Acrylate coating composition

Abstract

An acrylate coating composition comprises (A) one or more oligomers selected from the group consisting of polyester acrylates and polyester methacrylates, or mixtures thereof; (B) one or more acrylate reactive diluents having a molar mass lower than 800 g / mol; (C) one or more photo initiators; and (D) one or more thermo initiators.

Description

[0001] Acrylate coating composition

[0002] The invention relates to an acrylate coating composition. The invention also relates to an acrylate coating composition that can be partially cured by means of radiation followed by thermal curing in which a texture can be pressed in the coating layer obtained with the acrylate coating composition.

[0003] W02020 / 095196A1 relates to a coated panel with at least a substrate and a top layer applied on the substrate. The top layer comprises at least a decor layer and a translucent or transparent wear layer. The wear layer comprises a thermally cured acrylate resin or a thermally cured unsaturated polyester resin. The thermal curing cures the resin partially or completely. The translucent or transparent wear layer can comprise an embossed relief.

[0004] WO202 1 / 224843 Al relates to a partially cured coated sheet. The sheet 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. The coating layer can be an acrylate coating layer. Methods are disclosed to manufacture such sheets; and to produce a decorative panel using such sheets.

[0005] WO2023 / 072891 Al discloses a radical-curable coating composition comprising (A) one or more oligomers selected from the group consisting of urethane (meth) acrylates, (meth)acrylated epoxidized triglycerides and any mixture thereof, wherein the oligomers have a molar mass equal to or higher than 800 g / mol and lower than 4500 g / mol, (B) one or more methacrylate reactive diluents having a molar mass lower than 800 g / mol, wherein the methacrylate reactive diluents have an average methacrylate functionality higher than 2, (C) one or more acrylate reactive diluents having a molar mass lower than 800 g / mol, wherein the acrylate reactive diluents have an average acrylate functionality higher than 2, (D) one or more photo-initiators, and (E) one or more thermal initiators, wherein the acrylate functionalities of the acrylate reactive diluents (C) and the methacrylate functionalities of the methacrylate reactive diluents (B) are present in a molar ratio of the acrylate functionalities to the methacrylate functionalities of at least 0.2, wherein the amount of oligomers (A) is higher than 20 wt.% and lower than 90 wt.% and the amount of reactive diluents (B) and (C) is higher than 10 wt.% and lower than 80 wt.%, based on the total amount of (A), (B) and (C), and wherein the total amount of

[0006] (A), (B) and (C) is at least 25 wt.% of the radical-curable coating composition.

[0007] Coating compositions comprising a high amount of urethane (meth) acrylates have a high reactivity which can result in processing problems when the coating obtained from such coating compositions is pre-gelled.

[0008] It is an object of the invention to provide improved acrylate coating compositions.

[0009] It is an object of the invention to provide improved acrylate coating composition which can after application to a carrier or substrate be partially radiation cured to non-tacky states, and be cured afterwards in a thermal pressing operation in which a texture can be pressed in the coating layer obtained from the improved acrylate coating composition.

[0010] The first aspect of the invention relates to an acrylate coating composition,. The coating composition comprises

[0011] (A) one or more oligomers selected from the group consisting of polyester acrylates and polyester methacrylates, or mixtures thereof;

[0012] (B) one or more acrylate reactive diluents having a molar mass lower than 800 g / mol, and preferably lower than 500 g / mol;

[0013] (C) one or more photo initiators; and

[0014] (D) one or more thermo initiators.

[0015] It is a benefit of the invention that an acrylate coating composition is provided that can be applied on a substrate and pre-gelled (partially cured) to an non-tacky state, e.g. using radiation energy (e.g. UV-radiation - monochromatic UV-radiation, possibly in combination with multichromatic UV-radiation). Afterwards, via thermal pressing the coating layer can be thermally cured, wherein the thermal pressing operation can provide a relief structure in the coating layer.

[0016] It is a particular benefit of the coating composition that the processing window during partial curing using radiation energy in order to partially cure the coating composition to non-tacky condition is broad. This facilitates the partial curing.

[0017] Preferably, the oligomers have a molar mass equal to or higher than 800 g / mol and lower than 7000 g / mol, more preferably lower than 4500 g / mol.

[0018] As used in this document, the molar mass of a compound 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. When the exact structural formula of a compound 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.

[0019] Preferably, the one or more oligomers comprise polyester acrylates and polyester methacrylates. More preferably, the percentage by weight of the polyester methacrylate oligomers in the combination of the one or more polyester acrylate oligomers and polyester methacrylate oligomers is at least 30%, more preferably at least 40%, even more preferably at least 50%.

[0020] The use of polyester methacrylate oligomers is preferred as it results in a coating that is more resistant to yellowing and staining.

[0021] A preferred embodiment is characterized in that the polyester acrylate oligomers comprise or consist of polyester acrylate oligomers having an acrylate functionality of at least 3 and / or in that the polyester methacrylate oligomers comprise or consist of polyester methacrylate oligomers having an methacrylate functionality of at least 3. Such embodiments provide coatings with excellent durability. In the context of this document, the acrylate or methacrylate functionality of a compound is the number of respectively acrylate or methacrylate groups per molecule of the compound. The acrylate functionality of a compound comprising different types of molecules not necessarily having the same acrylate (or methacrylate) functionality is determined as the molar based weighed average.

[0022] A preferred acrylate coating composition is characterized in that the amount of oligomers (A) in the coating composition is higher than 20 wt% and preferably below 60 wt% of the total amount of the polyester (meth)acrylate oligomers (A) and the acrylate reactive diluents (B).

[0023] A preferred acrylate coating composition is characterized in that the amount of the one or more acrylate reactive diluents (B) is more than 35 wt% - and preferably less than 60 wt% - of the total amount of the polyester (meth)acrylate oligomers (A) and the acrylate reactive diluents (B).

[0024] Such embodiments have the benefit that curing of the coating layer by polymerization is facilitated, as the reactivity of the coating composition is high. Reactive diluents are less sterically hindered than oligomers, resulting in the higher reactivity of the coating composition.

[0025] A preferred acrylate coating composition is characterized in that the total amount of the polyester (meth)acrylate oligomers (A) and the acrylate reactive diluents (B) in the acrylate coating composition is at least 25 wt%, more preferably at least 35 wt%; even more preferably at least 55 wt%, even more preferably at least 65 wt%. Such embodiments provide durable coatings.

[0026] It is a benefit of such embodiments that curing using UV-radiation or electron beam radiation is slowed down such that the acrylate coating composition can be pre-gelled using UV-radiation or electron beam radiation, wherein in the pre-gelling operation a broad processing window can be used. At the same time, thermal curing of the pre-gelled acrylate coating composition is accelerated. It is especially believed that the acrylate reactive diluents provide a lot of thermal energy in the thermal curing step, which accelerates the thermal curing operation.

[0027] A preferred acrylate coating composition is characterized in that the average acrylate functionality of the acrylate reactive diluents (B) is at least 2, preferably at least 2.5, more preferably at least 2.8. With “average acrylate functionality” is meant molar weighted average. Such acrylate reactive diluents ensure excellent crosslinking of coating layers after the coating layers have been fully cured.

[0028] Dipropylene glycol diacrylate (DPGDA- CAS 57472-68-1) is an example of such acrylate reactive diluent that can be used in the invention.

[0029] A preferred acrylate coating composition is characterized in that the coating composition comprises one or more methacrylate reactive diluents having a molar mass lower than 800 g / mol; and preferably lower than 500 g / mol. Such embodiments have the benefit that the coating composition has high reactivity, and that the coating layers are resistant to yellowing.

[0030] More preferably, the average methacrylate functionality of the methacrylate reactive diluents is at least 2, and preferably at least 3.

[0031] Preferably, in the combination of polyester (meth)acrylate oligomers (A), the polyester acrylate reactive diluents and the polyester methacrylate reactive diluents (B); the polyester methacrylate reactive diluents amount for less than 5 wt%; and preferably less than 2 wt%. Such embodiments are favored in order to avoid too high reactivity in thermal pressing coating layers. Too high reactivity would make it more difficult to provide a relief in the coating layer by copying the texture of the structured press element during a thermal pressing operation.

[0032] A preferred acrylate coating composition is characterized in that the coating composition does not comprise methacrylate reactive diluents. Such embodiments are favored as methacrylate reactive diluents have a high reactivity, which could make it more difficult to press a relief in the coating layer during thermal pressing - in which the coating layer in thermally cured - of previously partially cured coating layer.

[0033] It is favored that the one or more oligomers selected comprise polyester methacrylates. It is a benefit of such embodiments that coating layers are obtained that are resistant to yellowing.

[0034] A preferred acrylate coating composition is characterized in that the coating composition comprises one or more urethane (meth) acrylate oligomers. Preferably, the amount of urethane (meth) acrylate oligomers is less than 10 wt%, more preferably less than 5 wt%, more preferably less than 2 wt% of the sum of the oligomers (A) and reactive diluents (B).

[0035] The addition of a limited amount of urethane (meth) acrylate oligomers in the acrylate coating composition results in an increased flexibility of coating layers obtained from the acrylate coating composition.

[0036] A preferred acrylate coating composition is characterized in that the polyester (meth)acrylate oligomers (A) comprise or consist of unsaturated polyester (meth)acrylate oligomers; and preferably unsaturated polyester acrylate oligomers. Such coating compositions have the benefit that more cross-linking can be obtained when curing the coating compositions, resulting in coating layers have better wear resistance.

[0037] Preferably, at least 20 wt% of the polyester (meth)acrylate oligomers (A) are unsaturated polyester (meth)acrylate oligomers; more preferably unsaturated polyester acrylate oligomers.

[0038] With unsaturated polyester (meth)acrylate oligomers is meant that the polyester backbone of the oligomer comprises one or more than one double bond per molecule, next to the presence of one or more than one of respectively acrylate or methacrylate groups per molecule of the oligomer. With saturated polyester (meth)acrylate oligomers is meant that the polyester backbone of the oligomer does not comprise double bonds, however, the oligomer comprises one or more than one of respectively acrylate or methacrylate groups per molecule of the oligomer.

[0039] Preferably, the polyester (meth)acrylate oligomers (A) comprise between 10 and 50 weight percent of unsaturated polyester (meth)acrylate oligomers. Such coating compositions have the benefit that optimal cross-linking can be obtained when curing the coating compositions, resulting in coating layers having better wear resistance.

[0040] A preferred acrylate coating composition is characterized in that the one or more oligomers comprise polyester acrylates and polyester methacrylates; wherein the weight ratio of the polyester acrylates to the polyester methacrylates is between 0.2 and 2.5.

[0041] Such embodiments provide a good balance between good reactivity, while reactivity is not too high such that during thermal pressing a relief can be pressed in the previously partially cured to non-tacky status coating layer.

[0042] As an example, the weight ratio in the oligomers of the polyester acrylates to the polyester methacrylates can be 0.6.

[0043] A preferred acrylate coating composition is characterized in that it comprises non- (meth)acrylate unsaturated polyester oligomers.

[0044] With non-(meth)acrylate unsaturated polyester oligomers is meant a polyester oligomer the backbone of which comprises one or more than one double bond per molecule, but whereby no acrylate and no methacrylate group is present in the oligomer;

[0045] A preferred acrylate coating composition is characterized in that the one or more oligomers selected from the group consisting of polyester acrylates and polyester methacrylates, or mixtures thereof (A) comprise saturated polyester (meth)acrylate oligomers as well as unsaturated polyester (meth)acrylate oligomers. Such embodiments ensure that a coating can be obtained that has excellent wear and scratch resistance while cracking of the coating layer during its curing is prevented.

[0046] Preferably, the weight ratio of saturated polyester (meth)acrylate oligomers to the unsaturated polyester (meth)acrylate oligomers is between 0.2 and 2.5; and more preferably between 1.5 and 0.5; more preferably between 1.2 and 0.8. Such embodiments ensure that a coating can be obtained that has excellent wear and scratch resistance while cracking of the coating layer during its curing is prevented.

[0047] A preferred acrylate coating composition is characterized in that the one or more thermo initiators comprise 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 - and preferably at least 10°C, more preferably at least 15°C - higher than the 60 seconds half-life of the first thermo initiator.

[0048] Such embodiment is beneficial, as it allows that in the thermal curing of a coating layer obtained from the acrylate coating composition (e.g. by means of a thermal pressing operation), the coating layer is gradually cured, resulting in a coating layer having better properties, e.g. mechanical properties such as wear resistance. Especially the formation of cracks in the coating layer is prevented.

[0049] More preferably, the one or more thermo initiators comprise a third thermo initiator, wherein the 60 seconds half-life of the third thermo initiator is at least 8°C - and preferably at least 10°C, more preferably at least 15°C - higher than the 60 seconds half- life of the second thermo initiator.

[0050] Such embodiment is beneficial, as it allows that in the thermal curing of a coating layer obtained from the acrylate coating composition (e.g. by means of a thermal pressing operation), the coating layer is gradually cured, resulting in a coating layer having better properties, e.g. mechanical properties such as wear resistance. Especially the formation of cracks in the coating layer is prevented. A preferred acrylate coating composition is characterized in that the one or more thermo initiators comprise a fourth thermo initiator, wherein the 60 seconds half-life of the fourth thermo initiator is at least 8°C - and preferably at least 10°C, more preferably at least 15°C - higher than the 60 seconds half-life of the third thermo initiator.

[0051] Such embodiment is beneficial, as it allows that in the thermal curing of a coating layer obtained from the acrylate coating composition (e.g. by means of a thermal pressing operation), the coating layer is gradually cured, resulting in a coating layer having better properties, e.g. mechanical properties such as wear resistance. Especially the formation of cracks in the coating layer is prevented.

[0052] A preferred acrylate coating composition is characterized in that the one or more photo initiators are present in the acrylate coating composition in an amount less than 1 wt% of the combination of the weight of the one or more oligomers selected from the group consisting of polyester acrylates and polyester methacrylates (A) and the one or more (meth)acrylate reactive diluents (B), more preferably less than 1 wt%, more preferably less than 0.1 wt%, more preferably less than 0.06 wt%, more preferably less than 0.04 wt% .

[0053] Such low amount of photo initiators can be used as the acrylate coating composition can be partially cured to non-tacky condition via radiation curing, after which a thermal pressing operation can be performed for curing the coating composition. The low amount of photo initiators ensure that the coating layer is not cured too much in the partial curing to non-tacky state; and limits the cost of the acrylate coating composition as photo initiators are expensive.

[0054] A preferred coating composition is characterized in that the one or more photo initiators comprise or consist of Norrish type I photo initiators. Norrish type I photo initiators are preferred as they allow to achieve thick coating layers.

[0055] More preferred photo initiators comprise or consist of multifunctional Norrish type I photo initiators. 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).

[0056] 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).

[0057] A preferred acrylate coating composition is characterized in that the coating composition comprises one or more than one of a propoxylated acrylate monomer, a propoxylated acrylate oligomer, an ethoxylated acrylate monomer, an ethoxylated acrylate oligomer, or combinations thereof; preferably in a combined amount of between 30 and 60 wt% of the combination of the weight of the one or more oligomers selected from the group consisting of polyester acrylates and polyester methacrylates (A) and the one or more (meth)acrylate reactive diluents (B).

[0058] Such embodiments have the benefit that after curing a coating layer is obtained that is more flexible. Furthermore, such additives have the benefit that the initial adhesion after applying the coating is improved.

[0059] An example of such additive that can be used in acrylate coating compositions according to the invention is ethoxylated (15) trimethylolpropane triacrylate.

[0060] The range mentioned is beneficial as optimized flexibility of the coating layer is obtained.

[0061] A preferred acrylate coating composition is characterized in that the coating composition comprises one or more epoxy acrylate oligomers, preferably with acrylate functionality 2 or at least 2. The use of epoxy acrylates in the acrylate coating composition has the benefit that the hardness of coating layers obtained from the coating composition is high, resulting in improved wear resistance of the coating layer.

[0062] Preferably, the amount of the epoxy acrylate oligomers is less than 20 wt% of the combination of the one or more oligomers selected from the group consisting of polyester acrylates and polyester methacrylates (A) and the one or more (meth)acrylate reactive diluents (B).

[0063] It is a benefit of keeping the amount of epoxy acrylate oligomers in the acrylate coating composition limited that yellowing of the cured coating layer obtained from the acrylate coating composition is minimized or even fully avoided.

[0064] A preferred acrylate coating composition is characterized in that the coating composition comprises silica (SiCh), preferably in an amount more than 0.05 wt of the total coating composition, and preferably less than 1 wt% of the coating composition.

[0065] Such embodiments are favored as in the process of pre-gelling the coating layer to non- tacky condition using excimer radiation or LED-radiation, a pre-gelled coating layer is obtained that results in more homogeneous coating surface when thermally pressing the coating layer in which the coating layer is provided with a relief by copying the texture of a structured press element and in which the coating layer is thermally cured.

[0066] The silica can be fumed silica or precipitated silica.

[0067] A preferred acrylate coating composition is characterized in that the coating composition comprises AI2O3 particles, preferably in an amount more than 0.05 wt of the total coating composition, and preferably less than 7 wt% (and more preferably less than 2 wt%) of the coating composition.

[0068] Such embodiments are favored as in the process of pre-gelling the coating layer to non- tacky condition using excimer radiation or LED-radiation, a pre-gelled coating layer is obtained that results in more homogeneous coating surface when thermally pressing the coating layer in which the coating layer is provided with a relief by copying the texture of a structured press element and in which the coating layer is thermally cured.

[0069] It has been observed that acrylate coating compositions according to the invention are less thermally conductive than traditionally used melamine resins. Less good thermal conductivity can lead to temperature differences in the acrylate coating layer during thermal pressing operations. The AI2O3 particles are believed to act as thermal conductor, such that the during a thermal pressing operation in which the acrylate coating is cured the temperature is more uniform over the thickness of the coating layer, as evidenced by thermocouple measurements. As the temperature is more uniform, less stress is built up in the acrylate coating layer, resulting in less cracks and therefore an acrylate coating layer of better quality.

[0070] A preferred acrylate coating composition is characterized in that the coating composition comprises wear resistant particles, e.g. corundum or silicon carbide. Such embodiments provide coating layers with increased scratch resistance.

[0071] A preferred acrylate coating composition is characterized in that the coating composition comprises inert beads, preferably inert acrylic beads or polyurethane beads or poly(methyl methacrylate) (PMMA) beads

[0072] Preferably, the inert beads have a glass transition temperature (Tg) of at least 80°C, more preferably of at least 100 °C, even more preferably of at least 150 °C.

[0073] The glass transition temperature in the context of this document is determined using DSC (Differential Scanning Calorimetry) with heating rate 20 °C / minute as the flex point of the phase transition.

[0074] Preferably, the acrylate coating composition comprises between 5 and 35 wt% inert beads relative to the combination of the one or more oligomers selected from the group consisting of polyester acrylates and polyester methacrylates (A) and the one or more (meth)acrylate reactive diluents (B).

[0075] It is a benefit of the incorporation of the inert beads in the coating composition that a cheap filler is used which improves the overall glass transition temperature (Tg) of coatings obtained from the acrylate coating composition. Furthermore, the incorporation of the inert beads improves the toughness of the coating, which is beneficial for the wear resistance of coating layers obtained from the acrylate coating composition. The incorporation of the inert beads in the acrylate coating composition of the invention is easier than the incorporation of such inert beads in coating compositions based on urethane acrylate oligomers thanks to the lower viscosity of polyester (meth)acrylate oligomers compared to urethane acrylate oligomers.

[0076] A preferred acrylate coating composition is characterized in that the combination of the one or more photo initiators (C) and the one or more thermo initiators (D) relative to the total amount of the combination of the one or more oligomers selected from the group consisting of polyester acrylates and polyester methacrylates (A) and the one or more acrylate reactive diluents (B) is less than 1 wt%, preferably less than 0.5 wt%.

[0077] The amount of photo initiators can be kept low as the coating composition can be first partially cured (e.g. using excimer radiation or LED-radiation) under inert atmosphere (e.g. under nitrogen atmosphere). As the coating layer can be thermally cured in a thermal pressing operation, the closed press avoids oxygen at the coating layer, such that oxygen inhibition is prevented. As a consequence, the amount of thermo initiators can be kept low.

[0078] A preferred acrylate coating composition is characterized in that the acrylate coating composition comprises pigments or dyes, preferably in an amount of 0.5 - 10 wt% relative to the total weight of the acrylate coating composition.

[0079] A preferred acrylate coating composition is characterized in that it results after full curing in a transparent coating layer. A preferred acrylate coating composition 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 second aspect of the invention relates to a coating layer. The coating layer is characterized in that the coating layer is obtained from a coating composition as in any embodiment of the first aspect of the invention.

[0084] The coating layer preferably has a mass between 50 and 300 g / m2; more preferably of more than 100 g / m2; preferably more preferably between 120 and 160 g / m2. Such coating layers result in excellent abrasion and wear resistance of the fully cured coating layer; and can be deeply embossed e.g. for imitating the texture of a wood panel.

[0085] The third aspect of the invention relates to a decorative panel. The decorative panel is characterized in that the decorative panel comprises a substrate, and a top layer. The top layer comprises a printed decor and a coating layer. The coating layer is a coating layer obtained from a coating composition as in any embodiment of the first aspect of the invention; and / or a coating layer according to the second aspect of the invention.

[0086] The coating layer preferably has a mass between 100 and 300 gram per square meter of the surface of the decorative panel.

[0087] Such embodiments have the benefit that they be embossed, provided with a deep surface structure. A combination of matt and glossy sections in the coating layer is possible.

[0088] A preferred decorative panel is characterized in that the top layer comprises a resin impregnated paper sheet comprising the printed decor. More preferably, the coating layer contacts the resin impregnated paper sheet.

[0089] The impregnated printed paper sheet can comprise a primer onto which the coating layer is applied. Preferably, the primer comprises resins selected from the list of polyurethane, polyurethane with acrylate functionalities, melamine formaldehyde resin; or combinations thereof.

[0090] The primer has the benefit that proper adhesion is ensured between the impregnation resin and the acrylate coating layer applied on resin impregnated paper sheet comprising the printed decor.

[0091] The primer might be applied as a water-based polyurethane dispersion and / or as a waterbased polyurethane dispersion containing acrylate functionalities; and / or a melamine primer; and / or mixtures thereof. The top layer can comprise a printed plastic foil. More preferably, the coating layer contacts the printed plastic foil.

[0092] The top layer may comprise a printed plastic foil and on top of it a transparent or translucent plastic foil. Preferably, the transparent foil or the translucent foil is less than 150 pm thick. The coating layer is preferably provided on - and preferably contacting - the transparent or translucent plastic foil.

[0093] The coating layer will act as wear layer to the decorative panel. The function of the transparent or translucent plastic foil is not improving wear resistance as in the case of traditional polyvinyl chloride floor panels such as LVT or SPC floor panels; but only as carrier for the coating layer. The coating layer could be applied on a printed plastic foil. However, it is favorable to apply the coating layer on a transparent or translucent plastic foil (preferably a rather thin transparent or translucent plastic foil) rather than on the printed plastic foil. As the printed plastic foil is more expensive than a transparent or translucent plastic foil, wasted foil in the coating process is less expensive when coating on a transparent or translucent plastic foil.

[0094] The transparent or translucent foil, with the coating layer on it, can then be laminated on a printed plastic foil on a substrate, e.g. a polyvinyl chloride based board.

[0095] A preferred decorative panel according to the third aspect of the invention is characterized in that at least the coating layer is embossed. More preferably, the coating layer is embossed in register with the printed decor. This way, a realistic wood or stone imitation can be provided.

[0096] In preferred decorative panels, the coating layer preferably has a mass between 50 and 300 g / m2; more preferably of more than 100 g / m2; more preferably between 120 and 160 g / m2. Such coating layers enable deep embossing - optionally in register with a printed decor of the decorative panel - such that a realistic wood imitation can be provided. A preferred decorative panel according to the third aspect of the invention is characterized in that the substrate comprises or consists of a wood-based panel (e.g. a wood fiber board or a wood particle board), a mineral panel (e.g. an MgO based board) or a board comprising a plastic matrix (e.g a polyvinyl chloride matrix, a polypropylene matrix or a polyester matrix - e.g. a thermoset polyester matrix or a polyester terephthalate matrix). The plastic matrix can be filled, e.g. with lignocellulosic particles or with inorganic particles.

[0097] A preferred decorative panel is characterized in that the decorative panel is rectangular - square or oblong -, wherein the decorative panel comprises at least at two opposite side edges coupling parts for coupling the decorative panel with a second such decorative panel at their respective side edges; wherein in coupled condition a locking is provided in the direction perpendicular to the surface of the coupled decorative panels; as well as a locking is provided in the direction perpendicular to the coupled side edges and parallel to the surface of the coupled decorative panels; wherein the coupling parts comprise at one of said two opposite side edges a male coupling part; wherein the coupling parts comprise at the other one of said two opposite side edges a female coupling part.

[0098] It is a benefit of such embodiments that the decorative panels can be easily installed in a floating floor covering.

[0099] Preferably, the male coupling part comprises a tongue; and the female coupling part comprises a groove, wherein the groove is bordered by an upper lip and by a lower lip. More preferably, the lower lip extends more distal than the upper lip.

[0100] The coupling parts are preferably configured as on the one hand a tongue and on the other hand a groove bordered by an upper lip and a lower lip. The tongue and the groove provide in coupled condition a locking in the direction perpendicular to the surface of the coupled decorative panels. The tongue and the female coupling part comprise locking parts, wherein the locking parts provide in coupled condition a locking in the direction perpendicular to the coupled side edges and parallel to the surface of the coupled decorative panels. The locking parts can comprise a protrusion at the lower lip and a corresponding recess at the bottom of the tongue.

[0101] The coupling parts are preferably configured such that coupling can be performed by means of an angling movement of the respective side edges of the decorative panels to be coupled.

[0102] The fourth aspect of the invention relates to a method for obtaining a coated substrate, wherein the method comprises the steps of

[0103] - applying a coating composition as in any embodiment of the first aspect of the invention on a carrier substrate, thereby obtaining a coating layer on the carrier substrate;

[0104] - partially photocuring the coating layer to a non-tacky pre-gelled state.

[0105] The coating substrate can be used in the production of a decorative panel, e.g. by laminating the coating substrate of the fourth aspect of the invention to a board, and thermally curing the coating layer in a thermal press operation wherein in the same operation the coating layer is provided with a texture by copying the texture of a structured press element or a structured foil put between the press element and the coating layer. This way, a decorative panel with an appealing visual can be obtained.

[0106] A preferred embodiment of the fourth aspect of the invention is characterized in that between 50 and 300 gram (and preferably more than 100 gram) of the coating composition is applied per square meter of the carrier substrate.

[0107] Such coating layers result in excellent abrasion and wear resistance of the fully cured coating layer; and can be deeply embossed e.g. for imitating the texture of a wood panel.

[0108] The carrier substrate can e.g. be selected from a printed - and preferably resin impregnated - paper sheet, a printed plastic foil, an unprinted transparent paper sheet, a translucent paper sheet or a veneer. A preferred method of the fourth aspect of the invention is characterized in that the method comprises the step of performing a thermal pressing operation onto the coating layer thereby thermally curing the coating layer.

[0109] The thermal pressing operation can be performed on a stack comprising the carrier substrate with the partially photocured coating layer. The stack can comprise a board. Preferably, the layers of the stack are laminated to each other in the thermal pressing operation.

[0110] An embodiment of the method of the fourth aspect of the invention is characterized in that in the thermal pressing operation a texture is pressed at least into the coating layer.

[0111] The texture can be provided in register with a printed decor of the coated substrate.

[0112] The fifth aspect of the invention relates to a coated carrier substrate, characterized in that the coated carrier substrate comprises a carrier substrate and a coating layer. The coating layer is a partially cured coating layer obtained from a coating composition as in any embodiment of the first aspect of the invention. The partially cured coating layer comprises one or more thermo initiators.

[0113] The one or more thermo initiators preferably were present in the coating composition before its partial curing. The partial curing can have been done by means of radiation curing, which is not affecting the thermo initiators. A thermal curing operation - e.g. a thermal pressing operation - can be performed to cure the coating layer thermally.

[0114] A preferred coated carrier substrate of the fifth aspect of the invention is characterized in that the surface of the partially cured coating layer is non-tacky.

[0115] Such coated carrier substrates can be stacked and stored for use later on.

[0116] A preferred coated carrier substrate of the fifth aspect of the invention is characterized in that the carrier substrate is selected from a printed - and preferably resin impregnated - paper sheet, a printed plastic foil, an unprinted transparent paper sheet, a translucent paper sheet or a veneer.

[0117] A preferred coated carrier substrate of the fifth aspect of the invention is characterized in that the coating layer has a weight between 50 and 300 (and more preferably more than 100) gram per square meter of the carrier substrate.

[0118] Such coating layers will after final curing provide excellent wear resistance, e.g. for use in floor panels.

[0119] A preferred coated carrier substrate of the fifth aspect of the invention is characterized in that the partially cured coating layer has been partially cured using UV-radiation or electron beam radiation, preferably in combination with excimer radiation or LED- radiation.

[0120] It has been noticed that partial curing including excimer radiation or LED-radiation can result in a substantially fully cured thin top layer of the coating layer, and an only partially cured body of the coating layer. This coating layer is non-tacky. In a thermal pressing operation, the coating layer can substantially copy the surface texture of a structured press element and the coating layer is thermally cured initiated by the presence of the thermo initiators in the coating layer. It is believed that in the thermal pressing operation, the thin fully cured top layer is broken, the volume of partially cured coating composition will flow to create the texture and the small broken fragments of the thin fully cured top layer of the partially cured coating layer are incorporated as fragments in the thermally cured coating layer.

[0121] The sixth aspect of the invention relates to a method for obtaining a coated substrate, wherein the method comprises the steps of providing a coated carrier substrate as in any embodiment of the fifth aspect of the invention; and performing a thermal pressing operation onto the coated carrier substrate thereby thermally curing the coating layer. A preferred method for obtaining a coated substrate is characterized in that the method comprises the steps of providing a board; and obtaining a stack by at least applying the coated carrier substrate on the board. The step of performing a thermal pressing operation onto the coated carrier substrate is performed on the stack. In the thermal pressing operation the coated carrier substrate is laminated onto the board.

[0122] The board can comprise or consist of a wood-based panel (e.g. a wood fiber board or a wood particle board), a mineral panel (e.g. an MgO based board) or a board comprising a plastic matrix. Examples of a plastic matrix that can be used in the invention are polyvinyl chloride (PVC), polypropylene (PP) or polyester (PES), e.g. polyester terephthalate (PET).

[0123] The board can comprise a plastic matrix. The stack can comprise the board, a printed plastic foil, and the coated carrier substrate. The carrier substrate of the coated carrier substrate can be a transparent or translucent plastic foil, preferably less than 150 pm thick.

[0124] The plastic matrix can be polyvinyl chloride (PVC), polypropylene (PP) or polyester (PES), e.g. polyester terephthalate (PET). The plastic matrix can be filled, e.g. with organic or inorganic particles.

[0125] A preferred embodiment is characterized in that in the thermal pressing operation a texture is pressed at least into the coating layer.

[0126] The coating layer had been previously partially cured to non-tacky condition. It has been observed that in thermal pressing with a structured press element, the coating composition can sufficiently flow - after breaking a fully cured very thin top layer of the coating - such that a texture is pressed in the coating composition and that in the same thermal pressing operation, the coating is thermally cured in which the thermo initiators initiate the curing. The texture can be provided by copying the texture of a structured press element, or by introducing a texture foil in the press used for the thermal pressing operation.

[0127] The texture can be provided in register with a printed decor of the coated substrate.

[0128] When UV-radiation is mentioned, unless otherwise specified, the UV-radiation can be generated by means of one or more UV-radiation lamps, or by means of LEDs (Light Emission Diode) emitting UV-radiation. The use of LEDs emitting UV-radiation is favored because they are as a product more environmentally friendly and generate a more narrow wavelength range of UV-radiation compared to UV-radiation lamps.

[0129] 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 illustrates a method according to aspects of the invention for curing an acrylate coating composition according to the invention to partially cured non- tacky state; figure 2 shows a method according to aspects of the invention for manufacturing a decorative panel according to the invention; figure 3 shows a decorative panel according to aspects of the invention; and figure 4 shows a floor panel derived from the decorative panel of figure 3.

[0130] Figure 1 illustrates an example of a method according to aspects of the invention for curing a coating composition to partially cured non-tacky state.

[0131] An acrylate coating composition 22 is applied using a suitable coating applicator 20 on a printed paper sheet 10 impregnated with a thermoset resin cured to B-stage (which means partially cured). The coating composition 22 is applied in an amount of 200 g / m2of the printed paper sheet 10. The coating composition comprises:

[0132] (A) one or more oligomers selected from the group consisting of polyester acrylates and polyester methacrylates, or mixtures thereof; (B) one or more acrylate reactive diluents having a molar mass lower than 800 g / mol;

[0133] (C) one or more photo initiators; and

[0134] (D) a first thermo initiator, a second thermo initiator, a third thermo initiator and a fourth thermo initiator.

[0135] The acrylate coating composition 22 can be a coating composition as in any embodiment of the first aspect of the invention.

[0136] The first thermo initiator has a 60 seconds half-life of 130°C. The second thermo initiator has a 60 seconds half-life temperature of 150°C. The third thermo initiator has a 60 seconds half-life temperature of 165°C. The fourth thermo initiator has a 60 seconds half- life temperature of 177°C.

[0137] A first UV-radiation step 26, 28 is applied to printed paper sheet 20 carrying the acrylate coating composition. In this first UV-radiation step, the printed paper sheet 20 with the acrylate coating composition 22 applied on it consecutively passes two UV-lamps 26, 28.

[0138] A second UV-radiation is performed step by passing the printed paper sheet 20 with the acrylate coating composition 22 on it under an excimer-type monochromatic radiation lamp 30. In the example shown, the excimer-type monochromatic radiation lamp is a Xe2 excimer lamp emitting UV-radiation at 172 nm wavelength. In an alternative embodiment, a LED bulb can be used instead of the excimer-type monochromatic radiation lamp.

[0139] A third UV-radiation step 32, 34 is applied to the printed paper sheet 20 with the coating composition. In this third UV-radiation step, the printed paper sheet 20 with the acrylate coating composition 22 applied on it consecutively passes two UV-lamps 32, 34.

[0140] Obtained is a resin impregnated printed paper sheet (sheet 40) comprising an acrylate coating layer which is partially cured to partially cured state. The surface of the acrylate coating layer is not tacky. In the example shown, the first UV-radiation step 26, 28; the second UV-radiation step 30; and the third UV-radiation step 32, 34 are performed in-line and continuously.

[0141] As an alternative to the printed paper sheet 10, the acrylate coating composition can e.g. be applied on a plastic film or on a board having a printed decor.

[0142] Figure 2 shows an example of a method according to aspects of the invention for manufacturing a decorative panel according to aspect of the invention. The method comprises the step of providing a substrate, e.g. a board 42, which can e.g. be a woodbased board, a wood fiber board, a wood chip board, a mineral board - e.g. a magnesium oxide based board -, a - whether or not filled - plastic board, preferably a - whether or not filled - thermoplastic board.

[0143] A sheet 40 as obtained in the method shown in figure 1 is placed on the board 42. The sheet 40 is a printed paper sheet impregnated with a thermoset resin comprising an acrylate coating layer from an acrylate coating composition as in the first aspect of the invention. The acrylate coating layer is partially cured and wherein the surface of the coating layer is not tacky.

[0144] A second paper sheet 44 impregnated with a thermoset resin can be positioned at the other side of the board 42.

[0145] The stack of the sheet 40, the board 42 and the second paper sheet 44 is pressed at elevated temperature in a single daylight press 50. The press element of the singe daylight press 50 is in the example shown a structured press element 52. In the single daylight press 50, the printed paper sheet 40 and the second paper sheet 44 are laminated to the board 40 thanks to the partially cured resins with which the printed paper sheet 40 and the second paper sheet 44 are impregnated. In the single daylight press, the acrylate coating layer of the printed paper sheet 40 is embossed in which the texture of the structured press element 50 is copied and the acrylate coating layer is thermally cured. Using an appropriate structured press element 52 and correct positioning of the printed paper sheet 40, an embossment in register with the printed design of the printed paper sheet 40 can be obtained. The press element can also provide a pressed bevel to the decorative panel.

[0146] The second paper sheet 44 can provide a balancing layer to the decorative panel which is obtained in the described thermal pressing operation.

[0147] With the method of figure 2, a decorative panel 60 as shown in figure 3 can be obtained. The decorative panel comprises a board 42, a resin impregnated printed paper sheet 46 having an acrylate coating layer obtained from an acrylate coating composition according to the first aspect of the invention. The decorative panel is embossed with a texture in register with the printed decor of the printed paper sheet. The bottom of the decorative panel 60 shown in the example comprises an impregnated second paper sheet 44 acting as balancing layer.

[0148] The rectangular and oblong decorative panel 60 of the example of figure 3 has been processed into the floor panel of figure 4 (the reference numerals of figure 4 have the same meaning as in figure 3). To this end, the panel has been provided at two opposite side edges 70, 71 with coupling parts for coupling the decorative panel with a second such decorative panel at their respective side edges. In coupled condition a locking is provided in the direction perpendicular to the surface of the coupled decorative panels; as well as a locking is provided in the direction perpendicular to the coupled side edges and parallel to the surface of the coupled decorative panels. The coupling parts comprise at one of the two opposite side edges 70 a male coupling part comprising a tongue 72. The coupling parts comprise at the other one of said two opposite side edges 71 a female coupling part comprising a groove 74. The groove 74 is bordered by an upper lip 75 and by a lower lip 76. The lower lip 76 extends more distal than the upper lip 75. The tongue 72 and the groove 74 provide in coupled condition a locking in the direction perpendicular to the surface of the coupled decorative panels.

[0149] The tongue 72 and the female locking part comprise locking parts 77, 78. The locking parts 77, 78 provide in coupled condition a locking in the direction perpendicular to the coupled side edges and parallel to the surface of the coupled decorative panels. In the example shown, the locking parts comprise a protrusion 77 at the lower lip 76; and a corresponding recess 78 at the bottom of the tongue 72.

[0150] In the example shown, the coupling parts are configured such that the coupling can be performed by means of an angling movement of the respective side edges 70, 71 of the decorative panels to be coupled.

[0151] An example of an acrylate coating composition according to the first aspect of the invention comprises:

[0152] 14.4 parts by weight of a trifunctional epoxy acrylate oligomer,

[0153] 25 parts by weight of a saturated polyester acrylate oligomer having acrylate functionality equal to three,

[0154] 25 parts by weight of an unsaturated polyester acrylate oligomer having acrylate functionality equal to three,

[0155] 30 parts by weight of an acrylate reactive diluents having three acrylate functionalities,

[0156] 0.1 parts by weight of Omnirad 2100, which is a blend of Norrish type I photo initiators,

[0157] 0.2 parts by weight of Luperox 531M60 (Arkema) which is a 60% solution of l,l-di(tert-amylperoxy)-cyclohexane peroxide in isododecane. l,l-di(tert- amylperoxy)-cyclohexane peroxide is a thermo initiator having a 60 seconds halflife temperature of 152 °C.

[0158] 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.

[0159] 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.

[0160] 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. Acrylate coating layers with acrylate coating compositions according to the invention have been applied on a melamine and acrylate resin impregnated printed paper sheet using 200 g / m2of this acrylate coating composition. The impregnated printed paper sheet can optionally comprise a primer that ensures proper adhesion between the impregnation resin and the acrylate coating layer applied on the printed paper sheet. This primer might be applied as a water-based polyurethane dispersion and / or a water-based polyurethane dispersion containing acrylate functionalities and / or a melamine primer; and / or mixtures thereof.

[0161] The acrylate coating layer has been partially cured (pre- gelled) to partially cured non- tacky state using a first UV-radiation step, a second UV-radiation step and a third UV- radiation step. The three UV-radiation steps have been performed in line and continuously. A Hg, a Ga or a Fe doped UV-radiation lamp can be used in the first UV- radiation step. The second UV-radiation step has been performed under inert atmosphere by a Xe2 excimer lamp (emitting monochromatic radiation at 172 nm wavelength). As an alternative, a LED-radiation source can be used. The third UV-radiation step has been performed by passing the coated printed paper sheet consecutively under two Ga or two iron doped UV lamps or under mercury UV lamps. This partial curing (pre-gelling) process resulted in a partially cured acrylate coating layer being non-tacky.

[0162] A single day light press with structured press element has been used to laminate using pressure and increased temperature the coated resin impregnated printed sheet of paper onto a High Density Fiberboard (HDF) in which the resin of the resin of the resin impregnated printed sheet of paper was cured. In the same pressing operation at 210°C during 20 seconds, the texture of the structured press element was copied into the acrylate coating layer and the acrylate coating layer was thermally cured. It has been observed that the texture of the structured press element was nicely copied at the surface of the laminate and that the acrylate coating layer was well cured.

[0163] In another example, 200 gram per square meter of the coating composition of the previous example has been applied on a transparent polyvinyl chloride film of 100 micrometer thick. The obtained coating layer has been partially cured (pre-gelled) in the same way as in the previous example. An SPC (Solid Plastic Composite) polyvinyl chloride substrate (which comprises a polyvinyl chloride matrix and mineral fillers) was used as substrate, on top of which a 80 micrometer polyvinyl chloride film provided with a printed decor has been stacked, and on top of which the transparent polyvinyl chloride film with the partially cured coating composition was stacked. In a pressing operation at elevated temperature, the stack has been pressed in which the substrate, polyvinyl chloride film provided with the printed decor and the transparent polyvinyl chloride film with the partially cured coating are laminated to each other; and in which the surface of the decorative panel obtained has been provided with a surface texture by copying the structure of the structured press element that was used at least into the coating layer.

[0164] The present invention is in no way limited to the embodiments described as an example 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, wherein the coating composition comprises(A) one or more oligomers selected from the group consisting of polyester acrylates and polyester methacrylates, or mixtures thereof, preferably wherein said oligomers have a molar mass equal to or higher than 800 g / mol and lower than 7000 g / mol;(B) one or more acrylate reactive diluents having a molar mass lower than 800 g / mol, and preferably lower than 500 g / mol;(C) one or more photo initiators; and(D) one or more thermo initiators.2.- Acrylate coating composition as in claim 1, characterized in that the polyester acrylate oligomers comprise or consist of polyester acrylate oligomers having an acrylate functionality of at least 3 and / or in that the polyester methacrylate oligomers comprise or consist of polyester methacrylate oligomers having an methacrylate functionality of at least 3.3.- Acrylate coating composition as in any of the preceding claims, characterized in that the amount of oligomers (A) in the coating composition is higher than 20 wt% and preferably below 60 wt% of the total amount of the polyester (meth)acrylate oligomers (A) and the acrylate reactive diluents (B).4.- Acrylate coating composition as in any of the preceding claims, characterized in that the amount of the one or more acrylate reactive diluents (B) is more than 35 wt% - and preferably less than 60 wt% of the total amount of the polyester (meth)acrylate oligomers (A) and the acrylate reactive diluents (B).5.- Acrylate coating composition as in any of the preceding claims, characterized in that the total amount of the polyester (meth)acrylate oligomers (A) and the acrylate reactive diluents (B) in the acrylate coating composition is at least 25 wt%, preferably at least 35 wt%; more preferably at least 55 wt%, more preferably at least 65 wt%.6.- Acrylate coating composition as in any of the preceding claims, characterized in that the average acrylate functionality of the acrylate reactive diluents (B) is at least 2, preferably at least 2.5, more preferably at least 2.8.7.- Acrylate coating composition as in any of the preceding claims, characterized in that the coating composition comprises one or more methacrylate reactive diluents having a molar mass lower than 800 g / mol - and preferably lower than 500 g / mol - preferably wherein the average methacrylate functionality of the methacrylate reactive diluents is at least 2, and preferably at least 3.8.- Acrylate coating composition as in claim 7, characterized in that in the combination of polyester (meth)acrylate oligomers (A), the polyester acrylate reactive diluents and the polyester methacrylate reactive diluents (B); the polyester methacrylate reactive diluents amount for less than 5 wt%; and preferably less than 2 wt%.9.- Acrylate coating composition as in any of the preceding claims 1 - 6, characterized in that the coating composition does not comprise methacrylate reactive diluents.10.- Acrylate coating composition as in any of the preceding claims, characterized in that the coating composition comprises one or more urethane (meth) acrylate oligomers, wherein the amount of urethane (meth) acrylate oligomers is less than 10 wt%, preferably less than 5 wt%, more preferably less than 2 wt%, of the combination of the polyester (meth)acrylate oligomers (A) and the one or more acrylate reactive diluents (B).11.- Acrylate coating composition as in any of the preceding claims, characterized in that the polyester (meth)acrylate oligomers (A) comprise or consist of unsaturated polyester (meth)acrylate oligomers; preferably at least 20 wt% of the polyester (meth)acrylate oligomers (A) are unsaturated polyester (meth)acrylate oligomers; more preferably unsaturated polyester acrylate oligomers.12.- Acrylate coating composition as in any of the preceding claims, characterized in that the one or more oligomers selected from the group consisting of polyester acrylates and polyester methacrylates, or mixtures thereof (A) comprise saturated polyester (meth)acrylate oligomers as well as unsaturated polyester (meth)acrylate oligomers, preferably wherein the weight ratio of saturated polyester (meth)acrylate oligomers to the unsaturated polyester (meth)acrylate oligomers is between 0.2 and 2.5; and more preferably between 1.5 and 0.5; more preferably between 1.2 and 0.8.13.- Acrylate coating composition as in any of the preceding claims, characterized in that the one or more thermo initiators comprise 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.14.- Acrylate coating composition as in claim 13, characterized in that the one or more thermo initiators comprise 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.15.- Acrylate coating composition as in claim 14, characterized in that the one or more thermo initiators comprise 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.16.- Acrylate coating composition as in any of the preceding claims, characterized in that the one or more photo initiators are present in the acrylate coating composition in an amount less than 1 wt% of the combination of the weight of the one or more oligomers selected from the group consisting of polyester acrylates and polyester methacrylates (A) and the one or more (meth)acrylate reactive diluents (B), preferably less than 1 wt%, more preferably less than 0.1 wt%, more preferably less than 0.06 wt%, more preferably less than 0.04 wt%.17.- Acrylate coating composition as in any of the preceding claims, characterized in that the coating composition comprises one or more than one of a propoxylated acrylate monomer, a propoxylated acrylate oligomer, an ethoxylated acrylate monomer, an ethoxylated acrylate oligomer, or combinations thereof; preferably in a combined amount of between 30 and 60 wt% of the combination of the weight of the one or more oligomers selected from the group consisting of polyester acrylates and polyester methacrylates (A) and the one or more (meth)acrylate reactive diluents (B).18.- Acrylate coating composition as in any of the preceding claims, characterized in that the coating composition comprises one or more epoxy acrylate oligomers, preferably with acrylate functionality 2 or at least 2.19.- Acrylate coating composition as in claim 18, characterized in that the amount of the epoxy acrylate oligomers is less than 20 wt% of the combination of the one or more oligomers selected from the group consisting of polyester acrylates and polyester methacrylates (A) and the one or more (meth)acrylate reactive diluents (B).20.- Acrylate coating composition as in any of the preceding claims, characterized in that the coating composition comprises silica (SiCh), preferably in an amount more than 0.05 wt of the total coating composition, and preferably less than 1 wt% of the coating composition.21.- Acrylate coating composition as in any of the preceding claims, characterized in that the coating composition comprises AI2O3 particles, preferably in an amount more than 0.05 wt of the total coating composition, and preferably less than 7 wt% (and more preferably less than 2 wt%) of the coating composition.22.- Acrylate coating composition as in any of the preceding claims, characterized in that the coating composition comprises wear resistant particles, e.g. corundum or silicon carbide.23.- Acrylate coating composition as in any of the preceding claims, characterized in that the coating composition comprises inert beads, preferably inert acrylic beads or polyurethane beads or poly(methyl methacrylate) (PMMA) beads, preferably wherein the inert beads have a glass transition temperature (Tg) of at least 80°C, more preferably of at least 100 °C, even more preferably of at least 150 °C; preferably wherein the acrylate coating composition comprises between 5 and 35 wt% inert beads relative to the combination of the one or more oligomers selected from the group consisting of polyester acrylates and polyester methacrylates (A) and the one or more (meth)acrylate reactive diluents (B).24.- Acrylate coating composition as in any of the preceding claims, characterized in that the combination of the one or more photo initiators (C) and the one or more thermo initiators (D) relative to the total amount of the combination of the one or more oligomers selected from the group consisting of polyester acrylates and polyester methacrylates (A) and the one or more acrylate reactive diluents (B) is less than 1 wt%, preferably less than 0.5 wt%.25.- Acrylate coating composition as in any of the preceding claims 1 - 24, characterized in that it results after full curing in a transparent coating layer26.- Acrylate coating composition as in any of the preceding claims 1 - 24, characterized in that the acrylate coating composition comprises pigments or dyes, preferably in an amount of 0.5 - 10 wt% relative to the total weight of the acrylate coating composition.27.- Acrylate coating composition as in any of the preceding claims, characterized in that the acrylate coating composition comprises non-(meth)acrylate unsaturated polyester oligomers.28.- Acrylate coating composition as in any of the preceding claims, characterized in that the acrylate coating composition comprises a matting agent, preferably wherein thematting agent provides between 2 and 14 wt% - and more preferably between 3 and 10 wt% - of the acrylate coating composition.29.- Acrylate coating composition as in claim 28, characterized in that the matting agent is an amorphous silica, preferably having S50 particle size according to volume between 3 and 20 micrometer.30.- Coating layer, characterized in that the coating layer is obtained from a coating composition (22) as in any of the preceding claims 1 - 29, preferably wherein the coating layer has a mass between 50 and 300 g / m2, preferably more than 100 g / m2, more preferably between 120 to 160 g / m2.31.- Decorative panel, characterized in that the decorative panel (60) comprises a substrate (42), and a top layer (40); wherein the top layer comprises a printed decor and a coating layer, wherein the coating layer is a coating layer obtained from a coating composition as in any of the preceding claims 1 - 29, and / or a coating layer as in claim 30.32.- Decorative panel as in claim 31, characterized in hat the coating layer has a mass between 50 and 300 gram per square meter of the surface of the decorative panel.33.- Decorative panel as in any of the preceding claims 31 - 32, characterized in that the top layer comprises a resin impregnated paper sheet (10) comprising the printed decor, preferably wherein the coating layer contacts the resin impregnated paper sheet.34.- Decorative panel as in claim 33, characterized in that the impregnated printed paper sheet comprises a primer onto which the coating layer is applied; preferably wherein the primer comprises resins selected from the list of polyurethane, polyurethane with acrylate functionalities, melamine formaldehyde resin; or combinations thereof.35.- Decorative panel as in any of the preceding claims 31 - 34, characterized in that the top layer (40) comprises a printed plastic foil, preferably wherein the coating layer contacts the printed plastic foil.36.- Decorative panel as in any of the preceding claims 31 - 35, characterized in that the top layer comprises a printed plastic foil and on top of it a transparent or translucent plastic foil - preferably less than 150 pm thick -, preferably wherein the coating layer is provided on - and preferably contacting - the transparent or translucent plastic foil.37.- Decorative panel as in any of the preceding claims 31 - 36, characterized in that at least the coating layer is embossed, preferably in register with the printed decor.38.- Decorative panel as in any of the preceding claims 31 - 37, characterized in that the substrate (42) comprises or consists of a wood-based panel (e.g. a wood fiber board or a wood particle board), a mineral panel (e.g. an MgO based board) or a board comprising a plastic matrix (PVC, PP, PES. . .).39.- Decorative panel as in any of the preceding claims 31 - 38, characterized in that the decorative panel (60) is rectangular - square or oblong -, wherein the decorative panel comprises at least at two opposite side edges (70, 71) coupling parts for coupling the decorative panel with a second such decorative panel at their respective side edges; wherein in coupled condition a locking is provided in the direction perpendicular to the surface of the coupled decorative panels; as well as a locking is provided in the direction perpendicular to the coupled side edges and parallel to the surface of the coupled decorative panels; wherein the coupling parts comprise at one of said two opposite side edges a male coupling part; wherein the coupling parts comprise at the other one of said two opposite side edges a female coupling part.40.- Decorative panel as in claim 39, characterized in that the male coupling part comprises a tongue (72); and wherein the female coupling part comprises a groove (74), wherein the groove is bordered by an upper lip (75) and by a lower lip (76); preferably wherein the lower lip extends more distal than the upper lip.41.- Decorative panel as in any of the preceding claims 39 - 40, characterized in that the coupling parts are configured as on the one hand a tongue (72) and on the other hand a groove (74) bordered by an upper lip (75) and a lower lip (76); wherein the tongue and the groove provide in coupled condition a locking in the direction perpendicular to the surface of the coupled decorative panels; wherein the tongue and the female coupling part comprise locking parts (77, 78), wherein the locking parts provide in coupled condition a locking in the direction perpendicular to the coupled side edges and parallel to the surface of the coupled decorative panels; preferably the locking parts comprise a protrusion (77) at the lower lip (76) and a corresponding recess (78) at the bottom of the tongue (72).42.- Decorative panel as in any of the preceding claims 39 - 41, characterized in that the coupling parts are configured such that said coupling can be performed by means of an angling movement of the respective side edges of the decorative panels to be coupled.43.- Method for obtaining a coated substrate, wherein the method comprises the steps of- applying a coating composition as in any of the preceding claims 1 - 29 on a carrier substrate, thereby obtaining a coating layer on the carrier substrate;- partially photocuring the coating layer to a non-tacky pre-gelled state.44.- Method as in claim 43, characterized in that between 50 and 300 gram of the coating composition is applied per square meter of the carrier substrate.45.- Method as in any of the preceding claims 43 - 44, characterized in that the carrier substrate is selected from a printed - and preferably resin impregnated - paper sheet, a printed plastic foil, an unprinted transparent paper sheet, a translucent paper sheet or a veneer.46.- Method as in any of the preceding claims 43 - 45, characterized in that the method comprises the step of performing a thermal pressing operation onto the coating layer thereby thermally curing the coating layer.47.- Method as in claim 46, characterized in that the thermal pressing operation is performed on a stack comprising the carrier substrate with the partially photocured coating layer - preferably wherein the stack comprises a board -, wherein in the thermal pressing operation, the layers of the stack are laminated to each other.48.- Method as in any of the preceding claims 46 - 47, characterized in that in the thermal pressing operation a texture is pressed at least into the coating layer.49.- Method as in claim 48, characterized in that the texture is provided in register with a printed decor of the coated substrate.50.- Coated carrier substrate, characterized in that the coated carrier substrate comprises a carrier substrate and a coating layer, wherein the coating layer is a partially cured coating layer obtained from a coating composition as in any of the preceding claims 1 - 29; wherein the partially cured coating layer comprises one or more thermo initiators.51.- Coated carrier substrate as in claim 50, characterized in that the surface of the partially cured coating layer is non-tacky.52.- Coated carrier substrate as in any of the preceding claims 50 - 51, characterized in that the carrier substrate is selected from a printed - and preferably resin impregnated - paper sheet, a printed plastic foil, an unprinted transparent paper sheet, a translucent paper sheet, or a veneer.53.- Coated carrier substrate as in any of the preceding claims 50 - 52, characterized in that the coating layer has a weight between 50 and 300 gram per square meter of the carrier substrate.54.- Coated carrier as in any of the preceding claims 50 - 53, characterized in that the partially cured coating layer has been partially cured using UV-radiation or electron beam radiation, preferably in combination with excimer radiation or LED-radiation.55.- Method for obtaining a coated substrate, wherein the method comprises the steps of- providing a coated carrier substrate as in any of the preceding claims 50 - 54,- performing a thermal pressing operation onto the coated carrier substrate thereby thermally curing the coating layer.56.- Method as in claim 55, characterized in that the method comprises the steps of - providing a board; and- obtaining a stack by at least applying the coated carrier substrate on the board; wherein the step of performing a thermal pressing operation onto the coated carrier substrate is performed on the stack; wherein in the thermal pressing operation the coated carrier substrate is laminated onto the board.57.- Method as in claim 56, characterized in that the board comprises or consists of a wood-based panel (e.g. a wood fiber board or a wood particle board), a mineral panel (e.g. an MgO based board) or a board comprising a plastic matrix (PVC, PP, PES. . .).58.- Method as in claim 56, characterized in that the board comprises a plastic matrix (e.g. a whether or not filled PVC, or PP, or polyester matrix), and wherein the stack comprises the board, a printed plastic foil, and the coated carrier substrate; wherein the carrier substrate of the coated carrier substrate is a transparent or translucent plastic foil, preferably less than 150 pm thick.59.- Method as in any of the preceding claims 55 - 58, characterized in that in the thermal pressing operation a texture is pressed at least into the coating layer.60.- Method as in claim 59, characterized in that the texture is provided in register with a printed decor of the coated substrate.

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