Optical Effect Layers With Magnetic Pigment Indicia at High Speed
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Solution Overview
Problem
Current methods for producing optical effect layers (OELs) with magnetically oriented non-spherical magnetic or magnetizable pigment particles are not suitable for creating customized, variable indicia on a large industrial scale with high production speed and reliability.
Innovation Solution
A method involving the application of a radically radiation curable coating composition containing non-spherical magnetic or magnetizable pigment particles, followed by a top coating composition applied in a wet-on-wet state using contactless fluid microdispensing technologies like inkjet printing. This method allows for the production of OELs with multiple areas oriented differently, enabling the creation of customized indicia without requiring specialized curing units or frequent modification of magnetic assemblies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional methods with specialized curing units and magnetic assemblies are used, then magnetic orientation precision is improved, but device complexity and production flexibility deteriorate
Solution Approach 1:
The patent extracts the magnetic orientation function from complex specialized assemblies and curing units, using instead a simple handheld magnet applied during the wet coating stage. This separates the magnetic orientation step from complex equipment requirements, achieving precise particle alignment without specialized magnetic assemblies or curing units.
Solution Approach 2:
The patent replaces complex mechanical magnetic assemblies with a simple magnetic field application approach. Instead of using elaborate magnetic devices, the invention uses a straightforward magnetic field applied to the wet coating, substituting mechanical complexity with a simpler field-based solution that achieves the same orientation effect.
2Adaptability or versatility
If customized variable indicia are produced using conventional methods, then manufacturing versatility is improved, but production speed and reliability deteriorate
Solution Approach 1:
The patent applies the magnetic field during the wet coating stage, before the coating cures. This preliminary action allows the magnetic particles to be oriented while the coating is still fluid and responsive, enabling customized indicia to be created in the same production cycle without requiring separate customization steps, thus maintaining both versatility and high production speed.
Solution Approach 2:
The patent utilizes the dynamic state of the wet coating, where particles can move and reposition in response to magnetic fields. This dynamic approach allows flexible creation of variable indicia during production, enabling customization without slowing down the production line or requiring frequent equipment modifications.
3Object-affected harmful factors
If protective varnish is applied as a continuous layer on top of magnetically induced image, then protection against soil and moisture is improved, but the ability to produce customized indicia deteriorates
Solution Approach 1:
The patent merges the protective coating application with the magnetic orientation step by applying both to the wet coating simultaneously. The protective varnish is incorporated into the same wet-on-wet process, allowing the magnetic particles to be oriented and the protective layer to be applied in one integrated step, thus maintaining customization capability while providing protection.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The method enables the production of eye-catching OELs with customized indicia, suitable for security documents and decorative elements, while ensuring high production speed, reliability, and versatility, without the need for complex equipment or frequent assembly modifications.
Implementation Method 1
a) of applying on a substrate surface a radically radiation curable coating composition comprising non-spherical magnetic or magnetizable pigment particles... c) of at least partially curing the coating layer and the indicia below said one or more indicia
Implementation Method 2
Magnetic or magnetizable pigment particles in printing inks or coatings allow for the production of magnetically induced images, designs and/or patterns through the application of a correspondingly structured magnetic field, inducing a local orientation of the magnetic or magnetizable pigment particles in the not yet hardened (i.e. wet) coating
Data Source
AI summary
The invention relates to the field of the protection of security documents such as for example banknotes and identity documents against counterfeit and illegal reproduction. In particular, the present invention provides methods for producing optical effect layers (OELs) exhibiting one or more indicia (×30) on a substrate (×20), said method comprising a step of exposing a coating layer (×10) comprising non-spherical magnetic or magnetizable pigment particles to a magnetic field of a magnetic-field generating device so as to orient at least a part of the magnetic or magnetizable pigment particles; a step of applying a top coating composition on top of the coating layer (×10) and in the form of one or more indicia (×30), and a step of at least partially curing the coating layer (×10) and the one or more indicia (×30) with a curing unit (×50).