US 12,662,385 B2
Hydrophobic silica particles, use of same, and method for producing hydrophobic silica particles
Shinnosuke Arimitsu, Fukuoka (JP); and Naoyuki Izumi, Fukuoka (JP)
Assigned to AGC SI-TECH CO., LTD., Kitakyushu (JP)
Filed by AGC SI-TECH CO., LTD., Kitakyushu (JP)
Filed on Jun. 21, 2023, as Appl. No. 18/338,725.
Application 18/338,725 is a continuation of application No. PCT/JP2021/046393, filed on Dec. 15, 2021.
Claims priority of application No. 2020-217209 (JP), filed on Dec. 25, 2020; and application No. 2021-081180 (JP), filed on May 12, 2021.
Prior Publication US 2023/0348283 A1, Nov. 2, 2023
Int. Cl. C01B 33/12 (2006.01)
CPC C01B 33/124 (2013.01) [C01P 2006/12 (2013.01)] 7 Claims
 
1. A composition of hydrophobic silica particles comprising hydrophobic silica particles impregnated with a higher alcohol having 19 or more carbon atoms, the composition of hydrophobic silica particles having:
an average particle diameter of from 2 μm to 7.2 μm,
an oil absorption value of from 20 mL/100 g to 400 mL/100 g,
a circularity of 0.95 or more
an impregnation amount of the higher alcohol of 1.0 μmol/m2 or more, and
a binding degree of the higher alcohol to the silica particles of 70% or more;
wherein the binding degree of the higher alcohol to the silica particles is measured by the following measuring method:
1 g of the hydrophobic silica particles is dispersed in 10 mL of tetrahydrofuran, and after maintaining the dispersed state for 5 minutes, a filtered residue is washed with 20 mL of tetrahydrofuran and 20 mL of hexane and dried, and a ratio, which is represented by Equation (1) shown below, of a carbon content of the hydrophobic silica particles after washing to a carbon content of the hydrophobic silica particles before washing is defined as the binding degree,
wherein the binding degree (%)=carbon content (%) of hydrophobic silica particles after washing/carbon content (%) of hydrophobic silica particles before washing×100 (1); and
wherein the hydrophobic silica particles are capable of forming a stable dispersion in a liquid paraffin phase.