Effect optically variable pigments

Such types of effect pigments can be used for several applications and are on the market as so-called optically variable pigments (OVP). They have found broad application, especially in preventing counterfeiting of important documents such as banknotes, stock certificates, visas, passports, or car licenses. When incorporated into security inks and printed on bank notes and other documents of value, the pigments... 

A CVD-process is known to produce iron-oxide-coated aluminum flakes which form high brilliance colored aluminum pigments with highly interesting interference effects [5.174]. Some of the very new optically variable pigments consist of multilayer flake pigments with a metallic core to obtain metaUic reflection and coverage ]5.175]. 

Uses Pigment for water- and solv.-based paints/coatings, UV-curing paints, powd. coatings, cosmetics, plastics Features Optically variable effect color reflection with copper-red-green color, deep gloss, high brilliance stable to 330 C Properties Colorless, yish. wh. powd. (platelets) dens. 1.3 g/cm bulk dens. 400 g/l surf, area = 1.0 nf/g pH = 7 (10% aq. susp.) conduct. 32 S (10% aq. susp.)... 

---