METHOD FOR MANUFACTURING SECURITY ELEMENTS AND HOLOGRAMS

摘要

The present invention relates to a method for forming a surface relief microstructure, especially an optically variable image (an optically variable device) on a transparent or translucent substrate and a product obtainable using the method. A further aspect of the invention is the use for the prevention of counterfeit or reproduction of a document of value and a method of forming a coating showing an angle dependent color change.

主权项

1: A method for forming a surface relief microstructure, especially an optically variable image on a substrate comprising the steps of:
A) applying a curable composition to at least a portion of a front side of the substrate wherein the substrate is transparent or translucent, and wherein the curable composition comprises:
a1) an ethylenically unsaturated resin, a monomer or a mixture thereof;a2) a photoinitiator selected from the group consisting of a monoacylphosphine oxide compound and a bisacylphosphine oxide compound; anda3) a metal pigment which is in the form of platelet shaped transition metal particles having a longest dimension of edge length of from 5 nm to 1000 nm, and a thickness of from 1 nm to 100 nm, wherein the metal is Ag; B) contacting at least a portion of the curable composition with a surface relief microstructure; C) curing the composition with at least one UV lamp, which is arranged on a backside of the transparent or translucent substrate.