Photocurable Ink Composition for High Gloss Cured Films

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Solution Overview

Problem

Existing photocurable ink compositions with amine compounds struggle to achieve high glossiness in the cured film.

Innovation Solution

A photocurable ink composition containing an amine A with a number-average molecular weight of less than 1,000 and an amine B with a molecular weight of 1,000 or more, along with a monofunctional or bifunctional radical-polymerizable monomer, to form a cured film with high glossiness.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a photocurable ink composition containing amine compounds is used, then curability and film formation are achieved, but glossiness of the cured film is insufficient

Engineering Contradiction:

ImprovecurabilityVSAvoidglossiness

Core Design Contradiction:

ReliabilityVSShape

Solution Approach 1:

The invention changes the molecular weight parameter of the amine compound to resolve the contradiction. By using an amine compound with a number-average molecular weight of 100 or more and less than 1,000 (specific range), the composition achieves both reliable curability and high glossiness. This parameter optimization allows the amine to effectively suppress oxygen inhibition while maintaining film surface quality for high glossiness.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The invention uses a composite approach by combining the specific amine compound (with controlled molecular weight) with radical-polymerizable monomers and oligomers. This composite material system works synergistically: the amine suppresses oxygen inhibition to ensure curability, while the controlled molecular weight prevents surface defects, achieving both curability and high glossiness simultaneously.

Inventive Principle:

Principle #40Composite materials

2Ease of operation

If oxygen is present during polymerization, then the ink composition can be applied and cured, but radical polymerization is inhibited leading to poor curability consistency across film thickness

Engineering Contradiction:

ImproveapplicabilityVSAvoidcurability consistency

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

The invention converts the harmful effect of oxygen (which inhibits radical polymerization) into a beneficial outcome. By incorporating a specific amine compound with controlled molecular weight, the composition suppresses oxygen inhibition, allowing the ink to be applied and cured reliably with consistent curability across the film thickness, thus transforming oxygen from a harmful factor to a manageable condition.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

3Stability of the object's composition

If high molecular weight amine compounds are used, then storage stability may improve, but glossiness and surface quality of the cured film deteriorate

Engineering Contradiction:

Improvestorage stabilityVSAvoidsurface quality

Core Design Contradiction:

Stability of the object's compositionVSShape

Solution Approach 1:

The invention optimizes the molecular weight parameter of the amine compound to a specific range (number-average molecular weight of 100 or more and less than 1,000). This parameter control ensures that the amine is small enough to migrate to the surface and suppress oxygen inhibition effectively, resulting in high glossiness and surface quality, while still providing adequate storage stability.

Inventive Principle:

Principle #35Parameter changes

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 suppresses radical polymerization inhibition due to oxygen, ensuring consistent curability across the film thickness direction and resulting in a cured film with improved glossiness, blocking resistance, scratch resistance, and adhesiveness.

Implementation Method 1

a photocurable ink composition containing an amine A with a number-average molecular weight of less than 1,000 and an amine B with a molecular weight of 1,000 or more, along with a monofunctional or bifunctional radical-polymerizable monomer

Methodology Applied

Scientific EffectRadical polymerization: Photopolymerisation

Implementation Method 2

Methodology Applied

Scientific EffectPhotocuring: Photopolymerisation

Data Source

PatentEP3778792B1Photocurable ink composition and image forming method

Publication Date: 2025.01.22 FUJIFILM CORP

AI summary

Provided are a method for forming an image, and a photocurable ink composition including an amine A which is an amine compound having an α-hydrogen atom and a number-average molecular weight of less than 1,000, an amine B which is an amine compound having an α-hydrogen atom and a number-average molecular weight of 1,000 or more, and at least one of a monofunctional radical-polymerizable monomer or a bifunctional radical-polymerizable monomer, in which a total content of the monofunctional radical-polymerizable monomer and the bifunctional radical-polymerizable monomer is 50% by mass or more based on a total amount of the photocurable ink composition.