METHOD FOR PREPARING SILICA ORGANOSOL

摘要

PURPOSE: A method for preparing colloidal silica organosol having superior dispersibility, excellent stability and very low impurity content from aqueous colloidal silica sol using water as dispersion medium is provided. CONSTITUTION: The method comprises first process of removing ions from the aqueous silica sol by passing aqueous silica sol having average particle diameter of 5 to 300 nm and SiO2 concentration of 10 to 40 wt.% through ion exchange resin columns respectively filled with hydrogen type strongly acidic cation exchange resin and hydroxyl type strongly basic anion exchange resin for one or more times irrespective of sequence; second process of aging the pH adjusted acid added aqueous silica sol after adding acid to the aqueous silica sol ion exchanged in the first process and adjusting pH of the acid added aqueous silica sol to 0.5 to 2; third process of removing ions from the aqueous silica sol by secondly treating the aging treated aqueous silica sol in the same manner as in the first process; and fourth process of lowering water content of the aqueous silica sol to 1 wt.% or less by filtering and dehydrating a mixture of the aqueous silica sol and organic solvent using ultrafiltration method after mixing the aqueous silica sol from which ions are removed in the third process with an organic solvent.