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:
Nov. 30, 1999
Filed:
Oct. 17, 1997
Richard W Brotzman, Jr, Naperville, IL (US);
John H Aikens, LaGrange Park, IL (US);
Nanophase Technologies Corporation, Burr Ridge, IL (US);
Abstract
A coated ceramic powder comprises a plurality of ceramic particles and a siloxane star-graft coating polymer encapsulating at least a portion of the particles. The coating polymer comprises Si(w,x,y,z), where w, x, y and z are the mole percent tetrafunctional, trifunctional, difunctional and monofunctional monomeric units, respectively, and wherein w, x, y and z are about 45-75, 5-25, 5-45 and 5-10, respectively. A method of preparing a coated ceramic powder comprises the steps of (a) polymerizing each of a tetrafunctional siloxane monomer, a trifunctional siloxane monomer, a difunctional siloxane monomer, and a monofunctional siloxane monomer, (b) adding a quantity of ceramic powder to a reaction vessel, (c) shear mixing the ceramic powder for a time sufficient to wet substantially all of the powder surface, (d) adding the siloxane polymer prepared in step (a) to the reaction vessel containing the shear mixed ceramic powder, (e) shear mixing the shear mixed ceramic powder and the siloxane polymer for a time sufficient to form a siloxane polymer coated ceramic powder, and (f) separating the coated ceramic powder from the components remaining in the reaction vessel. The process may be rendered continuous by employing continuous high-shear mixing equipment and appropriate process modifications.