Radiation Curable Ink Formulation for Adhesion and Drawability

Solution Overview

Problem

Radiation curable inks with urethane (meth)acrylate oligomers exhibit high hardness, leading to insufficient adhesion and drawability issues, causing floating or cracking during post-processing operations like cutting or punching, due to their high hardness and low adhesion with recording media.

Innovation Solution

Incorporating specific compounds represented by Formulas (I), (II), and (III), including vinyl ether group-containing (meth)acrylic acid esters, glycol-based di(meth)acrylates, and monofunctional urethane bond-containing (meth)acrylates, which enhance flexibility, adhesion, and curing properties, while adjusting the content of these compounds within specific ranges to optimize viscosity and performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If urethane (meth)acrylate oligomer with two or more (meth)acrylic functional groups is used, then the coating film has high hardness, but the adhesion with recording medium becomes insufficient and drawability is poor

Engineering Contradiction:

ImprovehardnessVSAvoidadhesion

Core Design Contradiction:

StrengthVSReliability

Solution Approach 1:

The patent changes the functional group count parameter from 2 or more (in prior art) to exactly 1 (monofunctional), which fundamentally alters the crosslinking density and network structure of the cured coating film, reducing hardness while improving adhesion and drawability

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite ink formulation combining monofunctional urethane (meth)acrylate (Formula III) with other (meth)acrylate compounds having different functional groups, achieving a balanced coating film with optimized hardness, adhesion, and drawability through synergistic interaction of components

Inventive Principle:

Principle #40Composite materials

2Strength

If urethane (meth)acrylate oligomer with two or more (meth)acrylic functional groups is used, then the coating film has high hardness, but floating or cracking occurs during post-processing operations

Engineering Contradiction:

ImprovehardnessVSAvoidfloating and cracking

Core Design Contradiction:

StrengthVSObject-generated harmful factors

Solution Approach 1:

The patent changes the functional group count parameter from 2 or more (in prior art) to exactly 1 (monofunctional), which fundamentally alters the crosslinking density and network structure of the cured coating film, reducing hardness while improving adhesion and drawability

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent preemptively addresses potential floating and cracking issues by selecting monofunctional urethane (meth)acrylate with specific molecular structure characteristics that inherently provide better flexibility and adhesion, preventing these defects before they occur during post-processing

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

3Use of energy by moving object

If multifunctional (meth)acrylate compounds are used to improve curing reactivity, then the coating film has high hardness, but the viscosity and flexibility become insufficient

Engineering Contradiction:

Improvecuring reactivityVSAvoidflexibility

Core Design Contradiction:

Use of energy by moving objectVSStrength

Solution Approach 1:

The patent changes the functional group count parameter from 2 or more (in prior art) to exactly 1 (monofunctional), which fundamentally alters the crosslinking density and network structure of the cured coating film, reducing hardness while improving adhesion and drawability

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 proposed solution results in radiation curable inks with improved adhesion, drawability, and scratch resistance, preventing floating and cracking during post-processing, and maintaining excellent curing properties and discharge stability.

Implementation Method 1

radiation curable ink, which cures by irradiation with radiation

Methodology Applied

Scientific EffectPhotopolymerization: Photopolymerisation

Data Source

PatentUS11066563B2Radiation curable ink

Publication Date: 2021.07.20 SEIKO EPSON CORP

AI summary

A radiation curable ink comprises a compound represented by the following Formula (I):a compound represented by the following Formula (II):and a compound represented by the following Formula (III):