Amorphous Calcium Carbonate Paste for Stable 3D Printing
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Solution Overview
Problem
Current 3D printing technologies face limitations in stabilizing amorphous calcium carbonate (ACC) for long-term use and forming complex structures due to heat intolerance and instability, which hinders the incorporation and preservation of organic additives and the development of intricate shapes.
Innovation Solution
A paste comprising ACC doped with divalent alkaline-earth metal ions or transition metal ions, mixed with a binder and optionally a dispersant, is created using a novel process that allows for low-temperature sintering and on-demand crystallization, enabling the formation of stable 3D models through robocasting without the need for high-temperature processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If conventional 3D printing methods are used with crystalline CaCO3, then structural stability is improved, but the ability to incorporate organic additives and form intricate shapes is lost
Solution Approach 1:
The patent changes the polymorphic state of calcium carbonate from crystalline to amorphous, which fundamentally alters its properties. ACC can incorporate organic additives and form complex shapes during printing, then transforms to crystalline form afterward to gain structural stability, thus resolving the contradiction between stability and adaptability
Solution Approach 2:
The patent utilizes the phase transition capability of calcium carbonate, printing in the amorphous phase which is adaptable and can incorporate organic additives, then inducing transformation to the crystalline phase for structural stability. This phase transition approach allows the material to exhibit different properties at different stages of the process
2Stability of the object's composition
If high-temperature sintering is applied to stabilize ACC, then structural stability is improved, but organic additives are destroyed
Solution Approach 1:
The patent changes the stabilization approach from thermal (high-temperature sintering) to chemical (divalent ion doping). By incorporating divalent alkaline-earth metal ions or transition metal ions into the ACC lattice, structural stability is achieved without requiring high temperatures, thus preserving organic additives
Solution Approach 2:
The patent replaces the thermal stabilization mechanism with a chemical stabilization mechanism. Instead of using heat energy to stabilize ACC structure, divalent ion doping provides structural stability through chemical incorporation into the lattice, eliminating the harmful thermal effects on organic additives
3Ease of operation
If ACC is used for 3D printing, then ease of handling and extrusion is improved, but long-term stability under ambient conditions deteriorates
Solution Approach 1:
The patent applies preliminary action by incorporating divalent ion doping into the ACC structure before the 3D printing process. This pre-stabilization ensures that the ACC paste remains stable during storage and handling, preventing premature crystallization while maintaining printability
Solution Approach 2:
The patent creates a composite material system where ACC is combined with divalent alkaline-earth metal ions or transition metal ions. This composite approach provides both the desired ease of handling for 3D printing and long-term stability under ambient conditions through the stabilizing effect of the dopant ions
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
This approach stabilizes ACC for extended periods, allows the preservation of intricate shapes, and facilitates the incorporation of organic additives, enabling the creation of complex geometries and functional materials suitable for various applications, including drug delivery and bio-inspired materials.
Implementation Method 1
A paste comprising amorphous calcium carbonate (ACC) doped with divalent alkaline-earth metal ions or transition metal ions
Implementation Method 2
a preprepared semiliquid paste with high ceramic loading is extruded through a thin nozzle... The paste is required to provide an appropriate viscosity under stress, allowing self-support and extrudability
Implementation Method 3
Amorphous-to-crystalline transformation is known to facilitate the incorporation of organic and inorganic additives
Data Source
AI summary
The present invention relates to a paste comprising amorphous calcium carbonate (ACC) doped with divalent alkaline-earth metal ions, e.g., magnesium ions, or transition metal ions: a dry three-dimensional model made of such a paste, e.g., by 3D-printing process such as robocasting 3D-printing process; and a process for the preparation of said paste.