Assemblies and processes for producing optical effect layers comprising oriented non-spherical oblate magnetic or magnetizable pigment particles
AssigneeSicpa Holding SA
InventorsCédric Amerasinghe, Edgar Mueller, Evgeny Loginov, Mathieu Schmid, Claude-Alain Despland
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Abstract
The present invention relates to the field of optical effect layers (OEL) comprising magnetically oriented non-spherical oblate magnetic or magnetizable pigment particles on a substrate, spinneable magnetic assemblies and processes for producing said optical effect layers (OEL). In particular, the present invention relates to spinneable magnetic assemblies and processes for producing said OELs as anti-counterfeit means on security documents or security articles or for decorative purposes.
Claims17
An optical effect layer (OEL) comprising a radiation cured coating composition comprising non-spherical oblate magnetic or magnetizable pigment particles, said non-spherical oblate magnetic or magnetizable pigment particles being oriented according to an orientation pattern,
- wherein the orientation pattern is circularly symmetric around a center of rotation,
- wherein the non-spherical oblate magnetic or magnetizable pigment particles at at least two, distinct locations xi along any selected diameter of the OEL have an average zenithal deflection angle φ′ at location xi and an average azimuth angle θ with respect to the selected diameter at the same location xi that satisfy the condition |(φ′ sin (θ)|≥10°,
- and said optical effect layer providing an optical impression of at least one circularly moving spot or at least one spot having a tail section rotating around said center of rotation upon tilting said OEL.
Dependencies are inferred from the claim text.