Magnetic Orientation of Non-Spherical Pigment Particles for Loop-Shaped Optical Effects

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Solution Overview

Problem

Existing security features, particularly optical effect layers (OELs), struggle to produce high-quality, dynamic loop-shaped effects that are difficult to counterfeit and can be easily verified regardless of document orientation, and are challenging to produce on a mass scale with available equipment.

Innovation Solution

A process involving a radiation curable coating composition with non-spherical magnetic or magnetizable pigment particles is applied to a substrate, exposed to a magnetic field generated by a loop-shaped dipole magnet or combination of magnets, and partially cured to create an optical effect layer that appears as loop-shaped bodies whose size varies upon tilting, using a magnetic assembly and field generating device to orient particles effectively.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If conventional permanent magnet arrangements are used to orient pigment particles, then magnetic orientation can be achieved, but the production of high-quality dynamic loop-shaped effects is difficult and equipment is complex

Engineering Contradiction:

Improvequality of loop-shaped effectVSAvoidcomplexity of magnetic assembly

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The magnetic assembly is segmented into multiple independent dipole magnets arranged in a loop configuration, each contributing to the overall magnetic field pattern. This segmentation allows precise control of particle orientation to form loop-shaped effects while distributing the complexity across modular components rather than requiring a single complex magnet arrangement.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The dipole magnets are arranged in a loop (curved) configuration rather than a linear arrangement, creating a magnetic field pattern that naturally guides pigment particles into loop-shaped orientations. This curved geometry directly produces the desired loop-shaped visual effect while simplifying the overall magnetic assembly design.

Inventive Principle:

Principle #14Spheroidality (Curvature)

2Productivity

If mass production is implemented with existing equipment, then productivity increases, but the ability to produce high-quality dynamic loop-shaped effects deteriorates

Engineering Contradiction:

Improvemass production capabilityVSAvoidquality of optical effect

Core Design Contradiction:

ProductivityVSManufacturing precision

Solution Approach 1:

The coating composition is prepared in advance with non-spherical magnetic pigment particles already dispersed in the radiation-curable matrix. This preliminary preparation ensures that during mass production, the particles are pre-positioned and will automatically orient into the desired loop patterns when exposed to the magnetic field during the curing process, maintaining high quality while enabling efficient production.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent replaces complex mechanical particle orientation systems with a magnetic field-based orientation system. The magnetic field automatically orients the particles during the curing process without requiring complex mechanical manipulation equipment, enabling both mass production and high-quality loop-shaped effects.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Reliability

If radiation curable coating composition is used with magnetic particles, then particle orientation and curing can be achieved, but the process complexity increases

Engineering Contradiction:

Improveparticle orientation controlVSAvoidprocess complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent merges the particle orientation function and the curing function into a single integrated process step. The radiation-curable coating composition is applied, and then both particle orientation (via magnetic field) and curing (via radiation) are achieved in sequence without requiring separate equipment or processes, simplifying the overall system while maintaining reliable particle orientation control.

Inventive Principle:

Principle #5Merging (Combining)

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 resulting optical effect layer provides a clear, eye-catching dynamic loop-shaped effect that is resistant to counterfeiting and can be easily verified, offering enhanced security against fraud and illegal reproduction.

Implementation Method 1

exposing the radiation curable coating composition to a magnetic field generated by a loop-shaped dipole magnet or combination of magnets

Methodology Applied

Scientific EffectMagnetic field: Magnetic Field

Implementation Method 2

radiation curable coating composition with non-spherical magnetic or magnetizable pigment particles

Methodology Applied

Scientific EffectMagnetism: Magnetism

Implementation Method 3

radiation curable coating composition

Methodology Applied

Scientific EffectPhotopolymerisation: Photopolymerisation

Data Source

PatentUS10906066B2Appartuses and processes for producing optical effect layers comprising oriented non-spherical magnetic or magnetizable pigment particles

Publication Date: 2021.02.02 SICPA HOLDING SA

AI summary

The present invention relates to the field of magnetic assemblies and processes for producing optical effect layers (OEL) comprising magnetically oriented non-spherical magnetic or magnetizable pigment particles on a substrate. In particular, the present invention relates magnetic assemblies and processes for producing said OELs as anti-counterfeit means on security documents or security articles or for decorative purposes.