Method for producing zirconia colloids

Patent metadata

Field	Value
Publication number	US-9250360-B2
Application number	US-201414151434-A
Country	US
Kind code	B2
Filing date	Jan 9, 2014
Priority date	Jul 12, 2011
Publication date	Feb 2, 2016
Grant date	Feb 2, 2016

Abstract

The present invention pertains to a method for producing a colloidal suspension of zirconia particles, including successively subjecting a mixture of zirconium oxychloride and an alkali metal halide in an aqueous solvent to hydrothermal treatment at a temperature above 150° C, separating the slurry obtained from the supernatant, and peptizing said slurry by adding a strong acid thereto, and desalting said slurry, for example by ultrafiltration, so as to form a colloidal suspension of zirconia. The present invention also pertains to the transparent colloidal suspension obtainable by this method, and to an optical article, such as an ophthalmic lens, comprising a transparent polymer substrate and at least one coating prepared from a composition comprising said colloidal suspension.

First claim

The invention claimed is:

1. A method for producing a colloidal suspension of zirconia particles, comprising the following successive steps:
a) subjecting a mixture of zirconium oxychloride (ZrOCl 2 ) and an alkali metal halide in an aqueous solvent to hydrothermal treatment at a temperature above 150° C.,
b) separating a slurry obtained from a supernatant in step (a), and
c) peptizing said slurry by adding a strong acid thereto, and
d) desalting said slurry, so as to form the colloidal suspension of zirconia particles.

2. The method according to claim 1 , wherein the alkali metal halide is potassium chloride.

3. The method according to claim 1 , wherein the zirconium oxychloride and the alkali metal halide are mixed in a molar ratio of the alkali metal halide/ZrOCl 2 from 1/10 to 1/1.

4. The method according to claim 3 , wherein the molar ratio of alkali metal halide/ZrOC 1 2 is from 1/4 to 1/2.

5. The method according to claim 1 , wherein the zirconium oxychloride concentration in said mixture ranges from 0.5 to 4 mol/l.

6. The method according to claim 5 , wherein the zirconium oxychloride concentration in said mixture ranges from 1 to 2 mol/ 1 .

7. The method according to claim 1 , wherein the hydrothermal treatment is conducted at a temperature from 150 to 220° C. during at least one day.

8. The method according to claim 7 , wherein the hydrothermal treatment is conducted at a temperature from 160 to 200° C. during at least one day.

9. The method according to claim 8 , wherein the hydrothermal treatment is conducted at a temperature from 170 to 190° C. during at least one day.

10. The method according to claim 1 , wherein peptizing is conducted by means of hydrochloric acid.

11. The method according to claim 1 , wherein the method further includes a step of pH modification by addition of an inorganic or organic base.

12. The method according to claim 1 , wherein the method further includes a step of improving zirconia dispersion, either by adding a dispersant, or by surface modification of the zirconia particles.

13. The method according to claim 1 , wherein it further includes a step of dialysis so as to substitute at least one alcoholic solvent for the aqueous solvent.

14. A transparent colloidal suspension of zirconia particles obtainable by the method according to claim 1 , wherein the zirconia particles are provided in the form of single monoclinic rod-like crystallites, the dimensions of which range from 1 to 15 nm along their short axis and from 3 to 30 nm along their long axis.

15. The transparent colloidal suspension according to claim 14 , wherein the transparent colloidal suspension has a zeta potential of at least 30 mV in absolute value.

16. The transparent colloidal suspension according to claim 14 , wherein the transparent colloidal suspension has a solid content of at least 15 wt. %.

17. The transparent colloidal suspension according to claim 16 , wherein the transparent colloidal suspension has a solid content of at least 20 wt. %.

18. The transparent colloidal suspension according to claim 14 , wherein the zirconia particles have a refractive index of at least 1.8.

19. The transparent colloidal suspension according to claim 14 , wherein a pH is under 6 and the transparent colloidal suspension is free of stabilizer.

20. An optical article comprising a transparent polymer substrate and at least one coating prepared from a composition comprising a colloidal suspension according to claim 14 .

Assignees

• Essilor Int
• Univ Shanghai

Inventors

• Leclaire Yves
• Zhao Jian
• Shi Liyi
• Wang Zhuyi
• Yuan Shuai
• Zhao Yin

Classifications

• B01J13/0047 Primary

  containing a metal oxide · CPC title

• C01P2002/72

  by d-values or two theta-values, e.g. as X-ray diagram · CPC title

• G02B1/113

  using inorganic layer materials only · CPC title

• B82Y30/00

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

• C01P2006/22

  Rheological behaviour as dispersion, e.g. viscosity, sedimentation stability · CPC title