Photocurable Composition for High Clarity 3D Prototyping
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Solution Overview
Problem
Conventional photocurable compositions used in rapid prototyping for three-dimensional articles often result in low clarity and poor mechanical properties due to the miscibility issues between cationically curable and free radically curable compounds, leading to hazy and colored outputs.
Innovation Solution
A photocurable composition comprising an epoxy component with limited glycidyl content, non- or low-hydroxy containing acrylics, and a polyether polyol, along with cationic and free radical photoinitiators, which ensures compatibility and optical clarity, and improved mechanical properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional hybrid compositions containing both cationically curable and free radically curable compounds are used, then rapid prototyping can be achieved, but the articles produced have low clarity and poor mechanical properties due to miscibility issues
Solution Approach 1:
The patent modifies the chemical composition parameters by using specific epoxy compounds (particularly cycloaliphatic epoxies like 3,4-epoxycyclohexylmethyl 3,4-epoxycyclohexanecarboxylate) in combination with controlled amounts of aromatic epoxies, and selecting specific polyester polyols with particular molecular weights and hydroxyl values to achieve miscibility and high clarity while maintaining rapid curing capability
Solution Approach 2:
The invention creates a composite photocurable composition that integrates cationically curable epoxy compounds, free radically curable (meth)acrylate compounds, polyester polyols, and specific photoinitiators in optimized ratios, achieving both rapid prototyping productivity and high optical quality with improved mechanical properties
2Speed
If compositions contain aromatic acrylates or vinyl ethers, then curing speed is improved, but the articles become highly colored
Solution Approach 1:
The patent changes the chemical structure parameters by replacing aromatic acrylates with aliphatic (meth)acrylates and controlling the types and concentrations of photoinitiators to achieve fast curing without excessive coloration, while using specific epoxy compounds that maintain clarity
3Strength
If cationically curable compounds are used, then mechanical properties are improved, but the reaction rate is slower compared to free radically curable compounds
Solution Approach 1:
The invention merges cationic and free radical curing mechanisms into a hybrid system where epoxy compounds (providing mechanical strength) and (meth)acrylate compounds (providing fast curing) are combined in specific ratios with compatible photoinitiators, achieving both rapid reaction rate and improved mechanical properties
Solution Approach 2:
The patent optimizes the concentration ratios of cationic and free radical components, adjusting the amounts of epoxy compounds, (meth)acrylate compounds, and dual photoinitiators to balance curing speed and mechanical property development
4Manufacturing precision
If polyols are removed from the photocurable composition to improve clarity, then optical clarity is enhanced, but the parts become brittle
Solution Approach 1:
The patent changes the polyol parameters by selecting specific polyester polyols with controlled molecular weights (500-5000) and hydroxyl values (10-100 mg KOH/g), and optimizing their concentration (0.1-10% by weight) to maintain clarity while preventing brittleness through proper plasticization
Solution Approach 2:
The invention applies local quality by using low concentrations of specifically selected polyester polyols only where needed to maintain flexibility without compromising overall optical clarity, rather than uniform distribution of generic polyols
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 produces three-dimensional articles with high clarity and enhanced mechanical properties, such as high tensile strength, flexibility, and resistance to yellowing, suitable for applications requiring transparency and durability.
Implementation Method 1
a photocurable composition comprising (a) an epoxy component containing one or more epoxy compound(s)... (b) a (meth)acrylate component containing one or more multifunctional (meth)acrylates... (d) a cationic photoinitiator; and (e) a free radical photoinitiator
Data Source
AI summary
A photocurable composition comprising: (a) a cationically curable component preferably formed from one or more epoxy compound(s), (b) an acrylate component having no or a low amount of hydroxy groups preferably dipentaerythritol hexaacrylate, (c) a polyol component, preferably a polyether polyol, (d) a cationic photoinitiator; and (e) a free radical photoinitiator. The composition may produce when cured three-dimensional articles with high clarity and improved mechanical properties.