Anisotropic Printing Coating Particles for Anti-Counterfeiting

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Solution Overview

Problem

Current methods for producing Janus particles with multiple surface areas of different physical properties are inefficient, costly, and difficult to scale up for industrial use, often resulting in unreliable and time-consuming processes with limited reproducibility, and challenges in achieving defined alignment for applications like anti-counterfeiting measures.

Innovation Solution

A combination of printing and coating processes is used to create anisotropic particles with separate surface areas, where one material is applied via continuous ink jet, screen, or 3D printing, and another via contactless coating methods like PVD or CVD, allowing for scalable and reproducible production of particles with distinct physical properties.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If phase separation method is used to produce Janus particles, then two different surface areas with different physical properties can be formed, but reliable industrial-scale production is difficult and two separate particles may be produced instead of one Janus particle

Engineering Contradiction:
Improveformation of Janus particle structureVSAvoidindustrial-scale production reliability
Core Design Contradiction:
Manufacturing precisionVSReliability

Solution Approach 1:

The invention divides the particle production process into two independent stages: first forming a core particle with desired properties, then coating it with a different material. This segmentation allows each stage to be optimized separately, ensuring reliable Janus particle formation at industrial scale while maintaining precise control over surface area properties.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The core particle is prepared in advance with specific physical properties (such as magnetic properties for alignment), then subsequently coated with a different material. This preliminary action ensures that the core properties are established before coating, preventing the formation of separate particles and ensuring reliable Janus particle production.

Inventive Principle:
Principle #10Preliminary action

2Manufacturing precision

If self-orientation method is used to produce Janus particles, then alternating layers of different materials can form through polymer self-organization, but particle size is limited by selected substances

Engineering Contradiction:
Improvelayer formation precisionVSAvoidparticle size range
Core Design Contradiction:
Manufacturing precisionVSAdaptability or versatility

Solution Approach 1:

The invention changes the controlling parameters from polymer molecular weight and composition (which limit size) to core particle size and coating thickness. This allows particle size to be independently adjusted across a wide range by selecting different core materials and coating conditions, while maintaining precise layer formation through controlled coating processes.

Inventive Principle:
Principle #35Parameter changes

3Manufacturing precision

If masking method is used to produce Janus particles, then a particle with first property can be coated on opposite side to produce second property, but coating agent does not connect several particles and particles fail to separate or coating detaches

Engineering Contradiction:
Improvesurface area coating precisionVSAvoidcoating adhesion strength
Core Design Contradiction:
Manufacturing precisionVSStrength

Solution Approach 1:

The invention introduces a binder material as an intermediary that connects multiple particles together while also serving as the coating material. This binder forms a continuous matrix that embeds the particles, ensuring strong adhesion and preventing coating detachment, while still allowing the particles to maintain their distinct surface properties.

Inventive Principle:
Principle #24Intermediary (Mediator)

4Measurement precision

If magnetic separation is used to select good material, then particles with magnetic property can be selected, but separation is complex requiring two passes and good material selection is limited

Engineering Contradiction:
Improvematerial property selection accuracyVSAvoidseparation process complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The invention makes the core particle itself magnetic rather than using magnetic separation to select non-magnetic particles. This allows a single magnetic separation pass to both select the particles and align them with desired properties, eliminating the need for two passes and reducing process complexity while maintaining high selection accuracy.

Inventive Principle:
Principle #6Universality (Multi-functionality)

5Manufacturing precision

If current Janus particle production methods are used, then particles can be produced for research applications, but production is time-consuming and costly with limited scalability for industrial use

Engineering Contradiction:
Improveparticle property definitionVSAvoidindustrial-scale production capacity
Core Design Contradiction:
Manufacturing precisionVSProductivity

Solution Approach 1:

The invention replaces complex multi-step mechanical processes (masking, multiple coatings, careful handling) with a simplified sequential process of core formation followed by coating in a binder matrix. This substitution enables continuous production methods and industrial-scale manufacturing while maintaining precise control over particle properties.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

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

This approach enables the efficient and cost-effective production of anisotropic particles with defined physical properties, suitable for industrial-scale applications, such as anti-counterfeiting measures, by ensuring reliable and scalable production of particles with aligned properties.

Implementation Method 1

at least one printing material is applied by continuous ink jet printing, ink jet printing, screen printing or 3D printing

Methodology Applied
Scientific EffectInk jet printing:

Implementation Method 2

The at least one coating material is applied by a contactless coating method, with PVD (physical vapor deposition) methods, CVD (chemical vapor deposition) methods or spray coating methods

Methodology Applied
Scientific EffectPhysical vapor deposition: Physical Vapour Deposition

Implementation Method 3

The at least one coating material is applied by a contactless coating method, with PVD (physical vapor deposition) methods, CVD (chemical vapor deposition) methods or spray coating methods

Methodology Applied
Scientific EffectChemical vapor deposition: Chemical Vapour Deposition

Implementation Method 4

The at least one coating material is applied by a contactless coating method, with PVD (physical vapor deposition) methods, CVD (chemical vapor deposition) methods or spray coating methods

Methodology Applied
Scientific EffectSpray coating: Spray

Data Source

PatentEP3501839B1Particles for counterfeit prevention
Publication Date: 2021.08.11 GIESECKE & DEVRIENT CURRENCY TECHNOLOGY GMBH
  • EP3501839B1 patent drawingFigure 1~3
  • EP3501839B1 patent drawingFigure 4(a)~7
  • EP3501839B1 patent drawingFigure 8~12

AI summary

The invention relates to an anisotropic printing/coating particle (14) for use in a printing ink (10) or a varnish for anti-counterfeiting purposes, which has at least two separate surface areas (14A, 14B) with different physical properties, wherein at least one of said surface areas (14A, 14B) is formed by a coating material and at least one component of the particle is formed by a printing material, in particular a printing ink. In a method for producing such anisotropic printing/coating particles, at least one printing material (112) is directly or indirectly combined by a printing process and at least one coating material (114) is directly or indirectly combined by a coating process to produce the at least two separate surface areas with different physical properties.The printing-produced layers (18-1), (18-2) are coated (18-3) with a blue reflective coating material using a coating process. The physical properties may include: surface tension; specific gravity; color of the surface areas, in particular the color spectrum of the surface areas in the UV, VIS and/or IR range, where the term color includes both non-color-variable and color-variable properties, for example, color-shifting or otherwise optically variable designs; magnetic properties; luminescence properties; electrical conductivity; polarization properties; gloss and reflectivity.