Multi-coated interference pigments

US6500251B1 · kind B1 · utility

Assignee

• Merck Patent GmbH · DE

Inventors

• Stephanie Andes · Hanau, DE
• Gerd Bauer · Kleinostheim, DE
• Gunter Brenner · Griesheim, DE
• Dieter Bruckner · Darmstadt, DE
• Michael Schmelz · Griesheim, DE
• Andrea Heyland · Ober-Kainsbach, DE
• Matthias Kuntz · Seeheim-Jugenheim, DE
• Karl Osterried · Dieburg, DE
• Gerhard Pfaff · Mainburg, DE

Key dates

• Filing date: Mar 9, 1999
• Grant date: Dec 31, 2002
• Expiry date: Mar 9, 2019

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C09C2220/106
• WIPO field: Pharmaceuticals
• WIPO sector: Chemistry

Abstract

Multilayer interference pigment consisting of plateletlike titanium dioxide as carrier material, coated with alternating layers of metal oxides of low and high refractive index, the difference in the refractive indices being at least 0.1, which is obtainable by solidification and hydrolysis of an aqueous solution of a thermally hydrolyzable titanium compound on a continuous belt, detachment of the resulting coat, coating of the resulting titanium dioxide platelets, with or without drying in between, by a wet method with, alternately, a metal oxide hydrate of high refractive index and a metal oxide hydrate of low refractive index by hydrolysis of the corresponding, water-soluble metal compounds, separation, drying and, if desired, calcining of the material obtained.