Polyurethane Ink Antioxidant Stabilization
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Solution Overview
Problem
Ink jet inks with polyurethane polymers and self-dispersion carbon black face issues with long-term image fastness and ejection stability, particularly when stored for extended periods and used in high-speed recording methods, due to molecular weight reduction and carbon black aggregation.
Innovation Solution
The ink formulation includes a polyurethane polymer with specific acid value ranges and antioxidants represented by general formulae (1) to (3), which stabilize the molecular weight and prevent carbon black aggregation, ensuring high fastness and ejection stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a polyurethane polymer with polyether polyol is used in ink, then image fastness is improved, but ejection stability deteriorates during high-speed recording
Solution Approach 1:
The patent changes the chemical parameters of the polyurethane polymer by specifying the acid value range (40-140 mg KOH/g) and the type of diol used (with acid group). This parameter optimization allows the polymer to maintain both image fastness and ejection stability, resolving the contradiction between these two properties.
Solution Approach 2:
The patent creates a composite ink formulation combining polyurethane polymer with specific antioxidants (formulae 1-3) and carbon black. This composite approach enhances both image fastness through the polymer structure and ejection stability through the antioxidant protection, preventing degradation during high-speed recording.
2Duration of action of stationary object
If BHT antioxidant is added to improve storage stability, then image fastness during storage is improved, but ejection stability deteriorates at high recording speeds
Solution Approach 1:
The patent changes the antioxidant component from BHT to compounds with specific chemical structures (formulae 1-3). This parameter change in antioxidant selection provides both long-term storage stability and maintains ejection stability during high-speed recording, resolving the contradiction between storage durability and recording performance.
Solution Approach 2:
The patent introduces a specific class of antioxidants (formulae 1-3) as intermediary substances that mediate between the polyurethane polymer and carbon black, preventing their degradation during both storage and high-speed recording. These antioxidants act as protective intermediaries that maintain system stability across different operational conditions.
3Duration of action of moving object
If ink is stored for long period, then availability is improved, but image fastness deteriorates due to molecular weight reduction
Solution Approach 1:
The patent applies preliminary protective action by incorporating antioxidants (formulae 1-3) into the ink formulation before storage. These antioxidants preemptively prevent molecular weight reduction of the polyurethane polymer during long-term storage, thereby maintaining image fastness even after extended storage periods.
Solution Approach 2:
The patent converts the potential harmful effect of long-term storage (which would cause polymer degradation) into a beneficial outcome by using antioxidants that actively prevent degradation. The storage period, which would normally harm image fastness, is transformed into a non-degradative period through the protective antioxidant system.
4Productivity
If recording is conducted at high speed, then productivity is improved, but ejection stability deteriorates due to carbon black aggregation
Solution Approach 1:
The patent introduces antioxidants (formulae 1-3) as intermediary substances that prevent carbon black aggregation during high-speed recording. These antioxidants act as protective intermediaries between the carbon black particles and the thermal energy, maintaining dispersion stability and ejection reliability even at high recording speeds.
Solution Approach 2:
The patent optimizes the chemical composition parameters of the ink by selecting specific antioxidants with particular molecular structures (formulae 1-3). This parameter optimization prevents carbon black aggregation during high-speed ejection, maintaining both productivity and ejection stability simultaneously.
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 excellent image fastness and high ejection stability even after long-term storage and during high-speed recording, preventing molecular weight reduction and carbon black deposition on recording head components.
Implementation Method 1
an ink containing a self-dispersion carbon black and a polyurethane polymer which contains a polyether polyol as a constituent component... the ink containing the self-dispersion carbon black and the polyurethane polymer having the polyether polyol as a constituent unit causes a change in the fastness of the resulting image before and after long-term storage
Implementation Method 2
an ink jet recording method in which an ink is ejected from a recording head by causing thermal energy to act on the ink
Data Source
AI summary
The invention provides an ink containing a polyurethane polymer which has units respectively derived from a polyisocyanate, a polyether polyol having no acid group and a diol having an acid group and has an acid value of 40 mg KOH/g or more and 140 mg KOH/g or less, a carbon black and at least one antioxidant selected from compounds represented by the general formulae (1) to (3).