Dual Cure Epoxy Inkjet Composition for 3D Printing
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Solution Overview
Problem
Three-dimensional inkjet printing faces challenges with poor mechanical properties, such as low heat deflection temperature, brittleness, and incomplete curing, leading to issues like 'bleeding' of uncured resin and inadequate mechanical performance, which necessitate post-curing of printed objects.
Innovation Solution
An inkjet composition comprising photo-polymerization reactive compounds with acryloyl groups, radical photoinitiators, epoxy compounds, and an epoxy curing catalyst, balanced to provide low viscosity for printing, stability during the process, and efficient post-curing for enhanced mechanical properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the 3D object is cured completely during the 3D printing process, then the mechanical properties are improved, but the interlayer adhesion becomes too weak and the print may fail
Solution Approach 1:
The curing process is segmented into two distinct stages: (1) partial pre-curing during inkjet printing to maintain interlayer adhesion, and (2) complete post-curing after printing to achieve optimal mechanical properties. This segmentation allows each stage to fulfill its specific function without compromising the other.
Solution Approach 2:
The inkjet composition is formulated with photopolymerization reactive compounds that enable preliminary pre-curing of each printed layer before the next layer is deposited. This preliminary action ensures sufficient green body strength during printing while leaving residual reactivity for complete post-curing.
2Ease of operation
If the inkjet composition has low viscosity, then the printing process is improved, but the composition may polymerize in the printing apparatus prior to printing
Solution Approach 1:
The composition parameters are precisely controlled: photoinitiator concentration is optimized to provide sufficient pre-curing reactivity while maintaining low viscosity for inkjet printing. The balance between these parameters prevents premature polymerization in the printing apparatus.
Solution Approach 2:
The inkjet composition acts as an intermediary with dual functionality: it provides the low viscosity needed for printing while simultaneously containing the balanced reactivity components (photopolymerization reactive compounds and photoinitiator) that prevent premature polymerization but enable effective pre-curing.
3Ease of manufacture
If uncured resin remains in the final product, then the printing process is simplified, but the mechanical performance decreases and health problems may occur
Solution Approach 1:
The useful action of curing continues from the printing stage through post-curing. The composition is formulated to maintain residual reactivity after printing, ensuring that the curing process is not interrupted but rather continues to completion during post-curing, eliminating uncured resin while maintaining simple manufacturing.
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 inkjet composition achieves sufficient green body strength and mechanical properties, preventing 'bleeding' and ensuring optimal performance by balancing pre-curing and post-curing processes, thereby addressing the limitations of existing radiation curable compositions.
Implementation Method 1
radical photoinitiator (R)
Implementation Method 2
epoxy curing catalyst (C)
Data Source
AI summary
The present invention relates to an effect pigment having optically active layers consisting of a flake of a highly reflective material with directly adjacent on one side or on both sides a layer of a semiconducting material having a bandgap of 0.1 to 3.5 eV. The effect pigment may be further coated with a coating which is optically non-active in the visible wavelength region.