Surface functionalized titanium dioxide nanoparticles

Patent metadata

Field	Value
Publication number	US-11274219-B2
Application number	US-201816631617-A
Country	US
Kind code	B2
Filing date	Jul 16, 2018
Priority date	Jul 20, 2017
Publication date	Mar 15, 2022
Grant date	Mar 15, 2022

Abstract

The present invention relates to surface functionalized titanium dioxide nanoparticles, a method for its production, a coating composition, comprising the surface functionalized titanium dioxide nanoparticles and the use of the coating composition for coating holo-grams, wave guides and solar panels. Holograms are bright and visible from any angle, when printed with the coating composition, comprising the surface functionalized tita-nium dioxide nanoparticles.

First claim

The invention claimed is:

1. Surface functionalized titanium dioxide nanoparticles treated with
a) a phosphonate of formula:

or a mixture of phosphonates of formula (I), wherein:
R 1 and R 2 are independently of each other hydrogen, or a C 1 -C 4 alkyl group,
R 3 is a group CH 2 ═CH—, or a group of formula —[CH 2 ] n —R 4 , wherein
n is an integer of 1 to 12,
when n>3 one —CH 2 — may be replaced by —S— with a proviso that S is not directly linked to P, or R 4 ,
R 4 is hydrogen, or a group of formula

R 5 is hydrogen, or a C 1 -C 4 alkyl group,
R 6 is hydrogen, or a C 1 -C 4 alkyl group,
X 1 is O, or NH, and
b) bonded with an alkoxide of formula R 7 O − (II) and/or

wherein:
R 7 is a C 1 -C 8 alkyl group, which may be interrupted one or more times by —O— and/or substituted one or more times by —OH,
R 8 is hydrogen, or a C 1 -C 4 alkyl group,
R 9 is hydrogen, —CH 2 OH, —CH 2 SPh, —CH 2 OPh, or a group of formula R 10 —[CH 2 OH—O—CH 2 ] n1 —,
n1 is an integer of 1 to 5,
X 2 is O, or NH,
R 10 is a group of formula —CH 2 —X 3 —CH 2 —C(═O)—CR 11 ═CH 2 ,
X 3 is O, or NH, and
R 11 is hydrogen, or a C 1 -C 4 alkyl group.

2. The surface functionalized titanium dioxide nanoparticles according to claim 1 , which have a size from 1 nm to 40 nm.

3. The surface functionalized titanium dioxide nanoparticles according to claim 1 , wherein a weight ratio of titanium dioxide nanoparticles to phosphonate(s) of formula (I) and alkoxide(s) of formula (II) and (III) is in the range of from 99-1 to 50-50.

4. The surface functionalized titanium dioxide nanoparticles according to claim 3 , wherein the weight ratio of phosphonate(s) of formula (I) and alkoxide(s) of formula (II) and (III) varies from 1-99 to 50-50.

5. The surface functionalized titanium dioxide nanoparticles according to claim 1 , which exhibit a refractive index of greater than 1.70, when coated on a glass plate and dried at 60° C.

6. The surface functionalized titanium dioxide nanoparticles according to claim 1 , wherein in the phosphonate of formula (I):
R 1 and R 2 are hydrogen,
R 3 is a group CH 2 ═CH—, or a group of formula —[CH 2 ] n —R 4 , wherein
n is an integer of 1 to 5, and
R 4 is hydrogen, or a group of formula

7. The surface functionalized titanium dioxide nanoparticles according to claim 1 , wherein the alkoxide of formula (III) is derived from at least one of the following alcohols:

8. The surface functionalized titanium dioxide nanoparticles according to claim 1 , which is:
a) treated with a phosphonate of formula

and
b) bonded with an alkoxide of formula EtO − (D-2), iPropO − (D-4) and

or
a) treated with a phosphonate of formula

and
b) bonded with an alkoxide of formula EtO − (D-2) and iPropO − (D-4).

9. A coating composition, comprising the surface functionalized titanium dioxide nanoparticles according to claim 1 and a solvent.

10. A method for forming a surface relief microstructure on a substrate, the method comprising:
a) forming a surface relief microstructure on a discrete portion of the substrate; and
b) depositing the coating composition according to claim 9 , on at least a portion of the surface relief microstructure.

11. The method according to claim 10 , wherein step a) comprises:
a1) applying a curable compound to at least a portion of the substrate;
a2) contacting at least a portion of the curable compound with surface relief microstructure forming means; and
a3) curing the curable compound.

12. A process, comprising coating an article with the coating composition according to claim 9 , where the article is selected from the group consisting of a hologram, a wave guide and a solar panel.

13. A security, or decorative element, comprising a substrate, which may contain indicia or other visible features in or on its surface, and on at least part of the said substrate surface, a coating, comprising the surface functionalized titanium dioxide nanoparticles according to claim 1 .

14. A process for preparing titanium dioxide nanoparticles, the process comprising:
(a) adding a solution of concentrated hydrogen chloride and diluting the solution with half volume of distilled water, diluting the solution with additional ethanol resulting in solution I to a solution of titanium-tetra-iso-propoxide first stirred in absolute ethanol resulting in a solution II, both volumes of the solutions I and II being equal, to obtain a clear solution,
(b) stirring the obtained clear solution for 5 days at room temperature, and
(c) evaporating the clear solution at 20-30° C./20 mm until a constant weight is achieved to obtain titanium dioxide nanoparticles.

15. The process according to claim 14 , comprising:
d) dissolving the titanium dioxide nanoparticles obtained in step c) in a solvent,
e) adding a phosphonate(s) of formula (I)

and, optionally adding an alcohol of formula

obtaining a mixture having a weight, and
stirring the mixture obtained in step (e) until a transparent solution is obtained, and evaporating the mixture until the weight remains constant, wherein:
R 8 is hydrogen, or a C 1 -C 4 alkyl group,
R 9 is hydrogen, —CH 2 OH, —CH 2 SPh, —CH 2 OPh, or a group of formula R 10 —[CH 2 OH—O—CH 2 ] n1 —,
n1 is an integer of 1 to 5,
X 2 is O, or NH,
R 10 is a group of formula —CH 2 —X 3 —CH 2 —C(═O)—CR 11 ═CH 2 ,
X 3 is O, or NH, and
R 11 is hydrogen, or a C 1 -C 4 alkyl group.

16. Titanium dioxide nanoparticles obtained by the process according to claim 14 , which have a particle size from 1 nm to 40 nm and a TiO 2 -content of at least 40% by weight, a film of which dried at 25° C. shows a refractive index of greater than 1.70 (589 nm).

17. The titanium dioxide nanoparticles according to claim 16 , which are storable at 4° C. for at least 3 months and can be redissolved in methanol, ethanol, propanol, 2-methoxy ethanol, iso-propanol, 2-iso-propoxy ethanol, butanol, ethyl acetate, propyl acetate and butyl acetate.

Assignees

• Basf Se

Inventors

• Oehrlein Reinhold
• Dabbous Raphael
• Richert Michelle
• Baisch Gabriele

Classifications

• B42D25/378

  Special inks · CPC title

• B42D25/36

  comprising special materials · CPC title

• B42D25/324

  Reliefs · CPC title

• C01G23/0536

  by hydrolysing chloride-containing salts · CPC title

• C09C1/3669

  Treatment with low-molecular organic compounds · CPC title