White ink compositions
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Solution Overview
Problem
Existing white ink compositions for textile printing face challenges in achieving good opacity on dark fabrics and maintaining durability during wash cycles, due to the high density of white metal oxide particles and the need for a suitable combination of polymer binders and pigments that ensure jetability and washfastness.
Innovation Solution
A white ink composition is developed, comprising a liquid vehicle with water and organic co-solvent, dispersed white metal oxide particles, and polyurethane particles with a polyurethane polymer containing polymerized sulfonated-diamines, nonionic diamines, and isocyanate-generated self-crosslinked amines. This composition is designed to provide improved opacity and durability on dark fabrics by optimizing the combination of white metal oxide particles and polyurethane particles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If white metal oxide particles are used to provide opacity on dark fabrics, then opacity is improved, but particle packing leads to reduced opacity and poor jetability
Solution Approach 1:
A dispersant is introduced as an intermediary substance between the white metal oxide particles and the liquid vehicle. The dispersant adsorbs onto the particle surfaces, providing steric or electrostatic repulsion that prevents particle aggregation and packing. This allows the high-density opaque particles to remain uniformly dispersed in the ink composition, maintaining both opacity and jetability through the printhead
Solution Approach 2:
The patent modifies the physical parameters of the ink composition by controlling particle size distribution, concentration, and surface properties of the metal oxide particles. By optimizing these parameters and adjusting the liquid vehicle composition (viscosity, surface tension), the ink achieves sufficient flowability for jetability while maintaining particle dispersion for opacity
2Reliability
If polymer binders are added to maintain durability during wash cycles, then washfastness is improved, but the combination of binder and pigment becomes difficult to optimize for both jetability and durability
Solution Approach 1:
The patent employs a composite formulation combining white metal oxide particles (for opacity) with polymer binders (for durability). The composite achieves synergistic effects where the dispersant ensures uniform distribution of both components, the binder provides washfastness by binding particles to fabric, and the overall formulation maintains jetability through proper viscosity and surface tension control
Solution Approach 2:
The patent optimizes multiple formulation parameters simultaneously: polymer binder molecular weight and concentration, metal oxide particle size and surface treatment, dispersant type and amount, and liquid vehicle composition. By systematically adjusting these parameters, the formulation achieves the difficult balance of washfastness, jetability, and opacity
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 white ink composition achieves excellent opacity on dark fabrics and maintains acceptable opacity after five wash cycles, demonstrating improved washfastness and stability over time. Additionally, the polyurethane particles exhibit good thermal inkjet printhead performance, including high drop weight and velocity, and acceptable Turn On Energy (TOE) curve values.
Implementation Method 1
The polyurethane particles include a polyurethane polymer with polymerized sulfonated-diamines, polymerized nonionic diamines, and isocyanate-generated self-crosslinked amines
Data Source
AI summary
The present disclosure includes a white ink composition including a liquid vehicle with water and organic co-solvent, from 0.5 wt % to 15 wt % white metal oxide particles dispersed in the liquid vehicle, and from 0.1 wt % to 30 wt % of polyurethane particles dispersed in the liquid vehicle. The polyurethane particles include a polyurethane polymer with polymerized sulfonated-diamines, polymerized nonionic diamines, and isocyanate-generated self-crosslinked amines.