Urethane Resin Ink for Ejection Stability and Highlighter Resistance
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Solution Overview
Problem
Pigment inks used in inkjet recording methods suffer from low highlighter resistance and irregular ejection stability due to the adhesion of urethane resin to the recording head, leading to poor image quality and ejection accuracy.
Innovation Solution
An aqueous ink with a urethane resin having a polyether polyol unit and acidic groups, where the acid value is between 40-140 mg KOH/g and the molar ratio of urethane bonds to urea bonds is 80.0/20.0 or more, is neutralized with an alkali metal ion and ammonium type ion, maintaining a neutralization ratio of 80% or more for acidic groups and 1-45% for ammonium type ions, to enhance stability and prevent adhesion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If urethane resin is added to pigment ink to improve highlighter resistance, then highlighter resistance is improved, but ejection stability and ejection accuracy deteriorate due to adhesion to the recording head
Solution Approach 1:
The patent applies parameter changes by precisely controlling the acid value of the urethane resin (30-150 mg KOH/g) and the molar ratio of urethane bonds to urea bonds (80:20 or more). These parameter adjustments optimize the balance between highlighter resistance and ejection stability, preventing adhesion to the recording head while maintaining image fastness.
Solution Approach 2:
The patent uses composite materials by combining urethane resin with specific chemical characteristics (acidic groups, polyether polyol units) with pigment particles. This composite approach creates an ink formulation that achieves both highlighter resistance through the urethane resin and prevents adhesion through the controlled acid value and bond ratio.
2Object-affected harmful factors
If urethane resin with high urea bond content is used to improve highlighter resistance, then highlighter resistance is improved, but irregular ejection occurs due to adhesion to the ejection orifice surface
Solution Approach 1:
The patent applies parameter changes by setting the molar ratio of urethane bonds to urea bonds at 80:20 or more. This specific parameter control reduces the urea bond content, thereby minimizing adhesion to the ejection orifice surface and preventing irregular ejection, while still maintaining sufficient highlighter resistance through the urethane resin structure.
3Object-affected harmful factors
If ink is stored for extended periods, then highlighter resistance is maintained, but irregular ejection develops over time due to progressive adhesion
Solution Approach 1:
The patent applies preliminary action by pre-adjusting the acid value and neutralization ratio during ink formulation. This preliminary optimization prevents adhesion issues from developing during storage, ensuring that ejection stability is maintained throughout the ink's shelf life and usage period.
Solution Approach 2:
The patent uses feedback by establishing specific parameter ranges (acid value 30-150 mg KOH/g, neutralization ratio 80% or more) that are optimized based on observed adhesion behavior. These feedback-driven parameter specifications ensure long-term ejection stability by preventing the progressive adhesion that occurs with extended storage.
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 improved highlighter resistance and sustained ejection stability over time, reducing irregular ejections and maintaining accurate ink droplet direction, resulting in higher-quality images.
Implementation Method 1
The acidic groups in the urethane resin are neutralized with an alkali metal ion and at least one ammonium type ion selected from ammonium ion and an organic ammonium ion
Data Source
AI summary
An aqueous ink for ink jet contains a urethane resin. The urethane resin has a unit derived from a polyether polyol and a unit containing an acidic group. The acid value of the urethane resin is 40 to 140 mg KOH/g. The molar ratio of urethane bonds/urea bonds is 80.0/20.0 or more. Some of the acidic groups in the urethane resin are neutralized with particular neutralizing agents.