Hydrophobic-treated metal oxide

Patent metadata

Field	Value
Publication number	US-10407571-B2
Application number	US-201715454089-A
Country	US
Kind code	B2
Filing date	Mar 9, 2017
Priority date	Sep 15, 2006
Publication date	Sep 10, 2019
Grant date	Sep 10, 2019

Abstract

This invention provides metal oxide particles surface-treated with a hydrophobicity-imparting agent, methods of making such, and toner compositions comprising the same.

First claim

The invention claimed is:

1. A method of preparing hydrophobic metal oxide particles comprising
(a) providing an aqueous dispersion of non-aggregated metal oxide particles, wherein the aqueous dispersion is basic,
(b) combining the dispersion with a first hydrophobicity-imparting agent to provide a reaction mixture, wherein the first hydrophobicity-imparting agent is an alkoxysilane compound selected from the group consisting of monoalkoxysilane compounds, dialkoxysilane compounds, and trialkoxysilane compounds,
(c) maintaining the reaction mixture at a temperature of about 40° C. to about 100° C., and
(d) drying the reaction mixture to provide hydrophobic, non-aggregated, metal oxide particles in the form of a dry powder, wherein the hydrophobic metal oxide particles contain substantially no free alkali metal cations, and wherein a carbon content of the hydrophobic metal oxide particles is from about 3 wt % to about 8 wt % and a solid-state Si nuclear magnetic resonance spectrum of the hydrophobic metal oxide particles exhibits a ratio T3:T2 of about 0.4 to about 10, wherein T2 is the intensity of a peak having a chemical shift in the CP/MAS 29 Si NMR spectrum centered within the range of 56 ppm to 59 ppm, and wherein T3 is the intensity of a peak having a chemical shift in the CP/MAS 29 Si NMR spectrum centered within the range of −65 ppm to −69 ppm.

2. The method of claim 1 , wherein the first hydrophobicity-imparting agent is a trialkoxysilane compound.

3. The method of claim 2 , wherein the trialkoxysilane compound is octyltriethoxysilane.

4. The method of claim 1 , wherein part (b) further comprises combining the dispersion with a second hydrophobicity-imparting agent.

5. The method of claim 4 , wherein the second hydrophobicity-imparting agent is an aza-silane.

6. The method of claim 4 , wherein the second hydrophobicity-imparting agent is an aminoalkylsilane.

7. The method of claim 4 , wherein the second hydrophobicity-imparting agent is hexamethyldisilazane.

8. The method of claim 1 , wherein an agglomerate particle size of the hydrophobic metal oxide particles is reduced after the dispersion is dried.

9. The method of claim 1 , wherein the dispersion is prepared by mixing an aqueous metal oxide dispersion with a water-miscible organic solvent, before contacting the metal oxide particles with the first hydrophobicity-imparting agent.

10. The method of claim 4 , wherein the dispersion is prepared by mixing an aqueous metal oxide dispersion with a water-miscible organic solvent, before contacting the metal oxide particles with the second hydrophobicity-imparting agent.

11. The method of claim 10 , wherein the organic solvent to water volume ratio is between about 0.2 and about 2.

12. The method of claim 1 , wherein the reaction mixture is maintained at a temperature between about 40° C. and about 80° C. for about 1 hour or longer.

13. The method of claim 1 , wherein the dispersion comprises between about 10 wt. % and about 45 wt. % metal oxide particles.

14. The method of claim 1 , wherein the metal oxide particles are colloidal silica particles.

15. The method of claim 14 , wherein the colloidal silica particles are prepared from an alkali silicate.

16. The method of claim 1 , wherein the aqueous dispersion has a pH of about 8 to about 11.

Assignees

• Cabot Corp

Inventors

• Fomitchev Dmitry
• Floess Joachim K
• Williams William R
• Tu Hairuo

Classifications

• C01P2004/62

  Submicrometer sized, i.e. from 0.1-1 micrometer · CPC title

• C01P2006/10

  Solid density · CPC title

• C01P2002/86

  by NMR- or ESR-data · CPC title

• G03G9/09725

  Silicon-oxides; Silicates · CPC title

• B82Y30/00

  Nanotechnology for materials or surface science, e.g. nanocomposites · CPC title