LED-Curable Inkjet Ink Composition for Low-Migration Film Adhesion

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Existing inkjet ink compositions for food packaging fail to provide sufficient adhesion to resin films and LED curability while preventing migration of unreacted monomers and photopolymerization initiators, and adjusting viscosity for inkjet discharge is difficult.

Innovation Solution

An active energy ray-curable inkjet ink composition comprising specific components: hydroxy group-containing monofunctional (meth)acrylates, polyfunctional monomers with ether bonds, amine-modified oligomers, and photopolymerization initiators, with controlled proportions to ensure adhesion, curability, and anti-migration properties.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If polymeric initiators and certain monomers are used to reduce migration, then migration resistance is improved, but viscosity adjustment to a range permitting discharge from inkjet heads becomes difficult

Engineering Contradiction:
Improvemigration resistanceVSAvoidviscosity adjustment
Core Design Contradiction:
Object-affected harmful factorsVSEase of manufacture

Solution Approach 1:

The patent changes the chemical structure parameters of the monomer components by introducing specific functional groups (ether bonds, hydroxyl groups, carboxyl groups) to achieve the desired balance between migration resistance and viscosity characteristics. This allows the composition to discharge from inkjet heads while maintaining anti-migration properties.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite ink composition by combining multiple carefully selected components: specific monomers with ether bonds, monomers with hydroxyl or carboxyl groups, polymers with carboxyl groups, and photopolymerization initiators. This composite approach allows each component to contribute specific properties that collectively resolve the viscosity-migration resistance contradiction.

Inventive Principle:
Principle #40Composite materials

2Ease of operation

If conventional ink compositions are used on food packaging materials, then printing functionality is achieved, but migration into food may occur

Engineering Contradiction:
Improveprinting functionalityVSAvoidmigration into food
Core Design Contradiction:
Ease of operationVSObject-affected harmful factors

Solution Approach 1:

The patent employs monomers and oligomers with specific functional groups that are designed to fully polymerize and become part of the crosslinked network, leaving no migratable low-molecular-weight components. The use of polymeric initiators and carefully selected monomers ensures complete reaction and minimal residual components that could migrate into food.

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

Solution Approach 2:

The patent uses specific polymer components with carboxyl groups and monomers with hydroxyl or carboxyl groups as intermediaries that enhance adhesion to food packaging substrates while forming a barrier layer that prevents migration into food. These intermediary components create strong bonding to the substrate and form a protective barrier.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Object-affected harmful factors

If materials with high molecular weight are used to prevent migration, then migration resistance is improved, but adhesion to resin films deteriorates

Engineering Contradiction:
Improvemigration resistanceVSAvoidadhesion to resin films
Core Design Contradiction:
Object-affected harmful factorsVSStrength

Solution Approach 1:

The patent applies local quality by having different components perform different functions: monomers with ether bonds provide migration resistance through their molecular structure, while monomers with hydroxyl or carboxyl groups and polymers with carboxyl groups provide adhesion to resin films through their polar functional groups. Each component is optimized for its specific local function within the overall composition.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent creates a composite system where high molecular weight polymeric initiators provide migration resistance while low molecular weight monomers with specific functional groups (hydroxyl, carboxyl) provide adhesion to resin films. The synergistic combination allows both high migration resistance and good adhesion to be achieved simultaneously.

Inventive Principle:
Principle #40Composite materials

4Ease of operation

If ink composition is printed in heated state to improve discharge, then viscosity is reduced for better flow, but migration may increase

Engineering Contradiction:
Improvedischarge performanceVSAvoidmigration in printed areas
Core Design Contradiction:
Ease of operationVSObject-affected harmful factors

Solution Approach 1:

The patent employs preliminary action by pre-designing the ink composition with components that have inherent thermal stability and low migration tendency. The specific selection of monomers with ether bonds and polymeric initiators ensures that even when heated during printing, the components remain stable and do not migrate, allowing heated state printing without increasing migration risk.

Inventive Principle:
Principle #10Preliminary action

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 composition achieves excellent adhesion to resin films, LED curability, and prevents migration of components, suitable for food packaging applications with adjustable viscosity and good bonding to various base materials.

Implementation Method 1

active energy ray-curable inkjet ink composition... polymerizable compounds... photopolymerization initiator... irradiating light onto the coating film

Methodology Applied
Scientific EffectPhotopolymerization: Photopolymerisation

Data Source

PatentEP4364950B1Actinic ray-curable inkjet ink composition
Publication Date: 2026.04.22 SAKATA INX

AI summary

While inkjet ink compositions designed to reduce migration are known, an object of the present invention is to provide an inkjet ink composition that provides, in addition to the above, sufficient adhesion to resin films as well as excellent LED curability, while allowing for printing on films used for food packaging that are subject to more stringent property requirements. As a solution, an active energy ray-curable inkjet ink composition satisfying all of the requirements of (A) to (E) below is provided. (A) it contains hydroxy group-containing monofunctional (meth)acrylates by 20.0 to 60.0% by mass in the total amount of all polymerizable components. (B) it contains polyfunctional monomers having ether bonds. (C) it contains amine-modified oligomers by 10.0 to 50.0% by mass in the total amount of all polymerizable components. (D) it contains ethyl phenyl(2,4,6-trimethylbenzoyl)phosphinate as a polymerization initiator. (E) it contains polymeric sensitizers.