EP4179013A1

EP4179013A1 - Paintable and painted materials having structured surfaces

Info

Publication number: EP4179013A1
Application number: EP21740029.0A
Authority: EP
Inventors: Frank Kemmerling
Original assignee: Fritz Egger GmbH and Co OG
Current assignee: Fritz Egger GmbH and Co OG
Priority date: 2020-07-07
Filing date: 2021-07-06
Publication date: 2023-05-17
Also published as: CN115836106A; US20230303791A1; WO2022008493A1; EP3936559A1; DE112021003631A5

Abstract

The invention relates to a paintable material (1) having a structured surface made of plastic (2, 3) containing amino groups, wherein at least a part of the amino groups on the structured surface has been functionalized covalently with vinyl groups by grafting a functionalizing reagent. Painted materials having structured paint surfaces can be obtained from these paintable material, wherein the invention also relates to said painted materials as well as to their production methods. The invention further relates to the use of a vinyl functionalization as a substitute for a primer layer or foundation in the painting of structured surfaces made of plastic containing amino groups with radiation-curing paints.

Description

Paintable and painted materials with structured surfaces

The invention relates to materials with structured surfaces made from plastics containing amino groups, which are particularly suitable for subsequent painting, structured surfaces made from plastics containing amino groups which have been painted, processes for their production, and the use of vinyl functionalization in the painting of structured surfaces plastics containing amino groups.

BACKGROUND OF THE INVENTION

When using materials in furniture construction or for cladding floors, walls or ceilings, it is often desirable to design their surfaces in such a way that they not only have the look but also the feel of natural models such as wood, ceramics or stone. For this purpose it is known in the prior art to produce correspondingly structured decorations on material panels.

In the production of floor laminate, for example, the procedure is usually as follows: First, an impregnated decorative paper (so-called impregnate) is produced by printing the desired decor (wood grain, ceramic, mosaic, tile, etc.) onto a paper web and this then impregnated with amino resin. The impregnate obtained in this way can be rolled up onto a roll or placed in sheets and stored. In a second step, a carrier board (eg MDF, HDF, chipboard or the like) is coated with the impregnate. For this purpose, the impregnate and, if necessary, further aminoplast resin-impregnated underlay and overlay papers are placed on the carrier board and then pressed with the wood-based panel in a press under the influence of heat. Under the influence of pressure and temperature, the resin melts, forming a homogeneous film layer and the paper at the same time is glued to the wooden substrate. The upper press plate of the press can be provided with a matrix as a relief, which advantageously matches the decoration. During pressing, depressions are then formed in the aminoplast resin surface through the corresponding imprints of the pressing plate, which imitate, 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 form a surface on the wood-based material board that is as lifelike as possible. The surface of the aminoplast resin layer forms the negative structure of the press plates used. In a similar way, other material surfaces made of plastics containing amino groups can also be structured during production. Thus, amino resins can also be applied in powder form and pressed with carriers, or a carrier can be separately coated with an amino resin or another plastic containing amino groups. Materials that already consist of plastics containing amino groups or contain them as a binder (such as the majority of chipboard and fibreboard) can also be provided with a structured surface. In addition to embossing using structured press plates, decorative structures can also be created using lamination, calendering, etching, lasering or three-dimensional printing.

A disadvantage of the prior art, however, has hitherto been the poor paintability of surfaces made of plastics containing amino groups and provided with decorative structures. Current radiation-curing paints adhere poorly to plastic surfaces containing amino groups. For this reason, primer layers or primers must be applied as adhesion promoter layers before the actual painting of the plastic surface with radiation-curing paints can take place. For the particularly difficult to paint melamine resin surfaces, special primer layers or hot-melt adhesives have been developed, for example, which are applied directly to the aminoplast resin surfaces and can then serve as the basis for one or more further paint layers. However, due to this necessarily multi-layered and thus thick paint structure, an underlying structure of the surface is lost during painting (see FIG. 5b).

However, it would be desirable to be able to paint structured surfaces while retaining the structure. As a result, the optical and decorative effects of structured surfaces explained at the beginning could be combined with those of a paint finish. Particularly in the case of plastic surfaces containing amino groups and, in particular, in the case of amino resin surfaces, overcoating would often be necessary in order to achieve the desired surface properties.

It is true that plastics containing amino groups in general and amino resins in particular have good hardness, chemical resistance and heat and fire resistance. However, there are also disadvantages in terms of surface properties.

A disadvantage, particularly on amino resin surfaces, is the high degree of gloss, which is perceived as disruptive precisely when the aim is to imitate natural surfaces, since these usually have a much duller appearance. Many consumers perceive a matt surface as a resting point for the eye in contrast to an obtrusive high-gloss surface. It is also advantageous that unevenness in the substrate is optically compensated more effectively by matt surfaces than by glossy surfaces. The high degree of gloss also means that aminoplast resin surfaces are optically very susceptible to soiling of an organic nature, such as food residues, grease and, above all, fingerprints. Such soiling is very easily noticed on high-gloss plastic surfaces and affects the decorative effect or makes the surface appear dirty and unhygienic.

In order to adjust the degree of gloss and in particular to avoid soiling from fingerprints, aminoplast resin surfaces are partially coated over. Specially developed so-called anti-fingerprint coatings available. But apart from the anti-fingerprint effect, it is often advisable to coat the aminoplast resin surface with a matt lacquer for the reasons mentioned above. The wood and furniture industry is one of the largest consumers of matt, matt or semi-matt UV coatings specially developed for this branch of industry. Synthetic silicic acids, for example, are used as matting agents. However, with UV coatings it is also possible to achieve matt effects physically, ie without adding matting agents. So-called excimer UV curing can be used to create particularly microstructured and therefore matt surfaces (see e.g. Jorge and Kiene. Wood coating. FARBE UND LACK, 2019, pp. 132-133).

Plastic surfaces containing amino groups, and in particular melamine surfaces, are sometimes perceived by consumers as artificial because they "feel cold". This can also be improved by structuring the surface or painting over it.

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 microscratch resistance. For this reason too, in practice, aminoplast resin surfaces are often overcoated with more resistant UV coating systems. For example, UV topcoats with very high paint hardness and scratch resistance are known from the field of parquet coating. In the case of aminoplast resin surfaces, it is particularly important to increase the micro-scratch resistance.

Unfortunately, it has not been possible in the prior art to combine the optical and decorative advantages of structured material surfaces made of plastics containing amino groups with those of coating with radiation-curing coatings in a simple and inexpensive manner. SUMMARY OF THE INVENTION

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 inexpensive manner.

This object is achieved according to the invention by the paintable material according to claim 1, the painted material according to claim 12, the methods for their production according to claims 18 and 19 and the use according to claim 20. Particular configurations of the invention are reproduced in the dependent claims and are explained in more detail below, as well as the general idea of the invention.

The invention provides a material with 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 on a functionalizing reagent. This surface functionalization makes it possible to dispense with a primer layer or primer. The structured surface according to the invention can be painted directly. For this reason, this first subject matter of the invention is also referred to herein as “paintable material”.

The paintable material according to the invention can be produced by the method 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

(i) contacting the structured surface with a

Functionalization reagent which has at least one vinyl group and has at least one further group which is 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 vinyl group covalently modified structured surface is obtained.

The advantage of the paintable material provided by the invention is that it can be painted with a correspondingly thinner paint layer by dispensing with a primer layer or primer, whereby the structure originally present in the substrate is retained after painting. For the first time, lacquer surfaces structured in this way can be produced on plastics containing amino groups in a particularly simple and cost-effective manner.

Accordingly, the invention also provides a painted material with a structured paint surface, which can be obtained by painting 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 radiation-curable paint to the vinyl-modified, textured plastic surface of the paintable material, and

(c) Radiation curing of the lacquer layer.

The invention therefore also includes, in particular, the use of a vinyl functionalization as a replacement for a primer layer or base coat when coating structured surfaces made of plastic containing amino groups. As a result, a significant reduction in the thickness of the paint layer can be achieved, making it possible for the first time to paint structured substrates while retaining the surface structure. DETAILED DESCRIPTION OF THE INVENTION

Plastic containing amino groups

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

According to a particularly preferred embodiment, the plastic containing amino groups is an amino 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 laminates, laminates and/or wood-based materials, it is known to coat their surface with a layer of amino resin (typically a melamine-formaldehyde resin in practice), for example in the form of a so-called liquid overlay or impregnated overlay paper. In practice, amino resins are also usually used as impregnating resins or binders for the underlying layers. In the wood processing industry Aminoplast resins are generally known to those skilled in the art, in addition to impregnating, soaking and/or coating surfaces, especially as glues, for example for the production of chipboard or fibreboard. Here, too, surfaces made of plastics containing amino groups occur. However, amino resins can also be applied in powder form to carrier materials and pressed with them. All of these uses of amino resins known to those skilled in the art lead to materials with surfaces made of a plastic containing amino groups within the meaning of the invention.

Aminoplast resins or aminoplasts are described in "Ullmann's Encyclopedia of Industrial Chemistry", 4th edition, 1974, in the chapter "Aminoplaste" in Volume 7 or in "Holzinstrumente und Leime" by Dunky and Niemz, 1st edition, 2002, in Volume 1, Part 11, Chapter 1 described. The term aminoplasts is generally understood to mean condensation products which are obtained by reacting a carbonyl compound, usually formaldehyde in practice, with a component containing amino, imino or amide groups.

According to the invention, the most important representatives of the amino resins are melamine-formaldehyde resins. These include all amino resins that are formed at least from melamine and formaldehyde, ie, for example, the melamine-urea-formaldehyde resins. The latter are amino resins formed at least from 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, and also additives and/or solvents. Melamine-formaldehyde resins, which are also referred to simply as melamine resin or melamine surfaces by those skilled in the art, have become established as surfaces in particular in the manufacture of furniture and in materials for interior design. Here in particular there is a great need for both structured and painted surfaces, as explained at the beginning. The situation explained at the outset is particularly relevant in the case of melamine-containing amino resin surfaces Problem of the undesired degree of gloss and the associated artificial look and feel in particular.

Polyvinylamines are polymer-analogous reactions such as by hydrolysis of poly-N-vinylamides such as poly-N-vinylformamide or poly-N-vinylacetamide, or poly-N-vinylimides such as poly-N-vinylsuccinimide, prepared by the polymerization of the corresponding Monomers are readily available, or prepared from polyacrylamide by Hofmann degradation.

Polyalkyleneimines are polymers having an N-atom-containing backbone linked by alkylene groups, which backbone can carry 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; if appropriate, it can also have only secondary amino functions in the interior, so that the result is not a branched-chain but a linear 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.

Amino-epoxy resins are obtained by reacting epoxy resins with polyamines as hardeners, the reaction conditions being chosen such that terminal amino groups remain in the resin after the reaction. Epoxy resins are synthetic resins that carry epoxy groups. They are hardenable resins (reactive resins) that can be converted with a hardener and, if necessary, other additives to form a thermosetting plastic. The epoxy resins are polyethers, usually with two terminal epoxy groups. The hardening agents are reactants and, together with the resin, form the macromolecular plastic. Amino-epoxy resins as used here represent such a macromolecular plastic, which was obtained by reacting epoxy resins with polyamines as hardeners. be there the reaction conditions are chosen so that terminal amino groups remain in the resin after the reaction.

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

material

The term "material" as used here includes any molded body that can be subjected to a coating. For example, it can be a furniture component or a component that is suitable for cladding floors, walls or ceilings. As explained at the beginning, it is often desirable, especially with these, to provide their surfaces with a structure so that they not only have the look but also the feel of natural models such as wood, ceramics or stone. For this purpose it is known in the prior art to produce correspondingly structured decorations on materials for furniture or components. In a preferred embodiment, the material that can be lacquered or lacquered according to the invention is a wood-based material board; a support 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.

The material that can be painted or painted according to the invention is preferably a sheet-like or plate-like 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, particularly if it is in the form of a sheet or plate, is suitable for producing furniture surfaces or for cladding floors, walls or ceilings. Sheet or plate-shaped materials have the advantage that they have a largely flat surface. This can be provided with structuring in a relatively simple manner and with a high throughput, for example by using structured pressed metal sheets 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 painting can also be applied particularly uniformly and extensively to sheet or plate-shaped materials, for example by rolling, spraying, spattering, flooding, dipping, pouring, doctor blade and/or brushing.

The sheet-like material can be rolled up onto a roll or stored in sheets. The sheet-like material can in particular be an impregnate or a laminate.

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 amino resin). Experts also refer to this as “impregnate”. According to another preferred embodiment, the material according to the invention is a laminate containing several papers impregnated and/or coated with a plastic containing amino groups (especially an amino resin), or a laminate containing one or more such papers and a carrier material. Laminates of several impregnated and/or coated papers and, if necessary, carriers are referred to as laminates. Both impregnated materials and laminates or layered materials are widely used in the production of furniture surfaces or for cladding floors, walls or ceilings, in particular for the production of floor panels.

Laminate, as used here, refers to a product that comprises at least two layers that are connected to one another over a large area. These layers can be of the same or different materials. Laminates according to the invention have a layered structure, the top layer having a decorative paper impregnated with an amino resin, overlay paper or a specially applied layer of amino 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 scratches.

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

If the material is a laminate, this can be designed in particular as a "direct pressure laminate" (DPL), "high pressure laminate" (HPL) or "continuous pressure laminate" (CPL). DPL are manufactured by pressing one or more layers of synthetic resin-impregnated paper together with a carrier plate under pressure and heat. HPL are manufactured by pressing several layers of synthetic resin-impregnated paper together under pressure and heat in a single or multi-daylight press. So it is a special embodiment of a laminate. The HPL can then be glued onto a carrier board, laminated or pressed with it under pressure and heat. CPL are manufactured by pressing several layers of synthetic resin-impregnated paper together in a continuously operating press, usually a double-belt press, under pressure and heat. The CPL is also a special embodiment of a laminate. A special form of the CPL is the continuous pressing of one or more layers of synthetic resin-impregnated paper with a carrier plate. All of the technologies mentioned are used for the production of furniture surfaces or for the production of components for cladding floors, walls or ceilings, in particular in the production of laminate flooring. Phenolic resins are often used as synthetic resins for impregnating the inner layers of paper. However, at least on the surface of the laminates or layered materials there are one or more papers, in particular decorative paper and overlay paper, impregnated with a plastic containing amino groups, in particular a melamine-formaldehyde resin. The latter is a transparent paper impregnated with melamine-formaldehyde resin, which serves as a protective layer and can contain additional anti-abrasive components. A decorative paper is a printed or colored special paper that is impregnated with amino resin and used for the decorative coating of wood-based materials.

The material according to the invention can be a compact laminate. This is understood to be a pressed laminated board that is produced in a similar way to HPL by pressing several layers of synthetic resin-impregnated paper together under the influence of pressure and heat. While HPL laminates are primarily used as a coating material and are applied to substrates, compact laminates can be designed on both sides and are used without substrates. According to DIN, compact laminates are abbreviated as DKS for decorative plastic laminate. They usually consist of several layers of paper or fabric covered in phenolic resin at the core and melamine as the outer layers. impregnated with formaldehyde resin and then joined together under heat and pressure.

The wood-based panel can be chipboard, OSB or fiberboard. What these have in common is that during their production, lignocellulose-containing particles (chips, strands or fibers) are glued with a binder and then pressed into the wood-based material. OSB boards (English for oriented strand board or oriented structural board, "board from aligned chips") are coarse particle boards that are made from long, slender chips ("strands") are made. Chipboard, OSB or fibreboard are mostly aminoplastically bonded wood-based panels.

In order to have a surface made of a plastic containing amino groups, the wood-based material board is either produced with a plastic containing amino groups as a binder or has subsequently been coated with a plastic containing amino groups or an impregnate or laminate or laminate containing a surface made of a plastic containing amino groups. The plastic containing amino groups is preferably an amino 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.

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

If the term "carrier", "carrier material" or "carrier board" is mentioned here or elsewhere, this can in particular be a wood-based material, mineral material, metal or plastic board. This also applies specifically to the previously described DPL, HPL and CPL embodiments. The information “wood”, “mineral”, “Metal” and “Plastic” the main quantitative (weight %) component of the carrier board. The carrier plate itself can also be a laminate or layered material.

Whenever “coating” or “coating” with the plastic containing amino groups is mentioned here or elsewhere, this means any form of coating. The plastic containing amino groups can be applied in liquid form, for example in the form of its monomers or precondensates, and then cured. However, the plastic containing amino groups can also be applied in powder form as a layer and then bonded, melted or cured. “Coating” or “coating” is understood here very generally to mean both the application of a layer of plastic containing amino groups and the pressing or laminating with one or more paper impregnated and/or coated with a plastic containing amino groups (in particular an amino resin).

A core aspect of the invention consists in making the structured surface of the material, consisting of a plastic containing amino groups, directly paintable by functionalization with vinyl groups. This eliminates the need for additional primer or priming layers. In the case of structured substrates, this has the advantage that the surface structure is retained even after painting.

In order to make this possible, according to the invention at least some of the amino groups on the structured surface of the plastic containing amino groups are covalently functionalized with vinyl groups by grafting on a functionalization reagent. The grafting takes place in that the structured material surface, which has a plastic containing amino groups, is brought into contact with the functionalization reagent and reacted. The plastic containing amino groups is thus covalently functionalized with vinyl groups in the cured state and thus only on its surface. The paintable material obtained according to the invention has vinyl groups on its surface which are anchored covalently in the plastic containing amino groups 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 anchored covalently in the plastic containing amino groups, which is located on the surface of the material. This leads to particularly good adhesion of the paint layer and makes it possible to dispense with a primer or undercoat layer.

In the context of the present invention, the term “vinyl group” includes any functional group which has a terminal C═C double bond. Such a double bond is suitable for taking part in the free-radical polymerization of a radiation-curing lacquer initiated by radiation curing.

Functionalization reagent, as used herein, means a molecule capable of being grafted onto an amino group present 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 plastic containing amino groups is functionalized with vinyl groups by the grafting of the functionalization reagent. The functionalization reagent is thus an at least bifunctional molecule (see FIGS. 3a and 3c). The first functional group A is a vinyl group. As the second functional or reactive group B, the functionalization reagent has a group that is reactive toward the amino groups of the plastic containing amino groups. The functionalization reagent thus has at least one vinyl group and at least one other group that is reactive toward the amino groups of the plastic containing amino groups. The grafting of the functionalization reagent consists in the further functional group B reacting with an amino group on the surface of the plastic containing amino groups, with the formation of a covalent bond has. This grafts vinyl groups onto amino groups present on the textured surface of the material. When amino groups are mentioned here, this means in particular terminal -NH 2 groups present in the plastic containing amino groups.

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

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 which has at least one vinyl group and at least one other group which is reactive towards the amino groups of the plastic containing amino groups. The bringing into contact takes place by applying the functionalizing reagent to the structured material surface, which has a plastic containing amino groups. The application can be done in many ways. According to the invention, it has been shown that functionalization of the surface with vinyl groups at specific points is sufficient to lead to a considerable improvement in adhesion as reactive binding anchors for the layer of radiation-curing lacquer to be applied later. Preferably, however, the functionalization reagent is applied to the surface of the structured surface of the plastic containing amino groups. The functionalization reagent can be applied, for example, by rolling, spraying, injecting, impregnating, pouring, squeegeeing and/or spreading.

The second step in covalently functionalizing the structured surface with vinyl groups is to react the functionalizing reagent with at least a portion of the primary and/or secondary amino groups present on the surface of the structured material. This step involves performing a chemical reaction to create a covalent bond between the second reactive group of the functionalizing reagent and a Amino group on the structured surface of the amino-containing plastic, whereby a structured surface covalently modified with vinyl groups is obtained.

The reaction takes place under reaction conditions which enable a covalent connection between the further reactive group B of the functionalizing reagent and the terminal amino groups of the aminoplast resin. The reaction conditions depend on the chemistry of the further reactive group B. In many cases it will be necessary to heat the material surface. This can be achieved using radiant heaters or stoves. After application of the functionalization reagent, the material surface is preferably heated to a surface temperature of 30.degree. C. to 100.degree. C., preferably 50.degree. C. to 80.degree. C. and particularly preferably 60.degree. C. to 70.degree. In other cases (such as, for example, in the case of 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/cm ² , preferably at least 150 mj/cm ² . The latter doses are required for reflective surfaces (e.g. for white surfaces). Good results have been achieved when the radiation dose is in a range from 100 to 1000, preferably from 150 to 600 mj/cm ² . 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 included under the term UV -Radiation summarized. The high-energy radiation is preferably one with a wavelength of 280 nm or less. UV-C radiation is particularly practical. Depending on the nature of the grafting reaction, it may also be necessary to apply the functionalization reagent together with any required catalysts, additives or solvents in one composition or separately from each other. A person skilled in the art can easily check whether the grafting reaction was successful by examining the adhesion of a lacquer layer on the material surface treated with the functionalizing reagent. Only when a covalent functionalization with vinyl groups - and thus a grafting of the functionalizing reagent - has occurred is very good adhesion achieved, even without the coat of paint primer or base coat that would otherwise be required.

Depending on the degree of conversion and the amount of functionalizing agent applied, it may be advisable to at least partially remove excess non-covalently attached functionalizing agent from the surface after the reaction before it is provided with a lacquer layer. The removal can be done simply by washing with a suitable solvent or wiping the surface. In practical testing of the invention, however, it has been shown that this is not necessary in many cases because, on the one hand, when the correct application quantities and reaction conditions are selected, an almost complete reaction occurs and on the other hand the functionalization reagents also polymerize into the paint layer during the free-radical polymerization of a radiation-curing paint due to the mandatory presence of the vinyl group and therefore do not interfere with the paint film formation.

Because of the variety of grafting chemistries available for amino group functionalization, the number of possibilities for the reactive group B and the associated reaction pathways is correspondingly large. The other group B of the functionalization reagent that is reactive towards the amino groups of the plastic containing amino groups can be selected in particular 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 acylate, methacylate or acylamide. 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 the acid amide or by alkylation to the secondary (or tertiary) amine. The reaction mechanisms and conditions are known to the person skilled in the art and can be looked up in the relevant textbooks on organic chemistry or in the relevant specialist journals.

According to a particularly preferred embodiment, the group in the functionalization reagent that is reactive toward the amino groups of the plastic containing amino groups is a vinyl group. In this particularly preferred embodiment, the functionalization reagent thus comprises at least two vinyl groups. The first is used for anchoring in the plastic containing amino groups, the second remains even after grafting and is used for later anchoring of the radiation-curing paint to be applied. The first and second vinyl groups can be identical or different from each other, preferably they are identical. The functionalization reagent is particularly preferably a mirror-symmetrical molecule with at least two vinyl groups.

The research on which this invention is based has shown that vinyl groups are extremely suitable 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 acylate group in the functionalization reagent is shown schematically below:

The corresponding reaction also takes place, or—as the inventors have found—above all with secondary amines in the plastic containing amino groups. This was recognized in test series where no difference was seen in the functionalization as a function of the number or the presence of primary amino groups in the plastic containing amino groups. Secondary amino groups appear to suffice in accordance with the invention.

Practical tests have shown that in the case of functionalization reagents with two vinyl groups, only one of the two reacts with amino groups on the surface of the material. The other remains, as desired, as a functionalization in the material surface. There are probably several reasons for this. On the one hand, it is a solid-phase or solid/liquid reaction, which means that the reactants are not mixed. It therefore seems sterically unlikely that the second vinyl group in the functionalization reagent, which protrudes from the material surface after it has been grafted on, "finds" another amino group in the surface to carry out another aza-Michael addition. However, this also applies to the molecular size and spacer length of

Functionalization reagents appear to play a role, as discussed 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.

The Aza-Michael reaction between a vinyl group of

Functionalization reagent and an amino group in the material surface the advantage that the functionalization reagent only has to be applied to the surface of the material and then subjected to high-energy radiation (such as UV light or electron beam) In the surface of the material, both primary and secondary amines can bind to the C=C double bond of the vinyl group of the Attach functionalization reagents in an aza-Michael addition.

For the aza-Michael addition, it is important that the high-energy radiation actually penetrates to the complexes of vinyl and amino groups that are initially formed. Only in this way are the electron-donor-acceptor or charge-transfer complexes required for the Michael addition formed and dissolved by addition to form the alkylamine. Since the amino group is located directly on the surface of the material, the complexes only form directly on the surface of the material. The layer of applied functionalization reagent must not be too thick, otherwise the high-energy radiation will not penetrate to the surface of the material. Particularly good results have been achieved when the functionalization reagent is applied in an amount of at most 3 g/m ² , preferably at most 2 g/m ² and particularly preferably at most 0.5 g/m ² or 1 g/m ² .

If the functionalization reagent is not applied in its pure form but in the form of a composition, this must not contain any substances that absorb the high-energy radiation. In particular, no photoinitiators or free-radical initiators, as is otherwise customary in paints, may be present, since these would not only intercept the high-energy radiation, but would also lead to free-radical polymerization of the vinyl-containing functionalization reagent, which is undesirable. Such a polymerization and film formation would mean that the vinyl groups intended for the functionalization would no longer be available and it would also prevent the high-energy radiation from penetrating to the material surface in order to trigger the desired aza-Michael reaction between the functionalization reagent and the material surface. For the same reason, functionalization of, for example, melamine resin surfaces with vinyl groups has also not occurred in the prior art when these surfaces have been coated with radiation-curing lacquers. On the one hand, the radiation is intercepted by the relatively thick layers of primer, base coat or paint applied in the prior art, and in particular by the radiation-absorbing molecules contained therein, such as photoinitiators, and does not reach the material surface. Thus, in the prior art, there are also no radiation-induced aza-Michael additions on the material surface. However, even if this were the case, all the vinyl groups contained in the primer, undercoat or coating composition react completely within a few seconds in the radiation-induced radical polymerization during radiation curing. This means that the surface of the material is not functionalized with vinyl groups.

In a preferred embodiment of the invention, the functionalization reagent is applied to the structured surface of the plastic containing amino groups ^{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 particularly advantageous if the functionalization reagent and the amino groups are reacted by means of high-energy radiation or if the other group contained in the functionalization reagent that is reactive toward the amino groups of the plastic containing amino groups is a vinyl group. For radiation-induced aza-Michael addition on the material surface in particular, it is essential that the high-energy radiation also reaches the surface.

However, even if the functionalization is not based on a radiation-induced aza-Michael addition, these application amounts have proven to be advantageous and sufficient. As explained at the outset, the inventors have recognized that the smallest possible layer thickness is necessary on the structured material surface in order to preserve its structure during subsequent painting. With this in mind, the “layer” of functionalization reagent should also be as thin as possible. It is also not useful in this context at all to speak of a layer, since the functionalization reagent reacts with the material surface and is then no longer recognizable as a separate layer.

After the functionalization reagent has been applied to the structured surface of the plastic containing amino groups, this is preferably irradiated with high-energy radiation, as described above. In the case of functionalization by means of aza-Michael additions in particular, this creates the preferred reaction conditions to ensure covalent attachment to the solid material surface. The type and intensity of the high-energy radiation should be selected in such a way that the complexes formed on the material surface between the functionalization reagent and amino groups are excited and react in aza-Michael reactions.

The vinyl groups in the functionalization reagent or in the functionalized material surface can in particular be selected from the group consisting of acylates, methacylates, vinyl ethers, allyl ethers and vinylaromatic compounds. The latter include, for example, styrene, Ci-4-alkyl-substituted styrene, stilbene, vinylbenzyldimethylamine, (4-vinylbenzyl)dimethylaminoethyl ether, N,N-dimethylaminoethylstyrene, tert-butoxystyrene and vinylpyridine. The group in the functionalization reagent which is reactive towards the amino groups of the plastic containing amino groups is particularly preferably an a,b-unsaturated carbonyl compound, in particular a,b-unsaturated carboxylic acid esters, or a,b-unsaturated carboxamides. Acrylic and/or methacrylic esters are particularly preferably a,b-unsaturated carbonyl compounds or compounds which are a,b-unsaturated in relation to another electron-withdrawing group are particularly suitable for aza-Michael additions. Preferably the vinyl group is a vinyl group directly attached to an electron withdrawing group such as a carbonyl group. 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 functionalizing reagent can be selected in particular from the group consisting of trimethylolpropane triacylate, dipropylene glycol diacrylate, tripropylene glycol diacrylate, hexanediol diacrylate, pentaerythritol tetraacrylate, dipentaerythritol pentaacylate, dipentaerythritol hexaacrylate, neopentyl glycol diacylate, and propoxylated or ethoxylated variants of these compounds, polyalkylene glycol diacylate, in particular polyethylene glycol diacylate, divinyl glycol diacylate

cyclohexane dimethanol divinyl ether, and diallyl ether. The molecular weights of some of these compounds are given below:

Table 1

When molecular weight thereof is mentioned, then so is the relative molecular weight (M _r) meant, ie to one-twelfth the mass of the carbon isotope ¹² C normalized molecular weight. The relative molecular weight therefore has no unit of measurement. According to the molecular weights given in the table above, the functionalization reagent is preferably a small molecule with a molecular weight of 90 to 2000, preferably 95 to 1100 and particularly preferably 95 to 600. This ensures that the part of the molecule between the vinyl groups ( "Spacer" 10, see Fig. 3) is as small as possible. The use of functionalizing 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 from 90 to at most 2000, preferably from 95 to at most 1100 and particularly preferably from 95 to at most 600. In the functionalized material surface, this means that the grafted vinyl groups are as close as possible to the material surface. This appears to result in better anchoring and adhesion of the later applied layer of radiation curable paint.

In addition, with shorter spacers, the probability is minimized that the functionalization reagent will fold back onto the surface containing amino groups after grafting and that the second vinyl group will also react with amino groups. 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 also not be a lacquer or a polymer.

Painted material

The above-described vinyl functionalization of the surface containing amino groups leads to a paintable material whose structured surface is retained even after painting. Accordingly, the invention also provides lacquered materials which are characterized in that they have a structured lacquered surface. These painted materials are obtainable by a process comprising the steps

(a) Providing a paintable material as previously described, i.e. 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 plastic containing amino groups have been covalently functionalized with vinyl groups by grafting on a functionalizing reagent;

(b) application of a layer of radiation-curing lacquer to the structured surface of the material functionalized with vinyl groups,

(c) Radiation curing of the lacquer layer.

Insofar as methods for achieving macroscopically structured paint surfaces are available at all in the prior art, these involve subsequent structuring of the paint surfaces. However, such methods have not become established due to insufficient practical suitability. For example, it has been proposed to apply a structuring film to the lacquer layer and then to remove this film again. On the one hand, it is very difficult here to apply the structure exactly to match a decor present on the substrate. On the other hand, it is also difficult to introduce deeper structures without damaging the lacquer layer or the underlying layers. In order to create deeper structures, as is necessary when imitating a wood structure, for example, correspondingly thicker layers of paint must be applied. This not only has cost disadvantages, but in practice also usually means several consecutive paint applications in order to achieve the appropriate layer thicknesses.

Finally, subsequent surface structuring of a paint also leads to defects in the paint surface and its microstructure. That is to say, a paint surface which has been structured subsequently differs greatly from a paint surface which is structured according to the invention and is intact, both macroscopically and microscopically. In the case of the structured paint surface according to the invention, the surface structure goes back to the structure already present in the substrate, which is merely painted. According to the invention is the macroscopic Structuring available directly after painting and does not have to be added to the paint afterwards.

If the term "structured" surface or "structuring" is used, then this means macroscopic structuring. This means a structure present in the surface, visible to the naked eye, which has a height and depth profile. The structuring is three-dimensional. The structured surface thus has a topography which can be felt by stroking it with the bare hand and which the viewer's eye perceives as a structure. "Structure", "structured surface", "surface structure", "topography" and "height and depth profile" are used synonymously here.

The surface structure of the structured material or paint surface according to the invention is in particular a decorative structure originally produced 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, ceramics, metal, mosaics, floorboards, tiles, joints or another decorative structure visible to the naked eye.

According to a particularly preferred embodiment, the paintable or painted material has a decoration, in particular a decoration, to which the structuring of the material or paint surface is matched. If the decor is a wood decor, for example, the structuring can consist of the three-dimensional imitation of the woodcut topography, ie grooves along the illustrated growth lines and indentations at the illustrated knotholes, etc. If the decor is a tiled floor or a mosaic, the structuring of this decor can be indented support according to the joints shown. In order to be able to perceive a macroscopic structure with the naked eye, it is necessary for the depressions and elevations in the surface structure or topography to be correspondingly pronounced. The surface quality of materials is quantified using DIN EN ISO 4287 using the so-called profile method. The characteristic values Rz, Rz Max and Rt measured here according to DIN EN ISO 4287 are determined as shown in FIG. 7 and are defined as follows. Rz: mean difference from highest and lowest profile;

Rz Max: highest point measured; Rt: total height of the profile (distance between the highest peak and the lowest valley of the profile over the entire length ln evaluated).

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, particularly preferably at least 15 μm and particularly 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 cannot be perceived as a structure with the naked eye. The Rz value, measured according to DIN EN ISO 4287, is preferably not more than 120 μm, particularly preferably not more than 100 μm and particularly preferably not more than 80 μm.

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. The painted material preferably does not contain any 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.

The expert differentiates between macroscopic and microscopic structures (so-called microstructure) on surfaces. Macroscopic structures are associated with the visible to the naked eye as a structure. These are what is meant 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 produced in a paint surface, for example, by means of excimer curing. The invention makes it possible, for example, to combine macroscopically structured amino resin surfaces with an excimer-cured lacquer layer.

Excimer curing is known to those skilled in the art and is used in practice on a large scale to matt paint surfaces. The matting is purely physical and does not require the addition of matting agents that would otherwise be necessary. Excimer curing is based on the following principle: In radiation-curing paints (e.g. acrylates), free radicals are formed by the 172 nm excimer lamp (e.g. Excirad 172), which trigger polymerisation and crosslinking. The penetration depth of the 172 nm photons in the acylate is between 0.1 and 0.5 nm, so that only a very thin surface layer is crosslinked. The shrinkage caused by the polymerization leads to microstructures. A wrinkled skin floats on the liquid film, which is then completely hardened with a second radiation source. A Hg-UV lamp, an electron beam or a long-wave excimer lamp with 308 nm can be used for this purpose. To avoid the formation of ozone, the irradiation takes place in a nitrogen atmosphere.

The physical microfolds created with the 172 nm exximer lamp make it possible to easily achieve gloss values from 1 to 10 in radiation-curing paints, measured for example according to EN ISO 2813 with the 60° geometry, without the addition of matting agents. The high-energy, short-wave 172-nm radiation leads to additional cross-linking of the monomers in addition to the free-radical polymerization of the acrylate groups. This increases the surface hardness considerably. The inventors have also found that excimer curing leads to an advantageous anti-fingerprint effect on paint surfaces. 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 by excimer curing, in the lacquer surface.

According to a preferred embodiment, the lacquered material is characterized in that the lacquer layer is an excimer-hardened lacquer layer.

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

The common plastics containing amino groups, in particular amino resins, are not amenable to excimer curing. However, decorative structures can be embossed particularly well into their surfaces during production, e.g. by means of appropriately structured rollers or pressing plates. The invention makes it possible to combine the macroscopic surface structures, e.g. produced by embossing, with excimer hardening in the course of painting. This leads to structured material surfaces that have an exceptionally natural matt finish and, when appropriate decors and structures are combined (e.g. laminate flooring as an imitation wood floor), can no longer be distinguished from the material to be imitated (e.g. real wood parquet). By appropriate microstructuring of the paint surface or the use of an appropriate paint, the invention also allows macroscopic surface structures, e.g. produced by embossing, to be equipped with anti-fingerprint properties for the first time.

This is made possible by the fact that, according to the invention, the vinyl functionalization of the material surface makes it possible to dispense with the primer coat or primer or spatula otherwise required when coating plastics containing amino groups, in particular aminoplast resins, with radiation-curing coatings. In the prior art, these lead to layer thicknesses in the paint structure of regularly over 20 or 30 g/m ² . A structuring of the subsoil Such a thick coat of paint inevitably evens out the surface, which is common, for example, when imitating wood structures and decors, and thus nullifies it. For this reason, in the prior art, for example, the coating of structured amino resin surfaces, as is customary in the manufacture of laminate or furniture panels, has been avoided.

The painted material according to the invention is characterized in that the applied layer of radiation-curing paint or paints is so thin that a structuring present in the substrate is essentially retained. According to the invention, this is made possible by the fact that, because of the vinyl functionalization, corresponding primer or undercoat layers can be dispensed with. For example, the painted material typically does not contain a paint, primer or primer layer. The radiation-curing lacquer that is applied to the vinyl-functionalized surface can therefore also directly be a top coat. Otherwise, this would only adhere to the usual amino-group-containing plastics, in particular amino resins, if they were pre-painted with appropriate paint primers or primers.

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 layer of radiation-curing paint 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 hardening varnish

Due to the vinyl groups inserted into the surface of the paintable material, it is optimally prepared for subsequent painting with a radiation-curing paint. This is because most radiation-curing paints cure themselves via vinyl-group-mediated free-radical polymerisation. The vinyl groups in the surface of the material thus represent covalent anchoring points for the radiation-curing lacquer, which leads to excellent adhesion of the lacquer to the surface of the material.

The radiation-curing lacquer can be applied to the structured surface of the lacquerable material functionalized with vinyl groups by any method known to those skilled in the art for applying lacquers. The application can take place in particular by rolling, spraying, splashing, flooding, dipping, pouring, doctor blade and / or brushing.

By selecting the radiation-curing lacquer, the desired degree of gloss and the surface properties can be set flexibly and specifically. Partial matt/gloss effects or matt/gloss gradations tailored to the decor image can also be achieved by selecting a suitable radiation-curing lacquer. The radiation-curing lacquer preferably has a gloss value of less than 10, preferably less than 5, in each case measured according to ÖNORM EN ISO 2813 (version 2015-01-01) with the 60° geometry after curing.

Radiation-curing paints are known to those skilled in the art and are described, for example, here: Prieto and None, "Wood Coating", FARBE UND LACK, 2019, Chapter 3.1.6 - Radiation-curing paint systems. A "radiation-curing lacquer", as used here, is a lacquer that contains film formers with carbon-carbon double bonds that polymerize radically under the influence of ultraviolet light (UV) or ionizing radiation (ESH). The carbon-carbon double bonds are preferably acrylic double bonds, ie those that go back to acrylic or methacrylic acid or derivatives of these compounds. at photoinitiators must be added to UV curing in order to generate the starting radicals required for polymerisation. In addition to the film-forming agent, the radiation-curing lacquer usually contains reactive diluents and photoinitiators and, if appropriate, other additives selected from the group consisting of pigments, fillers, matting agents, defoamers, silicone oils, and inhibitors or stabilizers.

According to one embodiment, the radiation-curing lacquer is a radiation-curing acylate 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 usually used in paint compositions which are used for surface finishing. Dipropylene glycol diacrylate (DPGDA) and/or poly(propylene glycol diacrylate) (PPGDA) is preferably used as the radiation-curing acrylate resin. Other radiation-curable acrylate resins that can be used according to the invention are sold, for example, by BASF under the “Laromer®” brand. If "acrylate" is mentioned here, then it always includes the corresponding methacrylate derivative.

The person skilled in the art understands reactive diluents to mean polymerizable, radiation-curing monomers which are added to the radiation-curing lacquer to reduce the viscosity. In contrast to a classic solvent, the reactive diluents react with the radiation curing in the radical polymerization and are thus incorporated into the paint film as monomers. Particularly good results can be achieved with monomeric (meth)acrylic acid esters as reactive diluents which are liquid at room temperature. Examples of such compounds are isobornyl aciylate, hydroxypropyl methacrylate, trimethylolpropaneformalmonoacrylate, tetrahydrofurfuryl acrylate, phenoxyethyl acrylate, trimethylolpropane triacylate, dipropylene glycol diacylate, tripropylene glycol diacylate, hexanediol diacrylate, pentaerythritol tetraacylate, dipentaerythritol pentaacylate, lauyl acylate, and propoxylated or ethoxylated variants of these reactivities. Urethanized reactive thinners such as EBECRYL 1039 (Cytec) or others can also be used Room temperature liquid compounds that are able to react under conditions of radical polymerization with z. Example, vinyl ether or allyl ether.

Preferred vinyl ethers are diethylene glycol divinyl ether, triethylene glycol divinyl ether or cyclohexanedimethanol divinyl ether. The radiation-curable paint can contain reactive diluents in an amount of 1-70% by weight

The film former in the radiation-curable lacquer is preferably selected from unsaturated polyesters, epoxy acrylates, polyester acrylates, polyether acrylates, amino-modified polyether acrylates and urethane acrylates. Particularly suitable unsaturated polyesters (UP) are those based on maleic acid. In practice, these are often combined with styrene as a reactive diluent.

In order to be able to be UV-cured, radiation-curable coatings must contain photoinitiators. A wavelength of 200 nm would be required for the homolytic cleavage of the C=C double bond. Commercially available UV lamps only emit to a very small extent in this contraction length range. In addition, this range of radiation is absorbed by air, creating ozone. Photoinitiators are free radical generators that are able to absorb the higher-emission, longer-wave range of the UV radiator. The radicals formed in this way then trigger the radical polymerization of the reactive components of the UV coating (film former and, if necessary, reactive diluent). Photoinitiators can be selected, for example, 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 paint contains pigments or other absorbing substances, these and the photoinitiator used must be selected and matched to one another in relation to the absorbed wavelength ranges. The invention is described below by way of example using exemplary embodiments

Described in more detail with reference to the accompanying drawings. The examples serve only to illustrate the invention and do not limit the scope. Shown in the drawings

1: a material that can be painted or painted according to the invention, which is panel-shaped and whose surface has a structure that simulates a wood grain,

Fig. 2: Cross-sections through various plate-shaped materials that can be painted according to the invention, which are intended to illustrate the structure of these materials and their surface layers, with Fig. 2a showing a laminate, Fig. 2b a laminate and Fig. 2c a wood-based material,

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 in order to lead to a vinyl functionalization of the material surface,

Fig. 4: Cross sections through various plate-shaped lacquered according to the invention

Materials, which are the materials from Fig. 2, the surface of which has been functionalized according to the invention and then painted with a radiation-curing paint,

5: Schematic representations of the structured material surface before and after painting and possibly functionalization, FIG. 5a showing a structured material surface before any functionalization or painting, FIG. 5b a surface primed or primed and then painted according to the prior art 5c a paintable material surface functionalized according to the invention with vinyl groups and FIG. 5d a functionalized surface as shown in FIG. 5c after painting, 6 shows a schematic representation of the manufacturing process for the material that can be painted or painted according to the invention.

Fig. 7: an example stylus profile to explain the used here

Roughness parameters R _z and Rt

30 infeed conveyor 1 shows a plan view of a material 1 that can be lacquered or lacquered according to the invention. In both cases, the characteristic structuring 3 of the surface can be seen (structured surface made of plastic containing amino groups or structured lacquered surface), which simulates a wood grain in the embodiment shown. The material 1 is plate-shaped and can have a decoration (eg a wood decoration) which is consistent with the structure 3 . The material 1 has a surface made of a plastic 2 containing amino groups, into which the structuring 3 is introduced.

FIG. 2 shows cross sections through three exemplary materials 1 which can be used according to the invention and which can look as shown in FIG. 1 in a plan view. The material 1 shown in FIG. 2a is a laminate of a carrier plate 5, an underlying backing 6 and an overlying top layer 4. The backing 6 is typically a paper impregnated with synthetic resin, which serves to absorb the stresses equalize on top and bottom. The support panel 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 backing 6 to form the material 1 . This connects the layers of the laminate 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 because of 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).

The structuring 3 of the surface, already shown in plan view in FIG. 1, can also be seen in cross section, which are shown here schematically as indentations, such as are produced, for example, during production with structured pressed metal sheets can become. However, it is of course also possible to apply structuring measures (e.g. 3D printing), which would then lead to elevations in the surface or a combination of elevations and depressions. The shown surface made of plastic 2 containing amino groups can already have been functionalized according to the invention with vinyl groups, 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 method according to the invention for producing the paintable material 1′.

The material 1 shown in FIG. 2b is a laminate, eg a compact board. The core 7 is formed by a stack of kraft papers impregnated with phenolic resin (eg 90 layers), the top layer 4 can again be as in FIG. 2a a melamine-resin-impregnated decorative paper and a melamine-resin-impregnated overlay lying thereover, which were hot-pressed together with the core 7 of impregnated papers to form the material 1 . What has already been said about FIG. 2a applies correspondingly to the other features.

As shown in FIG. 2 c , the material 1 can also just be a support plate 5 provided with a structure 3 . This has a surface made of a plastic 2 containing amino groups. The carrier plate 5 can consist, for example, of the plastic containing amino groups or be coated with it. The carrier board 5 can also be a wood material board (e.g. chipboard, fiber board or OSB board), which was obtained from lignocellulose-containing particles, which were glued with an aminoplastic binder and pressed to form the wood material board. The amino groups on the surface 2 are then terminally remaining primary amino groups and the secondary amino groups of the cured amino resin. The carrier plate has a structure 3 at least on the top surface 2 . What was said about FIG. 2a applies accordingly.

Fig. 3 shows schematically a detailed view of the reactions on the shown in Figs. 1 and 2 surface of an amino-containing plastic 2 at the functionalization according to the invention with the functionalization reagent 8 take place in FIG. 3a and FIG. 3c in each case a single secondary amino group (-NHR) is representatively shown in the surface of a plastic 2 containing amino groups. It goes without saying that the surface made 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 parts of the molecule: (1) a first functional group A, which has a vinyl group 9, (2) a second functional group B, which is a group that is reactive toward the amino groups of the plastic containing amino groups, and ( 3) the intervening part of the molecule, referred to herein as the "spacer" 10 . In the case of more complex molecules, the spacer length designates the shortest path between the 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 can also be present between the carbon atoms. The functionalization reagent 8 is thus at least a bifunctional molecule, since it has at least the functional groups A and B. In FIGS. 3a and 3b, the functionalization reagent 8 is shown only schematically. The functional group A shown in Figure 3a can be any functional group comprising a vinyl group 9 . Group A can also consist of a vinyl group. The functional group B shown in FIG. 3a can be any group that is reactive toward the amino groups of the plastic containing amino groups. Group B can be, for example, an epoxide,

Acid anhydride, acid chloride, acid azide, sulfonyl chloride, ketone, aldehyde, carboxylic acid, ester, especially N-hydroxysuccinimide ester, imido ester, or carbonate, carbodiimide, isocyanate, isothiocyanate, alkyl halide, allyl halide, alkyne or a vinyl group such as acylate, methacrylate or Acrylamide, act In FIGS. 3c and 3d, a specific functionalization reagent 8 is shown by way of example with hexanediol diacylate (HDDA). In this symmetrically constructed molecule, both both group A and group B are an acrylate group. The spacer 10 here consists of six -CH2- groups.

According to the invention, the functionalization reagent 8 is applied to the surface of a plastic 2 containing amino groups, resulting in the arrangement shown schematically in FIGS. 3a and 3c. By setting the appropriate reaction conditions, there is a reaction on the surface 2 between the amino groups present there and the reactive group B of the functionalization reagent 8 and thus the functionalization reagent is grafted onto an amino group on the surface of the plastic containing amino groups, forming a covalent bond 11 as in Figure 3b and 3d shown. The surface 2 was thereby covalently functionalized with vinyl groups 9, which are now available there for reaction with e.g. a radiation-curing lacquer. 3b and 3d) thus show a detailed view of the functionalized surface of a material 1' that can be painted according to the invention.

The reaction conditions, which are symbolically represented by a reaction arrow between FIGS. 3a and 3b or 3c and 3d, depend strongly on the nature and chemistry of the reactive group B in the functionalization reagent. If the reactive group B is a vinyl group and in particular an acrylate group, exposure to high-energy radiation such as electron beams or UV light is sufficient for the aza-Michael addition shown in FIGS. 3c and 3d to occur.

The material surfaces functionalized with vinyl groups can then be painted or stored. If a non-reversible reaction is selected for the functionalization (e.g. aza-Michael addition), the material surfaces functionalized with vinyl groups have proven to have a good shelf life. However, it also has advantages to further process the functionalized material surfaces directly, in particular to paint them, since excess functionalization reagent is not disruptive and, on the contrary, can polymerize directly into the paint layer. When storing, it is recommended to avoid contamination or des Take precautions against smearing such as single sheet storage, storage with interleaving, or cleaning up the excess. According to a preferred embodiment, the functionalization with vinyl groups is immediately followed by a coating of the functionalized material surface.

If you paint directly, it doesn't bother you, because the reagent polymerizes in. 4a-4c show the materials already discussed in connection with FIGS. 2a-2c, but this time after vinyl functionalization according to the invention and subsequent painting. On the (not shown) with vinyl group-functional top layer 4 is now a layer of strahlenhärtendem coating 12. It can, for example, a commercially available acrylate applied directly to an inventive functionalized structured melamine resin surface covering lacquer in a layer thickness of 5-15 g / m ² will. Due to the fact that primer or base coats can be dispensed with according to the invention, the paint layer 12 can be applied so thinly that the structure 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 - 4c after painting). It is thus possible, for example, structured

Amino resin surfaces, as shown schematically in Fig. 1 in plan view, to obtain in painted form. The inventors have surprisingly found that if you combine such a surface structure 3 with a matt paint 12 or an excimer hardening of the paint layer 12, you create natural-looking material surfaces that look, feel and feel like the original (e.g. real wood parquet) so well are no longer distinguishable and at the same time have improved surface properties (e.g. resistance to micro-scratches, weathering and chemicals).

FIG. 5 serves to illustrate the advantages of the invention over the prior art. FIG. 5a shows an enlargement of the cross section through the uppermost layer 4, as can also be seen, for example, in FIGS. 2a-2c. The top layer 4 has a structure 3 and consists of or contains a plastic containing amino groups (eg a melamine resin), whereby it has a Surface made of plastic containing amino groups 2 has. If you wanted to paint such a melamine resin surface according to the prior art with a radiation-curing paint 12 (e.g. an acrylate paint), you would first have to apply a primer layer 13 to the structured melamine resin surface, since radiation-curing paints only adhere very poorly to this. The multi-layer paint structure 12, 13 results in a considerable paint layer thickness--in comparison to the largest difference in height and depth in the structure 3 (Rz value). The structuring is lost due to the overcoating. According to the state of the art, it therefore makes no sense to paint over, for example, a melamine resin surface provided with a wood structure (cf. FIG. 1), such as is often used, for example, as a furniture surface or floor laminate. Such a coating would destroy an originally introduced structuring.

By contrast, the invention makes it possible to coat over structured amino 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 uppermost layer 4, as can also be seen, for example, in FIGS. 2a-2c. As in FIG. 5a, the uppermost layer 4 in FIG. 5c also has a surface made of plastic 2 containing amino groups, into which a structure 3 has been inserted. As is clear from a comparison of FIG. 5a with 5c, the material 1' which can be painted according to the invention in FIG. 5c has a surface functionalized with vinyl groups 9 (see also FIGS. 3b and 3d). As shown in FIG. 5d, a layer of radiation-curing lacquer 12 can be applied directly to this surface functionalized according to the invention with vinyl groups 9, without a primer layer 13 having to be applied beforehand. 5d shows the applied layer of radiation-curing lacquer before radiation-curing, as can be seen from the vinyl groups 9 that are still present. During the radiation-induced free-radical polymerization of the paint layer 12, the vinyl groups 9 present on the surface 2 also polymerize into the paint film, which is covalently anchored in the uppermost layer 4 of the material. This explains the observed excellent adhesion of radiation-curing paints to the paintable material surfaces provided by the invention. Since the vinyl groups 9 introduced into the surface 2 react in the lacquer during the radiation curing, they are no longer detectable after the lacquer layer 12 has been cured by radiation. In cross-section, therefore, a material painted according to the invention simply appears as if no primer or undercoat layer had been used. Only the paint film itself can be seen on the substrate.

In contrast to the prior 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 realized if the primer or base coat layer is omitted. 5d therefore shows the structured lacquer layer present in the material lacquered according to the invention, which corresponds to the structuring of the material surface before lacquering (compare FIG. 5a or 5c with FIG. 5d).

6 shows, by way of example, a system and a method for producing a material that can be painted according to the invention, which is then further processed directly into the material painted according to the invention. A first, second and third feed conveyor belt 14, 15, 16 is used to feed a wood-based panel as a carrier 5 with a backing 6 on the underside (shown as a liquid backing applied on the underside, the latter can also be fed in via a separate fourth feed conveyor belt) and a melamine-resin-impregnated decorative paper 18 and melamine-resin-impregnated overlay 19 placed on a feed conveyor belt 30 as a press stack 20. For the sake of simplicity, the feed conveyor belt 30 is drawn as a continuous conveyor belt. In practice, however, there are several separate conveyor belts whose speeds and surface properties are adapted to the respective process step. The press stack 20 then runs 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 wood grain shown in FIG Compression pressure (active pressure on the panel surface) of 50 to 300 N/cm ^{2 is} pressed to form the material 1, which is a laminate panel which has a surface 2 containing a structure 3 containing amino groups. Both terminal primary amino groups and secondary amino groups are present on the surface 2 in the cured melamine resin. The material 1 corresponds to a material known from the prior art with a structured surface, as is produced in many variations as a floor covering or furniture component and is already present in interim storage facilities.

The production of the material 1 is therefore only shown in the upper part of FIG. 6 for the sake of completeness. Material 1 can be stored and the process can be interrupted here. Above all, in practice the numerous materials 1 already available with structured surfaces 2, 3 containing amino groups can be used. These can be fed to the process according to the invention for surface functionalization with subsequent painting without pretreatment. This is another advantage of the solution according to the invention.

The material 1 with a structured surface 2, 3 containing amino groups is fed to a device 23 for applying the functionalization reagent 8 according to the invention. In the embodiment shown, a functionalization reagent having 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 surface 2 containing amino groups,

3 of the material 1 applied. In Fig. 6 the application of the

Functionalization reagent 8 shown in the device 23 as spraying. However, numerous alternative application methods are also possible, as explained in the description, in particular application via a roller as shown in FIG. 6 for the device for applying the radiation-curing lacquer 26 .

In the next step, the applied functionalizing reagent 8 is brought into reaction 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 with the amino groups on the material surface is a vinyl group, especially one that is adjacent to an electron-withdrawing group (such as in an acylate group), the reaction can take the form of a radiation-induced aza-Michael addition respectively.

The surface 2 of the material 1 containing amino groups, to which the functionalization reagent 8 has been added, is exposed to a radiation source 24 for this purpose. The high-energy radiation 25 (e.g. UV or electron beams) hits the surface 2 and leads there 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 hereby grafted onto the surface 2 of the material, which leads to a covalent functionalization of the surface 2 with vinyl groups. The material 1' functionalized in this way represents the paintable material of the invention.

The paintable material 1' can be painted with a radiation-curing paint 12 directly afterwards or in a separate process. For this purpose, the material 1′ runs through a device 26 for applying the radiation-curing lacquer 12. FIG. 6 shows the application of the lacquer in device 26 by a roller, but all methods for applying radiation-curing lacquers otherwise known to those skilled in the art 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 system shown in Fig. 6, in addition to the second radiation source 29 actually required for curing (e.g. a UV lamp or an electron emitter) an upstream excimer radiation source 27 is provided. In this, the applied paint layer is exposed to excimer radiation 28 (172 nm), which results in the microstructuring of the paint surface, which is explained in more detail in the description. The painted material 1" thus obtained not only has a macroscopically structured paint surface which corresponds to the surface structure 3 present in the paintable material (e.g wood grain, see top view in Fig. 1), but also a microstructuring that causes a special matting and also gives the surface of the material 1" anti-fingerprint properties.

FIG. 7 shows a diagram which illustrates the determination of the characteristic values Rz, Rz Max and Rt measured according to DIN EN ISO 4287. Rz means: mean difference from highest and lowest profile (average of the five shown Rz values 1 to 5); Rz Max: highest point measured (largest Rz value determined); Rt: total height of the profile (distance between the highest peak and the lowest valley of the profile over the entire length ln evaluated).

Industrially manufactured laminate flooring or furniture surface panels with a structured melamine resin surface from the EGGER company were used in all of the exemplary embodiments. These were CPL panels with the following layer structure: balancing sheet, MDF core, melamine resin-impregnated decor and overlay paper, with the following structures being embossed into the latter during pressing using appropriately designed pressing plates:

ST67 F870 slate decor paper, trade name "CERAMIC", with an irregular rough character (all-over structure/no synchronous structure)

ST69 "Natural Pore" decorative paper - authentic, true-to-decor wood grain in

Combination with surface structure ST28 "Gladstone Oak" decor paper (look of classic planked oak) running synchronously to this, in

Combination with the surface structure ST28 Feelwood Nature (haptics of sandblasted oak) that runs synchronously with it.

Fl wood grain in all-over structure test series 1

As indicated in the table below, the textured 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/m 2} hexanediol diacrylate (HDDA) was applied by roller application and then treated with a UV Lamp irradiated (Examples 2, 7 and 10 according to the invention; was irradiated with an 80 watt mercury lamp, with 10 m / min advance with the dose of UV-A> 350 mj / cm ² ) or it was a commercial UV primer for Melamine resin surfaces (1CA UVF5782) applied in an amount of 4 or 4-5 g/m ² by roller application and gelled by UV irradiation (Comparative Examples 4,

6 and 9; was also irradiated with an 80 watt mercury lamp, with a feed rate of 10 m/min with a dose of UV-A >350 mj/cm ² ). The surfaces vinyl-functionalized according to the invention with HDDA or primed according to the prior art were then coated with commercially available UV topcoat compositions (acylate lacquer, 1CA UVS5595) and UV-cured according to the manufacturer's instructions. For this purpose, after the application of the top coat, excimer was first cured at 15 m/min (from IST) followed by double irradiation with a 120 W mercury lamp for final curing.

The gloss value below 60° and 85° was determined according to ÖNORM EN ISO 2813 (Version 2015-01-01). The surface quality was also determined using the profile method according to DIN EN ISO 4287 (October 1998 version). The definition of the Rz value is as given in the description and in FIG.

Adhesion was determined using the "Hamberger Hobel", a standardized test device from Hamberger Industriewerke, which can be used to carry out a coin test under defined conditions. A piece of metal with a coin-like edge is pushed over the painted surface with adjustable pressure. The result is the force in Newtons at which no stress whitening is discernible. All Results above 15 Newtons can generally be regarded as acceptable.

The following test results were obtained:

Table 2

* Not according to the invention (starting product, structured melamine resin surface) ** Not according to the invention (coated with UV primer and UV varnish)

A comparison of Samples 1* and 2 shows that, with the functionalization according to the invention, it is possible to apply a UV lacquer directly to a melamine resin surface without the adhesive bond deteriorating

(Hamberger planer coin test). By using a matt UV varnish, the unnaturally high-gloss melamine resin surface can be given a matt appearance (gloss 60° at approx. 3, cf. Examples 2, 7 and 10 according to the invention with the corresponding melamine resin surfaces 1*, 5* and 8*) and nevertheless their structured surface matching the decor is retained or even intensified (difference [D] in the Rz values unchanged to positive in Examples 2, 7 and 10 according to the invention). In contrast to this, the application of a layer of standard UV primer with subsequent painting results in even the relatively thin layer thicknesses used (up to 10 g/m² for UV primers and up to 15 ^{g/m 2 for top coats are usual).} g/m ² ) resulted in a sharp decrease in the Rz value after painting (see negative difference [D] of the Rz values in Comparative Examples 4**, 6** and 9**).

In addition, the micro-scratch resistance of the surfaces was determined in accordance with DIN EN 16094 (Martin Dale standard for floors).

(Rating 1 - 5; 1 best rating, 5 worst rating)

While the unpainted melamine resin surfaces were very susceptible to micro-scratches, the micro-scratch resistance could be increased significantly by the coating according to the invention, while retaining the structure originally present.

Samples 1 to 10 were also assessed in a blind test by trained specialists from EGGER. This assessment showed that samples 2, 7 and 10 according to the invention had by far the most natural appearance of all 10 samples and in terms of their appearance, haptics and touch temperature they hardly differed from the original to be imitated (veneer/real wood surface, stone/ceramic decors or textile decor image with a smooth structure) could be distinguished.

test series 2

Similar results as with the UV primer 1CA UVF5782 and top coat 1CA 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 top coats (tested: Plantag 75773.6, Teknos E120239, Bergolin 2U073, Bona 7720, Akzo Nobel UV TOP 103939). 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 3

A test series was carried out as described for test series 1, except that BDDA was used as the functionalization reagent instead of HDDA. The results were similar to those of 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 4

A test series was carried out as described for test series 1, except that DPGDA was used as the functionalization reagent instead of HDDA. The results were similar to those of 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

A test series was carried out as described for test series 1, except that TMPTA was used as the functionalization reagent instead of HDDA. The results were similar to those of 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

In a manner analogous to that described for test series 1, a furniture surface decor H3399 with the structure ST28 (raw sample) was functionalized with HDDA (1 g/m ² ). Instead, a commercially available UV primer (Plantag Primer 74170.5) was used in an application quantity of 4 g/m ² for the comparative example. According to the technical data sheet, this contains: Propylidyntrimethanol, ethoxylated, ester with acrylic acid; 2-ethylhexyl acylate and 2-hydroxy-3-phenoxypropyl acylate. In both cases, a UV varnish from Plantag 78700.1 (8 g/m ² ) was applied as the top varnish. According to the technical data sheet, this contains: 1,6-hexanediol diacylate, acrylic resin and methyl benzoyl formate. In contrast to test series 1, however, no excimer curing took place. The following results were obtained:

Example 2:

In a manner analogous to that described for test series 1, a floor panel with wood decor H1007 “Parquet Oak” and a flatter structure as a surface was functionalized with DPGDA (amount applied 1.5 g/m ² ). Instead, a commercially available UV primer (UVILUX Primer 621-183) was used in an application quantity of 4 g/m ² for the comparative example. According to the technical data sheet, this contains: exol-l,7,7-trimethylbicyclo[2.2.1]hept-2-yl acrylate, dipropylene glycol diacylate, 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 paint, applied quantity 8 g/m ² ) was applied as the topcoat and cured with excimer as described in test series 1. The following results were obtained:

Example 3 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 as a surface with 0.5 g/m ² TMPTA. Instead, a commercially available UV primer (Bergolin 1U080) was used in an application amount of 4 g/m ² for the comparative example. According to the technical data sheet, this contains: 4-(l,l-

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

Aciylateharz, 11 g / m ² ) used and as described in test series 1 cured with excimer. According to the technical data sheet, the top coat 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-piperidylsebazate and 1,1,1-trihydroxymethylpropyl triacrylate. The following results were obtained: As a comparison of the Rt values for Examples 1 to 3 shows, the structure is always best preserved in the coating of the invention. Surfaces coated according to the invention have similarly good Hamberger Plane results as the melamine resin starting surfaces (raw samples), but achieve similarly good values in the Martin Dale test as melamine resin surfaces coated over with UV coating.

Claims

patent claims

1. Paintable material with a surface made of a plastic containing amino groups, characterized in that the surface is structured and that 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 on a functionalizing reagent.

2. Paintable material according to claim 1, characterized in that the functionalization reagent has at least one vinyl group and at least one group which is reactive towards the amino groups of the plastic containing amino groups.

3. Paintable material according to claim 1 or 2, characterized in that the functionalization reagent has a molecular weight of 90 to 2000, preferably 95 to 1100 and particularly preferably 95 to 600.

4. Paintable material according to one of the preceding claims, characterized in that the further group in the functionalization reagent which is reactive towards the amino groups of the plastic containing amino groups 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.

5. Paintable material according to one of the preceding claims, characterized in that the further group in the functionalization reagent which is reactive towards the amino groups of the plastic containing amino groups is also a vinyl group.

6. Paintable material according to one of the preceding claims, characterized in that the grafting involves the application of 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 on the structured surface of the plastic containing amino groups and the subsequent heating or irradiation with UV or electron beams.

7. Paintable material according to claim 4 or 5, characterized in that the functionalization reagent is selected from the group consisting of di-, tri-, tetra-, penta- or even higher-functional acylates, methacylates, vinyl ethers and allyl ethers, the functionalization reagent being selected in particular may be from the group consisting of trimethylolpropane triacylate, dipropylene glycol diacrylate, tripropylene glycol diacrylate, hexanediol diacrylate, pentaerythritol tetraacrylate, dipentaerythritol pentaacrylate, dipentaerythritol hexaacylate

Neopentyl glycol diacrylate, and propoxylated or ethoxylated variants of these compounds, polyalkylene glycol diacylates, in particular polyethylene glycol diacrylates, divinyl ethers, in particular diethylene glycol divinyl ether, triethylene glycol divinyl ether or cyclohexanedimethanol divinyl ether, and diallyl ether.

8. Paintable material according to one of the preceding claims, characterized in that the vinyl groups in the material surface and/or in the functionalization reagent are selected from the group consisting of acylates, methacrylates, vinyl ethers, allyl ethers and vinylaromatic compounds, the latter being able to be selected in particular from styrene , Ci-4-alkyl-substituted styrene, stilbene, vinylbenzyldimethylamine, (4-vinylbenzyl)dimethylaminoethyl ether, N,N-dimethylaminoethylstyrene, tert-butoxystyrene and vinylpyridine.

9. Paintable material according to one of the preceding claims, characterized in that the plastic containing amino groups is selected from the group consisting of amino resins, aminopolysiloxanes, polyvinylamines, polyalkyleneimines, aminoepoxide resins and polyurethanes with terminal amino groups.

10. Paintable material according to claim 9, characterized in that the plastic containing amino groups is an amino resin, in particular a melamine-formaldehyde resin or a melamine-urea-formaldehyde resin.

11. Paintable material according to one of the preceding claims, characterized in that the material is a sheet-like or plate-like material, in particular a wood-based panel; a support 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.

12. Painted material with a textured paint finish available from:

(a) providing a paintable material according to any one of claims 1 to 11, (b) applying a layer of a radiation-curing paint to the vinyl-modified, structured plastic surface of the material, (c) radiation-curing of the paint layer.

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

14. Painted material according to claim 12 or 13, characterized in that the total amount of radiation-curing paint 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 .

15. Painted material according to one of claims 12 to 14, characterized in that the paint layer is an excimer-hardened paint layer and/or has a gloss value of less than 10, preferably less than 5, measured in each case according to EN ISO 2813 with the 60° geometry, having.

16. Paintable material according to one of claims 1 to 11 or painted material according to one of claims 12 to 15, 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.

17. Paintable material or painted material according to claim 16, characterized in that 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 shows the surface structure of wood, natural stone, engineered stone, ceramic, metal, mosaic, plank, tile, grout or any other decorative structure visible to the naked eye.

18. A method for producing a paintable material according to any one of claims 1 to 11 comprising the following steps: c) providing a material with a structured surface made of a plastic containing amino groups, d) covalent functionalization of the structured surface with vinyl groups (i) bringing the structured surface into contact with a functionalizing agent which has at least one vinyl group and at least one other group which is 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.

19. A method for producing a painted material with a structured paint surface according to any one of claims 12 to 17, comprising the following steps: a) carrying out a method according to claim 18 or providing a paintable material according to any one of claims 1 to 11, b) applying a layer a radiation-curing lacquer on the structured surface of the material functionalized with vinyl groups, c) radiation-curing of the lacquer layer.

20. Use of a vinyl functionalization as a substitute for a primer layer or primer when coating structured surfaces made of plastic containing amino groups with radiation-curing coatings.