DE19920801A1 - Highly scratch-resistant multi-layer coating, process for its production and its use - Google Patents

Abstract

The invention relates to highly scratch-resistant multi-layer clear lacquer coatings and multi-layer paint coatings containing the same, for primed or unprimed substrates. Said coatings are produced as follows: (1) At least one clear lacquer layer (I) consisting of one coating agent (I) which can be hardened thermally or by actinic radiation, is applied to the surface of the substrate or wet-on-wet to the surface of a base coat layer (III) and is partially hardened. (2) An additional clear lacquer layer (II) consisting of a coating agent (II) which can be optionally hardened thermally or by actinic radiation and which contains nanoparticles is applied to the surface of the clear lacquer layer(s) (I). (3) Subsequently, the clear lacquer layers I and II and optionally the base coat layer (III) are hardened together thermally and by actinic radiation. In an alternative embodiment, the clear lacquer layers (I) can optionally be completely hardened together with the base coat layers (III) by thermal means or by actinic radiation. According to this embodiment, the exterior surface of the clear lacquer layers (I) is roughened, the clear lacquer layer (II) is applied and then hardened by actinic radiation, or optionally by thermal means.

Description

The present invention relates to a new highly scratch-resistant multilayer clearcoat based on at least two coating materials curable with actinic radiation. The present invention also relates to the use of the new highly scratch-resistant multilayer clearcoat in automotive initial and refinishing, the industrial painting, including coil coating and container coating, the Plastic painting and furniture painting. Furthermore, the present concerns Invention a new process for the production of multilayer clearcoats.

Automotive bodies, plastic parts for automobiles or household appliances and industrial Components are now protected by a clear coat. Here, the Clear varnish can be used as the sole varnish layer or the top layer of one form a multi-layer top coat.

In particular automobile bodies are mostly with a multi-layer Provide top coat structure. Clear varnishes are often applied as the last coating layer. For this come the usual and known one-component (1K), two-component (2K), multi-component (3K, 4K) powder or powder slurry clearcoats or UV-curable Clear varnishes into consideration.

One-component (1K), two-component (2K) or multi-component (3K, 4K) clearcoats are described, for example, in the patents US-A-5,474,811, US-A-5,356,669, US-A- 5,605,965, WO 94/10211, WO 94/10212, WO 94/10213, EP-A-0 594 068, EP-A-0 594 071, EP-A-0 594 142, EP-A-0 604 992, WO 94/22969, EP-A-0 596 460 or WO 92/22615 described.

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

A powder coating which is thermally curable with actinic radiation is from the European patent EP-A-0 844 286 known. It contains an unsaturated one Binder and a second resin copolymerizable therewith and a photoinitiator  and a thermal initiator and is thus thermal and with actinic radiation curable. However, this dual cure powder coating is used as a pigmented top coat, which is thermal on the surface with UV light and in the areas close to the substrate is hardened. Whether this well-known powder coating also for the production of Clear lacquer layers, especially in multi-layer coatings, can be Do not remove the patent specification.

Powder slurry coatings are powder coatings in the form of aqueous dispersions. Such slurries are described, for example, in US Pat. No. 4,268,542 and US Pat German patent applications DE-A-195 18 392.4 and DE-A-196 13 547 and not Pre-published German patent application DE-A-198 14 471.7.

UV-curable clearcoats are known, for example, from the patents EP-A-0 540 884, EP- A-0 568 967 or US-A-4,675,234.

Each of these clear coats has specific strengths and weaknesses. So you get with help these clear coats multi-layer coatings that meet the optical requirements. Meanwhile the scratch-resistant one-component (1K) clearcoats are sometimes not enough weather-resistant, whereas the weather-resistant two-component (2K) - or Multi-component (3K, 4K) clearcoats are often not sufficiently scratch-resistant. Some One-component (1K) clearcoats are scratch-resistant and weather-resistant, but have a Combination with frequently used water-based paints such as surface defects Shrink (wrinkling) on.

Powder clearcoats, powder slurry clearcoats and UV-curable clearcoats, on the other hand, have one not entirely satisfactory interlayer adhesion without the problems of Scratch resistance or the etch resistance would be completely solved.

EP-A-0 568 967 describes a process for producing multi-layer coatings known in which a thermally curable clearcoat layer by the wet-on-wet method is applied to a pigmented basecoat, after which the two layers in the Heat can be cured together. On top of the hardened clear coat then at least one further clear coat based on actinic Radiation-curable coating materials are applied and actinic radiation or  with actinic radiation and thermally cured. This procedure delivers Clear lacquer coatings of high chemical resistance and optical quality. However, it is Scratch resistance unsatisfactory.

In addition, EP-A-0 568 967 discloses a process in which an actinic Radiation-curable coating material applied to the pigmented basecoat and is cured. Then another layer of the same coating material applied and hardened with actinic radiation. The result is a high-gloss one Surface without any noticeable structure, but the clearcoat in question yellows. The scratch resistance also leaves something to be desired.

In recent times, so-called sol-gel clearcoats based on siloxane-containing paint have been used formulations developed by hydrolysis and condensation of silane compounds be preserved. These varnishes, which are used as coatings for coatings on plastics are used, for example, in 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 clear coats give plastic substrates such as B. glasses or motorcycle helmet visors have very good scratch resistance. This scratch resistance is known from the OEM (Original Equipment Manufacturing) clearcoats that are commonly used at Initial painting of vehicles used is not achieved. On the part of The automotive industry is now faced with the requirement of this improved scratch resistance also to the clear lacquer layers used in the painting of automobiles transfer. Above all, the particularly heavily used parts of the Automotive bodies such as bonnets, bumpers, sills or doors in the area of Door handles are better protected.

The replacement of the OEM clear coats or commonly used in automotive painting OEM powder slurry clearcoats through sol-gel clearcoats are not, however, readily possible, because for this they B. are too brittle or because trying to send them to the OEM Adapt requirements, often only poor optical properties (appearance) be achieved. Furthermore, they cannot be applied in thicknesses <8 to 10 µm. In addition, constituents of the sol-gel clear lacquers can be dried and / or hardened  knock away, d. that is, they are absorbed by the substrate, causing the hardness of the subject Clear coats are lost. But above all, the sol-gel clearcoats are too expensive.

The more economical use of sol-gel clear coats as an additional coating about the clearcoats used so far there are adhesion problems within the multilayer clear coat between the clear coat and the sol-gel layer that especially after falling rocks and exposure to condensation. This In some cases the problem is exacerbated by the fact that the liability between the Clear coat and the substrate is affected.

To some extent, these problems can be solved by using the Clear coat, which is to be coated with the sol-gel clear coat, only partially cures, so that the sol-gel coating to a certain extent when curing together can be chemically anchored to the clear coat. However, the second requires Clear coat for their curing a long oven drying time, which is a considerable Disadvantage is.

The object of the present invention is to provide a new multilayer clearcoat to provide which no longer has the disadvantages of the prior art, but easy to manufacture, highly scratch-resistant, weather-resistant, non-yellowing, hard, is flexible and free from surface defects, on all substrates as well as within the Clear varnish has a high adhesion and is in the for an excellent optical overall impression necessary to produce high layer thickness. Besides, it is the object of the present invention a new method of producing such a or multilayer clear lacquer layers of at least two with actinic radiation to provide curable coating materials.

Accordingly, the new highly scratch-resistant multilayer clearcoat A was found for a primed or unprimed substrate, which can be produced by

• 1. at least one clear lacquer layer I from one with actinic radiation and thermal curable coating material T applied to the surface of the substrate and partially cures and  
• 2. a further clear lacquer layer II from one with actinic radiation as well optionally thermally curable coating material II, containing nanoparticles, applied to the surface of the clear lacquer layer (s) I, after which
• 3. the clear lacquer layers I and II together with actinic radiation and thermally hardens.

As an alternative to this, the further new highly scratch-resistant multilayer clearcoat A for a primed or unprimed substrate was found, which can be produced by

• 1. at least one clear lacquer layer I from one with actinic radiation and thermal curable coating material I applied to the surface of the substrate, cures and roughen
• 2. a further clear lacquer layer II from one with actinic radiation as well optionally thermally curable coating material II, containing nanoparticles, applied to the outer surface of the clear lacquer layer (s) I, after which
• 3. the clear lacquer layer II with actinic radiation and optionally thermal hardens.

The two new highly scratch-resistant, multi-layer clear coats A are used in hereinafter referred to as the "clearcoats A according to the invention".

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

• 1. at least one clear lacquer layer I from one with actinic radiation and thermal curable coating material I applied to the surface of the substrate and partially hardens and  
• 2. a further clear lacquer layer II from one with actinic radiation as well optionally thermally curable coating material II, containing nanoparticles, applied to the surface of the clear lacquer layer (s) I, after which
• 3. the clear lacquer layers I and II together with actinic radiation and thermally hardens.

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

• 1. at least one clear lacquer layer I from one with actinic radiation and thermal curable coating material I applied to the surface of the substrate, cures and roughen
• 2. a further clear lacquer layer II from one with actinic radiation as well optionally thermally curable coating material II, containing nanoparticles, applied to the outer surface of the clear lacquer layer (s) I, after which
• 3. the clear lacquer layer II with actinic radiation and optionally thermal hardens.

The two new processes for producing highly scratch-resistant clearcoats A are referred to below as "Process A according to the invention".

In addition, the new highly scratch-resistant color and / or effect multi-layer coating B for a primed or unprimed substrate was found, which can be produced by

• 1. at least one color and / or effect basecoat layer III from one pigmented curable thermally and optionally with actinic radiation Coating material III applied to the surface of the substrate and without harden, dry,  
• 2. at least one clear lacquer layer I from one with actinic radiation and thermal curable coating material I wet-on the surface of the basecoat layer III applied wet and partially cured and
• 3. a further clear lacquer layer II from one with actinic radiation as well optionally thermally curable coating material II, containing nanoparticles, applied to the surface of the clear lacquer layer (s) I, after which
• 4. the basecoat layer (s) III and the clearcoat layers I and II together with actinic radiation and thermally cured.

As an alternative to this, the new highly scratch-resistant multicoat paint and / or effect coating B for a primed or unprimed substrate has also been found, which can be produced by:

• 1. at least one color and / or effect basecoat layer III from one pigmented curable thermally and optionally with actinic radiation Coating material III applied to the surface of the substrate and without harden, dry,
• 2. at least one clear lacquer layer I from one with actinic radiation and thermal curable coating material I wet-on the surface of the basecoat layer III applied wet,
• 3. the basecoat layer III and clearcoat layer (s) I together thermally and with cures actinic radiation,
• 4. roughen the outer surface of the clear lacquer layer (s) I,
• 5. a further clear coat II from a with actinic radiation as well optionally thermally curable coating material II, containing nanoparticles, applied to the outer surface of the clear lacquer layer (s) I, after which  
• 6. the clear lacquer layer II with actinic radiation and optionally thermally hardens.

The new color and / or effect multi-layer coatings B referred to as "multi-layer coatings B according to the invention".

In addition, the new process for producing a highly scratch-resistant color and / or effect multi-layer coating B was found on a primed or unprimed substrate, in which

• 1. at least one color and / or effect basecoat layer III from one pigmented curable thermally and optionally with actinic radiation Coating material III applied to the surface of the substrate and without harden, dry,
• 2. at least one clear lacquer layer I from one with actinic radiation and thermal curable coating material I wet-on the surface of the basecoat layer III applied wet and partially cured and
• 3. a further clear lacquer layer II from one with actinic radiation as well optionally thermally curable coating material II, containing nanoparticles, applied to the surface of the clear lacquer layer (s) I, after which
• 4. the basecoat layer (s) III and the clearcoat layers I and II together with actinic radiation and thermally cured.

As an alternative to this, the further new process for producing a highly scratch-resistant color and / or effect multi-layer coating B was found on a primed or unprimed substrate, in which

• 1. at least one color and / or effect basecoat layer III from one pigmented curable thermally and optionally with actinic radiation Coating material III applied to the surface of the substrate and without harden, dry,  
• 2. at least one clear lacquer layer I from one with actinic radiation and thermal curable coating material I wet-on the surface of the basecoat layer III applied wet,
• 3. the basecoat layer III and clearcoat layer (s) I together thermally and with cures actinic radiation,
• 4. roughen the outer surface of the clear lacquer layer (s) I,
• 5. a further clear coat II from a with actinic radiation as well optionally thermally curable coating material II, containing nanoparticles, applied to the outer surface of the clear lacquer layer (s) I, after which
• 6. the clear lacquer layer II with actinic radiation and optionally thermally hardens.

In the following, the two new processes are called "Process B of the Invention" designated.

In the context of the present invention, the term "thermal hardening" means heat-initiated curing of a layer of paint from a coating material in which Usually a crosslinking agent is used separately. Usually this is referred to by experts as external networking. Are the crosslinking agents in the binders already installed, one speaks of self-crosslinking. According to the invention external networking is an advantage and is therefore preferred.

In the context of the present invention, electron radiation is under actinic radiation or preferably to understand UV radiation. The curing by UV radiation is usually initiated by radical or cationic photoinitiators and is hers Mechanism after radical or cationic photopolymerization.

The thermal and the curing with actinic light in a coating material used together, one speaks of "dual cure".  

In view of the prior art, it was surprising and not for the person skilled in the art predictable that the very complex task underlying the invention with With the help of the clearcoat A according to the invention and that of the invention Multi-layer coating B and the process according to the invention for their production could be solved. It is particularly surprising that not only the interlayer adhesion within the clearcoat A according to the invention, but also the liability to the Basecoat layer III within the multi-layer coating B according to the invention far above the known measure are also improved. The inventive Clear coating A and the multi-layer coating B according to the invention outstanding optical properties, in particular a high fullness, high DOI values, a high Shine and no yellowing. Due to the dual cure hardening, even complex ones can Components and molded parts in their shadow areas in a simple manner completely be cured. In all of this, the clearcoat A and the invention Multi-layer coating B according to the invention of excellent weather and Chemical stability. Last but not least, they are extremely scratch-resistant and resist even treatment with steel wool. Above all, they will not be affected by Devices usually used in car washes damaged.

The clearcoat A according to the invention is excellently suitable for painting a primed or unprimed substrate.

All surfaces to be painted come with a combined hardening using heat and actinic radiation are contemplated, which are e.g. B. metals, plastics, wood, ceramics, stone, textiles, fiber composites, leather, glass, Glass fibers, glass and rock wool, mineral and resin-bound building materials, such as gypsum and Cement slabs or roof tiles. Accordingly, the clearcoat A according to the invention is also suitable for applications outside of automotive painting, especially for paints furniture and industrial painting, including coil coating and containers Coating. In the context of industrial painting, it is suitable for painting practically all parts for private or industrial use such as radiators, Household appliances, small parts made of metal, hubcaps or rims. In particular, the Clear varnish A according to the invention is suitable as a coating for basecoats, preferably in the automotive industry. It is particularly suitable as a clear coat over  Water-based paints based on polyesters, polyurethane resins and aminoplast resins, especially in the context of the multi-layer coating B according to the invention.

With the clearcoat A or the invention Multi-layer paint B can also be primed or non-primed art fabrics such as 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 (short names according to DIN 7728T1) can be painted. The plastics to be painted can of course also be used Polymer blends, modified plastics or fiber-reinforced plastics. It can also for the coating of usually in vehicle construction, in particular motor vehicle construction, used plastics are used.

In the case of non-functionalized and / or non-polar substrate surfaces, these can before coating in a known manner, a pretreatment, such as with a plasma or with flames.

The clearcoat A according to the invention can be produced in a first Method step at least one clear lacquer layer I from one with actinic radiation and thermally curable coating material I applied to the surface of the substrate.

Thus, within the scope of the present invention, only one clear lacquer layer I can be made from the Coating material I are applied. However, there can be two or more of them Clear lacquer layers I are applied. This can be different Coating materials I are used for the structure of the clear lacquer layers I. In the in most cases, however, the desired property profile of the invention Clear coat A achieved with a clear coat layer I.

The clear lacquer layer I is applied in a wet layer thickness that after curing in the finished clearcoat A according to the invention a dry layer thickness of 10 to 100, preferably 15 to 75, particularly preferably 20 to 55 and in particular 20 to 35 μm results.  

The application of coating material I for the purpose of producing the clear lacquer layer I can by all common application methods, such as. B. spraying, knife coating, brushing, Pour, dip or roll. Spray application methods are preferred applied, such as compressed air spraying, airless spraying, high rotation, electrostatic spray application (ESTA), possibly combined with hot spray application such as hot air - hot spray. The applications can be used at temperatures of Max. 70 to 80 ° Celsius can be carried out so that suitable application viscosities can be achieved without a short-term thermal load Change or damage to coating material I and its if necessary reprocessing overspray to be reprocessed. This is how hot spraying can be designed that the coating material I is heated only very briefly in or just before the spray nozzle.

The spray booth used for the application can be used, for example, with a optionally temperature-controlled circulation can be operated with a suitable Absorbent medium for the overspray, e.g. B. the coating material I itself operated becomes.

Application when illuminated with visible light of one wavelength is preferred of more than 550 nm or in the absence of light. This creates a material Change or damage to coating material I and the overspray avoided.

Of course, the application methods described above can also be used for Production of the clear lacquer layer II or the basecoat layer III and, if appropriate further layers of paint used in the process A or B according to the invention become.

According to the invention, the clear lacquer layer I is partially cured after its application. From a methodological point of view, the partial curing does not differ from one usually complete curing of a lacquer layer. It will be here crosslinked only so long that the clear coat I on the one hand for the purposes of Process A or B according to the invention has sufficient dimensional stability and, on the other hand sufficient of the crosslinkable functional groups described below (a11) and (a21) and / or (a12) and (a22) (complementary functional groups) for the Post-crosslinking and for interlayer adhesion. The extent of the partial  Curing can therefore vary widely and depends on the requirements of the each individual case. However, due to its general Expertise and / or based on simple preliminary tests. Preferably 0.5 to 99.5, particularly preferably 1 to 99, very particularly preferably 2 to 90 and in particular 3 to 80 mol% of those present in coating material I. networkable functional groups implemented. It is very particularly preferred if the clear lacquer layer I is still sticky after its partial curing.

According to the invention, clear lacquer layer I can be used with actinic radiation or thermally or with actinic radiation and partially cured thermally. According to the invention it is from Advantage partially harden the clear coat layer I with actinic radiation, because here the Degree of cross-linking can be controlled particularly well via the input of radiation energy can.

The hardening can take place after a certain rest period. It can last for 30 s to 2 h, preferably 1 min to 1 h and in particular 1 min to 30 min. The rest period serves, for example, for the course and for degassing the clear lacquer layer I or Evaporation of volatile components such as solvents, water or carbon dioxide if the coating material was applied with supercritical carbon dioxide as a solvent is. The rest period can be increased by using temperatures up to 80 ° Celsius are supported and / or shortened, provided that no damage or Changes in the clear coat layer I occur, such as a premature complete Networking.

According to the invention, curing with actinic radiation takes place with UV radiation or Electron beams. If necessary, it can be exposed to actinic radiation from others Radiation sources are carried out or supplemented. In the case of electron beams preferably worked under an inert gas atmosphere. This can be done, for example, by feeding of carbon dioxide and / or nitrogen directly to the surface of the clear lacquer layer I be guaranteed.

Even in the case of curing with UV radiation, in order to avoid the formation of ozone, be worked under inert gas.  

For curing with actinic radiation, the usual and well-known Radiation sources and optical auxiliary measures applied. Examples of more suitable Radiation sources are high or low pressure mercury vapor lamps, which optionally doped with lead to open a radiation window up to 405 nm, or Electron beam sources. Their arrangement is known in principle and can Conditions of the workpiece and the process parameters can be adjusted. At Completely shaped workpieces such as automobile bodies cannot be more direct Areas accessible to radiation (shadow areas) such as cavities, folds and others design-related undercuts with spot, small area or all-round emitters connected to an automatic movement device for the irradiation of Cavities or edges (partially) are cured.

The facilities and conditions of these hardening methods are described, for example, in R. Holmes, U. V. and E. B. Curing Formulations for Printing Inks, Coatings and Paints, SITA Technology, Academic Press, London, United Kindom 1984.

Here, the (partial) curing can take place in stages, i. H. through multiple Exposure or exposure to actinic radiation. This can alternate done, d. that is, curing alternately with UV radiation and electron radiation.

The thermal hardening also shows no methodological peculiarities, but takes place according to the usual and known methods such as heating in a forced air oven or Irradiate with IR lamps. As with actinic radiation curing, the thermal curing take place gradually. The thermal curing advantageously takes place at a temperature of 50 to 100 ° C, particularly preferably 80 to 100 ° C and in particular 90 to 100 ° C. for a time of 1 min to 2 h, particularly preferably 2 min up to 1 h and in particular 3 min to 30 min. Are substrates used, which are thermally strong, thermal crosslinking can also take place at temperatures be carried out above 100 ° C. In general, it is recommended to do this Temperatures of 180 ° C, preferably 160 ° C and in particular 140 ° C do not increase exceed.

Thermal curing and curing are combined with actinic radiation these methods can be used simultaneously or alternately.  

If the two hardening methods are used alternately, for example with thermal curing started and ended with actinic radiation curing become. In other cases, it may prove beneficial to start with curing begin and end with actinic radiation. The expert can Hardening method, which is the most advantageous for the individual case due to his general specialist knowledge, if necessary with the help of simple preliminary tests determine.

Of course, the curing methods described above can also be used for Production of the clear lacquer layer II or the basecoat layer III and, if appropriate further layers of paint used in the process A or B according to the invention become.

The one to be used according to the invention for the production of the clear lacquer layer I. Coating material I contains at least one component (a1) with at least two functional groups (a11) which are used for crosslinking with actinic radiation.

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

Furthermore, the component (a1) to be used according to the invention can contain at least one, preferably at least two functional groups (a12) which are complementary functional groups (a22) of component (a2) described below thermal Crosslinking reactions can contain.  

Examples of suitable complementary functional groups (a12) and (a22) result from the following overview, in which R stands for organic groups.

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

The selection of the respective complementary groups (a12) and (a22) is based on one after that they have no undesirable reactions initiated by actinic radiation enter or do not interfere with or inhibit curing with actinic radiation, and to others depending on the temperature range in which the thermal curing should take place. Here, especially with regard to thermally sensitive substrates such as plastics, According to the invention, it is advantageous to choose a temperature range which is 100 ° C. in particular does not exceed 80 ° C. With regard to this framework hydroxyl groups and isocyanate groups as complementary functional groups proven advantageous, which is why they are preferably used according to the invention. Particular advantages result if the hydroxyl groups as functional groups (a12) and the isocyanate groups can be used as functional groups (a22).

If there is no functional group (a12) in the component (a1), in the Coating material I imperatively at least one thermally curable component (a7) will be described in detail below.

Accordingly, the particularly advantageous component (a1) is one with 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 especially three (meth) acrylic groups (a11) contains.  

In the context of the present invention, an oligomeric compound is a Compound understood, which generally repeating on average 2 to 15 Has basic structures or monomer units. Under a polymeric compound on the other hand understood a connection which generally averages at least 10 repeating basic structures or monomer units. Connections of this kind are also known by experts as binders or resins.

In contrast, in the context of the present invention under one low molecular compound to understand a compound which is essentially derived only from a basic structure or a monomer unit. Connections of this kind are generally referred to by experts as reactive thinners.

The polymers or oligomers used as binders (a1) usually have number average molecular weight from 500 to 50,000, preferably from 1,000 to 5,000. They preferably have a double bond equivalent weight of 400 to 2,000, especially preferably from 500 to 900. In addition, they preferably have a viscosity at 23 ° C. from 250 to 11,000 mPa.s. They are preferably used in an amount of 5 to 90 parts by weight. %, particularly preferably 10 to 80% by weight and in particular 15 to 70% by weight, in each case based on the total amount of coating material I applied.

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

The urethane (meth) acrylates (a1) are obtained by reacting a di- or Polyisocyanates with a chain extender from the group of the diols / polyols and / or diamines / polyamines and / or dithiols / polythiols and / or alkanolamines and subsequent reaction of 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 extender, di- or polyisocyanate and hydroxyalkyl ester are preferably chosen so that

• 1. the equivalent ratio of the NCO groups to the reactive groups of the Chain extender (hydroxyl, amino or mercaptyl groups) between 3: 1 and 1: 2, preferably 2: 1, is and
• 2. the OH groups of the hydroxyalkyl esters of the ethylenically unsaturated carboxylic acids in stoichiometric amount in relation to the free isocyanate groups of the Prepolymers of isocyanate and chain extender are present.

It is also possible to prepare the urethane (meth) acrylates (a1) by first using a Part of the isocyanate groups of a di- or polyisocyanate with at least one Hydroxyalkyl ester is implemented and the remaining isocyanate groups then with be implemented with a chain extender. In this case, too Amounts of chain extender, isocyanate and hydroxyalkyl ester chosen so that the Equivalent ratio of the NCO groups to the reactive groups of the Chain extender between 3: 1 and 1: 2, preferably 2: 1 and that Equivalent ratio of the remaining NCO groups to the OH groups of the Hy hydroxyalkyl ester is 1: 1. Of course, all intermediate forms are also these both methods possible. For example, part of the isocyanate groups can be one Diisocyanates are first reacted with a diol, then another Part of the isocyanate groups with the hydroxyalkyl ester and subsequent to it remaining isocyanate groups are reacted with a diamine.

These various manufacturing processes for urethane (meth) acrylates (a1) are known (cf. e.g. B. EP-A-204 161).

The urethane (meth) acrylates (a1) can be made more flexible, for example, by the fact that Corresponding isocyanate-functional prepolymers or oligomers with longer-chain, aliphatic diols and / or diamines, in particular aliphatic diols and / or  Diamines with at least 6 carbon atoms are implemented. This flexibilization reaction can be before or after the addition of acrylic or methacrylic acid to the oligomers or prepolymers are carried out.

The following commercially available polyfunctional aliphatic urethane acrylates may also be mentioned as examples of suitable urethane (meth) acrylates (a1):

• - Crodamer® UVU 300 from Croda Resins Ltd., Kent, Great Britain;
• - Genomer® 4302, 4235, 4297 or 4316 from Rahn Chemie, Switzerland;
• - Ebecryl® 284, 294, IRR351, 5129 or 1290 from UCB, Arzneimittelbos, Belgium;
• - Roskydal® LS 2989 or LS 2545 or V94-504 from Bayer AG, Germany;
• - Viaktin® VTE 6160 from Vianova, Austria; or
• - Laromer® 8861 from BASF AG and modified test products.

This is an example of a suitable polyphosphazene (meth) acrylate (a1) Phosphazene dimethacrylate from Idemitsu, Japan.

The coating material I according to the invention further contains a constituent (a2).

This component (a2) is also a resin in the sense of the above the description of the resins (a1). This is where the resins come from (a2) from the oligomer and polymer classes described above. Are an advantage here the (meth) acrylic functional (meth) acrylic copolymers, which therefore are preferably used according to the invention as resins (a2).

The resins (a2) are preferably used in an amount of 5 to 90% by weight, especially preferably 10 to 80% by weight and in particular 15 to 70% by weight, in each case based on the Total amount of coating material I applied.

The resins (a2) contain at least two, in particular at least three, functional ones Groups (a21) which are used for crosslinking with actinic radiation. Examples Suitable functional groups (a21) to be used according to the invention are functional groups (a11) described above.  

Furthermore, the resins (a2) contain at least one, preferably at least two and in particular at least three functional groups (a22), which of the thermal Serve networking. Examples of suitable functional groups of this type can be found in the Take the overview above. Isocyanate groups are particularly advantageous and are therefore very particularly preferred according to the invention as functional groups (a22) used. Particular advantages result if the resins (a2) contain Isocyanate groups (a22) of 7 to 20% by weight, particularly preferably 8 to 18% by weight and in particular 9 to 17 wt .-%, each based on the resin (a2).

Examples of suitable resins (a2) of the type described above are described, for example, in the patents US-A-5,234,970, EP-A-0 549 116 or EP-A-0 618 244.

The coating material I to be used according to the invention can contain at least one Photoinitiator (a3) included. If the coating material I or the clear lacquer layer I with UV radiation 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 preferably in proportions of 0.1 to 10% by weight, 1 to 8% by weight and in particular 2 to 6 % By weight, based in each case on the total amount of coating material I.

Examples of suitable photoinitiators are those of the Norrish II type, the Mechanism of action on an intramolecular variant of hydrogen Abstraction reactions are based on how they occur in various ways in photochemical Reactions occur (for example, here on Römpp Chemie Lexikon, 9th extended and revised edition, Georg Thieme Verlag Stuttgart, vol. 4, 1991, referenced) or cationic photoinitiators (for example here on Römpp Lexikon Lacke and Printing colors, Georg Thieme Verlag Stuttgart, 1998, pages 444 to 446, referenced), in particular benzophenones, benzoins or benzoin ethers or phosphine oxides. It can also for example those commercially available under the names Irgacure® 184, Irgacure® 1800 and Irgacure® 500 from Ciba Geigy, Grenocure® MBF from Rahn and Lucirin® TPO products available from BASF AG are used.

In addition to the photoinitiators (a3), conventional sensitizers such as anthracene can be used in effective amounts are used.  

Furthermore, the coating material I can at least one initiator of the thermal Networking (a4) included. From 80 to 120 ° C these form radicals, which are the Start crosslinking reaction. Examples of thermolabile free radical initiators are organic peroxides, organic azo compounds or C-C-cleaving initiators such as Dialkyl peroxides, peroxocarboxylic acids, peroxodicarbonates, peroxide esters, hydroperoxides, Ketone peroxides, azodinitriles or benzpinacol silyl ether. C-C cleaving initiators are particularly preferred since there are no gaseous ones during their thermal cleavage Decomposition products are formed, which could lead to faults in the paint layer. If they are used, their amounts are generally between 0.1 and 10 % By weight, preferably 0.5 to 8% by weight and in particular 1 to 5% by weight, in each case based on the total amount of coating material I.

In addition, the coating material I can contain at least one with actinic radiation and / or contain thermally curable reactive diluents (a5).

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

Examples of suitable cyclic monoolefins are cyclobutene, cyclopentene, cyclohexene, Cyclooctene, Cyclohepten, Norbonen or 7-Oxanorbonen.

Examples of suitable acyclic monoolefins are contained in hydrocarbon mixtures which are obtained by cracking in petroleum processing (C _{5 cut} ).

Examples include suitable oligomeric polyols (a5) to be used according to the invention a hydroxyl number (OHZ) of 200 to 450, a number average molecular weight Mn of 400 to 1000 and a mass average molecular weight Mw of 600 to 1100.  

Further examples of suitable thermally crosslinkable reactive diluents (a5) are hyperbranched compounds with a tetrafunctional central group derived from Ditrimethylolpropane, diglycerin, ditrimethylolethane, pentaerythritol, tetrakis (2- hydroxyethyl) methane, tetrakis (3-hydroxypropyl) methane or 2,2-bis-hydroxymethyl butanediol- (1,4) (homopentaerythritol). The preparation of these reactive diluents can be done after the usual and known methods of producing hyperbranched and dendrimeric Connections are made. Suitable synthetic methods are described, for example, in the Patents WO 93/17060 or WO 96/12754 or in the book by G. R. Newkome, C. N. Moorefield and F. Vögtle, "Dendritic Molecules, Concepts, Syntheses, Perspectives", VCH, Weinheim, New York, 1996.

Further examples of suitable reactive diluents (a5) are polycarbonate diols, Polyester polyols, poly (meth) acrylate diols or those containing hydroxyl groups Polyaddition products.

Examples of suitable reactive solvents which are used as reactive diluents (a5) are butyl glycol, 2-methoxypropanol, n-butanol, methoxybutanol, n-propanol, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, Ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, Diethylene glycol monoethyl ether, diethylene glycol diethyl ether, diethylene glycol mo nobutyl ether, trimethylol propane, 2-hydroxypropionic acid ethyl ester or 3-methyl-3-methoxybutanol and derivatives based on propylene glycol, e.g. B. Called ethoxyethyl propionate, isopropoxypropanol or methoxypropylacetate.

As a reactive diluent (a5) which can be crosslinked with actinic radiation, (meth) acrylic acid and its esters, maleic acid and its esters or Half ester, vinyl acetate, vinyl ether, vinyl ureas and the like. 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, vinyl toluene, Divinylbenzene, pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, dipro pylene glycol di (meth) acrylate, hexanediol di (meth) acrylate, ethoxyethoxyethyl acrylate, N-vinyl pyrrolidone, phenoxyethyl acrylate, dimethylaminoethyl acrylate, hydroxyethyl (meth) acrylate, butoxyethyl acrylate, isobornyl (meth) acrylate, dimethylacrylamide and  Dicyclopentyl acrylate, the long-chain linear described in EP-A-250 631 Diacrylates with a molecular weight of 400 to 4000, preferably 600 to 2500. For example, the two acrylate groups can have a polyoxibutylene structure be separated. 1,12-Dodecyl diacrylate and the reaction product can also be used of 2 moles of acrylic acid with one mole of a dimer fatty alcohol, which is generally 36 C atoms. Mixtures of the monomers mentioned are also suitable.

Preferred reactive diluents (a5) are mono- and / or diacrylates, such as, for. B. Isobornyl acrylate, hexanediol diacrylate, tripropylene glycol diacrylate, Laromer® 8887 from the company BASF AG and Actilane® 423 from Akcros Chemicals Ltd., GB. Especially isobornyl acrylate, hexanediol diacrylate and tripropylene glycol diacrylate are preferred used.

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

In addition, the coating material can be at least one common and known Paint additive (a6) in effective amounts, d. H. in amounts preferably up to 20% by weight, particularly preferably up to 15% by weight and in particular up to 10% by weight, in each case based on the total amount of coating material I included.

Examples of suitable paint additives (a6) are

• - UV absorber;
• - Light stabilizers such as HALS compounds, benzotriazoles or oxalanilides;
• - radical scavenger;
• - Crosslinking catalysts such as dibutyltin dilaurate or lithium decanoate;
• - slip additives;  
• - polymerization inhibitors;
• - defoamer;
• - Emulsifiers, especially non-ionic emulsifiers such as alkoxylated alkanols and polyols, phenols and alkylphenols or anionic emulsifiers such as Alkali salts or ammonium salts of alkane carboxylic acids, alkane sulfonic acids, and Sulphonic acids of alkoxylated alkanols and polyols, phenols and Alkylphenols;
• Wetting agents such as siloxanes, fluorine-containing compounds, carboxylic acid semiesters, Phosphoric acid esters, polyacrylic acids and their copolymers or polyurethanes;
• - adhesion promoters such as tricyclodecane dimethanol;
• - leveling agent;
• - film-forming aids such as cellulose derivatives;
• - transparent pigments such as silicon dioxide;
• - flame retardants or
• - matting agents.

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

Last but not least, the coating material I can have at least one thermally curable Component (a7) contained in minor amounts. As part of the present Invention are to be understood by "subordinate sets" sets which the dual Do not adversely affect the cure properties of coating material I, but in vary advantageously. If they are used with, their share in the  Coating material I generally 40 wt .-%, preferably 35 wt .-% and in particular not exceed 30% by weight.

Examples of suitable components (a7) are those of the thermally curable ones Coating materials known binders and crosslinking agents.

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

Suitable binders (a7) are, for example, under the trade names Desmophen® 650, 2089, 1100, 670, 1200 or 2017 from Bayer, under the trade names Priplas or Pripol® from Unigema, under the trade names Chempol® Polyester or Polyacrylate polyol from CCP, under the trade names Crodapol® 0-85 or 0-86 from from Croda or under the trade name Formrez® ER417 from Witco expelled.

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

Examples of suitable di- and / or polyisocyanates for the production of the blocked Derivatives (a7) are organic polyisocyanates, especially so-called lacquer polyisocyanates, with aliphatic, cycloaliphatic, araliphatic and / or aromatically bound, free Isocyanate groups. Polyisocyanates with 2 to 5 isocyanate groups per are preferred Molecule and with viscosities from 100 to 10,000, preferably 100 to 5000 and in particular 100 to 2000 mPa.s (at 23 ° C) used. If necessary, the Polyisocyanates still small amounts of organic solvent, preferably 1 to 25% by weight, based on pure polyisocyanate, are added so as to incorporate the To improve isocyanates and, if necessary, the viscosity of the polyisocyanate to a Lower value within the above ranges. Suitable as an additive Solvents the polyisocyanates are, for example, ethoxyethyl propionate, amyl methyl ketone  or butyl acetate. In addition, the polyisocyanates can be used in a customary and known manner be modified hydrophilic or hydrophobic.

Examples of suitable polyisocyanates are, for example, in "Methods of Organic Chemistry ", Houben-Weyl, volume 14/2, 4th edition, Georg Thieme Verlag, Stuttgart 1963, page 61 to 70, and by W. Siefken, Liebigs Annalen der Chemie, volume 562, pages 75 to 136, described. For example, those containing isocyanate groups are suitable Polyurethane prepolymers; by the reaction of polyols with an excess of Polyisocyanates can be prepared and are preferably low viscosity.

Further examples of suitable polyisocyanates are isocyanurate, biuret, allophanate, Iminooxadiazindone, urethane, urea and / or uretdione groups Polyisocyanates. Polyisocyanates containing urethane groups are exemplified by Implementation of part of the isocyanate groups with polyols, such as. B. trimethylolpropane and Glycerin. Aliphatic or cycloaliphatic are preferred 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, such as them are marketed by the Henkel company under the trade name DDI 1410, 1.8- Diisocyanato-4-isocyanatomethyl-octane, 1,7-diisocyanato-4-isocyanatomethyl-heptane or 1-isocyanato-2- (3-isocyanatopropyl) cyclohexane or mixtures thereof Polyisocyanates used.

Mixtures of uretdione and / or isocyanurate groups are very particularly preferred and / or polyisocyanates based on allophanate groups Hexamethylene diisocyanate, as obtained by catalytic oligomerization of Hexamethylene diisocyanate is formed using suitable catalysts, used. The polyisocyanate constituent can also be made from any mixtures of the free polyisocyanates mentioned as examples.

Examples of suitable blocking agents are the blocking agents known from US Pat. No. 4,444,954, such as

• 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;
• b) lactams, such as ε-caprolactam, δ-valerolactam, γ-butyrolactam or β-propiolactam;
• c) active methylenic compounds, such as diethyl malonate, dimethyl malonate, Ethyl or methyl acetoacetate or acetylacetone;
• 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 monoethyl ether, Ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, Diethylene glycol monoethyl ether, propylene glycol monomethyl ether, Methoxymethanol, glycolic acid, glycolic acid ester, lactic acid, lactic acid ester, Methylol urea, methylol melamine, diacetone alcohol, ethylene chlorohydrin, Ethylene bromohydrin, 1,3-dichloro-2-propanol, 1,4-cyclohexyldimethanol or Acetocyanhydrin;
• e) mercaptans such as butyl mercaptan, hexyl mercaptan, t-butyl mercaptan, t- Dodecyl mercaptan, 2-mercaptobenzothiazole, thiophenol, methylthiophenol or Ethylthiophenol;
• f) acid amides such as acetoanilide, acetoanisidinamide, acrylamide, methacrylamide, Acetic acid amide, stearic acid amide or benzamide;
• g) imides such as succinimide, phthalimide or maleimide;
• h) amines such as diphenylamine, phenylnaphthylamine, xylidine, N-phenylxylidine, carbazole, Aniline, naphthylamine, butylamine, dibutylamine or butylphenylamine;
• i) imidazoles such as imidazole or 2-ethylimidazole;  
• j) ureas such as urea, thiourea, ethylene urea, ethylene thiourea or 1,3-diphenylurea;
• k) carbamates such as phenyl N-phenylcarbamate or 2-oxazolidone;
• l) imines such as ethyleneimine;
• m) oximes such as acetone oxime, formal doxime, acetaldoxime, acetoxime, Methyl ethyl ketoxime, diisobutyl ketoxime, diacetyl monoxime, benzophenone oxime or Chlorohexanone oximes;
• n) salts of sulfurous acid such as sodium bisulfite or potassium bisulfite;
• o) hydroxamic acid esters such as benzyl methacrylohydroxamate (BMH) or Allyl methacrylohydroxamate; or
• p) substituted pyrazoles, ketoximes, imidazoles or triazoles; such as

Mixtures of these blocking agents, in particular dimethylpyrazole and triazoles, Malonic ester and acetoacetic acid ester or dimethylpyrazole and succinimide.

Tris (alkoxycarbonylamino) triazines of the general formula 5 can also be used as crosslinking agents (a7)

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-0 624 577. In particular the tris (methoxy-, tris (butoxy- and / or tris (2-ethylhexoxycarbonylamino) triazines used.

The methyl-butyl mixed esters, the butyl-2-ethylhexyl mixed esters and the are advantageous Butyl ester. These have the advantage over the pure methyl ester of the better ones Solubility in polymer melts and also have less tendency to crystallize.

In particular, aminoplast resins, for example melamine resins, are used as crosslinking agents (a7) can be used. Any suitable for transparent top coats or clear coats can be used Aminoplast resin or a mixture of such aminoplast resins can be used. In particular, the usual and known aminoplast resins come into consideration, their Methylol and / or methoxymethyl groups e.g. T. by means of carbamate or Allophanate groups are defunctionalized. Crosslinking agents of this type are used in the US-A-4 710 542 and EP-B-0 245 700 as well as in the article by B. Singh and co-workers "Carbamylmethylated Melamines, Novel Crosslinkers for the Coatings Industry "in Advanced Organic Coatings Science and Technology Series, 1991, Volume 13, Pages 193 to 207. In addition, the aminoplast resins can also be used as binders (a11) can be used in the base color (A1).

Further examples of suitable crosslinking agents (a7) are beta-hydroxyalkylamides such as 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, in particular siloxanes with at least one trialkoxy or dialkoxysilane group.

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

If the coating material I contains a resin (a1) which has no functional groups (a12), the component (a7) in the coating material I is mandatory.  

According to the invention, it is advantageous if for this purpose the above described binder (a7) can be used.

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

The coating material I to be used according to the invention can be of various types Shapes are available. So he can with a corresponding choice of his described above Components are present as liquid coating material I, which is essentially free of organic solvents and / or water. However, the coating material may I to a solution or dispersion of the ingredients described above in water and / or act organic solvents. Furthermore, the coating material I can Corresponding choice of its constituents described above can be a powder clear coat I. This powder clearcoat I can optionally be dispersed in water, thereby a Powder slurry clearcoat I results. The coating material I, if it is Reactivity of its components (a1) and / or (a7) on the one hand and (a2) on the other hand Be a one-component system. However, there is a risk that the components mentioned crosslink thermally early, it is recommended to use coating material I as a two or To design a multi-component system in which at least component (a2) is separated from the other ingredients stored and only shortly before use to them is added.

In the second process step, another is applied to the partially hardened clear coat layer I. Clear lacquer layer II from one with actinic radiation and optionally thermal curable coating material II applied.

Coating material II can also be used as a liquid, solution, dispersion or powder clearcoat or powder slurry clearcoat I are present. For his application come the above the methods described for coating material I for use. It is according to the invention advantageous to apply the coating material II in a wet layer thickness that after the Hardening the clear coat layer II in the clear coat A according to the invention  Dry layer thickness of preferably 2 to 15, particularly preferably 3 to 10 and in particular has 4 to 8 microns.

The essential components of coating material II are nanoparticles, in particular those based on silicon dioxide, aluminum oxide and zirconium oxide. You point have a particle size <50 nm and have no matting effect. To be favoured Nanoparticles based on aluminum oxide and zirconium oxide are used.

Examples of suitable nanoparticles based on silicon dioxide are pyrogenic Silicon dioxides, which under the trade name Aerosil® VP8200, VP721 or R972 from from Degussa or the trade names Cab O Sil® TS 610, CT 1110F or CT 1110G are distributed by the company CABOT.

Generally, these nanoparticles are in the form of dispersions with actinic Radiation-curable monomers such as the reactive diluents (a5) described above expelled. Examples of suitable monomers which are suitable for the present Are particularly suitable for use, are alkoxylated pentaerythritol tetra or triacrylate, ditrimethylolpropane tetra- or triacrylate, dineopentyl glycol diacrylate, Trimethylolpropane triacrylate, trishydroxyethyl isocyanurate triacrylate, dipentaerythritol penta- or hexaacrylate or hexanediol diacrylate. In general, these dispersions contain the Nanoparticles in an amount of 10 to 80% by weight, based on the dispersions, preferably 15 to 70% by weight, particularly preferably 20 to 60% by weight and in particular 25 to 50% by weight.

An example of a dispersion of Nanoparticles is the dispersion, which is sold under the trade name High Link® OG 103-31 is distributed by Clariant Hoechst.

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

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

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

In addition, the coating material II can the above for the coating material I described components (a3), (a4), (a5), (a6) and / or (a7) in the specified therein Amounts included.

In the procedure according to the invention in step 3, the Clear lacquer layers I and II together with actinic radiation and thermally cured. The partial curing of the clear lacquer layer I mentioned above also occurs here described methods and devices for use.

In the alternative method A according to the invention, which is particularly suitable for Automotive refinishing has special advantages, will or will be applied Clear coat layer (s) I in the first step of the process, not partially but completely cured using the methods and devices described above for Application come. The outer surface of the clear lacquer layer (s) I roughened. Here are the usual and known roughening methods such as grinding with sandpaper or steel wool or files or brushes. After that, in second process step applied the clear coat layer II described above and with actinic radiation and optionally thermally cured, again here the methods and devices described above are used.  

The clear coat layers A according to the invention described above, which can be produced preferably with the aid of process A according to the invention also be part of the multi-layer coatings B according to the invention. Advantageously these are produced using the method B according to the invention.

For this purpose, the clear coat layer (s) I will be in the first process step not on the primed or unprimed substrates, but on at least one of them located color and / or effect basecoat layer III from a thermal and optionally pigmented coating material III curable with actinic radiation applied.

According to the invention, it is advantageous to coat the clear lacquer (s) I after the wet-on-wet Process on the dried or vented, but not hardened basecoat layer III to apply.

According to this, in a first variant of method B according to the invention Base coat layer (s) III and the clear coat layer (s) I partially cured. Then in third process step applied the clear coat layer II, after which the Base coat layer (s) III, clear coat layer (s) I and clear coat layer II together with actinic radiation and thermally cured.

In the second variant of method B according to the invention, in the third Process step the basecoat layer (s) III and the clearcoat layer (s) I completely cured, after which the outer surface in the fourth process step Clear coat (s) I roughened. After that, in the fifth process step Clear coat II applied and fully cured in the sixth process step.

The usual coating materials III for the production of the basecoat film III and known basecoats, especially waterborne basecoats.

Examples of suitable waterborne basecoats can be found in the patents EP-A-0 089 497, EP-A-0 256 540, EP-A-0 260 447, EP-A-0 297 576, WO 96/12747, EP-A-0 523 610, EP-A-0 228 003, EP-A-0 397 806, EP-A-0 574 417, EP-A-0 531 510, EP-A-0 581 211, EP-A-0 708 788, EP-A-0 593 454, DE-A-43 28 092, EP-A-0 299 148, EP-A-0 394 737, EP-A-0 590 484, EP-  A-0 234 362, EP-A-0 234 361, EP-A-0 543 817, WO 95/14721, EP-A-0 521 928, EP-A-0 522 420, EP-A-0 522 419, EP-A-0 649 865, EP-A-0 536 712, EP-A-0 596 460, EP-A-0 596 461, EP-A-0 584 818, EP-A-0 669 356, EP-A-0 634 431, EP-A-0 678 536, EP-A-0 354 261, EP-A-0 424 705, WO 97/49745, WO 97/49747, EP-A-0 401 565, EP-B-0 730 613 or WO 95/14721 known.

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

The clear lacquer layers A according to the invention and those according to the invention Multi-layer coatings B have a glassy surface extraordinarily high scratch resistance. This advantageous property is supplemented by an excellent optical property profile as well as an excellent Weather resistance and chemical resistance. This means motor vehicles, Plastic parts, furniture and other parts for private or industrial use, including coils and containers which have at least one clearcoat A and / or contain at least one multilayer coating B according to the invention in their Value, their usage properties and their service life products which only contain conventional paint finishes, superior.

Examples 1 and 2 and comparative experiment V1 The production of clearcoats A according to the invention (Examples 1 and 2) and one clearcoat not according to the invention (comparative test V1)

In Examples 1 and 2 and in comparative experiment V1, a clear lacquer layer I made of a coating material I was applied to test panels made of PMMA, predried for 6 min and partially cured by UV radiation with an energy of 1 to 2 millijoules / cm ² . The clear lacquer layer I was applied in all cases in such a wet layer thickness that a dry layer thickness of 25 to 27 μm resulted in the completely hardened clear lacquer layers of examples 1 and 2 and comparative experiment V1.

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

The coating material II was applied to the partially cured clearcoat layer I in a applied such a wet layer thickness of the clear coat layer II that after the complete Curing a dry film thickness of 4 to 6 microns resulted.

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

The coating material II of Example 2 corresponded to that of Example 1, except that this contained an additional 10 parts by weight of silicon dioxide (Aerosil®).

Coating material II of comparative experiment V1 corresponded to the coating material of Example 1, only that no High Link® OG 103-31 was included.  

In Examples 1 and 2 and in Comparative Experiment V1, the clearcoat layers I and II were after a rest period of 6 min at 50 to 60 ° C with UV radiation (1 to 3 joules / cm ² ) and thermally (10 min at 90 ° C) fully cured.

The clear lacquer layers were the abrasion test Taber 5131 with 100 and 500 tours with one Subjected to a load of one kilogram per arm. Appropriate devices are available from ERICHSEN, F-92508 Rueil-Malmaison, Cedex, France. To the load was determined according to DIN 67 530. For comparison, the Abrasion resistance of pure plastic sheets made of PMMA and PC determined. The table gives one Overview of the measurement results obtained. The comparison of the Haze values in the table demonstrates the superior scratch resistance of the clear lacquer layers A according to the invention, which are excellently suited for making sensitive plastic surfaces scratch-resistant.

table

The haze values (losses in light transmittance in percent) of the inventive (examples 1 and 2) and of the non-inventive (comparative experiment V1) clearcoat layers

Furthermore, the clear lacquer layers of Examples 1 and 2 according to the invention were key test relevant for everyday practice. To that end, they were using a BIC® pin with a ball of 2 mm diameter scratched under load. Here it was found that the clear lacquer layers according to the invention only from a load of 2,000 g had to be scratched. The corresponding burden lies with the siloxane-containing Stoving clear varnish, which is used as standard in this test, at 500 g.

Claims (14)

1. Highly scratch-resistant multilayer clearcoat A for a primed or unprimed substrate, can be produced by

• 1. at least one clear lacquer layer I made of an actinic radiation and thermally curable coating material I applied to the surface of the substrate and partially cured and
• 2. A further clear lacquer layer II made of a coating material II containing nanoparticles, which is curable with actinic radiation and optionally thermally curable, is applied to the surface of the clear lacquer layer (s) I, after which
• 3. the clear lacquer layers I and II cure together with actinic radiation and thermally.

2. Highly scratch-resistant multilayer clearcoat A for a primed or unprimed substrate, can be produced by:

• 1. applied, cured and roughened at least one clear lacquer layer I made of a coating material I with actinic radiation and thermally curable coating material,
• 2. a further clear coat II made of a coating material II containing nanoparticles, which is curable with actinic radiation and optionally thermally curable, is applied to the outer surface of the clear coat (s) I, after which
• 3. the clear lacquer layer II with actinic radiation and optionally thermally cured.

3. Highly scratch-resistant color and / or effect multi-layer coating B for a primed or unprimed substrate, can be produced by

• 1. applied at least one color and / or effect basecoat layer III composed of a pigmented coating material III which is curable thermally and optionally with actinic radiation to the surface of the substrate and dries without curing,
• 2. at least one clear lacquer layer I made of a coating material I which is actinic radiation and thermally curable is applied wet-on-wet to the surface of the base lacquer layer III and partially cured and
• 3. A further clear lacquer layer II made of a coating material II containing nanoparticles, which is curable with actinic radiation and optionally thermally curable, is applied to the surface of the clear lacquer layer (s) I, after which
• 4. The basecoat layer (s) III and the clearcoat layers I and II cure together with actinic radiation and thermally.

4. Highly scratch-resistant color and / or effect multilayer coating B for a primed or unprimed substrate, can be produced by

• 1. applied at least one color and / or effect basecoat layer III composed of a pigmented coating material III which is curable thermally and optionally with actinic radiation to the surface of the substrate and dries without curing,
• 2. at least one clear lacquer layer I of a coating material I which is actinic radiation and thermally curable is applied wet-on-wet to the surface of the base lacquer layer III,
• 3. the basecoat layer III and clearcoat layer (s) I cure together thermally and with actinic radiation,
• 4. roughen the outer surface of the clear lacquer layer (s) I,
• 5. a further clear coat II made from a coating material II containing actinic radiation and optionally thermally curable, containing nanoparticles, is applied to the outer surface of the clear coat (s) I, after which
• 6. the clear lacquer layer II with actinic radiation and optionally thermally cured.

5. A process for producing a highly scratch-resistant multilayer clearcoat A on a primed or unprimed substrate, in which one

• 1. at least one clear lacquer layer I made of an actinic radiation and thermally curable coating material I applied to the surface of the substrate and partially cured and
• 2. A further clear lacquer layer II made of a coating material II containing nanoparticles, which is curable with actinic radiation and optionally thermally curable, is applied to the surface of the clear lacquer layer (s) I, after which
• 3. the clear lacquer layers I and II cure together with actinic radiation and thermally.

6. A process for producing a highly scratch-resistant multilayer clearcoat A on a primed or unprimed substrate, in which

• 1. applied, cured and roughened at least one clear lacquer layer I made of a coating material I with actinic radiation and thermally curable coating material,
• 2. a further clear coat II made of a coating material II containing nanoparticles, which is curable with actinic radiation and optionally thermally curable, is applied to the outer surface of the clear coat (s) I, after which
• 3. the clear lacquer layer II with actinic radiation and optionally thermally cured.

7. A process for producing a highly scratch-resistant multi-layer paint and / or effect paint B on a primed or unprimed substrate, in which

• 1. applied at least one color and / or effect basecoat layer III composed of a pigmented coating material III which is curable thermally and optionally with actinic radiation to the surface of the substrate and dries without curing,
• 2. at least one clear lacquer layer I made of a coating material I which is actinic radiation and thermally curable is applied wet-on-wet to the surface of the base lacquer layer III and partially cured and
• 3. A further clear lacquer layer II made of a coating material II containing nanoparticles, which is curable with actinic radiation and optionally thermally curable, is applied to the surface of the clear lacquer layer (s) I, after which
• 4. The basecoat layer (s) III and the clearcoat layers I and II cure together with actinic radiation and thermally.

8. A process for producing a highly scratch-resistant multi-layer paint and / or effect paint B on a primed or unprimed substrate, in which

• 1. applied at least one color and / or effect basecoat layer III composed of a pigmented coating material III which is curable thermally and optionally with actinic radiation to the surface of the substrate and dries without curing,
• 2. at least one clear lacquer layer I composed of a coating material I which is curable with actinic radiation and thermally curable is applied wet-on-wet to the surface of the base lacquer layer III,
• 3. the basecoat layer III and clearcoat layer (s) I cure together thermally and with actinic radiation,
• 4. roughen the outer surface of the clear lacquer layer (s) I,
• 5. a further clear coat II made from a coating material II containing actinic radiation and optionally thermally curable, containing nanoparticles, is applied to the outer surface of the clear coat (s) I, after which
• 6. the clear lacquer layer II with actinic radiation and optionally thermally cured.

9. The clear coat A according to claim 1 or 2, the multi-coat paint B after Claim 3 or 4, the process for the preparation of the clearcoat A after Claim 5 or 6 and the method for producing the multilayer coating B according to claim 7 or 8, characterized in that the coating material II Nanoparticles based on silicon dioxide, aluminum oxide and zirconium oxide contains. 10. The clear coat A according to one of claims 1, 2 or 9, the multi-coat paint B according to one of claims 3, 4 or 9, the process for producing the clear coat A according to one of claims 5, 6 or 9 and the process for producing the Multi-layer coating B according to one of claims 7 to 9, characterized in that the coating material I

• 1. with at least one component
• 2. at least two functional groups which are used for crosslinking with actinic radiation, and if appropriate
• 3. at least one functional group which can undergo thermal crosslinking reactions with a complementary functional group (a22) in component (a2),

and

• 1. with at least one component
• 2. at least two functional groups which are used for crosslinking with actinic radiation, and
• 3. at least one functional group which can undergo thermal crosslinking reactions with a complementary functional group (a12) in component (a1),

and if necessary

• 1. at least one photoinitiator,
• 2. at least one initiator of the thermal crosslinking,
• 3. at least one reactive diluent curable with actinic radiation and / or thermally curable,
• 4. at least one paint additive and / or
• 5. at least one thermally curable component,

with the proviso that the coating material I contains at least one thermally curable component (a7) if the component (a1) has no functional group (a12). 11. The clear coat A, the multi-coat paint B, the process for manufacturing the clear coat A or the process for producing the multi-coat paint B according to claim 10, characterized in that it is the functional Groups (a11) and (a21) around olefinically unsaturated groups or epoxy groups, especially olefinically unsaturated groups, for the functional groups (a12) around hydroxyl groups and in the complementary functional groups (a22) and Isocyanate groups. 12. The clear coat A, the multi-coat paint B, the manufacturing process the clear coat A or the process for producing the multi-coat paint B according to claim 10 or II, characterized in that it is in the Component (a1) is a urethane (meth) acrylate and component (a2) is a (Meth) acrylate-functional (meth) acrylate copolymer with free isocyanate groups and / or is a (meth) acrylate-functional polyisocyanate. 13. The use of the clearcoat A according to one of claims 1, 2 or 9 to 12, the multicoat paint system B according to one of claims 3, 4 or 9 to 12, the method for producing the clearcoat A according to one of claims 5, 6 or 9 to 12 or the method for producing the multilayer coating B according to one of claims 7 to 12 in automotive OEM painting, the Automotive refinishing, plastic painting, furniture painting and industrial painting, including coil coatings and container coatings. 14. Motor vehicles, plastic parts, furniture and other parts for private or industrial use, including coils and containers, containing at least one Clear coating A according to one of claims 1, 2 or 9 to 12, at least one Multi-layer coating B according to one of claims 3, 4 or 9 to 12, at least one using the method according to one of claims 5, 6 or 9 to 12 Clear varnish A and / or at least one produced using the method Multi-layer coating B produced according to one of Claims 7 to 12.