The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jul. 13, 1999
Filed:
Dec. 23, 1997
Narayanan Sankara Subramanian, Hockessin, DE (US);
Pratibha Laxman Gai, Wilmington, DE (US);
Russell Bertrum Diemer, Jr, Wilmington, DE (US);
Alvin Allen, Claymont, DE (US);
John Steven Gergely, Avondale, PA (US);
E. I. du Pont de Nemours and Company, Wilmington, DE (US);
Abstract
The present invention provides a process for producing titanium dioxide (TiO.sub.2) pigment having a coating comprising silica and a second oxide selected from the group consisting of oxides of boron, phosphorus, magnesium, niobium, germanium, and mixtures thereof, comprising the steps of (a) reacting titanium tetrachloride (TiCl.sub.4) in the vapor phase with an aluminum compound and an oxygen-containing gas in a reactor at a temperature in the range of about 900.degree. C. to about 1600.degree. C. to provide a gaseous suspension comprising TiO.sub.2 particles, (b) contacting the gaseous suspension comprising the TiO.sub.2 particles with a silicon halide and an oxide precursor of boron, phosphorus, magnesium, niobium, germanium, and mixtures thereof, and (c) cooling the gaseous suspension to produce TiO.sub.2 pigment having a coating comprising silica and a second oxide.