Pearlescent pigments having a secondary coating comprising α-silanes and method for the production thereof

US8197591B2 · kind B2 · utility

Assignee

• ECKART GmbH · DE

Inventors

• Günter Kaupp · Jessenitz Siedlung, DE
• Ulrich Schmidt · Flörsheim, DE

Key dates

• Filing date: Feb 23, 2007
• Grant date: Jun 12, 2012
• Expiry date: Jul 21, 2029

Classification

• Technology area (CPC Y): Emerging Cross-Sectional Technologies
• CPC primary: Y10T428/2996
• WIPO field: Basic materials chemistry
• WIPO sector: Chemistry

Abstract

The invention relates to a pearlescent pigment comprising a metal oxide-containing, platelet-shaped substrate and having a first and a second protective layer, wherein the metal oxide has a refractive index greater than 1.8, and in which the first protective layer comprises cerium oxide and/or hydrated cerium oxide and/or cerium hydroxide, the second protective layer consists substantially, preferably completely, of SiO2, wherein the second protective layer is disposed on top of the first protective layer, and between the first and second protective layers there can be disposed metal oxide layers which differ from cerium oxide and/or hydrated cerium oxide and/or cerium hydroxide and SiO2, wherein the second protective layer has an organochemical aftercoat and the organochemical aftercoat comprises at least one silane bonded to the second protective layer by means of at least one oxygen atom, said α-silane having the formula—O(4-n-m)—Si(—R1)m(—CH2—Y)n  (I),in which 1≦n+m≦3; m=0 to 2; n=1 to 3 and