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. 27, 1993
Filed:
Aug. 19, 1992
John A Romberger, Oak Park, IL (US);
Charles C Payne, Aurora, IL (US);
Nalco Chemical Company, Naperville, IL (US);
Abstract
A colloidal silica slurry comprising: a low metals ammonium-stabilized silica sol having the following characteristics: SiO.sub.2 present in the range between about 15 to about 50 weight percent; a pH in the range between about 8.5 to about 11.3; a particle diameter in the range between about 4.0 to about 130 nm; aluminum, as Al, present in an amount less than about 100 ppm, based on SiO.sub.2 ; iron, as Fe, present in an amount less than about 50 ppm, based on SiO.sub.2 ; potassium, as K, present in an amount less than about 25 ppm, based on SiO.sub.2 ; and sodium, as Na, present in an amount less than about 500 ppm, based on SiO.sub.2 ; and a bactericide, a polishing rate accelerator which differs from the bactericide, and/or a sodium chlorite or sodium hypochlorite biocide. Optionally, a fungicide may also be added to the colloidal silica slurry to inhibit fungi growth.