UV-Curable Ink Curing with LED and Heat
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Solution Overview
Problem
Achieving a balance between desirable cure and print characteristics when using LED sources for UV-curable inks is challenging due to the narrower spectrum of UV light they produce, which can affect the curing process.
Innovation Solution
A method involving a radiation-curable ink composition with a photoinitiator content not exceeding 4.5 weight percent, irradiated with UV radiation centered at specific wavelengths (375 nm, 385 nm, or 395 nm) and heated to at least 75°C, utilizing an LED source and a heat source to facilitate curing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If LED sources are used to produce UV radiation for curing inks, then cost-effectiveness and safety are improved, but the spectrum of UV light produced becomes much narrower
Solution Approach 1:
The patent changes the wavelength parameter of UV radiation by selecting specific LED sources centered at 375 nm, 385 nm, or 395 nm, and adjusts the photoinitiator concentration parameter to not more than 4.5 weight percent, thereby achieving effective curing with LED's narrow spectrum while maintaining print quality
2Object-affected harmful factors
If LED sources are used to produce UV radiation for curing inks, then safety is improved, but the spectrum of UV light produced becomes much narrower
Solution Approach 1:
The patent changes the wavelength parameter to specific ranges (375 nm, 385 nm, or 395 nm) that are safer than traditional mercury lamp spectra, while adjusting the photoinitiator concentration to ensure complete curing despite the narrower spectrum
3Manufacturing precision
If photoinitiator content is reduced to improve print characteristics, then print quality is improved, but curing effectiveness deteriorates
Solution Approach 1:
The patent optimizes the photoinitiator concentration parameter to not more than 4.5 weight percent and combines it with specific UV wavelength parameters (375 nm, 385 nm, or 395 nm) and heat treatment at least 75°C, achieving both good print characteristics and effective curing
Solution Approach 2:
The patent creates a composite curing system combining reduced photoinitiator content with specific wavelength UV LEDs and heat treatment, where the synergistic effect of multiple parameters compensates for the reduced photoinitiator concentration while improving overall print quality
4Ease of manufacture
If UV radiation with narrow spectrum is used, then cost-effectiveness is improved, but curing completeness deteriorates
Solution Approach 1:
The patent changes the wavelength parameter to specific LED centers (375 nm, 385 nm, or 395 nm) and combines it with heat treatment at least 75°C, ensuring complete curing with cost-effective LED sources despite their narrow spectrum
Solution Approach 2:
The patent introduces heat treatment as an intermediary step that facilitates complete curing when using LED's narrow spectrum UV radiation, allowing the system to achieve curing completeness that would otherwise require more expensive broad-spectrum sources
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 ensures effective curing with improved mechanical properties and weatherability of the printed image, even with reduced photoinitiator content, by optimizing the UV wavelength and heat treatment.
Implementation Method 1
The radiation-curable ink composition comprises a photoinitiator... The deposited ink composition is irradiated with UV radiation... Such inks are cured upon exposure to UV radiation
Implementation Method 2
The irradiated ink composition is heated to a temperature of at least about 75 degrees C
Data Source
AI summary
The present disclosure relates to a method of printing a radiation-curable ink composition on a substrate. A radiation-curable ink composition is deposited onto a substrate. The radiation-curable ink composition comprises a photoinitiator in an amount of not more than about 4.5 weight %. The deposited ink composition is irradiated with UV radiation. The irradiated ink composition is heated to a temperature of at least about 75 degrees C. The UV radiation is from an LED source or is centered at a wavelength selected from the group consisting of 375 nm, about 385 nm and about 395 nm.