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:
Oct. 18, 1983
Filed:
Apr. 10, 1981
Horacio E Bergna, Wilmington, DE (US);
E. I. Du Pont de Nemours and Co., Wilmington, DE (US);
Abstract
Concentrated aqueous silica sols of small silica particles about 10 nm or less in diameter and uniformly sized are prepared by a process for maintaining a constant number of silica nuclei particles prior to the deposition process. The process for maintaining a constant number of silica nuclei particles in the sol consists of forming the particles at a pH 8-10.5 and a low temperature then heating the sol through a transition temperature to a deposition temperature, maintaining the pH, removing alkali metal ions and simultaneously adding alkali metal silicate from the system at a rate such that the number of silica particles in the sol remains constant while the temperature is being raised.