Polyurethane coating material composition, multi-stage coating methods

1. A nonaqueous coating material composition comprising

(A) at least one polyhydroxyl group-containing compound,

(B) at least one polyisocyanate group-containing compound having free or blocked isocyanate groups

and

(D) at least one catalyst based on a zinc-amidine complex which is prepared by reacting one or more zinc(II) biscarboxylates with an amidine of the formula (I) or with a mixture of two or more amidines of the formula (I)

wherein R 5 is hydrogen and R 1 , R 2 , R 3 , and R 4 are each identical or different radicals, with R 1 and R 3 being hydrogen or an alkyl radical or an aryl radical, and R 2 and R 4 being an alkyl radical or an aryl radical,

wherein

component (B) has at least one structural unit of the formula (II)

—NR—(X—SiR″ x (OR′)3- x )  (II),

and/or at least one structural unit of the formula (III),

—N(X—SiR″ x (OR′)3- x ) n (X′—SiR″ y (OR′)3- y ) m   (III),

wherein

R is alkyl, cycloalkyl, aryl or aralkyl, it being possible for the carbon chain to be interrupted by nonadjacent oxygen, sulfur or NRa groups, wherein Ra is alkyl, cycloalkyl, aryl or aralkyl,

R′ is hydrogen, alkyl or cycloalkyl, it being possible for the carbon chain to be interrupted by nonadjacent oxygen, sulfur or NRa groups, wherein Ra is alkyl, cycloalkyl, aryl or aralkyl,

X, X′ are linear and/or branched alkylene or cycloalkylene radicals having 1 to 20 carbon atoms,

R″ is alkyl, cycloalkyl, aryl, or aralkyl, it being possible for the carbon chain to be interrupted by nonadjacent oxygen, sulfur or NRa groups, wherein Ra is alkyl, cycloalkyl, aryl or aralkyl,

n is 0 to 2, m is 0 to 2, m+n is 2, and x, y are 0 to 2,

and wherein the coating material composition comprises

(S) at least one monomeric aromatic optionally substituted carboxylic acid comprising a carboxyl group in conjugation with a π-electron system.

2. The coating material composition of claim 1 , wherein the radicals R 2 and R 4 are identical or different acyclic, straight-chain or branched alkyl radicals and/or identical or different aryl radicals, and the radicals R 1 and R 3 are hydrogen or identical or different acyclic, straight-chain or branched alkyl radicals and/or identical or different aryl radicals.

3. The coating material composition of claim 1 , wherein the zinc-amidine complex is prepared by reacting 1.0 mole of one or more zinc(II) biscarboxylates with at least 0.1 mole of one or more amidines of the formula (I).

4. The coating material composition of claim 1 , wherein the carboxylate radical of the zinc-amidine complex (D) is selected from the group of carboxylate radicals of aliphatic linear and/or branched, optionally substituted monocarboxylic acids having 1 to 12 C atoms in the alkyl radical and/or of aromatic, optionally substituted monocarboxylic acids having 6 to 12 C atoms in the aryl radical.

5. The coating material composition of claim 1 , wherein the coating material composition comprises at least one zinc-amidine complex (D) in an amount such that the metal content of the zinc-amidine complex, based in each case on the binder fraction of the coating material composition, is between 35 and 2000 ppm, and/or the coating material composition comprises 0.2% to 15.0% by weight of at least one aromatic carboxylic acid (S), the percentages by weight in turn being based in each case on the binder fraction of the coating material composition.

6. The coating material composition of claim 1 , wherein between 10 and 90 mol % of the isocyanate groups originally present in component (B) were converted into structural units (II) and/or (III).

7. The coating material composition according of claim 1 , wherein the total amount of structural units (II) in component (B) is between 5 and 70 mol %, based in each case on the entirety of the structural units (II) plus (III), and the total amount of structural units (III) in component (B) is between 95 and 30 mol %, based in each case on the entirety of the structural units (II) plus (III).

8. The coating material composition of claim 1 , wherein component (B) comprises a polyisocyanate parent structure selected from 1,6-hexamethylene diisocyanate, isophorone diisocyanate, 4,4′-methylenedicyclohexyl diisocyanate, or the isocyanurate trimer thereof, or the allophanate dimer thereof, or the biuret dimer thereof, or the uretdione dimer thereof.

9. The coating material composition of claim 8 , wherein component (B) is prepared by reacting the polyisocyanates or the isocyanate trimers thereof or the allophanate dimers thereof or the biuret dimers thereof or the uretdione dimers thereof with at least one compound of the formula (IIa)

H—NR—(X—SiR″ x (OR′)3- x )  (IIa)

or with at least one compound of the formula (IIIa)

HN(X—SiR″ x (OR′)3- x ) n (X′—SiR″ y (OR′)3- y ) m   (IIIa),

wherein

R is alkyl, cycloalkyl, aryl or aralkyl, it being possible for the carbon chain to be interrupted by nonadjacent oxygen, sulfur or NRa groups, wherein Ra is alkyl, cycloalkyl, aryl or aralkyl,

R′ is hydrogen, alkyl or cycloalkyl, it being possible for the carbon chain to be interrupted by nonadjacent oxygen, sulfur or NRa groups, wherein Ra is alkyl, cycloalkyl, aryl or aralkyl,

X, X′ are linear and/or branched alkylene or cycloalkylene radicals having 1 to 20 carbon atoms,

R″ is alkyl, cycloalkyl, aryl, or aralkyl, it being possible for the carbon chain to be interrupted by nonadjacent oxygen, sulfur or NRa groups, wherein Ra is alkyl, cycloalkyl, aryl or aralkyl,

n is 0 to 2, m is 0 to 2, m+n is 2, and x, y are 0 to 2.

10. The coating material composition of claim 1 , wherein, in component (B), the total amount of structural units (II) is between 9 and 40 mol % and the total amount of structural units (III) is between 91 and 60 mol %, based in each case on the entirety of the structural units (II) plus (III),

and

between 31 and 50 mol % of the isocyanate groups originally present in component (B) are converted into structural units (II) and (III),

and,

in component (B), between 26 and 35 mol % of the isocyanate groups originally present are converted into structural units (III).

11. The coating material composition of claim 1 , wherein the coating material composition comprises from 20% to 80% by weight based in each case on the binder fraction of the coating material, of at least one hydroxyl-containing polyacrylate (A) and/or at least one hydroxyl-containing polymethacrylate (A), and the coating material composition comprises from 5% to 79% by weight, based in each case on the binder content of the coating material composition, of the compound (B) containing polyisocyanate groups.

12. A multistage coating method the method comprising applying to an optionally precoated substrate a pigmented basecoat film, followed by applying a film of the coating material composition of claim 1 .

13. The multistage coating method of claim 12 , wherein application of the pigmented basecoat film is followed first by drying of the applied pigmented basecoat material at temperatures from room temperature to 80° C., and the application of the coating material composition is followed by curing at temperatures between 20 and 80° C.

14. A multicoat color and/or effect paint system comprising at least one pigmented basecoat film and at least one clearcoat film disposed thereon, wherein the clearcoat film is produced from the coating material composition of claim 1 .