Silica sol having low turbidity and low viscosity

Abstract

Abstract PURPOSE:To obtain a silica sol having excellent transparency and low viscosity, by using a silica sol having specific turbidity and viscosity as a component. CONSTITUTION:The objective silica sol has a turbidity of formula I and a viscosity of formula II wherein tau is turbidity (1/cm) of silica sol at a SiO2 concentration 3wt%; eta is viscosity (cp) of silica sol having a SiO2 concentration of 30wt% at 25 deg.C; D is average particle diameter (mu) of silica particles in the silica sol. The silica sol can be produced e.g. by the following process. (A) An acidic silicic acid is mixed with an aqueous solution of alkali silicate and/or an alkaline aqueous solution. (B) The molar ratio SiO2/M2O (M is alkali metal) of the mixture is adjusted to 2.8-10 and the mixture is aged at >=60 deg.C to obtain a seed liquid. (C) An acidic silicic acid solution is added to the seed liquid at a rate slower than the rate defined by formula III while keeping the seed liquid at >=60 deg.C to effect the building up to silica on the seed. The silica sol produced by the above process contains silica particles having uniform particle diameter of 5-30mu and dispersed in a dispersion medium.

Inventors

• 👤 Goro Sato
• 👤 護郎 佐藤
• 👤 Yusaku Arima
• 👤 悠策 有馬
• 👤 Hiroyasu Nishida
• 👤 広泰 西田

Bibliographic Details