Weather resistant titanium dioxide pigment and a process for its production
US7682441B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jun 21, 2005 |
| Grant date | Mar 23, 2010 |
| Priority date | — |
| Expiry date | Mar 1, 2026 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC08K9/02
- WIPO fieldMacromolecular chemistry, polymers
- WIPO sectorChemistry
Abstract
The invention relates to a weather resistant titanium dioxide pigment with good optical properties having a SiO2 dense skin doped with metal atoms. Particularly suitable elements for doping are tin, zirconium and titanium. The SiO2 dense skin is composed of multiple layers whereby the innermost layer does not contain any significant quantity of metal atoms. The coating according to the invention is produced by adding the components to the alkaline suspension (pH at least 9) one after the other with a sliding pH. Complete formation of the doped SiO2 dense skin requires that the pH subsequently be lowered to below 9. The pigment is particularly suitable for use in surface coatings and plastics.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.