Aqueous Ink Formulation for Freezing Stability and Gloss Clarity
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Solution Overview
Problem
Aqueous inks containing pigments like quinacridone and diketopyrrolopyrrole pigments face issues with gloss clarity and pigment aggregation when frozen, as the dispersion state becomes unstable due to the coexistence of resin dispersants and surfactants, leading to reduced image quality.
Innovation Solution
An aqueous ink formulation with specific ratios of quinacridone or diketopyrrolopyrrole pigments, a resin dispersant with an acid value of 150-200 mg KOH/g, a fluorinated surfactant, and water-soluble organic solvents with varying dielectric constants to maintain pigment dispersion and prevent aggregation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If a fluorinated surfactant is added to lower surface tension and improve wettability, then image uniformity and glossiness are improved, but gloss clarity deteriorates when using particular pigments like quinacridone and diketopyrrolopyrrole
Solution Approach 1:
The patent changes the chemical parameters of the surfactant by specifying a fluorinated surfactant with a perfluoroalkyl group of 6-18 carbon atoms and a specific HLB value range (12-20). This parameter optimization allows the surfactant to lower surface tension effectively while maintaining gloss clarity, resolving the contradiction between image uniformity and gloss clarity.
Solution Approach 2:
The patent creates a composite ink formulation combining particular pigments (quinacridone or diketopyrrolopyrrole), resin dispersant, fluorinated surfactant, and water-soluble organic solvent in specific proportions. This composite system synergistically improves both image uniformity and gloss clarity by balancing the properties of individual components.
2Stability of the object's composition
If resin dispersant and surfactant are used together to disperse pigment, then pigment dispersion is improved, but pigment aggregates after freezing due to unstable dispersion state
Solution Approach 1:
The patent introduces a water-soluble organic solvent as an intermediary substance that stabilizes the dispersion state of pigment particles. This intermediary prevents direct harmful interactions between the resin dispersant and surfactant that cause aggregation upon freezing, thereby maintaining pigment dispersion stability and preventing aggregation after freezing.
Solution Approach 2:
The patent optimizes the concentration parameters of each component: pigment (0.1-5.0%), resin dispersant (0.1-3.0%), fluorinated surfactant (0.01-0.5%), and water-soluble organic solvent (5.0-50.0%). These parameter adjustments create a balanced formulation that maintains stable dispersion throughout freezing and thawing cycles.
3Manufacturing precision
If aqueous ink is used for recording, then gloss clarity of dye ink images is achieved, but ink freezes under certain usage environments and transportation conditions
Solution Approach 1:
The patent adjusts the chemical composition parameters by incorporating a water-soluble organic solvent with specific dielectric constant (3.0-20.0) and adding fluorinated surfactant at optimized concentrations. These parameter changes lower the freezing point of the aqueous ink while preserving gloss clarity, allowing the ink to remain fluid in cooler environments.
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 excellent gloss clarity and prevents pigment aggregation even after freezing, ensuring stable image quality by optimizing the dispersion state and surface energy of the ink components.
Implementation Method 1
a silicone-containing surfactant or a fluorinated surfactant is added to lower the surface tension of an ink, and thus the wettability and permeability of the ink to a recording medium is improved
Implementation Method 2
an ink containing a resin-dispersed pigment in which a pigment is dispersed by a resin (resin dispersant)
Implementation Method 3
the water-soluble organic solvent contains a water-soluble organic solvent A having a dielectric constant of 40.0 or more
Data Source
AI summary
An ink jet aqueous ink including a pigment; a resin dispersant; a fluorinated surfactant; and a water-soluble organic solvent. The pigment comprises quinacridone pigments comprising C.I. Pigment Violet 19, Red 122, 202 or 209; solid solution pigments of two or more thereof; diketopyrrolopyrrole pigments comprising C.I. Pigment Red 254, 255 or 272; or C.I. Pigment Violet 23. The dispersant has an acid value of 150-200 mg KOH/g. The surfactant comprise a perfluoroalkyl ethylene oxide adduct having a C6 or lower perfluoroalkyl group. The solvent contains a water-soluble organic solvent A and B having a dielectric constant of 40.0 or more and 3.0-20.0, respectively. Content p of the pigment is 5.00 mass % or less. Content a of solvent A to content p is 2.0 or more. Content b of solvent B to content a is 0.6 or less. Content b to content f of the surfactant is 10.0 or more.