Hexaboride Particle Dispersion for Offset Printing

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Solution Overview

Problem

Existing near infrared absorbing materials for offset printing, such as phthalocyanine compounds and tin-doped indium oxide, face issues with temperature sensitivity, visibility contrast, and compatibility with offset printing equipment, leading to reduced durability and reading accuracy, as well as the risk of particle attachment to non-image areas and rubber blanket dissolution.

Innovation Solution

A near infrared absorbing fine particle dispersion liquid is developed using hexaboride fine particles dispersed in a petroleum-based solvent with a dispersant, maintaining low viscosity and particle size, allowing for clear contrast and reliable offset printing without dissolving rubber blankets.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If phthalocyanine compound is used as infrared absorbing material, then infrared absorption property is achieved, but durability is inferior due to temperature and ultraviolet ray influence

Engineering Contradiction:
ImprovedurabilityVSAvoidtemperature and ultraviolet ray influence
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent changes the material parameter from organic phthalocyanine compound to inorganic hexaboride fine particles (XB6, where X is La, Ce, Pr, Nd, Gd, Tb, Dy, Ho, Y, Sm, Eu, Er, Tm, Yb, Lu, Sr, or Ca). This parameter change transforms the material's resistance properties, making it insensitive to temperature and ultraviolet rays while maintaining infrared absorption functionality.

Inventive Principle:
Principle #35Parameter changes

2Measurement precision

If tin-doped indium oxide is used as infrared absorbing material, then infrared absorption is achieved, but visible light contrast is insufficient and reading accuracy deteriorates

Engineering Contradiction:
Improvereading accuracyVSAvoidvisible light contrast
Core Design Contradiction:
Measurement precisionVSIllumination intensity

Solution Approach 1:

The patent changes the material composition from tin-doped indium oxide to hexaboride fine particles with specific atomic ratios (X:B = 1:6). This parameter change optimizes the optical properties, creating sufficient contrast in the visible light region while maintaining infrared absorption, thereby improving reading accuracy.

Inventive Principle:
Principle #35Parameter changes

3Illumination intensity

If near infrared absorbing fine particles are dispersed in alcohol such as ethanol, then high visible light transmittance is achieved, but particles attach to non-image part of plate due to high polarity

Engineering Contradiction:
Improvevisible light transmittanceVSAvoidparticle attachment to non-image part
Core Design Contradiction:
Illumination intensityVSObject-generated harmful factors

Solution Approach 1:

The patent changes the solvent parameter from polar alcohol (ethanol) to non-polar petroleum-based solvent. This parameter change alters the interaction between solvent and plate surface, preventing particle attachment to non-image areas while maintaining the high visible light transmittance property of the hexaboride particles.

Inventive Principle:
Principle #35Parameter changes

4Illumination intensity

If near infrared absorbing fine particles are dispersed in organic solvent such as toluene, then high visible light transmittance is achieved, but rubber blanket dissolution occurs

Engineering Contradiction:
Improvevisible light transmittanceVSAvoidrubber blanket dissolution
Core Design Contradiction:
Illumination intensityVSObject-generated harmful factors

Solution Approach 1:

The patent changes the solvent parameter from aromatic organic solvent (toluene) to aliphatic petroleum-based solvent. This parameter change reduces the solvent's affinity for rubber materials, eliminating the dissolution problem while preserving the optical properties needed for visible light transmittance.

Inventive Principle:
Principle #35Parameter changes

5Reliability

If petroleum-based solvent is used as dispersant, then rubber blanket dissolution is prevented, but particle dispersion force is insufficient and viscosity increases

Engineering Contradiction:
Improvecompatibility with offset printingVSAvoidparticle dispersion force
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The patent introduces a dispersant as an intermediary substance between the petroleum-based solvent and hexaboride fine particles. This dispersant mediates the interaction, providing sufficient particle dispersion force while maintaining the compatibility of the petroleum-based solvent with offset printing equipment and rubber blankets.

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 solution enables high-quality offset printing with enhanced durability, clear contrast, and improved reading accuracy, while preventing particle attachment to non-image areas and ensuring compatibility with offset printing equipment, thus providing an effective anti-counterfeit solution.

Implementation Method 1

The absorption mechanism of the near-infrared absorbing fine particles is believed to be due to localized surface plasmon resonance

Methodology Applied
Scientific EffectLocalized surface plasmon resonance: Absorption (EM radiation)

Implementation Method 2

a dispersant soluble in the solvent and having a fatty acid in its structure

Methodology Applied
Scientific EffectWetting: Wetting

Data Source

PatentEP3252114B1Near-infrared ray absorbing microparticle dispersion solution, production method thereof, counterfeit-preventing ink composition using said near-infrared ray absorbing microparticle dispersion solution, and Anti-counterfeit printed matter using said near-infrared ray absorbing microparticles
Publication Date: 2022.10.26 SUMITOMO METAL MINING CO LTD
  • EP3252114B1 patent drawingFigure 1~2
  • EP3252114B1 patent drawingFigure 3~4
  • EP3252114B1 patent drawing

AI summary

Provided are a near infrared absorbing fine particle dispersion liquid having an absorption ability in a near infrared region, a clear contrast, and applicable to offset printing, and a method for producing the same, an anti-counterfeit ink composition using the near infrared absorbing fine particle dispersion liquid and an anti-counterfeit printed matter using near infrared absorbing fine particles. Also provided are a near infrared absorbing fine particle dispersion liquid containing a solvent of one or more kinds selected from petroleum-based solvents; near infrared absorbing fine particles in an amount of 2 mass% or more and 25 mass% or less, selected from one or more kinds of hexaboride fine particles expressed by a general formula XBa, and a dispersant soluble in the solvent and having a fatty acid in its structure, and an anti-counterfeit ink composition containing the near infrared absorbing fine particle dispersion liquid. Also provided is an anti-counterfeit printed matter excellent in anti-counterfeit effect due to the printed matter containing the near infrared absorbing fine particles.