Zinc-magnesium anticorrosion pigments, anticorrosion paint, and method for the production of said anticorrosion pigments

• US 9,718,965 B2
• Filed: 08/20/2013
• Issued: 08/01/2017
• Est. Priority Date: 08/20/2012
• Status: Active Grant

• Current Assignee: Eckart GmbH (Eckart)
• Original Assignee: Eckart GmbH (Eckart)
• Inventors: Pfammatter, Dominik, Hubner, Sandra, Constantin, Laurent, Hafner, Horst, Rupprecht, Markus, Wolfrum, Christian, Decelles, Guy, Voit, Thomas
• Primary Examiner(s): Sheikh, Humera
• Assistant Examiner(s): Wang, Lucas
• Application Number:
  US14/422,441
• Publication Number:
  US 20150218388A1
• Time in Patent Office: 1,442 Days
• CPC Class Codes: B22F 1/068 Flake-like particles
• CPC Class Codes: B22F 2009/043 by ball milling
• CPC Class Codes: B22F 2998/10 Processes characterised by the sequence of their steps
• CPC Class Codes: B22F 9/04 starting from solid material, e.g. by crushing, grinding or milling C22C1/1084 takes precedence; crushing, grinding or milling, in general, see the relevant subclasses, e.g. B02C
• CPC Class Codes: B22F 9/082 atomising using a fluid using centrifugal force B22F9/10
• CPC Class Codes: C01P 2004/03 obtained by SEM
• CPC Class Codes: C01P 2004/20 extending in two dimensions, e.g. plate-like
• CPC Class Codes: C01P 2004/22 with a polygonal circumferential shape
• CPC Class Codes: C01P 2004/51 Particles with a specific particle size distribution
• CPC Class Codes: C01P 2004/54 Particles characterised by their aspect ratio, i.e. the ratio of sizes in the longest to the shortest dimension
• CPC Class Codes: C08K 2003/0893 Zinc
• CPC Class Codes: C08K 3/013 Fillers, pigments or reinforcing additives
• CPC Class Codes: C09C 1/62 Metallic pigments or fillers C09C1/0015 takes precedence
• CPC Class Codes: C09D 5/084 Inorganic compounds
• CPC Class Codes: C09D 5/10 containing metal dust
• CPC Class Codes: C09D 5/106 containing Zn
• CPC Class Codes: C09D 7/61 inorganic
• CPC Class Codes: C09D 7/70 characterised by shape, e.g. fibres, flakes or microspheres
• CPC Class Codes: C22C 1/0408 Light metal alloys
• CPC Class Codes: C22C 1/0483 Alloys based on the low melting point metals Zn, Pb, Sn, Cd, In or Ga
• CPC Class Codes: C22C 18/00 : Alloys based on zinc
• CPC Class Codes: C23C 30/005 : on hard metal substrates
• CPC Class Codes: Y10T 428/12736 : Al-base component

Abstract

The present invention relates to platelet-shaped zinc-magnesium pigments, wherein the platelet-shaped zinc-magnesium pigments comprise the 40.8 to 67.8 mol % of zinc, 32.2 to 59.2 mol % of magnesium and 0 to 7 mol % of Mn, Li, Be, Y, Sn, Al, Ti, Fe, Cu and mixtures thereof, based in each case on the total molar amount of the elements Zn, Mg, Mn, Be, Y, Li, Sn, Al, Ti, Fe and Cu, where the molar percentages add up to 100 mol %, and the median thickness h₅₀ of the pigments is less than 1 μm. The invention further relates to the use and production of these pigments.

Claims

1. A platelet-shaped zinc-magnesium pigment, comprising 40.8 to 67.8 mol % of zinc, 32.2 to 59.2 mol % of magnesium and 0 to 7 mol % of at least one metal selected from the group consisting of Mn, Li, Be, Y, Sn, Al, Ti, Fe, Cu and mixtures thereof, based upon the total molar amount of Zn, Mg, Mn, Be, Y, Li, Sn, Al, Ti, Fe and Cu, wherein the molar percentages add up to 100 mol %, and the median thickness h₅₀ of the pigments is less than 1 μ

m.

2. The platelet-shaped zinc-magnesium pigment according to claim 1, wherein the platelet-shaped zinc-magnesium pigment comprises 45.6 to 57.8 mol % of Zn, 42.2 to 54.4 mol % of Mg and 0 to 7 mol % of at least one metal selected from the group consisting of Mn, Li, Be, Y, Sn, Al, Ti, Fe, Cu and mixtures thereof, based upon the total molar amount of Zn, Mg, Mn, Be, Y, Li, Sn, Al, Ti, Fe and Cu, wherein the molar percentages add up to 100 mol % and where Zn, Mg, Mn, Be, Y, Li, Sn, Al, Ti, Fe and Cu constitute at least 93% by weight of the zinc-magnesium pigment based upon the total weight thereof.

3. The platelet-shaped zinc-magnesium pigment according to claim 1, wherein the platelet-shaped zinc-magnesium pigment comprises less than 0.15 mol % of at least one metal selected from the group consisting of Mn, Li, Be, Y, Sn and mixtures thereof, based upon the total molar amount of Zn, Mg, Mn, Be, Y, Li, Sn, Al, Ti, Fe and Cu.

4. The platelet-shaped zinc-magnesium pigment according to claim 1, wherein the platelet-shaped zinc-magnesium pigment has a median thickness from a range from 90 nm to less than 700 nm.

5. The platelet-shaped zinc-magnesium pigment according to claim 1, wherein the platelet-shaped zinc-magnesium pigment has a median diameter D₅₀ from a range from 3 to 25 μ

m.

6. The platelet-shaped zinc-magnesium pigment according to claim 1, wherein the platelet-shaped zinc-magnesium pigment has an aspect ratio within a range from 10 to 200.

7. The platelet-shaped zinc-magnesium pigment according to claim 1, wherein the platelet-shaped zinc-magnesium pigment has an aspect ratio within a range from 15 to 75.

8. A plurality of platelet-shaped zinc-magnesium pigments according to claim 1, wherein the platelet-shaped zinc-magnesium pigments have a size distribution having a span Δ

D according to formula (II)

SpanΔ

D=(D₉₀−

D₁₀)/D₅₀ 

 

(II)

of 1.0 to 2.3.

9. The platelet-shaped zinc-magnesium pigment according to claim 1, wherein the zinc-magnesium pigments comprise 47.3 to 54.2 mol % of Zn, 45.8 to 53.7 mol % of Mg and 0 to 4.6 mol % of at least one metal selected from the group consisting of Mn, Li, Be, Y, Sn, Al, Ti, Fe, Cu and mixtures thereof,

based upon the total molar amount of Zn, Mg, Mn, Be, Y, Li, Sn, Al, Ti, Fe and Cu,

wherein the molar percentages add up to 100 mol %,

the median thickness h₅₀ of the pigment is less than 700 nm, and

where Zn, Mg, Mn, Be, Y, Li, Sn, , Ti, Fe and Cu constitute at least 93% by weight of the zinc-magnesium pigment, based on the total weight thereof.

10. The platelet-shaped zinc-magnesium pigment according to claim 1, wherein the platelet-shaped zinc-magnesium pigment has been obtained by mechanical forming by means of stirred ball mills as grinding unit.

11. An anticorrosion coating, wherein the anticorrosion coating comprises the platelet-shaped zinc-magnesium pigment of claim 1.

12. A coating for aircraft or coil coating, comprising the platelet-shaped zinc-magnesium pigment according to claim 1.

13. An article comprising the zinc-magnesium pigment of claim 1.

14. The article according to claim 13, wherein the article is selected from the group consisting of aircraft, ships, boats, motor vehicle bodies, buildings, facades, door and window frames, bridges, power masts and wind turbines.

15. The article according to claim 13, wherein the article comprises aluminium or an aluminium alloy.

16. A process for producing platelet-shaped anticorrosion pigments according to claim 1, wherein the process comprises:

mechanical forming of non-platelet-shaped zinc-magnesium pigments comprising 40.8 to 67.8 mol % of Zn, 32.2 to 59.2 mol % of Mg and 0 to 7 mol % of at least one metal selected from the group consisting of Mn, Li, Be, Y, Sn, Al, Ti, Fe, Cu and mixtures thereof, based upon the total molar amount of Zn, Mg, Mn, Be, Y, Li, Sn, Al, Ti, Fe and Cu, wherein the molar percentages add up to 100 mol %, and

wherein an energy input of at least 2500 kJ per kg of platelet-shaped zinc-magnesium particles is effected at a rate of at least 600 kJ per kg of platelet-shaped zinc-magnesium particles per hour.

17. A process for protecting an article comprising aluminium or an aluminium alloy from corrosion, comprising coating the article with a coating comprising zinc-magnesium pigments according to claim 1.

18. An article comprising an anticorrosion coating of claim 11.

19. The article according to claim 13, wherein the article body consists of aluminium or an aluminium alloy.