Bismuth vanadate pigments
A bismuth vanadate pigment is provided which pigment is doped with a combination of Mg, Al and P and optionally an element E, wherein the molar ratios of the Bi, V, Mg, Al, P and E correspond to a formula Bi Mg a Al b E c V d P e O f (I) wherein E is selected from the group consisting of Be, Ca, Sr, Ba, Zr, Mo, Ce and a combination thereof; 0.001≦a≦0.2; 0.001≦b≦0.2; 0≦c≦1.7; 0.5≦d≦2.3; 0.001≦e≦0.5; and f denotes the number of oxygen atoms for satisfying the valence requirements of the cations. The pigment may be used as colorant in various applications, especially in coloring high molecular weight organic material, for example, coating compositions, paints, printing inks, liquid inks, plastics, films, fibers, or glazes for ceramics or glass.
1. A bismuth vanadate pigment of formula
Bi Mg a Al b E c V d P e O f (I)
wherein E is selected from the group consisting of Ca, Sr, Ba, Zr, Mo, Ce and a combination thereof;
0.001≦a≦0.2;
0.001≦b≦0.2;
0≦c≦1.7;
0.5≦d≦2.3;
0.001≦e≦0.5; and
f denotes the number of oxygen atoms for satisfying the valence requirements of the cations.
2. The bismuth vanadate pigment according to claim 1 , wherein 0.001≦a≦0.15; 0.001≦b≦0.15; 0≦c≦1.5; 0.8≦d≦2.3; and 0.01≦e≦0.4.
3. The bismuth vanadate pigment according to claim 1 , wherein
E is selected from the group consisting of Ca, Zr, Mo, Ce and a combination thereof; and
0.001≦c≦1.5.
4. The bismuth vanadate pigment according to claim 1 , wherein
E is selected from the group consisting of Ca, Zr, Mo and a combination thereof;
0.001≦c≦0.5 and 0.8≦d≦1.5.
5. The pigment according to claim 1 , wherein
E is Ca and/or Zr; and
0.001≦c≦0.5.
6. The pigment according to claim 1 , wherein
E is Ca and/or Zr; and
0.01≦c≦0.5.
7. The pigment according to claim 1 , wherein
E is Zr and Mo;
0.001≦a≦0.15; 0.001≦b≦0.15; 0.01≦c≦0.5; 0.8≦d≦1.5; and 0.01≦e≦0.4.
8. The pigment according to claim 1 , wherein
E is Ce or a combination of Zr and Ce or a combination of Ca and Ce;
0.001≦a≦0.15; 0.001≦b≦0.15; 0.01≦c≦1.5; 0.8≦d≦2.3; and 0.01≦e≦0.4.
9. The pigment according to claim 1 , wherein
E is a combination of Ca, Zr and Ce;
0.001≦a≦0.15; 0.001≦b≦0.15; 0.01≦c≦1.5; 0.8≦d≦2.3; and 0.01≦e≦0.4.
10. The pigment according to claim 1 , wherein
E is a combination of Ca, Zr and Mo;
0.001≦a≦0.15; 0.001≦b≦0.15; 0.01≦c≦0.5; 0.8 5≦d≦1.5; and 0.01≦e≦0.4.
11. The pigment according to claim 1 , wherein c is 0;
0.001≦a≦0.15; 0.001≦b≦0.15; 0.8≦d≦1.5; and 0.01≦e≦0.4.
12. The pigment according to claim 1 , wherein vanadium is present as V(V) and V(IV) in a molar ratio of from 1:0.01 to 1:0.3.
13. A process of manufacturing the bismuth vanadate pigment of formula (I) as defined in claim 1 , which process comprises the steps of
a) treating an alkaline vanadate solution with an acidic bismuth salt solution in the presence of soluble salts of Mg, Al, and optionally of E and/or V(IV), and soluble phosphates in a pH range of from 0.1 to 10 to form a precipitate,
b) calcining the precipitate, and
c) grinding to form pigment particles.
14. A coating composition, a paint, a printing ink, a liquid ink, plastics, a film, a fiber, a glaze for ceramics or glass, which is colored with the pigment as defined in claim 1 .
15. A process for coloring a coating compositions, a paint, a printing ink, a liquid ink, plastics, a film, a fiber, a glaze for ceramics or glass, which process comprises adding thereto the pigment as defined in claim 1 .
16. The pigment according to claim 1 , wherein 0.001≦b≦0.15.
17. The pigment according to claim 1 , wherein 0.005≦b≦0.12.
18. The pigment according to claim 1 , wherein 0.005≦a≦0.12; 0.005≦b≦0.12; 0.01≦c≦1.5; 0.85≦d≦2.2; and 0.01≦e≦0.4.
19. The pigment according to claim 1 , wherein
E is Ca and Zr; and
0.001≦c≦0.5.