Abstract: The present invention provides a UV-Vis radiation curable security ink for producing a security feature for securing value documents, wherein said security feature exhibits a blue color upon viewing in transmitted light and a metallic yellow color upon viewing in incident light. The UV-Vis radiation curable security ink comprises a cationically curable or a hybrid curable ink vehicle, and silver nanoplatelets bearing a surface stabilizing agent of general formula (I) wherein the residue RA is a C2-C4alkyl group substituted with a hydroxy group; the residue RB is selected from a C1-C4alkyl group, and a C2-C4alkyl group substituted with a hydroxy group; and Cat+ is an ammonium cation of general formula +NH2RCRD, wherein the residue RC is a C2-C4alkyl group substituted with a hydroxy group; and the residue RD is selected from a C1-C4alkyl group, and a C2-C4alkyl group substituted with a hydroxy group.

Abstract: The present invention provides a UV-Vis radiation curable security ink for producing a security feature for securing value documents, wherein said security feature exhibits a blue color upon viewing in transmitted light and a metallic yellow color upon viewing in incident light. The UV-Vis radiation curable security ink comprises a cationically curable or a hybrid curable ink vehicle, and silver nanoplatelets bearing a surface stabilizing agent of general formula (I) wherein the residue RA is a C2-C4alkyl group substituted with a hydroxy group; the residue RB is selected from a C1-C4 alkyl group, and a C2-C4alkyl group substituted with a hydroxy group; and Cat+ is a cation selected from the group consisting of Na+, K+, Cs+ and Rb+.

Abstract: The present invention relates to coating compositions, comprising i) single or mixed metal oxide nanoparticles, wherein the volume average diameter (Dv50) of the metal oxide nanoparticles is in the range of 1 to 20 nm; the nanoparticles comprise at least one volatile surface-modifying compound selected from alcohols, ?-diketones, or salts thereof; carboxylic acids and ?-ketoesters and Ge mixtures thereof, wherein the total amount of volatile surface-modifying compounds is at least 5% by weight, preferably at least 10% by weight based on the amount of metal oxide nano-particles, and ii) a solvent, coatings obtained therefrom and the use of the comositions for coating surface relief micro- and nanostructures (e.g. holograms), manufacturing of optical waveguides, solar panels, light outcoupling layers for display and lighting devices and anti-reflection coatings.

Abstract: The present invention relates to compositions, comprising platelet-shaped transition metal particles, wherein the number mean diameter of the platelet-shaped transition metal particles, present in the composition, is in the range of 15 nm to 1000 nm and the number mean thickness of the platelet-shaped transition metal particles, present in the composition, is in the range of 2 to 40 nm, the transition metal is selected from silver, copper, gold and palladium and the platelet-shaped transition metal particles bear a surface modifying agent of formula A-(CHR9)r—R10 (V), wherein if r is 1, A is a C1-C25alkyl group substituted with one, or more fluorine atoms; a C2-C25alkenyl substituted with one, or more fluorine atoms; a C2-C25alkynyl group substituted with one, or more fluorine atoms; a C3-C20cycloalkyl group substituted with one, or more fluorine atoms; or a C6-C24aryl group substituted with one, or more fluorine atoms, CF3 or —O—CF3 groups; if r is 0, A is a C6-C24aryl group substituted with one, or more flu

Abstract: The present invention provides a process for manufacturing a security feature for securing a value document, wherein said security feature exhibits a blue color upon viewing in transmitted light and a metallic yellow color upon viewing in Incident light. The manufacturing process comprises the following steps: a) printing a specific UV-Vis radiation curable ink on a transparent or partially transparent region of a substrate of a value document; b) heating the ink layer obtained at step a) at a temperature of about 55° C. to about 100° C. for at least one second so that the ink layer exhibits a metallic yellow color upon viewing in incident light; and c) UV-Vis curing the ink layer obtained at step b) to form the security feature.

Abstract: The present invention relates to metal oxide nanoparticles, a method for their production, a coating, or printing composition, comprising the metal oxide nanoparticles and the use of the composition for coating of surface relief micro- and nanostructures (e.g. holograms), manufacturing of optical waveguides, solar panels, light outcoupling layers for display and lighting devices and anti-reflection coatings. Holograms are bright and visible from any angle, when coated, or printed with the composition, comprising the metal oxide nanoparticles.

Abstract: The present invention relates to compositions, comprising silver nanoplatelets, wherein the number mean diameter of the silver nanoplatelets, present in the composition, is in the range of 50 to 150 nm with standard deviation being less than 60% and the number mean thickness of the silver nanoplatelets, present in the composition, is in the range of 5 to 30 nm with standard deviation being less than 50%, wherein the mean aspect ratio of the silver nanoplatelets is higher than 2.0 and the highest wavelength absorption maximum of the population of all silver nanoplatelets in the composition being within the range of 560 to 800 nm. A coating, comprising the composition, shows a blue color in transmission and a metallic yellow color in reflection.

Abstract: The present invention relates to compositions, comprising silver nanoplatelets, wherein the mean diameter of the silver nanoplatelets, present in the composition, is in the range of 20 to 70 nm with standard deviation being less than 50% and the mean thickness of the silver nanoplatelets, present in the composition, is in the range of 5 to 30 nm with standard deviation being less than 50%, wherein the mean aspect ratio of the silver nanoplatelets is higher than 1.5, a process for its production, printing inks containing the compositions and their use in security products. The highest wavelength absorption maximum of the population of all silver nanoplatelets in the composition being within the range of 450 to 550 nm. A coating, comprising the composition, shows a red, or magenta color in transmission and a greenish-metallic color in reflection.