Inkjet Ink Surfactant Formulation for Flyability and Rubfastness
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Solution Overview
Problem
Existing inkjet inks struggle to achieve both excellent flyability and rubfastness, with most formulations compromising on one property to enhance the other.
Innovation Solution
The inkjet ink comprises a pigment, a first surfactant represented by a specific general formula (I), a second surfactant represented by another specific general formula (II), and an aqueous medium that includes water and a specific organic solvent with an octanol/water partition coefficient within a specific range. This formulation optimizes the surface tension of the ink for improved flyability and rubfastness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the inkjet ink uses conventional surfactants and organic solvents to improve rubfastness, then the rubfastness of the formed image is enhanced, but the flyability deteriorates and satellite droplets are generated
Solution Approach 1:
The patent changes the chemical parameters of the surfactants by specifying precise structural formulas (Formula I and Formula II) with defined molecular weight ranges and compositional ratios. This parameter optimization allows the surfactants to provide adequate surface tension reduction for rubfastness while maintaining sufficient surface tension for flyability, resolving the contradiction between these two properties
Solution Approach 2:
The patent uses a composite surfactant system comprising two different surfactants with specific structural characteristics (Formula I and Formula II) in controlled weight ratios. This composite approach combines the advantages of different surfactant molecules to achieve both excellent flyability and rubfastness simultaneously, which cannot be achieved with single surfactants alone
2Reliability
If the inkjet ink maintains high surface tension to improve flyability, then the ink droplet remains intact during ejection, but the rubfastness of the formed image deteriorates
Solution Approach 1:
The patent optimizes the surface tension parameters through precise control of surfactant molecular structure (Formula I and Formula II) and their concentration ratios in the ink formulation. This parameter tuning enables the ink to maintain appropriate surface tension for flyability while ensuring sufficient surface tension reduction for adequate rubfastness
3Strength
If the inkjet ink uses surfactants to reduce surface tension for better rubfastness, then the ink adheres well to the recording medium, but the surface tension becomes too low and satellite droplets are generated
Solution Approach 1:
The patent changes the surfactant parameters by specifying exact molecular structures (Formula I and Formula II) and controlling their weight ratio and concentration in the ink. This parameter optimization ensures the surfactants reduce surface tension sufficiently for rubfastness while preventing excessive surface tension reduction that would cause satellite droplet generation during ejection
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 inkjet ink achieves excellent flyability by maintaining high surface tension during ejection and excellent rubfastness by reducing surface tension after landing, thereby forming clear and durable images.
Implementation Method 1
The inkjet ink includes a first surfactant and a second surfactant. The first surfactant is a compound represented by general formula (I). The second surfactant is a compound represented by general formula (II).
Implementation Method 2
An octanol/water partition coefficient Log Kow of the specific organic solvent is −1.80 or more and −1.00 or less.
Data Source
AI summary
An inkjet ink includes: a pigment; a first surfactant; a second surfactant; and an aqueous medium. The first surfactant is a compound represented by the following general formula (I). The second surfactant is a compound represented by the following general formula (II). The aqueous medium includes water and a specific organic solvent. An octanol/water partition coefficient Log Kow of the specific organic solvent is −1.80 or more and −1.00 or less. A content ratio of the first surfactant is 0.03 mass % or more and 0.35 mass % or less. A content ratio of the second surfactant is 0.03 mass % or more and 0.30 mass % or less.