Highly scratch-resistant multi-layer paint coating, method for producing the same and the use thereof

The present invention relates to a new highly scratch-resistant multicoat clearcoat system on the basis of at least two coating materials curable with actinic radiation. The present invention also relates to the use of new highly scratch-resistant multilayer clearcoat in automotive OEM finishing and refinishing, the industrial coating, including coil coating and container coating, the Plastics, and furniture coating. Furthermore, the present Invention provides a novel process for producing multicoat clearcoats.

Car bodies, plastic parts for automobiles or household appliances and industrial Components are nowadays protected by a clearcoat. Here, the Clearcoat be used as the sole coating layer or the uppermost layer of a form multilayer topcoat.

In particular, automobile bodies are mostly with a multilayer Top coat system provided. As the final coat clearcoats are often applied. Two components - through standard and known one-component (1K) come (2K) -, multicomponent (3K, 4K) -Pulver- or powder slurry clearcoats or UV-curable Clearcoat materials.

Component (1K) -, two-component (2K) - or multicomponent (3K, 4K) clearcoat materials for example in the patents US-A-5,474,811, US Patent 5,356,669, US-A- 5,605,965, WO 94/10211, WO 94/10212, WO 94/10213, EP-A-0594068, EP-A-0594071, EP-A-0594142, EP-A-0604992, WO 94/22969, EP-A-0596460 or WO 92/22615 described.

Powder clearcoats are known from the German patent DE-A-42 22 194 or the product information bulletin from BASF Lacke + Farben AG, "Powder Coatings" 1990 known.

A powder coating, which is thermally and with actinic radiation curable, is known from European Patent EP-A-0844286 is known. It contains an unsaturated Binder and a second resin copolymerizable therewith and a photoinitiator and a thermal initiator and is thus thermally and with actinic radiation, curable. However, this dual-cure powder coating is used as a pigmented topcoat, thermally which on the surface with UV light and in the areas close to the substrate is cured. Whether this known powder lacquer for the production of Clearcoats, especially in multicoat systems is compatible, can be of not refer to Patent.

Powder slurry coating materials is powder coating in the form of aqueous dispersions. Such slurries are disclosed in US Patent US-A-4,268,542 and German patent applications DE-A-195 18 392.4 not and DE-A-196 13 547 and the described German patent application DE-A-198 14 471.7.

UV-curable clearcoat materials are, for example, from the patents EP-A-0540884, EP A-0,568,967 or US-A-4,675,234 forth.

Each of these clearcoat materials has specific strengths and weaknesses. Thus, for using these clearcoats multicoat systems which satisfy the optical requirements. however the scratch-resistant component (1K) clearcoat sometimes not enough weather-resistant, whereas the weathering resistant two-component (2K) - or Multicomponent (3K, 4K) clearcoats are often not sufficiently scratch-resistant. Some Component (1K) clearcoats are indeed scratch resistant and weather resistant, but have in Combined with frequently employed waterborne basecoats surface defects such as Shrinkage (wrinkling) on.

Powder clearcoats, powder slurry clearcoats and UV curable clearcoat materials in contrast, have a not entirely satisfactory on interlayer adhesion, without the problems of Scratch resistance or etch resistance would be completely dissolved.

From EP-A-0568967 discloses a process for the production of multi-layer coatings is known in which a thermally curable clearcoat film by the wet-on-wet technique is applied to a pigmented basecoat film, after which the two layers in the Heat cured together. is on the cured clearcoat film then at least one further clearcoat based on actinic Radiation applied coating materials curable with actinic radiation, or cured with actinic radiation and thermally. This method provides Clearcoat coatings of high chemical resistance and optical quality. However, the Scratch resistance is not satisfactory.

Furthermore, from EP-A-0568967 is shown a method in which an actinic Radiation curable coating material applied to the pigmented basecoat film and is cured. Subsequently, a further layer of the same coating material applied and cured with actinic radiation. While it results in a high-gloss Surface without perceptible structure, however yellowed the clear lacquer coating in question. Also, the scratch resistance can still be desired.

More recently, so-called sol-gel clearcoat materials based on siloxane coating developed formulations by hydrolysis and condensation of silane compounds are obtained. These paints, of the coating compositions on plastics be used, for example, in the German patents DE-A-43 03 570, 34 07 087 40 11 045 40 25 215 38 28 098 40 20 316 or 41 22 743..

Sol-gel clearcoats impart plastic substrates such. As spectacle lenses or motorcycle helmet visors, very good scratch resistance. This scratch resistance is known by the OEM (original equipment manufacturing) clearcoat materials commonly used in the Finishing of vehicles are used not reached. On the part of Automotive industry is now made the request, this improved scratch resistance on clear coat layers used in the finishing of automobiles transfer. Here are mainly the high-wear parts of Automobile bodies such as the bonnet, bumpers, sills or doors in the field of Door handles are better protected.

Replacement of OEM clearcoats commonly used in automotive finishing or OEM powder slurry clearcoats by sol-gel clearcoat materials is, however, not readily possible, because they are too brittle for this z. B. or because in trying to them the OEM adapt requirements frequently provides only poor optical properties (appearance) be achieved. Furthermore it can not be administered <8 to 10 microns in thickness. In addition, components can the sol-gel clearcoat materials in their drying and / or curing chip off, ie, they are absorbed by the substrate, whereby the hardness of the relevant Clearcoat systems is lost. Above all, the sol-gel clearcoat materials are too expensive.

The economically more favorable use of the sol-gel clearcoat materials as an additional coat over the clearcoats used to date gives adhesion problems within the multilayer clearcoat between the clearcoat and the sol-gel layer in particular occur by falling rocks and on exposure to condensation. This Problem is sometimes exacerbated by the fact that the adhesion between the Clearcoat film and the substrate is affected.

These problems can be solved to a certain degree, that the Clearcoat film which is to be coated with the sol-gel clearcoat material, only partially hardens, so that the sol-gel coating in the joint curing to a certain extent can be chemically anchored to the clearcoat film. However, the second requires Clearcoat for its curing a long oven drying time, what a significant Disadvantage.

Object of the present invention is to provide a new multi-layer clearcoat provide, which no longer has the disadvantages of the prior art, but easily producible, highly scratch-resistant, weather-resistant, non-yellowing, hard, flexible and free from surface defects is, on all substrates and within the Clearcoat has a high adhesion and excellent in a can be produced overall visual necessary high film thickness. in addition it is the object of the present invention provides a novel method of producing such mono- or multi-layer clear coat layers of at least two actinic radiation provide curable coating materials.

Accordingly, the new highly scratch-resistant multicoat clearcoat system A has a primed or unprimed substrate found, which is preparable by reacting

<ul><li>1. at least one clearcoat film I of a with actinic radiation and thermally curable coating material applied to the surface T of the substrate and partially cures and </li><li>2. a further clearcoat film II of a and with actinic radiation optionally thermally curable coating material II, containing nanoparticles, applied to the surface of the clearcoat film (s) I, after which</li><li>3. the clearcoat films I and II together with actinic radiation and thermally cures.</li></ul>

Alternatively, the more new highly scratch-resistant multicoat clearcoat system was A found for a primed or unprimed substrate, which is preparable by one

<ul><li>1. at least one clearcoat film I of a with actinic radiation and thermally curable coating material I applied to the surface of the substrate, cures and roughen,</li><li>2. a further clearcoat film II of a and with actinic radiation optionally thermally curable coating material II, containing nanoparticles, applied to the outer surface of the clearcoat film (s) I, after which</li><li>3. the clearcoat film II with actinic radiation, and optionally thermally cures.</li></ul>

The two new highly scratch-resistant multicoat clearcoats A are in hereinafter referred to as the "inventive clearcoats A".

Furthermore, the novel process for producing a highly scratch-resistant was multilayer clearcoat A on a primed or unprimed substrate found, in which

<ul><li>1. at least one clearcoat film I of a with actinic radiation and thermally curable coating material I applied to the surface of the substrate and partially cures and </li><li>2. a further clearcoat film II of a and with actinic radiation optionally thermally curable coating material II, containing nanoparticles, applied to the surface of the clearcoat film (s) I, after which</li><li>3. the clearcoat films I and II together with actinic radiation and thermally cures.</li></ul>

As an alternative, the further new process for the preparation was a highly scratch-resistant multilayer clearcoat A on a primed or unprimed substrate found, in which

<ul><li>1. at least one clearcoat film I of a with actinic radiation and thermally curable coating material I applied to the surface of the substrate, cures and roughen,</li><li>2. a further clearcoat film II of a and with actinic radiation optionally thermally curable coating material II, containing nanoparticles, applied to the outer surface of the clearcoat film (s) I, after which</li><li>3. the clearcoat film II with actinic radiation, and optionally thermally cures.</li></ul>

The two new processes for producing highly scratch-resistant clearcoats A are referred to as "invention method A" hereinafter.

In addition, the new highly scratch-resistant color and / or effect was Found Multilayer coating B for a primed or unprimed substrate, which is preparable by reacting

<ul><li>1. at least one color and / or effect basecoat film III of a thermally and, where appropriate, with actinic radiation curable pigmented Coating material III applied to the surface of the substrate and without cure, dry, </li><li>2. at least one clearcoat film I of a with actinic radiation and thermally curable coating material I on the surface of the basecoat film III wet-in- applied wet and partially cures and</li><li>3. a further clearcoat film II and from an actinic radiation optionally thermally curable coating material II, containing nanoparticles, applied to the surface of the clearcoat film (s) I, after which</li><li>4. the basecoat film (s) III and the clearcoat films I and II together with actinic radiation and thermally cured.</li></ul>

Alternatively, the further the new highly scratch-resistant color and / or was effect paint system B for a primed or unprimed substrate found which is preparable by reacting

<ul><li>1. at least one color and / or effect basecoat film III of a thermally and, where appropriate, with actinic radiation curable pigmented Coating material III applied to the surface of the substrate and without cure, dry,</li><li>2. at least one clearcoat film I of a with actinic radiation and thermally curable coating material I on the surface of the basecoat film III wet-in- wet applied,</li><li>3. the basecoat film III, and clearcoat film (s) together, thermally I and with actinic radiation cures,</li><li>4. The outer surface of the clearcoat film (s) I roughen,</li><li>5. a further clearcoat film II of a and with actinic radiation optionally thermally curable coating material II, containing nanoparticles, applied to the outer surface of the clearcoat film (s) I, after which </li><li>6. the clearcoat film II with actinic radiation, and optionally thermally cures.</li></ul>

Now, the new color and / or effect paint systems are B referred to as "inventive multilayer coatings B".

Moreover, the new method for producing a highly scratch-resistant color-was and / or effect paint system on a primed or unprimed B Found substrate, in which

<ul><li>1. at least one color and / or effect basecoat film III of a thermally and, where appropriate, with actinic radiation curable pigmented Coating material III applied to the surface of the substrate and without cure, dry,</li><li>2. at least one clearcoat film I of a with actinic radiation and thermally curable coating material I on the surface of the basecoat film III wet-in- applied wet and partially cures and</li><li>3. a further clearcoat film II and from an actinic radiation optionally thermally curable coating material II, containing nanoparticles, applied to the surface of the clearcoat film (s) I, after which</li><li>4. the basecoat film (s) III and the clearcoat films I and II together with actinic radiation and thermally cured.</li></ul>

As an alternative, the further new process for the preparation was a highly scratch-resistant color and / or effect paint system on a B primed or unprimed substrate found, in which

<ul><li>1. at least one color and / or effect basecoat film III of a thermally and, where appropriate, with actinic radiation curable pigmented Coating material III applied to the surface of the substrate and without cure, dry, </li><li>2. at least one clearcoat film I of a with actinic radiation and thermally curable coating material I on the surface of the basecoat film III wet-in- wet applied,</li><li>3. the basecoat film III, and clearcoat film (s) together, thermally I and with actinic radiation cures,</li><li>4. The outer surface of the clearcoat film (s) I roughen,</li><li>5. a further clearcoat film II of a and with actinic radiation optionally thermally curable coating material II, containing nanoparticles, applied to the outer surface of the clearcoat film (s) I, after which</li><li>6. the clearcoat film II with actinic radiation, and optionally thermally cures.</li></ul>

The following are the two new methods as "inventive method B" designated.

In the present invention, the term "thermal curing" means the by heat initiated curing of a lacquer layer of a coating material, wherein normally a separate crosslinking agent is employed. Usually this is referred to by the art as external crosslinking. Where the crosslinking agents in already installed the binders, the term self-crosslinking. According to , external crosslinking is of advantage and is therefore employed with preference.

In the present invention, actinic radiation means electron beams or, preferably, UV radiation. Curing by ultraviolet radiation is typically initiated by free-radical or cationic photoinitiators and their A mechanism according to a radical or cationic photopolymerization.

Where thermal curing and curing with actinic light for a coating material applied together, also referred to as "dual cure".

In view of the state of the art it was surprising and for the person skilled not foreseeable that the very complex task which the invention is based with Help the clearcoat A inventive and inventive Multilayer coating B and the inventive method for their preparation could be solved. It is particularly surprising that not only the inter-layer adhesion within the inventive clearcoat A, but also the adhesion to the Basecoat film III within the inventive multicoat B beyond the known range are also improved. Here, the invention Clearcoat A and the multilayer coating of the invention B excellent optical properties, particularly a high abundance, high DOI values, a high Gloss and no yellowing. Due to the dual-cure curing even complex Components and fittings in their shadow areas in a simple manner fully be cured. In all of the inventive clearcoat A and the Multilayer coating according to the invention B, providing excellent resistance to weathering and Chemical stability. Last but not least they are extremely scratch resistant and resist even the treatment with steel wool. Above all, they are not by the usually damaged in car washes applied devices.

The clearcoat A invention is outstandingly suitable for the coating of primed or unprimed substrate.

Suitable substrates are all surfaces that a combined curing come are accessible using heat and actinic radiation into consideration, which are z. B. metals, plastics, wood, ceramic, stone, textile, fiber composites, leather, glass, Fibers, glass wool, rock wool, mineral- and resin-bound building materials, such as plasterboard and Cement slabs or roof tiles. Accordingly, the inventive clearcoat A is also suitable for applications outside of automotive finishing, especially for Lackie tion of furniture and for industrial coating, including coil coating and container Coating. In context of industrial coatings it is suitable for painting virtually all parts for private or industrial use such as radiators, Household appliances, small metal parts, hubcaps or wheel rims. In particular, the inventive clearcoat A useful as a coating over basecoats, preferably in the automotive industry. It is particularly suitable as a clearcoat over Waterborne basecoats based on polyesters, polyurethane resins and amino resins, particularly in the context of the inventive multicoat B.

The clearcoat A or the invention invention Multilayer coating B may especially primed or unprimed Art materials such. B. ABS, AMMA, ASA, CA, CAB, EP, UF, CF, MF, MPF, PF, PAN, PA, PE, HDPE, LDPE, LLDPE, UHMWPE, PET, PMMA, PP, PS, SB, PUR, PVC, RF, SAN, PBT, PPE, POM, PUR-RIM, SMC, BMC, PP-EPDM and UP (abbreviations according to DIN 7728P1). The plastics to be coated may of course also be polymer blends, modified plastics or fiber-reinforced plastics. It can also for coating commonly used in vehicle, especially motor vehicle used plastics are used.

Nonfunctionalized and / or nonpolar substrate surfaces may be prior to coating in a known manner to a pretreatment, such as with a plasma or , Be subjected by flaming.

The clearcoat A invention can be produced by the first in a Step at least one clearcoat film I of a and with actinic radiation thermally curable coating material I applied to the surface of the substrate.

Thus, in the context of the present invention, only one clearcoat film I of Coating material I are applied. However, two or more such Clearcoat films I are applied. Here, each different Coating materials I applied for the construction of the clearcoat films I. In the almost all cases, however, the desired property profile of the invention A clearcoat scored with a clearcoat film I.

The clearcoat film I is applied in a wet film thickness such that curing in the finished inventive clearcoat A dry film thickness of 10 to 100, preferably 15 to 75, particularly preferably 20 to 55 and especially 20 to 35 microns results.

The application of the coating material I for the purpose of preparation of the clear coat layer I can by any customary application method, such. As spraying, knife coating, brushing, Pouring, dipping or rolling. Preferably spray application methods employed, such as compressed air spraying, airless spraying, high-speed rotation, electrostatic spray application (ESTA), alone or in conjunction with hot spray application such as hot air - hot spraying. The applications can operate in temperatures from Max. 70 to 80 ° C are carried out, so that appropriate application viscosities be achieved without a during the short period of thermal stress Change or damage to the coating material I and its optionally reprocessing overspray entering. For instance, hot spraying may be configured, that the coating material I is heated only very briefly in the spray nozzle or shortly before.

The spray booth used for application may, for example, with a optionally temperature-operated, the appropriate with a Absorption medium for the overspray, an example. As the coating material I itself operated, becomes.

Application is preferably under illumination with visible light having a wavelength carried out by more than 550 nm or with exclusion of light. This will be a material Alteration or damage to the coating material I and the overspray is avoided.

Naturally, the application methods described above and in the Preparation of the clearcoat film II or the basecoat film III, and optionally applied further coating films under the procedures A or B according to the invention will.

According to the clearcoat film I is partially cured after application. In terms of method, the partial curing not of a different usually carried out complete curing of a lacquer layer. It is hereby only networked so long that the clearcoat film I one hand for the purpose of A method according to the invention or B sufficient dimensional stability and on the other hand plenty of cross-linkable functional groups described below (a11) and (a21) and / or (a12) and (a22) (complementary functional groups) for the Postcrosslinking and has for the interlayer adhesion. The extent of the partial Curing can therefore vary widely and is guided by the requirements of each case. It may, however, by a person of general Expertise and / or be determined by simple preliminary tests. Preferably be 0.5 to 99.5, particularly preferably 1 to 99, very particularly preferably 2 to 90 and in particular 3 to 80 mol% of that present in the coating material I cross-linkable functional groups reacted. Very particular preference is, if the clearcoat film I following its partial curing is still tacky.

According to the invention clearcoat film I with actinic radiation or thermally or with actinic radiation and thermally partially cured. According to the invention it is of Advantageously, the clearcoat film I partially cure with actinic radiation, because in this case the Degree of crosslinking are particularly well controlled by the entry of radiant energy can.

Curing may take place after a period of inactivity. They may have a duration of 30 s to 2 hours, preferably 1 minute to 1 hour and more preferably 1 min to 30 min have. The rest period For example, use the leveling and devolatilization of the clearcoat film I or The evaporation of volatile constituents such as solvents, water or carbon dioxide, if The coating material was applied using supercritical carbon dioxide as solvent is. The rest period may by the use of elevated temperatures up to 80 ° Celsius are supported and / or provided this does not damage or Changes in the clearcoat film I enter, such as premature complete Networking.

According to the invention the curing with actinic radiation is effected using UV radiation or Electron. It may optionally with actinic radiation from other Radiation sources performed or supplemented. In the case of electron beams preferably carried out under an inert atmosphere. This can, for example, by supplying of carbon dioxide and / or nitrogen directly to the surface of the clearcoat film I be guaranteed.

Also in the case of curing with UV radiation, in order to avoid the formation of ozone, operate under inert gas.

For curing with actinic radiation are the customary and known Radiation sources and optical auxiliary applied. Examples of suitable Radiation sources are pressure or low, which optionally doped with lead in order to open up a radiation window up to 405 nm, or Electron beam sources. Their arrangement is known in principle and may the Circumstances of the workpiece and the process parameters to be adjusted. at workpieces of complex shape such as automobile bodies can not direct Radiation accessible (shadow regions) such as cavities, folds and other structural undercuts using point, small or round emitters conjunction with an automatic movement means for the irradiation of Cavities or edges (partially) cured.

The equipment and conditions for these curing methods are, for example, in R. Holmes, UV and EB Curing Formulations for Printing Inks, Coatings and Paints, SITA Technology, Academic Press, London, United Kingdom, 1984..

Here, the (partial) curing are carried out in stages, ie, by multiple Exposure or irradiation with actinic radiation. This can also alternately take place, ie, by curing alternately with UV radiation and electron beams.

The thermal curing has no special features but instead takes place by the customary and known methods such as heating in a convection oven or Irradiation with IR lamps. As with the curing with actinic radiation may also be the thermal curing take place in stages. Advantageously, the thermal curing at a temperature of 50 to 100 ° C, particularly preferably 80 to 100 ° C and in particular 90 to 100 ° C for a period of 1 min to 2 h, more preferably 2 min up to 1 hour, and in particular from 3 min to 30 min. Where substrates are used which are subjected to high thermal loads, thermal crosslinking may also be carried out at temperatures be carried out above 100 ° C. Generally, it is recommended that this Temperatures of 180 ° C, preferably 160 ° C and in particular 140 ° C to not exceed.

Where thermal curing and curing with actinic radiation together applied these methods can be used simultaneously or alternately.

Where the two curing methods are used alternately, may, for example with the begun thermal curing and end with actinic radiation curing will. In other cases it may prove to be advantageous, with curing with actinic radiation to begin and to end. The expert can the Curing method for the particular case in the most advantageous due his general knowledge optionally with the aid of simple preliminary determine.

Of course, the curing methods described above and in the Preparation of the clearcoat film II or the basecoat film III, and optionally applied further coating films under the procedures A or B according to the invention will.

The present invention for producing the clearcoat film I want to use Coating material I contains at least one constituent (a1) having at least two functional groups (a11), which serve for crosslinking with actinic radiation.

Examples of suitable functional groups (a11) are epoxy groups or olefinically unsaturated double bonds, or as in vinyl, allyl, cinnamoyl, methacrylic Acrylic groups, especially methacrylic or acrylic groups, are present. As is known, the epoxide groups for cationic photopolymerization are used, whereas the olefinically unsaturated double bonds in the main for the radical Photopolymerization come into consideration. According to the invention the component (a1) contain epoxide groups and olefinic double bonds, so that after two Mechanisms of crosslinking can also be subjected to actinic radiation. It is of advantage, however exclusively olefinically unsaturated double bonds of the type mentioned to use as functional groups (a11).

Further, the component according to the invention to be used (a1) at least one, preferably at least two functional groups (a12), which complementary with the functional groups (a22) of the constituent (a2) described below, thermal able to enter into crosslinking reactions included.

Examples of suitable complementary functional groups (a12) and (a22) arising from the following description, wherein R represents organic groups.

Overview: Examples of complementary functional Groups (a12) and (a22) in

The selection of the respective complementary groups (a12) and (a22) is intended to one after that they initiated no undesirable by actinic radiation reactions received or not disrupt or inhibit curing with actinic radiation, and other then, in which temperature range the thermal curing is to take place. Here, it is, especially with regard to heat-sensitive substrates such as plastics, According to the invention advantageous to choose a temperature range which 100 ° C, particular does not exceed 80 ° C. have In view of these conditions to hydroxyl groups and isocyanate groups as complementary functional groups as proved advantageous, and so are used according to the invention preferably. Particular advantages result if the hydroxyl groups as functional groups (a12) and the isocyanate groups are used as functional groups (a22).

If in the constituent (a1) any functional group (a12) is present, is in the Coating material I necessarily at least one thermally curable constituent (a7) of hereinafter described in detail, included.

Accordingly, it is in the particularly advantageous constituent (a1) with a actinic radiation or thermally curable oligomeric or polymeric compound, which optionally at least one, preferably at least two and in particular at least three Hydroxyl group (s) (a12) and at least two and in particular three (meth) acrylic groups (A11) contains.

In the present invention, an oligomeric compound is a understood compound which generally means the 2 to 15 repeating having basic structures or monomer. is A polymeric compound, on the other hand means a compound which generally average at least 10, having repeating basic structures or monomer units. Compounds of this type designated by the art as binders or resins.

In contrast, in the present invention under a low molecular weight compound, meant a compound which in itself substantially derived only from one basic structure or one monomer. Compounds of this type are referred to in the art generally as a reactive diluent.

The polymers or oligomers used as binders (a1) normally have a number average molecular weight of 500 to 50,000, preferably from 1,000 to 5,000, in. Preferably, they have a double bond equivalent weight of 400 to 2000, particularly preferably from 500 to 900.. Furthermore, they have at 23 ° C preferably has a viscosity 250-11000 mPa.s. They are preferably in an amount of 5 to 90 weight %, Particularly preferably 10 to 80 wt .-% and in particular 15 to 70 wt .-%, in each percentage being based on the total amount of the coating material I.

Examples of suitable binders or resins (a1) come from the oligomer and / or Polymer classes of the (meth) acrylic-functional (meth) acrylic copolymers, polyether acrylates, Polyester acrylates, polyesters, epoxy acrylates, urethane acrylates, amino, Melamine acrylates, silicone acrylates and phosphazene and the corresponding Methacrylates. Binders (a1) are preferably used which are free from aromatic Structural units. therefore urethane (meth) acrylates are preferred, Phosphazene (meth) acrylates and / or polyester (meth) acrylates, particularly preferably Urethane (meth) acrylates, especially aliphatic urethane (meth) acrylates, are used.

The urethane (meth) acrylates (a1) can be obtained by reacting a di- or Polyisocyanate with a chain extender from the group of the diols / polyols and / or diamines / polyamines and / or dithiols / polythiols and / or alkanolamines and then reacting the remaining free isocyanate groups with at least one Hydroxyalkyl (meth) acrylate, or hydroxyalkyl esters of other ethylenically unsaturated Carboxylic acids.

The amounts of chain extenders, di- or polyisocyanate and hydroxyalkyl are preferably chosen so that

<ul><li>1, the equivalent ratio of the NCO groups to the reactive groups of the Chain extender (hydroxyl, amino or mercaptyl) between 3: 1 and 1: 2, preferably 2: 1, and is</li><li>2. the OH groups of the hydroxyalkyl esters of ethylenically unsaturated carboxylic acids in stoichiometric amount in relation to the remaining free isocyanate groups of the Prepolymer formed from isocyanate and chain extender present.</li></ul>

It is also possible to prepare the urethane (meth) acrylates (a1) to produce, by first Of the isocyanate groups of a diisocyanate or polyisocyanate with at least one Hydroxyalkyl ester and then with the remaining isocyanate a chain extender are reacted. Also in this case, the Amounts of chain extender, isocyanate and hydroxyalkyl chosen so that the Equivalent ratio of the NCO groups to the reactive groups of Chain extender is between 3: 1 and 1: 2, preferably 2: 1, and the Equivalent ratio of the remaining NCO groups to the OH groups of the Hy droxyalkylesters 1: 1. Of course, all intermediate forms of these two methods possible. For example, a portion of the isocyanate groups of a Diisocyanate are first reacted with a diol, then a further Portion of the isocyanate with the hydroxyalkyl ester, and, subsequently, the remaining isocyanate groups are reacted with a diamine.

These various preparation of the urethane (meth) acrylates (a1) are known (see. z. B. EP-A-204 161).

A flexible urethane (meth) acrylates (a1) is for example possible by corresponding isocyanate-functional prepolymers or oligomers with relatively long, aliphatic diols and / or diamines, in particular aliphatic diols and / or Diamines having at least 6 carbon atoms. This flexibilization reaction can occur before or after the addition of acrylic or methacrylic acid onto the oligomers or prepolymers are performed.

Examples of suitable urethane (meth) acrylates (a1) are the following, commercially available polyfunctional aliphatic urethane acrylates include:

<ul><li>- Crodamer® UVU 300 from Croda Resins Ltd., Kent, United Kingdom;</li><li>- Genomer® 4302, 4235, 4297 or 4316 from Rahn Chemie, Switzerland;</li><li>- Ebecryl 284, 294, IRR351, 5129 or 1290 from UCB, Drogenbos, Belgium;</li><li>- Roskydal® LS 2989 or LS 2545 or V94-504 from Bayer AG, Germany;</li><li>- Viaktin® VTE 6160 from Vianova, Austria; or</li><li>- Laromer® 8861 from BASF AG, and experimental modifications thereof.</li></ul>

An example of a suitable polyphosphazene (meth) acrylate (a1) is the Phosphazene Idemitsu, Japan.

The coating material I of the invention further includes a component (a2).

Also in this component (a2) is a resin as defined in above in connection with the description of the resins (a1) mentioned definition. Thus originate the resins (A2) from the oligomer and polymer classes described above. are advantageous Here, the (meth) acrylic-functional (meth) acrylic copolymers, which therefore According to the invention preferably used as a resin (a2).

the resins (a2) are preferably used in an amount of 5 to 90 wt .-%, particularly preferably 10 to 80 wt .-% and more preferably 1 5 to 70 wt .-%, each based on the Total amount of the coating material I applied.

The resins (a2) contain at least two, in particular at least three functional Groups (a21), which serve for crosslinking with actinic radiation. Examples suitable for inventive use functional groups (a21) are the functional groups described above (a11).

Furthermore, the resin (a2) containing at least one, preferably at least two and in particular at least three functional groups (a22), which the thermal serve networking. Examples of suitable functional groups of this kind can be the above table refer. Isocyanate groups are particularly advantageous here and therefore according to invention particularly preferred functional groups (a22) used. Particular advantages result if the resins (a2) a content of Isocyanate groups (a22) 7-20 wt .-%, particularly preferably 8 to 18 wt .-% and in particular from 9 to 17 wt .-%, each based on the resin (A2) which.

Examples of suitable resins (a2) of the type described above are, for example, in the patents US-A-5,234,970, EP-A-0549116 or EP-A-0618244.

The coating material I for inventive use may comprise at least one Photoinitiator (a3) ​​contain. If the coating material I and the clearcoat film I with UV radiation is to be crosslinked, is the use of a photoinitiator, (a3) ​​in the generally necessary. If they are used, they are in the coating material I is preferably in proportions of 0.1 to 10 wt .-%, 1 to 8 wt .-%, and especially 2 to 6 Wt .-%, each based on the total amount of the coating material I, included.

Examples of suitable photoinitiators are those of the Norrish II type, whose Mechanism of action based on an intramolecular variant of the hydrogen Abstraction reactions based as diversely in photochemical Reactions occur (whether by way of example here to Römpp Chemie Lexikon, 9th, expanded and revised edition, Georg Thieme Verlag, Stuttgart, Vol. 4, 1991, referenced) or cationic photoinitiators (for example, refer here to Römpp Lexikon Lacke und Printing inks, Georg Thieme Verlag Stuttgart, 1998, pages 444 to 446), especially benzophenone, benzoin or benzoin ethers, or phosphine. It can also, for example, commercially available under the name Irgacure® 184, Irgacure® 1800 Irgacure® 500 from Ciba Geigy, Grenocure® MBF from Rahn and Lucirin.RTM TPO BASF AG products available are used.

Besides the photoinitiators (a3), customary sensitizers such as anthracene may in effective amounts may be used.

Further, the coating material I, at least one initiator of the thermal Networking (a4) contained. These form from 80 to 120 ° C radicals, which the start cross-linking reaction. Examples of thermolabile free-radical initiators are organic peroxides, organic azo compounds or CC-cleaving initiators such as Dialkyl, peroxycarboxylic acids, peroxodicarbonates, peroxide esters, hydroperoxides, Ketone peroxides, azo dinitriles or benzpinacol silyl ether. CC-cleaving initiators particularly preferred since no gaseous their thermal cleavage Decomposition products are formed, which could lead to defects in the coating layer. If they are used, their amounts are generally from 0.1 to 10 Wt .-%, preferably 0.5 to 8 wt .-% and in particular 1 to 5 wt .-%, each based I. on the total amount of the coating material

Moreover, the coating material may I at least one actinic radiation and / or thermally curable reactive diluents (a5) included.

Examples of suitable thermally crosslinkable reactive diluents (a5) are oligomeric polyols obtainable from oligomeric intermediates acyclic by metathesis reactions of Monoolefins and cyclic monoolefins are obtained by hydroformylation and subsequent hydrogenation are available.

Examples of suitable cyclic monoolefins are cyclobutene, cyclopentene, cyclohexene, Cyclooctene, cycloheptene, norbornene or 7-oxanorbonene.

Examples of suitable acyclic monoolefins are in hydrocarbon mixtures included which are obtained in petroleum processing by cracking (C₅-Cut).

Examples of suitable, according to the invention to be used oligoinerer polyols (a5) have a hydroxyl number (OHN) of 200 to 450, a number average molecular weight Mn of 400 to 1000 and a weight average molecular weight Mw of from 600 to 1100th

Further examples of suitable thermally crosslinkable reactive diluents (a5) are hyperbranched compounds containing a tetrafunctional central group, derived from Ditrimethylolpropane, diglycerol, ditrimethylolethane, pentaerythritol, tetrakis (2- hydroxyethyl) methane, tetrakis (3-hydroxypropyl) methane or 2,2-bis-hydroxymethyl butanediol- (1.4) (homopentaerythritol). These reactive diluents may after the customary and known methods of preparing hyperbranched and dendrimeric Connections are made. Suitable synthesis methods are, for example, in the Patent WO 93/17060 WO 96/12754 or in the book by GR Newkome, C. N. Moorefield and F. Vogtle, "Dendritic Molecules, Concepts, Syntheses, Perspectives" VCH, Weinheim, New York, 1996.,.

Further examples of suitable reactive diluents (a5) are polycarbonate, Polyester polyols, poly (meth) acrylate diols or hydroxyl- Polyadducts.

Examples of suitable reactive solvent which is used as reactive diluents (a5) can be are butyl glycol, 2-methoxypropanol, n-butanol, methoxybutanol, n-propanol, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, Ethylene glycol, diethylene glycol monomethyl ether, Diethylene, diethylene glycol diethyl ether, Diethylenglykolmo nobutylether, trimethylolpropane, 2-or Hydroxypropionsäureethylester 3-methyl-3-methoxy butanol and derivatives based on propylene glycol, z. B. Ethoxyethyl, methoxypropyl or isopropoxypropanol called.

As reactive diluents (a5), which can be crosslinked with actinic radiation, For example, (meth) acrylic acid and esters thereof, maleic acid and their esters or Monoesters, vinyl acetate, vinyl ethers, vinylureas. Ä. Used. As examples Alkylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, 1,3-butane diol di (meth) acrylate, vinyl (meth) acrylate, allyl (meth) acrylate, glycerol tri (meth) acrylate, Trimethylolpropane tri (meth) acrylate, trimethylolpropane di (meth) acrylate, styrene, vinyltoluene, Divinylbenzene, pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, Dipro pylenglykoldi (meth) acrylate, hexanediol di (meth) acrylate, ethoxyethoxyethyl acrylate, N-vinylpyrrolidone, phenoxyethyl acrylate, dimethylaminoethyl acrylate, hydroxyethyl (Meth) acrylate, butoxyethyl acrylate, isobornyl (meth) acrylate, dimethylacrylamide, and Dicyclopentyl, in EP-A-250 631 and described long-chain linear Diacrylates having a molecular weight of 400 to 4000, preferably from 600 to 2,500. For example, the two acrylate groups may be prepared by a polyoxybutylene be separated. Usable are also 1,12-dodecyl diacrylate and the reaction product 2 moles of acrylic acid with one mole of a dimeric fatty alcohol is generally 36 comprises C atoms. Also suitable are mixtures of these monomers.

are preferred as the reactive diluent (a5) mono- and / or diacrylates such. B. Isobornyl acrylate, hexanediol, tripropylene, Laromer® 8887 the company BASF AG and Actilane® 423 of Akcros Chemicals Ltd., UK, are used. Especially preferably isobornyl acrylate, hexanediol and tripropylene used.

If they are to be used, the reactive diluents (a5) are in an amount of preferably 2 to 70 wt .-%, particularly preferably 10 to 65 wt .-% and in particular 15 to 50 wt .-%, each based on the total amount of the coating material I applied.

In addition, the coating material of at least one customary and known Paint Additive (a6) in effective amounts, ie in amounts preferably up to 20 wt .-%, particularly preferably up to 15 wt .-% and in particular up to 10 wt .-%, each based on the total amount of the coating material I, included.

Examples of suitable coatings additives (a6) are

<ul><li>- UV absorbers;</li><li>- Light stabilizers such as HALS compounds, benzotriazoles or oxanilides;</li><li>- Radical scavengers;</li><li>- Crosslinking catalysts such as dibutyl or lithium decanoate;</li><li>- Slip additives; </li><li>- Polymerization;</li><li>- Defoamers;</li><li>- Emulsifiers, especially nonionic emulsifiers such as alkoxylated alkanols and polyols, phenols and alkylphenols, or anionic emulsifiers, such as Alkali metal salts or ammonium salts of alkanecarboxylic acids, alkanesulfonic acids, and Sulfonic acids of alkoxylated alkanols and polyols, phenols and alkylphenols;</li><li>- Wetting agents such as siloxanes, fluorine compounds, carboxylic monoesters, Phosphoric esters, polyacrylic acids and their copolymers, or polyurethanes;</li><li>- Adhesion promoters such as tricyclodecane;</li><li>- Flow control agents;</li><li>- Film-forming auxiliaries such as cellulose derivatives;</li><li>- Transparent pigments such as silica;</li><li>- Flame retardants or</li><li>- Matting agent.</li></ul>

Further examples of suitable coatings additives (a6) are described in the textbook "Coating Additives" by Johan Bieleman, Wiley-VCH, Weinheim, New York, 1998.,.

Not least, the coating material I, at least one thermally curable containing component (a7) in minor amounts. In the present Invention, "minor amounts" are amounts which the dual do not adversely affect Cure properties of the coating material I, but in advantageously vary. If they are to be used to their share of the Coating material I is generally 40 wt .-%, preferably 35 wt .-% and in particular not exceed 30 wt .-%.

Examples of suitable constituents (a7) are the heat-curable by the Coating materials forth known binders and crosslinking agents.

Examples of suitable binders (a7) are linear and / or branched and / or block, comb and / or random poly (meth) acrylates or acrylate copolymers, Polyesters, alkyds, amino resins, polyurethanes, polylactones, polycarbonates, polyethers, Epoxy resin-amine adducts, (meth) acrylate diols, partially hydrolyzed polyvinyl esters or Polyureas, of which the acrylate copolymers, the polyesters, the polyurethanes, the Polyether and epoxy-amine adducts are advantageous.

Suitable binders (a7), for example under the tradenames Desmophen® 650, 2089, 1100, 670, 1200 or 2017 by Bayer, under the trade names Priplas by the company Uniqema or Pripol®, under the trade names Chempol® polyester or Polyacrylate polyol of the CCP, under the trade names Crodapol® 0-85 or 0-86 of Croda or under the trade name Formrez® ER417 from Witco marketed.

Examples of suitable crosslinking agents (a7) are blocked di- and / or polyisocyanates.

Examples of suitable di- and / or polyisocyanates for preparing the blocked Derivatives (a7) are organic polyisocyanates, insbeso ther so-called paint, with aliphatic, cycloaliphatic, araliphatic and / or aromatically bound free Isocyanate. Preference is given to polyisocyanates having from 2 to 5 isocyanate groups per Molecule and viscosities of from 100 to 10,000, preferably 100 to 5000 and in particular 100 to 2000 mPa.s used (at 23 ° C). Optionally, the Polyisocyanates small amounts of organic solvent, preferably 1 to 25 wt .-%, , Are based on pure polyisocyanate added to as the incorporation of to improve the isocyanate and, optionally, the viscosity of the polyisocyanate to a Value decrease within the abovementioned ranges. suitable as additives Solvent the polyisocyanates include ethoxyethyl, amyl methyl ketone or butyl acetate. Furthermore, the polyisocyanates can in a conventional manner be modified hydrophilic or hydrophobic.

Examples of suitable polyisocyanates include in "Methods of Organic Chemie ", Houben-Weyl, Volume 14/2, 4th Edition, Georg Thieme Verlag, Stuttgart 1963, 61 to 70, and of W. Siefken, Liebigs Annalen der Chemie, Volume 562, pages 75 to 136, described. For example, suitable are the isocyanato polyurethane prepolymers; the at by reacting polyols with an excess of Polyisocyanates may be prepared and are preferably of low viscosity.

Further examples of suitable polyisocyanates are polyisocyanates containing isocyanurate, biuret, allophanate, Iminooxadiazinedione, urethane, urea and / or uretdione Polyisocyanates. Polyisocyanates containing urethane groups, for example by Reacting some of the isocyanate groups with polyols, such. As trimethylolpropane and Glycerol. Preferably aliphatic or cycloaliphatic Polyisocyanates, especially hexamethylene diisocyanate, dimerized and trimerized Hexamethylene diisocyanate, isophorone diisocyanate, 2-isocyanatopropylcyclohexyl isocyanate, Dicyclohexylmethane-2,4'-diisocyanate, dicyclohexylmethane-4,4'-diisocyanate or 1,3- Bis (isocyanatomethyl) cyclohexane, diisocyanates derived from dimer fatty acids, as they sold under the commercial designation DDI 1410 by Henkel, 1,8- Diisocyanato-4-isocyanatomethyl-octane, 1,7-diisocyanato-4-isocyanatomethyl-heptane or 1-isocyanato-2- (3-isocyanatopropyl) cyclohexane or mixtures of these Polyisocyanates.

Very particularly preferred are mixtures of uretdione and / or isocyanurate and / or allophanate groups based on Hexamethylene diisocyanate, such as by catalytic oligomerization of Hexamethylene diisocyanate using suitable catalysts are formed, used. The polyisocyanate constituent may also comprise any desired mixtures the exemplary free polyisocyanates exist.

Examples of suitable blocking agents are known from US patent US-A 4,444,954 blocking agents known as

<ul><li>a) phenols such as phenol, cresol, xylenol, nitrophenol, chlorophenol, ethylphenol, t Butylphenol, hydroxybenzoic acid, esters of this acid, or 2,5-di-tert-butyl-4- hydroxytoluene;</li><li>b) lactams such as ε-caprolactam, δ-valerolactam, γ-Butyrolactam or β-propiolactam;</li><li>c) active methylenic compounds such as diethyl malonate, dimethyl Ethyl or methyl acetoacetate, or acetylacetone;</li><li>d) alcohols, such as methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol, t- Butanol, n-amyl alcohol, t-amyl alcohol, lauryl alcohol, Ethylene glycol monomethyl ether, ethylene glycol, Ethylene glycol, diethylene glycol monomethyl ether, Diethylene, propylene, Methoxymethanol, glycolic acid, glycolic esters, lactic acid, lactic acid esters, Methylolurea, methylolmelamine, diacetone alcohol, ethylene chlorohydrin, Ethylenebromohydrin, 1,3-dichloro-2-propanol, 1,4-cyclohexyldimethanol or acetocyanohydrin;</li><li>e) mercaptans such as butyl mercaptan, hexyl mercaptan, t-butyl mercaptan, t- Dodecyl mercaptan, 2-mercaptobenzothiazole, thiophenol, methylthiophenol or ethylthiophenol;</li><li>f) acid amides such as acetoanilide, Acetoanisidinamid, acrylamide, methacrylamide, Acetic, stearic or benzamide;</li><li>g) imides such as succinimide, phthalimide or maleimide;</li><li>h) amines such as diphenylamine, phenylnaphthylamine, xylidine, N-phenylxylidine, carbazole, Aniline, naphthylamine, butylamine, dibutylamine or butylphenylamine;</li><li>i) imidazoles such as imidazole or 2-ethyl imidazole; </li><li>j) ureas such as urea, thiourea, ethylene urea, ethylene thiourea or 1,3-diphenyl urea;</li><li>k) carbamates such as phenyl N-phenylcarbamate or 2-oxazolidone;</li><li>l) imines such as ethyleneimine;</li><li>m) oximes such as acetone, Formaldoxime, acetaldoxime, acetone oxime, Methyl ethyl diisobutyl, diacetyl, benzophenone or Chlorohexanonoxime;</li><li>n) salts of sulfurous acid such as sodium bisulfite or potassium bisulfite;</li><li>o) hydroxamic as benzyl methacrylohydroxamate (BMH) or allyl methacrylohydroxamate; or</li><li>p) substituted pyrazoles, ketoximes, imidazoles or triazoles; as</li></ul>

Mixtures of these blocking agents, especially dimethylpyrazole and triazoles, Malonates and acetoacetates or dimethylpyrazole and succinimide.

As the crosslinking agent (a7) and tris (alkoxycarbonylamino) triazines of the can general formula 5

be used.

Examples of suitable tris (alkoxycarbonylamino) triazines (a7) are described in the patents US-A-4,939,213, US-A-5,084,541 or EP-A-0624577 described. Especially be the tris (methoxy, tris (butoxy and / or tris (2-ethylhexoxycarbonylamino) triazines used.

Of advantage are the methyl butyl mixed esters, the butyl 2-ethylhexyl mixed esters, and the Butyl ester. They have the advantage over the straight methyl ester of better Solubility in polymer melts, and also tend less toward crystallizing.

In particular, amino resins, examples being melamine resins, as crosslinking agents (A7) used. This can be any suitable for transparent topcoats or clearcoats Aminoplast resin or a mixture of such amino resins are used. In particular, the customary and known amino resins some of whose Methylol and / or methoxymethyl. T. means of carbamate or Allophanate are defunctionalized. Crosslinking agents of this kind are described in Patents US-A-4710542 and EP-B-0 245 700 and in the article by B. Singh and employees' Carbamylmethylated Melamines, Novel Crosslinkers for the Coatings Industry "in Advanced Organic Coatings Science and Technology Series, 1991, Volume 13, Pages 193 to 207.. Moreover, the amino resins may also act as binders (A11) are used in the base color (A1).

Further examples of suitable crosslinking agents (a7) are beta-hydroxyalkylamides such N, N, N ', N'-tetrakis (2-hydroxyethyl) adipamide or N, N, N', N'-tetrakis (2-hydroxypropyl) - adipamide.

Further examples of suitable crosslinking agents (a7) are siloxanes, especially siloxanes with at least one trialkoxy or dialkoxysilane.

Further examples of suitable crosslinking agent (a7) are polyanhydrides, in particular Polysuccinic.

If the coating material I containing a resin (a1) having no functional groups (A12) which component (a7) is mandatorily present in the coating material I.

According to the invention it is of advantage here if the above for this purpose Described binders (a7) are used.

Overall, it is for the coating material according to the invention advantageous if the complementary functional groups (a12) and (a22), in particular hydroxyl and the isocyanate groups, in a molar ratio of OH / NCO of 0.5 to 2: 1, more preferably 0.8 to 1.5: 1, most preferably from 0.8 to 1.2: 1 and be 1: 0.8 to 1.0 in particular.

The coating material I for inventive use may in different Forms. So he can described appropriate choice of its above Constituents are present as a liquid coating material I, which is substantially free of organic solvents and / or water. However it may be, the coating material I to a solution or dispersion of the above-described constituents in water trade and / or organic solvents. Further, the coating material I in appropriate choice of its above-described constituents be a powder clearcoat material I. This powder clearcoat material I may optionally be dispersed in water, whereby a Powder slurry clearcoat I results. In this case, the coating material I, if it is the Reactivity of its components (a1) and / or (a7) on the one hand and (a2) on the other hand permits a its component system. There is however the risk that the above-mentioned components thermally cure prematurely, it is recommended that the coating material I as a two- or interpreted multi-component system in which at least the component (a2) are separated from stored and the other constituents shortly before use to these is added.

In the second process step, the partially cured clearcoat film I another Clearcoat film II of a thermally with actinic radiation, and optionally curable coating material applied II.

Also, the coating material II is a liquid solution, dispersion, powder clearcoat or powder slurry clearcoat I present. For its application, the above come in the methods I described coating material for use. According to the invention it is advantageous to apply the coating material II, in a wet film thickness such that after Curing the clearcoat film II in the inventive clearcoat A a Dry film thickness of preferably 2 to 15, particularly preferably 3 to 10 and in particular from 4 to 8 microns has.

The essential components of the coating material II are nanoparticles, especially those based on silica, alumina and zirconia. They have a particle size &lt;50 nm and have no flatting. To be Favoured Nanoparticles used on the basis of aluminum oxide and zirconium oxide.

Examples of suitable nanoparticles based on pyrogenic silica are Silicas, under the trade name Aerosil® VP8200, VP721 or R972 of Degussa or the trade names Cab O Sil® TS 610 CT 1110F or CT 1110g sold by the company CABOT.

Generally, these nanoparticles are in the form of dispersions in actinic Radiation curable monomers as those described above reactive diluents (a5) marketed. Examples of suitable monomers which present the Use are particularly well suited are alkoxylated pentaerythritol tetra- or triacrylate, ditrimethylolpropane tetra or triacrylate, Dineopentylglykoldiacrylat, Trimethylolpropane, trishydroxyethyl isocyanurate, Dipentaerythritpenta- or -hexaacrylat or hexanediol. In general, these dispersions contain Nanoparticles in an amount, each based on the dispersions, 10 to 80 wt .-% preferably 15 to 70 wt .-%, particularly preferably 20 to 60 wt .-% and in particular 25 to 50 wt .-%.

An example of the present invention particularly suitable dispersion of Nanoparticles, the dispersion under the trade name High Link® OG 103-31 sold by the company Clariant Hoechst.

The dispersions of nanoparticles in the coating material II advantageously in an amount of 2 to 30 wt .-%, particularly preferably 3 to 25 wt .-% and in particular 5 to 20 wt .-%, each based on the total amount of the coating material II, contain.

Furthermore, the coating material II comprising a curable resin to actinic radiation. Examples of suitable curable with actinic radiation resins come from the oligomer and polymer classes, which are described above, in the resin (a1). According to the invention it is advantageous if the resins used in the coating material II contain no functional groups (a12) or (a22). Of these resins, the Urethane (meth) acrylates and the (meth) acrylate oligomers have particular advantages and Therefore according to the invention particularly preferably used.

The resin is advantageously used in an amount of 5 to 90 wt .-%, particularly preferably 10 to 80 wt .-% and in particular 20 to 70 wt .-%, each based on the Total amount of the coating material II, applied.

Moreover, the coating material II, the above, the coating material I described components (a3), (a4), (a5), (a6) and / or (a7) specified therein Amounts.

In the novel procedure in step 3, the Clearcoat films I and II together cured with actinic radiation and thermally. Again, the above come both partial curing of the clearcoat film I Described methods and devices for the application.

In the alternative method of the invention A, which in particular for the Automotive refinish has particular advantages, is or will be the applied Clearcoat film (s) I in the first process step is not partially but completely cured, the methods and apparatus described above for Application come. Subsequently, the outer surface of the clearcoat film (s) I is roughened. Here, the customary and known roughening methods such as grinding come with sandpaper or steel wool or filing or brush into consideration. Thereafter, the second step, the clearcoat film II described above applied and with actinic radiation, and optionally thermally cured, whereby also here again the methods and apparatus described above to apply.

The clear coats described above according to the invention A, which are preferably prepared using the method A according to the invention can also part of the multi-layer coatings to be B. Advantageously, These are prepared using the method B of the invention.

is or are the clearcoat film (s) I in the first step for this purpose not to the primed or unprimed substrates, but at least one thereon located color and / or effect basecoat film III of a thermally and optionally curable with actinic radiation pigmented coating material III applied.

According to the invention, it is advantageous, the clearcoat film (s) I by the wet-on-wet Method on the dried or flashed off, while uncured basecoat film III apply.

Hereinafter, in a first variant of the method B the Basecoat film (s) III and the clearcoat film (s) I partially cured. Thereafter, at third method step the applied clearcoat film II, after which the Basecoat film (s) III, clearcoat film (s) I and II together with clearcoat actinic radiation and thermally cured.

In the second variant of the method B, in the third Process step, the basecoat film (s) III and the clearcoat film (s) I fully cured, after which the outer surface in the fourth method step of Clearcoat film (s) I roughen. Hereinafter, the fifth step, the Clearcoat film II applied and fully cured in the sixth step.

As the coating material III for preparing the basecoat film III are the customary and known basecoat materials, especially aqueous basecoat materials, into consideration.

Examples of suitable water-based materials are known from the patents EP-A-0089497, EP-A-0256540, EP-A-0260447, EP-A-0297576, WO 96/12747, EP-A-0523610, EP-A-0228003, EP-A-0397806, EP-A-0574417, EP-A-0531510, EP-A 0 581 211, EP-A-0708788, EP-A-0593454, DE-A-43 28 092, EP-A-0299148, EP-A-0394737, EP-A-0590484, EP A-0234362, EP-A-0234361, EP-A-0543817, WO 95/14721, EP-A-0521928, EP-A-0522420, EP-A-0522419, EP-A-0649865, EP-A-0536712, EP-A-0596460, EP-A-0596461, EP-A-0584818, EP-A-0669356, EP-A-0634431, EP-A-0678536, EP-A-0354261, EP-A-0424705, WO 97/49745, WO 97/49747, EP-A-0401565, EP-B-0730613 or WO 95/14721 known.

In the process B according to the invention can - as already mentioned - all above in the application, curing and roughening methods coating material I described and devices are used.

The clear coats A inventive and inventive Multilayer coatings B, due to their glassy surface a extremely high resistance to scratching. This advantageous property is supplemented by an excellent profile of optical properties and excellent Weather resistance and chemical resistance. Thereby, motor vehicles, Plastic parts, furniture and other parts for private or industrial use, including coils and containers which clearcoat at least one novel A and / or contain at least one inventive multicoat system B, in their Value, their performance characteristics and their useful life products, which only contain conventional paint, superior.

Examples 1 and 2 and Comparative Example C1

The preparation of inventive clearcoats A (Examples 1 and 2) and a Clearcoat not inventive (Example C1)

In Examples 1 and 2 and in Comparative Example C1 in each case was a Clearcoat film I of a coating material applied to test panels I PMMA, during 6 min and pre-dried by UV radiation with an energy 1-2 milli joules / cm² partially cured. The clearcoat film I was in all cases in a applied wet film thickness such that fully cured in the Clearcoat films of Examples 1 and 2 and of Comparative Experiment V1 a Dry film thickness 25 to 27 microns resulted.

The coating material I consisted of 100 parts by weight of a urethane (meth) acrylate, which is free from hydroxyl groups was (Ebecryl 5129 from UCB), 100 Parts by weight of a polyester polyol (Desmophen® from Bayer AG), 2.5 By weight of a commercial photoinitiator (Irgacure® 819 from Ciba and Lucirin.RTM TPO from BASF AG), 0.6 parts by weight of a commercial UV Absorber and light stabilizer (mixture of Tinuvin® 400 and neutral-HALS of Ciba, as well as a hindered phenol) and 50 parts by weight of commercial oligomeric acrylate containing free isocyanate groups and acrylate (Roskydal® 2545 from Bayer AG). The coating material I was for the application with a suitable organic solvent (mixture of butyl acetate, n-butanol, and Ektapro®) adjusted to spray viscosity.

On the partially cured clearcoat film I of the coating material II was in a wet film thickness such the clearcoat film II applied that complete after Curing a dry film thickness of 4 to 6 .mu.m.

In the case of Example 1, the coating material II consisted of 30 parts by weight of a commercial (meth) acrylate oligomers (Ebecryl IRR351 UCB), 10 Parts by weight of a commercially available reactive diluent (Servocure® RTT 192 Company Servo Delden), 10 parts by weight of a commercial dispersion of nanoparticles in a multifünktionellen monomers (High Link® OG 103-31 by Clariant Hoechst), 2 parts by weight of a commercial photoinitiator (TPO from Lucirin.RTM BASF AG), 1 part by weight of a commercial UV absorber (Cyagard 1164L Company Cytec, and 0.05 parts by weight of a commercial wetting agent siloxane. Of the Coating material I was used for the application with an appropriate organic Solvent (mixture of butyl acetate, n-butanol and Ektapro®) to spray viscosity (Solids content about 30 to 40 wt .-%) set.

The coating material II of Example 2 was similar to that of Example 1, except that herein additionally 10 parts by weight of silicon dioxide (Aerosil®) were contained.

The coating material of example C1 II corresponded to the coating material of the Example 1, except that herein no High Link® OG 103-31 contained.

In Examples 1 and 2 and in Comparative Example C1, the clearcoat films were I and II after a rest period of 6 min at 50 to 60 ° C with UV-radiation (1 to 3 Joules / cm²) And thermally (10 min fully cured at 90 ° C).

The clearcoat films were the abrasion test Taber 5131 with 100 and 500 routes with a Load of one kilogram per arm subjected. Corresponding devices are by the company Erichsen, F-92508 Rueil-Malmaison Cedex, France, available. After the burden of haze according to DIN 67 530 was determined. yet For comparison, the Abrasion resistance pure plastic sheets of PMMA and PC determined. The table gives an Overview of the test results obtained. The comparison of the haze values ​​in the table demonstrates the superior scratch resistance of the clearcoats A invention which are ideally suited to equip sensitive plastic surfaces scratch resistant.

<imgref idrefs="37/1" />table

<imgref idrefs="37/1" />The haze values ​​(loss of light transmission in percent) (Examples 1 and 2) according to the invention and the (comparative experiment C1) not inventive clearcoat films

Further, a clear coat layers according to the invention of Examples 1 and 2 were the relevant to everyday practice key test subject. To this end they were incubated with a BIC® pen with a ball diameter of 2 mm scratched under load. in this connection it was found that clearcoat films of the invention only with a load of 2,000 g were to scratch. The corresponding load is the siloxane Einbrennklarlack, which is used in this test as a standard, at 500 g.