Water-Based Ink Composition for High Density and Wetting Spread
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Solution Overview
Problem
Existing inkjet inks face a trade-off between achieving high image density and wide line width due to the use of highly hydrophobic solvents, as surfactants fail to reduce surface tension, leading to poorer wetting spread.
Innovation Solution
A water-based ink formulation comprising a specific nonionic surfactant with a butylene oxide chain, a water-soluble solvent with an octanol/water partition coefficient of −1.0 to 0.4, and a pigment, which reduces dynamic surface tension while maintaining high image density and wetting spread.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If highly hydrophobic solvents are used to achieve high image density, then image density is improved, but wetting spread deteriorates due to inability to reduce surface tension
Solution Approach 1:
The patent changes the chemical parameters of the surfactant by specifying a particular structure with a butylene oxide chain (formula: R-CO-O-(CH2-CH2-O-CH2-CH2-O)n-H) and controlling the sum of ethylene oxide and butylene oxide units (5 ≤ n ≤ 20). This structural parameter change enables the surfactant to effectively reduce dynamic surface tension even in the presence of highly hydrophobic solvents, thereby improving wetting spread while maintaining image density.
Solution Approach 2:
The patent creates a composite ink formulation combining highly hydrophobic solvents (which provide high image density through pigment agglomeration) with a specifically structured nonionic surfactant (which provides wetting spread by reducing surface tension). This composite approach allows both functionalities to coexist and work together, resolving the trade-off between image density and wetting spread.
2Manufacturing precision
If highly hydrophobic solvents are used to achieve high image density, then image density is improved, but line width deteriorates due to poorer wetting spread
Solution Approach 1:
The patent modifies the surfactant structure parameters by specifying a butylene oxide chain component and controlling the total number of ether units (5 ≤ n ≤ 20). This parameter optimization allows the surfactant to effectively reduce dynamic surface tension, enabling better wetting spread and consequently achieving wider line width while preserving the high image density provided by hydrophobic solvents.
Solution Approach 2:
The ink formulation combines highly hydrophobic solvents (for high image density) with a specifically structured nonionic surfactant (for improved wetting and line width). This composite system allows simultaneous achievement of both high image density and wide line width by leveraging the complementary functions of its components.
3Ease of operation
If surfactant is added to reduce surface tension, then wetting spread is improved, but image density deteriorates when using highly hydrophobic solvents
Solution Approach 1:
The patent optimizes the surfactant molecular structure by introducing a butylene oxide chain and controlling the ether unit composition (5 ≤ n ≤ 20). This structural parameter change enhances the surfactant's ability to reduce dynamic surface tension while maintaining compatibility with highly hydrophobic solvents, thereby preventing pigment agglomeration disruption and preserving image density.
Solution Approach 2:
The specifically structured nonionic surfactant acts as an intermediary that bridges the hydrophilic and hydrophobic components of the ink system. It mediates between the water-based carrier and the highly hydrophobic solvents, enabling effective surface tension reduction and wetting spread without compromising the pigment-solvent interactions necessary for high image density.
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 both high image density and wide line width simultaneously by optimizing surfactant and solvent properties, ensuring dynamic surface tension is within a suitable range.
Implementation Method 1
a surfactant represented by the following general formula (1)... reduces dynamic surface tension while maintaining high image density and wetting spread
Implementation Method 2
High image density can be achieved by using a solvent formulation including many highly hydrophobic solvents and agglomerating pigments on the paper surface
Data Source
AI summary
An ink includes: a surfactant represented by the following general formula (1); a water-soluble solvent having a log Kow of −1.0 or more and 0.4 or less; a pigment; and water, a content of the water-soluble solvent being 30 mass % or more and 50 mass % or less.In the general formula (1), m and n indicate integers whose sum is 12 or more and 14 or less, x indicates an integer of 1 or more and 20 or less, and y indicates an integer of 1 or more and 10 or less.