Patent ID: 7238387

Claim:
A process for producing hydrophobic inorganic fine particles, comprising: a mixing step of mixing at least small-particle-diameter inorganic fine particles and large-particle-diameter inorganic fine particles to obtain a mixture; and a hydrophobic treatment step of treating the mixture in the same treating tank to subject both said small-particle-diameter inorganic fine particles and said large-particle-diameter inorganic fine particles simultaneously to hydrophobic treatment, wherein said small-particle-diameter inorganic fine particles have an average primary particle diameter of from 5 nm to 25 nm in number-based particle size distribution and have a maximum peak particle diameter of 20 nm or less in number-based particle size distribution; and said large-particle-diameter inorganic fine particles have an average primary particle diameter in number-based particle size distribution which is from 1.5 to 100 times said average primary particle diameter of said small-particle-diameter inorganic fine particles in number-based particle size distribution.