Paintable and painted materials with textured surfaces

Description

[0001] The invention relates to materials with structured surfaces made of amino group-containing plastics, which are particularly suitable for subsequent painting, structured surfaces made of amino group-containing plastics that have been painted, processes for their production, and the use of vinyl functionalization in the painting of structured surfaces made of amino group-containing plastics. BACKGROUND OF THE INVENTION

[0002] When using materials in furniture construction or for cladding floors, walls, or ceilings, it is often desirable to design their surfaces so that they not only resemble the look but also the feel of natural materials such as wood, ceramic, or stone. For this purpose, it is known in the art to create appropriately structured decors on material panels.

[0003] The production of flooring laminate, for example, is generally carried out as follows: First, an impregnated decorative paper (so-called impregnate) is created by printing the desired decor (wood grain, ceramic, mosaic, tile, etc.) onto a paper web, which is then impregnated with aminoplast resin. The resulting impregnate can be wound onto a roll or laid out in sheets and stored. In a second step, a carrier board (e.g. MDF, HDF, chipboard, or the like) is coated with the impregnate. To do this, the impregnate and, if necessary, other aminoplast resin-impregnated underlay and overlay papers are applied to the carrier board and then pressed onto the wood-based panel in a press under the influence of temperature. Under the influence of pressure and temperature, the resin melts, forming a homogeneous film layer and simultaneously bonding the paper to the wood-based panel.The upper pressing plate of the press can be provided as a matrix with a relief that advantageously matches the decor. During pressing, the corresponding impressions of the pressing plate create depressions in the aminoplast resin surface, simulating, for example, the surface of a wooden board, the roughness of a natural stone floor, or the joints of laid tiles or mosaic stones, in order to create the most realistic surface possible on the wood-based panel. The surface of the aminoplast resin layer replicates the negative structure of the pressing plates used.

[0004] Similarly, other material surfaces made of amino-containing plastics can also be structured during production. Aminoplast resins can also be applied in powder form and pressed onto carriers, or a carrier can be separately coated with an aminoplast resin or another amino-containing plastic. Materials that already consist of amino-containing plastics or contain them as a binding agent (such as the majority of chipboard and fiberboard) can also be provided with a structured surface. In addition to embossing using structured press plates, decorative structures can also be created through lamination, calendering, etching, lasering, or three-dimensional printing.

[0005] A disadvantage of the state of the art, however, has been the poor paintability of surfaces made of amino-group-containing plastics with decorative structures. Common radiation-curing paints adhere poorly to plastic surfaces containing amino groups. For this reason, primer coats or undercoats must be applied as adhesion promoters before the actual painting of the plastic surface with radiation-curing paints can take place. For melamine resin surfaces, which are particularly difficult to paint, special primer coats or hot-melt adhesives have been developed, which are applied directly to amino resin surfaces and can then serve as the basis for one or more additional paint coats. However, due to this mandatory multi-layer and thus thick paint structure, the underlying structure of the surface is lost during painting (see Fig. 5b ).

[0006] However, it would be desirable to be able to paint textured surfaces while retaining their original structure. This would allow the optical and decorative effects of textured surfaces discussed above to be combined with those of a paint finish. Especially with amino-containing plastics, and especially with aminoplast resin surfaces, overpainting would often be necessary to achieve the desired surface properties.

[0007] While amino-containing plastics in general, and aminoplast resins in particular, exhibit good hardness, chemical resistance, and heat and fire resistance, they also have disadvantages in terms of surface properties.

[0008] A particular disadvantage of aminoplast resin surfaces is their high gloss, which is perceived as distracting, especially when the goal is to imitate natural surfaces, as these usually have a much more matte appearance. Many consumers find a matte surface to be a calming factor for the eye, as opposed to an obtrusive high-gloss surface. Another advantage is that matte surfaces visually compensate for unevenness in the substrate more effectively than glossy surfaces. The high gloss also makes aminoplast resin surfaces very susceptible to organic soiling, such as food residue, grease, and especially fingerprints. Such soiling is easily noticeable on high-gloss plastic surfaces and affects the decorative effect or makes the surface appear dirty and unhygienic.

[0009] To adjust the gloss level and, in particular, to prevent fingerprints, aminoplast resin surfaces are partially coated with a lacquer. Specially developed anti-fingerprint coatings are also available for this purpose. But even apart from the anti-fingerprint effect, coating the aminoplast resin surface with a matt lacquer is often a good option for the reasons mentioned above. The wood and furniture industry is one of the largest users of dull-matt, matt, or semi-matt UV lacquers that have been specially developed for this sector. Synthetic silicas, for example, are used as matting agents. However, with UV lacquers, it is also possible to achieve matt effects physically, i.e., without the addition of matting agents. For example, so-called excimer UV curing can be used to create particularly microstructured and thus matt surfaces (see, for example, Jorge and Kiene. Wood coating.COLOR AND PAINT, 2019, pp. 132-133).

[0010] Plastic surfaces containing amino groups, and especially melamine surfaces, are sometimes perceived by consumers as artificial because they feel "cold." This, too, can be improved by structuring the surface or overcoating it.

[0011] A coating can also be used to advantageously adjust the mechanical and chemical surface properties. In particular, it is known that plastic surfaces containing amino groups have comparatively poor UV, weathering, and micro-scratch resistance. For this reason, aminoplast resin surfaces are often overcoated with more resistant UV coating systems. For example, UV topcoats with very high coating hardness and scratch resistance are known from the field of parquet coating. With aminoplast resin surfaces, it is particularly important to increase micro-scratch resistance.

[0012] EP 3 040 476 A1 describes a laminate for coating a panel-shaped wood-based material and a method for producing the laminate.

[0013] WO 2010 / 079014 A2 describes a construction element made of wood-based material with printed decoration and different degrees of gloss.

[0014] DE 10 2013 005 184 A1 describes a process for functionalizing a surface.

[0015] EP 3 210 772 A1 describes a melt-bonded decorative laminate.

[0016] EP 3 415 318 A1 describes a method and device for producing a decorative workpiece and workpiece.

[0017] Unfortunately, the state of the art has not yet made it possible to combine the optical and decorative advantages of structured material surfaces made of amino group-containing plastics with those of painting with radiation-curing paints in a simple and cost-effective manner. SUMMARY OF THE INVENTION

[0018] The object of the present invention was therefore to achieve structured paint surfaces on material substrates made of plastics containing amino groups in a simple and cost-effective manner.

[0019] This object is achieved according to the invention by the paintable material according to claim 1, the painted material according to claim 11, the processes for their production according to claims 19 and 20 and the use according to claim 21. Particular embodiments of the invention are set out in the dependent claims and are explained in more detail below, as is the general inventive concept.

[0020] The invention provides a paintable material having a surface made of a plastic containing amino groups, wherein the surface is structured and at least some of the amino groups on the structured surface of the plastic containing amino groups have been covalently functionalized with vinyl groups by grafting a functionalizing reagent, wherein the functionalizing reagent has at least one vinyl group and at least one group reactive towards the amino groups of the plastic containing amino groups, wherein the material can be painted with a vinyl-group-mediated radiation-curing paint.

[0021] According to a particularly preferred embodiment, the functionalizing reagent has a molecular weight of 90 to 2000, preferably of 95 to 1100 and particularly preferably of 95 to 600.

[0022] According to a particularly preferred embodiment, the further group in the functionalizing reagent which is reactive towards the amino groups of the amino group-containing plastic is selected from the group consisting of epoxides, anhydrides, acid chlorides, acid azides, sulfonyl chlorides, ketones, aldehydes, carboxylic acids, esters, in particular N-hydroxysuccinimide esters, imido esters, or carbonates, carbodiimides, isocyanates, isothiocyanates, alkyl halides, aryl halides, alkynes and vinyl groups such as acrylate, methacrylate or acrylamide.

[0023] According to a particularly preferred embodiment, the further group in the functionalization reagent which is reactive towards the amino groups of the amino group-containing plastic is also a vinyl group.

[0024] According to a particularly preferred embodiment, the structured surface of the amino group-containing plastic is functionalized by grafting by applying the functionalizing reagent in an amount of less than 5 g / m 2< , in particular less than 2 g / m 2< or less than 1 g / m 2< and by subsequent heating or irradiation with UV or electron beams.

[0025] According to a particularly preferred embodiment, the functionalizing reagent is selected from the group consisting of di-, tri-, tetra-, penta- or even higher functional acrylates, methacrylates, vinyl ethers and allyl ethers, wherein the functionalizing reagent can in particular be selected from the group consisting of trimethylolpropane triacrylate, dipropylene glycol diacrylate, tripropylene glycol diacrylate, hexanediol diacrylate, pentaerythritol tetraacrylate, dipentaerythritol pentaacrylate, dipentaerythritol hexaacrylate, neopentyl glycol diacrylate, as well as propoxylated or ethoxylated variants of these compounds, polyalkylene glycol diacrylates, in particular polyethylene glycol diacrylates, divinyl ethers, in particular diethylene glycol divinyl ether, triethylene glycol divinyl ether or cyclohexanedimethanol divinyl ether, and diallyl ether.

[0026] According to a particularly preferred embodiment, the vinyl groups in the material surface and / or in the functionalizing reagent are selected from the group consisting of acrylates, methacrylates, vinyl ethers, allyl ethers and vinyl aromatic compounds, the latter being able to be selected in particular from styrene, C 1-4 -alkyl-substituted styrene, stilbene, vinylbenzyldimethylamine, (4-vinylbenzyl)dimethylaminoethyl ether, N,N-dimethylaminoethylstyrene, tert-butoxystyrene and vinylpyridine.

[0027] According to a particularly preferred embodiment, the amino group-containing plastic is selected from the group consisting of aminoplast resins, aminopolysiloxanes, polyvinylamines, polyalkyleneimines, aminoepoxide resins and polyurethanes with terminal amino groups.

[0028] According to a particularly preferred embodiment, the amino group-containing plastic is an aminoplast resin, in particular a melamine-formaldehyde resin or a melamine-urea-formaldehyde resin.

[0029] According to a particularly preferred embodiment, the material is a sheet- or plate-shaped material, in particular a wood-based panel; a carrier coated with a plastic containing amino groups; an impregnated or coated paper or a laminate containing one or more impregnated or coated papers, in particular a DPL, HPL or CPL, a compact board or another laminate.

[0030] Furthermore, the invention provides a painted material with a structured paint surface, which is obtainable by: (a) providing a paintable material according to the invention, (b) applying a layer of a vinyl group-mediated radiation-curing paint to the vinyl group-modified, structured plastic surface of the material, (c) radiation curing the paint layer.

[0031] According to a particularly preferred embodiment, the radiation-curing lacquer is a topcoat and the lacquered material does not contain a lacquer primer or undercoat layer.

[0032] According to a particularly preferred embodiment, the total amount of radiation-curing lacquer applied to the plastic surface is less than 20 g / m 2< , in particular less than 15 g / m 2< or less than 10 g / m 2< .

[0033] According to a particularly preferred embodiment, the lacquer layer is an excimer-cured lacquer layer.

[0034] According to a particularly preferred embodiment, the lacquer layer is an excimer-cured lacquer layer and has a gloss value of less than 10, preferably less than 5, each measured according to EN ISO 2813 with the 60° geometry.

[0035] According to a particularly preferred embodiment, the lacquer layer is a matt lacquer and has a gloss value of less than 10, preferably less than 5, in each case measured according to EN ISO 2813 with the 60° geometry.

[0036] According to a particularly preferred embodiment, the structured material surface or the structured paint surface has an Rz value measured according to DIN EN ISO 4287 of at least 10 µm, in particular at least 15 µm or at least 20 µm.

[0037] According to a particularly preferred embodiment of the paintable material or the painted material, the surface structure of the structured material surface or the structured paint surface is a decorative structure originally produced by embossing, lamination, calendering, etching, lasering or printing, which in particular represents the surface structure of wood, natural stone, artificial stone, ceramics, metal, mosaics, floorboards, tiles, joints or another decorative structure visible to the naked eye.

[0038] Furthermore, the invention provides a process for producing a paintable material according to the invention, which comprises the following steps: a) Providing a material with a structured surface made of a plastic containing amino groups, wherein the material can be painted with a vinyl group-mediated radiation-curing paint, b) covalent functionalization of the structured surface with vinyl groups by (i) bringing the structured surface into contact with a functionalization reagent which has at least one vinyl group and at least one further group reactive towards the amino groups of the plastic containing amino groups and (ii) carrying out a chemical reaction to produce a covalent bond between the second reactive group of the functionalization reagent and an amino group on the structured surface of the plastic containing amino groups, whereby a structured surface covalently modified with vinyl groups is obtained.

[0039] Furthermore, the invention provides a method for producing a coated material according to the invention with a structured lacquer surface, which comprises the following steps: a) carrying out the process according to the invention for producing a paintable material or providing a paintable material according to the invention, b) applying a layer of a vinyl group-mediated radiation-curing paint to the vinyl group-functionalized, structured surface of the material, c) radiation curing the paint layer.

[0040] Furthermore, the invention provides a use of a vinyl functionalization as a replacement for a primer layer or undercoat in the painting of structured surfaces made of amino group-containing plastic with vinyl group-mediated radiation-curing paints.

[0041] The invention provides a material with a structured surface made of an amino-group-containing plastic, in which at least some of the amino groups on the structured surface of the amino-group-containing plastic have been covalently functionalized with vinyl groups by grafting a functionalizing reagent. This surface functionalization eliminates the need for a primer layer or undercoat. The structured surface according to the invention is directly paintable. For this reason, this first aspect of the invention is also referred to herein as a "paintable material."

[0042] The paintable material according to the invention can be produced by the process also provided by the invention, which comprises the following steps: a) Providing a material with a structured surface made of a plastic containing amino groups, b) covalently functionalizing the structured surface with vinyl groups by (i) bringing the structured surface into contact with a functionalizing reagent which has at least one vinyl group and at least one further group reactive towards the amino groups of the plastic containing amino groups and (ii) carrying out a chemical reaction to produce a covalent bond between the second reactive group of the functionalizing reagent and an amino group on the structured surface of the plastic containing amino groups, whereby a structured surface covalently modified with vinyl groups is obtained.

[0043] The advantage of the paintable material provided by the invention is that, by omitting a primer layer or undercoat, it can be coated with a correspondingly thinner layer of paint, thus preserving the original structure of the substrate after painting. For the first time, structured paint surfaces can be produced on plastics containing amino groups in a particularly simple and cost-effective manner.

[0044] Accordingly, the invention also provides a coated material with a structured lacquer surface, which can be obtained by coating the paintable material according to the invention. The process for producing the coated material according to the invention comprises the steps: (a) providing a paintable material according to the invention, (b) applying a layer of a radiation-curing paint to the vinyl-modified, structured plastic surface of the paintable material, and (c) radiation-curing the paint layer.

[0045] The invention therefore also encompasses, in particular, the use of vinyl functionalization as a replacement for a primer layer or undercoat when painting structured surfaces made of amino-group-containing plastic. This allows a significant reduction in the paint layer thickness to be achieved, making it possible for the first time to paint even structured substrates while retaining the surface structure. DETAILED DESCRIPTION OF THE INVENTION Plastic containing amino groups

[0046] When reference is made here to "amino-containing plastic," this refers to any plastic that has primary and / or secondary amino groups in its molecular structure. Plastic, in its usual sense, is to be understood as a polymer material. Unless otherwise specified, "plastic" or "resin" always means a solid, cured condensation product. According to a preferred embodiment, the amino-containing plastic has primary amino groups. These can be located, in particular, at the ends of the polymer molecule. According to another preferred embodiment, the amino-containing plastic has secondary amino groups. With these, the functionalization according to the invention surprisingly also works very well. In one embodiment, the functionalization takes place via the secondary amino groups of the amino-containing plastic. Amino-containing plastics are known to those skilled in the art.These can, for example, be selected from the group consisting of aminoplast resins, aminopolysiloxanes, polyvinylamines, polyalkyleneimines, amine-modified epoxy resins and polyurethanes with terminal amino groups.

[0047] According to a particularly preferred embodiment, the amino-containing plastic is an aminoplast resin, in particular a melamine-formaldehyde resin. Aminoplast resins are very versatile plastics that are used in a wide variety of compositions and forms. In order to increase the surface resistance of layered materials, laminates and / or wood-based materials, it is known to coat their surface with a layer of aminoplast resin (in practice typically a melamine-formaldehyde resin), for example in the form of a so-called liquid overlay or impregnated overlay paper. Aminoplast resins are also usually used in practice as impregnating resins or binders for the underlying layers. For those skilled in the wood processing industry, aminoplast resins are known not only for impregnating, impregnating and / or coating surfaces, but also primarily as glues, e.g.for chipboard or fiberboard production. Here, too, surfaces made of amino-containing plastics occur. However, aminoplast resins can also be applied in powder form to carrier materials and pressed onto them. All of these applications of aminoplast resins, known to those skilled in the art, result in materials with surfaces made of an amino-containing plastic within the meaning of the invention.

[0048] Aminoplast resins or aminoplasts are described in "Ullmann's Encyclopedia of Industrial Chemistry," 4th edition, 1974, in the chapter "Aminoplasts" in Volume 7, or in "Wood Materials and Glues" by Dunky and Niemz, 1st edition, 2002, in Volume I, Part II, Chapter 1. The term aminoplasts generally refers to condensation products obtained by reacting a carbonyl compound, in practice usually formaldehyde, with a component containing amino, imino, or amide groups.

[0049] According to the invention, the most important representatives of aminoplast resins are melamine-formaldehyde resins. These include all aminoplast resins formed from at least melamine and formaldehyde, including, for example, melamine-urea-formaldehyde resins. The latter are aminoplast resins formed from at least melamine, urea, and formaldehyde. In addition to melamine and formaldehyde, melamine-formaldehyde resins can also contain other components, in particular other components containing carbonyl and amino, imino, or amide groups, as well as additives and / or solvents. Melamine-formaldehyde resins, which are also referred to by those skilled in the art simply as melamine resins or melamine surfaces, have established themselves as surfaces, particularly in furniture manufacturing and in materials for interior design. Here, there is a great demand for both structured and painted surfaces, as explained above.The problem of undesirable gloss levels and the associated artificial appearance and feel, as explained above, is particularly evident in the case of melamine-containing aminoplast resin surfaces.

[0050] Polyvinylamines are prepared via polymer-analogous reactions such as hydrolysis of poly-N-vinylamides, such as poly-N-vinylformamide or poly-N-vinylacetamide, or poly-N-vinylimides, such as poly-N-vinylsuccinimide, which are easily accessible by polymerization of the corresponding monomers, or by Hofmann degradation from polyacrylamide.

[0051] Polyalkyleneimines are polymers with an N-atom-containing backbone linked by alkylene groups, which may bear alkyl groups on the non-N atoms. The polyalkyleneimine preferably has primary amino functions at the ends and preferably both secondary and tertiary amino functions in the interior; optionally, it may also have only secondary amino functions in the interior, resulting in a linear rather than a branched-chain polymer. The ratio of primary to secondary amino groups in the polyalkyleneimine is preferably in the range from 1:0.5 to 1:1.5, in particular in the range from 1:0.7 to 1:1. The ratio of primary to tertiary amino groups in the polyalkyleneimine is preferably in the range from 1:0.2 to 1:1, in particular in the range from 1:0.5 to 1:0.8.

[0052] Aminoepoxy resins are obtained by reacting epoxy resins with polyamines as hardeners, whereby the reaction conditions are selected such that terminal amino groups remain in the resin after the reaction. Epoxy resins are synthetic resins that contain epoxy groups. They are curable resins (reaction resins) that can be reacted with a hardener and optionally other additives to form a thermosetting plastic. The epoxy resins are polyethers with usually two terminal epoxy groups. The curing agents are reactants and, together with the resin, form the macromolecular plastic. Aminoepoxy resins as used here represent such a macromolecular plastic, obtained by reacting epoxy resins with polyamines as hardeners. The reaction conditions are selected such that terminal amino groups remain in the resin after the reaction.

[0053] Polyurethanes with terminal amino groups can be obtained by reacting polyurethane with residual NCO groups in the polyurethane with diamines. material

[0054] The term "material" as used here encompasses any molded body that can be painted. This could be, for example, a furniture component or a component suitable for covering floors, walls, or ceilings. As explained at the beginning, it is often desirable to provide these surfaces with a texture so that they not only have the appearance but also the feel of natural materials such as wood, ceramic, or stone. For this purpose, it is known in the art to create appropriately textured decors on materials for furniture or components.

[0055] In a preferred embodiment, the material that can be painted or painted according to the invention is a wood-based panel; a carrier coated with a plastic containing amino groups; an impregnated or coated paper or a laminate containing one or more impregnated or coated papers, in particular a DPL, HPL or CPL, a compact board or another laminate.

[0056] The paintable or painted material according to the invention is preferably a sheet- or plate-shaped material. However, other geometries are also possible; in particular, the material can also be a more complex three-dimensional molded part. According to a preferred embodiment, the material, especially if it is sheet- or plate-shaped, is suitable for the production of furniture surfaces or for cladding floors, walls, or ceilings.

[0057] Sheet- or plate-shaped materials have the advantage of having a largely flat surface. This surface can be structured relatively easily and with high throughput, for example, by using structured press plates during production or by subsequent lamination, calendering with a structuring roller, etching, lasering, or three-dimensional printing. The functionalization reagent according to the invention and the subsequent coating can also be applied particularly evenly and evenly to sheet- or plate-shaped materials, for example, by rolling, spraying, squirting, flooding, dipping, pouring, doctoring, and / or brushing.

[0058] The sheet-shaped material can be rolled up on a roll or stored in sheets. The sheet-shaped material can in particular be an impregnated material or a laminate.

[0059] In a preferred embodiment, the material according to the invention is a paper impregnated and / or coated with a plastic containing amino groups (in particular an aminoplast resin). Those skilled in the art also refer to this as an "impregnated material." According to another preferred embodiment, the material according to the invention is a laminate comprising several papers impregnated and / or coated with a plastic containing amino groups (in particular an aminoplast resin), or a laminate comprising one or more such papers and a carrier material. Laminates of several impregnated and / or coated papers and, if appropriate, carriers are referred to as laminates. Both impregnated materials and laminates or laminates are widely used in the production of furniture surfaces or for covering floors, walls, or ceilings, in particular for the production of floor panels.

[0060] Laminate, as used here, refers to a product comprising at least two layers bonded to one another across a surface. These layers can be made of the same or different materials. Laminates according to the invention have a layered structure, with the top layer comprising a decorative paper impregnated with an aminoplast resin, an overlay paper, or a specially applied layer of aminoplast resin, for example in the form of a so-called liquid overlay. The aminoplast resin is preferably a melamine-formaldehyde resin. Overlay paper and liquid overlay layers serve to protect the surface from external influences such as wear and scratching.

[0061] The laminate is preferably obtained by pressing one or more layers of paper impregnated and / or coated with an amino-containing plastic (in particular an aminoplast resin) together with, if appropriate, further synthetic resin-impregnated papers and, if appropriate, a carrier plate under pressure and heat. The structured surface made of an amino-containing plastic, as provided according to the invention, is preferably achieved by introducing the structure into the surface made of an amino-containing plastic during the production of the laminate by embossing with a structured press plate or calendering with a structured roller.The surface made of amino group-containing plastic is preferably formed by a paper arranged on the surface of the laminate, impregnated and / or coated with an amino group-containing plastic (in particular aminoplast resin) or a layer of a liquid overlay made of amino group-containing plastic (in particular aminoplast resin).

[0062] If the material is a laminate, it can be designed as a "Direct Pressure Laminate" (DPL), "High Pressure Laminate" (HPL), or "Continuous Pressure Laminate" (CPL). DPLs are produced by pressing one or more layers of resin-impregnated paper onto a carrier plate under pressure and heat. HPLs are produced by pressing several layers of resin-impregnated paper together under pressure and heat in a single- or multi-opening press. This is therefore a special type of laminate. The HPL can then be glued, laminated, or pressed onto a carrier plate under pressure and heat. CPLs are produced by pressing several layers of resin-impregnated paper together under pressure and heat in a continuously operating press, usually a double-belt press.CPL is therefore also a special type of laminate. A special form of CPL involves the continuous pressing of one or more layers of synthetic resin-impregnated paper onto a carrier board. All of the technologies mentioned are used for the production of furniture surfaces or for the manufacture of components for covering floors, walls, or ceilings, particularly in laminate flooring production. Phenolic resins are often used as synthetic resins for impregnating the inner paper layers. However, at least on the surface of the laminates or layered materials, there is one or more papers impregnated with a plastic containing amino groups, in particular a melamine-formaldehyde resin, especially decorative paper and overlay paper. The latter is a transparent paper impregnated with melamine-formaldehyde resin, which serves as a protective layer and may contain additional anti-abrasive components.A decorative paper is a printed or dyed special paper that is impregnated with aminoplast resin and used for the decorative coating of wood materials.

[0063] The material according to the invention can be a compact board. This refers to a laminated pressboard produced similarly to HPL by pressing several layers of resin-impregnated paper together under pressure and heat. While HPL laminates primarily serve as a coating material and are applied to carrier materials, compact boards can be designed on both sides and are used without a carrier material. According to DIN, compact boards are abbreviated DKS (decorative plastic laminate). They typically consist of several paper or fabric layers, the core of which is impregnated with phenolic resin and the outer layers with melamine-formaldehyde resin, and are then bonded together under heat and pressure.

[0064] A wood-based panel can be a particleboard, oriented strand board, or fiberboard. These have in common that during their production, lignocellulose-containing particles (chips, strands, or fibers) are glued with a binding agent and then pressed into the wood-based material. OSB (oriented strand board or oriented structural board) is a coarse particle board made from long, slender chips ("strands"). Particleboard, oriented strand board, or fiberboard are mostly aminoplastically bonded wood-based panels.

[0065] In order to have a surface made of a plastic containing amino groups, the wood-based panel is either produced with an amino-group-containing plastic as a binder or subsequently coated with an amino-group-containing plastic or an impregnate or laminate containing a surface made of an amino-group-containing plastic. The amino-group-containing plastic is preferably an aminoplast resin, in particular a melamine-formaldehyde or melamine-urea-formaldehyde resin. According to a preferred embodiment, the material is a wood-based panel coated with an aminoplast resin-impregnated paper, which, after embossing during pressing to form the material panel, represents the structured aminoplast resin surface of the wood-based panel. This corresponds to the DPL embodiment described above.

[0066] The material according to the invention can also generally be a carrier coated with a plastic containing amino groups.

[0067] Whenever reference is made here or elsewhere to "carrier," "carrier material," or "carrier board," this can specifically refer to a wood-based panel, mineral material, metal, or plastic board. This particularly applies to the previously described DPL, HPL, and CPL versions. The terms "wood," "mineral," "metal," and "plastic" refer to the main component (by weight) of the carrier board. The carrier board itself can also be a laminate or laminated material.

[0068] When reference is made here or elsewhere to "coating" or "coating" with the amino-containing plastic, this refers to any form of coating. The amino-containing plastic can be applied in liquid form, for example in the form of its monomers or precondensates, and then cured. However, the amino-containing plastic can also be applied as a layer in powder form and subsequently bonded, melted, or cured. "Coating" or "coating" is generally understood here to mean both the application of a layer of amino-containing plastic and the pressing or lamination with one or more papers impregnated and / or coated with an amino-containing plastic (especially an aminoplast resin). Functionalization with vinyl groups

[0069] A key aspect of the invention is to make the structured surface of the material, consisting of a plastic containing amino groups, directly paintable by functionalizing it with vinyl groups. This eliminates the need for additional primer or undercoat layers. This has the advantage, for structured substrates, that the surface structuring is retained even after painting.

[0070] To achieve this, according to the invention, at least some of the amino groups on the structured surface of the amino-containing plastic are covalently functionalized with vinyl groups by grafting a functionalizing reagent. Grafting occurs by bringing the structured material surface, which has an amino-containing plastic, into contact with the functionalizing reagent and causing it to react. The amino-containing plastic is thus covalently functionalized with vinyl groups in the cured state and thus only on its surface.

[0071] The resulting paintable material according to the invention has vinyl groups on its surface that are covalently anchored in the amino-containing plastic present on its surface. This achieves particularly good adhesion for radiation-curing paints, which also cure radically via vinyl groups. In the painted material according to the invention (see below), the paint layer is thus covalently anchored in the amino-containing plastic present on the surface of the material. This leads to particularly good adhesion of the paint layer and eliminates the need for a primer or undercoat layer.

[0072] In the context of the present invention, the term "vinyl group" encompasses any functional group that has a terminal C=C double bond. Such a double bond is suitable for participating in the radiation-curing-initiated radical polymerization of a radiation-curing coating.

[0073] A functionalization reagent, as used here, means a molecule that can be grafted onto an amino group located on the structured surface of the amino-containing plastic. Since the functionalization reagent also has at least one vinyl group in addition to this grafting functionality, the structured surface of the amino-containing plastic is functionalized with vinyl groups by grafting the functionalization reagent. The functionalization reagent is thus at least a bifunctional molecule (see Fig. 3a and 3c). Its first functional group, A, is a vinyl group. The second functional or reactive group, B, is the functionalizing reagent, which is reactive towards the amino groups of the amino-containing plastic. The functionalizing reagent therefore has at least one vinyl group and at least one further group that is reactive towards the amino groups of the amino-containing plastic. The grafting of the functionalizing reagent involves the further functional group B reacting with an amino group on the surface of the amino-containing plastic to form a covalent bond. This results in vinyl groups being grafted onto amino groups located on the structured surface of the material. When amino groups are mentioned here, this particularly refers to terminal -NH2 groups present in the amino-containing plastic.

[0074] For grafting, the structured material surface, which has a plastic containing amino groups, is brought into contact with the functionalization reagent and reacted.

[0075] The first step in the covalent functionalization of the structured surface with vinyl groups thus consists in bringing the structured surface into contact with a functionalization reagent that contains at least one vinyl group and at least one additional group that is reactive toward the amino groups of the amino-containing plastic. Contacting is achieved by applying the functionalization reagent to the structured material surface, which contains an amino-containing plastic. Application can be carried out in a variety of ways. According to the invention, it has been shown that even selective functionalization of the surface with vinyl groups is sufficient to act as reactive bond anchors for the subsequently applied layer of radiation-curing lacquer, resulting in a significant improvement in adhesion.Preferably, however, the functionalizing reagent is applied evenly to the structured surface of the amino-containing plastic. The functionalizing reagent can be applied by rolling, spraying, squirting, impregnating, pouring, doctoring, and / or brushing.

[0076] The second step in the covalent functionalization of the structured surface with vinyl groups involves reacting the functionalization reagent with at least some of the primary and / or secondary amino groups present on the surface of the structured material. This step involves conducting a chemical reaction to create a covalent bond between the second reactive group of the functionalization reagent and an amino group on the structured surface of the amino-containing plastic, thereby obtaining a structured surface covalently modified with vinyl groups.

[0077] The reaction takes place under reaction conditions that enable a covalent bond between the additional reactive group B of the functionalization reagent and the terminal amino groups of the aminoplast resin. The reaction conditions depend on the chemistry of the additional reactive group B. In many cases, heating of the material surface will be necessary. This can be achieved using radiant heaters or ovens. After application of the functionalization reagent, the material surface is preferably heated to a surface temperature of 30 °C to 100 °C, preferably 50 °C to 80 °C, and particularly preferably 60 °C to 70 °C.

[0078] In other cases (such as the Aza-Michael addition explained in more detail below), irradiation of the surface with high-energy radiation is sufficient according to the invention. The radiation dose is preferably at least 100 mJ / cm², more preferably at least 150 mJ / cm². The latter doses are required for reflective surfaces (e.g., white surfaces). Good results have been achieved when the radiation dose was in a range from 100 to 1000, preferably from 150 to 600 mJ / cm². In practice, the high-energy radiation is usually UV or electron beams. According to the invention, UV radiation includes the wavelength ranges of UVB radiation (280-320 nm), UVA2 radiation (320-340 nm), and UVA1 radiation (340-400 nm).UVC radiation (200-280 nm), vacuum UV radiation (100-200 nm), special excimer radiation (172 nm), and extreme UV radiation (1-100 nm) are also collectively referred to as UV radiation. High-energy radiation is preferably radiation with a wavelength of 280 nm or less. UV-C radiation is particularly practical.

[0079] Depending on the type of grafting reaction, it may also be necessary to apply the functionalizing reagent together with the required catalysts, additives, or solvents, either in one composition or separately. The skilled person can easily verify whether the grafting reaction was successful by examining the adhesion of a coating layer to the material surface treated with the functionalizing reagent. Only if covalent functionalization with vinyl groups—and thus grafting of the functionalizing reagent—has occurred can excellent adhesion be achieved, even without the otherwise required coating primer or undercoat layer.

[0080] Depending on the degree of conversion and the amount of functionalization reagent applied, it may be advisable to at least partially remove excess non-covalently attached functionalization reagent from the surface after the reaction before it is coated with a lacquer layer. Removal can be achieved simply by washing with a suitable solvent or wiping the surface. However, practical testing of the invention has shown that this is not necessary in many cases. On the one hand, choosing the right application quantities and reaction conditions results in an almost complete reaction and, on the other hand, the functionalization reagents, due to the mandatory vinyl group, also polymerize into the lacquer layer during the radical polymerization of a radiation-curing lacquer and therefore do not interfere with the lacquer film formation.

[0081] Due to the diverse grafting chemistry available for amino group functionalization, the number of possibilities for the reactive group B and the associated reaction pathways is correspondingly large. The further group B of the functionalization reagent, which is reactive toward the amino groups of the amino-containing plastic, can in particular be selected from the group consisting of epoxides, acid anhydrides, acid chlorides, acid azides, sulfonyl chlorides, ketones, aldehydes, carboxylic acids, esters, in particular N-hydroxysuccinimide esters, imido esters, or carbonates, carbodiimides, isocyanates, isothiocyanates, alkyl halides, aryl halides, alkynes, and vinyl groups such as acrylate, methacrylate, or acrylamide. All of these functional groups are capable of reacting with amino groups under conditions well known to those skilled in the art.Most of these groups react with primary or secondary amines by acylation to form the acid amide or by alkylation to form the secondary (or tertiary) amine. The reaction mechanisms and conditions are known to those skilled in the art and can be found in relevant organic chemistry textbooks or relevant journals.

[0082] According to a particularly preferred embodiment, the group in the functionalizing reagent that is reactive toward the amino groups of the amino-containing plastic is a vinyl group. In this particularly preferred embodiment, the functionalizing reagent thus comprises at least two vinyl groups. The first serves to anchor the polymer in the amino-containing plastic; the second remains even after grafting and serves to subsequently anchor the radiation-curing lacquer to be applied. The first and second vinyl groups can be identical or different from one another; they are preferably identical. The functionalizing reagent is particularly preferably a mirror-symmetric molecule with at least two vinyl groups.

[0083] The research underlying this invention has shown that vinyl groups are ideal for grafting functionalization reagents onto structured plastic surfaces containing amino groups. Under the influence of high-energy radiation, the vinyl groups react in an aza-Michael addition with the amino groups on the solid material surface. The aza-Michael addition of a primary amino group on the material surface with an acrylate group in the functionalization reagent is schematically shown below:

[0084] The corresponding reaction also occurs, or rather, as the inventors have determined, especially with secondary amines in the amino-containing plastic. This was recognized in series of experiments, where no difference in functionalization was observed depending on the number or presence of primary amino groups in the amino-containing plastic. Secondary amino groups appear to be sufficient for the present invention.

[0085] Practical experiments have shown that, with functionalization reagents containing two vinyl groups, only one of the two reacts with amino groups in the material surface. The other thus remains present as a functionalization in the material surface, as desired. This likely has several reasons. First, it is a solid-phase or solid / liquid reaction, which means there is no mixing of the reactants. Therefore, it seems sterically unlikely that the second vinyl group in the functionalization reagent, which protrudes from the material surface after grafting, would "find" another amino group in the surface to complete another aza-Michael addition. However, the molecular size and spacer length of the functionalization reagent also appear to play a role, as explained in more detail below.At least in the case of plastics containing amino groups, which only have terminal amino groups, the density of amino groups on the material surface will not be sufficient for both vinyl groups of a functionalization reagent to react with it.

[0086] The aza-Michael reaction between a vinyl group of the functionalizing reagent and an amino group in the material surface has the advantage that the functionalizing reagent only needs to be applied to the material surface and then subjected to irradiation with high-energy radiation (such as UV light or electron beam). In the material surface, both primary and secondary amines can add to the C=C double bond of the vinyl group of the functionalizing reagent in an aza-Michael addition.

[0087] For the aza-Michael addition, it is important that the high-energy radiation actually penetrates to the initially forming complexes of vinyl and amino groups. Only in this way are the electron donor-acceptor or charge-transfer complexes necessary for the Michael addition formed and dissolved by addition to the alkylamine. Since the amino group is located directly in the material surface, the complexes also only form immediately at the material surface. The layer of applied functionalization reagent must not be too thick, otherwise the high-energy radiation will not penetrate to the material surface. Particularly good results have been achieved when the functionalization reagent is applied in an amount of no more than 3 g / m², preferably no more than 2 g / m², and particularly preferably no more than 0.5 g / m² or 1 g / m².

[0088] If the functionalization reagent is applied in a composition rather than in pure form, it must not contain any substances that absorb the high-energy radiation. In particular, it must not contain any photoinitiators or radical initiators, as is otherwise common in coatings, as these would not only absorb the high-energy radiation but also lead to radical polymerization of the vinyl-containing functionalization reagent, which is undesirable. Such polymerization and film formation would render the vinyl groups intended for functionalization unavailable, and it would also prevent the high-energy radiation from penetrating the material surface to trigger the desired aza-Michael reaction between the functionalization reagent and the material surface.

[0089] For the same reason, the prior art has not yet resulted in the functionalization of, for example, melamine resin surfaces with vinyl groups when these surfaces were coated with radiation-curing lacquers. Firstly, the radiation is intercepted by the relatively thick primer, undercoat, or lacquer layers themselves, and in particular by the radiation-absorbing molecules such as photoinitiators contained therein, and does not reach the material surface. Thus, radiation-induced aza-Michael additions do not occur on the material surface in the prior art. However, even if this were the case, during radiation curing, all vinyl groups contained in the primer, undercoat, or lacquer composition react completely in the radiation-induced radical polymerization within a few seconds. Thus, there is no functionalization of the material surface with vinyl groups.

[0090] In a preferred embodiment of the invention, the functionalizing reagent is applied to the structured surface of the amino-group-containing plastic in an amount of less than 5 g / m 2 , in particular less than 2 g / m 2 or less than 1 g / m 2 . This is particularly advantageous if the functionalizing reagent and the amino groups are reacted using high-energy radiation or if the additional group contained in the functionalizing reagent that is reactive towards the amino groups of the amino-group-containing plastic is a vinyl group. This is because, especially for radiation-induced aza-Michael addition at the material surface, it is essential that the high-energy radiation also reaches the surface.

[0091] However, even if the functionalization is not based on a radiation-induced aza-Michael addition, these application quantities have proven advantageous and sufficient. As explained at the beginning, the inventors recognized that the smallest possible layer thickness on the structured material surface is necessary to preserve its structure during subsequent coating. Against this background, the "layer" of functionalization reagent should also be as thin as possible. It is also not appropriate to even speak of a layer in this context, since the functionalization reagent reacts with the material surface and is subsequently no longer recognizable as a separate layer.

[0092] After applying the functionalization reagent to the structured surface of the amino-group-containing plastic, it is preferably irradiated with high-energy radiation as described above. Especially for functionalization via aza-Michael additions, this creates the preferred reaction conditions to ensure covalent bonding to the solid material surface. The type and intensity of the high-energy radiation should be selected so that the complexes formed on the material surface between the functionalization reagent and the amino groups are excited and react in aza-Michael reactions.

[0093] The vinyl groups in the functionalizing reagent or in the functionalized material surface can, in particular, be selected from the group consisting of acrylates, methacrylates, vinyl ethers, allyl ethers, and vinyl aromatic compounds. The latter include, for example, styrene, C 1-4 -alkyl-substituted styrene, stilbene, vinylbenzyldimethylamine, (4-vinylbenzyl)dimethylaminoethyl ether, N,N-dimethylaminoethylstyrene, tert-butoxystyrene, and vinylpyridine. The group in the functionalizing reagent that is reactive toward the amino groups of the amino-containing plastic is particularly preferably an α,β-unsaturated carbonyl compound, in particular α,β-unsaturated carboxylic acid esters or α,β-unsaturated carboxamides. Acrylic acid and / or methacrylic acid esters are particularly preferred.α,β-Unsaturated carbonyl compounds or compounds that are α,β-unsaturated with respect to another electron-withdrawing group are particularly well suited for aza-Michael additions. Preferably, the vinyl group is a vinyl group directly bonded to an electron-withdrawing group, such as a carbonyl group.

[0094] Particularly good results are achieved when the functionalization reagent is selected from the group consisting of di-, tri-, tetra-, penta-, or even higher-functional acrylates, methacrylates, vinyl ethers, and allyl ethers. The functionalization reagent can, in particular, be selected from the group consisting of trimethylolpropane triacrylate, dipropylene glycol diacrylate, tripropylene glycol diacrylate, hexanediol diacrylate, pentaerythritol tetraacrylate, dipentaerythritol pentaacrylate, dipentaerythritol hexaacrylate, neopentyl glycol diacrylate, as well as propoxylated or ethoxylated variants of these compounds, polyalkylene glycol diacrylates, especially polyethylene glycol diacrylates, divinyl ethers, especially diethylene glycol divinyl ether, triethylene glycol divinyl ether, or cyclohexanedimethanol divinyl ether, and diallyl ether. The molecular weights of some of these compounds are shown below: Table 1 substance relative Molmasse ( M r ) Diallyl ether 98,14 Diethylene glycol divinyl ether 158,20 Cyclohexanedimethanol divinyl ether 196,29 Triethylene glycol divinyl ether 202,25 Neopentyl glycol diacrylate 212,24 Hexanediol diacrylate 226,27 Dipropylene glycol diacrylate 242,27 Trimethylolpropane triacrylate 296,32 Tripropylene glycol diacrylate 300,35 Pentaerythritol tetraacrylate 352,34 Dipentaerythritol pentaacrylate 524,51 Polyethylene glycol diacrylate e.g. with a mean M r of 532 Dipentaerythritol hexaacrylate 578,60 Polyalkylene glycol diacrylates e.g. with an average M r of 360 to 2000

[0095] When we speak of molecular weight here, we mean the relative molecular weight (M r ), that is, the molecular mass normalized to one-twelfth of the mass of the carbon isotope 12< C. Relative molecular weight therefore has no unit of measurement.

[0096] According to the molecular weights given in the table above, the functionalizing reagent is preferably a small molecule with a molecular weight of 90 to 2000, preferably of 95 to 1100 and particularly preferably of 95 to 600. This ensures that the molecular part between the vinyl groups ("spacer" 10, see Fig. 3) is as small as possible. The use of functionalization reagents in this molecular size range ensures that the structures grafted onto the amino groups of the material surface also have a molecular weight in the range of 90 to a maximum of 2000, preferably from 95 to a maximum of 1100, and particularly preferably from 95 to a maximum of 600. This results in the grafted vinyl groups in the functionalized material surface being as close to the material surface as possible. This appears to result in better anchoring and adhesion of the subsequently applied layer of radiation-curing lacquer.

[0097] Furthermore, with shorter spacers, the probability that the functionalization reagent will fold back after grafting onto the amino-containing surface and also react with the second vinyl group is minimized. This would otherwise run counter to the intended vinyl functionalization of the surface. For the same reasons, the functionalization reagent according to the invention should not be a lacquer or a polymer. Painted material

[0098] The above-described vinyl functionalization of the amino-containing surface results in a paintable material whose structured surface is retained even after painting. The invention accordingly also provides painted materials characterized by having a structured paint surface. These painted materials are obtainable by a process comprising the steps (a) Providing a paintable material as described above, ie a material having a structured surface made of a plastic containing amino groups, in which at least some of the amino groups on the structured surface of the plastic containing amino groups have been covalently functionalized with vinyl groups by grafting a functionalizing reagent; (b) applying a layer of a radiation-curing paint to the vinyl-functionalized, structured surface of the material; (c) radiation-curing the paint layer.

[0099] To the extent that any processes for achieving macroscopically structured paint surfaces are available in the state of the art, they involve subsequent structuring of the paint surfaces. However, such processes have not been widely adopted due to insufficient practical suitability. For example, it has been proposed to apply a structuring film to the paint layer and then peel this film off again. On the one hand, it is very difficult to apply the structure in a way that precisely matches an existing decor in the substrate. On the other hand, it is also difficult to introduce deeper structures without damaging the paint layer or the layers underneath. To create deeper structures, as is necessary, for example, to imitate a wood texture, correspondingly thicker paint layers must be applied.This not only has cost disadvantages, but in practice also usually means several consecutive paint applications to achieve the required layer thicknesses.

[0100] Finally, subsequent surface structuring of a paint also leads to defects in the paint surface and its microstructure. This means that a subsequently structured paint surface differs significantly in appearance, both macroscopically and microscopically, from an intact paint surface structured according to the invention. In the structured paint surface according to the invention, the surface structure is derived from the structure already present in the substrate, which is merely coated. According to the invention, the macroscopic structuring is present directly after coating and does not need to be subsequently introduced into the paint.

[0101] When we talk about a "structured" surface or "structuring" here, we mean a macroscopic structuring. This means a structure present in the surface, visible to the naked eye, that has a height and depth profile. The structuring is three-dimensional. The structured surface thus has a topography that can be felt when running your hand over it and that the observer's eye perceives as a structure. "Structure," "structured surface," "surface structure," "topography," and "height and depth profile" are used synonymously here.

[0102] The surface structure of the structured material or paint surface according to the invention is, in particular, a decorative structure originally created by embossing, lamination, calendering, etching, lasering, or printing. The surface structure of the structured material or paint surface is preferably a decorative structure visible to the naked eye. In a preferred embodiment, the surface structure of the structured material or paint surface represents the surface structure of wood, natural stone, artificial stone, ceramic, metal, mosaics, floorboards, tiles, joints, or another decorative structure visible to the naked eye.

[0103] According to a particularly preferred embodiment, the paintable or painted material has a decor, in particular a decor to which the structuring of the material or paint surface is coordinated. If the decor is a wood decor, for example, the structuring can consist of a three-dimensional imitation of the woodcut topography, i.e., grooves along the depicted growth lines and depressions at depicted knotholes, etc. If the decor is a tiled floor or a mosaic, the structuring can support this decor with depressions corresponding to the depicted joints.

[0104] In order to be perceived as a macroscopic structure with the naked eye, it is necessary that the depressions and elevations in the surface structure or topography are sufficiently pronounced. The surface quality of materials is quantified according to DIN EN ISO 4287 using the so-called stylus method. The characteristic values ​​Rz, Rz Max and Rt measured here according to DIN EN ISO 4287 are calculated as described in Fig. 7 shown and are defined as follows: Rz: averaged difference between the highest and lowest profiles; Rz Max: highest measured point; Rt: total height of the profile (distance between the highest peak and the lowest valley of the profile over the entire evaluated length ln).

[0105] According to a preferred embodiment, the structured material surface or the structured paint surface has an Rz value, measured according to DIN EN ISO 4287, of at least 10 µm, more preferably at least 15 µm, and especially preferably at least 20 µm. This ensures that the structure is easily palpable and visible and also distinguishes the surface structure according to the invention from the microstructure of the surface, which may have optical effects but is not perceptible to the naked eye as a structure. The Rz value, measured according to DIN EN ISO 4287, is preferably at most 120 µm, more preferably at most 100 µm, and especially preferably at most 80 µm.

[0106] According to one embodiment, the total layer thickness (measured after radiation curing) of radiation-curing paint in the painted material is at most half, and preferably at most one-third, of the Rz value of the unpainted material surface. Preferably, the painted material contains no primer or undercoat layers. This ensures that the structure present in the substrate is also retained as a structured paint surface in the painted material.

[0107] A person skilled in the art distinguishes between macroscopic and microscopic structures (so-called microstructures) in surfaces. Macroscopic structures are perceptible to the naked eye as structures. These are the ones referred to when "structure" or "structuring" is mentioned in this description. In contrast, microstructures, as the name suggests, are only visible with a microscope. Particularly advantageous microstructures can be created in a paint surface, for example, by excimer curing. The invention allows, for example, macroscopically structured aminoplast resin surfaces to be combined with an excimer-cured paint layer.

[0108] Excimer curing is well known to those skilled in the art and is used extensively in practice to mat paint surfaces. The matting process is purely physical and requires no additional matting agents. Excimer curing is based on the following principle: In radiation-curing paints (e.g., acrylates), the 172 nm excimer lamp (e.g., Excirad 172) creates free radicals that trigger polymerization and crosslinking. The penetration depth of the 172 nm photons into the acrylates is between 0.1 and 0.5 nm, so that only a very thin surface layer is crosslinked. The shrinkage caused by polymerization leads to microstructures. A wrinkled skin floats on the liquid film, which is then completely cured with a second radiation source. A mercury UV lamp, an electron beam lamp, or a long-wave excimer lamp with 308 nm can be used for this purpose.To avoid ozone formation, the irradiation takes place in a nitrogen atmosphere.

[0109] The physical micro-folding created with the 172 nm excimer lamp allows radiation-curing coatings to easily achieve gloss values ​​of 1 to 10 without the addition of matting agents, measured, for example, according to EN ISO 2813 with a 60° geometry. The high-energy, short-wave 172 nm radiation not only leads to the radical polymerization of the acrylate groups, but also to additional cross-linking of the monomers. This significantly increases surface hardness. The inventors have also discovered that excimer curing leads to a beneficial anti-fingerprint effect on coating surfaces.

[0110] The structured lacquer surface provided according to the invention can be combined in a particularly advantageous manner with a microstructure, in particular a microstructure produced in the lacquer surface by excimer curing.

[0111] According to a preferred embodiment, the coated material is characterized in that the coating layer is an excimer-cured coating layer.

[0112] By using such an excimer curing or selecting a correspondingly matt lacquer, it is possible according to the invention to obtain structured lacquer surfaces which have a gloss value of less than 10, preferably less than 5, each measured according to ÖNORM EN ISO 2813 (version 2015-01-01) with the 60° geometry.

[0113] Common plastics containing amino groups, in particular aminoplast resins, are not amenable to excimer curing. However, decorative structures can be embossed particularly well into their surfaces during production, e.g., using appropriately structured rollers or press plates. The invention makes it possible to combine macroscopic surface structures, e.g., created by embossing, with excimer curing during the lacquering process. This leads to structured material surfaces that have an exceptionally natural matt finish and, when combined with appropriate decors and structures (e.g., flooring laminate as a wood flooring imitation), are no longer distinguishable from the material to be imitated (e.g., real wood parquet). By appropriate microstructuring of the lacquer surface or the use of an appropriate lacquer, the invention also allows for the first time macroscopic, e.g.,to provide surface structures created by embossing with anti-fingerprint properties.

[0114] This is made possible by the vinyl functionalization of the material surface, which according to the invention makes it possible to dispense with the primer coat, undercoat, or filler otherwise required when coating plastics containing amino groups, in particular aminoplast resins, with radiation-curing coatings. In the prior art, these coatings result in coating layer thicknesses of regularly more than 20 or 30 g / m². Any surface structuring present in the substrate, as is common, for example, in the imitation of wood textures and decors, is inevitably leveled out and thus destroyed by such a thick coating application. For this reason, the prior art has so far refrained from coating structured aminoplast resin surfaces, as is common in laminate or furniture panel production.

[0115] The coated material according to the invention is characterized in that the applied layer of radiation-curing paint or paints is so thin that any existing structure in the substrate is essentially retained. This is made possible by the fact that, due to the vinyl functionalization, corresponding primer or undercoat layers can be dispensed with. Thus, the coated material typically does not contain a paint primer or undercoat layer. Therefore, the radiation-curing paint applied to the vinyl-functionalized surface can also directly be a topcoat. This would otherwise only adhere to common amino-containing plastics, in particular aminoplast resins, if pre-coated with appropriately designed paint primers or undercoats.

[0116] According to a particularly advantageous embodiment, the total amount of radiation-curing paint applied to the plastic surface of the paintable material is less than 20 g / m 2< , in particular less than 15 g / m 2< or less than 10 g / m 2< . In the painted material according to the invention, the average layer thickness of the paint layer of radiation-curing paint located on the structured plastic surface is preferably from 0 to 50 µm, particularly preferably from 5 to 35 µm, and most preferably from 5 to 15 µm. The layer thickness is measured microscopically using cross-sections according to DIN EN ISO 1463 (August 2004). The small paint application quantities or layer thicknesses made possible according to the invention mean that the surface structuring present in the substrate (the paintable material) is also retained in the painted material in the form of a structured paint surface. Radiation-curing varnish

[0117] The vinyl groups incorporated into the surface of the paintable material make it ideally prepared for subsequent coating with a radiation-curing coating. Most radiation-curing coatings themselves cure via vinyl-group-mediated radical polymerization. Thus, the vinyl groups in the material surface represent covalent anchoring points for the radiation-curing coating, resulting in excellent adhesion of the coating to the material surface.

[0118] The radiation-curing coating can be applied to the vinyl-functionalized, structured surface of the paintable material by any coating application method known to those skilled in the art. Application can be carried out, in particular, by rolling, spraying, squirting, flow coating, dipping, pouring, knife coating, and / or brushing.

[0119] By selecting the right radiation-curing coating, the desired gloss level and surface properties can be flexibly and precisely adjusted. Partial matte / gloss effects or matte / gloss gradations tailored to the decorative image can also be achieved by selecting a suitable radiation-curing coating. The radiation-curing coating should preferably have a gloss value of less than 10, preferably less than 5, measured according to ÖNORM EN ISO 2813 (version 2015-01-01) with a 60° geometry after curing.

[0120] Radiation-curing coatings are known to those skilled in the art and are described, for example, here: Prieto and Keine, "Wood Coating," COLOR AND LACQUER, 2019, Chapter 3.1.6 - Radiation-curing coating systems. A "radiation-curing coating," as used here, is a coating containing film-forming agents with carbon-carbon double bonds that undergo radical polymerization under the influence of ultraviolet light (UV) or ionizing radiation (EBR). The carbon-carbon double bonds are preferably acrylic double bonds, i.e., those derived from acrylic or methacrylic acid or derivatives of these compounds. During UV curing, photoinitiators must be added to generate the initiator radicals necessary for polymerization. In addition to the film-forming agent, the radiation-curing coating typically contains reactive diluents and photoinitiators, as well as, if appropriate,further additives selected from the group consisting of pigments, fillers, matting agents, defoamers, silicone oils, as well as inhibitors or stabilizers.

[0121] According to one embodiment, the radiation-curing coating is a radiation-curing acrylate resin. Due to their property profile, in particular the simultaneous fulfillment of mechanical (e.g., hardness, abrasion resistance, scratch resistance, and / or wear resistance) and optical requirements, these are typically used in coating compositions used for surface finishing. Dipropylene glycol diacrylate (DPGDA) and / or poly(propylene glycol diacrylate) (PPGDA) are preferably used as the radiation-curing acrylate resin. Other radiation-curable acrylate resins usable according to the invention are marketed, for example, by BASF under the trademark "Laromer®". Reference to "acrylate" here always includes the corresponding methacrylate derivative.

[0122] Reactive thinners are defined by those skilled in the art as polymerizable, radiation-curing monomers that are added to the radiation-curing paint to reduce its viscosity. Unlike a conventional solvent, reactive thinners react in the radical polymerization process during radiation curing and are thus incorporated into the paint film as monomers. Particularly good results can be achieved using monomeric (meth)acrylic acid esters as reactive thinners, which are liquid at room temperature. Examples of such compounds are isobornyl acrylate, hydroxypropyl methacrylate, trimethylolpropane formal monoacrylate, tetrahydrofurfuryl acrylate, phenoxyethyl acrylate, trimethylolpropane triacrylate, dipropylene glycol diacrylate, tripropylene glycol diacrylate, hexanediol diacrylate, pentaerythritol tetraacrylate, dipentaerythritol pentaacrylate, lauryl acrylate, and propoxylated or ethoxylated variants of these reactive thinners.Urethane-based reactive diluents such as EBECRYL 1039 (Cytec) or other compounds that are liquid at room temperature and capable of reacting under radical polymerization conditions, such as vinyl ethers or allyl ethers, are also suitable. Preferred vinyl ethers are diethylene glycol divinyl ether, triethylene glycol divinyl ether, or cyclohexanedimethanol divinyl ether. The radiation-curable coating can contain reactive diluents in amounts of 1-70 wt.%.

[0123] The film former in the radiation-curable coating is preferably selected from unsaturated polyesters, epoxy acrylates, polyester acrylates, polyether acrylates, amino-modified polyether acrylates, and urethane acrylates. Unsaturated polyesters (UP) based on maleic acid are particularly suitable. These are often combined with styrene as a reactive diluent.

[0124] To be UV-curable, radiation-curable coatings must contain photoinitiators. A wavelength of 200 nm is required for the homolytic cleavage of the C=C double bond. Commercially available UV lamps emit only a very small amount in this wavelength range. Furthermore, this radiation range is absorbed by air, creating ozone. Photoinitiators are radical generators capable of absorbing the higher-emission, longer-wavelength range of the UV lamp. The resulting radicals then trigger the radical polymerization of the reactive components of the UV coating (film formers and, if applicable, reactive thinners). Photoinitiators can, for example, be selected from the group consisting of alpha-hydroxyketones, 1-hydroxycyclohexylphenyl ketone, benzophenone, thioxanthones, benzoin, benzoin ethers, benzil ketals, aminoalkylphenones, hydroxyalkylphenones, monoacylphosphine oxides and bisacylphosphine oxides and their derivatives.If the radiation-curable varnish contains pigments or other absorbing substances, these and the photoinitiator used must be selected and matched with respect to the absorbed wavelength ranges.

[0125] The invention is described in more detail below using exemplary embodiments with reference to the accompanying drawings. These examples serve merely to illustrate the invention and do not limit its scope.

[0126] In the Drawings shows Fig. 1: a material which can be painted or varnished according to the invention and which is plate-shaped and whose surface has a structure which simulates a wood grain, Fig. 2: cross-sections through various plate-shaped materials which can be painted according to the invention and which are intended to illustrate the structure of these materials and their surface layers, showing Fig. 2a a laminate, Fig. 2ba laminate and Fig. 2c a wood material, Fig. 3: a schematic detailed view of the material surface made of a plastic containing amino groups, showing how an amino group present there can react with the functionalization reagent according to the invention to lead to a vinyl functionalization of the material surface, Fig. 4: cross sections through various plate-shaped materials coated according to the invention, which are the materials from Fig. 2 whose surface was functionalized according to the invention and then coated with a radiation-curing lacquer, Fig. 5: Schematic representations of the structured material surface before and after coating and, if applicable, functionalization, showing Fig. 5a a structured material surface before any functionalization or painting, Fig. 5b a surface primed or undercoated according to the state of the art and then painted, Fig. 5c a paintable material surface functionalized with vinyl groups according to the invention and Fig. 5d one like in Fig. 5c Fig. 6: a schematic representation of the manufacturing process for the material that can be painted or is painted according to the invention. Fig. 7: an exemplary stylus profile to explain the roughness parameters R z and R t used here. List of reference symbols 1 material 1' Paintable material 1" Painted material 2 Surface made of a plastic containing amino groups 3 structuring 4 Top layer 5 carrier plate 6 Countermove 7 core 8 Functionalization reagent 9 Vinyl group 10 Spacer 11 Covalent bond 12 Layer of radiation-curing varnish 13 Primer or primer layer 14 First feed conveyor belt 15 Second feed conveyor belt 16 Third feed conveyor belt 17 Belt conveyor system 18 Melamine resin impregnated decorative paper 19 Melamine resin impregnated overlay paper 20 Press stack 21 Short-cycle press 22 Structured pressed sheet 23 Device for applying the functionalization reagent 24 First radiation source 25 High-energy radiation 26 Device for applying the radiation-curing varnish 27 Excimer radiation source 28 Excimer radiation 29 Second radiation source 30 Feeding conveyor belt

[0127] Fig. 1shows a plan view of a material 1 that can be painted or has been painted according to the invention. In both cases, the characteristic structuring 3 of the surface can be seen (structured surface made of a plastic containing amino groups or a structured painted surface), which in the embodiment shown simulates a wood grain. The material 1 is plate-shaped and can have a decoration (e.g., a wood decoration) that is consistent with the structuring 3. The material 1 has a surface made of a plastic 2 containing amino groups, into which the structuring 3 is incorporated.

[0128] Fig. 2 shows cross sections through three exemplary materials 1 which can be used according to the invention and which can look in plan view as in Fig. 1 shown. The Fig. 2aThe material 1 shown is a laminate comprising a carrier plate 5, an underlying counter-layer 6, and an overlying top layer 4. The counter-layer 6 is typically a paper impregnated with synthetic resin, which serves to equalize the tensions on the top and bottom sides. The carrier plate 5 can be a wood-based panel, such as an MDF or HDF panel. However, it can also be a plastic or compact panel made of kraft paper impregnated with phenolic resin. The top layer 4 typically consists of at least one melamine resin-impregnated decorative paper and an overlying melamine resin-impregnated overlay, which were hot-pressed together with the carrier plate 5 and the counter-layer 6 to form the material 1. This bonds the layers of the laminate to one another, and the melamine or synthetic resin hardens.On the upper side of the uppermost layer 4 of the material 1 there is a surface made of a plastic 2 containing amino groups due to the cured melamine resin present there. The amino groups are terminally remaining primary amino groups and the secondary amino groups of the cured melamine resin (melamine-formaldehyde resin).

[0129] Also visible in the cross section is the Fig. 1the structuring 3 of the surface already shown in plan view, which is shown schematically here as depressions, such as can be created, for example, during production using structured press plates. Of course, however, applied structuring measures are also possible (e.g. 3D printing), which would then lead to elevations in the surface or a combination of elevations and depressions. The surface shown made of amino group-containing plastic 2 can already have been functionalized with vinyl groups according to the invention, in which case the material 1 is a material 1' that can be painted according to the invention. Otherwise, the material 1 shown is the starting material for the process according to the invention for producing the paintable material 1'.

[0130] The Fig. 2bThe material 1 shown represents a laminate, e.g. a compact board. The core 7 is formed by a stack of kraft paper impregnated with phenolic resin (e.g. 90 layers), the top layer 4 can again be Fig. 2a It is a melamine resin-impregnated decorative paper and a melamine resin-impregnated overlay, which were hot-pressed together with the core 7 of impregnated papers to form the material 1. The remaining features are as follows: Fig. 2a what has already been said accordingly.

[0131] As in Fig. 2cAs shown, the material 1 can also be just a carrier plate 5 provided with a structure 3. This has a surface made of a plastic 2 containing amino groups. The carrier plate 5 can, for example, consist of the plastic 2 containing amino groups or be coated with it. The carrier plate 5 can also be a wood-based panel (e.g. chipboard, fiberboard or OSB board) obtained from lignocellulose-containing particles that were glued with an aminoplastic binder and pressed to the wood-based panel. The amino groups on the surface 2 are then terminally remaining primary amino groups and the secondary amino groups of the cured aminoplastic resin. The carrier plate has a structure 3 at least on the upper surface 2. The following applies Fig. 2a Said accordingly.

[0132] Fig. 3shows a schematic detailed view of the reactions that take place at the Fig. 1 and 2 shown surface made of an amino group-containing plastic 2 during the functionalization according to the invention with the functionalization reagent 8. In Fig. 3a and Fig. 3cIn the surface of a plastic 2 containing amino groups, a single secondary amino group (-NHR) is shown representatively. It goes without saying that the surface of a plastic 2 containing amino groups will contain many such secondary, but also primary amino groups (-NH 2 ), each of which can also react accordingly with the functionalization reagent 8. The functionalization reagent 8 has at least three molecular moieties: (1) a first functional group A, which has a vinyl group 9, (2) a second functional group B, which is a group reactive toward the amino groups of the plastic 2 containing amino groups, and (3) the intermediate molecular moiety, referred to here as the "spacer" 10. In the case of more complex molecules, the spacer length refers to the shortest path between groups A and B.The spacer length is preferably between 2 and 20 carbon atoms, in particular between 2 and 10 carbon atoms, although other heteroatoms may be present between the carbon atoms. The functionalization reagent 8 is thus at least a bifunctional molecule, as it contains at least the functional groups A and B.

[0133] In Fig. 3a and 3b The functionalization reagent 8 is shown only schematically. Fig. 3a The functional group A shown can be any functional group that includes a vinyl group 9. Group A can also consist of a vinyl group. In the case of the Fig. 3aThe functional group B shown can be any group reactive towards the amino groups of the amino-containing plastic. Group B can be, for example, an epoxide, acid anhydride, acid chloride, acid azide, sulfonyl chloride, ketone, aldehyde, carboxylic acid, ester, in particular N-hydroxysuccinimide ester, imidoester, or carbonates, carbodiimide, isocyanate, isothiocyanate, alkyl halide, aryl halide, alkyne or a vinyl group, such as acrylate, methacrylate or acrylamide. Fig. 3c and 3d A specific functionalization reagent 8, hexanediol diacrylate (HDDA), is shown as an example. In this symmetrically constructed molecule, both group A and group B are acrylate groups. The spacer 10 consists of six -CH 2 - groups.

[0134] According to the invention, the functionalization reagent 8 is applied to the surface of a plastic 2 containing amino groups, so that it can be used in the Fig. 3a and 3cBy setting the appropriate reaction conditions, a reaction occurs on the surface 2 between the amino groups present there and the reactive group B of the functionalizing reagent 8, thus resulting in the grafting of the functionalizing reagent onto an amino group on the surface of the amino-containing plastic, forming a covalent bond 11 as in Figures 3b and 3d shown. Surface 2 was thus covalently functionalized with vinyl groups 9, which are now available for reaction with, for example, a radiation-curing lacquer. Fig. 3b and 3d ) thus show a detailed view of the functionalized surface of a material 1' which can be painted according to the invention.

[0135] The reaction conditions that exist between the Fig. 3a and 3b3c and 3d are symbolically represented by a reaction arrow, depend strongly on the nature and chemistry of the reactive group B in the functionalization reagent. If the reactive group B is a vinyl and especially an acrylate group, irradiation with high-energy radiation such as electron beams or UV light is sufficient to lead to the Fig. 3c and 3d shown Aza-Michael addition.

[0136] The material surfaces functionalized with vinyl groups can then be painted or stored. If a non-reversible reaction is chosen for the functionalization (e.g., Aza-Michael addition), the material surfaces functionalized with vinyl groups have proven to be easy to store. However, there are also advantages to further processing the functionalized material surfaces directly, in particular by painting, as this way excess functionalization reagent is not disruptive and can, in fact, polymerize directly into the paint layer. During storage, it is recommended to take precautions to avoid contamination or smearing, such as storing individual panels, storing them with an intermediate layer, or cleaning off the excess. According to a preferred embodiment, the functionalization with vinyl groups is immediately followed by painting of the functionalized material surface.

[0137] If you paint directly it doesn't matter because the reagent polymerizes in. Fig. 4a - 4c show the related to Fig. 2a - 2c already discussed materials, but this time after vinyl functionalization according to the invention and subsequent painting. Directly on the top layer 4 functionalized with vinyl groups (not shown) is now a layer of radiation-curing lacquer 12. For example, a commercially available acrylate top coat can be applied in a layer thickness of 5-15 g / m 2 directly onto a structured melamine resin surface functionalized according to the invention. Because primer or priming coats can be dispensed with according to the invention, the lacquer layer 12 can be applied so thinly that the structuring 3 present in the top layer 4 of the material 1 is retained even after painting (cf. Fig. 2a - 2c before painting with Fig. 4a - 4cafter painting). It is therefore possible, for example, to produce structured aminoplast resin surfaces, as used in Fig. 1 shown schematically in plan view, in lacquered form. The inventors have surprisingly discovered that if such a surface structuring 3 is combined with a matte lacquer 12 or excimer curing of the lacquer layer 12, natural-looking material surfaces are created that are virtually indistinguishable from the original (e.g., real wood parquet) in terms of appearance, feel, and temperature sensitivity, while simultaneously exhibiting improved surface properties (e.g., micro-scratch, weather, and chemical resistance).

[0138] Fig. 5 serves to illustrate the advantages of the invention over the prior art. In Fig. 5a is an enlargement of the cross-section through the top layer 4, as is also the case in the Fig. 2a - 2ccan be seen. The uppermost layer 4 has a structure 3 and consists of or contains a plastic containing amino groups (e.g. a melamine resin), whereby it has a surface made of amino group-containing plastic 2. If one wanted to paint such a melamine resin surface according to the prior art with a radiation-curing paint 12 (e.g. an acrylate paint), one would first have to apply a primer layer 13 to the structured melamine resin surface, since radiation-curing paints adhere only poorly to this. The multi-layer paint structure 12, 13 results in a considerable paint layer thickness compared to the largest height and depth difference in the structure 3 (Rz value). The structure is lost through overpainting. According to the prior art, it therefore makes no sense to, for example, paint a melamine resin surface provided with a wood structure (cf. Fig. 1), which is often used, for example, as a furniture surface or flooring laminate. Such a varnish would destroy the originally introduced texture.

[0139] The invention, however, makes it possible to overcoat structured aminoplast resin surfaces. Fig. 5c shows a paintable surface according to the invention, similar to Fig. 5a as an enlargement of the cross-section through the top layer 4, as is also the case in the Fig. 2a - 2c can be seen. As in Fig. 5a also has the top layer 4 in Fig. 5c a surface made of amino group-containing plastic 2, into which a structuring 3 has been inserted. As can be seen from a comparison of Fig. 5a As can be seen from Figure 5c, the paintable material 1' according to the invention has Fig. 5c However, a surface functionalized with vinyl groups 9 (see Fig. 3b and 3d ). As in Fig. 5dAs shown, a layer of radiation-curing lacquer 12 can be applied directly to this surface functionalized with vinyl groups 9 according to the invention, without the need to apply a primer or priming layer 13 beforehand. Fig. 5dshows the applied layer of radiation-curing lacquer before radiation curing, as can be seen from the vinyl groups 9 still present. During the radiation-induced radical polymerization of the lacquer layer 12, the vinyl groups 9 present on the surface 2 polymerize into the lacquer film, which is thereby covalently anchored in the uppermost layer 4 of the material. This explains the observed excellent adhesion of radiation-curing lacquers to the paintable material surfaces provided by the invention. Since the vinyl groups 9 introduced into the surface 2 react into the lacquer during radiation curing, they are no longer detectable following radiation curing of the lacquer layer 12. In cross-section, a material painted according to the invention therefore simply appears as if no primer or undercoat layer had been used. Only the lacquer film itself is visible on the substrate.

[0140] In contrast to the state of the art (see Fig. 5c ) According to the invention, when painting a structured material surface, its structuring is retained even after painting, since significantly lower paint layer thicknesses can be achieved by omitting the primer or undercoat layer. Fig. 5d therefore shows the structured lacquer layer present in the material painted according to the invention, which corresponds to the structuring of the material surface before painting (cf. Fig. 5a or 5c with Fig. 5d ).

[0141] Fig. 6shows, by way of example, a system and a method for producing a material that can be painted according to the invention, which is subsequently directly processed into the material painted according to the invention. A wood-based panel as a carrier 5 with an underside counterweight 6 (shown as a liquid counterweight applied to the underside, the latter can also be fed via a separate fourth feed conveyor belt) as well as a melamine resin-impregnated decorative paper 18 and melamine resin-impregnated overlay 19 are placed on a feed conveyor belt 30 as a press stack 20 via a first, second and third feed conveyor belts 14, 15, 16. For the sake of simplicity, the feed conveyor belt 30 is shown as a continuous conveyor belt. In practice, however, there are several separate conveyor belts, the speeds and surface properties of which are adapted to the respective process step.The press stack 20 then passes through a short-cycle press 21, which is equipped with a structured press plate 22 on the side facing the overlay paper. In this example, the structure provided in the press plate is the negative image of the one shown in . Fig. 1shown wood grain. In the short-cycle press, the press stack is pressed at 180 °C to 230 °C and a specific pressing pressure (active pressure on the panel surface) of 50 to 300 N / cm² to form material 1, which is a laminate panel having a surface 2 containing amino groups and provided with a structure 3. Both terminal primary amino groups and secondary amino groups are present in the cured melamine resin on surface 2. Material 1 corresponds to a material with a structured surface known from the state of the art, as it is produced in many variations as floor coverings or furniture components and is already available in intermediate storage facilities.

[0142] The production of material 1 is in the upper part of the Fig. 6therefore shown only for the sake of completeness. Material 1 is storable, and the process can be interrupted at this point. Above all, in practice, the numerous existing materials 1 with structured, amino-containing surfaces 2, 3 can be used. These can be subjected to the inventive process for surface functionalization with subsequent coating without pretreatment. This is a further advantage of the inventive solution.

[0143] The material 1 with a structured, amino-group-containing surface 2, 3 is fed to a device 23 for applying the functionalization reagent 8 according to the invention. In the embodiment shown, a functionalization reagent with two acrylate groups is used (e.g., dipropylene glycol diacrylate, tripropylene glycol diacrylate, or hexanediol diacrylate). In the device 23, the functionalization reagent 8 is applied to the structured, amino-group-containing surface 2, 3 of the material 1. Fig. 6 The application of the functionalization reagent 8 in the device 23 is shown as a spraying. However, numerous alternative application methods as described in the description are also possible, in particular application via a roller as in Fig. 6 for the device for applying the radiation-curing lacquer 26.

[0144] In the next step, the applied functionalization reagent 8 is reacted with the amino groups on the surface 2 of the material by setting the appropriate reaction conditions. If the group in the functionalization reagent that is reactive toward the amino groups on the material surface is a vinyl group, especially one that is adjacent to an electron-withdrawing group (such as an acrylate group), the reaction can occur in the form of a radiation-induced aza-Michael addition.

[0145] For this purpose, the amino group-containing surface 2 of the material 1, which has been treated with functionalization reagent 8, is exposed to a radiation source 24. The high-energy radiation 25 (e.g., UV or electron beams) impinges on the surface 2 and leads to an aza-Michael addition of an acrylate group of the functionalization reagent 8 to amino groups in the surface 2 (cf. Fig. 3a - 3d). The functionalization reagent 8 is thereby grafted onto the surface 2 of the material, resulting in a covalent functionalization of the surface 2 with vinyl groups. The material 1' functionalized in this way represents the paintable material of the invention.

[0146] The paintable material 1' can be coated with a radiation-curing paint 12 directly afterward or in a separate process. For this purpose, the material 1' passes through a device 26 for applying the radiation-curing paint 12. In Fig. 6 The application of the lacquer in device 26 by means of a roller is shown, however, all other methods known to the person skilled in the art for applying radiation-curing lacquers are also possible. The applied layer 12 of radiation-curing lacquer is then cured in a manner known from the prior art by high-energy radiation 25, 28. In the Fig. 6In the system shown, in addition to the second radiation source 29 (e.g., a UV lamp or an electron beam) actually required for curing, an upstream excimer radiation source 27 is provided. In this, the applied lacquer layer is exposed to excimer radiation 28 (172 nm), which results in the microstructuring of the lacquer surface explained in more detail in the description. The lacquered material 1" thus obtained not only has a macroscopically structured lacquer surface, which corresponds to the surface structuring 3 present in the lacquerable material (e.g., wood grain, see top view in Fig. 1 ), but also a microstructuring that creates a special matting effect and also gives the surface of the material 1" anti-fingerprint properties.

[0147] Fig. 7shows a diagram illustrating the determination of the characteristic values ​​Rz, Rz Max, and Rt measured according to DIN EN ISO 4287. Rz is the average difference between the highest and lowest profiles (average of the five Rz values ​​1 to 5 shown); Rz Max is the highest measured point (largest Rz value determined); Rt is the total height of the profile (distance between the highest peak and the lowest valley of the profile over the entire evaluated length ln). Examples of implementation

[0148] In all examples, industrially manufactured laminate flooring or furniture surface panels with a textured melamine resin surface from EGGER were used. These were CPL boards with the following layer structure: backing, MDF core, melamine resin-impregnated decorative and overlay paper. The latter had the following structures embossed into them during pressing using appropriately designed press plates: ST67F870 Slate decorative paper, trade name "CERAMIC", with an irregular, rough texture (all-over texture / no synchronous texture). ST69 "Natural Pore" decorative paper - Authentic, true-to-decor wood grain combined with a synchronous surface texture. ST28 "Gladstone Oak" decorative paper (look of classic planked oak), combined with the synchronous surface texture of ST28 Feelwood Nature (feel of sandblasted oak). F1 Wood grain in an all-over texture. Test series 1

[0149] As indicated in the table below, the structured melamine resin surfaces of the boards were either not subjected to any treatment at all (Comparative Examples 1, 3, 5 and 8) or 0.5 g / m² of hexanediol diacrylate (HDDA) was applied by roller application and then irradiated with a UV lamp (inventive examples 2, 7 and 10; irradiation was carried out using an 80 watt mercury lamp, with a feed rate of 10 m / min with a UV-A dose of >350 mJ / cm²) or a commercially available UV primer for melamine resin surfaces (ICA UVF5782) was applied in an amount of 4 or 4-5 g / m² by roller application and gelled by UV irradiation (Comparative Examples 4, 6 and 9; irradiation was also carried out using an 80 watt mercury lamp, with a feed rate of 10 m / min with the dose of UV-A >350 mJ / cm 2< ).The surfaces, which had been vinyl-functionalized with HDDA according to the invention or primed according to the state of the art, were then coated with commercially available UV topcoat compositions (acrylate varnish, ICA UVS5595) and UV-cured according to the manufacturer's instructions. After the topcoat application, excimer curing (IST) was carried out at 15 m / min, followed by two irradiations with 120 W mercury lamps for final curing.

[0150] The gloss value at 60° and 85° was determined according to ÖNORM EN ISO 2813 (version 2015-01-01). The surface quality was also determined using the stylus method according to DIN EN ISO 4287 (version October 1998). The definition of the Rz value is as described in the description and in Fig. 7 specified.

[0151] Adhesion was determined using the "Hamberger Hobel," a standardized testing device from Hamberger Industriewerke, which allows a coin test to be conducted under defined conditions. A piece of metal with a coin-like edge is pushed over the painted surface with an adjustable pressure. The result is given as the force in Newtons at which no stress whitening is detectable. All results above 15 Newtons can generally be considered acceptable.

[0152] The following test results were obtained: Table 2 sample Functionalization with vinyl groups UV primer UV topcoat Gloss 60° Gloss 85° Rz ΔRz Hamberger plane 1* ST67 - - - 6,2 12,8 21,3 > 40 N 2 ST67 0.5 g / m 2< HDDA, UV - 7 g / m 2 3,2 6,9 24,9 3,6 > 40 N 3* ST69 - - - 5,2 10,6 61,1 > 40 N 4** ST69 - 4 g / m 2 12 g / m 2 1,8 14,2 22,1 -39,0 < 15 N 5* ST28 - - 4,1 10,8 55,1 - > 30 N 6** ST28 - 4-5 g / m 2 7-8 g / m 2 5,8 32,1 43,7 -11,4 < 10 N 7 ST28 0.5 g / m 2< HDDA, UV - 7 g / m 2 3 11,2 70,9 15,8 > 30 N 8* F1 - - 8,4 23,2 35,1 > 40 N 9** F1 - 4-5 g / m 2 7-8 g / m 2 7,6 28,4 28,4 -6,7 < 15 N 10 F1 0.5 g / m 2< HDDA, UV - 7 g / m 2 3,1 12,3 38,0 2,9 > 40 N * Not according to the invention (starting product, structured melamine resin surface) ** Not according to the invention (overcoated with UV primer and UV varnish)

[0153] A comparison of samples 1* and 2 shows that, with the functionalization according to the invention, it is possible to apply a UV varnish directly to a melamine resin surface without impairing the adhesive bond (Hamberger Hobel Coin Test). By using a matte UV varnish, the unnaturally high-gloss melamine resin surface can be given a matte appearance (gloss 60° at approx. 3, cf. inventive examples 2, 7, and 10 with the corresponding melamine resin surfaces 1*, 5*, and 8*) while still maintaining or even enhancing its textured surface, which matches the decor (difference [Δ] in the Rz values ​​unchanged to positive in inventive examples 2, 7, and 10).In contrast, the application of a layer of standard UV primer followed by painting leads to a strong decrease in the Rz value after painting even with the relatively thin layer thicknesses used (usually up to 10 g / m 2< for UV primers and up to 15 g / m 2< for topcoats) (see negative difference [Δ] of the Rz values ​​in the comparative examples 4**, 6** and 9**).

[0154] In addition, the micro-scratch resistance of the surfaces was determined according to DIN EN 16094 (Martin Dale standard for flooring). (Rating 1 - 5; 1 best rating, 5 worst ratings)

[0155] Surface - unpainted, (samples 1*, 3*, 5* and 9*) Surface - painted (samples 2, 7 and 10) Martin Dale Exam A >A2 A1 Martin Dale Exam B >B3 B1

[0156] While the unpainted melamine resin surfaces were very susceptible to micro-scratches, the micro-scratch resistance could be significantly increased by the coating according to the invention, while preserving the original structure.

[0157] Samples 1 to 10 were further assessed in a blind test by trained experts from EGGER. This assessment revealed that the inventive samples 2, 7, and 10 had by far the most natural appearance of all 10 samples and were barely distinguishable from the original (veneer / real wood surface, stone / ceramic decors, or textile decor with a smooth texture) in terms of their appearance, feel, and touch temperature. Test series 2

[0158] Similar results to those obtained with the UV primer ICA UVF5782 and topcoat ICA UVS5595 used in test series 1 were also obtained in numerous tests with other commercially available UV primers (tested: Plantag 74170, Remmers UV120-112, Teknos E114203, Sherwin Williams UL / 61099-469, Votteler L5405524) and topcoats (tested: Plantag 75773.6, Teknos E120239, Bergolin 2U073, Bona 7720, Akzo Nobel UV TOP 103939). The vinyl functionalization according to the invention was consistently superior to the commercially available UV primers due to its lower film thickness and better adhesion. Test series 3

[0159] A series of tests was conducted as described for Test Series 1, except that BDDA was used as the functionalization reagent instead of HDDA. The results were similarly good as in Test Series 1. The vinyl functionalization according to the invention was always superior to commercially available UV primers due to its lower layer thickness and better adhesion. Test series 4

[0160] A series of tests was conducted as described for Test Series 1, except that DPGDA was used as the functionalization reagent instead of HDDA. The results were similarly good as in Test Series 1. The vinyl functionalization according to the invention was always superior to the commercially available UV primers due to the lower layer thickness and better adhesion. Test series 5

[0161] A series of tests was conducted as described for Test Series 1, except that TMPTA was used as the functionalization reagent instead of HDDA. The results were similarly good as in Test Series 1. The vinyl functionalization according to the invention was always superior to the commercially available UV primers due to the lower layer thickness and better adhesion. Test series 6 Example 1:

[0162] In a manner analogous to that described for test series 1, a furniture surface (H3399 decor) with the ST28 structure (raw sample) was functionalized with HDDA (1 g / m²). For the comparison example, a commercially available UV primer (Plantag Primer 74170.5) was used instead at an application rate of 4 g / m². According to the technical data sheet, this primer contains: propylidynetrimethanol, ethoxylated, ester with acrylic acid; 2-ethylhexyl acrylate; and 2-hydroxy-3-phenoxypropyl acrylate. In both cases, a UV varnish from Plantag 78700.1 (8 g / m²) was applied as the topcoat. According to the technical data sheet, this contains: 1,6-hexanediol diacrylate, acrylic resin, and methyl benzoyl formate. However, in contrast to test series 1, no excimer curing was performed. The following results were obtained: Rt value Gloss level Hamberger plane Martin Dale (DIN EN 16094) raw samples 78,8 µm 4,1 (60°) 40 N B2 / A3 HDDA + Plantag top coat 78700.1 78 µm 7,3 (60°) 40 N B1 / A1 Plantag Primer 74170.5 + Plantag Top Coat 78700.1 73 µm 8,5 (60°) 10 N B1 / A1 Example 2:

[0163] In a manner analogous to that described for test series 1, a floor panel with wood decor H1007 "Parquet Oak" and a flatter surface structure was functionalized with DPGDA (application rate 1.5 g / m²). For the comparison example, a commercially available UV primer (UVILUX Primer 621-183) was used instead at an application rate of 4 g / m². According to the technical data sheet, this primer contains: exo-1,7,7-trimethylbicyclo[2.2.1]hept-2-yl acrylate, dipropylene glycol diacrylate, 2-propenoic acid, 2-methyl-, 2-hydroxyethyl ester, and ethylphenyl(2,4,6-trimethylbenzoyl)phosphinate. In both cases, a UV topcoat from Bona (Article No. 7720, acrylic varnish, application rate 8 g / m²) was applied and cured with excimer as described in test series 1. The following results were obtained: Rt value Gloss level Hamberger plane Martin Dale (DIN EN 16094) raw samples 49 µm 8,4 (60°) 40 N B2 / A3 DPGDA + Bona UT 7720 47,2 µm 3,1 (60°) 40 N B1 / A1 UVILUX Primer 621-183 + Bona UT 7720 36 µm 3,3 (60°) 12 N B1 / A1 Example 3:

[0164] In a manner analogous to that described for test series 1, a panel with a synchronous structure ST 69 on the wood decor H2820 was functionalized with 0.5 g / m² of TMPTA. For the comparison example, a commercially available UV primer (Bergolin 1U080) was used instead at an application rate of 4 g / m². According to the technical data sheet, this primer contains: 4-(1,1-dimethyl)cyclohexyl acrylate, (5-ethyl-1,3-dioxan-5-yl)methyl acrylate, ethyl phenyl (2,4,6-trimethylbenzoyl) phosphinate, and 1,1,1-trihydroxymethylpropyl triacrylate. In both cases, Bergolin UV Topcoat 2U080-090, colorless (unsaturated acrylic resin, 11 g / m 2< ) was used as topcoat and cured with excimer as described in test series 1.According to the technical data sheet, the topcoat contains: 1,6-hexanediol diacrylate, (5-ethyl-1,3-dioxan-5-yl)methyl acrylate, bis(1,2,2,6,6-pentamethyl-4-piperidyl) sebacate, ethyl phenyl (2,4,6-trimethylbenzoyl) phosphinate, methyl 1,2,2,6,6-pentamethyl-4-piperidyl sebacate, and 1,1,1-trihydroxymethylpropyl triacrylate. The following results were obtained: . Rt value Gloss level Hamberger plane Martin Dale (DIN EN 16094) raw samples 65 µm 10,4 (60°) 35 N B2 / A3 TMPTA + Bergolin 2U080 63,8 µm 1,8 (60°) 35 N B1 / A1 Bergolin 1U080 + Bergolin 2U080 54,2 µm 5,2 (60°) 10 N B2 / A2

[0165] As a comparison of the Rt values ​​for Examples 1 to 3 shows, the structure is always best preserved with the coating according to the invention. Surfaces coated according to the invention exhibit similarly good Hamberger Planer results as the original melamine resin surfaces (raw samples), but achieve similarly good results in the Martin Dale test as melamine resin surfaces coated with UV varnish.

Claims

1. Paintable material comprising a surface comprising an amino group-containing plastics material, characterized in that the surface is structured and in that at least a portion of the amino groups on the structured surface of the amino group-containing plastics material has been covalently functionalized with vinyl groups by means of grafting a functionalizing reagent, wherein the functionalizing reagent comprises at least one vinyl group and at least one group that is reactive toward the amino groups of the amino group-containing plastics material, wherein the paintable material is able to be painted with a vinyl group-mediated radiation-curing paint.

2. Paintable material according to claim 1, characterized in that the functionalizing reagent has a molecular weight from 90 to 2000, preferably from 95 to 1100, and more preferably from 95 to 600.

3. Paintable material according to either of the preceding claims, characterized in that the further group in the functionalizing reagent that is reactive toward the amino groups of the amino group-containing plastics material is selected from the group consisting of epoxides, anhydrides, acid chlorides, acid azides, sulfonyl chlorides, ketones, aldehydes, carboxylic acids, esters, in particular N-hydroxysuccinimide esters, imido esters, or carbonates, carbodiimides, isocyanates, isothiocyanates, alkyl halides, aryl halides, alkynes and vinyl groups such as e.g. acrylate, methacrylate, or acrylamide.

4. Paintable material according to any of the preceding claims, characterized in that the further group in the functionalizing reagent that is reactive toward the amino groups of the amino group-containing plastics material is also a vinyl group.

5. Paintable material according to any of the preceding claims, characterized in that the structured surface of the amino group-containing plastics material is functionalized by means of grafting, by applying the functionalizing reagent in an amount of less than 5 g / m2, in particular less than 2 g / m2 or less than 1 g / m2, and subsequently heating or irradiating it using UV or electron beams.

6. Paintable material according to claim 3 or 4, characterized in that the functionalizing reagent is selected from the group consisting of di-, tri-, tetra-, penta- or even higher functional acrylates, methacrylates, vinyl ethers and allyl ethers, it being possible for the functionalizing reagent in particular to be selected from the group consisting of trimethylolpropane triacrylate, dipropylene glycol diacrylate, tripropylene glycol diacrylate, hexanediol diacrylate, pentaerythritol tetraacrylate, dipentaerythritol pentaacrylate, dipentaerythritol hexaacrylate, neopentyl glycol diacrylate, and propoxylated or ethoxylated variants of these compounds, polyalkylene glycol diacrylates, in particular polyethylene glycol diacrylates, divinyl ethers, in particular diethylene glycol divinyl ethers, triethylene glycol divinyl ethers or cyclohexanedimethanol divinyl ethers, and diallyl ethers.

7. Paintable material according to any of the preceding claims, characterized in that the vinyl groups in the material surface and / or in the functionalizing reagent are selected from the group consisting of acrylates, methacrylates, vinyl ethers, allyl ethers and vinyl aromatic compounds, the latter being selected in particular from styrene, C1-4 alkyl-substituted styrene, stilbene, vinylbenzyldimethylamine, (4-vinylbenzyl)dimethylaminoethyl ether, N,N-dimethylaminoethylstyrene, tert-butoxystyrene and vinylpyridine.

8. Paintable material according to any of the preceding claims, characterized in that the amino group-containing plastics material is selected from the group consisting of aminoplast resins, aminopolysiloxanes, polyvinylamines, polyalkylene imines, aminoepoxide resins, and polyurethanes that have terminal amino groups.

9. Paintable material according to claim 8, characterized in that the amino group-containing plastics material is an aminoplast resin, in particular a melamine-formaldehyde resin or a melamine-urea-formaldehyde resin.

10. Paintable material according to any of the preceding claims, characterized in that the material is a sheet-shaped or board-shaped material, in particular a wooden material board; a carrier coated with an amino group-containing plastics material; an impregnated or coated paper or a laminate containing one or more impregnated or coated papers, in particular a DPL, HPL or CPL, a compact board or another layered material.

11. Painted material having a structured paint surface that can be obtained by: (a) providing a paintable material according to any of claims 1 to 10, (b) applying a layer of a vinyl group-mediated radiation-curing paint to the vinyl group-modified, structured plastics-material surface of the material, (c) radiation curing the paint layer.

12. Painted material according to claim 11, characterized in that the radiation-curing paint is a topcoat and the painted material does not contain a paint primer layer or undercoat layer.

13. Painted material according to claim 11 or 12, characterized in that in total, the amount of radiation-curing paint applied to the plastics-material surface is less than 20 g / m2, in particular less than 15 g / m2 or less than 10 g / m2.

14. Painted material according to any of claims 11 to 13, characterized in that the paint layer is an excimer-cured paint layer.

15. Painted material according to any of claims 11 to 13, characterized in that the paint layer is an excimer-cured paint layer and has a gloss value of less than 10, preferably less than 5, in each case measured according to EN ISO 2813 using the geometry of 60°.

16. Painted material according to any of claims 11 to 13, characterized in that the paint layer is a matte paint and has a gloss value of less than 10, preferably less than 5, in each case measured according to EN ISO 2813 using the geometry of 60°.

17. Paintable material according to any of claims 1 to 10 or painted material according to any of claims 11 to 16, characterized in that the structured material surface or the structured paint surface has an Rz value measured according to DIN EN ISO 4287 of at least 10 µm, in particular at least 15 µm or at least 20 µm.

18. Paintable material or painted material according to claim 17, characterized in that the surface structure of the structured material surface or the structured paint surface is a decorative structure which is initially produced by embossing, lamination, calendering, etching, lazering or printing and in particular represents the surface structure of wood, natural stone, artificial stone, ceramics, metal, mosaics, planks, tiles, joints or another decorative structure visible to the naked eye.

19. Method for producing a paintable material according to any of claims 1 to 10, comprising the following steps: a) providing a material with a structured surface made of an amino group-containing plastics material, wherein the material can be painted with a vinyl group-mediated radiation-curing paint, b) covalently functionalizing the structured surface with vinyl groups by (i) bringing the structured surface into contact with a functionalizing reagent that comprises at least one vinyl group and at least one further group that is reactive toward the amino groups of the amino group-containing plastics material, and (ii) performing a chemical reaction to create a covalent bond between the second reactive group of the functionalizing reagent and an amino group on the structured surface of the amino group-containing plastics material, as a result of which a structured surface covalently modified with vinyl groups is obtained.

20. Method for producing a painted material having a structured paint surface according to any of claims 11 to 18, comprising the following steps: a) performing a method according to claim 19, or providing a paintable material according to any of claims 1 to 10, b) applying a layer of vinyl group-mediated radiation-curing paint to the structured surface of the material that has been functionalized with vinyl groups, c) radiation curing the paint layer.

21. Use of vinyl functionalization as a substitute for a primer layer or undercoat in the painting of structured surfaces made of amino group-containing plastics material using vinyl group-mediated radiation-curing paints.