TADF Photocatalyst Composition for Deep Curing Resins
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Solution Overview
Problem
Conventional photoinitiators are single-use substances requiring high content for sufficient resin properties, limiting polymerization rates and transparency, especially in materials impermeable to ultraviolet light.
Innovation Solution
A photocatalyst composition comprising a photocatalyst with thermally activated delayed fluorescence (TADF) properties and an ionic co-initiator, optimized in a molar ratio of 1:10 to 1:5,000, forming a photoinitiating system that initiates polymerization efficiently with visible light.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional photoinitiators are used at high content to ensure sufficient resin properties, then the resin can be cured, but the polymerization rate is limited and transparency is reduced
Solution Approach 1:
The patent changes the fundamental parameter of the photoinitiating system from conventional photoinitiators to a photocatalyst-coinitiator system. This parameter change enables the system to achieve both high reliability (resin properties) and high productivity (polymerization rate) simultaneously, as the photocatalyst system provides efficient radical generation with low catalyst loading, thereby improving polymerization rate while maintaining resin quality
Solution Approach 2:
The patent employs a composite photoinitiating system combining a photocatalyst and a coinitiator. This composite approach allows the system to overcome the limitations of single-component photoinitiators, achieving both sufficient resin properties and high polymerization rate through synergistic interaction between the photocatalyst and coinitiator
2Reliability
If conventional photoinitiators are used, then curing can be achieved, but the photoinitiator cannot be reused and high content is required
Solution Approach 1:
The photocatalyst in the patent exhibits self-regenerating properties through the photocatalytic cycle. After transferring electrons to the coinitiator, the photocatalyst is regenerated and can participate in another catalytic cycle. This self-service capability allows the photocatalyst to be reused multiple times, eliminating the need for high concentrations of single-use photoinitiators while maintaining reliable curing capability
Solution Approach 2:
The patent implements a system where the photocatalyst is recovered and reused through the photocatalytic cycle. The photocatalyst temporarily transfers electrons to the coinitiator during curing but is subsequently regenerated, allowing it to be discarded from the reaction transiently and then recovered for continued use, thereby reducing substance loss compared to conventional single-use photoinitiators
3Productivity
If ultraviolet light is used for curing, then polymerization can occur, but curing is not possible within materials impermeable to ultraviolet light
Solution Approach 1:
The patent changes the light wavelength parameter from ultraviolet to visible light range (400-780 nm). This parameter change enables the photoinitiating system to operate with visible light sources, expanding the application range to include materials that are impermeable to ultraviolet light while maintaining high polymerization efficiency through the photocatalyst-coinitiator system
4Adaptability or versatility
If visible light sensitive initiators are used to enable curing in UV-impermeable materials, then application range expands, but a small amount of initiator does not achieve sufficient polymerization rate
Solution Approach 1:
The patent employs a composite photoinitiating system combining a photocatalyst and a coinitiator. This composite approach specifically addresses the limitation of visible light sensitive initiators by providing a synergistic system where the photocatalyst enhances the polymerization rate. The coinitiator works together with the photocatalyst to generate radicals efficiently, achieving high polymerization rates even with small amounts of catalyst while maintaining the ability to cure in UV-impermeable materials
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
Enables high transparency and deep curing within UV-impermeable matrices with improved polymerization rates, allowing repeated use of the photocatalyst and extending penetration depth.
Implementation Method 1
the photocatalyst may be one that absorbs light in a wavelength range of 400 to 600 nm
Implementation Method 2
a photocatalyst having thermally activated delayed fluorescence (TADF) property
Implementation Method 3
forming a photoinitiating system that initiates polymerization efficiently with visible light
Implementation Method 4
a photocurable composition comprising a polymerization initiator, commonly referred to as a photoinitiator, which decomposes upon light absorption and generates free radicals or cations
Data Source
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AI summary
The present disclosure relates to a photocatalyst composition, a photopolymerizable composition comprising the same, and a method for preparing a photocured resin using the same. The photocatalyst composition of the present disclosure comprises a photocatalyst having thermally activated delayed fluorescence (TADF) property and an ionic co-initiator, and by the combined use and optimization of these components, a photoinitiating system with excellent radical generation efficiency can be formed even with a small amount of photocatalyst. Accordingly, when a monomer is polymerized using the photocatalyst composition of the present disclosure, it is possible to prepare a photocured resin with an excellent polymerization rate. Moreover, since the amount of photocatalyst used is extremely small, deep curing is also achievable. In addition, because the present disclosure initiates the polymerization reaction using visible light, curing is possible even in matrices that are impermeable to UV light, and it is also possible to prepare a resin that exhibits high transparency despite visible light absorption.