Cationic 3D Printing Resin Composition for Burr-Free Accuracy
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Solution Overview
Problem
Existing cationically polymerizable resin compositions used in three-dimensional photofabrication suffer from issues such as dimensional inaccuracies, formation of 'burr' on layer interfaces, increased viscosity over time, and degradation in fabrication accuracy when used repeatedly, especially in lifting photofabrication devices.
Innovation Solution
A cationically polymerizable resin composition comprising a cationically polymerizable monomer, a photocationic polymerization initiator with a photo acid generator, photosensitizer, and electron-donating thiophene compounds, along with a basic compound, enhances polymerization activity and stability, preventing 'burr' formation and maintaining accuracy even after multiple uses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a radical polymerizable resin composition is used for three-dimensional photofabrication, then the fabrication process can proceed efficiently, but polymerization shrinkage causes dimensional inaccuracy and residual stress leading to gradual distortion
Solution Approach 1:
The patent changes the polymerization mechanism from radical to cationic polymerization. This fundamental parameter change transforms the polymerization shrinkage characteristics, enabling low shrinkage curing while maintaining high fabrication efficiency. The cationic polymerization system achieves this through its unique reaction mechanism where monomers polymerize with minimal volume change, directly resolving the contradiction between productivity and manufacturing precision.
Solution Approach 2:
The patent employs a composite resin composition system combining cationically polymerizable monomers (such as epoxy compounds, oxetane compounds, or cyclic carbonate compounds) with photocationic polymerization initiators. This composite material system integrates multiple functional components that work synergistically to achieve both high fabrication efficiency and dimensional stability, eliminating the distortion problems associated with radical polymerization while maintaining productive fabrication rates.
2Manufacturing precision
If existing cationically polymerizable resin compositions are used, then polymerization shrinkage is reduced, but fabrication accuracy degrades when used repeatedly in lifting photofabrication devices
Solution Approach 1:
The patent optimizes the photocationic polymerization initiator system by selecting specific photosensitizers (thioxanthone, anthracene, or coumarin compounds) and photoacid generators with appropriate absorption characteristics. This parameter optimization ensures consistent polymerization activity across multiple uses in lifting photofabrication devices, maintaining fabrication accuracy without degradation. The selected components exhibit stable photophysical properties that prevent the reliability issues observed in existing cationic systems.
Solution Approach 2:
The patent enables continuous repeated use of the resin composition in lifting photofabrication devices without loss of performance. The cationically polymerizable monomer system maintains stable viscosity and polymerization characteristics over multiple fabrication cycles. The photocationic initiator system continues to generate active species efficiently throughout repeated use, ensuring continuous useful action and consistent fabrication accuracy across multiple operations.
3Manufacturing precision
If cationically polymerizable resin composition is used in lifting photofabrication, then low polymerization shrinkage is achieved, but 'burr' formation occurs on layer interfaces reducing surface quality
Solution Approach 1:
The patent modifies the photocationic polymerization system parameters by selecting photosensitizers with specific absorption coefficients and excitation wavelengths. This parameter change controls the depth and distribution of light penetration, ensuring uniform polymerization through the resin depth without excessive surface reaction that causes burr formation. The optimized photoacid generator concentration and type regulate the rate of cationic species generation, preventing localized over-polymerization at layer interfaces while maintaining overall dimensional accuracy.
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 composition achieves high fabrication accuracy and stability, allowing faithful reproduction of three-dimensional shapes with improved storage stability and resistance to degradation during repeated use.
Implementation Method 1
a photocationic polymerization initiator (B) including a photo acid generator (b1)... which generates cationic species by photolysis
Implementation Method 2
a cationically polymerizable monomer (A)... a cured product obtained by cationic polymerization
Data Source
AI summary
Provided is a cationically polymerizable resin composition for three-dimensional photofabrication that contains a cationically polymerizable monomer (A), a photocationic polymerization initiator (B) containing a photoacid generator (b1), a photosensitizer (b2), and an electron-donating compound (b3) that is at least one type of thiophene compound selected from the group consisting of monothiophene compounds having a π-conjugated substituent as a substituent, dithiophene compounds, and trithiophene compounds, and a basic compound (C). The content of the electron-donating compound (b3) is 0.001-10 parts by mass and the content of the basic compound (C) is 0.0001-5.0 parts by mass per 100 parts by mass of the cationically polymerizable monomer (A). Also provided is a method for producing a three-dimensional photofabricated product using this cationically polymerizable resin composition for three-dimensional photofabrication.