Optically variable pigments having an asymmetrical layer structure
US7374609B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Nov 12, 2003 |
| Grant date | May 20, 2008 |
| Priority date | — |
| Expiry date | May 26, 2024 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC09C2220/20
- WIPO fieldBasic materials chemistry
- WIPO sectorChemistry
Abstract
The present invention relates to pigments whose particles have a length of from 2 μm to 5 mm, a width of from 2 μm to 2 mm and a thickness of from 50 nm to 1.5 μm and a ratio of length to thickness of at least 2:1, the particles having a core of a metallically reflecting material having two substantially parallel faces, the distance between which is the shortest axis of the core, comprising (a), optionally, on one parallel face of the core, an SiOy layer wherein 0.95<y≦2.0, (b), on the SiOy layer, an SiOx layer wherein 0.03<x≦0.95, and (c), on the SiOx layer, an SiOz layer wherein 0.95<z≦2.0, to a method for the production thereof, and to the use thereof in paints, textiles, ink-jet printing, cosmetics, coating compositions, plastics, printing inks and in glazes for ceramics and glass. The pigments without an SiOy layer produce brilliant colours. The pigments with an SiOy layer are opaque and exhibit brilliant colours with a metallic appearance.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.