EP1526923B1 - 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

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

High scratch resistance is a widespread requirement for paints. For this purpose, for example, in the automotive industry plastic parts are coated with a scratch-resistant clearcoat, which may be on the one hand to thermosetting, so-called. One or two-component PU paints, or on the other preferred to clearcoats, which upon irradiation with actinic Cure radiation. In hard coatings, however, there is often the problem that a micro-crack initiated in the paint propagates very locally defined by the coating in the substrate to which the paint is applied, as in eg DE-A1 199 56 483 is described.

DE-A1 199 56 483 describes lacquered plastic moldings which have on a plastic layer of at least one graft polymer of a rubber-elastic graft with a glass transition temperature T _g below 10 ° C and a graft with a T _g of more than 30 ° C, at least one coating with certain properties. A rubber phase is thus distributed in the substrate.

A disadvantage of the described method is that such graft polymers can bind only insufficiently covalently to the topcoat, since grafting can only be achieved via the volume fraction of the elastomeric component of the blend. In particular, it is important for a high-barrier paint build-up to prevent small microcracks from spreading through a continuous elastomer layer. DE-A1 199 20 801 describes special multi-layer clearcoats in which each clearcoat layer is radiation-curable, whereby a layer is rendered scratch-resistant by inorganic nanoparticles.

DE-A1 100 27 268 describes special multi-layer clearcoats in which the 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 sequentially.

WO 99/26732 describes a process for producing a multilayer coating, in which a coating agent and a clearcoat film are applied to an optionally precoated substrate.

A disadvantage of these cited documents is that even when using the technical teaching disclosed therein, the scratch resistance, especially the problem of cracking in the paint, can not meet today's requirements.

It was therefore an object to develop a coating which has a very high scratch resistance with good adhesion to the substrate with reduced crack propagation into the substrate.

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

A crack formed in a multicoat paint system according to the invention in an exterior paint system (F) does not propagate through the elastic intermediate layer (D) under typical loads described in the applications, so that the substrate on which the multicoat paint system is applied is not damaged and retains its characteristic mechanical properties.

• (F) mindestens ein strahlungshärtbares Lacksystem,
• (E) gegebenenfalls mindestens eine pigmentierte und/oder mit Effektstoffen versehene Schicht,
• (D) mindestens eine elastische Zwischenschicht (D) mit einer Glasübergangstemperatur (T_g) von -20 °C oder niedriger,
• (C) gegebenenfalls mindestens eine Schicht, ausgewählt aus der Gruppe Primer, Basislack, Grundierung, pigmentierter oder mit Effektstoffen versehener Lack und Substrat 2,
• (B) gegebenenfalls mindestens einer elastischen Zwischenschicht, falls Schicht (C) ein Substrat 2 ist sowie
• (A) Substrat 1 mit einer Zähigkeit nach DIN EN ISO 179/1fU bei 23 °C und 50 % Feuchtigkeit von mindestens 20 kJ/m².

Such a multicoat system of the invention may contain further layers. For example, a multi-layer 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 effect-coated layer,
• (D) at least one elastic intermediate layer (D) having 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 / 1fU at 23 ° C and 50% moisture of at least 20 kJ / m ² .

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

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

Plastics are understood to mean the technical plastics known per se to the person skilled in the art with toughness according to. DIN EN ISO 179 / 1fU at 23 ° C and 50% moisture of at least 20, preferably at least 25 kJ / m ² , for example polymers and copolymers containing (meth) acrylic acid esters, vinylaromatic compounds, eg styrene, divinylbenzene, vinyl esters, eg vinyl acetate, halogenated ethylenically unsaturated compounds, for example vinyl chloride, vinylidene chloride, conjugated unsaturated compounds, for example butadiene, isoprene, chloroprene, α, β-unsaturated nitriles, for example acrylonitrile, monounsaturated compounds, for example ethylene, propylene, 1-butene, 2-butene, iso- Butene, cyclic monounsaturated compounds, for example cyclopentene, cyclohexene, N-vinylpyrrolidone, N-vinyllactams, such as N-vinylcaprolactam, vinyl ethers, for example methyl vinyl ether, ethyl vinyl ether, n-propyl vinyl ether, iso-propyl vinyl ether, n-butyl vinyl ether in polymerized form.

Specifically mentioned are polyethylene, polypropylene, polystyrene, polybutadiene, polyesters, 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 or graft copolymers and blends from that.

Particular mention may be made of ABS, AES, AMMA, ASA, EP, EPS, EVA, EVAL, HDPE, LDPE, MABS, MBS, MF, PA, PA6, PA66, PAN, PB, PBT, PBTP, PC, PE, PEC, PEEK , 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 (abbreviated to DIN 7728) and aliphatic polyketones.

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

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

Substrates 1 in layer (A) may also be the same or different, laminated substrates, for example laminated plastics.

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

In each case one or more substrates 1 and / or 2 can 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, then it may preferably be a film, for example a plastic or metal or particularly preferably a plastic film, which may be made of the stated plastics.

Such a film may 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 combined with a further elastic intermediate layer (B) with the substrate (A).

Such an intermediate layer has the same characteristics as the intermediate layer (D) (see below) and may be different from or the same.

Typical thicknesses of the layer (B) range from 0.1 to 1000 microns, preferably 0.5 to 500 microns, more preferably from 1 to 250 microns and most preferably from 1 to 100 microns.

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

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

As color and / or effect paints in the layer (C) and / or (E) are basically all customary for this purpose and known in the art paints into consideration. These may be curable physically, thermally, with actinic radiation or thermally and with actinic radiation (dual-cure). They may be conventional basecoats, waterborne basecoats, substantially solventborne and waterborne liquid basecoat materials (100% systems), substantially solventborne and waterborne solid basecoats (pigmented powder coatings), or substantially solventless pigmented powder coating dispersions (powder slurry basecoats). They can be thermally or dual-cure, and self or externally crosslinked.

These may be one or more, preferably 1 to 3, more preferably 1 to 2 and most preferably a color and / or effect paint.

In the context of the present invention, substantially solvent-free means that the relevant coating material has a residual content of volatile solvents of <2.0% by weight, preferably <1.5% by weight and particularly preferably <1.0% by weight , It is of very particular advantage if the residual content is below the gas chromatographic detection limit.

With particular preference, water-based paints are used in the multicoat paint systems according to the invention, as disclosed in the patent applications EP 0 089 497 A1 . EP 0 256 540 A1 . EP 0 260 447 A1 . EP 0 297 576 A1 . WO 96/12747 . EP 0 523 610 A1 . EP 0 228 003 A1 . EP 0 397 806 A1 . EP 0 574 417 A1 . EP 0 531 510 A1 . EP 0 581211 A1 . EP 0 708 788 A1 . EP 0 593 454 A1 . DE-A-43 28 092 A1 . EP 0 299 148 A1 . EP 0 394 737 A1 . EP 0 590 484 A1 . EP 0 234 362 A1 . EP 0 234 361 A1 . EP 0 543 817 A1 . W095 / 14721 . EP 0 521 928 A1 . EP 0 522 420 A1 . EP 0 522 419 A1 . EP 0 649 865 A1 . EP 0 536 712 A1 . EP 0 596 460 A1 . EP 0 596 461 A1 . EP 0 584 818 A1 . EP 0 669 356 A1 . EP 0 669 356 A1 . EP 0 634 431 A1 . EP 0 678 536 A1 . EP 0 354 261 A1 . EP 0 424 705 A1 . WO 97/49745 . WO 97/49747 . EP 0 401 565 A1 or EP 0 817 684 , Column 5, lines 31 to 45, are known.

The color and / or effect paints described above can serve 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 multicoat color and / or effect coating. Functions of this kind are, in particular, the protection against corrosion, the adhesion promotion, the absorption of mechanical energy and the color and / or effect. Above all, the combination effect layer serves the absorption of mechanical energy as well as the color and / or effect at the same time; it thus fulfills the functions of a primer coat or antistonechip primer and a base coat. In addition, the combination effect layer moreover still has anticorrosive effect and / or adhesion-promoting action.

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

The paints which can be used in the multicoat paint systems according to the invention can contain color and / or effect pigments. As coloring pigments all customary pigments of organic or inorganic nature are suitable. 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 characterized in particular by a platelet-like structure. Examples of effect pigments are:
Metal pigments, eg of aluminum, copper or other metals; Interference pigments, such as metal oxide-coated metal pigments, eg titanium dioxide-coated or mixed oxide-coated aluminum, coated mica, such as titanium dioxide-coated mica and graphite effect pigments. Advantageously, for example, to improve the hardness, UV-curable pigments and optionally also fillers can be used. These are radiation-curable compounds, For example, acrylic-functional silanes, coated pigments / fillers, which can thus be included in the radiation hardening process.

In the intermediate layer (D) according to the invention at least one compound having a glass transition temperature (Tg) of -20 ° C or lower, preferably - 30 ° C or lower, more preferably -40 ° C or lower, most preferably -50 ° C or lower and especially -60 ° C or lower.

The glass transition temperature Tg was determined using flexural vibration tests (according to DIN 53440 T1 to T3) at a frequency of 0 to 1000 Hz, preferably 100 to 1000 Hz. At the same time, the flexural vibration provides the Tg, which is important from a fracture mechanics point of view, at high deformation rates (frequencies).

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

For example, rubber-containing polymers, ac-resins, polyacrylates having a Tg as indicated and poly-iso-butylenes can be used as compounds in the elastic intermediate layer. Suitable rubber-containing polymers are, for example, thermoplastic elastomers. Such thermoplastic elastomers usually contain at least one elastomeric component (soft domain) and at least one thermoplastic component (hard domain), which may be joined together as a blend, vulcanizate or block polymer, preferably as a block polymer.

The elastomeric component may 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), preferably polybutadiene, polyisoprene, ethylene / propylene or ethylene / propylene / diene rubber, more preferably polybutadiene or polyisoprene rubber, and most preferably polybutadiene rubber.

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

The thermoplastic component may 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, ASA, PMMA or polystyrene act, preferred are polystyrene and polypropylene and particularly preferred is polystyrene.

The thermoplastic component generally has (in a block polymer based on the block) molar masses of up to 50,000 g / mol, preferably 5,000 to 40,000 and more 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 having at least one elastomeric block Y and at least one thermoplastic block Z of the general formula Z (-YZ) m, where m is a positive integer from 1 to 10, preferably 1 to 5, particularly preferably 1 to 3, completely 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 may be linear or branched, e.g. star-shaped, constructed, preferably linear.

Particularly preferred thermoplastic elastomers are styrene oligoblock polymers, very particular preference is given to styrene triblock polymers in which the thermoplastic block consists predominantly, preferably completely, of styrene. Particular preference is given to 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 still with reactive comonomers such as Maleic anhydride can be functionalized. The thermoplastic elastomers may further be fully or partially hydrogenated.

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

Furthermore, the thermoplastic elastomers which can be used according to the invention can be mixed with mineral oil, polystyrene, polyolefins, fillers or additives, such as antioxidants, UV stabilizers or antiozonants.

Most preferably, Kraton® Kraton® Kraton® grades are used as thermoplastic elastomers. LLC, Houston, Texas, USA and Vector® trademarks of Dexco Polymer, Houston, Texas, USA. Particular preference is given to the Kraton D and G marks, preferably the Kraton D marks and particularly preferably Kraton D1101, D1118, D4150, D1112, D-KS 225 ES, D1102, D1116, D1186 and D4123, and also the Brands 7400, 8508 and 2518.

Suitable polyacrylates are (co) polymers having a Tg as indicated.

• Hauptmonomer 50 - 98 Gew%
• Nebenmonomer 10 - 40 Gew%
• Funktionalisiertes Monomer 0 - 20 Gew%,

mit der Maßgabe daß die Summe immer 100 Gew% beträgt.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.

Therein, main monomers are, for example, methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, n-butyl (meth) acrylate, iso-butyl (meth) acrylate, sec-butyl (meth) acrylate, (Meth) acrylic acid n-pentyl ester, (meth) acrylic acid iso-pentyl 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, n-heptyl (meth) acrylate, n-octyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, decyl (meth) acrylate, (meth) acrylic acid decyl ester, (meth) acrylic acid dodecyl ester, (meth) acrylic acid 2-methoxyethyl ester, (meth) acrylic acid 2-ethoxyethyl ester, (meth) acrylic acid 4-methoxybutyl ester, (meth) acrylic acid 2- (2'-methoxyethoxy) ethyl ester, (meth) acrylic acid 2-hydroxyethyl ester, (meth) acrylic acid 2-hydroxypropyl ester, (meth) acrylic acid 3-hydroxypropyl ester, (meth) acrylic acid 4-hydroxybutyl ester, ethylene glycol ol (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, trimethylolpropane 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 vinyl ether, iso- propyl vinyl ether, n Butyl vinyl ether, sec- butyl vinyl ether, iso -butyl 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 as minor monomers are e.g.

(Meth) acrylic acid isobornyl ester, tridecyl (meth) acrylate, (meth) acrylic acid lauryl ester, (meth) acrylic acid stearyl ester, (meth) acrylic acid 10-cyclohexylundecylester, (meth) acrylic acid 2-cyanoethylester, (meth) acrylic acid 2-dimethylaminoethylester , Glycidyl (meth) acrylate, (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, diiso-propyl fumarate, di-n-butyl fumarate, di-fumarate fumarate, diammonium fumarate, fumaric di-2- ethylbutylester, di-n-octyl fumarate, di-2-ethylhexyl fumarate, dodecyl fumarate, bis (2-hydroxyethyl) fumarate, dibutyl maleate, di-2-ethylhexyl maleate, di (2-hydroxyethyl) maleate, maleic acid nitrile, malononitrile, vinyl valerate, divinyl ether , 2-chloroethyl vinyl ether, α-propiolac clay, δ-valerolactone, ε-caprolactone, N-vinylformamide, N-vinylacetamide, N-vinyl-N-methylformamide, N-vinyl-N-methylacetamide, allylacetic acid, vinylacetic acid and mixtures thereof.

Functionalized monomers are, for example, those which carry carboxyl, hydroxyl, epoxy, allyl, carboxamide, amine, isocyanate, hydroxymethyl, methoxymethyl or silyloxy groups. These may be, for example, (meth) acrylic acid, (meth) acrylic acid formate, (meth) acrylic acid hydroxymethyl ester, (meth) acrylic acid benzophenone glycidyl ester, (meth) acrylic acid 2-sulfoethyl ester, (meth) acrylamide, N-methylol (meth) acrylamide, fumaric acid, fumaric acid mono- iso-propyl, n hexyl fumaric acid, fumaric acid amide, fumaric acid diamide, fumaronitrile, fumaronitrile, crotonic acid, Crotonsäureglycidylester, itaconic acid, itaconic acid, itaconic anhydride, citraconic acid, Citraconsäurehalbester, citraconic anhydride, succinic acid, maleic acid, monomethyl maleate, monoethyl maleate, Maleic acid monobutyl ester, maleic anhydride, maleic acid amide, maleic acid diamide, N-methylolmaleic acid amide, vinylsuccinimide, vinylimidazole, 2-vinylpyridine, 4-vinylpyridine, N-vinylpyrrolidone, N-vinylpiperidone, N-vinylcaprolactam, sodium vinylsulfonate, tetraallyloxyethane, diallyl phthalate, diallyl succinate, tetraallylethane, tetraallyloxysilane, allyl glycidyl ether, Triallylcyanurat, triallyl isocyanurate, diketene, monoethylenically unsaturated carboxylic acids having 3 to 8 carbon atoms and their water-soluble alkali metal, alkaline earth metal or ammonium salts such as: acrylic acid, methacrylic acid, dimethylacrylic acid, ethacrylic acid, maleic acid, citraconic acid, methylenemalonic acid, crotonic acid, fumaric acid, mesaconic acid or itaconic acid as well as mixtures thereof.

In order to obtain the stated 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 useful (co) polymers, optionally before further crosslinking, (determined by gel permeation chromatography using polystyrene as standard and tetrahydrofuran as eluent) is, for example, between 200,000 and 1,500,000 g / mol, preferably between 250,000 and 1,200,000 preferably between 300,000 and 900,000.

The gel content of the useful (co) polymers, i. the proportion of an adhesive film which is soluble at THF for 24 hours at room temperature is between 30 and 70, preferably between 30 and 60 and more preferably between 40 and 60% by weight.

Particularly suitable according to the invention are radiation-crosslinkable polyacrylates.

These are polyacrylates which can be crosslinked by active energy irradiation. These adhesives generally contain poly (meth) acrylate, preferably polyacrylate, optionally in combination with aliphatic or aromatic epoxy resins, urethanes, polyesters or polyethers. Preference is given to using epoxy resins, aliphatic, aromatic or mixed aliphatic-aromatic urethanes.

The crosslinking takes place by active energy irradiation, but it can also be crosslinked via a second curing mechanism or other curing mechanisms (dual cure), for example by moisture, oxidation or heat, preferably by heat, for example at the stated curing temperature.

Furthermore, crosslinking monomers can be admixed, e.g. 1,3-Butylene glycol di (meth) acrylate, tripropylene glycol di (meth) acrylate, trimethylolpropane triacrylate or pentaerythritol tetraacrylate.

For crosslinking by UV light, a photoinitiator can be added.

However, the photoinitiator can also be bound to the poly (meth) acrylate. The photoinitiator may then be, for example, cyclic imide structures, for example maleimide or maleimide derivatives, benzo or acetophenone groups. The latter are eg in the EP-B1 377 199 , Page 3, line 14 to page 13, line 45, as well as in the EP-A 395 987 , Page 3, line 24 to page 5, line 42 and are hereby incorporated by reference.

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

As poly-isobutene (PIB) or modified polyisobutene, for example, the reaction products of PIB with maleic anhydride, hydroformylated PIB, hydroformylated and then hydrogenated PIB and hydroformylated and then aminated hydrogenated PIB, Glissopal® or Oppanol® brands BASF AG, Polybutene® brands from BP, the Infineum® C series from Infineum 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, which have a molecular weight of about 200 to 1,000,000, preferably the Oppanole® B10, 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, V500, V640, V700, V90 and 1000, Infineum® C9945, C9925, C9950, C9970, C9980, C9983, C9984, C9913, C9922, C9907, C9924 and C9995 and Vistanex® 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 can be used, for example 1 to 5, preferably 1 to 4, more preferably 1 to 3 and most preferably 1 to 2 compounds. In particular, a compound 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; they may be, for example, the radiation-curable clearcoat or topcoat materials known to the person skilled in the art for such purposes. They usually contain at least one free-radically and / or cationically polymerizable group, preferably they are free-radically polymerizable.

Polymerizable groups may be those having 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, vinyllactams, vinyl esters, (meth) acrylic esters or acrylonitriles.

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

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

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

• (F1) at least one polymerizable compound having a plurality of copolymerizable, ethylenically unsaturated groups,
• (F2) optionally reactive diluents,
• (F3) optionally photoinitiator as well
• (F4) if appropriate, further typical coatings additives.

As compounds (F1), radiation-curable, free-radically polymerizable compounds having plural, i. at least two copolymerizable, ethylenically unsaturated groups into consideration.

It is preferable that compounds (F1) are vinyl ether or (meth) acrylate compounds, particularly preferred are 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.

Particular preference is given to those compounds (F1) having a content of ethylenically unsaturated double bonds of 0.1-0.7 mol / 100 g, very particularly preferably 0.2-0.6 mol / 100 g. The number average molecular weight M _{n of} the compounds (F1) is, unless stated otherwise, preferably below 15,000, more preferably 300-12,000, most preferably 400-5000 and especially 500-3000 g / mol (determined by gel permeation chromatography with polystyrene as standard and tetrahydrofuran as eluent).

As (meth) acrylate compounds may be mentioned (meth) acrylic acid esters and in particular acrylic acid esters and vinyl ethers of polyfunctional alcohols, in particular those which contain no further functional groups or at most ether groups in addition to the hydroxyl groups. Examples of such alcohols are e.g. bifunctional alcohols such as ethylene glycol, propylene glycol and their more highly condensed species, 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-1,5-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, ditrimethylolpropane, dipentaerythritol, sorbitol, Mannitol and the corresponding alkoxylated, in particular ethoxylated and / or propoxylated alcohols.

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

Other suitable (meth) acrylate compounds are polyester (meth) acrylates, which are the (meth) acrylic esters or vinyl ethers of polyesterols.

Suitable polyesterols are, for example, those which can be prepared by esterification of polycarboxylic acids, preferably dicarboxylic acids, with polyols, preferably diols. The starting materials for such hydroxyl-containing polyester are known in the art. Succinic acid, glutaric acid, adipic acid, sebacic acid, o-phthalic acid, tetrahydrophthalic acid, terephthalic acid, their isomers and hydrogenation products and also esterifiable derivatives, such as anhydrides or dialkyl esters of the acids mentioned, may preferably be used as dicarboxylic acids. Suitable polyols are the abovementioned alcohols, preferably ethylene glycol, 1,2-propylene glycol and 1,3-butanediol, 1,4-hexanediol, 1,6-hexanediol, neopentyl glycol, cyclohexanedimethanol, 2,2-bis (4-hydroxycyclohexyl) propane and Polyglycols of the type of ethylene glycol and propylene glycol into consideration.
Suitable radiation-curable compounds (F1) include, for example, unsaturated polyester resins which consist essentially of polyols, in particular diols, and polycarboxylic acids, in particular dicarboxylic acids, one of the esterification components containing a copolymerizable, ethylenically unsaturated group. For example, these are maleic acid, fumaric acid or maleic anhydride.
Polyester (meth) acrylates can be used in several stages or in one stage, such as in EP-A 279 303 described, be prepared from (meth) acrylic acid, polycarboxylic acid and polyol.

Furthermore, compounds (F1) may be e.g. urethane or epoxy (meth) acrylates or vinyl ethers.

Urethane (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. In addition, urethane (meth) acrylates dispersible in water without the addition of emulsifiers additionally contain ionic and / or nonionic hydrophilic groups which are present, for example. be incorporated by structural components such as hydroxycarboxylic acids in the urethane.

• (F1-a) mindestens ein organisches aliphatisches, aromatisches oder cycloaliphatisches Di- oder Polyisocyanat,
• (F1-b) mindestens eine Verbindung mit mindestens einer gegenüber Isocyanat reaktiven Gruppe und mindestens einer radikalisch polymerisierbaren ungesättigten Gruppe und
• (F1-c) gegebenenfalls mindestens eine Verbindung mit mindestens zwei gegenüber Isocyanat reaktiven Gruppen.

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

• (F1-a) at least one organic aliphatic, aromatic or cycloaliphatic di- or polyisocyanate,
• (F1-b) at least one compound having at least one isocyanate-reactive group and at least one free-radically polymerizable unsaturated group and
• (F1-c) optionally at least one compound having at least two isocyanate-reactive groups.

Suitable components (F1-a) are, for example, aliphatic, aromatic and cycloaliphatic di- and polyisocyanates having an NCO functionality of at least 1.8, preferably 1.8 to 5 and more preferably 2 to 4, and also their isocyanurates, biurets, allophanates and uretdione.

The diisocyanates are preferably isocyanates having 4 to 20 C atoms. Examples of conventional 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, tetramethylxylylene diisocyanate, trimethylhexane diisocyanate or tetramethylhexane diisocyanate, cycloaliphatic diisocyanates such as 1,4-, 1,3- or 1,2-diisocyanatocyclohexane, 4,4'- or 2,4'-di (isocyanatocyclohexyl) methane, 1-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 also aromatic diisocyanates such as tolylene 2,4- or 2,6-diisocyanate and isomer mixtures thereof, m- or p-xylylene diisocyanate, 2,4'- or 4,4'-diisocyanatodiphenylmethane and their mixtures of isomers, 1,3- or 1,4-phenylenediisocyanate, 1-chloro-2,4-phenylenediisocyanate, 1,5-naphthylenediisocyanate, diphenyl-4,4'- diiso cyanate, 4,4'-diisocyanato-3,3'-dimethyldiphenyl, 3-methyldiphenylmethane-4,4'-diisocyanate, tetramethylhylylene diisocyanate, 1,4-diisocyanatobenzene or diphenyl ether-4,4'-diisocyanate.

There may also be mixtures of said diisocyanates.

Preference is given to hexamethylene diisocyanate, 1,3-bis (isocyanatomethyl) cyclohexane, isophorone diisocyanate and di (isocyanatocyclohexyl) methane.

Suitable polyisocyanates are polyisocyanates containing isocyanurate groups, uretdione diisocyanates, polyisocyanates containing biuret groups, polyisocyanates containing oxadiazinetrione groups, uretonimine-modified polyisocyanates of straight-chain or branched C ₄ -C ₂₀ -alkylene diisocyanates, cycloaliphatic diisocyanates having a total of from 6 to 20 carbon atoms or aromatic diisocyanates having a total of 8 to 20 carbon atoms or mixtures thereof.

The usable di- and polyisocyanates preferably have a content of isocyanate groups (calculated as NCO, molecular weight = 42) of 10 to 60% by weight, based on the di- and polyisocyanate (mixture), preferably 15 to 60% by weight and more preferably 20 to 55% by weight.

Preferred are aliphatic or cycloaliphatic di- and polyisocyanates, e.g. the abovementioned aliphatic or cycloaliphatic diisocyanates, or mixtures thereof.

1. 1) Isocyanuratgruppen aufweisende Polyisocyanate von aromatischen, aliphatischen und/oder cycloaliphatischen Diisocyanaten. Besonders bevorzugt sind hierbei die entsprechenden aliphatischen und/oder cycloaliphatischen Isocyanato-Isocyanurate und insbesondere die auf Basis von Hexamethylendiisocyanat und Isophorondiisocyanat. Bei den dabei vorliegenden Isocyanuraten handelt es sich insbesondere um Trisisocyanatoalkyl- bzw. Tris-isocyanatocycloalkyl-Isocyanurate, welche cyclische Trimere der Diisocyanate darstellen, oder um Gemische mit ihren höheren, mehr als einen Isocyanuratring aufweisenden Homologen. Die Isocyanato-Isocyanurate haben im allgemeinen einen NCO-Gehalt von 10 bis 30 Gew.-%, insbesondere 15 bis 25 Gew.-% und eine mittlere NCO-Funktionalität von 3 bis 4,5.
2. 2) Uretdiondiisocyanate mit aromatisch, aliphatisch und/oder cycloaliphatisch gebundenen Isocyanatgruppen, vorzugsweise aliphatisch und/oder cycloaliphatisch gebundenen und insbesondere die von Hexamethylendiisocyanat oder Isophorondiisocyanat abgeleiteten. Bei Uretdiondiisocyanaten handelt es sich um cyclische Dimerisierungsprodukte von Diisocyanaten. Die Uretdiondiisocyanate können in den Zubereitungen als alleinige Komponente oder im Gemisch mit anderen Polyisocyanaten, insbesondere den unter 1) genannten, eingesetzt werden.
3. 3) Biuretgruppen aufweisende Polyisocyanate mit aromatisch, cycloaliphatisch oder aliphatisch gebundenen, bevorzugt cycloaliphatisch oder aliphatisch gebundenen Isocyanatgruppen, insbesondere Tris(6-isocyanatohexyl)biuret oder dessen Gemische mit seinen höheren Homologen. Diese Biuretgruppen aufweisenden Polyisocyanate weisen im allgemeinen einen NCO-Gehalt von 18 bis 22 Gew.-% und eine mittlere NCO-Funktionalität von 3 bis 4,5 auf.
4. 4) Urethan- und/oder Allophanatgruppen aufweisende Polyisocyanate mit aromatisch, aliphatisch oder cycloaliphatisch gebundenen, bevorzugt aliphatisch oder cycloaliphatisch gebundenen Isocyanatgruppen, wie sie beispielsweise durch Umsetzung von überschüssigen Mengen an Hexamethylendiisocyanat oder an Isophorondiisocyanat mit mehrwertigen Alkoholen wie z.B. Trimethylolpropan, Neopentylglykol, Pentaerythrit, 1,4-Butandiol, 1,6-Hexandiol, 1,3-Propandiol, Ethylenglykol, Diethylenglykol, Glycerin, 1,2-Dihydroxypropan oder deren Gemische erhalten werden können. Diese Urethan- und/oder Allophanatgruppen aufweisenden Polyisocyanate haben im allgemeinen einen NCO-Gehalt von 12 bis 20 Gew.-% und eine mittlere NCO-Funktionalität von 2,5 bis 3.
5. 5) Oxadiazintriongruppen enthaltende Polyisocyanate, vorzugsweise von Hexamethylendiisocyanat oder Isophorondiisocyanat abgeleitet. Solche Oxadiazintriongruppen enthaltenden Polyisocyanate sind aus Diisocyanat und Kohlendioxid herstellbar.
6. 6) Uretonimin-modifizierte Polyisocyanate.

Further preferred

1. 1) isocyanurate-containing polyisocyanates of aromatic, aliphatic and / or cycloaliphatic diisocyanates. Particular preference is given here to the corresponding aliphatic and / or cycloaliphatic isocyanato-isocyanurates and in particular those based on hexamethylene diisocyanate and isophorone diisocyanate. The isocyanurates present are, in particular, trisisocyanatoalkyl or trisisocyanatocycloalkyl isocyanurates, which are cyclic trimers of the diisocyanates, or mixtures with their higher homologs having more than one isocyanurate ring. The isocyanato-isocyanurates generally have an NCO content of 10 to 30 wt .-%, in particular 15 to 25 wt .-% and an average NCO functionality of 3 to 4.5.
2. 2) uretdione diisocyanates having aromatic, aliphatic and / or cycloaliphatic bound isocyanate groups, preferably aliphatically and / or cycloaliphatically bonded 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. 3) biuret polyisocyanates having aromatic, cycloaliphatic or aliphatic bound, preferably cycloaliphatic or aliphatic bound isocyanate groups, in particular tris (6-isocyanatohexyl) biuret or mixtures thereof with its higher homologues. These biuret polyisocyanates generally have an NCO content of 18 to 22 wt .-% and an average NCO functionality of 3 to 4.5.
4. 4) polyisocyanates containing urethane and / or allophanate groups with aromatic, aliphatic or cycloaliphatic bound, preferably aliphatic or cycloaliphatic bound Isocyanate groups, as obtained, for example, by reacting excess amounts of hexamethylene diisocyanate or of isophorone diisocyanate with polyhydric alcohols, for example 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 urethane and / or allophanate-containing polyisocyanates generally have an NCO content of 12 to 20 wt .-% and an average NCO functionality of 2.5 to 3.
5. 5) oxadiazinetrione-containing polyisocyanates, preferably derived from hexamethylene diisocyanate or isophorone diisocyanate. Such oxadiazinetrione-containing polyisocyanates can be prepared from diisocyanate and carbon dioxide.
6. 6) Uretonimine-modified polyisocyanates.

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

Suitable components (F1-b) are compounds which carry at least one isocyanate-reactive group and at least one free-radically polymerizable group.

Isocyanate-reactive groups can be, for example, -OH, -SH, -NH ₂ and -NHR ¹ , where R ^{1 is} hydrogen or an alkyl group containing 1 to 4 carbon atoms, such as, for example, methyl, ethyl, n-propyl, iso -propyl, n- Butyl, iso- butyl, sec- butyl or tert- butyl, means.

Components (F1-b) can be, for example, 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 ethers with diols or polyols, preferably 2 to 20 C atoms and at least two hydroxy groups, such as ethylene glycol, diethylene glycol, triethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,1-dimethyl-1,2-ethanediol, dipropylene glycol, triethylene glycol, tetraethylene glycol, pentaethylene glycol, tripropylene glycol, 1,4 Butanediol, 1,5-pentanediol, neopentyl glycol, 1,6-hexanediol, 2-methyl-1,5-pentanediol, 2-ethyl-1,4-butanediol, 1,4-dimethylolcyclohexane, 2,2-bis (4 -hydroxycyclohexyl) propane, glycerol, trimethylolethane, trimethylolpropane, trimethylolbutane, pentaerythritol, ditrimethylolpropane, erythritol, sorbitol, poly-THF having a molecular weight between 162 and 2000, poly-1,3-propanediol having a molecular weight between 134 and 400 or polyethylene glycol with a molecular weight between 238 and 458. Furthermore, esters or amides of (meth) acrylic acid with amino alcohols z. B. 2-aminoethanol, 2- (methylamino) ethanol, 3-amino-1-propanol, 1-amino-2-propanol or 2- (2-aminoethoxy) ethanol, 2-mercaptoethanol or polyaminoalkanes, such as ethylenediamine or diethylenetriamine, or Vinylacetic acid are used.

Also suitable are unsaturated polyether or polyesterols or polyacrylate polyols having an average OH functionality of 2 to 10.

Examples of amides of ethylenically unsaturated carboxylic acids with amino alcohols are hydroxyalkyl (meth) acrylamides such as N-hydroxymethylacrylamide, N-hydroxymethylmethacrylamide, N-hydroxyethylacrylamide, N-hydroxymethylmethacrylamide, 5-hydroxy-3-oxa-pentyl (meth) acrylamide, N-hydroxyalkylcrotonamides such as N Hydroxymethylcrotonamide or N-hydroxyalkylmaleimides such as N-hydroxyethylmaleimide.

Preference is given to using 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, 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 and 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-hydroxypropyl (meth) acrylamide. Particularly preferred are 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, 2- or 3-hydroxypropyl acrylate, 1,4-butanediol monoacrylate and 3- (acryloyloxy) -2-hydroxypropyl methacrylate.

Suitable components (F1-c) are compounds which have at least two isocyanate-reactive groups, for example -OH, -SH, -NH ₂ or -NHR ² , where R ² independently of one another is hydrogen, methyl, ethyl, isopropyl , n-propyl, n-butyl, iso- butyl, sec -butyl or tert -butyl.

These are preferably diols or polyols, such as hydrocarbon diols having from 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-cyclohexanediol, Cyclooctanediol, norbornanediol, pinanediol, decalindiol, 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 polyhydric alcohols, secondary or primary amino alcohols, such as ethanolamine, diethanolamine, monopropanolamine, dipropanolamine, etc., or thioalcohols, such as thioethylene glycol.

Also conceivable are diethylene glycol, triethylene glycol, dipropylene glycol, tripropylene glycol, neopentyl glycol, pentaerythritol, 1,2- and 1,4-butanediol, 1,5-pentanediol, 2-methyl-1,5-pentanediol, 2-ethyl-1,4- butanediol, 1,2-, 1,3- and 1,4-dimethylolcyclohexane, 2,2-bis (4-hydroxycyclohex-yl) propane, glycerol, trimethylolethane, trimethylolpropane, trimethylolbutane, dipentaerythritol, ditrimethylolpropane, erythritol and sorbitol, 2-aminoethanol, 3-amino-1-propanol, 1-amino-2-propanol or 2- (2-aminoethoxy) ethanol, bisphenol A, or butanetriol.

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

Particularly suitable here are the cycloaliphatic diols, e.g. Bis- (4-hydroxycyclohexane) isopropylidene, tetramethylcyclobutanediol, 1,2-, 1,3- or 1,4-cyclohexanediol, cyclooctanediol or norbornanediol.

The polyurethanes which can be used according to the invention are obtained by reacting components (F1-a), (F1-b) and (F1-c) with one another.

Here, the molar composition (F1-a) (F1-b): (F1-c) per 3 moles of reactive isocyanate groups in (F1-a) is usually as follows: (F1-b) 1.5-3.0 , preferably 2.0-2.9, particularly preferably 2.0-2.5 and in particular 2.0-2.3, moles of isocyanate-reactive groups and

(F1-c) 0-1.5, preferably 0.1-1.0, particularly preferably 0.5-1.0 and especially 0.7-1.0 moles of isocyanate-reactive groups.

When using the polyurethanes in aqueous systems, essentially all the isocyanate groups present are preferably reacted.

The formation of the adduct of isocyanate group-containing compound and the compound containing isocyanate-reactive groups is generally carried out by mixing the components in any order, optionally at elevated temperature.

In this case, the compound containing isocyanate-reactive groups is preferably added to the compound containing isocyanate groups, preferably in several steps.

The isocyanate group-containing compound is more preferably initially introduced, and the compounds containing isocyanate-reactive groups are added. In particular, the isocyanate group-containing compound (F1-a) is initially introduced and then (F1-b) added. Subsequently, optionally desired further components can be added.

In general, the reaction is carried out at temperatures between 5 and 100 ° C, preferably between 20 to 90 ° C and more preferably between 40 and 80 ° C and in particular between 60 and 80 ° C.

Preference is given to work under anhydrous conditions.

Anhydrous here means that the water content in the reaction system is not more than 5% by weight, preferably not more than 3% by weight, and more 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 may also be carried out in the presence of an inert solvent, e.g. Acetone, iso-butyl methyl ketone, toluene, xylene, butyl acetate or ethoxyethyl acetate. Preferably, however, the reaction is carried out in the absence of a solvent.

The urethane (meth) acrylates preferably have a number-average molecular weight M _{n of} from 500 to 20,000, in particular from 750 to 10,000, more preferably from 750 to 3,000 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 from 1 to 5, particularly preferably from 2 to 4, mol of vinyl ether groups per 1000 g of urethane vinyl ether.

Epoxy (meth) acrylates are obtainable by reacting epoxides with (meth) acrylic acid. Suitable epoxides are, for example, epoxidized olefins, aromatic glycidyl ethers or aliphatic glycidyl ethers, preferably those of aromatic or aliphatic glycidyl ethers.

Epoxidized olefins may be, for example, ethylene oxide, propylene oxide, isobutylene oxide, 1-butene oxide, 2-butene oxide, vinyl oxirane, styrene oxide or epichlorohydrin. Preferred are ethylene oxide, propylene oxide, isobutylene oxide, vinyl oxirane, styrene oxide or epichlorohydrin, particularly preferably ethylene oxide, propylene oxide or epichlorohydrin and most 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 # [13446-85-0]), tris [4- (2,3-) epoxypropoxy) phenyl] methane isomers (CAS No. [66072-39-7]), phenol based epoxy novolacs (CAS No. [9003-35-4]) and cresol based epoxy novolacs (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-tetrakis [4- (2,3-epoxypropoxy) phenyl] ethane (CAS No. [27043] 37-4]), diglycidyl ethers of polypropylene glycol (α, ω-bis (2,3-epoxypropoxy) poly (oxypropylene) (CAS No. [16096-30-3]) and 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} from 340 to 20,000, particularly preferably from 500 to 10,000 g / mol and very particularly preferably from 750 to 3,000 g / mol; the content of (meth) acrylic or vinyl ether groups is preferably 1 to 5, more 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 contain on average preferably 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, more preferably less than 1500 g / mol, more preferably less than 800 g / mol (determined by gel permeation chromatography with polystyrene as standard, solvent tetrahydrofuran).

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

In a similar manner, vinyl ether carbonates are obtainable by reacting a hydroxyalkyl vinyl ether with carbonic acid esters and optionally dihydric alcohols.

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

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

Suitable hydroxyl-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 hydroxyl-containing vinyl ethers are, for example, 2-hydroxyethyl vinyl ether and 4-hydroxybutyl vinyl ether.

worin R für H oder CH₃ , X für eine C₂-C₁₈ Alkylengruppe und n für eine ganze Zahl von 1 bis 5, vorzugsweise 1 bis 3 steht.Particularly preferred carbonate (meth) acrylates are those of the formula:

wherein R is H or CH ₃ , X is a C ₂ -C ₁₈ 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 -C ₁₀ -alkylene, for example 1,2-ethylene, 1,2-propylene, 1,3-propylene, 1,4-butylene or 1,6-hexylene, particularly preferred for C ₄ - to C ₈ -alkylene. Most preferably, X is C ₆ alkylene.

Preferably, they are aliphatic carbonate (meth) acrylates.

Furthermore, (meth) acrylates or vinyl ethers of polyether polyols can also be used as radiation-curable compounds (F1). These may be monohydric or preferably polyhydric polyether alcohols containing on average from 2 to 70, preferably from 2 to 60, polyalkylene oxide units per molecule, as are obtainable in a manner known per se by alkoxylation of suitable starter molecules. For the preparation of these polyether alcohols, any monohydric or polyhydric alcohols can be used as starter molecules.

Suitable for the alkoxylation alkylene oxides are ethylene oxide, propylene oxide, butylene oxide, iso- butylene oxide and vinyloxirane, which can be used in any order or as a mixture in the alkoxylation reaction.

Suitable starter molecules are, for example, trimethylolpropane, trimethylolethane, neopentyl glycol, pentaerythritol, glycerol, 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.

Vinyl ether group-containing polyether alcohols are obtained, for example, by reacting hydroxyalkyl vinyl ethers with alkylene oxides.

(Meth) acrylic acid group-containing polyether alcohols can be obtained, for example, by transesterification of (meth) acrylic esters with the polyether alcohols, by esterification of the polyether alcohols with (meth) acrylic acid or by using hydroxyl-containing (meth) acrylates as described above under (F1-b).

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

Furthermore, as polyether poly-THF having a molecular weight between 162 and 2000 and poly-1,3-propanediol having a molecular weight between 134 and 1178 can be used.

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

Compounds (F1) are often used in admixture 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.

Mention may be made, for example, of C ₁ -C ₂₀ -alkyl (meth) acrylates, vinylaromatics having up to 20 carbon atoms, vinyl esters of carboxylic acids containing up to 20 carbon atoms, ethylenically unsaturated nitriles, vinyl ethers of alcohols containing from 1 to 10 carbon atoms, α, β-unsaturated carboxylic acids and their anhydrides and aliphatic hydrocarbons having 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 having a C ₁ -C ₁₀ -alkyl radical, such as methyl methacrylate, methyl acrylate, n-butyl acrylate, ethyl acrylate and 2-ethylhexyl acrylate.

In particular, mixtures of (meth) acrylic acid alkyl esters are also suitable.

Vinyl esters of carboxylic acids having 1 to 20 carbon 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 are e.g. Vinyltoluene, α-butylstyrene, 4-n-butylstyrene, 4-n-decylstyrene and preferably styrene into consideration.

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.

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

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

As photoinitiators (F3) it is possible to use photoinitiators known to the person skilled in the art, for example those in " Advances in Polymer Science ", Volume 14, Springer Berlin 1974 or in KK Dietliker, Chemistry and Technology of UV and EB Formulation for Coatings, Inks and Paints, Volume 3; Photoinitiators for Free Radical and Cationic Polymerization, PKT Oldring (Eds), SITA Technology Ltd, London s.

Suitable examples include mono- or bisacylphosphine oxides such as Irgacure® 819 (bis (2,4,6-trimethylbenzoyl) phenylphosphine oxide), as used, for example, in US Pat EP-A 7 508 . EP-A 57 474 . DE-A 196 18 720 . EP-A 495 751 or EP-A 615 980 are described, for example, 2,4,6-trimethylbenzoyldiphenylphosphine oxide (Lucirin ^® TPO), ethyl 2,4,6-trimethylbenzoylphenylphosphinate, benzophenones, hydroxyacetophenones, phenylglyoxylic acid and its derivatives or mixtures of these photoinitiators. Examples which may be mentioned are benzophenone, acetophenone, acetonaphthoquinone, methyl ethyl ketone, valerophenone, hexanophenone, α-phenylbutyrophenone, p-morpholinopropiophenone, dibenzosuberone, 4-morpholinobenzophenone, 4-morpholinodeoxybenzoin, p-diacetylbenzene, 4-aminobenzophenone, 4'-methoxyacetophenone, β-methylanthraquinone, tert-butylanthraquinone, anthraquinone-carboxylic acid ester, benzaldehyde, α-tetralone, 9-acetylphenanthrene, 2-acetylphenanthrene, 10-thioxanthenone, 3-acetylphenanthrene, 3-acetylindole, 9-fluorenone, 1-indanone, 1,3,4- triacetylbenzene, thioxanthen-9-one, xanthene-9-one, 2,4-dimethylthioxanthone, 2,4-diethylthioxanthone, 2,4-di- iso -propylthioxanthon, 2,4-dichlorothioxanthone, benzoin, benzoin iso-butyl ether, Chloroxanthenone, benzoin tetrahydropyranyl ether, benzoin methyl ether, benzoin ethyl ether, benzoin butyl ether, benzoin iso- propyl ether, 7-H-benzoin methyl ether, benz [de] anthracen-7-one, 1-naphthaldehyde, 4,4'-bis (dimethylamino) benzophenone, 4-phenylbenzophenone, 4-chlorobenzophenone, Michler's ketone, 1-acetonaphthone, 2-acetonaphthone, 1-benzoylcyclohexan-1-ol, 2-hydroxy-2,2-dimethylacetophenone, 2,2-dimethoxy-2- phenylacetophenone, 2,2-diethoxy-2-phenylacetophenone, 1,1-dichloroacetophenone, 1-hydroxycetophenone, acetophenone dimethyl ketal, o-methoxybenzophenone, triphenylphosphine, trio-to lylphosphine, benz [a] anthracene-7,12-dione, 2,2-diethoxyacetophenone, benzil ketals such as benzil dimethyl ketal, 2-methyl-1- [4- (methylthio) phenyl] -2-morpholinopropan-1-one, anthraquinones such as 2-methylanthraquinone, 2-ethylanthraquinone, 2- tert- butylanthraquinone, 1-chloroanthraquinone, 2-amylanthraquinone and 2,3-butanedione.

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

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

In particular, mixtures of different photoinitiators can be used.

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

As further paint typical additives (F4), 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, antifoaming agents, fragrances, surface-active agents , Viscosity modifiers, plasticizers, plasticizers, tackifiers, chelating agents or compatibilizers.

As a post-curing accelerator, e.g. Tin octoate, zinc octoate, dibutyltin laureate or diazabicyclo [3.2.2] octane.

Furthermore, one or more photochemically and / or thermally activatable initiators may be added, e.g. Potassium peroxodisulfate, dibenzoyl peroxide, cyclohexanone peroxide, di-tert-butyl peroxide, azobisisobutyronitrile, cyclohexylsulfonylacetyl peroxide, di-isopropyl percarbonate, tert-butyl peroctoate or benzpinacol, and for example those thermally activatable initiators having a half-life of more than 80 ° C 100 hours, such as di-t-butyl peroxide, cumene hydroperoxide, dicumyl peroxide, t-butyl perbenzoate, silylated pinacols, the z. B. commercially available under the trade name ADDID 600 from Wacker or hydroxyl-containing amine-N-oxides, 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 in " Polymer Handbook, 2nd ed., Wiley & Sons, New York described s.

Suitable thickeners besides free-radically (co) polymerized (co) polymers, customary organic and inorganic thickeners such as hydroxymethylcellulose or bentonite.

As chelating agents, e.g. Ethylenediaminetic acid and its salts and β-diketones can be used.

Suitable fillers include silicates, e.g. Example by hydrolysis of silicon tetrachloride available silicates such as Aerosl ^® the Fa. 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 ^® grades from Ciba-Spezialitatenchemie) and benzophenones. These may 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 derivatives thereof, eg. B. bis (2,2,6,6-tetra-methyl-4-piperidyl) sebacinate used. Stabilizers are usually used in amounts of 0.1 to 5.0 wt .-%, based on the solid components contained in the preparation.

Further 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-tetramethyl-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 p-aminophenol, p-nitrosophenol, 2-tert-butylphenol, 4-tert-butylphenol, 2,4-di- tert Butylphenol, 2-methyl-4- tert -butylphenol, 4-methyl-2,6-tert-butylphenol (2,6- tert -butyl-p-cresol) or 4- tert -butyl-2 , 6-dimethylphenol, quinones, such as hydroquinone or hydroquinone monomethyl ether, aromatic amines, such as N, N-diphenylamine, N-nitroso-diphenylamine, phenylenediamines, such as N, N'-dialkyl-para-phenylenediamine, wherein the alkyl radicals are the same or may be different and each independently of one another from 1 to 4 carbon atoms and may be straight or branched, hydroxylamines such as N, N-diethylhydroxylamine, urea derivatives such as urea or thiourea, phosphorus-containing compounds such as triphenylphosphine, triphenyl phosphite or triethyl phosphite or sulfur-containing Ver bonds, such as diphenyl sulfide or phenothiazine.

Typical compositions for radiation-curable compositions are, for example

• (F1) 0 - 100 Gew%, bevorzugt 50 - 90, besonders bevorzugt 60 - 90 und insbesondere 60 - 80 Gew%,
• (F2)0 - 60 Gew%, bevorzugt 5 - 50, besonders bevorzugt 6 - 40 und insbesondere 10 - 30 Gew%,
• (F3)0 - 20 Gew%, bevorzugt 0,5 - 15, besonders bevorzugt 1 - 10 und insbesondere 2 - 5 Gew% sowie
• (F4) 0 - 50 Gew%, bevorzugt 2 - 40, besonders bevorzugt 3 - 30 und insbesondere 5 - 20 Gew%,

mit der Maßgabe, daß (F1), (F2), (F3) und (F4) zusammen 100 Gew% ergeben.

• (F1) 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 in particular 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 also
• (F4) 0-50% by weight, preferably 2-40, particularly preferably 3-30 and in particular 5-20% by weight,

with the proviso that (F1), (F2), (F3) and (F4) together give 100% by weight.

In particularly preferred radiation-curable compositions, compound (F1) consists of from 10 to 100% by weight, based on the total amount of compound (F1), of urethane (meth) acrylate (s), epoxyacrylates, polyether acrylates or polyester acrylates.

Particularly suitable radiation-curable compositions which can be used as layers (F) are those in EP-A1 942 022 , there especially from S. 4, Z. 18 to P. 18, Z.31 described in DE-A1 199 44 156 , P. 1, lines 26 to 6, line 63 and in DE-A1 199 56 231 , P. 2, Z. 33 to p. 4, Z. 65, as well as those in the German patent application with the file reference 101 40 769.6 and the submission date 20.08.2001.

The substrates are coated by customary methods 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, if appropriate with heating, being removed. If desired, this process can be repeated one or more times. The application to the substrate can in a known manner, for. Example by spraying, filling, doctoring, brushing, rolling, rolling, pouring, lamination, injection molding or coextrusion. The coating thickness is generally in a range of 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 oxygen-containing atmosphere or preferably under inert gas, optionally at temperatures up to the height of the drying temperature and then at temperatures up to at 160 ° C, preferably between 60 and 160 ° C, thermally treated.

The process for coating substrates can also be carried out so that after application of the coating composition initially at temperatures up to 160 ° C, preferably between 60 and 160 ° C, thermally treated and then with electron beams or UV exposure under oxygen or preferably under inert gas is hardened.

If desired, the curing of the films formed on the substrate can be effected exclusively 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 NIR radiation, wherein NIR radiation here electromagnetic radiation in the wavelength range of 760 nm to 2.5 microns, preferably from 900 to 1500 nm is designated.

Optionally, if several layers of the coating composition are applied to one another, thermal, NIR and / or radiation curing can take place after each coating operation.

Suitable radiation sources for radiation curing are, for example, low-pressure mercury lamps, medium-pressure lamps with high-pressure lamps and fluorescent tubes, pulse emitters, metal halide, electronic flash devices, whereby a Radiation curing without photoinitiator is possible, or Excimerstrahler. The radiation is cured by exposure to high-energy radiation, ie UV radiation or daylight, preferably light in the wavelength range of λ = 200 to 700 nm, particularly preferably from λ = 200 to 500 nm and most preferably λ = 250 to 400 nm, or by Irradiation with high-energy electrons (electron radiation, 150 to 300 keV). The radiation sources used are, for example, high-pressure mercury vapor lamps, lasers, pulsed lamps (flash light), halogen lamps or excimer radiators. The radiation dose for UV curing, which is usually sufficient for crosslinking, is in the range from 80 to 3000 mJ / cm ² .

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

These can also radiate in different wavelength ranges.

The irradiation may optionally also in the absence of oxygen, for. B. under inert gas atmosphere, are performed.
As inert gases are preferably nitrogen, noble gases, carbon dioxide, or combustion gases. Furthermore, the irradiation can be carried out by covering the coating composition with transparent media. Transparent.Media are z. As plastic films, glass or liquids, eg. B. water. Particular preference is given to irradiation in the manner as described in US Pat DE-A1 199 57 900 is described.

1. i) ein Substrat mit einer Beschichtungsmasse, wie zuvor beschrieben, beschichtet,
2. ii) flüchtige Bestandteile der Beschichtungsmasse zur Filmbildung unter Bedingungen entfernt, bei denen der Photoinitiator (C) im wesentlichen noch keine freien Radikale ausbildet,
3. iii) gegebenenfalls den in Schritt ii) gebildeten Film mit energiereicher Strahlung bestrahlt, wobei der Film vorgehärtet wird, und anschließend gegebenenfalls den mit dem vorgehärteten Film beschichteten Gegenstand mechanisch bearbeitet oder die Oberfläche des vorgehärteten Films mit einem anderen Substrat in Kontakt bringt,
4. iv) dem Film thermisch oder mit NIR-Strahlung endhärtet Dabei können die Schritte iv) und iii) auch in umgekehrter Reihenfolge durchgeführt, d. h. der Film kann zuerst thermisch oder per NIR-Strahlung und dann mit energiereicher Strahlung gehärtet werden.

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

1. i) coating a substrate with a coating composition as described above,
2. ii) removing volatile constituents of the coating composition for film formation under conditions in which the photoinitiator (C) still substantially does not form free radicals,
3. iii) optionally irradiating the film formed in step ii) with high energy radiation, whereby the film is precured, then optionally mechanically working the precured film coated article or contacting the surface of the precured film with another substrate,
4. iv) the film is cured thermally or with NIR radiation. In this case, steps iv) and iii) can also be carried out in the reverse order, ie the film can first be cured thermally or by NIR radiation and then with high-energy radiation.

Furthermore, also substrate coated with a multi-layer coating according to the invention are the subject of the present invention.

Likewise provided by the present invention is a process for coating substrates with at least one radiation-curable coating system (F), in which between the substrate and the at least one radiation-curable coating system (F) an elastic intermediate layer (D) with a glass transition temperature (Tg) of -20 ° C or lower is applied.

The coating can take place according to one of the above-mentioned methods, and the above applies to the radiation-curable coating systems (F) and the elastic intermediate layer (D).

The thickness of such a layer to be cured as described may be from 0.1 μm to several mm, preferably from 1 to 2000 μm, more preferably from 5 to 1000 μm, most preferably from 10 to 500 μm and especially from 10 to 250 μm.

For a given system, the fracture mechanical behavior is determined by the ratio V of the interlayer thickness ZS (layer (D)) to the total thickness of the interlayer plus the thickness DL of the topcoat, i. the sum of the thickness of the layers (E) and (F), determined 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, values V are at least 0.05 at temperatures of at least 25 ° C., preferably at least 0.1 at temperatures of at least 0 ° C., more 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.

The multicoat paint systems according to the invention achieve improved adhesion in comparison with known UV-curable coatings, especially on engineering plastics as well as better hardness, elasticity, abrasion resistance and chemical resistance.

The multicoat paint systems according to the invention are particularly preferably suitable as or in exterior coatings, ie those applications that are exposed to daylight, preferably 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 clearcoats and topcoats, both for the automotive exterior and for the interior.

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

With the multicoat paint systems according to the invention, high scratch resistance can be achieved.

Ppm and percentages used in this specification, unless otherwise indicated, are by weight percent and ppm.

Examples

The scratch resistance was determined by the Scotch Brite test, as determined in the DE-A1 199 40 312 , P. 8, Z. 64 to p. 9, Z. 5:

The test piece is a 3 x 3 cm large, silicon carbide-modified nonwoven fabric (Scotch Brite SUFN, 3M Germany, 41453 Neuss) attached to a cylinder. This cylinder presses the nonwoven fabric at 750 g onto the coating and is pneumatically moved across the coating. The distance of the deflection is 7 cm. After 10 or 50 double strokes (DH), the gloss (six-fold determination) is measured analogously to DIN 67530, ISO 2813 at an incidence angle of 60 ° in the middle region of the stress. 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 strength a _cu was measured according to DIN EN ISO 179 / 1fU at -50 ° C.

The topcoat 1 was prepared from Laromer® LR 8987 from BASF AG, Ludwigshafen and additives.

The topcoat 2 was prepared from Laromer® LR 8949 from BASF AG, Ludwigshafen and additives.

The following substrates were used: substratum primer topcoat V a _{cu at -50 ° C} [kJ / m ² ] f [Hz] Loss loss after 10/50 DH [%] ASA / PC (Luran SC) Kraton D1101 1 0.34 100 1000 18/31 ASA / PC (Luran SC) Kraton KX222 2 0.21 15 1000 9.25 ASA / PC (Luran SC) Vector 8508 2 0.30 90 1000 12.28 ABS / PA (Terblend N) Kraton D1101 1 0.2 50 1000 13/21 ABS / PA (Terblend N) Kraton D4150 2 0.13 40 1000 8.22 ABS / PA (Terblend N) Vector 8508 2 0.3 40 1000 11/23 SAN (Luran) Vector D1101 1 0.1 13 500 9.18 PMMA (Lucryl) - - - <2 500 43/63

Claims (10)

1. 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 (measured in the frequency range up to 1000 Hz).
2. The multicoat system according to claim 1, composed of

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

   (E) if appropriate, at least one coat which is pigmented and/or provided with effect substances,

   (D) at least one elastic intercoat (D) having a glass transition temperature (Tg) of -20°C or less,

   (C) if appropriate, at least one coat selected from the group consisting of primer, basecoat, undercoat, coat pigmented or provided with effect substances, and substrate 2,

   (B) if appropriate, at least one elastic intercoat, if coat (C) is a substrate 2, and

   (A) substrate 1.
3. The multicoat system according to claim 1 or 2, wherein the substrates 1 and/or 2 in the coats (A) and/or (C) are selected from the group consisting of paper, plastics, and metals.
4. The multicoat system according to claim 1 or 2, wherein the substrates are selected from the group consisting of PP (polypropylene), SAN (styreneacrylonitrile copolymers), PC, PMMA, PBT, PA, ASA (acrylonitrile-styrene-acrylate copolymers) and ABS (acrylonitrile-butadiene-styrene-copolymers) and also their physical mixtures (blends).
5. The multicoat system according to any of the above claims, wherein the thickness of the elastic intercoat (D) is from 0.5 to 500 µm.
6. The multicoat system according to any of the above claims, wherein at least one compound in the elastic intercoat (D) is selected from the group consisting of thermoplastic elastomers, polyacrylates, and poly-iso-butenes.
7. The multicoat system according to claim 6, wherein at least one compound in the elastic intercoat (D) is selected from the group consisting of styrenebutadiene-styrene (SBS), styrene-isoprene-styrene (SIS), styrene-ethylene/butylene-styrene (SEBS) and styrene-ethylene/propylene-styrene (SEPS) block polymers.
8. A substrate coated with a multicoat system according to any of the above claims.
9. A method of coating a substrate with at least one radiation-curable coating system (F), which comprises applying, between the substrate and said at least one radiation-curable coating system (F), an elastic intercoat (D) having a glass transition temperature (Tg) of -20°C or less.
10. The use of a multicoat system according to any of claims 1 to 7 for the coating of buildings or parts of buildings, interior coatings or coatings on vehicles and aircraft.