Photocurable 3D Printing Composition for Flexible Objects
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Solution Overview
Problem
Current three-dimensional printing technologies face challenges in producing flexible objects with a balance of high tensile strength and percent elongation at break, as existing materials either prioritize one property over the other, leading to inadequate mechanical integrity for flexible objects with desired Shore A hardness.
Innovation Solution
A photocurable composition comprising 20-70 wt% urethane acrylate, 20-60 wt% multifunctional epoxide, 1-15 wt% monomer, and 1-8 wt% photoinitiator components, where the urethane acrylate is derived from a capping reaction of acrylate and isocyanate-terminated prepolymer, and the multifunctional epoxide includes difunctional cycloaliphatic or aromatic epoxides, used in stereolithography-based processes to achieve flexible objects with specific mechanical properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If existing materials prioritize tensile strength, then mechanical integrity is improved, but percent elongation at break deteriorates
Solution Approach 1:
The patent uses a composite photopolymer formulation combining epoxy resin (providing strength) with polyene compound and low molecular weight ene compound (providing flexibility and elongation). This composite approach allows simultaneous achievement of high tensile strength and high percent elongation at break, resolving the contradiction between mechanical integrity and flexibility.
2Strength
If existing materials prioritize Shore A hardness, then mechanical integrity is improved, but flexibility deteriorates
Solution Approach 1:
The patent modifies the chemical composition parameters of the photopolymer by incorporating specific ratios of epoxy resin, polyene compound, and low molecular weight ene compound. By adjusting these compositional parameters, the material achieves optimal balance between Shore A hardness (mechanical integrity) and flexibility, allowing the object to maintain structural strength while remaining deformable.
3Device complexity
If single-material formulation is used, then material simplicity is maintained, but balanced mechanical properties deteriorate
Solution Approach 1:
The patent employs a multi-component composite photopolymer system consisting of epoxy resin, polyene compound, and low molecular weight ene compound. This composite formulation enables balanced mechanical properties including both strength and flexibility that cannot be achieved with single-material formulations, while maintaining relatively simple processing through stereolithography.
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 a balance of Shore A hardness, percent elongation at break, and tensile strength, providing enhanced mechanical integrity and uniform mechanical behavior suitable for flexible three-dimensional printed objects, with distinct glass transition temperatures allowing for deformability and reinforcement.
Implementation Method 1
a photopolymer composition comprising a polyene compound, an epoxy resin and optionally a radical initiator and a low molecular weight ene compound
Implementation Method 2
subsequent cross-sectional layers are cured on top of previous layer(s) to obtain a 3-D printed object
Data Source
Figure 1
AI summary
A three-dimensional printing photocurable composition includes from 20 wt% to 70 wt% of an urethane acrylate component, from 20 wt% to 60 wt% of a multifunctional epoxide component, from 1 wt% to 15 wt% of a monomer component, and from 1 wt% to 8 wt% of a photoinitiator component, based on the total weight of the composition. The urethane acrylate component includes the capping reaction product of an acrylate and an isocyanate terminated prepolymer and the isocyanate-terminated prepolymer is the reaction product of a polyisocyanate and at least one polyol having a molecular weight of at least 3000 g/mol. The multifunctional epoxide component includes one or more multifunctional epoxides. The monomer component includes at least one of a multifunctional acrylate monomer and a multifunctional vinyl ether monomer.