Surface-Modified Metal Pigment Inkjet Composition for Stable Ejection
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Solution Overview
Problem
Existing ink jet ink compositions containing metal pigments suffer from inadequate gloss, ejection consistency, and storage stability, particularly when used at high temperatures or over extended periods, and there is a need for environmentally friendly components that maintain high metallic luster.
Innovation Solution
The ink jet ink composition includes scale-like metal pigments surface-treated with specific surface treatment agents, such as compounds with phosphate or phosphonate groups, and a liquid medium, ensuring a volume average particle size and shape ratios that enhance gloss and ejection consistency while maintaining stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If metal pigment is used in ink jet composition, then metallic luster is improved, but ejection consistency and storage stability deteriorate due to aggregation
Solution Approach 1:
A surface treatment agent comprising phosphate or phosphonate compounds is introduced as an intermediary between the metal pigment particles and the ink jet composition medium. This surface treatment agent chemically binds to the metal pigment surface, providing steric and electrostatic stabilization that prevents aggregation while maintaining metallic luster, thereby resolving the contradiction between luster and ejection consistency
Solution Approach 2:
The particle size parameters of the metal pigment are precisely controlled with a volume average particle size D50 of 1.0 µm or less and a D50/Z ratio of 17 or more. This parameter optimization ensures the particles are small enough to eject consistently through ink jet nozzles while maintaining the scale-like morphology necessary for metallic luster, resolving the contradiction between luster and ejection performance
2Reliability
If metal pigment particles are reduced in size for better ejection, then ejection consistency is improved, but gloss deteriorates
Solution Approach 1:
The particle size parameters are precisely optimized with D50 of 1.0 µm or less and D50/L ratio of 0.050 or less, ensuring particles are small enough for consistent ejection while maintaining sufficient size and scale-like morphology for gloss. This controlled parameter change resolves the contradiction between ejection consistency and gloss
Solution Approach 2:
The metal pigment particles are surface-modified with phosphate or phosphonate-containing compounds to create a composite structure. This composite material approach maintains the scale-like particle morphology necessary for gloss while the surface treatment prevents aggregation, enabling both good ejection consistency and high gloss to coexist
3Stability of the object's composition
If surface treatment is applied to metal pigment, then storage stability is improved, but ejection performance deteriorates due to added complexity
Solution Approach 1:
The surface treatment agent is selected and dosed to provide optimal stabilization without excessive viscosity increase or particle aggregation. The phosphate/phosphonate compounds form monolayer or controlled multilayer coatings that prevent aggregation during storage but do not interfere with ejection performance, resolving the contradiction between storage stability and ejection performance
Solution Approach 2:
The surface treatment agent acts as a mediator that provides steric and electrostatic stabilization during storage while being sufficiently thin and compatible with the ink jet medium to not interfere with ejection. This intermediary layer prevents aggregation during storage but allows consistent ejection, resolving the contradiction between storage stability and ejection performance
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 achieves improved gloss, ejection consistency, and storage stability, even under high-temperature conditions, with environmentally friendly components, and supports high-quality printed products.
Implementation Method 1
the metal pigment is surface-modified with a surface treatment agent. The surface treatment agent contains at least one selected from the group consisting of compounds represented by the following formula (1) and compounds represented by the following formula (2)
Data Source
Figure 1~2
AI summary
An ink jet ink composition contains a metal pigment and at least one liquid medium selected from the group consisting of organic solvents and water. The metal pigment is surface-modified with a surface treatment agent. The metal pigment is in the form of scale-like particles and has a volume average particle size D50 of 1.0 µm or less. The ratio D50/Z of the volume average particle size D50 of the metal pigment to the average thickness Z of the metal pigment particles is 17 or more, and the ratio D50/L of the volume average particle size D50 to the nozzle diameter L of the ink jet head is 0.050 or less.