Photocurable Silicone Composition for Fast 3D Printing and Shelf Life
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Solution Overview
Problem
Current methods for manufacturing silicone-based structures using photocurable silicones face challenges such as compromised properties due to modifications in resin composition, slow curing times, and the need for unmodified silicones with extended shelf life and efficient photocuring processes.
Innovation Solution
A composition for 3D printing using siloxane monomers with silane functional groups, chain transfer agents, hydrosilylation catalysts, radical initiators, and photo-oxidizing agents to accelerate photocuring, enabling rapid layer formation and improved mechanical properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional Pt-catalyzed hydrosilylation chemistry is used for curing silicone, then the curing reaction proceeds effectively, but the shelf life is limited to approximately 12 hours at room temperature
Solution Approach 1:
A photo-protecting group is introduced to the Pt catalyst, which preliminarily deactivates the catalyst's activity. This preliminary action prevents premature curing reactions during storage, thereby extending shelf life while maintaining the catalyst's ability to catalyze the reaction when needed.
Solution Approach 2:
The photo-protecting group is extracted or removed upon exposure to light, activating the Pt catalyst at the appropriate time. This separation of catalyst activation from storage allows the system to maintain stability during storage while enabling effective curing when exposed to light.
2Adaptability or versatility
If photocurable functional groups (acrylates or thiol-ene functionalities) are introduced to enable additive manufacturing, then photocuring capability is achieved, but the mechanical properties and overall performance are compromised
Solution Approach 1:
A photo-protecting group serves as an intermediary between the Pt catalyst and the silane functional groups. This intermediary allows light to activate the catalyst without requiring the silicone resin to contain photocurable functional groups, thus preserving the resin's mechanical properties while enabling photocuring capability.
3Adaptability or versatility
If light-mediated curing techniques are used for layer-by-layer printing, then additive manufacturing of complex geometries is enabled, but the curing process is slow requiring five to ten minutes per layer
Solution Approach 1:
The chemical parameters of the curing system are changed by using a photo-activated Pt-catalyzed hydrosilylation system with photo-protected catalyst. This parameter change enables much faster curing rates compared to conventional light-mediated techniques, reducing the curing time per layer from five to ten minutes to a much shorter duration, thereby significantly improving printing productivity.
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 solution allows for rapid curing of siloxane structures within minutes, extending shelf life and maintaining mechanical integrity, suitable for complex geometries in additive manufacturing.
Implementation Method 1
Thiol-mediated photo-oxidation of photocurable silicones
Implementation Method 2
a radical initiator, and a photo-oxidizing agent
Data Source
AI summary
A composition for printing a three-dimensional siloxane structure includes a siloxane monomer having at least one silane functional group, a chain transfer agent, a hydrosilylation catalyst, a radical initiator, and a photo-oxidizing agent.