EP1526923A2 - Radiation-curable paint systems having a lower layer with low-temperature elasticity - Google Patents

Abstract

A multicoat system on a substrate, comprising at least one radiation-curable coating system (F) and at least one elastic intercoat (D) which is located between substrate and radiation-curable coating system (F) and has a glass transition temperature (Tg) of −20° C. or less.

Description

Radiation-curable coating systems with low-temperature elastic underlayer

description

The present invention relates to a method for improving the fracture mechanical properties of highly scratch-resistant radiation-curable lacquer systems, lacquers obtainable by this method and the use of such lacquers.

A high scratch resistance is a widespread requirement for paints. In the automotive industry, for example, plastic parts are coated with a scratch-resistant clear lacquer, which can be thermally curing, so-called one- or two-component PU lacquers, or, preferably, clear lacquers that are exposed to actinic radiation Harden radiation. With hard coatings, however, the problem frequently arises that a microcrack initiated in the coating propagates in a very locally defined manner through the coating into the substrate to which the coating is applied, as it e.g. is described in DE-Al 199 56 483.

DE-Al 199 56 483 describes coated plastic molded parts which, on a plastic layer made of at least one graft polymer made of a rubber-elastic graft base with a glass transition temperature T _g below 10 ° C and a graft cover with a T _g of more than 30 ° C, determine at least one coating Have properties. A rubber phase is thus distributed in the substrate.

A disadvantage of the process described is that such graft polymers can only insufficiently bind covalently to the topcoat, since grafting can only be carried out by breaking the volume of the elastomeric component of the blend. In particular, for a highly break-proof paint build-up, it is important to prevent small micro cracks from spreading by means of a continuous layer of elastomer. DE-Al 199 20 801 describes special multilayer clearcoats in which each clearcoat layer is radiation-curable, one layer being made scratch-resistant by inorganic nanoparticles.

DE-Al 100 27 268 describes special multilayer clearcoats in which curing in one step by means of thermal crosslinking of polyols based on acrylate copolymers Triazine crosslinker takes place, this can be done simultaneously or in succession.

WO 99/26732 describes a method for producing a multi-layer coating, in which a coating agent and a clear lacquer layer are applied to an optionally precoated substrate.

A disadvantage of these cited documents is that even when the technical teaching disclosed there is applied, the scratch resistance, in particular the problem of cracking in the lacquer, is unable to meet today's requirements.

The object was therefore to develop a coating which has a very high scratch resistance with good adhesion to the substrate and at the same time reduced crack propagation into the substrate.

The object was achieved by a multi-layer coating on a substrate containing at least one radiation-curable coating system (F) and at least one elastic intermediate layer (D) between the substrate and radiation-curable coating system (F) with a glass transition temperature (T _g ) of -20 ° C or lower (measured in the frequency range up to 1000 Hz).

A crack formed in a multilayer coating according to the invention in an external coating system (F) does not propagate through the elastic intermediate layer (D) under typical loads in the uses described, so that the substrate to which the multilayer coating is applied is not damaged and maintains its characteristic mechanical properties.

Such a multi-layer coating according to the invention can contain further layers. For example, a multilayer coating according to the invention consists of the following layers, which can typically be arranged as follows:

(F) at least one radiation-curable coating system, (E) optionally at least one pigmented and / or layer provided with effect substances, (D) at least one elastic intermediate layer (D) with a

Glass transition temperature (T _g ) of -20 ° C or lower, (C) optionally at least one layer selected from the group consisting of primer, basecoat, primer, pigmented or effect paint and substrate 2, (B) optionally at least one elastic intermediate layer, if layer (C) is a substrate 2 and (A) substrate 1 with a toughness according to DIN EN ISO 179 / lfu at 23 ° C and 50% humidity of at least 20 kJ / m.

The structure of such a multi-layer coating is generally in the order given, so that the substrate 1 (A) is located below, as agreed, the radiation-curable coating system (F) above and the elastic intermediate layer (D) in between.

Substrates 1 and / or 2 in layers (A) and / or (C) can be, for example, wood, wood veneer, paper, cardboard, cardboard, textile, leather, fleece, plastic surfaces, metals or coated metals, paper is preferred, Plastics or metals, particularly preferred are plastics / and very particularly preferably transparent plastics.

In this context, plastics are understood to be the technical plastics known per se to the person skilled in the art with toughnesses according to. DIN EN ISO 179 / lfU at 23 ° C and 50% humidity of at least 20, preferably at least 25 kJ / m ² , for example polymers and copolymers, the (meth) acrylic acid esters, vinyl aromatic compounds, for example styrene, divinylbenzene, vinyl esters, for example vinyl acetate, halogenated ethylenically unsaturated compounds, for example vinyl chloride,

Vinylidene chloride, conjugated unsaturated compounds e.g. Butadiene, isoprene, chloroprene, α, β-unsaturated nitriles, e.g. Acrylonitrile, monounsaturated compounds, e.g. Ethylene, propylene, 1-butene, 2-butene, isobutene, cyclic monounsaturated compounds, e.g. Cyclopentene, cyclohexene, N-vinylpyrrolidone, N-vinyllactarne, such as e.g. N-vinyl caprolactam, vinyl ether, e.g. Contain methyl vinyl ether, ethyl vinyl ether, n-propyl vinyl ether, isopropyl inyl ether, n-butyl vinyl ether in copolymerized form.

Polyethylene, polypropylene, polystyrene, polybutadiene, polyester, polyamides, polyethers, polyvinyl chloride, polycarbonate, polyvinyl acetal, polyacrylonitrile, polyacetal, polyvinyl alcohol, polyvinyl acetate, phenolic resins, urea resins, melamine resins, alkyd resins, epoxy resins or polyurethanes, their block, may be mentioned by name Graft copolymers and blends thereof.

ABS, AES, AMMA, ASA, EP, EPS, EVA, EVAL, HDPE, LDPE, MABS, MBS, MF, PA, PA6, PA66, PAN, PB, PBT, PBTP, PC, PE, PEC, PEEK may be mentioned in particular , PEI, PEK, PEP, PES, PET, PETP, PF, PI, PIB, PMMA, POM, PP, PPS, PS, PSU, PUR, PVAC, PVAL, PVC, PVDC, PVP, SAN, SB, SMS, UF, UP plastics (abbreviation according to DIN 7728) and aliphatic polyketones.

The plastics mentioned can preferably also be coronized. The substrates can optionally be pigmented or unpigmented.

Preferred substrates are polyolefins, e.g. PP (polypropylene), which can be optionally isotactic, syndiotactic or atactic and optionally non-oriented or oriented by uni- or bisaxial stretching, SAN (styrene-acrylonitrile copolymers), PC (polycarbonates), PMMA (polymethyl methacrylate), PBT (poly (butylene terephthalate) e), PA (polyamides), ASA (acrylonitrile-styrene-acrylic ester copolymers) and ABS (acrylonitrile-butadiene-styrene copolymers), as well as their physical mixtures (blends). PP, SAN, ABS, ASA and blends of ABS or ASA with PA or PBT or PC are particularly preferred.

Substrates 1 in layer (A) can also be identical or different, laminated substrates, for example laminated plastics.

The substrates 1 and 2 in the layers (A) and (C) can be the same or different.

One or more substrates 1 and / or 2 may be present in the layers (A) and / or (C), for example 1 to 3, preferably 1 to 2 and particularly preferably one.

If layer (C) contains at least one substrate 2, it can preferably be a film, for example a plastic or metal or particularly preferably a plastic film, which can be made from the specified plastics.

Such a film can have a thickness of 1 μm to 2 mm, preferably 5 μm to 1000 μm, particularly preferably 5 μm to 750 μm, very particularly preferably 10 μm to 500 μm and in particular 25 μm to 300 μm.

If layer (C) contains a substrate 2, this can usefully be connected to the substrate (A) with a further elastic intermediate layer (B). Such an intermediate layer has the same features as the intermediate layer (D) (see below) and can be different or the same.

Typical thicknesses of the layer (B) range from 0.1 to 1000 μm, preferably 0.5 to 500 μm, particularly preferably from 1 to 250 μm and very particularly preferably from 1 to 100 μm.

One or more elastic connections can be used in the layer (B), for example 1 to 3, preferably 1 to 2 and particularly preferably one.

Layer (C) can contain, for example, at least one primer, basecoat, primer, pigmented or lacquered with effect substances, and / or optionally at least one substrate 2, which has already been described above.

Basically, all lacquers which are customary for these purposes and are known to the person skilled in the art are suitable as color and / or effect lacquers in the layer (C) and / or (E). These can be curable physically, thermally, with actinic radiation or thermally and with actinic radiation (dual-cure). They can be conventional basecoats, waterborne basecoats, essentially solvent-free, solvent-free and water-free liquid basecoats (100% systems), essentially solvent-free and water-free solid basecoats (pigmented powder coatings) or essentially solvent-free pigmented powder coating dispersions (powder slurry basecoats) act. They can be thermally or DualCure-curable, and self- or externally cross-linking.

These can be one or more, preferably 1 to 3, particularly preferably 1 to 2 and very particularly preferably a color and / or effect paint.

For the purposes of the present invention, essentially solvent-free means that the coating material in question has a residual volatile solvent content of <2.0% by weight, preferably <1.5% by weight and particularly preferably <1.0% by weight , It is particularly advantageous if the residual content is below the gas chromatographic detection limit.

Water-based paints such as those described in patent applications EP 0 089 497 AI, EP 0 256 540 AI, EP 0 260 447 AI, EP 0 297 576 AI, WO 96/12747, EP 0 523 610 are particularly preferably used in the multi-layer coatings of the invention AI, EP 0 228 003 AI, EP 0 397 806 AI, EP 0 574 417 AI, EP 0 531 510 AI, EP 0 581211 AI, EP 0 708 788 AI, EP 0 593 454 AI, DE-A-43 28 092 AI, EP 0 299 148 AI, EP 0 394 737 AI, EP 0 590 484 AI, EP 0 234 362 AI, EP 0 234 361 AI, EP 0 543 817 AI, W095 / 14721, EP 0 521 928 Al, EP 0 522 420 AI, EP 0 522 419 AI, EP 0 649 865 AI, EP 0 536 712 AI, EP 0 596 460 AI, EP 0 596 461 AI, EP 0 584 818 AI, EP 0 669 356 AI, EP 0 669 356 AI, EP 0 634 431 AI, EP 0 678 536 AI, EP 0 354 261 AI, EP 0 424 705 AI, WO 97/49745, WO 97/49747, EP 0 401 565 AI or EP 0 817 684, column 5, lines 31 to 45, are known are.

The color and / or effect varnishes described above can be used not only for the production of color and / or effect basecoats, but also for color and / or effect combination effect layers. In the context of the present invention, this is to be understood as a coating which fulfills at least two functions in a coloring and / or effect-giving multi-layer coating. Functions of this type are in particular protection against corrosion, the imparting of adhesion, the absorption of mechanical energy and the coloring and / or effect. Above all, the combination effect layer serves the absorption of mechanical energy and the coloring and / or effect at the same time; it therefore fulfills the functions of a filler paint or stone chip protection primer and a base coat. The combination effect layer preferably also has an anti-corrosion effect and / or an adhesion-promoting effect.

Typical thicknesses of the layer (C) and / or (E) range from 0.1 to 2000 μm, preferably 0.5 to 1000 μm, particularly preferably from 1 to 500 μm, very particularly preferably from 1 to 250 μm and in particular from 10 up to 100 μm.

The lacquers which can be used in the multi-layer lacquer coating according to the invention can contain coloring and / or effect pigments. All paint-typical pigments of organic or inorganic nature are suitable as color pigments. Examples of inorganic or organic color pigments are titanium dioxide, micronized titanium dioxide, iron oxide pigments, carbon black, azo pigments, phthalocyanine pigments, quinacridone and pyrrolopyrrole pigments.

The effect pigments are particularly characterized by a platelet-like structure. Examples of effect pigments are: metal pigments, for example made of aluminum, copper or other metals; Interference pigments, such as metal oxide-coated metal pigments, for example titanium dioxide-coated or mixed oxide-coated aluminum, coated mica, such as titanium dioxide-coated mica and graphite effect pigments. UV-curable pigments and, if appropriate, also fillers can advantageously be used, for example to improve the hardness. These are radiation-curable compounds, eg acrylic functional silanes, coated pigments / fillers, which can thus be included in the radiation hardening process.

According to the invention, the intermediate layer (D) contains at least one compound with a glass transition temperature (T _g ) of in each case -20 ° C. or lower, preferably - 30 ° C. or lower, particularly preferably -40 ° C. or lower, very particularly preferably -50 ° C or lower and especially -60 ° C or lower.

The glass transition temperature Tg was determined using bending vibration tests (in accordance with DIN 53440 Tl to T3) at a frequency of 0 to 1000 Hz, preferably 100 to 1000 Hz. The bending vibration delivers the Tg that is important from a fracture mechanics point of view at high deformation speeds (frequencies).

The thickness ZS of the intermediate layer (D) contained in the multilayer coating according to the invention can be, for example, from 0.1 to 1000 μm, preferably 0.5 to 500 μm, particularly preferably from 1 to 250 μm, very particularly preferably from 5 to 50 μm and in particular from 10 to 50 μm.

Examples of compounds which can be used in the elastic intermediate layer are rubber-containing polymers, ac-resins, polyacrylates with a T _g as indicated and poly-isobutylene. Examples of suitable rubber-containing polymers are thermoplastic elastomers. Such thermoplastic elastomers generally contain at least one elastomeric component (soft domain) and at least one thermoplastic component (hard domain), which can be joined together as a blend, vulcanizate or block polymer, preferably as a block polymer.

The elastomeric component can be styrene-butadiene (SBR), polyisoprene (IR), polybutadiene (BR), chloroprene (CR) acrylonitrile-butadiene (NBR), butyl (isobutene / isoprene) copolymer, IIR), butyl / α-methylstyrene terpolymer, ethylene / propylene (EPM), ethylene / propylene / diene (EPDM), epichlorohydrin (CO), epichlorohydrin / ethylene oxide (ECO) or ethylene / vinyl acetate rubber ( EVA / EVM) act, preferably polybutadiene, polyisoprene, ethylene / propylene or ethylene / propylene / diene rubber, particularly preferably polybutadiene or polyisoprene rubber and very particularly preferably polybutadiene rubber.

The elastomeric component (in a block polymer based on the block) generally has molar masses of at least 80,000 g / mol, preferably at least 100,000, particularly preferably 100,000 up to 250,000 and very particularly preferably 120,000 to 230,000 g / mol.

The thermoplastic component can be, for example, polypropylene, preferably isotactic polypropylene, a random or block copolymer of propylene and ethylene, HDPE, LDPE, LLDPE, EVA, ethylene / methacrylate copolymers, ethylene / ethyl acrylate copolymers, SAN, ABS, Trade ASA, PMMA or polystyrene, polystyrene and polypropylene are preferred, and polystyrene is particularly preferred.

The thermoplastic component (in a block polymer based on the block) generally has molar masses of up to 50,000 g / mol, preferably 5,000 to 40,000 and particularly preferably 6,000 to 20,000 g / mol.

As a rule, the proportion of the thermoplastic component in the total thermoplastic elastomer is up to 50% by weight, preferably up to 40 and particularly preferably up to 35% by weight. The minimum content of thermoplastic component is generally at least 8% by weight, preferably at least 20 and particularly preferably at least 25% by weight.

Preferred thermoplastic elastomers are those with at least one elastomeric block Y and at least one thermoplastic block Z of the general form Z (-YZ) m, where m is a positive integer from 1 to 10, preferably 1 to 5, particularly preferably 1 to 3, whole particularly preferably 1 or 2 and in particular 1 means. In the latter case, one speaks of so-called triblock polymers. For example, the polymers can be linear or branched, e.g. be star-shaped, preferably linear.

Particularly preferred thermoplastic elastomers are styrene oligoblock polymers, very particularly preferred are styrene triblock polymers in which the thermoplastic block consists predominantly, preferably completely, of styrene. So-called styrene-butadiene-styrene (SBS), styrene-isoprene-styrene (SIS), styrene-ethylene / butylene-styrene (SEBS) and styrene-ethylene / propylene-styrene (SEPS) block polymers, which may also be used, are particularly preferred reactive comonomers such as Maleic anhydride can be functionalized. The thermoplastic elastomers can also be completely or partially hydrogenated.

The thermoplastic elastomers which can be used according to the invention can also contain a so-called diblock fraction (ZY-) m, which is preferably up to 50% by weight, particularly preferably up to 40, very particularly preferably up to 30% by weight and in particular up to 20% by weight.

Mineral oil, polystyrene, polyolefins, fillers or additives such as antioxidants, UV stabilizers or antiozonants can also be added to the thermoplastic elastomers which can be used according to the invention.

The Kraton® brands from Kraton Polymers U.S. are very particularly preferred as thermoplastic elastomers. LLC, Houston, Texas, USA and Vector® trademarks from Dexco Polymer, Houston, Texas, USA. Particularly preferred are the Kraton D and G brands, preferably the Kraton D brands and particularly preferably Kraton D1101, D1118, D4150, D1112, D-KS 225 ES, D1102, D1116, D1186 and D4123, as well as the vector Brands 7400, 8508 and 2518.

Suitable polyacrylates are (co) polymers with a T _g as indicated.

These are usually composed as follows:

Main monomer 50 - 98% by weight secondary monomer 10 - 40% by weight functionalized monomer 0 - 20% by weight,

with the proviso that the sum is always 100% by weight.

Main monomers therein are, for example, (meth) acrylic acid methyl ester, (meth) acrylic acid ethyl ester, (meth) acrylic acid n-propyl ester, (meth) acrylic acid n-butyl ester, (meth) acrylic acid iso-butyl ester, (meth) acrylic acid seJ butyl ester, (meth) acrylic acid n-pentyl ester, (meth) acrylic acid isopentyl ester, (meth) acrylic acid 2-methyl butyl ester, (meth) acrylic acid amyl ester, (meth) acrylic acid n - Hexyl ester, (meth) acrylic acid-2-ethyl butyl ester, (meth) acrylic acid pentyl ester, (meth) acrylic acid n-heptyl ester, (meth) acrylic acid n-octyl ester, (meth) acrylic acid 2-ethyl hexyl ester, (meth) acrylic acid - n-decyl ester, (meth) acrylic acid undecyl ester, (meth) acrylic acid n-dodecyl ester, (meth) acrylic acid 2-methoxyethyl ester, (meth) acrylic acid 2-ethoxyethyl ester, (meth) acrylic acid 4-methoxy butyl ester, (meth ) 2- (2'-methoxyethoxy) acrylic acid ethyl ester, (meth) acrylic acid 2-hydroxyethyl ester, (meth) acrylic acid 2-hydroxy propyl ester, (meth) acrylic acid 3-hydroxypropyl ester, ( 4-hydroxybutyl meth) acrylic acid, ethylene glycol (meth) acrylate, propylene glycol (meth) acrylate, 1, 6-hexanediol di (meth) acrylate, 1, 2-ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, tetraethylene glycol di (meth) acrylate, tri- methylolpropane tri (meth) acrylate, trimethylolethane tri (meth) acrylate, pentaerythritol tri- and tetra (meth) acrylate, vinyl chloride, vinylidene chloride, vinyl acetate, vinyl propionate, vinyl butyrate, methyl vinyl ketone, vinyl toluene, vinyl naphthalene, methyl vinyl ether, ethyl vinyl ether, n-propyl propyl n-butyl vinyl ether, seJ-butyl vinyl ether, isobutyl vinyl ether, tert-butyl vinyl ether, 4-hydroxybutyl vinyl ether, n-octyl vinyl ether, ethylene, propylene, 1-butene, 2-butene, isobutene, cyclopentene, cyclohexene, cyclododecene, butadiene, Isoprene, chloroprene, styrene, α-methylstyrene, divinylbenzene, tert-butylstyrene and mixtures thereof.

Suitable secondary monomers are e.g.

(Meth) acrylic acid isobornyl ester, (meth) acrylic acid tridecyl ester, (meth) acrylic acid lauryl ester, (meth) acrylic acid stearyl ester, (meth) acrylic acid 10-cyclohexylundecyl ester, (meth) acrylic acid 2-cyanoethyl ester, (meth) acrylic acid 2 dimethylaminoethyl ester, (meth) acrylic acid glycidyl ester, (meth) acrylic acid 3- (trimethoxysilyl) propyl ester, (meth) acrylic acid 2- (trimethoxysilyl) ethyl ester, N- (2-hydroxyethyl) (meth) acrylamide, N, N-dimethyl (meth) acrylamide, N-tert-butyl (meth) acrylamide, N-octyl (meth) acrylamide, acrolein, (meth) acrylonitrile, fumaric acid di-isopropyl ester, fumaric acid di-n- butyl ester, fumaric acid di-butyl ester, fumaric acid diamine ester, fumaric acid di-2-ethylbutyl ester, fumaric acid di-n-octyl ester, fumaric acid di-2-ethylhexyl ester, fumaric acid didodecyl ester, bis- (2-hydroxyethyl) maleate fumarate, malate 2-ethylhexyl ester, maleic acid di (2-hydroxyethyl) ester, maleic acid nitrile, maleic acid di-nitrile, vinyl valerate, D ivinyl ether, 2-chloroethyl vinyl ether, α-propiolactone, δ-valerolactone, ε-caprolactone, N-vinylformamide, N-vinyl acetamide, N-vinyl-N-methylformamide, N-vinyl-N-methylacetamide, allylacetic acid, vinyl acetic acid and mixtures thereof ,

Functionalized monomers are, for example, those which

Carboxyl, hydroxyl, epoxy, allyl, carboxamide, A in, isocyanate, hydroxymethyl, methoxymethyl or silyloxy groups. These can be, for example, (meth) acrylic acid, (meth) acrylic acid formal, (meth) acrylic acid hydroxymethyl ester, (meth) acrylic acid benzophenone glycidyl ester, (meth) acrylic acid 2-sulfoethyl ester, (meth) acrylamide, N-methylol (meth) crylamide, fumarate acid, fumaric acid mono-iso-propyl ester, fumaric acid mono-n-hexyl ester, fumaric acid amide, fumaric acid diamide, fumaric acid nitrile, fumaric acid dinitrile, crotonic acid, crotonic acid glycidyl ester, itaconic acid, bicarbonate maleaic acid, malic acid acid citrate acid, citric acid iconic acid acid, Maleinsäuremonoethyl- ester, maleic acid monobutyl ester, maleic anhydride, maleic acid amide, maleic acid diamide, N-methylol maleic acid amide, vinyl succinimide, vinyl imidazole, 2-vinyl pyridine, 4-vinyl pyridine, N-vinyl pyrrolidone, N-vinyl piperidone, N-vinyl tetra-sulfanone, Diallyl phthalate, diallyl succinate, tetraallylethane, tetraallyloxysilane, allyl glycidyl ether, triallyl cyanurate, triallyl isocyanurate, diketene, monoethylenically unsaturated carboxylic acids having 3 to 8 carbon atoms and their water-soluble alkali metal, alkaline earth metal methacrylate, for example: methacrylate, acrylic acid, methacrylate, acrylic acid, methacrylate, acrylic acid, methacrylate, acrylic acid, methacrylate, acrylic acid, methacrylate, acrylic acid, methacrylate, acrylic acid, methacrylate, acrylic acid, methacrylate, acrylic acid, methacrylic acid, for example: acrylic acid, methacrylate, acrylic acid, methacrylate, acrylic acid, methacrylate, acrylic acid, methacrylate, acrylic acid, methacrylate, acrylic acid, methacrylate, methacrylate, acrylic acid, methacrylate, acrylic acid, methacrylate, acrylic acid; , Maleic acid, citraconic acid, methylene malonic acid, crotonic acid, fumaric acid, mesaconic acid or itaconic acid and mixtures thereof.

In order to obtain the specified T _g , these generally have a high proportion of n-butyl acrylate or 2-ethylhexyl acrylate, preferably at least 50% by weight.

The weight average molecular weight of the (co) polymers which can be used, if appropriate before further crosslinking (determined by gel permeation chromatography using polystyrene as the standard and tetrahydrofuran as the eluent), is for example between 200,000 and 1,500,000 g / mol, preferably between 250,000 and 1,200,000, particularly preferably between 300,000 and 900,000.

The gel content of the (co) polymers that can be used, i.e. the portion of an adhesive film which is soluble under THF when stored at room temperature for 24 hours is between 30 and 70, preferably between 30 and 60 and particularly preferably between 40 and 60% by weight.

Radiation-crosslinkable polyacrylates are particularly suitable according to the invention.

These are polyacrylates that can be cross-linked by active energy radiation. These adhesives generally contain poly (meth) acrylate, preferably polyacrylate, optionally in combination with aliphatic or aromatic epoxy resins, urethanes, polyesters or polyethers. Epoxy resins, aliphatic, aromatic or mixed aliphatic-aromatic urethanes are preferably used.

The crosslinking takes place by active energy radiation, but it can also be crosslinked via a second curing mechanism or further curing mechanisms (dual cure), for example by moisture, oxidation or the action of heat, preferably by heat, for example at the specified curing temperature. Crosslinking monomers can also be added, for example 1,3-butylene glycol di (meth) acrylate, tripropylene glycol di (meth) acrylate, trimethylolpropane triacrylate or pentaerythritol tetraacrylate.

A photoinitiator can be added for crosslinking by UV light.

However, the photoinitiator can also be bound to the poly (meth) acrylate. The photoinitiator can then e.g. cyclic imide structures, e.g. Maleimide or maleimide derivatives, benzo or acetophenone groups act. The latter are e.g. in EP-Bl 377 199, page 3, line 14 to page 13, line 45, and in EP-A 395 987, page 3, line 24 to page 5, line 42 and are hereby incorporated by reference.

The UV acrylates acResin ^® A 203 UV and acResin ^® A 258 UV from BASF AG, Ludwigshafen are particularly suitable.

Glissopal® or Oppanol® brands come as poly-iso-butenes (PIB) or modified poly-iso-butenes, for example the reaction products of PIB with maleic anhydride, hydroformylated PIB, hydroformylated and subsequently hydrogenated PIB and hydroformylated and then aminatingly hydrogenated PIB from BASF AG, Polybutene® brands from BP, the Infineum®-C series from Infineu Int. Ltd., Lubrizol® LZ brands from Lubrizol, Vistanex® brands from ExxonMobil Chemical Corp. , Tetrox® brands from Nippon Petrochemicals and Efrolen® brands from Efrimov. in question that have a molecular weight of approx. 200 to 1,000,000, preferably the Oppanole® BIO, B10N, B10SFN, B100, B100G, B12N, B12SF, B12SFN, B15, B15 BULK, B15N, B15SF, B15SFN, B150, B150G , B200, B200G, B246, B250, B30SF, B50, B50SF, B80, NTK and NTS, as well as the Glissopale® 1300, 2300, 550, 750, ES 3252, M 1600, OS, SA, V 1500, V 220, V 230, V33, V 500, V640, V700, V90 and 1000, Infineum® C9945, C9925, C9950, C9970, C9980, C9983, C9984, C9913, C9922, C9907, C9924 and C9995 as well as Vista-nex® L-80, L -100, L-120, L-140, LM-MS, LM-MH, LM-MS-LC, LM-MH-LC and LM-H-LC.

Of course, a mixture of different

Compounds with a glass transition temperature of -20 ° C or lower are used, for example 1 to 5, preferably 1 to 4, particularly preferably 1 to 3 and very particularly preferably 1 to 2 compounds. In particular, a connection is used. The radiation-curable compositions which can be used according to the invention in radiation-curable coating systems (F) are known per se and are not restricted, for example the radiation-curable clearcoats or topcoats known to those skilled in the art for such purposes. They generally contain at least one radical and / or cationically polymerisable group; they are preferably radically polymerisable.

Polymerizable groups can be those which have unsaturated bonds, preferably carbon-carbon double bonds.

Radically polymerizable groups are, for example, isolated ethylenically unsaturated groups, conjugated unsaturated groups, vinylaromatic groups, vinyl and vinylidene chloride groups, N-vinylamides, vinylpyrrolidones, vinyllactarne, vinyl esters, (meth) acrylic esters or acrylonitriles.

Cationically polymerizable groups are, for example, isobutylene units or vinyl ethers.

The preferred radiation-curable compositions preferably contain acrylate, methacrylate or vinyl ether functions as polymerizable groups.

Usually contains a radiation-curable composition that can be used according to the invention

(F1) at least one polymerizable compound with a plurality of copolymerizable, ethylenically unsaturated groups, (F2) optionally reactive diluent, (F3) optionally photoinitiator and (F4) optionally further paint-typical additives.

The compounds (F1) are radiation-curable, free-radically polymerizable compounds with several, i.e. at least two, copolymerizable, ethylenically unsaturated groups.

Compounds (F1) are preferably vinyl ether or (meth) acrylate compounds; particular preference is given to the acrylate compounds, ie the derivatives of acrylic acid. Preferred vinyl ether and (meth) acrylate compounds (F1) contain 2 to 20, preferably 2 to 10 and very particularly preferably 2 to 6 copolymerizable, ethylenically unsaturated double bonds.

Such compounds (F1) are particularly preferred with a content of ethylenically unsaturated double bonds of 0.1-0.7 ol / 100 g, very particularly preferably 0.2-0.6 mol / 100 g. Unless otherwise stated, the number-average molecular weight M _{n of} the compounds (F1) is preferably below 15000, particularly preferably 300-12000, very particularly preferably 400-5000 and in particular 500-3000 g / mol (determined by gel permeation chromatography with polystyrene as standard and tetrahydrofuran as eluent).

(Meth) acrylate compounds which may be mentioned are (meth) acrylic esters and in particular acrylic esters and vinyl ethers of polyfunctional alcohols, in particular those which, in addition to the hydroxyl groups, contain no further functional groups or at most ether groups. Examples of such alcohols are e.g. bifunctional alcohols such as ethylene glycol, propylene glycol and their more highly condensed representatives e.g. such as diethylene glycol, triethylene glycol, dipropylene glycol, tripropylene glycol etc., 1,2-, 1,3- or 1, 4-butanediol, 1, 5-pentanediol, 1, 6-hexanediol, 3-methyl-l, 5-pentanediol, neopentyl glycol , alkoxylated phenolic compounds, such as ethoxylated or propoxylated bisphenols, 1,2-, 1,3- or 1,4-cyclohexanedimethanol, trifunctional and higher functional alcohols, such as glycerol, trimethylolpropane, butanetriol, trimethylolethane, pentaerythritol, ditrimethyl lolpropane, dipentaerythritol, sorbitol, mannitol and the corresponding alkoxylated, in particular ethoxylated and / or propoxylated alcohols.

The alkoxylation products can be obtained in a known manner by reacting the above alcohols with alkylene oxides, in particular ethylene or propylene oxide. Preferably the degree of alkoxylation per hydroxyl group is 0 to 10, i.e. 1 mol of hydroxyl group can be alkoxylated with up to 10 mol of alkylene oxides.

Polyester (meth) acrylates may also be mentioned as (meth) acrylate compounds, which are the (meth) acrylic acid esters or vinyl ethers of polyesterols.

Examples of suitable polyesterols are those which can be prepared by esterifying polycarboxylic acids, preferably dicarboxylic acids, with polyols, preferably diols. The starting materials for such hydroxyl-containing polyesters are known to the person skilled in the art. Preferred dicarboxylic acids are succinic acid, glutaric acid, adipic acid, sebacic acid, o-phthalic acid, tetrahydrophthalic acid, terephthalic acid, their isomers and hydrogenation products, and esterifiable derivatives, such as anhydrides or dialkyl esters of the acids mentioned. Suitable polyols are the above-mentioned alcohols, preferably ethylene glycol, propylene glycol 1,2 and 1,3, butanediol 1,4, hexanediol 1,6, neopentyl glycol, cyclohexanedimethanol, 2,2-bis (4- hydroxycyclohexyl) propane and polyglycols of the ethylene glycol and propylene glycol types.

As radiation-curable compounds (Fl) come e.g. unsaturated polyester resins, which consist essentially of polyols, in particular diols, and polycarboxylic acids, in particular dicarboxylic acids, where one of the esterification components contains a copolymerizable, ethylenically unsaturated group. For example, it is maleic acid, fumaric acid or maleic anhydride.

Polyester (meth) acrylates can be used in several stages or in one stage, e.g. in EP-A 279 303, can be prepared from (meth) acrylic acid, polycarboxylic acid and polyol.

Furthermore, with connections (Fl) e.g. are urethane or epoxy (meth) acrylates or vinyl ethers.

Uretha (meth) acrylates are e.g. obtainable by reacting polyisocyanates with hydroxyalkyl (meth) acrylates or vinyl ethers and optionally chain extenders such as diols, polyols, diamines, polyamines or dithiols or polythiols. Urethane (meth) acrylates dispersible in water without the addition of emulsifiers additionally contain ionic and / or nonionic hydrophilic groups, which e.g. can be introduced into the urethane by structural components such as hydroxycarboxylic acids.

The polyurethanes which can be used according to the invention as binders (F1) essentially contain as structural components:

(Fl-a) at least one organic aliphatic, aromatic or cycloaliphatic di or polyisocyanate,

(Fl-b) at least one compound having at least one isocyanate-reactive group and at least one free-radically polymerizable unsaturated group and

(Fl-c) optionally at least one compound with at least two isocyanate-reactive groups. Suitable components (Fl-a) are, for example, aliphatic, aromatic and cycloaliphatic di- and polyisocyanates with an NCO functionality of at least 1.8, preferably 1.8 to 5 and particularly preferably 2 to 4, and their isocyanurates, biurets, allophanates and uretdione.

The diisocyanates are preferably isocyanates with 4 to 20 carbon atoms. Examples of customary diisocyanates are aliphatic diisocyanates such as tetramethylene diisocyanate, hexamethylene diisocyanate (1,6-diisocyanatohexane), octamethylene diisocyanate, decamethylene diisocyanate, dodecamethylene diisocyanate, tetradecamethylene diisocyanate, derivatives of lysine diisocyanate, trimethylene diisocyanate, tetramethylene diisocyanate, tetramethane diisocyanate , 3- or 1, 2-diisocyanatocyclohexane, 4,4'- or

2, 4 '-di (isocyanatocyclohexyl) methane, l-isocyanato-3, 3, 5-trimethyl-5- (isocyanatomethyl) cyclohexane (isophorone diisocyanate), 1,3- or 1,4-bis (isocyanatomethyl) cyclohexane or 2,4- or 2,6-diisocyanato-1-methylcyclohexane and aromatic diisocyanates such as 2,4- or 2,6-tolylene diisocyanate and their isomer mixtures, m- or p-xylylene diisocyanate, 2,4'- or 4, 4'-diisocyanatodiphenylmethane and its isomer mixtures, 1,3- or 1, -phenylene diisocyanate, l-chloro-2, 4-phenylene diisocyanate, 1, 5-naphthylene diisocyanate, diphenylene, 4 'diisocyanate, 4, 4'-diisocyanato -3, 3 '-dimethyldiphenyl, 3-methyldiphenylmethane-4,4'-diisocyanate, tetramethylxylylene diisocyanate, 1,4-diisocyanatobenzene or diphenyl ether-4,4'-diisocyanate.

Mixtures of the diisocyanates mentioned can also be present.

Hexamethylene diisocyanate, 1,3-bis (isocyanatomethyl) cyclohexane, isophorone diisocyanate and di (isocyanatocyclohexyl) methane are preferred.

As polyisocyanates there are polyisocyanates containing isocyanurate groups, uretdione diisocyanates, polyisocyanates containing biuret groups, polyisocyanates containing urethane or allophanate groups, polyisocyanates containing oxadiazinetrione groups, uretoneimine-modified polyisocyanates of straight-chain or branched C4-co-alkylene diisocyanate to 20-cycloaliphatic diisocyanates -Atoms or aromatic diisocyanates with a total of 8 to 20 carbon atoms or mixtures thereof.

The di- and polyisocyanates that can be used preferably have one

Isocyanate group content (calculated as NCO, molecular weight = 42) from 10 to 60% by weight, based on the di- and polyiso cyanate (mixture), preferably 15 to 60% by weight and particularly preferably 20 to 55% by weight.

Aliphatic or cycloaliphatic di- and poly-isocyanates, e.g. the aliphatic or cycloaliphatic diisocyanates mentioned above, or mixtures thereof.

Are also preferred

1) Isocyanurate group-containing polyisocyanates of aromatic, aliphatic and / or cycloaliphatic diisocyanates. The corresponding aliphatic and / or cycloaliphatic isocyanato-isocyanates and particularly those based on hexamethylene diisocyanate and isophorone diisocyanate are particularly preferred. The isocyanurates present are in particular tris-isocyanatoalkyl or tris-isocyanatocycloalkyl isocyanurates, which are cyclic trimers of the diisocyanates, or mixtures with their higher homologues having more than one isocyanurate ring. The isocyanato-isocyanurates generally have an NCO content of 10 to 30% by weight, in particular 15 to 25% by weight, and an average NCO functionality of 3 to 4.5.

2) Uretdione diisocyanates with aromatic, aliphatic and / or cycloaliphatic isocyanate groups, preferably aliphatic and / or cycloaliphatic bound and in particular those derived from hexamethylene diisocyanate or isophorone diisocyanate. Uretdione diisocyanates are cyclic dimerization products of diisocyanates. The uretdione diisocyanates can be used in the preparations as the sole component or in a mixture with other polyisocyanates, in particular those mentioned under 1).

3) Polyisocyanates containing biuret groups with aromatic, cycloaliphatic or aliphatic bound, preferably cycloaliphatic or aliphatic, bound isocyanate groups, in particular tris (δ-isocyanatohexyl) biuret or its mixtures with its higher homologues. These polyisocyanates containing biuret groups generally have an NCO content of 18 to 22% by weight and an average NCO functionality of 3 to 4.5.

4) Polyisocyanates containing urethane and / or allophanate groups with aromatic, aliphatic or cycloaliphatic bound, preferably aliphatic or cycloaliphatic, bound which isocyanate groups, such as those obtained by reacting excess amounts of hexamethylene diisocyanate or isophorone diisocyanate with polyhydric alcohols, such as trimethylolpropane, neopentyl glycol, pentaerythritol, 1,4-butanediol, 1,6-hexanediol, 1,3-propanediol, ethylene glycol, diethylene glycol, glycerol , 1,2-dihydroxypropane or mixtures thereof can be obtained. These polyisocyanates containing urethane and / or allophanate groups generally have an NCO content of 12 to 20% by weight and an average NCO functionality of 2.5 to 3.

5) Polyisocyanates containing oxadiazinetrione groups, preferably derived from hexamethylene diisocyanate or isophorone diisocyanate. Such isocyanates containing oxadiazinetrione groups can be prepared from diisocyanate and carbon dioxide.

6) Uretonimine-modified polyisocyanates.

The polyisocyanates 1) to 6) can be used in a mixture, if appropriate also in a mixture with diisocyanates.

Compounds (Fl-b) which have at least one group which is reactive toward isocyanate and at least one group which can be polymerized by free radicals are suitable.

Groups reactive toward isocyanate can be, for example, -OH, -SH, -NH and -NHR ¹ , where R ^{1 is} hydrogen or an alkyl group containing 1 to 4 carbon atoms, such as methyl, ethyl, n-propyl, iso-propyl, n-butyl , isobutyl, SeJc-butyl or tert-butyl.

Components (Fl-b) can e.g. Monoesters of α, β-unsaturated carboxylic acids, such as acrylic acid, methacrylic acid, crotonic acid, itaconic acid, fumaric acid, maleic acid, acrylamidoglycolic acid, methacrylamidoglycolic acid or vinyl ether with di- or polyols, which preferably have 2 to 20 C atoms and at least two hydroxyl groups, such as ethylene glycol , Diethylene glycol, triethylene glycol, 1, 2-propylene glycol, 1,3-propylene glycol, 1, 1-dimethyl-l, 2-ethanediol, dipropylene glycol, triethylene glycol, tetraethylene glycol, pentaethylene glycol, tripropylene glycol,

1, 4-butanediol, 1, 5-pentanediol, neopentyl glycol, 1, 6-hexanediol, 2-methyl-l, 5-pentanediol, 2-ethyl-l, 4-butanediol, 1, 4-dimethylol-cyclohexane, 2, 2-bis (4-hydroxycyclohexyl) propane, glycerol, trimethylolethane, trimethylolpropane, trimethylolbutane, pentaerythritol, ditrimethylolpropane, erythritol, sorbitol, poly-THF with a molecular weight between 162 and 2000, poly-1,3-propanediol with a Molecular weight between 134 and 400 or with polyethylene glycol a molecular weight between 238 and 458. Furthermore, esters or aides of (meth) acrylic acid with amino alcohols, for. B. 2-aminoethanol, 2- (methylamino) ethanol, 3-amino-l-propanol, l-amino-2-propanol or 2- (2-aminoethoxy) ethanol, 2-mercaptoethanol or polyaminoalkanes such as ethylenediamine or diethylene - triamine or vinyl acetic acid can be used.

Unsaturated polyether or polyesterols or polyacrylate polyols with an average OH functionality of 2 to 10 are also suitable.

Examples of amides of ethylenically unsaturated carboxylic acids with amino alcohols are hydroxyalkyl (meth) acrylamides such as N-hydroxymethyl acrylamide, N-hydroxymethyl methacrylamide, N-hydroxyethyl methacrylamide, N-hydroxyethyl methacrylamide, 5-hydroxy-3-oxapentyl (meth) acrylamide, N Hydroxyalkylcrotonamides such as N-hydroxymethylcrotonamide or N-hydroxyalkylmaleinimides such as N-hydroxyethylmaleinimide.

2-Hydroxyethyl (meth) acrylate, 2- or 3-hydroxypropyl (meth) acrylate, 1,4-butanediol mono (meth) acrylate, neopentyl glycol mono (meth) acrylate, 1,5-pentanediol mono (meth) acrylate are preferably used, 1, 6-hexanediol mono (meth) acrylate, glycerol mono- and di (meth) acrylate, trimethylolpropane mono- and di (meth) acrylate, pentaerythritol mono-, di- and tri (meth) acrylate as well as 4-hydroxybutyl vinyl ether, 2- Aminoethyl (meth) acrylate, 2-aminopropyl (meth) acrylate, 3-aminopropyl (meth) acrylate, 4-aminobutyl (meth) acrylate, 6-aminohexyl (meth) acrylate, 2-thioethyl (meth) acrylate, 2-aminoethyl (meth) acrylamide, 2-aminopropyl (meth) acrylamide, 3-aminopropyl (meth) acrylamide, 2-hydroxyethyl (meth) acrylamide, 2-hydroxypropyl (meth) acrylamide or 3-hydrσxypropyl ( meth) acrylamide. 2-Hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, 2- or 3-hydroxypropyl acrylate, 1,4-butanediol monoacrylate and 3- (acryloyloxy) -2-hydroxypropyl methacrylate are particularly preferred.

Component (Fl-c) are compounds which contain at least two groups which are reactive toward isocyanate, for example -OH, -SH, -NH or -NHR ² , in which R ² is independently hydrogen, methyl, ethyl, isopropyl, may mean n-propyl, n-butyl, isobutyl, seJc-butyl or tert-butyl.

These are preferably diols or polyols, such as hydrocarbon diols having 2 to 20 carbon atoms, for example ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,1-dimethylethane-1,2-diol, 1,6-hexanediol, 1, 10-decanediol, bis (4-hydroxycyclohexane) isopropylidene, tetramethylcyclobutanediol, 1,2-, 1,3- or 1,4-cyclo- hexanediol, cyclooctanediol, norbornanediol, pinanediol, decalinediol, etc., their esters with short-chain dicarboxylic acids, such as adipic acid, cyclohexanedicarboxylic acid, their carbonates, prepared by reaction of the diols with phosgene or by transesterification with dialkyl or diaryl carbonates, or aliphatic diamines, such as methylene -, and isopropylidene-bis- (cyclohexylamine), piperazine, 1,2-, 1,3- or 1,4-diaminocyclohexane, 1,2-, 1,3- or 1,4-cyclohexane-bis- ( methylamine), etc., dithiols or polyfunctional alcohols, secondary or primary amino alcohols, such as ethanolamine, diethanolamine, monopropanolamine, dipropanolamine etc. or thioalcohols, such as thioethylene glycol.

Diethylene glycol, triethylene glycol, dipropylene glycol, tripropylene glycol, neopentyl glycol, pentaerythritol, 1,2- and 1,4-butanediol, 1,5-pentanediol are also conceivable.

2-methyl-l, 5-pentanediol, 2-ethyl-l, 4-butanediol, 1,2-, 1,3- and 1,4-dimethylolcyclohexane, 2,2-bis (4-hydroxycyclohexyl) propane, glycerol, Trimethylolethane, trimethylolpropane, trimethylolbutane, dipentaerythritol, ditrimethylolpropane, erythritol and sorbitol, 2-aminoethanol, 3-amino-l-propanol, l-amino-2-propanol or 2- (2-aminoethoxy) ethanol, bisphenol A, or butanetriol.

Unsaturated polyether or polyesterols or polyacrylate polyols with an average OH functionality of 2 to 10 are also suitable, as are polyamines, e.g. Polyethyleneimine or free amine group containing polymers of e.g. Poly-N-vinylformamide.

The cycloaliphatic diols, such as e.g. Bis (4-hydroxycyclohexane) isopropylidene, tetramethylcyclobutane diol, 1,2-, 1,3- or 1,4-cyclohexane diol, cyclooctane diol or norbornane diol.

The polyurethanes which can be used according to the invention are obtained by reacting components (Fl-a), (Fl-b) and (Fl-c) with one another.

The molar composition (Fl-a): (Fl-b): (Fl-c) per 3 mol reactive isocyanate groups in (Fl-a) is usually as follows: (Fl-b) 1.5 - 3, 0, preferably 2.0-2.9, particularly preferably 2.0-2.5 and in particular 2.0-2.3 mol of groups reactive toward isocyanate and

(Fl-c) 0-1.5, preferably 0.1-1.0, particularly preferably 0.5-1.0 and in particular 0.7-1.0 mol of isocyanate-reactive groups. When the polyurethanes are used in aqueous systems, essentially all of the isocyanate groups present have preferably reacted.

The formation of the adduct from the compound containing isocyanate groups and the compound which contains groups reactive toward isocyanate groups is generally carried out by mixing the components in any order, if appropriate at elevated temperature.

The compound which contains groups reactive toward isocyanate groups is preferably added to the compound containing isocyanate groups, preferably in several steps.

The compound containing isocyanate groups is particularly preferably introduced and the compounds which contain groups reactive toward isocyanate are added. In particular, the isocyanate group-containing compound (Fl-a) is initially introduced and then (Fl-b) is added. If desired, further desired components can subsequently be added.

As a rule, the reaction is carried out at temperatures between 5 and 100 ° C., preferably between 20 to 90 ° C. and particularly preferably between 40 and 80 ° C. and in particular between 60 and 80 ° C.

It is preferred to work under anhydrous conditions.

Anhydrous means that the water content in the reaction system is not more than 5% by weight, preferably not more than 3% by weight and particularly preferably not more than 1% by weight.

Preferably the reaction is carried out in the presence of at least one suitable inert gas, e.g. Nitrogen, argon, helium, carbon dioxide or the like.

The reaction can also be carried out in the presence of an inert solvent, e.g. Acetone, isobutyl methyl ketone, toluene, xylene, butyl acetate or ethoxyethyl acetate. However, the reaction is preferably carried out in the absence of a solvent.

The urethane (meth) acrylates preferably have a number average molecular weight M _n of 500 to 20,000, in particular 750 to 10,000, particularly preferably 750 to 3000 g / mol (determined by gel permeation chromatography with tetrahydrofuran and polystyrene as standard). The urethane (meth) acrylates preferably have a content of 1 to 5, particularly preferably 2 to 4, moles of (meth) acrylic groups per 1000 g of urethane (meth) acrylate.

The urethane vinyl ethers preferably have a content of 1 to 5, particularly preferably 2 to 4, mol of vinyl ether groups per 1000 g of urethane vinyl ether.

Epoxy (meth) acrylates can be obtained by reacting epoxides with (meth) acrylic acid. Examples of suitable epoxides are epoxidized olefins, aromatic glycidyl ethers or aliphatic glycidyl ethers, preferably those of aromatic or aliphatic glycidyl ethers.

Epoxidized olefins can be, for example, ethylene oxide,

Propylene oxide, isobutylene oxide, 1-butene oxide, 2-butene oxide, vinyl oxirane, styrene oxide or epichlorohydrin, preference is given to ethylene oxide, propylene oxide, isobutylene oxide, vinyl oxirane, styrene oxide or epichlorohydrin, particularly preferably ethylene oxide, propylene oxide or epichlorohydrin and very particularly preferably ethylene oxide and epichlorohydrin.

Aromatic glycidyl ethers are e.g. Bisphenol A diglycidyl ether, bisphenol F diglycidyl ether, bisphenol B diglycidyl ether, bisphenol S diglycidyl ether, hydroquinone diglycidyl ether, alkylation products of phenol / dicyclopentadiene, e.g. 2,5-bis [(2,3-epoxypropoxy) phenyl] octahydro-4,7-methano-5H-indene) (CAS No. [13446-85-0]), Tris [4- (2, 3-epoxypropoxy) phenyl] methane isomers (CAS No. [66072-39-7]), phenol based epoxy novolaks (CAS No. [9003-35-4]) and cresol based epoxy novolaks (CAS No. [ 37382-79-9]).

Aliphatic glycidyl ethers are, for example, 1,4-butanediol diglycidyl ether, 1,6-hexanediol diglycidyl ether, trimethylolpropane triglycidyl ether, pentaerythritol tetraglycidyl ether, 1, 1,2,2-tetrahis [4- (2,3-epoxypropoxy) phenyl] ethane ( No. [27043-37-4]), diglycidyl ether of polypropylene glycol (α, ω-bis (2, 3-epoxypropoxy) poly (oxypropylene) (CAS No. [16096-30-3]) and of hydrogenated Bisphenol A (2,2-bis [4- (2,3-epoxypropoxy) cyclohexyl] propane, CAS No. [13410-58-7]).

The epoxy (meth) acrylates and vinyl ethers preferably have a number-average molecular weight M _n of 340 to 20,000, particularly preferably from 500 to 10,000 g / mol and very particularly preferably from 750 to 3000 g / mol; the content of (meth) acrylic or vinyl ether groups is preferably 1 to 5, particularly preferably 2 to 4 per 1000 g of epoxy (meth) acrylate or vinyl ether epoxide (determined by Gel permeation chromatography with polystyrene as standard and tetrahydrofuran as eluent).

Further suitable radiation-curable compounds (F1) are carbonate (meth) acrylates which on average preferably contain 1 to 5, in particular 2 to 4, particularly preferably 2 to 3 (meth) acrylic groups and very particularly preferably 2 (meth) acrylic groups.

The number average molecular weight M _{n of} the carbonate (meth) acrylates is preferably less than 3000 g / mol, particularly preferably less than 1500 g / mol, particularly preferably less than 800 g / mol (determined by gel permeation chromatography with polystyrene as standard, solvent tetrahydrofuran).

The carbonate (meth) acrylates can be obtained in a simple manner by transesterification of carbonic acid esters with polyhydric, preferably dihydric alcohols (diols, for example hexanediol) and subsequent esterification of the free OH groups with (meth) acrylic acid or transesterification with (meth) acrylic acid esters as it is e.g. is described in EP-A 92 269. They are also available by converting phosgene, urea derivatives with polyvalent, e.g. dihydric alcohols.

Vinyl ether carbonates can also be obtained in an analogous manner by reacting a hydroxyalkyl vinyl ether with carbonic acid esters and, if appropriate, dihydric alcohols.

Also conceivable are (meth) acrylates or vinyl ethers of polycarbonate polyols, such as the reaction product of one of the di- or polyols mentioned and a carbonic acid ester as well as a (meth) acrylate or vinyl ether containing hydroxyl groups.

Suitable carbonic acid esters are e.g. Ethylene, 1,2- or 1,3-propylene carbonate, dimethyl, diethyl or di-butyl carbonate.

Suitable hydroxy group-containing (meth) acrylates are, for example, 2-hydroxyethyl (meth) acrylate, 2- or 3-hydroxypropyl (meth) acrylate, 1,4-butanediol mono (meth) acrylate, neopentyl glycol mono (meth) acrylate, glycerol mono- and di (meth) acrylate, trimethylolpropane mono- and di (meth) acrylate and pentaerythritol mono-, di- and tri (meth) acrylate.

Suitable hydroxy group-containing vinyl ethers are, for example, 2-hydroxyethyl vinyl ether and 4-hydroxybutyl vinyl ether. Particularly preferred carbonate (meth) acrylates are those of the formula:

wherein R is H or CH ₃ , X is a C ₂ -C ₈ alkylene group and n is an integer from 1 to 5, preferably 1 to 3.

R is preferably H and X is preferably C ₂ - to Cio-alkylene, for example 1,2-ethylene, 1, 2-propylene,

1,3-propylene, 1,4-butylene or 1,6-hexylene, particularly preferably for C ₄ - to Cs-alkylene. X very particularly preferably represents C ₆ -alkylene.

They are preferably aliphatic carbonate (meth) acrylates.

Furthermore, (meth) acrylates or vinyl ethers of polyether polyols can also be used as radiation-curable compounds (F1). These can be one or preferably multivalued, in statistical terms

Polether alcohols containing 2 to 70, preferably 2 to 60, polyalkylene oxide units per molecule, as are obtainable in a manner known per se by alkoxylation of suitable starter molecules. Any monohydric or polyhydric alcohols can be used as starter molecules to produce these polether alcohols.

Alkylene oxides suitable for the alkoxylation are ethylene oxide, propylene oxide, butylene oxide, isobutylene oxide and vinyl oxirane, which can be used in any order or as a mixture in the alkoxylation reaction.

Suitable starter molecules are, for example, trimethylolpropane, trimethylolethane, neopentylglycol, pentaerythritol, glycerin, ditrimethylolpropane, dipentaerythritol, sorbitol, mannitol, diglycerol, 1,2-propanediol, ethylene glycol, 2,2-dimethyl-1,2-ethanediol, neopentyl glycol , 1, 3-propanediol, 1, 2-butanediol or 1, 4-butanediol. Polyether alcohols containing vinyl ether groups are obtained, for example, by reacting hydroxyalkyl vinyl ethers with alkylene oxides.

Polyether alcohols containing (meth) acrylic acid groups can be obtained, for example, by transesterifying (meth) acrylic esters with the polyether alcohols, by esterifying the polyether alcohols with (meth) acrylic acid or by using (meth) acrylates containing hydroxyl groups as described above under (Fl-b) become.

Preferred polether alcohols are polyethylene glycols with a molecular weight between 106 and 2000, preferably between 106 and 898, particularly preferably between 238 and 678.

Poly-THF with a molecular weight between 162 and 2000 and poly-1,3-propanediol with a molecular weight between 134 and 1178 can also be used as polyether alcohols.

Particularly preferred compounds (F1) are urethane or carbonate (meth) acrylates or vinyl ethers, in particular urethane (meth) acrylates.

Compounds (F1) are often used in a mixture with compounds (F2), which serve as reactive diluents.

Suitable reactive diluents (compounds (F2)) are radiation-curable, free-radically or cationically polymerizable compounds having only one ethylenically unsaturated, copolymerizable group.

Examples include C ₁ -C ₂ -alkyl (meth) acrylates, vinyl aromatics with up to 20 C atoms, vinyl esters of up to 20 C atoms containing carboxylic acids, ethylenically unsaturated nitriles, vinyl ethers with 1 to 10 C atoms Alcohols, α, ß-unsaturated carboxylic acids and their anhydrides and aliphatic hydrocarbons with 2 to 8 carbon atoms and 1 or 2 double bonds.

The term (meth) acrylic acid is used in the context of this document for acrylic acid and methacrylic acid.

Preferred (meth) acrylic acid alkyl esters are those with a C 1 -C 8 -alkyl radical, such as methyl methacrylate, methyl acrylate, n-butyl acrylate, ethyl acrylate and 2-ethylhexyl acrylate. Mixtures of the (meth) acrylic acid alkyl esters are also particularly suitable.

Vinyl esters of carboxylic acids with 1 to 20 C atoms are e.g. Vinyl laurate, vinyl stearate, vinyl propionate and vinyl acetate.

α, β-Unsaturated carboxylic acids and their anhydrides can be, for example, acrylic acid, methacrylic acid, fumaric acid, crotonic acid, itaconic acid, maleic acid or maleic anhydride, preferably acrylic acid.

As vinyl aromatic compounds there are e.g. Vinyl toluene, α-butylstyrene, 4-n-butylstyrene, 4-n-decylstyrene and preferably styrene are considered.

Examples of nitriles are acrylonitrile and methacrylonitrile.

Suitable vinyl ethers are e.g. Vinyl methyl ether, vinyl isobutyl ether, vinyl hexyl ether and vinyl octyl ether.

Butadiene, isoprene, and also ethylene, propylene and isobutylene may be mentioned as non-aromatic hydrocarbons having 2 to 8 carbon atoms and one or two olefinic double bonds.

N-vinylformamide, N-vinylpyrrolidone and N-vinylcaprolactam can also be used.

Photoinitiators known to those skilled in the art can be used as photoinitiators (F3), e.g. those in "Advances in Polymer Science", Volume 14, Springer Berlin 1974 or in K.K. Dietiker, Chemistry and Technology of UV and EB Formulation for Coatings, Inks and Paints, Volume 3; Photoinitiators for Free Radical and Cationic Polymerization, P.K.T. Oldring (Eds), SITA Technology Ltd, London.

For example, mono- or bisacylphosphine oxides such as Irgacure® 819 (bis (2,4, 6-trimethylbenzoyl) phenylphosphine oxide), as described, for example, in EP-A 7 508, EP-A 57 474, DE-A 196 18 720 , EP-A 495 751 are described or EP-A 615 980, for example, 2,4,6-tri- methylbenzoyldiphenylphosphinoxid (Lucirin ^® TPO),

Ethyl-2, 4, 6-trimethylbenzoylphenylphosphinate, benzophenones, hydroxyacetophenones, phenylglyoxylic acid and their derivatives or mixtures of these photoinitiators. Examples are benzophenone, acetophenone, Acetonaphthochinon, methyl ethyl ketone, valerophenone, hexanophenone, α-phenyl-butyrophenone, p-morpholino propiophenone, dibenzosuberone, 4-morpholinobenzophenone, 4-morpholine linodeoxybenzoin, p-diacetylbenzene, 4-aminobenzophenone, 4'-Metho - xyacetophenone, ß-methylanthraquinone, terfc-butylanthraquinone, anthraquinone carbonate, benzaldehyde, α-tetralone, 9-acetylphenanthrene, 2-acetylphenanthrene, 10-thioxanthenone, 3-acetylphenanthrene, 1-fluorenylindole Indanon, 1, 3, 4-triacetylbenzene, thioxanthene-9-one, xanthene-9-one, 2,4-dimethylthioxanthone, 2,4-diethylthioxanthone, 2, 4-di-iso-propylthioxanthone, 2,4- Dichlorothioxanthone, benzoin, benzoin isobutyl ether, chloroxanthenone, benzoin tetrahydropyranyl ether, benzoin methyl ether, benzoin ethyl ether, benzoin butyl ether, benzoin isopropyl ether, 7-H-benzoin methyl ether, benz [de] anthracen-7-one, 1-naphthaldehyde,

4,4'-bis (imethylamino) benzophenone, 4-phenylbenzophenone, 4-chlorobenzophenone, Michler's ketone, 1-acetonaphthone, 2-acetonaphthone, 1-benzoylcyclohexan-l-ol, 2-hydroxy-2, 2-dimethylacetophenone, 2,2-dimethoxy-2-pb.enylacetoph.enone, 2,2-diethoxy-2-phenylaceto-phenone, 1,1-dichloroacetophenone, 1-hydroxyacetophenone, acetophenondimethyl ketal, o-methoxybenzophenone, triphenylphosphine, tri-o- Tolylphosphine, benz [a] anthracen-7, 12-dione, 2,2-diethoxyacetophenone, benzil ketals such as benzil dimethyl ketal, 2-methyl-1- [4- (methylthio) phenyl] -2-morpholinopropan-l-one, Anthraquinones such as 2-methylanthraquinone, 2-ethylanthraquinone,

2- ert-butylanthraquinone, 1-chloroanthraquinone, 2-amylanthraquinone and 2,3-butanedione.

Also suitable are non-yellowing or little yellowing photoinitiators of the phenylglyoxalic acid ester type, as described in DE-A 198 26 712, DE-A 199 13 353 or WO 98/33761.

Among the photoinitiators mentioned, phosphine oxides, α-hydroxyketones and benzophenones are preferred.

In particular, mixtures of different photoinitiators can also be used.

The photoinitiators can be used alone or in combination with a photopolymerization promoter, e.g. of the benzoic acid, amine or similar type can be used.

Other typical coatings additives (F4) include, for example, antioxidants, oxidation inhibitors, stabilizers, activators (accelerators), fillers, pigments, dyes, degassing agents, brighteners, antistatic agents, flame retardants, thickeners, thixotropic agents, flow control agents, binders, antifoams, fragrances, surface-active agents , Viscosity modifiers, plasticizers, plasticizers, tackifying resins (tackifiers), chelating agents or compatibilizers (compatibilizers). Tin octoate, zinc octoate, dibutyltin laurate or diazabicyclo [2.2.2] octane, for example, can be used as accelerators for the thermal post-curing.

Furthermore, one or more photochemically and / or thermally activatable initiators can be added, e.g. Potassium peroxodisulfate, dibenzoyl peroxide, cyclohexanone peroxide, di-tert-butyl peroxide, azobis-iso-butyronitrile, cyclohexylsulfonylacetyl peroxide, di-iso-propyl percarbonate, tert-butyl peroctoate or benzopinacol, and initiators such as these, which are thermally active and die-activators Have half-life at 80 ° C of more than 100 hours, such as di-t-butyl peroxide, cumene hydroperoxide, dicumyl peroxide, t-butyl perbenzoate, silylated pinacoles, the z. B. are commercially available under the trade name ADDID 600 from Wacker or amine N-oxides containing hydroxyl groups, such as 2,2,6,6-tetramethylpiperidine-N-oxyl, 4-hydroxy-2, 2.6, 6-tetramethylpiperidine-N-oxyl etc.

Further examples of suitable initiators are described in "Polymer Handbook", 2nd edition, Wiley & Sons, New York.

In addition to radical (co) polymerized (co) polymers, conventional organic and inorganic thickeners such as hydroxymethyl cellulose or bentonite are suitable as thickeners.

As chelating agents e.g. Ethylenediamine acetic acid and its salts and β-diketones are used.

Suitable fillers include silicates, e.g. B. by hydrolysis of silicon tetrachloride available silicates such as Aerosil ^® from Degussa, silica, talc, aluminum silicates, magnesium silicates, calcium carbonates etc.

Suitable stabilizers include typical UV absorbers such as oxanilides, triazines and benzotriazole (the latter available as Tinuvin ^® brands from Ciba-Spezialicheche ie) and benzophenones. These can be used alone or together with suitable radical scavengers, for example sterically hindered amines such as 2, 2, 6, 6-tetramethylpiperidine, 2, 6-di-tert. -butylpiperidine or its derivatives, e.g. B. bis- (2, 2, 6, 6-tetra-methyl-4-piperidyl) sebacinate can be used. Stabilizers are usually used in amounts of 0.1 to 5.0% by weight, based on the solid components contained in the preparation.

Other suitable stabilizers are, for example, N-oxyls, such as 4-hydroxy-2, 2,6, 6-tetramethyl-piperidine-N-oxyl, 4-oxo-2, 2,6, 6-tetramethyl-piperidine-N-oxyl , 4-acetoxy-2, 2,6, 6-te tramethyl-piperidine-N-oxyl, 2,2,6, 6-tetramethyl-piperidine-N-oxyl, 4, 4 ', 4''tris (2,2,6, 6-tetramethyl-piperidine-N-oxyl ) phosphite or 3-oxo-2,2,5,5-tetramethyl-pyrrolidine-N-oxyl, phenols and naphthols, such as, for example, p-aminophenol, p-nitrosophenol, 2-tert.-butylphenol, 4 -terfc.-butylph.enol, 2,4-di-fcerfc.-butylphenol,

2-methyl-4-fcerfc.-butylphenol, 4-methyl-2, 6-terfc.-butylphenol (2, 6-terfc. -Butyl-p-cresol) or 4-terfc. Butyl-2, 6-dimethylphenol, quinones, e.g. Hydroquinone or hydroquinone monomethyl ether, aromatic amines such as e.g. N, N-diphenylamine, N-nitrosodiphenyl laminate, phenylenediamines, such as e.g. N, N'-dialkyl-para-phenylenediamine, where the alkyl radicals can be the same or different and each independently consist of 1 to 4 carbon atoms and can be straight-chain or branched, hydroxylamines, such as e.g. N, N-diethylhydroxylamine, urea derivatives such as e.g. Urea or thiourea, phosphorus-containing compounds such as e.g. Triphenylphosphine, triphenylphosphite or triethylphosphite or sulfur-containing compounds such as e.g. Diphenyl sulfide or phenothiazine.

Typical compositions for radiation-curable compositions are, for example

(Fl) 0-100% by weight, preferably 50-90, particularly preferably 60-90 and in particular 60-80% by weight, (F2) 0-60% by weight, preferably 5-50, particularly preferably 6-40 and especially 10- 30% by weight, (F3) 0-20% by weight, preferably 0.5 - 15, particularly preferably 1-10 and in particular 2-5% by weight and (F4) 0 - 50% by weight, preferably 2-40, particularly preferably 3 - 30 and in particular 5 - 20% by weight,

with the proviso that (Fl), (F2), (F3) and (F4) together add up to 100% by weight.

In the case of particularly preferred radiation-curable compositions, the compound (Fl) consists of 10 to 100% by weight, based on the total amount of the compound (Fl), of urethane (meth) acrylate (s), epoxy acrylates, polyether acrylates or polyester acrylates.

Particularly suitable radiation-curable compositions which can be used as layers (F) are those in EP-AI 942 022, particularly from S.

4, line 18 to page 18, line 31, which are described in DE-Al 199 44 156,

5. 1, line 26 to page 6, line 63 and in DE-Al 199 56 231, page 2, line 33 to page 4, line 65, as well as in the German patent application with the file number 101 40 769.6 and the filing date 20.08.2001. The substrates are coated by customary processes known to the person skilled in the art, at least one coating composition being applied to the substrate to be coated in the desired thickness and the volatile constituents of the coating composition which may be present being removed, if appropriate with heating. If desired, this process can be repeated one or more times. The application to the substrate can in a known manner, for. B. by spraying, filling, knife coating, brushing, rolling, rolling, casting, laminating, back molding or coextruding. The coating thickness is generally in a range from about 3 to 1000 g / m ² and preferably 10 to 200 g / m ² .

Furthermore, a method for coating substrates is disclosed in which the coating composition is applied to the substrate and optionally dried, cured with electron beams or UV exposure under an oxygen-containing atmosphere or preferably under an inert gas, if appropriate at temperatures up to the drying temperature and then at Temperatures up to 160 ° C, preferably between 60 and 160 ° C, thermally treated.

The process for coating substrates can also be carried out in such a way that after the coating composition has been applied, it is first thermally treated at temperatures up to 160 ° C., preferably between 60 and 160 ° C., and then with electron beams or UV exposure under oxygen or preferably under inert gas is hardened.

If desired, the films formed on the substrate can only be cured thermally. In general, however, the coatings are cured both by irradiation with high-energy radiation and thermally.

The curing can also take place in addition to or instead of the thermal curing by means of NIR radiation, electromagnetic radiation in the wavelength range from 760 nm to 2.5 μm, preferably from 900 to 1500 n, being referred to here as NIR radiation.

If necessary, if several layers of the coating composition are applied one above the other, thermal, NIR and / or radiation curing can take place after each coating process.

Suitable radiation sources for radiation curing are, for example, low-pressure mercury lamps, medium-pressure lamps with high-pressure lamps and fluorescent tubes, pulse lamps, metal halide lamps, and electronic flash devices, which means that Radiation curing is possible without a photoinitiator, or excimer emitters. Radiation curing takes place by the action of high-energy radiation, that is to say UV radiation or daylight, preferably emitting light in the wavelength range from λ = 200 to 700 nm, particularly preferably from λ = 200 to 500 nm and very particularly preferably λ = 250 to 400 nm, or by Irradiation with high-energy electrons (electron radiation; 150 to 300 keV). High-pressure mercury vapor lamps, lasers, pulsed lamps (flashing light), halogen lamps or excimer lamps are used as radiation sources. The radiation dose usually sufficient for crosslinking in UV curing is in the range from 80 to 3000 mJ / cm.

Of course, several radiation sources can also be used for curing, e.g. two to four.

These can also radiate in different wavelength ranges.

The radiation can optionally also be in the absence of oxygen, for. B. be carried out under an inert gas atmosphere. Suitable inert gases are preferably nitrogen, noble gases, carbon dioxide or combustion gases. Irradiation can also be carried out by covering the coating material with transparent media. Transparent media are e.g. B. plastic films, glass or liquids, eg. B. water. Irradiation in the manner described in DE-Al 199 57 900 is particularly preferred.

Another object of the invention is a method for coating substrates, wherein

i) coating a substrate with a coating composition, as described above,

ii) volatile constituents of the coating composition are removed for film formation under conditions in which the photoinitiator (C) essentially does not yet form any free radicals,

iii) optionally irradiating the film formed in step ii) with high-energy radiation, the film being prehardened, and then optionally machining the object coated with the prehardened film or bringing the surface of the prehardened film into contact with another substrate, iv) final curing of the film thermally or with NIR radiation. Steps iv) and iii) can also be carried out in the reverse order, ie the film can first be cured 5 thermally or by NIR radiation and then with high-energy radiation.

The present invention furthermore also relates to substrates coated with a multilayer coating according to the invention.

10

The present invention also relates to a method for coating substrates with at least one radiation-curable coating system (F), in which an elastic coating is provided between the substrate and the at least one radiation-curing coating system (F)

15 intermediate layer (D) with a glass transition temperature (T _g ) of -20 ° C or lower is applied.

The coating can be carried out according to one of the methods mentioned above and the above applies to the radiation-curable coating systems (F) and the 20 elastic intermediate layer (D).

The thickness of such a layer to be hardened as described can be from 0.1 μm to several mm, preferably from 1 to 2000 μm, particularly preferably 5 to 1000 μm, very particularly preferably from 25 10 to 500 μm and in particular from 10 to 250 μm ,

For a given system, the fracture mechanical behavior is determined from the ratio V of the intermediate layer thickness ZS (layer (D)) to the total thickness of the intermediate layer plus the thickness DL of the top coat,

30 i.e. the sum of the thickness of the layers (E) and (F), determines V = ZS / (ZS + DL). The lower the temperatures to which the systems are exposed and the higher the rates of deformation, the greater V must be chosen so that it does not break under mechanical stress. According to the invention

35 gen values V at least 0.05 at temperatures of at least 25 ° C, preferably at least 0.1 at temperatures of at least 0 ° C, particularly preferably at least 0.2 at temperatures of at least -20 ° C and very particularly preferably at least 0, 3 at temperatures of -50 ° C.

40

The multi-layer coatings according to the invention achieve improved adhesion compared to known UV-curable coatings, especially on engineering plastics, and better hardness, elasticity, abrasion resistance and chemical resistance.

45 The multilayer coatings according to the invention are particularly preferably suitable as or in exterior coatings, that is to say those applications which are exposed to daylight, preferably of buildings or parts of buildings, interior coatings, road markings, coatings on vehicles and aircraft. In particular, the multicoat paint systems according to the invention are used as or in automotive clearcoat and topcoat (s), both for the automotive exterior and for the interior.

The multi-layer lacquers according to the invention can intercept cracks occurring in the outer lacquer layer through the intermediate layer (D) present according to the invention in such a way that they do not propagate into the substrate. For this purpose, a plurality of elastic intermediate layers can of course also be incorporated in a multi-layer coating, for example between the layers (E) and (F) and / or between (A) and (C), provided that these layers are contained in the multi-layer coating.

High scratch resistance can be achieved with the multicoat paint systems of the invention.

Unless otherwise stated, ppm and percentages used in this document relate to percentages by weight and ppm.

Examples

The scratch resistance was determined according to the Scotch Brite test as described in DE-Al 199 40 312, page 8, line 64 to page 9, line 5:

A 3 X 3 cm silicon carbide-modified fiber fleece (Scotch Brite SUFN, 3M Germany, 41453 Neuss) is attached to a cylinder as a test specimen. This cylinder presses the nonwoven with 750 g onto the coating and is moved pneumatically over the coating. The path of the deflection is 7 cm. After 10 or 50 double strokes (DH), the gloss (six-fold determination) is measured in the central area of the stress according to DIN 67530, ISO 2813 at an angle of incidence of 60 °. The difference is formed from the gloss values of the coatings before and after the mechanical stresses. The loss of gloss is inversely proportional to the scratch resistance.

The toughness a _cu was measured in accordance with DIN EN ISO 179 / lfü at -50 ° C. The top coat 1 was produced from Laromer® LR 8987 from BASF AG, Ludwigshafen and additives.

The top coat 2 was produced from Laromer® LR 8949 from BASF AG, Ludwigshafen and additives.

The following substrates were used:

Claims

claims

1. Multi-layer coating on a substrate, containing at least one radiation-curable coating system (F) and at least one elastic intermediate layer (D) between the substrate and radiation-curing coating system (F) with a glass transition temperature (T _g ) of -20 ° C or lower (measured in the frequency range up to 1000 Hz).

2. Multi-layer coating according to claim 1, consisting of

(F) at least one radiation-curable coating system,

(E) optionally at least one pigmented and / or layer provided with effect substances,

(D) at least one elastic intermediate layer (D) with a glass transition temperature (T _g ) of -20 ° C or lower,

(C) optionally at least one layer, selected from the group consisting of primer, basecoat, primer, pigmented or effect paint and substrate 2,

(B) optionally at least one elastic intermediate layer, if layer (C) is a substrate 2 and

(A) substrate 1.

Multi-layer coating according to claim 1 or 2, characterized in that the substrates 1 and / or 2 in the layers (A) and / or (C) are selected from the group of paper, plastics and metals.

, Multi-layer coating according to claim 1 or 2, characterized in that the substrates are selected from the group PP (polypropylene), SAN (styrene-acrylonitrile copolymers), PC, PMMA, PBT, PA, ASA (acrylonitrile-styrene-acrylic ester copoly- mere) and ABS (acrylonitrile-butadiene-styrene copolymers), as well as their physical mixtures (blends).

5. Multi-layer coating according to one of the preceding claims, characterized in that the layer thickness of the elastic intermediate layer (D) is 0.5 to 500 microns.

6. Multi-layer coating according to one of the preceding claims, characterized in that at least one compound in the elastic intermediate layer (D) selected from the group comprising thermoplastic elastomers, polyacrylates and poly-iso-butenes.

7. Multi-layer coating according to claim 6, characterized in that at least one compound in the elastic intermediate layer (D) selected from the group comprising styrene-butadiene-styrene (SBS), styrene-isoprene-styrene (SIS), styrene-ethylene / butylene Styrene (SEBS) and styrene-ethylene / propylene-styrene (SEPS) block polymers.

8. substrate coated with a multi-layer coating according to one of the preceding claims.

9. A method for coating substrates with at least one radiation-curable coating system (F), characterized in that an elastic intermediate layer (D) with a glass transition temperature (T _g ) of -20 ° C between the substrate and the at least one radiation-curable coating system (F) or lower is applied.

10. Use of a multi-layer coating according to one of claims 1 to 7 for coating buildings or parts of buildings, interior coatings, coatings on vehicles and aircraft.