BaSO4 White Aqueous Inkjet Ink for Stable Opacity

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Solution Overview

Problem

Current white aqueous inkjet inks face challenges such as sedimentation of titanium dioxide nanoparticles, leading to reduced optical density and print opacity, and regulatory concerns due to the use of TiO2, which necessitates a safe and non-toxic pigment replacement.

Innovation Solution

Employing barium sulfate (BaSO4) pigment with a wide particle size distribution (Span ≥ 0.75) to formulate a stable, non-sedimenting white aqueous inkjet ink that achieves desired whiteness and opacity without TiO2, utilizing a broad particle size distribution to enhance light reflection and scattering.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If TiO2 pigment is used to achieve whiteness and opacity, then print quality is improved, but sedimentation occurs and long-term colloidal stability deteriorates

Engineering Contradiction:
Improvewhiteness and opacityVSAvoidcolloidal stability
Core Design Contradiction:
Illumination intensityVSStability of the object's composition

Solution Approach 1:

The patent changes the particle size parameter of the TiO2 pigment, specifically using a Dv50 between 0.5-2.0 micrometers and controlling the particle size distribution with Span≥0.75. This parameter optimization prevents sedimentation while maintaining whiteness and opacity, resolving the contradiction between print quality and colloidal stability.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite ink formulation combining TiO2 pigment with specific binders, dispersants, and surfactants. This composite approach enhances the colloidal stability of the pigment suspension while preserving its optical properties, thereby maintaining both print quality and long-term stability.

Inventive Principle:
Principle #40Composite materials

2Illumination intensity

If TiO2 pigment is used to achieve desired color characteristics, then whiteness is improved, but safety and toxicity concerns worsen

Engineering Contradiction:
ImprovewhitenessVSAvoidtoxicity
Core Design Contradiction:
Illumination intensityVSObject-affected harmful factors

Solution Approach 1:

The patent employs readily available TiO2 pigment with controlled particle characteristics that balances performance and safety. By optimizing particle size and distribution, the patent achieves effective whiteness at lower pigment concentrations, reducing overall exposure and associated toxicity concerns.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The patent modifies the physical parameters of TiO2 (particle size Dv50: 0.5-2.0 micrometers, Span≥0.75) to achieve optimal whiteness with minimized health risks. These parameter changes allow effective performance at reduced pigment loading, thereby lowering toxicity exposure.

Inventive Principle:
Principle #35Parameter changes

3Illumination intensity

If high TiO2 loading is used to achieve desired color characteristics, then whiteness and opacity are improved, but pigment loading and cost increase

Engineering Contradiction:
Improvewhiteness and opacityVSAvoidpigment loading
Core Design Contradiction:
Illumination intensityVSQuantity of substance

Solution Approach 1:

The patent optimizes TiO2 particle size parameters (Dv50: 0.5-2.0 micrometers, Span≥0.75) to maximize light scattering efficiency. This enables achievement of desired whiteness and opacity at lower pigment loadings, reducing both material quantity and associated costs.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent formulates a composite ink system with TiO2 pigment, binders, dispersants, and surfactants that enhances pigment efficiency. This composite approach achieves optimal whiteness and opacity with reduced TiO2 content, lowering both pigment loading and formulation costs.

Inventive Principle:
Principle #40Composite materials

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 BaSO4 pigment-based inkjet ink provides stable, non-sedimenting performance, achieving or exceeding the whiteness and opacity of TiO2-based inks at lower pigment loadings, ensuring safe and effective print quality.

Implementation Method 1

utilizing a broad particle size distribution to enhance light reflection and scattering

Methodology Applied
Scientific EffectLight scattering: Scattering

Implementation Method 2

utilizing a broad particle size distribution to enhance light reflection and scattering

Methodology Applied
Scientific EffectLight reflection: Reflection

Data Source

PatentUS12503615B2White aqueous inkjet ink
Publication Date: 2025.12.23 XEROX CORP

AI summary

An aqueous inkjet ink composition including water; an optional co-solvent; an optional dispersant; an optional resin; an optional wax; and a BaSO4 pigment; wherein a particle size distribution is defined as Span=(Dn90−Dn10)/(Dn50); and wherein the BaSO4 pigment has a wide particle size distribution wherein the Span is 0.75 or greater.