Photocurable Resin for Ink-Jet Stereolithography Warpage Control
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Solution Overview
Problem
Ink-jet stereo lithography methods face challenges in producing photofabrication models with complex shapes due to low heat resistance and susceptibility to deformation, as well as issues with curing shrinkage and warpage, which are not adequately addressed by existing technologies.
Innovation Solution
A modeling material comprising a monofunctional ethylenically unsaturated monomer without a urethane group, a polyfunctional ethylenically unsaturated monomer without a urethane group, a polyfunctional ethylenically unsaturated monomer with a urethane group, and a photopolymerization initiator, which together form a two-pack photocurable composition for ink-jet stereo lithography, enhancing heat resistance and mechanical properties while minimizing curing shrinkage and warpage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the degree of crosslinking of modeling material is enhanced to elevate heat resistance, then heat resistance is improved, but curing shrinkage is generated and warpage becomes very large
Solution Approach 1:
The patent changes the chemical composition parameters of the modeling material by specifying functional group concentrations (isocyanate groups: 2.7-5.0 mmol/g, hydroxyl groups: 1.5-3.0 mmol/g) and using specific monomer combinations with controlled molecular weights and functionalities. This optimized parameter set achieves adequate heat resistance while controlling curing shrinkage and warpage
Solution Approach 2:
The patent creates a composite photocurable composition combining modeling material (containing polyol, polyisocyanate, and photopolymerization initiator) with supporting material (water-soluble monomer and photopolymerization initiator). This composite approach allows the modeling material to achieve desired mechanical properties and heat resistance while the supporting material provides structural stability during curing, reducing warpage
2Productivity
If conventional photocurable resin is used in ink-jet stereo lithography, then photofabrication can be carried out, but the prepared model is low in heat resistance and is easily deformed by heat
Solution Approach 1:
The patent modifies the chemical composition of the photocurable resin by incorporating polyols with specific molecular weights (200-2000) and polyfunctionalities (2-6), polyisocyanates with controlled NCO group concentrations, and photopolymerization initiators. These parameter changes result in cured models with deflection temperatures of 80-200°C, significantly improving heat resistance while maintaining ink-jet photofabrication capability
Solution Approach 2:
The patent applies different functional components in specific concentrations within the photocurable composition: polyol (5-50 wt%), polyisocyanate (5-50 wt%), and photopolymerization initiator (0.1-10 wt%). This localized optimization of material properties ensures adequate heat resistance and mechanical strength at the molecular level while maintaining processability for ink-jet deposition
3Shape
If a photofabrication model with complex shape is prepared using existing modeling materials, then complex geometries can be achieved, but curing shrinkage occurs and warpage becomes very large
Solution Approach 1:
The patent optimizes the molecular weight range (200-2000 for polyol) and functional group concentrations (isocyanate: 2.7-5.0 mmol/g, hydroxyl: 1.5-3.0 mmol/g) to balance flexibility for complex shape formation with control over curing shrinkage. The supporting material composition (water-soluble monomer 3-45 wt%, PPG 57-97 wt%) further controls shrinkage and warpage during photofabrication of complex geometries
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 proposed solution results in photofabrication models with improved heat resistance and mechanical properties, reducing warpage and enhancing productivity in the ink-jet stereo lithography process.
Implementation Method 1
a photopolymerization initiator (D)
Data Source
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AI summary
To provide a modeling material for forming a photofabrication model excellent in heat resistance and mechanical properties and a production method of a photofabrication model excellent in productivity. A modeling material for forming a photofabrication model in ink-jet stereo lithography, including a monofunctional ethylenically unsaturated monomer (A) free from a urethane group and allowing a homopolymer thereof to have a glass transition temperature not less than 80°C, a polyfunctional ethylenically unsaturated monomer (B) free from a urethane group and allowing a homopolymer thereof to have a glass transition temperature not less than 200°C, an ethylenically unsaturated monomer (C) having a urethane group and a photopolymerization initiator (D).