Porous Metal Oxide Microspheres

Patent metadata

Field	Value
Publication number	US-2019076809-A1
Application number	US-201816126338-A
Country	US
Kind code	A1
Filing date	Sep 10, 2018
Priority date	Sep 11, 2017
Publication date	Mar 14, 2019
Grant date	—

Abstract

Porous metal oxide microspheres are prepared via a process comprising forming a liquid dispersion of polymer nanoparticles and a metal oxide; forming liquid droplets of the dispersion; drying the droplets to provide polymer template microspheres comprising polymer nanospheres; and removing the polymer nanospheres from the template microspheres to provide the porous metal oxide microspheres. The porous microspheres exhibit saturated colors and are suitable as colorants for a variety of end-uses.

First claim

1 . A method to prepare porous metal oxide microspheres comprising a metal oxide, the method comprising
forming a liquid dispersion of polymer nanoparticles and a metal oxide; forming liquid droplets of the dispersion; drying the liquid droplets to provide polymer template microspheres comprising polymer nanospheres and metal oxide; and removing the polymer nanospheres from the template microspheres to provide the porous metal oxide microspheres, wherein the microspheres have an average diameter of from about 0.5 μm to about100 μm, an average porosity of from about 0.10 to about 0.80 and an average pore diameter of from about 50 nm to about 999 nm.

2 . A method according to claim 1 , comprising forming a liquid dispersion of polymer nanoparticles and the metal oxide, spray-drying the liquid dispersion to provide polymer template microspheres and removing the polymer nanospheres from the template microspheres.

3 . A method according to claim 1 , comprising forming the liquid droplets with a vibrating nozzle.

4 . A method according to claim 1 , wherein the liquid droplets are aqueous droplets or oil droplets.

5 . A method according to claim 1 , comprising providing a continuous phase and mixing the liquid dispersion with the continuous phase to form an emulsion containing dispersed liquid dispersion droplets and collecting the droplets.

6 . A method according to claim 5 , comprising drying the droplets to provide polymer template microspheres comprising polymer nanospheres and metal oxide and removing the polymer nanospheres from the template microspheres.

7 . A method according to claim 6 , wherein drying the droplets comprises microwave irradiation, oven drying, drying under vacuum, drying in the presence of a desiccant, or a combination thereof.

8 . A method according to claim 5 , wherein the droplets are formed in a microfluidic device.

9 . A method according to claim 1 , wherein a wt/wt ratio of polymer nanoparticles to the metal oxide is from about 0.5/1 to about 10.0/1.

10 . A method according to claim 1 , wherein the polymer nanoparticles have an average diameter of from about 50 nm to about 990 nm.

11 . A method according to claim 1 , wherein the polymer is selected from the group consisting of poly(meth)acrylic acid, poly(meth)acrylates, polystyrenes, polyacrylamides, polyethylene, polypropylene, polylactic acid, polyacrylonitrile, derivatives thereof, salts thereof, copolymers thereof and combinations thereof.

12 . A method according to claim 1 , wherein the metal oxide is selected from the group consisting of silica, titania, alumina, zirconia, ceria, iron oxides, zinc oxide, indium oxide, tin oxide, chromium oxide and combinations thereof.

13 . A method according to claim 1 , wherein the porous microspheres are monodisperse.

14 . A method according to claim 1 , wherein the porous metal oxide microspheres are a bulk sample of microspheres.

15 . A method according to claim 1 , wherein removing the polymer nanospheres from the template microspheres comprises calcination, pyrolysis or solvent removal.

16 . A method according to claim 1 , wherein removing the polymer nanospheres comprises calcining the template microspheres at temperatures of from about 350° C. to about 700° C. for a period of from about 1 hour to about 8 hours.

17 . Porous microspheres prepared according to claim 1 .

18 . A bulk sample of porous microspheres prepared according to claim 1 .

19 . Porous microspheres comprising a metal oxide, wherein the microspheres have
an average diameter of from about 1 μm to about 75 μm, an average porosity of from about 0.45 to about 0.65 and an average pore diameter of from about 50 nm to about 800 nm.

20 . The porous microspheres according to claim 1 , wherein the microspheres have an average diameter of from about 1 μm to about 75 μm.

21 . The porous microspheres according to claim 1 , wherein the microspheres have an average pore diameter of from about 50 nm to about 800 nm.

22 . The porous microspheres according to claim 1 , wherein the microspheres have an average porosity of from about 0.45 to about 0.65.

23 . The porous microspheres according to claim 19 , wherein the microspheres have
an average diameter of from about 4.5 μm to about 9.9 μm; an average porosity of from about 0.45 to about 0.65; and an average pore diameter of from about 220 nm to about 300 nm.

24 . The porous microspheres according to claim 19 , comprising from about 60.0 wt % to about 99.9 wt % metal oxide, based on the total weight of the microspheres.

25 . The porous microspheres according to claim 19 , wherein the metal oxide is selected from the group consisting of silica, titania, alumina, zirconia, ceria, iron oxides, zinc oxide, indium oxide, tin oxide, chromium oxide and combinations thereof.

26 . The porous microspheres according to claim 19 , comprising from about 0.1 wt % to about 40.0 wt % of one or more light absorbers, based on the total weight of the microspheres.

27 . The porous microspheres according to claim 19 , wherein a bulk sample of the porous microspheres exhibits color observable by the human eye.

28 . The porous microspheres according to claim 19 , wherein the porous microspheres are monodisperse.

29 . A composition comprising a substrate and the porous microspheres according to claim 19 .

30 . A composition according to claim 29 , wherein the composition is an aqueous formulation, an oil-based formulation, an ink, a coating formulation, a food, a plastic, a cosmetic formulation or a material for a medical application or a security application.

31 . Porous microspheres comprising a metal oxide, wherein a bulk sample of the porous microspheres exhibits color observable by the human eye.

32 . The porous microspheres according to claim 31 , wherein a bulk sample of the porous microspheres exhibits angle-independent color observable by the human eye.

33 . The porous microspheres according to claim 31 , wherein a bulk sample of the porous microspheres exhibits angle-dependent color observable by the human eye.

34 . A composition comprising a substrate and the porous microspheres according to claim 31 .

35 . A composition according to claim 34 , wherein the composition is an aqueous formulation, an oil-based formulation, a coating formulation, a food, an ink, a plastic, a cosmetic formulation or a material for a medical application or a security application.

Assignees

• Harvard College
• Basf Se

Inventors

• Darji Rupa Hiremath
• Newhouse James
• Manoharan Vinothan N
• Hwang Victoria
• Stephenson Anna B

Classifications

• C01P2006/16

  Pore diameter · CPC title

• C01P2004/61

  Micrometer sized, i.e. from 1-100 micrometer · CPC title

• C01G9/02

  Oxides; Hydroxides · CPC title

• C01B13/145

  After-treatment of oxides or hydroxides, e.g. pulverising, drying, decreasing the acidity · CPC title

• C01G9/03

  Processes of production using dry methods, e.g. vapour phase processes · CPC title