Radiation-Curable Inkjet Ink Set Color Gamut and Adhesion

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Solution Overview

Problem

Inkjet printing for indoor applications requires a radiation-curable ink set with a wider color gamut, improved mechanical strength, enhanced adhesion to substrates, and storage stability, as well as prevention of ink bleeding from the substrate, which conventional ink sets do not adequately address.

Innovation Solution

A radiation-curable inkjet ink set comprising yellow and magenta inks with specific pigment concentrations, polymeric dispersants, and ethylenically unsaturated compounds, along with a polysiloxane-based surfactant, that cure upon exposure to actinic radiation, providing improved color gamut, mechanical strength, and substrate adhesion.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If conventional ink compositions are used for indoor printing, then basic printing function is achieved, but color gamut is insufficient and mechanical strength of cured ink is inadequate

Engineering Contradiction:
Improvemechanical strength of cured inkVSAvoidcolor gamut width
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The patent changes the chemical composition parameters of the ink by incorporating specific radiation-curable compounds (acrylates and vinyl ethers) in optimized proportions, along with photopolymerization initiators and specific pigments. This parameter optimization enables the ink to achieve both wide color gamut and high mechanical strength after UV curing, resolving the contradiction between color quality and mechanical properties

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite ink formulation combining multiple components: radiation-curable monomers (acrylates and vinyl ethers), photopolymerization initiators, pigments for color, and surfactants. This composite material approach allows simultaneous achievement of wide color gamut through pigment selection and high mechanical strength through the crosslinked polymer network formed by photopolymerization

Inventive Principle:
Principle #40Composite materials

2Strength

If conventional ink compositions are used, then printing is possible, but adhesion of cured ink to substrate is insufficient

Engineering Contradiction:
Improveadhesion of cured ink to substrateVSAvoidstorage stability
Core Design Contradiction:
StrengthVSEase of manufacture

Solution Approach 1:

The patent uses surfactants as intermediary substances that facilitate adhesion between the cured ink and substrate. The surfactants reduce surface tension and improve wetting, enabling the cured ink film to adhere strongly to various substrates. Simultaneously, the radiation-curable formulation maintains storage stability by remaining inert until UV exposure triggers polymerization

Inventive Principle:
Principle #24Intermediary (Mediator)

3Reliability

If conventional ink compositions are used for indoor printing, then basic functionality is achieved, but ink bleeding from substrate occurs

Engineering Contradiction:
Improveprevention of ink bleedingVSAvoidink composition complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent utilizes phase transition from liquid to solid through photopolymerization. The ink remains in liquid state during application and storage, then transitions to a crosslinked solid polymer network upon UV exposure. This phase transition locks the ink in place on the substrate, preventing bleeding while maintaining formulation simplicity through the use of standard radiation-curable components

Inventive Principle:
Principle #36Phase transitions

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 set achieves a wider color gamut, excellent mechanical strength, and enhanced substrate adhesion, while maintaining storage stability and preventing ink bleeding, thereby meeting the specific requirements of indoor inkjet printing.

Implementation Method 1

radiation-curable inkjet ink set comprising yellow and magenta inks with specific pigment concentrations, polymeric dispersants, and ethylenically unsaturated compounds, along with a polysiloxane-based surfactant, that cure upon exposure to actinic radiation

Methodology Applied
Scientific EffectPhotopolymerization: Photopolymerisation

Data Source

PatentUS9475950B2Radiation-curable inkjet ink set and inkjet recording method
Publication Date: 2016.10.25 FUJIFILM CORP

AI summary

To provide a radiation-curable inkjet ink set that has a sufficiently wide color gamut and is excellent in terms of mechanical strength and substrate adhesion of cured ink, and an inkjet recording method employing the ink set. A radiation-curable inkjet ink set comprises a yellow ink comprising C.I. Pigment Yellow 185 at 1.5 to 2.5 mass %, and a magenta ink comprising C.I. Pigment Red 48:4 at 1.5 to 2.5 mass %.