Coated titanium dioxide pigments and processes for production and use
US6342099B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Sep 15, 2000 |
| Grant date | Jan 29, 2002 |
| Priority date | — |
| Expiry date | Sep 15, 2020 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T428/2991
- WIPO fieldBasic materials chemistry
- WIPO sectorChemistry
Abstract
The present invention provides a coated titanium dioxide pigment which includes a base titanium dioxide pigment; a first deposit of a phosphate compound contiguous with the base titanium dioxide pigment; a deposit of a silica or zirconia compound contiguous with the phosphate deposit; a second deposit of a phosphate compound contiguous with the silica or zirconia compound; and a deposit of an alumina compound contiguous with the second phosphate deposit. Titanium dioxide pigments of the present invention are easily dispersible, and display excellent durability and gloss. The present invention also provides processes for preparing coated titanium dioxide pigments which include the steps of: preparing an aqueous slurry of base titanium dioxide pigment, adding a first phosphate compound to the slurry to form a first phosphate coating, adding a silica or zirconia compound to the slurry to form a silica compound coating, adding a second phosphate compound to the slurry, and adding an alumina compound coating to the slurry to form an alumina compound coating, thereby forming the coated titanium dioxide pigment.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.