Semi-crystalline Thiourethane Polymers for Additive Manufacturing
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Solution Overview
Problem
Industrial additive manufacturing technologies using polymers face limitations due to low toughness, narrow thermal operating range, and poor mechanical isotropy in 3D printed parts, particularly with resins like polyacrylate polymers which often result in brittle or soft materials with poor interlayer adhesion.
Innovation Solution
Development of semi-crystalline thiourethane polymers synthesized through anionic step-growth polymerization using monomers with thiol and isocyanate functional groups, catalyzed by a non-nucleophilic base generated from a photolatent base, to create impact-resistant materials suitable for 3D printing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If acrylate monomers are used for stereolithography, then rapid reaction and short printing times are achieved, but the end product is brittle or soft with low toughness
Solution Approach 1:
The patent changes the chemical parameters of the resin system by using thiol-isocyanate chemistry instead of traditional acrylate photopolymerization. This fundamental chemical parameter change enables the formation of semi-crystalline thiourethane polymers with superior toughness while maintaining rapid curing through photolatent base catalysis
Solution Approach 2:
The invention creates a composite polymer structure combining crystalline and amorphous phases within the thiourethane polymer. The semi-crystalline morphology provides both the toughness needed to overcome brittleness and the rapid curing characteristics required for productive printing
2Strength
If hybrid resins using acrylates and epoxides are used, then tougher end-polymers with rapid curing are produced, but viscosity increases leading to longer printing time and higher cost
Solution Approach 1:
The patent changes the chemical composition parameters by eliminating high-viscosity epoxides and using thiol-isocyanate monomers instead. This parameter change maintains toughness through semi-crystalline structure formation while reducing viscosity to enable rapid printing
3Ease of manufacture
If 3D printed parts are produced using conventional resins, then manufacturing is achieved, but poor interlayer adhesion results in poor mechanical performance perpendicular to printed layers
Solution Approach 1:
The patent changes the material parameters by using semi-crystalline thiourethane polymers that exhibit improved layer bonding characteristics. The unique polymer structure enables better interlayer adhesion while maintaining ease of manufacture through additive manufacturing processes
4Ease of manufacture
If amorphous structure polymers are used, then manufacturing is achieved, but performance is restricted compared to semi-crystalline engineering plastics
Solution Approach 1:
The patent fundamentally changes the structural parameter by designing monomers that self-assemble into semi-crystalline structures during polymerization. This parameter change delivers engineering plastic-level performance while maintaining additive manufacturing ease through the photopolymerization process
Solution Approach 2:
The invention creates a composite microstructure with both crystalline and amorphous phases. The crystalline regions provide the enhanced performance and thermal stability of engineering plastics, while the amorphous regions maintain processability and ease of manufacture
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 semi-crystalline thiourethane polymers exhibit enhanced toughness and mechanical properties, enabling the production of robust 3D printed parts with improved interlayer adhesion and thermal stability, suitable for various applications including bio-implantable materials and protective coatings.
Implementation Method 1
photo-initiated decomposition of a photolatent base
Implementation Method 2
anionic step-growth polymerization reaction that is catalyzed by a non-nucleophillic base
Implementation Method 3
semi-crystalline forms of such polymers
Data Source
Figure 1
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Figure 2B
AI summary
A semi-crystalline thiourethane polymer. The semi-crystalline thiourethane polymer comprises a sequential chain of a first type of monomer covalently bonded to a second type of monomer via thiourethane linkages. Each of the first type of monomer includes two or more thiol functional groups and each of the second type of monomer includes two or more isocyanate functional groups. The first and second types of monomers are polymerized together in an anionic step-growth polymerization reaction that is catalyzed by a non-nucleophillic base having a pKa greater than 7, produced by photo-initiated decomposition of a photolatent base. A method of synthesizing, and polymer jetting and stereolithography methods of manufacturing a polymer part, are also disclosed.