Actinic Curable Inkjet Ink Surface Energy Control
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Solution Overview
Problem
Actinic energy radiation curable inkjet methods face challenges in achieving high glossy images with flexible cured films due to issues with surface tension control and rapid curing monomers leading to low flexibility and unstable ejection.
Innovation Solution
The development of an actinic radiation curable inkjet ink with a specific surface free energy range of 30 to 50 mJ/m2 and a polar component range of 5 to 15 mJ/m2, utilizing alicyclic epoxy compounds and a photo polymerization initiator, which enhances ejection properties and sensitivity, and forms flexible images.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a monomer with rapid curing rate is used to achieve high sensitivity, then curing speed is improved, but flexibility of cured film deteriorates and ejection stability worsens
Solution Approach 1:
The patent uses a composite monomer system comprising both a rapid-curing monomer (e.g., glycidyl ether compounds) and a slow-curing monomer (e.g., oxetane compounds). This combination allows the rapid-curing component to provide high sensitivity and fast curing, while the slow-curing component maintains flexibility and prevents brittleness in the final cured film.
Solution Approach 2:
The patent optimizes the molecular weight and structural parameters of the monomers used. By selecting monomers with specific molecular weights (e.g., 100-500 for rapid-curing, 500-2000 for slow-curing) and appropriate functional groups, the system achieves both high curing speed and maintained flexibility through parameter control.
2Manufacturing precision
If surface tension of ink is simply defined to control dot shape, then some control is achieved, but gloss control especially in serial print method remains insufficient
Solution Approach 1:
The patent precisely controls the surface free energy parameters (γs = 20-50 mJ/m², γsp = 5-20 mJ/m²) of the cured ink layer by selecting monomers with appropriate polar and non-polar components. This parameter optimization ensures consistent gloss (50 or more at 90% printing ratio) and reliable overprintability in serial printing methods.
3Speed
If actinic energy radiation curable ink is used to achieve rapid drying and recording on non-absorptive media, then drying speed is improved, but odor control and application flexibility face challenges
Solution Approach 1:
The patent employs a composite ink formulation combining actinic radiation-curable monomers with specific surface free energy characteristics. This composite approach enables rapid curing on non-absorptive media while controlling odor through proper monomer selection, thereby expanding application flexibility across different printing fields.
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 inkjet ink achieves excellent ejection, high sensitivity, and the ability to form high glossy and flexible images, with a gloss value of 50 or more at a 90% printing ratio, while maintaining flexibility and preventing cracking or peeling.
Implementation Method 1
an actinic radiation curable inkjet ink comprising a photo polymerization initiator and a polymerizable monomer
Implementation Method 2
a surface free energy γs of an ink layer cured by an actinic radiation is in the range of 30 to 50 mJ/m2 and a polar component γsp is in the range of 5 to 15 mJ/m2
Data Source
AI summary
Provided is an actinic radiation curable inkjet ink capable of high sensitivity and high glossy image; and an image forming method utilizing the same. An actinic radiation curable inkjet ink comprising a photo polymerization initiator and a polymerizable monomer, wherein a surface free energy γs of an ink layer cured by an actinic radiation is in the range of 30 to 50 mJ/m2 and a polar component γsp is in the range of 5 to 15 mJ/m2; wherein γsd, γsp and γsh each represent a non-polar component, a polar component and a hydrogen bond component of a surface free energy of a solid surface based on Young-Fowkes Equation, provided that the surface free energy is represented by γs=γsd+γsp+γsh.