White ink compositions
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Solution Overview
Problem
Developing a white ink composition for textile printing that achieves good opacity and durability, particularly on dark fabrics, while overcoming the challenges of high density white metal oxide particles and ensuring jetability and washfastness.
Innovation Solution
A white ink composition comprising a liquid vehicle with water and organic co-solvent, dispersed white metal oxide particles, and polyurethane particles with polymerized sulfonated-diamines, nonionic diamines, and isocyanate-generated self-crosslinked amines, which provides improved opacity and durability through heat curing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If white metal oxide particles are used to provide opacity in white ink composition, then opacity is improved, but the high density of particles causes settling and jetability problems
Solution Approach 1:
A polyester polyol with specific molecular weight (2,000-10,000) and hydroxyl value (50-150 mg KOH/g) is used as an intermediary substance to disperse high-density white metal oxide particles (titanium dioxide, zinc oxide) in the ink vehicle. This intermediary polymer creates a stable suspension that prevents particle settling while maintaining jetability through thermal inkjet printheads.
Solution Approach 2:
The patent optimizes specific parameters including particle size distribution (D10: 50-200 nm, D50: 200-500 nm, D90: 500-1000 nm), polyester polyol molecular weight (2,000-10,000), and hydroxyl value (50-150 mg KOH/g) to achieve the balance between opacity and jetability. These parameter changes enable the ink to maintain particle suspension stability while being compatible with thermal inkjet printing systems.
2Reliability
If polymer binders are added to improve durability and opacity, then washfastness is improved, but kogation of the printhead increases
Solution Approach 1:
The patent specifies precise parameter ranges for polyester polyol (molecular weight: 2,000-10,000; hydroxyl value: 50-150 mg KOH/g) and polyurethane particles (0.1-30 wt%, with D50: 20-400 nm) to optimize the balance between washfastness and kogation. These controlled parameter changes ensure sufficient polymer content for durability while preventing excessive polymerization that would cause printhead clogging.
Solution Approach 2:
The ink composition uses a composite system combining polyester polyol with specific hydroxyl value ranges and polyurethane particles containing crosslinkable functional groups. This composite material approach provides enhanced washfastness through controlled polymerization while the specific composition ratios prevent excessive kogation by regulating the polymerization rate and final polymer structure.
3Illumination intensity
If particle size is reduced to improve dispersion and jetability, then opacity is improved, but particle density increases causing settling
Solution Approach 1:
The white metal oxide pigment is segmented into a specific particle size distribution (D10: 50-200 nm, D50: 200-500 nm, D90: 500-1000 nm) to optimize the balance between opacity and settling resistance. This segmentation creates sufficient surface area for light scattering while the polyester polyol intermediary prevents aggregation, maintaining stable suspension despite the fine particle sizes.
Solution Approach 2:
The patent creates a composite system where fine white metal oxide particles (providing opacity) are combined with polyester polyol and polyurethane particles (providing steric and electrostatic stabilization). This composite material approach allows the use of small particles for opacity while the polymer matrix prevents settling by providing repulsive forces and viscous drag.
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 composition exhibits excellent opacity and washfastness even after five washing cycles, maintaining whiteness and stability over time, with enhanced thermal inkjet printhead performance and reduced kogation.
Implementation Method 1
heat curing
Implementation Method 2
isocyanate-generated self-crosslinked amines
Implementation Method 3
white metal oxide particles dispersed in the liquid vehicle
Data Source
Figure 1~2
Figure 3
Figure 4
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.