Copper-based metal flakes, in particular comprising zinc and method for production thereof
The present invention relates to highly lustrous gold-colored metal effect pigments comprising a copper-based alloy and additional metallic alloy components, preferably zinc, and which are produced by means of stripping and comminuting metal films deposited in vacuo.
1. Lustrous copper-based metal flakes that contain, in addition to 70-98 wt % copper, at least one additional metallic alloy component comprising 2% to up to 30 wt % zinc and are produced via vacuum evaporating of the separate components and wherein each component of the alloy is evaporated separately, deposition of alloy metal films onto a carrier sheet, stripping of the films from the carrier sheet and subsequent comminuting of the films wherein the flakes have plane-parallel surfaces and a thickness of between 20 and 60 nm.
2. Lustrous copper-based metal flakes according to claim 1 , characterized in that the flakes contain silicon as an additional alloy component.
3. Lustrous copper-based metal flakes according to claim 1 , characterized in that the flake-shaped effect pigment has a thickness between 10 and 100 nm.
4. Lustrous, copper-based metal flakes according to claim 1 , characterized in that the surface of the pigment particles is coated with an anticorrosive layer.
5. Lustrous copper-based metal flakes according to claim 4 , characterized in that the anticorrosive layer contains aluminum oxide, silicon oxide, phosphate, phosphoric acid, phosphoric ester, phosphinic acid, silanes, organically modified silicates, titanates, zirconates or methacrylate-based polymer layers or combinations of these compounds.
6. A method for producing lustrous, copper-based metal flakes according to claim 1 wherein in the at least one additional alloy component is zinc with the following process steps:
a) optionally applying a release coat on a carrier sheet;
b) applying of a metal film onto the release coat or the carrier sheet;
c) stripping of the metal film; and
d) comminuting to pigment particles.
7. A method for producing lustrous copper-based metal flakes according to claim 1 with the following process steps:
a) applying of a metal film onto a carrier sheet;
b) dissolving of the carrier sheet; and
c) comminuting of the metal film to pigment particles.
8. A method according to claim 6 , characterized in that applying of the metal film takes place by separate evaporation of the alloy components.
9. A method according to claim 6 , characterized in that applying of the metal film takes place through separate evaporation of an alloy and one or more additional components.
10. A method according to claim 6 , characterized in that applying of the metal film takes place through electron beam, resistance heating, or radiation heating.
11. A method according to claim 6 , characterized in that applying of the metal film takes places through flash evaporation, simultaneous evaporation, or jumping beam evaporation.