Multilayer interference pigments

US6284032A · kind A · 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: Jan 11, 2001
• Grant date: Sep 4, 2001
• Expiry date: Jan 11, 2021

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C09C2220/20
• WIPO field: Basic materials chemistry
• 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 hydrolysable 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.