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. 23, 1999
Filed:
Jun. 17, 1996
Mizusawa Industrial Chemical, Ltd., Tokyo, JP;
Abstract
A method of directly precipitating a spherical amorphous silica in a high yield by adding a carboxymethyl cellulose (CMC) as a coagulation growing agent in a step of neutralizing the alkali silicate with an acid. The CMC having a particular etherification degree and a particular polymerization degree is added in an amount of from 1 to 100% by weight reckoned as SiO.sub.2 with respect to silica in the alkali silicate, whereby the whole silica particles turn into spherical amorphous silica particles having high sphericalness. There can be obtained spherical amorphous silica particles having a BET specific surface area of from 25 to 800 m.sup.2 /g, an apparent specific gravity of from 0.1 to 0.8 and a particle diameter of from 0.2 to 50 .mu.m cheaply and in a high yield.