Radiation-Curable Ink Adhesion Without NVC
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Solution Overview
Problem
Radiation-curable ink jet printing inks that do not contain N-vinyl caprolactam (NVC) face challenges in achieving desirable properties such as adhesion and cure quality, as NVC exclusion can lead to poor substrate adhesion and incomplete curing.
Innovation Solution
A radiation-curable ink composition comprising a colorant, cyclohexyl (meth)acrylate, mono(meth)acrylate with cyclohexyl and/or cyclopentyl groups, cyclic trimethylolpropane formal acrylate, and minimal or no NVC, along with specific weight percentages of these components, to ensure effective curing and adhesion without relying on NVC.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If NVC is excluded from the ink composition, then the ink meets environmental safety requirements and avoids EuPIA exclusion list chemicals, but the adhesion to substrates deteriorates
Solution Approach 1:
The patent changes the chemical composition parameters by introducing specific cyclohexyl (meth)acrylates and cyclic trimethylolpropane formal acrylate to replace NVC, maintaining adhesion while reducing harmful substances. The specific structural parameters of the acrylate components are optimized to achieve both low NVC content and high adhesion.
Solution Approach 2:
The patent creates a composite monomer system combining cyclohexyl (meth)acrylate and cyclic trimethylolpropane formal acrylate in specific ratios (0.5:99.5 to 45:55 by weight). This composite approach provides synergistic effects where the combination of different acrylate structures delivers both adhesion performance and reduced NVC dependency.
2Object-affected harmful factors
If NVC is excluded from the ink composition, then the ink reduces harmful chemical content, but the cure quality deteriorates
Solution Approach 1:
The patent optimizes the molecular weight and functional group parameters of the acrylate components. The cyclohexyl (meth)acrylate with specific ring structures and the cyclic trimethylolpropane formal acrylate provide appropriate viscosity and reactivity parameters that enable complete curing without NVC, achieving both safety and reliability.
Solution Approach 2:
The patent introduces specific functional groups (cyclohexyl and cyclopentyl rings) at strategic positions in the monomer molecules. These localized structural features provide sites for effective polymerization and crosslinking, ensuring complete cure quality while maintaining low NVC content throughout the ink system.
3Object-affected harmful factors
If NVC content is reduced to 0-5 wt%, then the ink meets environmental standards, but the overall performance in adhesion and cure may deteriorate
Solution Approach 1:
The patent precisely controls the weight percentage parameters of NVC (0-5 wt%) and compensates by optimizing the concentration parameters of the alternative acrylate components. The cyclic trimethylolpropane formal acrylate and cyclohexyl (meth)acrylate are formulated at specific concentrations to maintain total solid content and reactivity levels, ensuring overall performance despite reduced NVC.
Solution Approach 2:
The patent introduces the cyclic trimethylolpropane formal acrylate as an intermediary component that mediates between the low NVC content and the required performance. This intermediary monomer provides additional polymerization functionality and crosslinking capability, bridging the performance gap created by NVC reduction and enabling both environmental compliance and reliable adhesion.
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 satisfactory cure and adhesion on various substrates, including PVC, PS, and APET, while avoiding the limitations associated with NVC exclusion, demonstrating improved performance in both cure quality and adhesion tests.
Implementation Method 1
radiation-curable inks and to their use in ink jet printing... monomers which solidify when exposed to radiation, e.g. UV light
Data Source
AI summary
A radiation-curable ink comprising (i) a colorant; (ii) a cyclohexyl acrylate of the Formula (1) wherein each R independently is C1-4-alkyl; n has a value of 1, 2 or 3; and Q is H or CH3; (iii) a monoacrylate which comprises a cyclohexyl and/or cyclopentyl ring; and (iv) 0 to 5 wt % of N-vinyl caprolactam; and (v) cyclic trimethylolpropane formal acrylate.