Aqueous Cationic Polyurethane Dispersion Ink Feathering
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Solution Overview
Problem
Existing aqueous cationic polyurethane dispersions face challenges such as poor water resistance, color retention, and image quality issues in digital printing due to ink spreading and feathering, which are not adequately addressed by current technologies that often require harmful solvents and result in low molecular weight polymers with low solids content.
Innovation Solution
Development of an aqueous cationic polyurethane dispersion with tethered tertiary amino groups, either laterally or terminally attached, which are optionally neutralized or quaternized, to enhance interaction with water and improve dispersability, resulting in high-molecular-weight polymers with high solids content and low viscosity, suitable for digital printing applications.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional aqueous cationic polyurethane dispersions are used, then digital printing applications can be performed, but water resistance is poor and blotching occurs
Solution Approach 1:
The patent modifies the molecular weight parameter (increasing to 10,000-1,000,000 g/mol) and solids content parameter (increasing to 20-80% wt) of the polyurethane dispersion, which changes the physical properties to improve water resistance and prevent blotching while maintaining digital printing functionality
Solution Approach 2:
The patent creates a composite aqueous dispersion system combining polyurethane polymers with specific molecular weight ranges and solids content, forming a composite material that provides both water resistance and print quality without requiring harmful solvents
2Productivity
If ink is applied onto the media, then digital printing can be performed, but ink spreads and feathers causing fuzzy appearance
Solution Approach 1:
The patent adjusts the solids content parameter to 20-80% wt and molecular weight to 10,000-1,000,000 g/mol, which controls ink absorption characteristics to prevent spreading and feathering while maintaining productive digital printing operation
Solution Approach 2:
The patent creates local quality differences in the media surface through the polyurethane dispersion application, providing controlled ink absorption zones that maintain sharp image edges while allowing ink uptake in intended areas
3Reliability
If existing technologies are used to improve water resistance, then some performance enhancement is achieved, but harmful solvents are required
Solution Approach 1:
The patent converts the previously harmful effect of low solids content and solvent reliance into a benefit by formulating high solids content (20-80% wt) aqueous dispersions that eliminate harmful solvents while enhancing water resistance through optimized polymer concentration and molecular weight
Solution Approach 2:
The patent fundamentally changes the composition parameters by increasing solids content to 20-80% wt and molecular weight to 10,000-1,000,000 g/mol, transforming the system from solvent-dependent to water-based high-solids formulation that achieves water resistance without harmful solvents
4Ease of operation
If low molecular weight polyurethanes are used, then dispersability is achieved, but solids content is low
Solution Approach 1:
The patent simultaneously optimizes molecular weight (10,000-1,000,000 g/mol) and solids content (20-80% wt) parameters, achieving a balance where high molecular weight provides structural integrity for high solids content while maintaining adequate dispersability through controlled polymer architecture
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 solution provides superior water resistance, reduced wicking, undistorted colors, and fast drying rates, with enhanced affinity to anionic substrates and compatibility with cationic substances, improving overall digital printing performance.
Implementation Method 1
tertiary amino groups, e.g., tethered tertiary amine groups (amine groups in the side chain) or terminal tertiary amino groups with multiple tertiary amino groups per terminus
Implementation Method 2
aqueous cationic polyurethane dispersions wherein the dispersability and performance of the polyurethanes are enhanced by tertiary amino groups
Data Source
AI summary
An aqueous cationic polyurethane dispersion for waterborne digital print and other applications comprising an aqueous dispersion of polyurethane having properly positioned tertiary amino groups, e.g., tethered tertiary amino group separated from backbone by at least two intervening atoms or terminal tertiary amino groups with multiple tertiary amino groups per terminus, where said amino groups are optionally partially quaternized and/or neutralized.