EP2393612B1 - Coating agent for corrosion-resistant coatings - Google Patents

Description

Field of the invention

The present invention relates to coating compositions for corrosion-resistant coatings, in particular for multicoat color and / or effect paint systems.

State of the art

Modern motor vehicles usually have multicoat color and / or effect paint systems. In general, these multicoat paint systems comprise an electrodeposition coating, a surfacer coating, antistonechip primer or functional coating, a color and / or effect basecoat and a clearcoat. The multicoat paint systems are preferably produced by means of what are known as wet-on-wet processes, in which a clearcoat film is applied to a dried, uncured basecoat film, after which at least the basecoat film and the clearcoat film are thermally cured together. The preparation of the electrodeposition coating and the surfacer coating, antistonechip primer or functional layer can also be included in this process.

The surfacer coats, antistonechip primers or functional coatings are crucial for such important technological properties as impact resistance and smoothness and course of the overall finish. The quality of surfacer coats, antistonechip primers or functional coatings is therefore subject to particularly stringent requirements. They must also be able to be produced in a simple and excellently reproducible manner.

The automotive industry continues to strive to reduce the dry film thicknesses of surfacer coats, antistonechip primers or functional coatings in order to reduce raw material and energy costs, without this leading to a deterioration of the performance Property profile of the multi-layer coatings, in particular to a deterioration of UV stability comes.

To solve these problems have from the patent applications DE 44 38 504 A1 . WO 2005/021168 A1 and WO 2006/062666 A1 made important contributions to known methods. In the methods, a substrate is coated with an electrodeposition paint. The resulting electrocoating layer is baked. The electrodeposition coating layer is coated with a first, physically or thermally curable, aqueous basecoat. The resulting first basecoat film is coated with a second, thermally curable, aqueous basecoat without first curing completely. The resulting second basecoat film is coated with a clearcoat without previously fully curing, thereby resulting in a clearcoat film. Subsequently, the first and second basecoat films and the clearcoat film are baked together. The first, physically or thermally curable, aqueous basecoat material contains as binder at least one water-dilutable polyurethane resin, in particular acrylated polyurethanes. The first basecoat may contain, among other things, titanium dioxide as pigment, talc as filler and UV absorber. The first basecoat provides a first basecoat or functional layer capable of substituting the conventional surfacer coatings, antistonechip primers, or functional coatings without loss of significant technological properties of the multi-layer coatings at dry film thicknesses <35 microns, preferably about 15 microns. Furthermore, the use of UV absorbers, in particular UV-absorbing pigments, as in WO 2005/021168 A1 and WO 2006/062666 A1 described that the UV stability of the relevant multi-layer coatings is guaranteed.

If the above-described multicoat paint systems are exposed to a load caused by falling rocks, so in spite of their high stone chip resistance flaking of the entire layer composite, in which the bare metallic substrate is exposed and exposed to corrosion attack. This corrosion manifests itself in the formation of blisters, that is to say blistering of the multicoat system, accompanied by a progressive increase in the area exposed by the rockfall, which is due to the corrosive infiltration of the multicoat system starting from the corrosion on the bare metallic substrate.

There is therefore a need to develop coating compositions for multicoat paint systems in which the exposed by impact impact bare metallic substrate are protected by corrosion inhibitors, which are already present in the composite layer. The anticorrosion agents must on the one hand have sufficiently high mobility in order to reach the exposed metallic substrate, on the other hand be well integrated in the layered composite in order to prevent unnecessary bleeding in moisture cycles by osmotic pressure.

The corrosion inhibitors commonly used in the electrodeposition coating layer are pigmented and added as pigment pastes. Low molecular corrosion inhibitors can only reach the interface between the substrate and the paint during the deposition process and thus be deposited if they bear a positive charge, with such corrosion protection agents generally impairing the properties of the entire paint pool and thus of the paint finish. Due to their particle size, pigment-type corrosion protection agents generally have no or only very little mobility.

In DE 103 00 751 A1 describes coating compositions which may contain up to 5 wt .-%, based on the coating agent, water and / or solvents, which are according to the invention for the direct coating of metals, in particular for the coating of metal bands, determined, but also over a Electrocoating applied could be. The coating compositions are cured with actinic radiation and contain low molecular weight organic corrosion inhibitors and preferably further inorganic anti-corrosive pigments. In addition to the corrosion inhibitors and / or pigments, color pigments may furthermore be present in the coating composition. A multicoat paint system in automotive OEM finishing, as described in the introduction, will not be described.

If a coating agent which is cured with actinic radiation is used for coating an electrodeposition coating layer, in particular via electrodeposition coating layers in automotive OEM finishing, the electrodeposition coating is sensitively damaged by photodegradation, which leads to markedly reduced adhesion of the electrodeposition coating layer and thus to increased corrosive infiltration of the layer Neighborhood leads to the bare metallic substrate, which is just to be avoided by the present invention. Furthermore, the application properties of in DE 103 00 751 A1 can be adjusted to the application conditions only with great effort, in particular with regard to the rheology, as they are necessary for the above-described multicoat paint systems in automotive OEM finishing.

The object of the invention

1. (1) mindestens eine erste Basislackierung aus Basislack (A),
2. (2) bevorzugt mindestens eine zweite Basislackierung aus Basislack (B) und
3. (3) mindestens eine transparente Lackierung aus Klarlack (C), vorzugsweise herstellbar durch sukzessive Applikation mindestens eines thermisch härtbaren, vorzugsweise wäßrigen Basislacks (A), bevorzugt mindestens eines thermisch härtbaren, vorzugsweise wäßrigen Basislacks (B) und mindestens eines Klarlacks (C) auf ein ungrundiertes Substrat oder vorzugsweise auf ein mit mindestens einer nicht oder nur partiell gehärteten Grundierung (G) oder besonders bevorzugt auf ein mit mindestens einer vollständig gehärteten Grundierung (G) zumindest teilweise beschichtetes Substrat, die die Nachteile des Standes der Technik nicht mehr aufweisen. Insbesondere sollte die erfindungsgemäße Mehrschichtlackierung eine gute Haftung zu den benachbarten Lackschichten sowie im Besonderen eine deutlich reduzierte Korrosion nach Schlagbelastung, die durch korrosive Unterwanderung des Mehrschichtverbunds ausgehend von freigelegtem blanken metallischen Substrat ausgelöst wird, aufweisen. Desweiteren sollte die Verbesserung der Korrosionsbeständigkeit insbesondere mit im Basislack (A) gut einarbeitbaren Komponenten erreicht werden. Weiterhin soll der physikalisch oder thermisch härtbare, vorzugsweise wäßrige Basislack (A) in einfacher Weise auf der Basis handelsüblicher, vorzugsweise wäßriger Basislacke bereitgestellt werden können und erste Basislackierungen liefern, die selbst in einer Schichtdicke von etwa 15 µm herkömmliche Füllerlackierungen, Steinschlagschutzgrundierungen oder Funktionsschichten in vollem Umfang ersetzen können, ohne dass die anwendungstechnischen Eigenschaften der Mehrschichtlackierungen, insbesondere der Steinschlagschutz und die UV-Stabilität auch nach Langzeitexposition, nachteilig beeinflusst werden. Dabei sollte das neue Verfahren in bereits vorhandenen Anlagen für die Applikation von Basislacken durch elektrostatische Spritzapplikation und pneumatische Applikation durchgeführt werden können, ohne daß hierfür Umbauten notwendig werden.

It was an object of the present invention to provide coating compositions for corrosion-resistant coatings, in particular for multicoat color and / or effect coatings, preferably on metallic substrates, comprising one another in this sequence,

1. (1) at least one first basecoat of basecoat (A),
2. (2) preferably at least one second basecoat of basecoat (B) and
3. (3) at least one transparent varnish of clearcoat (C), preferably preparable by successive application of at least one thermally curable, preferably aqueous basecoat material (A), preferably at least one thermally curable, preferably aqueous basecoat material (B) and at least one clearcoat material (C) to a non-primed substrate or preferably to one with at least one or not only partially hardened primer (G) or particularly preferably on a substrate at least partially coated with at least one fully cured primer (G), which no longer have the disadvantages of the prior art. In particular, the multi-layer coating according to the invention should have a good adhesion to the adjacent paint layers and in particular a significantly reduced corrosion after impact, which is triggered by corrosive infiltration of the multi-layer composite starting from uncovered bare metallic substrate. Furthermore, the improvement in corrosion resistance should be achieved in particular with the basecoat (A) well incorporated components. Furthermore, the physically or thermally curable, preferably aqueous basecoat (A) is to be provided in a simple manner on the basis of commercially available, preferably aqueous basecoats and first basecoats provide, even in a layer thickness of about 15 microns conventional surfacer coats, antistonechip primers or functional layers in full Scope can replace without adversely affecting the performance characteristics of the multi-layer coatings, especially the stone chip protection and UV stability even after long-term exposure. The new process should be able to be carried out in existing systems for the application of basecoats by electrostatic spray application and pneumatic application, without the need for conversions.

The solution according to the invention

1. (1) mindestens eine erste farb- und/oder effektgebende Basislackierung aus Basislack (A),
2. (2) bevorzugt mindestens eine zweite farb- und/oder effektgebende Basislackierung aus Basislack (B) und
3. (3) mindestens eine transparente Lackierung aus Klarlack (C),

gefunden, vorzugsweise herstellbar durch sukzessive Applikation mindestens eines thermisch härtbaren wäßrigen Basislacks (A), mindestens eines thermisch härtbaren wäßrigen Basislacks (B) und gegebenenfalls mindestens eines Klarlacks (C) auf ein ungrundiertes oder vorzugsweise auf ein mit mindestens einer nicht oder nur partiell gehärteten Grundierung (G) beschichtetes Substrat oder besonders bevorzugt auf ein mit mindestens einer vollständig gehärteten Grundierung (G) zumindest teilweise beschichtetes Substrat und gemeinsame Härtung

1. (a) der resultierenden Naßschichten aus den Basislacken (A) und (B) und gegebenenfalls des Klarlacks (C) oder
2. (b) aus den Basislacken (A) und (B) und gegebenenfalls des Klarlacks (C) sowie gegebenenfalls der nicht oder nur partiell gehärteten Grundierung (G),

bei welcher der Basislack (A)

• (a.1) mindestens ein Bindemittel,
• (a.2) mindestens ein farb- oder effektgebendes Pigment und
• (a.3) mindestens eine korrosionsinhibierende Komponente mit einem Grundkörper (GK1), ausgewählt aus der Gruppe der niedermolekularen Alkyl-, Aryl- Aralkyl- Cycloalkylreste und/oder heterocyclischen Reste,welcher mindestens eine Phosphorsäuregruppe als Ligand (L1) trägt, und/oder mindestens eine korrosionsinhibierende Komponente mit einem Grundkörper (GK2), ausgewählt aus der Gruppe der Alkyl-, Aryl- Aralkyl- Cycloalkylreste, heterocyclische Reste und/oder Polymere, welcher mindestens eine Phosphonsäuregruppe als Ligand (L2) trägt,

enthält.Accordingly, a multicoat color and / or effect coating has been found on substrates comprising, one above the other in this order,

1. (1) at least one first color and / or effect basecoat basecoat (A),
2. (2) preferably at least one second color and / or effect basecoat of basecoat (B) and
3. (3) at least one transparent varnish of clearcoat (C),

found, preferably produced by successive application of at least one thermally curable aqueous basecoat (A), at least one thermally curable aqueous basecoat (B) and optionally at least one clearcoat (C) on a non-primed or preferably on one with at least one not or only partially cured primer (G) coated substrate or, more preferably, to a substrate at least partially coated with at least one fully cured primer (G) and cured together

1. (A) the resulting wet layers of the basecoats (A) and (B) and optionally the clearcoat (C) or
2. (b) from the basecoats (A) and (B) and optionally the clearcoat (C) and, if appropriate, the non-cured or only partially cured primer (G),

in which the basecoat (A)

• (a.1) at least one binder,
• (a.2) at least one color or effect pigment and
• (a.3) at least one corrosion-inhibiting component having a main body (GK1) selected from the group of low molecular weight alkyl, aryl, aralkyl, cycloalkyl radicals and / or heterocyclic radicals which carries at least one phosphoric acid group as ligand (L1), and / or at least one corrosion-inhibiting Component having a main body (GK2) selected from the group of the alkyl, aryl, aralkyl, cycloalkyl radicals, heterocyclic radicals and / or polymers, which carries at least one phosphonic acid group as ligand (L2),

contains.

With regard to the prior art, it was not foreseeable for the skilled person that the objects underlying the present invention, the reduction of the blister corrosion with improved adhesion between base coat of base coat (A) and primer (G) and the free metallic Substrate, could be solved with the aid of the multi-layer coating according to the invention. The thermally curable, aqueous basecoat material (A) used in accordance with the invention could be prepared in a simple manner on the basis of commercially available aqueous basecoats and provided first, color and / or effect basecoats (A) which, even in a layer thickness of <15 .mu.m, are conventional surfacer coats, antistonechip primers or functional layers could replace in full, without the performance properties of the multi-layer coatings, especially the stone chip protection and UV stability were also adversely affected even after long-term exposure. In this case, the aqueous basecoat (A) in existing systems for the application of basecoats by electrostatic spray application and pneumatic spray application could be carried out without this conversions were necessary.

Detailed description of the multicoat system according to the invention and of the method for its application The binder (a.1) of the basecoat (A)

The preferably thermally curable and particularly preferably aqueous basecoat material (A) which is used for the multicoat system described below contains as its essential constituent at least one binder (a.1) which preferably has functional groups (Gr). Particularly preferred functional groups (Gr) are hydroxyl, carbamate, epoxy, amino and / or isocyanate groups, with hydroxyl groups being very particularly preferred as functional groups (Gr). In principle, it is possible to use all thermally curable binders having properties which are known for use in organic and / or aqueous basecoats.

Suitable binders (a.1) for use in the coating compositions according to the invention are described, for example, in the patent applications DE 44 38 504 A1 . EP 0 593 454 B1 . DE 199 48 004 A1 . EP 0 787 159 B1 and WO 2005/021168 A1 described. The preferred are in EP 0 593 454 B1 . EP 0 787 159 B1 . DE 199 48 004 A1 and or WO 2005/021168 A1 used binders described, wherein in addition to these binders even more binders can be used.

The binders (a.1) preferably contain combinations of at least 2 components selected from the group of preferably water-dilutable polyester resins (a.1.1), preferably water-dilutable polyurethane resins (a.1.2) and / or preferably water-dilutable polyacrylate resins (a.1.3).

• (a.1.1.1) Polyole oder ein Gemisch von Polyolen und
• (a.1.1.2) Polycarbonsäuren oder Polycarbonsäureanhydride oder ein Gemisch aus Polycarbonsäure und/oder Polycarbonsäureanhydriden zu einem Polyesterharz mit einer Säurezahl nach DIN EN ISO 3682 von 20 bis 70, vorzugsweise 25 bis 55 mg KOH/g nichtflüchtigen Anteil und einer Hydroxylzahl nach DIN EN ISO 4629 von 30 bis 200, vorzugsweise 45 bis 100 mg KOH/g nichtflüchtigen Anteil umgesetzt werden.

Particularly preferred as component (a.1.1) are those in EP 0 593 454 B1 , Page 8, line 3 to page 9, line 42 used water-dilutable polyester resins. Such polyester resins (a.1.1) are obtainable by:

• (a.1.1.1) Polyols or a mixture of polyols and
• (a.1.1.2) polycarboxylic acids or polycarboxylic acid anhydrides or a mixture of polycarboxylic acid and / or polycarboxylic anhydrides to a polyester resin having an acid number according to DIN EN ISO 3682 of 20 to 70, preferably 25 to 55 mg KOH / g non-volatile content and a hydroxyl value according to DIN EN ISO 4629 from 30 to 200, preferably 45 to 100 mg KOH / g non-volatile content to be implemented.

The components (a.1.1.1) which are preferably used for the preparation of the water-dilutable polyester resins (a.1.1) are in EP 0 593 454 B1 on page 8, lines 26 to 51, the preferred components (a.1.1.2) in EP 0 593 454 B1 on page 8, line 52, to page 9, line 32 described. The preparation of the polyester resins (a.1.1) and their neutralization are in EP 0 593 454 B1 on page 9, lines 33 to 42.

• (a.1.2.1) ein Polyester- und/oder Polyetherpolyol oder ein Gemisch aus solchen Polyester- und/oder Polyetherpolyolen,
• (a.1.2.2) ein Polyisocyanat oder ein Gemisch aus Polyisocyanaten,
• (a.1.2.3) eine Verbindung, die mindestens eine gegenüber Isocyanatgruppen reaktive Gruppe und mindestens eine zur Anionenbildung befähigte Gruppe im Molekül aufweist oder ein Gemisch aus solchen Verbindungen,
• (a.1.2.4) gegebenenfalls mindestens eine Hydroxyl- und/oder Aminogruppen enthaltende organische Verbindung mit einem Molekulargewicht von 40 bis 600 Dalton oder ein Gemisch aus solchen Verbindungen und
• (a.1.2.5) gegebenenfalls eine Verbindung, die mindestens eine gegenüber Isocyanatgruppen reaktive Gruppe und mindestens eine Polyoxyalkylengruppe im Molekül aufweist oder ein Gemisch aus solchen Verbindungen

miteinander umgesetzt werden und das entstandene Reaktionsprodukt wenigstens teilweise neutralisiert wird. Das solchermaßen hergestellte Polyurethanharz weist bevorzugt eine Säurezahl nach DIN EN ISO 3682 von 10 bis 60 mg KOH/g nichtflüchtigen Anteil und eine Hydroxylzahl nach DIN EN ISO 4629 von 5 bis 200, vorzugsweise 10 bis 150 mg KOH/g nichtflüchtigen Anteil auf.Particularly preferred as component (a.1.2) are the in EP 0 593 454 B1 , Page 5, line 42 to page 8, line 2 described water-dilutable polyurethane resins used. Such polyurethane resins (a.1.2) are obtainable by

• (a.1.2.1) a polyester and / or polyether polyol or a mixture of such polyester and / or polyether polyols,
• (a.1.2.2) a polyisocyanate or a mixture of polyisocyanates,
• (a.1.2.3) a compound which has at least one isocyanate-reactive group and at least one group capable of forming anions in the molecule, or a mixture of such compounds,
• (a.1.2.4) optionally at least one hydroxyl and / or amino-containing organic compound having a molecular weight of 40 to 600 daltons or a mixture of such compounds and
• (a.1.2.5) optionally a compound which has at least one isocyanate-reactive group and at least one polyoxyalkylene group in the molecule or a mixture of such compounds

are reacted with each other and the resulting reaction product is at least partially neutralized. The polyurethane resin produced in this way preferably has an acid number according to DIN EN ISO 3682 of 10 to 60 mg KOH / g non-volatile content and a hydroxyl value according to DIN EN ISO 4629 of 5 to 200, preferably 10 to 150 mg KOH / g nonvolatile content.

The components (a.1.2.1) which are preferably used for the preparation of the water-dilutable polyurethane resins (a.1.2) are disclosed in EP 0 593 454 B1 on page 6, lines 6 to 42, the preferred components (a.1.2.2) in EP 0 593 454 B1 on page 6, line 43, to page 7, line 13, very particular preference is given to using polyisocyanates based on isophorone diisocyanate and tetramethylxylene diisocyanate, the components preferably used (a.1.2.3) in EP 0 593 454 B1 on page 7, lines 14 to 30, the preferred components (a.1.2.4) in EP 0 593 454 B1 on page 7, lines 31 to 53, and the preferred components (a.1.2.5) in EP 0 593 454 B1 on page 7, lines 54 to 58 described. The preparation of the polyurethane resins (a.1.1) and their neutralization are in EP 0 593 454 B1 on page 7, line 59, to page 8, line 2 described.

As component (a.1.3) it is possible to use water-dilutable polyacrylate resins, as described, for example, in US Pat EP 0 593 454 B1 to be discribed. Water-dilutable polyacrylate resins which are prepared in the presence of polyurethane prepolymers (a.1.3.1) which optionally have units with polymerizable double bonds are preferred as components (a.1.3).

In a preferred embodiment of the invention, water-dilutable polyurethane-modified polyacrylates (a.1.3) according to the EP 0 787 159 B1 used.

• (a.1.3.a.1) einem im wesentlich carboxylgruppenfreien (Meth)acrylsäureester oder einem Gemisch aus (Meth)acrylsäureestern,
• (a.1.3.a.2) einem ethylenisch ungesättigten Monomeren, das mindestens eine Hydroxylgruppe pro Molekül aufweist und im wesentlichen carboxylgruppenfrei ist oder einem Gemisch aus solchen Monomeren und
• (a.1.3.a.3) einem im wesentlichen carboxylgruppenfreien von (a.1.3.a.1) und (a.1.3.a.2) verschiedenen Monomeren oder einem Gemisch aus solchen Monomeren polymerisiert wird, wobei das Polyurethan-Präpolymer (a.1.3.1) kein vernetztes Polyurethanharz ist,

wobei anschließend in einer zweiten Stufe nach Zugabe eines Gemischs aus

• (a.1.3.b.1) einem mindestens eine Carboxylgruppe pro Molekül tragenden ethylenisch ungesättigten Monomeren oder einem Gemisch aus solchen Monomeren und
• (a.1.3.b.2) einem im wesentlichen carboxylgruppenfreien ethylenisch ungesättigten Monomeren oder einem Gemisch aus solchen Monomeren, weiter polymerisiert wird nachdem mindestens 80 Gew.-% der in der ersten Stufe zugegebenen Monomeren umgesetzt worden sind, und in einer abschließenden Stufe nach Beendigung der Polymerisation das polyurethanmodifizierte Polyacrylat (a.1.3) neutralisiert wird und anschließend in Wasser dispergiert wird.

Such water-dilutable polyurethane-modified polyacrylates (a.1.3) are obtainable in a preferred embodiment in that in a first stage in the presence of a solution of a polyurethane prepolymer (a.1.3.1) which has substantially no polymerizable double bonds, a mixture of

• (a.1.3.a.1) a substantially carboxyl-free (meth) acrylic ester or a mixture of (meth) acrylic esters,
• (a.1.3.a.2) an ethylenically unsaturated monomer which has at least one hydroxyl group per molecule and is essentially free of carboxyl groups or a mixture of such monomers and
• (a.1.3.a.3) is polymerized to a substantially carboxyl-free of (a.1.3.a.1) and (a.1.3.a.2) different monomers or a mixture of such monomers, wherein the polyurethane prepolymer ( a.1.3.1) is not a crosslinked polyurethane resin,

followed by in a second stage after addition of a mixture of

• (a.1.3.b.1) an ethylenically unsaturated monomer carrying at least one carboxyl group per molecule or a mixture of such monomers and
• (a.1.3.b.2) a substantially carboxyl group-free ethylenically unsaturated monomer or a mixture of such monomers is further polymerized after at least 80 wt .-% of the monomers added in the first stage have been reacted, and in a final stage after Termination of the polymerization, the polyurethane-modified polyacrylate (a.1.3) is neutralized and then dispersed in water.

The monomeric components (a.1.3.a.1), (a.1.3.a.2), (a.1.3.a.3), (a.1.3.b.1) and (a.1.3.b. 2) are selected in type and quantity so that the polyacrylate resin obtained from the abovementioned components has an acid number according to DIN EN ISO 3682 of 20 to 100 mg KOH / g nonvolatile content and a hydroxyl number according to DIN EN ISO 4629 of 5 to 200, preferably 10 to 150 mg KOH / g nonvolatile content. The preferred weight proportions of the aforementioned components are in EP 0 787 159 B1 on page 3, lines 4 to 6 described.

The components (a.1.3.1) which are preferably used for the preparation of the water-dilutable polyurethane-modified polyacrylate resins (a.1.3) are described in EP 0 787 159 B1 on page 3, line 38, to page 6, line 13, the preferred components (a.1.3.a.1) in EP 0 787 159 B1 on page 3, lines 13 to 20, the preferred components (a.1..3.a.2) in EP 0 787 159 B1 on page 3, lines 21 to 33, the components preferably used (a.1.3.a.3) in EP 0 787 159 B1 on page 3, lines 34 to 37, the preferred components (a.1.3.b.1) in EP 0 787 159 B1 on page 6, lines 33 to 39, and the preferred components (a.1.3.b.2) in EP 0 787 159 B1 on page 6, lines 40 to 42.

1. (1) mindestens ein Polyurethanpräpolymer, das mindestens eine freie Isocyanatgruppe enthält, mit
2. (2) mindestens einem Addukt, das erhältlich ist, indem man mindestens ein Ethenylarylenmonoisocyanat und mindestens eine Verbindung, enthaltend mindestens zwei isocyanatreaktive funktionelle Gruppen, zur Reaktion bringt,

so miteinander umsetzt, dass mindestens eine isocyanatreaktive funktionelle Gruppe im Addukt verbleibt.In a further embodiment of the invention, water-dilutable polyurethane-modified polyacrylates (a.1.3) which are prepared in the presence of polyurethane prepolymers (a.1.3.1) which have units with polymerizable double bonds are used. Such graft copolymers and their preparation are for example made EP 0 608 021 A1 . DE 196 45 761 A1 . DE 197 22 862 A1 . WO 98/54266 A1 . EP 0 522 419 A1 . EP 0 522 420 A2 and DE 100 39 262 A1 known. In this case, water-dilutable polyurethane-modified polyacrylates (a.1.3) based on graft copolymers are preferably used as described in US Pat DE 199 48 004 A1 are described. The polyurethane prepolymer component (a.1.3.1) is prepared by

1. (1) at least one polyurethane prepolymer containing at least one free isocyanate group, with
2. (2) at least one adduct obtainable by reacting at least one ethenylarylene monoisocyanate and at least one compound containing at least two isocyanate-reactive functional groups,

so reacted that at least one isocyanate-reactive functional group remains in the adduct.

The preferred polyurethane prepolymers used in step (1) above are described in US Pat DE 199 48 004 A1 , Page 4, line 19, to page 8, line 4 described. The preferred adducts used in step (2) above are described in U.S. Pat DE 199 48 004 A1 , Page 8, line 5, to page 9, line 40 described. Preferably, the graft copolymerization is as in DE 199 48 004 A1 , Page 12, line 62, to page 13, line 48, with the in DE 199 48 004 A1 , Page 11, line 30, to page 12, line 60, described monomers. For use in the aqueous basecoat material (A) to be used according to the invention, the graft copolymer (a.1.3) is partially or completely neutralized, whereby a part or all of the potentially anionic groups, ie the acid groups, are converted into an anionic group. Suitable neutralizing agents are known from DE 44 37 535 A1 , Page 6, lines 7 to 16, or the DE 199 48 004 A1 , Page 7, lines 4 to 8, known.

The content of binder (a.1) in the basecoat (A) can vary very widely and depends on the requirements of the individual case. The content of (a.1) in the basecoat (A), based on the solids of the basecoat (A), is preferably from 10 to 90% by weight, in particular from 15 to 85% by weight.

The pigment (a.2) of the basecoat (A)

The basecoat (A) preferably contains at least one color or effect pigment (a.2). Preferably, the pigment (a.2) from the Group consisting of organic and inorganic, coloring, optically effecting, color and optically effecting, fluorescent and phosphorescent pigments, in particular from the group consisting of organic and inorganic, coloring, optically effecting, color and optically effect pigments, and / or whose mixtures are selected. Most preferably, the pigment (a.2) has UV-absorbing constituents.

Examples of suitable effect pigments, which may also be coloring, are metal flake pigments, such as commercial aluminum bronzes, according to DE 36 36 183 A1 chromated aluminum bronzes, and commercial stainless steel bronzes, and non-metallic effect pigments, such as pearlescent or interference pigments, platelet-shaped effect pigments based on iron oxide, which have shades of pink to brown-red, or liquid-crystalline effect pigments. In addition, it will open Rompp Lexikon Lacke and printing inks, Georg Thieme Verlag, 1998, pages 176 , »Effect pigments« and pages 380 and 381 »Metal oxide mica pigments« to »Metallic pigments«, and the patent applications and patents DE 36 36 156 A1 . DE 37 18 446 A1 . DE 37 19 804 A1 . DE 39 30 601 A1 . EP0068311 A1 . EP 0 264 843 A1 . EP 0 265 820 A1 . EP 0 283 852 A1 . EP 0 293 746 A1 . EP 0 417 567 A1 . US 4,828,826 A or US 5,244,649 A directed.

Examples of suitable inorganic color pigments are white pigments such as zinc white, zinc sulfide or lithopone; Black pigments such as carbon black, iron manganese black or spinel black; Colored pigments such as chromium oxide, chromium oxide hydrate green, cobalt green or ultramarine green, cobalt blue, ultramarine blue or manganese blue, ultramarine violet or cobalt and manganese violet, iron oxide red, cadmium sulfoselenide, molybdate red or ultramarine red; Iron oxide brown, mixed brown, spinel and corundum phases or chrome orange; or iron oxide yellow, nickel titanium yellow, chromium titanium yellow, cadmium sulfide, cadmium zinc sulfide, chrome yellow or bismuth vanadate.

Examples of suitable organic color pigments are monoazo pigments, disazo pigments, anthraquinone pigments, quinacridone pigments, quinophthalone pigments, diketopyrrolopyrrole pigments, dioxazine pigments, indanthrone pigments, isoindoline pigments, isoindolinone pigments, azomethine pigments, thioindigo pigments, metal complex pigments, perinone pigments, perylene pigments, phthalocyanine pigments or aniline black.

In addition, it will open Rompp Lexikon Lacke and printing inks, Georg Thieme Verlag, 1998, pages 180 and 181 , "Iron Blue Pigments" to "Iron Oxide Black," pages 451 to 453 "Pigments" to "Pigment Volume Concentration," page 563 "Thioindigo Pigments," page 567, "Titanium Dioxide Pigments," pages 400 and 467, "Naturally Occurring Pigments," Page 459, "Polycyclic Pigments," page 52, "Azomethine Pigments,""AzoPigments," and page 379, "Metal Complex Pigments."

Examples of fluorescent and phosphorescent pigments (daylight pigments) are bis (azomethine) pigments.

The content of the pigments (a.2) in the basecoat (A) can vary very widely and depends primarily on the intensity of the effects, in particular the optical effects, and / or the hue that is or should be adjusted ,

The pigments (a.2) in the basecoat (A) are preferably in an amount of 0.5 to 60, preferably 0.5 to 45, particularly preferably 0.5 to 40, very particularly preferably 0.5 to 35 and in particular 0 , 5 to 30 wt .-%, based on the solids of the basecoat (A) included

The pigments (a.2) are preferably ground in the basecoat (A) to facilitate incorporation with at least one constituent of the binder (a.1) described above. Particularly preferably, the component (a.1.2) of the binder (a.1) described above is used for the trituration.

The basecoat (A) particularly preferably contains at least one UV-absorbing pigment (a.2.1). Preferably, the UV-absorbing pigments (a.2.1) are selected from the group consisting of titanium dioxide pigments and carbon black pigments.

The content of UV-absorbing pigments, in particular titanium dioxide and / or carbon black pigments (a.2.1) in the basecoat (A) may vary and depends on the requirements of the individual case, in particular on the degree of transmission of the UV radiation, which is caused by the further pigments in the basecoat (A) and / or in the further layers of the multicoat paint system according to the invention. The content of titanium dioxide pigment (a.2.1) in the basecoat (A) is preferably based on the solids basecoat material (A), at 0.1 to 50% by weight, in particular 0.5 to 40% by weight. The content of carbon black pigment (a.2.1) in the basecoat (A), based on the solids of the basecoat (A), is preferably 0.005 to 5% by weight, in particular 0.01 to 2% by weight.

The corrosion-inhibiting component (a.3) of the basecoat (A)

The corrosion-inhibiting component (a.3) comprises at least one phosphoric acid group bound to a base body (GK1) as ligand (L1) and / or at least one phosphonic acid group attached to a base body (GK2) as ligand (L2), which has good adhesion to the metal Substrate and with the metal ions released upon corrosion of the substrate can form chelates (to " Chelaten ", see Rompp Online, Georg Thieme Verlag, Stuttgart, New York, 2005, chapter "Chelates The ligand (L) does not lose its chelating property during the thermal curing of the multicoat paint system The ligand (L) inhibits corrosion by complexing and / or covering the metal surface by reducing the corrosion-free portion of the metal surface and / or In addition, component (a.3) can additionally suppress, by means of a buffer effect, the shift in the pH of the aqueous medium at the interface with the metal which is necessary for the corrosion.

Inventive body (GK1), which carry at least one phosphoric acid groups as ligand (L1) are low molecular weight optionally substituted alkyl, aryl, aralkyl, cycloalkyl and / or heterocyclic radicals, in particular pyridines, pyrimidines, pyrazoles, pyrroles, thiophenes, furans, benzimidazoles , Benzothiazoles, benzotriazoles, benzoxazoles, quinolines, isoquinolines, indanes, indenes, benzpyrones, and particularly preferably triazines. Preference is given to optionally substituted alkyl radicals as the main body (GK1), particularly preferably those having 3 to 30, in particular those having 4 to 20 carbon atoms. Low molecular weight basic bodies (GK1) preferably have a molecular weight of less than 750 daltons, more preferably less than 500 daltons.

Inventive body (GK2), which carry at least one phosphonic acid group as a ligand (L2) are low molecular weight alkyl, aryl aralkyl cycloalkyl, heterocyclic radicals and / or polymers containing monomer units with phosphonic acid and weight average molecular weights Mw (determinable by gel permeation according to the Standards DIN 55672-1 to -3) of preferably more than 400 daltons, more preferably more than 600 daltons, and most preferably more than 800 daltons. Low molecular weight basic bodies (GK2) preferably have a molecular weight of less than 750 daltons, more preferably less than 500 daltons. Polymers of monoethylenically unsaturated monomer units which contain at least one monoethylenically unsaturated building block having a phosphonic acid group as ligand (L), particularly preferably vinylphosphonic acid, are preferred as the main body (GK2). Such polymers are for example in WO 2007/125028 A2 described, wherein the copolymers described therein, containing, in addition to the phosphonic acid group-carrying monoethylenically unsaturated monomers, monoethylenically unsaturated monomers with aromatic nitrogen heterocycles, in the context of the invention are very particularly preferred.

If necessary, the main bodies (GK1) or (GK2) can be hydrophilically modified in a known manner. In particular, additional ionic and / or nonionic substituents are introduced into the basic body (GK) for this purpose. In the case of anionic substituents, these are in particular phenolate, carboxylate, thiolate, sulfonate and / or sulfate groups, in the case of cationic substituents ammonium, sulfonium and / or phosphonium groups, and in the case of nonionic groups oligo- or polyalkoxylated, particularly preferably ethoxylated, substituents , Wherein the substituents may also function as additional ligands (L).

The component (a.3) is in the basecoat (A) in amounts of 0.1 to 20, preferably 0.2 to 10, particularly preferably 0.5 to 5 wt .-%, each based on the total weight of the basecoat material (A ), contain.

The other ingredients and the preparation of the basecoat (A)

In a further embodiment of the invention, the basecoat contains (A), preferably at least one talcum component (a.4). The content of talc (a.4) can vary very widely and depends on the requirements of the individual case. Preferably, the content of (a.4), based on the solids of the basecoat material (A), is from 0.1 to 5% by weight, in particular from 0.5 to 2% by weight.

In addition, the basecoat (A) may contain at least one customary and known additive (a.5) in effective amounts. Preferably, the additive (a.5) or the additives (a.5) is selected from the group consisting of various crosslinking agents; from the binders (a.1) different, oligomeric and polymeric binders; from organic and inorganic, colored, transparent, opaque, organic and inorganic pigments, fillers and nanoparticles, organic solvents, drying agents, anti-settling agents, UV absorbers, light stabilizers, radical scavengers, which are different from components (a.2) to (a.4) , Deaerating agents, slip additives, polymerization inhibitors, defoamers, emulsifiers, wetting agents, adhesion promoters, leveling agents, film-forming aids, as well as rheology-controlling additives and flame retardants selected.

Examples of suitable additives (a.5) are disclosed in the German patent application DE 199 48 004 A 1 , Page 14, line 32, to page 17, line 5, wherein preferably amino resins as the predominant or sole crosslinking agent in the basecoat (A) in the in DE 199 48 004 A1 , Page 16, lines 6 to 14, described amounts of 0.1 to 30, preferably 0.3 to 20, particularly preferably 0.5 to 10 wt .-%, each based on the total weight of the basecoat (A) are included ,

Methodically, the preparation of the coating composition according to the invention has no peculiarities, but preferably takes place by mixing the constituents described above and homogenizing the resulting mixtures by means of customary and known mixing methods and apparatuses such as in particular stirred tank, stirred mills, Ultraturrax, in-line dissolvers, static mixers . Sprocket dispersers, pressure relief nozzles and / or Microfluidizer.

The application of the multi-layer coating according to the invention

Although the multicoat system according to the invention can be applied by means of all customary and known methods for the application of liquid coating materials, it is advantageous for the process according to the invention for producing the multicoat systems if the basecoat (A) is prepared by means of the electrostatic spray application (ESTA), preferably with high rotation bells, is applied. Preferably, the coating composition according to the invention is applied in such a wet layer thickness that after curing of the resulting lacquer layer from the basecoat (A) results in a dry film thickness of 6 to 25 .mu.m, preferably 7 to 20 .mu.m, particularly preferably 8 to 18 microns results.

In the preferred process for producing multicoat paint systems, the basecoat material (A) is immediately coated with the thermally curable, preferably aqueous basecoat material (B). Particularly preferably, the basecoat film of the coating composition according to the invention is first flashed off or dried, but not or only partially cured, and then coated with the thermally curable, preferably aqueous basecoat material (B).

Preferably, the thermally curable, aqueous basecoat (B) is a conventional and well-known aqueous basecoat, as for example from the patent application WO 2005/021168 , Page 24, lines 11 to 28 is known.

In a particularly preferred embodiment of the invention, the aqueous basecoat material (B), like the basecoat material (A), contains component (a.3) in amounts of 0.1 to 20, preferably 0.2 to 10, particularly preferably 0.5 to 5 Wt .-%, each based on the total weight of the basecoat (B). Although the basecoat (B) can be applied by means of all customary and known methods for the application of liquid coating materials, it is advantageous for the method according to the invention if it is applied with the aid of the ESTA high rotation. Preferably, it is applied in such a wet layer thickness that, after curing of the resulting basecoat film (B), a dry film thickness of 4 to 25 .mu.m, preferably 5 to 15 .mu.m, more preferably 6 to 10 .mu.m results: Preferably, the basecoat (A) will and the basecoat (B) is applied with such a wet layer thickness that, after curing, a total dry layer thickness of basecoat (A) and basecoat (B) of 10 to 50 μm, preferably 12 to 35 μm, particularly preferably 14 to 28 μm, results.

1. (i) auf ein ungrundiertes Substrat,
2. (ii) vorzugsweise auf ein mit mindestens einer nicht oder nur partiell gehärteten Grundierung (G) beschichtetes Substrat oder
3. (iii) besonders bevorzugt auf ein mit mindestens einer vollständig gehärteten Grundierung (G) beschichtetes Substrat

und gemeinsame Härtung

1. (a) der resultierenden Naßschichten aus dem Basislack (A), dem Basislack (B) und dem Klarlack (C) oder
2. (b) der resultierenden Naßschichten aus dem erfindungsgemäßen Beschichtungsmittel, dem Basislack (B) und dem Klarlack (C) sowie aus gegebenenfalls der nicht oder nur partiell gehärteten Grundierung (G)

hergestellt.The preferred multicoat systems according to the invention are obtained by successive application of the basecoat material (A), preferably at least one thermally curable, preferably aqueous basecoat material (B) and at least one clearcoat material (C).

1. (i) on a non-primed substrate,
2. (ii) preferably to a substrate coated with at least one non-cured or only partially cured primer (G); or
3. (iii) more preferably a substrate coated with at least one fully cured primer (G)

and joint hardening

1. (A) the resulting wet layers of the basecoat (A), the basecoat (B) and the clearcoat (C) or
2. (b) the resulting wet layers comprising the coating composition according to the invention, the basecoat material (B) and the clearcoat material (C), and optionally the unhardened or only partially cured primer (G)

produced.

Processes of this kind are known, for example, from the German patent application DE 44 38 504 A 1 , Page 4, line 62, to page 5, line 20, and page 5, line 59, to page 6, line 9, as well as from the German patent application DE 199 48 004 A 1 , Page 17, line 59, to page 19, line 22, and page 22, lines 13 to 31, i. V. m. Table 1, page 21, known.

In the preferred method of the invention, the coating of the basecoat (A) or preferably the basecoat (B) is immediately coated with the clearcoat (C). Or it is first flashed off or dried, but not or only partially cured, and then coated with the clearcoat (C).

The clearcoat material (C) is a transparent, in particular optically clear, thermally and / or actinic-radiation-curable coating material. Suitable clearcoats (C) are all customary and known one-component (1K), two-component (2K) or multi-component (3K, 4K) clearcoats, powder clearcoats, powder slurry clearcoats or UV curable clearcoats. The clearcoat material (C) selected for the process according to the invention is applied by means of the customary and known application processes, which are adapted to the physical state (liquid or pulverulent) of the clearcoat material (C). Suitable clearcoats and methods for their application are, for example, from the patent application WO 2005/021168 , Page 25, line 27, to page 28, line 23 known.

The substrates can be constructed from a wide variety of materials and combinations of materials. Preferably, they are at least partially made of metals, wherein spatially next to the metallic substrates plastic substrates may be arranged, as may be the case, for example, in plastic attachments, which are joined together with the metal body.

Most preferably, the substrates are composed of metals, in particular of steels.

The substrates can have a wide variety of uses. The substrates are preferably bodies of motor vehicles, in particular cars, motorcycles, trucks and buses, and parts thereof; industrial hardware; Coils, containers and everyday items. In particular, the substrates are car bodies and parts thereof.

As primers (G), all known inorganic and / or organic primers, in particular for metal or plastic, can be used per se. Preferably, customary and known electrodeposition coatings are used as primers (G). The electrodeposition coatings (G) are prepared in a conventional manner from electrophoretically, in particular cathodically, electrodepositable coatings. The resulting electrodeposition coating layers (G) are preferably thermally cured before the application of the basecoat material (A). However, they can also be merely dried and not or only partially cured, after which they are cured together with the other layers of coating material according to the invention, preferably basecoat (B) and clearcoat (C).

In the preferred method of the invention, the applied layers of basecoat (A), basecoat (B) and clearcoat (C) are thermally cured together. If the clearcoat (C) is also curable with actinic radiation, a postcure by irradiation with actinic radiation takes place. If the primer (G) is not yet cured, it is cured in this process step with.

Curing may, after a certain period of rest, also referred to as venting, take place between and after application, if necessary, of the primer, the basecoat (A), the basecoat (B) and finally the clearcoat (C). The rest period may have a duration of 30 seconds to 2 hours, preferably 1 minute to 1 hour and especially 1 to 45 minutes. It serves, for example, for the course and degassing of the paint layers or for the evaporation of volatile constituents. The rest period can be supported and / or shortened by the use of elevated temperatures up to 90 ° C and / or by a reduced air humidity <10 g water / kg air, in particular <5 g / kg air, provided that there are no damage or changes in the paint layers occur, such as premature full networking.

The thermal curing has no special features, but takes place according to the usual and known methods such as heating in a convection oven or irradiation with IR lamps. Here, the thermal curing can also be done gradually. Another preferred curing method is near infrared (NIR) curing. Particularly preferred is a method in which the component water is rapidly removed from the wet layers. Suitable methods of this kind are, for example by Roger Talbert in Industrial Paint & Powder, 04/01, pages 30 to 33 , "Curing in Seconds with NIR", or in Electroplating, Volume 90 (11), pages 3098 to 3100 , »Painting technique, NIR drying every second of liquid and powder coatings«.

Advantageously, the thermal curing takes place at a temperature of 50 to 170, more preferably 60 to 165 and in particular 80 to 150 ° C for a time of 1 minute to 2 hours, more preferably 2 minutes to 1 hour and especially 3 to 45 minutes ,

The resulting finishes are of excellent automotive quality. In addition to excellent stone chip resistance, they have excellent adhesion to the primer (G) and to the following ones Coating layers and in particular an outstanding resistance to corrosive infiltration and resulting Blisterkorrosion the multi-layer composites in the vicinity of bare areas, as they are generated in particular by rockfall on.

Examples Preparation Example 1: Aqueous Polyester Resin Solution (a.1.1)

From 898 parts by weight of neopentyl glycol, 946 parts by weight of hexane-1,6-diol, 570 parts by weight of hexahydrophthalic anhydride, 2107 parts by weight of an oligomeric fatty acid (Pripol ^® 1012 from Uniqema, dimer content at least 97 weight %, Trimers content at most 1 wt .-%, monomer content at most traces) and 946 parts by weight of trimellitic anhydride was in a common solvent of the polyester (a.1.1) with an acid number according to DIN EN ISO 3682 of 32 mg KOH / g nonvolatile content and a hydroxyl number according to DIN EN ISO 4629 is 72 mg KOH / g non-volatile content, prepared in deionized water and with dimethylethanolamine to a pH of 7.6 and with further deionized water to a non-volatile content of 60.0 wt. %, set.

Preparation Example 2.1: First Aqueous Polyurethane Dispersion (a.1.2.1)

From 2017 parts by weight of hexane-1,6-diol, 1074 parts by weight of isophthalic acid and 3627 parts by weight of an oligomeric fatty acid (Pripol ^® 1012 from Uniqema, dimer content at least 97 wt .-% wt, most trimer. 1 -%, monomer content at most traces) was in a common solvent, a polyester pre-product with an acid number according to DIN EN ISO 3682 of 3 mg KOH / g non-volatile content and a hydroxyl number according to DIN EN ISO 4629 of 73 mg KOH / g non-volatile content prepared and to a non-volatile content of 73.0 wt .-% set. 1891 parts by weight of the polyester precursor were heated in a common solvent with 113 parts by weight of dimethylolpropionic acid, 18 parts by weight of neopentyl glycol and 517 parts by weight of isophorone diisocyanate and the reaction was up to an isocyanate content of 0.8 wt .-% , based on the total weight, carried out. Thereafter, 50 parts by weight of trimethylolpropane were added and stirred until no free isocyanate groups were more detectable. The polyurethane with an acid number according to DIN EN ISO 3682 of 25 mg KOH / g non-volatile content was placed in deionized water, the solvent removed and with further deionized water and with dimethylethanolamine to a pH of 7.2 and a non-volatile content of 27.0% by weight.

Preparation Example 2.2 Second Aqueous Polyurethane Dispersion (a.1.2.2)

From 1173 parts by weight of neopentylglycol, 1329 parts by weight of hexane-1,6-diol, 2469 parts by weight of isophthalic acid and 1909 parts by weight of an oligomeric fatty acid (Pripol ^® 1012 from Uniqema, dimer content at least 97 weight %, Trimer content at most 1% by weight, monomer content at most traces) in a common solvent was a polyester precursor having an acid number according to DIN EN ISO 3682 of 3 mg KOH / g nonvolatile content and a hydroxyl number according to DIN EN ISO 4629 of 75 mg KOH / g of nonvolatile matter and adjusted to a non-volatile content of 74.0% by weight. 2179 parts by weight of the polyester precursor were heated in a common solvent with 137 parts by weight of dimethylolpropionic acid, 24 parts by weight of neopentyl glycol and 694 parts by weight of m-tetramethylxylene diisocyanate (m-TMXDI TMXDI ^® (Meta), Cytec Ind. ) and the reaction was carried out to an isocyanate content of 1.35% by weight, based on the total weight. Thereafter, 111 parts by weight of trimethylolpropane were added and stirred until no more free isocyanate groups were detectable. The polyurethane with an acid number according to DIN EN ISO 3682 of 25 mg KOH / g non-volatile content was placed in deionized water, the solvent removed and with further deionized water and with dimethylethanolamine to a pH of 7.4 and a non-volatile content of 31.5% by weight.

Preparation Example 3 Aqueous Dispersion of a Polyurethane-Modified Polyacrylate (a.1.3)

On 922 parts by weight of neopentylglycol, 1076 parts by weight of hexane-1,6-diol, 1325 parts by weight of isophthalic acid and 3277 parts by weight of an oligomeric fatty acid (Pripol ^® 1012 from Uniqema, dimer content at least 97 weight %, Trimer content at most 1% by weight, monomer content at most traces) in a common solvent was a polyester precursor having an acid number according to DIN EN ISO 3682 of 3 mg KOH / g nonvolatile content and a hydroxyl number according to DIN EN ISO 4629 of 78 mg KOH / g of nonvolatile matter and adjusted to a non-volatile content of 73.0% by weight. 4085 parts by weight of the polyester pre-product were in a common solvent with 186 parts by weight of neopentyl glycol and 1203 parts by weight of m-tetramethylxylene diisocyanate (TMXDI ^® (Meta), Cytec Ind.) Was heated and the reaction was up to an isocyanate content of 1.65 wt .-%, based on the total weight, carried out. Thereafter, 214 parts by weight of diethanolamine (2,2'-iminobisethanol) were added and stirred until no more free isocyanate groups were detectable. The polyurethane precursor having an acid number according to DIN EN ISO 3682 of 0.1 mg KOH / g nonvolatile fraction and a hydroxyl number according to DIN EN ISO 4629 was 49 mg KOH / g nonvolatile content was reduced to a nonvolatile content of 59.5 wt .-%, discontinued. In the presence of 1017 parts by weight of the polyurethane precursor was in a first stage in a common solvent, a mixture of 1369 parts by weight of n-butyl acrylate, 919 parts by weight of hydroxyethyl acrylate, 581 parts by weight of cyclohexyl methacrylate and 509 parts by weight Styrene polymerized using common initiators for radical polymerization. Thereafter, in a second stage, a mixture of 273 parts by weight of n-butyl acrylate, 184 parts by weight of hydroxyethyl acrylate, 116 parts by weight of cyclohexyl methacrylate, 225 parts by weight of acrylic acid and 102 parts by weight of styrene using conventional initiators for the radical polymerization polymerized. The polyurethane-modified polyacrylate having an acid number according to DIN EN ISO 3682 of 33.5 mg KOH / g nonvolatile fraction was introduced into deionized water and adjusted to a pH of 7.4 with dimethylethanolamine and to a nonvolatile content of 35.5 wt. -%, set.

Production Example 4: The Preparation of the Basecoat (A)

• (a.3.1.): Korantin SMK (C6- bis C10-Alkylphosphorsäureester, Hersteller Fa. BASF SE)
• (a.3.2.): Vinylphosphonsäuregruppenhaltiges Copolymerisat gemäß Beispiel 1 der WO 2007/125038 A2 .

15.0 parts by weight of a paste of a synthetic sodium-aluminum silicate with layer structure from Laporte (3% in water) were mixed with 25.0 parts by weight of the aqueous dispersion of the polyurethane (a.1.2.1) According to Preparation 2.1, 3.0 parts by weight of the aqueous solution of the polyester resin (a.1.1) according to Preparation Example 1, 3.3 parts by weight of butylglycol, 4.8 parts by weight of a commercial melamine resin (Cymel 327 of the Fa. Cytec), 0.3 parts by weight of a neutralization solution (dimethylethanolamine 10% strength in water), 4.0 parts by weight of the dispersion of the polyurethane-modified polyacrylate (a.1.3) according to Preparation Example 3, 2.7 parts by weight Isopropanol, 2.4 parts by weight of ethylhexanol, 0.6 part by weight of catalyst Nacure 2500 (paratoluenesulphonic acid 25% in isopropanol), 10 parts by weight of a carbon black paste (trituration of 10% flame black in the aqueous dispersion of the polyurethane (a.1.2.2) according to Preparation Example 2.2), 14 parts by weight of a white paste (trituration of 50% titanium dioxide in the aqueous dispersion of the polyurethane (a.1.2.2) according to Preparation Example 2.2), 5.4 parts by weight of deionized water, 1.2 parts by weight of a 1: 1 mixture of a polyurethane thickener (Nopco DSX 1550 from Henkel) mixed with butyl glycol, 6.3 parts by weight of deionized water and 2.0 parts by weight of corrosion inhibitor (a.3.x), the following compounds were used:

• (a.3.1.): Korantin SMK (C6 to C10 alkyl phosphoric acid ester, manufacturer Fa. BASF SE)
• (a.3.2.): Vinylphosphonsäuregruppenhaltiges copolymer according to Example 1 of WO 2007/125038 A2 ,

Subsequently, the basecoat is adjusted to a spray viscosity of 90-100 mPas / 1000 s ^-1 using a commercial Rheomat.

Examples 1 and 2: The preparation of the multicoat paint systems according to the invention and their testing

For Examples 1 to 3, the basecoat material (A) according to Preparation Example 4 containing corrosion-inhibiting substances (a.3.1) and (a.3.2), an aqueous basecoat material (B) (Metallic waterborne basecoat Black Sapphire from BASF Coatings AG), also containing the respective components (a.3.1) and (a.3.2) in a proportion of 2% by weight, based on the basecoat (B), and a commercially available one-component clearcoat material (C) (Protect 2 from Dupont ) used.

For Comparative Example C1, the basecoat material (A) according to Preparation Example 4 and the above basecoat material (B) (Metallic Waterborne Basecoat Black Sapphire from BASF Coatings AG) were used in each case without component (a.3.x).

The substrates used were 20 x 20 cm galvanized steel test panels coated with a conventional and well-known electrocoating primer (G) with a dry film thickness of 20 μm.

In Examples 1 to 3 and in Comparative Example C1, the basecoat material (A) according to Preparation Example 5 was first applied by electrostatic spray application (ESTA) in such a wet layer thickness that after curing a dry film thickness of 15 μm resulted. The resulting layer of the basecoat (A) was flashed off for 4 minutes and then with the aqueous basecoat (B) by coated pneumatic spray application in such a wet film thickness that after curing, a dry film thickness of 7 microns resulted. The paint layers of basecoat (A) and basecoat (B) were dried for 10 minutes at 80 ° C. Thereafter, the clearcoat (C) was applied in such a wet layer thickness, that after curing, a dry film thickness of 40 microns resulted. The clearcoat layer (C) was flashed off for 5 minutes. Subsequently, the layers of basecoat (A), basecoat (B) and clearcoat (C) were cured in a convection oven for 30 minutes at 130 ° C.

The adhesion of the base coat (A) layer to the underlying undercoat (G) and to the overlying base coat (B) layer is excellent.

• Die frisch lackierten Prüflinge mussten nach dem letzten Lackiervorgang mindestens 48 Stunden bei Raumtemperatur ruhen, bevor sie beschossen wurden.

Damage to the test panels (rockfall simulation) was carried out according to the following procedure:

• The freshly painted specimens had to rest for at least 48 hours at room temperature after the last painting process before being bombarded.

The bombardment of the painted specimens was carried out with a stone impact tester Type 508 from Erichsen according to DIN 55996-1. An aluminum tube (inner diameter of 3.4 cm, a length of 26.3 cm at the top and 27.8 cm below and a distance of 2.0 to 2.3 cm from the test specimen (the length of the tube section is on the passage tube of the stone impact tester To direct the bombardment in a targeted and defined manner on a limited circular surface, bombardment was carried out with 50 g of hard-cast shotblasting diamond 4-5 mm from Eisenwerk Würth GmbH Bad Friedrichshall at a pressure of 2 bar To stretch to about 10 seconds, you gave the blasting medium accordingly slow in the running stone impact device.

• Montag:
  • Salzsprühnebelprüfung nach DIN ISO 9227
• Dienstag bis Freitag:
  • Konstantklima bei 40 °C nach DIN ISO 6270-2KK
• Samstag und Sonntag:
  • Regeneration bei 23°C und 50% relativer Luftfeuchte

After loading in the rockfall simulation, the samples were subjected to a KWT climate change test according to VDA-Prüfblatt 621-415 (February 1982), whereby the test subjects went through 15 week cycles and where 1 week cycle was structured as follows:

• Monday:
  • Salt spray test according to DIN ISO 9227
• Tuesday to Friday:
  • Constant climate at 40 ° C according to DIN ISO 6270-2KK
• Saturdays and Sundays:
  • Regeneration at 23 ° C and 50% relative humidity

The corrosion-induced growth rate of the area originally damaged by the rockfall was determined by image analysis. After 9 weeks, the weekly average growth rate was calculated.

Table 1 summarizes the results. It can be seen that the use of the components (a.3) according to the invention results in a significant reduction of the corrosion-induced increase in the damaged area in the samples loaded in the rockfall simulation. Table 1: Results of the climate change tests (KWT) Component (a.3) KWT: Increase in damaged area in% per week (A.3.1) Korantin SMK 1,000 (A.3.2) Vinylphosphonic acid-containing copolymer 0,800 Comparative example - 2,300

Claims (10)

1. Multicoat color and/or effect paint system comprising, lying above one another in this order,

   (1) at least one first basecoat comprising basecoat material (A),

   (2) preferably a second, color and/or effect basecoat comprising basecoat material (B), and

   (3) at least one transparent coating comprising clearcoat material (C),

   characterized in that the basecoat material (A) which forms the first basecoat comprises

   (a.1) at least one binder,

   (a.2) at least one color or effect pigment, and

   (a.3) at least one corrosion-inhibiting component with a parent structure (GK1), selected from the group of low molecular mass alkyl, aryl, aralkyl, and cycloalkyl radicals and/or heterocyclic radicals, which carries at least one phosphoric acid group as ligand (L1), and/or at least one corrosion-inhibiting component with a parent structure (GK2), selected from the group of alkyl, aryl, aralkyl, and cycloalkyl radicals, heterocyclic radicals and/or polymers, which carries at least one phosphonic acid group as ligand (L2).
2. Multicoat color and/or effect paint system according to Claim 1, characterized in that the parent structure (GK1) is an optionally substituted alkyl radical having 3 to 30 carbon atoms.
3. Multicoat color and/or effect paint system according to either of Claims 1 and 2, characterized in that the parent structure (GK2) is a polymer of ethylenically unsaturated monomer units which comprises at least one ethylenically unsaturated unit with a phosphonic acid group as ligand (L2).
4. Multicoat paint system according to any of Claims 1 to 3, characterized in that the basecoat material (A) is an aqueous basecoat material.
5. Multicoat paint system according to any of Claims 1 to 4, characterized in that use is made as binder (a.1) of combinations of at least 2 components selected from preferably water-dilutable polyester resins (a.1.1), preferably water-dilutable polyurethane resins (a.1.2) and/or preferably water-dilutable polyacrylate resins (a.1.3).
6. Multicoat paint system according to any of Claims 1 to 5, characterized in that the component (a.3) is present in the basecoat material (A) in an amount of 0.5% to 5% by weight, based on the total weight of the basecoat material (A).
7. Process for producing multicoat paint systems, comprising

   (1) at least one first basecoat comprising basecoat material (A) according to Claims 1 to 6,

   (2) preferably a second, color and/or effect basecoat comprising basecoat material (B), and

   (3) at least one transparent coating comprising clearcoat material (C),

   by applying the basecoat materials (A) and (B) and where appropriate the clearcoat material (C)

   (i) to an unprimed substrate,

   (ii) preferably to a substrate coated with at least one uncured or partly cured primer (G), or

   (iii) more preferably to a substrate coated with at least one fully cured primer (G)

   and jointly curing the wet films comprising basecoat material (A), basecoat material (B), and clearcoat material (C), and also, where appropriate, the uncured primer (G).
8. Process for producing multicoat paint systems according to Claim 7, characterized in that the basecoat materials (A) and (B) are applied at a wet film thickness such that curing results in a joint dry film thickness of the basecoat material (A) and of the basecoat material (B) of in total 10 to 50 µm.
9. Process for producing multicoat paint systems according to either of Claims 7 and 8, characterized in that the basecoat material (A) is applied with a wet film thickness such that curing results in a dry film thickness of the basecoat material (A) of 6 to 25 µm.
10. Process for producing multicoat paint systems according to any of Claims 7 to 9, characterized in that the basecoat material (B) is applied with a wet film thickness such that curing results in a dry film thickness of the basecoat material (B) of 4 to 25 µm