Radiation Curable Ink Set Adhesion Wet Spreadability
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Solution Overview
Problem
Ink jet recording methods face challenges in achieving optimal adhesion and wet spreadability of radiation curable inks, particularly when a large amount of monofunctional polymerizable compounds are used in the under layer, as it compromises the wet spreadability of the over layer ink, even with adjustments in surface tension.
Innovation Solution
An ink set comprising an under layer ink with 80.0% or more monofunctional polymerizable compounds and 55.0% or more polymerizable compounds with a nitrogen heterocyclic structure or hydroxy group, along with an over layer ink, where the under layer ink contains specific monomers like vinyl ether group-containing (meth)acrylate esters, and the over layer ink has a higher content of monofunctional polymerizable compounds, improving adhesion and wet spreadability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a large amount of monofunctional polymerizable compound is blended in the under layer ink to improve adhesion, then adhesion of the coating film to recording medium is improved, but wet spreadability of the over layer ink deteriorates
Solution Approach 1:
The patent applies local quality by differentiating the functional characteristics of polymerizable compounds between the under layer and over layer inks. The under layer ink contains monofunctional polymerizable compounds (80.0% or more) specifically for adhesion to the recording medium, while the over layer ink contains polyfunctional polymerizable compounds (55.0% or more) specifically for wet spreadability and coverage. This localized functional assignment resolves the contradiction by preventing the over layer ink from having poor wet spreadability while maintaining the under layer's adhesion enhancement.
Solution Approach 2:
The patent employs parameter changes by precisely controlling the composition ratios of polymerizable compounds in each ink layer. The under layer ink is formulated with 80.0% or more monofunctional polymerizable compounds, while the over layer ink is formulated with 55.0% or more polyfunctional polymerizable compounds. This parameter optimization allows the system to achieve both adhesion and wet spreadability by adjusting the chemical composition parameters of each layer independently.
2Ease of operation
If polyfunctional polymerizable compounds are used in the under layer to improve wet spreadability, then wet spreadability of the over layer ink is improved, but adhesion of the coating film to recording medium deteriorates
Solution Approach 1:
The patent applies local quality by assigning different polymerizable compound types to different layers based on their specific functions. The under layer ink uses monofunctional polymerizable compounds (80.0% or more) that provide strong adhesion to the recording medium, while the over layer ink uses polyfunctional polymerizable compounds (55.0% or more) that provide excellent wet spreadability. This functional segmentation ensures that each layer performs its specific function optimally without compromising the other.
Solution Approach 2:
The patent employs parameter changes by optimizing the composition ratios of polymerizable compounds in each ink layer. The under layer ink is formulated with 80.0% or more monofunctional polymerizable compounds to maximize adhesion, while the over layer ink is formulated with 55.0% or more polyfunctional polymerizable compounds to maximize wet spreadability. This parameter optimization resolves the contradiction by adjusting the chemical composition parameters independently for each layer.
3Ease of operation
If the surface tension relationship between under layer and over layer inks is adjusted to improve wet spreadability, then wet spreadability is improved, but adhesion performance deteriorates
Solution Approach 1:
The patent employs parameter changes by optimizing the composition ratios of polymerizable compounds in each ink layer. The under layer ink is formulated with 80.0% or more monofunctional polymerizable compounds to maximize adhesion, while the over layer ink is formulated with 55.0% or more polyfunctional polymerizable compounds to maximize wet spreadability. This parameter optimization resolves the contradiction by adjusting the chemical composition parameters independently for each layer.
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 set enhances the flexibility and adhesion of the under layer, while improving the wet spreadability and burying properties of the over layer ink, ensuring a stable and high-quality image formation on various recording media.
Implementation Method 1
a first curing step of forming an under layer cured film by irradiating the under layer ink on the recording medium with radioactive rays; a second curing step of forming an over layer cured film by irradiating the over layer ink on the under layer cured film with radioactive rays
Data Source
AI summary
An ink set of radiation curable ink jet compositions, includes: an under layer ink; and an over layer ink, and the under layer ink contains, as a polymerizable compound, 80.0 percent by mass or more of a monofunctional polymerizable compound with respect to a total mass of polymerizable compounds and contains 55.0 percent by mass or more of a polymerizable compound having a nitrogen heterocyclic structure and/or a polymerizable compound having a hydroxy group in total with respect to the total mass of the polymerizable compounds.