UV-curable inkjet inks

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Solution Overview

Problem

Cationic UV-curable ink formulations for digital inkjet printing on textiles suffer from brittleness, insufficient elongation properties, poor flexibility, and stiffness, which affect the hand feel and mechanical properties of the printed images.

Innovation Solution

A process involving the application of an alkaline softener onto freshly printed and UV-irradiated cationic UV-curable ink on substrates within a specific time interval, allowing for continued polymerization without impairing the curing process, thereby enhancing the hand feel and mechanical properties of the printed images.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If cationic UV-curable ink formulations are used for digital inkjet printing on textiles, then high degrees of curing and durability are achieved, but brittleness and stiffness increase, reducing flexibility and hand feel

Engineering Contradiction:
Improvecuring degree and durabilityVSAvoidflexibility and elongation
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The patent applies parameter changes by modifying the chemical composition parameters of the ink formulation. Specifically, it uses a cationic UV-curable system with epoxide monomers and oligomers combined with specific photoinitiators that enable high curing degrees while maintaining flexibility. The formulation parameters (monomer/oligomer ratios, photoinitiator types and concentrations) are optimized to achieve both durability and flexibility, resolving the contradiction between complete curing and material brittleness.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If cationic UV-curable ink is printed and immediately cured, then high curing degree is achieved, but the printed image becomes brittle and loses flexibility

Engineering Contradiction:
Improvecuring degreeVSAvoidhand feel and flexibility
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The patent applies preliminary action by incorporating flexibility-enhancing components (such as specific epoxide monomers with appropriate molecular weights and flexible oligomers) into the ink formulation before printing. This preliminary incorporation ensures that the flexible structure is built into the polymer network during curing, rather than attempting to add flexibility after the brittle cured film has formed. The photoinitiator system is also pre-selected to enable controlled curing that maintains chain flexibility.

Inventive Principle:
Principle #10Preliminary action

3Reliability

If UV radiation is applied to cure the ink, then durability and curing completeness improve, but the material becomes more rigid and less flexible

Engineering Contradiction:
ImprovedurabilityVSAvoidflexibility
Core Design Contradiction:
ReliabilityVSShape

Solution Approach 1:

The patent applies composite materials by combining multiple components with complementary properties: epoxide monomers (for crosslinking and durability), flexible oligomers (for chain mobility and flexibility), and photoinitiators (for UV curing). This composite formulation creates a polymer network that simultaneously achieves high curing completeness, durability, and flexibility. The synergistic interaction between these components resolves the contradiction between rigidity from complete curing and flexibility from incomplete curing.

Inventive Principle:
Principle #40Composite materials

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 significantly improves the mechanical properties and hand feel of printed images by reducing brittleness and enhancing flexibility, while maintaining high degrees of curing and durability.

Implementation Method 1

exposing the surface to UV radiation (irradiating the image with UV light) to thereby initiating curing of the ink constituting the image

Methodology Applied
Scientific EffectPhotopolymerisation: Photopolymerisation

Data Source

PatentUS20250065663A1UV-curable inkjet inks
Publication Date: 2025.02.27 KORNIT DIGITAL LTD

AI summary

A process for digital printing on fabrics using cationic UV-curable ink compositions having acceptable wash-fastness and acceptable hand-feel.