UV Curable Inkjet Inks for Scratch-Resistant Flexible Coatings
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Solution Overview
Problem
UV curable inkjet inks face challenges in achieving a balance between scratch resistance and flexibility, with existing solutions either compromising on one aspect or requiring high jetting temperatures that increase energy consumption and limit substrate options.
Innovation Solution
Increasing the viscosity of UV curable inkjet inks to 16.0 mPa·s or more and adjusting the organic pigment concentration between 6.5 wt% and 13.0 wt%, while controlling the amount of polyfunctional polymerizable compounds, to achieve thinner ink layers with improved touch and feel on plastics and textiles, and reducing satellite formation during printing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If thick, highly cross-linked ink layers are applied to achieve high scratch resistance, then scratch resistance is improved, but flexibility deteriorates
Solution Approach 1:
The patent applies parameter changes by precisely controlling the viscosity of the inkjet ink within a specific range (10-50 mPa·s at 25°C) and adjusting the concentration of polyfunctional polymerizable compounds (20-60 wt%). These parameter optimizations enable the formation of thinner ink layers that achieve both scratch resistance and flexibility without requiring thick cross-linked coatings
Solution Approach 2:
The patent uses composite materials by combining monofunctional and polyfunctional polymerizable compounds in specific ratios, along with pigments and photoinitiators, to create an ink composition that forms a cured film with balanced mechanical properties. This composite approach allows the ink layer to simultaneously achieve scratch resistance and flexibility
2Ease of operation
If high jetting temperatures (80°C to 140°C) are used to achieve appropriate jetting viscosity, then jetting viscosity is improved, but energy consumption increases and substrate options are limited
Solution Approach 1:
The patent fundamentally changes the viscosity parameter by formulating the ink to have a controlled viscosity range (10-50 mPa·s at 25°C) through selective monomer and oligomer combinations. This allows the ink to be jetted at or near room temperature, eliminating the need for high-temperature heating systems and expanding substrate compatibility to include temperature-sensitive materials
3Ease of operation
If high jetting temperatures (80°C to 140°C) are used to achieve appropriate jetting viscosity, then jetting viscosity is improved, but substrate options are limited to non-thermosensitive substrates
Solution Approach 1:
The patent changes the temperature parameter by enabling jetting at or near room temperature through optimized ink viscosity (10-50 mPa·s at 25°C). This temperature reduction expands substrate compatibility to include thermosensitive materials that cannot withstand high-temperature jetting processes
4Manufacturing precision
If viscosity is increased to reduce satellite formation, then printing quality is improved, but jetting difficulty increases
Solution Approach 1:
The patent optimizes the viscosity parameter within a precise range (10-50 mPa·s at 25°C) that balances jetting performance and print quality. This controlled viscosity range ensures the ink is fluid enough for easy jetting while maintaining sufficient cohesion to minimize satellite formation and improve printing precision
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
This approach results in a better compromise between scratch resistance and flexibility, enhancing the reliability and quality of printed images, particularly on non-absorbing substrates like plastics, while maintaining high cure speed and reducing energy consumption.
Implementation Method 1
UV curable inkjet inks are particularly preferred because high quality colour images can be printed on non-absorbing ink-receivers
Data Source
AI summary
A liquid UV curable inkjet ink includes one or more photoinitiators, an organic colour pigment, and a polymerizable composition containing at least one monofunctional polymerizable compound and at least one polyfunctional polymerizable compound, wherein the organic colour pigment is present in an amount of 6.0 to 13.0 wt % based on the total weight of the liquid UV curable inkjet ink; the at least one polyfunctional polymerizable compound is present in an amount of at least 20.0 wt % based on the total weight of the polymerizable composition; and the UV curable inkjet ink has a viscosity at 45° C. and a shear rate of 10 s−1 of at least 16.0 mPa.s.