Interference pigments

• US 6,596,070 B1
• Filed: 04/17/2000
• Issued: 07/22/2003
• Est. Priority Date: 10/17/1997
• Status: Expired due to Term

• Current Assignee: Merck Patent GmbH (Merck & Co., Inc.)
• Original Assignee: Merck Patent Gesellschaft Mit Beschränkter Haftung
• Inventors: Schank, Christina, Schoen, Sabine, Schmidt, Christoph, Pfaff, Gerhard
• Primary Examiner(s): Bell, Mark L.
• Assistant Examiner(s): Hailey, Patricia L.
• Application Number:
  US09/529,619
• Time in Patent Office: 1,191 Days
• Field of Search: 106/415, 106/417, 106/418, 106/436, 106/438, 106/439, 106/442, 428/404
• US Class Current: 106/417
• CPC Class Codes: A61K 2800/412 Microsized, i.e. having sizes between 0.1 and 100 microns
• CPC Class Codes: A61K 2800/436 Interference pigments, e.g. Iridescent, Pearlescent
• CPC Class Codes: A61K 2800/621 by inorganic compounds
• CPC Class Codes: A61K 2800/63 More than one coating
• CPC Class Codes: A61K 2800/651 The particulate/core comprising inorganic material
• CPC Class Codes: A61K 8/0266 Characterized by the sequence of layers
• CPC Class Codes: A61Q 1/02 Preparations containing skin colorants, e.g. pigments preparations in powder form A61Q1/12
• CPC Class Codes: C03C 1/10 to produce uniformly-coloured transparent products
• CPC Class Codes: C03C 17/3417 all coatings being oxide coatings
• CPC Class Codes: C08K 9/02 Ingredients treated with inorganic substances
• CPC Class Codes: C09C 1/0024 comprising a stack of coating layers with alternating high and low refractive indices, wherein the first coating layer on the core surface has the high refractive index
• CPC Class Codes: C09C 1/0039 consisting of at least one coloured inorganic material
• CPC Class Codes: C09C 2200/1004 the core comprising at least one inorganic oxide, e.g. Al2O3, TiO2 or SiO2
• CPC Class Codes: C09C 2200/102 the core consisting of glass or silicate material like mica or clays, e.g. kaolin
• CPC Class Codes: C09D 5/36 Pearl essence, e.g. coatings containing platelet-like pigments for pearl lustre
• CPC Class Codes: Y10T 428/2993 Silicic or refractory material containing [e.g., tungsten oxide, glass, cement, etc.]

Abstract

The present invention relates to interference pigments on the basis of multiply coated, platelet-shaped substrates which comprise at least one layer sequence comprising

(A) a coating having a refractive index n≧2.0,

(B) a colorless coating having a refractive index n≦1.8, and

(C) a nonabsorbing coating of high refractive index,

and, if desired,

(D) an external protective layer.

Claims

1. An interference pigment comprising a multiply coated, platelet-shaped substrate (S) having at least one layer sequence comprising

(A) a coating having a refractive index n>

2.0,

(B) a colourless coating having a refractive index n>

1.8, and

(C) a nonabsorbing coating of high refractive index.

2. The interference pigment according to claim 1, wherein between the substrate (S) and the layer (A), the layer (A) and (B), and/or the layer (B) and (C) there is a further colored or colorless metal oxide layer (S1), (A1), (B1) and/or (C1).

3. The interference pigment according to claim 1, wherein the platelet-shaped substrate is natural or synthetic mica, glass, Al₂O₃, SiO₂ or TiO₂ flakes, or a platelet-shaped material coated with at least one metal oxide.

4. The interference pigment according to claim 1, wherein the layers (A), (B) and (C) consist essentially of metal oxides.

5. The interference pigment according to claim 1, wherein the layer (A) consists essentially of titanium dioxide, iron oxide, bismuth oxychloride, zirconium oxide, tin oxide, zinc oxide, titanium suboxides, iron titanates, iron oxide hydrates, chromium oxide, bismuth vanadate, cobalt aluminate or a mixture thereof.

6. The interference pigment according to claim 1, wherein the layer (B) consists essentially of silicon dioxide, aluminum oxide, magnesium fluoride or a mixture thereof.

7. The interference pigment according to claim 1, wherein the layer (C) consist essentially of titanium dioxide, bismuth oxychloride, zirconium oxide, tin oxide, zinc oxide or a mixture thereof.

8. The interference pigment according to claim 1, having the layer sequence (A)-(C) up to four times.

9. The interference pigment according to claim 8, containing only one layer sequence (A)-(C).

10. A process for preparing an interference pigment according to claim 1, comprising applying the metal oxides wet-chemically to the platelet-shaped substrate by hydrolytic decomposition of metal salts in an aqueous medium.

11. A paint, lacquer, printing ink, plastic, ceramic material, glass or cosmetic formulation, comprising an interference pigment according to claim 1.

12. The interference pigment according to claim 1, further comprising (D) an external protective layer.

13. An interference pigment comprising a multiply coated, platelet-shaped substrate having at least one layer sequence comprising

(A) a coating having a refractive index n>

2.0, selected from the group consisting of iron oxide, bismuth oxychloride, zirconium oxide, bismuth vanadate, cobalt aluminate or a mixture thereof,

(B) a colourless coating having a refractive index n>

1.8, selected from the group consisting of titanium dioxide, tin oxide, zinc oxide or a mixture thereof,

(C) a nonabsorbing coating of high refractive index, and,

(D) an external protective layer.