Pigment with photocatalytic activity, method for the production thereof and coating agent

Patent metadata

Field	Value
Publication number	US-9701845-B2
Application number	US-201314440629-A
Country	US
Kind code	B2
Filing date	Nov 5, 2013
Priority date	Nov 6, 2012
Publication date	Jul 11, 2017
Grant date	Jul 11, 2017

Abstract

The invention relates to pigments with a non-metallic substrate, wherein the pigments have at least one barrier layer that selectively absorbs light and/or electrons and at least one photocatalytically active layer, wherein the at least one barrier layer is arranged between the non-metallic substrate and the at least one photocatalytically active layer. The invention furthermore relates to a method for producing the pigments and to a coating agent.

First claim

The invention claimed is:

1. A pigment comprising a non-metallic substrate,
wherein the pigment has at least one barrier layer that selectively absorbs light, electrons, or light and electrons and
at least one photocatalytically active layer comprising at least one of titanium oxide, titanium hydroxide and titanium oxide hydrate,
wherein the photocatalytically active layer has an average thickness of ≦40 nm,
wherein the at least one barrier layer is arranged between the non-metallic substrate and the at least one photocatalytically active layer,
wherein the barrier layer comprises at least one of metal oxide, metal hydroxide and metal oxide hydrate,
wherein the metal is selected from the group consisting of cerium, zinc and mixtures thereof,
wherein the at least one photocatalytically active layer is the outermost inorganic layer, and
wherein the barrier layer has a proportion by weight of from 0.1 to less than 5 wt. %, relative to the total weight of the pigment.

2. The pigment according to claim 1 , wherein the photocatalytically active layer is selected from the group consisting of titanium oxide, titanium hydroxide, titanium oxide hydrate and mixtures thereof.

3. The pigment according to claim 2 , wherein the photocatalytically active layer is doped with carbon, nitrogen, cerium, aluminum, tin, iron and/or zinc.

4. The pigment according to claim 1 , wherein the photocatalytically active layer has a proportion by weight of from 2 to less than 30 wt.-%, relative to the total weight of the pigment.

5. The pigment according to claim 1 , wherein the photocatalytically active layer has an average layer thickness of from 5 to 40 nm.

6. The pigment according to claim 1 , wherein the non-metallic substrate is spherical or platelet-shaped.

7. The pigment according to claim 1 , wherein the pigment is spherical and has an average diameter D 50 of from 10 to 100 μm.

8. The pigment according to claim 1 , wherein the pigment is platelet-shaped and has an average diameter D 50 of from 2 to 65 μm.

9. The pigment according to claim 1 , wherein at least one further inorganic layer is arranged between the at least one barrier layer and the at least one photocatalytically active layer.

10. The pigment according to claim 9 , wherein the at least one further inorganic layer has a proportion by weight of from 0.1 to less than 10 wt. %, relative to the total weight of the pigment.

11. The pigment according to claim 1 , wherein the photocatalytically active layer is organic-chemically modified.

12. The pigment according to claim 10 , wherein the non-metallic substrate is platelet-shaped, and has a coating further comprising a second layer (b), wherein the coating, starting from the substrate, consists of the following layers:
(a) at least one of metal oxide(s), hydroxide(s) and metal oxide hydrate(s) of cerium in an amount of from 0.1 to 1.4 wt.-%, relative to the total weight of the pigment,
(b) at least one of metal oxide(s), hydroxide(s) and metal oxide hydrate(s) of silicon in an amount of from 0.4 to 2.2 wt.-%, relative to the total weight of the pigment,
(c) at least one of metal oxide(s), hydroxide(s) and metal oxide hydrate(s) of titanium in an amount of from 5.2 to 24.0 wt.-%, relative to the total weight of the pigment, and
(d) optionally an organic-chemical surface modification.

13. The pigment with a non-metallic substrate according to claim 10 , wherein the non-metallic substrate is platelet-shaped, and has a coating further comprising a second layer (b), wherein the coating, starting from the substrate, consists of the following layers:
(a) at least one of metal oxide(s), hydroxide(s) and metal oxide hydrate(s) of zinc in an amount of from 0.3 to 2.9 wt.-%, relative to the total weight of the pigment,
(b) at least one of metal oxide(s), hydroxide(s) and metal oxide hydrate(s) of silicon in an amount of from 0.4 to 2.5 wt.-%, relative to the total weight of the pigment,
(c) at least one of metal oxide(s), hydroxide(s) and metal oxide hydrate(s) of titanium in an amount of from 4.9 to 22.5 wt.-%, relative to the total weight of the pigment, and
(d) optionally an organic-chemical surface modification.

14. A coating agent, wherein the coating agent comprises a pigment according to claim 1 .

15. A method for producing a pigment according to claim 1 , wherein the method comprises the following steps:
(a) coating a non-metallic substrate with the at least one barrier layer,
(b) coating the non-metallic substrate provided with the at least one barrier layer with the at least one photocatalytically active layer.

16. The pigment according to claim 1 , wherein the barrier layer consists of metal oxide, metal hydroxide and/or metal oxide hydrate.

17. The pigment according to claim 1 , wherein the non-metallic substrate is natural mica platelet, synthetic mica platelet, or glass platelet.

18. The pigment according to claim 12 , wherein the non-metallic substrate is natural mica platelet, synthetic mica platelet, or glass platelet.

19. The pigment according to claim 13 , wherein the non-metallic substrate is natural mica platelet, synthetic mica platelet, or glass platelet.

20. A pigment comprising a non-metallic substrate,
wherein the pigment has at least one barrier layer that selectively absorbs light, electrons, or light and electrons and
at least one photocatalytically active layer comprising at least one of titanium oxide, titanium hydroxide and titanium oxide hydrate,
wherein the photocatalytically active layer has an average thickness of ≦40 nm,
wherein the at least one barrier layer is arranged between the non-metallic substrate and the at least one photocatalytically active layer,
wherein the barrier layer comprises at least one of metal oxide, metal hydroxide and metal oxide hydrate,
wherein the metal is selected from the group consisting of cerium, zinc and mixtures thereof,
wherein the at least one photocatalytically active layer is the outermost inorganic layer,
wherein the barrier layer has a proportion by weight of from 0.1 to less than 5 wt. %, relative to the total weight of the pigment, and
wherein said pigment is achromatic and does not have a silver interference color.

21. A pigment comprising a non-metallic substrate,
wherein the pigment has at least one barrier layer that selectively absorbs light, electrons, or light and electrons and
at least one photocatalytically active layer comprising at least one of titanium oxide, titanium hydroxide and titanium oxide hydrate,
wherein the photocatalytically active layer has an average thickness of ≦40 nm,
wherein the at least one barrier layer is arranged between the non-metallic substrate and the at least one photocatalytically active layer,
wherein the barrier layer comprises at least one of metal oxide, metal hydroxide and metal oxide hydrate,
wherein the metal is selected from the group consisting of cerium, zinc and mixtures thereof,
wherein at least one further inorganic layer is arranged between the at least one barrier layer and the at least one photocatalytically active layer, and the at least one further inorganic layer has a proportion by weight of from 0.1 to less than 10 wt. %, relative to the total weight of the pigment,
wherein the non-metallic substrate is platelet-shaped, and has a coating further comprising a second layer (b), wherein the coating, starting from the substrate, consists of the following layers (I) or layers (II),
layers (I),
(a) at least one of metal oxide(s), hydroxide(s

Assignees

• Eckart Gmbh

Inventors

• Grüner Michael
• Kaupp Günter

Classifications

• B01J35/395

  Thickness of the active catalytic layer · CPC title

• B01J2235/00

  Indexing scheme associated with group B01J35/00, related to the analysis techniques used to determine the catalysts form or properties · CPC title

• B01J2235/30

  Scanning electron microscopy; Transmission electron microscopy · CPC title

• C09C1/0057

  comprising at least one light-absorbing layer · CPC title

• C09C2200/407

  Organosilicon materials, e.g. silanes, silicones · CPC title