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. 24, 2007
Filed:
Nov. 01, 2005
Russell Bertrum Diemer, Jr., Wilmington, DE (US);
Alan Roger Eaton, Hendersonville, TN (US);
Narayanan Sankara Subramanian, Hockessin, DE (US);
Stephen William Taylor, Chadds Ford, PA (US);
George A. Schurr, Newark, DE (US);
David a Zimmerman, Wilmington, DE (US);
Russell Bertrum Diemer, Jr., Wilmington, DE (US);
Alan Roger Eaton, Hendersonville, TN (US);
Narayanan Sankara Subramanian, Hockessin, DE (US);
Stephen William Taylor, Chadds Ford, PA (US);
George A. Schurr, Newark, DE (US);
David A Zimmerman, Wilmington, DE (US);
E. I. du Pont de Nemours and Company, Wilmington, DE (US);
Abstract
This disclosure relates to process for producing titanium dioxide (TiO) pigments, comprising the following steps: a) oxidizing a mixture of titanium tetrahalide and a rutile forming agent, such as aluminum halide, present in the vapor phase and in the presence of a nucleant to form a gaseous suspension comprising titanium dioxide particles; b) passing the gaseous suspension to a cooling conduit; c) introducing scouring material into the cooling conduit; wherein the particles of the scouring material have a diameter in the range of about 0.25 mm to about 12.7 mm; d) separating the vapor phase to form a powder comprising the titanium dioxide particles and the scouring material; and e) simultaneously subjecting the powder to substantially uniform heating at a temperature of about 300° C. to about 600° C. and reducing the size of the titanium dioxide particles and the particles of the scouring material in the powder to a mean particle size of about 50 nm to about 1000 nm, whereby the titanium dioxide pigment has a chloride content of less than about 500 ppm. The so treated powder may have a residual free chlorine content of less than about 1 ppm.