Unsaturated Polyester Resins for SLS 3D Printing
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Solution Overview
Problem
The selective laser sintering (SLS) 3D printing technology is limited by the narrow variety of applicable polymers, primarily using crystalline polyamides, which restricts the range of material properties and requires precise temperature control due to the need for a sharp melting and crystallization point difference of 30° C. to 50° C., preventing the use of more flexible or high-performance materials.
Innovation Solution
Development of unsaturated polyester resins with a crystallization temperature between 50° C. and 70° C. and a melting temperature between 75° C. and 110° C., derived from ethylenically unsaturated monomers and aliphatic diols, which can be cross-linked with thermal initiators to form thermosetting resins, allowing for improved mechanical properties and reduced power requirements in 3D printing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If crystalline polyamides with sharp melting and crystallization points are used, then the material can be successfully processed by SLS technology, but the variety of applicable polymers is limited and material properties are restricted
Solution Approach 1:
The patent changes the thermal parameters of the polymer material by developing unsaturated polyester resins with specifically controlled crystallization temperatures (50-70°C) and melting temperatures (75-110°C). This creates a broader sintering window of 25-60°C, compared to the narrow 30-50°C window required by conventional crystalline polyamides, thereby enabling versatile material selection while maintaining SLS processability
Solution Approach 2:
The patent employs composite material strategy by creating unsaturated polyester resins that combine crystalline properties with ethylenically unsaturated functional groups. This allows the material to exhibit both the necessary crystalline structure for SLS processing and the chemical reactivity for post-processing modifications, expanding the range of achievable material properties
2Strength
If crystalline polymers with narrow sintering windows are used, then local full coalescence can be achieved, but the processing temperature must be precisely controlled and power requirements increase
Solution Approach 1:
The patent modifies the thermal parameters of the polymer to achieve a broader sintering window (25-60°C) compared to conventional materials. This broader window reduces the precision requirements for temperature control and allows the laser to operate at lower power levels while still achieving full coalescence of polymer particles, thereby reducing energy consumption
3Strength
If conventional crystalline polymers are used, then SLS processing can be performed, but mechanical properties and surface finish require additional polishing or chemical treatment
Solution Approach 1:
The patent creates a composite material system that integrates crystalline polyester resin with ethylenically unsaturated functional groups. The crystalline structure provides the necessary thermal properties for SLS processing, while the unsaturated groups enable post-processing crosslinking and surface modifications, eliminating the need for separate polishing or chemical treatment steps and directly achieving enhanced mechanical properties and surface finish
Solution Approach 2:
The patent utilizes phase transition properties of the unsaturated polyester resin, which melts at 75-110°C during SLS processing and then crystallizes upon cooling. This controlled phase transition enables proper sintering and coalescence while the subsequent crosslinking of unsaturated groups further enhances mechanical strength and surface properties without additional treatment
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 unsaturated polyester resins provide improved mechanical strength and finish without the need for polishing or chemical surface treatment, enabling the production of 3D parts with enhanced properties and reduced energy consumption.
Implementation Method 1
In a SLS system, a CO2 laser beam is used to selectively fuse or sinter the polymer particles deposited in a thin layer
Implementation Method 2
The selective laser sintering (SLS) technique for additive manufacturing (3D printing) uses a rasterized laser to scan over a bed of polymer powder, sintering it to form solid shapes
Implementation Method 3
cross-linked with thermal initiators to form thermosetting resins
Implementation Method 4
a cross-linked polyester resin prepared by contacting an unsaturated polyester with a thermal initiator
Data Source
AI summary
A composition for use in 3D printing includes an unsaturated polyester resin including an ethylenically unsaturated monomer, a first diol monomer and a second diol monomer.