TADF Photocatalyst Composition for Visible-Light Deep Resin Curing
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional photoinitiators are single-use substances requiring high content for sufficient physical properties and viscosity, limiting polymerization rate and transparency, especially in materials impermeable to UV 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, forms a photoinitiating system for efficient radical generation and polymerization using visible light.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional photoinitiators are used at high content to ensure sufficient physical properties and viscosity, 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 pair system. This parameter change enables the use of extremely low photocatalyst concentrations (0.001-0.1 wt%) while maintaining reliable curing, thereby resolving the contradiction between ensuring physical properties and achieving high polymerization rate.
Solution Approach 2:
The patent employs a composite photoinitiating system combining a photocatalyst (e.g., organic dye) with a coinitiator (e.g., ammonium salt). This composite approach creates a synergistic effect where the photocatalyst absorbs light and transfers energy to the coinitiator, which then generates radicals for polymerization. This composite system achieves both high polymerization rate and maintained physical properties at low concentrations.
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 system is designed to be regenerated and reused. After the photocatalyst absorbs light and transfers energy to the coinitiator, it returns to its ground state and can absorb light again. This self-service mechanism allows the photocatalyst to undergo multiple cycles without consumption, eliminating the loss of photoinitiator substance while maintaining reliable curing capability.
3Productivity
If UV light is used for curing, then polymerization can occur, but curing is not possible within materials that are impermeable to UV light
Solution Approach 1:
The patent changes the light wavelength parameter from UV to visible light range (400-780 nm). The photocatalyst is selected to absorb visible light, and the system is designed to work with visible light sources. This parameter change enables curing in materials that are impermeable to UV light, as visible light can penetrate deeper into materials and activate the photocatalyst system throughout the bulk material.
4Adaptability or versatility
If visible light sensitive initiators are used to increase light sensitivity, then curing becomes possible in UV-impermeable materials, but a small amount of initiator does not achieve sufficient polymerization rate
Solution Approach 1:
The patent employs a composite system where a visible light-sensitive photocatalyst is combined with a coinitiator. The photocatalyst absorbs visible light and efficiently transfers energy to the coinitiator, which then generates radicals at high efficiency. This composite approach resolves the contradiction by achieving both visible light sensitivity and high polymerization rate, with the coinitiator compensating for the low concentration of photocatalyst.
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 deep curing with high transparency and efficient polymerization rates even in UV-impermeable matrices with a small amount of photocatalyst, allowing reuse and broad application.
Implementation Method 1
a photocatalyst having thermally activated delayed fluorescence (TADF) properties
Implementation Method 2
a photocatalyst having thermally activated delayed fluorescence (TADF) properties
Implementation Method 3
a photopolymerization initiator, commonly referred to as a photoinitiator, which decomposes upon light absorption and generates free radicals or cations
Implementation Method 4
the photocured resin refers to a resin formed by polymerization of a monomer by light
Data Source
AI summary
Provided are a photocatalyst composition, a photopolymerizable composition comprising the same, and a method for preparing a photocured resin using the same. The photocatalyst composition 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, 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.