Ink Jet Pigment Ink Dispersion Stability via Pseudo-Microencapsulation
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Solution Overview
Problem
Ink jet recording aqueous pigment inks face challenges with dispersion stability and sedimentation of self-dispersing pigments due to aggregation, leading to issues with color reproduction, print density, and reliability.
Innovation Solution
The use of an ink jet recording aqueous pigment ink containing a self-dispersing pigment, a quaternary amino acid, a non-polymeric, nonionic material with a melting point of 40° C. or more, and at least one of trialkylamine or trialkanolamine, which forms a pseudo-microencapsulated structure to enhance dispersion stability and prevent sedimentation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If self-dispersing pigment is used without dispersant, then waterfastness and light fastness are improved, but dispersion stability deteriorates due to aggregation and sedimentation
Solution Approach 1:
A non-polymeric, nonionic material with melting point of 40°C or more is introduced as an intermediary substance between the self-dispersing pigment and the ink vehicle. This material forms a protective interface that prevents direct aggregation of pigment particles while maintaining the self-dispersing characteristics, thereby resolving the contradiction between using dispersant-free pigment and achieving stable dispersion.
Solution Approach 2:
The melting point parameter of the nonionic material is specifically set at 40°C or more to optimize its functionality. This parameter change ensures the material remains stable at room temperature while providing adequate thermal energy to maintain dispersion stability in the ink formulation, preventing both aggregation and sedimentation.
2Manufacturing precision
If pigment concentration is increased to improve print density, then color reproduction is improved, but sedimentation increases due to aggregation
Solution Approach 1:
The non-polymeric, nonionic material acts as a spacer and protective layer around pigment particles, enabling higher pigment concentrations to be maintained without aggregation. This intermediary structure allows increased print density while preventing the sedimentation that would normally occur at higher concentrations.
3Reliability
If ink viscosity is reduced to improve ejection stability, then inkjet printing reliability is improved, but pigment aggregation may increase
Solution Approach 1:
The melting point parameter of the nonionic material (40°C or more) is optimized to provide thermal stability that maintains pigment dispersion even at lower viscosities. This parameter control allows the ink to maintain low viscosity for good ejection while the nonionic material prevents pigment aggregation through its protective interface.
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 solution effectively stabilizes the dispersion of self-dispersing pigments, preventing aggregation and sedimentation, thereby improving color developability and ejection stability while maintaining low viscosity, ensuring high-quality inkjet printing.
Implementation Method 1
a non-polymeric, nonionic material having a melting point of 40° C. or more, and at least one of trialkylamine and trialkanolamine, which forms a pseudo-microencapsulated structure to enhance dispersion stability and prevent sedimentation
Implementation Method 2
The content of the non-polymeric, nonionic material is 3% to 15% by mass relative to the total mass of the ink jet recording aqueous pigment ink
Data Source
AI summary
An ink jet recording aqueous pigment ink contains a self-dispersing pigment, a quaternary amino acid, a non-polymeric, nonionic material having a melting point of 40° C. or more, and at least one of trialkylamine and trialkanolamine. The content of the non-polymeric, nonionic material is 3% to 15% by mass relative to the total mass of the ink jet recording aqueous pigment ink.