Acrylate coating composition and method for applying a coating layer

Abstract

An acrylate coating composition is disclosed for the application of a protective coating layer to a substrate. The acrylate coating composition comprises at least an acrylate oligomer. The acrylate coating composition comprises at least a component comprising at least one isocyanate group.

Description

[0001] Acrylate coating composition and method for applying a coating layer

[0002] The invention relates to acrylate coating compositions and to methods for applying a protective acrylate coating layer to a substrate, e.g. to provide a protective acrylate coating layer to a decorative panel.

[0003] Acrylate coating compositions and methods for applying a protective acrylate coating layer onto a substrate for the production of a decorative panel are disclosed in W02020 / 095196A1.

[0004] WO202 1 / 224843 Al relates to a partially cured coated sheet and discloses a sheet that comprises a support layer and a coating layer on a side of the support layer. The coating layer is partially cured. The coating layer comprises carbon-carbon double bonds, wherein the relative amount of carbon-carbon double bonds is higher at the surface of the coating layer than at the contact surface of the coating layer with the support layer. Methods are disclosed to manufacture such sheets; and to produce a decorative panel using such sheets.

[0005] It is an objective of the invention to provide improved acrylate coating composition and improved methods for applying a protective acrylate coating to a substrate.

[0006] The first aspect of the invention is an acrylate coating composition for the application of a protective coating layer to a substrate. The acrylate coating composition comprises at least an acrylate oligomer. The acrylate coating composition comprises at least a component comprising at least one isocyanate group.

[0007] It is a benefit of such coating composition that it can be partly cured using increasing temperature in which the isocyanate groups reacts with hydroxyl groups present in the acrylate coating composition or with hydroxyl groups present in the substrate onto which the acrylate coating composition is applied. The reaction of isocyanate groups with hydroxyl groups leads to the formation of a urethane bond. The formation of the urethane bonds can result in the formation of a tack free coating layer, that has a good shelf life and that can be cured in future processes by means of an addition reaction of the acrylate double bonds of the acrylate coating layer.

[0008] The curing by addition reaction of the acrylate double bonds of the acrylate coating layer can be performed by a thermal pressing operation, in which the acrylate coating layer is not only cured but is also provided with a texture by copying the texture of the press element. Preferably, in the thermal pressing operation, the acrylate coating layer copies the texture as well as the gloss from the textured pressing element.

[0009] The presence of components in the acrylate coating layer that provide the acrylate coating composition with two different curing mechanisms ensures that the final cured coating layer obtained from the acrylate coating composition has high scratch resistance.

[0010] A preferred acrylate coating composition is characterized in that the component comprising at least one isocyanate group is at least provided by the at least an acrylate oligomer being an acrylate oligomer, more preferably a polyurethane acrylate oligomer, comprising at least one isocyanate group.

[0011] Such embodiments provide acrylate coating compositions that when fully cured provide excellent properties, e.g. excellent scratch resistance. Furthermore, after increasing the temperature in which the isocyanate groups react and the acrylate groups do not react, good tack free coating layers are obtained with excellent shelf life. The acrylate groups can react later on via addition reactions in which the acrylate coating layer obtained from the acrylate coating composition is fully cured.

[0012] A preferred acrylate coating composition is characterized in that the component comprising at least one isocyanate group is at least provided by a component selected from the list of an acrylate oligomer (preferably a polyurethane acrylate oligomer) comprising at least one isocyanate group, a di-isocyanate, a polyisocyanate, an isocyanate bearing unsaturated acrylic ester resin; or combinations thereof. Such embodiments provide interesting ways of introducing isocyanate groups in the acrylic coating composition. The use of di-isocyanates or polyisocyanates result in coating compositions that have a lower cost.

[0013] The acrylate coating composition can comprise a polyisocyanate; preferably an aliphatic polyisocyanate and / or preferably a hexamethylene diisocyanate (HDI) or an isophorone (IPDI) based polyisocyanate, or combinations thereof.

[0014] The acrylate coating composition can comprise one or more than one polyisocyanate instead of or in combination with an isocyanate functional acrylate oligomer.

[0015] Preferred polyisocyanates have an isocyanate content of between 10 and 25 percent by weight.

[0016] Acrylate coating compositions comprising a di-isocyanate or a polyisocyanate preferably comprise a hydroxy functional acrylate reactive diluent.

[0017] When increasing the temperature of coating layers obtained from the acrylate coating composition, the isocyanate can react with the hydroxy functional acrylate reactive diluent forming urethane bonds, thereby bonding the acrylate reactive diluent in the acrylate coating layer, making the acrylate coating layer non-tacky and maintaining the acrylate functionality for later curing the acrylate coating layer via addition reactions of the acrylate double bonds.

[0018] Acrylate coating compositions comprising a di-isocyanate or a polyisocyanate preferably comprise a hydroxy functional acrylate oligomer, or a hydroxy functional unsaturated polyester. When increasing the temperature of coating layers obtained from the acrylate coating composition, the isocyanate can react with the hydroxyl groups of these components.

[0019] A preferred acrylate coating composition is characterized in that the acrylate coating composition comprises a hydroxy functional component. It is a benefit of such embodiments that the hydroxy functional component can react with the isocyanate groups of the acrylate coating composition, thereby forming urethane bonds that bind molecules in the acrylate coating layer and creating a tack-free coating layer that still comprise acrylate groups that can be reacted in future processes to a fully cured acrylate coating layer.

[0020] The hydroxy functional component can be selected from one or more of

[0021] - hydroxy functional acrylate resins,

[0022] - hydroxy functional acrylate oligomers, preferably having a molar mass of at least 800 g / mol;

[0023] - hydroxy functional polyester resins, preferably unsaturated hydroxy functional polyester resins;

[0024] - hydroxy functional polyether resins (e.g. a trifunctional polyester acrylate);

[0025] - hydroxy functional urethane acrylates, preferably hydroxy functional acrylate oligomers;

[0026] - aliphatic polyols;

[0027] - hydroxy functional unsaturated polyester acrylic resins;

[0028] - hydroxy functional unsaturated polyester resin;

[0029] - one or more hydroxy functional mono, di, tri, tetra or penta acrylate functional reactive diluents preferably having a molar mass lower than 1000 g / mol, and more preferably lower than 600 g / mol; or combinations thereof.

[0030] Preferably, the combined amount of thermo-initiators in the acrylate coating composition is less than 1 wt%. The amount of thermo-initiators can be kept so low, as the thermally induced addition reaction of the acrylate double bonds in the acrylate coating composition can be performed in a press element (e.g. in a single day light press), which means that oxygen inhibition is prevented. The second aspect of the invention relates to an acrylate coating composition characterized in that the acrylate coating composition comprises a hydroxy functional acrylate oligomer.

[0031] It is a benefit of acrylate coating compositions of the second aspect of the invention that they can be applied, and that after passing through an oven, a non-tacky coating layer is obtained. The non-tacky coating layer still has acrylate reactive groups that can be cured in a subsequent process, e.g. in a thermal pressing operation in which the coating layer obtained from the acrylate coating composition is embossed and at the same time cured in which thermally initiated addition reactions between the acrylate double bonds occur.

[0032] The acrylate coating composition of the second aspect of the invention can comprise a non-reactive solvent, beneficial for reducing the viscosity of the acrylate coating composition in order to facilitate its application. The non-reactive solvent can be volatized in an oven after the application of the acrylate coating composition of the second aspect of the invention.

[0033] The hydroxy functional acrylate oligomer can be a hydroxy functional acrylate acrylic oligomer.

[0034] In a preferred embodiment, the acrylate coating composition of the second aspect of the invention does not comprises isocyanate groups.

[0035] Optionally, the acrylate coating composition of the second aspect of the invention is an acrylate coating composition as in any embodiment of the preceding claims.

[0036] A preferred coating composition of the first aspect or of the second aspect of the invention is characterized in that the acrylate coating composition does not comprise acrylate reactive diluents, wherein acrylate reactive diluents are defined as diluents comprising at least one acrylate group and having a molar mass lower than 1000 g / mol, and preferably lower than 600 g / mol. However, possible exception can be made for the introduction of acrylate reactive diluents comprising at least one hydroxyl group, wherein acrylate reactive diluents are defined as diluents comprising at least one acrylate group and having a molar mass lower than 1000 g / mol, and preferably lower than 600 g / mol. Acrylate reactive diluents comprising at least one hydroxyl group will react when increasing the temperature with isocyanate groups, thereby forming urethane bonds and incorporating the acrylate reactive diluent in a molecular network, preventing it from diffusing. This way, a non- tacky coating layer can be obtained with acrylate coating compositions comprising acrylate reactive diluents comprising at least one hydroxyl group, while the acrylate functionality is maintained for later curing.

[0037] The acrylate coating composition of the first aspect or of the second aspect can comprise acrylate reactive diluents having a molar mass lower than 1000 g / mol (and preferably lower than 600 g / mol), preferably in an amount less than 50 wt% of the acrylate coating composition, more preferably in a n amount less than 40 wt% of the acrylate coating composition, more preferably in an amount less than 30 wt% of the acrylate coating composition. Preferred acrylate reactive diluents in the acrylate coating composition have hydroxyl functionality.

[0038] Acrylate reactive diluents in the acrylate coating composition have the benefit that they reduce the viscosity of the acrylate coating composition, facilitating the application of the acrylate coating composition. Contrary to the possible use of non-reactive solvents, the acrylate reactive diluents are not evaporated.

[0039] The acrylate coating composition of the first aspect or of the second aspect can comprise one or more mono, di, tri, tetra or penta acrylate functional reactive diluents preferably having a molar mass lower than 1000 g / mol, and more preferably lower than 600 g / mol; and / or one or more mono, di, tri, tetra or penta acrylate functional acrylic acid esters preferably having a molar mass lower than 1000 g / mol, and more preferably lower than 600 g / mol. Preferably such di, tri, tetra or penta acrylate functional reactive diluents and / or di, tri, tetra or penta acrylate functional acrylic acid esters have hydroxyl functionality.

[0040] A preferred acrylate coating composition of the first aspect or of the second aspect is characterized in that the acrylate coating composition comprises one more hydroxy functional mono, di, tri or tetra acrylate functional reactive diluents (preferably having a molar mass lower than 1000 g / mol, and more preferably lower than 600 g / mol), preferably selected from the list of 4-(ethenyloxy)-l -butanol (HBVE), pentaerythritol triacrylate (PETIA), dipentaerythritol pentaacrylate (DiPEPA), 2-hydroxypropyl methacrylate (HPMA), (hydroxyethyl)methacrylate (HEMA), 4-hydroxybutyl acrylate (4-HBA); or combinations thereof.

[0041] An acrylate coating composition of the first aspect or of the second aspect comprising non-reactive solvent preferably comprises less than 40 wt% reactive diluents, more preferably less than 30 wt% reactive diluents, even more preferably less than 25 wt% reactive diluents, and most preferred no reactive diluents at all.

[0042] A preferred acrylate coating composition of the first aspect or of the second aspect is characterized in that the acrylate coating composition comprises non-reactive solvent, more preferably wherein the amount of non-reactive solvent in the acrylate coating composition is between 5 and 60 wt%.

[0043] The introduction of the non-reactive solvent in the acrylate coating composition allows to have an acrylate coating composition with sufficiently low viscosity for easy application, without the use of or with limited use of reactive diluents. It is also possible to use longer chain length or more branched acrylate oligomers in the acrylate coating composition.

[0044] Preferred solvents are selected from an ester (e.g. butyl acetate, ethyl acetate, methoxypropyl acetate), a ketone (e.g. acetone, methyl ethyl ketone, methyl isobutyl ketone), an aromatic hydrocarbon (e.g. xylene); or mixtures thereof. It is not excluded however that the acrylate coating composition substantially does not comprise non-reactive solvent. Non-reactive solvents need to be evaporated from the acrylate coating layer applied from the acrylate coating composition, which requires thermal energy and a post processing of the vapors.

[0045] A preferred acrylate coating composition of the first aspect or of the second aspect is characterized in that the acrylate coating composition comprises a first thermo-initiator.

[0046] It is a benefit of such embodiments that the first thermo-initiator can initiate addition reactions of the acrylate double bonds present in the acrylate coating composition.

[0047] The first thermo-initiator can be selected to be activated at temperatures higher than the temperature of a processing step in which the temperature is increased of an acrylate coating layer obtained from the acrylate coating composition in order for the acrylate coating layer to be brought into non-tacky state by the reaction of isocyanate groups present in the acrylate coating composition. In a later process step - e.g. in a thermal pressing operation - the acrylate coating layer can be cured by activating the first thermoinitiator resulting in addition reactions of the acrylate double bonds of the acrylate coating composition.

[0048] Therefore, in a preferred embodiment, the first thermo-initiator has a ten hour half-life temperature higher than 75°C. Such embodiment allows that the first thermo-initiator is only activated in a thermal pressing operation.

[0049] The first thermo-initiator can be a peroxide type thermo-initiator.

[0050] A preferred acrylate coating composition of the first aspect or of the second aspect comprises a first thermo-initiator and a second thermo-initiator, wherein the 60 seconds half-life of the second thermo-initiator is at least 8°C higher than the 60 seconds half-life of the first thermo-initiator. A more preferred acrylate coating composition of the first aspect or of the second aspect comprises a third thermo-initiator, wherein the 60 seconds half-life of the third thermoinitiator is at least 8°C higher than the 60 seconds half-life of the second thermo-initiator.

[0051] An even more preferred acrylate coating of the first aspect or of the second aspect comprises a fourth thermo-initiator, wherein the 60 seconds half-life of the fourth thermo-initiator is at least 8°C higher than the 60 seconds half-life of the third thermoinitiator.

[0052] The presence of the second thermo-initiator, and if present of the third thermo-initiator and if present of the fourth thermo-initiator have the benefit that in a thermal pressing operation the thermo-initiators are activated at different temperatures, resulting in a gradual initiation of double bond acrylate addition reactions. As the curing of the acrylate coating composition is gradual, the ability of the acrylate coating composition to flow, is maintained, such that the acrylate coating layer obtained from the acrylate coating composition can be provided with an embossment by copying the texture of the press element used in the thermal pressing operation.

[0053] Preferred second thermo-initiators, preferred third thermo-initiators and preferred thermo-initiators are peroxide type thermo-initiators.

[0054] A preferred acrylate coating composition of the first aspect or of the second aspect is characterized in that the acrylate coating composition comprises one or more than one photo-initiator. Such embodiments are advantageous as they allow that a UV-radiation step can be performed to partially cure the acrylate coating composition, e.g. instead of or in addition to a thermal step to cure the acrylate coating composition to non-tacky states, or e.g. to perform a UV-radiation step to ensure that an acrylate coating layer is fully cured after a thermal pressing operation onto the acrylate coating layer.

[0055] Preferred photo initiators comprise or consist of Noirish type I photo initiators. Norrish type I photo initiators are preferred as they allow to achieve thick coating layers. More preferred photo initiators comprise or consist of multifunctional Norrish type I photo initiators.

[0056] Preferred photo initiators comprise phosphine oxide Norrish type I photo initiators, e.g. phenyl bis(2,4,6-trimethylbenzoyl)phosphine oxide (BAPO - CAS 162881-26-7).

[0057] Examples of photo initiators that can be used in the invention are difunctional alpha hydroxy ketone (CAS 71868-15-0), phenyl bis(2,4,6-trimethylbenzoyl)phosphine oxide (BAPO - CAS 162881-26-7) and 1, l'-(methylene-di -4,1 -phenylene)bis[2 -hydroxy -2- methyl-1 -propanone] (CAS 474510-57-1).

[0058] A preferred acrylate coating composition of the first aspect or of the second aspect is characterized in that the acrylate coating composition does not comprise a photo-initiator. Such embodiments are preferred as no equipment (e.g. UV-radiation equipment or electron beam radiation equipment) is required to activate the photo-initiator. Coating layers applied from such acrylate coating compositions can be cured only using thermal energy.

[0059] A preferred acrylate coating composition of the first aspect or of the second aspect is characterized in that the acrylate coating composition comprises additives selected from one or more than one of abrasion resistant particles (e.g. aluminum oxide particles, diamond particles, silicon carbide particles), wetting agents, or easy-to-clean particles.

[0060] Such acrylate coating compositions allow obtaining acrylate coating layers with specific properties and performance.

[0061] A preferred acrylate coating composition of the first aspect or of the second aspect is characterized in that the acrylate coating composition comprises at least an isocyanate functional acrylate oligomer, more preferably an isocyanate functional urethane acrylate oligomer, even more preferably an isocyanate functional aliphatic urethane acrylate oligomer. Such embodiments are preferred as they allow obtaining non-tacky acrylate coating layers after a thermal treatment of coating layers obtained from the acrylate coating composition, and after final curing of the acrylate coating composition in which the acrylate groups react a very strong and very scratch and abrasion resistant coating layer is obtained.

[0062] Preferred isocyanate functional acrylate oligomer has isocyanate functionality at least 2, and preferably at least 2.2, more preferably at least 2.4. Such embodiments further improve the performance of the acrylate coating composition and of acrylate coating layers obtained from such acrylate coating compositions.

[0063] The isocyanate content of preferred isocyanate functional acrylate oligomers for use in the invention is between 3 and 25 wt%. Such embodiments further improve the performance of the acrylate coating composition and of acrylate coating layers obtained from such acrylate coating compositions.

[0064] A preferred isocyanate functional acrylate oligomer has acrylate functionality at least 0.7, more preferably at least 1, more preferably at least 2, more preferably at least 2.2 Higher acrylate functionality of isocyanate functional acrylate oligomer results in more scratch resistant acrylate coating layers after they have been fully cured.

[0065] A preferred acrylate coating composition of the first aspect or of the second aspect is characterized in that the acrylate coating composition comprises a crosslinker. The crosslinkers can assist in the formation in a thermal process step of a tack-free coating layer, while acrylate groups are still sufficiently present in the tack-free coating layer allowing a future process step in which the acrylate coating layer is embossed and cured by means of a thermal pressing operation.

[0066] Preferred crosslinkers are selected from the list consisting of isocyanate, carbodiimide, aziridine; and combinations thereof. A preferred acrylate coating composition of the first aspect or of the second aspect is characterized in that the acrylate coating composition comprises a catalyst, e.g. a metallic component, preferably a tin component, e.g. dibutyltin dilaurate (DBTL), dioctyltin dilaurate, bismuth carboxylate, zinc carboxylate, chelates of zirconium or aluminum.

[0067] The catalyst will facilitate the reaction of the isocyanate groups in the acrylate coating composition when increasing the temperature of acrylate coating layers obtained from the acrylate coating composition.

[0068] A preferred acrylate coating composition of the first aspect or of the second aspect is characterized in that the acrylate coating composition comprises a catalyst, wherein the catalyst is a metal soap. The metal soap can be a sodium soap, a calcium soap, a bismuth soap or a zinc soap (e.g. zinc neodecanate), or combinations thereof.

[0069] Preferred metal soaps are unsaturated metal soaps, more preferably unsaturated sodium soaps, unsaturated calcium soaps, unsaturated bismuth soaps or unsaturated zinc soaps.

[0070] The use of metal soaps has shown to be particularly beneficial, as the metal soap not only catalyses urethane formation of the isocyanate groups present in the acrylate coating composition, but also prevents peroxide type thermo-initiators from initiating reaction at room temperature during longer term storage of tack free coating layers that will be processed later on to fully cured state.

[0071] The metal soaps also ensure that all isocyanate groups react in a process step in which the temperature is increased to cure the acrylate coating layer to non-tacky state. This way, no isocyanate groups are present in the non-tacky coating layer. Presence of isocyanate groups in the not-tacky coating layer could be harmful, e.g. in coated paper stored in roll form. Isocyanate groups in the stored coated paper roll could react, creating a memory in the paper. When unrolling the paper from the roll, the sheet of paper would keep a bent shape, which is undesirable. A preferred acrylate coating composition of the first aspect or of the second aspect is characterized in that the acrylate coating composition comprises at least 35 wt% of acrylate oligomer, wherein the acrylate oligomer has molecular mass at least 800 g / mol; and preferably at least 1000 g / mol.

[0072] A preferred acrylate coating composition of the first aspect or of the second aspect is characterized in that the acrylate coating composition comprises a urethane acrylate oligomer having isocyanate functionality and molar mass at least 800 g / mol (and preferably at least 1000 g / mol), and one or more of

[0073] - an oligomer - preferably an acrylate oligomer, more preferably a urethane acrylate oligomer -, preferably having molar at least 800 g / mol (and preferably at least 1000 g / mol), having hydroxyl functionality, or,

[0074] - a reactive diluent, preferably an acrylate reactive diluent, having hydroxyl functionality, preferably wherein the reactive diluent has molar mass less than 600 g / mol, or

[0075] - a polyester acrylate having hydroxyl functionality.

[0076] Such acrylate coating compositions have the benefit that the isocyanate groups can react with the hydroxyl groups to form a non-tacky coating layer.

[0077] A preferred acrylate coating composition of the first aspect or of the second aspect is characterized in that the acrylate coating composition comprises a urethane acrylate oligomer - preferably having molar mass higher than 800 g / mol (and more preferably higher than 1000 g / mol) - having hydroxyl functionality, and an oligomer - preferably a urethane acrylate oligomer - having isocyanate functionality.

[0078] Such acrylate coating compositions have the benefit that the isocyanate groups can react with the hydroxyl groups to form a non-tacky coating layer.

[0079] A preferred acrylate coating composition of the first aspect or of the second aspect comprises a phosphonate adhesion promotor. This embodiment provides improved adhesion of the acrylate coating composition to the substrate onto which it is applied. A preferred acrylate coating composition of the first aspect or of the second aspect of the invention is characterized in that the acrylate coating composition comprises a matting agent.

[0080] Such embodiments are preferred, as the production of a coating layer with a matte surface is facilitated. The structured press element used to emboss and cure the coating layer can be textured to provide a macro structure (e.g. embossments) to the coating layer as well as to provide a matte surface (or to provide different gloss levels) to the coating layer, the latter via copying the micro texture of the structured press element. However, when the required micro structure is too fine or too rough, it has been observed that the coating layer can stick to the structured press element, resulting in quality problems such as press element contamination. Adding a matting agent in the acrylate coating composition results in a coating layer that has a more matte surface without having the need to provide the structured press element with a very fine surface texture.

[0081] The matting agent preferably provides between 2 and 14 wt%, and more preferably between 3 and 10 wt%, of the acrylate coating composition.

[0082] A preferred matting agent for use in the invention is amorphous silica, preferably having S50 particle size between 3 and 20 micrometer. The S50 particle size is the particle size in the particle size distribution according to volume as determined using laser diffraction at which 50% of the particles are smaller than the S50. Amorphous silica has shown good compatibility with the acrylate coating composition.

[0083] The third aspect of the invention is a method for applying an acrylate coating to a substrate. The method comprises the steps of

[0084] - providing a substrate;

[0085] - providing an acrylate coating composition as in any embodiment of the first aspect and / or of the second aspect of the invention;

[0086] - applying the acrylate coating composition to the substrate thereby obtaining an acrylate coating layer on the substrate;

[0087] - processing the acrylate coating layer to non-tacky state; wherein the step of processing the acrylate coating layer to non-tacky state comprises the step of increasing the temperature of the acrylate coating layer; and / or the step of irradiating the acrylate coating layer with UV-radiation.

[0088] The step of increasing the temperature of the acrylate coating layer will bring the acrylate coating layer to non-tacky state.

[0089] In embodiments of the invention, the step of increasing the temperature of the acrylate coating layer can provide a reaction between isocyanate groups of the acrylate coating layer and hydroxyl groups of the acrylate coating layer or of the substrate. This way, the acrylate coating layer is made non-tacky in a convenient way, keeping the acrylate double bonds available for later curing to a fully cured state.

[0090] In embodiments comprising the step of irradiating the acrylate coating layer with UV- radiation, the UV radiation step can process the acrylate coating layer to non-tacky state.

[0091] Preferably, in the step of increasing the temperature of the acrylate coating layer, the temperature of the acrylate coating layer is increased to a temperature of at least 60 °C (and more preferably at least 70 °C), and preferably to a temperature less than 140 °C (and more preferably to a temperature less than 130 °C).

[0092] Preferably, the step of increasing the temperature of the acrylate coating layer is performed at least by means of a hot air oven, or by means of infrared radiation, or by means of microwave radiation, or by means of combinations thereof, thereby partially curing the acrylate coating layer to non-tacky state.

[0093] Preferably, in the step of increasing the temperature of the acrylate coating layer, isocyanate groups of the at least a component comprising at least one isocyanate group react with hydroxyl groups present in the acrylate coating composition and / or in the substrate.

[0094] This way, a network of the molecules of the acrylate coating layer is created making the acrylate coating layer tack free. A preferred method is characterized in that the non-tacky state of the acrylate coating layer is a state which allows that the acrylate coating layer is embossed and cured in a thermal pressing operation.

[0095] The substrate with the non-tacky acrylate coating layer can be stored and processed later in a thermal pressing operation.

[0096] A preferred method is characterized in that the method does not comprise irradiation of the acrylate coating layer with UV-radiation nor with electron beam radiation for processing the acrylate coating layer to non-tacky state.

[0097] Such embodiments have the benefit that no special equipment is needed to bring the acrylate coating layer to non-tacky state.

[0098] A preferred method is characterized in that the step of processing the acrylate coating layer to non-tacky state comprises the step of irradiating the acrylate coating layer with UV-light (e.g. using UV-lamps, using UV-LED, using excimer radiation, or combinations thereof) and / or electron beam radiation.

[0099] This embodiment has the benefit that the radiation energy will create an addition reaction of part of the acrylate double bonds present in the acrylate coating composition, improving the non-tacky state of the acrylate coating layer.

[0100] The optional step of irradiating the acrylate coating layer is preferably performed after a step of the step of increasing the temperature of the acrylate coating layer. This way, a better non-tacky state of the acrylate coating layer can be realized.

[0101] A preferred method is characterized in that the acrylic coating composition comprises a non-reactive solvent and that the non-reactive solvent is evaporated in the step of increasing the temperature of the acrylate coating layer. The evaporation of the non-reactive solvent will increase the viscosity of the liquid acrylate coating layer and will facilitate a reaction between isocyanate groups in the acrylate coating layer with hydroxyl groups, in which urethane bonds are formed for creating the non-tacky state of the acrylate coating layer.

[0102] A preferred acrylate coating layer has a dry weight between 30 (and preferably at least 100, more preferably at least 150) and 300 gram per square meter. Such embodiments allow that in a thermal pressing operation an embossed structure is obtained in the acrylate coating layer and the acrylate coating layer with its embossed structure is cured. This way, an acrylate coating layer can be obtained that imitates the texture of a natural material (e.g. wood) and which has excellent wear resistance.

[0103] A preferred method is characterized in that the method comprises the step of at least partially - and preferably to substantially fully cured state - curing the non-tacky acrylate coating layer by means of a thermal pressing operation.

[0104] The thermal pressing operation allows to press a texture in the acrylate coating layer and cure the acrylate coating layer, thereby obtaining a textured acrylate coating layer having excellent wear resistance.

[0105] Preferably, the substrate (e.g. an impregnated sheet of paper) carrying the acrylate coating layer has moisture content less than 8 wt% (and preferably less than 7 wt%, more preferably less than 6 wt%) when it is presented to the thermal pressing operation, and / or it is dried to such moisture content before presenting it to the thermal pressing operation. The moisture content is tested by submitting the sample to a temperature of 160 °C during 5 minutes and cooling the sample afterwards in an dessicator.

[0106] The acrylate coating composition preferably comprises at least one thermo-initiator; wherein in the thermal pressing operation the thermo-initiator initiates an addition reaction of acrylate double bonds. Preferably, the at least one thermo-initiator is selected such that it is not activated in a thermal treatment step of the acrylate coating layer after applying it to a substrate in order to partially cure it, preferably to non-tacky state. This way, the at least one thermoinitiator can be activated in a thermal pressing step in which the acrylate coating layer is cured and in which the acrylate coating layer can be provided with a texture.

[0107] Preferably, the at least one thermo-initiator has activation temperature higher than 140 °C.

[0108] This way, the acrylate double bonds react to cure the acrylate coating layer.

[0109] The acrylate coating layer can be provide with a texture in the thermal pressing operation, preferably a texture in register with a printed decor of the substrate.

[0110] When using a paper having a printed wood decor as substrate and embossing the acrylate coating layer in register with the printed wood decor, a very realistic imitation of real wood can be obtained.

[0111] A preferred method is characterized in that the acrylate coating layer is subjected to a radiation curing step - preferably by means of UV-radiation or by means of electron beam radiation - performed after the step of at least partially curing the acrylate coating layer by means of thermal pressing operation.

[0112] The radiation curing step can be performed to ensure that the acrylate coating layer is fully cured, in order to obtain its optimal performance.

[0113] A preferred method is characterized in that the acrylate coating layer is not subjected to a radiation curing step after the step of at least partially curing the acrylate coating layer by means of thermal pressing operation.

[0114] This embodiment involves that the production line can be kept more simple, as no equipment is required for performing a radiation curing step. A preferred method is characterized in that the substrate is laminated to a board in the thermal pressing operation.

[0115] To this end, the substrate can be provided at the side opposite to the side comprising the acrylate coating layer with an adhesive - e.g. a partially cured thermoset resin - for laminating the substrate to the board.

[0116] The board can be selected from a wood-based board (e.g. a wood fiber board, a wood particle board, or a plywood board), a mineral board (e.g. a cement based board, a magnesium oxide based board or a gypsum based board), a whether or not filled thermoplastic board (e.g. a whether or not filled polyvinyl chloride based board) or a stack of resin impregnated kraft sheet of paper.

[0117] A preferred method is characterized in that the method comprises the steps of

[0118] - providing a second acrylate coating composition;

[0119] - applying the second acrylate coating composition to the substrate;

[0120] - partially curing the second acrylate coating composition applied to the substrate by means of UV-radiation (e.g. by means of UV-lamps, by means of UV-LED or by means of excimer radiation - but preferably without excimer radiation) or electron beam radiation;

[0121] - wherein the steps of applying the second acrylate coating composition to the substrate and partially curing the second acrylate coating composition are performed before the step of applying the acrylate coating composition to the substrate;

[0122] - wherein the second acrylate coating composition comprises one or more acrylate oligomers (preferably wherein said oligomers have a molar mass equal to or higher than 800 g / mol, and preferably higher than 1000 g / mol, and preferably lower than 10000 g / mol) and one or more acrylate reactive diluents having a molar mass lower than 1000 g / mol, preferably lower than 800 g / mol.

[0123] It is benefit of such embodiments that a thin layer of the acrylate coating composition can be applied on a thicker layer of the second acrylate coating composition. The second acrylate coating composition comprises at least a component comprising at least one isocyanate group and is therefore more expensive than the second acrylate coating - composition. The acrylate coating composition on top of the second acrylate coating composition makes it more easy to obtain a tack-free acrylate coating layer, such that the substrate wit the non tacky acrylate coating layer has a long shelf life.

[0124] It is not required to cure in the step of partially curing the second acrylate coating composition applied to the substrate by means of UV-radiation or electron beam radiation to non-tacky state. Curing the layer provided by the acrylate coating composition to non- tacky state will ensure that the coated substrate is in non-tacky state.

[0125] Because of its curing by means of reaction of isocyanate groups on the one hand and the addition reaction of the acrylate double bonds on the other hand, after final curing an acrylate coating layer with excellent wear resistance - including excellent scratch resistance - is obtained.

[0126] The use of the cheaper second acrylate coating composition in combination with the more expensive acrylate coating composition reduces the total cost of the coating applied to the substrate, while obtaining excellent processability and performance.

[0127] Preferably, the amount of dry weight per square meter applied of the second acrylate coating composition is higher than - and preferably at least double - the amount of dry weight per square meter applied of the acrylate coating composition.

[0128] In a preferred embodiment in which the second acrylate coating composition is applied before applying the acrylate coating composition, the second acrylate coating composition does not comprise abrasion resistance increasing particles whereas the acrylate coating composition does comprise abrasion resistance increasing particles.

[0129] Such embodiments provide even better scratch resistance to the coated substrate. In a preferred embodiment in which the second acrylate coating composition is applied before applying the acrylate coating composition, the second acrylate coating composition and the acrylate coating composition both comprise abrasion resistance increasing particles, wherein the average particle size by number of the abrasion resistance increasing particles of the acrylate coating composition is smaller than the average particle size by number of the abrasion resistance increasing particles of the second acrylate coating composition.

[0130] This way, the substrate is provided with a coating layer with high wear resistance and with high scratch resistance. The presence of the finer abrasion resistance increasing particles in the acrylate coating composition results in an improved scratch resistance, as these finer particles are present at the surface of the coated substrate.

[0131] A preferred method is characterized in that after applying the acrylate coating composition and processing the acrylate coating layer to non-tacky state; a second acrylate coating composition is applied, thereby providing the substrate with a second acrylate coating layer. The second acrylate coating composition comprises one or more acrylate oligomers (preferably wherein said oligomers have a molar mass equal to or higher than 800 g / mol and preferably higher than 1000 g / mol and lower than 10000 g / mol) and one or more acrylate reactive diluents having a molar mass lower than 1000 g / mol (and preferably lower than 800 g / mol.

[0132] It is a benefit of this embodiment that a coated substrate is obtained with better adhesion of the coating compared to the option whereby the second acrylate coating composition is applied first to the substrate, followed by application of the acrylate coating composition.

[0133] Preferably, after its application the second acrylate coating composition is partially cured by means of UV-radiation (e.g. by means of UV-lamps, by means of UV-LED or by means of excimer radiation - but preferably without excimer radiation) or electron beam radiation to non-tacky state. In embodiments wherein the second acrylate coating composition is applied to the substrate after applying the acrylate coating composition, preferably the dry weight applied per square meter of the second acrylate coating composition is less than the dry weight applied per square meter of the acrylate coating composition. More preferably, the dry weight applied of the second acrylate coating composition is less than 30% of the dry weight applied of the acrylate coating composition.

[0134] Such embodiments ensure that excellent performance is obtained at a lower cost.

[0135] In a preferred embodiment in which the acrylate coating composition is applied before applying the second acrylate coating composition, the acrylate coating composition does not comprise abrasion resistance increasing particles whereas the second acrylate coating composition does comprise abrasion resistance increasing particles.

[0136] This embodiment is beneficial, as it ensures that a coated substrate can be obtained having excellent scratch resistance.

[0137] In a preferred embodiment in which the acrylate coating composition is applied before applying the second acrylate coating composition, the acrylate coating composition and the second acrylate coating composition both comprise abrasion resistance increasing particles, wherein the average particle size by number of the abrasion resistance increasing particles of the second acrylate coating composition is smaller than the average particle size by number of the abrasion resistance increasing particles of the acrylate coating composition.

[0138] This way, the substrate is provided with a coating layer with high wear resistance and with high scratch resistance. The finer abrasion resistance increasing particles in the second acrylate coating composition results in an improved scratch resistance, as these finer particles are present at the surface of the coated substrate. Preferred second acrylate coating compositions for use in the invention comprise a photo-initiator. The photo-initiator enables the partial curing of the acrylate coating composition after its application.

[0139] Preferred photo initiators for use in the second acrylate coating composition comprise or consist of Norrish type I photo initiators. Norrish type I photo initiators are preferred as they allow to achieve thick coating layers.

[0140] More preferred photo initiators for use in the second acrylate coating composition comprise or consist of multifunctional Norrish type I photo initiators.

[0141] Preferred photo initiators for use in the second acrylate coating composition comprise phosphine oxide Norrish type I photo initiators, e.g. phenyl bis(2,4,6- trimethylbenzoyl)phosphine oxide (BAPO - CAS 162881-26-7).

[0142] Examples of photo initiators for use in the second acrylate coating composition are difunctional alpha hydroxy ketone (CAS 71868-15-0), phenyl bis(2,4,6- trimethylbenzoyl)phosphine oxide (BAPO - CAS 162881-26-7) and l,l'-(methylene-di- 4, l-phenylene)bis[2-hydroxy-2-methyl-l -propanone] (CAS 474510-57-1).

[0143] Preferred second acrylate coating compositions for use in the invention do not comprise non-reactive solvents. The viscosity levels for ease of application of the second acrylate coating composition can be obtained by the reactive diluents in the second coating composition.

[0144] The acrylate oligomers of the second acrylate coating composition can be selected from polyester acrylates (preferably having acrylate functionality of at least 3), urethane acrylates, epoxy acrylates, unsaturated polyester acrylates, unsaturated polyester; and combinations thereof.

[0145] The second acrylate coating composition can comprise unsaturated polyester which are not unsaturated polyester acrylates. The average acrylate functionality of the acrylate reactive diluents of the second acrylate coating composition is preferably at least 2, preferably at least 2.5, more preferably at least 2.8.

[0146] In embodiments wherein the acrylate coating composition and a second acrylate coating composition are applied to the substrate, both are partially cured. In a subsequent thermal pressing operation, flow will occur in the layers provided by the acrylate coating composition and the second acrylate coating composition, enabling deep embossing of the coated substrate and curing of the embossed coating.

[0147] The second acrylate coating composition preferably comprises a first thermo-initiator.

[0148] The incorporation of the first thermo-initiator in the second acrylate coating composition has the same benefits as mentioned for the incorporation of the first thermo-initiator in the acrylate coating composition.

[0149] The second acrylate coating composition preferably comprises a first thermo-initiator and a second thermo-initiator, wherein the 60 seconds half-life of the second thermoinitiator is at least 8°C higher than the 60 seconds half-life of the first thermo-initiator.

[0150] The second acrylate coating composition preferably comprises a third thermo-initiator, wherein the 60 seconds half-life of the third thermo-initiator is at least 8°C higher than the 60 seconds half-life of the second thermo-initiator.

[0151] The second acrylate coating composition preferably comprises a fourth thermo-initiator, wherein the 60 seconds half-life of the fourth thermo-initiator is at least 8°C higher than the 60 seconds half-life of the third thermo-initiator.

[0152] The incorporation of the optional second thermo-initiator, the optional third thermoinitiator and the optional fourth thermo-initiator in the second acrylate coating composition has the same benefits as mentioned for the incorporation of the first thermoinitiator in the acrylate coating composition.

[0153] Preferably, the combined amount of thermo-initiators in the second acrylate coating composition is less than 1 wt%. The amount of thermo-initiators can be kept so low, as the thermally induced addition reaction of the acrylate double bonds in the second acrylate coating composition can be performed in a press element (e.g. in a single day light press), which means that oxygen inhibition is prevented.

[0154] A preferred second coating composition does not comprise acrylate oligomers having isocyanate groups nor acrylate oligomers having hydroxyl groups. Such embodiments have the benefit that the cost of the second coating composition is kept low, while sufficient performance and processing ease is obtained.

[0155] A preferred second coating composition does not comprise reactive diluents having isocyanate groups nor reactive diluents having hydroxyl groups. Such embodiments have the benefit that the cost of the second coating composition is kept low, while sufficient performance and processing ease is obtained.

[0156] A preferred method is characterized in that the substrate is selected from the list consisting of an impregnated sheet of paper (and preferably an impregnated printed sheet of paper), a polymer film (and preferably a printed polymer film or a transparent polymer film - e.g. a PVC-film), a wood based board, a wood fiber board, a wood chip board, an engineered wood board, a plywood board, a veneer layer, a magnesium oxide based board, a cement based board, a gypsum board, and a stack of resin impregnated kraft sheet of paper.

[0157] A preferred method is characterized in that the substrate comprises or consists of an impregnated sheet of paper, wherein the impregnated sheet of paper is impregnated with one or more of an aminoplast resin (e.g. a urea formaldehyde resin or a melamine formaldehyde resin or a melamine urea formaldehyde resin), an acrylate resin (preferably applied as an acrylate dispersion), a polyurethane resin (preferably applied as a polyurethane dispersion, more preferably as a UV-curable polyurethane dispersion), a reactive acrylate resin; or combinations thereof.

[0158] The impregnated sheet of paper can be an impregnated printed sheet of paper.

[0159] The impregnated sheet of paper can be an impregnated - preferably unprinted - sheet of paper, wherein the sheet of paper is an alfa cellulose fiber sheet of paper having an unimpregnated weight between 15 and 50 gram per square meter.

[0160] The impregnated sheet of paper can be an impregnated - preferably printed - sheet of paper, having unimpregnated weight between 50 and 120 gram per square meter.

[0161] The impregnated sheet of paper preferably comprises 35 - 135 wt% of dry resin calculated on the unimpregnated weight of the sheet of paper.

[0162] The moisture content of the impregnated sheet of paper is preferably less than 8 wt%, more preferably less than 7 wt%, even more preferably less than 6 wt%.

[0163] The impregnated sheet of paper can comprise an adhesion layer on the side onto which the acrylate coating layer will be applied. This way, adhesion between the impregnated sheet of paper and the coating layer applied can be improved.

[0164] The adhesion layer on the side onto which the acrylate coating layer will be applied can be selected from an acrylate layer (preferably applied as an acrylate dispersion), a melamine acrylate layer, a polyurethane layer, a polyurethane layer with acrylate functionality; or combinations thereof.

[0165] The adhesion layer on the side onto which the acrylate coating layer will be applied preferably has a dry weight between 4 and 30 gram per square meter.

[0166] The impregnated sheet of paper can comprise an adhesion layer on the side opposite to the side onto which the acrylate coating layer will be applied. This way, lamination of the impregnated sheet of paper provided with the non-tacky acrylate coating layer onto a board can be more easily performed in a thermal pressing operation wherein the acrylate coating layer is provided with a texture and wherein the acrylate coating layer is cured.

[0167] In the thermal pressing operation the acrylate coating layer can copy the texture as well as the gloss of the textured pressing element

[0168] The adhesion layer on the side opposite to the side onto which the acrylate coating layer will be applied can be selected from an aminoplast resin (e.g. a urea formaldehyde resin or a melamine urea formaldehyde resin), an acrylate layer (preferably applied as an acrylate dispersion), a melamine acrylate layer, a polyurethane layer, a polyurethane layer with acrylate functionality; or combinations thereof.

[0169] The adhesion layer on the side opposite to the side onto which the acrylate coating layer will be applied preferably has a dry weight between 4 and 30 gram per square meter.

[0170] Using the methods of the invention, decorative panels can be made, e.g. floor panels or furniture panels.

[0171] The fourth aspect of the invention relates to a coated substrate. The substrate is provided with an acrylate coating layer applied using an acrylate coating composition as in any embodiment of the first aspect of the invention. The acrylate coating layer comprises urethane bonds. The acrylate coating layer is not tacky and the acrylate coating layer comprises acrylate double bonds.

[0172] The coated substrate of the fourth aspect of the invention can be produced via embodiments of the third aspect of the invention. This substrate can be used in a thermal pressing operation in which the acrylate coating layer is provided with an embossed structure by copying the texture of the structure of the press element and in which the acrylate coating layer is cured by thermally induced addition reaction of the acrylate double bonds. The substrate can be selected from the list consisting of an impregnated sheet of paper (and preferably an impregnated printed sheet of paper), a polymer film (and preferably a printed polymer film or a transparent polymer film - e.g. a PVC-film), a wood based board, a wood fiber board, a wood chip board, an engineered wood board, a plywood board, a veneer layer, a magnesium oxide based board, a cement based board, a gypsum board, or a stack of resin impregnated kraft sheet of paper.

[0173] A preferred embodiment of the fourth aspect of the invention is characterized in that the substrate comprises or consists of an impregnated sheet of paper (and preferably an impregnated printed sheet of paper), wherein the impregnated sheet of paper is impregnated with one or more of an aminoplast resin (e.g. a urea formaldehyde resin or a melamine formaldehyde resin or a melamine urea formaldehyde resin), an acrylate resin (preferably applied as an acrylate dispersion), a polyurethane resin (preferably applied as a polyurethane dispersion, more preferably as a UV-curable polyurethane dispersion), a reactive acrylate resin; or combinations thereof.

[0174] A preferred embodiment of the fourth aspect of the invention is characterized in that the acrylate coating layer comprises a first thermo-initiator.

[0175] A preferred embodiment of the fourth aspect of the invention is characterized in that the acrylate coating layer comprises a first thermo-initiator and a second thermo-initiator, wherein the 60 seconds half-life of the second thermo-initiator is at least 8°C higher than the 60 seconds half-life of the first thermo-initiator.

[0176] A preferred embodiment of the fourth aspect of the invention is characterized in that the acrylate coating layer comprises a third thermo-initiator, wherein the 60 seconds halflife of the third thermo-initiator is at least 8°C higher than the 60 seconds half-life of the second thermo-initiator.

[0177] A preferred embodiment of the fourth aspect of the invention is characterized in that the acrylate coating layer comprises a fourth thermo-initiator, wherein the 60 seconds half- life of the fourth thermo-initiator is at least 8°C higher than the 60 seconds half-life of the third thermo-initiator.

[0178] The thermo-initiator(s) allow(s) that the acrylate coating layer can be thermally cured. When more than one thermo-initiator is used, the acrylate coating layer can be more gradually cured during a thermal pressing operation in which the acrylate coating layer is provided with embossments by copying the texture of the press element being used. Gradual curing is beneficial, as it allows more flow in the acrylate coating layer for deeper embossments.

[0179] A preferred embodiment of the fourth aspect of the invention is characterized in that the acrylate coating layer is configured such that in a thermal pressing operation the acrylate coating layer can be embossed by copying the texture of a texture press element and thermally cured.

[0180] As used in this document, the molar mass of a compound or composition is the calculated molar mass. The calculated molar mass is obtained by adding the atomic masses of all atoms present in the structural formula of a compound or composition. When the exact structural formula of a compound or composition is not known, the molar mass of the compound is the number average molecular weight determined using Triple Detection Size Exclusion Chromatography using tetra hydrofuran THF as eluent.

[0181] With the intention of better showing the characteristics of the invention, hereafter, as an example without any limitative character, several preferred embodiments are described, with reference to the accompanying drawings, wherein: figure 1 shows a method according to aspects of the invention for manufacturing a decorative panel; and figure 2 shows a decorative panel obtained with a method according to the invention.

[0182] The following acrylate coating compositions provide examples of the invention. Acrylate coating composition 1 A:

[0183] 90 parts by weight of a hydroxy functional acrylate acrylic oligomer dissolved in butyl acetate (50 wt% solids),

[0184] 10 parts by weight of isocyanate (e.g. Voramer 44),

[0185] 0.4 parts by weight of thermo-initiator TBEC, OO-(t-butyl) 0-(2-ethylhexyl) monoperoxycarbonate,

[0186] 0.4 parts by weight of thermo-initiator TAEC, OO-(t-amyl) 0-(2-ethylhexyl) monoperoxycarbonate,

[0187] 0.5 parts by weight of a bismuth based catalyst,

[0188] 5 parts by weight of aluminum oxide particles having average particle size between 15 and 20 micrometer,

[0189] Optionally, 2 parts by weight of a silicone acrylate leveling agent,

[0190] Optionally, 1 part by weight of Omnirad MBF photo-initiator,

[0191] Optionally, additional butyl acetate is added to adjust the viscosity for ease of application of the acrylate coating composition.

[0192] Acrylate coating composition IB:

[0193] 75 parts by weight of a hydroxy functional acrylate acrylic oligomer dissolved in butyl acetate (50 wt% solids),

[0194] 15 parts by weight of a trifunctional methacrylate monomer, e.g. TMPTMA (trimethylolpropane triacrylate),

[0195] 10 parts by weight of isocyanate (e.g. Voramer 44),

[0196] 0.4 parts by weight of thermo-initiator TBEC, OO-(t-butyl) 0-(2-ethylhexyl) monoperoxycarbonate,

[0197] 0.4 parts by weight of thermo-initiator TAEC, OO-(t-amyl) 0-(2-ethylhexyl) monoperoxycarbonate,

[0198] 0.5 parts by weight of a bismuth based catalyst,

[0199] 5 parts by weight of aluminum oxide particles having average particle size between 15 and 20 micrometer,

[0200] Optionally, 2 parts by weight of a silicone acrylate leveling agent,

[0201] Optionally, 1 part by weight of Omnirad MBF photo-initiator, Optionally, additional butyl acetate is added to adjust the viscosity for ease of application of the acrylate coating composition.

[0202] Acrylate coating composition 1C:

[0203] 100 parts by weight of a hydroxy functional acrylate acrylic oligomer dissolved in butyl acetate (50 wt% solids),

[0204] 0.4 parts by weight of thermo-initiator TBEC, OO-(t-butyl) 0-(2-ethylhexyl) monoperoxycarbonate,

[0205] 0.4 parts by weight of thermo-initiator TAEC, OO-(t-amyl) 0-(2-ethylhexyl) monoperoxycarbonate,

[0206] 0.5 parts by weight of a bismuth based catalyst,

[0207] 5 parts by weight of aluminum oxide particles having average particle size between 15 and 20 micrometer,

[0208] Optionally, 2 parts by weight of a silicone acrylate leveling agent,

[0209] Optionally, 1 part by weight of Omnirad MBF photo-initiator,

[0210] Optionally, additional butyl acetate is added to adjust the viscosity for ease of application of the acrylate coating composition.

[0211] Acrylate coating composition 2:

[0212] 50 parts by weight of isocyanate bearing aliphatic urethane acrylate oligomer (100% solids),

[0213] 20 parts by weight of hydroxyl polyester acrylate oligomer,

[0214] 20 parts by weight of a hydroxy functional reactive diluent, such as 4-hydroybutyl acrylate (4-HBA),

[0215] 10 parts by weight of isocyanate (e.g. Voramer 44),

[0216] 0.8 parts by weight of thermo-initiator TBEC, OO-(t-butyl) 0-(2-ethylhexyl) monoperoxycarbonate,

[0217] 0.5 parts by weight of a bismuth based catalyst,

[0218] 5 parts by weight of aluminum oxide particles having average particle size between 15 and 20 micrometer,

[0219] Optionally, 2 parts by weight of a silicone acrylate leveling agent,

[0220] Optionally, 1 part by weight of Omnirad MBF photo-initiator, Optionally, butyl acetate is added to adjust the viscosity for ease of application of the acrylate coating composition.

[0221] Acrylate coating composition 3 :

[0222] 50 parts by weight of isocyanate bearing aliphatic urethane acrylate oligomer diluted in butyl acetate (50% solids),

[0223] 50 parts by weight of a hydroxy functional acrylic acrylate oligomer diluted in butyl acetate (50% solids),

[0224] 0.8 parts by weight of thermo-initiator TBEC, OO-(t-butyl) 0-(2-ethylhexyl) monoperoxycarbonate,

[0225] 0.5 parts by weight of a bismuth based catalyst,

[0226] 5 parts by weight of aluminum oxide particles having average particle size between 15 and 20 micrometer,

[0227] Optionally, 2 parts by weight of a silicone acrylate leveling agent,

[0228] Optionally, 1 part by weight of Omnirad MBF photo-initiator,

[0229] Optionally, extra butyl acetate is added to adjust the viscosity for ease of application of the acrylate coating composition.

[0230] Acrylate coating composition 4:

[0231] 60 parts by weight of isocyanate bearing aliphatic urethane acrylate (100% solids),

[0232] 20 parts by weight of a hydroxy functional reactive diluent, e.g. (hydroxy ethyl)methacrylate (HEMA),

[0233] 20 parts by weight of hydroxy functional reactive diluent 4-hydroxybutyl acrylate

[0234] (4-HBA),

[0235] 0.6 parts by weight of thermo-initiator TBEC, OO-(t-butyl) 0-(2-ethylhexyl) monoperoxycarbonate,

[0236] 0.05 parts by weight of thermo-initiator TBPND, 2 tert, butylperoxyneodecanoate,

[0237] 0.5 parts by weight of a bismuth based catalyst,

[0238] 5 parts by weight of diamond particles having average particle size between 15 and 20 micrometer, 1 part by weight of Omnirad MBF photo-initiator,

[0239] Optionally, 2 parts by weight of a silicone acrylate leveling agent,

[0240] Optionally, additional butyl acetate is added to adjust the viscosity for ease of application of the acrylate coating composition.

[0241] Acrylate coating composition 5 :

[0242] 20 parts by weight of isocyanate bearing aliphatic urethane acrylate oligomer diluted in butyl acetate (50% solids),

[0243] 80 parts by weight of a hydroxy functional acrylate acrylic dissolved in butyl acetate (50 wt% solids),

[0244] 0.8 parts by weight of thermo-initiator TBEC, OO-(t-butyl) 0-(2-ethylhexyl) monoperoxycarbonate,

[0245] 0.5 parts by weight of a bismuth based catalyst,

[0246] 5 parts by weight of aluminum oxide particles having average particle size between 15 and 20 micrometer,

[0247] Optionally, 2 parts by weight of a silicone acrylate leveling agent,

[0248] Optionally, 1 part by weight of Omnirad MBF photo-initiator,

[0249] Optionally, additional butyl acetate is added to adjust the viscosity for ease of application of the acrylate coating composition.

[0250] Acrylate coating composition 6:

[0251] 50 parts by weight of an isocyanate bearing unsaturated acrylic ester,

[0252] 40 parts by weight of a hydroxy functional acrylic acrylate diluted in butyl acetate (50% solids),

[0253] 10 parts by weight of a hydroxy functional reactive diluent, e.g. (hydroxy ethyl)methacrylate (HEMA),

[0254] 0.8 parts by weight of thermo-initiator TBEC, OO-(t-butyl) 0-(2-ethylhexyl) monoperoxycarbonate,

[0255] 0.5 parts by weight of a bismuth based catalyst,

[0256] 5 parts by weight of aluminum oxide particles having average particle size between 15 and 20 micrometer,

[0257] Optionally, 2 parts by weight of a silicone acrylate leveling agent, Optionally, 1 part by weight of Omnirad MBF photo-initiator,

[0258] Optionally, additional butyl acetate is added to adjust the viscosity for ease of application of the acrylate coating composition.

[0259] The different acrylate coating compositions have been used to produce acrylate coating layers as described in the examples that follow. In some of these examples, use has been made of a second acrylate coating composition.

[0260] The composition of the second acrylate coating composition used in the examples:

[0261] - 14.4 parts by weight of a trifunctional epoxy acrylate oligomer,

[0262] - 35 parts by weight of a polyester methacrylate oligomer,

[0263] - 15 parts by weight of an unsaturated polyester acrylate oligomer,

[0264] - 30 parts by weight of an acrylate reactive diluent having three acrylate functionalities, - 0.1 parts by weight of Omnirad 2100, which is a blend of Norrish type I photo initiators,

[0265] - 0.2 parts by weight of Luperox 531M60 (Arkema) which is a 60% solution of 1,1- di(tert-amylperoxy)-cyclohexane peroxide in isododecane. l,l-di(tert-amylperoxy)- cyclohexane peroxide is a thermo-initiator having a 60 seconds half-life temperature of 152 °C.

[0266] - 0.3 parts by weight of thermo-initiator tert-butyl peroxy-3, 5, 5 -trimethylhexanoate (TBPIN - CAS 13122-18-4), which has a 60 seconds half-life temperature of 160°C.

[0267] - 0.3 parts by weight of thermo-initiator 2-5-dimethyl-2-5-di-tert-butylperoxy-hexane, which has a 60 seconds half-life temperature of 177 °C.

[0268] - 0.3 parts by weight of thermo-initiator 2,5-dimethyl-2,5-bis(t-butyl peroxy)hexyne- 3,85% solution in white oil. This thermo-initiator has a 60 seconds half-life temperature of 194°C.

[0269] This composition of the second acrylate coating composition is given as an example; other acrylate coating compositions can be used as second acrylate coating composition.

[0270] In a first example, 170 gram per square meter of the exemplary second acrylate coating composition has been applied onto a resin impregnated printed sheet of paper. This coating layer has been pre-gelled using UV-radiation. Using a roller coating applicator, 40 gram per meter (dry solids weight) of acrylate coating composition 1A has been applied onto the pre-gelled acrylate coating layer, followed by one minute in an oven at 120 °C or two minutes in an oven at 100 °C, thereby obtaining a non-tacky surface of the coated resin impregnated printed sheet of paper.

[0271] This coated resin impregnated printed sheet of paper is laminated to a wood fiber board (a HDF board - High Density Fiberboard) in a short cycle press (during 30 seconds at 200 °C using a pressure of 80 kg per square centimeter) in which the coating layer is embossed (thanks to the use of a structured press element) and thermally cured by thermally induced addition reactions of the acrylate double bonds in the coating layer, thanks to the presence of the thermo-initiators in the acrylate coating composition and in the exemplary second acrylate coating composition.

[0272] In the same way as with acrylate coating composition 1A, decorative panels have been made with acrylate coating composition IB, with acrylate coating composition 1C, with acrylate coating composition 2, with acrylate coating composition 3, with acrylate coating composition 4, with acrylate coating composition 5 and with acrylate coating composition 6.

[0273] In an example, 170 gram per square meter of the exemplary second acrylate coating composition has been applied onto a resin impregnated printed sheet of paper. This coating layer has been pre-gelled using UV-radiation. Using a roller coating applicator, 25 gram per meter (dry solids weight) of acrylate coating composition 1A has been applied onto the pre-gelled acrylate coating layer, followed by one minute in an oven at 120 °C, thereby obtaining a non-tacky surface of the coated resin impregnated printed sheet of paper.

[0274] This coated resin impregnated printed sheet of paper is laminated to a wood fiber board (a HDF board - High Density Fiberboard) in a short cycle press (during 30 seconds at 200 °C using a pressure of 80 kg per square centimeter) in which the coating layer is embossed (thanks to the use of a structured press element) and thermally cured by thermally induced addition reactions of the acrylate double bonds in the coating layer, thanks to the presence of the thermo-initiators in the acrylate coating composition and in the exemplary second acrylate coating composition.

[0275] In an example, 170 gram per square meter of the exemplary second acrylate coating composition has been applied onto a resin impregnated printed sheet of paper. This coating layer has been pre-gelled using UV-radiation. Using a roller coating applicator, 25 gram per meter (dry solids weight) of acrylate coating composition 4 has been applied onto the pre-gelled acrylate coating layer, followed by a partial UV-radiation curing, thereby obtaining a non-tacky surface of the coated resin impregnated printed sheet of paper.

[0276] This coated resin impregnated printed sheet of paper is laminated to a wood fiber board (a HDF board - High Density Fiberboard) in a short cycle press (during 30 seconds at 200 °C using a pressure of 80 kg per square centimeter) in which the coating layer is embossed (thanks to the use of a structured press element) and thermally cured by thermally induced addition reactions of the acrylate double bonds in the coating layer, thanks to the presence of the thermo-initiators in the acrylate coating composition and in the exemplary second acrylate coating composition.

[0277] In an example of the invention, 180 gram per square meter of acrylate coating composition 3 has been applied on a resin impregnated printed sheet of paper. The acrylate coating layer is dried in an oven at 120°C. Optionally, a UV-curing shot can be given. The acrylate coating layer obtained is tack free. The coated impregnated printed sheet of paper can be used in a thermal pressing operation to provide an embossed decorative layer to a panel as mentioned in the other examples.

[0278] In an example of the invention, 80 gram per square meter of acrylate coating composition 5 has been applied on a resin impregnated printed sheet of paper. The acrylate coating layer is dried in an oven at 120°C, thereby obtaining a tack free coating layer. The coated impregnated printed sheet of paper can be used in athermal pressing operation to provide an embossed decorative layer to a panel as mentioned in the other examples. In an example of the invention, 80 gram per square meter of acrylate coating composition 4 has been applied on a resin impregnated printed sheet of paper. The application of the acrylate coating composition is followed by a UV-radiation, thereby obtaining a tack free coating layer. The coated impregnated printed sheet of paper can be used in a thermal pressing operation to provide an embossed decorative layer to a panel as mentioned in the other examples.

[0279] In an example of the invention, 100 gram per square meter of acrylate coating composition IB has been applied on a resin impregnated printed sheet of paper. The coated paper is passed through an oven. Thereafter, 25 gram per square meter of the exemplary second acrylate coating composition has been applied, and brought to non- tacky state using UV-radiation and excimer radiation. The coated impregnated printed sheet of paper can be used in a thermal pressing operation to provide an embossed decorative layer to a panel as mentioned in the other examples.

[0280] Figure 1 shows an example of a method according to aspects of the invention for manufacturing a decorative panel. The method comprises the step of providing a substrate, e.g. a board 10, which can e.g. be a wood-based board, a wood fiber board, a wood chip board, a mineral board - e.g. a magnesium oxide based board -, or a - whether or not filled - plastic board, e.g. a - whether or not filled - thermoplastic board.

[0281] An acrylate coated impregnated printed sheet of paper 12, e.g. the acrylate coated impregnated sheet of paper as in the examples mentioned above, is placed on the board 10.

[0282] A second sheet of paper 14 impregnated with a thermoset resin can be positioned at the other side of the board 10.

[0283] The stack of the acrylate coated impregnated printed sheet of paper 12, the board 10 and the second sheet of paper 14 is pressed at elevated temperature in a single daylight press 20. The press element of the singe daylight press 20 is in the example shown a structured press element 22. In the single daylight press 20, the acrylate coated impregnated printed sheet of paper 12 and the second sheet of paper 14 are laminated to the board 10 thanks to the resins with which the acrylate coated impregnated printed sheet of paper 12 and the second sheet of paper 14 are impregnated. In the single daylight press, the acrylate coating layer of the acrylate coated impregnated printed sheet of paper 12 is embossed (as the acrylate coating layer has previously only been partially cured, such that it can still flow under the influence of pressure and heat) in which the texture of the structured press element 22 is copied and the acrylate coating layer is thermally cured. Using an appropriate structured press element 22 and correct positioning of the acrylate coated impregnated printed sheet of paper 12, an embossment in register with the printed design of the acrylate coated impregnated printed sheet of paper 12 can be obtained. The press element can also provide a pressed bevel to the decorative panel.

[0284] In the thermal pressing operation, the acrylate coating layer of the acrylate coated impregnated printed sheet of paper 12 is cured. The curing is initiated by the presence of the thermo-initiator(s) in the acrylate coating layer, resulting in addition reactions of the acrylate double bonds of the acrylate coating layer of the acrylate coated impregnated printed sheet of paper 12.

[0285] The second sheet of paper 14 can provide a balancing layer to the decorative panel which is obtained in the described thermal pressing operation.

[0286] With the method of figure 1, a decorative panel 30 as shown in figure 2 can be obtained. The decorative panel comprises a board 10, and an acrylate coated impregnated printed sheet of paper 12. The decorative panel is embossed with a texture in register with the printed decor of the printed sheet of paper. The bottom of the decorative panel 30 shown in the example comprises an impregnated second sheet of paper 14 acting as balancing layer.

[0287] The present invention is in no way limited to the embodiments described as examples and represented in the figures, on the contrary it can be realized in various forms and dimensions, without leaving the scope of the invention.

Claims

Claims1.- Acrylate coating composition for the application of a protective coating layer to a substrate, wherein the acrylate coating composition comprises at least an acrylate oligomer, wherein the coating composition comprises at least a component comprising at least one isocyanate group.2.- Acrylate coating composition as in claim 1, characterized in that the component comprising at least one isocyanate group is at least provided by the at least an acrylate oligomer being an acrylate oligomer, preferably a polyurethane acrylate oligomer, comprising at least one isocyanate group.3.- Acrylate coating composition as in any of the preceding claims, characterized in that the component comprising at least one isocyanate group is at least provided by a component selected from the list of an acrylate oligomer - preferably a polyurethane acrylate oligomer - comprising at least one isocyanate group, a di-isocyanate, a polyisocyanate, an isocyanate bearing unsaturated acrylic ester resin; or combinations thereof.4.- Acrylate coating composition as in any of the preceding claims, characterized in that the acrylate coating composition comprises a polyisocyanate; preferably an aliphatic polyisocyanate and / or preferably a hexamethylene diisocyanate (HDI) or an isophorone (IPDI) based polyisocyanate, or combinations thereof.5.- Acrylate coating composition as in claim 5, characterized in that the polyisocyanate has an isocyanate content of between 10 and 25 percent by weight.6.- Acrylate coating composition as in any of the preceding claims, characterized in that the acrylate coating composition comprises a hydroxy functional component, preferably wherein the hydroxy functional component is selected from one or more of - hydroxy functional acrylate resins,- hydroxy functional acrylate oligomers, preferably having a molar mass of at least 800 g / mol;- hydroxy functional polyester resins, preferably unsaturated hydroxy functional polyester resins;- hydroxy functional polyether resins (e.g. a trifunctional polyester acrylate);- hydroxy functional urethane acrylates, preferably hydroxy functional acrylate oligomers;- aliphatic polyols;- hydroxy functional unsaturated polyester acrylic resins;- hydroxy functional unsaturated polyester resin;- one or more hydroxy functional mono, di, tri, tetra or penta acrylate functional reactive diluents preferably having a molar mass lower than 1000 g / mol, and more preferably lower than 600 g / mol; or combinations thereof.7.- Acrylate coating composition, optionally an acrylate coating composition as in any of the preceding claims, characterized in that the acrylate coating composition comprises a hydroxy functional acrylate oligomer, preferably a hydroxy functional acrylate acrylic oligomer.8.- Acrylate coating composition as in claim 7, characterized in that het acrylate coating composition does not comprises isocyanate groups.9.- Acrylate coating composition as in any of the preceding claims 1 - 8, characterized in that the acrylate coating composition does not comprise acrylate reactive diluents, wherein acrylate reactive diluents are defined as diluents comprising at least one acrylate group and having a molar mass lower than 1000 g / mol, and preferably lower than 600 g / mol.10.- Acrylate coating composition as in any of the preceding claims 1 - 8, characterized in that the acrylate coating composition comprises acrylate reactive diluents having a molar mass lower than 1000 g / mol (and preferably lower than 600g / mol), preferably in an amount less than 50 wt% - and preferably in an amount less than 40 wt% - of the acrylate coating composition.11.- Acrylate coating composition as claim 10, characterized in that the acrylate coating composition comprises one or more mono, di, tri, tetra or penta acrylate functional reactive diluents preferably having a molar mass lower than 1000 g / mol, and more preferably lower than 600 g / mol; and / or one or more mono, di, tri, tetra or penta acrylate functional acrylic acid esters preferably having a molar mass lower than 1000 g / mol, and more preferably lower than 600 g / mol12.- Acrylate coating composition as in any of the preceding claims 10 - 11, characterized in that the acrylate coating composition comprises one more hydroxy functional mono, di, tri or tetra acrylate functional reactive diluents, preferably selected from the list of 4-(ethenyloxy)-l -butanol (HBVE), pentaerythritol triacrylate (PETIA), dipentaerythritol pentaacrylate (DiPEPA), 2-hydroxypropyl methacrylate (HPMA), (hydroxyethyl)methacrylate (HEMA), 4-hydroxybutyl acrylate (4-HBA); or combinations thereof.13.- Acrylate coating composition as in any of the preceding claims, characterized in that the acrylate coating composition comprises non-reactive solvent, preferably wherein the amount of non-reactive solvent in the acrylate coating composition is between 5 and 60 wt%.14.- Acrylate coating composition as in claim 13, characterized in that the solvent is selected from an ester (e.g. butyl acetate, ethyl acetate, methoxypropyl acetate), a ketone (e.g. acetone, methyl ethyl ketone, methyl isobutyl ketone), an aromatic hydrocarbon (e.g. xylene); or mixtures thereof.15.- Acrylate coating composition as in any of the preceding claims 1 - 12, characterized in that the acrylate coating composition substantially does not comprise non-reactive solvent.16.- Acrylate coating composition as in any of the preceding claims, characterized in that the acrylate coating composition comprises a first thermo-initiator.17.- Acrylate coating composition as in claim 16, characterized in that the acrylate coating composition comprises a first thermo-initiator and a second thermo-initiator, wherein the 60 seconds half-life of the second thermo-initiator is at least 8°C higher than the 60 seconds half-life of the first thermo-initiator.18.- Acrylate coating composition as in claim 17, characterized in that the acrylate coating composition comprises a third thermo-initiator, wherein the 60 seconds half-life of the third thermo-initiator is at least 8°C higher than the 60 seconds half-life of the second thermo-initiator.19.- Acrylate coating composition as in claim 18, characterized in that the acrylate coating composition comprises a fourth thermo-initiator, wherein the 60 seconds halflife of the fourth thermo-initiator is at least 8°C higher than the 60 seconds half-life of the third thermo-initiator.20.- Acrylate coating composition as in any of the preceding claims 1 - 19, characterized in that the acrylate coating composition comprises one or more than one photo-initiator.21.- Acrylate coating composition as in any of the preceding claims 1 - 19, characterized in that the acrylate coating composition does not comprise a photo-initiator.22.- Acrylate coating composition as in any of the preceding claims, characterized in that the acrylate coating composition comprises additives selected from one or more than one of abrasion resistant particles (e.g. aluminum oxide particles, diamond particles, silicon carbide particles), wetting agents, easy-to-clean particles.23.- Acrylate coating composition as in any of the preceding claims, characterized in that the acrylate coating composition comprises at least an isocyanate functional acrylateoligomer, preferably an isocyanate functional urethane acrylate oligomer, more preferably an isocyanate functional aliphatic urethane acrylate oligomer.24.- Acrylate coating composition as in claim 23, characterized in that the isocyanate functional acrylate oligomer has isocyanate functionality at least 2, and preferably at least 2.2, more preferably at least 2.4.25.- Acrylate coating composition as in any of the preceding claims 23 - 24, characterized in that the isocyanate content of the isocyanate functional acrylate oligomer is between 3 and 25 wt%.26.- Acrylate coating composition as in any of the preceding claims 23 - 25, characterized in that the isocyanate functional acrylate oligomer has acrylate functionality at least 0.7, preferably at least 1, more preferably at least 2, more preferably at least 2.2.27.- Acrylate coating composition as in any of the preceding claims, characterized in that the acrylate coating composition comprises a crosslinker, preferably selected from the list consisting of isocyanate, carbodiimide, aziridine, and combinations thereof.28.- Acrylate coating composition as in any of the preceding claims, characterized in that the acrylate coating composition comprises a catalyst, e.g. a metallic component, preferably a tin component, e.g. dibutyltin dilaurate (DBTL) or dioctyltin dilaurate; or bismuth carboxylate, or zinc carboxylate, or chelates of zirconium or aluminum.29.- Acrylate coating composition as in any of the preceding claims, characterized in that the acrylate coating composition comprises a catalyst, wherein the catalyst is a metal soap, preferably a sodium soap, a calcium soap, a bismuth soap or a zinc soap (e.g. zinc neodecanate), or combinations thereof; and / or preferably an unsaturated metal soap, preferably an unsaturated sodium soap, an unsaturated calcium soap, an unsaturated bismuth soap or an unsaturated zinc soap.30.- Acrylate coating composition as in any of the preceding claims, characterized in that the acrylate coating composition comprises at least 35 wt% of acrylate oligomer, wherein the acrylate oligomer has molecular mass at least 800 g / mol.31.- Acrylate coating composition as in any of the preceding claims, characterized in that the acrylate coating composition comprises a urethane acrylate oligomer having isocyanate functionality and molar mass at least 800 g / mol, and one or more of- an oligomer - preferably an acrylate oligomer, more preferably a urethane acrylate oligomer -, preferably having molar at least 800 g / mol, having hydroxyl functionality, or,- a reactive diluent, preferably an acrylate reactive diluent, having hydroxyl functionality, preferably wherein the reactive diluent has molar mass less than 600 g / mol, or- a polyester acrylate having hydroxyl functionality.32.- Acrylate coating composition as in any of the preceding claims, characterized in that the acrylate coating composition comprises a urethane acrylate oligomer - preferably having molar mass higher than 1000 g / mol - having hydroxyl functionality, and an oligomer - preferably a urethane acrylate oligomer - having isocyanate functionality.33.- Acrylate coating composition as in any of the preceding claims, characterized in that the acrylate coating composition comprises a phosphonate adhesion promotor.34.- Acrylate coating composition as in any of the preceding claims, characterized in that the acrylate coating composition comprises a matting agent, preferably wherein the matting agent provides between 2 and 14 wt% - and more preferably between 3 and 10 wt% - of the acrylate coating composition.35.- Acrylate coating composition as in claim 34, characterized in that the matting agent is an amorphous silica, preferably having S50 particle size according to volume between 3 and 20 micrometer.36.- Method for applying an acrylate coating to a substrate, wherein the method comprises the steps of- providing a substrate;- providing an acrylate coating composition as in any of the preceding claims;- applying the acrylate coating composition to the substrate thereby obtaining an acrylate coating layer on the substrate;- processing the acrylate coating layer to non-tacky state; wherein the step of processing the acrylate coating layer to non-tacky state comprises the step of increasing the temperature of the acrylate coating layer (preferably to a temperature of at least 60 °C and preferably to a temperature less than 140°C); and / or the step of irradiating the acrylate coating layer with UV-radiation.37.- Method as in claim 36, characterized in that the step of increasing the temperature of the acrylate coating layer is performed at least by means of a hot air oven, or by means of infrared radiation, or by means of microwave radiation, or by means of combinations thereof, thereby partially curing the acrylate coating layer to non-tacky state.38.- Method as in any of the preceding claims 36 - 37, characterized in that in the step of increasing the temperature of the acrylate coating layer, isocyanate groups of the at least a component comprising at least one isocyanate group react with hydroxyl groups present in the acrylate coating composition and / or in the substrate.39.- Method as in any of the preceding claims 36 - 38, characterized in that the non- tacky state of the acrylate coating layer is a state which allows that the acrylate coating layer is embossed and cured in a thermal pressing operation.40.- Method as in any of the preceding claims 36 - 39, characterized in that the method does not comprise irradiation of the acrylate coating layer with UV-radiation nor with electron beam radiation for processing the acrylate coating layer to non-tacky state.41.- Method as in any of the preceding claims 36 - 39, characterized in that the step of processing the acrylate coating layer to non-tacky state comprises the step ofirradiating the acrylate coating layer with UV-light (e.g. using UV-lamps, using UV- LED, using excimer radiation, or combinations thereof) and / or electron beam radiation.42.- Method as in claim 41, characterized in that the step of irradiating the acrylate coating layer is performed after the step of the step of increasing the temperature of the acrylate coating layer.43.- Method as in any of the preceding claims 36 - 42, characterized in that the acrylic coating composition comprises a non-reactive solvent and that the non-reactive solvent is evaporated in the step of increasing the temperature of the acrylate coating layer.44.- Method as in any of the preceding claims 36 - 43, characterized in that the acrylate coating layer has a dry weight between 30 and 300 gram per square meter.45.- Method as in any of the preceding claims 36 - 44, characterized in that the method comprises the step of at least partially - and preferably to substantially fully cured state - curing the non-tacky acrylate coating layer by means of a thermal pressing operation.46.- Method as in claim 45, characterized in that the acrylate coating composition comprises at least one thermo-initiator; wherein in the thermal pressing operation the at least one thermo-initiator initiates an addition reaction of acrylate double bonds.47.- Method as in claims 45 - 46, characterized in that in the thermal pressing operation the acrylate coating layer is provided with a texture, preferably a texture in register with a printed decor of the substrate; more preferably wherein in the thermal pressing operation the acrylate coating layer copies the texture and gloss of the textured pressing element.48.- Method as in any of the preceding claims 45 - 47, characterized in that the acrylate coating layer is subjected to a radiation curing step - preferably by means of UV- radiation or by means of electron beam radiation - performed after the step of at least partially curing the acrylate coating layer by means of the thermal pressing operation.49.- Method as in any of the preceding claims 435- 47, characterized in that the acrylate coating layer is not subjected to a radiation curing step after the step of at least partially curing the acrylate coating layer by means of the thermal pressing operation.50.- Method as in any of the preceding claims 45 - 49, characterized in that in the thermal pressing operation, the substrate is laminated to a board.51.- Method as in any of the preceding claims 36 - 450, characterized in that the method comprises the steps of- providing a second acrylate coating composition;- applying the second acrylate coating composition to the substrate;- partially curing the second acrylate coating composition applied to the substrate by means of UV-radiation (e.g. by means of UV-lamps, by means of UV-LED or by means of excimer radiation - but preferably without excimer radiation) or electron beam radiation;- wherein the steps of applying the second acrylate coating composition to the substrate and partially curing the second acrylate coating composition are performed before the step of applying the acrylate coating composition to the substrate;- wherein the second acrylate coating composition comprises one or more acrylate oligomers (preferably wherein said oligomers have a molar mass equal to or higher than 800 g / mol, and preferably higher than 1000 g / mol, and preferably lower than 10000 g / mol) and one or more acrylate reactive diluents having a molar mass lower than 1000 g / mol, and preferably lower than 800 g / mol.52.- Method as in claim 51, characterized in that the amount of dry weight per square meter applied of the second acrylate coating composition is higher than - and preferably at least double - the amount of dry weight per square meter applied of the acrylate coating composition.53.- Method as in any of the preceding claims 51 - 52, characterized in that option 1 or option 2 is fulfilled:- option 1 : the second acrylate coating composition does not comprise abrasion resistance increasing particles whereas the acrylate coating composition does comprise abrasion resistance increasing particles;- option 2: the second acrylate coating composition and the acrylate coating composition both comprise abrasion resistance increasing particles, wherein the average particle size by number of the abrasion resistance increasing particles of the acrylate coating composition is smaller than the average particle size by number of the abrasion resistance increasing particles of the second acrylate coating composition.54.- Method as in any of the preceding claims 36 - 50, characterized in that after applying the acrylate coating composition and processing the acrylate coating layer to non-tacky state; a second acrylate coating composition is applied, thereby providing the substrate with a second acrylate coating layer;- wherein the second acrylate coating composition comprises one or more acrylate oligomers (preferably wherein said oligomers have a molar mass equal to or higher than 800 g / mol and lower than 7000 g / mol) and one or more acrylate reactive diluents having a molar mass lower than 1000 g / mol.55.- Method as in claim 54, characterized in that the after its application, the second acrylate coating composition is partially cured by means of UV-radiation (e.g. by means of UV-lamps, by means of UV-LED or by means of excimer radiation - but preferably without excimer radiation) or electron beam radiation to non-tacky state.56.- Method as in any of the preceding claims 54 - 55, characterized in that the dry weight applied per square meter of the second acrylate coating composition is less than the dry weight applied per square meter of the acrylate coating composition, preferably the dry weight applied of the second acrylate coating composition is less than 30% of the dry weight applied of the acrylate coating composition.57.- Method as in any of the preceding claims 54 - 56, characterized in that option 1 or option 2 is fulfilled:- option 1 : the acrylate coating composition does not comprise abrasion resistanceincreasing particles whereas the second acrylate coating composition does comprise abrasion resistance increasing particles;- option 2: the acrylate coating composition and the second acrylate coating composition both comprise abrasion resistance increasing particles, wherein the average particle size by number of the abrasion resistance increasing particles of the second acrylate coating composition is smaller than the average particle size by number of the abrasion resistance increasing particles of the acrylate coating composition.58.- Method as in any of the preceding claims 51 - 75, characterized in that the second acrylate coating composition comprises a photo-initiator.59.- Method as in any of the preceding claims 51 - 58, characterized in that the second acrylate coating composition does not comprise non-reactive solvents.60.- Method as in any of the preceding claims 51 - 59, characterized in that the acrylate oligomers of the second acrylate coating composition are selected from polyester acrylates (preferably having acrylate functionality of at least 3), urethane acrylates, epoxy acrylates, unsaturated polyester acrylates, unsaturated polyester, and combinations thereof.61.- Method as in any of the preceding claims 51 - 60, characterized in that the average acrylate functionality of the acrylate reactive diluents of the second acrylate coating composition is at least 2, preferably at least 2.5, more preferably at least 2.8.62.- Method as in any of the preceding claims 51 - 61, characterized in that the second acrylate coating composition comprises a first thermo-initiator.63.- Method as in any of the preceding claims 51 - 62, characterized in that the second acrylate coating composition comprises a first thermo-initiator and a second thermoinitiator, wherein the 60 seconds half-life of the second thermo-initiator is at least 8°C higher than the 60 seconds half-life of the first thermo-initiator.64.- Method as in claim 63, characterized in that the second acrylate coating composition comprises a third thermo-initiator, wherein the 60 seconds half-life of the third thermo-initiator is at least 8°C higher than the 60 seconds half-life of the second thermo-initiator.65.- Method as in claim 64, characterized in that the second acrylate coating composition comprises a fourth thermo-initiator, wherein the 60 seconds half-life of the fourth thermo-initiator is at least 8°C higher than the 60 seconds half-life of the third thermo-initiator.66.- Method as in any of the preceding claims 51 - 65, characterized in that the second coating composition does not comprise acrylate oligomers having isocyanate groups nor acrylate oligomers having hydroxyl groups.67.- Method as in any of the preceding claims 51 - 66, characterized in that the second coating composition does not comprise reactive diluents having isocyanate groups nor reactive diluents having hydroxyal groups.68.- Method as in any of the preceding claims 36 - 67, characterized in that the substrate is selected from the list consisting of an impregnated sheet of paper (and preferably an impregnated printed sheet of paper), a polymer film (and preferably a printed polymer film or a transparent polymer film - e.g. a PVC-film), a wood based board, a wood fiber board, a wood chip board, an engineered wood board, a plywood board, a veneer layer, a magnesium oxide based board, a cement based board, a gypsum board, or a stack of resin impregnated kraft sheet of paper.69.- Method as in any of the preceding claims 36 - 67, characterized in that the substrate comprises or consists of an impregnated sheet of paper (and preferably an impregnated printed sheet of paper), wherein the impregnated sheet of paper is impregnated with one or more of an aminoplast resin (e.g. a urea formaldehyde resin or a melamine formaldehyde resin or a melamine urea formaldehyde resin), an acrylate resin (preferably applied as an acrylate dispersion), a polyurethane resin (preferablyapplied as a polyurethane dispersion, more preferably as a UV-curable polyurethane dispersion), a reactive acrylate resin; or combinations thereof.70.- Method as in claim 69, characterized in that the impregnated sheet of paper comprises 35 - 135 wt% of dry resin calculated on the unimpregnated weight of the sheet of paper.71.- Method as in any of the preceding claims 69 - 70, characterized in that the moisture content of the impregnated sheet of paper is less than 8 wt%, preferably less than 7 wt%, more preferably less than 6 wt%.72.- Method as in any of the preceding claims 69 -71, characterized in that the impregnated sheet of paper comprises an adhesion layer on the side onto which the acrylate coating layer will be applied, preferably wherein the adhesion layer is selected from an acrylate layer (preferably applied as an acrylate dispersion), a melamine acrylate layer, a polyurethane layer, a polyurethane layer with acrylate functionality; or combinations thereof.73.- Method as in claim 72, characterized in that the adhesion layer has a dry weight between 4 and 30 gram per square meter.74.- Method as in any of the preceding claims 69 - 73, characterized in that the impregnated sheet of paper comprises an adhesion layer on the side opposite to the side onto which the acrylate coating layer will be applied, preferably wherein the adhesion layer is selected from an aminoplast resin (e.g. a urea formaldehyde resin or a melamine urea formaldehyde resin), an acrylate layer (preferably applied as an acrylate dispersion), a melamine acrylate layer, a polyurethane layer, a polyurethane layer with acrylate functionality; or combinations thereof.75.- Method as in claim 74, characterized in that the adhesion layer has a dry weight between 4 and 30 gram per square meter.76.- Coated substrate, characterized in that the coated sub state comprises a substrate, wherein the substrate is provided with an acrylate coating layer applied using an acrylate coating composition as in any of the preceding claims 1 - 35, wherein the acrylate coating layer comprises urethane bonds, wherein the acrylate coating layer is not tacky, wherein the acrylate coating layer comprises acrylate double bonds.77.- Coated substrate as in claim 76, characterized in that the substrate is selected from the list consisting of an impregnated sheet of paper (and preferably an impregnated printed sheet of paper), a polymer film (and preferably a printed polymer film or a transparent polymer film - e.g. a PVC-film), a wood based board, a wood fiber board, a wood chip board, an engineered wood board, a plywood board, a veneer layer, a magnesium oxide based board, a cement based board, a gypsum board, or a stack of resin impregnated kraft sheet of paper.78.- Coated substrate as in any of the preceding claims 76 - 77, characterized in that the substrate comprises or consists of an impregnated sheet of paper (and preferably an impregnated printed sheet of paper), wherein the impregnated sheet of paper is impregnated with one or more of an aminoplast resin (e.g. a urea formaldehyde resin or a melamine formaldehyde resin or a melamine urea formaldehyde resin), an acrylate resin (preferably applied as an acrylate dispersion), a polyurethane resin (preferably applied as a polyurethane dispersion, more preferably as a UV-curable polyurethane dispersion), a reactive acrylate resin; or combinations thereof.79.- Coated substrate as in any of the preceding claims 76 - 78, characterized in that the acrylate coating layer comprises a first thermo-initiator.80.- Coated substrate as in claim 79, characterized in that the acrylate coating layer comprises a first thermo-initiator and a second thermo-initiator, wherein the 60 seconds half-life of the second thermo-initiator is at least 8°C higher than the 60 seconds half-life of the first thermo-initiator.81.- Coated substrate as in claim 80, characterized in that the acrylate coating layer comprises a third thermo-initiator, wherein the 60 seconds half-life of the third thermoinitiator is at least 8°C higher than the 60 seconds half-life of the second thermo-initiator. 82.- Coated substrate as in claim 81, characterized in that the acrylate coating layer comprises a fourth thermo-initiator, wherein the 60 seconds half-life of the fourth thermo-initiator is at least 8°C higher than the 60 seconds half-life of the third thermoinitiator. 83.- Coated substrate as in any of the preceding claims 76 - 82, characterized in that the acrylate coating layer is configured such that in a thermal pressing operation the acrylate coating layer can be embossed by copying the texture of a texture press element and thermally cured.

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