Effect pigments with high chroma and high brilliancy, method for the production and use thereof

Patent metadata

Field	Value
Publication number	US-10799432-B2
Application number	US-201916504553-A
Country	US
Kind code	B2
Filing date	Jul 8, 2019
Priority date	Dec 19, 2014
Publication date	Oct 13, 2020
Grant date	Oct 13, 2020

Abstract

The invention relates to an absorbent effect pigment including a nonmetallic substrate in platelet form and a coating applied thereto, wherein the coating includes at least one spacer layer. The invention further relates to a process for production of and to the use of the absorbent effect pigment.

First claim

The invention claimed is:

1. An absorbent effect pigment comprising a nonmetallic substrate in platelet form and a coating applied to the substrate, wherein the coating includes
a) optionally a layer 1 comprising or consisting of at least one of tin oxide, tin hydroxide or tin oxide hydrate,
b) a layer 2 comprising at least one of metal oxide, metal hydroxide or metal oxide hydrate,
c) a layer 3 comprising at least one of metal oxide, metal hydroxide or metal oxide hydrate,
at least one of layers 2 and 3 comprises at least two different metal ions and layers 2 and 3 are interrupted by a spacer layer, wherein the at least one spacer layer includes connections and cavities and wherein the at least one spacer layer has a network density of <85%.

2. The absorbent effect pigment as claimed in claim 1 , wherein the nonmetallic substrate in platelet form is selected from the group consisting of natural mica platelets, synthetic mica platelets, iron mica, glass platelets, SiO 2 platelets, Al 2 O 3 platelets, kaolin platelets, talc platelets, bismuth oxychloride platelets and mixtures thereof, and the nonmetallic substrate in platelet form has optionally been coated with at least one metal oxide, metal hydroxide and metal oxide hydrate.

3. The absorbent effect pigment as claimed in claim 1 , wherein the effect pigment comprises further layers of high and/or low refractive index and optionally at least one further spacer layer.

4. The absorbent effect pigment as claimed in claim 1 , wherein the at least two different metal ions of layers 2 and 3 are selected from the group of metals consisting of Ti, Fe, Sn, Mn, Zr, Ca, Sr, Ba, Ni, Sb, Ag, Zn, Cu, Ce, Cr and Co, and wherein the proportion of noncoloring metal ions selected from the group of the metals consisting of Ti, Sn, Zr, Ca, Sr, Ba and Zn totals ≤ 40% by weight, and the proportion of coloring metal ions selected from the group of the metals consisting of Fe, Ti, Sn, Mn, Ni, Sb, Ag, Cu, Ce, Cr and Co totals ≥ 4% by weight, determined by means of XRF in each case, calculated in each case as the elemental metal and based in each case on the total weight of the absorbent effect pigment of the invention.

5. The absorbent effect pigment as claimed in claim 1 , wherein a weight ratio, determined by means of XRF and calculated as the elemental metal, of noncoloring metal ions to coloring metal ions in the absorbent effect pigment of the invention is < 20.

6. The absorbent effect pigment as claimed in claim 1 , wherein the at least one spacer layer is arranged essentially parallel to the surface of the nonmetallic substrate in platelet form.

7. The absorbent effect pigment as claimed in claim 1 , wherein the at least one spacer layer has a mean height h a ranging from 5 nm to 120 nm.

8. The absorbent effect pigment as claimed in claim 1 , wherein the network density is in a range from 1% to 75%.

9. The absorbent effect pigment as claimed in claim 1 , wherein the network density is in a range from 1% to 63%.

10. The absorbent effect pigment as claimed in claim 1 , wherein the network density is defined as the number of connections or spacers per number of lines in %, wherein said lines are drawn at 50 nm intervals in a scanning electron micrograph of a cross section of the effect pigments in a hardened lacquer, wherein the lines are established by the steps:
establishing the upper and lower surfaces as baselines which are the longer side of the nonmetallic substrate in platelet form and drawing the baselines onto the scanning electron micrographs of the traverse section;
analyzing the scanning electron micrographs of the traverse sections with the aid of the AxioVision 4.6.3 image processing software (from Zeiss);
drawing a sufficient number of parallel lines at 50 nm intervals at a 90° angle with respect to the upper and lower baselines corresponding to the two surfaces of the substrate in platelet form establishing a grid over the effect pigment shown in the scanning electron micrograph of the traverse section ( FIG. 4 ) using a magnification of at least 50,000-fold, based on Polaroid 545 (4″×5″).

11. The absorbent effect pigment as claimed in claim 1 , wherein the mean layer thickness of optional layer 1 is less than 10 nm and the mean layer thickness of each of layers 2 and 3 of the absorbent effect pigments of the invention is within a range from 30 nm to 350 nm.

12. The absorbent effect pigment as claimed in claim 1 , wherein the mean layer thickness of optional layer 1 is less than 10 nm and the mean layer thickness of each of layers 2 and 3 of the absorbent effect pigments of the invention is within a range from 35 nm to 310 nm.

13. A process for producing the absorbent effect pigment as claimed in claim 1 ,
wherein the process comprises:
(i) optionally applying an uncalcined layer comprising or consisting of at least one of tin oxide, tin hydroxide or tin oxide hydrate to the nonmetallic substrate in platelet form,
(ii) sequentially applying three uncalcined layers A, B and C each consisting of or comprising at least one of metal oxide, metal hydroxide or metal oxide hydrate, where the layers A, B and C are arranged directly one on top of another and where the at least one metal oxide, metal hydroxide or metal oxide hydrate applied in the layer B, in relation to the metal ion, is different than the metal ion(s) of the metal oxides, metal hydroxides and/or metal oxide hydrates of layer A and layer C,
(iii) calcining the product obtained in step (ii) at a temperature ranging from 400° C. to 1000° C. to obtain the absorbent effect pigment comprising at least one spacer layer.

14. The process as claimed in claim 13 , wherein the metal ions present in layer B diffuse at least partly into layer A and/or layer C to form the at least one spacer layer in the calcined effect pigment.

15. The process as claimed in claim 13 , wherein the two or three sequentially applied metal oxides, metal hydroxides and/or metal oxide hydrates for production of the layers B and C or the layers A, B and C do not comprise any metal ion selected from the group of the metals consisting of Si, Mg and Al.

16. A process for producing the absorbent effect pigment as claimed in claim 1 , wherein the process comprises the following steps:
(i) sequentially applying two uncalcined layers B and C each consisting of or comprising at least one of metal oxide, metal hydroxide or metal oxide hydrate to a calcined, singly or multiply coated nonmetallic substrate, where the layers B and C are arranged directly one on top of another and where the at least one metal oxide, metal hydroxide and/or metal oxide hydrate applied in the layer B, in relation to the metal ion, is different than the metal ion(s) of the metal oxide, metal hydroxide and/or metal oxide hydrate of layer C and of the layer which directly adjoins layer B in the substrate direction,
(ii) calcining the product obtained in step (i) at a temperature ranging from 400° C. to 1000° C. to obtain the absorbent effect pigment comprising at least one spacer layer.

17. The process according to claim 16 , wherein the metal ions present in layer B diffuse at least partly into layer A and/or layer C to form the at least one spacer layer in the calcined effect pigment.

18. A process for producing a pigmented cosmetic formulation, plastic, film, textile, ceramic material, glass, paint, printing ink, writing ink, varnish, powder coating or a material for a functional application comprising introducing the absorbent effect pigment of claim 1 into a cosmetic formulation, plastic, film, textile, ceramic m

Assignees

• Eckart Gmbh

Inventors

• Grüner Michael
• Kaupp Günter
• Schneider Ralph

Classifications

• C09C1/0015 Primary

  Pigments exhibiting interference colours, e.g. transparent platelets of appropriate thinness or flaky substrates, e.g. mica, bearing appropriate thin transparent coatings · CPC title

• A61K2800/436

  Interference pigments, e.g. Iridescent, Pearlescent · CPC title

• C01P2004/03

  obtained by SEM · CPC title

• C01P2004/51

  Particles with a specific particle size distribution · CPC title

• C01P2004/61

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