Titanium Dioxide Pigment Dispersion for Opaque Inkjet Printing
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Solution Overview
Problem
Existing aqueous dispersions and inkjet ink compositions with titanium dioxide particles face stability issues due to particle settling and inadequate light scattering, as particles larger than 200 nm do not form stable dispersions and fail to effectively scatter actinic light for opaque images.
Innovation Solution
The use of a dispersing polymer, such as a hexyloxy benzoic acid polymer or a polymer prepared from the Diels Alder adduct of 3-maleimidopropionic acid and furfuryl (meth)acrylate, is employed to maintain titanium dioxide particles in a stable, finely dispersed state within an aqueous medium, ensuring a weight ratio of pigment to polymer from 19:1 to 2:1, along with a humectant of molecular weight less than 1,000, to achieve effective inkjet printing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If titanium dioxide particles with size of 200 nm to 1000 nm are used for efficient light scattering, then light scattering efficiency is improved, but dispersion stability deteriorates due to particle settling
Solution Approach 1:
The patent applies parameter changes by using titanium dioxide particles in the specific size range of 200-1000 nm (optimizing the particle size parameter) while simultaneously adjusting the dispersant concentration and type to maintain dispersion stability. This resolves the contradiction by finding the optimal parameter combination that achieves both efficient light scattering and stable dispersion.
Solution Approach 2:
The patent introduces dispersants as intermediary substances that mediate between the titanium dioxide particles and the aqueous medium. These dispersants adsorb onto the particle surfaces, providing steric or electrostatic repulsion that prevents settling while allowing the particles to maintain their light-scattering size range.
2Illumination intensity
If titanium dioxide particles larger than 200 nm are used, then light scattering for opaque images is improved, but inkjet printing clogging increases
Solution Approach 1:
The patent optimizes the particle size parameter to fall within the 200-1000 nm range, which is large enough to provide effective light scattering for opacity but small enough to prevent clogging of inkjet nozzles. This parameter optimization resolves the contradiction between opacity and printing reliability.
Solution Approach 2:
The patent uses titanium dioxide particles that replicate the optimal size characteristics needed for both functions: they are large enough to scatter light effectively (providing opacity) but small enough to flow through inkjet nozzles without clogging, essentially copying the ideal particle size requirements for dual functionality.
3Illumination intensity
If titanium dioxide particles with high density are used for opacity, then light scattering is improved, but settlement rate increases
Solution Approach 1:
The patent introduces dispersants as intermediary substances that counteract the gravitational settling tendency of high-density titanium dioxide particles. These dispersants adsorb onto particle surfaces and provide repulsive forces that balance the settling tendency, allowing the particles to remain suspended while maintaining their light-scattering properties.
Solution Approach 2:
The patent applies the anti-weight principle by using dispersants that provide an opposing force to gravity's effect on the dense titanium dioxide particles. The dispersant layer creates steric or electrostatic repulsion that counterbalances the gravitational settling, effectively neutralizing the harmful effect of high particle density.
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
This approach results in stable aqueous dispersions and inkjet ink compositions that maintain particle sizes below 200 nm, enabling successful actinic light scattering and the formation of opaque, high-opacity images on substrates during inkjet printing.
Implementation Method 1
aqueous dispersions including colorant particles such as titanium dioxide particles
Implementation Method 2
maintain titanium dioxide particles in a stable, finely dispersed state
Implementation Method 3
such particles in this size range or larger do not form stable aqueous dispersions and will readily settle out... efficient at scattering actinic light
Data Source
AI summary
An aqueous dispersion contains pigment colorant particles that are present in an amount of at least 5 weight % and up to and including 80 weight %; a dispersing polymer that either is a hexyloxy benzoic acid polymer or a polymer that is prepared from the Diels Alder adduct of 3-maleimidopropionic acid and furfuryl (meth)acrylate; and an aqueous medium. The weight ratio of the pigment colorant particles to the dispersing polymer is from 19:1 to and including 2:1. These aqueous dispersions can be incorporated into aqueous inkjet ink compositions that can be used for forming opaque images such as white images using various inkjet printing methods such as continuous inkjet printing methods.