Silica particles and method of preparing the same

Abstract

Provided are silica particles having two maximum values in number particle size distribution, wherein in the two maximum values, a particle size ratio (a maximum value of a small-size side/a maximum value of a large-size side) between a maximum value of a large-size side and a maximum value of a small-size side is from 0.02 to 0.3, and a number ratio (a number of silica particles having a maximum value of the small-size side/number of silica particles having a maximum value of the large-size side) is from 1 to 100, and particles within a range of 10% from the large-size side of the silica particles have an average circularity of from 0.65 to 0.90 and an average shrinkage ratio of from 10 to 50.

What is claimed is: 
     
         1 . Silica particles having two maximum values in number particle size distribution,
 wherein in the two maximum values, a particle size ratio (a maximum value of a small-size side/a maximum value of a large-size side) is from 0.02 to 0.3, and a number ratio (a number of silica particles having a maximum value of the small-size side/number of silica particles having a maximum value of the large-size side) is from 1 to 100, and   particles within a range of 10% from the large-size side of the silica particles have an average circularity of from 0.65 to 0.90 and an average shrinkage ratio of from 10 to 50.   
     
     
         2 . The silica particles according to  claim 1 ,
 wherein the particle size ratio is from 0.03 to 0.2.   
     
     
         3 . The silica particles according to  claim 1 ,
 wherein the particle size ratio is from 0.04 to 0.1.   
     
     
         4 . The silica particles according to  claim 1 ,
 wherein a particle size of the maximum value of the large-size side is from 50 nm to 500 nm.   
     
     
         5 . The silica particles according to  claim 1 ,
 wherein a particle size of the maximum value of the large-size side is from 80 nm to 400 nm.   
     
     
         6 . The silica particles according to  claim 1 ,
 wherein a particle size of the maximum value of the large-size side is from 100 nm to 300 nm.   
     
     
         7 . The silica particles according to  claim 1 ,
 wherein a particle size of the maximum value of the small-size side is from 5 nm to 80 nm.   
     
     
         8 . The silica particles according to  claim 1 ,
 wherein the number ratio is from 10 to 80.   
     
     
         9 . The silica particles according to  claim 1 ,
 wherein a number average particle diameter is from 100 nm to 200 nm.   
     
     
         10 . A method of preparing silica particles, comprising:
 preparing an alkaline catalyst solution in which an alcohol-containing solvent contains an alkaline catalyst at a concentration of from 0.6 mol/L to 1.0 mol/L; and   supplying tetraalkoxysilane and an alkaline catalyst into the alkaline catalyst solution,   wherein the supplying satisfies the following conditions,   within a range of from A/2 to A, there is a part where C/B is from 15 (mol/L)/{(mol/min)L} to 60 (mol/L)/{(mol/min)L},   wherein, A represents the total amount of the tetraalkoxysilane supplied, B represents (a flow rate of the tetraalkoxysilane supplied)/(a total amount of a solution formed when the tetraalkoxysilane and an alkaline catalyst are supplied into the alkaline catalyst solution), and C represents a concentration of water in a reaction system.   
     
     
         11 . The method of preparing silica particles according to  claim 10 ,
 wherein a concentration of the alkaline catalyst is in a range of from 0.63 mol/L to 0.78 mol/L.   
     
     
         12 . The method of preparing silica particles according to  claim 10 ,
 wherein C/B is from 20 (mol/L)/{(mol/min)L} to 50 (mol/L)/{(mol/min)L}.   
     
     
         13 . The method of preparing silica particles according to  claim 10 ,
 wherein C/B is from 25 (mol/L)/{(mol/min)L} to 40 (mol/L)/{(mol/min)L}.   
     
     
         14 . The method of preparing silica particles according to  claim 10 ,
 wherein the amount of the tetraalkoxysilane supplied is 0.002 mol/(mol·min) or more and less than 0.006 mol/(mol·min) based on the mole number of the alcohol in the alkaline catalyst solution.   
     
     
         15 . The method of preparing silica particles according to  claim 10 ,
 wherein the tetraalkoxysilane is selected from tetramethoxysilane, tetraethoxysilane, tetrapropoxysilane, and tetrabutoxysilane.   
     
     
         16 . The method of preparing silica particles according to  claim 10 ,
 wherein the alkaline catalyst is selected from ammonia, urea, monoamine, and a quaternary ammonium salt.