Photocurable Resin Phase Separation for Opaque ABS-Like Parts
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Solution Overview
Problem
Current photocurable compositions for stereolithography fail to produce opaque articles with the look and feel of acrylonitrile-butadiene-styrene (ABS) while maintaining high mechanical properties and thermal resistance, and they often require higher viscosity or cause issues like bubbling due to opaque additives.
Innovation Solution
A clear, low viscosity photocurable composition is developed, combining a cationically curable compound, an acrylate-containing compound, a polyol mixture, and photoinitiators, where a low molecular weight alcohol or epoxy enhances the phase separation of higher molecular weight polyols, resulting in opaque, tough, and thermally resistant ABS-like articles without increasing viscosity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If opaque additives are used to produce ABS-like articles, then the article achieves opaque appearance and improved mechanical properties, but the resin viscosity increases and bubbling occurs
Solution Approach 1:
The patent changes the molecular weight parameter of the polyol component, using higher molecular weight polyols (e.g., polyether polyols with MW 2000-20000) to achieve phase separation and opacity without the harmful effects of traditional opaque additives. This parameter change allows the system to maintain low viscosity while achieving the desired opaque appearance and mechanical properties through controlled phase separation during curing.
2Shape
If traditional photocurable compositions are used to achieve opaque appearance, then the article looks like ABS, but the resin becomes too viscous for proper stereolithography processing
Solution Approach 1:
The patent changes the molecular weight and chemical structure parameters of the polyol component to higher molecular weight polyether polyols, which provide opacity through phase separation while maintaining low viscosity. This allows the resin to remain fluid enough for stereolithography coating and curing operations while achieving the desired opaque ABS-like appearance in the final part.
Solution Approach 2:
The patent uses a dual-curing system with both cationic photoinitiators (for epoxy/cyclic ether curing) and free radical photoinitiators (for acrylate/oxetane curing) as intermediaries to achieve complete crosslinking. This dual mechanism ensures proper curing of the complex polyol-modified system while maintaining processability, allowing the resin to remain low-viscosity during handling but cure to a tough opaque material.
3Strength
If higher molecular weight polyols are used to improve toughness, then the article achieves better mechanical properties, but the phase separation is insufficient to achieve opacity
Solution Approach 1:
The patent creates a composite phase structure by combining higher molecular weight polyether polyols with epoxy and acrylate components. The polyether polyol forms dispersed microphases within the crosslinked matrix, creating a composite material structure that provides both toughness (from the polyether domains) and opacity (from the phase separation). This composite approach simultaneously achieves both mechanical performance and optical properties.
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 opaque, ABS-like articles with improved mechanical properties and thermal resistance, allowing for clear resin visibility during stereolithography, enabling process optimization and maintaining flexibility and toughness.
Implementation Method 1
a cationic photoinitiator and a free radical photoinitiator
Implementation Method 2
wherein a low molecular weight alcohol or epoxy enhances the phase separation of higher molecular weight polyols
Data Source
AI summary
The present invention provides a clear, low viscosity photocurable composition including (i) a cationically curable compound (ii) an acrylate-containing compound (iii) a polyol-containing mixture (iv) a cationic photoinitiator and (v) a free radical photoinitiator. The photocurable composition can be cured using rapid prototyping techniques to form opaque-white three-dimensional articles having ABS-like properties.