Processes for hardening in the field of layers with optical effects produced by magnetic field generating devices that generate concave field lines and layers with optical effects produced by such processes

摘要

A process for producing a layer with an optical effect (OEL) on a substrate (S), said process comprising the steps of: a) applying on the substrate a coating composition (CC) comprising a plurality of magnetic or magnetizable pigment particles to form a coating layer (C, C1), said coating layer being in a first state, b) b1) exposing the coating layer to the magnetic field of a magnetic field generating device (MD, MD1), said said layer being located magnetic field generating device on the side of the coating layer thus orienting the plurality of magnetic or magnetizable pigment particles, and b2) simultaneously or partially harden simultaneously through the substrate of the coating layer to a second state for fix the magnetic or magnetizable pigment particles in their adopted positions and orientations, said hardening being performed by irradiation with n a source of UV-Vis (L) radiation located on the side of the substrate, where the substrate is transparent at one or more wavelengths of the emission spectrum of the irradiation source in the range of 200 nm to 500 nm, and wherein the plurality of magnetic or magnetizable pigment particles is oriented to follow a concave curvature when viewed from the side carrying the OEL.