Optical Shaping Resin Composition for Tough, Low-Odor Curing
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Solution Overview
Problem
Existing resin compositions for stereolithographic fabrication, particularly for dental occlusal splints and denture base materials, face challenges in achieving desirable toughness, water resistance, and low odor while maintaining low viscosity, with issues such as strong odors from monomers and insufficient curing due to oxygen exposure during short light irradiation.
Innovation Solution
A resin composition comprising an α,β-unsaturated double bond group-containing compound with a nitrogen atom-containing ring structure, a (meth)acrylic acid ester compound with a boiling point of 280°C or more, a photopolymerization initiator, and optionally a polyfunctional polymerizable monomer with a molecular weight of 500 or less, along with a urethanized (meth)acrylic compound, to enhance toughness and water resistance while reducing odor and viscosity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If monomers with low polarity are used to develop flexibility and water resistance, then toughness and water resistance are improved, but curability decreases leading to poor mechanical strength
Solution Approach 1:
The patent changes the chemical parameters of the monomer components by selecting specific compounds with balanced polarity characteristics. The use of monomers containing heteroatoms (oxygen, nitrogen) in specific molecular weight ranges (500-2000) optimizes both curability and mechanical properties without compromising strength
Solution Approach 2:
The patent creates a composite resin composition by combining multiple monomer types (polyfunctional monomers, monofunctional monomers, and specific compounds with molecular weight 500-2000) in controlled ratios. This composite approach achieves synergistic effects where the combination provides both adequate curability and mechanical strength that individual components cannot achieve alone
2Ease of manufacture
If low-viscosity monomers are used to achieve low-viscosity resin composition, then ease of fabrication is improved, but odor increases due to low boiling points
Solution Approach 1:
The patent changes the viscosity parameter by selecting monomers with molecular weights in the 500-2000 range, which naturally provide lower viscosity than higher molecular weight polymers. Simultaneously, the selection of specific chemical structures (avoiding low boiling point monomers) controls the odor parameter, achieving both low viscosity and low odor
3Productivity
If short light irradiation time is used in stereolithography, then productivity is improved, but insufficient curing occurs due to oxygen exposure
Solution Approach 1:
The patent changes the photopolymerization parameters by selecting monomers with high reactivity and appropriate absorption characteristics that enable complete curing under short irradiation conditions. The specific monomer composition (including polyfunctional monomers and compounds with molecular weight 500-2000) enhances the curing efficiency, allowing adequate polymerization even with brief light exposure
Solution Approach 2:
The composite monomer system provides multiple polymerization pathways that can proceed simultaneously, ensuring complete curing even when irradiation time is limited. The synergistic interaction between different monomer types compensates for oxygen inhibition effects, maintaining curing completeness while preserving fast fabrication speed
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 enables the fabrication of high-strength, tough, and water-resistant three-dimensional objects with reduced odor, suitable for dental and medical applications, particularly dental occlusal splints and appliances for sleep apnea, through vat stereolithography.
Implementation Method 1
a photopolymerization initiator (C)
Data Source
AI summary
A resin composition for optical shaping comprising: an α,β-unsaturated double bond group-containing compound (A) having a ring structure (a) containing a nitrogen atom; a (meth)acrylic acid ester compound (B) having a boiling point of 280° C. or more at normal pressure, having a carbocyclic group, and having no nitrogen-containing heterocyclic group; a photopolymerization initiator (C); and optionally, a polyfunctional polymerizable monomer (E) having a molecular weight of 500 or less and not comprised in the α,β-unsaturated double bond group-containing compound (A) and the (meth)acrylic acid ester compound (B), wherein the content of the polyfunctional polymerizable monomer (E) having a molecular weight of 500 or less is 20 mass % or less relative to the total amount of polymerizable compounds comprised in the resin composition for optical shaping.