Radiation-Curing Ink Composition Adhesion Viscosity Trade-off

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Solution Overview

Problem

Current ink jet recording methods face challenges in achieving high adhesion, abrasion resistance, and storage stability while maintaining low viscosity, particularly when used on resin-based recording media, which are essential for applications like labels.

Innovation Solution

The development of a radiation-curing ink jet ink composition that includes specific ratios of urethane (meth)acrylate, (meth)acrylate with an aromatic ring, and alicyclic groups, along with a monofunctional monomer containing a heterocyclic nitrogen atom, and an acylphosphine oxide polymerization initiator, which enhances adhesion, abrasion resistance, and storage stability while keeping viscosity low.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If the content of monomer including urethane linkage is increased to enhance adhesion and abrasion resistance, then the chemical composition needs to be improved to maintain storage stability and low viscosity

Engineering Contradiction:
Improveadhesion and abrasion resistanceVSAvoidstorage stability
Core Design Contradiction:
StrengthVSStability of the object's composition

Solution Approach 1:

The patent applies parameter changes by precisely controlling the urethane linkage content within 2.8-4.7 mmol/g range and setting specific proportions of photopolymerizing monomers (5-30 mass%) and non-photopolymerizing monomers (70-45 mass%). This optimized composition ratio maintains storage stability while achieving sufficient adhesion and abrasion resistance on resin recording media.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent uses composite materials by combining multiple types of monomers including photopolymerizing monomers with urethane linkages, photopolymerizing monomers without urethane linkages, and non-photopolymerizing monomers. This composite approach balances adhesion enhancement with storage stability and viscosity control.

Inventive Principle:
Principle #40Composite materials

2Strength

If the content of monomer including urethane linkage is increased to enhance adhesion and abrasion resistance, then the viscosity control becomes more difficult

Engineering Contradiction:
Improveadhesion and abrasion resistanceVSAvoidviscosity control
Core Design Contradiction:
StrengthVSEase of operation

Solution Approach 1:

The patent controls viscosity by adjusting the overall monomer content and selecting monomers with appropriate molecular weights and structures. The balanced composition of photopolymerizing and non-photopolymerizing monomers ensures the ink maintains suitable viscosity for jet recording while providing sufficient adhesion and abrasion resistance.

Inventive Principle:
Principle #35Parameter changes

3Stability of the object's composition

If the chemical composition is improved to maintain storage stability, then the adhesion and abrasion resistance may be compromised

Engineering Contradiction:
Improvestorage stabilityVSAvoidadhesion and abrasion resistance
Core Design Contradiction:
Stability of the object's compositionVSStrength

Solution Approach 1:

The patent employs composite materials by formulating a mixture of photopolymerizing monomers containing urethane linkages (for adhesion), photopolymerizing monomers without urethane linkages (for stability), and non-photopolymerizing monomers (for viscosity control). This composite formulation achieves simultaneous optimization of storage stability and adhesion/abrasion resistance.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent applies local quality by assigning different functional roles to different monomer components: photopolymerizing monomers with urethane linkages provide adhesion to the resin substrate, while photopolymerizing monomers without urethane linkages and non-photopolymerizing monomers contribute to storage stability and viscosity control, respectively.

Inventive Principle:
Principle #3Local quality

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 achieves excellent adhesion, abrasion resistance, storage stability, and low viscosity, enabling high-quality image formation on resin-based media with improved flexibility and stretchability, suitable for applications requiring high bendability and durability.

Implementation Method 1

a photocuring ink jet printing ink composition that includes at least a photopolymerizing compound and a photopolymerization initiator

Methodology Applied
Scientific EffectPhotopolymerization: Photopolymerisation

Data Source

PatentUS11680177B2Ink composition
Publication Date: 2023.06.20 SEIKO EPSON CORP

AI summary

A radiation-curing ink jet ink composition includes a urethane (meth)acrylate including one (meth)acryloyl group, the amount of the urethane (meth)acrylate being 5.0% by mass or more and 30.0% by mass or less of the total amount of the ink composition, and a (meth)acrylate including an aromatic ring and one (meth)acryloyl group, the amount of the (meth)acrylate being 4.0% by mass or more and 50.0% by mass or less of the total amount of the ink composition.