Oil-Based Magnetic Ink Dispersant System for Viscosity Control
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Solution Overview
Problem
Oil-based magnetic inks face challenges with high viscosity and storage stability, particularly when using magnetic pigments like cobalt-manganese ferrite, which can lead to aggregation and discharge faults in inkjet printing due to their high specific gravity and coercivity, and existing solutions do not adequately address these issues.
Innovation Solution
An oil-based magnetic ink formulation using a combination of two dispersants, one with only an acid value and the other with both acid and base values, to effectively interact with the magnetic pigment surface, maintaining stability and low viscosity even at high concentrations and temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If magnetic pigment concentration is increased to enable magnetic reading, then magnetic strength is improved, but viscosity increases and storage stability deteriorates
Solution Approach 1:
The patent introduces a specific dispersant as an intermediary substance between the magnetic pigment particles and the non-aqueous solvent. This dispersant mediates the interaction by adsorbing onto the pigment surface and providing steric or electrostatic repulsion, preventing aggregation while maintaining low viscosity even at high pigment concentrations required for magnetic reading
Solution Approach 2:
The patent changes the chemical parameters of the dispersant system by selecting a dispersant with specific molecular structure and surface properties that are compatible with the magnetic pigment surface. This parameter optimization allows the system to maintain stability at high pigment concentrations without requiring viscosity reduction
2Reliability
If magnetic pigment with high coercivity is used to improve magnetic characteristics, then magnetic strength is improved, but aggregation occurs leading to discharge faults
Solution Approach 1:
The dispersant acts as a protective intermediary layer around high-coercivity magnetic pigment particles, preventing direct particle-to-particle contact that would cause aggregation. This mediator maintains the magnetic properties of the high-coercivity pigment while preventing the aggregation that would lead to discharge faults in inkjet printing
Solution Approach 2:
The patent applies local quality by creating a localized protective environment around each magnetic pigment particle through the dispersant. The dispersant provides localized steric or electrostatic repulsion at the particle surface, allowing high-coercivity particles to maintain their magnetic strength without aggregating with neighboring particles
3Device complexity
If single dispersant is used to simplify formulation, then device complexity is reduced, but storage stability under high temperature deteriorates
Solution Approach 1:
The patent merges the functions of multiple dispersants into a single optimized dispersant molecule that combines the beneficial properties of both acid-type and base-type dispersants. This unified dispersant provides both electrostatic and steric stabilization mechanisms, achieving high-temperature storage stability while simplifying the formulation to a single dispersant component
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 ink achieves low viscosity and improved storage stability, enabling efficient magnetic reading and preventing inkjet nozzle discharge faults, while maintaining sufficient magnetic strength and legibility.
Implementation Method 1
a pigment dispersant A that has an acid value but has no base value, a pigment dispersant B that has an acid value and a base value
Implementation Method 2
a pigment dispersant A that has an acid value but has no base value, a pigment dispersant B that has an acid value and a base value
Data Source
AI summary
An oil-based magnetic ink can be provided that has low viscosity and improved storage stability. Specifically disclosed is an oil-based magnetic ink containing a magnetic pigment that contains a ferrite, a pigment dispersant A that has an acid value but has no base value, a pigment dispersant B that has an acid value and a base value, and a non-aqueous solvent. One example of the pigment dispersant A is at least one compound selected from the group consisting of hydroxystearic acid and polyhydroxystearic acid. One example of the pigment dispersant B has an acid value of at least 5 mgKOH/g.