Water-Based Ink Redispersibility via Boric Acid Complexation
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Solution Overview
Problem
Water-based inks using phosphate group-modified self-dispersing pigments for ink jet recording face challenges with redispersibility, leading to issues in ejection stability when dried, and require improvement in optical density.
Innovation Solution
Incorporating boric acid, diglycolic acid, or a chelating agent into the water-based ink to enhance redispersibility and optical density, along with a calcium ion, which improves the ink's ability to maintain stability and achieve high optical density when used in ink jet recording.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If phosphate group-modified self-dispersing pigment is used to achieve high optical density, then optical density is improved, but redispersibility deteriorates
Solution Approach 1:
The patent introduces boric acid, diglycolic acid, or chelating agents as intermediary substances that mediate between the phosphate group-modified self-dispersing pigment and the water-based ink matrix. These intermediaries improve redispersibility by forming complexes with metal ions and enhancing the stability of the pigment dispersion, allowing the pigment to maintain high optical density while improving its redispersibility characteristics
Solution Approach 2:
The patent changes chemical parameters of the ink composition by adding specific compounds (boric acid, diglycolic acid, chelating agents) that alter the chemical environment around the phosphate group-modified self-dispersing pigment. This modifies the pigment's interaction with water and other ink components, improving redispersibility while preserving high optical density through optimized chemical bonding and dispersion characteristics
2Illumination intensity
If phosphate group-modified self-dispersing pigment is used to achieve high optical density, then optical density is improved, but ejection stability deteriorates
Solution Approach 1:
Boric acid, diglycolic acid, or chelating agents serve as intermediary substances that stabilize the pigment dispersion in the water-based ink. These intermediaries prevent pigment aggregation and maintain uniform distribution, ensuring stable ejection performance while preserving high optical density through improved pigment stability in the ink stream
Solution Approach 2:
The patent performs preliminary stabilization of the pigment dispersion by adding boric acid, diglycolic acid, or chelating agents before ink ejection. This preliminary action prevents pigment aggregation and maintains dispersion stability throughout the ink's residence in the ink-jet head and during ejection, ensuring consistent optical density and ejection stability
3Illumination intensity
If water-based ink is evaporated to dryness in ink flowing path to achieve high optical density, then optical density is improved, but redispersibility deteriorates
Solution Approach 1:
Boric acid, diglycolic acid, or chelating agents act as intermediary substances that remain in the ink and prevent pigment aggregation during evaporation. These intermediaries maintain pigment dispersion stability even when water evaporates, allowing the ink to achieve high optical density through concentrated pigment while maintaining redispersibility through the stabilizing effect of the intermediary compounds
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 addition of these components significantly improves the redispersibility and optical density of the water-based ink, ensuring stable ejection and high-quality recording performance even when the ink is heated in the ink-jet head.
Implementation Method 1
adding at least one selected from the group consisting of (a) an oxoacid obtainable by hydrating boric oxide, or a salt thereof, (b) a compound in which the respective alkylene groups of two alkylene carboxylic acid groups are bonded via O, S, SO, or SO2, or a salt thereof, and (c) a chelating agent
Implementation Method 2
redispersibility is solubility and dispersibility of a solid substance generated by evaporation of a water-based ink to dryness
Implementation Method 3
a coloring agent; water; and a water-soluble organic solvent. The coloring agent comprises a phosphate group-modified self-dispersing pigment
Data Source
Figure 1
Figure 2A~2C
AI summary
A water-based ink for ink jet recording, containing: a coloring agent; water; and a water-soluble organic solvent. The coloring agent contains a phosphate group-modified self-dispersing pigment. The water-based ink further contains at least one selected from the group consisting of boric acid, diglycolic acid, and a chelating agent.