Ink Jet Ink Polyurethane Polymer Ejection Stability
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Solution Overview
Problem
Conventional inkjet inks containing polyurethane polymers suffer from poor ink ejection stability, image deflection due to face wetting, and inadequate scratch and highlighter resistance, despite efforts to improve these characteristics.
Innovation Solution
The development of an inkjet ink using a polyurethane polymer with specific molecular weight and acid value ranges, combined with a pigment dispersed by a polymer other than the polyurethane polymer, to enhance ejection stability and image durability, while minimizing image deflection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a polyurethane polymer is used to disperse pigment, then image fastness (scratch resistance and highlighter resistance) is improved, but ink ejection stability deteriorates
Solution Approach 1:
The patent changes the chemical composition parameters of the polyurethane polymer by specifying the use of poly(tetramethylene glycol) as the polyol component and controlling the molecular weight to 400 or less. This parameter optimization achieves a balance between hydrophilicity (for ejection stability) and film-forming properties (for scratch resistance), resolving the contradiction between these two requirements.
Solution Approach 2:
The patent creates a composite system by combining the polyurethane polymer with specific surfactants and pigments. The polyurethane polymer provides the film-forming matrix for scratch resistance, while the surfactant system ensures proper wetting and ejection stability, achieving both requirements through material composition.
2Reliability
If a polyurethane polymer with high hydrophilicity is used, then ink ejection stability is improved, but color developability deteriorates
Solution Approach 1:
The patent optimizes the molecular weight parameter of the poly(tetramethylene glycol) to 400 or less, which provides sufficient hydrophilicity for stable ejection while maintaining adequate film-forming capability for color developability. This precise parameter control resolves the contradiction between hydrophilicity and color performance.
3Reliability
If a polyurethane polymer with short molecular chain polyol is used, then ink ejection stability is improved, but scratch resistance deteriorates
Solution Approach 1:
The patent specifies using poly(tetramethylene glycol) with molecular weight of 400 or less as the polyol component. This molecular weight optimization provides the right balance between chain flexibility (for ejection stability) and film strength (for scratch resistance), resolving the contradiction between these properties.
4Strength
If a polyurethane polymer with urea bonds is used, then adhesion is improved, but image deflection occurs due to face wetting
Solution Approach 1:
The patent modifies the chemical structure parameters by using poly(tetramethylene glycol) as the polyol and controlling the polymer composition to reduce excessive adhesion to the recording head face. This parameter optimization maintains necessary adhesion for image fastness while preventing face wetting that causes image deflection.
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 achieves improved scratch resistance, highlighter resistance, and reduced image deflection, ensuring stable ink ejection and enhanced image quality.
Implementation Method 1
a pigment which is dispersed using a polymer other than the polyurethane polymer
Implementation Method 2
The ink has improved adhesion to a plastic film and improved laminate strength
Data Source
AI summary
An ink jet ink contains a polyurethane polymer and a pigment. The polyurethane polymer has units derived from a polyisocyanate, a polyether polyol having no acid group, and a diol having an acid group. The pigment is dispersed using a polymer other than the polyurethane polymer. The ratio of the percentage of the urethane bond in the polyurethane polymer to the percentage of the urea bond in the polyurethane polymer is 85.0/15.0 or more and 98.5/1.5 or less.