Alpha-alumina flakes

Patent metadata

Field	Value
Publication number	US-11891541-B2
Application number	US-202217720607-A
Country	US
Kind code	B2
Filing date	Apr 14, 2022
Priority date	Apr 30, 2013
Publication date	Feb 6, 2024
Grant date	Feb 6, 2024

Abstract

Alpha-Alumina flakes having a particle thickness of 130-400 nm, a D 50 -value of 15-30 μm, a D 90 -value of 30-45 μm and a D 10 -value of <9.5 μm. Use of the alumina flakes in varnishes, paints, automotive coatings printing inks, masterbatches, plastics and cosmetic formulations. Also, use of the alumina flakes as a substrate for effect pigments and in organic dyes.

First claim

The invention claimed is:

1. An automobile coating, automotive finishing or industrial coating,
comprising
(1) coated and/or uncoated Al 2 O 3 flakes having a particle thickness of 130-400 nm, D 50 -value of 15-30 μm, D 90 -value of 30-45 μm and a D 10 -value of <9.5 λm, wherein the coated A 2 O 3 flakes have one or more coatings on top of and completely encapsulating said Al 2 O 3 flakes and forming one or more layers apart from the Al 2 O 3 flakes, wherein said Al 2 O 3 flakes are alpha-alumina flakes,
and
(2) one or more further ingredients apart from said coated and/or uncoated Al 2 O 3 flakes suitable for an automobile coating, automotive finishing or industrial coating.

2. The automobile coating, automotive finishing or industrial coating according to claim 1 , which is a single layer coating or a two-coat system in which the coated and/or uncoated Al 2 O 3 flakes are present in a base coat.

3. The automobile coating, automotive finishing or industrial coating according to claim 1 , wherein the coated and/or uncoated Al 2 O 3 flakes are present in an amount of 0.5 to 10% by weight based on the weight of the automobile coating, automotive finishing or industrial coating.

4. The automobile coating, automotive finishing or industrial coating according to claim 1 , wherein the Al 2 O 3 flakes have a particle thickness of 130-400 nm, D 50 -value of 15-30 μm, D 90 -value of 30-45 μm and a D 10 -value of 9.2 to 9.4 μm.

5. The automobile coating, automotive finishing or industrial coating according to claim 1 , wherein the Al 2 O 3 flakes are uncoated.

6. The automobile coating, automotive finishing or industrial coating according to claim 1 , wherein the Al 2 O 3 flakes have a standard deviation of thickness distribution of less than 80 nm.

7. The automobile coating, automotive finishing or industrial coating according to claim 1 , wherein the Al 2 O 3 flakes are doped with TiO 2 , ZrO 2 , SiO 2 , SnO 2 , In 2 O 3 , or ZnO or a combination thereof.

8. The automobile coating, automotive finishing or industrial coating according to claim 1 , wherein the Al 2 O 3 flakes are coated with at least one layer of a metal oxide, a mixture of at least two metal oxides, a metal, a metal sulphide, a titanium suboxide, a titanium oxynitride, FeO(OH), SiO 2 , a metal alloy or a rare earth compound, which form one or more coatings.

9. The automobile coating, automotive finishing or industrial coating according to claim 1 , wherein the Al 2 O 3 flakes are coated with at least one layer of a metal oxide or a mixture of at least two metal oxides.

10. The automobile coating, automotive finishing or industrial coating according to claim 1 , wherein the Al 2 O 3 flakes are coated with the following layer sequence:
Al 2 O 3 flake+TiO 2
Al 2 O 3 flake+TiO 2 /Fe 2 O 3
Al 2 O 3 flake+Fe 2 O 3
Al 2 O 3 flake+TiO 2 +Fe 2 O 3
Al 2 O 3 flake+TiO 2 +Fe 3 O 4
Al 2 O 3 flake+TiO 2 +SiO 2 +TiO 2
Al 2 O 3 flake+Fe 2 O 3 +SiO 2 +TiO 2
Al 2 O 3 flake+TiO 2 /Fe 2 O 3 +SiO 2 +TiO 2
Al 2 O 3 flake+TiO 2 +SiO 2 +TiO 2 /Fe 2 O 3
Al 2 O 3 flake+TiO 2 +SiO 2
Al 2 O 3 flake+TiO 2 +SiO 2 /Al 2 O 3
Al 2 O 3 flake+TiO 2 +Al 2 O 3
Al 2 O 3 flake+SnO 2
Al 2 O 3 flake+SnO 2 +TiO 2
Al 2 O 3 flake+SnO 2 +Fe 2 O 3
Al 2 O 3 flake+SiO 2
Al 2 O 3 flake+SiO 2 +TiO 2
Al 2 O 3 flake+SiO 2 +TiO 2 /Fe 2 O 3
Al 2 O 3 flake+SiO 2 +Fe 2 O 3
Al 2 O 3 flake+SiO 2 +TiO 2 +Fe 2 O 3
Al 2 O 3 flake+SiO 2 +TiO 2 +Fe 3 O 4
Al 2 O 3 flake+SiO 2 +TiO 2 +SiO 2 +TiO 2
Al 2 O 3 flake+SiO 2 +Fe 2 O 3 +SiO 2 +TiO 2
Al 2 O 3 flake+SiO 2 +TiO 2 /Fe 2 O 3 +SiO 2 +TiO 2
Al 2 O 3 flake+SiO 2 +TiO 2 +SiO 2 +TiO 2 /Fe 2 O 3
Al 2 O 3 flake+SiO 2 +TiO 2 +SiO 2
Al 2 O 3 flake+SiO 2 +TiO 2 +SiO 2 /Al 2 O 3
Al 2 O 3 flake+SiO 2 +TiO 2 +Al 2 O 3
Al 2 O 3 flake+TiO 2 +Prussian Blue or
Al 2 O 3 flake+TiO 2 +Carmine Red.

11. The automobile coating, automotive finishing or industrial coating according to claim 1 , wherein the Al 2 O 3 flakes are coated with TiO 2 in the rutile modification.

12. The automobile coating, automotive finishing or industrial coating according to claim 1 , wherein the Al 2 O 3 flakes are coated with TiO 2 in the anatase modification.

13. The automobile coating, automotive finishing or industrial coating according to claim 1 , wherein the Al 2 O 3 flakes are coated, and which coated flakes consist of 40-90 wt. % of Al 2 O 3 flakes and 10-60 wt. % of the one or more coatings.

14. The automobile coating, automotive finishing or industrial coating according to claim 1 , wherein the Al 2 O 3 flakes have a D 10 -value of <9.2μm.

15. The automobile coating, automotive finishing or industrial coating according to claim 1 , wherein the Al 2 O 3 flakes have a D 10 -value of 8.8 to 9.2 μm.

16. The automobile coating, automotive finishing or industrial coating according to claim 1 , wherein the Al 2 O 3 flakes have a particle thickness of 200-250 nm.

17. The automobile coating, automotive finishing or industrial coating according to claim 1 , wherein the Al 2 O 3 flakes have a particle thickness of 130-400 nm, D 50 -value of 15-30 μm, D 90 -value of 30-45 μm and a D 10 -value of 8.8 to <9.5 μm.

18. The automobile coating, automotive finishing or industrial coating according to claim 1 , wherein the coated and/or uncoated Al 2 O 3 flakes have a luster of 40-46, a haze-gloss of 21-25 and a Wa value of 9-12.

19. An automobile coating, automotive finishing or industrial coating composition, comprising
(1) coated and/or uncoated Al 2 O 3 flakes having a particle thickness of 130-400 nm, D 50 -value of 15-30 μm, D 90 -value of 30-45 μm and a D 10 -value of <9.5 μm, wherein the coated Al 2 O 3 flakes have one or more coatings on top of and completely encapsulating said Al 2 O 3 flakes and forming one or more layers apart from the Al 2 O 3 flakes, wherein said Al 2 O 3 are alpha-alumina flakes,
and
(2) one or more further ingredients apart from said coated and/or uncoated Al 2 O 3 flakes suitable for an automobile coating, automotive finishing or industrial coating.

20. The automobile coating, automotive finishing or industrial coating composition according to claim 17 , wherein the coated and/or uncoated Al 2 O 3 flakes are present in an amount of 0.5 to 10% by weight based on the weight of the automobile coating, automotive finishing or industrial coating.

21. A method for the laser marking of paper or a plastic or for the coloring of a tent awning, comprising applying to said paper, plastic or tent awning a coating composition, comprising
(1) coated and/or uncoated Al 2 O 3 flakes having a particle thickness of 130-400 nm, D 50 -value of 15-30 μm and a D 90 -value of 30-45 μm, D 10 -value of <9.5 μm, wherein the coated Al 2 O 3 flakes have one or more coatings on top of and completely encapsulating said Al 2 O 3 flakes and forming one or more layers apart from the Al 2 O 3 flakes, wherein said Al 2 O 3 flakes a alpha-alumnia flakes,
and
(2) one or more further distinct ingredients apart from said coated and/or uncoated Al 2 O 3 flakes suitable for an automobile coating, automotive finishing or industrial coating.

Assignees

• Merck Patent Gmbh

Inventors

• Suzuki Ryuta
• Pfaff Gerhard
• Schoen Sabine
• Matsuda Noriyuki
• Nitta Katsuhisa

Classifications

• C09D7/62 Primary

  modified by treatment with other compounds · CPC title

• C01F7/02

  Aluminium oxide; Aluminium hydroxide; Aluminates · CPC title

• C01F7/34

  Preparation of aluminium hydroxide by precipitation from solutions containing aluminium salts · CPC title

• C01F7/441

  by calcination · CPC title

• C09C1/0015

  Pigments exhibiting interference colours, e.g. transparent platelets of appropriate thinness or flaky substrates, e.g. mica, bearing appropriate thin transparent coatings · CPC title