Pigment preparation with metal effect pigments, method for the production of same and use of same

1. A pigment preparation comprising metal effect pigments, wherein

the metal effect pigments have an average size d 50 in a range of 1.7 to 2.8 μm and an average thickness h 50 in a range of 15 to 50 nm, as well as at least one polycarboxylic acid, wherein the at least one polycarboxylic acid has at least 4 carbon atoms.

2. The pigment preparation comprising metal effect pigments according to claim 1 , wherein

the metal effect pigments are produced by wet grinding.

3. The pigment preparation comprising metal effect pigments according to claim 1 , wherein

the metal effect pigments have an average thickness h 50 in the range of 20 to 40 nm.

4. The pigment preparation comprising metal effect pigments according to claim 1 , wherein

the metal effect pigments have an average size d 50 in the range of 1.9 to 2.8 μm.

5. The pigment preparation comprising metal effect pigments according to claim 1 , wherein

the metal effect pigments have an average size d 50 in the range of 2.1 to 2.8 μm.

6. The pigment preparation comprising metal effect pigments according to claim 1 , wherein

the metal effect pigment comprises at least one metal selected from the group consisting of aluminum, aluminum alloys, copper, copper alloys and brass and iron.

7. The pigment preparation comprising metal effect pigments according to claim 6 , wherein

the metal effect pigment consists of aluminum or aluminum alloy(s).

8. The pigment preparation comprising metal effect pigments according to claim 1 , wherein

the at least one polycarboxylic acid is covalently bonded to at least one polyglycol ether.

9. The pigment preparation comprising metal effect pigments according to claim 1 , wherein

the pigment preparation additionally comprises at least one dispersing additive structurally different from the polycarboxylic acid.

10. The pigment preparation comprising metal effect pigments according to claim 1 , wherein

the metal effect pigments have a cumulative frequency distribution with a d 50 value in a range of 2.1 to 2.8 μm and a d 90 value in a range of 4.0 to 8.0 μm.

11. The pigment preparation comprising metal effect pigments according to claim 1 , wherein

the level of metal effect pigments lies in a range of 10 to 90 wt.-%, relative to the total weight of the pigment preparation.

12. The pigment preparation comprising metal effect pigments according to claim 1 , wherein

the pigment preparation is present as a flexographic ink.

13. An ink comprising the pigment preparation according to claim 1 .

14. A flexographic ink comprising the pigment preparation according to claim 1 .

15. The flexographic ink according to claim 14 , wherein

the flexographic ink further comprises at least one solvent and has a viscosity of an efflux time at 25° C. in a DIN 4 beaker in the range of 15 to 40 s.

16. The flexographic ink according to claim 14 , wherein

the flexographic ink further comprises a mixture of ethyl cellulose and polyvinyl butyral as binder.

17. A method for producing a pigment preparation comprising:

grinding metal grit with a d 50,grit of 0.6 to 2.4 μm and a d 90 of 1.6 to 4.3 μm in the presence of at least one polycarboxylic acid, which has at least 4 carbon atoms, with grinding media, obtaining metal effect pigments having an average size d 50 in the range of 1.7 to 2.8 μm and an average thickness h 50 in the range of 15 to 50 nm.

18. The method of producing a pigment preparation according to claim 17 , wherein

the metal grit is ground in a stirred ball mill.

19. The method of producing a pigment preparation according to claim 17 , wherein

at least one dispersing additive structurally different from the polycarboxylic acid is additionally added.

20. A flexographic print prepared from the flexographic ink according to claim 14 .