Radiation Curable Ink Jet Composition with High Acid Value Dispersant
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Solution Overview
Problem
Radiation curable ink jet compositions face challenges with storage stability and ejection stability due to unintentional curing and generation of foreign materials when moisture is present, particularly with hindered amine compounds that have hydrophilic groups, leading to increased viscosity and degradation of ejection stability.
Innovation Solution
A radiation curable ink jet composition comprising a dispersant with an acid value of 30 mgKOH/g or more, a polymerizable compound, and a hindered amine compound represented by specific general formulas, which maintains low viscosity and inhibits radical trapping even in moist environments, preventing protonation of the nitroxy radical and thus stabilizing the ink.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a hindered amine compound with hydrophilic groups is used to improve storage stability, then the ink is more stable against unwanted polymerization, but the ink becomes soluble in moisture and reacts, leading to foreign material generation and viscosity increase
Solution Approach 1:
The patent changes the chemical structure parameters of the hindered amine compound by specifying general formulas (1) and (2) with particular substituents, and controls the acid value parameter of the dispersant to be 30 mgKOH/g or more. These parameter changes ensure the compound remains insoluble in moisture while maintaining radical trapping capability.
Solution Approach 2:
The patent introduces a dispersant with specific acid value as an intermediary substance that mediates between the hindered amine compound and moisture. The dispersant with acid value of 30 mgKOH/g or more prevents the hindered amine compound from reacting with moisture while maintaining the stability of the ink composition.
2Reliability
If the nitroxy radical of the hindered amine compound traps a proton in acidic conditions, then the compound is converted to a secondary amine, but this causes precipitation of foreign materials and increases viscosity, degrading ejection stability
Solution Approach 1:
The patent changes the chemical structure parameters by using hindered amine compounds with specific general formulas (1) and (2) that have lower protonation susceptibility, and controls the overall acidity parameter of the ink composition through the dispersant selection. This prevents the nitroxy radical from trapping protons and forming secondary amines that cause precipitation.
3Ease of operation
If the ink jet composition has low viscosity for stable ejection, then the ejection process is stable, but the composition may be more susceptible to moisture-related reactions
Solution Approach 1:
The patent creates a composite ink composition combining a dispersant with acid value of 30 mgKOH/g or more, a polymerizable compound, and a hindered amine compound with specific structure. This composite formulation maintains low viscosity for stable ejection while the specific components work together to prevent moisture-related reactions and maintain storage 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 composition ensures stable ejection and storage stability by maintaining low viscosity and preventing foreign material generation, even in humid conditions, thereby enhancing the performance of the ink jet recording process.
Implementation Method 1
The hindered amine compound having the structure as described above inhibits an unfavorable polymerization by trapping a radical with a nitroxy group
Implementation Method 2
the dispersant has an acid value of 30 mgKOH/g or more... the nitroxy radical of the hindered amine compound traps a proton and is changed into a compound
Implementation Method 3
a radiation curable ink jet composition... unintentional curing
Data Source
AI summary
A radiation curable ink jet composition contains: a dispersant; a polymerizable compound; and a hindered amine compound represented by the following general formula (1) or (2), the radiation curable ink jet composition has a viscosity of 50 mPa·s or less at 25° C., and the dispersant has an acid value of 30 mgKOH/g or more,In the formula (1), R1 represents H—, O═, or R2—CO—, and R2 represents an alkyl group having 1 to 6 carbon atoms or a substituted or unsubstituted aromatic ring,In the formula (2), R3 represents —OCO—R4—COO—, and R4 represents an alkyl group having 1 to 12 carbon atoms.