Water-based Ink Drying via High-Boiling Solvent
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Solution Overview
Problem
Water-based inks for ink-jet recording face challenges in improving drying properties while minimizing odor and viscosity issues, particularly with the use of dipropylene glycol monopropyl ether (DPP), which volatilizes and emits odors.
Innovation Solution
A water-based ink formulation incorporating a water-insoluble liquid with a boiling point of at least 250 degrees Celsius, such as diethyl adipate or polypropylene glycol, is dispersed in the ink to enhance drying properties and reduce odor, while maintaining low viscosity and preventing unevenness in printed materials.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If dipropylene glycol monopropyl ether (DPP) is added to improve drying property, then drying speed is improved, but odor is generated due to volatilization
Solution Approach 1:
The patent changes the key parameter from using low-boiling-point solvents (DPP with boiling point around 212°C) to high-boiling-point solvents (boiling point 250°C or higher). This parameter change maintains the drying speed improvement while eliminating odor generation, as the high-boiling-point solvent does not volatilize at room temperature or typical printing temperatures.
Solution Approach 2:
The patent exploits the phase transition properties of solvents by selecting a high-boiling-point solvent that remains in liquid phase under normal operating conditions. This prevents the vaporization phase transition that causes odor, while still allowing the solvent to evaporate slowly from the printed medium to achieve drying.
2Speed
If dipropylene glycol monopropyl ether (DPP) is added to improve drying property, then drying speed is improved, but viscosity increases
Solution Approach 1:
The patent changes the molecular weight and chemical structure parameters of the solvent from DPP (molecular weight 176) to high-boiling-point solvents with optimized molecular structures. This parameter change achieves the desired drying speed while maintaining lower viscosity, as the high-boiling-point solvents have molecular structures that reduce ink formulation viscosity.
3Ease of manufacture
If conventional solvents are used, then ink formulation is simple, but unevenness occurs in printed matter
Solution Approach 1:
The patent changes the boiling point parameter to 250°C or higher, which fundamentally alters the evaporation characteristics of the solvent. This change prevents rapid surface drying that causes unevenness, allowing uniform ink penetration into the recording medium while maintaining relatively simple formulation procedures.
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 solution effectively improves drying properties, suppresses odor emission, and maintains low viscosity, resulting in uniform ink penetration and reduced discharge failures, with the specific water-insoluble liquid enhancing adaptability and surface tension for better ink permeability.
Implementation Method 1
a water-insoluble liquid which is dispersed in the water, and of which boiling point is not less than 250 degrees Celsius
Implementation Method 2
the DPP is volatilized and an odor is emitted... a water-insoluble liquid which is dispersed in the water, and of which boiling point is not less than 250 degrees Celsius
Data Source
AI summary
A water-based ink for ink-jet recording contains a water-soluble colorant; water; and a water-insoluble liquid which is dispersed in the water and of which boiling point is not less than 250 degrees Celsius. The water-based ink may further contain a surfactant. The drying property of the water-based ink is improved and any odor can be lowered.