UV-Curable Inkjet Ink Composition Charge Transfer Polymerization
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Solution Overview
Problem
Actinic energy radiation curable ink jet inks face challenges with viscosity stability, curing sensitivity, discharge stability, and weather resistance, particularly when stored for long periods and used on rigid substrates, due to issues with polymerization inhibition by oxygen, humidity, and limited material variations.
Innovation Solution
An actinic energy radiation curable ink jet ink composition containing specific polymerizable monomers with controlled charge differences and elemental ions (Fe, Co, Ca, Na, Mg, Al, Ti, Sn, Zn) within the range of 5.0 ppm to 100 ppm, which enhances viscosity stability and curing sensitivity while ensuring stability against acid and alkali effects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If charge transfer complex polymerization-based monomers are applied in actinic energy radiation curable ink jet inks, then curing sensitivity is improved, but viscosity stability deteriorates during long-term storage
Solution Approach 1:
The patent controls the charge difference parameter between donor and acceptor monomers to be within 0.24-0.46, which optimizes the charge transfer complex formation while maintaining viscosity stability. This parameter control resolves the contradiction by finding the optimal range that provides sufficient curing sensitivity without excessive viscosity change during storage.
Solution Approach 2:
The patent uses composite monomer systems combining electron-rich donor monomers and electron-poor acceptor monomers in specific ratios. This composite approach allows the system to achieve both good curing sensitivity through charge transfer complex formation and acceptable viscosity stability by balancing the interactions between different monomer components.
2Productivity
If CT polymerization-based compounds are used to improve curing speed, then productivity is improved, but manufacturing precision deteriorates due to insufficient storage stability
Solution Approach 1:
By controlling the charge difference parameter and elemental ion content within specific ranges, the patent achieves fast curing speeds while maintaining sufficient storage stability. This prevents viscosity changes that would otherwise cause droplet scattering and printing precision deterioration.
Solution Approach 2:
The patent uses maleimide derivatives as acceptor monomers that form stable charge transfer complexes with donor monomers. These maleimide-based systems replicate the fast curing characteristics of CT polymerization while providing better storage stability compared to other acceptor monomer systems.
3Adaptability or versatility
If radically polymerizable type ink jet ink is used for wide material selection, then adaptability is improved, but reliability worsens due to polymerization inhibition by oxygen
Solution Approach 1:
The patent combines electron-rich donor monomers with electron-poor acceptor monomers to form charge transfer complexes. This composite monomer system enables reliable polymerization by utilizing the charge transfer mechanism that is less susceptible to oxygen inhibition compared to conventional radical polymerization, while still allowing wide material selection flexibility.
Solution Approach 2:
The patent changes the polymerization mechanism from conventional radical polymerization to charge transfer complex polymerization by controlling the electronic parameters of the monomer components. This parameter change provides reliable curing even in the presence of oxygen while maintaining material selection flexibility.
4Reliability
If cationically polymerizable type ink jet ink is used to avoid oxygen inhibition, then reliability is improved, but cost increases due to limited material variations
Solution Approach 1:
The patent uses composite systems of donor and acceptor monomers that form charge transfer complexes. This approach provides reliability similar to cationic polymerization by avoiding oxygen inhibition, while maintaining adaptability through the wide selection of available donor and acceptor monomer types and their adjustable ratios.
Solution Approach 2:
The charge transfer complex polymerization system serves multiple functions: it provides reliability by resisting oxygen inhibition like cationic systems, while maintaining the material selection flexibility of radical systems. The universal applicability of donor-acceptor monomer combinations achieves both goals 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 composition achieves high-quality image formation with excellent viscosity stability, curing sensitivity, and weather resistance, even under low illuminance and on rigid substrates, by minimizing polymerization inhibition and ensuring stability across storage and outdoor exposure.
Implementation Method 1
there has been an attempt to apply a charge transfer complex polymerization reaction (abbreviated as a CT polymerization reaction) to an actinic energy radiation curable composition
Implementation Method 2
an actinic energy radiation curable ink jet ink which is cured with actinic energy radiation such as light after printing
Data Source
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AI summary
One of the purposes of the present invention is to provide an ultraviolet-ray-curablee inkjet ink composition which has excellent viscosity stability, curing sensitivity, ejection stability and weather resistance when stored for a long period and enables the formation of a high-quality image. An active-energy-ray-curable inkjet ink composition which contains at least two polymerizable monomers each having an unsaturated bond, wherein the maximum value of the difference in electric charge of carbon atoms that constitute the unsaturated bond in each of the at least two polymerizable monomers is 0.24 to 0.46 inclusive and the total content of ions of the elements Fe, Co, Ca, Na, Mg, Al, Ti, Sn and Zn is 5.0 to 100 ppm inclusive, or the difference in e value of the unsaturated double bond moiety in each of the at least two polymerizable monomers is 2.8 to 6 inclusive, and wherein a compound which is unpolymerizable and has a substituent capable of reacting with a nucleophilic agent or an acidic compound is contained.