Low-Viscosity Dental Aligner Mold Resin via Cycloaliphatic Epoxy
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Solution Overview
Problem
Current liquid radiation curable resins for additive manufacturing, particularly in dental aligner mold production, face challenges with high viscosity leading to inefficient processing, lack of dimensional and mechanical stability, and inadequate long-term properties, which hinder the production of molds with high precision and strength.
Innovation Solution
A liquid radiation curable resin composition comprising 50-80 wt.% cycloaliphatic epoxy, 5-30 wt.% oxetane, a (meth)acrylate component, a cationic photoinitiator, and a free-radical photoinitiator, with a viscosity of 75-300 mPa·s, allowing for low viscosity and stability, enabling deep dipping and eliminating the need for recoating and dwell times, while maintaining mechanical integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional liquid radiation curable resins are used for additive manufacturing, then the resin can form molds, but the high viscosity leads to inefficient processing and requires recoating operations
Solution Approach 1:
The patent changes the physical parameter of viscosity by formulating a resin composition with specific components (cycloaliphatic epoxy, oxetane, (meth)acrylate) and ratios, achieving viscosity of 75-300 mPa·s at 30°C. This parameter change eliminates the need for recoating operations and enables deep dipping processing, directly improving productivity and reducing process complexity
Solution Approach 2:
The patent uses a composite resin system combining cycloaliphatic epoxy (50-80 wt%), oxetane (5-30 wt%), and (meth)acrylate components with photoinitiators. This composite formulation achieves the optimal balance of low viscosity for efficient processing while maintaining mechanical strength and dimensional stability, resolving the contradiction between processing efficiency and mold quality
2Strength
If conventional resins are used, then processing can proceed, but dimensional stability and mechanical strength of the green model are insufficient
Solution Approach 1:
The composite resin system combining cycloaliphatic epoxy, oxetane, and (meth)acrylate components creates a synergistic effect where the epoxy provides mechanical strength, the oxetane contributes to dimensional stability, and the (meth)acrylate ensures proper curing characteristics. This composite approach simultaneously achieves high green strength and dimensional precision
Solution Approach 2:
The patent optimizes the chemical composition parameters and ratios of the resin components to achieve the desired balance between green strength and dimensional stability. The specific formulation with 50-80 wt% cycloaliphatic epoxy and 5-30 wt% oxetane creates a resin that maintains structural integrity during processing while minimizing deformation
3Productivity
If high viscosity resin is used, then the resin maintains structural integrity, but processing becomes inefficient and requires additional time
Solution Approach 1:
The patent changes the viscosity parameter to 75-300 mPa·s at 30°C, which is low enough to eliminate dwell time requirements and enable continuous deep dipping processing. This parameter optimization directly increases production speed while maintaining sufficient structural integrity for mold formation
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 resin composition achieves low viscosity and stability, facilitating efficient processing, high dimensional precision, and long-term mechanical strength, suitable for dental aligner molds, reducing production time and costs.
Implementation Method 1
liquid radiation curable resin composition... exposing the first liquid layer imagewise to actinic radiation to form an imaged cross-section... causing substantial curing of the first liquid layer
Implementation Method 2
viscosity of between 75 and 300 mPa·s... allowing for low viscosity and stability, enabling deep dipping and eliminating the need for recoating and dwell times
Data Source
AI summary
Liquid radiation curable resin compositions for additive manufacturing comprising: from about 5 to about 30 wt.% of an oxetane; a (meth)acrylate component; a cationic photoinitiator; a free-radical photoinitiator; and from about 50 to about 80 wt.% of an epoxy, which further comprises a cycloaliphatic epoxy component, and an epoxy component having an aromatic glycidyl ether group, wherein the majority of the epoxy is the cycloaliphatic epoxy component are described and claimed. Also described and claimed is a process for using the liquid radiation curable resins for additive manufacturing to create molds for dental aligners, and the three-dimensional molds made from the liquid radiation curable resins for additive manufacturing.