Aqueous Radiation Curable Ink Composition for Nozzle Reliability
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Solution Overview
Problem
Current inkjet ink technologies face challenges such as environmental risks from solvent evaporation, high costs of 100% solid UV curable inks, brittleness due to high cross-linking, and inadvertent curing in print-heads, which affect print quality and reliability.
Innovation Solution
An aqueous radiation curable ink composition using anionic acrylated polyurethane and non-volatile cations, which is redispersible in water before curing and water-resistant after exposure to actinic radiation or electron beam, decoupling the hardening process from printing and maintaining nozzle reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If 100% solid UV curable inks are used, then curing is ensured on substrate while preventing ink curing in print-head, but the material cost increases significantly
Solution Approach 1:
The invention changes the chemical parameters of the ink formulation by using water-based polyurethane dispersions with specific functional groups instead of traditional 100% solid UV inks, achieving cost reduction while maintaining curing performance through parameter optimization
Solution Approach 2:
The invention replaces expensive radiation-curable materials with cheaper water-based alternatives that achieve the same functional outcome, using inexpensive polyurethane dispersions and simple photoinitiators to reduce material costs while maintaining reliability
2Productivity
If high levels of monomers and photoinitiators are used to enable low viscosity and fast curing, then printing performance is improved, but health and safety risks increase due to migration to surrounding environment
Solution Approach 1:
The invention changes the concentration parameters by using low levels of photoinitiators (0.1-5% wt) and specific monomer types, achieving fast curing through optimized formulation rather than high concentrations, thereby reducing health and safety risks while maintaining productivity
Solution Approach 2:
The invention uses composite formulations combining water-based polyurethane dispersions with specific photoinitiators and monomers, creating a synergistic system that achieves fast curing at low concentrations, reducing harmful migration while maintaining printing speed
3Quantity of substance
If thermal curing mechanism is used for water based latex inks, then low viscosity is achieved, but inadvertent curing occurs in print-head nozzles leading to blocked or misdirected nozzles
Solution Approach 1:
The invention replaces the thermal curing mechanism with a radiation-based curing mechanism (UV or electron beam), eliminating the need for heat that causes inadvertent curing in nozzles, while maintaining low viscosity through water-based formulation
Solution Approach 2:
The invention extracts the thermal curing step from the process, using radiation curing instead, thereby removing the harmful thermal effect that causes nozzle blocking while preserving the low viscosity characteristic
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 mechanical and solvent resistance while maintaining flexibility, preventing nozzle blockage and ensuring reliable print-head performance, with improved environmental and health safety profiles.
Implementation Method 1
The ink composition is water-resistant after curing by electron beam or actinic radiation
Data Source
AI summary
The present invention relates to an aqueous radiation curable ink composition. The ink composition comprises: (a) an aqueous dispersion comprising anionic acrylated polyurethane and non-volatile cations; (b) at least one non-ionic or anionic surfactant; (c) at least one humectant selected from the group consisting of: polyol, polyether, polyether alcohol, polyether polyols, urea, and amide; and (d) water. The ink composition does not contain a water-soluble or water-miscible (meth)acrylate monomer. The ink composition is redispersible in water after drying and before curing, and the ink composition is water-resistant after curing by electron beam or actinic radiation.