Rare-Earth Ink Composition for Anti-Counterfeiting

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Solution Overview

Problem

Current anti-counterfeiting techniques for printed products, such as those using fluorescent ink or temperature-sensitive color changing ink, have become obsolete due to advances in counterfeiting methods, necessitating a more advanced and effective method for authenticity determination and security marking that does not compromise the appearance or design of the products.

Innovation Solution

An ink composition containing rare-earth complexes with specific trivalent rare-earth ions and organic ligands, which emits fluorescence under non-visible light and changes emitted light color with heat, allowing for authenticity determination through frictional heat generated by rubbing, providing high authenticity and anti-counterfeiting properties.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If fluorescent ink or temperature-sensitive color changing ink is used for anti-counterfeiting printing, then the printed product has security marking capability, but the technique becomes obsolete due to widespread counterfeiting methods

Engineering Contradiction:
Improveanti-counterfeiting effectivenessVSAvoidresistance to counterfeiting techniques
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent changes the physical and chemical parameters of the ink by incorporating multiple rare-earth metal complexes with different emission characteristics. The ink composition includes Eu³⁺, Tb³⁺, and Dy³⁺ complexes that exhibit different fluorescence emissions and temperature-dependent color changes, creating a multi-parameter security system that is difficult to counterfeit

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent uses a composite ink formulation containing multiple rare-earth metal complexes coordinated with different organic ligands (β-diketone, carboxylic acid, phosphine oxide, and nitrogen-containing aromatic heterocyclic ligands). This composite material approach creates synergistic effects where the combination of multiple emissive species provides enhanced security verification capabilities

Inventive Principle:
Principle #40Composite materials

2Reliability

If security marking is applied to printed products, then authenticity determination capability is improved, but the appearance and design of the product may be compromised

Engineering Contradiction:
Improveauthenticity verification capabilityVSAvoidproduct appearance and design
Core Design Contradiction:
ReliabilityVSShape

Solution Approach 1:

The security marking ink is applied locally to specific regions of the printed product rather than covering the entire surface. The ink can be applied to security threads, watermarks, or specific design elements, allowing the security function to be integrated into the product design without compromising the overall appearance

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The rare-earth metal complexes exhibit temperature-dependent color changes that can be observed under appropriate excitation. This allows the security marking to be invisible or minimal under normal conditions but becomes visible and verifiable when subjected to controlled thermal or optical stimulation, thus preserving the product's aesthetic appearance

Inventive Principle:
Principle #32Color changes

3Ease of manufacture

If conventional fluorescent or temperature-sensitive ink is used, then the anti-counterfeiting method is simple to implement, but the method is easily counterfeited due to availability of light-emitting substances

Engineering Contradiction:
Improvesimplicity of implementationVSAvoidsecurity against counterfeiting
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The patent employs multiple rare-earth metal complexes with distinct emission wavelengths and temperature-dependent behavior. The specific combination of Eu³⁺ (red emission), Tb³⁺ (green emission), and Dy³⁺ (yellow emission) complexes creates a multi-dimensional verification system that maintains manufacturing simplicity while dramatically increasing counterfeiting difficulty

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The organic ligands (β-diketone, carboxylic acid, phosphine oxide, and nitrogen-containing aromatic heterocyclic ligands) serve as intermediaries that coordinate the rare-earth metal ions and modulate their optical and thermal properties. These ligand complexes act as mediators that enable the rare-earth metals to exhibit enhanced and tunable security characteristics

Inventive Principle:
Principle #24Intermediary (Mediator)

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 ink composition effectively changes light emission characteristics with temperature, enabling reliable authenticity verification and enhanced security marking without damaging the product's appearance, and is applicable across various printed products.

Implementation Method 1

emit fluorescence by irradiation of constant wavelength light other than visible light

Methodology Applied
Scientific EffectFluorescence: Fluorescence

Implementation Method 2

cause a change in emitted light color by heat

Methodology Applied
Scientific EffectThermochromism: Thermochromism

Data Source

PatentEP3783072B1Ink composition, printed product, and authenticity determination method
Publication Date: 2023.04.12 DAI NIPPON PRINTING CO LTD
  • EP3783072B1 patent drawingFigure 1~3
  • EP3783072B1 patent drawingFigure 4~5
  • EP3783072B1 patent drawingFigure 6

AI summary

An ink composition comprising one or two or more kinds of rare-earth complexes containing trivalent rare-earth ions and at least one organic ligand selected from a β-diketone ligand, a carboxylic acid ligand, a phosphine oxide ligand and a nitrogen-containing aromatic heterocyclic ligand, wherein at least one selected from the following group A and at least one selected from the following group B are contained as the trivalent rare-earth ions contained in the one or two or more kinds of rare-earth complexes: Group A: Eu3+, Sm3+, Pr3+ and Ho3+ Group B: Tb3+, Er3+, Tm3+, Dy3+, Yb3+, Nd3+, Ce3+ and Gd3+.