Stable colloidal silica, and, processes for preparing a colloidal silica, for preparing a cellulosic sheet, and for increasing the drainage of a papermaking mass in a papermaking machine

摘要

"STABLE COLOIDAL SILICA, AND, PROCESSES FOR PREPARING A COLLOIDAL SILICA, FOR PREPARING A CELLULOSIC SHEET, AND FOR INCREASING THE DRAINAGE OF A PAPER MANUFACTURING MASS IN A PAPER MANUFACTURING MACHINE". Colloidal, aqueous, stable silicas are described, having a surface area greater than 700 m ^ 2 ^ / g and S values of 20-50. These colloidal silicas do not require treatment with a surface treatment agent such as aluminum to achieve stability. These colloidal silica aquasols can be produced and stored in concentrations greater than 7 weight percent of SiO ~ 2 ~ solids, and even as high as 15 weight percent or greater, and remain stable at room temperature for at least least 30 days. These colloidal silica sols are useful as drainage and retention agents in papermaking processes. Also described are processes for preparing aqueous colloidal silica of the invention and papermaking processes employing colloidal silica sols.