600 and PQ Gasil UV55C. Additionally, optional components of the above composition are cleaning-promoting additives, anti-slip additives, and antibacterial additives. Detailed Implementation

[0154] Several examples of possible compositions are listed below:

[0155] Example 1 - Wet process single thermosetting

[0156] • 10-40%, preferably 20%, of hexafunctional aliphatic carbamate acrylates

[0157] • 30-80%, preferably 60%, of bifunctional aliphatic carbamate acrylates

[0158] • 5-40%, preferably 18%, of the bifunctional monomer dipropylene glycol diacrylate (DPGDA)

[0159] • 0.1-5%, preferably 0.5-5%, more preferably 1% of TBPIN thermal initiator, namely tert-butylperoxy-3,5,5-trimethylhexanoate.

[0160] • 0.5-1.5%, preferably 1% leveling agent

[0161] Example 2 - Wet process single thermosetting

[0162] • 10-40%, preferably 20%, of hexafunctional aliphatic carbamate acrylates

[0163] • 30-80%, preferably 40%, of bifunctional aliphatic carbamate acrylates

[0164] • 5-40%, preferably 20% trifunctional epoxy acrylate

[0165] • 5-40%, preferably 18%, of the bifunctional monomer dipropylene glycol diacrylate (DPGDA)

[0166] • 0.1-5%, preferably 0.5-5%, more preferably 1% TBPIN thermal initiator

[0167] • 0.5-1.5%, preferably 1% leveling agent

[0168] Example 3 - Wet process single thermosetting

[0169] • 10-40%, preferably 20%, of hexafunctional aliphatic carbamate acrylates

[0170] • 30-80%, preferably 40%, of bifunctional aliphatic carbamate acrylates

[0171] • 5-40%, preferably 20% trifunctional epoxy acrylate

[0172] • 5-40%, preferably 18% of the trifunctional monomer (GPTA-propoxylated glycerol triacrylate)

[0173] • 0.1-5%, preferably 0.5-5%, more preferably 1% TBPIN thermal initiator

[0174] • 0.5-1.5%, preferably 1% leveling agent

[0175] Example 4 - Wet process single thermosetting

[0176] • 10-40%, preferably 20%, of hexafunctional aliphatic carbamate acrylates

[0177] • 30-80%, preferably 40%, of trifunctional aliphatic urethane acrylate, i.e., containing additional isocyanate groups (isocyanate groups) for “instant dual curing”.

[0178] • 5-40%, preferably 20% trifunctional epoxy acrylate

[0179] • 5-40%, preferably 18%, of the bifunctional monomer dipropylene glycol diacrylate (DPGDA)

[0180] • 0.1-5%, preferably 0.5-5%, more preferably 1% TBPIN thermal initiator

[0181] • 0.5-1.5%, preferably 1% leveling agent

[0182] Example 5 - Wet process single thermosetting

[0183] • 10-40%, preferably 20%, of hexafunctional aliphatic carbamate acrylates

[0184] • 30-80%, preferably 50%, of bifunctional aliphatic carbamate acrylates

[0185] • 5-30%, preferably 10% silicone acrylates (2 to 6 functionalities), namely "special high-functionality urethane acrylates" to enhance cleanliness.

[0186] • 5-40%, preferably 18%, of the bifunctional monomer dipropylene glycol diacrylate (DPGDA)

[0187] • 0.1-5%, preferably 0.5-5%, more preferably 1% TBPIN thermal initiator

[0188] • 0.5-1.5%, preferably 1% leveling agent

[0189] Example 6 - Wet process single thermosetting

[0190] • 10-40%, preferably 20%, of hexafunctional aliphatic carbamate acrylates

[0191] • 30-80%, preferably 50%, of bifunctional aliphatic carbamate acrylates

[0192] • 2-15%, preferably 10%, of nano-silica dispersed in TMPTA monomer; this results in increased scratch resistance.

[0193] • 5-40%, preferably 18%, of the bifunctional monomer dipropylene glycol diacrylate (DPGDA)

[0194] • 0.1-5%, preferably 0.5-5%, more preferably 1% TBPIN thermal initiator

[0195] • 0.5-1.5%, preferably 1% leveling agent

[0196] Example 7 – Wet process using gelling – or completely dry process

[0197] The same formulation as in Examples 1 to 6 can be used, but with an additional 0.1-5% (and preferably 0.5-5%) of a photoinitiator, such as benzophenone, 1-hydroxycyclohexylphenyl ketone, XBPO (phosphine bis(2,4,6-trimethylbenzoyl)), TPO (C 22 H 21P O2) or ITX (isopropylthioxanthone). A mixture of photoinitiators is not excluded and is even expected, in which one photoinitiator is used to cure the surface and the other is used to deeply cure the paint.

[0198] According to another practical embodiment, the thermosetting acrylate resin consists of the following components:

[0199] -53.7 parts aliphatic carbamate acrylate;

[0200] -0.3 parts benzoyl peroxide;

[0201] -46 parts dipropylene glycol diacrylate;

[0202] -Optional defoamers, leveling agents, nano silica and / or corundum (Al2O3).

[0203] Example 8 – Wet process using gelling (solvent-based) – Coating composition comprising the following components (all in % or parts by weight).

[0204] • 100 portions of component A, the composition of which is:

[0205] 40-90% hydroxyl-functionalized acrylates, in butyl acetate as solvent (30-60% solvent),

[0206] 0.01-1% of a crosslinking agent, such as an organometallic compound, like dibutyltin dilaurate or zinc neodecanoate.

[0207] 0.1-5% photoinitiator,

[0208] 0.1-2% UV absorber,

[0209] 0.1-2% light stabilizer,

[0210] 5-40% mono-, di-, tri-, or tetrafunctional acrylate monomers

[0211] • 5-20 parts isocyanate, such as aliphatic polyisocyanate.

[0212] Example 9 – Wet process using gelling (solvent-based) – Coating composition comprising the following components (all in % or parts by weight).

[0213] • 30-70 parts of component A, the composition of which is:

[0214] 40-90% hydroxyl-functionalized acrylates, in butyl acetate as solvent (30-60% solvent),

[0215] 0.01-1% of a crosslinking agent, such as an organometallic compound, like dibutyltin dilaurate or zinc neodecanoate.

[0216] 0.1-5% photoinitiator,

[0217] 0.1-2% UV absorber,

[0218] 0.1-2% light stabilizer,

[0219] 5-40% mono-, di-, tri-, or tetrafunctional acrylate monomers

[0220] • 30-70 parts of isocyanate-functionalized acrylate in solvent

[0221] Example 10 – Wet process using gelling (solvent-based) – Coating composition comprising the following components (all in % or parts by weight).

[0222] • 50-90 parts of component A, whose composition is:

[0223] 40-90% hydroxy-functionalized urethane acrylates, in butyl acetate as solvent (30-60% solvent),

[0224] 0.01-1% of a crosslinking agent, such as an organometallic compound, like dibutyltin dilaurate or zinc neodecanoate.

[0225] 0.1-5% photoinitiator,

[0226] 0.1-2% UV absorber,

[0227] 0.1-2% light stabilizer,

[0228] 5-40% mono-, di-, tri-, or tetrafunctional acrylate monomers

[0229] • 10-50 parts of isocyanate-functionalized acrylate in solvent

[0230] Example 11 - Wet process single thermosetting

[0231] • 10-80%, preferably 50% unsaturated polyester

[0232] • 10-50%, preferably 20% tetrafunctional polyester acrylate

[0233] • 5-40%, preferably 18%, of the bifunctional monomer dipropylene glycol diacrylate (DPGDA)

[0234] • 0.1-5%, preferably 0.-5%, more preferably 1% TBPIN thermal initiator

[0235] • 0.5-1.5%, preferably 1% leveling agent

[0236] Example 12 - Wet process single thermosetting

[0237] • 10-80%, preferably 50% unsaturated polyester

[0238] • 10-50%, preferably 20% tetrafunctional polyester acrylate

[0239] • 2-20%, preferably 10%, of 10-functional aliphatic carbamate acrylates

[0240] • 5-40%, preferably 15% of the bifunctional monomer dipropylene glycol diacrylate (DPGDA)

[0241] • 1-8%, preferably 3% alumina

[0242] • 0.1-5%, preferably 0.-5%, more preferably 1% TBPIN thermal initiator

[0243] • 0.5-1.5%, preferably 1% leveling agent

[0244] Example 13 – Using a wet process with gelation – or a completely dry process

[0245] The same formulation as in Examples 1 and 2 can be used, but with an additional 0.1-5% of a photoinitiator, such as benzophenone, 1-hydroxycyclohexylphenyl ketone, XBPO (phosphine bis(2,4,6-trimethylbenzoyl)), TPO (C 22 H 21P O2) or ITX (isopropylthioxanthone). The addition of a mixture of photoinitiators is not excluded and is even expected, one photoinitiator for curing the surface and the other for deep curing the paint.

[0246] To better explain the features of the present invention, several preferred embodiments are described below with reference to the accompanying drawings, but in no way are they intended to be limiting, wherein:

[0247] Figure 1 A perspective view of a coated panel (more specifically a floor panel) having the features of the present invention is shown;

[0248] Figure 2 It shows along Figure 1 The larger proportion of the cross section of line II-II;

[0249] Figure 3 This is a schematic diagram of multiple steps in a method having the features of the present invention;

[0250] Figure 4 and Figure 5 The sound measurement results of the panel having the features of the present invention are shown; and

[0251] Figure 6 A method having the features of the present invention is shown.

[0252] Figure 1 A coated panel 1 is shown. In this case, it is a rectangular floor panel comprising a base 2 and a top layer 3 applied thereon, the top layer 3 having at least a decorative layer 4 and a translucent or transparent abrasion layer 5. The abrasion layer 5 comprises a thermosetting acrylic resin, wherein curing is achieved through a thermally initiated free radical crosslinking reaction. For this purpose, the starting point is a mixture of acrylic resin and a thermal initiator. The abrasion layer may also comprise a cured polyester resin or a cured coating composition containing acrylic esters.

[0253] The floor panel 1 is suitable for floating installation, and for this purpose, mechanical coupling mechanisms 10 are provided on both the long pair of edges 6-7 and the short pair of edges 8-9, which allow two such floor panels 1 to be connected to each other at the respective edges 6-7-8-9.

[0254] Figure 2 This makes it clear once again that Figure 1 The floor panel 1 has at least one long opposite side ratio 6-7 with a mechanical connection mechanism 10, mainly in the form of teeth 11 and grooves 12, wherein when two such floor panels 1 are joined on these edges 6-7, there is a locking between the teeth 11 and grooves 12 on a first direction R1 perpendicular to the surface 13 of the joined panel 1 and on a second direction R2 perpendicular to the joined edges 6-7 and in the plane 13 of the panel 1.

[0255] Preferably, on the short edge 8-9, as in Figure 1 and 2In some implementations, a mechanical coupling mechanism 10 is also provided, which provides locking in the respective direction, whether or not primarily in the form of teeth 11 and slots 12.

[0256] for Figure 2 In this embodiment, a substrate 2 comprising wood fiberboard with a density of 750 kg / m³ or less is used. To improve the bonding strength of the connecting mechanism 10, the edges 6-7 of the substrate 2 are impregnated with MDI (methylene diphenyl diisocyanate) 14. As mentioned above, it is important that the lowermost lips 15 located on both sides of the groove 12 are constructed sufficiently robust. To limit swelling that may occur during the milling of the connecting mechanism 10 due to penetration and / or printing effects, it is also desirable to reinforce the substrate material 2 by impregnation or other means near the upper edge 16.

[0257] In this example, a backing layer 18 is also provided on the lower side 17 of panel 1. This is preferably done on a thermosetting acrylic resin and its main purpose is to form a barrier against the rise of moisture. As described in the invention, the residual stress of the abrasion layer 5 is low, so the backing layer 18 only serves as a minimal balancing layer. Therefore, the backing layer 18 can also be omitted, especially when the substrate 2 itself is composed of a waterproof material and / or has a waterproof lower side 17 and / or is treated to have some degree of hydrophobicity at least on the lower side 17 of the substrate 2, for example, when the substrate material is impregnated with MDI on the lower side 17.

[0258] Figure 1 and 2 The decorative layer 4 of the floor panel 1 comprises a carrier sheet provided with synthetic material 19, and more specifically, has a surface weight of approximately 70 g / m². 2 Paper 20. Paper 20 shows a print 21 in the form of a wood-based graphic. The synthetic material 19 used contains double carbon bonds, more specifically polyurethane.

[0259] Figure 3 It was given again Figure 1 and 2 A schematic diagram of several steps in the manufacturing process of the floor panel.

[0260] In this example, the decorative layer 4, which includes at least paper 20, is considered as a reference. Paper 20 itself has printing 21. In the first step S1, paper 20, more specifically, the paper web subsequently obtained by cutting, is provided with a synthetic material 19. For this purpose, the paper web is unrolled and immersed in a core using the first synthetic material 19. Core immersion limits the risk of paper 20 splitting in the final coated panel 1. In this example, this core immersion is performed in two steps: specifically, in the first step S1A, the synthetic material 19 is applied by means of roller 22, and in the second step S1B, the paper 20 is immersed in a bath 23 containing the synthetic material 19. In this example, the synthetic material 19 applied in the first step S1A and the second step S1B is the same. However, the synthetic materials used in the first and second steps can also be different from each other, independent of the specific application technique used. Between the first step S1A and the second step S1B, the paper 20 follows a trajectory 24 that allows the first synthetic material 19 applied during the first step S1A to fully penetrate. As mentioned in the introduction, modified melamine-formaldehyde resin, modified urea-formaldehyde resin, or modified melamine-urea-formaldehyde resin can be used as the first synthetic material 19. Preferably, the first synthetic material 19 comprises double carbon bonds. Preferably, the first synthetic material 19 is selected from polyurethane, urethane-acrylic copolymer, acrylate, latex, and dispersions functionally combined with acrylate.

[0261] Figure 3 Further, following the core impregnation described above, for example, in this case, alumina particles can be applied in the third step S1C by a scattering treatment. Preferably, drying is then performed in a hot air oven 25 in the fourth step S1D. Optionally, in the fifth step S1E, an interlayer coating 26 can be applied on one side of the print 21 and / or on the side of the paper 20 intended to face the abrasion layer 5, which increases compatibility with the abrasion layer 5 to be formed from a thermosetting acrylate resin or a thermosetting unsaturated polyester resin or a coating composition containing an acrylate resin. For example, such an interlayer coating can consist of a water-based polyurethane coating, a water-based UV-curing substance, or melamine acrylate or reactive acrylate monomers. During the same step S1E or in a separate step, a coating 27 can also be applied on the side of the paper 20 intended to face the substrate 2. The purpose of this coating 27 is to provide better adhesion to the substrate 2. According to another possibility, this coating 27 can also be used to provide noise damping. In the latter case, polyurethane, such as aromatic polyurethane or thermoplastic polyurethane (TPU), is preferred. After applying interlayer coating 26 and / or coating 27, as in this example, a drying process similar to the fourth sub-step S1D can be performed again.

[0262] In the seventh sub-step S1F, in this example, the processed paper 20 passes through the cooling roller 28, and the paper web is divided into sheets.

[0263] In the second step S2, the formed stack 29 includes at least a substrate 2 and a decorative layer 4, wherein in this case, the decorative layer 4 includes the printed paper 20 provided with the synthetic material 19 obtained in step S1.

[0264] The method of the present invention includes at least: the third step S3 shown, specifically the step of applying an acrylic resin (or unsaturated polyester resin or a coating composition containing an acrylic resin) comprising a thermal initiator to the decorative layer 4, and the fourth step S4 shown, specifically the step of curing the resin by at least one step of hot pressing. In the third step S3, an acrylic resin having a thermal initiator is applied to the underside of the substrate 2 to form a backing layer 18. It is clear that in this case, the third step S3, specifically the step of applying resin to the decorative layer 4, is performed when the decorative layer 4 is already part of a stack 29 comprising at least the substrate 2 and the decorative layer 4.

[0265] In the example shown, pressing is performed by a so-called short-cycle press 30, and more specifically by a structured pressing element 31 or pressing plate. Pressing is performed on a stack 29 comprising an acrylic resin substrate 2, a decorative layer 4, a wear-resistant layer 5, and a backing layer 18. During pressing, the structure 32 of the pressing element 31 is imprinted on the surface of the wear-resistant layer 5.

[0266] Figure 4 The noise measurement results, shown by curves 33-34, are illustrated on a melamine surface of a prior art flooring panel (curve 33) and on a thermosetting acrylic surface of a flooring panel according to the invention (curve 34). These are curves showing the relationship between the measured loudness (in cubic meters) of the scratch noise (shown on the vertical axis 35) and the frequency (Hz) (shown on the horizontal axis 36), which was generated on this surface using a metal pin. Loudness is a variable that objectively reflects the level of noise as subjectively experienced. In the results for the melamine surface shown in curve 33, a very large and broad peak can be found in the frequency range of 1000 to 5000 Hz, where the human ear is most sensitive. The user would find this noise annoying. When the same scratch is performed on the thermosetting acrylic surface, the results of curve 34 show a significant decrease in absolute loudness over the same time interval. This results in a perceived warmer and less loud noise, equivalent to the noise generated on a wooden surface.

[0267] Figure 5The results of loudness measurements, shown by curves 37-38, are illustrated. These measurements were performed, on one hand, on a melamine surface of a prior art flooring panel (curve 37), and on the other hand, on a thermosetting acrylic surface of a flooring panel according to the invention (curve 38). Prior art flooring panels comprise an HDF substrate, particularly wood fiberboard with an average density of approximately 950 kg / m³. The flooring panel according to the invention comprises an MDF substrate, more particularly with an average density of approximately 650 kg / m³. 3 The wood fiberboard. The results are a curve showing the relationship between the loudness (in cubic meters) of the click sound (displayed on the vertical axis 35) and the frequency (Hz) (displayed on the horizontal axis 36) on this surface, where the click sound was generated using metal pins. The results show that the click sound on the floor panel of the present invention is not very loud and the peak disappears within an interval of 1000 to 5000 Hz. This achieves a warmer and more wood-like noise.

[0268] Figure 6 Another aspect of producing a coated panel 1 having the features of the present invention is shown. In this case, it is a method for producing a floor panel 1 having a substrate 2 of a synthetic material or a composite of synthetic materials, such as an LVT (luxury vinyl tile) type floor panel comprising a substrate 2 of highly filled soft, semi-rigid, or rigid PVC. The substrate 2 can be formed by extruding the synthetic material or the composition, or in this case, in the first step T1, the substrate 2 can be formed by one or more scattering operations (where particles 39 or powder having a suitable composition are deposited on a conveyor belt 40 and consolidated between belts 41 of a double-belt press). In the second step T2, a printed film made of synthetic material 24 can be spread onto the formed substrate 2 to form a decorative layer 4, and in the third step T3, a translucent film made of synthetic material 43 can optionally be spread to form at least a portion 5A of the wear-resistant layer 5. In the fourth step T4, a mixture of at least acrylic resin and a thermal initiator is applied, for example, by one or more rollers 44, to the obtained whole, preferably to the translucent film made of synthetic material 43. Then, in step T5, the substrate 2, one or more films made of synthetic materials, and a mixture of acrylate resin and thermal initiator are consolidated or cured by a hot roller 45. In the example shown, a structured roller is used. Ultimately, the structure 32 of the roller 45 is advantageously replicated in the thermosetting acrylate resin. This method results in a durable layer 5 with excellent aesthetic and mechanical properties, without requiring an additional surface UV-cured varnish layer as is required for existing LVT floor panels.

[0269] As Figure 6An alternative to the method shown can be to apply a mixture of acrylate resin and thermal initiator to a semi-finished product (whether or not solidified), which comprises a substrate of synthetic material or a composite of synthetic materials and at least a decorative layer, for example, applied to a semi-finished product having a substrate, a printed film made of synthetic material, and optionally a transparent film made of synthetic material on the printed surface. Then it can be combined with... Figure 3 The entire semi-finished product and mixture are pressed in a short-cycle press similar to the press 30 shown in step S4.

[0270] It is clear that the methods shown and mentioned in the introduction can be performed entirely or partially on a large panel, plate, or continuous web. In this case, the actual coated panel is obtained after separating the panel, plate, or web at least once.

[0271] This invention is by no means limited to the embodiments described above; rather, such coated panels and their manufacturing methods can be realized without departing from the scope of this invention. Furthermore, the concept of this invention can also be applied to textured packaging materials or flat materials, such as posters, stationery, or laminated materials for laminated profiles, such as baseboards and decorative profiles for flooring. Therefore, this invention also relates to a method for producing packaging materials or flat materials, characterized in that the method comprises the steps of: applying a heat-curable acrylate resin or a heat-curable unsaturated polyester (e.g., having a thermal initiator) to the actual packaging material or flat material (e.g., paper, cardboard, a film made of synthetic material, synthetic material), and at least partially curing the aforementioned acrylate resin or unsaturated polyester by hot pressing, wherein a structured pressing element or a pressing film is preferably used. It is clear that this method can further exhibit the preferred features of the invention according to the third aspect, without obtaining a coated panel.

Claims

1. Coated panel having at least a substrate (2) and a top layer (3) applied thereon, wherein the top layer (3) comprises at least a decorative layer (4) and a semi-transparent or transparent wear layer (5), wherein the wear layer (5) comprises a thermally cured acrylate resin or a thermally cured unsaturated polyester resin, wherein the thermally curing cures the acrylate resin or the unsaturated polyester resin partially or completely, wherein the wear layer (5) is obtained on the basis of a mixture comprising at least on the one hand an acrylate resin or an unsaturated polyester resin, and on the other hand a thermal initiator, wherein the substrate comprises a thermoplastic substrate, wherein the decorative layer comprises a printed film made of synthetic material, or wherein the decorative layer comprises a print on the substrate, wherein the thermal curing comprises a hot-pressing operation in which the coated panel is provided with a relief on its surface, wherein the wear layer (5) is present above the decorative layer (4).

2. Coated panel according to claim 1, wherein the wear layer (5) is obtained on the basis of a mixture comprising at least on the one hand an acrylate resin or an unsaturated polyester resin, and on the other hand a thermal initiator and a photoinitiator.

3. Coated panel according to claim 1, wherein the thermoplastic of the thermoplastic substrate is chosen from the group consisting of polyvinyl chloride, polyethylene or polypropylene.

4. Coated panel according to claim 1, wherein the thermoplastic substrate comprises one or more fillers.

5. Coated panel according to claim 1, wherein a semi-transparent film made of synthetic material is provided between the decorative layer and the thermally cured acrylate resin or the thermally cured unsaturated polyester resin.

6. Coated panel according to claim 1, wherein the thermal curing comprises a chemical crosslinking of double bonds present in the acrylate resin or in the unsaturated polyester resin.

7. Coated panel according to claim 1, wherein the wear layer comprises a thermally cured acrylate resin, and wherein the acrylate resin is obtained at least on the basis of multifunctional acrylate monomers and oligomers.

8. Coated panel according to claim 1, wherein the relief is provided in register with a printed decor of the decorative layer.

9. Coated panel according to claim 1, wherein the coated panel has a relief of gloss differences on its surface.

10. Coated panel according to claim 1, wherein the wear layer (5) is obtained on the basis of a mixture comprising at least on the one hand an acrylate resin or an unsaturated polyester resin, and on the other hand a thermal initiator and a photoinitiator, and wherein the acrylate resin or the unsaturated polyester resin is partially cured by UV radiation.

11. Coated panel according to claim 1, wherein the wear layer (5) is obtained on the basis of a mixture comprising at least on the one hand an acrylate resin or an unsaturated polyester resin, and on the other hand a thermal initiator and a photoinitiator, and wherein the acrylate resin or the unsaturated polyester resin is partially cured by UV radiation before the acrylate resin or the unsaturated polyester resin is thermally cured.

7. The coated panel of claim 1, wherein, ​ ​ ​ ​ ​ 12. The coated panel according to claim 1, wherein the wear layer (5) comprises a thermally cured acrylate resin, wherein the acrylate resin comprises between 20 and 60% by weight of monomers prior to curing.

13. The coated panel according to claim 1, wherein the acrylate resin or the unsaturated polyester resin comprises hard particles selected from alumina oxide particles, silica oxide or silicon carbide particles.

14. The coated panel according to claim 1, wherein the wear layer per square meter is obtained by 30 to 300 grams of the acrylate resin or the unsaturated polyester resin.

15. The coated panel according to claim 1, wherein the wear layer (5) comprises a thermally cured acrylate resin; and wherein the acrylate resin comprises a hydroxyl functional acrylate and / or a hydroxyl functional urethane acrylate.

16. The coated panel according to claim 1, wherein the wear layer (5) comprises a thermally cured acrylate resin; and wherein the acrylate resin comprises an isocyanate polymer and / or an isocyanate functional acrylate.

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