Method for producing silica sol

Abstract

Provided is a method for producing a silica sol. A gel-like material cannot be generated and highly associated silica particles can be obtained. A method for producing a silica sol, comprising a step of making a reaction liquid by mixing liquid (A) comprising an alkaline catalyst, water, a first organic solvent and silica particles for association with liquid (B) comprising at least one of tetramethoxysilane and a condensate thereof and a second organic solvent, wherein during the mixing, an addition rate of the liquid (B) is 8.5×10 −4 to 5.6×10 −3 mol/min in terms of silicon atoms with respect to 1 mol of the water contained in the liquid (A).

1 . A method for producing a silica sol, comprising making a reaction liquid by mixing a liquid (A) comprising an alkaline catalyst, water, a first organic solvent and silica particles for association with a liquid (B) comprising at least one of tetramethoxysilane and a condensate thereof and a second organic solvent, wherein during the mixing, an addition rate of the liquid (B) is 8.5×10 −4  to 5.6×10 −3  mol/min in terms of silicon atoms with respect to 1 mol of the water contained in the liquid (A). 
     
     
         2 . The production method according to  claim 1 , wherein a molar ratio of the alkaline catalyst to the water in the liquid (A) is 0.01 to 0.30. 
     
     
         3 . The production method according to  claim 1 , wherein the alkaline catalyst is ammonia. 
     
     
         4 . The production method according to  claim 1 , wherein the liquid (A) consists of the alkaline catalyst, the water, the first organic solvent and the silica particles for association. 
     
     
         5 . The production method according to  claim 1 , wherein the liquid (B) consists of the at least one of tetramethoxysilane and a condensate thereof and the second organic solvent. 
     
     
         6 . The production method according to  claim 1 , wherein the first organic solvent and the second organic solvent are methanol. 
     
     
         7 . The production method according to  claim 1 , wherein a temperature of the reaction liquid is 5 to 100° C. 
     
     
         8 . The production method according to  claim 1 , wherein a temperature of the reaction liquid is 5 to 70° C.