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:
Mar. 31, 1992
Filed:
Mar. 20, 1990
Applicant:
Inventors:
Assignee:
Nissan Chemical Industries Ltd., Tokyo, JP;
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
B01J / ; C01B / ;
U.S. Cl.
CPC ...
2523132 ; 51308 ; 10628734 ;
Abstract
A high-purity stable aqueous silica sol is prepared which has an SiO.sub.2 concentration of from 30 to 50% by weight and which is substantially free from any other polyvalent metal oxides than silica and in which the colloidal silica has a mean particle size falling within the range of from 10 to 30 millimicrons. The silica sol obtained by the method of the present invention has an extremely low content of oxides of polyvalent metals such as iron or aluminum and may therefore be employed for uses which require the absence of such metals in the silica sol, for example, as an abrasive for semiconductors.