STABLE SILICA SOLS OF HIGH SURFACE AREA AND IMPROVED ACTIVITY

摘要

Disclosed are stable, aqueous colloidal silicas having surface area of great er than 700m2/g and S-values of from 20-50. These colloidal silicas do not require treatment with a surface treating agent such as aluminium to achieve stability. These colloidal silica aquasols can be produced and stored at concentrations greater than 7 percent by weight SiO2 solids, and even as hig h as 15 percent by weight solids or higher, and remain stable at room temperature for at least 30 days. These colloidal silica sols are useful as drainage and retention agents in papermaking processes. Also disclosed are processes for making aqueous colloidal silica o f the invention and papermaking processes employing the colloidal silica sols.