Radiation-Curable Ink Jet Composition for Flexible Packaging

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Solution Overview

Problem

Ink jet processes for flexible packaging applications face challenges with color strength when using thin ink coatings, particularly with magenta inks containing C.I. Pigment Red 122 and C.I. Pigment Red 48:4, as they result in insufficient color strength and inefficiencies during the rolling process due to added ink thickness.

Innovation Solution

A radiation-curable ink jet composition is developed, containing C.I. Pigment Red 57:1 as the primary colorant, along with specific polymerizable compounds and photopolymerization initiators, which is ejected and cured to form a thin, high-color-strength coating with a maximum thickness of 5 μm or less, ensuring efficient rolling and improved color reproduction.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If a thin ink coating is used for flexible packaging, then the rolling efficiency is improved, but the color strength becomes insufficient

Engineering Contradiction:
Improverolling efficiencyVSAvoidcolor strength
Core Design Contradiction:
ProductivityVSStrength

Solution Approach 1:

The patent changes the chemical composition parameters of the ink jet composition by incorporating specific polymerizable compounds and photopolymerization initiators, enabling the ink to cure into a thin yet strong coating that maintains both thinness and color strength through controlled polymerization rather than relying on coating thickness alone

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite ink jet composition combining pigment particles with polymerizable compounds and photopolymerization initiators, forming a multi-component system where the cured coating achieves enhanced mechanical properties and color strength through the synergistic interaction of these materials

Inventive Principle:
Principle #40Composite materials

2Strength

If a thick ink coating is used to improve color strength, then the color strength is sufficient, but the rolling process becomes inefficient due to extra thickness

Engineering Contradiction:
Improvecolor strengthVSAvoidrolling efficiency
Core Design Contradiction:
StrengthVSProductivity

Solution Approach 1:

The patent modifies the physical and chemical parameters of the ink coating through photopolymerization, transforming the liquid ink into a cured coating with controlled thickness and enhanced properties, allowing thin coatings to achieve the color strength previously requiring thick coatings

Inventive Principle:
Principle #35Parameter changes

3Productivity

If conventional magenta inks are used with thin coatings, then the coating thickness is reduced for better rolling, but the color strength becomes unacceptable

Engineering Contradiction:
Improverolling efficiencyVSAvoidcolor strength
Core Design Contradiction:
ProductivityVSStrength

Solution Approach 1:

The patent changes the chemical composition by incorporating specific polymerizable compounds and photopolymerization initiators, enabling the ink to cure into a thin yet strong coating that maintains both thinness and color strength through controlled polymerization rather than relying on coating thickness alone

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent employs a disposable ink jet composition that is applied and then cured, eliminating the need for thick coatings and allowing for thin, efficient rollable packaging while maintaining adequate color strength through the specialized composition

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

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 achieves improved color strength and ease of rolling for flexible packaging applications by maintaining a thin cured coating, enhancing handling and color reproduction while preventing medium thickening during the rolling process.

Implementation Method 1

a curing step, in which the ejected ink jet composition is irradiated with radiation to give a cured coating of the ink jet composition

Methodology Applied
Scientific EffectPhotopolymerization: Photopolymerisation

Data Source

PatentUS11787961B2Ink jet process and recording
Publication Date: 2023.10.17 SEIKO EPSON CORP

AI summary

An ink jet process includes an ejection step, in which a radiation-curable ink jet composition is ejected from an ink jet head to a recording medium, and a curing step, in which the ejected ink jet composition is irradiated with radiation to give a cured coating of the ink jet composition. The ink jet composition contains at least one polymerizable compound, at least one photopolymerization initiator, and C.I. Pigment Red 57:1. The C.I. Pigment Red 57:1 constitutes 4.0% by mass or more of the total amount of the ink jet composition, and the cured coating has a maximum thickness of 5 μm or less.