Low Density TiO2 Pigments for Inkjet Dispersion Stability
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Solution Overview
Problem
Water-based white ink dispersions for inkjet applications face dispersion instability due to aggregation and sedimentation of high-density titanium oxide pigments, which is overcome by using low effective density titania pigments with reduced porosity, allowing for improved opacity and jetting performance.
Innovation Solution
The method involves synthesizing low effective density titanium oxide (TiO2) pigments by introducing porosity into the particles, using polymer templates or oxygen bubbles as templates, and calcining at high temperatures to reduce the density from above 4 to between 2.5 and 3.8, thereby enhancing dispersion stability and jetting performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If high-density titanium oxide pigments are used in water-based white ink dispersions, then the opacity is improved, but dispersion instability occurs due to aggregation and sedimentation
Solution Approach 1:
The patent applies porous materials by introducing controlled porosity into titanium oxide pigment particles. The porous structure reduces the effective density of the pigment particles from above 4 g/cm³ to between 2.5 and 3.8 g/cm³, which prevents sedimentation while maintaining opacity. The porosity is created through templating methods using polymer templates or oxygen bubbles during synthesis, followed by calcination to remove the templates and form the porous structure.
Solution Approach 2:
The patent changes the physical parameters of the titanium oxide pigment particles by controlling their density and size. Specifically, the effective density is reduced from above 4 g/cm³ to between 2.5 and 3.8 g/cm³, and the particle size is controlled to be between 100-300 nm. These parameter changes improve both dispersion stability and jetting performance while maintaining adequate opacity for white printing applications.
2Stability of the object's composition
If pigment particle size is reduced to improve dispersion stability, then jetting performance is improved, but opacity decreases
Solution Approach 1:
The porous structure compensates for the reduced particle size by creating a lower effective density. This allows the use of smaller particles (100-300 nm) for improved jetting and dispersion stability while the porous nature maintains light scattering properties necessary for opacity. The porosity creates a density mismatch that enhances suspension stability even at reduced particle sizes.
3Stability of the object's composition
If porosity is introduced to reduce density and improve dispersion stability, then jetting performance is improved, but manufacturing complexity increases
Solution Approach 1:
The patent applies preliminary action by incorporating the porosity creation step into the pigment synthesis process itself. Polymer templates or oxygen bubbles are introduced during the formation of titanium oxide particles, and the porosity is established through calcination as part of the synthesis sequence. This integrated approach avoids the need for separate porosity introduction steps and simplifies the overall manufacturing process.
Solution Approach 2:
The porous structure is created through a standardized synthesis protocol involving template addition, calcination, and controlled atmosphere processing. This established methodology, while adding steps to the synthesis process, provides consistent and reproducible results that justify the manufacturing complexity through improved product performance and stability.
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 low effective density TiO2 pigments achieve improved dispersion stability and opacity, with no visual sedimentation and reliable jetting performance, maintaining constant particle size over 45 days and achieving high opacity and drop velocity in thermal inkjet printheads.
Implementation Method 1
introducing porosity into the particles, using polymer templates or oxygen bubbles as templates, and calcining at high temperatures to reduce the density from above 4 to between 2.5 and 3.8
Implementation Method 2
calcining at high temperatures to reduce the density from above 4 to between 2.5 and 3.8
Implementation Method 3
Water-based white ink dispersions for inkjet applications face dispersion instability due to aggregation and sedimentation of high-density titanium oxide pigments
Data Source
AI summary
A method for manufacturing low effective density TiO2 includes providing a template having a surface. The template surface is coated with a titanium-containing compound that can be reduced to TiO2 at high temperature. The template is removed, thereby forming porous TiO2 particles. The effective density of the porous TiO2 particles is less than 4.