CHAMPAGNE-TONE METAL EFFECT PIGMENTS

Abstract

The present invention relates to metal effect pigments with a high covering power and a thin iron oxide coating, for creating a champagne tone.

Claims

1. A metallic effect pigment based on coated aluminum substrate platelets, where the aluminum substrate platelets have a thickness of 5 to 35 nm, are of monolithic construction, and are surrounded by a native passivation layer of Al.sub.2O.sub.3 of less than 10 nm, where these aluminum substrate platelets are enveloped by at least one coating A of SiO.sub.2 having a layer thickness of 10 to 100 nm, bearing a further, applied coating B of Fe.sub.2O.sub.3 which envelops the substrate platelets having the SiO.sub.2 coating A and which has a layer thickness of 5 to 45 nm, and characterized, for a ΔE45 of ≤3 at not more than 7% pigmentation, more particularly ΔE45° of ≤1 at <7% pigmentation, by a saturation (S.sub.uv) in the range of 0.2-0.3, a value for the hue angle (h.sub.uv) in the range of 50-65, a value for the flop/Alman Index above 26, and a value for the Gdiff (graininess) at not more than 6.

2. The metallic effect pigment as claimed in claim 1, wherein the aluminum substrate platelets have a thickness of 15 to 25 nm.

3. The metallic effect pigment as claimed in claim 1, wherein the SiO.sub.2 coating A has a layer thickness of 20 to 80 nm.

4. The metallic effect pigment as claimed in claim 1, wherein the Fe.sub.2O.sub.3 coating B has a layer thickness of 10 to 45 nm.

5. The metallic effect pigment as claimed in claim 1, wherein the iron oxide layer is a mixed layer which comprises one or both of the metal oxides, selected from Al.sub.2O.sub.3 or TiO.sub.2, in a fraction of more than 0 to 20 wt %, based on the layer B.

6. The metallic effect pigment as claimed in claim 1, further comprising an outer layer C, which in turn envelops the coating B, more particularly an SiO.sub.2 layer 1 to 30 nm thick, which optionally may also penetrate the lower Fe.sub.2O.sub.3.

7. The metallic effect pigment as claimed in claim 1, wherein an organic or organic-inorganic surface modification has been applied to the layer B or to the layer C, if present.

8. A method for producing a metallic effect pigment as claimed in claim 1, comprising applying the SiO.sub.2 layer A wet-chemically via a sol-gel process to a pre-provided aluminum substrate platelet and subsequently applying the Fe.sub.2O.sub.3 layer B by means of wet-chemical precipitation of one or more iron(III) salts and subsequent calcining.

9. The method as claimed in claim 8, further comprising applying a further, outer layer C, which in turn envelops the coating B, more particularly an SiO.sub.2 layer 1 to 30 nm thick, which optionally may also penetrate the lower Fe.sub.2O.sub.3.

10. The method as claimed in claim 8, further comprising applying an organic or organic-inorganic surface modification to the layer B or to the layer C, if present.

11. A coloring paint, printing ink, liquid ink, plastic, glass, ceramic product, or preparation of decorative cosmetic, especially in nail varnishes, lip gloss, eyeshadow, lipsticks, shampoos and/or powders, comprising the metallic effect pigments of claim 1, where the metallic effect pigments is used alone or in a mixture with an organic and/or inorganic pigment.

Description

[0040] FIG. 1 shows the general layer construction of the metallic effect pigments of the invention (not to scale).

[0041] FIG. 2 shows the SEM section of a metallic effect pigment of the invention, namely the inventive pigment (construction of this pigment: substrate=Decomet (VMP aluminum platelet) with layer thickness ˜25 nm, thereon an SiO.sub.2 layer with ˜60 nm, and lastly an Fe.sub.2O.sub.3 layer with ˜45 nm, without a further coating, such as a further SiO.sub.2 coating, for example, and without surface modification).

[0042] The examples which follow serve as a further illustration of the present invention, without being confined thereto.

EXAMPLES

[0043] Inventive pigment=Decomet (VMP aluminum) as substrate, layer A=SiO.sub.2 with layer thickness in the inventive range, layer B=Fe.sub.2O.sub.3 with layer thickness in the inventive range.

Inventive Examples

[0044] (1) Inventive pigment+around 1.6% Al.sub.2O.sub.3 [0045] (2) Inventive pigment [0046] (3) Inventive pigment with around 6% TiO.sub.2 [0047] (4) Inventive pigment with around 1.6% Al.sub.2O.sub.3+SiO.sub.2 (layer C, arithmetic thickness 16.5 nm) [0048] (5) Inventive pigment with around 1.6% Al.sub.2O.sub.3+SiO.sub.2 (layer C, arithmetic thickness 26.5 nm)

Noninventive Examples

[0049] (6) Merck Iriodin 9602 with 4.5% yellow pigment Helio Beit UN 210 [0050] (7) Merck Iriodin 9602 [0051] (8) Alustar 10200 with 4% yellow pigment Helio Beit UN 210 [0052] (9) Alustar 10200 with 10% yellow pigment Helio Beit UN 210 [0053] (10) Pigment 21 YY (Zenexo GoldenShine, Schlenk Metallic Pigments GmbH) [0054] (11) Pigment 21YY with 1% Helio Beit Carbon Black (carbon black dispersion) [0055] (12) Pigment 21YY with 10% Iriodin 119 [0056] (13) Pigment 21YY with 20% Iriodin 119 [0057] (14) Pigment 21YY with 50% Iriodin 119 [0058] (15) Pigment 21YY with 1.5% TiO.sub.2

Production of Inventive Examples

[0059] First of all, Al platelets were coated with SiO.sub.2 by a sol-gel method using tetraethyl orthosilicate (TEOS) (cf., for example, WO 2015/014484 A1).

[0060] Subsequently a 2 L beaker is charged with the amount of suspension corresponding to an aluminum content of 15 g. The suspension is made up with mains water to 900 g.

[0061] At the start of the synthesis, slight acidification is carried out. This is followed by commencement of addition of the FeCl.sub.3 solution; the pH is kept constant by the addition of an alkaline solution, e.g., KOH, NaOH, Ca(OH).sub.2 or NH.sub.3. At the end of the synthesis the pH is raised with stirring. Subsequently, after sedimentation, the resulting pigment is separated off by filtration, dried, and subsequently calcined.

[0062] The table below reports the layer thicknesses and coloristic data for above inventive and noninventive examples:

TABLE-US-00001 Hiding power Hue angle Saturation ΔE45° % pigmentation Alman Designation of the examples No. (h.sub.uv) (S.sub.uv) (% pigmentation) for ΔE45° = 1 Index Gdiff Inventive Inventive range 50-65 0.2-0.3 ≤3 (7%) <7%  >26 <6  Inventive pigment 1 55-57 0.23-0.24 3.4 (4.2%), 5.1 33-34 4.0-5.0 Yes (with around 1.6% Al.sub.2O.sub.3) 0.06 (7.2%) Inventive pigment 2 54 0.26 0.2 (7%) 5.5 34 5.0 Yes Inventive pigment 3 61 0.20 2.4 (5%), 5.7 34 4.7-5.3 Yes (with around 6.0% TiO.sub.2) 0.2 (7%) Inventive pigment 4 56 0.26 2.4 (5%) 6.2 33.6 5.2 Yes (with around 1.6% Al.sub.2O.sub.3) + 16.5 nm (calculated) SiO.sub.2 (layer C) Inventive pigment 5 56 0.26 2.8 (5%) 6.7 33.2 5.3 Yes (with around 1.6% Al.sub.2O.sub.3) + 26.5 nm (calculated) SiO.sub.2 (layer C) Merck Iriodin 9602 + 6 71 0.26 8.4 (20%) — 22 3.8 No 4.5% yellow pigment Helio Beit UN 210 Merck Iriodin 9602 7 238-239 0.10-0.13 54 (4.2%), 31.8  27-31 5.0-6.5 No 35 (7.2%) Alustar 10200 + 8 71 0.48 1.6 (4%) — 28 5.4 No 4% yellow pigment Helio Beit UN 210 Alustar 10200 + 9 65 0.70 1.2 (4%) — 26 5.5 No 10% yellow pigment Helio Beit UN 210 21 YY (Zenexo GoldenShine) 10 62 0.92 1.8 (7%) 7.8 31 5.0 No 21 YY (Zenexo GoldenShine) + 11 63 0.89 2.2 (7%) — 31 5.2 No 1% Helio Beit Carbon Black 21 YY (Zenexo GoldenShine) + 12 63 0.83 3.1 (7%) 9.1 29 5.1 No Merck Iriodin 119 10% 21 YY (Zenexo GoldenShine) + 13 63 0.75 4.4 (7%) 9.6 27 5.0 No Merck Iriodin 119 20% 21 YY (Zenexo GoldenShine) + 14 62 0.50 10.2 (7%) 13.2  22 4.7 No Merck Iriodin 119 50% 21 YY (Zenexo GoldenShine) + 15 63 0.89 2.4 (7%) — 28 5.1 No TiO.sub.2 1.5% The SEM micrographs were each recorded with a Zeiss Auriga 40 scanning electron microscope. The coloristic data were produced by measuring knife-applied coatings of the pigments (unless otherwise remarked, with a pigmentation of 7% in a solvent-based nitrocellulose/polycyclohexanone/polyacrylic varnish, SC ~10%) on a DIN A5 black/white card from TQC using a 38 μm wire-wound doctor knife on an automatic film-drawing apparatus from Zehntner. The coloristic data were measured using the Byk-mac I from Byk.