Photocurable Ink Yellowing Adjustment via Complementary Light
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Solution Overview
Problem
Photocurable transparent inks for three-dimensional molding often yellow due to quinone structures, incomplete reaction of photoinitiators, highly active radicals, and aging of resin components, leading to unsatisfactory transparency and appearance of printed articles.
Innovation Solution
A photocurable transparent ink composition incorporating a yellowing adjusting agent that absorbs light in the 560 nm to 650 nm wavelength range, complementarily reflecting blue or violet light to counteract yellowing, comprising 60-125 parts of a photocuring agent, 0.01-5 parts of the yellowing adjusting agent, 0.5-5 parts of a photoinitiator, and 0.5-5 parts of an auxiliary agent, with specific oligomers and monomers selected for low shrinkage and high transparency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If photocurable transparent ink is used for three-dimensional molding, then curing speed and efficiency are improved, but yellowing of printed articles occurs due to photoinitiator decomposition, incomplete reaction, and resin aging
Solution Approach 1:
The patent converts the harmful yellowing effect into a beneficial one by adding a yellowing adjusting agent that absorbs yellow light (560-650 nm) and reflects blue or violet light. This agent transforms the yellowing problem into an opportunity to achieve white or transparent appearance through complementary color theory, where the reflected blue/violet light combines with the yellowed background to produce a neutral white perception.
Solution Approach 2:
The patent applies color theory by introducing a yellowing adjusting agent with specific optical properties that absorbs light in the 560-650 nm wavelength range (yellow light) and reflects complementary blue or violet light. This color adjustment mechanism allows the ink composition to maintain white or transparent appearance despite the inherent yellowing from photoinitiators and resin aging.
2Object-generated harmful factors
If yellowing adjusting agent is added to counteract yellowing, then transparency and appearance are improved, but ink composition complexity increases
Solution Approach 1:
The patent controls the content of the yellowing adjusting agent within a specific range (0.01-5 parts by weight per 100 parts of photocuring agent) to achieve the desired optical effect without excessive complexity. By optimizing this parameter, the patent balances transparency improvement with composition simplicity, ensuring the agent provides sufficient yellow light absorption while maintaining manageable ink formulation.
3Productivity
If photoinitiator is used to promote photocuring, then curing efficiency is improved, but quinone structures and residual photoinitiator cause yellowing
Solution Approach 1:
The patent introduces a yellowing adjusting agent as an intermediary substance that mediates between the yellowing caused by photoinitiator decomposition and the desired transparent appearance. This agent absorbs the harmful yellow light from quinone structures and residual photoinitiators, converting it into reflected blue/violet light that combines to produce a neutral white or transparent appearance, thereby protecting the optical quality of the printed article.
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 effectively prevents yellowing, resulting in a whiter, more transparent, and brighter appearance of printed articles with minimal shrinkage and expanded raw material selection, suitable for high-viscosity resins and inkjet printing at low temperatures.
Implementation Method 1
the photoinitiator is excited to generate a radical or a cation under an irradiation of light, and the radical or the cation promotes the photocuring agent to polymerize to cure the ink
Implementation Method 2
the yellowing adjusting agent can absorb light in a wavelength range of 560 nm to 650 nm, so that the photocurable transparent ink composition for three-dimensional molding appears transparent
Data Source
AI summary
A photocurable transparent ink composition for three-dimensional molding includes the following components in parts by weight: 60-125 parts of a photocuring agent, 0.01-5 parts of a yellowing adjusting agent, 0.5-5 parts of a photoinitiator, and 0.5-5 parts of an auxiliary agent, where the yellowing adjusting agent can absorb light in a wavelength range of 560 nm to 650 nm, so that the ink composition appears transparent. The photocurable transparent ink composition for three-dimensional molding can prevent yellowing of a printed article and make the printed article show a whiter, more transparent, and brighter appearance.