3D Printing Ink Gellant Liquid-Gel Transition
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Solution Overview
Problem
Commercial 3D printing inks face challenges such as reduced printing speed and resolution due to exothermic curing, which causes elevated temperatures and phase segregation of ink components, leading to viscosity changes and loss of printing precision.
Innovation Solution
Development of inks containing a gellant with terminal olefin moieties linked to hydrophobic segments via urethane, urea, or amide moieties, which maintains a gel state at ambient temperatures and undergoes a liquid-gel transition, allowing for controlled viscosity and reduced phase segregation, enabling higher print speed and resolution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the ink is jetted at elevated temperatures to reduce viscosity for printing, then the printing speed and resolution are improved, but the exothermic curing process causes elevated temperatures at the deposition surface leading to reduced viscosity and loss of printing resolution
Solution Approach 1:
The patent modifies the chemical composition parameters of the ink by incorporating specific gellants (waxes with melting points 40-80°C) and curable materials with controlled reactivity. This allows the ink to maintain stable viscosity at deposition temperatures while enabling curing at lower temperatures, thus resolving the contradiction between printing resolution and deposition surface temperature
Solution Approach 2:
The patent creates a composite ink formulation combining curable materials, gellants, and optional pigments in specific ratios. The gellant component provides thermal stability to prevent viscosity reduction during curing, while the curable material enables crosslinking. This composite structure allows simultaneous achievement of high printing resolution and controlled temperature during the process
2Manufacturing precision
If the ink exhibits high viscosity at ambient temperatures to maintain shape fidelity, then the printing resolution is improved, but the ink components undergo phase segregation over time during storage and after printing
Solution Approach 1:
The patent carefully controls the viscosity parameter within a specific range (5-50 cP at 25°C) and adjusts the gelation temperature parameter (40-80°C) to optimize the balance between shape fidelity and compositional stability. The controlled gelation temperature ensures the ink remains fluid enough for printing while gradually gelling to prevent phase segregation during storage
Solution Approach 2:
The composite ink formulation combines curable materials with specific gellants (waxes) that have carefully selected melting points. This composite structure allows the ink to maintain homogeneous composition during storage while providing sufficient viscosity at ambient temperatures for shape fidelity during printing, thus resolving the contradiction between printing resolution and compositional stability
3Productivity
If the curing process is accelerated to improve printing speed, then the productivity is improved, but the exothermic reaction causes elevated temperatures leading to reduced viscosity and loss of printing resolution
Solution Approach 1:
The patent modifies the curing parameter by selecting curable materials and gellants with appropriate glass transition temperatures and reactivity. This allows accelerated curing through chemical composition optimization rather than thermal acceleration, thus improving printing speed without causing the temperature-related viscosity reduction that would compromise printing resolution
Solution Approach 2:
The composite ink formulation with specific gellant-to-curable-material ratios enables controlled curing kinetics. The gellant provides structural stability during accelerated curing while the curable material crosslinks to form the final part. This composite approach allows high printing speed while maintaining printing resolution by preventing the temperature-induced viscosity reduction that occurs with conventional fast-curing inks
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 ink achieves higher print speed and feature resolution with reduced phase segregation, maintaining mechanical strength and optical transparency, and preventing color diffusion between adjacent voxels.
Implementation Method 1
the ink exhibits a liquid-gel transition between about 40°C and about 75°C
Implementation Method 2
The gellant can comprise a curable species such that the gellant undergoes a phase change upon curing of the ink
Data Source
Figure 1A~1D
Figure 2A~2B
AI summary
In one aspect, methods of printing a three-dimensional article are described herein. In some embodiments, a method described herein comprises jetting an ink at a temperature T1 onto a substrate at a temperature T2 to form a layer of the ink on the substrate. The method further comprises subsequently curing the layer of the ink. In some embodiments, T1 is greater than T2 and the ink in an uncured state has a liquid-gel transition temperature below T1 and above T2. Further, the layer of the ink is deposited on the substrate at a rate R1 in mg/s/in2 that is within 60% of a gelation rate R2 of the ink in inverse minutes in an uncured state at T2. The ink can comprise a curable material and a gellant.