Irreversibly Erasable Ink Composition Using Polyether Amine Decolorization
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Solution Overview
Problem
Existing thermochromic ink compositions that undergo irreversible decolorization lack effective decolorization agents capable of completely eliminating the color change effect after a temperature change, leading to unstable color impressions.
Innovation Solution
A thermochromic ink composition incorporating core-shell microcapsules with a polyether amine decolorization agent, which has a specific molecular weight and carbon-to-oxygen ratio, is used to irreversibly decolor the colorant formed by electron transfer reactions between electron-donative and electron-accepting compounds, ensuring complete discoloration upon temperature changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional decolorization agents (e.g., tetraethylene pentamine, pentaethylene hexamine) are used, then the ink composition can undergo decolorization, but the decolorization is incomplete and the color impression remains unstable
Solution Approach 1:
The patent changes the chemical parameters of the decolorization agent by selecting polyether amines with specific molecular weights (150-2000 g/mol) and carbon-to-oxygen ratios (2:1 to 5:1). These parameter changes optimize the agent's ability to penetrate microcapsules and react with the color-forming compounds, achieving complete and stable decolorization that conventional agents cannot accomplish.
Solution Approach 2:
The patent uses a composite approach by combining the polyether amine decolorization agent with core-shell microcapsules containing electron-donative and electron-accepting compounds. This composite system ensures that the decolorization agent can effectively interact with the thermochromic components while maintaining stability during storage, resolving the contradiction between stability and decolorization effectiveness.
2Productivity
If the decolorization agent has high basicity to achieve rapid decolorization, then the color change effect is eliminated, but the storage stability of the color impression deteriorates
Solution Approach 1:
The patent optimizes the basicity parameter of the decolorization agent by using polyether amines with controlled molecular weights and structures. These agents have sufficient basicity to rapidly decolorize the thermochromic ink upon heating, but their specific structural parameters prevent premature reaction during storage, thus achieving both rapid decolorization and storage stability.
Solution Approach 2:
The polyether amine acts as an intermediary that requires thermal activation to become effective. During storage at normal temperatures, the agent remains dormant and does not interfere with the color-forming compounds. Upon heating, the increased molecular mobility allows the agent to penetrate the microcapsules and rapidly decolorize the ink, thus mediating between storage stability and decolorization speed.
3Ease of manufacture
If the molecular weight of the decolorization agent is low to enhance penetration and decolorization ability, then the decolorization effectiveness improves, but the agent may become too volatile or unstable
Solution Approach 1:
The patent identifies an optimal parameter range for the molecular weight of polyether amine decolorization agents (150-2000 g/mol). Within this range, the agents have sufficient low molecular weight to penetrate the microcapsule shells and react with color-forming compounds, while maintaining adequate stability and reduced volatility. The carbon-to-oxygen ratio parameter (2:1 to 5:1) is simultaneously optimized to balance reactivity and stability.
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 thermochromic ink composition maintains a stable color impression during storage and rapidly discolores upon exposure to elevated temperatures, providing a clear and blue-less appearance, outperforming comparative agents in discoloration effectiveness.
Implementation Method 1
comprise an electron-donative organic compound and an electron-accepting compound which can undergo a chemical reaction that creates a colored reaction product
Implementation Method 2
The decolorization agent may be capable of irreversibly decoloring a colorant formed by the electron transfer reaction between the components (a) and (b). The decolorization agent may be a polyether amine
Implementation Method 3
The component (c) may cause or allow the color-forming electron transfer reaction between the components (a) and (b) above the melting point or softening point of the core component
Data Source
AI summary
There is a thermochromic ink composition having core-shell microcapsules, an aqueous dispersion medium and a decolorization agent.