Radiation-Curable Clear Ink Monomer Structure for Gloss and Odor Control
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Solution Overview
Problem
Existing ink sets with radiation-curable clear inks struggle to improve the gloss of coating films and often generate odors, particularly when using polymerizable compounds like phenoxyethyl acrylate or isobornyl acrylate, which can degrade the gloss and increase odor emission.
Innovation Solution
An ink set comprising a clear ink with polymerizable compounds, including a monomer A with a hydroxy group and a monomer B with a bulky molecular structure, where the total content of these compounds is 80% or more, along with a monofunctional monomer content of 85% or more, to enhance gloss and suppress odor, and a specific mass ratio of polymerizable compounds that adjusts the glass transition temperature for improved abrasion resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If polymerizable compounds like PEA or IBXA are used in clear ink, then the coating film can be formed, but the gloss is degraded
Solution Approach 1:
The patent changes the chemical parameters of the polymerizable compounds by selecting specific monomers with defined molecular structures (volume ≥0.26 nm³ and height direction area ≥0.25 nm²) and functional groups (hydroxy, carboxy, or amino groups). This parameter selection resolves the contradiction by achieving both proper coating film formation and improved gloss without degradation.
2Shape
If polymerizable compounds with bulky molecular structure like IBXA are used, then the gloss degradation is suppressed, but strong odor is generated
Solution Approach 1:
The patent applies local quality by specifying particular molecular structure characteristics (volume and height direction area thresholds) and functional groups for the polymerizable compounds. This localized structural specification achieves gloss improvement while the specific functional group selection (hydroxy, carboxy, or amino) controls odor generation.
Solution Approach 2:
The patent uses composite materials by combining multiple polymerizable compounds with different molecular structures and functional groups in specific proportions. This composite approach allows optimization of both gloss properties and odor suppression through synergistic effects of different monomer components.
3Shape
If monomer A with hydroxy group and monomer B with bulky structure are used in specific ratios, then gloss and odor are controlled, but abrasion resistance needs improvement
Solution Approach 1:
The patent changes the physical-chemical parameters by controlling the glass transition temperature of the polymerizable compounds to be 48°C or higher. This parameter adjustment through specific monomer selection and ratios simultaneously achieves gloss control, odor suppression, and improved abrasion resistance.
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 effectively improves the gloss and abrasion resistance of the coating film while minimizing odor generation, making it suitable for applications like signage, where the coating film's flexibility and durability are crucial.
Implementation Method 1
an ink set including a color ink and a clear ink each of which is a radiation curable ink jet ink... a polymerizable compound to be cured by radiation rays, such as ultraviolet rays
Implementation Method 2
a first curing step of emitting radiation rays on the color ink adhered to the recording medium... a second curing step of emitting radiation rays on the clear ink adhered to the recording medium
Data Source
AI summary
An ink set of radiation curable ink jet inks each of which contains polymerizable compounds, includes a color ink and a clear ink, the polymerizable compounds contained in the clear ink include a monomer A having a hydroxy group and a monomer B having a volume of 0.26 nm3 or more and a height direction area of 0.25 nm2 or more with respect to a long side each of which is defined by the Van der Waals radii, and a total content of the monomer A and the monomer B is 80 percent by mass or more with respect to a total mass of the polymerizable compounds contained in the clear ink.