Ceramic pigments

• US 8,029,615 B2
• Filed: 10/30/2007
• Issued: 10/04/2011
• Est. Priority Date: 10/31/2006
• Status: Active Grant

• Current Assignee: Charles Watkinson
• Original Assignee: Charles Watkinson
• Inventors: Watkinson, Charles
• Primary Examiner(s): GREEN, ANTHONY J
• Application Number:
  US12/513,152
• Publication Number:
  US 20100064941A1
• Time in Patent Office: 1,435 Days
• Field of Search: 106/415, 106/436, 106/438, 106/439, 106/450, 106/453, 106/456, 106/459
• US Class Current: 106/415
• CPC Class Codes: C01P 2004/20 extending in two dimensions, e.g. plate-like
• CPC Class Codes: C01P 2004/61 Micrometer sized, i.e. from 1-100 micrometer
• CPC Class Codes: C09C 1/0021 comprising a core coated with only one layer having a high or low refractive index
• CPC Class Codes: C09C 2200/102 the core consisting of glass or silicate material like mica or clays, e.g. kaolin
• CPC Class Codes: C09C 2200/301 Thickness of the core

Abstract

A pearlescent pigment includes a ceramic flake coated with a metal oxide. The metal oxide is, preferably, an oxide of titanium, iron, tin, chromium1, zirconium or a combination thereof, and the refractive index of the metal oxide coating is preferably at least 0.5 higher than that of the ceramic flake. The pearlescent pigment may be included in a coating applied to a metallic or plastic surface to give the surface a lustrous or pearlescent optical effect.

Claims

1. A pearlescent pigment, comprising:

ceramic flakes having a single coating comprising a metal oxide, said coating having a refractive index that is at least 0.5 higher than that of said ceramic flakes, wherein said ceramic flakes has a composition that includes;

50-70 wt % SiO₂;

15-25 wt % CaO;

10-20 wt % MgO; and

0-1 wt % ZrO₂.

2. The pearlescent pigment according to claim 1, wherein the metal oxide is an oxide of a metal selected from the group consisting of titanium, iron, tin, chromium, zirconium and a combination thereof.

3. The pearlescent pigment according to claim 1, wherein said ceramic flakes have a thickness of from 100 nm to 10 μ

m.

4. The pearlescent pigment according to claim 1, wherein said ceramic flakes have a size of from 10 μ

m to 100 μ

m.

5. The pearlescent pigment according to claim 1, wherein said coating that includes the metal oxide has a refractive index that is at least 1.0 higher than that of said ceramic flakes.

6. The pearlescent pigment according to claim 1, wherein said ceramic flakes have a composition of:

65 wt % SiO₂;

19.5 wt % CaO;

15 wt % MgO; and

0.5 wt % ZrO₂.

7. The pearlescent pigment according to claim 1, wherein said coating that includes the metal oxide has a refractive index that is at least 1.5 higher than that of said ceramic flakes.

8. A method for providing a lustrous or pearlescent optical effect to a metallic surface or a plastic surface, comprising the step of:

coating a metal surface or a plastic surface with a pigment having ceramic flakes that include a single coating comprising a metal oxide, said coating having a refractive index that is at least 0.5 higher than that of said ceramic flakes, wherein said ceramic flakes has a composition that includes;

50-70 wt % SiO₂;

15-25 wt % CaO;

10-20 wt % MgO; and

0-1 wt % ZrO₂.

9. The method for providing a lustrous or pearlescent optical effect to a metallic surface or a plastic surface according to claim 8, wherein the metal oxide is an oxide of a metal selected from the group consisting of titanium, iron, tin, chromium, zirconium and a combination thereof.

10. The method for providing a lustrous or pearlescent optical effect to a metallic surface or a plastic surface according to claim 8, wherein said ceramic flakes have a thickness of from 100 nm to 10 μ

m.

11. The method for providing a lustrous or pearlescent optical effect to a metallic surface or a plastic surface according to claim 8, wherein said ceramic flakes have a size of from 10 μ

m to 100 μ

m.

12. The method for providing a lustrous or pearlescent optical effect to a metallic surface or a plastic surface according to claim 8, wherein said coating that includes the metal oxide has a refractive index that is at least 1.0 higher than that of said ceramic flakes.

13. The method for providing a lustrous or pearlescent optical effect to a metallic surface or a plastic surface according to claim 8, wherein said ceramic flakes have a composition of:

65 wt % SiO₂;

19.5 wt % CaO;

15 wt % MgO; and

0.5 wt % ZrO₂.

14. The method for providing a lustrous or pearlescent optical effect to a metallic surface or a plastic surface according to claim 8, wherein said coating that includes the metal oxide has a refractive index that is at least 1.5 higher than that of said ceramic flakes.