Processes for producing optical effects layers
AssigneeSicpa Holding SA
InventorsMathieu Schmid, Evgeny Loginov, Claude-Alain Despland
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Abstract
The present invention relates to the field of and processes and printing apparatuses for producing optical effect layers (OEL) comprising magnetically oriented platelet-shaped magnetic or magnetizable pigment particles on a substrate. In particular, the present invention relates to processes using printing apparatuses comprising a first magnetic-field-generating device mounted on a transferring device (TD) and a static second magnetic-field-generating device for producing said OELs as anti-counterfeit means on security documents or security articles or for decorative purposes.
Claims13
A process for producing an optical effect layer on a substrate, said process comprising the steps of:
- a) applying onto a substrate surface a coating composition comprising platelet-shaped magnetic or magnetizable pigment particles so as to form a coating layer on said substrate, said coating composition being in a first state,
- b) placing the substrate carrying the coating layer on a first magnetic-field-generating device providing a first magnetic field vector component, said first magnetic-field-generating device being mounted on a transferring device thereby subjecting the platelet-shaped magnetic or magnetisable pigment particles to said first magnetic field vector component,
- concomitantly moving said substrate carrying the coating layer and said first magnetic-field-generating device in the vicinity of a static second magnetic-field-generating device, said second magnetic-field-generating device providing a second magnetic field vector component
- thereby subjecting the platelet-shaped magnetic or magnetisable pigment particles to a time-dependent resultant magnetic field formed by the first and second magnetic field vector components so as to bi-axially orient at least a part of the platelet-shaped magnetic or magnetizable pigment particles, and
- c) hardening the coating composition to a second state so as to fix the platelet-shaped magnetic or magnetizable pigment particles in their adopted positions and orientations.
Dependencies are inferred from the claim text.